[cfe] Allow named arguments anywhere by the CFE Change-Id: I36ecafe821fe328bd27cb40dafca78ad0bf5dd81 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/214803 Commit-Queue: Chloe Stefantsova <dmitryas@google.com> Reviewed-by: Johnni Winther <johnniwinther@google.com>

diff --git a/pkg/front_end/lib/src/api_prototype/compiler_options.dart b/pkg/front_end/lib/src/api_prototype/compiler_options.dart
index 370f581..7f14df8 100644
--- a/pkg/front_end/lib/src/api_prototype/compiler_options.dart
+++ b/pkg/front_end/lib/src/api_prototype/compiler_options.dart

@@ -126,6 +126,8 @@
   Map<ExperimentalFlag, Version>? experimentEnabledVersionForTesting;
   Map<ExperimentalFlag, Version>? experimentReleasedVersionForTesting;
 
+  bool enableUnscheduledExperiments = false;
+
   /// Environment map used when evaluating `bool.fromEnvironment`,
   /// `int.fromEnvironment` and `String.fromEnvironment` during constant
   /// evaluation. If the map is `null`, all environment constants will be left
@@ -357,6 +359,9 @@
     if (currentSdkVersion != other.currentSdkVersion) return false;
     if (emitDeps != other.emitDeps) return false;
     if (!equalSets(invocationModes, other.invocationModes)) return false;
+    if (enableUnscheduledExperiments != other.enableUnscheduledExperiments) {
+      return false;
+    }
 
     return true;
   }

diff --git a/pkg/front_end/lib/src/base/command_line_options.dart b/pkg/front_end/lib/src/base/command_line_options.dart
index 46aabec..a8c7e9b 100644
--- a/pkg/front_end/lib/src/base/command_line_options.dart
+++ b/pkg/front_end/lib/src/base/command_line_options.dart

@@ -29,6 +29,8 @@
   static const String compileSdk = "--compile-sdk";
   static const String dumpIr = "--dump-ir";
   static const String enableExperiment = "--enable-experiment";
+  static const String enableUnscheduledExperiments =
+      "--enable-unscheduled-experiments";
   static const String excludeSource = "--exclude-source";
   static const String omitPlatform = "--omit-platform";
   static const String fatal = "--fatal";
@@ -59,6 +61,8 @@
       const Option(Flags.dumpIr, const BoolValue(false));
   static const Option<List<String>?> enableExperiment =
       const Option(Flags.enableExperiment, const StringListValue());
+  static const Option<bool> enableUnscheduledExperiments =
+      const Option(Flags.enableUnscheduledExperiments, const BoolValue(false));
   static const Option<bool> excludeSource =
       const Option(Flags.excludeSource, const BoolValue(false));
   static const Option<bool> omitPlatform =

diff --git a/pkg/front_end/lib/src/base/processed_options.dart b/pkg/front_end/lib/src/base/processed_options.dart
index e6a3ec0..8601e94 100644
--- a/pkg/front_end/lib/src/base/processed_options.dart
+++ b/pkg/front_end/lib/src/base/processed_options.dart

@@ -186,6 +186,8 @@
 
   bool get warnOnReachabilityCheck => _raw.warnOnReachabilityCheck;
 
+  bool get enableUnscheduledExperiments => _raw.enableUnscheduledExperiments;
+
   /// The entry-points provided to the compiler.
   final List<Uri> inputs;
 

diff --git a/pkg/front_end/lib/src/fasta/builder/factory_builder.dart b/pkg/front_end/lib/src/fasta/builder/factory_builder.dart
index d19bcde..2561223 100644
--- a/pkg/front_end/lib/src/fasta/builder/factory_builder.dart
+++ b/pkg/front_end/lib/src/fasta/builder/factory_builder.dart

@@ -401,7 +401,7 @@
         unhandled("${targetBuilder.runtimeType}", "buildOutlineExpressions",
             charOffset, fileUri);
       }
-      Arguments targetInvocationArguments;
+      ArgumentsImpl targetInvocationArguments;
       {
         List<Expression> positionalArguments = <Expression>[];
         for (VariableDeclaration parameter

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 3bf60515..15ba274 100644
--- a/pkg/front_end/lib/src/fasta/kernel/body_builder.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/body_builder.dart

@@ -451,6 +451,11 @@
     return libraryBuilder.enableConstructorTearOffsInLibrary;
   }
 
+  @override
+  bool get enableNamedArgumentsAnywhereInLibrary {
+    return libraryBuilder.enableNamedArgumentsAnywhereInLibrary;
+  }
+
   void _enterLocalState({bool inLateLocalInitializer: false}) {
     _localInitializerState =
         _localInitializerState.prepend(inLateLocalInitializer);
@@ -1700,35 +1705,72 @@
       push(new ParserRecovery(beginToken.charOffset));
       return;
     }
+    List<Object?>? argumentsOriginalOrder;
+    if (libraryBuilder.enableNamedArgumentsAnywhereInLibrary) {
+      argumentsOriginalOrder = new List<Object?>.from(arguments);
+    }
     int firstNamedArgumentIndex = arguments.length;
+    int positionalCount = 0;
+    bool hasNamedBeforePositional = false;
     for (int i = 0; i < arguments.length; i++) {
       Object? node = arguments[i];
       if (node is NamedExpression) {
         firstNamedArgumentIndex =
             i < firstNamedArgumentIndex ? i : firstNamedArgumentIndex;
       } else {
+        positionalCount++;
         Expression argument = toValue(node);
         arguments[i] = argument;
+        argumentsOriginalOrder?[i] = argument;
         if (i > firstNamedArgumentIndex) {
-          arguments[i] = new NamedExpression(
-              "#$i",
-              buildProblem(fasta.messageExpectedNamedArgument,
-                  argument.fileOffset, noLength))
-            ..fileOffset = beginToken.charOffset;
+          hasNamedBeforePositional = true;
+          if (!libraryBuilder.enableNamedArgumentsAnywhereInLibrary) {
+            arguments[i] = new NamedExpression(
+                "#$i",
+                buildProblem(fasta.messageExpectedNamedArgument,
+                    argument.fileOffset, noLength))
+              ..fileOffset = beginToken.charOffset;
+          }
         }
       }
     }
+    if (!hasNamedBeforePositional) {
+      argumentsOriginalOrder = null;
+    }
     if (firstNamedArgumentIndex < arguments.length) {
-      List<Expression> positional = new List<Expression>.from(
-          arguments.getRange(0, firstNamedArgumentIndex));
-      List<NamedExpression> named = new List<NamedExpression>.from(
-          arguments.getRange(firstNamedArgumentIndex, arguments.length));
-      push(forest.createArguments(beginToken.offset, positional, named: named));
+      List<Expression> positional;
+      List<NamedExpression> named;
+      if (libraryBuilder.enableNamedArgumentsAnywhereInLibrary) {
+        positional =
+            new List<Expression>.filled(positionalCount, dummyExpression);
+        named = new List<NamedExpression>.filled(
+            arguments.length - positionalCount, dummyNamedExpression);
+        int positionalIndex = 0;
+        int namedIndex = 0;
+        for (int i = 0; i < arguments.length; i++) {
+          if (arguments[i] is NamedExpression) {
+            named[namedIndex++] = arguments[i] as NamedExpression;
+          } else {
+            positional[positionalIndex++] = arguments[i] as Expression;
+          }
+        }
+        assert(
+            positionalIndex == positional.length && namedIndex == named.length);
+      } else {
+        positional = new List<Expression>.from(
+            arguments.getRange(0, firstNamedArgumentIndex));
+        named = new List<NamedExpression>.from(
+            arguments.getRange(firstNamedArgumentIndex, arguments.length));
+      }
+
+      push(forest.createArguments(beginToken.offset, positional,
+          named: named, argumentsOriginalOrder: argumentsOriginalOrder));
     } else {
       // TODO(kmillikin): Find a way to avoid allocating a second list in the
       // case where there were no named arguments, which is a common one.
       push(forest.createArguments(
-          beginToken.offset, new List<Expression>.from(arguments)));
+          beginToken.offset, new List<Expression>.from(arguments),
+          argumentsOriginalOrder: argumentsOriginalOrder));
     }
     assert(checkState(beginToken, [ValueKinds.Arguments]));
   }
@@ -1831,7 +1873,7 @@
     } else if (arguments == null) {
       push(receiver);
     } else {
-      push(finishSend(receiver, typeArguments, arguments as Arguments,
+      push(finishSend(receiver, typeArguments, arguments as ArgumentsImpl,
           beginToken.charOffset,
           isTypeArgumentsInForest: isInForest));
     }
@@ -1847,8 +1889,11 @@
   }
 
   @override
-  Expression_Generator_Initializer finishSend(Object receiver,
-      List<UnresolvedType>? typeArguments, Arguments arguments, int charOffset,
+  Expression_Generator_Initializer finishSend(
+      Object receiver,
+      List<UnresolvedType>? typeArguments,
+      ArgumentsImpl arguments,
+      int charOffset,
       {bool isTypeArgumentsInForest = false}) {
     if (receiver is Generator) {
       return receiver.doInvocation(charOffset, typeArguments, arguments,

diff --git a/pkg/front_end/lib/src/fasta/kernel/expression_generator.dart b/pkg/front_end/lib/src/fasta/kernel/expression_generator.dart
index 04979e2..cd04351 100644
--- a/pkg/front_end/lib/src/fasta/kernel/expression_generator.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/expression_generator.dart

@@ -217,7 +217,7 @@
   /// If the invocation has explicit type arguments
   /// [buildTypeWithResolvedArguments] called instead.
   Expression_Generator_Initializer doInvocation(
-      int offset, List<UnresolvedType>? typeArguments, Arguments arguments,
+      int offset, List<UnresolvedType>? typeArguments, ArgumentsImpl arguments,
       {bool isTypeArgumentsInForest = false});
 
   Expression_Generator buildSelectorAccess(
@@ -1774,7 +1774,7 @@
 
   @override
   Expression doInvocation(
-      int offset, List<UnresolvedType>? typeArguments, Arguments arguments,
+      int offset, List<UnresolvedType>? typeArguments, ArgumentsImpl arguments,
       {bool isTypeArgumentsInForest = false}) {
     if (invokeTarget != null) {
       return _helper.buildExtensionMethodInvocation(
@@ -1789,7 +1789,8 @@
               extensionTypeArguments: _createExtensionTypeArguments(),
               typeArguments: arguments.types,
               positionalArguments: arguments.positional,
-              namedArguments: arguments.named),
+              namedArguments: arguments.named,
+              argumentsOriginalOrder: arguments.argumentsOriginalOrder),
           isTearOff: false);
     } else {
       return _helper.forest.createExpressionInvocation(
@@ -2649,8 +2650,8 @@
     Generator generator =
         _createInstanceAccess(send.token, send.name, isNullAware: isNullAware);
     if (send.arguments != null) {
-      return generator.doInvocation(
-          offsetForToken(send.token), send.typeArguments, send.arguments!,
+      return generator.doInvocation(offsetForToken(send.token),
+          send.typeArguments, send.arguments! as ArgumentsImpl,
           isTypeArgumentsInForest: send.isTypeArgumentsInForest);
     } else {
       return generator;
@@ -2676,7 +2677,7 @@
 
   @override
   Expression_Generator_Initializer doInvocation(
-      int offset, List<UnresolvedType>? typeArguments, Arguments arguments,
+      int offset, List<UnresolvedType>? typeArguments, ArgumentsImpl arguments,
       {bool isTypeArgumentsInForest = false}) {
     Generator generator = _createInstanceAccess(token, callName);
     return generator.doInvocation(offset, typeArguments, arguments,
@@ -2935,7 +2936,7 @@
 
   @override
   Expression_Generator_Initializer doInvocation(
-      int offset, List<UnresolvedType>? typeArguments, Arguments arguments,
+      int offset, List<UnresolvedType>? typeArguments, ArgumentsImpl arguments,
       {bool isTypeArgumentsInForest = false}) {
     Object suffix = suffixGenerator.doInvocation(
         offset, typeArguments, arguments,
@@ -3126,7 +3127,7 @@
       Selector send, int operatorOffset, bool isNullAware) {
     int nameOffset = offsetForToken(send.token);
     Name name = send.name;
-    Arguments? arguments = send.arguments;
+    ArgumentsImpl? arguments = send.arguments as ArgumentsImpl?;
 
     TypeDeclarationBuilder? declarationBuilder = declaration;
     TypeAliasBuilder? aliasBuilder;
@@ -4067,8 +4068,8 @@
         "'${send.name.text}' != ${send.token.lexeme}");
     Object result = qualifiedLookup(send.token);
     if (send is InvocationSelector) {
-      result = _helper.finishSend(
-          result, send.typeArguments, send.arguments, send.fileOffset,
+      result = _helper.finishSend(result, send.typeArguments,
+          send.arguments as ArgumentsImpl, send.fileOffset,
           isTypeArgumentsInForest: send.isTypeArgumentsInForest);
     }
     if (isNullAware) {

diff --git a/pkg/front_end/lib/src/fasta/kernel/expression_generator_helper.dart b/pkg/front_end/lib/src/fasta/kernel/expression_generator_helper.dart
index 96e8b7f..9f355e5 100644
--- a/pkg/front_end/lib/src/fasta/kernel/expression_generator_helper.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/expression_generator_helper.dart

@@ -54,12 +54,14 @@
 
   bool get enableConstructorTearOffsInLibrary;
 
+  bool get enableNamedArgumentsAnywhereInLibrary;
+
   Expression_Generator_Builder scopeLookup(
       Scope scope, String name, Token token,
       {bool isQualified: false, PrefixBuilder? prefix});
 
   Expression_Generator_Initializer finishSend(Object receiver,
-      List<UnresolvedType>? typeArguments, Arguments arguments, int offset,
+      List<UnresolvedType>? typeArguments, ArgumentsImpl arguments, int offset,
       {bool isTypeArgumentsInForest = false});
 
   Initializer buildInvalidInitializer(Expression expression,

diff --git a/pkg/front_end/lib/src/fasta/kernel/forest.dart b/pkg/front_end/lib/src/fasta/kernel/forest.dart
index 4cc99a7..8e7b3b9 100644
--- a/pkg/front_end/lib/src/fasta/kernel/forest.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/forest.dart

@@ -27,19 +27,25 @@
 class Forest {
   const Forest();
 
-  Arguments createArguments(int fileOffset, List<Expression> positional,
+  ArgumentsImpl createArguments(int fileOffset, List<Expression> positional,
       {List<DartType>? types,
       List<NamedExpression>? named,
-      bool hasExplicitTypeArguments = true}) {
+      bool hasExplicitTypeArguments = true,
+      List<Object?>? argumentsOriginalOrder}) {
     // ignore: unnecessary_null_comparison
     assert(fileOffset != null);
     if (!hasExplicitTypeArguments) {
-      ArgumentsImpl arguments =
-          new ArgumentsImpl(positional, types: <DartType>[], named: named);
+      ArgumentsImpl arguments = new ArgumentsImpl(positional,
+          types: <DartType>[],
+          named: named,
+          argumentsOriginalOrder: argumentsOriginalOrder);
       arguments.types.addAll(types!);
       return arguments;
     } else {
-      return new ArgumentsImpl(positional, types: types, named: named)
+      return new ArgumentsImpl(positional,
+          types: types,
+          named: named,
+          argumentsOriginalOrder: argumentsOriginalOrder)
         ..fileOffset = fileOffset;
     }
   }
@@ -53,7 +59,8 @@
       int? extensionTypeArgumentOffset,
       List<DartType> typeArguments = const <DartType>[],
       List<Expression> positionalArguments = const <Expression>[],
-      List<NamedExpression> namedArguments = const <NamedExpression>[]}) {
+      List<NamedExpression> namedArguments = const <NamedExpression>[],
+      List<Object?>? argumentsOriginalOrder}) {
     // ignore: unnecessary_null_comparison
     assert(fileOffset != null);
     return new ArgumentsImpl.forExtensionMethod(
@@ -62,11 +69,12 @@
         extensionTypeArgumentOffset: extensionTypeArgumentOffset,
         typeArguments: typeArguments,
         positionalArguments: positionalArguments,
-        namedArguments: namedArguments)
+        namedArguments: namedArguments,
+        argumentsOriginalOrder: argumentsOriginalOrder)
       ..fileOffset = fileOffset;
   }
 
-  Arguments createArgumentsEmpty(int fileOffset) {
+  ArgumentsImpl createArgumentsEmpty(int fileOffset) {
     // ignore: unnecessary_null_comparison
     assert(fileOffset != null);
     return createArguments(fileOffset, <Expression>[]);

diff --git a/pkg/front_end/lib/src/fasta/kernel/inference_visitor.dart b/pkg/front_end/lib/src/fasta/kernel/inference_visitor.dart
index 9956d82..ac7b321 100644
--- a/pkg/front_end/lib/src/fasta/kernel/inference_visitor.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/inference_visitor.dart

@@ -640,8 +640,8 @@
     bool hadExplicitTypeArguments = hasExplicitTypeArguments(node.arguments);
     FunctionType functionType = node.target.function
         .computeThisFunctionType(inferrer.library.nonNullable);
-    InvocationInferenceResult result = inferrer.inferInvocation(
-        typeContext, node.fileOffset, functionType, node.arguments,
+    InvocationInferenceResult result = inferrer.inferInvocation(typeContext,
+        node.fileOffset, functionType, node.arguments as ArgumentsImpl,
         isConst: node.isConst, staticTarget: node.target);
     if (!inferrer.isTopLevel) {
       SourceLibraryBuilder library = inferrer.library;
@@ -670,8 +670,8 @@
         : new FunctionType(
             [], const DynamicType(), inferrer.library.nonNullable);
     TypeArgumentsInfo typeArgumentsInfo = getTypeArgumentsInfo(node.arguments);
-    InvocationInferenceResult result = inferrer.inferInvocation(
-        typeContext, node.fileOffset, calleeType, node.arguments,
+    InvocationInferenceResult result = inferrer.inferInvocation(typeContext,
+        node.fileOffset, calleeType, node.arguments as ArgumentsImpl,
         staticTarget: node.target);
     StaticInvocation replacement =
         new StaticInvocation(node.target, node.arguments);
@@ -932,8 +932,8 @@
     FunctionType functionType = node.target.function
         .computeThisFunctionType(inferrer.library.nonNullable);
 
-    InvocationInferenceResult result = inferrer.inferInvocation(
-        typeContext, node.fileOffset, functionType, node.arguments,
+    InvocationInferenceResult result = inferrer.inferInvocation(typeContext,
+        node.fileOffset, functionType, node.arguments as ArgumentsImpl,
         isConst: node.isConst, staticTarget: node.target);
     node.hasBeenInferred = true;
     Expression resultNode = node;
@@ -963,8 +963,8 @@
         .computeAliasedConstructorFunctionType(
             typedef, inferrer.library.library);
     calleeType = replaceReturnType(calleeType, calleeType.returnType.unalias);
-    InvocationInferenceResult result = inferrer.inferInvocation(
-        typeContext, node.fileOffset, calleeType, node.arguments,
+    InvocationInferenceResult result = inferrer.inferInvocation(typeContext,
+        node.fileOffset, calleeType, node.arguments as ArgumentsImpl,
         isConst: node.isConst, staticTarget: node.target);
     node.hasBeenInferred = true;
     Expression resultNode = node;
@@ -987,8 +987,8 @@
     FunctionType calleeType = node.target.function
         .computeAliasedFactoryFunctionType(typedef, inferrer.library.library);
     calleeType = replaceReturnType(calleeType, calleeType.returnType.unalias);
-    InvocationInferenceResult result = inferrer.inferInvocation(
-        typeContext, node.fileOffset, calleeType, node.arguments,
+    InvocationInferenceResult result = inferrer.inferInvocation(typeContext,
+        node.fileOffset, calleeType, node.arguments as ArgumentsImpl,
         isConst: node.isConst, staticTarget: node.target);
     node.hasBeenInferred = true;
     Expression resultNode = node;
@@ -2827,9 +2827,16 @@
     Link<NullAwareGuard> nullAwareGuards = result.nullAwareGuards;
     Expression receiver = result.nullAwareAction;
     DartType receiverType = result.nullAwareActionType;
-    return inferrer.inferMethodInvocation(node.fileOffset, nullAwareGuards,
-        receiver, receiverType, node.name, node.arguments, typeContext,
-        isExpressionInvocation: false, isImplicitCall: false);
+    return inferrer.inferMethodInvocation(
+        node.fileOffset,
+        nullAwareGuards,
+        receiver,
+        receiverType,
+        node.name,
+        node.arguments as ArgumentsImpl,
+        typeContext,
+        isExpressionInvocation: false,
+        isImplicitCall: false);
   }
 
   ExpressionInferenceResult visitExpressionInvocation(
@@ -2839,9 +2846,16 @@
     Link<NullAwareGuard> nullAwareGuards = result.nullAwareGuards;
     Expression receiver = result.nullAwareAction;
     DartType receiverType = result.nullAwareActionType;
-    return inferrer.inferMethodInvocation(node.fileOffset, nullAwareGuards,
-        receiver, receiverType, callName, node.arguments, typeContext,
-        isExpressionInvocation: true, isImplicitCall: true);
+    return inferrer.inferMethodInvocation(
+        node.fileOffset,
+        nullAwareGuards,
+        receiver,
+        receiverType,
+        callName,
+        node.arguments as ArgumentsImpl,
+        typeContext,
+        isExpressionInvocation: true,
+        isImplicitCall: true);
   }
 
   ExpressionInferenceResult visitNamedFunctionExpressionJudgment(
@@ -5798,8 +5812,8 @@
             .computeThisFunctionType(inferrer.library.nonNullable),
         inferrer.coreTypes.thisInterfaceType(
             node.target.enclosingClass, inferrer.library.nonNullable));
-    inferrer.inferInvocation(
-        const UnknownType(), node.fileOffset, functionType, node.arguments,
+    inferrer.inferInvocation(const UnknownType(), node.fileOffset, functionType,
+        node.arguments as ArgumentsImpl,
         skipTypeArgumentInference: true, staticTarget: node.target);
     ArgumentsImpl.removeNonInferrableArgumentTypes(
         node.arguments as ArgumentsImpl);
@@ -5974,8 +5988,8 @@
         : new FunctionType(
             [], const DynamicType(), inferrer.library.nonNullable);
     TypeArgumentsInfo typeArgumentsInfo = getTypeArgumentsInfo(node.arguments);
-    InvocationInferenceResult result = inferrer.inferInvocation(
-        typeContext, node.fileOffset, calleeType, node.arguments,
+    InvocationInferenceResult result = inferrer.inferInvocation(typeContext,
+        node.fileOffset, calleeType, node.arguments as ArgumentsImpl,
         staticTarget: node.target);
     // ignore: unnecessary_null_comparison
     if (!inferrer.isTopLevel && node.target != null) {
@@ -6022,8 +6036,8 @@
             .computeThisFunctionType(inferrer.library.nonNullable)
             .withoutTypeParameters) as FunctionType,
         inferrer.thisType!);
-    inferrer.inferInvocation(
-        const UnknownType(), node.fileOffset, functionType, node.arguments,
+    inferrer.inferInvocation(const UnknownType(), node.fileOffset, functionType,
+        node.arguments as ArgumentsImpl,
         skipTypeArgumentInference: true, staticTarget: node.target);
   }
 
@@ -6770,8 +6784,8 @@
     if (node.arguments != null) {
       FunctionType calleeType =
           new FunctionType([], inferredType, inferrer.library.nonNullable);
-      inferrer.inferInvocation(
-          typeContext, node.fileOffset, calleeType, node.arguments!);
+      inferrer.inferInvocation(typeContext, node.fileOffset, calleeType,
+          node.arguments! as ArgumentsImpl);
     }
     return new ExpressionInferenceResult(inferredType, node);
   }

diff --git a/pkg/front_end/lib/src/fasta/kernel/internal_ast.dart b/pkg/front_end/lib/src/fasta/kernel/internal_ast.dart
index b587d91..7560883 100644
--- a/pkg/front_end/lib/src/fasta/kernel/internal_ast.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/internal_ast.dart

@@ -491,6 +491,8 @@
 
   int _explicitTypeArgumentCount;
 
+  List<Object?>? argumentsOriginalOrder;
+
   ArgumentsImpl.internal(
       {required List<Expression> positional,
       required List<DartType>? types,
@@ -504,10 +506,13 @@
             explicitExtensionTypeArgumentCount,
         this._extensionTypeArgumentOffset = extensionTypeArgumentOffset,
         this._explicitTypeArgumentCount = explicitTypeArgumentCount,
+        this.argumentsOriginalOrder = null,
         super(positional, types: types, named: named);
 
   ArgumentsImpl(List<Expression> positional,
-      {List<DartType>? types, List<NamedExpression>? named})
+      {List<DartType>? types,
+      List<NamedExpression>? named,
+      this.argumentsOriginalOrder})
       : _explicitTypeArgumentCount = types?.length ?? 0,
         _extensionTypeParameterCount = 0,
         _explicitExtensionTypeArgumentCount = 0,
@@ -521,7 +526,8 @@
       int? extensionTypeArgumentOffset,
       List<DartType> typeArguments = const <DartType>[],
       List<Expression> positionalArguments = const <Expression>[],
-      List<NamedExpression> namedArguments = const <NamedExpression>[]})
+      List<NamedExpression> namedArguments = const <NamedExpression>[],
+      this.argumentsOriginalOrder})
       : _extensionTypeParameterCount = extensionTypeParameterCount,
         _explicitExtensionTypeArgumentCount = extensionTypeArguments.length,
         _explicitTypeArgumentCount = typeArguments.length,

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 dbecaaa..9c6d6bb 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

@@ -318,6 +318,7 @@
   bool? _enableGenericMetadataInLibrary;
   bool? _enableExtensionTypesInLibrary;
   bool? _enableConstructorTearOffsInLibrary;
+  bool? _enableNamedArgumentsAnywhereInLibrary;
 
   bool get enableConstFunctionsInLibrary => _enableConstFunctionsInLibrary ??=
       loader.target.isExperimentEnabledInLibraryByVersion(
@@ -392,6 +393,10 @@
           .getExperimentEnabledVersionInLibrary(
               ExperimentalFlag.extensionTypes, _packageUri ?? importUri);
 
+  bool get enableNamedArgumentsAnywhereInLibrary =>
+      _enableNamedArgumentsAnywhereInLibrary ??=
+          loader.enableUnscheduledExperiments;
+
   void _updateLibraryNNBDSettings() {
     library.isNonNullableByDefault = isNonNullableByDefault;
     switch (loader.nnbdMode) {

diff --git a/pkg/front_end/lib/src/fasta/source/source_loader.dart b/pkg/front_end/lib/src/fasta/source/source_loader.dart
index 9e34d6d..29e57b3 100644
--- a/pkg/front_end/lib/src/fasta/source/source_loader.dart
+++ b/pkg/front_end/lib/src/fasta/source/source_loader.dart

@@ -503,6 +503,9 @@
 
   NnbdMode get nnbdMode => target.context.options.nnbdMode;
 
+  bool get enableUnscheduledExperiments =>
+      target.context.options.enableUnscheduledExperiments;
+
   CoreTypes get coreTypes {
     assert(_coreTypes != null, "CoreTypes has not been computed.");
     return _coreTypes!;

diff --git a/pkg/front_end/lib/src/fasta/type_inference/type_inferrer.dart b/pkg/front_end/lib/src/fasta/type_inference/type_inferrer.dart
index cf74dd7..888eeaf 100644
--- a/pkg/front_end/lib/src/fasta/type_inference/type_inferrer.dart
+++ b/pkg/front_end/lib/src/fasta/type_inference/type_inferrer.dart

@@ -2085,7 +2085,7 @@
   }
 
   InvocationInferenceResult inferInvocation(DartType typeContext, int offset,
-      FunctionType calleeType, Arguments arguments,
+      FunctionType calleeType, ArgumentsImpl arguments,
       {List<VariableDeclaration>? hoistedExpressions,
       bool isSpecialCasedBinaryOperator: false,
       bool isSpecialCasedTernaryOperator: false,
@@ -2143,7 +2143,7 @@
         typeParameters: calleeType.typeParameters
             .take(extensionTypeParameterCount)
             .toList());
-    Arguments extensionArguments = engine.forest.createArguments(
+    ArgumentsImpl extensionArguments = engine.forest.createArguments(
         arguments.fileOffset, [arguments.positional.first],
         types: getExplicitExtensionTypeArguments(arguments));
     _inferInvocation(const UnknownType(), offset, extensionFunctionType,
@@ -2171,7 +2171,7 @@
         typeParameters: targetTypeParameters);
     targetFunctionType = extensionSubstitution
         .substituteType(targetFunctionType) as FunctionType;
-    Arguments targetArguments = engine.forest.createArguments(
+    ArgumentsImpl targetArguments = engine.forest.createArguments(
         arguments.fileOffset, arguments.positional.skip(1).toList(),
         named: arguments.named, types: getExplicitTypeArguments(arguments));
     InvocationInferenceResult result = _inferInvocation(typeContext, offset,
@@ -2201,7 +2201,7 @@
       DartType typeContext,
       int offset,
       FunctionType calleeType,
-      Arguments arguments,
+      ArgumentsImpl arguments,
       List<VariableDeclaration>? hoistedExpressions,
       {bool isSpecialCasedBinaryOperator: false,
       bool isSpecialCasedTernaryOperator: false,
@@ -2215,6 +2215,7 @@
     // [receiverType] must be provided for special-cased operators.
     assert(!isSpecialCasedBinaryOperator && !isSpecialCasedTernaryOperator ||
         receiverType != null);
+
     List<TypeParameter> calleeTypeParameters = calleeType.typeParameters;
     if (calleeTypeParameters.isNotEmpty) {
       // It's possible that one of the callee type parameters might match a type
@@ -2230,11 +2231,14 @@
       calleeType = fresh.applyToFunctionType(calleeType);
       calleeTypeParameters = fresh.freshTypeParameters;
     }
+
     List<DartType>? explicitTypeArguments = getExplicitTypeArguments(arguments);
+
     bool inferenceNeeded = !skipTypeArgumentInference &&
         explicitTypeArguments == null &&
         calleeTypeParameters.isNotEmpty;
     bool typeChecksNeeded = !isTopLevel;
+
     List<DartType>? inferredTypes;
     Substitution? substitution;
     List<DartType>? formalTypes;
@@ -2243,6 +2247,15 @@
       formalTypes = [];
       actualTypes = [];
     }
+
+    List<VariableDeclaration>? localHoistedExpressions;
+    if (library.enableNamedArgumentsAnywhereInLibrary &&
+        arguments.argumentsOriginalOrder != null &&
+        hoistedExpressions == null &&
+        !isTopLevel) {
+      hoistedExpressions = localHoistedExpressions = <VariableDeclaration>[];
+    }
+
     if (inferenceNeeded) {
       // ignore: unnecessary_null_comparison
       if (isConst && typeContext != null) {
@@ -2281,60 +2294,166 @@
         staticTarget == typeSchemaEnvironment.coreTypes.identicalProcedure;
     // TODO(paulberry): if we are doing top level inference and type arguments
     // were omitted, report an error.
-    for (int position = 0; position < arguments.positional.length; position++) {
-      DartType formalType = getPositionalParameterType(calleeType, position);
-      DartType inferredFormalType = substitution != null
-          ? substitution.substituteType(formalType)
-          : formalType;
-      DartType inferredType;
-      if (isImplicitExtensionMember && position == 0) {
-        assert(
-            receiverType != null,
-            "No receiver type provided for implicit extension member "
-            "invocation.");
-        continue;
+    List<Object?> argumentsEvaluationOrder;
+    if (library.enableNamedArgumentsAnywhereInLibrary &&
+        arguments.argumentsOriginalOrder != null) {
+      if (staticTarget?.isExtensionMember ?? false) {
+        // Add the receiver.
+        argumentsEvaluationOrder = <Object?>[
+          arguments.positional[0],
+          ...arguments.argumentsOriginalOrder!
+        ];
       } else {
-        if (isSpecialCasedBinaryOperator) {
-          inferredFormalType =
-              typeSchemaEnvironment.getContextTypeOfSpecialCasedBinaryOperator(
-                  typeContext, receiverType!, inferredFormalType,
-                  isNonNullableByDefault: isNonNullableByDefault);
-        } else if (isSpecialCasedTernaryOperator) {
-          inferredFormalType =
-              typeSchemaEnvironment.getContextTypeOfSpecialCasedTernaryOperator(
-                  typeContext, receiverType!, inferredFormalType,
-                  isNonNullableByDefault: isNonNullableByDefault);
+        argumentsEvaluationOrder = arguments.argumentsOriginalOrder!;
+      }
+    } else {
+      argumentsEvaluationOrder = <Object?>[
+        ...arguments.positional,
+        ...arguments.named
+      ];
+    }
+    arguments.argumentsOriginalOrder = null;
+
+    // The following loop determines how many argument expressions should be
+    // hoisted to preserve the evaluation order. The computation is based on the
+    // following observation: the largest suffix of the argument vector, such
+    // that every positional argument in that suffix comes before any named
+    // argument, retains the evaluation order after the rest of the arguments
+    // are hoisted, and therefore doesn't need to be hoisted itself. The loop
+    // below finds the starting position of such suffix and stores it in the
+    // [hoistingEndIndex] variable. In case all positional arguments come
+    // before all named arguments, the suffix coincides with the entire argument
+    // vector, and none of the arguments is hoisted. That way the legacy
+    // behavior is preserved.
+    int hoistingEndIndex;
+    if (library.enableNamedArgumentsAnywhereInLibrary) {
+      hoistingEndIndex = argumentsEvaluationOrder.length - 1;
+      for (int i = argumentsEvaluationOrder.length - 2;
+          i >= 0 && hoistingEndIndex == i + 1;
+          i--) {
+        int previousWeight =
+            argumentsEvaluationOrder[i + 1] is NamedExpression ? 1 : 0;
+        int currentWeight =
+            argumentsEvaluationOrder[i] is NamedExpression ? 1 : 0;
+        if (currentWeight <= previousWeight) {
+          --hoistingEndIndex;
         }
+      }
+    } else {
+      hoistingEndIndex = 0;
+    }
+
+    int positionalIndex = 0;
+    int namedIndex = 0;
+    for (int evaluationOrderIndex = 0;
+        evaluationOrderIndex < argumentsEvaluationOrder.length;
+        evaluationOrderIndex++) {
+      Object? argument = argumentsEvaluationOrder[evaluationOrderIndex];
+      assert(
+          argument is Expression || argument is NamedExpression,
+          "Expected the argument to be either an Expression "
+          "or a NamedExpression, got '${argument.runtimeType}'.");
+      if (argument is Expression) {
+        int index = positionalIndex++;
+        DartType formalType = getPositionalParameterType(calleeType, index);
+        DartType inferredFormalType = substitution != null
+            ? substitution.substituteType(formalType)
+            : formalType;
+        DartType inferredType;
+        if (isImplicitExtensionMember && index == 0) {
+          assert(
+              receiverType != null,
+              "No receiver type provided for implicit extension member "
+              "invocation.");
+          continue;
+        } else {
+          if (isSpecialCasedBinaryOperator) {
+            inferredFormalType = typeSchemaEnvironment
+                .getContextTypeOfSpecialCasedBinaryOperator(
+                    typeContext, receiverType!, inferredFormalType,
+                    isNonNullableByDefault: isNonNullableByDefault);
+          } else if (isSpecialCasedTernaryOperator) {
+            inferredFormalType = typeSchemaEnvironment
+                .getContextTypeOfSpecialCasedTernaryOperator(
+                    typeContext, receiverType!, inferredFormalType,
+                    isNonNullableByDefault: isNonNullableByDefault);
+          }
+          ExpressionInferenceResult result = inferExpression(
+              arguments.positional[index],
+              isNonNullableByDefault
+                  ? inferredFormalType
+                  : legacyErasure(inferredFormalType),
+              inferenceNeeded ||
+                  isSpecialCasedBinaryOperator ||
+                  isSpecialCasedTernaryOperator ||
+                  typeChecksNeeded);
+          inferredType = identical(result.inferredType, noInferredType) ||
+                  isNonNullableByDefault
+              ? result.inferredType
+              : legacyErasure(result.inferredType);
+          if (localHoistedExpressions != null &&
+              evaluationOrderIndex >= hoistingEndIndex) {
+            hoistedExpressions = null;
+          }
+          Expression expression =
+              _hoist(result.expression, inferredType, hoistedExpressions);
+          if (isIdentical && arguments.positional.length == 2) {
+            if (index == 0) {
+              flowAnalysis.equalityOp_rightBegin(expression, inferredType);
+            } else {
+              flowAnalysis.equalityOp_end(
+                  arguments.parent as Expression, expression, inferredType);
+            }
+          }
+          arguments.positional[index] = expression..parent = arguments;
+        }
+        if (inferenceNeeded || typeChecksNeeded) {
+          formalTypes!.add(formalType);
+          actualTypes!.add(inferredType);
+        }
+      } else {
+        assert(argument is NamedExpression);
+        int index = namedIndex++;
+        NamedExpression namedArgument = arguments.named[index];
+        DartType formalType =
+            getNamedParameterType(calleeType, namedArgument.name);
+        DartType inferredFormalType = substitution != null
+            ? substitution.substituteType(formalType)
+            : formalType;
         ExpressionInferenceResult result = inferExpression(
-            arguments.positional[position],
+            namedArgument.value,
             isNonNullableByDefault
                 ? inferredFormalType
                 : legacyErasure(inferredFormalType),
             inferenceNeeded ||
                 isSpecialCasedBinaryOperator ||
-                isSpecialCasedTernaryOperator ||
                 typeChecksNeeded);
-        inferredType = identical(result.inferredType, noInferredType) ||
-                isNonNullableByDefault
-            ? result.inferredType
-            : legacyErasure(result.inferredType);
+        DartType inferredType =
+            identical(result.inferredType, noInferredType) ||
+                    isNonNullableByDefault
+                ? result.inferredType
+                : legacyErasure(result.inferredType);
+        if (localHoistedExpressions != null &&
+            evaluationOrderIndex >= hoistingEndIndex) {
+          hoistedExpressions = null;
+        }
         Expression expression =
             _hoist(result.expression, inferredType, hoistedExpressions);
-        if (isIdentical && arguments.positional.length == 2) {
-          if (position == 0) {
-            flowAnalysis.equalityOp_rightBegin(expression, inferredType);
-          } else {
-            flowAnalysis.equalityOp_end(
-                arguments.parent as Expression, expression, inferredType);
-          }
+        namedArgument.value = expression..parent = namedArgument;
+        if (inferenceNeeded || typeChecksNeeded) {
+          formalTypes!.add(formalType);
+          actualTypes!.add(inferredType);
         }
-        arguments.positional[position] = expression..parent = arguments;
-      }
-      if (inferenceNeeded || typeChecksNeeded) {
-        formalTypes!.add(formalType);
-        actualTypes!.add(inferredType);
       }
     }
+    assert(
+        positionalIndex == arguments.positional.length,
+        "Expected 'positionalIndex' to be ${arguments.positional.length}, "
+        "got ${positionalIndex}.");
+    assert(
+        namedIndex == arguments.named.length,
+        "Expected 'namedIndex' to be ${arguments.named.length}, "
+        "got ${namedIndex}.");
     if (isSpecialCasedBinaryOperator) {
       calleeType = replaceReturnType(
           calleeType,
@@ -2347,30 +2466,6 @@
           typeSchemaEnvironment.getTypeOfSpecialCasedTernaryOperator(
               receiverType!, actualTypes![0], actualTypes[1], library.library));
     }
-    for (NamedExpression namedArgument in arguments.named) {
-      DartType formalType =
-          getNamedParameterType(calleeType, namedArgument.name);
-      DartType inferredFormalType = substitution != null
-          ? substitution.substituteType(formalType)
-          : formalType;
-      ExpressionInferenceResult result = inferExpression(
-          namedArgument.value,
-          isNonNullableByDefault
-              ? inferredFormalType
-              : legacyErasure(inferredFormalType),
-          inferenceNeeded || isSpecialCasedBinaryOperator || typeChecksNeeded);
-      DartType inferredType = identical(result.inferredType, noInferredType) ||
-              isNonNullableByDefault
-          ? result.inferredType
-          : legacyErasure(result.inferredType);
-      Expression expression =
-          _hoist(result.expression, inferredType, hoistedExpressions);
-      namedArgument.value = expression..parent = namedArgument;
-      if (inferenceNeeded || typeChecksNeeded) {
-        formalTypes!.add(formalType);
-        actualTypes!.add(inferredType);
-      }
-    }
 
     // Check for and remove duplicated named arguments.
     List<NamedExpression> named = arguments.named;
@@ -2516,7 +2611,9 @@
       calleeType = legacyErasure(calleeType) as FunctionType;
     }
 
-    return new SuccessfulInferenceResult(inferredType, calleeType);
+    return new SuccessfulInferenceResult(inferredType, calleeType,
+        hoistedArguments: localHoistedExpressions,
+        inferredReceiverType: receiverType);
   }
 
   FunctionType inferLocalFunction(FunctionNode function, DartType? typeContext,
@@ -2767,7 +2864,7 @@
       Link<NullAwareGuard> nullAwareGuards,
       Expression receiver,
       Name name,
-      Arguments arguments,
+      ArgumentsImpl arguments,
       DartType typeContext,
       List<VariableDeclaration>? hoistedExpressions,
       {required bool isImplicitCall}) {
@@ -2792,7 +2889,7 @@
       Expression receiver,
       NeverType receiverType,
       Name name,
-      Arguments arguments,
+      ArgumentsImpl arguments,
       DartType typeContext,
       List<VariableDeclaration>? hoistedExpressions,
       {required bool isImplicitCall}) {
@@ -2820,7 +2917,7 @@
       DartType receiverType,
       ObjectAccessTarget target,
       Name name,
-      Arguments arguments,
+      ArgumentsImpl arguments,
       DartType typeContext,
       List<VariableDeclaration>? hoistedExpressions,
       {required bool isExpressionInvocation,
@@ -2854,7 +2951,7 @@
       DartType receiverType,
       ObjectAccessTarget target,
       Name name,
-      Arguments arguments,
+      ArgumentsImpl arguments,
       DartType typeContext,
       List<VariableDeclaration>? hoistedExpressions,
       {required bool isImplicitCall}) {
@@ -2905,8 +3002,8 @@
     } else {
       StaticInvocation staticInvocation = transformExtensionMethodInvocation(
           fileOffset, target, receiver, arguments);
-      InvocationInferenceResult result = inferInvocation(
-          typeContext, fileOffset, functionType, staticInvocation.arguments,
+      InvocationInferenceResult result = inferInvocation(typeContext,
+          fileOffset, functionType, staticInvocation.arguments as ArgumentsImpl,
           hoistedExpressions: hoistedExpressions,
           receiverType: receiverType,
           isImplicitExtensionMember: true,
@@ -2969,7 +3066,7 @@
       Expression receiver,
       DartType receiverType,
       ObjectAccessTarget target,
-      Arguments arguments,
+      ArgumentsImpl arguments,
       DartType typeContext,
       List<VariableDeclaration>? hoistedExpressions,
       {required bool isImplicitCall}) {
@@ -3122,8 +3219,8 @@
             method.enclosingClass!, method.function.returnType)) {
       contravariantCheck = true;
     }
-    InvocationInferenceResult result = inferInvocation(
-        typeContext, fileOffset, declaredFunctionType, arguments,
+    InvocationInferenceResult result = inferInvocation(typeContext, fileOffset,
+        declaredFunctionType, arguments as ArgumentsImpl,
         hoistedExpressions: hoistedExpressions,
         receiverType: receiverType,
         isImplicitCall: isImplicitCall,
@@ -3238,7 +3335,7 @@
       Expression receiver,
       DartType receiverType,
       ObjectAccessTarget target,
-      Arguments arguments,
+      ArgumentsImpl arguments,
       DartType typeContext,
       List<VariableDeclaration>? hoistedExpressions,
       {required bool isExpressionInvocation}) {
@@ -3445,7 +3542,7 @@
       Expression receiver,
       DartType receiverType,
       ObjectAccessTarget target,
-      Arguments arguments,
+      ArgumentsImpl arguments,
       DartType typeContext,
       List<VariableDeclaration>? hoistedExpressions,
       {required bool isExpressionInvocation}) {
@@ -3619,7 +3716,7 @@
       Expression receiver,
       DartType receiverType,
       Name name,
-      Arguments arguments,
+      ArgumentsImpl arguments,
       DartType typeContext,
       {required bool isExpressionInvocation,
       required bool isImplicitCall,
@@ -3842,7 +3939,7 @@
         : const ObjectAccessTarget.missing();
     int fileOffset = expression.fileOffset;
     Name methodName = expression.name;
-    Arguments arguments = expression.arguments;
+    ArgumentsImpl arguments = expression.arguments as ArgumentsImpl;
     DartType receiverType = thisType!;
     bool isSpecialCasedBinaryOperator =
         isSpecialCasedBinaryOperatorForReceiverType(target, receiverType);
@@ -4772,10 +4869,65 @@
   @override
   final FunctionType functionType;
 
-  SuccessfulInferenceResult(this.inferredType, this.functionType);
+  final List<VariableDeclaration>? hoistedArguments;
+
+  final DartType? inferredReceiverType;
+
+  SuccessfulInferenceResult(this.inferredType, this.functionType,
+      {this.hoistedArguments, this.inferredReceiverType});
 
   @override
-  Expression applyResult(Expression expression) => expression;
+  Expression applyResult(Expression expression) {
+    List<VariableDeclaration>? hoistedArguments = this.hoistedArguments;
+    if (hoistedArguments == null || hoistedArguments.isEmpty) {
+      return expression;
+    } else {
+      assert(expression is InvocationExpression);
+      if (expression is FactoryConstructorInvocation) {
+        return _insertHoistedExpressions(expression, hoistedArguments);
+      } else if (expression is TypeAliasedConstructorInvocation) {
+        // Should be unaliased at this point, the code is for completeness.
+        return _insertHoistedExpressions(expression, hoistedArguments);
+      } else if (expression is TypeAliasedFactoryInvocation) {
+        // Should be unaliased at this point, the code is for completeness.
+        return expression;
+      } else if (expression is ConstructorInvocation) {
+        return _insertHoistedExpressions(expression, hoistedArguments);
+      } else if (expression is DynamicInvocation) {
+        return _insertHoistedExpressions(expression, hoistedArguments);
+      } else if (expression is FunctionInvocation) {
+        return _insertHoistedExpressions(expression, hoistedArguments);
+      } else if (expression is InstanceGetterInvocation) {
+        // The hoisting of InstanceGetterInvocation is performed elsewhere.
+        return expression;
+      } else if (expression is InstanceInvocation) {
+        VariableDeclaration receiver = createVariable(
+            expression.receiver, inferredReceiverType ?? const DynamicType());
+        expression.receiver = createVariableGet(receiver)..parent = expression;
+        return createLet(
+            receiver, _insertHoistedExpressions(expression, hoistedArguments));
+      } else if (expression is LocalFunctionInvocation) {
+        return _insertHoistedExpressions(expression, hoistedArguments);
+      } else if (expression is StaticInvocation) {
+        return _insertHoistedExpressions(expression, hoistedArguments);
+      } else if (expression is SuperMethodInvocation) {
+        return _insertHoistedExpressions(expression, hoistedArguments);
+      } else {
+        throw new StateError(
+            "Unhandled invocation kind '${expression.runtimeType}'.");
+      }
+    }
+  }
+
+  static Expression _insertHoistedExpressions(
+      Expression expression, List<VariableDeclaration> hoistedExpressions) {
+    if (hoistedExpressions.isNotEmpty) {
+      for (int index = hoistedExpressions.length - 1; index >= 0; index--) {
+        expression = createLet(hoistedExpressions[index], expression);
+      }
+    }
+    return expression;
+  }
 
   @override
   bool get isInapplicable => false;

diff --git a/pkg/front_end/test/fasta/testing/suite.dart b/pkg/front_end/test/fasta/testing/suite.dart
index 387f68f..4275910 100644
--- a/pkg/front_end/test/fasta/testing/suite.dart
+++ b/pkg/front_end/test/fasta/testing/suite.dart

@@ -227,6 +227,7 @@
 
 const List<Option> folderOptionsSpecification = [
   Options.enableExperiment,
+  Options.enableUnscheduledExperiments,
   Options.forceLateLoweringSentinel,
   overwriteCurrentSdkVersion,
   Options.forceLateLowering,
@@ -261,6 +262,7 @@
 /// test folders.
 class FolderOptions {
   final Map<ExperimentalFlag, bool> _explicitExperimentalFlags;
+  final bool? enableUnscheduledExperiments;
   final int? forceLateLowerings;
   final bool? forceLateLoweringSentinel;
   final bool? forceStaticFieldLowering;
@@ -273,7 +275,8 @@
   final String? overwriteCurrentSdkVersion;
 
   FolderOptions(this._explicitExperimentalFlags,
-      {this.forceLateLowerings,
+      {this.enableUnscheduledExperiments,
+      this.forceLateLowerings,
       this.forceLateLoweringSentinel,
       this.forceStaticFieldLowering,
       this.forceNoExplicitGetterCalls,
@@ -441,6 +444,7 @@
   FolderOptions _computeFolderOptions(Directory directory) {
     FolderOptions? folderOptions = _folderOptions[directory.uri];
     if (folderOptions == null) {
+      bool? enableUnscheduledExperiments;
       int? forceLateLowering;
       bool? forceLateLoweringSentinel;
       bool? forceStaticFieldLowering;
@@ -452,6 +456,7 @@
       String target = "vm";
       if (directory.uri == baseUri) {
         folderOptions = new FolderOptions({},
+            enableUnscheduledExperiments: enableUnscheduledExperiments,
             forceLateLowerings: forceLateLowering,
             forceLateLoweringSentinel: forceLateLoweringSentinel,
             forceStaticFieldLowering: forceStaticFieldLowering,
@@ -473,6 +478,8 @@
               Options.enableExperiment.read(parsedOptions) ?? <String>[];
           String overwriteCurrentSdkVersionArgument =
               overwriteCurrentSdkVersion.read(parsedOptions);
+          enableUnscheduledExperiments =
+              Options.enableUnscheduledExperiments.read(parsedOptions);
           forceLateLoweringSentinel =
               Options.forceLateLoweringSentinel.read(parsedOptions);
           forceLateLowering = Options.forceLateLowering.read(parsedOptions);
@@ -499,6 +506,7 @@
                   onError: (String message) => throw new ArgumentError(message),
                   onWarning: (String message) =>
                       throw new ArgumentError(message)),
+              enableUnscheduledExperiments: enableUnscheduledExperiments,
               forceLateLowerings: forceLateLowering,
               forceLateLoweringSentinel: forceLateLoweringSentinel,
               forceStaticFieldLowering: forceStaticFieldLowering,
@@ -541,6 +549,8 @@
         }
         ..sdkRoot = sdk
         ..packagesFileUri = uriConfiguration.packageConfigUri ?? packages
+        ..enableUnscheduledExperiments =
+            folderOptions.enableUnscheduledExperiments ?? false
         ..environmentDefines = folderOptions.defines
         ..explicitExperimentalFlags = folderOptions
             .computeExplicitExperimentalFlags(explicitExperimentalFlags)
@@ -1094,6 +1104,8 @@
       ..onDiagnostic = (DiagnosticMessage message) {
         errors.add(message.plainTextFormatted);
       }
+      ..enableUnscheduledExperiments =
+          folderOptions.enableUnscheduledExperiments ?? false
       ..environmentDefines = folderOptions.defines
       ..explicitExperimentalFlags = experimentalFlags
       ..nnbdMode = nnbdMode

diff --git a/pkg/front_end/test/spell_checking_list_common.txt b/pkg/front_end/test/spell_checking_list_common.txt
index dd9f732..93046af 100644
--- a/pkg/front_end/test/spell_checking_list_common.txt
+++ b/pkg/front_end/test/spell_checking_list_common.txt

@@ -488,6 +488,7 @@
 closures
 clue
 code
+coincides
 coinductively
 collapses
 collect
@@ -1397,6 +1398,7 @@
 historically
 hoist
 hoisted
+hoisting
 hold
 holder
 holding
@@ -2574,6 +2576,7 @@
 resynthesize
 retain
 retained
+retains
 rethrow
 rethrowing
 retired
@@ -3218,6 +3221,7 @@
 unresolved
 unsafe
 unsatisfied
+unscheduled
 unserializable
 unsigned
 unsized

diff --git a/pkg/front_end/testcases/unscheduled_experiments/folder.options b/pkg/front_end/testcases/unscheduled_experiments/folder.options
new file mode 100644
index 0000000..b931072
--- /dev/null
+++ b/pkg/front_end/testcases/unscheduled_experiments/folder.options

@@ -0,0 +1 @@
+--enable-unscheduled-experiments
\ No newline at end of file

diff --git a/pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart b/pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart
new file mode 100644
index 0000000..2c51514
--- /dev/null
+++ b/pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart

@@ -0,0 +1,82 @@
+class A {
+  A(int x, int y, {required int z});
+
+  factory A.foo(int x, int y, {required int z}) => new A(x, y, z: z);
+
+  void Function(int x, int y, {required int z}) get property => throw 42;
+
+  void bar(int x, int y, {required int z}) {}
+}
+
+typedef B = A;
+
+foo(int x, int y, {required int z}) {}
+
+extension E on A {
+  method1() {
+    method2(foo: 1, 2); // This call.
+  }
+  method2(int bar, {int? foo}) {}
+}
+
+test(dynamic d, Function f, A a) {
+  void local(int x, int y, {required int z}) {}
+
+  // StaticInvocation.
+  foo(1, 2, z: 3);
+  foo(1, z: 2, 3);
+  foo(z: 1, 2, 3);
+
+  // FactoryConstructorInvocation.
+  new A.foo(1, 2, z: 3);
+  new A.foo(1, z: 2, 3);
+  new A.foo(z: 1, 2, 3);
+  new B.foo(1, 2, z: 3);
+  new B.foo(1, z: 2, 3);
+  new B.foo(z: 1, 2, 3);
+
+  // ConstructorInvocation.
+  new A(1, 2, z: 3);
+  new A(1, z: 2, 3);
+  new A(z: 1, 2, 3);
+  new B(1, 2, z: 3);
+  new B(1, z: 2, 3);
+  new B(z: 1, 2, 3);
+
+  // DynamicInvocation.
+  d(1, 2, z: 3);
+  d(1, z: 2, 3);
+  d(z: 1, 2, 3);
+
+  // FunctionInvocation.
+  f(1, 2, z: 3);
+  f(1, z: 2, 3);
+  f(z: 1, 2, 3);
+
+  // InstanceGetterInvocation.
+  a.property(1, 2, z: 3);
+  a.property(1, z: 2, 3);
+  a.property(z: 1, 2, 3);
+
+  // InstanceInvocation.
+  a.bar(1, 2, z: 3);
+  a.bar(1, z: 2, 3);
+  a.bar(z: 1, 2, 3);
+
+  // LocalFunctionInvocation.
+  local(1, 2, z: 3);
+  local(1, z: 2, 3);
+  local(z: 1, 2, 3);
+}
+
+class Test extends A {
+  Test() : super(1, 2, z: 3);
+
+  test() {
+    super.bar(1, 2, z: 3);
+    super.bar(1, z: 2, 3);
+    super.bar(z: 1, 2, 3);
+  }
+}
+
+main() {}

diff --git a/pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart.strong.expect b/pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart.strong.expect
new file mode 100644
index 0000000..c92d158
--- /dev/null
+++ b/pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart.strong.expect

@@ -0,0 +1,251 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:17:21: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//     method2(foo: 1, 2); // This call.
+//                     ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:27:16: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   foo(1, z: 2, 3);
+//                ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:28:13: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   foo(z: 1, 2, 3);
+//             ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:28:16: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   foo(z: 1, 2, 3);
+//                ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:32:22: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new A.foo(1, z: 2, 3);
+//                      ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:33:19: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new A.foo(z: 1, 2, 3);
+//                   ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:33:22: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new A.foo(z: 1, 2, 3);
+//                      ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:35:22: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new B.foo(1, z: 2, 3);
+//                      ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:36:19: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new B.foo(z: 1, 2, 3);
+//                   ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:36:22: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new B.foo(z: 1, 2, 3);
+//                      ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:40:18: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new A(1, z: 2, 3);
+//                  ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:41:15: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new A(z: 1, 2, 3);
+//               ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:41:18: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new A(z: 1, 2, 3);
+//                  ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:43:18: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new B(1, z: 2, 3);
+//                  ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:44:15: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new B(z: 1, 2, 3);
+//               ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:44:18: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new B(z: 1, 2, 3);
+//                  ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:48:14: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   d(1, z: 2, 3);
+//              ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:49:11: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   d(z: 1, 2, 3);
+//           ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:49:14: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   d(z: 1, 2, 3);
+//              ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:53:14: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   f(1, z: 2, 3);
+//              ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:54:11: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   f(z: 1, 2, 3);
+//           ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:54:14: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   f(z: 1, 2, 3);
+//              ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:58:23: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   a.property(1, z: 2, 3);
+//                       ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:59:20: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   a.property(z: 1, 2, 3);
+//                    ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:59:23: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   a.property(z: 1, 2, 3);
+//                       ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:63:18: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   a.bar(1, z: 2, 3);
+//                  ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:64:15: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   a.bar(z: 1, 2, 3);
+//               ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:64:18: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   a.bar(z: 1, 2, 3);
+//                  ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:68:18: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   local(1, z: 2, 3);
+//                  ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:69:15: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   local(z: 1, 2, 3);
+//               ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:69:18: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   local(z: 1, 2, 3);
+//                  ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:77:24: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//     super.bar(1, z: 2, 3);
+//                        ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:78:21: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//     super.bar(z: 1, 2, 3);
+//                     ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:78:24: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//     super.bar(z: 1, 2, 3);
+//                        ^
+//
+import self as self;
+import "dart:core" as core;
+
+typedef B = self::A;
+class A extends core::Object {
+  constructor •(core::int x, core::int y, {required core::int z = #C1}) → self::A
+    : super core::Object::•()
+    ;
+  static factory foo(core::int x, core::int y, {required core::int z = #C1}) → self::A
+    return new self::A::•(x, y, z: z);
+  get property() → (core::int, core::int, {required z: core::int}) → void
+    return throw 42;
+  method bar(core::int x, core::int y, {required core::int z = #C1}) → void {}
+}
+class Test extends self::A {
+  constructor •() → self::Test
+    : super self::A::•(1, 2, z: 3)
+    ;
+  method test() → dynamic {
+    super.{self::A::bar}(1, 2, z: 3);
+    let final core::int #t1 = 1 in let final core::int #t2 = 2 in super.{self::A::bar}(#t1, 3, z: #t2);
+    let final core::int #t3 = 1 in super.{self::A::bar}(2, 3, z: #t3);
+  }
+}
+extension E on self::A {
+  method method1 = self::E|method1;
+  tearoff method1 = self::E|get#method1;
+  method method2 = self::E|method2;
+  tearoff method2 = self::E|get#method2;
+}
+static method foo(core::int x, core::int y, {required core::int z = #C1}) → dynamic {}
+static method E|method1(lowered final self::A #this) → dynamic {
+  let final self::A #t4 = #this in let final core::int #t5 = 1 in self::E|method2(#t4, 2, foo: #t5);
+}
+static method E|get#method1(lowered final self::A #this) → () → dynamic
+  return () → dynamic => self::E|method1(#this);
+static method E|method2(lowered final self::A #this, core::int bar, {core::int? foo = #C1}) → dynamic {}
+static method E|get#method2(lowered final self::A #this) → (core::int, {foo: core::int?}) → dynamic
+  return (core::int bar, {core::int? foo = #C1}) → dynamic => self::E|method2(#this, bar, foo: foo);
+static method test(dynamic d, core::Function f, self::A a) → dynamic {
+  function local(core::int x, core::int y, {required core::int z = #C1}) → void {}
+  self::foo(1, 2, z: 3);
+  let final core::int #t6 = 1 in let final core::int #t7 = 2 in self::foo(#t6, 3, z: #t7);
+  let final core::int #t8 = 1 in self::foo(2, 3, z: #t8);
+  self::A::foo(1, 2, z: 3);
+  let final core::int #t9 = 1 in let final core::int #t10 = 2 in self::A::foo(#t9, 3, z: #t10);
+  let final core::int #t11 = 1 in self::A::foo(2, 3, z: #t11);
+  self::A::foo(1, 2, z: 3);
+  let final core::int #t12 = 1 in let final core::int #t13 = 2 in self::A::foo(#t12, 3, z: #t13);
+  let final core::int #t14 = 1 in self::A::foo(2, 3, z: #t14);
+  new self::A::•(1, 2, z: 3);
+  let final core::int #t15 = 1 in let final core::int #t16 = 2 in new self::A::•(#t15, 3, z: #t16);
+  let final core::int #t17 = 1 in new self::A::•(2, 3, z: #t17);
+  new self::A::•(1, 2, z: 3);
+  let final core::int #t18 = 1 in let final core::int #t19 = 2 in new self::A::•(#t18, 3, z: #t19);
+  let final core::int #t20 = 1 in new self::A::•(2, 3, z: #t20);
+  d{dynamic}.call(1, 2, z: 3);
+  let final core::int #t21 = 1 in let final core::int #t22 = 2 in d{dynamic}.call(#t21, 3, z: #t22);
+  let final core::int #t23 = 1 in d{dynamic}.call(2, 3, z: #t23);
+  f(1, 2, z: 3);
+  let final core::int #t24 = 1 in let final core::int #t25 = 2 in f(#t24, 3, z: #t25);
+  let final core::int #t26 = 1 in f(2, 3, z: #t26);
+  let final self::A #t27 = a in let final core::int #t28 = 1 in let final core::int #t29 = 2 in let final core::int #t30 = 3 in #t27.{self::A::property}{(core::int, core::int, {required z: core::int}) → void}(#t28, #t29, z: #t30){(core::int, core::int, {required z: core::int}) → void};
+  let final self::A #t31 = a in let final core::int #t32 = 1 in let final core::int #t33 = 2 in let final core::int #t34 = 3 in #t31.{self::A::property}{(core::int, core::int, {required z: core::int}) → void}(#t32, #t34, z: #t33){(core::int, core::int, {required z: core::int}) → void};
+  let final self::A #t35 = a in let final core::int #t36 = 1 in let final core::int #t37 = 2 in let final core::int #t38 = 3 in #t35.{self::A::property}{(core::int, core::int, {required z: core::int}) → void}(#t37, #t38, z: #t36){(core::int, core::int, {required z: core::int}) → void};
+  a.{self::A::bar}(1, 2, z: 3){(core::int, core::int, {required z: core::int}) → void};
+  let final self::A #t39 = a in let final core::int #t40 = 1 in let final core::int #t41 = 2 in #t39.{self::A::bar}(#t40, 3, z: #t41){(core::int, core::int, {required z: core::int}) → void};
+  let final self::A #t42 = a in let final core::int #t43 = 1 in #t42.{self::A::bar}(2, 3, z: #t43){(core::int, core::int, {required z: core::int}) → void};
+  local(1, 2, z: 3){(core::int, core::int, {required z: core::int}) → void};
+  let final core::int #t44 = 1 in let final core::int #t45 = 2 in local(#t44, 3, z: #t45){(core::int, core::int, {required z: core::int}) → void};
+  let final core::int #t46 = 1 in local(2, 3, z: #t46){(core::int, core::int, {required z: core::int}) → void};
+}
+static method main() → dynamic {}
+
+constants  {
+  #C1 = null
+}

diff --git a/pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart.strong.transformed.expect b/pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart.strong.transformed.expect
new file mode 100644
index 0000000..82faf76
--- /dev/null
+++ b/pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart.strong.transformed.expect

@@ -0,0 +1,294 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:17:21: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//     method2(foo: 1, 2); // This call.
+//                     ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:27:16: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   foo(1, z: 2, 3);
+//                ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:28:13: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   foo(z: 1, 2, 3);
+//             ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:28:16: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   foo(z: 1, 2, 3);
+//                ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:32:22: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new A.foo(1, z: 2, 3);
+//                      ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:33:19: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new A.foo(z: 1, 2, 3);
+//                   ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:33:22: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new A.foo(z: 1, 2, 3);
+//                      ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:35:22: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new B.foo(1, z: 2, 3);
+//                      ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:36:19: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new B.foo(z: 1, 2, 3);
+//                   ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:36:22: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new B.foo(z: 1, 2, 3);
+//                      ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:40:18: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new A(1, z: 2, 3);
+//                  ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:41:15: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new A(z: 1, 2, 3);
+//               ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:41:18: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new A(z: 1, 2, 3);
+//                  ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:43:18: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new B(1, z: 2, 3);
+//                  ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:44:15: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new B(z: 1, 2, 3);
+//               ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:44:18: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new B(z: 1, 2, 3);
+//                  ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:48:14: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   d(1, z: 2, 3);
+//              ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:49:11: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   d(z: 1, 2, 3);
+//           ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:49:14: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   d(z: 1, 2, 3);
+//              ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:53:14: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   f(1, z: 2, 3);
+//              ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:54:11: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   f(z: 1, 2, 3);
+//           ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:54:14: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   f(z: 1, 2, 3);
+//              ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:58:23: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   a.property(1, z: 2, 3);
+//                       ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:59:20: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   a.property(z: 1, 2, 3);
+//                    ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:59:23: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   a.property(z: 1, 2, 3);
+//                       ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:63:18: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   a.bar(1, z: 2, 3);
+//                  ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:64:15: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   a.bar(z: 1, 2, 3);
+//               ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:64:18: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   a.bar(z: 1, 2, 3);
+//                  ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:68:18: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   local(1, z: 2, 3);
+//                  ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:69:15: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   local(z: 1, 2, 3);
+//               ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:69:18: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   local(z: 1, 2, 3);
+//                  ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:77:24: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//     super.bar(1, z: 2, 3);
+//                        ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:78:21: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//     super.bar(z: 1, 2, 3);
+//                     ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:78:24: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//     super.bar(z: 1, 2, 3);
+//                        ^
+//
+import self as self;
+import "dart:core" as core;
+
+typedef B = self::A;
+class A extends core::Object {
+  constructor •(core::int x, core::int y, {required core::int z = #C1}) → self::A
+    : super core::Object::•()
+    ;
+  static factory foo(core::int x, core::int y, {required core::int z = #C1}) → self::A
+    return new self::A::•(x, y, z: z);
+  get property() → (core::int, core::int, {required z: core::int}) → void
+    return throw 42;
+  method bar(core::int x, core::int y, {required core::int z = #C1}) → void {}
+}
+class Test extends self::A {
+  constructor •() → self::Test
+    : super self::A::•(1, 2, z: 3)
+    ;
+  method test() → dynamic {
+    super.{self::A::bar}(1, 2, z: 3);
+    let final core::int #t1 = 1 in let final core::int #t2 = 2 in super.{self::A::bar}(#t1, 3, z: #t2);
+    let final core::int #t3 = 1 in super.{self::A::bar}(2, 3, z: #t3);
+  }
+}
+extension E on self::A {
+  method method1 = self::E|method1;
+  tearoff method1 = self::E|get#method1;
+  method method2 = self::E|method2;
+  tearoff method2 = self::E|get#method2;
+}
+static method foo(core::int x, core::int y, {required core::int z = #C1}) → dynamic {}
+static method E|method1(lowered final self::A #this) → dynamic {
+  let final self::A #t4 = #this in let final core::int #t5 = 1 in self::E|method2(#t4, 2, foo: #t5);
+}
+static method E|get#method1(lowered final self::A #this) → () → dynamic
+  return () → dynamic => self::E|method1(#this);
+static method E|method2(lowered final self::A #this, core::int bar, {core::int? foo = #C1}) → dynamic {}
+static method E|get#method2(lowered final self::A #this) → (core::int, {foo: core::int?}) → dynamic
+  return (core::int bar, {core::int? foo = #C1}) → dynamic => self::E|method2(#this, bar, foo: foo);
+static method test(dynamic d, core::Function f, self::A a) → dynamic {
+  function local(core::int x, core::int y, {required core::int z = #C1}) → void {}
+  self::foo(1, 2, z: 3);
+  let final core::int #t6 = 1 in let final core::int #t7 = 2 in self::foo(#t6, 3, z: #t7);
+  let final core::int #t8 = 1 in self::foo(2, 3, z: #t8);
+  self::A::foo(1, 2, z: 3);
+  let final core::int #t9 = 1 in let final core::int #t10 = 2 in self::A::foo(#t9, 3, z: #t10);
+  let final core::int #t11 = 1 in self::A::foo(2, 3, z: #t11);
+  self::A::foo(1, 2, z: 3);
+  let final core::int #t12 = 1 in let final core::int #t13 = 2 in self::A::foo(#t12, 3, z: #t13);
+  let final core::int #t14 = 1 in self::A::foo(2, 3, z: #t14);
+  new self::A::•(1, 2, z: 3);
+  let final core::int #t15 = 1 in let final core::int #t16 = 2 in new self::A::•(#t15, 3, z: #t16);
+  let final core::int #t17 = 1 in new self::A::•(2, 3, z: #t17);
+  new self::A::•(1, 2, z: 3);
+  let final core::int #t18 = 1 in let final core::int #t19 = 2 in new self::A::•(#t18, 3, z: #t19);
+  let final core::int #t20 = 1 in new self::A::•(2, 3, z: #t20);
+  d{dynamic}.call(1, 2, z: 3);
+  let final core::int #t21 = 1 in let final core::int #t22 = 2 in d{dynamic}.call(#t21, 3, z: #t22);
+  let final core::int #t23 = 1 in d{dynamic}.call(2, 3, z: #t23);
+  f(1, 2, z: 3);
+  let final core::int #t24 = 1 in let final core::int #t25 = 2 in f(#t24, 3, z: #t25);
+  let final core::int #t26 = 1 in f(2, 3, z: #t26);
+  let final self::A #t27 = a in let final core::int #t28 = 1 in let final core::int #t29 = 2 in let final core::int #t30 = 3 in #t27.{self::A::property}{(core::int, core::int, {required z: core::int}) → void}(#t28, #t29, z: #t30){(core::int, core::int, {required z: core::int}) → void};
+  let final self::A #t31 = a in let final core::int #t32 = 1 in let final core::int #t33 = 2 in let final core::int #t34 = 3 in #t31.{self::A::property}{(core::int, core::int, {required z: core::int}) → void}(#t32, #t34, z: #t33){(core::int, core::int, {required z: core::int}) → void};
+  let final self::A #t35 = a in let final core::int #t36 = 1 in let final core::int #t37 = 2 in let final core::int #t38 = 3 in #t35.{self::A::property}{(core::int, core::int, {required z: core::int}) → void}(#t37, #t38, z: #t36){(core::int, core::int, {required z: core::int}) → void};
+  a.{self::A::bar}(1, 2, z: 3){(core::int, core::int, {required z: core::int}) → void};
+  let final self::A #t39 = a in let final core::int #t40 = 1 in let final core::int #t41 = 2 in #t39.{self::A::bar}(#t40, 3, z: #t41){(core::int, core::int, {required z: core::int}) → void};
+  let final self::A #t42 = a in let final core::int #t43 = 1 in #t42.{self::A::bar}(2, 3, z: #t43){(core::int, core::int, {required z: core::int}) → void};
+  local(1, 2, z: 3){(core::int, core::int, {required z: core::int}) → void};
+  let final core::int #t44 = 1 in let final core::int #t45 = 2 in local(#t44, 3, z: #t45){(core::int, core::int, {required z: core::int}) → void};
+  let final core::int #t46 = 1 in local(2, 3, z: #t46){(core::int, core::int, {required z: core::int}) → void};
+}
+static method main() → dynamic {}
+
+constants  {
+  #C1 = null
+}
+
+Extra constant evaluation status:
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:77:15 -> IntConstant(1)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:77:21 -> IntConstant(2)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:78:18 -> IntConstant(1)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:17:18 -> IntConstant(1)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:27:7 -> IntConstant(1)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:27:13 -> IntConstant(2)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:28:10 -> IntConstant(1)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:32:13 -> IntConstant(1)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:32:19 -> IntConstant(2)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:33:16 -> IntConstant(1)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:35:13 -> IntConstant(1)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:35:19 -> IntConstant(2)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:36:16 -> IntConstant(1)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:40:9 -> IntConstant(1)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:40:15 -> IntConstant(2)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:41:12 -> IntConstant(1)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:43:9 -> IntConstant(1)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:43:15 -> IntConstant(2)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:44:12 -> IntConstant(1)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:48:5 -> IntConstant(1)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:48:11 -> IntConstant(2)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:49:8 -> IntConstant(1)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:53:5 -> IntConstant(1)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:53:11 -> IntConstant(2)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:54:8 -> IntConstant(1)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:57:14 -> IntConstant(1)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:57:17 -> IntConstant(2)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:57:23 -> IntConstant(3)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:58:14 -> IntConstant(1)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:58:23 -> IntConstant(3)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:58:20 -> IntConstant(2)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:59:20 -> IntConstant(2)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:59:23 -> IntConstant(3)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:59:17 -> IntConstant(1)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:63:9 -> IntConstant(1)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:63:15 -> IntConstant(2)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:64:12 -> IntConstant(1)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:68:9 -> IntConstant(1)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:68:15 -> IntConstant(2)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:69:12 -> IntConstant(1)
+Extra constant evaluation: evaluated: 155, effectively constant: 40

diff --git a/pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart.textual_outline.expect b/pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart.textual_outline.expect
new file mode 100644
index 0000000..903b3b6
--- /dev/null
+++ b/pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart.textual_outline.expect

@@ -0,0 +1,23 @@
+class A {
+  A(int x, int y, {required int z});
+  factory A.foo(int x, int y, {required int z}) => new A(x, y, z: z);
+  void Function(int x, int y, {required int z}) get property => throw 42;
+  void bar(int x, int y, {required int z}) {}
+}
+
+typedef B = A;
+foo(int x, int y, {required int z}) {}
+
+extension E on A {
+  method1() {}
+  method2(int bar, {int? foo}) {}
+}
+
+test(dynamic d, Function f, A a) {}
+
+class Test extends A {
+  Test() : super(1, 2, z: 3);
+  test() {}
+}
+
+main() {}

diff --git a/pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart.textual_outline_modelled.expect b/pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart.textual_outline_modelled.expect
new file mode 100644
index 0000000..f0b79da
--- /dev/null
+++ b/pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart.textual_outline_modelled.expect

@@ -0,0 +1,21 @@
+class A {
+  A(int x, int y, {required int z});
+  factory A.foo(int x, int y, {required int z}) => new A(x, y, z: z);
+  void Function(int x, int y, {required int z}) get property => throw 42;
+  void bar(int x, int y, {required int z}) {}
+}
+
+class Test extends A {
+  Test() : super(1, 2, z: 3);
+  test() {}
+}
+
+extension E on A {
+  method1() {}
+  method2(int bar, {int? foo}) {}
+}
+
+foo(int x, int y, {required int z}) {}
+main() {}
+test(dynamic d, Function f, A a) {}
+typedef B = A;

diff --git a/pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart.weak.expect b/pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart.weak.expect
new file mode 100644
index 0000000..c92d158
--- /dev/null
+++ b/pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart.weak.expect

@@ -0,0 +1,251 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:17:21: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//     method2(foo: 1, 2); // This call.
+//                     ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:27:16: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   foo(1, z: 2, 3);
+//                ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:28:13: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   foo(z: 1, 2, 3);
+//             ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:28:16: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   foo(z: 1, 2, 3);
+//                ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:32:22: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new A.foo(1, z: 2, 3);
+//                      ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:33:19: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new A.foo(z: 1, 2, 3);
+//                   ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:33:22: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new A.foo(z: 1, 2, 3);
+//                      ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:35:22: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new B.foo(1, z: 2, 3);
+//                      ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:36:19: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new B.foo(z: 1, 2, 3);
+//                   ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:36:22: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new B.foo(z: 1, 2, 3);
+//                      ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:40:18: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new A(1, z: 2, 3);
+//                  ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:41:15: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new A(z: 1, 2, 3);
+//               ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:41:18: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new A(z: 1, 2, 3);
+//                  ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:43:18: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new B(1, z: 2, 3);
+//                  ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:44:15: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new B(z: 1, 2, 3);
+//               ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:44:18: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new B(z: 1, 2, 3);
+//                  ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:48:14: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   d(1, z: 2, 3);
+//              ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:49:11: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   d(z: 1, 2, 3);
+//           ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:49:14: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   d(z: 1, 2, 3);
+//              ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:53:14: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   f(1, z: 2, 3);
+//              ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:54:11: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   f(z: 1, 2, 3);
+//           ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:54:14: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   f(z: 1, 2, 3);
+//              ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:58:23: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   a.property(1, z: 2, 3);
+//                       ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:59:20: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   a.property(z: 1, 2, 3);
+//                    ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:59:23: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   a.property(z: 1, 2, 3);
+//                       ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:63:18: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   a.bar(1, z: 2, 3);
+//                  ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:64:15: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   a.bar(z: 1, 2, 3);
+//               ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:64:18: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   a.bar(z: 1, 2, 3);
+//                  ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:68:18: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   local(1, z: 2, 3);
+//                  ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:69:15: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   local(z: 1, 2, 3);
+//               ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:69:18: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   local(z: 1, 2, 3);
+//                  ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:77:24: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//     super.bar(1, z: 2, 3);
+//                        ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:78:21: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//     super.bar(z: 1, 2, 3);
+//                     ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:78:24: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//     super.bar(z: 1, 2, 3);
+//                        ^
+//
+import self as self;
+import "dart:core" as core;
+
+typedef B = self::A;
+class A extends core::Object {
+  constructor •(core::int x, core::int y, {required core::int z = #C1}) → self::A
+    : super core::Object::•()
+    ;
+  static factory foo(core::int x, core::int y, {required core::int z = #C1}) → self::A
+    return new self::A::•(x, y, z: z);
+  get property() → (core::int, core::int, {required z: core::int}) → void
+    return throw 42;
+  method bar(core::int x, core::int y, {required core::int z = #C1}) → void {}
+}
+class Test extends self::A {
+  constructor •() → self::Test
+    : super self::A::•(1, 2, z: 3)
+    ;
+  method test() → dynamic {
+    super.{self::A::bar}(1, 2, z: 3);
+    let final core::int #t1 = 1 in let final core::int #t2 = 2 in super.{self::A::bar}(#t1, 3, z: #t2);
+    let final core::int #t3 = 1 in super.{self::A::bar}(2, 3, z: #t3);
+  }
+}
+extension E on self::A {
+  method method1 = self::E|method1;
+  tearoff method1 = self::E|get#method1;
+  method method2 = self::E|method2;
+  tearoff method2 = self::E|get#method2;
+}
+static method foo(core::int x, core::int y, {required core::int z = #C1}) → dynamic {}
+static method E|method1(lowered final self::A #this) → dynamic {
+  let final self::A #t4 = #this in let final core::int #t5 = 1 in self::E|method2(#t4, 2, foo: #t5);
+}
+static method E|get#method1(lowered final self::A #this) → () → dynamic
+  return () → dynamic => self::E|method1(#this);
+static method E|method2(lowered final self::A #this, core::int bar, {core::int? foo = #C1}) → dynamic {}
+static method E|get#method2(lowered final self::A #this) → (core::int, {foo: core::int?}) → dynamic
+  return (core::int bar, {core::int? foo = #C1}) → dynamic => self::E|method2(#this, bar, foo: foo);
+static method test(dynamic d, core::Function f, self::A a) → dynamic {
+  function local(core::int x, core::int y, {required core::int z = #C1}) → void {}
+  self::foo(1, 2, z: 3);
+  let final core::int #t6 = 1 in let final core::int #t7 = 2 in self::foo(#t6, 3, z: #t7);
+  let final core::int #t8 = 1 in self::foo(2, 3, z: #t8);
+  self::A::foo(1, 2, z: 3);
+  let final core::int #t9 = 1 in let final core::int #t10 = 2 in self::A::foo(#t9, 3, z: #t10);
+  let final core::int #t11 = 1 in self::A::foo(2, 3, z: #t11);
+  self::A::foo(1, 2, z: 3);
+  let final core::int #t12 = 1 in let final core::int #t13 = 2 in self::A::foo(#t12, 3, z: #t13);
+  let final core::int #t14 = 1 in self::A::foo(2, 3, z: #t14);
+  new self::A::•(1, 2, z: 3);
+  let final core::int #t15 = 1 in let final core::int #t16 = 2 in new self::A::•(#t15, 3, z: #t16);
+  let final core::int #t17 = 1 in new self::A::•(2, 3, z: #t17);
+  new self::A::•(1, 2, z: 3);
+  let final core::int #t18 = 1 in let final core::int #t19 = 2 in new self::A::•(#t18, 3, z: #t19);
+  let final core::int #t20 = 1 in new self::A::•(2, 3, z: #t20);
+  d{dynamic}.call(1, 2, z: 3);
+  let final core::int #t21 = 1 in let final core::int #t22 = 2 in d{dynamic}.call(#t21, 3, z: #t22);
+  let final core::int #t23 = 1 in d{dynamic}.call(2, 3, z: #t23);
+  f(1, 2, z: 3);
+  let final core::int #t24 = 1 in let final core::int #t25 = 2 in f(#t24, 3, z: #t25);
+  let final core::int #t26 = 1 in f(2, 3, z: #t26);
+  let final self::A #t27 = a in let final core::int #t28 = 1 in let final core::int #t29 = 2 in let final core::int #t30 = 3 in #t27.{self::A::property}{(core::int, core::int, {required z: core::int}) → void}(#t28, #t29, z: #t30){(core::int, core::int, {required z: core::int}) → void};
+  let final self::A #t31 = a in let final core::int #t32 = 1 in let final core::int #t33 = 2 in let final core::int #t34 = 3 in #t31.{self::A::property}{(core::int, core::int, {required z: core::int}) → void}(#t32, #t34, z: #t33){(core::int, core::int, {required z: core::int}) → void};
+  let final self::A #t35 = a in let final core::int #t36 = 1 in let final core::int #t37 = 2 in let final core::int #t38 = 3 in #t35.{self::A::property}{(core::int, core::int, {required z: core::int}) → void}(#t37, #t38, z: #t36){(core::int, core::int, {required z: core::int}) → void};
+  a.{self::A::bar}(1, 2, z: 3){(core::int, core::int, {required z: core::int}) → void};
+  let final self::A #t39 = a in let final core::int #t40 = 1 in let final core::int #t41 = 2 in #t39.{self::A::bar}(#t40, 3, z: #t41){(core::int, core::int, {required z: core::int}) → void};
+  let final self::A #t42 = a in let final core::int #t43 = 1 in #t42.{self::A::bar}(2, 3, z: #t43){(core::int, core::int, {required z: core::int}) → void};
+  local(1, 2, z: 3){(core::int, core::int, {required z: core::int}) → void};
+  let final core::int #t44 = 1 in let final core::int #t45 = 2 in local(#t44, 3, z: #t45){(core::int, core::int, {required z: core::int}) → void};
+  let final core::int #t46 = 1 in local(2, 3, z: #t46){(core::int, core::int, {required z: core::int}) → void};
+}
+static method main() → dynamic {}
+
+constants  {
+  #C1 = null
+}

diff --git a/pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart.weak.outline.expect b/pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart.weak.outline.expect
new file mode 100644
index 0000000..23ee911
--- /dev/null
+++ b/pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart.weak.outline.expect

@@ -0,0 +1,41 @@
+library /*isNonNullableByDefault*/;
+import self as self;
+import "dart:core" as core;
+
+typedef B = self::A;
+class A extends core::Object {
+  constructor •(core::int x, core::int y, {required core::int z}) → self::A
+    ;
+  static factory foo(core::int x, core::int y, {required core::int z}) → self::A
+    ;
+  get property() → (core::int, core::int, {required z: core::int}) → void
+    ;
+  method bar(core::int x, core::int y, {required core::int z}) → void
+    ;
+}
+class Test extends self::A {
+  constructor •() → self::Test
+    ;
+  method test() → dynamic
+    ;
+}
+extension E on self::A {
+  method method1 = self::E|method1;
+  tearoff method1 = self::E|get#method1;
+  method method2 = self::E|method2;
+  tearoff method2 = self::E|get#method2;
+}
+static method foo(core::int x, core::int y, {required core::int z}) → dynamic
+  ;
+static method E|method1(lowered final self::A #this) → dynamic
+  ;
+static method E|get#method1(lowered final self::A #this) → () → dynamic
+  return () → dynamic => self::E|method1(#this);
+static method E|method2(lowered final self::A #this, core::int bar, {core::int? foo}) → dynamic
+  ;
+static method E|get#method2(lowered final self::A #this) → (core::int, {foo: core::int?}) → dynamic
+  return (core::int bar, {core::int? foo}) → dynamic => self::E|method2(#this, bar, foo: foo);
+static method test(dynamic d, core::Function f, self::A a) → dynamic
+  ;
+static method main() → dynamic
+  ;

diff --git a/pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart.weak.transformed.expect b/pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart.weak.transformed.expect
new file mode 100644
index 0000000..82faf76
--- /dev/null
+++ b/pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart.weak.transformed.expect

@@ -0,0 +1,294 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:17:21: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//     method2(foo: 1, 2); // This call.
+//                     ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:27:16: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   foo(1, z: 2, 3);
+//                ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:28:13: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   foo(z: 1, 2, 3);
+//             ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:28:16: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   foo(z: 1, 2, 3);
+//                ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:32:22: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new A.foo(1, z: 2, 3);
+//                      ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:33:19: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new A.foo(z: 1, 2, 3);
+//                   ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:33:22: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new A.foo(z: 1, 2, 3);
+//                      ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:35:22: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new B.foo(1, z: 2, 3);
+//                      ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:36:19: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new B.foo(z: 1, 2, 3);
+//                   ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:36:22: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new B.foo(z: 1, 2, 3);
+//                      ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:40:18: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new A(1, z: 2, 3);
+//                  ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:41:15: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new A(z: 1, 2, 3);
+//               ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:41:18: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new A(z: 1, 2, 3);
+//                  ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:43:18: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new B(1, z: 2, 3);
+//                  ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:44:15: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new B(z: 1, 2, 3);
+//               ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:44:18: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   new B(z: 1, 2, 3);
+//                  ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:48:14: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   d(1, z: 2, 3);
+//              ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:49:11: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   d(z: 1, 2, 3);
+//           ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:49:14: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   d(z: 1, 2, 3);
+//              ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:53:14: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   f(1, z: 2, 3);
+//              ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:54:11: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   f(z: 1, 2, 3);
+//           ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:54:14: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   f(z: 1, 2, 3);
+//              ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:58:23: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   a.property(1, z: 2, 3);
+//                       ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:59:20: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   a.property(z: 1, 2, 3);
+//                    ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:59:23: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   a.property(z: 1, 2, 3);
+//                       ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:63:18: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   a.bar(1, z: 2, 3);
+//                  ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:64:15: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   a.bar(z: 1, 2, 3);
+//               ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:64:18: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   a.bar(z: 1, 2, 3);
+//                  ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:68:18: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   local(1, z: 2, 3);
+//                  ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:69:15: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   local(z: 1, 2, 3);
+//               ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:69:18: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//   local(z: 1, 2, 3);
+//                  ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:77:24: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//     super.bar(1, z: 2, 3);
+//                        ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:78:21: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//     super.bar(z: 1, 2, 3);
+//                     ^
+//
+// pkg/front_end/testcases/unscheduled_experiments/named_arguments_anywhere/all_kinds.dart:78:24: Error: Place positional arguments before named arguments.
+// Try moving the positional argument before the named arguments, or add a name to the argument.
+//     super.bar(z: 1, 2, 3);
+//                        ^
+//
+import self as self;
+import "dart:core" as core;
+
+typedef B = self::A;
+class A extends core::Object {
+  constructor •(core::int x, core::int y, {required core::int z = #C1}) → self::A
+    : super core::Object::•()
+    ;
+  static factory foo(core::int x, core::int y, {required core::int z = #C1}) → self::A
+    return new self::A::•(x, y, z: z);
+  get property() → (core::int, core::int, {required z: core::int}) → void
+    return throw 42;
+  method bar(core::int x, core::int y, {required core::int z = #C1}) → void {}
+}
+class Test extends self::A {
+  constructor •() → self::Test
+    : super self::A::•(1, 2, z: 3)
+    ;
+  method test() → dynamic {
+    super.{self::A::bar}(1, 2, z: 3);
+    let final core::int #t1 = 1 in let final core::int #t2 = 2 in super.{self::A::bar}(#t1, 3, z: #t2);
+    let final core::int #t3 = 1 in super.{self::A::bar}(2, 3, z: #t3);
+  }
+}
+extension E on self::A {
+  method method1 = self::E|method1;
+  tearoff method1 = self::E|get#method1;
+  method method2 = self::E|method2;
+  tearoff method2 = self::E|get#method2;
+}
+static method foo(core::int x, core::int y, {required core::int z = #C1}) → dynamic {}
+static method E|method1(lowered final self::A #this) → dynamic {
+  let final self::A #t4 = #this in let final core::int #t5 = 1 in self::E|method2(#t4, 2, foo: #t5);
+}
+static method E|get#method1(lowered final self::A #this) → () → dynamic
+  return () → dynamic => self::E|method1(#this);
+static method E|method2(lowered final self::A #this, core::int bar, {core::int? foo = #C1}) → dynamic {}
+static method E|get#method2(lowered final self::A #this) → (core::int, {foo: core::int?}) → dynamic
+  return (core::int bar, {core::int? foo = #C1}) → dynamic => self::E|method2(#this, bar, foo: foo);
+static method test(dynamic d, core::Function f, self::A a) → dynamic {
+  function local(core::int x, core::int y, {required core::int z = #C1}) → void {}
+  self::foo(1, 2, z: 3);
+  let final core::int #t6 = 1 in let final core::int #t7 = 2 in self::foo(#t6, 3, z: #t7);
+  let final core::int #t8 = 1 in self::foo(2, 3, z: #t8);
+  self::A::foo(1, 2, z: 3);
+  let final core::int #t9 = 1 in let final core::int #t10 = 2 in self::A::foo(#t9, 3, z: #t10);
+  let final core::int #t11 = 1 in self::A::foo(2, 3, z: #t11);
+  self::A::foo(1, 2, z: 3);
+  let final core::int #t12 = 1 in let final core::int #t13 = 2 in self::A::foo(#t12, 3, z: #t13);
+  let final core::int #t14 = 1 in self::A::foo(2, 3, z: #t14);
+  new self::A::•(1, 2, z: 3);
+  let final core::int #t15 = 1 in let final core::int #t16 = 2 in new self::A::•(#t15, 3, z: #t16);
+  let final core::int #t17 = 1 in new self::A::•(2, 3, z: #t17);
+  new self::A::•(1, 2, z: 3);
+  let final core::int #t18 = 1 in let final core::int #t19 = 2 in new self::A::•(#t18, 3, z: #t19);
+  let final core::int #t20 = 1 in new self::A::•(2, 3, z: #t20);
+  d{dynamic}.call(1, 2, z: 3);
+  let final core::int #t21 = 1 in let final core::int #t22 = 2 in d{dynamic}.call(#t21, 3, z: #t22);
+  let final core::int #t23 = 1 in d{dynamic}.call(2, 3, z: #t23);
+  f(1, 2, z: 3);
+  let final core::int #t24 = 1 in let final core::int #t25 = 2 in f(#t24, 3, z: #t25);
+  let final core::int #t26 = 1 in f(2, 3, z: #t26);
+  let final self::A #t27 = a in let final core::int #t28 = 1 in let final core::int #t29 = 2 in let final core::int #t30 = 3 in #t27.{self::A::property}{(core::int, core::int, {required z: core::int}) → void}(#t28, #t29, z: #t30){(core::int, core::int, {required z: core::int}) → void};
+  let final self::A #t31 = a in let final core::int #t32 = 1 in let final core::int #t33 = 2 in let final core::int #t34 = 3 in #t31.{self::A::property}{(core::int, core::int, {required z: core::int}) → void}(#t32, #t34, z: #t33){(core::int, core::int, {required z: core::int}) → void};
+  let final self::A #t35 = a in let final core::int #t36 = 1 in let final core::int #t37 = 2 in let final core::int #t38 = 3 in #t35.{self::A::property}{(core::int, core::int, {required z: core::int}) → void}(#t37, #t38, z: #t36){(core::int, core::int, {required z: core::int}) → void};
+  a.{self::A::bar}(1, 2, z: 3){(core::int, core::int, {required z: core::int}) → void};
+  let final self::A #t39 = a in let final core::int #t40 = 1 in let final core::int #t41 = 2 in #t39.{self::A::bar}(#t40, 3, z: #t41){(core::int, core::int, {required z: core::int}) → void};
+  let final self::A #t42 = a in let final core::int #t43 = 1 in #t42.{self::A::bar}(2, 3, z: #t43){(core::int, core::int, {required z: core::int}) → void};
+  local(1, 2, z: 3){(core::int, core::int, {required z: core::int}) → void};
+  let final core::int #t44 = 1 in let final core::int #t45 = 2 in local(#t44, 3, z: #t45){(core::int, core::int, {required z: core::int}) → void};
+  let final core::int #t46 = 1 in local(2, 3, z: #t46){(core::int, core::int, {required z: core::int}) → void};
+}
+static method main() → dynamic {}
+
+constants  {
+  #C1 = null
+}
+
+Extra constant evaluation status:
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:77:15 -> IntConstant(1)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:77:21 -> IntConstant(2)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:78:18 -> IntConstant(1)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:17:18 -> IntConstant(1)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:27:7 -> IntConstant(1)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:27:13 -> IntConstant(2)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:28:10 -> IntConstant(1)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:32:13 -> IntConstant(1)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:32:19 -> IntConstant(2)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:33:16 -> IntConstant(1)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:35:13 -> IntConstant(1)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:35:19 -> IntConstant(2)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:36:16 -> IntConstant(1)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:40:9 -> IntConstant(1)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:40:15 -> IntConstant(2)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:41:12 -> IntConstant(1)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:43:9 -> IntConstant(1)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:43:15 -> IntConstant(2)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:44:12 -> IntConstant(1)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:48:5 -> IntConstant(1)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:48:11 -> IntConstant(2)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:49:8 -> IntConstant(1)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:53:5 -> IntConstant(1)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:53:11 -> IntConstant(2)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:54:8 -> IntConstant(1)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:57:14 -> IntConstant(1)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:57:17 -> IntConstant(2)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:57:23 -> IntConstant(3)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:58:14 -> IntConstant(1)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:58:23 -> IntConstant(3)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:58:20 -> IntConstant(2)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:59:20 -> IntConstant(2)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:59:23 -> IntConstant(3)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:59:17 -> IntConstant(1)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:63:9 -> IntConstant(1)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:63:15 -> IntConstant(2)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:64:12 -> IntConstant(1)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:68:9 -> IntConstant(1)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:68:15 -> IntConstant(2)
+Evaluated: VariableGet @ org-dartlang-testcase:///all_kinds.dart:69:12 -> IntConstant(1)
+Extra constant evaluation: evaluated: 155, effectively constant: 40

diff --git a/pkg/front_end/tool/_fasta/command_line.dart b/pkg/front_end/tool/_fasta/command_line.dart
index 61caaf3..d8a5ab1 100644
--- a/pkg/front_end/tool/_fasta/command_line.dart
+++ b/pkg/front_end/tool/_fasta/command_line.dart

@@ -60,6 +60,7 @@
   Options.compileSdk,
   Options.dumpIr,
   Options.enableExperiment,
+  Options.enableUnscheduledExperiments,
   Options.excludeSource,
   Options.omitPlatform,
   Options.fatal,
@@ -188,6 +189,9 @@
       ? NnbdMode.Agnostic
       : (nnbdStrongMode ? NnbdMode.Strong : NnbdMode.Weak);
 
+  final bool enableUnscheduledExperiments =
+      Options.enableUnscheduledExperiments.read(parsedOptions);
+
   final bool warnOnReachabilityCheck =
       Options.warnOnReachabilityCheck.read(parsedOptions);
 
@@ -247,6 +251,7 @@
     ..explicitExperimentalFlags = explicitExperimentalFlags
     ..environmentDefines = noDefines ? null : parsedOptions.defines
     ..nnbdMode = nnbdMode
+    ..enableUnscheduledExperiments = enableUnscheduledExperiments
     ..additionalDills = linkDependencies
     ..emitDeps = !noDeps
     ..warnOnReachabilityCheck = warnOnReachabilityCheck