diff --git a/.dart_tool/package_config.json b/.dart_tool/package_config.json
index fa954ae..d7bbb38 100644
--- a/.dart_tool/package_config.json
+++ b/.dart_tool/package_config.json
@@ -326,7 +326,7 @@
       "name": "frontend_server",
       "rootUri": "../pkg/frontend_server",
       "packageUri": "lib/",
-      "languageVersion": "2.7"
+      "languageVersion": "2.15"
     },
     {
       "name": "frontend_server_client",
diff --git a/CHANGELOG.md b/CHANGELOG.md
index cb298a3..ce5d29a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -78,10 +78,6 @@
   Add a new `allowLegacyUnsafeRenegotiation` poperty to `SecurityContext`,
   which allows TLS renegotiation for client secure sockets.
 
-#### `dart:isolate`
-
-- Add `Isolate.run` to run a function in a new isolate.
-
 ### Tools
 
 #### Dart command line
diff --git a/pkg/_fe_analyzer_shared/lib/src/parser/formal_parameter_kind.dart b/pkg/_fe_analyzer_shared/lib/src/parser/formal_parameter_kind.dart
index 7e2e6f9..fa76b8b 100644
--- a/pkg/_fe_analyzer_shared/lib/src/parser/formal_parameter_kind.dart
+++ b/pkg/_fe_analyzer_shared/lib/src/parser/formal_parameter_kind.dart
@@ -4,21 +4,35 @@
 
 library _fe_analyzer_shared.parser.formal_parameter_kind;
 
-// TODO(johnniwinther): Update this to support required named arguments.
 enum FormalParameterKind {
-  mandatory,
+  requiredPositional,
+  requiredNamed,
   optionalNamed,
   optionalPositional,
 }
 
-bool isMandatoryFormalParameterKind(FormalParameterKind type) {
-  return FormalParameterKind.mandatory == type;
-}
+extension FormalParameterKindExtension on FormalParameterKind {
+  bool get isRequiredPositional {
+    return FormalParameterKind.requiredPositional == this;
+  }
 
-bool isOptionalNamedFormalParameterKind(FormalParameterKind type) {
-  return FormalParameterKind.optionalNamed == type;
-}
+  bool get isOptionalNamed {
+    return FormalParameterKind.optionalNamed == this;
+  }
 
-bool isOptionalPositionalFormalParameterKind(FormalParameterKind type) {
-  return FormalParameterKind.optionalPositional == type;
+  bool get isOptionalPositional {
+    return FormalParameterKind.optionalPositional == this;
+  }
+
+  bool get isRequiredNamed {
+    return FormalParameterKind.requiredNamed == this;
+  }
+
+  bool get isRequired => isRequiredPositional || isRequiredNamed;
+
+  bool get isOptional => isOptionalPositional || isOptionalNamed;
+
+  bool get isPositional => isRequiredPositional || isOptionalPositional;
+
+  bool get isNamed => isRequiredNamed || isOptionalNamed;
 }
diff --git a/pkg/_fe_analyzer_shared/lib/src/parser/parser_impl.dart b/pkg/_fe_analyzer_shared/lib/src/parser/parser_impl.dart
index 5292a02..4359e27 100644
--- a/pkg/_fe_analyzer_shared/lib/src/parser/parser_impl.dart
+++ b/pkg/_fe_analyzer_shared/lib/src/parser/parser_impl.dart
@@ -63,10 +63,7 @@
 import 'directive_context.dart';
 
 import 'formal_parameter_kind.dart'
-    show
-        FormalParameterKind,
-        isMandatoryFormalParameterKind,
-        isOptionalPositionalFormalParameterKind;
+    show FormalParameterKind, FormalParameterKindExtension;
 
 import 'forwarding_listener.dart' show ForwardingListener, NullListener;
 
@@ -1398,7 +1395,8 @@
         token = ensureCloseParen(token, begin);
         break;
       }
-      token = parseFormalParameter(token, FormalParameterKind.mandatory, kind);
+      token = parseFormalParameter(
+          token, FormalParameterKind.requiredPositional, kind);
       next = token.next!;
       if (!optional(',', next)) {
         Token next = token.next!;
@@ -1525,6 +1523,7 @@
     if (isModifier(next)) {
       if (optional('required', next)) {
         if (parameterKind == FormalParameterKind.optionalNamed) {
+          parameterKind = FormalParameterKind.requiredNamed;
           requiredToken = token = next;
           next = token.next!;
         }
@@ -1742,11 +1741,10 @@
       // TODO(danrubel): Consider removing the last parameter from the
       // handleValuedFormalParameter event... it appears to be unused.
       listener.handleValuedFormalParameter(equal, next);
-      if (isMandatoryFormalParameterKind(parameterKind)) {
+      if (parameterKind.isRequiredPositional) {
         reportRecoverableError(
             equal, codes.messageRequiredParameterWithDefault);
-      } else if (isOptionalPositionalFormalParameterKind(parameterKind) &&
-          identical(':', value)) {
+      } else if (parameterKind.isOptionalPositional && identical(':', value)) {
         reportRecoverableError(
             equal, codes.messagePositionalParameterWithEquals);
       } else if (inFunctionType ||
diff --git a/pkg/analyzer/lib/src/dart/resolver/invocation_inferrer.dart b/pkg/analyzer/lib/src/dart/resolver/invocation_inferrer.dart
index 9026999..2904afc 100644
--- a/pkg/analyzer/lib/src/dart/resolver/invocation_inferrer.dart
+++ b/pkg/analyzer/lib/src/dart/resolver/invocation_inferrer.dart
@@ -3,6 +3,7 @@
 // BSD-style license that can be found in the LICENSE file.
 
 import 'package:_fe_analyzer_shared/src/base/errors.dart';
+import 'package:_fe_analyzer_shared/src/deferred_closure_heuristic.dart';
 import 'package:_fe_analyzer_shared/src/flow_analysis/flow_analysis.dart';
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/element/element.dart';
@@ -13,6 +14,7 @@
 import 'package:analyzer/src/dart/element/member.dart';
 import 'package:analyzer/src/dart/element/type.dart';
 import 'package:analyzer/src/dart/element/type_algebra.dart';
+import 'package:analyzer/src/dart/element/type_system.dart';
 import 'package:analyzer/src/error/codes.dart';
 import 'package:analyzer/src/generated/resolver.dart';
 
@@ -196,16 +198,20 @@
         substitution: substitution,
         inferrer: inferrer);
     if (deferredClosures != null) {
-      if (inferrer != null) {
-        substitution = Substitution.fromPairs(
-            rawType!.typeFormals, inferrer.partialInfer());
+      for (var stage in _ClosureDependencies(resolver.typeSystem,
+              deferredClosures, rawType?.typeFormals.toSet() ?? const {})
+          .planClosureReconciliationStages()) {
+        if (inferrer != null) {
+          substitution = Substitution.fromPairs(
+              rawType!.typeFormals, inferrer.partialInfer());
+        }
+        _resolveDeferredClosures(
+            rawType: rawType,
+            deferredClosures: stage,
+            identicalInfo: identicalInfo,
+            substitution: substitution,
+            inferrer: inferrer);
       }
-      _resolveDeferredClosures(
-          rawType: rawType,
-          deferredClosures: deferredClosures,
-          identicalInfo: identicalInfo,
-          substitution: substitution,
-          inferrer: inferrer);
     }
 
     if (inferrer != null) {
@@ -424,7 +430,7 @@
   /// Resolves any closures that were deferred by [_visitArguments].
   void _resolveDeferredClosures(
       {required FunctionType? rawType,
-      required List<_DeferredClosure> deferredClosures,
+      required Iterable<_DeferredClosure> deferredClosures,
       List<EqualityInfo<PromotableElement, DartType>?>? identicalInfo,
       Substitution? substitution,
       GenericInferrer? inferrer}) {
@@ -601,6 +607,50 @@
   }
 }
 
+class _ClosureDependencies
+    extends ClosureDependencies<TypeParameterElement, _DeferredClosure> {
+  final TypeSystemImpl _typeSystem;
+
+  final Set<TypeParameterElement> _typeVariables;
+
+  _ClosureDependencies(this._typeSystem, Iterable<_DeferredClosure> closures,
+      this._typeVariables)
+      : super(closures, _typeVariables);
+
+  @override
+  Iterable<TypeParameterElement> typeVarsFreeInClosureArguments(
+      _DeferredClosure closure) {
+    var type = closure.parameter?.type;
+    if (type is FunctionType) {
+      Set<TypeParameterElement> result = {};
+      for (var parameter in type.parameters) {
+        result.addAll(_typeSystem.getFreeParameters(parameter.type,
+                candidates: _typeVariables) ??
+            const []);
+      }
+      return result;
+    } else {
+      return const [];
+    }
+  }
+
+  @override
+  Iterable<TypeParameterElement> typeVarsFreeInClosureReturns(
+      _DeferredClosure closure) {
+    var type = closure.parameter?.type;
+    if (type is FunctionType) {
+      return _typeSystem.getFreeParameters(type.returnType,
+              candidates: _typeVariables) ??
+          const [];
+    } else if (type != null) {
+      return _typeSystem.getFreeParameters(type, candidates: _typeVariables) ??
+          const [];
+    } else {
+      return const [];
+    }
+  }
+}
+
 /// Information about an invocation argument that needs to be resolved later due
 /// to the fact that it's a closure and the `inference-update-1` feature is
 /// enabled.
diff --git a/pkg/analyzer/lib/src/fasta/ast_builder.dart b/pkg/analyzer/lib/src/fasta/ast_builder.dart
index 612e610..e14406b 100644
--- a/pkg/analyzer/lib/src/fasta/ast_builder.dart
+++ b/pkg/analyzer/lib/src/fasta/ast_builder.dart
@@ -1621,8 +1621,7 @@
       }
     }
 
-    ParameterKind analyzerKind =
-        _toAnalyzerParameterKind(kind, requiredKeyword);
+    ParameterKind analyzerKind = _toAnalyzerParameterKind(kind);
     FormalParameter parameter = node;
     if (analyzerKind != ParameterKind.REQUIRED) {
       parameter = ast.defaultFormalParameter(
@@ -4336,17 +4335,16 @@
     );
   }
 
-  ParameterKind _toAnalyzerParameterKind(
-      FormalParameterKind type, Token? requiredKeyword) {
-    if (type == FormalParameterKind.optionalPositional) {
-      return ParameterKind.POSITIONAL;
-    } else if (type == FormalParameterKind.optionalNamed) {
-      if (requiredKeyword != null) {
+  ParameterKind _toAnalyzerParameterKind(FormalParameterKind type) {
+    switch (type) {
+      case FormalParameterKind.requiredPositional:
+        return ParameterKind.REQUIRED;
+      case FormalParameterKind.requiredNamed:
         return ParameterKind.NAMED_REQUIRED;
-      }
-      return ParameterKind.NAMED;
-    } else {
-      return ParameterKind.REQUIRED;
+      case FormalParameterKind.optionalNamed:
+        return ParameterKind.NAMED;
+      case FormalParameterKind.optionalPositional:
+        return ParameterKind.POSITIONAL;
     }
   }
 
diff --git a/pkg/analyzer/test/src/dart/resolution/type_inference/inference_update_1_test.dart b/pkg/analyzer/test/src/dart/resolution/type_inference/inference_update_1_test.dart
index be66958..f6700c42 100644
--- a/pkg/analyzer/test/src/dart/resolution/type_inference/inference_update_1_test.dart
+++ b/pkg/analyzer/test/src/dart/resolution/type_inference/inference_update_1_test.dart
@@ -34,6 +34,14 @@
 mixin HorizontalInferenceTestCases on PubPackageResolutionTest {
   bool get _isEnabled => experiments.contains(EnableString.inference_update_1);
 
+  test_closure_passed_to_dynamic() async {
+    await assertNoErrorsInCode('''
+test(dynamic d) => d(() {});
+''');
+    // No further assertions; we just want to make sure the interaction with a
+    // dynamic receiver doesn't lead to a crash.
+  }
+
   test_closure_passed_to_identical() async {
     await assertNoErrorsInCode('''
 test() => identical(() {}, () {});
@@ -70,6 +78,84 @@
     }
   }
 
+  test_horizontal_inference_closure_as_parameter_type() async {
+    // Test the case where a closure is passed to a parameter whose declared
+    // type is not a function but instead a type parameter.  We should still
+    // pick up the appropriate dependencies.
+    await assertErrorsInCode('''
+U f<T, U>(T t, U Function(T) g) => throw '';
+test() {
+  var a = f(() => 0, (h) => [h()]);
+}
+''', [
+      error(HintCode.UNUSED_LOCAL_VARIABLE, 60, 1),
+      if (!_isEnabled)
+        error(
+            CompileTimeErrorCode.UNCHECKED_INVOCATION_OF_NULLABLE_VALUE, 83, 1),
+    ]);
+    assertType(findNode.methodInvocation('f(').typeArgumentTypes![0],
+        'int Function()');
+    assertType(findNode.methodInvocation('f(').typeArgumentTypes![1],
+        _isEnabled ? 'List<int>' : 'List<dynamic>');
+    assertType(
+        findNode.methodInvocation('f(').staticInvokeType,
+        _isEnabled
+            ? 'List<int> Function(int Function(), '
+                'List<int> Function(int Function()))'
+            : 'List<dynamic> Function(int Function(), '
+                'List<dynamic> Function(int Function()))');
+    assertType(findNode.simpleParameter('h)').declaredElement!.type,
+        _isEnabled ? 'int Function()' : 'Object?');
+    assertType(findNode.variableDeclaration('a =').declaredElement!.type,
+        _isEnabled ? 'List<int>' : 'List<dynamic>');
+  }
+
+  test_horizontal_inference_propagate_to_earlier_closure() async {
+    await assertErrorsInCode('''
+U f<T, U>(U Function(T) g, T Function() h) => throw '';
+test() {
+  var a = f((x) => [x], () => 0);
+}
+''', [
+      error(HintCode.UNUSED_LOCAL_VARIABLE, 71, 1),
+    ]);
+    assertType(findNode.methodInvocation('f(').typeArgumentTypes![0], 'int');
+    assertType(findNode.methodInvocation('f(').typeArgumentTypes![1],
+        _isEnabled ? 'List<int>' : 'List<Object?>');
+    assertType(
+        findNode.methodInvocation('f(').staticInvokeType,
+        _isEnabled
+            ? 'List<int> Function(List<int> Function(int), int Function())'
+            : 'List<Object?> Function(List<Object?> Function(int), int Function())');
+    assertType(findNode.simpleParameter('x)').declaredElement!.type,
+        _isEnabled ? 'int' : 'Object?');
+    assertType(findNode.variableDeclaration('a =').declaredElement!.type,
+        _isEnabled ? 'List<int>' : 'List<Object?>');
+  }
+
+  test_horizontal_inference_propagate_to_later_closure() async {
+    await assertErrorsInCode('''
+U f<T, U>(T Function() g, U Function(T) h) => throw '';
+test() {
+  var a = f(() => 0, (x) => [x]);
+}
+''', [
+      error(HintCode.UNUSED_LOCAL_VARIABLE, 71, 1),
+    ]);
+    assertType(findNode.methodInvocation('f(').typeArgumentTypes![0], 'int');
+    assertType(findNode.methodInvocation('f(').typeArgumentTypes![1],
+        _isEnabled ? 'List<int>' : 'List<Object?>');
+    assertType(
+        findNode.methodInvocation('f(').staticInvokeType,
+        _isEnabled
+            ? 'List<int> Function(int Function(), List<int> Function(int))'
+            : 'List<Object?> Function(int Function(), List<Object?> Function(int))');
+    assertType(findNode.simpleParameter('x)').declaredElement!.type,
+        _isEnabled ? 'int' : 'Object?');
+    assertType(findNode.variableDeclaration('a =').declaredElement!.type,
+        _isEnabled ? 'List<int>' : 'List<Object?>');
+  }
+
   test_horizontal_inference_propagate_to_return_type() async {
     await assertErrorsInCode('''
 U f<T, U>(T t, U Function(T) g) => throw '';
diff --git a/pkg/front_end/lib/src/fasta/builder/formal_parameter_builder.dart b/pkg/front_end/lib/src/fasta/builder/formal_parameter_builder.dart
index d35c1bf..a054ace 100644
--- a/pkg/front_end/lib/src/fasta/builder/formal_parameter_builder.dart
+++ b/pkg/front_end/lib/src/fasta/builder/formal_parameter_builder.dart
@@ -5,12 +5,7 @@
 library fasta.formal_parameter_builder;
 
 import 'package:_fe_analyzer_shared/src/parser/formal_parameter_kind.dart'
-    show
-        isMandatoryFormalParameterKind,
-        isOptionalNamedFormalParameterKind,
-        isOptionalPositionalFormalParameterKind;
-import 'package:_fe_analyzer_shared/src/parser/parser.dart'
-    show FormalParameterKind;
+    show FormalParameterKind, FormalParameterKindExtension;
 import 'package:_fe_analyzer_shared/src/scanner/scanner.dart' show Token;
 import 'package:kernel/ast.dart'
     show DartType, DynamicType, Expression, VariableDeclaration;
@@ -35,18 +30,42 @@
 import 'type_builder.dart';
 import 'variable_builder.dart';
 
+abstract class ParameterBuilder {
+  /// List of metadata builders for the metadata declared on this parameter.
+  List<MetadataBuilder>? get metadata;
+  TypeBuilder? get type;
+
+  /// The kind of this parameter, i.e. if it's required, positional optional,
+  /// or named optional.
+  FormalParameterKind get kind;
+
+  bool get isPositional;
+  bool get isRequiredPositional;
+  bool get isNamed;
+  bool get isRequiredNamed;
+
+  String? get name;
+
+  ParameterBuilder clone(
+      List<NamedTypeBuilder> newTypes,
+      SourceLibraryBuilder contextLibrary,
+      TypeParameterScopeBuilder contextDeclaration);
+}
+
 /// A builder for a formal parameter, i.e. a parameter on a method or
 /// constructor.
 class FormalParameterBuilder extends ModifierBuilderImpl
-    implements VariableBuilder {
+    implements VariableBuilder, ParameterBuilder {
   static const String noNameSentinel = 'no name sentinel';
 
   /// List of metadata builders for the metadata declared on this parameter.
+  @override
   final List<MetadataBuilder>? metadata;
 
   @override
   final int modifiers;
 
+  @override
   final TypeBuilder? type;
 
   @override
@@ -55,9 +74,8 @@
   @override
   final Uri? fileUri;
 
-  /// The kind of this parameter, i.e. if it's required, positional optional,
-  /// or named optional.
-  FormalParameterKind kind = FormalParameterKind.mandatory;
+  @override
+  final FormalParameterKind kind;
 
   /// The variable declaration created for this formal parameter.
   @override
@@ -76,8 +94,8 @@
 
   final bool isExtensionThis;
 
-  FormalParameterBuilder(this.metadata, this.modifiers, this.type, this.name,
-      LibraryBuilder? compilationUnit, int charOffset,
+  FormalParameterBuilder(this.metadata, this.kind, this.modifiers, this.type,
+      this.name, LibraryBuilder? compilationUnit, int charOffset,
       {Uri? fileUri, this.isExtensionThis: false})
       : this.fileUri = fileUri ?? compilationUnit?.fileUri,
         super(compilationUnit, charOffset);
@@ -85,21 +103,23 @@
   @override
   String get debugName => "FormalParameterBuilder";
 
-  // TODO(johnniwinther): Cleanup `isRequired` semantics in face of required
-  // named parameters.
-  bool get isRequired => isMandatoryFormalParameterKind(kind);
+  @override
+  bool get isRequiredPositional => kind.isRequiredPositional;
 
-  // TODO(johnniwinther): Rename to `isRequired`.
-  bool get isNamedRequired => (modifiers & requiredMask) != 0;
+  // TODO(johnniwinther): This was previously named `isOptional` so we might
+  // have some uses that intended to use the now existing `isOptional` method.
+  bool get isOptionalPositional => !isRequiredPositional;
 
-  bool get isPositional {
-    return isOptionalPositionalFormalParameterKind(kind) ||
-        isMandatoryFormalParameterKind(kind);
-  }
+  @override
+  bool get isRequiredNamed => kind.isRequiredNamed;
 
-  bool get isNamed => isOptionalNamedFormalParameterKind(kind);
+  @override
+  bool get isPositional => kind.isPositional;
 
-  bool get isOptional => !isRequired;
+  @override
+  bool get isNamed => kind.isNamed;
+
+  bool get isOptional => kind.isOptional;
 
   @override
   bool get isLocal => true;
@@ -137,7 +157,7 @@
           isConst: false,
           isInitializingFormal: isInitializingFormal,
           isCovariantByDeclaration: isCovariantByDeclaration,
-          isRequired: isNamedRequired,
+          isRequired: isRequiredNamed,
           hasDeclaredInitializer: hasDeclaredInitializer,
           isLowered: isExtensionThis)
         ..fileOffset = charOffset;
@@ -145,22 +165,15 @@
     return variable!;
   }
 
-  FormalParameterBuilder clone(
+  @override
+  ParameterBuilder clone(
       List<NamedTypeBuilder> newTypes,
       SourceLibraryBuilder contextLibrary,
       TypeParameterScopeBuilder contextDeclaration) {
     // TODO(dmitryas):  It's not clear how [metadata] is used currently, and
     // how it should be cloned.  Consider cloning it instead of reusing it.
-    return new FormalParameterBuilder(
-        metadata,
-        modifiers,
-        type?.clone(newTypes, contextLibrary, contextDeclaration),
-        name,
-        parent as LibraryBuilder?,
-        charOffset,
-        fileUri: fileUri,
-        isExtensionThis: isExtensionThis)
-      ..kind = kind;
+    return new FunctionTypeParameterBuilder(metadata, kind,
+        type?.clone(newTypes, contextLibrary, contextDeclaration), name);
   }
 
   FormalParameterBuilder forFormalParameterInitializerScope() {
@@ -169,6 +182,7 @@
     if (isInitializingFormal) {
       return new FormalParameterBuilder(
           metadata,
+          kind,
           modifiers | finalMask | initializingFormalMask,
           type,
           name,
@@ -181,6 +195,7 @@
     } else if (isSuperInitializingFormal) {
       return new FormalParameterBuilder(
           metadata,
+          kind,
           modifiers | finalMask | superInitializingFormalMask,
           type,
           name,
@@ -249,3 +264,42 @@
     initializerToken = null;
   }
 }
+
+class FunctionTypeParameterBuilder implements ParameterBuilder {
+  @override
+  final List<MetadataBuilder>? metadata;
+
+  @override
+  final FormalParameterKind kind;
+
+  @override
+  final TypeBuilder? type;
+
+  @override
+  final String? name;
+
+  FunctionTypeParameterBuilder(this.metadata, this.kind, this.type, this.name);
+
+  @override
+  ParameterBuilder clone(
+      List<NamedTypeBuilder> newTypes,
+      SourceLibraryBuilder contextLibrary,
+      TypeParameterScopeBuilder contextDeclaration) {
+    // TODO(dmitryas):  It's not clear how [metadata] is used currently, and
+    // how it should be cloned.  Consider cloning it instead of reusing it.
+    return new FunctionTypeParameterBuilder(metadata, kind,
+        type?.clone(newTypes, contextLibrary, contextDeclaration), name);
+  }
+
+  @override
+  bool get isNamed => kind.isNamed;
+
+  @override
+  bool get isRequiredNamed => kind.isRequiredNamed;
+
+  @override
+  bool get isPositional => kind.isPositional;
+
+  @override
+  bool get isRequiredPositional => kind.isRequiredPositional;
+}
diff --git a/pkg/front_end/lib/src/fasta/builder/function_type_builder.dart b/pkg/front_end/lib/src/fasta/builder/function_type_builder.dart
index ea413c2..f972a4d0 100644
--- a/pkg/front_end/lib/src/fasta/builder/function_type_builder.dart
+++ b/pkg/front_end/lib/src/fasta/builder/function_type_builder.dart
@@ -27,7 +27,7 @@
 class FunctionTypeBuilder extends TypeBuilder {
   final TypeBuilder? returnType;
   final List<TypeVariableBuilder>? typeVariables;
-  final List<FormalParameterBuilder>? formals;
+  final List<ParameterBuilder>? formals;
   @override
   final NullabilityBuilder nullabilityBuilder;
   @override
@@ -67,13 +67,13 @@
     buffer.write("(");
     if (formals != null) {
       bool isFirst = true;
-      for (FormalParameterBuilder t in formals!) {
+      for (ParameterBuilder t in formals!) {
         if (!isFirst) {
           buffer.write(", ");
         } else {
           isFirst = false;
         }
-        buffer.write(t.fullNameForErrors);
+        buffer.write(t.name);
       }
     }
     buffer.write(") ->");
@@ -95,15 +95,15 @@
     List<NamedType>? namedParameters;
     int requiredParameterCount = 0;
     if (formals != null) {
-      for (FormalParameterBuilder formal in formals!) {
+      for (ParameterBuilder formal in formals!) {
         DartType type = formal.type?.build(library) ?? const DynamicType();
         if (formal.isPositional) {
           positionalParameters.add(type);
-          if (formal.isRequired) requiredParameterCount++;
+          if (formal.isRequiredPositional) requiredParameterCount++;
         } else if (formal.isNamed) {
           namedParameters ??= <NamedType>[];
-          namedParameters.add(new NamedType(formal.name, type,
-              isRequired: formal.isNamedRequired));
+          namedParameters.add(new NamedType(formal.name!, type,
+              isRequired: formal.isRequiredNamed));
         }
       }
       if (namedParameters != null) {
@@ -149,11 +149,11 @@
           typeVariables!, contextDeclaration,
           kind: TypeVariableKind.function);
     }
-    List<FormalParameterBuilder>? clonedFormals;
+    List<ParameterBuilder>? clonedFormals;
     if (formals != null) {
       clonedFormals =
-          new List<FormalParameterBuilder>.generate(formals!.length, (int i) {
-        FormalParameterBuilder formal = formals![i];
+          new List<ParameterBuilder>.generate(formals!.length, (int i) {
+        ParameterBuilder formal = formals![i];
         return formal.clone(newTypes, contextLibrary, contextDeclaration);
       }, growable: false);
     }
diff --git a/pkg/front_end/lib/src/fasta/kernel/body_builder.dart b/pkg/front_end/lib/src/fasta/kernel/body_builder.dart
index 07a3764..e4866f3 100644
--- a/pkg/front_end/lib/src/fasta/kernel/body_builder.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/body_builder.dart
@@ -1234,10 +1234,10 @@
         FormalParameterBuilder parameter = formals.parameters![i];
         Expression? initializer = parameter.variable!.initializer;
         if (!parameter.isSuperInitializingFormal &&
-            (parameter.isOptional || initializer != null)) {
+            (parameter.isOptionalPositional || initializer != null)) {
           if (!parameter.initializerWasInferred) {
             parameter.initializerWasInferred = true;
-            if (parameter.isOptional) {
+            if (parameter.isOptionalPositional) {
               initializer ??= forest.createNullLiteral(
                   // TODO(ahe): Should store: originParameter.fileOffset
                   // https://github.com/dart-lang/sdk/issues/32289
@@ -1310,7 +1310,7 @@
     if (builder.kind == ProcedureKind.Setter) {
       if (formals?.parameters == null ||
           formals!.parameters!.length != 1 ||
-          formals.parameters!.single.isOptional) {
+          formals.parameters!.single.isOptionalPositional) {
         int charOffset = formals?.charOffset ??
             body?.fileOffset ??
             builder.member.fileOffset;
@@ -1735,8 +1735,14 @@
             : new List<FormalParameterBuilder>.generate(
                 parameters.positionalParameters.length, (int i) {
                 VariableDeclaration formal = parameters.positionalParameters[i];
-                return new FormalParameterBuilder(null, 0, null, formal.name!,
-                    libraryBuilder, formal.fileOffset,
+                return new FormalParameterBuilder(
+                    /* metadata = */ null,
+                    FormalParameterKind.requiredPositional,
+                    /* modifiers = */ 0,
+                    /* type = */ null,
+                    formal.name!,
+                    libraryBuilder,
+                    formal.fileOffset,
                     fileUri: uri)
                   ..variable = formal;
               }, growable: false);
@@ -4408,7 +4414,7 @@
         return;
       }
     } else {
-      parameter = new FormalParameterBuilder(null, modifiers, type,
+      parameter = new FormalParameterBuilder(null, kind, modifiers, type,
           name?.name ?? '', libraryBuilder, offsetForToken(nameToken),
           fileUri: uri)
         ..hasDeclaredInitializer = (initializerStart != null);
@@ -4429,7 +4435,7 @@
           variable.initializer = initializer..parent = variable;
         }
       }
-    } else if (kind != FormalParameterKind.mandatory) {
+    } else if (kind != FormalParameterKind.requiredPositional) {
       variable.initializer ??= forest.createNullLiteral(noLocation)
         ..parent = variable;
     }
@@ -4450,9 +4456,6 @@
   void endOptionalFormalParameters(
       int count, Token beginToken, Token endToken) {
     debugEvent("OptionalFormalParameters");
-    FormalParameterKind kind = optional("{", beginToken)
-        ? FormalParameterKind.optionalNamed
-        : FormalParameterKind.optionalPositional;
     // When recovering from an empty list of optional arguments, count may be
     // 0. It might be simpler if the parser didn't call this method in that
     // case, however, then [beginOptionalFormalParameters] wouldn't always be
@@ -4463,9 +4466,6 @@
     if (parameters == null) {
       push(new ParserRecovery(offsetForToken(beginToken)));
     } else {
-      for (FormalParameterBuilder parameter in parameters) {
-        parameter.kind = kind;
-      }
       push(parameters);
     }
   }
@@ -7272,8 +7272,7 @@
       _validateTypeVariableUseInternal(builder.returnType,
           allowPotentiallyConstantType: allowPotentiallyConstantType);
       if (builder.formals != null) {
-        for (FormalParameterBuilder formalParameterBuilder
-            in builder.formals!) {
+        for (ParameterBuilder formalParameterBuilder in builder.formals!) {
           _validateTypeVariableUseInternal(formalParameterBuilder.type,
               allowPotentiallyConstantType: allowPotentiallyConstantType);
         }
diff --git a/pkg/front_end/lib/src/fasta/kernel/macro/macro.dart b/pkg/front_end/lib/src/fasta/kernel/macro/macro.dart
index d40c86b..4bce249 100644
--- a/pkg/front_end/lib/src/fasta/kernel/macro/macro.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/macro/macro.dart
@@ -544,7 +544,7 @@
           namedParameters.add(new macro.ParameterDeclarationImpl(
             id: macro.RemoteInstance.uniqueId,
             identifier: identifier,
-            isRequired: formal.isNamedRequired,
+            isRequired: formal.isRequiredNamed,
             isNamed: true,
             type: type,
           ));
@@ -552,7 +552,7 @@
           positionalParameters.add(new macro.ParameterDeclarationImpl(
             id: macro.RemoteInstance.uniqueId,
             identifier: identifier,
-            isRequired: formal.isRequired,
+            isRequired: formal.isRequiredPositional,
             isNamed: false,
             type: type,
           ));
diff --git a/pkg/front_end/lib/src/fasta/kernel/type_algorithms.dart b/pkg/front_end/lib/src/fasta/kernel/type_algorithms.dart
index d50d234..1992464 100644
--- a/pkg/front_end/lib/src/fasta/kernel/type_algorithms.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/type_algorithms.dart
@@ -137,7 +137,7 @@
       }
     }
     if (type.formals != null) {
-      for (FormalParameterBuilder formal in type.formals!) {
+      for (ParameterBuilder formal in type.formals!) {
         result = Variance.meet(
             result,
             Variance.combine(
@@ -281,9 +281,9 @@
       variables = new List<TypeVariableBuilder>.filled(
           type.typeVariables!.length, dummyTypeVariableBuilder);
     }
-    List<FormalParameterBuilder>? formals;
+    List<ParameterBuilder>? formals;
     if (type.formals != null) {
-      formals = new List<FormalParameterBuilder>.filled(
+      formals = new List<ParameterBuilder>.filled(
           type.formals!.length, dummyFormalParameterBuilder);
     }
     TypeBuilder? returnType;
@@ -322,7 +322,7 @@
     }
     if (type.formals != null) {
       for (int i = 0; i < formals!.length; i++) {
-        FormalParameterBuilder formal = type.formals![i];
+        ParameterBuilder formal = type.formals![i];
         TypeBuilder? parameterType = substituteRange(
             formal.type,
             functionTypeUpperSubstitution ?? upperSubstitution,
@@ -331,15 +331,8 @@
             unboundTypeVariables,
             variance: Variance.combine(variance, Variance.contravariant));
         if (parameterType != formal.type) {
-          formals[i] = new FormalParameterBuilder(
-              formal.metadata,
-              formal.modifiers,
-              parameterType,
-              formal.name,
-              formal.parent as LibraryBuilder?,
-              formal.charOffset,
-              fileUri: formal.fileUri,
-              isExtensionThis: formal.isExtensionThis);
+          formals[i] = new FunctionTypeParameterBuilder(
+              formal.metadata, formal.kind, parameterType, formal.name);
           changed = true;
         } else {
           formals[i] = formal;
@@ -476,7 +469,7 @@
           }
         }
         if (type.formals != null) {
-          for (FormalParameterBuilder parameter in type.formals!) {
+          for (ParameterBuilder parameter in type.formals!) {
             collectReferencesFrom(index, parameter.type);
           }
         }
@@ -530,7 +523,7 @@
       }
     }
     if (type.formals != null) {
-      for (FormalParameterBuilder formal in type.formals!) {
+      for (ParameterBuilder formal in type.formals!) {
         uses.addAll(findVariableUsesInType(variable, formal.type));
       }
     }
@@ -651,7 +644,7 @@
       }
     }
     if (type.formals != null) {
-      for (FormalParameterBuilder formal in type.formals!) {
+      for (ParameterBuilder formal in type.formals!) {
         typesAndDependencies
             .addAll(findRawTypesWithInboundReferences(formal.type));
       }
@@ -822,7 +815,7 @@
       }
     }
     if (start.formals != null) {
-      for (FormalParameterBuilder formal in start.formals!) {
+      for (ParameterBuilder formal in start.formals!) {
         paths.addAll(findRawTypePathsToDeclaration(formal.type, end, visited));
       }
     }
@@ -1030,7 +1023,7 @@
     }
     findUnaliasedGenericFunctionTypes(type.returnType, result: result);
     if (type.formals != null) {
-      for (FormalParameterBuilder formal in type.formals!) {
+      for (ParameterBuilder formal in type.formals!) {
         findUnaliasedGenericFunctionTypes(formal.type, result: result);
       }
     }
@@ -1059,7 +1052,7 @@
     }
     findGenericFunctionTypes(type.returnType, result: result);
     if (type.formals != null) {
-      for (FormalParameterBuilder formal in type.formals!) {
+      for (ParameterBuilder formal in type.formals!) {
         findGenericFunctionTypes(formal.type, result: result);
       }
     }
diff --git a/pkg/front_end/lib/src/fasta/kernel/type_builder_computer.dart b/pkg/front_end/lib/src/fasta/kernel/type_builder_computer.dart
index 591ae4d..d21a6c7 100644
--- a/pkg/front_end/lib/src/fasta/kernel/type_builder_computer.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/type_builder_computer.dart
@@ -127,36 +127,27 @@
     List<TypeVariableBuilder>? typeVariables = null;
     List<DartType> positionalParameters = node.positionalParameters;
     List<NamedType> namedParameters = node.namedParameters;
-    List<FormalParameterBuilder> formals =
-        new List<FormalParameterBuilder>.filled(
-            positionalParameters.length + namedParameters.length,
-            dummyFormalParameterBuilder);
+    List<ParameterBuilder> formals = new List<ParameterBuilder>.filled(
+        positionalParameters.length + namedParameters.length,
+        dummyFormalParameterBuilder);
     for (int i = 0; i < positionalParameters.length; i++) {
       TypeBuilder type = positionalParameters[i].accept(this);
-      FormalParameterKind kind = FormalParameterKind.mandatory;
+      FormalParameterKind kind = FormalParameterKind.requiredPositional;
       if (i >= node.requiredParameterCount) {
         kind = FormalParameterKind.optionalPositional;
       }
-      formals[i] = new FormalParameterBuilder(
-          /* metadata = */ null,
-          /* modifiers = */ 0,
-          type,
-          /* name = */ '',
-          /* compilationUnit = */ null,
-          /* charOffset = */ TreeNode.noOffset)
-        ..kind = kind;
+      formals[i] = new FunctionTypeParameterBuilder(
+          /* metadata = */ null, kind, type, /* name = */ null);
     }
     for (int i = 0; i < namedParameters.length; i++) {
       NamedType parameter = namedParameters[i];
       TypeBuilder type = parameter.type.accept(this);
-      formals[i + positionalParameters.length] = new FormalParameterBuilder(
-          /* metadata = */ null,
-          /* modifiers = */ 0,
-          type,
-          parameter.name,
-          /* compilationUnit = */ null,
-          /* charOffset = */ TreeNode.noOffset)
-        ..kind = FormalParameterKind.optionalNamed;
+      FormalParameterKind kind = parameter.isRequired
+          ? FormalParameterKind.requiredNamed
+          : FormalParameterKind.optionalNamed;
+      formals[i + positionalParameters.length] =
+          new FunctionTypeParameterBuilder(
+              /* metadata = */ null, kind, type, parameter.name);
     }
     return new FunctionTypeBuilder(
         returnType,
diff --git a/pkg/front_end/lib/src/fasta/kernel/utils.dart b/pkg/front_end/lib/src/fasta/kernel/utils.dart
index fbed0bd..3443cf7 100644
--- a/pkg/front_end/lib/src/fasta/kernel/utils.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/utils.dart
@@ -6,6 +6,7 @@
 
 import 'dart:typed_data' show Uint8List;
 
+import 'package:_fe_analyzer_shared/src/parser/formal_parameter_kind.dart';
 import 'package:_fe_analyzer_shared/src/scanner/scanner.dart' show Token;
 import 'package:_fe_analyzer_shared/src/scanner/token.dart'
     show SyntheticToken, TokenType;
@@ -231,7 +232,9 @@
 final TypeBuilder dummyTypeBuilder =
     new FixedTypeBuilder(dummyDartType, dummyUri, -1);
 final FormalParameterBuilder dummyFormalParameterBuilder =
-    new FormalParameterBuilder(null, 0, null, '', null, -1, fileUri: dummyUri);
+    new FormalParameterBuilder(
+        null, FormalParameterKind.requiredPositional, 0, null, '', null, -1,
+        fileUri: dummyUri);
 final TypeVariableBuilder dummyTypeVariableBuilder = new TypeVariableBuilder(
     TypeVariableBuilder.noNameSentinel, null, -1, null,
     kind: TypeVariableKind.function);
diff --git a/pkg/front_end/lib/src/fasta/source/diet_listener.dart b/pkg/front_end/lib/src/fasta/source/diet_listener.dart
index 5bbfd4a..2d46643 100644
--- a/pkg/front_end/lib/src/fasta/source/diet_listener.dart
+++ b/pkg/front_end/lib/src/fasta/source/diet_listener.dart
@@ -289,10 +289,10 @@
     if (typedefBuilder is TypeAliasBuilder) {
       TypeBuilder? type = typedefBuilder.type;
       if (type is FunctionTypeBuilder) {
-        List<FormalParameterBuilder>? formals = type.formals;
+        List<ParameterBuilder>? formals = type.formals;
         if (formals != null) {
           for (int i = 0; i < formals.length; ++i) {
-            FormalParameterBuilder formal = formals[i];
+            ParameterBuilder formal = formals[i];
             List<MetadataBuilder>? metadata = formal.metadata;
             if (metadata != null && metadata.length > 0) {
               // [parseMetadata] is using [Parser.parseMetadataStar] under the
diff --git a/pkg/front_end/lib/src/fasta/source/outline_builder.dart b/pkg/front_end/lib/src/fasta/source/outline_builder.dart
index 1e5c1d6..c9b3083 100644
--- a/pkg/front_end/lib/src/fasta/source/outline_builder.dart
+++ b/pkg/front_end/lib/src/fasta/source/outline_builder.dart
@@ -1797,7 +1797,7 @@
       } else {
         if (formals != null) {
           for (FormalParameterBuilder formal in formals) {
-            if (!formal.isRequired) {
+            if (!formal.isRequiredPositional) {
               addProblem(messageOperatorWithOptionalFormals, formal.charOffset,
                   formal.name.length);
             }
@@ -1920,8 +1920,15 @@
           libraryBuilder.unboundTypeVariables.addAll(unboundTypeVariables);
         }
         synthesizedFormals.add(new FormalParameterBuilder(
-            null, finalMask, thisType, extensionThisName, null, charOffset,
-            fileUri: uri, isExtensionThis: true));
+            /* metadata = */ null,
+            FormalParameterKind.requiredPositional,
+            finalMask,
+            thisType,
+            extensionThisName,
+            null,
+            charOffset,
+            fileUri: uri,
+            isExtensionThis: true));
         if (formals != null) {
           synthesizedFormals.addAll(formals);
         }
@@ -2284,6 +2291,7 @@
     } else {
       push(libraryBuilder.addFormalParameter(
           metadata,
+          kind,
           modifiers,
           type,
           name == null ? FormalParameterBuilder.noNameSentinel : name as String,
@@ -2321,9 +2329,6 @@
   void endOptionalFormalParameters(
       int count, Token beginToken, Token endToken) {
     debugEvent("OptionalFormalParameters");
-    FormalParameterKind kind = optional("{", beginToken)
-        ? FormalParameterKind.optionalNamed
-        : FormalParameterKind.optionalPositional;
     // When recovering from an empty list of optional arguments, count may be
     // 0. It might be simpler if the parser didn't call this method in that
     // case, however, then [beginOptionalFormalParameters] wouldn't always be
@@ -2334,9 +2339,6 @@
     if (parameters == null) {
       push(new ParserRecovery(offsetForToken(beginToken)));
     } else {
-      for (FormalParameterBuilder parameter in parameters) {
-        parameter.kind = kind;
-      }
       push(parameters);
     }
   }
diff --git a/pkg/front_end/lib/src/fasta/source/source_constructor_builder.dart b/pkg/front_end/lib/src/fasta/source/source_constructor_builder.dart
index 25777e5..52e657e 100644
--- a/pkg/front_end/lib/src/fasta/source/source_constructor_builder.dart
+++ b/pkg/front_end/lib/src/fasta/source/source_constructor_builder.dart
@@ -428,7 +428,8 @@
                     superInitializingFormalIndex];
             correspondingSuperFormalType =
                 positionalSuperFormalType[superInitializingFormalIndex];
-            if (!hasImmediatelyDeclaredInitializer && !formal.isRequired) {
+            if (!hasImmediatelyDeclaredInitializer &&
+                !formal.isRequiredPositional) {
               (positionalSuperParameters ??= <int?>[]).add(formalIndex);
             } else {
               (positionalSuperParameters ??= <int?>[]).add(null);
@@ -441,7 +442,7 @@
             formal.hasDeclaredInitializer = hasImmediatelyDeclaredInitializer ||
                 namedSuperFormalHasInitializer[formal.name]!;
             correspondingSuperFormalType = namedSuperFormalType[formal.name];
-            if (!hasImmediatelyDeclaredInitializer && !formal.isNamedRequired) {
+            if (!hasImmediatelyDeclaredInitializer && !formal.isRequiredNamed) {
               (namedSuperParameters ??= <String>[]).add(formal.name);
             }
           } else {
diff --git a/pkg/front_end/lib/src/fasta/source/source_enum_builder.dart b/pkg/front_end/lib/src/fasta/source/source_enum_builder.dart
index de8d674..4d57b10 100644
--- a/pkg/front_end/lib/src/fasta/source/source_enum_builder.dart
+++ b/pkg/front_end/lib/src/fasta/source/source_enum_builder.dart
@@ -4,6 +4,7 @@
 
 library fasta.enum_builder;
 
+import 'package:_fe_analyzer_shared/src/parser/formal_parameter_kind.dart';
 import 'package:_fe_analyzer_shared/src/scanner/token.dart';
 
 import 'package:kernel/ast.dart';
@@ -310,9 +311,21 @@
               /* typeParameters = */ null,
               <FormalParameterBuilder>[
                 new FormalParameterBuilder(
-                    null, 0, intType, "index", libraryBuilder, charOffset),
+                    null,
+                    FormalParameterKind.requiredPositional,
+                    0,
+                    intType,
+                    "index",
+                    libraryBuilder,
+                    charOffset),
                 new FormalParameterBuilder(
-                    null, 0, stringType, "name", libraryBuilder, charOffset)
+                    null,
+                    FormalParameterKind.requiredPositional,
+                    0,
+                    stringType,
+                    "name",
+                    libraryBuilder,
+                    charOffset)
               ],
               libraryBuilder,
               charOffset,
@@ -332,11 +345,23 @@
           member.formals!.insert(
               0,
               new FormalParameterBuilder(
-                  null, 0, stringType, "name", libraryBuilder, charOffset));
+                  /* metadata = */ null,
+                  FormalParameterKind.requiredPositional,
+                  /* modifiers = */ 0,
+                  stringType,
+                  "name",
+                  libraryBuilder,
+                  charOffset));
           member.formals!.insert(
               0,
               new FormalParameterBuilder(
-                  null, 0, intType, "index", libraryBuilder, charOffset));
+                  /* metadata = */ null,
+                  FormalParameterKind.requiredPositional,
+                  /* modifiers = */ 0,
+                  intType,
+                  "index",
+                  libraryBuilder,
+                  charOffset));
         }
       });
     }
diff --git a/pkg/front_end/lib/src/fasta/source/source_function_builder.dart b/pkg/front_end/lib/src/fasta/source/source_function_builder.dart
index 1f34e7d..1411267 100644
--- a/pkg/front_end/lib/src/fasta/source/source_function_builder.dart
+++ b/pkg/front_end/lib/src/fasta/source/source_function_builder.dart
@@ -355,13 +355,13 @@
           function.positionalParameters.add(parameter);
         }
         parameter.parent = function;
-        if (formal.isRequired) {
+        if (formal.isRequiredPositional) {
           function.requiredParameterCount++;
         }
 
         if (libraryBuilder.isNonNullableByDefault) {
           // Required named parameters can't have default values.
-          if (formal.isNamedRequired && formal.initializerToken != null) {
+          if (formal.isRequiredNamed && formal.initializerToken != null) {
             libraryBuilder.addProblem(
                 templateRequiredNamedParameterHasDefaultValueError
                     .withArguments(formal.name),
@@ -374,7 +374,7 @@
     }
     if (!isExtensionInstanceMember &&
         isSetter &&
-        (formals?.length != 1 || formals![0].isOptional)) {
+        (formals?.length != 1 || formals![0].isOptionalPositional)) {
       // Replace illegal parameters by single dummy parameter.
       // Do this after building the parameters, since the diet listener
       // assumes that parameters are built, even if illegal in number.
diff --git a/pkg/front_end/lib/src/fasta/source/source_library_builder.dart b/pkg/front_end/lib/src/fasta/source/source_library_builder.dart
index 9b796de..72c27c2 100644
--- a/pkg/front_end/lib/src/fasta/source/source_library_builder.dart
+++ b/pkg/front_end/lib/src/fasta/source/source_library_builder.dart
@@ -7,6 +7,7 @@
 import 'dart:collection';
 import 'dart:convert' show jsonEncode;
 
+import 'package:_fe_analyzer_shared/src/parser/formal_parameter_kind.dart';
 import 'package:_fe_analyzer_shared/src/scanner/token.dart' show Token;
 import 'package:_fe_analyzer_shared/src/util/resolve_relative_uri.dart'
     show resolveRelativeUri;
@@ -2264,7 +2265,7 @@
           }
         } else if (type is FunctionTypeBuilder) {
           if (type.formals != null) {
-            for (FormalParameterBuilder formal in type.formals!) {
+            for (ParameterBuilder formal in type.formals!) {
               if (usesTypeVariables(formal.type)) {
                 return true;
               }
@@ -3014,6 +3015,7 @@
 
   FormalParameterBuilder addFormalParameter(
       List<MetadataBuilder>? metadata,
+      FormalParameterKind kind,
       int modifiers,
       TypeBuilder? type,
       String name,
@@ -3030,7 +3032,7 @@
       modifiers |= superInitializingFormalMask;
     }
     FormalParameterBuilder formal = new FormalParameterBuilder(
-        metadata, modifiers, type, name, this, charOffset,
+        metadata, kind, modifiers, type, name, this, charOffset,
         fileUri: fileUri)
       ..initializerToken = initializerToken
       ..hasDeclaredInitializer = (initializerToken != null);
@@ -4176,8 +4178,9 @@
     if (!isNonNullableByDefault) return;
 
     for (FormalParameterBuilder formal in formals) {
-      bool isOptionalPositional = formal.isOptional && formal.isPositional;
-      bool isOptionalNamed = !formal.isNamedRequired && formal.isNamed;
+      bool isOptionalPositional =
+          formal.isOptionalPositional && formal.isPositional;
+      bool isOptionalNamed = !formal.isRequiredNamed && formal.isNamed;
       bool isOptional = isOptionalPositional || isOptionalNamed;
       if (isOptional &&
           formal.variable!.type.isPotentiallyNonNullable &&
@@ -5455,7 +5458,7 @@
     }
     if (root.formals != null && root.formals!.isNotEmpty) {
       internalDependents = <TypeBuilder>[];
-      for (FormalParameterBuilder formal in root.formals!) {
+      for (ParameterBuilder formal in root.formals!) {
         internalDependents.add(formal.type!);
       }
     }
diff --git a/pkg/front_end/parser_testcases/augmentation/member_declarations.dart.expect b/pkg/front_end/parser_testcases/augmentation/member_declarations.dart.expect
index 91c611c..8f1c122 100644
--- a/pkg/front_end/parser_testcases/augmentation/member_declarations.dart.expect
+++ b/pkg/front_end/parser_testcases/augmentation/member_declarations.dart.expect
@@ -85,7 +85,7 @@
                 handleNoType(()
                 handleIdentifier(value, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -107,7 +107,7 @@
                 handleNoType(()
                 handleIdentifier(value, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -260,7 +260,7 @@
                 handleNoType(()
                 handleIdentifier(value, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.StaticMethod)
+              endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.StaticMethod)
             endFormalParameters(1, (, ), MemberKind.StaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -282,7 +282,7 @@
                 handleNoType(()
                 handleIdentifier(value, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.StaticMethod)
+              endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.StaticMethod)
             endFormalParameters(1, (, ), MemberKind.StaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -448,7 +448,7 @@
                 handleNoType(()
                 handleIdentifier(value, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -470,7 +470,7 @@
                 handleNoType(()
                 handleIdentifier(value, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -623,7 +623,7 @@
                 handleNoType(()
                 handleIdentifier(value, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.StaticMethod)
+              endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.StaticMethod)
             endFormalParameters(1, (, ), MemberKind.StaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -645,7 +645,7 @@
                 handleNoType(()
                 handleIdentifier(value, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.StaticMethod)
+              endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.StaticMethod)
             endFormalParameters(1, (, ), MemberKind.StaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/augmentation/member_declarations.dart.intertwined.expect b/pkg/front_end/parser_testcases/augmentation/member_declarations.dart.intertwined.expect
index 7f35186..4865006 100644
--- a/pkg/front_end/parser_testcases/augmentation/member_declarations.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/augmentation/member_declarations.dart.intertwined.expect
@@ -177,7 +177,7 @@
                   parseFormalParameters(setter, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(value)
                           listener: endMetadataStar(0)
@@ -186,7 +186,7 @@
                         ensureIdentifier((, formalParameterDeclaration)
                           listener: handleIdentifier(value, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -218,7 +218,7 @@
                   parseFormalParameters(setter, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(value)
                           listener: endMetadataStar(0)
@@ -227,7 +227,7 @@
                         ensureIdentifier((, formalParameterDeclaration)
                           listener: handleIdentifier(value, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -513,7 +513,7 @@
                   parseFormalParameters(setter, MemberKind.StaticMethod)
                     parseFormalParametersRest((, MemberKind.StaticMethod)
                       listener: beginFormalParameters((, MemberKind.StaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.StaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.StaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(value)
                           listener: endMetadataStar(0)
@@ -522,7 +522,7 @@
                         ensureIdentifier((, formalParameterDeclaration)
                           listener: handleIdentifier(value, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.StaticMethod)
+                        listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.StaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.StaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -553,7 +553,7 @@
                   parseFormalParameters(setter, MemberKind.StaticMethod)
                     parseFormalParametersRest((, MemberKind.StaticMethod)
                       listener: beginFormalParameters((, MemberKind.StaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.StaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.StaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(value)
                           listener: endMetadataStar(0)
@@ -562,7 +562,7 @@
                         ensureIdentifier((, formalParameterDeclaration)
                           listener: handleIdentifier(value, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.StaticMethod)
+                        listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.StaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.StaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -874,7 +874,7 @@
                 parseFormalParameters(setter, MemberKind.NonStaticMethod)
                   parseFormalParametersRest((, MemberKind.NonStaticMethod)
                     listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                    parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                    parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       parseMetadataStar(()
                         listener: beginMetadataStar(value)
                         listener: endMetadataStar(0)
@@ -883,7 +883,7 @@
                       ensureIdentifier((, formalParameterDeclaration)
                         listener: handleIdentifier(value, formalParameterDeclaration)
                       listener: handleFormalParameterWithoutValue())
-                      listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                     listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
               parseInitializersOpt())
                 listener: handleNoInitializers()
@@ -915,7 +915,7 @@
                 parseFormalParameters(setter, MemberKind.NonStaticMethod)
                   parseFormalParametersRest((, MemberKind.NonStaticMethod)
                     listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                    parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                    parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       parseMetadataStar(()
                         listener: beginMetadataStar(value)
                         listener: endMetadataStar(0)
@@ -924,7 +924,7 @@
                       ensureIdentifier((, formalParameterDeclaration)
                         listener: handleIdentifier(value, formalParameterDeclaration)
                       listener: handleFormalParameterWithoutValue())
-                      listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                     listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
               parseInitializersOpt())
                 listener: handleNoInitializers()
@@ -1210,7 +1210,7 @@
                 parseFormalParameters(setter, MemberKind.StaticMethod)
                   parseFormalParametersRest((, MemberKind.StaticMethod)
                     listener: beginFormalParameters((, MemberKind.StaticMethod)
-                    parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.StaticMethod)
+                    parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.StaticMethod)
                       parseMetadataStar(()
                         listener: beginMetadataStar(value)
                         listener: endMetadataStar(0)
@@ -1219,7 +1219,7 @@
                       ensureIdentifier((, formalParameterDeclaration)
                         listener: handleIdentifier(value, formalParameterDeclaration)
                       listener: handleFormalParameterWithoutValue())
-                      listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.StaticMethod)
+                      listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.StaticMethod)
                     listener: endFormalParameters(1, (, ), MemberKind.StaticMethod)
               parseInitializersOpt())
                 listener: handleNoInitializers()
@@ -1250,7 +1250,7 @@
                 parseFormalParameters(setter, MemberKind.StaticMethod)
                   parseFormalParametersRest((, MemberKind.StaticMethod)
                     listener: beginFormalParameters((, MemberKind.StaticMethod)
-                    parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.StaticMethod)
+                    parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.StaticMethod)
                       parseMetadataStar(()
                         listener: beginMetadataStar(value)
                         listener: endMetadataStar(0)
@@ -1259,7 +1259,7 @@
                       ensureIdentifier((, formalParameterDeclaration)
                         listener: handleIdentifier(value, formalParameterDeclaration)
                       listener: handleFormalParameterWithoutValue())
-                      listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.StaticMethod)
+                      listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.StaticMethod)
                     listener: endFormalParameters(1, (, ), MemberKind.StaticMethod)
               parseInitializersOpt())
                 listener: handleNoInitializers()
diff --git a/pkg/front_end/parser_testcases/augmentation/member_errors.dart.expect b/pkg/front_end/parser_testcases/augmentation/member_errors.dart.expect
index 693edbe..d550bda 100644
--- a/pkg/front_end/parser_testcases/augmentation/member_errors.dart.expect
+++ b/pkg/front_end/parser_testcases/augmentation/member_errors.dart.expect
@@ -456,7 +456,7 @@
                 handleNoType(()
                 handleIdentifier(value, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -479,7 +479,7 @@
                 handleNoType(()
                 handleIdentifier(value, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -501,7 +501,7 @@
                 handleNoType(()
                 handleIdentifier(value, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -523,7 +523,7 @@
                 handleNoType(()
                 handleIdentifier(value, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -546,7 +546,7 @@
                 handleNoType(()
                 handleIdentifier(value, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -568,7 +568,7 @@
                 handleNoType(()
                 handleIdentifier(value, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -940,7 +940,7 @@
                 handleNoType(()
                 handleIdentifier(value, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.StaticMethod)
+              endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.StaticMethod)
             endFormalParameters(1, (, ), MemberKind.StaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -963,7 +963,7 @@
                 handleNoType(()
                 handleIdentifier(value, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.StaticMethod)
+              endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.StaticMethod)
             endFormalParameters(1, (, ), MemberKind.StaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -986,7 +986,7 @@
                 handleNoType(()
                 handleIdentifier(value, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.StaticMethod)
+              endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.StaticMethod)
             endFormalParameters(1, (, ), MemberKind.StaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -1009,7 +1009,7 @@
                 handleNoType(()
                 handleIdentifier(value, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.StaticMethod)
+              endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.StaticMethod)
             endFormalParameters(1, (, ), MemberKind.StaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/augmentation/member_errors.dart.intertwined.expect b/pkg/front_end/parser_testcases/augmentation/member_errors.dart.intertwined.expect
index 01ea526..03c4dfb 100644
--- a/pkg/front_end/parser_testcases/augmentation/member_errors.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/augmentation/member_errors.dart.intertwined.expect
@@ -429,7 +429,7 @@
                   parseFormalParameters(setter, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(value)
                           listener: endMetadataStar(0)
@@ -438,7 +438,7 @@
                         ensureIdentifier((, formalParameterDeclaration)
                           listener: handleIdentifier(value, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -472,7 +472,7 @@
                   parseFormalParameters(setter, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(value)
                           listener: endMetadataStar(0)
@@ -481,7 +481,7 @@
                         ensureIdentifier((, formalParameterDeclaration)
                           listener: handleIdentifier(value, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -513,7 +513,7 @@
                   parseFormalParameters(setter, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(value)
                           listener: endMetadataStar(0)
@@ -522,7 +522,7 @@
                         ensureIdentifier((, formalParameterDeclaration)
                           listener: handleIdentifier(value, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -554,7 +554,7 @@
                   parseFormalParameters(setter, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(value)
                           listener: endMetadataStar(0)
@@ -563,7 +563,7 @@
                         ensureIdentifier((, formalParameterDeclaration)
                           listener: handleIdentifier(value, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -597,7 +597,7 @@
                   parseFormalParameters(setter, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(value)
                           listener: endMetadataStar(0)
@@ -606,7 +606,7 @@
                         ensureIdentifier((, formalParameterDeclaration)
                           listener: handleIdentifier(value, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -638,7 +638,7 @@
                   parseFormalParameters(setter, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(value)
                           listener: endMetadataStar(0)
@@ -647,7 +647,7 @@
                         ensureIdentifier((, formalParameterDeclaration)
                           listener: handleIdentifier(value, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -1332,7 +1332,7 @@
                   parseFormalParameters(setter, MemberKind.StaticMethod)
                     parseFormalParametersRest((, MemberKind.StaticMethod)
                       listener: beginFormalParameters((, MemberKind.StaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.StaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.StaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(value)
                           listener: endMetadataStar(0)
@@ -1341,7 +1341,7 @@
                         ensureIdentifier((, formalParameterDeclaration)
                           listener: handleIdentifier(value, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.StaticMethod)
+                        listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.StaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.StaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -1374,7 +1374,7 @@
                   parseFormalParameters(setter, MemberKind.StaticMethod)
                     parseFormalParametersRest((, MemberKind.StaticMethod)
                       listener: beginFormalParameters((, MemberKind.StaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.StaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.StaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(value)
                           listener: endMetadataStar(0)
@@ -1383,7 +1383,7 @@
                         ensureIdentifier((, formalParameterDeclaration)
                           listener: handleIdentifier(value, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.StaticMethod)
+                        listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.StaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.StaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -1416,7 +1416,7 @@
                   parseFormalParameters(setter, MemberKind.StaticMethod)
                     parseFormalParametersRest((, MemberKind.StaticMethod)
                       listener: beginFormalParameters((, MemberKind.StaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.StaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.StaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(value)
                           listener: endMetadataStar(0)
@@ -1425,7 +1425,7 @@
                         ensureIdentifier((, formalParameterDeclaration)
                           listener: handleIdentifier(value, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.StaticMethod)
+                        listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.StaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.StaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -1458,7 +1458,7 @@
                   parseFormalParameters(setter, MemberKind.StaticMethod)
                     parseFormalParametersRest((, MemberKind.StaticMethod)
                       listener: beginFormalParameters((, MemberKind.StaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.StaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.StaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(value)
                           listener: endMetadataStar(0)
@@ -1467,7 +1467,7 @@
                         ensureIdentifier((, formalParameterDeclaration)
                           listener: handleIdentifier(value, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.StaticMethod)
+                        listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.StaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.StaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
diff --git a/pkg/front_end/parser_testcases/augmentation/top_level_declarations.dart.expect b/pkg/front_end/parser_testcases/augmentation/top_level_declarations.dart.expect
index ff03f5c..b0493a0 100644
--- a/pkg/front_end/parser_testcases/augmentation/top_level_declarations.dart.expect
+++ b/pkg/front_end/parser_testcases/augmentation/top_level_declarations.dart.expect
@@ -69,7 +69,7 @@
           handleNoType(()
           handleIdentifier(value, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -90,7 +90,7 @@
           handleNoType(()
           handleIdentifier(value, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/augmentation/top_level_declarations.dart.intertwined.expect b/pkg/front_end/parser_testcases/augmentation/top_level_declarations.dart.intertwined.expect
index 3bc9178..4e04f8b 100644
--- a/pkg/front_end/parser_testcases/augmentation/top_level_declarations.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/augmentation/top_level_declarations.dart.intertwined.expect
@@ -139,7 +139,7 @@
           parseFormalParameters(setter, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(value)
                   listener: endMetadataStar(0)
@@ -148,7 +148,7 @@
                 ensureIdentifier((, formalParameterDeclaration)
                   listener: handleIdentifier(value, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -176,7 +176,7 @@
           parseFormalParameters(setter, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(value)
                   listener: endMetadataStar(0)
@@ -185,7 +185,7 @@
                 ensureIdentifier((, formalParameterDeclaration)
                   listener: handleIdentifier(value, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/augmentation/top_level_errors.dart.expect b/pkg/front_end/parser_testcases/augmentation/top_level_errors.dart.expect
index e6b0821..6262504 100644
--- a/pkg/front_end/parser_testcases/augmentation/top_level_errors.dart.expect
+++ b/pkg/front_end/parser_testcases/augmentation/top_level_errors.dart.expect
@@ -304,7 +304,7 @@
           handleNoType(()
           handleIdentifier(value, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -326,7 +326,7 @@
           handleNoType(()
           handleIdentifier(value, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       handleEmptyFunctionBody(;)
@@ -347,7 +347,7 @@
           handleNoType(()
           handleIdentifier(value, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       handleEmptyFunctionBody(;)
@@ -368,7 +368,7 @@
           handleNoType(()
           handleIdentifier(value, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -390,7 +390,7 @@
           handleNoType(()
           handleIdentifier(value, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       handleEmptyFunctionBody(;)
@@ -411,7 +411,7 @@
           handleNoType(()
           handleIdentifier(value, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       handleEmptyFunctionBody(;)
diff --git a/pkg/front_end/parser_testcases/augmentation/top_level_errors.dart.intertwined.expect b/pkg/front_end/parser_testcases/augmentation/top_level_errors.dart.intertwined.expect
index a5272f9..fef31b5 100644
--- a/pkg/front_end/parser_testcases/augmentation/top_level_errors.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/augmentation/top_level_errors.dart.intertwined.expect
@@ -361,7 +361,7 @@
           parseFormalParameters(setter, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(value)
                   listener: endMetadataStar(0)
@@ -370,7 +370,7 @@
                 ensureIdentifier((, formalParameterDeclaration)
                   listener: handleIdentifier(value, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -401,7 +401,7 @@
           parseFormalParameters(setter, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(value)
                   listener: endMetadataStar(0)
@@ -410,7 +410,7 @@
                 ensureIdentifier((, formalParameterDeclaration)
                   listener: handleIdentifier(value, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -439,7 +439,7 @@
           parseFormalParameters(setter, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(value)
                   listener: endMetadataStar(0)
@@ -448,7 +448,7 @@
                 ensureIdentifier((, formalParameterDeclaration)
                   listener: handleIdentifier(value, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -476,7 +476,7 @@
           parseFormalParameters(setter, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(value)
                   listener: endMetadataStar(0)
@@ -485,7 +485,7 @@
                 ensureIdentifier((, formalParameterDeclaration)
                   listener: handleIdentifier(value, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -515,7 +515,7 @@
           parseFormalParameters(setter, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(value)
                   listener: endMetadataStar(0)
@@ -524,7 +524,7 @@
                 ensureIdentifier((, formalParameterDeclaration)
                   listener: handleIdentifier(value, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -552,7 +552,7 @@
           parseFormalParameters(setter, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(value)
                   listener: endMetadataStar(0)
@@ -561,7 +561,7 @@
                 ensureIdentifier((, formalParameterDeclaration)
                   listener: handleIdentifier(value, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/enhanced_enums/entries_with_type_arguments.dart.expect b/pkg/front_end/parser_testcases/enhanced_enums/entries_with_type_arguments.dart.expect
index 92d5054..192dfcf 100644
--- a/pkg/front_end/parser_testcases/enhanced_enums/entries_with_type_arguments.dart.expect
+++ b/pkg/front_end/parser_testcases/enhanced_enums/entries_with_type_arguments.dart.expect
@@ -110,7 +110,7 @@
               handleType(int, null)
               handleIdentifier(value, formalParameterDeclaration)
               handleFormalParameterWithoutValue())
-            endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+            endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
           endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
           handleNoInitializers()
           handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/enhanced_enums/entries_with_type_arguments.dart.intertwined.expect b/pkg/front_end/parser_testcases/enhanced_enums/entries_with_type_arguments.dart.intertwined.expect
index 6ea8819..f2e1124 100644
--- a/pkg/front_end/parser_testcases/enhanced_enums/entries_with_type_arguments.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/enhanced_enums/entries_with_type_arguments.dart.intertwined.expect
@@ -165,7 +165,7 @@
               parseFormalParameters(named, MemberKind.NonStaticMethod)
                 parseFormalParametersRest((, MemberKind.NonStaticMethod)
                   listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                  parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                  parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                     parseMetadataStar(()
                       listener: beginMetadataStar(int)
                       listener: endMetadataStar(0)
@@ -176,7 +176,7 @@
                     ensureIdentifier(int, formalParameterDeclaration)
                       listener: handleIdentifier(value, formalParameterDeclaration)
                     listener: handleFormalParameterWithoutValue())
-                    listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                    listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                   listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             parseInitializersOpt())
               listener: handleNoInitializers()
diff --git a/pkg/front_end/parser_testcases/error_recovery/extension_member_contributor_test_completion.dart.expect b/pkg/front_end/parser_testcases/error_recovery/extension_member_contributor_test_completion.dart.expect
index 3fd8b9b..19c202d 100644
--- a/pkg/front_end/parser_testcases/error_recovery/extension_member_contributor_test_completion.dart.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/extension_member_contributor_test_completion.dart.expect
@@ -51,7 +51,7 @@
                 handleType(int, null)
                 handleIdentifier(b, formalParameterDeclaration)
                 handleFormalParameterWithoutValue(,)
-              endFormalParameter(null, null, null, b, null, null, FormalParameterKind.mandatory, MemberKind.ExtensionNonStaticMethod)
+              endFormalParameter(null, null, null, b, null, null, FormalParameterKind.requiredPositional, MemberKind.ExtensionNonStaticMethod)
               beginMetadataStar(int)
               endMetadataStar(0)
               beginFormalParameter(int, MemberKind.ExtensionNonStaticMethod, null, null, null)
@@ -60,7 +60,7 @@
                 handleType(int, null)
                 handleIdentifier(c, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, c, null, null, FormalParameterKind.mandatory, MemberKind.ExtensionNonStaticMethod)
+              endFormalParameter(null, null, null, c, null, null, FormalParameterKind.requiredPositional, MemberKind.ExtensionNonStaticMethod)
             endFormalParameters(2, (, ), MemberKind.ExtensionNonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -100,7 +100,7 @@
                 handleType(int, null)
                 handleIdentifier(d, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, d, null, null, FormalParameterKind.mandatory, MemberKind.ExtensionNonStaticMethod)
+              endFormalParameter(null, null, null, d, null, null, FormalParameterKind.requiredPositional, MemberKind.ExtensionNonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.ExtensionNonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -131,7 +131,7 @@
           handleType(List, null)
           handleIdentifier(l, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, l, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, l, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -169,7 +169,7 @@
           handleType(List, null)
           handleIdentifier(l, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, l, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, l, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/error_recovery/extension_member_contributor_test_completion.dart.intertwined.expect b/pkg/front_end/parser_testcases/error_recovery/extension_member_contributor_test_completion.dart.intertwined.expect
index 334068a..bdae2a2 100644
--- a/pkg/front_end/parser_testcases/error_recovery/extension_member_contributor_test_completion.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/extension_member_contributor_test_completion.dart.intertwined.expect
@@ -53,7 +53,7 @@
                 parseFormalParameters(a, MemberKind.ExtensionNonStaticMethod)
                   parseFormalParametersRest((, MemberKind.ExtensionNonStaticMethod)
                     listener: beginFormalParameters((, MemberKind.ExtensionNonStaticMethod)
-                    parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.ExtensionNonStaticMethod)
+                    parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.ExtensionNonStaticMethod)
                       parseMetadataStar(()
                         listener: beginMetadataStar(int)
                         listener: endMetadataStar(0)
@@ -64,8 +64,8 @@
                       ensureIdentifier(int, formalParameterDeclaration)
                         listener: handleIdentifier(b, formalParameterDeclaration)
                       listener: handleFormalParameterWithoutValue(,)
-                      listener: endFormalParameter(null, null, null, b, null, null, FormalParameterKind.mandatory, MemberKind.ExtensionNonStaticMethod)
-                    parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.ExtensionNonStaticMethod)
+                      listener: endFormalParameter(null, null, null, b, null, null, FormalParameterKind.requiredPositional, MemberKind.ExtensionNonStaticMethod)
+                    parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.ExtensionNonStaticMethod)
                       parseMetadataStar(,)
                         listener: beginMetadataStar(int)
                         listener: endMetadataStar(0)
@@ -76,7 +76,7 @@
                       ensureIdentifier(int, formalParameterDeclaration)
                         listener: handleIdentifier(c, formalParameterDeclaration)
                       listener: handleFormalParameterWithoutValue())
-                      listener: endFormalParameter(null, null, null, c, null, null, FormalParameterKind.mandatory, MemberKind.ExtensionNonStaticMethod)
+                      listener: endFormalParameter(null, null, null, c, null, null, FormalParameterKind.requiredPositional, MemberKind.ExtensionNonStaticMethod)
                     listener: endFormalParameters(2, (, ), MemberKind.ExtensionNonStaticMethod)
               parseInitializersOpt())
                 listener: handleNoInitializers()
@@ -144,7 +144,7 @@
                 parseFormalParameters(c, MemberKind.ExtensionNonStaticMethod)
                   parseFormalParametersRest((, MemberKind.ExtensionNonStaticMethod)
                     listener: beginFormalParameters((, MemberKind.ExtensionNonStaticMethod)
-                    parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.ExtensionNonStaticMethod)
+                    parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.ExtensionNonStaticMethod)
                       parseMetadataStar(()
                         listener: beginMetadataStar(int)
                         listener: endMetadataStar(0)
@@ -155,7 +155,7 @@
                       ensureIdentifier(int, formalParameterDeclaration)
                         listener: handleIdentifier(d, formalParameterDeclaration)
                       listener: handleFormalParameterWithoutValue())
-                      listener: endFormalParameter(null, null, null, d, null, null, FormalParameterKind.mandatory, MemberKind.ExtensionNonStaticMethod)
+                      listener: endFormalParameter(null, null, null, d, null, null, FormalParameterKind.requiredPositional, MemberKind.ExtensionNonStaticMethod)
                     listener: endFormalParameters(1, (, ), MemberKind.ExtensionNonStaticMethod)
               parseInitializersOpt())
                 listener: handleNoInitializers()
@@ -191,7 +191,7 @@
           parseFormalParameters(f, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(List)
                   listener: endMetadataStar(0)
@@ -206,7 +206,7 @@
                 ensureIdentifier(>, formalParameterDeclaration)
                   listener: handleIdentifier(l, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, l, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, l, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -269,7 +269,7 @@
           parseFormalParameters(g, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(List)
                   listener: endMetadataStar(0)
@@ -284,7 +284,7 @@
                 ensureIdentifier(>, formalParameterDeclaration)
                   listener: handleIdentifier(l, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, l, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, l, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/error_recovery/issue_22314.dart.expect b/pkg/front_end/parser_testcases/error_recovery/issue_22314.dart.expect
index 8b091c3..7bc6b89 100644
--- a/pkg/front_end/parser_testcases/error_recovery/issue_22314.dart.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/issue_22314.dart.expect
@@ -57,7 +57,7 @@
                 handleNoType(()
                 handleIdentifier(message, fieldInitializer)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(this, null, ., message, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(this, null, ., message, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/error_recovery/issue_22314.dart.intertwined.expect b/pkg/front_end/parser_testcases/error_recovery/issue_22314.dart.intertwined.expect
index ef38c2b..557ff88 100644
--- a/pkg/front_end/parser_testcases/error_recovery/issue_22314.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/issue_22314.dart.intertwined.expect
@@ -82,7 +82,7 @@
                   parseFormalParameters(Annotation, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(this)
                           listener: endMetadataStar(0)
@@ -91,7 +91,7 @@
                         ensureIdentifier(., fieldInitializer)
                           listener: handleIdentifier(message, fieldInitializer)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(this, null, ., message, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(this, null, ., message, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
diff --git a/pkg/front_end/parser_testcases/error_recovery/issue_26073.dart.expect b/pkg/front_end/parser_testcases/error_recovery/issue_26073.dart.expect
index 942e5ce..c7790de 100644
--- a/pkg/front_end/parser_testcases/error_recovery/issue_26073.dart.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/issue_26073.dart.expect
@@ -53,7 +53,7 @@
             handleType(int, null)
             handleIdentifier(x, formalParameterDeclaration)
             handleFormalParameterWithoutValue())
-          endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+          endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
         endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
       endFunctionType(Function, null)
     endTypedef(typedef, =, ;)
@@ -76,7 +76,7 @@
             handleType(int, null)
             handleIdentifier(x, formalParameterDeclaration)
             handleFormalParameterWithoutValue())
-          endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+          endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
         endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
       endFunctionType(Function, null)
     endTypedef(typedef, =, ;)
@@ -102,7 +102,7 @@
             handleType(int, null)
             handleIdentifier(x, formalParameterDeclaration)
             handleFormalParameterWithoutValue())
-          endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+          endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
         endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
       endFunctionType(Function, null)
     endTypedef(typedef, =, ;)
@@ -126,7 +126,7 @@
             handleType(int, null)
             handleIdentifier(x, formalParameterDeclaration)
             handleFormalParameterWithoutValue())
-          endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+          endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
         endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
       endFunctionType(Function, null)
     endTypedef(typedef, =, ;)
@@ -156,7 +156,7 @@
             handleType(int, null)
             handleIdentifier(x, formalParameterDeclaration)
             handleFormalParameterWithoutValue())
-          endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+          endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
         endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
       endFunctionType(Function, null)
     endTypedef(typedef, =, ;)
@@ -188,7 +188,7 @@
             handleType(int, null)
             handleIdentifier(x, formalParameterDeclaration)
             handleFormalParameterWithoutValue())
-          endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+          endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
         endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
       endFunctionType(Function, null)
     endTypedef(typedef, =, ;)
@@ -230,7 +230,7 @@
             handleType(int, null)
             handleIdentifier(x, formalParameterDeclaration)
             handleFormalParameterWithoutValue())
-          endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+          endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
         endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
       endFunctionType(Function, null)
     endTypedef(typedef, =, ;)
@@ -286,7 +286,7 @@
             handleType(int, null)
             handleIdentifier(x, formalParameterDeclaration)
             handleFormalParameterWithoutValue())
-          endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+          endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
         endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
       endFunctionType(Function, null)
     endTypedef(typedef, =, ;)
diff --git a/pkg/front_end/parser_testcases/error_recovery/issue_26073.dart.intertwined.expect b/pkg/front_end/parser_testcases/error_recovery/issue_26073.dart.intertwined.expect
index 8eca861..2d1c17f 100644
--- a/pkg/front_end/parser_testcases/error_recovery/issue_26073.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/issue_26073.dart.intertwined.expect
@@ -22,7 +22,7 @@
         parseFormalParametersRequiredOpt(Function, MemberKind.GeneralizedFunctionType)
           parseFormalParametersRest((, MemberKind.GeneralizedFunctionType)
             listener: beginFormalParameters((, MemberKind.GeneralizedFunctionType)
-            parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+            parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
               parseMetadataStar(()
                 listener: beginMetadataStar(int)
                 listener: endMetadataStar(0)
@@ -33,7 +33,7 @@
               ensureIdentifier(int, formalParameterDeclaration)
                 listener: handleIdentifier(x, formalParameterDeclaration)
               listener: handleFormalParameterWithoutValue())
-              listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+              listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
             listener: endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
         listener: endFunctionType(Function, null)
         ensureSemicolon())
@@ -56,7 +56,7 @@
         parseFormalParametersRequiredOpt(Function, MemberKind.GeneralizedFunctionType)
           parseFormalParametersRest((, MemberKind.GeneralizedFunctionType)
             listener: beginFormalParameters((, MemberKind.GeneralizedFunctionType)
-            parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+            parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
               parseMetadataStar(()
                 listener: beginMetadataStar(int)
                 listener: endMetadataStar(0)
@@ -67,7 +67,7 @@
               ensureIdentifier(int, formalParameterDeclaration)
                 listener: handleIdentifier(x, formalParameterDeclaration)
               listener: handleFormalParameterWithoutValue())
-              listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+              listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
             listener: endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
         listener: endFunctionType(Function, null)
         ensureSemicolon())
@@ -96,7 +96,7 @@
         parseFormalParametersRequiredOpt(Function, MemberKind.GeneralizedFunctionType)
           parseFormalParametersRest((, MemberKind.GeneralizedFunctionType)
             listener: beginFormalParameters((, MemberKind.GeneralizedFunctionType)
-            parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+            parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
               parseMetadataStar(()
                 listener: beginMetadataStar(int)
                 listener: endMetadataStar(0)
@@ -107,7 +107,7 @@
               ensureIdentifier(int, formalParameterDeclaration)
                 listener: handleIdentifier(x, formalParameterDeclaration)
               listener: handleFormalParameterWithoutValue())
-              listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+              listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
             listener: endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
         listener: endFunctionType(Function, null)
         ensureSemicolon())
@@ -133,7 +133,7 @@
         parseFormalParametersRequiredOpt(Function, MemberKind.GeneralizedFunctionType)
           parseFormalParametersRest((, MemberKind.GeneralizedFunctionType)
             listener: beginFormalParameters((, MemberKind.GeneralizedFunctionType)
-            parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+            parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
               parseMetadataStar(()
                 listener: beginMetadataStar(int)
                 listener: endMetadataStar(0)
@@ -144,7 +144,7 @@
               ensureIdentifier(int, formalParameterDeclaration)
                 listener: handleIdentifier(x, formalParameterDeclaration)
               listener: handleFormalParameterWithoutValue())
-              listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+              listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
             listener: endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
         listener: endFunctionType(Function, null)
         ensureSemicolon())
@@ -177,7 +177,7 @@
         parseFormalParametersRequiredOpt(Function, MemberKind.GeneralizedFunctionType)
           parseFormalParametersRest((, MemberKind.GeneralizedFunctionType)
             listener: beginFormalParameters((, MemberKind.GeneralizedFunctionType)
-            parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+            parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
               parseMetadataStar(()
                 listener: beginMetadataStar(int)
                 listener: endMetadataStar(0)
@@ -188,7 +188,7 @@
               ensureIdentifier(int, formalParameterDeclaration)
                 listener: handleIdentifier(x, formalParameterDeclaration)
               listener: handleFormalParameterWithoutValue())
-              listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+              listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
             listener: endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
         listener: endFunctionType(Function, null)
         ensureSemicolon())
@@ -222,7 +222,7 @@
         parseFormalParametersRequiredOpt(>, MemberKind.GeneralizedFunctionType)
           parseFormalParametersRest((, MemberKind.GeneralizedFunctionType)
             listener: beginFormalParameters((, MemberKind.GeneralizedFunctionType)
-            parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+            parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
               parseMetadataStar(()
                 listener: beginMetadataStar(int)
                 listener: endMetadataStar(0)
@@ -233,7 +233,7 @@
               ensureIdentifier(int, formalParameterDeclaration)
                 listener: handleIdentifier(x, formalParameterDeclaration)
               listener: handleFormalParameterWithoutValue())
-              listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+              listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
             listener: endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
         listener: endFunctionType(Function, null)
         ensureSemicolon())
@@ -278,7 +278,7 @@
         parseFormalParametersRequiredOpt(Function, MemberKind.GeneralizedFunctionType)
           parseFormalParametersRest((, MemberKind.GeneralizedFunctionType)
             listener: beginFormalParameters((, MemberKind.GeneralizedFunctionType)
-            parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+            parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
               parseMetadataStar(()
                 listener: beginMetadataStar(int)
                 listener: endMetadataStar(0)
@@ -289,7 +289,7 @@
               ensureIdentifier(int, formalParameterDeclaration)
                 listener: handleIdentifier(x, formalParameterDeclaration)
               listener: handleFormalParameterWithoutValue())
-              listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+              listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
             listener: endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
         listener: endFunctionType(Function, null)
         ensureSemicolon())
@@ -357,7 +357,7 @@
         parseFormalParametersRequiredOpt(>, MemberKind.GeneralizedFunctionType)
           parseFormalParametersRest((, MemberKind.GeneralizedFunctionType)
             listener: beginFormalParameters((, MemberKind.GeneralizedFunctionType)
-            parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+            parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
               parseMetadataStar(()
                 listener: beginMetadataStar(int)
                 listener: endMetadataStar(0)
@@ -368,7 +368,7 @@
               ensureIdentifier(int, formalParameterDeclaration)
                 listener: handleIdentifier(x, formalParameterDeclaration)
               listener: handleFormalParameterWithoutValue())
-              listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+              listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
             listener: endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
         listener: endFunctionType(Function, null)
         ensureSemicolon())
diff --git a/pkg/front_end/parser_testcases/error_recovery/issue_26810.dart.expect b/pkg/front_end/parser_testcases/error_recovery/issue_26810.dart.expect
index d1fcfd2..e6bfd54 100644
--- a/pkg/front_end/parser_testcases/error_recovery/issue_26810.dart.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/issue_26810.dart.expect
@@ -387,7 +387,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue(,)
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
               beginMetadataStar(int)
               endMetadataStar(0)
               beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
@@ -396,7 +396,7 @@
                 handleType(int, null)
                 handleIdentifier(y, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -432,7 +432,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue(,)
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
               beginMetadataStar(int)
               endMetadataStar(0)
               beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
@@ -441,7 +441,7 @@
                 handleType(int, null)
                 handleIdentifier(y, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -476,7 +476,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue(,)
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
               beginMetadataStar(int)
               endMetadataStar(0)
               beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
@@ -485,7 +485,7 @@
                 handleType(int, null)
                 handleIdentifier(y, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -524,7 +524,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue(,)
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
               beginMetadataStar(int)
               endMetadataStar(0)
               beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
@@ -533,7 +533,7 @@
                 handleType(int, null)
                 handleIdentifier(y, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -571,7 +571,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue(,)
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
               beginMetadataStar(int)
               endMetadataStar(0)
               beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
@@ -580,7 +580,7 @@
                 handleType(int, null)
                 handleIdentifier(y, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -635,7 +635,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue(,)
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
               beginMetadataStar(int)
               endMetadataStar(0)
               beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
@@ -644,7 +644,7 @@
                 handleType(int, null)
                 handleIdentifier(y, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -698,7 +698,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue(,)
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
               beginMetadataStar(int)
               endMetadataStar(0)
               beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
@@ -707,7 +707,7 @@
                 handleType(int, null)
                 handleIdentifier(y, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -749,7 +749,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue(,)
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
               beginMetadataStar(int)
               endMetadataStar(0)
               beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
@@ -758,7 +758,7 @@
                 handleType(int, null)
                 handleIdentifier(y, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -799,7 +799,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue(,)
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
               beginMetadataStar(int)
               endMetadataStar(0)
               beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
@@ -808,7 +808,7 @@
                 handleType(int, null)
                 handleIdentifier(y, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -853,7 +853,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue(,)
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
               beginMetadataStar(int)
               endMetadataStar(0)
               beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
@@ -862,7 +862,7 @@
                 handleType(int, null)
                 handleIdentifier(y, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -904,7 +904,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue(,)
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
               beginMetadataStar(int)
               endMetadataStar(0)
               beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
@@ -913,7 +913,7 @@
                 handleType(int, null)
                 handleIdentifier(y, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -991,7 +991,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue(,)
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
               beginMetadataStar(int)
               endMetadataStar(0)
               beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
@@ -1000,7 +1000,7 @@
                 handleType(int, null)
                 handleIdentifier(y, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
             beginInitializers(:)
               beginInitializer(foo)
@@ -1082,7 +1082,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue(,)
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
               beginMetadataStar(int)
               endMetadataStar(0)
               beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
@@ -1091,7 +1091,7 @@
                 handleType(int, null)
                 handleIdentifier(y, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
             beginInitializers(:)
               beginInitializer(foo)
@@ -1170,7 +1170,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue(,)
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
               beginMetadataStar(int)
               endMetadataStar(0)
               beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
@@ -1179,7 +1179,7 @@
                 handleType(int, null)
                 handleIdentifier(y, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/error_recovery/issue_26810.dart.intertwined.expect b/pkg/front_end/parser_testcases/error_recovery/issue_26810.dart.intertwined.expect
index c90f416..e480ced 100644
--- a/pkg/front_end/parser_testcases/error_recovery/issue_26810.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/issue_26810.dart.intertwined.expect
@@ -779,7 +779,7 @@
                   parseFormalParameters(i, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -790,8 +790,8 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue(,)
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
-                      parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(,)
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -802,7 +802,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(y, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -876,7 +876,7 @@
                   parseFormalParameters(j, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -887,8 +887,8 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue(,)
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
-                      parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(,)
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -899,7 +899,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(y, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -961,7 +961,7 @@
                   parseFormalParameters(k, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -972,8 +972,8 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue(,)
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
-                      parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(,)
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -984,7 +984,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(y, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -1065,7 +1065,7 @@
                   parseFormalParameters(l, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1076,8 +1076,8 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue(,)
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
-                      parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(,)
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1088,7 +1088,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(y, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -1157,7 +1157,7 @@
                   parseFormalParameters(m, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1168,8 +1168,8 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue(,)
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
-                      parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(,)
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1180,7 +1180,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(y, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -1296,7 +1296,7 @@
                   parseFormalParameters(n, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1307,8 +1307,8 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue(,)
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
-                      parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(,)
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1319,7 +1319,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(y, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -1423,7 +1423,7 @@
                   parseFormalParameters(o, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1434,8 +1434,8 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue(,)
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
-                      parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(,)
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1446,7 +1446,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(y, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -1539,7 +1539,7 @@
                   parseFormalParameters(p, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1550,8 +1550,8 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue(,)
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
-                      parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(,)
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1562,7 +1562,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(y, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -1638,7 +1638,7 @@
                   parseFormalParameters(q, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1649,8 +1649,8 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue(,)
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
-                      parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(,)
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1661,7 +1661,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(y, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -1761,7 +1761,7 @@
                   parseFormalParameters(r, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1772,8 +1772,8 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue(,)
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
-                      parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(,)
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1784,7 +1784,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(y, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -1866,7 +1866,7 @@
                   parseFormalParameters(s, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1877,8 +1877,8 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue(,)
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
-                      parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(,)
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1889,7 +1889,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(y, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -2104,7 +2104,7 @@
                   parseFormalParameters(Key, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -2115,8 +2115,8 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue(,)
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
-                      parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(,)
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -2127,7 +2127,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(y, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   parseInitializers(:)
@@ -2349,7 +2349,7 @@
                   parseFormalParameters(Key, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -2360,8 +2360,8 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue(,)
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
-                      parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(,)
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -2372,7 +2372,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(y, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   parseInitializers(:)
@@ -2558,7 +2558,7 @@
                   parseFormalParameters(not_currently_working, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -2569,8 +2569,8 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue(,)
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
-                      parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(,)
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -2581,7 +2581,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(y, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
diff --git a/pkg/front_end/parser_testcases/error_recovery/issue_26810_and.dart.expect b/pkg/front_end/parser_testcases/error_recovery/issue_26810_and.dart.expect
index 27098f5..80e2f29 100644
--- a/pkg/front_end/parser_testcases/error_recovery/issue_26810_and.dart.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/issue_26810_and.dart.expect
@@ -387,7 +387,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue(,)
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
               beginMetadataStar(int)
               endMetadataStar(0)
               beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
@@ -396,7 +396,7 @@
                 handleType(int, null)
                 handleIdentifier(y, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -432,7 +432,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue(,)
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
               beginMetadataStar(int)
               endMetadataStar(0)
               beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
@@ -441,7 +441,7 @@
                 handleType(int, null)
                 handleIdentifier(y, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -476,7 +476,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue(,)
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
               beginMetadataStar(int)
               endMetadataStar(0)
               beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
@@ -485,7 +485,7 @@
                 handleType(int, null)
                 handleIdentifier(y, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -524,7 +524,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue(,)
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
               beginMetadataStar(int)
               endMetadataStar(0)
               beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
@@ -533,7 +533,7 @@
                 handleType(int, null)
                 handleIdentifier(y, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -571,7 +571,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue(,)
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
               beginMetadataStar(int)
               endMetadataStar(0)
               beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
@@ -580,7 +580,7 @@
                 handleType(int, null)
                 handleIdentifier(y, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -635,7 +635,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue(,)
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
               beginMetadataStar(int)
               endMetadataStar(0)
               beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
@@ -644,7 +644,7 @@
                 handleType(int, null)
                 handleIdentifier(y, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -698,7 +698,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue(,)
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
               beginMetadataStar(int)
               endMetadataStar(0)
               beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
@@ -707,7 +707,7 @@
                 handleType(int, null)
                 handleIdentifier(y, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -749,7 +749,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue(,)
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
               beginMetadataStar(int)
               endMetadataStar(0)
               beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
@@ -758,7 +758,7 @@
                 handleType(int, null)
                 handleIdentifier(y, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -799,7 +799,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue(,)
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
               beginMetadataStar(int)
               endMetadataStar(0)
               beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
@@ -808,7 +808,7 @@
                 handleType(int, null)
                 handleIdentifier(y, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -853,7 +853,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue(,)
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
               beginMetadataStar(int)
               endMetadataStar(0)
               beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
@@ -862,7 +862,7 @@
                 handleType(int, null)
                 handleIdentifier(y, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -904,7 +904,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue(,)
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
               beginMetadataStar(int)
               endMetadataStar(0)
               beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
@@ -913,7 +913,7 @@
                 handleType(int, null)
                 handleIdentifier(y, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -991,7 +991,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue(,)
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
               beginMetadataStar(int)
               endMetadataStar(0)
               beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
@@ -1000,7 +1000,7 @@
                 handleType(int, null)
                 handleIdentifier(y, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
             beginInitializers(:)
               beginInitializer(foo)
@@ -1082,7 +1082,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue(,)
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
               beginMetadataStar(int)
               endMetadataStar(0)
               beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
@@ -1091,7 +1091,7 @@
                 handleType(int, null)
                 handleIdentifier(y, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
             beginInitializers(:)
               beginInitializer(foo)
@@ -1170,7 +1170,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue(,)
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
               beginMetadataStar(int)
               endMetadataStar(0)
               beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
@@ -1179,7 +1179,7 @@
                 handleType(int, null)
                 handleIdentifier(y, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/error_recovery/issue_26810_and.dart.intertwined.expect b/pkg/front_end/parser_testcases/error_recovery/issue_26810_and.dart.intertwined.expect
index 7a715ee..93b2ee2 100644
--- a/pkg/front_end/parser_testcases/error_recovery/issue_26810_and.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/issue_26810_and.dart.intertwined.expect
@@ -781,7 +781,7 @@
                   parseFormalParameters(i, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -792,8 +792,8 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue(,)
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
-                      parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(,)
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -804,7 +804,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(y, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -878,7 +878,7 @@
                   parseFormalParameters(j, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -889,8 +889,8 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue(,)
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
-                      parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(,)
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -901,7 +901,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(y, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -963,7 +963,7 @@
                   parseFormalParameters(k, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -974,8 +974,8 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue(,)
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
-                      parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(,)
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -986,7 +986,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(y, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -1067,7 +1067,7 @@
                   parseFormalParameters(l, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1078,8 +1078,8 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue(,)
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
-                      parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(,)
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1090,7 +1090,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(y, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -1159,7 +1159,7 @@
                   parseFormalParameters(m, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1170,8 +1170,8 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue(,)
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
-                      parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(,)
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1182,7 +1182,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(y, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -1298,7 +1298,7 @@
                   parseFormalParameters(n, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1309,8 +1309,8 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue(,)
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
-                      parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(,)
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1321,7 +1321,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(y, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -1425,7 +1425,7 @@
                   parseFormalParameters(o, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1436,8 +1436,8 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue(,)
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
-                      parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(,)
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1448,7 +1448,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(y, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -1542,7 +1542,7 @@
                   parseFormalParameters(p, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1553,8 +1553,8 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue(,)
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
-                      parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(,)
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1565,7 +1565,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(y, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -1641,7 +1641,7 @@
                   parseFormalParameters(q, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1652,8 +1652,8 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue(,)
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
-                      parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(,)
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1664,7 +1664,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(y, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -1765,7 +1765,7 @@
                   parseFormalParameters(r, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1776,8 +1776,8 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue(,)
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
-                      parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(,)
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1788,7 +1788,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(y, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -1870,7 +1870,7 @@
                   parseFormalParameters(s, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1881,8 +1881,8 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue(,)
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
-                      parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(,)
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1893,7 +1893,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(y, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -2108,7 +2108,7 @@
                   parseFormalParameters(Key, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -2119,8 +2119,8 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue(,)
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
-                      parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(,)
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -2131,7 +2131,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(y, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   parseInitializers(:)
@@ -2353,7 +2353,7 @@
                   parseFormalParameters(Key, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -2364,8 +2364,8 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue(,)
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
-                      parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(,)
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -2376,7 +2376,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(y, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   parseInitializers(:)
@@ -2562,7 +2562,7 @@
                   parseFormalParameters(not_currently_working, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -2573,8 +2573,8 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue(,)
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
-                      parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(,)
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -2585,7 +2585,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(y, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
diff --git a/pkg/front_end/parser_testcases/error_recovery/issue_26810_or.dart.expect b/pkg/front_end/parser_testcases/error_recovery/issue_26810_or.dart.expect
index 529110a..bbeb795 100644
--- a/pkg/front_end/parser_testcases/error_recovery/issue_26810_or.dart.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/issue_26810_or.dart.expect
@@ -387,7 +387,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue(,)
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
               beginMetadataStar(int)
               endMetadataStar(0)
               beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
@@ -396,7 +396,7 @@
                 handleType(int, null)
                 handleIdentifier(y, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -432,7 +432,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue(,)
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
               beginMetadataStar(int)
               endMetadataStar(0)
               beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
@@ -441,7 +441,7 @@
                 handleType(int, null)
                 handleIdentifier(y, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -476,7 +476,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue(,)
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
               beginMetadataStar(int)
               endMetadataStar(0)
               beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
@@ -485,7 +485,7 @@
                 handleType(int, null)
                 handleIdentifier(y, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -524,7 +524,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue(,)
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
               beginMetadataStar(int)
               endMetadataStar(0)
               beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
@@ -533,7 +533,7 @@
                 handleType(int, null)
                 handleIdentifier(y, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -571,7 +571,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue(,)
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
               beginMetadataStar(int)
               endMetadataStar(0)
               beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
@@ -580,7 +580,7 @@
                 handleType(int, null)
                 handleIdentifier(y, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -635,7 +635,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue(,)
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
               beginMetadataStar(int)
               endMetadataStar(0)
               beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
@@ -644,7 +644,7 @@
                 handleType(int, null)
                 handleIdentifier(y, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -698,7 +698,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue(,)
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
               beginMetadataStar(int)
               endMetadataStar(0)
               beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
@@ -707,7 +707,7 @@
                 handleType(int, null)
                 handleIdentifier(y, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -749,7 +749,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue(,)
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
               beginMetadataStar(int)
               endMetadataStar(0)
               beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
@@ -758,7 +758,7 @@
                 handleType(int, null)
                 handleIdentifier(y, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -799,7 +799,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue(,)
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
               beginMetadataStar(int)
               endMetadataStar(0)
               beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
@@ -808,7 +808,7 @@
                 handleType(int, null)
                 handleIdentifier(y, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -853,7 +853,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue(,)
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
               beginMetadataStar(int)
               endMetadataStar(0)
               beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
@@ -862,7 +862,7 @@
                 handleType(int, null)
                 handleIdentifier(y, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -904,7 +904,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue(,)
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
               beginMetadataStar(int)
               endMetadataStar(0)
               beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
@@ -913,7 +913,7 @@
                 handleType(int, null)
                 handleIdentifier(y, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -991,7 +991,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue(,)
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
               beginMetadataStar(int)
               endMetadataStar(0)
               beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
@@ -1000,7 +1000,7 @@
                 handleType(int, null)
                 handleIdentifier(y, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
             beginInitializers(:)
               beginInitializer(foo)
@@ -1082,7 +1082,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue(,)
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
               beginMetadataStar(int)
               endMetadataStar(0)
               beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
@@ -1091,7 +1091,7 @@
                 handleType(int, null)
                 handleIdentifier(y, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
             beginInitializers(:)
               beginInitializer(foo)
@@ -1170,7 +1170,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue(,)
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
               beginMetadataStar(int)
               endMetadataStar(0)
               beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
@@ -1179,7 +1179,7 @@
                 handleType(int, null)
                 handleIdentifier(y, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/error_recovery/issue_26810_or.dart.intertwined.expect b/pkg/front_end/parser_testcases/error_recovery/issue_26810_or.dart.intertwined.expect
index 8c0dec2..897cffb 100644
--- a/pkg/front_end/parser_testcases/error_recovery/issue_26810_or.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/issue_26810_or.dart.intertwined.expect
@@ -781,7 +781,7 @@
                   parseFormalParameters(i, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -792,8 +792,8 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue(,)
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
-                      parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(,)
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -804,7 +804,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(y, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -878,7 +878,7 @@
                   parseFormalParameters(j, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -889,8 +889,8 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue(,)
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
-                      parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(,)
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -901,7 +901,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(y, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -963,7 +963,7 @@
                   parseFormalParameters(k, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -974,8 +974,8 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue(,)
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
-                      parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(,)
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -986,7 +986,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(y, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -1067,7 +1067,7 @@
                   parseFormalParameters(l, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1078,8 +1078,8 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue(,)
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
-                      parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(,)
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1090,7 +1090,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(y, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -1159,7 +1159,7 @@
                   parseFormalParameters(m, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1170,8 +1170,8 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue(,)
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
-                      parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(,)
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1182,7 +1182,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(y, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -1298,7 +1298,7 @@
                   parseFormalParameters(n, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1309,8 +1309,8 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue(,)
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
-                      parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(,)
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1321,7 +1321,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(y, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -1425,7 +1425,7 @@
                   parseFormalParameters(o, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1436,8 +1436,8 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue(,)
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
-                      parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(,)
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1448,7 +1448,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(y, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -1542,7 +1542,7 @@
                   parseFormalParameters(p, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1553,8 +1553,8 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue(,)
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
-                      parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(,)
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1565,7 +1565,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(y, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -1641,7 +1641,7 @@
                   parseFormalParameters(q, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1652,8 +1652,8 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue(,)
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
-                      parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(,)
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1664,7 +1664,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(y, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -1765,7 +1765,7 @@
                   parseFormalParameters(r, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1776,8 +1776,8 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue(,)
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
-                      parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(,)
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1788,7 +1788,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(y, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -1870,7 +1870,7 @@
                   parseFormalParameters(s, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1881,8 +1881,8 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue(,)
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
-                      parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(,)
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1893,7 +1893,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(y, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -2108,7 +2108,7 @@
                   parseFormalParameters(Key, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -2119,8 +2119,8 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue(,)
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
-                      parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(,)
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -2131,7 +2131,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(y, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   parseInitializers(:)
@@ -2353,7 +2353,7 @@
                   parseFormalParameters(Key, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -2364,8 +2364,8 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue(,)
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
-                      parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(,)
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -2376,7 +2376,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(y, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   parseInitializers(:)
@@ -2562,7 +2562,7 @@
                   parseFormalParameters(not_currently_working, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -2573,8 +2573,8 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue(,)
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
-                      parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(,)
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -2585,7 +2585,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(y, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
diff --git a/pkg/front_end/parser_testcases/error_recovery/issue_42267.dart.expect b/pkg/front_end/parser_testcases/error_recovery/issue_42267.dart.expect
index 7d7451a..69188e8 100644
--- a/pkg/front_end/parser_testcases/error_recovery/issue_42267.dart.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/issue_42267.dart.expect
@@ -57,7 +57,7 @@
                 handleNoType(()
                 handleIdentifier(builder, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, builder, null, null, FormalParameterKind.mandatory, MemberKind.Local)
+              endFormalParameter(null, null, null, builder, null, null, FormalParameterKind.requiredPositional, MemberKind.Local)
             endFormalParameters(1, (, ), MemberKind.Local)
             handleAsyncModifier(null, null)
             handleIdentifier(builder, expression)
@@ -111,7 +111,7 @@
                 handleNoType(()
                 handleIdentifier(builder, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, builder, null, null, FormalParameterKind.mandatory, MemberKind.Local)
+              endFormalParameter(null, null, null, builder, null, null, FormalParameterKind.requiredPositional, MemberKind.Local)
             endFormalParameters(1, (, ), MemberKind.Local)
             handleAsyncModifier(null, null)
             handleIdentifier(builder, expression)
@@ -166,7 +166,7 @@
                 handleNoType(()
                 handleIdentifier(builder, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, builder, null, null, FormalParameterKind.mandatory, MemberKind.Local)
+              endFormalParameter(null, null, null, builder, null, null, FormalParameterKind.requiredPositional, MemberKind.Local)
             endFormalParameters(1, (, ), MemberKind.Local)
             handleAsyncModifier(null, null)
             handleIdentifier(builder, expression)
diff --git a/pkg/front_end/parser_testcases/error_recovery/issue_42267.dart.intertwined.expect b/pkg/front_end/parser_testcases/error_recovery/issue_42267.dart.intertwined.expect
index e3deae7..0018e7b 100644
--- a/pkg/front_end/parser_testcases/error_recovery/issue_42267.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/issue_42267.dart.intertwined.expect
@@ -106,7 +106,7 @@
                                                 parseFormalParametersRequiredOpt((, MemberKind.Local)
                                                   parseFormalParametersRest((, MemberKind.Local)
                                                     listener: beginFormalParameters((, MemberKind.Local)
-                                                    parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.Local)
+                                                    parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.Local)
                                                       parseMetadataStar(()
                                                         listener: beginMetadataStar(builder)
                                                         listener: endMetadataStar(0)
@@ -115,7 +115,7 @@
                                                       ensureIdentifier((, formalParameterDeclaration)
                                                         listener: handleIdentifier(builder, formalParameterDeclaration)
                                                       listener: handleFormalParameterWithoutValue())
-                                                      listener: endFormalParameter(null, null, null, builder, null, null, FormalParameterKind.mandatory, MemberKind.Local)
+                                                      listener: endFormalParameter(null, null, null, builder, null, null, FormalParameterKind.requiredPositional, MemberKind.Local)
                                                     listener: endFormalParameters(1, (, ), MemberKind.Local)
                                                 parseAsyncOptBody(), true, false)
                                                   parseAsyncModifierOpt())
@@ -257,7 +257,7 @@
                                                 parseFormalParametersRequiredOpt((, MemberKind.Local)
                                                   parseFormalParametersRest((, MemberKind.Local)
                                                     listener: beginFormalParameters((, MemberKind.Local)
-                                                    parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.Local)
+                                                    parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.Local)
                                                       parseMetadataStar(()
                                                         listener: beginMetadataStar(builder)
                                                         listener: endMetadataStar(0)
@@ -266,7 +266,7 @@
                                                       ensureIdentifier((, formalParameterDeclaration)
                                                         listener: handleIdentifier(builder, formalParameterDeclaration)
                                                       listener: handleFormalParameterWithoutValue())
-                                                      listener: endFormalParameter(null, null, null, builder, null, null, FormalParameterKind.mandatory, MemberKind.Local)
+                                                      listener: endFormalParameter(null, null, null, builder, null, null, FormalParameterKind.requiredPositional, MemberKind.Local)
                                                     listener: endFormalParameters(1, (, ), MemberKind.Local)
                                                 parseAsyncOptBody(), true, false)
                                                   parseAsyncModifierOpt())
@@ -410,7 +410,7 @@
                                                 parseFormalParametersRequiredOpt((, MemberKind.Local)
                                                   parseFormalParametersRest((, MemberKind.Local)
                                                     listener: beginFormalParameters((, MemberKind.Local)
-                                                    parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.Local)
+                                                    parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.Local)
                                                       parseMetadataStar(()
                                                         listener: beginMetadataStar(builder)
                                                         listener: endMetadataStar(0)
@@ -419,7 +419,7 @@
                                                       ensureIdentifier((, formalParameterDeclaration)
                                                         listener: handleIdentifier(builder, formalParameterDeclaration)
                                                       listener: handleFormalParameterWithoutValue())
-                                                      listener: endFormalParameter(null, null, null, builder, null, null, FormalParameterKind.mandatory, MemberKind.Local)
+                                                      listener: endFormalParameter(null, null, null, builder, null, null, FormalParameterKind.requiredPositional, MemberKind.Local)
                                                     listener: endFormalParameters(1, (, ), MemberKind.Local)
                                                 parseAsyncOptBody(), true, false)
                                                   parseAsyncModifierOpt())
diff --git a/pkg/front_end/parser_testcases/error_recovery/issue_44785.crash_dart.expect b/pkg/front_end/parser_testcases/error_recovery/issue_44785.crash_dart.expect
index 1e45c25..9bf88cd 100644
--- a/pkg/front_end/parser_testcases/error_recovery/issue_44785.crash_dart.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/issue_44785.crash_dart.expect
@@ -33,7 +33,7 @@
           handleType(int, null)
           handleIdentifier(a, formalParameterDeclaration)
           handleFormalParameterWithoutValue(,)
-        endFormalParameter(null, null, null, a, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, a, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
         beginMetadataStar(int)
         endMetadataStar(0)
         beginFormalParameter(int, MemberKind.TopLevelMethod, null, null, null)
@@ -42,7 +42,7 @@
           handleType(int, null)
           handleIdentifier(b, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, b, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, b, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(2, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -93,7 +93,7 @@
           handleType(int, null)
           handleIdentifier(a, formalParameterDeclaration)
           handleFormalParameterWithoutValue(,)
-        endFormalParameter(null, null, null, a, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, a, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
         beginMetadataStar(int)
         endMetadataStar(0)
         beginFormalParameter(int, MemberKind.TopLevelMethod, null, null, null)
@@ -102,7 +102,7 @@
           handleType(int, null)
           handleIdentifier(b, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, b, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, b, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(2, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/error_recovery/issue_44785.crash_dart.intertwined.expect b/pkg/front_end/parser_testcases/error_recovery/issue_44785.crash_dart.intertwined.expect
index 152a677..c213cf0 100644
--- a/pkg/front_end/parser_testcases/error_recovery/issue_44785.crash_dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/issue_44785.crash_dart.intertwined.expect
@@ -20,7 +20,7 @@
           parseFormalParameters(foo, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -31,8 +31,8 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(a, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue(,)
-                listener: endFormalParameter(null, null, null, a, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
-              parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, a, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
+              parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(,)
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -43,7 +43,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(b, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, b, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, b, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(2, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -175,7 +175,7 @@
           parseFormalParameters(bar, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -186,8 +186,8 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(a, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue(,)
-                listener: endFormalParameter(null, null, null, a, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
-              parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, a, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
+              parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(,)
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -198,7 +198,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(b, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, b, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, b, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(2, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/error_recovery/issue_44785_prime_1.crash_dart.expect b/pkg/front_end/parser_testcases/error_recovery/issue_44785_prime_1.crash_dart.expect
index 999435a..bdc7f1e 100644
--- a/pkg/front_end/parser_testcases/error_recovery/issue_44785_prime_1.crash_dart.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/issue_44785_prime_1.crash_dart.expect
@@ -41,7 +41,7 @@
           handleType(int, null)
           handleIdentifier(a, formalParameterDeclaration)
           handleFormalParameterWithoutValue(,)
-        endFormalParameter(null, null, null, a, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, a, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
         beginMetadataStar(int)
         endMetadataStar(0)
         beginFormalParameter(int, MemberKind.TopLevelMethod, null, null, null)
@@ -50,7 +50,7 @@
           handleType(int, null)
           handleIdentifier(b, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, b, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, b, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(2, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -100,7 +100,7 @@
           handleType(int, null)
           handleIdentifier(a, formalParameterDeclaration)
           handleFormalParameterWithoutValue(,)
-        endFormalParameter(null, null, null, a, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, a, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
         beginMetadataStar(int)
         endMetadataStar(0)
         beginFormalParameter(int, MemberKind.TopLevelMethod, null, null, null)
@@ -109,7 +109,7 @@
           handleType(int, null)
           handleIdentifier(b, formalParameterDeclaration)
           handleFormalParameterWithoutValue(,)
-        endFormalParameter(null, null, null, b, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, b, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
         beginMetadataStar(int)
         endMetadataStar(0)
         beginFormalParameter(int, MemberKind.TopLevelMethod, null, null, null)
@@ -118,7 +118,7 @@
           handleType(int, null)
           handleIdentifier(c, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, c, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, c, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(3, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -178,7 +178,7 @@
           handleType(int, null)
           handleIdentifier(a, formalParameterDeclaration)
           handleFormalParameterWithoutValue(,)
-        endFormalParameter(null, null, null, a, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, a, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
         beginMetadataStar(int)
         endMetadataStar(0)
         beginFormalParameter(int, MemberKind.TopLevelMethod, null, null, null)
@@ -187,7 +187,7 @@
           handleType(int, null)
           handleIdentifier(b, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, b, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, b, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(2, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -237,7 +237,7 @@
           handleType(int, null)
           handleIdentifier(a, formalParameterDeclaration)
           handleFormalParameterWithoutValue(,)
-        endFormalParameter(null, null, null, a, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, a, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
         beginMetadataStar(int)
         endMetadataStar(0)
         beginFormalParameter(int, MemberKind.TopLevelMethod, null, null, null)
@@ -246,7 +246,7 @@
           handleType(int, null)
           handleIdentifier(b, formalParameterDeclaration)
           handleFormalParameterWithoutValue(,)
-        endFormalParameter(null, null, null, b, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, b, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
         beginMetadataStar(int)
         endMetadataStar(0)
         beginFormalParameter(int, MemberKind.TopLevelMethod, null, null, null)
@@ -255,7 +255,7 @@
           handleType(int, null)
           handleIdentifier(c, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, c, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, c, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(3, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/error_recovery/issue_44785_prime_1.crash_dart.intertwined.expect b/pkg/front_end/parser_testcases/error_recovery/issue_44785_prime_1.crash_dart.intertwined.expect
index 7f659af..748a56f 100644
--- a/pkg/front_end/parser_testcases/error_recovery/issue_44785_prime_1.crash_dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/issue_44785_prime_1.crash_dart.intertwined.expect
@@ -20,7 +20,7 @@
           parseFormalParameters(foo, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -31,8 +31,8 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(a, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue(,)
-                listener: endFormalParameter(null, null, null, a, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
-              parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, a, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
+              parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(,)
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -43,7 +43,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(b, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, b, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, b, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(2, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -172,7 +172,7 @@
           parseFormalParameters(foo2, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -183,8 +183,8 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(a, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue(,)
-                listener: endFormalParameter(null, null, null, a, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
-              parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, a, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
+              parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(,)
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -195,8 +195,8 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(b, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue(,)
-                listener: endFormalParameter(null, null, null, b, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
-              parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, b, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
+              parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(,)
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -207,7 +207,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(c, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, c, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, c, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(3, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -384,7 +384,7 @@
           parseFormalParameters(bar, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -395,8 +395,8 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(a, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue(,)
-                listener: endFormalParameter(null, null, null, a, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
-              parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, a, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
+              parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(,)
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -407,7 +407,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(b, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, b, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, b, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(2, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -536,7 +536,7 @@
           parseFormalParameters(bar2, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -547,8 +547,8 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(a, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue(,)
-                listener: endFormalParameter(null, null, null, a, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
-              parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, a, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
+              parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(,)
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -559,8 +559,8 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(b, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue(,)
-                listener: endFormalParameter(null, null, null, b, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
-              parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, b, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
+              parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(,)
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -571,7 +571,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(c, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, c, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, c, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(3, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/error_recovery/issue_44785_prime_2.crash_dart.expect b/pkg/front_end/parser_testcases/error_recovery/issue_44785_prime_2.crash_dart.expect
index 4d1bbe5..488b2e2 100644
--- a/pkg/front_end/parser_testcases/error_recovery/issue_44785_prime_2.crash_dart.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/issue_44785_prime_2.crash_dart.expect
@@ -15,7 +15,7 @@
           handleType(int, null)
           handleIdentifier(a, formalParameterDeclaration)
           handleFormalParameterWithoutValue(,)
-        endFormalParameter(null, null, null, a, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, a, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
         beginMetadataStar(int)
         endMetadataStar(0)
         beginFormalParameter(int, MemberKind.TopLevelMethod, null, null, null)
@@ -24,7 +24,7 @@
           handleType(int, null)
           handleIdentifier(b, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, b, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, b, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(2, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -73,7 +73,7 @@
           handleType(int, null)
           handleIdentifier(a, formalParameterDeclaration)
           handleFormalParameterWithoutValue(,)
-        endFormalParameter(null, null, null, a, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, a, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
         beginMetadataStar(int)
         endMetadataStar(0)
         beginFormalParameter(int, MemberKind.TopLevelMethod, null, null, null)
@@ -82,7 +82,7 @@
           handleType(int, null)
           handleIdentifier(b, formalParameterDeclaration)
           handleFormalParameterWithoutValue(,)
-        endFormalParameter(null, null, null, b, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, b, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
         beginMetadataStar(int)
         endMetadataStar(0)
         beginFormalParameter(int, MemberKind.TopLevelMethod, null, null, null)
@@ -91,7 +91,7 @@
           handleType(int, null)
           handleIdentifier(c, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, c, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, c, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(3, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -149,7 +149,7 @@
           handleType(int, null)
           handleIdentifier(a, formalParameterDeclaration)
           handleFormalParameterWithoutValue(,)
-        endFormalParameter(null, null, null, a, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, a, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
         beginMetadataStar(int)
         endMetadataStar(0)
         beginFormalParameter(int, MemberKind.TopLevelMethod, null, null, null)
@@ -158,7 +158,7 @@
           handleType(int, null)
           handleIdentifier(b, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, b, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, b, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(2, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -207,7 +207,7 @@
           handleType(int, null)
           handleIdentifier(a, formalParameterDeclaration)
           handleFormalParameterWithoutValue(,)
-        endFormalParameter(null, null, null, a, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, a, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
         beginMetadataStar(int)
         endMetadataStar(0)
         beginFormalParameter(int, MemberKind.TopLevelMethod, null, null, null)
@@ -216,7 +216,7 @@
           handleType(int, null)
           handleIdentifier(b, formalParameterDeclaration)
           handleFormalParameterWithoutValue(,)
-        endFormalParameter(null, null, null, b, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, b, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
         beginMetadataStar(int)
         endMetadataStar(0)
         beginFormalParameter(int, MemberKind.TopLevelMethod, null, null, null)
@@ -225,7 +225,7 @@
           handleType(int, null)
           handleIdentifier(c, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, c, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, c, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(3, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/error_recovery/issue_44785_prime_2.crash_dart.intertwined.expect b/pkg/front_end/parser_testcases/error_recovery/issue_44785_prime_2.crash_dart.intertwined.expect
index 7e08a7b..afefe42 100644
--- a/pkg/front_end/parser_testcases/error_recovery/issue_44785_prime_2.crash_dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/issue_44785_prime_2.crash_dart.intertwined.expect
@@ -20,7 +20,7 @@
           parseFormalParameters(foo, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -31,8 +31,8 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(a, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue(,)
-                listener: endFormalParameter(null, null, null, a, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
-              parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, a, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
+              parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(,)
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -43,7 +43,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(b, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, b, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, b, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(2, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -146,7 +146,7 @@
           parseFormalParameters(foo2, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -157,8 +157,8 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(a, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue(,)
-                listener: endFormalParameter(null, null, null, a, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
-              parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, a, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
+              parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(,)
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -169,8 +169,8 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(b, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue(,)
-                listener: endFormalParameter(null, null, null, b, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
-              parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, b, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
+              parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(,)
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -181,7 +181,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(c, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, c, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, c, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(3, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -305,7 +305,7 @@
           parseFormalParameters(bar, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -316,8 +316,8 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(a, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue(,)
-                listener: endFormalParameter(null, null, null, a, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
-              parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, a, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
+              parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(,)
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -328,7 +328,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(b, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, b, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, b, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(2, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -431,7 +431,7 @@
           parseFormalParameters(bar2, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -442,8 +442,8 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(a, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue(,)
-                listener: endFormalParameter(null, null, null, a, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
-              parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, a, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
+              parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(,)
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -454,8 +454,8 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(b, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue(,)
-                listener: endFormalParameter(null, null, null, b, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
-              parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, b, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
+              parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(,)
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -466,7 +466,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(c, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, c, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, c, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(3, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/error_recovery/issue_45327_prime_1.crash_dart.expect b/pkg/front_end/parser_testcases/error_recovery/issue_45327_prime_1.crash_dart.expect
index d543918..4344e3d 100644
--- a/pkg/front_end/parser_testcases/error_recovery/issue_45327_prime_1.crash_dart.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/issue_45327_prime_1.crash_dart.expect
@@ -45,7 +45,7 @@
                 handleType(Object, ?)
                 handleIdentifier(key, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, key, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, key, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/error_recovery/issue_45327_prime_1.crash_dart.intertwined.expect b/pkg/front_end/parser_testcases/error_recovery/issue_45327_prime_1.crash_dart.intertwined.expect
index 4efe113..4684887 100644
--- a/pkg/front_end/parser_testcases/error_recovery/issue_45327_prime_1.crash_dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/issue_45327_prime_1.crash_dart.intertwined.expect
@@ -52,7 +52,7 @@
                   parseFormalParameters(foo, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(Object)
                           listener: endMetadataStar(0)
@@ -63,7 +63,7 @@
                         ensureIdentifier(?, formalParameterDeclaration)
                           listener: handleIdentifier(key, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, key, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, key, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
diff --git a/pkg/front_end/parser_testcases/error_recovery/issue_46505_prime_6.crash_dart.expect b/pkg/front_end/parser_testcases/error_recovery/issue_46505_prime_6.crash_dart.expect
index 499a3c6..5e11902 100644
--- a/pkg/front_end/parser_testcases/error_recovery/issue_46505_prime_6.crash_dart.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/issue_46505_prime_6.crash_dart.expect
@@ -47,7 +47,7 @@
                 handleType(T, null)
                 handleIdentifier(foo, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, foo, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, foo, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -86,7 +86,7 @@
                 handleType(T, null)
                 handleIdentifier(foo, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, foo, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, foo, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -118,7 +118,7 @@
                 handleType(T, null)
                 handleIdentifier(foo, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, foo, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, foo, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/error_recovery/issue_46505_prime_6.crash_dart.intertwined.expect b/pkg/front_end/parser_testcases/error_recovery/issue_46505_prime_6.crash_dart.intertwined.expect
index 81224ad..28d1be1 100644
--- a/pkg/front_end/parser_testcases/error_recovery/issue_46505_prime_6.crash_dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/issue_46505_prime_6.crash_dart.intertwined.expect
@@ -60,7 +60,7 @@
                   parseFormalParameters(>, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(T)
                           listener: endMetadataStar(0)
@@ -71,7 +71,7 @@
                         ensureIdentifier(T, formalParameterDeclaration)
                           listener: handleIdentifier(foo, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, foo, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, foo, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -124,7 +124,7 @@
                   parseFormalParameters(>, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(T)
                           listener: endMetadataStar(0)
@@ -135,7 +135,7 @@
                         ensureIdentifier(T, formalParameterDeclaration)
                           listener: handleIdentifier(foo, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, foo, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, foo, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -176,7 +176,7 @@
                   parseFormalParameters(>, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(T)
                           listener: endMetadataStar(0)
@@ -187,7 +187,7 @@
                         ensureIdentifier(T, formalParameterDeclaration)
                           listener: handleIdentifier(foo, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, foo, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, foo, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
diff --git a/pkg/front_end/parser_testcases/error_recovery/issue_46736.dart.expect b/pkg/front_end/parser_testcases/error_recovery/issue_46736.dart.expect
index 1404e10..b455d26 100644
--- a/pkg/front_end/parser_testcases/error_recovery/issue_46736.dart.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/issue_46736.dart.expect
@@ -22,7 +22,7 @@
           handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'default' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: default}], default, default)
           handleIdentifier(default, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, default, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, default, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/error_recovery/issue_46736.dart.intertwined.expect b/pkg/front_end/parser_testcases/error_recovery/issue_46736.dart.intertwined.expect
index 8b1d296..122fa9b 100644
--- a/pkg/front_end/parser_testcases/error_recovery/issue_46736.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/issue_46736.dart.intertwined.expect
@@ -19,7 +19,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(String)
                   listener: endMetadataStar(0)
@@ -32,7 +32,7 @@
                     listener: handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'default' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: default}], default, default)
                   listener: handleIdentifier(default, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, default, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, default, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/error_recovery/issue_46736_prime.dart.expect b/pkg/front_end/parser_testcases/error_recovery/issue_46736_prime.dart.expect
index 74df9c4..63cba8a 100644
--- a/pkg/front_end/parser_testcases/error_recovery/issue_46736_prime.dart.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/issue_46736_prime.dart.expect
@@ -15,7 +15,7 @@
           handleType(String, null)
           handleIdentifier(defaultX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, defaultX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, defaultX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/error_recovery/issue_46736_prime.dart.intertwined.expect b/pkg/front_end/parser_testcases/error_recovery/issue_46736_prime.dart.intertwined.expect
index f165cd4..261da80 100644
--- a/pkg/front_end/parser_testcases/error_recovery/issue_46736_prime.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/issue_46736_prime.dart.intertwined.expect
@@ -19,7 +19,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(String)
                   listener: endMetadataStar(0)
@@ -30,7 +30,7 @@
                 ensureIdentifier(String, formalParameterDeclaration)
                   listener: handleIdentifier(defaultX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, defaultX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, defaultX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/error_recovery/issue_48288.dart.expect b/pkg/front_end/parser_testcases/error_recovery/issue_48288.dart.expect
index a19ccf7..660963d 100644
--- a/pkg/front_end/parser_testcases/error_recovery/issue_48288.dart.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/issue_48288.dart.expect
@@ -21,7 +21,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/error_recovery/issue_48288.dart.intertwined.expect b/pkg/front_end/parser_testcases/error_recovery/issue_48288.dart.intertwined.expect
index 1c7b843..3c69aee 100644
--- a/pkg/front_end/parser_testcases/error_recovery/issue_48288.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/issue_48288.dart.intertwined.expect
@@ -19,7 +19,7 @@
           parseFormalParameters(f, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -30,7 +30,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/error_recovery/issue_48288_prime.dart.expect b/pkg/front_end/parser_testcases/error_recovery/issue_48288_prime.dart.expect
index 061f44a..2211671 100644
--- a/pkg/front_end/parser_testcases/error_recovery/issue_48288_prime.dart.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/issue_48288_prime.dart.expect
@@ -15,7 +15,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/error_recovery/issue_48288_prime.dart.intertwined.expect b/pkg/front_end/parser_testcases/error_recovery/issue_48288_prime.dart.intertwined.expect
index def81ae..e7e4c1e 100644
--- a/pkg/front_end/parser_testcases/error_recovery/issue_48288_prime.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/issue_48288_prime.dart.intertwined.expect
@@ -19,7 +19,7 @@
           parseFormalParameters(f, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -30,7 +30,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/error_recovery/issue_48371_prime3.dart.expect b/pkg/front_end/parser_testcases/error_recovery/issue_48371_prime3.dart.expect
index e02aece..8ca4377 100644
--- a/pkg/front_end/parser_testcases/error_recovery/issue_48371_prime3.dart.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/issue_48371_prime3.dart.expect
@@ -55,7 +55,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/error_recovery/issue_48371_prime3.dart.intertwined.expect b/pkg/front_end/parser_testcases/error_recovery/issue_48371_prime3.dart.intertwined.expect
index 81e1bf1..9e7e4e6 100644
--- a/pkg/front_end/parser_testcases/error_recovery/issue_48371_prime3.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/issue_48371_prime3.dart.intertwined.expect
@@ -79,7 +79,7 @@
                   parseFormalParameters(foo, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -90,7 +90,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
diff --git a/pkg/front_end/parser_testcases/error_recovery/issue_48411.dart.expect b/pkg/front_end/parser_testcases/error_recovery/issue_48411.dart.expect
index 9cff1ec..8f0651c 100644
--- a/pkg/front_end/parser_testcases/error_recovery/issue_48411.dart.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/issue_48411.dart.expect
@@ -53,7 +53,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -78,7 +78,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -118,7 +118,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             beginInitializers(:)
               beginInitializer(assert)
@@ -182,7 +182,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             beginInitializers(:)
               beginInitializer(assert)
@@ -248,7 +248,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             beginInitializers(:)
               beginInitializer(assert)
@@ -299,7 +299,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -350,7 +350,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             beginInitializers(:)
               beginInitializer(assert)
@@ -414,7 +414,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             beginInitializers(:)
               beginInitializer(assert)
@@ -492,7 +492,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             beginInitializers(:)
               beginInitializer(assert)
diff --git a/pkg/front_end/parser_testcases/error_recovery/issue_48411.dart.intertwined.expect b/pkg/front_end/parser_testcases/error_recovery/issue_48411.dart.intertwined.expect
index 891b53a..2cad8a9 100644
--- a/pkg/front_end/parser_testcases/error_recovery/issue_48411.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/issue_48411.dart.intertwined.expect
@@ -44,7 +44,7 @@
                   parseFormalParameters(A, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -55,7 +55,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -90,7 +90,7 @@
                   parseFormalParameters(y, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -101,7 +101,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -162,7 +162,7 @@
                   parseFormalParameters(B, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -173,7 +173,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   parseInitializers(:)
@@ -295,7 +295,7 @@
                   parseFormalParameters(B2, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -306,7 +306,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   parseInitializers(:)
@@ -436,7 +436,7 @@
                   parseFormalParameters(B3, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -447,7 +447,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   parseInitializers(:)
@@ -550,7 +550,7 @@
                   parseFormalParameters(y, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -561,7 +561,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -639,7 +639,7 @@
                   parseFormalParameters(C, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -650,7 +650,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   parseInitializers(:)
@@ -772,7 +772,7 @@
                   parseFormalParameters(D, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -783,7 +783,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   parseInitializers(:)
@@ -925,7 +925,7 @@
                   parseFormalParameters(E, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -936,7 +936,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   parseInitializers(:)
diff --git a/pkg/front_end/parser_testcases/error_recovery/issue_48411_prime.dart.expect b/pkg/front_end/parser_testcases/error_recovery/issue_48411_prime.dart.expect
index 6b97b24..247be6f 100644
--- a/pkg/front_end/parser_testcases/error_recovery/issue_48411_prime.dart.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/issue_48411_prime.dart.expect
@@ -27,7 +27,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -52,7 +52,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -92,7 +92,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             beginInitializers(:)
               beginInitializer(assert)
@@ -155,7 +155,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             beginInitializers(:)
               beginInitializer(assert)
@@ -220,7 +220,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             beginInitializers(:)
               beginInitializer(assert)
@@ -270,7 +270,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -321,7 +321,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             beginInitializers(:)
               beginInitializer(assert)
@@ -384,7 +384,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             beginInitializers(:)
               beginInitializer(assert)
@@ -461,7 +461,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             beginInitializers(:)
               beginInitializer(assert)
diff --git a/pkg/front_end/parser_testcases/error_recovery/issue_48411_prime.dart.intertwined.expect b/pkg/front_end/parser_testcases/error_recovery/issue_48411_prime.dart.intertwined.expect
index 40c0fe6..baded31 100644
--- a/pkg/front_end/parser_testcases/error_recovery/issue_48411_prime.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/issue_48411_prime.dart.intertwined.expect
@@ -44,7 +44,7 @@
                   parseFormalParameters(A, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -55,7 +55,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -90,7 +90,7 @@
                   parseFormalParameters(y, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -101,7 +101,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -162,7 +162,7 @@
                   parseFormalParameters(B, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -173,7 +173,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   parseInitializers(:)
@@ -292,7 +292,7 @@
                   parseFormalParameters(B2, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -303,7 +303,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   parseInitializers(:)
@@ -430,7 +430,7 @@
                   parseFormalParameters(B3, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -441,7 +441,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   parseInitializers(:)
@@ -541,7 +541,7 @@
                   parseFormalParameters(y, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -552,7 +552,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -630,7 +630,7 @@
                   parseFormalParameters(C, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -641,7 +641,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   parseInitializers(:)
@@ -760,7 +760,7 @@
                   parseFormalParameters(D, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -771,7 +771,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   parseInitializers(:)
@@ -910,7 +910,7 @@
                   parseFormalParameters(E, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -921,7 +921,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   parseInitializers(:)
diff --git a/pkg/front_end/parser_testcases/error_recovery/keyword_named_class_methods.dart.expect b/pkg/front_end/parser_testcases/error_recovery/keyword_named_class_methods.dart.expect
index 6eb5e42..902c6a8 100644
--- a/pkg/front_end/parser_testcases/error_recovery/keyword_named_class_methods.dart.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/keyword_named_class_methods.dart.expect
@@ -511,7 +511,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -569,7 +569,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -628,7 +628,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -684,7 +684,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -742,7 +742,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -801,7 +801,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -866,7 +866,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -926,7 +926,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -986,7 +986,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -1046,7 +1046,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -1110,7 +1110,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -1174,7 +1174,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -1233,7 +1233,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -1292,7 +1292,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -1351,7 +1351,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -1425,7 +1425,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -1484,7 +1484,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -1554,7 +1554,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -1613,7 +1613,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -1672,7 +1672,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -1731,7 +1731,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -1789,7 +1789,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -1847,7 +1847,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -1906,7 +1906,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -1965,7 +1965,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -2052,7 +2052,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -2112,7 +2112,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -2191,7 +2191,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -2249,7 +2249,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -2307,7 +2307,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -2366,7 +2366,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -2436,7 +2436,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -2494,7 +2494,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -2553,7 +2553,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -2612,7 +2612,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -2670,7 +2670,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -2729,7 +2729,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -2797,7 +2797,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -2855,7 +2855,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -2913,7 +2913,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -2971,7 +2971,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -3030,7 +3030,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -3094,7 +3094,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -3152,7 +3152,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -3210,7 +3210,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -3268,7 +3268,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -3326,7 +3326,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -3384,7 +3384,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -3442,7 +3442,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -3500,7 +3500,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -3559,7 +3559,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -3619,7 +3619,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -3674,7 +3674,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -3732,7 +3732,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -3790,7 +3790,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -3848,7 +3848,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -3918,7 +3918,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -3977,7 +3977,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -4048,7 +4048,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -4118,7 +4118,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -4177,7 +4177,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -4233,7 +4233,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -4292,7 +4292,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -4359,7 +4359,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -4418,7 +4418,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -4505,7 +4505,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -4592,7 +4592,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -4663,7 +4663,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -4722,7 +4722,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/error_recovery/keyword_named_class_methods.dart.intertwined.expect b/pkg/front_end/parser_testcases/error_recovery/keyword_named_class_methods.dart.intertwined.expect
index 04c0792..36f1d49 100644
--- a/pkg/front_end/parser_testcases/error_recovery/keyword_named_class_methods.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/keyword_named_class_methods.dart.intertwined.expect
@@ -45,7 +45,7 @@
                   parseFormalParameters(abstract, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -56,7 +56,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -189,7 +189,7 @@
                   parseFormalParameters(as, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -200,7 +200,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -337,7 +337,7 @@
                   parseFormalParameters(assert, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -348,7 +348,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -472,7 +472,7 @@
                   parseFormalParameters(async, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -483,7 +483,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -616,7 +616,7 @@
                   parseFormalParameters(await, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -627,7 +627,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -767,7 +767,7 @@
                   parseFormalParameters(break, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -778,7 +778,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -946,7 +946,7 @@
                   parseFormalParameters(case, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -957,7 +957,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -1093,7 +1093,7 @@
                   parseFormalParameters(catch, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1104,7 +1104,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -1240,7 +1240,7 @@
                   parseFormalParameters(class, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1251,7 +1251,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -1387,7 +1387,7 @@
                   parseFormalParameters(const, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1398,7 +1398,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -1539,7 +1539,7 @@
                   parseFormalParameters(continue, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1550,7 +1550,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -1714,7 +1714,7 @@
                   parseFormalParameters(covariant, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1725,7 +1725,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -1862,7 +1862,7 @@
                   parseFormalParameters(default, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1873,7 +1873,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -2005,7 +2005,7 @@
                   parseFormalParameters(deferred, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -2016,7 +2016,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -2153,7 +2153,7 @@
                   parseFormalParameters(do, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -2164,7 +2164,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -2352,7 +2352,7 @@
                   parseFormalParameters(dynamic, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -2363,7 +2363,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -2500,7 +2500,7 @@
                   parseFormalParameters(else, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -2511,7 +2511,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -2697,7 +2697,7 @@
                   parseFormalParameters(enum, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -2708,7 +2708,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -2840,7 +2840,7 @@
                   parseFormalParameters(export, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -2851,7 +2851,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -2988,7 +2988,7 @@
                   parseFormalParameters(extends, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -2999,7 +2999,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -3131,7 +3131,7 @@
                   parseFormalParameters(extension, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -3142,7 +3142,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -3275,7 +3275,7 @@
                   parseFormalParameters(external, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -3286,7 +3286,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -3419,7 +3419,7 @@
                   parseFormalParameters(factory, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -3430,7 +3430,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -3567,7 +3567,7 @@
                   parseFormalParameters(false, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -3578,7 +3578,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -3709,7 +3709,7 @@
                   parseFormalParameters(final, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -3720,7 +3720,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -3948,7 +3948,7 @@
                   parseFormalParameters(finally, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -3959,7 +3959,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -4095,7 +4095,7 @@
                   parseFormalParameters(for, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -4106,7 +4106,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -4305,7 +4305,7 @@
                   parseFormalParameters(Function, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -4316,7 +4316,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -4450,7 +4450,7 @@
                   parseFormalParameters(get, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -4461,7 +4461,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -4594,7 +4594,7 @@
                   parseFormalParameters(hide, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -4605,7 +4605,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -4742,7 +4742,7 @@
                   parseFormalParameters(if, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -4753,7 +4753,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -4923,7 +4923,7 @@
                   parseFormalParameters(implements, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -4934,7 +4934,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -5067,7 +5067,7 @@
                   parseFormalParameters(import, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -5078,7 +5078,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -5215,7 +5215,7 @@
                   parseFormalParameters(in, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -5226,7 +5226,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -5358,7 +5358,7 @@
                   parseFormalParameters(inout, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -5369,7 +5369,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -5502,7 +5502,7 @@
                   parseFormalParameters(interface, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -5513,7 +5513,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -5650,7 +5650,7 @@
                   parseFormalParameters(is, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -5661,7 +5661,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -5825,7 +5825,7 @@
                   parseFormalParameters(late, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -5836,7 +5836,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -5969,7 +5969,7 @@
                   parseFormalParameters(library, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -5980,7 +5980,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -6113,7 +6113,7 @@
                   parseFormalParameters(mixin, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -6124,7 +6124,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -6257,7 +6257,7 @@
                   parseFormalParameters(native, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -6268,7 +6268,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -6405,7 +6405,7 @@
                   parseFormalParameters(new, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -6416,7 +6416,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -6558,7 +6558,7 @@
                   parseFormalParameters(null, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -6569,7 +6569,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -6696,7 +6696,7 @@
                   parseFormalParameters(of, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -6707,7 +6707,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -6840,7 +6840,7 @@
                   parseFormalParameters(on, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -6851,7 +6851,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -6986,7 +6986,7 @@
                   parseFormalParameters(operator, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -6997,7 +6997,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -7130,7 +7130,7 @@
                   parseFormalParameters(out, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -7141,7 +7141,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -7274,7 +7274,7 @@
                   parseFormalParameters(part, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -7285,7 +7285,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -7418,7 +7418,7 @@
                   parseFormalParameters(patch, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -7429,7 +7429,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -7562,7 +7562,7 @@
                   parseFormalParameters(required, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -7573,7 +7573,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -7710,7 +7710,7 @@
                   parseFormalParameters(rethrow, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -7721,7 +7721,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -7857,7 +7857,7 @@
                   parseFormalParameters(return, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -7868,7 +7868,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -7997,7 +7997,7 @@
                   parseFormalParameters(set, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -8008,7 +8008,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -8141,7 +8141,7 @@
                   parseFormalParameters(show, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -8152,7 +8152,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -8285,7 +8285,7 @@
                   parseFormalParameters(source, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -8296,7 +8296,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -8429,7 +8429,7 @@
                   parseFormalParameters(static, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -8440,7 +8440,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -8600,7 +8600,7 @@
                     parseFormalParameters(, MemberKind.NonStaticMethod)
                       parseFormalParametersRest((, MemberKind.NonStaticMethod)
                         listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                        parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                           parseMetadataStar(()
                             listener: beginMetadataStar(int)
                             listener: endMetadataStar(0)
@@ -8611,7 +8611,7 @@
                           ensureIdentifier(int, formalParameterDeclaration)
                             listener: handleIdentifier(x, formalParameterDeclaration)
                           listener: handleFormalParameterWithoutValue())
-                          listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                          listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                   parseInitializersOpt())
                     listener: handleNoInitializers()
@@ -8741,7 +8741,7 @@
                   parseFormalParameters(switch, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -8752,7 +8752,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -8931,7 +8931,7 @@
                   parseFormalParameters(sync, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -8942,7 +8942,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -9102,7 +9102,7 @@
                     parseFormalParameters(, MemberKind.NonStaticMethod)
                       parseFormalParametersRest((, MemberKind.NonStaticMethod)
                         listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                        parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                           parseMetadataStar(()
                             listener: beginMetadataStar(int)
                             listener: endMetadataStar(0)
@@ -9113,7 +9113,7 @@
                           ensureIdentifier(int, formalParameterDeclaration)
                             listener: handleIdentifier(x, formalParameterDeclaration)
                           listener: handleFormalParameterWithoutValue())
-                          listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                          listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                   parseInitializersOpt())
                     listener: handleNoInitializers()
@@ -9243,7 +9243,7 @@
                   parseFormalParameters(throw, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -9254,7 +9254,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -9385,7 +9385,7 @@
                   parseFormalParameters(true, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -9396,7 +9396,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -9527,7 +9527,7 @@
                   parseFormalParameters(try, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -9538,7 +9538,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -9708,7 +9708,7 @@
                   parseFormalParameters(typedef, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -9719,7 +9719,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -9856,7 +9856,7 @@
                   parseFormalParameters(var, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -9867,7 +9867,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -10095,7 +10095,7 @@
                   parseFormalParameters(void, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -10106,7 +10106,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -10335,7 +10335,7 @@
                   parseFormalParameters(while, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -10346,7 +10346,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -10520,7 +10520,7 @@
                   parseFormalParameters(with, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -10531,7 +10531,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -10663,7 +10663,7 @@
                   parseFormalParameters(yield, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -10674,7 +10674,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
diff --git a/pkg/front_end/parser_testcases/error_recovery/keyword_named_formal_parameter.dart.expect b/pkg/front_end/parser_testcases/error_recovery/keyword_named_formal_parameter.dart.expect
index a1fd276..fd5c4ec 100644
--- a/pkg/front_end/parser_testcases/error_recovery/keyword_named_formal_parameter.dart.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/keyword_named_formal_parameter.dart.expect
@@ -809,7 +809,7 @@
           handleType(int, null)
           handleIdentifier(abstract, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, abstract, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, abstract, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -966,7 +966,7 @@
           handleType(int, null)
           handleIdentifier(as, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, as, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, as, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -1124,7 +1124,7 @@
           handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'assert' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: assert}], assert, assert)
           handleIdentifier(assert, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, assert, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, assert, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -1286,7 +1286,7 @@
           handleType(int, null)
           handleIdentifier(async, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, async, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, async, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -1443,7 +1443,7 @@
           handleType(int, null)
           handleIdentifier(await, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, await, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, await, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -1601,7 +1601,7 @@
           handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'break' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: break}], break, break)
           handleIdentifier(break, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, break, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, break, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -1764,7 +1764,7 @@
           handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'case' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: case}], case, case)
           handleIdentifier(case, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, case, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, case, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -1927,7 +1927,7 @@
           handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'catch' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: catch}], catch, catch)
           handleIdentifier(catch, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, catch, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, catch, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -2090,7 +2090,7 @@
           handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'class' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: class}], class, class)
           handleIdentifier(class, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, class, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, class, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -2253,7 +2253,7 @@
           handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'const' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: const}], const, const)
           handleIdentifier(const, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, const, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, const, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -2416,7 +2416,7 @@
           handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'continue' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: continue}], continue, continue)
           handleIdentifier(continue, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, continue, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, continue, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -2578,7 +2578,7 @@
           handleType(int, null)
           handleIdentifier(covariant, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, covariant, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, covariant, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -2736,7 +2736,7 @@
           handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'default' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: default}], default, default)
           handleIdentifier(default, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, default, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, default, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -2898,7 +2898,7 @@
           handleType(int, null)
           handleIdentifier(deferred, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, deferred, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, deferred, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -3056,7 +3056,7 @@
           handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'do' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: do}], do, do)
           handleIdentifier(do, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, do, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, do, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -3218,7 +3218,7 @@
           handleType(int, null)
           handleIdentifier(dynamic, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, dynamic, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, dynamic, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -3376,7 +3376,7 @@
           handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'else' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: else}], else, else)
           handleIdentifier(else, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, else, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, else, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -3539,7 +3539,7 @@
           handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'enum' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: enum}], enum, enum)
           handleIdentifier(enum, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, enum, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, enum, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -3701,7 +3701,7 @@
           handleType(int, null)
           handleIdentifier(export, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, export, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, export, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -3859,7 +3859,7 @@
           handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'extends' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: extends}], extends, extends)
           handleIdentifier(extends, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, extends, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, extends, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -4021,7 +4021,7 @@
           handleType(int, null)
           handleIdentifier(extension, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, extension, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, extension, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -4178,7 +4178,7 @@
           handleType(int, null)
           handleIdentifier(external, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, external, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, external, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -4335,7 +4335,7 @@
           handleType(int, null)
           handleIdentifier(factory, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, factory, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, factory, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -4493,7 +4493,7 @@
           handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'false' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: false}], false, false)
           handleIdentifier(false, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, false, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, false, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -4656,7 +4656,7 @@
           handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'final' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: final}], final, final)
           handleIdentifier(final, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, final, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, final, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -4819,7 +4819,7 @@
           handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'finally' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: finally}], finally, finally)
           handleIdentifier(finally, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, finally, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, finally, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -4982,7 +4982,7 @@
           handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'for' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: for}], for, for)
           handleIdentifier(for, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, for, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, for, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -5144,7 +5144,7 @@
           handleType(int, null)
           handleIdentifier(Function, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, Function, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, Function, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -5301,7 +5301,7 @@
           handleType(int, null)
           handleIdentifier(get, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, get, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, get, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -5458,7 +5458,7 @@
           handleType(int, null)
           handleIdentifier(hide, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, hide, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, hide, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -5616,7 +5616,7 @@
           handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'if' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: if}], if, if)
           handleIdentifier(if, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, if, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, if, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -5778,7 +5778,7 @@
           handleType(int, null)
           handleIdentifier(implements, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, implements, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, implements, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -5935,7 +5935,7 @@
           handleType(int, null)
           handleIdentifier(import, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, import, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, import, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -6093,7 +6093,7 @@
           handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'in' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: in}], in, in)
           handleIdentifier(in, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, in, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, in, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -6255,7 +6255,7 @@
           handleType(int, null)
           handleIdentifier(inout, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, inout, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, inout, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -6412,7 +6412,7 @@
           handleType(int, null)
           handleIdentifier(interface, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, interface, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, interface, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -6570,7 +6570,7 @@
           handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'is' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: is}], is, is)
           handleIdentifier(is, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, is, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, is, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -6732,7 +6732,7 @@
           handleType(int, null)
           handleIdentifier(late, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, late, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, late, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -6889,7 +6889,7 @@
           handleType(int, null)
           handleIdentifier(library, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, library, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, library, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -7046,7 +7046,7 @@
           handleType(int, null)
           handleIdentifier(mixin, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, mixin, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, mixin, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -7203,7 +7203,7 @@
           handleType(int, null)
           handleIdentifier(native, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, native, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, native, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -7361,7 +7361,7 @@
           handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'new' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: new}], new, new)
           handleIdentifier(new, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, new, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, new, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -7524,7 +7524,7 @@
           handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'null' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: null}], null, null)
           handleIdentifier(null, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, null, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, null, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -7686,7 +7686,7 @@
           handleType(int, null)
           handleIdentifier(of, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, of, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, of, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -7843,7 +7843,7 @@
           handleType(int, null)
           handleIdentifier(on, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, on, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, on, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -8000,7 +8000,7 @@
           handleType(int, null)
           handleIdentifier(operator, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, operator, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, operator, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -8157,7 +8157,7 @@
           handleType(int, null)
           handleIdentifier(out, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, out, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, out, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -8314,7 +8314,7 @@
           handleType(int, null)
           handleIdentifier(part, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, part, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, part, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -8471,7 +8471,7 @@
           handleType(int, null)
           handleIdentifier(patch, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, patch, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, patch, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -8628,7 +8628,7 @@
           handleType(int, null)
           handleIdentifier(required, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, required, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, required, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -8786,7 +8786,7 @@
           handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'rethrow' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: rethrow}], rethrow, rethrow)
           handleIdentifier(rethrow, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, rethrow, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, rethrow, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -8949,7 +8949,7 @@
           handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'return' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: return}], return, return)
           handleIdentifier(return, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, return, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, return, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -9111,7 +9111,7 @@
           handleType(int, null)
           handleIdentifier(set, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, set, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, set, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -9268,7 +9268,7 @@
           handleType(int, null)
           handleIdentifier(show, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, show, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, show, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -9425,7 +9425,7 @@
           handleType(int, null)
           handleIdentifier(source, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, source, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, source, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -9582,7 +9582,7 @@
           handleType(int, null)
           handleIdentifier(static, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, static, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, static, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -9740,7 +9740,7 @@
           handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'super' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: super}], super, super)
           handleIdentifier(super, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, super, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, super, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -9903,7 +9903,7 @@
           handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'switch' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: switch}], switch, switch)
           handleIdentifier(switch, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, switch, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, switch, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -10065,7 +10065,7 @@
           handleType(int, null)
           handleIdentifier(sync, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, sync, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, sync, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -10223,7 +10223,7 @@
           handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'this' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: this}], this, this)
           handleIdentifier(this, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, this, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, this, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -10386,7 +10386,7 @@
           handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'throw' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: throw}], throw, throw)
           handleIdentifier(throw, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, throw, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, throw, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -10549,7 +10549,7 @@
           handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'true' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: true}], true, true)
           handleIdentifier(true, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, true, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, true, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -10712,7 +10712,7 @@
           handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'try' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: try}], try, try)
           handleIdentifier(try, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, try, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, try, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -10874,7 +10874,7 @@
           handleType(int, null)
           handleIdentifier(typedef, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, typedef, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, typedef, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -11032,7 +11032,7 @@
           handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'var' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: var}], var, var)
           handleIdentifier(var, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, var, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, var, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -11195,7 +11195,7 @@
           handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'void' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: void}], void, void)
           handleIdentifier(void, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, void, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, void, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -11358,7 +11358,7 @@
           handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'while' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: while}], while, while)
           handleIdentifier(while, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, while, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, while, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -11521,7 +11521,7 @@
           handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'with' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: with}], with, with)
           handleIdentifier(with, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, with, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, with, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -11683,7 +11683,7 @@
           handleType(int, null)
           handleIdentifier(yield, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, yield, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, yield, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/error_recovery/keyword_named_formal_parameter.dart.intertwined.expect b/pkg/front_end/parser_testcases/error_recovery/keyword_named_formal_parameter.dart.intertwined.expect
index af2dd41..92be491 100644
--- a/pkg/front_end/parser_testcases/error_recovery/keyword_named_formal_parameter.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/keyword_named_formal_parameter.dart.intertwined.expect
@@ -19,7 +19,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -31,7 +31,7 @@
                   inPlainSync()
                   listener: handleIdentifier(abstract, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, abstract, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, abstract, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -303,7 +303,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -315,7 +315,7 @@
                   inPlainSync()
                   listener: handleIdentifier(as, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, as, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, as, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -587,7 +587,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -600,7 +600,7 @@
                     listener: handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'assert' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: assert}], assert, assert)
                   listener: handleIdentifier(assert, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, assert, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, assert, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -877,7 +877,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -889,7 +889,7 @@
                   inPlainSync()
                   listener: handleIdentifier(async, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, async, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, async, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -1161,7 +1161,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -1173,7 +1173,7 @@
                   inPlainSync()
                   listener: handleIdentifier(await, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, await, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, await, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -1445,7 +1445,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -1458,7 +1458,7 @@
                     listener: handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'break' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: break}], break, break)
                   listener: handleIdentifier(break, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, break, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, break, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -1735,7 +1735,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -1748,7 +1748,7 @@
                     listener: handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'case' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: case}], case, case)
                   listener: handleIdentifier(case, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, case, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, case, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -2025,7 +2025,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -2038,7 +2038,7 @@
                     listener: handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'catch' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: catch}], catch, catch)
                   listener: handleIdentifier(catch, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, catch, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, catch, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -2315,7 +2315,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -2328,7 +2328,7 @@
                     listener: handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'class' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: class}], class, class)
                   listener: handleIdentifier(class, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, class, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, class, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -2605,7 +2605,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -2618,7 +2618,7 @@
                     listener: handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'const' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: const}], const, const)
                   listener: handleIdentifier(const, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, const, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, const, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -2895,7 +2895,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -2908,7 +2908,7 @@
                     listener: handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'continue' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: continue}], continue, continue)
                   listener: handleIdentifier(continue, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, continue, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, continue, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -3185,7 +3185,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -3197,7 +3197,7 @@
                   inPlainSync()
                   listener: handleIdentifier(covariant, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, covariant, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, covariant, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -3469,7 +3469,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -3482,7 +3482,7 @@
                     listener: handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'default' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: default}], default, default)
                   listener: handleIdentifier(default, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, default, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, default, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -3759,7 +3759,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -3771,7 +3771,7 @@
                   inPlainSync()
                   listener: handleIdentifier(deferred, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, deferred, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, deferred, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -4043,7 +4043,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -4056,7 +4056,7 @@
                     listener: handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'do' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: do}], do, do)
                   listener: handleIdentifier(do, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, do, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, do, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -4333,7 +4333,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -4345,7 +4345,7 @@
                   inPlainSync()
                   listener: handleIdentifier(dynamic, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, dynamic, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, dynamic, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -4617,7 +4617,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -4630,7 +4630,7 @@
                     listener: handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'else' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: else}], else, else)
                   listener: handleIdentifier(else, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, else, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, else, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -4907,7 +4907,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -4920,7 +4920,7 @@
                     listener: handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'enum' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: enum}], enum, enum)
                   listener: handleIdentifier(enum, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, enum, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, enum, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -5197,7 +5197,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -5209,7 +5209,7 @@
                   inPlainSync()
                   listener: handleIdentifier(export, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, export, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, export, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -5481,7 +5481,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -5494,7 +5494,7 @@
                     listener: handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'extends' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: extends}], extends, extends)
                   listener: handleIdentifier(extends, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, extends, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, extends, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -5771,7 +5771,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -5783,7 +5783,7 @@
                   inPlainSync()
                   listener: handleIdentifier(extension, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, extension, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, extension, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -6055,7 +6055,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -6067,7 +6067,7 @@
                   inPlainSync()
                   listener: handleIdentifier(external, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, external, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, external, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -6339,7 +6339,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -6351,7 +6351,7 @@
                   inPlainSync()
                   listener: handleIdentifier(factory, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, factory, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, factory, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -6623,7 +6623,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -6636,7 +6636,7 @@
                     listener: handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'false' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: false}], false, false)
                   listener: handleIdentifier(false, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, false, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, false, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -6913,7 +6913,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -6926,7 +6926,7 @@
                     listener: handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'final' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: final}], final, final)
                   listener: handleIdentifier(final, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, final, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, final, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -7203,7 +7203,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -7216,7 +7216,7 @@
                     listener: handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'finally' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: finally}], finally, finally)
                   listener: handleIdentifier(finally, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, finally, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, finally, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -7493,7 +7493,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -7506,7 +7506,7 @@
                     listener: handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'for' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: for}], for, for)
                   listener: handleIdentifier(for, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, for, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, for, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -7783,7 +7783,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -7795,7 +7795,7 @@
                   inPlainSync()
                   listener: handleIdentifier(Function, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, Function, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, Function, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -8067,7 +8067,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -8079,7 +8079,7 @@
                   inPlainSync()
                   listener: handleIdentifier(get, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, get, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, get, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -8351,7 +8351,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -8363,7 +8363,7 @@
                   inPlainSync()
                   listener: handleIdentifier(hide, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, hide, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, hide, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -8635,7 +8635,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -8648,7 +8648,7 @@
                     listener: handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'if' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: if}], if, if)
                   listener: handleIdentifier(if, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, if, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, if, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -8925,7 +8925,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -8937,7 +8937,7 @@
                   inPlainSync()
                   listener: handleIdentifier(implements, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, implements, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, implements, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -9209,7 +9209,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -9221,7 +9221,7 @@
                   inPlainSync()
                   listener: handleIdentifier(import, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, import, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, import, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -9493,7 +9493,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -9506,7 +9506,7 @@
                     listener: handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'in' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: in}], in, in)
                   listener: handleIdentifier(in, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, in, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, in, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -9783,7 +9783,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -9795,7 +9795,7 @@
                   inPlainSync()
                   listener: handleIdentifier(inout, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, inout, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, inout, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -10067,7 +10067,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -10079,7 +10079,7 @@
                   inPlainSync()
                   listener: handleIdentifier(interface, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, interface, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, interface, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -10351,7 +10351,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -10364,7 +10364,7 @@
                     listener: handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'is' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: is}], is, is)
                   listener: handleIdentifier(is, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, is, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, is, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -10641,7 +10641,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -10653,7 +10653,7 @@
                   inPlainSync()
                   listener: handleIdentifier(late, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, late, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, late, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -10925,7 +10925,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -10937,7 +10937,7 @@
                   inPlainSync()
                   listener: handleIdentifier(library, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, library, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, library, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -11209,7 +11209,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -11221,7 +11221,7 @@
                   inPlainSync()
                   listener: handleIdentifier(mixin, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, mixin, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, mixin, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -11493,7 +11493,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -11505,7 +11505,7 @@
                   inPlainSync()
                   listener: handleIdentifier(native, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, native, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, native, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -11777,7 +11777,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -11790,7 +11790,7 @@
                     listener: handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'new' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: new}], new, new)
                   listener: handleIdentifier(new, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, new, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, new, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -12067,7 +12067,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -12080,7 +12080,7 @@
                     listener: handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'null' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: null}], null, null)
                   listener: handleIdentifier(null, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, null, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, null, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -12357,7 +12357,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -12369,7 +12369,7 @@
                   inPlainSync()
                   listener: handleIdentifier(of, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, of, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, of, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -12641,7 +12641,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -12653,7 +12653,7 @@
                   inPlainSync()
                   listener: handleIdentifier(on, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, on, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, on, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -12925,7 +12925,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -12937,7 +12937,7 @@
                   inPlainSync()
                   listener: handleIdentifier(operator, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, operator, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, operator, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -13209,7 +13209,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -13221,7 +13221,7 @@
                   inPlainSync()
                   listener: handleIdentifier(out, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, out, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, out, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -13493,7 +13493,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -13505,7 +13505,7 @@
                   inPlainSync()
                   listener: handleIdentifier(part, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, part, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, part, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -13777,7 +13777,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -13789,7 +13789,7 @@
                   inPlainSync()
                   listener: handleIdentifier(patch, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, patch, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, patch, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -14061,7 +14061,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -14073,7 +14073,7 @@
                   inPlainSync()
                   listener: handleIdentifier(required, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, required, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, required, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -14345,7 +14345,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -14358,7 +14358,7 @@
                     listener: handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'rethrow' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: rethrow}], rethrow, rethrow)
                   listener: handleIdentifier(rethrow, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, rethrow, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, rethrow, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -14635,7 +14635,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -14648,7 +14648,7 @@
                     listener: handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'return' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: return}], return, return)
                   listener: handleIdentifier(return, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, return, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, return, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -14925,7 +14925,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -14937,7 +14937,7 @@
                   inPlainSync()
                   listener: handleIdentifier(set, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, set, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, set, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -15209,7 +15209,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -15221,7 +15221,7 @@
                   inPlainSync()
                   listener: handleIdentifier(show, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, show, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, show, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -15493,7 +15493,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -15505,7 +15505,7 @@
                   inPlainSync()
                   listener: handleIdentifier(source, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, source, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, source, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -15777,7 +15777,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -15789,7 +15789,7 @@
                   inPlainSync()
                   listener: handleIdentifier(static, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, static, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, static, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -16061,7 +16061,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -16074,7 +16074,7 @@
                     listener: handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'super' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: super}], super, super)
                   listener: handleIdentifier(super, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, super, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, super, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -16351,7 +16351,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -16364,7 +16364,7 @@
                     listener: handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'switch' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: switch}], switch, switch)
                   listener: handleIdentifier(switch, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, switch, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, switch, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -16641,7 +16641,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -16653,7 +16653,7 @@
                   inPlainSync()
                   listener: handleIdentifier(sync, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, sync, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, sync, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -16925,7 +16925,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -16938,7 +16938,7 @@
                     listener: handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'this' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: this}], this, this)
                   listener: handleIdentifier(this, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, this, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, this, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -17215,7 +17215,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -17228,7 +17228,7 @@
                     listener: handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'throw' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: throw}], throw, throw)
                   listener: handleIdentifier(throw, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, throw, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, throw, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -17505,7 +17505,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -17518,7 +17518,7 @@
                     listener: handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'true' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: true}], true, true)
                   listener: handleIdentifier(true, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, true, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, true, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -17795,7 +17795,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -17808,7 +17808,7 @@
                     listener: handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'try' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: try}], try, try)
                   listener: handleIdentifier(try, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, try, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, try, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -18085,7 +18085,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -18097,7 +18097,7 @@
                   inPlainSync()
                   listener: handleIdentifier(typedef, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, typedef, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, typedef, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -18369,7 +18369,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -18382,7 +18382,7 @@
                     listener: handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'var' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: var}], var, var)
                   listener: handleIdentifier(var, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, var, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, var, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -18659,7 +18659,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -18672,7 +18672,7 @@
                     listener: handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'void' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: void}], void, void)
                   listener: handleIdentifier(void, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, void, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, void, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -18949,7 +18949,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -18962,7 +18962,7 @@
                     listener: handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'while' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: while}], while, while)
                   listener: handleIdentifier(while, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, while, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, while, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -19239,7 +19239,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -19252,7 +19252,7 @@
                     listener: handleRecoverableError(Message[ExpectedIdentifierButGotKeyword, 'with' can't be used as an identifier because it's a keyword., Try renaming this to be an identifier that isn't a keyword., {lexeme: with}], with, with)
                   listener: handleIdentifier(with, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, with, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, with, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -19529,7 +19529,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -19541,7 +19541,7 @@
                   inPlainSync()
                   listener: handleIdentifier(yield, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, yield, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, yield, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/error_recovery/keyword_named_formal_parameter_prime.dart.expect b/pkg/front_end/parser_testcases/error_recovery/keyword_named_formal_parameter_prime.dart.expect
index e3ca5ec..ab33d55 100644
--- a/pkg/front_end/parser_testcases/error_recovery/keyword_named_formal_parameter_prime.dart.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/keyword_named_formal_parameter_prime.dart.expect
@@ -15,7 +15,7 @@
           handleType(int, null)
           handleIdentifier(abstractX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, abstractX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, abstractX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -172,7 +172,7 @@
           handleType(int, null)
           handleIdentifier(asX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, asX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, asX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -329,7 +329,7 @@
           handleType(int, null)
           handleIdentifier(assertX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, assertX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, assertX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -486,7 +486,7 @@
           handleType(int, null)
           handleIdentifier(asyncX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, asyncX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, asyncX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -643,7 +643,7 @@
           handleType(int, null)
           handleIdentifier(awaitX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, awaitX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, awaitX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -800,7 +800,7 @@
           handleType(int, null)
           handleIdentifier(breakX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, breakX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, breakX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -957,7 +957,7 @@
           handleType(int, null)
           handleIdentifier(caseX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, caseX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, caseX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -1114,7 +1114,7 @@
           handleType(int, null)
           handleIdentifier(catchX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, catchX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, catchX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -1271,7 +1271,7 @@
           handleType(int, null)
           handleIdentifier(classX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, classX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, classX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -1428,7 +1428,7 @@
           handleType(int, null)
           handleIdentifier(constX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, constX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, constX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -1585,7 +1585,7 @@
           handleType(int, null)
           handleIdentifier(continueX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, continueX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, continueX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -1742,7 +1742,7 @@
           handleType(int, null)
           handleIdentifier(covariantX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, covariantX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, covariantX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -1899,7 +1899,7 @@
           handleType(int, null)
           handleIdentifier(defaultX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, defaultX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, defaultX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -2056,7 +2056,7 @@
           handleType(int, null)
           handleIdentifier(deferredX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, deferredX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, deferredX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -2213,7 +2213,7 @@
           handleType(int, null)
           handleIdentifier(doX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, doX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, doX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -2370,7 +2370,7 @@
           handleType(int, null)
           handleIdentifier(dynamicX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, dynamicX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, dynamicX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -2527,7 +2527,7 @@
           handleType(int, null)
           handleIdentifier(elseX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, elseX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, elseX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -2684,7 +2684,7 @@
           handleType(int, null)
           handleIdentifier(enumX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, enumX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, enumX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -2841,7 +2841,7 @@
           handleType(int, null)
           handleIdentifier(exportX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, exportX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, exportX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -2998,7 +2998,7 @@
           handleType(int, null)
           handleIdentifier(extendsX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, extendsX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, extendsX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -3155,7 +3155,7 @@
           handleType(int, null)
           handleIdentifier(extensionX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, extensionX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, extensionX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -3312,7 +3312,7 @@
           handleType(int, null)
           handleIdentifier(externalX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, externalX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, externalX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -3469,7 +3469,7 @@
           handleType(int, null)
           handleIdentifier(factoryX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, factoryX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, factoryX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -3626,7 +3626,7 @@
           handleType(int, null)
           handleIdentifier(falseX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, falseX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, falseX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -3783,7 +3783,7 @@
           handleType(int, null)
           handleIdentifier(finalX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, finalX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, finalX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -3940,7 +3940,7 @@
           handleType(int, null)
           handleIdentifier(finallyX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, finallyX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, finallyX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -4097,7 +4097,7 @@
           handleType(int, null)
           handleIdentifier(forX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, forX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, forX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -4254,7 +4254,7 @@
           handleType(int, null)
           handleIdentifier(FunctionX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, FunctionX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, FunctionX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -4411,7 +4411,7 @@
           handleType(int, null)
           handleIdentifier(getX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, getX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, getX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -4568,7 +4568,7 @@
           handleType(int, null)
           handleIdentifier(hideX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, hideX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, hideX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -4725,7 +4725,7 @@
           handleType(int, null)
           handleIdentifier(ifX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, ifX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, ifX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -4882,7 +4882,7 @@
           handleType(int, null)
           handleIdentifier(implementsX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, implementsX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, implementsX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -5039,7 +5039,7 @@
           handleType(int, null)
           handleIdentifier(importX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, importX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, importX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -5196,7 +5196,7 @@
           handleType(int, null)
           handleIdentifier(inX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, inX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, inX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -5353,7 +5353,7 @@
           handleType(int, null)
           handleIdentifier(inoutX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, inoutX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, inoutX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -5510,7 +5510,7 @@
           handleType(int, null)
           handleIdentifier(interfaceX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, interfaceX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, interfaceX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -5667,7 +5667,7 @@
           handleType(int, null)
           handleIdentifier(isX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, isX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, isX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -5824,7 +5824,7 @@
           handleType(int, null)
           handleIdentifier(lateX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, lateX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, lateX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -5981,7 +5981,7 @@
           handleType(int, null)
           handleIdentifier(libraryX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, libraryX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, libraryX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -6138,7 +6138,7 @@
           handleType(int, null)
           handleIdentifier(mixinX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, mixinX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, mixinX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -6295,7 +6295,7 @@
           handleType(int, null)
           handleIdentifier(nativeX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, nativeX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, nativeX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -6452,7 +6452,7 @@
           handleType(int, null)
           handleIdentifier(newX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, newX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, newX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -6609,7 +6609,7 @@
           handleType(int, null)
           handleIdentifier(nullX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, nullX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, nullX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -6766,7 +6766,7 @@
           handleType(int, null)
           handleIdentifier(ofX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, ofX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, ofX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -6923,7 +6923,7 @@
           handleType(int, null)
           handleIdentifier(onX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, onX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, onX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -7080,7 +7080,7 @@
           handleType(int, null)
           handleIdentifier(operatorX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, operatorX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, operatorX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -7237,7 +7237,7 @@
           handleType(int, null)
           handleIdentifier(outX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, outX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, outX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -7394,7 +7394,7 @@
           handleType(int, null)
           handleIdentifier(partX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, partX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, partX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -7551,7 +7551,7 @@
           handleType(int, null)
           handleIdentifier(patchX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, patchX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, patchX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -7708,7 +7708,7 @@
           handleType(int, null)
           handleIdentifier(requiredX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, requiredX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, requiredX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -7865,7 +7865,7 @@
           handleType(int, null)
           handleIdentifier(rethrowX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, rethrowX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, rethrowX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -8022,7 +8022,7 @@
           handleType(int, null)
           handleIdentifier(returnX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, returnX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, returnX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -8179,7 +8179,7 @@
           handleType(int, null)
           handleIdentifier(setX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, setX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, setX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -8336,7 +8336,7 @@
           handleType(int, null)
           handleIdentifier(showX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, showX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, showX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -8493,7 +8493,7 @@
           handleType(int, null)
           handleIdentifier(sourceX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, sourceX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, sourceX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -8650,7 +8650,7 @@
           handleType(int, null)
           handleIdentifier(staticX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, staticX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, staticX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -8807,7 +8807,7 @@
           handleType(int, null)
           handleIdentifier(superX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, superX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, superX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -8964,7 +8964,7 @@
           handleType(int, null)
           handleIdentifier(switchX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, switchX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, switchX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -9121,7 +9121,7 @@
           handleType(int, null)
           handleIdentifier(syncX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, syncX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, syncX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -9278,7 +9278,7 @@
           handleType(int, null)
           handleIdentifier(thisX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, thisX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, thisX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -9435,7 +9435,7 @@
           handleType(int, null)
           handleIdentifier(throwX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, throwX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, throwX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -9592,7 +9592,7 @@
           handleType(int, null)
           handleIdentifier(trueX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, trueX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, trueX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -9749,7 +9749,7 @@
           handleType(int, null)
           handleIdentifier(tryX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, tryX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, tryX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -9906,7 +9906,7 @@
           handleType(int, null)
           handleIdentifier(typedefX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, typedefX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, typedefX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -10063,7 +10063,7 @@
           handleType(int, null)
           handleIdentifier(varX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, varX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, varX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -10220,7 +10220,7 @@
           handleType(int, null)
           handleIdentifier(voidX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, voidX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, voidX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -10377,7 +10377,7 @@
           handleType(int, null)
           handleIdentifier(whileX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, whileX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, whileX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -10534,7 +10534,7 @@
           handleType(int, null)
           handleIdentifier(withX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, withX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, withX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -10691,7 +10691,7 @@
           handleType(int, null)
           handleIdentifier(yieldX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, yieldX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, yieldX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/error_recovery/keyword_named_formal_parameter_prime.dart.intertwined.expect b/pkg/front_end/parser_testcases/error_recovery/keyword_named_formal_parameter_prime.dart.intertwined.expect
index ce4b7a3..d4fea1c 100644
--- a/pkg/front_end/parser_testcases/error_recovery/keyword_named_formal_parameter_prime.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/keyword_named_formal_parameter_prime.dart.intertwined.expect
@@ -19,7 +19,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -30,7 +30,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(abstractX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, abstractX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, abstractX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -297,7 +297,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -308,7 +308,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(asX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, asX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, asX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -575,7 +575,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -586,7 +586,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(assertX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, assertX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, assertX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -853,7 +853,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -864,7 +864,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(asyncX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, asyncX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, asyncX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -1131,7 +1131,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -1142,7 +1142,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(awaitX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, awaitX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, awaitX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -1409,7 +1409,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -1420,7 +1420,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(breakX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, breakX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, breakX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -1687,7 +1687,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -1698,7 +1698,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(caseX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, caseX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, caseX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -1965,7 +1965,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -1976,7 +1976,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(catchX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, catchX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, catchX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -2243,7 +2243,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -2254,7 +2254,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(classX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, classX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, classX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -2521,7 +2521,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -2532,7 +2532,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(constX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, constX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, constX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -2799,7 +2799,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -2810,7 +2810,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(continueX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, continueX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, continueX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -3077,7 +3077,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -3088,7 +3088,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(covariantX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, covariantX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, covariantX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -3355,7 +3355,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -3366,7 +3366,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(defaultX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, defaultX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, defaultX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -3633,7 +3633,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -3644,7 +3644,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(deferredX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, deferredX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, deferredX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -3911,7 +3911,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -3922,7 +3922,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(doX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, doX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, doX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -4189,7 +4189,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -4200,7 +4200,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(dynamicX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, dynamicX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, dynamicX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -4467,7 +4467,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -4478,7 +4478,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(elseX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, elseX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, elseX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -4745,7 +4745,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -4756,7 +4756,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(enumX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, enumX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, enumX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -5023,7 +5023,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -5034,7 +5034,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(exportX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, exportX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, exportX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -5301,7 +5301,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -5312,7 +5312,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(extendsX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, extendsX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, extendsX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -5579,7 +5579,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -5590,7 +5590,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(extensionX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, extensionX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, extensionX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -5857,7 +5857,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -5868,7 +5868,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(externalX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, externalX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, externalX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -6135,7 +6135,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -6146,7 +6146,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(factoryX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, factoryX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, factoryX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -6413,7 +6413,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -6424,7 +6424,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(falseX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, falseX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, falseX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -6691,7 +6691,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -6702,7 +6702,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(finalX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, finalX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, finalX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -6969,7 +6969,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -6980,7 +6980,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(finallyX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, finallyX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, finallyX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -7247,7 +7247,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -7258,7 +7258,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(forX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, forX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, forX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -7525,7 +7525,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -7536,7 +7536,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(FunctionX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, FunctionX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, FunctionX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -7803,7 +7803,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -7814,7 +7814,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(getX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, getX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, getX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -8081,7 +8081,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -8092,7 +8092,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(hideX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, hideX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, hideX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -8359,7 +8359,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -8370,7 +8370,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(ifX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, ifX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, ifX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -8637,7 +8637,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -8648,7 +8648,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(implementsX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, implementsX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, implementsX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -8915,7 +8915,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -8926,7 +8926,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(importX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, importX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, importX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -9193,7 +9193,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -9204,7 +9204,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(inX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, inX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, inX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -9471,7 +9471,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -9482,7 +9482,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(inoutX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, inoutX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, inoutX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -9749,7 +9749,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -9760,7 +9760,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(interfaceX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, interfaceX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, interfaceX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -10027,7 +10027,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -10038,7 +10038,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(isX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, isX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, isX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -10305,7 +10305,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -10316,7 +10316,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(lateX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, lateX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, lateX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -10583,7 +10583,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -10594,7 +10594,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(libraryX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, libraryX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, libraryX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -10861,7 +10861,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -10872,7 +10872,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(mixinX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, mixinX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, mixinX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -11139,7 +11139,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -11150,7 +11150,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(nativeX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, nativeX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, nativeX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -11417,7 +11417,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -11428,7 +11428,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(newX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, newX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, newX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -11695,7 +11695,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -11706,7 +11706,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(nullX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, nullX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, nullX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -11973,7 +11973,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -11984,7 +11984,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(ofX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, ofX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, ofX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -12251,7 +12251,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -12262,7 +12262,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(onX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, onX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, onX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -12529,7 +12529,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -12540,7 +12540,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(operatorX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, operatorX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, operatorX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -12807,7 +12807,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -12818,7 +12818,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(outX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, outX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, outX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -13085,7 +13085,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -13096,7 +13096,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(partX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, partX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, partX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -13363,7 +13363,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -13374,7 +13374,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(patchX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, patchX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, patchX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -13641,7 +13641,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -13652,7 +13652,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(requiredX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, requiredX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, requiredX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -13919,7 +13919,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -13930,7 +13930,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(rethrowX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, rethrowX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, rethrowX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -14197,7 +14197,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -14208,7 +14208,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(returnX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, returnX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, returnX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -14475,7 +14475,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -14486,7 +14486,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(setX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, setX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, setX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -14753,7 +14753,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -14764,7 +14764,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(showX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, showX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, showX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -15031,7 +15031,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -15042,7 +15042,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(sourceX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, sourceX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, sourceX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -15309,7 +15309,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -15320,7 +15320,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(staticX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, staticX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, staticX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -15587,7 +15587,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -15598,7 +15598,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(superX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, superX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, superX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -15865,7 +15865,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -15876,7 +15876,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(switchX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, switchX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, switchX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -16143,7 +16143,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -16154,7 +16154,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(syncX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, syncX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, syncX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -16421,7 +16421,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -16432,7 +16432,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(thisX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, thisX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, thisX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -16699,7 +16699,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -16710,7 +16710,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(throwX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, throwX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, throwX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -16977,7 +16977,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -16988,7 +16988,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(trueX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, trueX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, trueX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -17255,7 +17255,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -17266,7 +17266,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(tryX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, tryX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, tryX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -17533,7 +17533,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -17544,7 +17544,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(typedefX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, typedefX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, typedefX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -17811,7 +17811,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -17822,7 +17822,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(varX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, varX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, varX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -18089,7 +18089,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -18100,7 +18100,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(voidX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, voidX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, voidX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -18367,7 +18367,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -18378,7 +18378,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(whileX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, whileX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, whileX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -18645,7 +18645,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -18656,7 +18656,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(withX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, withX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, withX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -18923,7 +18923,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -18934,7 +18934,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(yieldX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, yieldX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, yieldX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/error_recovery/keyword_named_formal_parameter_start_of_next_top_level.dart.expect b/pkg/front_end/parser_testcases/error_recovery/keyword_named_formal_parameter_start_of_next_top_level.dart.expect
index 3867cc6..eb31b03 100644
--- a/pkg/front_end/parser_testcases/error_recovery/keyword_named_formal_parameter_start_of_next_top_level.dart.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/keyword_named_formal_parameter_start_of_next_top_level.dart.expect
@@ -23,7 +23,7 @@
           handleNoType(()
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue(class)
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       handleRecoverableError(Message[ExpectedFunctionBody, Expected a function body, but got 'class'., null, {lexeme: class}], class, class)
diff --git a/pkg/front_end/parser_testcases/error_recovery/keyword_named_formal_parameter_start_of_next_top_level.dart.intertwined.expect b/pkg/front_end/parser_testcases/error_recovery/keyword_named_formal_parameter_start_of_next_top_level.dart.intertwined.expect
index 1a5f237..c90c0c6 100644
--- a/pkg/front_end/parser_testcases/error_recovery/keyword_named_formal_parameter_start_of_next_top_level.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/keyword_named_formal_parameter_start_of_next_top_level.dart.intertwined.expect
@@ -20,7 +20,7 @@
           parseFormalParameters(f, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(x)
                   listener: endMetadataStar(0)
@@ -29,7 +29,7 @@
                 ensureIdentifier((, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue(class)
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               rewriter()
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
diff --git a/pkg/front_end/parser_testcases/error_recovery/keyword_named_top_level_methods.dart.expect b/pkg/front_end/parser_testcases/error_recovery/keyword_named_top_level_methods.dart.expect
index bd52e60..02db7c4 100644
--- a/pkg/front_end/parser_testcases/error_recovery/keyword_named_top_level_methods.dart.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/keyword_named_top_level_methods.dart.expect
@@ -483,7 +483,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -540,7 +540,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -598,7 +598,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -653,7 +653,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -710,7 +710,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -768,7 +768,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -832,7 +832,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -891,7 +891,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -950,7 +950,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -1009,7 +1009,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -1072,7 +1072,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -1135,7 +1135,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -1193,7 +1193,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -1251,7 +1251,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -1309,7 +1309,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -1382,7 +1382,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -1440,7 +1440,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -1509,7 +1509,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -1567,7 +1567,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -1625,7 +1625,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -1683,7 +1683,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -1740,7 +1740,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -1797,7 +1797,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -1855,7 +1855,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -1913,7 +1913,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -1999,7 +1999,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -2058,7 +2058,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -2136,7 +2136,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -2193,7 +2193,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -2250,7 +2250,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -2308,7 +2308,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -2377,7 +2377,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -2434,7 +2434,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -2492,7 +2492,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -2550,7 +2550,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -2607,7 +2607,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -2665,7 +2665,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -2732,7 +2732,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -2789,7 +2789,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -2846,7 +2846,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -2903,7 +2903,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -2961,7 +2961,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -3024,7 +3024,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -3081,7 +3081,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -3138,7 +3138,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -3195,7 +3195,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -3252,7 +3252,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -3309,7 +3309,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -3366,7 +3366,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -3423,7 +3423,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -3481,7 +3481,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -3540,7 +3540,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -3594,7 +3594,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -3651,7 +3651,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -3708,7 +3708,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -3765,7 +3765,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -3823,7 +3823,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -3881,7 +3881,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -3951,7 +3951,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -4009,7 +4009,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -4067,7 +4067,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -4122,7 +4122,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -4180,7 +4180,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -4246,7 +4246,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -4304,7 +4304,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -4390,7 +4390,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -4476,7 +4476,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -4546,7 +4546,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -4604,7 +4604,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/error_recovery/keyword_named_top_level_methods.dart.intertwined.expect b/pkg/front_end/parser_testcases/error_recovery/keyword_named_top_level_methods.dart.intertwined.expect
index 91af5fa..1db298e 100644
--- a/pkg/front_end/parser_testcases/error_recovery/keyword_named_top_level_methods.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/keyword_named_top_level_methods.dart.intertwined.expect
@@ -21,7 +21,7 @@
           parseFormalParameters(abstract, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -32,7 +32,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -161,7 +161,7 @@
           parseFormalParameters(as, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -172,7 +172,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -305,7 +305,7 @@
           parseFormalParameters(assert, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -316,7 +316,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -436,7 +436,7 @@
           parseFormalParameters(async, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -447,7 +447,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -576,7 +576,7 @@
           parseFormalParameters(await, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -587,7 +587,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -723,7 +723,7 @@
           parseFormalParameters(break, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -734,7 +734,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -898,7 +898,7 @@
           parseFormalParameters(case, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -909,7 +909,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -1041,7 +1041,7 @@
           parseFormalParameters(catch, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -1052,7 +1052,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -1184,7 +1184,7 @@
           parseFormalParameters(class, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -1195,7 +1195,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -1327,7 +1327,7 @@
           parseFormalParameters(const, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -1338,7 +1338,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -1475,7 +1475,7 @@
           parseFormalParameters(continue, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -1486,7 +1486,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -1646,7 +1646,7 @@
           parseFormalParameters(covariant, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -1657,7 +1657,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -1790,7 +1790,7 @@
           parseFormalParameters(default, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -1801,7 +1801,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -1929,7 +1929,7 @@
           parseFormalParameters(deferred, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -1940,7 +1940,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -2073,7 +2073,7 @@
           parseFormalParameters(do, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -2084,7 +2084,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -2268,7 +2268,7 @@
           parseFormalParameters(dynamic, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -2279,7 +2279,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -2412,7 +2412,7 @@
           parseFormalParameters(else, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -2423,7 +2423,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -2605,7 +2605,7 @@
           parseFormalParameters(enum, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -2616,7 +2616,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -2744,7 +2744,7 @@
           parseFormalParameters(export, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -2755,7 +2755,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -2888,7 +2888,7 @@
           parseFormalParameters(extends, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -2899,7 +2899,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -3027,7 +3027,7 @@
           parseFormalParameters(extension, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -3038,7 +3038,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -3167,7 +3167,7 @@
           parseFormalParameters(external, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -3178,7 +3178,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -3307,7 +3307,7 @@
           parseFormalParameters(factory, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -3318,7 +3318,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -3451,7 +3451,7 @@
           parseFormalParameters(false, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -3462,7 +3462,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -3589,7 +3589,7 @@
           parseFormalParameters(final, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -3600,7 +3600,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -3824,7 +3824,7 @@
           parseFormalParameters(finally, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -3835,7 +3835,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -3967,7 +3967,7 @@
           parseFormalParameters(for, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -3978,7 +3978,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -4173,7 +4173,7 @@
           parseFormalParameters(Function, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -4184,7 +4184,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -4313,7 +4313,7 @@
           parseFormalParameters(get, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -4324,7 +4324,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -4453,7 +4453,7 @@
           parseFormalParameters(hide, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -4464,7 +4464,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -4597,7 +4597,7 @@
           parseFormalParameters(if, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -4608,7 +4608,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -4774,7 +4774,7 @@
           parseFormalParameters(implements, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -4785,7 +4785,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -4914,7 +4914,7 @@
           parseFormalParameters(import, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -4925,7 +4925,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -5058,7 +5058,7 @@
           parseFormalParameters(in, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -5069,7 +5069,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -5197,7 +5197,7 @@
           parseFormalParameters(inout, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -5208,7 +5208,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -5337,7 +5337,7 @@
           parseFormalParameters(interface, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -5348,7 +5348,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -5481,7 +5481,7 @@
           parseFormalParameters(is, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -5492,7 +5492,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -5652,7 +5652,7 @@
           parseFormalParameters(late, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -5663,7 +5663,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -5792,7 +5792,7 @@
           parseFormalParameters(library, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -5803,7 +5803,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -5932,7 +5932,7 @@
           parseFormalParameters(mixin, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -5943,7 +5943,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -6072,7 +6072,7 @@
           parseFormalParameters(native, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -6083,7 +6083,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -6216,7 +6216,7 @@
           parseFormalParameters(new, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -6227,7 +6227,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -6365,7 +6365,7 @@
           parseFormalParameters(null, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -6376,7 +6376,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -6499,7 +6499,7 @@
           parseFormalParameters(of, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -6510,7 +6510,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -6639,7 +6639,7 @@
           parseFormalParameters(on, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -6650,7 +6650,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -6779,7 +6779,7 @@
           parseFormalParameters(operator, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -6790,7 +6790,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -6919,7 +6919,7 @@
           parseFormalParameters(out, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -6930,7 +6930,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -7059,7 +7059,7 @@
           parseFormalParameters(part, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -7070,7 +7070,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -7199,7 +7199,7 @@
           parseFormalParameters(patch, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -7210,7 +7210,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -7339,7 +7339,7 @@
           parseFormalParameters(required, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -7350,7 +7350,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -7483,7 +7483,7 @@
           parseFormalParameters(rethrow, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -7494,7 +7494,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -7626,7 +7626,7 @@
           parseFormalParameters(return, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -7637,7 +7637,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -7761,7 +7761,7 @@
           parseFormalParameters(set, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -7772,7 +7772,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -7901,7 +7901,7 @@
           parseFormalParameters(show, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -7912,7 +7912,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -8041,7 +8041,7 @@
           parseFormalParameters(source, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -8052,7 +8052,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -8181,7 +8181,7 @@
           parseFormalParameters(static, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -8192,7 +8192,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -8323,7 +8323,7 @@
           parseFormalParameters(super, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -8334,7 +8334,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -8460,7 +8460,7 @@
           parseFormalParameters(switch, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -8471,7 +8471,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -8646,7 +8646,7 @@
           parseFormalParameters(sync, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -8657,7 +8657,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -8788,7 +8788,7 @@
           parseFormalParameters(this, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -8799,7 +8799,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -8925,7 +8925,7 @@
           parseFormalParameters(throw, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -8936,7 +8936,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -9063,7 +9063,7 @@
           parseFormalParameters(true, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -9074,7 +9074,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -9201,7 +9201,7 @@
           parseFormalParameters(try, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -9212,7 +9212,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -9378,7 +9378,7 @@
           parseFormalParameters(typedef, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -9389,7 +9389,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -9522,7 +9522,7 @@
           parseFormalParameters(var, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -9533,7 +9533,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -9757,7 +9757,7 @@
           parseFormalParameters(void, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -9768,7 +9768,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -9993,7 +9993,7 @@
           parseFormalParameters(while, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -10004,7 +10004,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -10174,7 +10174,7 @@
           parseFormalParameters(with, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -10185,7 +10185,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -10313,7 +10313,7 @@
           parseFormalParameters(yield, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -10324,7 +10324,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/error_recovery/method_called_with.dart.expect b/pkg/front_end/parser_testcases/error_recovery/method_called_with.dart.expect
index e2047f3..4499d3c 100644
--- a/pkg/front_end/parser_testcases/error_recovery/method_called_with.dart.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/method_called_with.dart.expect
@@ -103,7 +103,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/error_recovery/method_called_with.dart.intertwined.expect b/pkg/front_end/parser_testcases/error_recovery/method_called_with.dart.intertwined.expect
index 6934455..7cfe30a 100644
--- a/pkg/front_end/parser_testcases/error_recovery/method_called_with.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/method_called_with.dart.intertwined.expect
@@ -159,7 +159,7 @@
                   parseFormalParameters(with, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -170,7 +170,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
diff --git a/pkg/front_end/parser_testcases/error_recovery/method_called_with_prime.dart.expect b/pkg/front_end/parser_testcases/error_recovery/method_called_with_prime.dart.expect
index 5eeaf82..fbd7076 100644
--- a/pkg/front_end/parser_testcases/error_recovery/method_called_with_prime.dart.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/method_called_with_prime.dart.expect
@@ -73,7 +73,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/error_recovery/method_called_with_prime.dart.intertwined.expect b/pkg/front_end/parser_testcases/error_recovery/method_called_with_prime.dart.intertwined.expect
index e653b4e..d1d6c10 100644
--- a/pkg/front_end/parser_testcases/error_recovery/method_called_with_prime.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/method_called_with_prime.dart.intertwined.expect
@@ -143,7 +143,7 @@
                   parseFormalParameters(With, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -154,7 +154,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
diff --git a/pkg/front_end/parser_testcases/error_recovery/utf_16_le_content.crash_dart.expect b/pkg/front_end/parser_testcases/error_recovery/utf_16_le_content.crash_dart.expect
index 3af857b..d0fd8f1 100644
--- a/pkg/front_end/parser_testcases/error_recovery/utf_16_le_content.crash_dart.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/utf_16_le_content.crash_dart.expect
Binary files differ
diff --git a/pkg/front_end/parser_testcases/error_recovery/utf_16_le_content.crash_dart.intertwined.expect b/pkg/front_end/parser_testcases/error_recovery/utf_16_le_content.crash_dart.intertwined.expect
index a2da381..35df62b 100644
--- a/pkg/front_end/parser_testcases/error_recovery/utf_16_le_content.crash_dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/error_recovery/utf_16_le_content.crash_dart.intertwined.expect
@@ -124,7 +124,7 @@
           parseFormalParameters(t, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(c)
                   listener: endMetadataStar(0)
@@ -133,7 +133,7 @@
                 ensureIdentifier((, formalParameterDeclaration)
                   listener: handleIdentifier(c, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, c, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, c, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/extension_named_type.dart.expect b/pkg/front_end/parser_testcases/extension_named_type.dart.expect
index 1744160..f9bf0cd 100644
--- a/pkg/front_end/parser_testcases/extension_named_type.dart.expect
+++ b/pkg/front_end/parser_testcases/extension_named_type.dart.expect
@@ -58,7 +58,7 @@
           handleType(A, null)
           handleIdentifier(a, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, a, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, a, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       handleIdentifier(type, expression)
diff --git a/pkg/front_end/parser_testcases/extension_named_type.dart.intertwined.expect b/pkg/front_end/parser_testcases/extension_named_type.dart.intertwined.expect
index 06ea190..59564b1 100644
--- a/pkg/front_end/parser_testcases/extension_named_type.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/extension_named_type.dart.intertwined.expect
@@ -98,7 +98,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(A)
                   listener: endMetadataStar(0)
@@ -109,7 +109,7 @@
                 ensureIdentifier(A, formalParameterDeclaration)
                   listener: handleIdentifier(a, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, a, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, a, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/extensions/covariant.dart.expect b/pkg/front_end/parser_testcases/extensions/covariant.dart.expect
index f37431c..dab74ca 100644
--- a/pkg/front_end/parser_testcases/extensions/covariant.dart.expect
+++ b/pkg/front_end/parser_testcases/extensions/covariant.dart.expect
@@ -64,7 +64,7 @@
                 handleType(A, null)
                 handleIdentifier(child, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, child, null, null, FormalParameterKind.mandatory, MemberKind.ExtensionNonStaticMethod)
+              endFormalParameter(null, null, null, child, null, null, FormalParameterKind.requiredPositional, MemberKind.ExtensionNonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.ExtensionNonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/extensions/covariant.dart.intertwined.expect b/pkg/front_end/parser_testcases/extensions/covariant.dart.intertwined.expect
index 835d04c..50dd4c4 100644
--- a/pkg/front_end/parser_testcases/extensions/covariant.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/extensions/covariant.dart.intertwined.expect
@@ -93,7 +93,7 @@
                 parseFormalParameters(addChild, MemberKind.ExtensionNonStaticMethod)
                   parseFormalParametersRest((, MemberKind.ExtensionNonStaticMethod)
                     listener: beginFormalParameters((, MemberKind.ExtensionNonStaticMethod)
-                    parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.ExtensionNonStaticMethod)
+                    parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.ExtensionNonStaticMethod)
                       parseMetadataStar(()
                         listener: beginMetadataStar(covariant)
                         listener: endMetadataStar(0)
@@ -106,7 +106,7 @@
                       ensureIdentifier(A, formalParameterDeclaration)
                         listener: handleIdentifier(child, formalParameterDeclaration)
                       listener: handleFormalParameterWithoutValue())
-                      listener: endFormalParameter(null, null, null, child, null, null, FormalParameterKind.mandatory, MemberKind.ExtensionNonStaticMethod)
+                      listener: endFormalParameter(null, null, null, child, null, null, FormalParameterKind.requiredPositional, MemberKind.ExtensionNonStaticMethod)
                     listener: endFormalParameters(1, (, ), MemberKind.ExtensionNonStaticMethod)
               parseInitializersOpt())
                 listener: handleNoInitializers()
diff --git a/pkg/front_end/parser_testcases/extensions/not_covariant.dart.expect b/pkg/front_end/parser_testcases/extensions/not_covariant.dart.expect
index 7c25b4c..111aade 100644
--- a/pkg/front_end/parser_testcases/extensions/not_covariant.dart.expect
+++ b/pkg/front_end/parser_testcases/extensions/not_covariant.dart.expect
@@ -57,7 +57,7 @@
                 handleType(A, null)
                 handleIdentifier(child, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, child, null, null, FormalParameterKind.mandatory, MemberKind.ExtensionNonStaticMethod)
+              endFormalParameter(null, null, null, child, null, null, FormalParameterKind.requiredPositional, MemberKind.ExtensionNonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.ExtensionNonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/extensions/not_covariant.dart.intertwined.expect b/pkg/front_end/parser_testcases/extensions/not_covariant.dart.intertwined.expect
index d0869ba..0a9e526 100644
--- a/pkg/front_end/parser_testcases/extensions/not_covariant.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/extensions/not_covariant.dart.intertwined.expect
@@ -93,7 +93,7 @@
                 parseFormalParameters(addChild, MemberKind.ExtensionNonStaticMethod)
                   parseFormalParametersRest((, MemberKind.ExtensionNonStaticMethod)
                     listener: beginFormalParameters((, MemberKind.ExtensionNonStaticMethod)
-                    parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.ExtensionNonStaticMethod)
+                    parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.ExtensionNonStaticMethod)
                       parseMetadataStar(()
                         listener: beginMetadataStar(A)
                         listener: endMetadataStar(0)
@@ -104,7 +104,7 @@
                       ensureIdentifier(A, formalParameterDeclaration)
                         listener: handleIdentifier(child, formalParameterDeclaration)
                       listener: handleFormalParameterWithoutValue())
-                      listener: endFormalParameter(null, null, null, child, null, null, FormalParameterKind.mandatory, MemberKind.ExtensionNonStaticMethod)
+                      listener: endFormalParameter(null, null, null, child, null, null, FormalParameterKind.requiredPositional, MemberKind.ExtensionNonStaticMethod)
                     listener: endFormalParameters(1, (, ), MemberKind.ExtensionNonStaticMethod)
               parseInitializersOpt())
                 listener: handleNoInitializers()
diff --git a/pkg/front_end/parser_testcases/extensions/static.dart.expect b/pkg/front_end/parser_testcases/extensions/static.dart.expect
index 932e894..c361540 100644
--- a/pkg/front_end/parser_testcases/extensions/static.dart.expect
+++ b/pkg/front_end/parser_testcases/extensions/static.dart.expect
@@ -57,7 +57,7 @@
                 handleType(A, null)
                 handleIdentifier(child, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, child, null, null, FormalParameterKind.mandatory, MemberKind.ExtensionStaticMethod)
+              endFormalParameter(null, null, null, child, null, null, FormalParameterKind.requiredPositional, MemberKind.ExtensionStaticMethod)
             endFormalParameters(1, (, ), MemberKind.ExtensionStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/extensions/static.dart.intertwined.expect b/pkg/front_end/parser_testcases/extensions/static.dart.intertwined.expect
index 57ce9e6..cef8fa7 100644
--- a/pkg/front_end/parser_testcases/extensions/static.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/extensions/static.dart.intertwined.expect
@@ -93,7 +93,7 @@
                 parseFormalParameters(addChild, MemberKind.ExtensionStaticMethod)
                   parseFormalParametersRest((, MemberKind.ExtensionStaticMethod)
                     listener: beginFormalParameters((, MemberKind.ExtensionStaticMethod)
-                    parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.ExtensionStaticMethod)
+                    parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.ExtensionStaticMethod)
                       parseMetadataStar(()
                         listener: beginMetadataStar(A)
                         listener: endMetadataStar(0)
@@ -104,7 +104,7 @@
                       ensureIdentifier(A, formalParameterDeclaration)
                         listener: handleIdentifier(child, formalParameterDeclaration)
                       listener: handleFormalParameterWithoutValue())
-                      listener: endFormalParameter(null, null, null, child, null, null, FormalParameterKind.mandatory, MemberKind.ExtensionStaticMethod)
+                      listener: endFormalParameter(null, null, null, child, null, null, FormalParameterKind.requiredPositional, MemberKind.ExtensionStaticMethod)
                     listener: endFormalParameters(1, (, ), MemberKind.ExtensionStaticMethod)
               parseInitializersOpt())
                 listener: handleNoInitializers()
diff --git a/pkg/front_end/parser_testcases/extensions/static_covariant.dart.expect b/pkg/front_end/parser_testcases/extensions/static_covariant.dart.expect
index 3224be6..45c1c22 100644
--- a/pkg/front_end/parser_testcases/extensions/static_covariant.dart.expect
+++ b/pkg/front_end/parser_testcases/extensions/static_covariant.dart.expect
@@ -64,7 +64,7 @@
                 handleType(A, null)
                 handleIdentifier(child, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, child, null, null, FormalParameterKind.mandatory, MemberKind.ExtensionStaticMethod)
+              endFormalParameter(null, null, null, child, null, null, FormalParameterKind.requiredPositional, MemberKind.ExtensionStaticMethod)
             endFormalParameters(1, (, ), MemberKind.ExtensionStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/extensions/static_covariant.dart.intertwined.expect b/pkg/front_end/parser_testcases/extensions/static_covariant.dart.intertwined.expect
index f23594f..25db406 100644
--- a/pkg/front_end/parser_testcases/extensions/static_covariant.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/extensions/static_covariant.dart.intertwined.expect
@@ -93,7 +93,7 @@
                 parseFormalParameters(addChild, MemberKind.ExtensionStaticMethod)
                   parseFormalParametersRest((, MemberKind.ExtensionStaticMethod)
                     listener: beginFormalParameters((, MemberKind.ExtensionStaticMethod)
-                    parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.ExtensionStaticMethod)
+                    parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.ExtensionStaticMethod)
                       parseMetadataStar(()
                         listener: beginMetadataStar(covariant)
                         listener: endMetadataStar(0)
@@ -106,7 +106,7 @@
                       ensureIdentifier(A, formalParameterDeclaration)
                         listener: handleIdentifier(child, formalParameterDeclaration)
                       listener: handleFormalParameterWithoutValue())
-                      listener: endFormalParameter(null, null, null, child, null, null, FormalParameterKind.mandatory, MemberKind.ExtensionStaticMethod)
+                      listener: endFormalParameter(null, null, null, child, null, null, FormalParameterKind.requiredPositional, MemberKind.ExtensionStaticMethod)
                     listener: endFormalParameters(1, (, ), MemberKind.ExtensionStaticMethod)
               parseInitializersOpt())
                 listener: handleNoInitializers()
diff --git a/pkg/front_end/parser_testcases/general/built_in_identifier_class_methods.dart.expect b/pkg/front_end/parser_testcases/general/built_in_identifier_class_methods.dart.expect
index 65c4451..54576a8 100644
--- a/pkg/front_end/parser_testcases/general/built_in_identifier_class_methods.dart.expect
+++ b/pkg/front_end/parser_testcases/general/built_in_identifier_class_methods.dart.expect
@@ -29,7 +29,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -84,7 +84,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -139,7 +139,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -194,7 +194,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -249,7 +249,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -304,7 +304,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -359,7 +359,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -414,7 +414,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -469,7 +469,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -524,7 +524,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -579,7 +579,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -634,7 +634,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -689,7 +689,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -744,7 +744,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -799,7 +799,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -854,7 +854,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -909,7 +909,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -964,7 +964,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -1019,7 +1019,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -1074,7 +1074,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/general/built_in_identifier_class_methods.dart.intertwined.expect b/pkg/front_end/parser_testcases/general/built_in_identifier_class_methods.dart.intertwined.expect
index 8006263..d53e616 100644
--- a/pkg/front_end/parser_testcases/general/built_in_identifier_class_methods.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/general/built_in_identifier_class_methods.dart.intertwined.expect
@@ -45,7 +45,7 @@
                   parseFormalParameters(abstract, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -56,7 +56,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -182,7 +182,7 @@
                   parseFormalParameters(as, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -193,7 +193,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -319,7 +319,7 @@
                   parseFormalParameters(covariant, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -330,7 +330,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -456,7 +456,7 @@
                   parseFormalParameters(deferred, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -467,7 +467,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -593,7 +593,7 @@
                   parseFormalParameters(dynamic, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -604,7 +604,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -730,7 +730,7 @@
                   parseFormalParameters(export, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -741,7 +741,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -867,7 +867,7 @@
                   parseFormalParameters(external, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -878,7 +878,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -1004,7 +1004,7 @@
                   parseFormalParameters(factory, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1015,7 +1015,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -1141,7 +1141,7 @@
                   parseFormalParameters(Function, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1152,7 +1152,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -1279,7 +1279,7 @@
                   parseFormalParameters(get, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1290,7 +1290,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -1416,7 +1416,7 @@
                   parseFormalParameters(implements, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1427,7 +1427,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -1553,7 +1553,7 @@
                   parseFormalParameters(import, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1564,7 +1564,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -1690,7 +1690,7 @@
                   parseFormalParameters(interface, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1701,7 +1701,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -1827,7 +1827,7 @@
                   parseFormalParameters(library, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1838,7 +1838,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -1966,7 +1966,7 @@
                   parseFormalParameters(operator, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -1977,7 +1977,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -2103,7 +2103,7 @@
                   parseFormalParameters(mixin, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -2114,7 +2114,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -2240,7 +2240,7 @@
                   parseFormalParameters(part, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -2251,7 +2251,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -2378,7 +2378,7 @@
                   parseFormalParameters(set, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -2389,7 +2389,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -2515,7 +2515,7 @@
                   parseFormalParameters(static, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -2526,7 +2526,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -2652,7 +2652,7 @@
                   parseFormalParameters(typedef, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -2663,7 +2663,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
diff --git a/pkg/front_end/parser_testcases/general/built_in_identifier_top_level_methods.dart.expect b/pkg/front_end/parser_testcases/general/built_in_identifier_top_level_methods.dart.expect
index ed37033..09cc1ba 100644
--- a/pkg/front_end/parser_testcases/general/built_in_identifier_top_level_methods.dart.expect
+++ b/pkg/front_end/parser_testcases/general/built_in_identifier_top_level_methods.dart.expect
@@ -17,7 +17,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -71,7 +71,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -125,7 +125,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -179,7 +179,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -233,7 +233,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -287,7 +287,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -341,7 +341,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -395,7 +395,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -449,7 +449,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -503,7 +503,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -557,7 +557,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -611,7 +611,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -665,7 +665,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -719,7 +719,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -773,7 +773,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -827,7 +827,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -881,7 +881,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -935,7 +935,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -989,7 +989,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -1043,7 +1043,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/general/built_in_identifier_top_level_methods.dart.intertwined.expect b/pkg/front_end/parser_testcases/general/built_in_identifier_top_level_methods.dart.intertwined.expect
index 3657522..9bc5625 100644
--- a/pkg/front_end/parser_testcases/general/built_in_identifier_top_level_methods.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/general/built_in_identifier_top_level_methods.dart.intertwined.expect
@@ -21,7 +21,7 @@
           parseFormalParameters(abstract, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -32,7 +32,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -154,7 +154,7 @@
           parseFormalParameters(as, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -165,7 +165,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -287,7 +287,7 @@
           parseFormalParameters(covariant, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -298,7 +298,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -420,7 +420,7 @@
           parseFormalParameters(deferred, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -431,7 +431,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -553,7 +553,7 @@
           parseFormalParameters(dynamic, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -564,7 +564,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -686,7 +686,7 @@
           parseFormalParameters(export, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -697,7 +697,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -819,7 +819,7 @@
           parseFormalParameters(external, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -830,7 +830,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -952,7 +952,7 @@
           parseFormalParameters(factory, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -963,7 +963,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -1085,7 +1085,7 @@
           parseFormalParameters(Function, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -1096,7 +1096,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -1218,7 +1218,7 @@
           parseFormalParameters(get, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -1229,7 +1229,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -1351,7 +1351,7 @@
           parseFormalParameters(implements, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -1362,7 +1362,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -1484,7 +1484,7 @@
           parseFormalParameters(import, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -1495,7 +1495,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -1617,7 +1617,7 @@
           parseFormalParameters(interface, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -1628,7 +1628,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -1750,7 +1750,7 @@
           parseFormalParameters(library, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -1761,7 +1761,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -1883,7 +1883,7 @@
           parseFormalParameters(operator, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -1894,7 +1894,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -2016,7 +2016,7 @@
           parseFormalParameters(mixin, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -2027,7 +2027,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -2149,7 +2149,7 @@
           parseFormalParameters(part, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -2160,7 +2160,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -2282,7 +2282,7 @@
           parseFormalParameters(set, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -2293,7 +2293,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -2415,7 +2415,7 @@
           parseFormalParameters(static, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -2426,7 +2426,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -2548,7 +2548,7 @@
           parseFormalParameters(typedef, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -2559,7 +2559,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/general/call_on_after_try_block.dart.expect b/pkg/front_end/parser_testcases/general/call_on_after_try_block.dart.expect
index bbc6919..0ed8d05 100644
--- a/pkg/front_end/parser_testcases/general/call_on_after_try_block.dart.expect
+++ b/pkg/front_end/parser_testcases/general/call_on_after_try_block.dart.expect
@@ -22,7 +22,7 @@
                 handleNoType(()
                 handleIdentifier(e, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.Catch)
+              endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.Catch)
             endFormalParameters(1, (, ), MemberKind.Catch)
           endCatchClause({)
           beginBlock({, BlockKind(catch clause))
diff --git a/pkg/front_end/parser_testcases/general/call_on_after_try_block.dart.intertwined.expect b/pkg/front_end/parser_testcases/general/call_on_after_try_block.dart.intertwined.expect
index 5a8b511..5ec70ff 100644
--- a/pkg/front_end/parser_testcases/general/call_on_after_try_block.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/general/call_on_after_try_block.dart.intertwined.expect
@@ -44,7 +44,7 @@
                 parseFormalParameters(catch, MemberKind.Catch)
                   parseFormalParametersRest((, MemberKind.Catch)
                     listener: beginFormalParameters((, MemberKind.Catch)
-                    parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.Catch)
+                    parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.Catch)
                       parseMetadataStar(()
                         listener: beginMetadataStar(e)
                         listener: endMetadataStar(0)
@@ -53,7 +53,7 @@
                       ensureIdentifier((, formalParameterDeclaration)
                         listener: handleIdentifier(e, formalParameterDeclaration)
                       listener: handleFormalParameterWithoutValue())
-                      listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.Catch)
+                      listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.Catch)
                     listener: endFormalParameters(1, (, ), MemberKind.Catch)
                 listener: endCatchClause({)
                 parseBlock(), BlockKind(catch clause))
diff --git a/pkg/front_end/parser_testcases/general/call_on_after_try_block2.dart.expect b/pkg/front_end/parser_testcases/general/call_on_after_try_block2.dart.expect
index 2622377..76ae8fa 100644
--- a/pkg/front_end/parser_testcases/general/call_on_after_try_block2.dart.expect
+++ b/pkg/front_end/parser_testcases/general/call_on_after_try_block2.dart.expect
@@ -22,7 +22,7 @@
                 handleNoType(()
                 handleIdentifier(e, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.Catch)
+              endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.Catch)
             endFormalParameters(1, (, ), MemberKind.Catch)
           endCatchClause({)
           beginBlock({, BlockKind(catch clause))
@@ -54,7 +54,7 @@
               handleNoType(()
               handleIdentifier(e, formalParameterDeclaration)
               handleFormalParameterWithoutValue())
-            endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.Local)
+            endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.Local)
           endFormalParameters(1, (, ), MemberKind.Local)
           handleNoInitializers()
           handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/general/call_on_after_try_block2.dart.intertwined.expect b/pkg/front_end/parser_testcases/general/call_on_after_try_block2.dart.intertwined.expect
index 16b73ff..c07d0c6 100644
--- a/pkg/front_end/parser_testcases/general/call_on_after_try_block2.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/general/call_on_after_try_block2.dart.intertwined.expect
@@ -44,7 +44,7 @@
                 parseFormalParameters(catch, MemberKind.Catch)
                   parseFormalParametersRest((, MemberKind.Catch)
                     listener: beginFormalParameters((, MemberKind.Catch)
-                    parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.Catch)
+                    parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.Catch)
                       parseMetadataStar(()
                         listener: beginMetadataStar(e)
                         listener: endMetadataStar(0)
@@ -53,7 +53,7 @@
                       ensureIdentifier((, formalParameterDeclaration)
                         listener: handleIdentifier(e, formalParameterDeclaration)
                       listener: handleFormalParameterWithoutValue())
-                      listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.Catch)
+                      listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.Catch)
                     listener: endFormalParameters(1, (, ), MemberKind.Catch)
                 listener: endCatchClause({)
                 parseBlock(), BlockKind(catch clause))
@@ -104,7 +104,7 @@
                     parseFormalParametersRequiredOpt(on, MemberKind.Local)
                       parseFormalParametersRest((, MemberKind.Local)
                         listener: beginFormalParameters((, MemberKind.Local)
-                        parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.Local)
+                        parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.Local)
                           parseMetadataStar(()
                             listener: beginMetadataStar(e)
                             listener: endMetadataStar(0)
@@ -113,7 +113,7 @@
                           ensureIdentifier((, formalParameterDeclaration)
                             listener: handleIdentifier(e, formalParameterDeclaration)
                           listener: handleFormalParameterWithoutValue())
-                          listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.Local)
+                          listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.Local)
                         listener: endFormalParameters(1, (, ), MemberKind.Local)
                     parseInitializersOpt())
                       listener: handleNoInitializers()
diff --git a/pkg/front_end/parser_testcases/general/call_on_after_try_block2_prime.dart.expect b/pkg/front_end/parser_testcases/general/call_on_after_try_block2_prime.dart.expect
index 0bd07bd..2dfc599 100644
--- a/pkg/front_end/parser_testcases/general/call_on_after_try_block2_prime.dart.expect
+++ b/pkg/front_end/parser_testcases/general/call_on_after_try_block2_prime.dart.expect
@@ -22,7 +22,7 @@
                 handleNoType(()
                 handleIdentifier(e, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.Catch)
+              endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.Catch)
             endFormalParameters(1, (, ), MemberKind.Catch)
           endCatchClause({)
           beginBlock({, BlockKind(catch clause))
@@ -54,7 +54,7 @@
               handleNoType(()
               handleIdentifier(e, formalParameterDeclaration)
               handleFormalParameterWithoutValue())
-            endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.Local)
+            endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.Local)
           endFormalParameters(1, (, ), MemberKind.Local)
           handleNoInitializers()
           handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/general/call_on_after_try_block2_prime.dart.intertwined.expect b/pkg/front_end/parser_testcases/general/call_on_after_try_block2_prime.dart.intertwined.expect
index 6922931..f97eb71 100644
--- a/pkg/front_end/parser_testcases/general/call_on_after_try_block2_prime.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/general/call_on_after_try_block2_prime.dart.intertwined.expect
@@ -44,7 +44,7 @@
                 parseFormalParameters(catch, MemberKind.Catch)
                   parseFormalParametersRest((, MemberKind.Catch)
                     listener: beginFormalParameters((, MemberKind.Catch)
-                    parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.Catch)
+                    parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.Catch)
                       parseMetadataStar(()
                         listener: beginMetadataStar(e)
                         listener: endMetadataStar(0)
@@ -53,7 +53,7 @@
                       ensureIdentifier((, formalParameterDeclaration)
                         listener: handleIdentifier(e, formalParameterDeclaration)
                       listener: handleFormalParameterWithoutValue())
-                      listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.Catch)
+                      listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.Catch)
                     listener: endFormalParameters(1, (, ), MemberKind.Catch)
                 listener: endCatchClause({)
                 parseBlock(), BlockKind(catch clause))
@@ -102,7 +102,7 @@
                   parseFormalParametersRequiredOpt(onX, MemberKind.Local)
                     parseFormalParametersRest((, MemberKind.Local)
                       listener: beginFormalParameters((, MemberKind.Local)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.Local)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.Local)
                         parseMetadataStar(()
                           listener: beginMetadataStar(e)
                           listener: endMetadataStar(0)
@@ -111,7 +111,7 @@
                         ensureIdentifier((, formalParameterDeclaration)
                           listener: handleIdentifier(e, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.Local)
+                        listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.Local)
                       listener: endFormalParameters(1, (, ), MemberKind.Local)
                   parseInitializersOpt())
                     listener: handleNoInitializers()
diff --git a/pkg/front_end/parser_testcases/general/call_on_after_try_block3.dart.expect b/pkg/front_end/parser_testcases/general/call_on_after_try_block3.dart.expect
index a76f004..fe1931e 100644
--- a/pkg/front_end/parser_testcases/general/call_on_after_try_block3.dart.expect
+++ b/pkg/front_end/parser_testcases/general/call_on_after_try_block3.dart.expect
@@ -15,7 +15,7 @@
           handleType(int, null)
           handleIdentifier(on, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, on, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, on, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -31,7 +31,7 @@
                 handleNoType(()
                 handleIdentifier(e, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.Catch)
+              endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.Catch)
             endFormalParameters(1, (, ), MemberKind.Catch)
           endCatchClause({)
           beginBlock({, BlockKind(catch clause))
diff --git a/pkg/front_end/parser_testcases/general/call_on_after_try_block3.dart.intertwined.expect b/pkg/front_end/parser_testcases/general/call_on_after_try_block3.dart.intertwined.expect
index 1961dd6..d336933 100644
--- a/pkg/front_end/parser_testcases/general/call_on_after_try_block3.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/general/call_on_after_try_block3.dart.intertwined.expect
@@ -19,7 +19,7 @@
           parseFormalParameters(main, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -31,7 +31,7 @@
                   inPlainSync()
                   listener: handleIdentifier(on, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, on, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, on, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -57,7 +57,7 @@
                 parseFormalParameters(catch, MemberKind.Catch)
                   parseFormalParametersRest((, MemberKind.Catch)
                     listener: beginFormalParameters((, MemberKind.Catch)
-                    parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.Catch)
+                    parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.Catch)
                       parseMetadataStar(()
                         listener: beginMetadataStar(e)
                         listener: endMetadataStar(0)
@@ -66,7 +66,7 @@
                       ensureIdentifier((, formalParameterDeclaration)
                         listener: handleIdentifier(e, formalParameterDeclaration)
                       listener: handleFormalParameterWithoutValue())
-                      listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.Catch)
+                      listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.Catch)
                     listener: endFormalParameters(1, (, ), MemberKind.Catch)
                 listener: endCatchClause({)
                 parseBlock(), BlockKind(catch clause))
diff --git a/pkg/front_end/parser_testcases/general/call_on_after_try_block3_prime.dart.expect b/pkg/front_end/parser_testcases/general/call_on_after_try_block3_prime.dart.expect
index 7ae894f..7a4f1c7 100644
--- a/pkg/front_end/parser_testcases/general/call_on_after_try_block3_prime.dart.expect
+++ b/pkg/front_end/parser_testcases/general/call_on_after_try_block3_prime.dart.expect
@@ -15,7 +15,7 @@
           handleType(int, null)
           handleIdentifier(onX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, onX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, onX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -31,7 +31,7 @@
                 handleNoType(()
                 handleIdentifier(e, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.Catch)
+              endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.Catch)
             endFormalParameters(1, (, ), MemberKind.Catch)
           endCatchClause({)
           beginBlock({, BlockKind(catch clause))
diff --git a/pkg/front_end/parser_testcases/general/call_on_after_try_block3_prime.dart.intertwined.expect b/pkg/front_end/parser_testcases/general/call_on_after_try_block3_prime.dart.intertwined.expect
index 10c263e..610ebd6 100644
--- a/pkg/front_end/parser_testcases/general/call_on_after_try_block3_prime.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/general/call_on_after_try_block3_prime.dart.intertwined.expect
@@ -19,7 +19,7 @@
           parseFormalParameters(main, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -30,7 +30,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(onX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, onX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, onX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -56,7 +56,7 @@
                 parseFormalParameters(catch, MemberKind.Catch)
                   parseFormalParametersRest((, MemberKind.Catch)
                     listener: beginFormalParameters((, MemberKind.Catch)
-                    parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.Catch)
+                    parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.Catch)
                       parseMetadataStar(()
                         listener: beginMetadataStar(e)
                         listener: endMetadataStar(0)
@@ -65,7 +65,7 @@
                       ensureIdentifier((, formalParameterDeclaration)
                         listener: handleIdentifier(e, formalParameterDeclaration)
                       listener: handleFormalParameterWithoutValue())
-                      listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.Catch)
+                      listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.Catch)
                     listener: endFormalParameters(1, (, ), MemberKind.Catch)
                 listener: endCatchClause({)
                 parseBlock(), BlockKind(catch clause))
diff --git a/pkg/front_end/parser_testcases/general/call_on_after_try_block4.dart.expect b/pkg/front_end/parser_testcases/general/call_on_after_try_block4.dart.expect
index 44a3071..74d2acb 100644
--- a/pkg/front_end/parser_testcases/general/call_on_after_try_block4.dart.expect
+++ b/pkg/front_end/parser_testcases/general/call_on_after_try_block4.dart.expect
@@ -15,7 +15,7 @@
           handleType(int, null)
           handleIdentifier(on, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, on, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, on, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -31,7 +31,7 @@
                 handleNoType(()
                 handleIdentifier(e, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.Catch)
+              endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.Catch)
             endFormalParameters(1, (, ), MemberKind.Catch)
           endCatchClause({)
           beginBlock({, BlockKind(catch clause))
diff --git a/pkg/front_end/parser_testcases/general/call_on_after_try_block4.dart.intertwined.expect b/pkg/front_end/parser_testcases/general/call_on_after_try_block4.dart.intertwined.expect
index 3fee6f6..e47aced 100644
--- a/pkg/front_end/parser_testcases/general/call_on_after_try_block4.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/general/call_on_after_try_block4.dart.intertwined.expect
@@ -19,7 +19,7 @@
           parseFormalParameters(main, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -31,7 +31,7 @@
                   inPlainSync()
                   listener: handleIdentifier(on, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, on, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, on, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -57,7 +57,7 @@
                 parseFormalParameters(catch, MemberKind.Catch)
                   parseFormalParametersRest((, MemberKind.Catch)
                     listener: beginFormalParameters((, MemberKind.Catch)
-                    parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.Catch)
+                    parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.Catch)
                       parseMetadataStar(()
                         listener: beginMetadataStar(e)
                         listener: endMetadataStar(0)
@@ -66,7 +66,7 @@
                       ensureIdentifier((, formalParameterDeclaration)
                         listener: handleIdentifier(e, formalParameterDeclaration)
                       listener: handleFormalParameterWithoutValue())
-                      listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.Catch)
+                      listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.Catch)
                     listener: endFormalParameters(1, (, ), MemberKind.Catch)
                 listener: endCatchClause({)
                 parseBlock(), BlockKind(catch clause))
diff --git a/pkg/front_end/parser_testcases/general/call_on_after_try_block4_prime.dart.expect b/pkg/front_end/parser_testcases/general/call_on_after_try_block4_prime.dart.expect
index dff16a5..b1a6d3b 100644
--- a/pkg/front_end/parser_testcases/general/call_on_after_try_block4_prime.dart.expect
+++ b/pkg/front_end/parser_testcases/general/call_on_after_try_block4_prime.dart.expect
@@ -15,7 +15,7 @@
           handleType(int, null)
           handleIdentifier(onX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, onX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, onX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -31,7 +31,7 @@
                 handleNoType(()
                 handleIdentifier(e, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.Catch)
+              endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.Catch)
             endFormalParameters(1, (, ), MemberKind.Catch)
           endCatchClause({)
           beginBlock({, BlockKind(catch clause))
diff --git a/pkg/front_end/parser_testcases/general/call_on_after_try_block4_prime.dart.intertwined.expect b/pkg/front_end/parser_testcases/general/call_on_after_try_block4_prime.dart.intertwined.expect
index 4a8d11a..f7336c4 100644
--- a/pkg/front_end/parser_testcases/general/call_on_after_try_block4_prime.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/general/call_on_after_try_block4_prime.dart.intertwined.expect
@@ -19,7 +19,7 @@
           parseFormalParameters(main, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -30,7 +30,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(onX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, onX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, onX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -56,7 +56,7 @@
                 parseFormalParameters(catch, MemberKind.Catch)
                   parseFormalParametersRest((, MemberKind.Catch)
                     listener: beginFormalParameters((, MemberKind.Catch)
-                    parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.Catch)
+                    parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.Catch)
                       parseMetadataStar(()
                         listener: beginMetadataStar(e)
                         listener: endMetadataStar(0)
@@ -65,7 +65,7 @@
                       ensureIdentifier((, formalParameterDeclaration)
                         listener: handleIdentifier(e, formalParameterDeclaration)
                       listener: handleFormalParameterWithoutValue())
-                      listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.Catch)
+                      listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.Catch)
                     listener: endFormalParameters(1, (, ), MemberKind.Catch)
                 listener: endCatchClause({)
                 parseBlock(), BlockKind(catch clause))
diff --git a/pkg/front_end/parser_testcases/general/call_on_after_try_block5.dart.expect b/pkg/front_end/parser_testcases/general/call_on_after_try_block5.dart.expect
index 1318bfe..c65fbdb 100644
--- a/pkg/front_end/parser_testcases/general/call_on_after_try_block5.dart.expect
+++ b/pkg/front_end/parser_testcases/general/call_on_after_try_block5.dart.expect
@@ -15,7 +15,7 @@
           handleType(int, null)
           handleIdentifier(on, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, on, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, on, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -31,7 +31,7 @@
                 handleNoType(()
                 handleIdentifier(e, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.Catch)
+              endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.Catch)
             endFormalParameters(1, (, ), MemberKind.Catch)
           endCatchClause({)
           beginBlock({, BlockKind(catch clause))
diff --git a/pkg/front_end/parser_testcases/general/call_on_after_try_block5.dart.intertwined.expect b/pkg/front_end/parser_testcases/general/call_on_after_try_block5.dart.intertwined.expect
index 761800b..1c3467c 100644
--- a/pkg/front_end/parser_testcases/general/call_on_after_try_block5.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/general/call_on_after_try_block5.dart.intertwined.expect
@@ -19,7 +19,7 @@
           parseFormalParameters(main, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -31,7 +31,7 @@
                   inPlainSync()
                   listener: handleIdentifier(on, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, on, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, on, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -57,7 +57,7 @@
                 parseFormalParameters(catch, MemberKind.Catch)
                   parseFormalParametersRest((, MemberKind.Catch)
                     listener: beginFormalParameters((, MemberKind.Catch)
-                    parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.Catch)
+                    parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.Catch)
                       parseMetadataStar(()
                         listener: beginMetadataStar(e)
                         listener: endMetadataStar(0)
@@ -66,7 +66,7 @@
                       ensureIdentifier((, formalParameterDeclaration)
                         listener: handleIdentifier(e, formalParameterDeclaration)
                       listener: handleFormalParameterWithoutValue())
-                      listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.Catch)
+                      listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.Catch)
                     listener: endFormalParameters(1, (, ), MemberKind.Catch)
                 listener: endCatchClause({)
                 parseBlock(), BlockKind(catch clause))
diff --git a/pkg/front_end/parser_testcases/general/call_on_after_try_block5_prime.dart.expect b/pkg/front_end/parser_testcases/general/call_on_after_try_block5_prime.dart.expect
index f03df25..9b4da14 100644
--- a/pkg/front_end/parser_testcases/general/call_on_after_try_block5_prime.dart.expect
+++ b/pkg/front_end/parser_testcases/general/call_on_after_try_block5_prime.dart.expect
@@ -15,7 +15,7 @@
           handleType(int, null)
           handleIdentifier(onX, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, onX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, onX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -31,7 +31,7 @@
                 handleNoType(()
                 handleIdentifier(e, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.Catch)
+              endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.Catch)
             endFormalParameters(1, (, ), MemberKind.Catch)
           endCatchClause({)
           beginBlock({, BlockKind(catch clause))
diff --git a/pkg/front_end/parser_testcases/general/call_on_after_try_block5_prime.dart.intertwined.expect b/pkg/front_end/parser_testcases/general/call_on_after_try_block5_prime.dart.intertwined.expect
index 0570855..de467a3 100644
--- a/pkg/front_end/parser_testcases/general/call_on_after_try_block5_prime.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/general/call_on_after_try_block5_prime.dart.intertwined.expect
@@ -19,7 +19,7 @@
           parseFormalParameters(main, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -30,7 +30,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(onX, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, onX, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, onX, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -56,7 +56,7 @@
                 parseFormalParameters(catch, MemberKind.Catch)
                   parseFormalParametersRest((, MemberKind.Catch)
                     listener: beginFormalParameters((, MemberKind.Catch)
-                    parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.Catch)
+                    parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.Catch)
                       parseMetadataStar(()
                         listener: beginMetadataStar(e)
                         listener: endMetadataStar(0)
@@ -65,7 +65,7 @@
                       ensureIdentifier((, formalParameterDeclaration)
                         listener: handleIdentifier(e, formalParameterDeclaration)
                       listener: handleFormalParameterWithoutValue())
-                      listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.Catch)
+                      listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.Catch)
                     listener: endFormalParameters(1, (, ), MemberKind.Catch)
                 listener: endCatchClause({)
                 parseBlock(), BlockKind(catch clause))
diff --git a/pkg/front_end/parser_testcases/general/call_on_after_try_block_prime.dart.expect b/pkg/front_end/parser_testcases/general/call_on_after_try_block_prime.dart.expect
index 3848d33..8ebdaa9 100644
--- a/pkg/front_end/parser_testcases/general/call_on_after_try_block_prime.dart.expect
+++ b/pkg/front_end/parser_testcases/general/call_on_after_try_block_prime.dart.expect
@@ -22,7 +22,7 @@
                 handleNoType(()
                 handleIdentifier(e, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.Catch)
+              endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.Catch)
             endFormalParameters(1, (, ), MemberKind.Catch)
           endCatchClause({)
           beginBlock({, BlockKind(catch clause))
diff --git a/pkg/front_end/parser_testcases/general/call_on_after_try_block_prime.dart.intertwined.expect b/pkg/front_end/parser_testcases/general/call_on_after_try_block_prime.dart.intertwined.expect
index 40100a5..007fb4b 100644
--- a/pkg/front_end/parser_testcases/general/call_on_after_try_block_prime.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/general/call_on_after_try_block_prime.dart.intertwined.expect
@@ -44,7 +44,7 @@
                 parseFormalParameters(catch, MemberKind.Catch)
                   parseFormalParametersRest((, MemberKind.Catch)
                     listener: beginFormalParameters((, MemberKind.Catch)
-                    parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.Catch)
+                    parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.Catch)
                       parseMetadataStar(()
                         listener: beginMetadataStar(e)
                         listener: endMetadataStar(0)
@@ -53,7 +53,7 @@
                       ensureIdentifier((, formalParameterDeclaration)
                         listener: handleIdentifier(e, formalParameterDeclaration)
                       listener: handleFormalParameterWithoutValue())
-                      listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.Catch)
+                      listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.Catch)
                     listener: endFormalParameters(1, (, ), MemberKind.Catch)
                 listener: endCatchClause({)
                 parseBlock(), BlockKind(catch clause))
diff --git a/pkg/front_end/parser_testcases/general/chained_call_01.dart.expect b/pkg/front_end/parser_testcases/general/chained_call_01.dart.expect
index 514a391..af6819d 100644
--- a/pkg/front_end/parser_testcases/general/chained_call_01.dart.expect
+++ b/pkg/front_end/parser_testcases/general/chained_call_01.dart.expect
@@ -15,7 +15,7 @@
           handleType(dynamic, null)
           handleIdentifier(e, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/general/chained_call_01.dart.intertwined.expect b/pkg/front_end/parser_testcases/general/chained_call_01.dart.intertwined.expect
index 1d66387..fce21ba 100644
--- a/pkg/front_end/parser_testcases/general/chained_call_01.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/general/chained_call_01.dart.intertwined.expect
@@ -19,7 +19,7 @@
           parseFormalParameters(f, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(dynamic)
                   listener: endMetadataStar(0)
@@ -30,7 +30,7 @@
                 ensureIdentifier(dynamic, formalParameterDeclaration)
                   listener: handleIdentifier(e, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/general/chained_call_02.dart.expect b/pkg/front_end/parser_testcases/general/chained_call_02.dart.expect
index ab3cd87..d45db40 100644
--- a/pkg/front_end/parser_testcases/general/chained_call_02.dart.expect
+++ b/pkg/front_end/parser_testcases/general/chained_call_02.dart.expect
@@ -15,7 +15,7 @@
           handleType(dynamic, null)
           handleIdentifier(e, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/general/chained_call_02.dart.intertwined.expect b/pkg/front_end/parser_testcases/general/chained_call_02.dart.intertwined.expect
index 036a456..9579bc0 100644
--- a/pkg/front_end/parser_testcases/general/chained_call_02.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/general/chained_call_02.dart.intertwined.expect
@@ -19,7 +19,7 @@
           parseFormalParameters(f, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(dynamic)
                   listener: endMetadataStar(0)
@@ -30,7 +30,7 @@
                 ensureIdentifier(dynamic, formalParameterDeclaration)
                   listener: handleIdentifier(e, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/general/chained_call_03.dart.expect b/pkg/front_end/parser_testcases/general/chained_call_03.dart.expect
index a127cb2..100e880 100644
--- a/pkg/front_end/parser_testcases/general/chained_call_03.dart.expect
+++ b/pkg/front_end/parser_testcases/general/chained_call_03.dart.expect
@@ -15,7 +15,7 @@
           handleType(dynamic, null)
           handleIdentifier(e, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/general/chained_call_03.dart.intertwined.expect b/pkg/front_end/parser_testcases/general/chained_call_03.dart.intertwined.expect
index 5e86f7b..4807443 100644
--- a/pkg/front_end/parser_testcases/general/chained_call_03.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/general/chained_call_03.dart.intertwined.expect
@@ -19,7 +19,7 @@
           parseFormalParameters(f, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(dynamic)
                   listener: endMetadataStar(0)
@@ -30,7 +30,7 @@
                 ensureIdentifier(dynamic, formalParameterDeclaration)
                   listener: handleIdentifier(e, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/general/chained_call_04.dart.expect b/pkg/front_end/parser_testcases/general/chained_call_04.dart.expect
index 647163d..393d61d 100644
--- a/pkg/front_end/parser_testcases/general/chained_call_04.dart.expect
+++ b/pkg/front_end/parser_testcases/general/chained_call_04.dart.expect
@@ -15,7 +15,7 @@
           handleType(dynamic, null)
           handleIdentifier(e, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/general/chained_call_04.dart.intertwined.expect b/pkg/front_end/parser_testcases/general/chained_call_04.dart.intertwined.expect
index 47b2f02..cf46e41 100644
--- a/pkg/front_end/parser_testcases/general/chained_call_04.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/general/chained_call_04.dart.intertwined.expect
@@ -19,7 +19,7 @@
           parseFormalParameters(f, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(dynamic)
                   listener: endMetadataStar(0)
@@ -30,7 +30,7 @@
                 ensureIdentifier(dynamic, formalParameterDeclaration)
                   listener: handleIdentifier(e, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/general/chained_call_05.dart.expect b/pkg/front_end/parser_testcases/general/chained_call_05.dart.expect
index fc05dac..8b0e034 100644
--- a/pkg/front_end/parser_testcases/general/chained_call_05.dart.expect
+++ b/pkg/front_end/parser_testcases/general/chained_call_05.dart.expect
@@ -15,7 +15,7 @@
           handleType(dynamic, null)
           handleIdentifier(e, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/general/chained_call_05.dart.intertwined.expect b/pkg/front_end/parser_testcases/general/chained_call_05.dart.intertwined.expect
index dfe42d1..5434b21 100644
--- a/pkg/front_end/parser_testcases/general/chained_call_05.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/general/chained_call_05.dart.intertwined.expect
@@ -19,7 +19,7 @@
           parseFormalParameters(f, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(dynamic)
                   listener: endMetadataStar(0)
@@ -30,7 +30,7 @@
                 ensureIdentifier(dynamic, formalParameterDeclaration)
                   listener: handleIdentifier(e, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/general/chained_call_06.dart.expect b/pkg/front_end/parser_testcases/general/chained_call_06.dart.expect
index 76a1c9d..a754bf0 100644
--- a/pkg/front_end/parser_testcases/general/chained_call_06.dart.expect
+++ b/pkg/front_end/parser_testcases/general/chained_call_06.dart.expect
@@ -15,7 +15,7 @@
           handleType(dynamic, null)
           handleIdentifier(e, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/general/chained_call_06.dart.intertwined.expect b/pkg/front_end/parser_testcases/general/chained_call_06.dart.intertwined.expect
index 19f3f2c..f308d99 100644
--- a/pkg/front_end/parser_testcases/general/chained_call_06.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/general/chained_call_06.dart.intertwined.expect
@@ -19,7 +19,7 @@
           parseFormalParameters(f, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(dynamic)
                   listener: endMetadataStar(0)
@@ -30,7 +30,7 @@
                 ensureIdentifier(dynamic, formalParameterDeclaration)
                   listener: handleIdentifier(e, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/general/chained_call_07.dart.expect b/pkg/front_end/parser_testcases/general/chained_call_07.dart.expect
index d7bc5fb..fc5d52b 100644
--- a/pkg/front_end/parser_testcases/general/chained_call_07.dart.expect
+++ b/pkg/front_end/parser_testcases/general/chained_call_07.dart.expect
@@ -15,7 +15,7 @@
           handleType(dynamic, null)
           handleIdentifier(e, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/general/chained_call_07.dart.intertwined.expect b/pkg/front_end/parser_testcases/general/chained_call_07.dart.intertwined.expect
index dbf54d7..9129a71 100644
--- a/pkg/front_end/parser_testcases/general/chained_call_07.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/general/chained_call_07.dart.intertwined.expect
@@ -19,7 +19,7 @@
           parseFormalParameters(f, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(dynamic)
                   listener: endMetadataStar(0)
@@ -30,7 +30,7 @@
                 ensureIdentifier(dynamic, formalParameterDeclaration)
                   listener: handleIdentifier(e, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/general/generic_function_typedef.dart.expect b/pkg/front_end/parser_testcases/general/generic_function_typedef.dart.expect
index dca4bd9..6ad4a38 100644
--- a/pkg/front_end/parser_testcases/general/generic_function_typedef.dart.expect
+++ b/pkg/front_end/parser_testcases/general/generic_function_typedef.dart.expect
@@ -614,7 +614,7 @@
             endFunctionType(Function, null)
             handleNoName())
             handleFormalParameterWithoutValue())
-          endFormalParameter(null, null, null, ), null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+          endFormalParameter(null, null, null, ), null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
         endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
       endFunctionType(Function, null)
     endTypedef(typedef, =, ;)
@@ -650,7 +650,7 @@
             endFunctionType(Function, null)
             handleNoName())
             handleFormalParameterWithoutValue())
-          endFormalParameter(null, null, null, ), null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+          endFormalParameter(null, null, null, ), null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
         endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
       endFunctionType(Function, null)
     endTypedef(typedef, =, ;)
@@ -690,7 +690,7 @@
             endFunctionType(Function, null)
             handleNoName())
             handleFormalParameterWithoutValue())
-          endFormalParameter(null, null, null, ), null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+          endFormalParameter(null, null, null, ), null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
         endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
       endFunctionType(Function, null)
     endTypedef(typedef, =, ;)
@@ -734,7 +734,7 @@
             endFunctionType(Function, null)
             handleNoName())
             handleFormalParameterWithoutValue())
-          endFormalParameter(null, null, null, ), null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+          endFormalParameter(null, null, null, ), null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
         endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
       endFunctionType(Function, null)
     endTypedef(typedef, =, ;)
@@ -778,7 +778,7 @@
             endFunctionType(Function, null)
             handleNoName())
             handleFormalParameterWithoutValue())
-          endFormalParameter(null, null, null, ), null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+          endFormalParameter(null, null, null, ), null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
         endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
       endFunctionType(Function, null)
     endTypedef(typedef, =, ;)
@@ -822,7 +822,7 @@
             endFunctionType(Function, null)
             handleNoName())
             handleFormalParameterWithoutValue())
-          endFormalParameter(null, null, null, ), null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+          endFormalParameter(null, null, null, ), null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
         endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
       endFunctionType(Function, null)
     endTypedef(typedef, =, ;)
diff --git a/pkg/front_end/parser_testcases/general/generic_function_typedef.dart.intertwined.expect b/pkg/front_end/parser_testcases/general/generic_function_typedef.dart.intertwined.expect
index f2c7a7f..227449a 100644
--- a/pkg/front_end/parser_testcases/general/generic_function_typedef.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/general/generic_function_typedef.dart.intertwined.expect
@@ -819,7 +819,7 @@
         parseFormalParametersRequiredOpt(Function, MemberKind.GeneralizedFunctionType)
           parseFormalParametersRest((, MemberKind.GeneralizedFunctionType)
             listener: beginFormalParameters((, MemberKind.GeneralizedFunctionType)
-            parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+            parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
               parseMetadataStar(()
                 listener: beginMetadataStar(void)
                 listener: endMetadataStar(0)
@@ -842,7 +842,7 @@
               listener: endFunctionType(Function, null)
               listener: handleNoName())
               listener: handleFormalParameterWithoutValue())
-              listener: endFormalParameter(null, null, null, ), null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+              listener: endFormalParameter(null, null, null, ), null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
             listener: endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
         listener: endFunctionType(Function, null)
         ensureSemicolon())
@@ -865,7 +865,7 @@
         parseFormalParametersRequiredOpt(Function, MemberKind.GeneralizedFunctionType)
           parseFormalParametersRest((, MemberKind.GeneralizedFunctionType)
             listener: beginFormalParameters((, MemberKind.GeneralizedFunctionType)
-            parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+            parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
               parseMetadataStar(()
                 listener: beginMetadataStar(void)
                 listener: endMetadataStar(0)
@@ -892,7 +892,7 @@
               listener: endFunctionType(Function, null)
               listener: handleNoName())
               listener: handleFormalParameterWithoutValue())
-              listener: endFormalParameter(null, null, null, ), null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+              listener: endFormalParameter(null, null, null, ), null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
             listener: endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
         listener: endFunctionType(Function, null)
         ensureSemicolon())
@@ -915,7 +915,7 @@
         parseFormalParametersRequiredOpt(Function, MemberKind.GeneralizedFunctionType)
           parseFormalParametersRest((, MemberKind.GeneralizedFunctionType)
             listener: beginFormalParameters((, MemberKind.GeneralizedFunctionType)
-            parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+            parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
               parseMetadataStar(()
                 listener: beginMetadataStar(void)
                 listener: endMetadataStar(0)
@@ -948,7 +948,7 @@
               listener: endFunctionType(Function, null)
               listener: handleNoName())
               listener: handleFormalParameterWithoutValue())
-              listener: endFormalParameter(null, null, null, ), null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+              listener: endFormalParameter(null, null, null, ), null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
             listener: endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
         listener: endFunctionType(Function, null)
         ensureSemicolon())
@@ -971,7 +971,7 @@
         parseFormalParametersRequiredOpt(Function, MemberKind.GeneralizedFunctionType)
           parseFormalParametersRest((, MemberKind.GeneralizedFunctionType)
             listener: beginFormalParameters((, MemberKind.GeneralizedFunctionType)
-            parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+            parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
               parseMetadataStar(()
                 listener: beginMetadataStar(void)
                 listener: endMetadataStar(0)
@@ -1008,7 +1008,7 @@
               listener: endFunctionType(Function, null)
               listener: handleNoName())
               listener: handleFormalParameterWithoutValue())
-              listener: endFormalParameter(null, null, null, ), null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+              listener: endFormalParameter(null, null, null, ), null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
             listener: endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
         listener: endFunctionType(Function, null)
         ensureSemicolon())
@@ -1031,7 +1031,7 @@
         parseFormalParametersRequiredOpt(Function, MemberKind.GeneralizedFunctionType)
           parseFormalParametersRest((, MemberKind.GeneralizedFunctionType)
             listener: beginFormalParameters((, MemberKind.GeneralizedFunctionType)
-            parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+            parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
               parseMetadataStar(()
                 listener: beginMetadataStar(void)
                 listener: endMetadataStar(0)
@@ -1068,7 +1068,7 @@
               listener: endFunctionType(Function, null)
               listener: handleNoName())
               listener: handleFormalParameterWithoutValue())
-              listener: endFormalParameter(null, null, null, ), null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+              listener: endFormalParameter(null, null, null, ), null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
             listener: endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
         listener: endFunctionType(Function, null)
         ensureSemicolon())
@@ -1091,7 +1091,7 @@
         parseFormalParametersRequiredOpt(Function, MemberKind.GeneralizedFunctionType)
           parseFormalParametersRest((, MemberKind.GeneralizedFunctionType)
             listener: beginFormalParameters((, MemberKind.GeneralizedFunctionType)
-            parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+            parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
               parseMetadataStar(()
                 listener: beginMetadataStar(void)
                 listener: endMetadataStar(0)
@@ -1128,7 +1128,7 @@
               listener: endFunctionType(Function, null)
               listener: handleNoName())
               listener: handleFormalParameterWithoutValue())
-              listener: endFormalParameter(null, null, null, ), null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+              listener: endFormalParameter(null, null, null, ), null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
             listener: endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
         listener: endFunctionType(Function, null)
         ensureSemicolon())
diff --git a/pkg/front_end/parser_testcases/general/issue_41121.dart.expect b/pkg/front_end/parser_testcases/general/issue_41121.dart.expect
index 4962c43..890482b 100644
--- a/pkg/front_end/parser_testcases/general/issue_41121.dart.expect
+++ b/pkg/front_end/parser_testcases/general/issue_41121.dart.expect
@@ -80,7 +80,7 @@
                 handleType(Configuration, null)
                 handleIdentifier(configuration, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, configuration, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, configuration, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             beginInitializers(:)
               beginInitializer(assert)
@@ -127,7 +127,7 @@
                 handleType(Configuration, null)
                 handleIdentifier(configuration, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, configuration, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, configuration, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             beginInitializers(:)
               beginInitializer(assert)
diff --git a/pkg/front_end/parser_testcases/general/issue_41121.dart.intertwined.expect b/pkg/front_end/parser_testcases/general/issue_41121.dart.intertwined.expect
index 7b2445b..d36c146 100644
--- a/pkg/front_end/parser_testcases/general/issue_41121.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/general/issue_41121.dart.intertwined.expect
@@ -61,7 +61,7 @@
                   parseFormalParameters(ConfigurationService, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(Configuration)
                           listener: endMetadataStar(0)
@@ -72,7 +72,7 @@
                         ensureIdentifier(Configuration, formalParameterDeclaration)
                           listener: handleIdentifier(configuration, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, configuration, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, configuration, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   parseInitializers(:)
@@ -161,7 +161,7 @@
                   parseFormalParameters(configuration, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(Configuration)
                           listener: endMetadataStar(0)
@@ -172,7 +172,7 @@
                         ensureIdentifier(Configuration, formalParameterDeclaration)
                           listener: handleIdentifier(configuration, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, configuration, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, configuration, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   parseInitializers(:)
diff --git a/pkg/front_end/parser_testcases/general/issue_45120.dart.expect b/pkg/front_end/parser_testcases/general/issue_45120.dart.expect
index 911e2dd..4bcd475 100644
--- a/pkg/front_end/parser_testcases/general/issue_45120.dart.expect
+++ b/pkg/front_end/parser_testcases/general/issue_45120.dart.expect
@@ -79,7 +79,7 @@
             handleType(int, null)
             handleNoName())
             handleFormalParameterWithoutValue())
-          endFormalParameter(null, null, null, ), null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+          endFormalParameter(null, null, null, ), null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
         endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
       endFunctionType(Function, null)
     endTypedef(typedef, =, ;)
@@ -150,7 +150,7 @@
               handleType(int, null)
               handleIdentifier(y, formalParameterDeclaration)
               handleFormalParameterWithoutValue())
-            endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+            endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
           endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
         endFunctionType(Function, ?)
         beginVariablesDeclaration(f, null, null)
diff --git a/pkg/front_end/parser_testcases/general/issue_45120.dart.intertwined.expect b/pkg/front_end/parser_testcases/general/issue_45120.dart.intertwined.expect
index a2eaf9f..846f5fe 100644
--- a/pkg/front_end/parser_testcases/general/issue_45120.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/general/issue_45120.dart.intertwined.expect
@@ -108,7 +108,7 @@
         parseFormalParametersRequiredOpt(>, MemberKind.GeneralizedFunctionType)
           parseFormalParametersRest((, MemberKind.GeneralizedFunctionType)
             listener: beginFormalParameters((, MemberKind.GeneralizedFunctionType)
-            parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+            parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
               parseMetadataStar(()
                 listener: beginMetadataStar(@)
                 parseMetadata(()
@@ -140,7 +140,7 @@
               listener: handleType(int, null)
               listener: handleNoName())
               listener: handleFormalParameterWithoutValue())
-              listener: endFormalParameter(null, null, null, ), null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+              listener: endFormalParameter(null, null, null, ), null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
             listener: endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
         listener: endFunctionType(Function, null)
         ensureSemicolon())
@@ -238,7 +238,7 @@
                   parseFormalParametersRequiredOpt(>, MemberKind.GeneralizedFunctionType)
                     parseFormalParametersRest((, MemberKind.GeneralizedFunctionType)
                       listener: beginFormalParameters((, MemberKind.GeneralizedFunctionType)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
                         parseMetadataStar(()
                           listener: beginMetadataStar(@)
                           parseMetadata(()
@@ -271,7 +271,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(y, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+                        listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
                       listener: endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
                   listener: endFunctionType(Function, ?)
                   listener: beginVariablesDeclaration(f, null, null)
diff --git a/pkg/front_end/parser_testcases/general/issue_45848_01.dart.expect b/pkg/front_end/parser_testcases/general/issue_45848_01.dart.expect
index 213652b..63a4760 100644
--- a/pkg/front_end/parser_testcases/general/issue_45848_01.dart.expect
+++ b/pkg/front_end/parser_testcases/general/issue_45848_01.dart.expect
@@ -15,7 +15,7 @@
           handleType(bool, null)
           handleIdentifier(b, formalParameterDeclaration)
           handleFormalParameterWithoutValue(,)
-        endFormalParameter(null, null, null, b, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, b, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
         beginMetadataStar(int)
         endMetadataStar(0)
         beginFormalParameter(int, MemberKind.TopLevelMethod, null, null, null)
@@ -24,7 +24,7 @@
           handleType(int, null)
           handleIdentifier(i, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, i, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, i, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(2, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -67,7 +67,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue(,)
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
         beginMetadataStar(int)
         endMetadataStar(0)
         beginFormalParameter(int, MemberKind.TopLevelMethod, null, null, null)
@@ -76,7 +76,7 @@
           handleType(int, null)
           handleIdentifier(y, formalParameterDeclaration)
           handleFormalParameterWithoutValue(,)
-        endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
         beginMetadataStar(Object)
         endMetadataStar(0)
         beginFormalParameter(Object, MemberKind.TopLevelMethod, null, null, null)
@@ -85,7 +85,7 @@
           handleType(Object, null)
           handleIdentifier(o, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, o, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, o, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(3, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/general/issue_45848_01.dart.intertwined.expect b/pkg/front_end/parser_testcases/general/issue_45848_01.dart.intertwined.expect
index fb14934..762eb6c 100644
--- a/pkg/front_end/parser_testcases/general/issue_45848_01.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/general/issue_45848_01.dart.intertwined.expect
@@ -19,7 +19,7 @@
           parseFormalParameters(f, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(bool)
                   listener: endMetadataStar(0)
@@ -30,8 +30,8 @@
                 ensureIdentifier(bool, formalParameterDeclaration)
                   listener: handleIdentifier(b, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue(,)
-                listener: endFormalParameter(null, null, null, b, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
-              parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, b, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
+              parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(,)
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -42,7 +42,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(i, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, i, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, i, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(2, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -128,7 +128,7 @@
           parseFormalParameters(g, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -139,8 +139,8 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue(,)
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
-              parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
+              parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(,)
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -151,8 +151,8 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(y, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue(,)
-                listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
-              parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
+              parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(,)
                   listener: beginMetadataStar(Object)
                   listener: endMetadataStar(0)
@@ -163,7 +163,7 @@
                 ensureIdentifier(Object, formalParameterDeclaration)
                   listener: handleIdentifier(o, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, o, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, o, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(3, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/general/issue_45848_01_prime.dart.expect b/pkg/front_end/parser_testcases/general/issue_45848_01_prime.dart.expect
index 2f24240..20a4b28 100644
--- a/pkg/front_end/parser_testcases/general/issue_45848_01_prime.dart.expect
+++ b/pkg/front_end/parser_testcases/general/issue_45848_01_prime.dart.expect
@@ -15,7 +15,7 @@
           handleType(bool, null)
           handleIdentifier(b, formalParameterDeclaration)
           handleFormalParameterWithoutValue(,)
-        endFormalParameter(null, null, null, b, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, b, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
         beginMetadataStar(int)
         endMetadataStar(0)
         beginFormalParameter(int, MemberKind.TopLevelMethod, null, null, null)
@@ -24,7 +24,7 @@
           handleType(int, null)
           handleIdentifier(i, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, i, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, i, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(2, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -67,7 +67,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue(,)
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
         beginMetadataStar(int)
         endMetadataStar(0)
         beginFormalParameter(int, MemberKind.TopLevelMethod, null, null, null)
@@ -76,7 +76,7 @@
           handleType(int, null)
           handleIdentifier(y, formalParameterDeclaration)
           handleFormalParameterWithoutValue(,)
-        endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
         beginMetadataStar(Object)
         endMetadataStar(0)
         beginFormalParameter(Object, MemberKind.TopLevelMethod, null, null, null)
@@ -85,7 +85,7 @@
           handleType(Object, null)
           handleIdentifier(o, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, o, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, o, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(3, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/general/issue_45848_01_prime.dart.intertwined.expect b/pkg/front_end/parser_testcases/general/issue_45848_01_prime.dart.intertwined.expect
index c5323dd..6649435 100644
--- a/pkg/front_end/parser_testcases/general/issue_45848_01_prime.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/general/issue_45848_01_prime.dart.intertwined.expect
@@ -19,7 +19,7 @@
           parseFormalParameters(f, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(bool)
                   listener: endMetadataStar(0)
@@ -30,8 +30,8 @@
                 ensureIdentifier(bool, formalParameterDeclaration)
                   listener: handleIdentifier(b, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue(,)
-                listener: endFormalParameter(null, null, null, b, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
-              parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, b, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
+              parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(,)
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -42,7 +42,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(i, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, i, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, i, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(2, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -128,7 +128,7 @@
           parseFormalParameters(g, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -139,8 +139,8 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue(,)
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
-              parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
+              parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(,)
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -151,8 +151,8 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(y, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue(,)
-                listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
-              parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
+              parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(,)
                   listener: beginMetadataStar(Object)
                   listener: endMetadataStar(0)
@@ -163,7 +163,7 @@
                 ensureIdentifier(Object, formalParameterDeclaration)
                   listener: handleIdentifier(o, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, o, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, o, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(3, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/general/issue_45848_02.dart.expect b/pkg/front_end/parser_testcases/general/issue_45848_02.dart.expect
index 55f2041..f217da9 100644
--- a/pkg/front_end/parser_testcases/general/issue_45848_02.dart.expect
+++ b/pkg/front_end/parser_testcases/general/issue_45848_02.dart.expect
@@ -15,7 +15,7 @@
           handleType(bool, null)
           handleIdentifier(b1, formalParameterDeclaration)
           handleFormalParameterWithoutValue(,)
-        endFormalParameter(null, null, null, b1, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, b1, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
         beginMetadataStar(bool)
         endMetadataStar(0)
         beginFormalParameter(bool, MemberKind.TopLevelMethod, null, null, null)
@@ -24,7 +24,7 @@
           handleType(bool, null)
           handleIdentifier(b2, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, b2, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, b2, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(2, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -67,7 +67,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue(,)
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
         beginMetadataStar(int)
         endMetadataStar(0)
         beginFormalParameter(int, MemberKind.TopLevelMethod, null, null, null)
@@ -76,7 +76,7 @@
           handleType(int, null)
           handleIdentifier(y, formalParameterDeclaration)
           handleFormalParameterWithoutValue(,)
-        endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
         beginMetadataStar(Object)
         endMetadataStar(0)
         beginFormalParameter(Object, MemberKind.TopLevelMethod, null, null, null)
@@ -85,7 +85,7 @@
           handleType(Object, null)
           handleIdentifier(o, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, o, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, o, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(3, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/general/issue_45848_02.dart.intertwined.expect b/pkg/front_end/parser_testcases/general/issue_45848_02.dart.intertwined.expect
index 364c2db..dd24930 100644
--- a/pkg/front_end/parser_testcases/general/issue_45848_02.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/general/issue_45848_02.dart.intertwined.expect
@@ -19,7 +19,7 @@
           parseFormalParameters(f, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(bool)
                   listener: endMetadataStar(0)
@@ -30,8 +30,8 @@
                 ensureIdentifier(bool, formalParameterDeclaration)
                   listener: handleIdentifier(b1, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue(,)
-                listener: endFormalParameter(null, null, null, b1, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
-              parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, b1, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
+              parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(,)
                   listener: beginMetadataStar(bool)
                   listener: endMetadataStar(0)
@@ -42,7 +42,7 @@
                 ensureIdentifier(bool, formalParameterDeclaration)
                   listener: handleIdentifier(b2, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, b2, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, b2, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(2, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -128,7 +128,7 @@
           parseFormalParameters(g, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -139,8 +139,8 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue(,)
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
-              parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
+              parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(,)
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -151,8 +151,8 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(y, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue(,)
-                listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
-              parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
+              parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(,)
                   listener: beginMetadataStar(Object)
                   listener: endMetadataStar(0)
@@ -163,7 +163,7 @@
                 ensureIdentifier(Object, formalParameterDeclaration)
                   listener: handleIdentifier(o, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, o, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, o, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(3, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/general/issue_45848_02_prime.dart.expect b/pkg/front_end/parser_testcases/general/issue_45848_02_prime.dart.expect
index 6d2ad97..ab3fe72 100644
--- a/pkg/front_end/parser_testcases/general/issue_45848_02_prime.dart.expect
+++ b/pkg/front_end/parser_testcases/general/issue_45848_02_prime.dart.expect
@@ -15,7 +15,7 @@
           handleType(bool, null)
           handleIdentifier(b1, formalParameterDeclaration)
           handleFormalParameterWithoutValue(,)
-        endFormalParameter(null, null, null, b1, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, b1, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
         beginMetadataStar(bool)
         endMetadataStar(0)
         beginFormalParameter(bool, MemberKind.TopLevelMethod, null, null, null)
@@ -24,7 +24,7 @@
           handleType(bool, null)
           handleIdentifier(b2, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, b2, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, b2, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(2, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -67,7 +67,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue(,)
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
         beginMetadataStar(int)
         endMetadataStar(0)
         beginFormalParameter(int, MemberKind.TopLevelMethod, null, null, null)
@@ -76,7 +76,7 @@
           handleType(int, null)
           handleIdentifier(y, formalParameterDeclaration)
           handleFormalParameterWithoutValue(,)
-        endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
         beginMetadataStar(Object)
         endMetadataStar(0)
         beginFormalParameter(Object, MemberKind.TopLevelMethod, null, null, null)
@@ -85,7 +85,7 @@
           handleType(Object, null)
           handleIdentifier(o, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, o, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, o, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(3, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/general/issue_45848_02_prime.dart.intertwined.expect b/pkg/front_end/parser_testcases/general/issue_45848_02_prime.dart.intertwined.expect
index 917e374..cf4975c 100644
--- a/pkg/front_end/parser_testcases/general/issue_45848_02_prime.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/general/issue_45848_02_prime.dart.intertwined.expect
@@ -19,7 +19,7 @@
           parseFormalParameters(f, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(bool)
                   listener: endMetadataStar(0)
@@ -30,8 +30,8 @@
                 ensureIdentifier(bool, formalParameterDeclaration)
                   listener: handleIdentifier(b1, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue(,)
-                listener: endFormalParameter(null, null, null, b1, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
-              parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, b1, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
+              parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(,)
                   listener: beginMetadataStar(bool)
                   listener: endMetadataStar(0)
@@ -42,7 +42,7 @@
                 ensureIdentifier(bool, formalParameterDeclaration)
                   listener: handleIdentifier(b2, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, b2, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, b2, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(2, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -128,7 +128,7 @@
           parseFormalParameters(g, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -139,8 +139,8 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue(,)
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
-              parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
+              parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(,)
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -151,8 +151,8 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(y, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue(,)
-                listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
-              parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
+              parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(,)
                   listener: beginMetadataStar(Object)
                   listener: endMetadataStar(0)
@@ -163,7 +163,7 @@
                 ensureIdentifier(Object, formalParameterDeclaration)
                   listener: handleIdentifier(o, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, o, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, o, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(3, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/general/issue_45848_03.dart.expect b/pkg/front_end/parser_testcases/general/issue_45848_03.dart.expect
index 6b1850a..911ef38 100644
--- a/pkg/front_end/parser_testcases/general/issue_45848_03.dart.expect
+++ b/pkg/front_end/parser_testcases/general/issue_45848_03.dart.expect
@@ -15,7 +15,7 @@
           handleType(bool, null)
           handleIdentifier(b1, formalParameterDeclaration)
           handleFormalParameterWithoutValue(,)
-        endFormalParameter(null, null, null, b1, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, b1, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
         beginMetadataStar(bool)
         endMetadataStar(0)
         beginFormalParameter(bool, MemberKind.TopLevelMethod, null, null, null)
@@ -24,7 +24,7 @@
           handleType(bool, null)
           handleIdentifier(b2, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, b2, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, b2, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(2, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -67,7 +67,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue(,)
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
         beginMetadataStar(int)
         endMetadataStar(0)
         beginFormalParameter(int, MemberKind.TopLevelMethod, null, null, null)
@@ -76,7 +76,7 @@
           handleType(int, null)
           handleIdentifier(y, formalParameterDeclaration)
           handleFormalParameterWithoutValue(,)
-        endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
         beginMetadataStar(Object)
         endMetadataStar(0)
         beginFormalParameter(Object, MemberKind.TopLevelMethod, null, null, null)
@@ -85,7 +85,7 @@
           handleType(Object, null)
           handleIdentifier(o, formalParameterDeclaration)
           handleFormalParameterWithoutValue(,)
-        endFormalParameter(null, null, null, o, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, o, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
         beginMetadataStar(Object)
         endMetadataStar(0)
         beginFormalParameter(Object, MemberKind.TopLevelMethod, null, null, null)
@@ -94,7 +94,7 @@
           handleType(Object, null)
           handleIdentifier(p, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, p, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, p, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(4, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/general/issue_45848_03.dart.intertwined.expect b/pkg/front_end/parser_testcases/general/issue_45848_03.dart.intertwined.expect
index 9f9ba52..98b3ef5 100644
--- a/pkg/front_end/parser_testcases/general/issue_45848_03.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/general/issue_45848_03.dart.intertwined.expect
@@ -19,7 +19,7 @@
           parseFormalParameters(f, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(bool)
                   listener: endMetadataStar(0)
@@ -30,8 +30,8 @@
                 ensureIdentifier(bool, formalParameterDeclaration)
                   listener: handleIdentifier(b1, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue(,)
-                listener: endFormalParameter(null, null, null, b1, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
-              parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, b1, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
+              parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(,)
                   listener: beginMetadataStar(bool)
                   listener: endMetadataStar(0)
@@ -42,7 +42,7 @@
                 ensureIdentifier(bool, formalParameterDeclaration)
                   listener: handleIdentifier(b2, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, b2, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, b2, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(2, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -128,7 +128,7 @@
           parseFormalParameters(g, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -139,8 +139,8 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue(,)
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
-              parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
+              parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(,)
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -151,8 +151,8 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(y, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue(,)
-                listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
-              parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
+              parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(,)
                   listener: beginMetadataStar(Object)
                   listener: endMetadataStar(0)
@@ -163,8 +163,8 @@
                 ensureIdentifier(Object, formalParameterDeclaration)
                   listener: handleIdentifier(o, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue(,)
-                listener: endFormalParameter(null, null, null, o, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
-              parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, o, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
+              parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(,)
                   listener: beginMetadataStar(Object)
                   listener: endMetadataStar(0)
@@ -175,7 +175,7 @@
                 ensureIdentifier(Object, formalParameterDeclaration)
                   listener: handleIdentifier(p, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, p, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, p, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(4, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/general/issue_45848_03_prime.dart.expect b/pkg/front_end/parser_testcases/general/issue_45848_03_prime.dart.expect
index af3542b..986780c 100644
--- a/pkg/front_end/parser_testcases/general/issue_45848_03_prime.dart.expect
+++ b/pkg/front_end/parser_testcases/general/issue_45848_03_prime.dart.expect
@@ -15,7 +15,7 @@
           handleType(bool, null)
           handleIdentifier(b1, formalParameterDeclaration)
           handleFormalParameterWithoutValue(,)
-        endFormalParameter(null, null, null, b1, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, b1, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
         beginMetadataStar(bool)
         endMetadataStar(0)
         beginFormalParameter(bool, MemberKind.TopLevelMethod, null, null, null)
@@ -24,7 +24,7 @@
           handleType(bool, null)
           handleIdentifier(b2, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, b2, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, b2, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(2, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -67,7 +67,7 @@
           handleType(int, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue(,)
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
         beginMetadataStar(int)
         endMetadataStar(0)
         beginFormalParameter(int, MemberKind.TopLevelMethod, null, null, null)
@@ -76,7 +76,7 @@
           handleType(int, null)
           handleIdentifier(y, formalParameterDeclaration)
           handleFormalParameterWithoutValue(,)
-        endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
         beginMetadataStar(Object)
         endMetadataStar(0)
         beginFormalParameter(Object, MemberKind.TopLevelMethod, null, null, null)
@@ -85,7 +85,7 @@
           handleType(Object, null)
           handleIdentifier(o, formalParameterDeclaration)
           handleFormalParameterWithoutValue(,)
-        endFormalParameter(null, null, null, o, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, o, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
         beginMetadataStar(Object)
         endMetadataStar(0)
         beginFormalParameter(Object, MemberKind.TopLevelMethod, null, null, null)
@@ -94,7 +94,7 @@
           handleType(Object, null)
           handleIdentifier(p, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, p, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, p, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(4, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/general/issue_45848_03_prime.dart.intertwined.expect b/pkg/front_end/parser_testcases/general/issue_45848_03_prime.dart.intertwined.expect
index 0d4dd9d..c0c86e7 100644
--- a/pkg/front_end/parser_testcases/general/issue_45848_03_prime.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/general/issue_45848_03_prime.dart.intertwined.expect
@@ -19,7 +19,7 @@
           parseFormalParameters(f, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(bool)
                   listener: endMetadataStar(0)
@@ -30,8 +30,8 @@
                 ensureIdentifier(bool, formalParameterDeclaration)
                   listener: handleIdentifier(b1, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue(,)
-                listener: endFormalParameter(null, null, null, b1, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
-              parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, b1, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
+              parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(,)
                   listener: beginMetadataStar(bool)
                   listener: endMetadataStar(0)
@@ -42,7 +42,7 @@
                 ensureIdentifier(bool, formalParameterDeclaration)
                   listener: handleIdentifier(b2, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, b2, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, b2, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(2, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -128,7 +128,7 @@
           parseFormalParameters(g, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -139,8 +139,8 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue(,)
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
-              parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
+              parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(,)
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -151,8 +151,8 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(y, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue(,)
-                listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
-              parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, y, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
+              parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(,)
                   listener: beginMetadataStar(Object)
                   listener: endMetadataStar(0)
@@ -163,8 +163,8 @@
                 ensureIdentifier(Object, formalParameterDeclaration)
                   listener: handleIdentifier(o, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue(,)
-                listener: endFormalParameter(null, null, null, o, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
-              parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, o, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
+              parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(,)
                   listener: beginMetadataStar(Object)
                   listener: endMetadataStar(0)
@@ -175,7 +175,7 @@
                 ensureIdentifier(Object, formalParameterDeclaration)
                   listener: handleIdentifier(p, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, p, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, p, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(4, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/general/metadata.dart.expect b/pkg/front_end/parser_testcases/general/metadata.dart.expect
index 6e3fbf8d..d19f050 100644
--- a/pkg/front_end/parser_testcases/general/metadata.dart.expect
+++ b/pkg/front_end/parser_testcases/general/metadata.dart.expect
@@ -168,7 +168,7 @@
             handleType(int, null)
             handleNoName())
             handleFormalParameterWithoutValue())
-          endFormalParameter(null, null, null, ), null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+          endFormalParameter(null, null, null, ), null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
         endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
       endFunctionType(Function, null)
     endTypedef(typedef, =, ;)
@@ -230,7 +230,7 @@
             handleType(int, null)
             handleNoName())
             handleFormalParameterWithoutValue())
-          endFormalParameter(null, null, null, ), null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+          endFormalParameter(null, null, null, ), null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
         endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
       endFunctionType(Function, null)
     endTypedef(typedef, =, ;)
@@ -295,7 +295,7 @@
             handleType(int, null)
             handleNoName())
             handleFormalParameterWithoutValue())
-          endFormalParameter(null, null, null, ), null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+          endFormalParameter(null, null, null, ), null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
         endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
       endFunctionType(Function, null)
     endTypedef(typedef, =, ;)
@@ -360,7 +360,7 @@
             handleType(int, null)
             handleNoName())
             handleFormalParameterWithoutValue())
-          endFormalParameter(null, null, null, ), null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+          endFormalParameter(null, null, null, ), null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
         endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
       endFunctionType(Function, null)
     endTypedef(typedef, =, ;)
@@ -431,7 +431,7 @@
             handleType(int, null)
             handleNoName())
             handleFormalParameterWithoutValue())
-          endFormalParameter(null, null, null, ), null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+          endFormalParameter(null, null, null, ), null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
         endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
       endFunctionType(Function, null)
     endTypedef(typedef, =, ;)
@@ -505,7 +505,7 @@
             handleType(int, null)
             handleNoName())
             handleFormalParameterWithoutValue())
-          endFormalParameter(null, null, null, ), null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+          endFormalParameter(null, null, null, ), null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
         endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
       endFunctionType(Function, null)
     endTypedef(typedef, =, ;)
@@ -582,7 +582,7 @@
             handleType(int, null)
             handleNoName())
             handleFormalParameterWithoutValue())
-          endFormalParameter(null, null, null, ), null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+          endFormalParameter(null, null, null, ), null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
         endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
       endFunctionType(Function, null)
     endTypedef(typedef, =, ;)
@@ -662,7 +662,7 @@
             handleType(int, null)
             handleNoName())
             handleFormalParameterWithoutValue())
-          endFormalParameter(null, null, null, ), null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+          endFormalParameter(null, null, null, ), null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
         endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
       endFunctionType(Function, null)
     endTypedef(typedef, =, ;)
@@ -745,7 +745,7 @@
             handleType(int, null)
             handleNoName())
             handleFormalParameterWithoutValue())
-          endFormalParameter(null, null, null, ), null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+          endFormalParameter(null, null, null, ), null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
         endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
       endFunctionType(Function, null)
     endTypedef(typedef, =, ;)
@@ -831,7 +831,7 @@
             handleType(int, null)
             handleNoName())
             handleFormalParameterWithoutValue())
-          endFormalParameter(null, null, null, ), null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+          endFormalParameter(null, null, null, ), null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
         endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
       endFunctionType(Function, null)
     endTypedef(typedef, =, ;)
diff --git a/pkg/front_end/parser_testcases/general/metadata.dart.intertwined.expect b/pkg/front_end/parser_testcases/general/metadata.dart.intertwined.expect
index e61e6cb..6ce9ce4 100644
--- a/pkg/front_end/parser_testcases/general/metadata.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/general/metadata.dart.intertwined.expect
@@ -311,7 +311,7 @@
         parseFormalParametersRequiredOpt(>, MemberKind.GeneralizedFunctionType)
           parseFormalParametersRest((, MemberKind.GeneralizedFunctionType)
             listener: beginFormalParameters((, MemberKind.GeneralizedFunctionType)
-            parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+            parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
               parseMetadataStar(()
                 listener: beginMetadataStar(@)
                 parseMetadata(()
@@ -331,7 +331,7 @@
               listener: handleType(int, null)
               listener: handleNoName())
               listener: handleFormalParameterWithoutValue())
-              listener: endFormalParameter(null, null, null, ), null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+              listener: endFormalParameter(null, null, null, ), null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
             listener: endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
         listener: endFunctionType(Function, null)
         ensureSemicolon())
@@ -405,7 +405,7 @@
         parseFormalParametersRequiredOpt(>, MemberKind.GeneralizedFunctionType)
           parseFormalParametersRest((, MemberKind.GeneralizedFunctionType)
             listener: beginFormalParameters((, MemberKind.GeneralizedFunctionType)
-            parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+            parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
               parseMetadataStar(()
                 listener: beginMetadataStar(@)
                 parseMetadata(()
@@ -429,7 +429,7 @@
               listener: handleType(int, null)
               listener: handleNoName())
               listener: handleFormalParameterWithoutValue())
-              listener: endFormalParameter(null, null, null, ), null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+              listener: endFormalParameter(null, null, null, ), null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
             listener: endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
         listener: endFunctionType(Function, null)
         ensureSemicolon())
@@ -507,7 +507,7 @@
         parseFormalParametersRequiredOpt(>, MemberKind.GeneralizedFunctionType)
           parseFormalParametersRest((, MemberKind.GeneralizedFunctionType)
             listener: beginFormalParameters((, MemberKind.GeneralizedFunctionType)
-            parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+            parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
               parseMetadataStar(()
                 listener: beginMetadataStar(@)
                 parseMetadata(()
@@ -533,7 +533,7 @@
               listener: handleType(int, null)
               listener: handleNoName())
               listener: handleFormalParameterWithoutValue())
-              listener: endFormalParameter(null, null, null, ), null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+              listener: endFormalParameter(null, null, null, ), null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
             listener: endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
         listener: endFunctionType(Function, null)
         ensureSemicolon())
@@ -619,7 +619,7 @@
         parseFormalParametersRequiredOpt(>, MemberKind.GeneralizedFunctionType)
           parseFormalParametersRest((, MemberKind.GeneralizedFunctionType)
             listener: beginFormalParameters((, MemberKind.GeneralizedFunctionType)
-            parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+            parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
               parseMetadataStar(()
                 listener: beginMetadataStar(@)
                 parseMetadata(()
@@ -649,7 +649,7 @@
               listener: handleType(int, null)
               listener: handleNoName())
               listener: handleFormalParameterWithoutValue())
-              listener: endFormalParameter(null, null, null, ), null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+              listener: endFormalParameter(null, null, null, ), null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
             listener: endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
         listener: endFunctionType(Function, null)
         ensureSemicolon())
@@ -745,7 +745,7 @@
         parseFormalParametersRequiredOpt(>, MemberKind.GeneralizedFunctionType)
           parseFormalParametersRest((, MemberKind.GeneralizedFunctionType)
             listener: beginFormalParameters((, MemberKind.GeneralizedFunctionType)
-            parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+            parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
               parseMetadataStar(()
                 listener: beginMetadataStar(@)
                 parseMetadata(()
@@ -780,7 +780,7 @@
               listener: handleType(int, null)
               listener: handleNoName())
               listener: handleFormalParameterWithoutValue())
-              listener: endFormalParameter(null, null, null, ), null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+              listener: endFormalParameter(null, null, null, ), null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
             listener: endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
         listener: endFunctionType(Function, null)
         ensureSemicolon())
@@ -880,7 +880,7 @@
         parseFormalParametersRequiredOpt(>, MemberKind.GeneralizedFunctionType)
           parseFormalParametersRest((, MemberKind.GeneralizedFunctionType)
             listener: beginFormalParameters((, MemberKind.GeneralizedFunctionType)
-            parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+            parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
               parseMetadataStar(()
                 listener: beginMetadataStar(@)
                 parseMetadata(()
@@ -917,7 +917,7 @@
               listener: handleType(int, null)
               listener: handleNoName())
               listener: handleFormalParameterWithoutValue())
-              listener: endFormalParameter(null, null, null, ), null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+              listener: endFormalParameter(null, null, null, ), null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
             listener: endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
         listener: endFunctionType(Function, null)
         ensureSemicolon())
@@ -1011,7 +1011,7 @@
         parseFormalParametersRequiredOpt(>, MemberKind.GeneralizedFunctionType)
           parseFormalParametersRest((, MemberKind.GeneralizedFunctionType)
             listener: beginFormalParameters((, MemberKind.GeneralizedFunctionType)
-            parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+            parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
               parseMetadataStar(()
                 listener: beginMetadataStar(@)
                 parseMetadata(()
@@ -1045,7 +1045,7 @@
               listener: handleType(int, null)
               listener: handleNoName())
               listener: handleFormalParameterWithoutValue())
-              listener: endFormalParameter(null, null, null, ), null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+              listener: endFormalParameter(null, null, null, ), null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
             listener: endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
         listener: endFunctionType(Function, null)
         ensureSemicolon())
@@ -1145,7 +1145,7 @@
         parseFormalParametersRequiredOpt(>, MemberKind.GeneralizedFunctionType)
           parseFormalParametersRest((, MemberKind.GeneralizedFunctionType)
             listener: beginFormalParameters((, MemberKind.GeneralizedFunctionType)
-            parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+            parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
               parseMetadataStar(()
                 listener: beginMetadataStar(@)
                 parseMetadata(()
@@ -1182,7 +1182,7 @@
               listener: handleType(int, null)
               listener: handleNoName())
               listener: handleFormalParameterWithoutValue())
-              listener: endFormalParameter(null, null, null, ), null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+              listener: endFormalParameter(null, null, null, ), null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
             listener: endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
         listener: endFunctionType(Function, null)
         ensureSemicolon())
@@ -1284,7 +1284,7 @@
         parseFormalParametersRequiredOpt(>, MemberKind.GeneralizedFunctionType)
           parseFormalParametersRest((, MemberKind.GeneralizedFunctionType)
             listener: beginFormalParameters((, MemberKind.GeneralizedFunctionType)
-            parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+            parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
               parseMetadataStar(()
                 listener: beginMetadataStar(@)
                 parseMetadata(()
@@ -1322,7 +1322,7 @@
               listener: handleType(int, null)
               listener: handleNoName())
               listener: handleFormalParameterWithoutValue())
-              listener: endFormalParameter(null, null, null, ), null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+              listener: endFormalParameter(null, null, null, ), null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
             listener: endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
         listener: endFunctionType(Function, null)
         ensureSemicolon())
@@ -1430,7 +1430,7 @@
         parseFormalParametersRequiredOpt(>, MemberKind.GeneralizedFunctionType)
           parseFormalParametersRest((, MemberKind.GeneralizedFunctionType)
             listener: beginFormalParameters((, MemberKind.GeneralizedFunctionType)
-            parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+            parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
               parseMetadataStar(()
                 listener: beginMetadataStar(@)
                 parseMetadata(()
@@ -1471,7 +1471,7 @@
               listener: handleType(int, null)
               listener: handleNoName())
               listener: handleFormalParameterWithoutValue())
-              listener: endFormalParameter(null, null, null, ), null, null, FormalParameterKind.mandatory, MemberKind.GeneralizedFunctionType)
+              listener: endFormalParameter(null, null, null, ), null, null, FormalParameterKind.requiredPositional, MemberKind.GeneralizedFunctionType)
             listener: endFormalParameters(1, (, ), MemberKind.GeneralizedFunctionType)
         listener: endFunctionType(Function, null)
         ensureSemicolon())
diff --git a/pkg/front_end/parser_testcases/general/operator_01.dart.expect b/pkg/front_end/parser_testcases/general/operator_01.dart.expect
index 87f4d7f..8171688 100644
--- a/pkg/front_end/parser_testcases/general/operator_01.dart.expect
+++ b/pkg/front_end/parser_testcases/general/operator_01.dart.expect
@@ -29,7 +29,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -58,7 +58,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -87,7 +87,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -116,7 +116,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -145,7 +145,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/general/operator_01.dart.intertwined.expect b/pkg/front_end/parser_testcases/general/operator_01.dart.intertwined.expect
index 0f8ef5f..ab8e689 100644
--- a/pkg/front_end/parser_testcases/general/operator_01.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/general/operator_01.dart.intertwined.expect
@@ -44,7 +44,7 @@
                   parseFormalParameters(<, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -55,7 +55,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -102,7 +102,7 @@
                   parseFormalParameters(<<, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -113,7 +113,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -160,7 +160,7 @@
                   parseFormalParameters(>, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -171,7 +171,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -218,7 +218,7 @@
                   parseFormalParameters(>>, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -229,7 +229,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -276,7 +276,7 @@
                   parseFormalParameters(>>>, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -287,7 +287,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
diff --git a/pkg/front_end/parser_testcases/general/operator_hat_class.crash_dart.expect b/pkg/front_end/parser_testcases/general/operator_hat_class.crash_dart.expect
index 1f57566..26fedc5 100644
--- a/pkg/front_end/parser_testcases/general/operator_hat_class.crash_dart.expect
+++ b/pkg/front_end/parser_testcases/general/operator_hat_class.crash_dart.expect
@@ -34,7 +34,7 @@
                 handleType(int, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/general/operator_hat_class.crash_dart.intertwined.expect b/pkg/front_end/parser_testcases/general/operator_hat_class.crash_dart.intertwined.expect
index dec4f2e..2a09196 100644
--- a/pkg/front_end/parser_testcases/general/operator_hat_class.crash_dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/general/operator_hat_class.crash_dart.intertwined.expect
@@ -44,7 +44,7 @@
                   parseFormalParameters(^, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -55,7 +55,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
diff --git a/pkg/front_end/parser_testcases/general/try_catch.dart.expect b/pkg/front_end/parser_testcases/general/try_catch.dart.expect
index 3632e57..88d1779 100644
--- a/pkg/front_end/parser_testcases/general/try_catch.dart.expect
+++ b/pkg/front_end/parser_testcases/general/try_catch.dart.expect
@@ -21,14 +21,14 @@
                 handleNoType(()
                 handleIdentifier(e, formalParameterDeclaration)
                 handleFormalParameterWithoutValue(,)
-              endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.Catch)
+              endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.Catch)
               beginMetadataStar(s)
               endMetadataStar(0)
               beginFormalParameter(s, MemberKind.Catch, null, null, null)
                 handleNoType(,)
                 handleIdentifier(s, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, s, null, null, FormalParameterKind.mandatory, MemberKind.Catch)
+              endFormalParameter(null, null, null, s, null, null, FormalParameterKind.requiredPositional, MemberKind.Catch)
             endFormalParameters(2, (, ), MemberKind.Catch)
           endCatchClause({)
           beginBlock({, BlockKind(catch clause))
diff --git a/pkg/front_end/parser_testcases/general/try_catch.dart.intertwined.expect b/pkg/front_end/parser_testcases/general/try_catch.dart.intertwined.expect
index e241c98..69d9485 100644
--- a/pkg/front_end/parser_testcases/general/try_catch.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/general/try_catch.dart.intertwined.expect
@@ -40,7 +40,7 @@
                 parseFormalParameters(catch, MemberKind.Catch)
                   parseFormalParametersRest((, MemberKind.Catch)
                     listener: beginFormalParameters((, MemberKind.Catch)
-                    parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.Catch)
+                    parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.Catch)
                       parseMetadataStar(()
                         listener: beginMetadataStar(e)
                         listener: endMetadataStar(0)
@@ -49,8 +49,8 @@
                       ensureIdentifier((, formalParameterDeclaration)
                         listener: handleIdentifier(e, formalParameterDeclaration)
                       listener: handleFormalParameterWithoutValue(,)
-                      listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.Catch)
-                    parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.Catch)
+                      listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.Catch)
+                    parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.Catch)
                       parseMetadataStar(,)
                         listener: beginMetadataStar(s)
                         listener: endMetadataStar(0)
@@ -59,7 +59,7 @@
                       ensureIdentifier(,, formalParameterDeclaration)
                         listener: handleIdentifier(s, formalParameterDeclaration)
                       listener: handleFormalParameterWithoutValue())
-                      listener: endFormalParameter(null, null, null, s, null, null, FormalParameterKind.mandatory, MemberKind.Catch)
+                      listener: endFormalParameter(null, null, null, s, null, null, FormalParameterKind.requiredPositional, MemberKind.Catch)
                     listener: endFormalParameters(2, (, ), MemberKind.Catch)
                 listener: endCatchClause({)
                 parseBlock(), BlockKind(catch clause))
diff --git a/pkg/front_end/parser_testcases/nnbd/chained_call_01.dart.expect b/pkg/front_end/parser_testcases/nnbd/chained_call_01.dart.expect
index d504573..57b7ebe 100644
--- a/pkg/front_end/parser_testcases/nnbd/chained_call_01.dart.expect
+++ b/pkg/front_end/parser_testcases/nnbd/chained_call_01.dart.expect
@@ -15,7 +15,7 @@
           handleType(dynamic, null)
           handleIdentifier(e, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/nnbd/chained_call_01.dart.intertwined.expect b/pkg/front_end/parser_testcases/nnbd/chained_call_01.dart.intertwined.expect
index 985578d..96a8d67 100644
--- a/pkg/front_end/parser_testcases/nnbd/chained_call_01.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/nnbd/chained_call_01.dart.intertwined.expect
@@ -19,7 +19,7 @@
           parseFormalParameters(f, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(dynamic)
                   listener: endMetadataStar(0)
@@ -30,7 +30,7 @@
                 ensureIdentifier(dynamic, formalParameterDeclaration)
                   listener: handleIdentifier(e, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/nnbd/chained_call_02.dart.expect b/pkg/front_end/parser_testcases/nnbd/chained_call_02.dart.expect
index a2d09c6..ca320d5 100644
--- a/pkg/front_end/parser_testcases/nnbd/chained_call_02.dart.expect
+++ b/pkg/front_end/parser_testcases/nnbd/chained_call_02.dart.expect
@@ -15,7 +15,7 @@
           handleType(dynamic, null)
           handleIdentifier(e, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/nnbd/chained_call_02.dart.intertwined.expect b/pkg/front_end/parser_testcases/nnbd/chained_call_02.dart.intertwined.expect
index 0e86802..115149e 100644
--- a/pkg/front_end/parser_testcases/nnbd/chained_call_02.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/nnbd/chained_call_02.dart.intertwined.expect
@@ -19,7 +19,7 @@
           parseFormalParameters(f, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(dynamic)
                   listener: endMetadataStar(0)
@@ -30,7 +30,7 @@
                 ensureIdentifier(dynamic, formalParameterDeclaration)
                   listener: handleIdentifier(e, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/nnbd/chained_call_03.dart.expect b/pkg/front_end/parser_testcases/nnbd/chained_call_03.dart.expect
index b3e65bd..eccfab3 100644
--- a/pkg/front_end/parser_testcases/nnbd/chained_call_03.dart.expect
+++ b/pkg/front_end/parser_testcases/nnbd/chained_call_03.dart.expect
@@ -15,7 +15,7 @@
           handleType(dynamic, null)
           handleIdentifier(e, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/nnbd/chained_call_03.dart.intertwined.expect b/pkg/front_end/parser_testcases/nnbd/chained_call_03.dart.intertwined.expect
index 37721d8..69052ee 100644
--- a/pkg/front_end/parser_testcases/nnbd/chained_call_03.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/nnbd/chained_call_03.dart.intertwined.expect
@@ -19,7 +19,7 @@
           parseFormalParameters(f, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(dynamic)
                   listener: endMetadataStar(0)
@@ -30,7 +30,7 @@
                 ensureIdentifier(dynamic, formalParameterDeclaration)
                   listener: handleIdentifier(e, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/nnbd/chained_call_04.dart.expect b/pkg/front_end/parser_testcases/nnbd/chained_call_04.dart.expect
index 620e5ab..a69c92c 100644
--- a/pkg/front_end/parser_testcases/nnbd/chained_call_04.dart.expect
+++ b/pkg/front_end/parser_testcases/nnbd/chained_call_04.dart.expect
@@ -15,7 +15,7 @@
           handleType(dynamic, null)
           handleIdentifier(e, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/nnbd/chained_call_04.dart.intertwined.expect b/pkg/front_end/parser_testcases/nnbd/chained_call_04.dart.intertwined.expect
index 8e4acb1..5a3d80b 100644
--- a/pkg/front_end/parser_testcases/nnbd/chained_call_04.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/nnbd/chained_call_04.dart.intertwined.expect
@@ -19,7 +19,7 @@
           parseFormalParameters(f, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(dynamic)
                   listener: endMetadataStar(0)
@@ -30,7 +30,7 @@
                 ensureIdentifier(dynamic, formalParameterDeclaration)
                   listener: handleIdentifier(e, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/nnbd/chained_call_05.dart.expect b/pkg/front_end/parser_testcases/nnbd/chained_call_05.dart.expect
index 7835582..eb681bb 100644
--- a/pkg/front_end/parser_testcases/nnbd/chained_call_05.dart.expect
+++ b/pkg/front_end/parser_testcases/nnbd/chained_call_05.dart.expect
@@ -15,7 +15,7 @@
           handleType(dynamic, null)
           handleIdentifier(e, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/nnbd/chained_call_05.dart.intertwined.expect b/pkg/front_end/parser_testcases/nnbd/chained_call_05.dart.intertwined.expect
index d8d323d..1c24308c 100644
--- a/pkg/front_end/parser_testcases/nnbd/chained_call_05.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/nnbd/chained_call_05.dart.intertwined.expect
@@ -19,7 +19,7 @@
           parseFormalParameters(f, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(dynamic)
                   listener: endMetadataStar(0)
@@ -30,7 +30,7 @@
                 ensureIdentifier(dynamic, formalParameterDeclaration)
                   listener: handleIdentifier(e, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/nnbd/chained_call_06.dart.expect b/pkg/front_end/parser_testcases/nnbd/chained_call_06.dart.expect
index 89c58a5..4796374 100644
--- a/pkg/front_end/parser_testcases/nnbd/chained_call_06.dart.expect
+++ b/pkg/front_end/parser_testcases/nnbd/chained_call_06.dart.expect
@@ -15,7 +15,7 @@
           handleType(dynamic, null)
           handleIdentifier(e, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/nnbd/chained_call_06.dart.intertwined.expect b/pkg/front_end/parser_testcases/nnbd/chained_call_06.dart.intertwined.expect
index 1b8fd87..3e3a9f3 100644
--- a/pkg/front_end/parser_testcases/nnbd/chained_call_06.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/nnbd/chained_call_06.dart.intertwined.expect
@@ -19,7 +19,7 @@
           parseFormalParameters(f, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(dynamic)
                   listener: endMetadataStar(0)
@@ -30,7 +30,7 @@
                 ensureIdentifier(dynamic, formalParameterDeclaration)
                   listener: handleIdentifier(e, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/nnbd/chained_call_07.dart.expect b/pkg/front_end/parser_testcases/nnbd/chained_call_07.dart.expect
index 8d817a4..b3e4b40 100644
--- a/pkg/front_end/parser_testcases/nnbd/chained_call_07.dart.expect
+++ b/pkg/front_end/parser_testcases/nnbd/chained_call_07.dart.expect
@@ -15,7 +15,7 @@
           handleType(dynamic, null)
           handleIdentifier(e, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/nnbd/chained_call_07.dart.intertwined.expect b/pkg/front_end/parser_testcases/nnbd/chained_call_07.dart.intertwined.expect
index 9a8e4f2..f87b938 100644
--- a/pkg/front_end/parser_testcases/nnbd/chained_call_07.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/nnbd/chained_call_07.dart.intertwined.expect
@@ -19,7 +19,7 @@
           parseFormalParameters(f, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(dynamic)
                   listener: endMetadataStar(0)
@@ -30,7 +30,7 @@
                 ensureIdentifier(dynamic, formalParameterDeclaration)
                   listener: handleIdentifier(e, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/nnbd/chained_call_08.dart.expect b/pkg/front_end/parser_testcases/nnbd/chained_call_08.dart.expect
index 20ea60b..91da9ad 100644
--- a/pkg/front_end/parser_testcases/nnbd/chained_call_08.dart.expect
+++ b/pkg/front_end/parser_testcases/nnbd/chained_call_08.dart.expect
@@ -15,7 +15,7 @@
           handleType(dynamic, null)
           handleIdentifier(e, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/nnbd/chained_call_08.dart.intertwined.expect b/pkg/front_end/parser_testcases/nnbd/chained_call_08.dart.intertwined.expect
index 9fbc8ef..100b30b 100644
--- a/pkg/front_end/parser_testcases/nnbd/chained_call_08.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/nnbd/chained_call_08.dart.intertwined.expect
@@ -19,7 +19,7 @@
           parseFormalParameters(f, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(dynamic)
                   listener: endMetadataStar(0)
@@ -30,7 +30,7 @@
                 ensureIdentifier(dynamic, formalParameterDeclaration)
                   listener: handleIdentifier(e, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/nnbd/chained_call_with_index_01.dart.dart.expect b/pkg/front_end/parser_testcases/nnbd/chained_call_with_index_01.dart.dart.expect
index 50105ca..3844143 100644
--- a/pkg/front_end/parser_testcases/nnbd/chained_call_with_index_01.dart.dart.expect
+++ b/pkg/front_end/parser_testcases/nnbd/chained_call_with_index_01.dart.dart.expect
@@ -15,7 +15,7 @@
           handleType(dynamic, null)
           handleIdentifier(e, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/nnbd/chained_call_with_index_01.dart.dart.intertwined.expect b/pkg/front_end/parser_testcases/nnbd/chained_call_with_index_01.dart.dart.intertwined.expect
index 021b068..03b5b3a 100644
--- a/pkg/front_end/parser_testcases/nnbd/chained_call_with_index_01.dart.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/nnbd/chained_call_with_index_01.dart.dart.intertwined.expect
@@ -19,7 +19,7 @@
           parseFormalParameters(f, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(dynamic)
                   listener: endMetadataStar(0)
@@ -30,7 +30,7 @@
                 ensureIdentifier(dynamic, formalParameterDeclaration)
                   listener: handleIdentifier(e, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_39286.dart.expect b/pkg/front_end/parser_testcases/nnbd/issue_39286.dart.expect
index fe8f216..b239bfa 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_39286.dart.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_39286.dart.expect
@@ -15,7 +15,7 @@
           handleType(C, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_39286.dart.intertwined.expect b/pkg/front_end/parser_testcases/nnbd/issue_39286.dart.intertwined.expect
index 0109ec5..f18ffcf 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_39286.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_39286.dart.intertwined.expect
@@ -19,7 +19,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(C)
                   listener: endMetadataStar(0)
@@ -30,7 +30,7 @@
                 ensureIdentifier(C, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_39286_2.dart.expect b/pkg/front_end/parser_testcases/nnbd/issue_39286_2.dart.expect
index 024e3ff..8f68023 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_39286_2.dart.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_39286_2.dart.expect
@@ -15,7 +15,7 @@
           handleType(C, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_39286_2.dart.intertwined.expect b/pkg/front_end/parser_testcases/nnbd/issue_39286_2.dart.intertwined.expect
index c9caa2d..66561d9 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_39286_2.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_39286_2.dart.intertwined.expect
@@ -19,7 +19,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(C)
                   listener: endMetadataStar(0)
@@ -30,7 +30,7 @@
                 ensureIdentifier(C, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_39286_2_prime.dart.expect b/pkg/front_end/parser_testcases/nnbd/issue_39286_2_prime.dart.expect
index 93f0fc4..e89b97c 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_39286_2_prime.dart.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_39286_2_prime.dart.expect
@@ -15,7 +15,7 @@
           handleType(C, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_39286_2_prime.dart.intertwined.expect b/pkg/front_end/parser_testcases/nnbd/issue_39286_2_prime.dart.intertwined.expect
index 0609ba0..c16692e 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_39286_2_prime.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_39286_2_prime.dart.intertwined.expect
@@ -19,7 +19,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(C)
                   listener: endMetadataStar(0)
@@ -30,7 +30,7 @@
                 ensureIdentifier(C, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_39286_prime.dart.expect b/pkg/front_end/parser_testcases/nnbd/issue_39286_prime.dart.expect
index 7bf5d36..bbcf676 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_39286_prime.dart.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_39286_prime.dart.expect
@@ -15,7 +15,7 @@
           handleType(C, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_39286_prime.dart.intertwined.expect b/pkg/front_end/parser_testcases/nnbd/issue_39286_prime.dart.intertwined.expect
index 536cdc4..7a91e01 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_39286_prime.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_39286_prime.dart.intertwined.expect
@@ -19,7 +19,7 @@
           parseFormalParameters(test, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(C)
                   listener: endMetadataStar(0)
@@ -30,7 +30,7 @@
                 ensureIdentifier(C, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_39723.dart.expect b/pkg/front_end/parser_testcases/nnbd/issue_39723.dart.expect
index c7ab142..ee4fa8d 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_39723.dart.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_39723.dart.expect
@@ -27,7 +27,7 @@
                 handleType(int, null)
                 handleIdentifier(index, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, index, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, index, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_39723.dart.intertwined.expect b/pkg/front_end/parser_testcases/nnbd/issue_39723.dart.intertwined.expect
index 427c908..f65ed0f 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_39723.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_39723.dart.intertwined.expect
@@ -42,7 +42,7 @@
                   parseFormalParameters([], MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -53,7 +53,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(index, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, index, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, index, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_39723_prime.dart.expect b/pkg/front_end/parser_testcases/nnbd/issue_39723_prime.dart.expect
index 7637e0a..5ef701e 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_39723_prime.dart.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_39723_prime.dart.expect
@@ -27,7 +27,7 @@
                 handleType(int, null)
                 handleIdentifier(index, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, index, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, index, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_39723_prime.dart.intertwined.expect b/pkg/front_end/parser_testcases/nnbd/issue_39723_prime.dart.intertwined.expect
index 9e35037..82758c4 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_39723_prime.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_39723_prime.dart.intertwined.expect
@@ -42,7 +42,7 @@
                   parseFormalParameters([], MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -53,7 +53,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(index, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, index, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, index, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_39776.dart.expect b/pkg/front_end/parser_testcases/nnbd/issue_39776.dart.expect
index 46fbaed..b7eafc6 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_39776.dart.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_39776.dart.expect
@@ -17,7 +17,7 @@
           handleType(int, null)
           handleIdentifier(i, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, i, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, i, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginLiteralString("42")
@@ -51,7 +51,7 @@
           handleType(T, null)
           handleIdentifier(t, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, t, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, t, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       handleLiteralInt(42)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_39776.dart.intertwined.expect b/pkg/front_end/parser_testcases/nnbd/issue_39776.dart.intertwined.expect
index e532ab1..65accca 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_39776.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_39776.dart.intertwined.expect
@@ -21,7 +21,7 @@
           parseFormalParameters(foo, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -32,7 +32,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(i, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, i, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, i, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -79,7 +79,7 @@
           parseFormalParameters(>, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(T)
                   listener: endMetadataStar(0)
@@ -90,7 +90,7 @@
                 ensureIdentifier(T, formalParameterDeclaration)
                   listener: handleIdentifier(t, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, t, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, t, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_39776_prime1.dart.expect b/pkg/front_end/parser_testcases/nnbd/issue_39776_prime1.dart.expect
index 9bd99df..f7060bf 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_39776_prime1.dart.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_39776_prime1.dart.expect
@@ -17,7 +17,7 @@
           handleType(int, null)
           handleIdentifier(i, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, i, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, i, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginLiteralString("42")
@@ -51,7 +51,7 @@
           handleType(T, null)
           handleIdentifier(t, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, t, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, t, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       handleLiteralInt(42)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_39776_prime1.dart.intertwined.expect b/pkg/front_end/parser_testcases/nnbd/issue_39776_prime1.dart.intertwined.expect
index 3cd3ac7..5381dd5 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_39776_prime1.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_39776_prime1.dart.intertwined.expect
@@ -21,7 +21,7 @@
           parseFormalParameters(foo, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -32,7 +32,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(i, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, i, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, i, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -79,7 +79,7 @@
           parseFormalParameters(>, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(T)
                   listener: endMetadataStar(0)
@@ -90,7 +90,7 @@
                 ensureIdentifier(T, formalParameterDeclaration)
                   listener: handleIdentifier(t, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, t, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, t, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_39776_prime2.dart.expect b/pkg/front_end/parser_testcases/nnbd/issue_39776_prime2.dart.expect
index a0cc20d..6dda6e9 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_39776_prime2.dart.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_39776_prime2.dart.expect
@@ -17,7 +17,7 @@
           handleType(int, null)
           handleIdentifier(i, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, i, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, i, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginLiteralString("42")
@@ -51,7 +51,7 @@
           handleType(T, null)
           handleIdentifier(t, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, t, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, t, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       handleLiteralInt(42)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_39776_prime2.dart.intertwined.expect b/pkg/front_end/parser_testcases/nnbd/issue_39776_prime2.dart.intertwined.expect
index abe2650..56af9fb 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_39776_prime2.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_39776_prime2.dart.intertwined.expect
@@ -21,7 +21,7 @@
           parseFormalParameters(foo, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(int)
                   listener: endMetadataStar(0)
@@ -32,7 +32,7 @@
                 ensureIdentifier(int, formalParameterDeclaration)
                   listener: handleIdentifier(i, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, i, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, i, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -79,7 +79,7 @@
           parseFormalParameters(>, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(T)
                   listener: endMetadataStar(0)
@@ -90,7 +90,7 @@
                 ensureIdentifier(T, formalParameterDeclaration)
                   listener: handleIdentifier(t, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, t, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, t, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_39776_prime3.dart.expect b/pkg/front_end/parser_testcases/nnbd/issue_39776_prime3.dart.expect
index c5bf508..3b76c2e 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_39776_prime3.dart.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_39776_prime3.dart.expect
@@ -31,7 +31,7 @@
           handleType(T1, null)
           handleIdentifier(t1, formalParameterDeclaration)
           handleFormalParameterWithoutValue(,)
-        endFormalParameter(null, null, null, t1, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, t1, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
         beginMetadataStar(T2)
         endMetadataStar(0)
         beginFormalParameter(T2, MemberKind.TopLevelMethod, null, null, null)
@@ -40,7 +40,7 @@
           handleType(T2, null)
           handleIdentifier(t2, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, t2, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, t2, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(2, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       handleLiteralInt(42)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_39776_prime3.dart.intertwined.expect b/pkg/front_end/parser_testcases/nnbd/issue_39776_prime3.dart.intertwined.expect
index c56b490..dbdb47c 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_39776_prime3.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_39776_prime3.dart.intertwined.expect
@@ -39,7 +39,7 @@
           parseFormalParameters(>, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(T1)
                   listener: endMetadataStar(0)
@@ -50,8 +50,8 @@
                 ensureIdentifier(T1, formalParameterDeclaration)
                   listener: handleIdentifier(t1, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue(,)
-                listener: endFormalParameter(null, null, null, t1, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
-              parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, t1, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
+              parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(,)
                   listener: beginMetadataStar(T2)
                   listener: endMetadataStar(0)
@@ -62,7 +62,7 @@
                 ensureIdentifier(T2, formalParameterDeclaration)
                   listener: handleIdentifier(t2, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, t2, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, t2, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(2, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_39776_prime4.dart.expect b/pkg/front_end/parser_testcases/nnbd/issue_39776_prime4.dart.expect
index e2bd69d..42ad557 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_39776_prime4.dart.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_39776_prime4.dart.expect
@@ -31,7 +31,7 @@
           handleType(T1, null)
           handleIdentifier(t1, formalParameterDeclaration)
           handleFormalParameterWithoutValue(,)
-        endFormalParameter(null, null, null, t1, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, t1, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
         beginMetadataStar(T2)
         endMetadataStar(0)
         beginFormalParameter(T2, MemberKind.TopLevelMethod, null, null, null)
@@ -40,7 +40,7 @@
           handleType(T2, null)
           handleIdentifier(t2, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, t2, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, t2, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(2, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       handleLiteralInt(42)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_39776_prime4.dart.intertwined.expect b/pkg/front_end/parser_testcases/nnbd/issue_39776_prime4.dart.intertwined.expect
index fde2d69..598888b 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_39776_prime4.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_39776_prime4.dart.intertwined.expect
@@ -39,7 +39,7 @@
           parseFormalParameters(>, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(T1)
                   listener: endMetadataStar(0)
@@ -50,8 +50,8 @@
                 ensureIdentifier(T1, formalParameterDeclaration)
                   listener: handleIdentifier(t1, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue(,)
-                listener: endFormalParameter(null, null, null, t1, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
-              parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, t1, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
+              parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(,)
                   listener: beginMetadataStar(T2)
                   listener: endMetadataStar(0)
@@ -62,7 +62,7 @@
                 ensureIdentifier(T2, formalParameterDeclaration)
                   listener: handleIdentifier(t2, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, t2, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, t2, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(2, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_40267_lookup_plus.dart.expect b/pkg/front_end/parser_testcases/nnbd/issue_40267_lookup_plus.dart.expect
index 9dcfc3f..40b6430 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_40267_lookup_plus.dart.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_40267_lookup_plus.dart.expect
@@ -15,7 +15,7 @@
           handleType(dynamic, null)
           handleIdentifier(a, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, a, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, a, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_40267_lookup_plus.dart.intertwined.expect b/pkg/front_end/parser_testcases/nnbd/issue_40267_lookup_plus.dart.intertwined.expect
index 2f84138..7d451f6 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_40267_lookup_plus.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_40267_lookup_plus.dart.intertwined.expect
@@ -20,7 +20,7 @@
           parseFormalParameters(f, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(dynamic)
                   listener: endMetadataStar(0)
@@ -31,7 +31,7 @@
                 ensureIdentifier(dynamic, formalParameterDeclaration)
                   listener: handleIdentifier(a, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, a, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, a, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_40267_lookup_plus_plus.dart.expect b/pkg/front_end/parser_testcases/nnbd/issue_40267_lookup_plus_plus.dart.expect
index a4df5d6..4876cb5 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_40267_lookup_plus_plus.dart.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_40267_lookup_plus_plus.dart.expect
@@ -15,7 +15,7 @@
           handleType(dynamic, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue(,)
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
         beginMetadataStar(dynamic)
         endMetadataStar(0)
         beginFormalParameter(dynamic, MemberKind.TopLevelMethod, null, null, null)
@@ -24,7 +24,7 @@
           handleType(dynamic, null)
           handleIdentifier(i, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, i, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, i, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(2, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_40267_lookup_plus_plus.dart.intertwined.expect b/pkg/front_end/parser_testcases/nnbd/issue_40267_lookup_plus_plus.dart.intertwined.expect
index 872d2a6..040e0e1 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_40267_lookup_plus_plus.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_40267_lookup_plus_plus.dart.intertwined.expect
@@ -20,7 +20,7 @@
           parseFormalParameters(f, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(dynamic)
                   listener: endMetadataStar(0)
@@ -31,8 +31,8 @@
                 ensureIdentifier(dynamic, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue(,)
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
-              parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
+              parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(,)
                   listener: beginMetadataStar(dynamic)
                   listener: endMetadataStar(0)
@@ -43,7 +43,7 @@
                 ensureIdentifier(dynamic, formalParameterDeclaration)
                   listener: handleIdentifier(i, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, i, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, i, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(2, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_40267_method_call_with_type_arguments.dart.expect b/pkg/front_end/parser_testcases/nnbd/issue_40267_method_call_with_type_arguments.dart.expect
index a3bcbdb..e42484f 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_40267_method_call_with_type_arguments.dart.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_40267_method_call_with_type_arguments.dart.expect
@@ -87,7 +87,7 @@
                 handleNoType(()
                 handleIdentifier(b, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, b, null, null, FormalParameterKind.mandatory, MemberKind.Local)
+              endFormalParameter(null, null, null, b, null, null, FormalParameterKind.requiredPositional, MemberKind.Local)
             endFormalParameters(1, (, ), MemberKind.Local)
             handleAsyncModifier(null, null)
             handleRecoverableError(ExpectedBody, ;, ;)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_40267_method_call_with_type_arguments.dart.intertwined.expect b/pkg/front_end/parser_testcases/nnbd/issue_40267_method_call_with_type_arguments.dart.intertwined.expect
index dab8c9f..7578970 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_40267_method_call_with_type_arguments.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_40267_method_call_with_type_arguments.dart.intertwined.expect
@@ -148,7 +148,7 @@
                                       parseFormalParametersRequiredOpt(>, MemberKind.Local)
                                         parseFormalParametersRest((, MemberKind.Local)
                                           listener: beginFormalParameters((, MemberKind.Local)
-                                          parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.Local)
+                                          parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.Local)
                                             parseMetadataStar(()
                                               listener: beginMetadataStar(b)
                                               listener: endMetadataStar(0)
@@ -157,7 +157,7 @@
                                             ensureIdentifier((, formalParameterDeclaration)
                                               listener: handleIdentifier(b, formalParameterDeclaration)
                                             listener: handleFormalParameterWithoutValue())
-                                            listener: endFormalParameter(null, null, null, b, null, null, FormalParameterKind.mandatory, MemberKind.Local)
+                                            listener: endFormalParameter(null, null, null, b, null, null, FormalParameterKind.requiredPositional, MemberKind.Local)
                                           listener: endFormalParameters(1, (, ), MemberKind.Local)
                                       parseAsyncOptBody(), true, false)
                                         parseAsyncModifierOpt())
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_40267_plus_plus_lookup.dart.expect b/pkg/front_end/parser_testcases/nnbd/issue_40267_plus_plus_lookup.dart.expect
index 5c7e077..71d336d 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_40267_plus_plus_lookup.dart.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_40267_plus_plus_lookup.dart.expect
@@ -15,7 +15,7 @@
           handleType(dynamic, null)
           handleIdentifier(x, formalParameterDeclaration)
           handleFormalParameterWithoutValue(,)
-        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
         beginMetadataStar(dynamic)
         endMetadataStar(0)
         beginFormalParameter(dynamic, MemberKind.TopLevelMethod, null, null, null)
@@ -24,7 +24,7 @@
           handleType(dynamic, null)
           handleIdentifier(i, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, i, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, i, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(2, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_40267_plus_plus_lookup.dart.intertwined.expect b/pkg/front_end/parser_testcases/nnbd/issue_40267_plus_plus_lookup.dart.intertwined.expect
index c14c7a9..e73d955 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_40267_plus_plus_lookup.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_40267_plus_plus_lookup.dart.intertwined.expect
@@ -20,7 +20,7 @@
           parseFormalParameters(f, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(dynamic)
                   listener: endMetadataStar(0)
@@ -31,8 +31,8 @@
                 ensureIdentifier(dynamic, formalParameterDeclaration)
                   listener: handleIdentifier(x, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue(,)
-                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
-              parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
+              parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(,)
                   listener: beginMetadataStar(dynamic)
                   listener: endMetadataStar(0)
@@ -43,7 +43,7 @@
                 ensureIdentifier(dynamic, formalParameterDeclaration)
                   listener: handleIdentifier(i, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, i, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, i, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(2, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_40793.dart.expect b/pkg/front_end/parser_testcases/nnbd/issue_40793.dart.expect
index f7f74f3..fa82b45 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_40793.dart.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_40793.dart.expect
@@ -15,7 +15,7 @@
           handleType(dynamic, null)
           handleIdentifier(sample, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, sample, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, sample, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_40793.dart.intertwined.expect b/pkg/front_end/parser_testcases/nnbd/issue_40793.dart.intertwined.expect
index 4ff2191..db63fbb 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_40793.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_40793.dart.intertwined.expect
@@ -19,7 +19,7 @@
           parseFormalParameters(f, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(dynamic)
                   listener: endMetadataStar(0)
@@ -30,7 +30,7 @@
                 ensureIdentifier(dynamic, formalParameterDeclaration)
                   listener: handleIdentifier(sample, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, sample, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, sample, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_40793_prime.dart.expect b/pkg/front_end/parser_testcases/nnbd/issue_40793_prime.dart.expect
index 330ec02..b6813cd 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_40793_prime.dart.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_40793_prime.dart.expect
@@ -15,7 +15,7 @@
           handleType(dynamic, null)
           handleIdentifier(sample, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, sample, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, sample, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_40793_prime.dart.intertwined.expect b/pkg/front_end/parser_testcases/nnbd/issue_40793_prime.dart.intertwined.expect
index 1da22990..b3f8cc3 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_40793_prime.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_40793_prime.dart.intertwined.expect
@@ -19,7 +19,7 @@
           parseFormalParameters(f, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(dynamic)
                   listener: endMetadataStar(0)
@@ -30,7 +30,7 @@
                 ensureIdentifier(dynamic, formalParameterDeclaration)
                   listener: handleIdentifier(sample, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, sample, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, sample, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_40793_prime2.dart.expect b/pkg/front_end/parser_testcases/nnbd/issue_40793_prime2.dart.expect
index 8c44af9..3026351 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_40793_prime2.dart.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_40793_prime2.dart.expect
@@ -15,7 +15,7 @@
           handleType(dynamic, null)
           handleIdentifier(sample, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, sample, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, sample, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_40793_prime2.dart.intertwined.expect b/pkg/front_end/parser_testcases/nnbd/issue_40793_prime2.dart.intertwined.expect
index 9fa6435..20ab822 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_40793_prime2.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_40793_prime2.dart.intertwined.expect
@@ -19,7 +19,7 @@
           parseFormalParameters(f, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(dynamic)
                   listener: endMetadataStar(0)
@@ -30,7 +30,7 @@
                 ensureIdentifier(dynamic, formalParameterDeclaration)
                   listener: handleIdentifier(sample, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, sample, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, sample, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_40793_prime3.dart.expect b/pkg/front_end/parser_testcases/nnbd/issue_40793_prime3.dart.expect
index c790069..918518a 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_40793_prime3.dart.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_40793_prime3.dart.expect
@@ -15,7 +15,7 @@
           handleType(dynamic, null)
           handleIdentifier(sample, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, sample, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, sample, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_40793_prime3.dart.intertwined.expect b/pkg/front_end/parser_testcases/nnbd/issue_40793_prime3.dart.intertwined.expect
index 7a10fec..41a07ff 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_40793_prime3.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_40793_prime3.dart.intertwined.expect
@@ -19,7 +19,7 @@
           parseFormalParameters(f, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(dynamic)
                   listener: endMetadataStar(0)
@@ -30,7 +30,7 @@
                 ensureIdentifier(dynamic, formalParameterDeclaration)
                   listener: handleIdentifier(sample, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, sample, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, sample, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_40793_prime4.dart.expect b/pkg/front_end/parser_testcases/nnbd/issue_40793_prime4.dart.expect
index 1a04353..a1027b6 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_40793_prime4.dart.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_40793_prime4.dart.expect
@@ -15,7 +15,7 @@
           handleType(dynamic, null)
           handleIdentifier(e, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_40793_prime4.dart.intertwined.expect b/pkg/front_end/parser_testcases/nnbd/issue_40793_prime4.dart.intertwined.expect
index 944e564..82eec5f 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_40793_prime4.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_40793_prime4.dart.intertwined.expect
@@ -19,7 +19,7 @@
           parseFormalParameters(f, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(dynamic)
                   listener: endMetadataStar(0)
@@ -30,7 +30,7 @@
                 ensureIdentifier(dynamic, formalParameterDeclaration)
                   listener: handleIdentifier(e, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_40793_prime5.dart.expect b/pkg/front_end/parser_testcases/nnbd/issue_40793_prime5.dart.expect
index fa573f88..4680630 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_40793_prime5.dart.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_40793_prime5.dart.expect
@@ -15,7 +15,7 @@
           handleType(dynamic, null)
           handleIdentifier(e, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_40793_prime5.dart.intertwined.expect b/pkg/front_end/parser_testcases/nnbd/issue_40793_prime5.dart.intertwined.expect
index ae28fcf..2490973 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_40793_prime5.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_40793_prime5.dart.intertwined.expect
@@ -19,7 +19,7 @@
           parseFormalParameters(f, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(dynamic)
                   listener: endMetadataStar(0)
@@ -30,7 +30,7 @@
                 ensureIdentifier(dynamic, formalParameterDeclaration)
                   listener: handleIdentifier(e, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, e, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_40834_01.dart.expect b/pkg/front_end/parser_testcases/nnbd/issue_40834_01.dart.expect
index b03f7c8..2295a3d 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_40834_01.dart.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_40834_01.dart.expect
@@ -49,7 +49,7 @@
                 handleType(Object, ?)
                 handleIdentifier(o, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, o, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, o, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             beginInitializers(:)
               beginInitializer(x)
@@ -100,7 +100,7 @@
                 handleType(dynamic, null)
                 handleIdentifier(o, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, o, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, o, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             beginInitializers(:)
               beginInitializer(y)
@@ -164,7 +164,7 @@
                 handleType(dynamic, null)
                 handleIdentifier(o, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, o, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, o, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             beginInitializers(:)
               beginInitializer(y)
@@ -228,7 +228,7 @@
                 handleType(dynamic, null)
                 handleIdentifier(o, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, o, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, o, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             beginInitializers(:)
               beginInitializer(y)
@@ -292,7 +292,7 @@
                 handleType(dynamic, null)
                 handleIdentifier(o, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, o, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, o, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             beginInitializers(:)
               beginInitializer(y)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_40834_01.dart.intertwined.expect b/pkg/front_end/parser_testcases/nnbd/issue_40834_01.dart.intertwined.expect
index 2739059..1ea62e7 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_40834_01.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_40834_01.dart.intertwined.expect
@@ -78,7 +78,7 @@
                   parseFormalParameters(Foo, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(Object)
                           listener: endMetadataStar(0)
@@ -89,7 +89,7 @@
                         ensureIdentifier(?, formalParameterDeclaration)
                           listener: handleIdentifier(o, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, o, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, o, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   parseInitializers(:)
@@ -188,7 +188,7 @@
                   parseFormalParameters(a, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(dynamic)
                           listener: endMetadataStar(0)
@@ -199,7 +199,7 @@
                         ensureIdentifier(dynamic, formalParameterDeclaration)
                           listener: handleIdentifier(o, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, o, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, o, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   parseInitializers(:)
@@ -333,7 +333,7 @@
                   parseFormalParameters(b, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(dynamic)
                           listener: endMetadataStar(0)
@@ -344,7 +344,7 @@
                         ensureIdentifier(dynamic, formalParameterDeclaration)
                           listener: handleIdentifier(o, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, o, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, o, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   parseInitializers(:)
@@ -478,7 +478,7 @@
                   parseFormalParameters(c, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(dynamic)
                           listener: endMetadataStar(0)
@@ -489,7 +489,7 @@
                         ensureIdentifier(dynamic, formalParameterDeclaration)
                           listener: handleIdentifier(o, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, o, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, o, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   parseInitializers(:)
@@ -623,7 +623,7 @@
                   parseFormalParameters(d, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(dynamic)
                           listener: endMetadataStar(0)
@@ -634,7 +634,7 @@
                         ensureIdentifier(dynamic, formalParameterDeclaration)
                           listener: handleIdentifier(o, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, o, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, o, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   parseInitializers(:)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_40834_02.dart.expect b/pkg/front_end/parser_testcases/nnbd/issue_40834_02.dart.expect
index ef0735d..9faf112 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_40834_02.dart.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_40834_02.dart.expect
@@ -49,7 +49,7 @@
                 handleType(Object, ?)
                 handleIdentifier(o, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, o, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, o, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             beginInitializers(:)
               beginInitializer(x)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_40834_02.dart.intertwined.expect b/pkg/front_end/parser_testcases/nnbd/issue_40834_02.dart.intertwined.expect
index b8fd957..f21eff7 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_40834_02.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_40834_02.dart.intertwined.expect
@@ -78,7 +78,7 @@
                   parseFormalParameters(Foo, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(Object)
                           listener: endMetadataStar(0)
@@ -89,7 +89,7 @@
                         ensureIdentifier(?, formalParameterDeclaration)
                           listener: handleIdentifier(o, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, o, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, o, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   parseInitializers(:)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_40834_03.dart.expect b/pkg/front_end/parser_testcases/nnbd/issue_40834_03.dart.expect
index e9498ef..01b9de6 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_40834_03.dart.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_40834_03.dart.expect
@@ -49,7 +49,7 @@
                 handleType(Object, ?)
                 handleIdentifier(o, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, o, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, o, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             beginInitializers(:)
               beginInitializer(x)
@@ -109,7 +109,7 @@
                 handleType(dynamic, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -166,7 +166,7 @@
                 handleType(dynamic, null)
                 handleIdentifier(x, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_40834_03.dart.intertwined.expect b/pkg/front_end/parser_testcases/nnbd/issue_40834_03.dart.intertwined.expect
index 19ff1e8..b2028d4 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_40834_03.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_40834_03.dart.intertwined.expect
@@ -78,7 +78,7 @@
                   parseFormalParameters(Foo, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(Object)
                           listener: endMetadataStar(0)
@@ -89,7 +89,7 @@
                         ensureIdentifier(?, formalParameterDeclaration)
                           listener: handleIdentifier(o, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, o, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, o, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   parseInitializers(:)
@@ -214,7 +214,7 @@
                   parseFormalParameters(foo, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(dynamic)
                           listener: endMetadataStar(0)
@@ -225,7 +225,7 @@
                         ensureIdentifier(dynamic, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -355,7 +355,7 @@
                   parseFormalParameters(bar, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(dynamic)
                           listener: endMetadataStar(0)
@@ -366,7 +366,7 @@
                         ensureIdentifier(dynamic, formalParameterDeclaration)
                           listener: handleIdentifier(x, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, x, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_41177.dart.expect b/pkg/front_end/parser_testcases/nnbd/issue_41177.dart.expect
index 7f0bd3e..cafb81f 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_41177.dart.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_41177.dart.expect
@@ -19,7 +19,7 @@
           handleType(List, ?)
           handleIdentifier(a, formalParameterDeclaration)
           handleFormalParameterWithoutValue(,)
-        endFormalParameter(null, null, null, a, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, a, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
         beginMetadataStar(bool)
         endMetadataStar(0)
         beginFormalParameter(bool, MemberKind.TopLevelMethod, null, null, null)
@@ -28,7 +28,7 @@
           handleType(bool, ?)
           handleIdentifier(b, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, b, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, b, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(2, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_41177.dart.intertwined.expect b/pkg/front_end/parser_testcases/nnbd/issue_41177.dart.intertwined.expect
index 68efe3e..4be754e 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_41177.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_41177.dart.intertwined.expect
@@ -20,7 +20,7 @@
           parseFormalParameters(main, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(List)
                   listener: endMetadataStar(0)
@@ -35,8 +35,8 @@
                 ensureIdentifier(?, formalParameterDeclaration)
                   listener: handleIdentifier(a, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue(,)
-                listener: endFormalParameter(null, null, null, a, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
-              parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, a, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
+              parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(,)
                   listener: beginMetadataStar(bool)
                   listener: endMetadataStar(0)
@@ -47,7 +47,7 @@
                 ensureIdentifier(?, formalParameterDeclaration)
                   listener: handleIdentifier(b, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, b, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, b, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(2, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_42621.dart.expect b/pkg/front_end/parser_testcases/nnbd/issue_42621.dart.expect
index 9b642f3..1931d06 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_42621.dart.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_42621.dart.expect
@@ -24,7 +24,7 @@
           handleType(Map, null)
           handleIdentifier(json, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, json, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, json, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -105,7 +105,7 @@
           handleType(Map, null)
           handleIdentifier(json, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, json, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, json, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -186,7 +186,7 @@
           handleType(Map, null)
           handleIdentifier(json, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, json, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, json, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
@@ -268,7 +268,7 @@
           handleType(Map, null)
           handleIdentifier(json, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, json, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, json, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/nnbd/issue_42621.dart.intertwined.expect b/pkg/front_end/parser_testcases/nnbd/issue_42621.dart.intertwined.expect
index b07dc15..c621fc7 100644
--- a/pkg/front_end/parser_testcases/nnbd/issue_42621.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/nnbd/issue_42621.dart.intertwined.expect
@@ -21,7 +21,7 @@
           parseFormalParameters(method1, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(Map)
                   listener: endMetadataStar(0)
@@ -40,7 +40,7 @@
                 ensureIdentifier(>, formalParameterDeclaration)
                   listener: handleIdentifier(json, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, json, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, json, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -187,7 +187,7 @@
           parseFormalParameters(method2, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(Map)
                   listener: endMetadataStar(0)
@@ -206,7 +206,7 @@
                 ensureIdentifier(>, formalParameterDeclaration)
                   listener: handleIdentifier(json, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, json, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, json, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -353,7 +353,7 @@
           parseFormalParameters(method3, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(Map)
                   listener: endMetadataStar(0)
@@ -372,7 +372,7 @@
                 ensureIdentifier(>, formalParameterDeclaration)
                   listener: handleIdentifier(json, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, json, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, json, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
@@ -529,7 +529,7 @@
           parseFormalParameters(method4, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(Map)
                   listener: endMetadataStar(0)
@@ -548,7 +548,7 @@
                 ensureIdentifier(>, formalParameterDeclaration)
                   listener: handleIdentifier(json, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, json, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, json, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/nnbd/null_shorting_index.dart.expect b/pkg/front_end/parser_testcases/nnbd/null_shorting_index.dart.expect
index 9c2a5d2..8d87962 100644
--- a/pkg/front_end/parser_testcases/nnbd/null_shorting_index.dart.expect
+++ b/pkg/front_end/parser_testcases/nnbd/null_shorting_index.dart.expect
@@ -29,7 +29,7 @@
                 handleType(int, null)
                 handleIdentifier(index, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, index, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, index, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -56,7 +56,7 @@
                 handleType(int, null)
                 handleIdentifier(index, formalParameterDeclaration)
                 handleFormalParameterWithoutValue(,)
-              endFormalParameter(null, null, null, index, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, index, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
               beginMetadataStar(int)
               endMetadataStar(0)
               beginFormalParameter(int, MemberKind.NonStaticMethod, null, null, null)
@@ -65,7 +65,7 @@
                 handleType(int, null)
                 handleIdentifier(value, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/nnbd/null_shorting_index.dart.intertwined.expect b/pkg/front_end/parser_testcases/nnbd/null_shorting_index.dart.intertwined.expect
index 1799ed6..c607ff5 100644
--- a/pkg/front_end/parser_testcases/nnbd/null_shorting_index.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/nnbd/null_shorting_index.dart.intertwined.expect
@@ -44,7 +44,7 @@
                   parseFormalParameters([], MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -55,7 +55,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(index, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, index, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, index, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
@@ -100,7 +100,7 @@
                   parseFormalParameters([]=, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -111,8 +111,8 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(index, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue(,)
-                        listener: endFormalParameter(null, null, null, index, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
-                      parseFormalParameter(,, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, index, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
+                      parseFormalParameter(,, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(,)
                           listener: beginMetadataStar(int)
                           listener: endMetadataStar(0)
@@ -123,7 +123,7 @@
                         ensureIdentifier(int, formalParameterDeclaration)
                           listener: handleIdentifier(value, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, value, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(2, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
diff --git a/pkg/front_end/parser_testcases/nnbd/required_modifier.dart.expect b/pkg/front_end/parser_testcases/nnbd/required_modifier.dart.expect
index 0201be0..6dee6b1 100644
--- a/pkg/front_end/parser_testcases/nnbd/required_modifier.dart.expect
+++ b/pkg/front_end/parser_testcases/nnbd/required_modifier.dart.expect
@@ -113,7 +113,7 @@
             handleType(int, null)
             handleIdentifier(named, formalParameterDeclaration)
             handleFormalParameterWithoutValue(})
-          endFormalParameter(null, null, null, named, null, null, FormalParameterKind.optionalNamed, MemberKind.TopLevelMethod)
+          endFormalParameter(null, null, null, named, null, null, FormalParameterKind.requiredNamed, MemberKind.TopLevelMethod)
         endOptionalFormalParameters(1, {, })
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/nnbd/required_modifier.dart.intertwined.expect b/pkg/front_end/parser_testcases/nnbd/required_modifier.dart.intertwined.expect
index f1840da..072c202 100644
--- a/pkg/front_end/parser_testcases/nnbd/required_modifier.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/nnbd/required_modifier.dart.intertwined.expect
@@ -291,7 +291,7 @@
                   ensureIdentifier(int, formalParameterDeclaration)
                     listener: handleIdentifier(named, formalParameterDeclaration)
                   listener: handleFormalParameterWithoutValue(})
-                  listener: endFormalParameter(null, null, null, named, null, null, FormalParameterKind.optionalNamed, MemberKind.TopLevelMethod)
+                  listener: endFormalParameter(null, null, null, named, null, null, FormalParameterKind.requiredNamed, MemberKind.TopLevelMethod)
                 listener: endOptionalFormalParameters(1, {, })
               ensureCloseParen(}, ()
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
diff --git a/pkg/front_end/parser_testcases/no-triple-shift/define_triple_shift_method.dart.expect b/pkg/front_end/parser_testcases/no-triple-shift/define_triple_shift_method.dart.expect
index 677cc26..6d8f5ab 100644
--- a/pkg/front_end/parser_testcases/no-triple-shift/define_triple_shift_method.dart.expect
+++ b/pkg/front_end/parser_testcases/no-triple-shift/define_triple_shift_method.dart.expect
@@ -50,7 +50,7 @@
                 handleNoType(()
                 handleIdentifier(_, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, _, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, _, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/no-triple-shift/define_triple_shift_method.dart.intertwined.expect b/pkg/front_end/parser_testcases/no-triple-shift/define_triple_shift_method.dart.intertwined.expect
index 57d90c7..980cb19 100644
--- a/pkg/front_end/parser_testcases/no-triple-shift/define_triple_shift_method.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/no-triple-shift/define_triple_shift_method.dart.intertwined.expect
@@ -47,7 +47,7 @@
                   parseFormalParameters(>>>, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(_)
                           listener: endMetadataStar(0)
@@ -56,7 +56,7 @@
                         ensureIdentifier((, formalParameterDeclaration)
                           listener: handleIdentifier(_, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, _, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, _, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
diff --git a/pkg/front_end/parser_testcases/no-triple-shift/define_triple_shift_method_prime.dart.expect b/pkg/front_end/parser_testcases/no-triple-shift/define_triple_shift_method_prime.dart.expect
index 1bb956b..5b84bd6 100644
--- a/pkg/front_end/parser_testcases/no-triple-shift/define_triple_shift_method_prime.dart.expect
+++ b/pkg/front_end/parser_testcases/no-triple-shift/define_triple_shift_method_prime.dart.expect
@@ -27,7 +27,7 @@
                 handleNoType(()
                 handleIdentifier(_, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, _, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+              endFormalParameter(null, null, null, _, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/no-triple-shift/define_triple_shift_method_prime.dart.intertwined.expect b/pkg/front_end/parser_testcases/no-triple-shift/define_triple_shift_method_prime.dart.intertwined.expect
index 2bdab43..13d82fc 100644
--- a/pkg/front_end/parser_testcases/no-triple-shift/define_triple_shift_method_prime.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/no-triple-shift/define_triple_shift_method_prime.dart.intertwined.expect
@@ -44,7 +44,7 @@
                   parseFormalParameters(>>, MemberKind.NonStaticMethod)
                     parseFormalParametersRest((, MemberKind.NonStaticMethod)
                       listener: beginFormalParameters((, MemberKind.NonStaticMethod)
-                      parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                      parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                         parseMetadataStar(()
                           listener: beginMetadataStar(_)
                           listener: endMetadataStar(0)
@@ -53,7 +53,7 @@
                         ensureIdentifier((, formalParameterDeclaration)
                           listener: handleIdentifier(_, formalParameterDeclaration)
                         listener: handleFormalParameterWithoutValue())
-                        listener: endFormalParameter(null, null, null, _, null, null, FormalParameterKind.mandatory, MemberKind.NonStaticMethod)
+                        listener: endFormalParameter(null, null, null, _, null, null, FormalParameterKind.requiredPositional, MemberKind.NonStaticMethod)
                       listener: endFormalParameters(1, (, ), MemberKind.NonStaticMethod)
                 parseInitializersOpt())
                   listener: handleNoInitializers()
diff --git a/pkg/front_end/parser_testcases/no-triple-shift/simple_attempted_usage_of_triple_shift.dart.expect b/pkg/front_end/parser_testcases/no-triple-shift/simple_attempted_usage_of_triple_shift.dart.expect
index 7d1245d..e021f75 100644
--- a/pkg/front_end/parser_testcases/no-triple-shift/simple_attempted_usage_of_triple_shift.dart.expect
+++ b/pkg/front_end/parser_testcases/no-triple-shift/simple_attempted_usage_of_triple_shift.dart.expect
@@ -25,7 +25,7 @@
           handleType(List, null)
           handleIdentifier(arguments, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, arguments, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, arguments, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/no-triple-shift/simple_attempted_usage_of_triple_shift.dart.intertwined.expect b/pkg/front_end/parser_testcases/no-triple-shift/simple_attempted_usage_of_triple_shift.dart.intertwined.expect
index aabf7a7..f6c8349 100644
--- a/pkg/front_end/parser_testcases/no-triple-shift/simple_attempted_usage_of_triple_shift.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/no-triple-shift/simple_attempted_usage_of_triple_shift.dart.intertwined.expect
@@ -19,7 +19,7 @@
           parseFormalParameters(main, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(List)
                   listener: endMetadataStar(0)
@@ -34,7 +34,7 @@
                 ensureIdentifier(>, formalParameterDeclaration)
                   listener: handleIdentifier(arguments, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, arguments, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, arguments, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/no-triple-shift/triple_shift_not_triple_shift.dart.expect b/pkg/front_end/parser_testcases/no-triple-shift/triple_shift_not_triple_shift.dart.expect
index f167070..9e599ba 100644
--- a/pkg/front_end/parser_testcases/no-triple-shift/triple_shift_not_triple_shift.dart.expect
+++ b/pkg/front_end/parser_testcases/no-triple-shift/triple_shift_not_triple_shift.dart.expect
@@ -25,7 +25,7 @@
                 handleNoType(()
                 handleIdentifier(_, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, _, null, null, FormalParameterKind.mandatory, MemberKind.ExtensionNonStaticMethod)
+              endFormalParameter(null, null, null, _, null, null, FormalParameterKind.requiredPositional, MemberKind.ExtensionNonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.ExtensionNonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
@@ -50,7 +50,7 @@
                 handleNoType(()
                 handleIdentifier(_, formalParameterDeclaration)
                 handleFormalParameterWithoutValue())
-              endFormalParameter(null, null, null, _, null, null, FormalParameterKind.mandatory, MemberKind.ExtensionNonStaticMethod)
+              endFormalParameter(null, null, null, _, null, null, FormalParameterKind.requiredPositional, MemberKind.ExtensionNonStaticMethod)
             endFormalParameters(1, (, ), MemberKind.ExtensionNonStaticMethod)
             handleNoInitializers()
             handleAsyncModifier(null, null)
diff --git a/pkg/front_end/parser_testcases/no-triple-shift/triple_shift_not_triple_shift.dart.intertwined.expect b/pkg/front_end/parser_testcases/no-triple-shift/triple_shift_not_triple_shift.dart.intertwined.expect
index b8e8393..d3f42a9 100644
--- a/pkg/front_end/parser_testcases/no-triple-shift/triple_shift_not_triple_shift.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/no-triple-shift/triple_shift_not_triple_shift.dart.intertwined.expect
@@ -36,7 +36,7 @@
                 parseFormalParameters(>, MemberKind.ExtensionNonStaticMethod)
                   parseFormalParametersRest((, MemberKind.ExtensionNonStaticMethod)
                     listener: beginFormalParameters((, MemberKind.ExtensionNonStaticMethod)
-                    parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.ExtensionNonStaticMethod)
+                    parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.ExtensionNonStaticMethod)
                       parseMetadataStar(()
                         listener: beginMetadataStar(_)
                         listener: endMetadataStar(0)
@@ -45,7 +45,7 @@
                       ensureIdentifier((, formalParameterDeclaration)
                         listener: handleIdentifier(_, formalParameterDeclaration)
                       listener: handleFormalParameterWithoutValue())
-                      listener: endFormalParameter(null, null, null, _, null, null, FormalParameterKind.mandatory, MemberKind.ExtensionNonStaticMethod)
+                      listener: endFormalParameter(null, null, null, _, null, null, FormalParameterKind.requiredPositional, MemberKind.ExtensionNonStaticMethod)
                     listener: endFormalParameters(1, (, ), MemberKind.ExtensionNonStaticMethod)
               parseInitializersOpt())
                 listener: handleNoInitializers()
@@ -88,7 +88,7 @@
                 parseFormalParameters(call, MemberKind.ExtensionNonStaticMethod)
                   parseFormalParametersRest((, MemberKind.ExtensionNonStaticMethod)
                     listener: beginFormalParameters((, MemberKind.ExtensionNonStaticMethod)
-                    parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.ExtensionNonStaticMethod)
+                    parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.ExtensionNonStaticMethod)
                       parseMetadataStar(()
                         listener: beginMetadataStar(_)
                         listener: endMetadataStar(0)
@@ -97,7 +97,7 @@
                       ensureIdentifier((, formalParameterDeclaration)
                         listener: handleIdentifier(_, formalParameterDeclaration)
                       listener: handleFormalParameterWithoutValue())
-                      listener: endFormalParameter(null, null, null, _, null, null, FormalParameterKind.mandatory, MemberKind.ExtensionNonStaticMethod)
+                      listener: endFormalParameter(null, null, null, _, null, null, FormalParameterKind.requiredPositional, MemberKind.ExtensionNonStaticMethod)
                     listener: endFormalParameters(1, (, ), MemberKind.ExtensionNonStaticMethod)
               parseInitializersOpt())
                 listener: handleNoInitializers()
diff --git a/pkg/front_end/parser_testcases/non-nnbd/use_late_in_non_nnbd.dart.expect b/pkg/front_end/parser_testcases/non-nnbd/use_late_in_non_nnbd.dart.expect
index dd68ff3..28faad6 100644
--- a/pkg/front_end/parser_testcases/non-nnbd/use_late_in_non_nnbd.dart.expect
+++ b/pkg/front_end/parser_testcases/non-nnbd/use_late_in_non_nnbd.dart.expect
@@ -165,7 +165,7 @@
           handleType(List, null)
           handleIdentifier(args, formalParameterDeclaration)
           handleFormalParameterWithoutValue())
-        endFormalParameter(null, null, null, args, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+        endFormalParameter(null, null, null, args, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
       endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
       handleAsyncModifier(null, null)
       beginBlockFunctionBody({)
diff --git a/pkg/front_end/parser_testcases/non-nnbd/use_late_in_non_nnbd.dart.intertwined.expect b/pkg/front_end/parser_testcases/non-nnbd/use_late_in_non_nnbd.dart.intertwined.expect
index c03aca1..a09ee1e 100644
--- a/pkg/front_end/parser_testcases/non-nnbd/use_late_in_non_nnbd.dart.intertwined.expect
+++ b/pkg/front_end/parser_testcases/non-nnbd/use_late_in_non_nnbd.dart.intertwined.expect
@@ -156,7 +156,7 @@
           parseFormalParameters(main, MemberKind.TopLevelMethod)
             parseFormalParametersRest((, MemberKind.TopLevelMethod)
               listener: beginFormalParameters((, MemberKind.TopLevelMethod)
-              parseFormalParameter((, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+              parseFormalParameter((, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
                 parseMetadataStar(()
                   listener: beginMetadataStar(List)
                   listener: endMetadataStar(0)
@@ -171,7 +171,7 @@
                 ensureIdentifier(>, formalParameterDeclaration)
                   listener: handleIdentifier(args, formalParameterDeclaration)
                 listener: handleFormalParameterWithoutValue())
-                listener: endFormalParameter(null, null, null, args, null, null, FormalParameterKind.mandatory, MemberKind.TopLevelMethod)
+                listener: endFormalParameter(null, null, null, args, null, null, FormalParameterKind.requiredPositional, MemberKind.TopLevelMethod)
               listener: endFormalParameters(1, (, ), MemberKind.TopLevelMethod)
         parseAsyncModifierOpt())
           listener: handleAsyncModifier(null, null)
diff --git a/pkg/front_end/test/extensions/extensions_test.dart b/pkg/front_end/test/extensions/extensions_test.dart
index bb09833..3face97 100644
--- a/pkg/front_end/test/extensions/extensions_test.dart
+++ b/pkg/front_end/test/extensions/extensions_test.dart
@@ -233,7 +233,7 @@
     if (memberBuilder is SourceFunctionBuilder) {
       if (memberBuilder.formals != null) {
         for (FormalParameterBuilder parameter in memberBuilder.formals!) {
-          if (parameter.isRequired) {
+          if (parameter.isRequiredPositional) {
             features.addElement(Tags.builderRequiredParameters, parameter.name);
           } else if (parameter.isPositional) {
             features.addElement(
diff --git a/pkg/front_end/test/fasta/parser/type_info_test.dart b/pkg/front_end/test/fasta/parser/type_info_test.dart
index 8402482..b73a89d 100644
--- a/pkg/front_end/test/fasta/parser/type_info_test.dart
+++ b/pkg/front_end/test/fasta/parser/type_info_test.dart
@@ -776,7 +776,7 @@
       'handleType int null',
       'handleNoName )',
       'handleFormalParameterWithoutValue )',
-      'endFormalParameter null null ) FormalParameterKind.mandatory '
+      'endFormalParameter null null ) FormalParameterKind.requiredPositional '
           'MemberKind.GeneralizedFunctionType',
       'endFormalParameters 1 ( ) MemberKind.GeneralizedFunctionType',
       'endFunctionType Function null',
@@ -802,7 +802,7 @@
       'handleType int null',
       'handleNoName )',
       'handleFormalParameterWithoutValue )',
-      'endFormalParameter null null ) FormalParameterKind.mandatory'
+      'endFormalParameter null null ) FormalParameterKind.requiredPositional'
           ' MemberKind.GeneralizedFunctionType',
       'endFormalParameters 1 ( ) MemberKind.GeneralizedFunctionType',
       'endFunctionType Function null',
@@ -1471,7 +1471,8 @@
           'handleType int null',
           'handleIdentifier x formalParameterDeclaration',
           'handleFormalParameterWithoutValue )',
-          'endFormalParameter null null x FormalParameterKind.mandatory '
+          'endFormalParameter null null x '
+              'FormalParameterKind.requiredPositional '
               'MemberKind.GeneralizedFunctionType',
           'endFormalParameters 1 ( ) MemberKind.GeneralizedFunctionType',
           'endFunctionType Function null',
@@ -1484,7 +1485,8 @@
           'handleType int null',
           'handleIdentifier x formalParameterDeclaration',
           'handleFormalParameterWithoutValue )',
-          'endFormalParameter null null x FormalParameterKind.mandatory '
+          'endFormalParameter null null x '
+              'FormalParameterKind.requiredPositional '
               'MemberKind.GeneralizedFunctionType',
           'endFormalParameters 1 ( ) MemberKind.GeneralizedFunctionType',
           'endFunctionType Function null',
@@ -2422,7 +2424,8 @@
           'handleType T null',
           'handleNoName )',
           'handleFormalParameterWithoutValue )',
-          'endFormalParameter null null ) FormalParameterKind.mandatory '
+          'endFormalParameter null null ) '
+              'FormalParameterKind.requiredPositional '
               'MemberKind.GeneralizedFunctionType',
           'endFormalParameters 1 ( ) MemberKind.GeneralizedFunctionType',
           'endFunctionType Function null',
diff --git a/pkg/frontend_server/bin/frontend_server_starter.dart b/pkg/frontend_server/bin/frontend_server_starter.dart
index 2113752..82b6fb8 100644
--- a/pkg/frontend_server/bin/frontend_server_starter.dart
+++ b/pkg/frontend_server/bin/frontend_server_starter.dart
@@ -1,3 +1,4 @@
+// @dart = 2.9
 library frontend_server;
 
 import 'dart:async';
diff --git a/pkg/frontend_server/lib/frontend_server.dart b/pkg/frontend_server/lib/frontend_server.dart
index bcfd799..a9fe7dd 100644
--- a/pkg/frontend_server/lib/frontend_server.dart
+++ b/pkg/frontend_server/lib/frontend_server.dart
@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+// @dart = 2.9
 library frontend_server;
 
 import 'dart:async';
diff --git a/pkg/frontend_server/lib/src/javascript_bundle.dart b/pkg/frontend_server/lib/src/javascript_bundle.dart
index d39ee75..00ddccb 100644
--- a/pkg/frontend_server/lib/src/javascript_bundle.dart
+++ b/pkg/frontend_server/lib/src/javascript_bundle.dart
@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+// @dart = 2.9
 import 'dart:convert';
 import 'dart:io';
 
diff --git a/pkg/frontend_server/lib/src/strong_components.dart b/pkg/frontend_server/lib/src/strong_components.dart
index 4c010a8..0711f2d 100644
--- a/pkg/frontend_server/lib/src/strong_components.dart
+++ b/pkg/frontend_server/lib/src/strong_components.dart
@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+// @dart = 2.9
 import 'package:kernel/ast.dart';
 import 'package:kernel/util/graph.dart';
 
diff --git a/pkg/frontend_server/pubspec.yaml b/pkg/frontend_server/pubspec.yaml
index 9985e92..62f7446 100644
--- a/pkg/frontend_server/pubspec.yaml
+++ b/pkg/frontend_server/pubspec.yaml
@@ -4,7 +4,7 @@
 publish_to: none
 
 environment:
-  sdk: "^2.7.0"
+  sdk: "^2.15.0"
 
 dependencies:
   args: ^2.0.0
diff --git a/pkg/frontend_server/test/frontend_server_flutter.dart b/pkg/frontend_server/test/frontend_server_flutter.dart
index 78c9a7b..e0132b3 100644
--- a/pkg/frontend_server/test/frontend_server_flutter.dart
+++ b/pkg/frontend_server/test/frontend_server_flutter.dart
@@ -1,3 +1,4 @@
+// @dart = 2.9
 import 'dart:async' show StreamController;
 import 'dart:convert' show utf8, LineSplitter;
 import 'dart:io' show Directory, File, FileSystemEntity, IOSink, exitCode;
diff --git a/pkg/frontend_server/test/frontend_server_flutter_suite.dart b/pkg/frontend_server/test/frontend_server_flutter_suite.dart
index 36ae561..0a6b249 100644
--- a/pkg/frontend_server/test/frontend_server_flutter_suite.dart
+++ b/pkg/frontend_server/test/frontend_server_flutter_suite.dart
@@ -2,6 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE.md file.
 
+// @dart = 2.9
 import 'dart:async' show StreamSubscription, Timer;
 import 'dart:convert' show jsonEncode;
 import 'dart:io' show File, exitCode;
diff --git a/pkg/frontend_server/test/frontend_server_test.dart b/pkg/frontend_server/test/frontend_server_test.dart
index 1d7e607..d34b067 100644
--- a/pkg/frontend_server/test/frontend_server_test.dart
+++ b/pkg/frontend_server/test/frontend_server_test.dart
@@ -1,3 +1,4 @@
+// @dart = 2.9
 import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
diff --git a/pkg/frontend_server/test/src/javascript_bundle_test.dart b/pkg/frontend_server/test/src/javascript_bundle_test.dart
index 69a7156..488e986 100644
--- a/pkg/frontend_server/test/src/javascript_bundle_test.dart
+++ b/pkg/frontend_server/test/src/javascript_bundle_test.dart
@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+// @dart = 2.9
 import 'dart:convert';
 import 'dart:io';
 
diff --git a/pkg/frontend_server/test/src/strong_components_test.dart b/pkg/frontend_server/test/src/strong_components_test.dart
index 9bb6596..2281e82 100644
--- a/pkg/frontend_server/test/src/strong_components_test.dart
+++ b/pkg/frontend_server/test/src/strong_components_test.dart
@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+// @dart = 2.9
 import 'package:frontend_server/src/strong_components.dart';
 import 'package:kernel/ast.dart';
 import 'package:test/test.dart';
diff --git a/sdk/lib/isolate/isolate.dart b/sdk/lib/isolate/isolate.dart
index d1ff9fc..8098a0f 100644
--- a/sdk/lib/isolate/isolate.dart
+++ b/sdk/lib/isolate/isolate.dart
@@ -144,113 +144,6 @@
   /// inspect the isolate and see uncaught errors or when it terminates.
   Isolate(this.controlPort, {this.pauseCapability, this.terminateCapability});
 
-  /// Runs [computation] in a new isolate and returns the result.
-  ///
-  /// ```dart
-  /// int slowFib(int n) =>
-  ///     n <= 1 ? 1 : slowFib(n - 1) + slowFib(n - 2);
-  ///
-  /// // Compute without blocking current isolate.
-  /// var fib40 = await Isolate.run(() => slowFib(40));
-  /// ```
-  ///
-  /// If [computation] is asynchronous (returns a `Future<R>`) then
-  /// that future is awaited in the new isolate, completing the entire
-  /// asynchronous computation, before returning the result.
-  ///
-  /// ```dart
-  /// int slowFib(int n) =>
-  ///     n <= 1 ? 1 : slowFib(n - 1) + slowFib(n - 2);
-  /// Stream<int> fibStream() async* {
-  ///   for (var i = 0;; i++) yield slowFib(i);
-  /// }
-  ///
-  /// // Returns `Future<int>`.
-  /// var fib40 = await Isolate.run(() => fibStream().elementAt(40));
-  /// ```
-  ///
-  /// If [computation] throws, the isolate is terminated and this
-  /// function throws the same error.
-  ///
-  /// ```dart import:convert
-  /// Future<int> eventualError() async {
-  ///   await Future.delayed(const Duration(seconds: 1));
-  ///   throw StateError("In a bad state!");
-  /// }
-  ///
-  /// try {
-  ///   await Isolate.run(eventualError);
-  /// } on StateError catch (e, s) {
-  ///   print(e.message); // In a bad state!
-  ///   print(LineSplitter.split("$s").first); // Contains "eventualError"
-  /// }
-  /// ```
-  /// Any uncaught asynchronous errors will terminate the computation as well,
-  /// but will be reported as a [RemoteError] because [addErrorListener]
-  /// does not provide the original error object.
-  ///
-  /// The result is sent using [exit], which means it's sent to this
-  /// isolate without copying.
-  ///
-  /// The [computation] function and its result (or error) must be
-  /// sendable between isolates.
-  ///
-  /// The [debugName] is only used to name the new isolate for debugging.
-  @Since("2.17")
-  static Future<R> run<R>(FutureOr<R> computation(), {String? debugName}) {
-    var result = Completer<R>();
-    var resultPort = RawReceivePort();
-    resultPort.handler = (response) {
-      resultPort.close();
-      if (response == null) {
-        // onExit handler message, isolate terminated without sending result.
-        result.completeError(
-            RemoteError("Computation ended without result", ""),
-            StackTrace.empty);
-        return;
-      }
-      var list = response as List<Object?>;
-      if (list.length == 2) {
-        var remoteError = list[0];
-        var remoteStack = list[1];
-        if (remoteStack is StackTrace) {
-          // Typed error.
-          result.completeError(remoteError!, remoteStack);
-        } else {
-          // onError handler message, uncaught async error.
-          // Both values are strings, so calling `toString` is efficient.
-          var error =
-              RemoteError(remoteError.toString(), remoteStack.toString());
-          result.completeError(error, error.stackTrace);
-        }
-      } else {
-        assert(list.length == 1);
-        result.complete(list[0] as R);
-      }
-    };
-    try {
-      Isolate.spawn(_RemoteRunner._remoteExecute,
-              _RemoteRunner<R>(computation, resultPort.sendPort),
-              onError: resultPort.sendPort,
-              onExit: resultPort.sendPort,
-              errorsAreFatal: true,
-              debugName: debugName)
-          .then<void>((_) {}, onError: (error, stack) {
-        // Sending the computation failed asynchronously.
-        // Do not expect a response, report the error asynchronously.
-        resultPort.close();
-        result.completeError(error, stack);
-      });
-    } on Object {
-      // Sending the computation failed synchronously.
-      // This is not expected to happen, but if it does,
-      // the synchronous error is respected and rethrown synchronously.
-      resultPort.close();
-      rethrow;
-    }
-    return result.future;
-  }
-
   /// An [Isolate] object representing the current isolate.
   ///
   /// The current isolate for code using [current]
@@ -905,62 +798,3 @@
   /// transferable bytes, even if the calls occur in different isolates.
   ByteBuffer materialize();
 }
-
-/// Parameter object used by [Isolate.run].
-///
-/// The [_remoteExecute] function is run in a new isolate with a
-/// [_RemoteRunner] object as argument.
-class _RemoteRunner<R> {
-  /// User computation to run.
-  final FutureOr<R> Function() computation;
-
-  /// Port to send isolate computation result on.
-  ///
-  /// Only one object is ever sent on this port.
-  /// If the value is `null`, it is sent by the isolate's "on-exit" handler
-  /// when the isolate terminates without otherwise sending value.
-  /// If the value is a list with one element,
-  /// then it is the result value of the computation.
-  /// Otherwise it is a list with two elements representing an error.
-  /// If the error is sent by the isolate's "on-error" uncaught error handler,
-  /// then the list contains two strings. This also terminates the isolate.
-  /// If sent manually by this class, after capturing the error,
-  /// the list contains one non-`null` [Object] and one [StackTrace].
-  final SendPort resultPort;
-
-  _RemoteRunner(this.computation, this.resultPort);
-
-  /// Run in a new isolate to get the result of [computation].
-  ///
-  /// The result is sent back on [resultPort] as a single-element list.
-  /// A two-element list sent on the same port is an error result.
-  /// When sent by this function, it's always an object and a [StackTrace].
-  /// (The same port listens on uncaught errors from the isolate, which
-  /// sends two-element lists containing [String]s instead).
-  static void _remoteExecute(_RemoteRunner<Object?> runner) {
-    runner._run();
-  }
-
-  void _run() async {
-    R result;
-    try {
-      var potentiallyAsyncResult = computation();
-      if (potentiallyAsyncResult is Future<R>) {
-        result = await potentiallyAsyncResult;
-      } else {
-        result = potentiallyAsyncResult;
-      }
-    } catch (e, s) {
-      // If sending fails, the error becomes an uncaught error.
-      Isolate.exit(resultPort, _list2(e, s));
-    }
-    Isolate.exit(resultPort, _list1(result));
-  }
-
-  /// Helper function to create a one-element non-growable list.
-  static List<Object?> _list1(Object? value) => List.filled(1, value);
-
-  /// Helper function to create a two-element non-growable list.
-  static List<Object?> _list2(Object? value1, Object? value2) =>
-      List.filled(2, value1)..[1] = value2;
-}
diff --git a/tests/language/inference_update_1/horizontal_inference_enabled_test.dart b/tests/language/inference_update_1/horizontal_inference_enabled_test.dart
index fc18f0f..33b32df 100644
--- a/tests/language/inference_update_1/horizontal_inference_enabled_test.dart
+++ b/tests/language/inference_update_1/horizontal_inference_enabled_test.dart
@@ -53,4 +53,58 @@
   a.expectStaticType<Exactly<int>>();
 }
 
+// The test cases below exercise situations where there are multiple closures in
+// the invocation, and they need to be inferred in the right order.
+
+testClosureAsParameterType(U Function<T, U>(T, U Function(T)) f) {
+  f(() => 0, (h) => [h()]..expectStaticType<Exactly<List<int>>>())
+      .expectStaticType<Exactly<List<int>>>();
+}
+
+testPropagateToEarlierClosure(U Function<T, U>(U Function(T), T Function()) f) {
+  f((x) => [x]..expectStaticType<Exactly<List<int>>>(), () => 0)
+      .expectStaticType<Exactly<List<int>>>();
+}
+
+testPropagateToLaterClosure(U Function<T, U>(T Function(), U Function(T)) f) {
+  f(() => 0, (x) => [x]..expectStaticType<Exactly<List<int>>>())
+      .expectStaticType<Exactly<List<int>>>();
+}
+
+testLongDepedencyChain(
+    V Function<T, U, V>(T Function(), U Function(T), V Function(U)) f) {
+  f(() => [0], (x) => x.single..expectStaticType<Exactly<int>>(),
+          (y) => {y}..expectStaticType<Exactly<Set<int>>>())
+      .expectStaticType<Exactly<Set<int>>>();
+}
+
+testDependencyCycle(Map<T, U> Function<T, U>(T Function(U), U Function(T)) f) {
+  f((x) => [x]..expectStaticType<Exactly<List<Object?>>>(),
+          (y) => {y}..expectStaticType<Exactly<Set<Object?>>>())
+      .expectStaticType<Exactly<Map<List<Object?>, Set<Object?>>>>();
+}
+
+testPropagateFromContravariantReturnType(
+    U Function<T, U>(void Function(T) Function(), U Function(T)) f) {
+  f(() => (int i) {}, (x) => [x]..expectStaticType<Exactly<List<int>>>())
+      .expectStaticType<Exactly<List<int>>>();
+}
+
+testPropagateToContravariantParameterType(
+    U Function<T, U>(T Function(), U Function(void Function(T))) f) {
+  f(() => 0, (x) => [x]..expectStaticType<Exactly<List<void Function(int)>>>())
+      .expectStaticType<Exactly<List<void Function(int)>>>();
+}
+
+testReturnTypeRefersToMultipleTypeVars(
+    void Function<T, U>(
+            Map<T, U> Function(), void Function(T), void Function(U))
+        f) {
+  f(() => {0: ''}, (k) {
+    k.expectStaticType<Exactly<int>>();
+  }, (v) {
+    v.expectStaticType<Exactly<String>>();
+  });
+}
+
 main() {}
diff --git a/tests/lib/isolate/isolate_run_test.dart b/tests/lib/isolate/isolate_run_test.dart
deleted file mode 100644
index b598029..0000000
--- a/tests/lib/isolate/isolate_run_test.dart
+++ /dev/null
@@ -1,125 +0,0 @@
-// Copyright (c) 2022, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-import 'dart:isolate';
-import 'dart:async';
-import 'package:async_helper/async_helper.dart';
-import 'package:expect/expect.dart';
-
-void main() async {
-  asyncStart();
-  // Sending result back.
-  await testValue();
-  await testAsyncValue();
-  // Sending error from computation back.
-  await testError();
-  await testAsyncError();
-  // Sending uncaught async error back.
-  await testUncaughtError();
-  // Not sending anything back before isolate dies.
-  await testIsolateHangs();
-  await testIsolateKilled();
-  await testIsolateExits();
-  // Failing to start.
-  await testInvalidMessage();
-  asyncEnd();
-}
-
-final StackTrace stack = StackTrace.fromString("Known Stacktrace");
-final ArgumentError error = ArgumentError.value(42, "name");
-
-var variable = 0;
-
-Future<void> testValue() async {
-  var value = await Isolate.run<int>(() {
-    variable = 1; // Changed in other isolate!
-    Expect.equals(1, variable);
-    return 42;
-  });
-  Expect.equals(42, value);
-  Expect.equals(0, variable);
-}
-
-Future<void> testAsyncValue() async {
-  var value = await Isolate.run<int>(() async {
-    variable = 1;
-    return 42;
-  });
-  Expect.equals(42, value);
-  Expect.equals(0, variable);
-}
-
-Future<void> testError() async {
-  var e = await asyncExpectThrows<ArgumentError>(Isolate.run<int>(() {
-    variable = 1;
-    Error.throwWithStackTrace(error, stack);
-  }));
-  Expect.equals(42, e.invalidValue);
-  Expect.equals("name", e.name);
-  Expect.equals(0, variable);
-}
-
-Future<void> testAsyncError() async {
-  var e = await asyncExpectThrows<ArgumentError>(Isolate.run<int>(() async {
-    variable = 1;
-    Error.throwWithStackTrace(error, stack);
-  }));
-  Expect.equals(42, e.invalidValue);
-  Expect.equals("name", e.name);
-  Expect.equals(0, variable);
-}
-
-Future<void> testUncaughtError() async {
-  var e = await asyncExpectThrows<RemoteError>(Isolate.run<int>(() async {
-    variable = 1;
-    unawaited(Future.error(error, stack)); // Uncaught error
-    await Completer().future; // Never completes.
-    return -1;
-  }));
-
-  Expect.type<RemoteError>(e);
-  Expect.equals(error.toString(), e.toString());
-  Expect.equals(0, variable);
-}
-
-Future<void> testIsolateHangs() async {
-  var e = await asyncExpectThrows<RemoteError>(Isolate.run<int>(() async {
-    variable = 1;
-    await Completer<Never>().future; // Never completes.
-    // Isolate should end while hanging here, because its event loop is empty.
-  }));
-  Expect.type<RemoteError>(e);
-  Expect.equals("Computation ended without result", e.toString());
-  Expect.equals(0, variable);
-}
-
-Future<void> testIsolateKilled() async {
-  var e = await asyncExpectThrows<RemoteError>(Isolate.run<int>(() async {
-    variable = 1;
-    Isolate.current.kill(); // Send kill request.
-    await Completer<Never>().future; // Never completes.
-    // Isolate should get killed while hanging here.
-  }));
-  Expect.type<RemoteError>(e);
-  Expect.equals("Computation ended without result", e.toString());
-  Expect.equals(0, variable);
-}
-
-Future<void> testIsolateExits() async {
-  var e = await asyncExpectThrows<RemoteError>(Isolate.run<int>(() async {
-    variable = 1;
-    Isolate.exit(); // Dies here without sending anything back.
-  }));
-  Expect.type<RemoteError>(e);
-  Expect.equals("Computation ended without result", e.toString());
-  Expect.equals(0, variable);
-}
-
-Future<void> testInvalidMessage() async {
-  // Regression test for http://dartbug.com/48516
-  var unsendable = RawReceivePort();
-  await asyncExpectThrows<Error>(Isolate.run<void>(() => unsendable));
-  unsendable.close();
-  // Test should not hang.
-}
diff --git a/tests/lib_2/isolate/isolate_run_test.dart b/tests/lib_2/isolate/isolate_run_test.dart
deleted file mode 100644
index cad8d04..0000000
--- a/tests/lib_2/isolate/isolate_run_test.dart
+++ /dev/null
@@ -1,127 +0,0 @@
-// Copyright (c) 2022, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-// @dart = 2.9
-
-import 'dart:isolate';
-import 'dart:async';
-import 'package:async_helper/async_helper.dart';
-import 'package:expect/expect.dart';
-
-void main() async {
-  asyncStart();
-  // Sending result back.
-  await testValue();
-  await testAsyncValue();
-  // Sending error from computation back.
-  await testError();
-  await testAsyncError();
-  // Sending uncaught async error back.
-  await testUncaughtError();
-  // Not sending anything back before isolate dies.
-  await testIsolateHangs();
-  await testIsolateKilled();
-  await testIsolateExits();
-  // Failing to start.
-  await testInvalidMessage();
-  asyncEnd();
-}
-
-final StackTrace stack = StackTrace.fromString("Known Stacktrace");
-final ArgumentError error = ArgumentError.value(42, "name");
-
-var variable = 0;
-
-Future<void> testValue() async {
-  var value = await Isolate.run<int>(() {
-    variable = 1; // Changed in other isolate!
-    Expect.equals(1, variable);
-    return 42;
-  });
-  Expect.equals(42, value);
-  Expect.equals(0, variable);
-}
-
-Future<void> testAsyncValue() async {
-  var value = await Isolate.run<int>(() async {
-    variable = 1;
-    return 42;
-  });
-  Expect.equals(42, value);
-  Expect.equals(0, variable);
-}
-
-Future<void> testError() async {
-  var e = await asyncExpectThrows<ArgumentError>(Isolate.run<int>(() {
-    variable = 1;
-    Error.throwWithStackTrace(error, stack);
-  }));
-  Expect.equals(42, e.invalidValue);
-  Expect.equals("name", e.name);
-  Expect.equals(0, variable);
-}
-
-Future<void> testAsyncError() async {
-  var e = await asyncExpectThrows<ArgumentError>(Isolate.run<int>(() async {
-    variable = 1;
-    Error.throwWithStackTrace(error, stack);
-  }));
-  Expect.equals(42, e.invalidValue);
-  Expect.equals("name", e.name);
-  Expect.equals(0, variable);
-}
-
-Future<void> testUncaughtError() async {
-  var e = await asyncExpectThrows<RemoteError>(Isolate.run<int>(() async {
-    variable = 1;
-    unawaited(Future.error(error, stack)); // Uncaught error
-    await Completer().future; // Never completes.
-    return -1;
-  }));
-
-  Expect.type<RemoteError>(e);
-  Expect.equals(error.toString(), e.toString());
-  Expect.equals(0, variable);
-}
-
-Future<void> testIsolateHangs() async {
-  var e = await asyncExpectThrows<RemoteError>(Isolate.run<int>(() async {
-    variable = 1;
-    await Completer<Never>().future; // Never completes.
-    // Isolate should end while hanging here, because its event loop is empty.
-  }));
-  Expect.type<RemoteError>(e);
-  Expect.equals("Computation ended without result", e.toString());
-  Expect.equals(0, variable);
-}
-
-Future<void> testIsolateKilled() async {
-  var e = await asyncExpectThrows<RemoteError>(Isolate.run<int>(() async {
-    variable = 1;
-    Isolate.current.kill(); // Send kill request.
-    await Completer<Never>().future; // Never completes.
-    // Isolate should get killed while hanging here.
-  }));
-  Expect.type<RemoteError>(e);
-  Expect.equals("Computation ended without result", e.toString());
-  Expect.equals(0, variable);
-}
-
-Future<void> testIsolateExits() async {
-  var e = await asyncExpectThrows<RemoteError>(Isolate.run<int>(() async {
-    variable = 1;
-    Isolate.exit(); // Dies here without sending anything back.
-  }));
-  Expect.type<RemoteError>(e);
-  Expect.equals("Computation ended without result", e.toString());
-  Expect.equals(0, variable);
-}
-
-Future<void> testInvalidMessage() async {
-  // Regression test for http://dartbug.com/48516
-  var unsendable = RawReceivePort();
-  await asyncExpectThrows<Error>(Isolate.run<void>(() => unsendable));
-  unsendable.close();
-  // Test should not hang.
-}
diff --git a/tools/VERSION b/tools/VERSION
index 743ffed..825b9b2 100644
--- a/tools/VERSION
+++ b/tools/VERSION
@@ -27,5 +27,5 @@
 MAJOR 2
 MINOR 17
 PATCH 0
-PRERELEASE 260
+PRERELEASE 261
 PRERELEASE_PATCH 0
\ No newline at end of file