diff --git a/DEPS b/DEPS
index 88be3b3..b5cc604 100644
--- a/DEPS
+++ b/DEPS
@@ -154,7 +154,7 @@
   "term_glyph_rev": "6a0f9b6fb645ba75e7a00a4e20072678327a0347",
   "test_reflective_loader_tag": "0.1.9",
   "test_rev": "e37a93bbeae23b215972d1659ac865d71287ff6a",
-  "tflite_native_rev": "3c777c40608a2a9f1427bfe0028ab48e7116b4c1",
+  "tflite_native_rev": "0.4.0+1",
   "typed_data_tag": "f94fc57b8e8c0e4fe4ff6cfd8290b94af52d3719",
   "usage_tag": "3.4.0",
   "vector_math_rev": "0c9f5d68c047813a6dcdeb88ba7a42daddf25025",
diff --git a/pkg/analyzer/lib/src/dart/element/element.dart b/pkg/analyzer/lib/src/dart/element/element.dart
index a87e07a..77c0646 100644
--- a/pkg/analyzer/lib/src/dart/element/element.dart
+++ b/pkg/analyzer/lib/src/dart/element/element.dart
@@ -42,7 +42,6 @@
 import 'package:analyzer/src/generated/utilities_dart.dart';
 import 'package:analyzer/src/generated/utilities_general.dart';
 import 'package:analyzer/src/summary/idl.dart';
-import 'package:analyzer/src/summary2/linked_element_builder.dart';
 import 'package:analyzer/src/summary2/linked_unit_context.dart';
 import 'package:analyzer/src/summary2/reference.dart';
 import 'package:analyzer/src/util/comment.dart';
@@ -1298,15 +1297,16 @@
     if (_enums != null) return _enums;
 
     if (linkedNode != null) {
+      var containerRef = reference.getChild('@enum');
       CompilationUnit linkedNode = this.linkedNode;
-      _enums = <ClassElement>[];
-      for (var node in linkedNode.declarations) {
-        if (node is EnumDeclaration) {
-          var element = _elementBuilder.enumDeclaration(node);
-          _enums.add(element);
+      _enums = linkedNode.declarations.whereType<EnumDeclaration>().map((node) {
+        var name = node.name.name;
+        var reference = containerRef.getChild(name);
+        if (reference.hasElementFor(node)) {
+          return reference.element as EnumElementImpl;
         }
-      }
-      return _enums;
+        return EnumElementImpl.forLinkedNode(this, reference, node);
+      }).toList();
     }
 
     return _enums ??= const <ClassElement>[];
@@ -1328,11 +1328,19 @@
 
     if (linkedNode != null) {
       CompilationUnit linkedNode = this.linkedNode;
+      var containerRef = reference.getChild('@extension');
       _extensions = <ExtensionElement>[];
       for (var node in linkedNode.declarations) {
         if (node is ExtensionDeclaration) {
-          var element = _elementBuilder.extensionDeclaration(node);
-          _extensions.add(element);
+          var refName = linkedContext.getExtensionRefName(node);
+          var reference = containerRef.getChild(refName);
+          if (reference.hasElementFor(node)) {
+            _extensions.add(reference.element);
+          } else {
+            _extensions.add(
+              ExtensionElementImpl.forLinkedNode(this, reference, node),
+            );
+          }
         }
       }
       return _extensions;
@@ -1355,14 +1363,18 @@
 
     if (linkedNode != null) {
       CompilationUnit linkedNode = this.linkedNode;
-      _functions = <FunctionElement>[];
-      for (var node in linkedNode.declarations) {
-        if (node is FunctionDeclaration && node.propertyKeyword == null) {
-          var element = _elementBuilder.functionDeclaration(node);
-          _functions.add(element as FunctionElement);
+      var containerRef = reference.getChild('@function');
+      return _functions = linkedNode.declarations
+          .whereType<FunctionDeclaration>()
+          .where((node) => !node.isGetter && !node.isSetter)
+          .map((node) {
+        var name = node.name.name;
+        var reference = containerRef.getChild(name);
+        if (reference.hasElementFor(node)) {
+          return reference.element as FunctionElementImpl;
         }
-      }
-      return _functions;
+        return FunctionElementImpl.forLinkedNode(this, reference, node);
+      }).toList();
     }
     return _functions ?? const <FunctionElement>[];
   }
@@ -1382,17 +1394,23 @@
 
     if (linkedNode != null) {
       CompilationUnit linkedNode = this.linkedNode;
-      _typeAliases = <FunctionTypeAliasElement>[];
-      for (var node in linkedNode.declarations) {
+      var containerRef = reference.getChild('@typeAlias');
+      return _typeAliases = linkedNode.declarations.where((node) {
+        return node is FunctionTypeAlias || node is GenericTypeAlias;
+      }).map((node) {
+        String name;
         if (node is FunctionTypeAlias) {
-          var element = _elementBuilder.functionTypeAlias(node);
-          _typeAliases.add(element);
-        } else if (node is GenericTypeAlias) {
-          var element = _elementBuilder.genericTypeAlias(node);
-          _typeAliases.add(element);
+          name = node.name.name;
+        } else {
+          name = (node as GenericTypeAlias).name.name;
         }
-      }
-      return _typeAliases;
+
+        var reference = containerRef.getChild(name);
+        if (reference.hasElementFor(node)) {
+          return reference.element as GenericTypeAliasElementImpl;
+        }
+        return GenericTypeAliasElementImpl.forLinkedNode(this, reference, node);
+      }).toList();
     }
 
     return _typeAliases ?? const <FunctionTypeAliasElement>[];
@@ -1424,14 +1442,16 @@
 
     if (linkedNode != null) {
       CompilationUnit linkedNode = this.linkedNode;
-      _mixins = <ClassElement>[];
-      for (var node in linkedNode.declarations) {
-        if (node is MixinDeclaration) {
-          var element = _elementBuilder.mixinDeclaration(node);
-          _mixins.add(element);
+      var containerRef = reference.getChild('@mixin');
+      var declarations = linkedNode.declarations;
+      return _mixins = declarations.whereType<MixinDeclaration>().map((node) {
+        var name = node.name.name;
+        var reference = containerRef.getChild(name);
+        if (reference.hasElementFor(node)) {
+          return reference.element as MixinElementImpl;
         }
-      }
-      return _mixins;
+        return MixinElementImpl.forLinkedNode(this, reference, node);
+      }).toList();
     }
 
     return _mixins ?? const <ClassElement>[];
@@ -1483,14 +1503,24 @@
 
     if (linkedNode != null) {
       CompilationUnit linkedNode = this.linkedNode;
+      var containerRef = reference.getChild('@class');
       _types = <ClassElement>[];
       for (var node in linkedNode.declarations) {
+        String name;
         if (node is ClassDeclaration) {
-          var element = _elementBuilder.classDeclaration(node);
-          _types.add(element);
+          name = node.name.name;
         } else if (node is ClassTypeAlias) {
-          var element = _elementBuilder.classTypeAlias(node);
-          _types.add(element);
+          name = node.name.name;
+        } else {
+          continue;
+        }
+        var reference = containerRef.getChild(name);
+        if (reference.hasElementFor(node)) {
+          _types.add(reference.element);
+        } else {
+          _types.add(
+            ClassElementImpl.forLinkedNode(this, reference, node),
+          );
         }
       }
       return _types;
@@ -1623,13 +1653,18 @@
       var variableList = <TopLevelVariableElement>[];
       variableMap[unit] = variableList;
 
-      var elementBuilder = unit._elementBuilder;
       var unitNode = unit.linkedContext.unit_withDeclarations;
       var unitDeclarations = unitNode.declarations;
 
       var variables = context.topLevelVariables(unitNode);
       for (var variable in variables) {
-        var variableElement = elementBuilder.topLevelVariable(variable);
+        var name = variable.name.name;
+        var reference = unit.reference.getChild('@variable').getChild(name);
+        var variableElement = TopLevelVariableElementImpl.forLinkedNodeFactory(
+          unit,
+          reference,
+          variable,
+        );
         variableList.add(variableElement);
 
         accessorList.add(variableElement.getter);
@@ -1645,9 +1680,15 @@
           if (!isGetter && !isSetter) continue;
 
           var name = node.name.name;
+          var containerRef = isGetter
+              ? unit.reference.getChild('@getter')
+              : unit.reference.getChild('@setter');
 
-          var accessorElement = elementBuilder.functionDeclaration(node)
-              as PropertyAccessorElementImpl;
+          var accessorElement = PropertyAccessorElementImpl.forLinkedNode(
+            unit,
+            containerRef.getChild(name),
+            node,
+          );
           accessorList.add(accessorElement);
 
           var fieldRef = unit.reference.getChild('@field').getChild(name);
@@ -2988,10 +3029,6 @@
     return _enclosingElement?.typeParameterContext;
   }
 
-  LinkedElementBuilder get _elementBuilder {
-    return linkedContext.elementBuilder;
-  }
-
   NullabilitySuffix get _noneOrStarSuffix {
     return library?.isNonNullableByDefault == true
         ? NullabilitySuffix.none
diff --git a/pkg/analyzer/lib/src/summary2/linked_element_builder.dart b/pkg/analyzer/lib/src/summary2/linked_element_builder.dart
deleted file mode 100644
index fcfc0d3..0000000
--- a/pkg/analyzer/lib/src/summary2/linked_element_builder.dart
+++ /dev/null
@@ -1,198 +0,0 @@
-// Copyright (c) 2020, the Dart project authors. Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-import 'package:analyzer/dart/ast/ast.dart';
-import 'package:analyzer/src/dart/ast/ast.dart';
-import 'package:analyzer/src/dart/element/element.dart';
-import 'package:analyzer/src/summary2/linked_unit_context.dart';
-import 'package:analyzer/src/summary2/reference.dart';
-
-class LinkedElementBuilder {
-  final CompilationUnitElementImpl _unitElement;
-  final Reference _classRef;
-  final Reference _enumRef;
-  final Reference _extensionRef;
-  final Reference _functionRef;
-  final Reference _getterRef;
-  final Reference _mixinRef;
-  final Reference _setterRef;
-  final Reference _typeAliasRef;
-  final Reference _variableRef;
-
-  var _nextUnnamedExtensionId = 0;
-
-  LinkedElementBuilder(LinkedUnitContext unitContext)
-      : _unitElement = unitContext.reference.element,
-        _classRef = unitContext.reference.getChild('@class'),
-        _enumRef = unitContext.reference.getChild('@enum'),
-        _extensionRef = unitContext.reference.getChild('@extension'),
-        _functionRef = unitContext.reference.getChild('@function'),
-        _getterRef = unitContext.reference.getChild('@getter'),
-        _mixinRef = unitContext.reference.getChild('@mixin'),
-        _setterRef = unitContext.reference.getChild('@setter'),
-        _typeAliasRef = unitContext.reference.getChild('@typeAlias'),
-        _variableRef = unitContext.reference.getChild('@variable');
-
-  ClassElementImpl classDeclaration(ClassDeclaration node) {
-    var element = node.declaredElement as ClassElementImpl;
-    if (element != null) {
-      return element;
-    }
-
-    var nameNode = node.name;
-    element = ClassElementImpl.forLinkedNode(
-      _unitElement,
-      _classRef.getChild(nameNode.name),
-      node,
-    );
-    nameNode.staticElement = element;
-    return element;
-  }
-
-  ClassElementImpl classTypeAlias(ClassTypeAlias node) {
-    var element = node.declaredElement as ClassElementImpl;
-    if (element != null) {
-      return element;
-    }
-
-    var nameNode = node.name;
-    element = ClassElementImpl.forLinkedNode(
-      _unitElement,
-      _classRef.getChild(nameNode.name),
-      node,
-    );
-    nameNode.staticElement = element;
-    return element;
-  }
-
-  EnumElementImpl enumDeclaration(EnumDeclaration node) {
-    var element = node.declaredElement as EnumElementImpl;
-    if (element != null) {
-      return element;
-    }
-
-    var nameNode = node.name;
-    element = EnumElementImpl.forLinkedNode(
-      _unitElement,
-      _enumRef.getChild(nameNode.name),
-      node,
-    );
-    nameNode.staticElement = element;
-    return element;
-  }
-
-  ExtensionElementImpl extensionDeclaration(ExtensionDeclarationImpl node) {
-    var element = node.declaredElement as ExtensionElementImpl;
-    if (element != null) {
-      return element;
-    }
-
-    var name = node.name?.name;
-    var refName = name ?? 'extension-${_nextUnnamedExtensionId++}';
-    element = ExtensionElementImpl.forLinkedNode(
-      _unitElement,
-      _extensionRef.getChild(refName),
-      node,
-    );
-    node.declaredElement = element;
-    return element;
-  }
-
-  ExecutableElementImpl functionDeclaration(FunctionDeclaration node) {
-    var element = node.declaredElement as ExecutableElementImpl;
-    if (element != null) {
-      return element;
-    }
-
-    var nameNode = node.name;
-    var name = nameNode.name;
-
-    if (node.isGetter) {
-      element = PropertyAccessorElementImpl.forLinkedNode(
-        _unitElement,
-        _getterRef.getChild(name),
-        node,
-      );
-    } else if (node.isSetter) {
-      element = PropertyAccessorElementImpl.forLinkedNode(
-        _unitElement,
-        _setterRef.getChild(name),
-        node,
-      );
-    } else {
-      element = FunctionElementImpl.forLinkedNode(
-        _unitElement,
-        _functionRef.getChild(name),
-        node,
-      );
-    }
-
-    nameNode.staticElement = element;
-    return element;
-  }
-
-  GenericTypeAliasElementImpl functionTypeAlias(FunctionTypeAlias node) {
-    var element = node.declaredElement as GenericTypeAliasElementImpl;
-    if (element != null) {
-      return element;
-    }
-
-    var nameNode = node.name;
-    element = GenericTypeAliasElementImpl.forLinkedNode(
-      _unitElement,
-      _typeAliasRef.getChild(nameNode.name),
-      node,
-    );
-    nameNode.staticElement = element;
-    return element;
-  }
-
-  GenericTypeAliasElementImpl genericTypeAlias(GenericTypeAlias node) {
-    var element = node.declaredElement as GenericTypeAliasElementImpl;
-    if (element != null) {
-      return element;
-    }
-
-    var nameNode = node.name;
-    element = GenericTypeAliasElementImpl.forLinkedNode(
-      _unitElement,
-      _typeAliasRef.getChild(nameNode.name),
-      node,
-    );
-    nameNode.staticElement = element;
-    return element;
-  }
-
-  MixinElementImpl mixinDeclaration(MixinDeclaration node) {
-    var element = node.declaredElement as MixinElementImpl;
-    if (element != null) {
-      return element;
-    }
-
-    var nameNode = node.name;
-    element = MixinElementImpl.forLinkedNode(
-      _unitElement,
-      _mixinRef.getChild(nameNode.name),
-      node,
-    );
-    nameNode.staticElement = element;
-    return element;
-  }
-
-  TopLevelVariableElementImpl topLevelVariable(VariableDeclaration node) {
-    var element = node.declaredElement as TopLevelVariableElementImpl;
-    if (element != null) {
-      return element;
-    }
-
-    var nameNode = node.name;
-    element = TopLevelVariableElementImpl.forLinkedNodeFactory(
-      _unitElement,
-      _variableRef.getChild(nameNode.name),
-      node,
-    );
-    nameNode.staticElement = element;
-    return element;
-  }
-}
diff --git a/pkg/analyzer/lib/src/summary2/linked_element_factory.dart b/pkg/analyzer/lib/src/summary2/linked_element_factory.dart
index b47435a..112fab4 100644
--- a/pkg/analyzer/lib/src/summary2/linked_element_factory.dart
+++ b/pkg/analyzer/lib/src/summary2/linked_element_factory.dart
@@ -337,14 +337,8 @@
       _indexUnitElementDeclarations(unit);
       assert(reference.node != null, '$reference');
     }
-
-    var elementBuilder = unit.linkedContext.elementBuilder;
-    var node = reference.node;
-    if (node is ClassDeclaration) {
-      return elementBuilder.classDeclaration(node);
-    } else {
-      return elementBuilder.classTypeAlias(node);
-    }
+    ClassElementImpl.forLinkedNode(unit, reference, reference.node);
+    return reference.element;
   }
 
   ConstructorElementImpl _constructor(
@@ -420,8 +414,8 @@
       _indexUnitElementDeclarations(unit);
       assert(reference.node != null, '$reference');
     }
-    var elementBuilder = unit.linkedContext.elementBuilder;
-    return elementBuilder.enumDeclaration(reference.node);
+    EnumElementImpl.forLinkedNode(unit, reference, reference.node);
+    return reference.element;
   }
 
   ExtensionElementImpl _extension(
@@ -430,8 +424,8 @@
       _indexUnitElementDeclarations(unit);
       assert(reference.node != null, '$reference');
     }
-    var elementBuilder = unit.linkedContext.elementBuilder;
-    return elementBuilder.extensionDeclaration(reference.node);
+    ExtensionElementImpl.forLinkedNode(unit, reference, reference.node);
+    return reference.element;
   }
 
   FieldElementImpl _field(ClassElementImpl enclosing, Reference reference) {
@@ -473,8 +467,8 @@
       _indexUnitElementDeclarations(unit);
       assert(reference.node != null, '$reference');
     }
-    var elementBuilder = unit.linkedContext.elementBuilder;
-    return elementBuilder.mixinDeclaration(reference.node);
+    MixinElementImpl.forLinkedNode(unit, reference, reference.node);
+    return reference.element;
   }
 
   Element _parameter(ExecutableElementImpl enclosing, Reference reference) {
@@ -497,14 +491,8 @@
       _indexUnitElementDeclarations(unit);
       assert(reference.node != null, '$reference');
     }
-
-    var elementBuilder = unit.linkedContext.elementBuilder;
-    var node = reference.node;
-    if (node is FunctionTypeAlias) {
-      return elementBuilder.functionTypeAlias(node);
-    } else {
-      return elementBuilder.genericTypeAlias(node);
-    }
+    GenericTypeAliasElementImpl.forLinkedNode(unit, reference, reference.node);
+    return reference.element;
   }
 
   /// Index nodes for which we choose to create elements individually,
diff --git a/pkg/analyzer/lib/src/summary2/linked_unit_context.dart b/pkg/analyzer/lib/src/summary2/linked_unit_context.dart
index 73c1f77..24a749f 100644
--- a/pkg/analyzer/lib/src/summary2/linked_unit_context.dart
+++ b/pkg/analyzer/lib/src/summary2/linked_unit_context.dart
@@ -19,7 +19,6 @@
 import 'package:analyzer/src/summary2/ast_binary_reader.dart';
 import 'package:analyzer/src/summary2/lazy_ast.dart';
 import 'package:analyzer/src/summary2/linked_bundle_context.dart';
-import 'package:analyzer/src/summary2/linked_element_builder.dart';
 import 'package:analyzer/src/summary2/reference.dart';
 import 'package:analyzer/src/summary2/type_builder.dart';
 
@@ -39,8 +38,6 @@
 
   AstBinaryReader _astReader;
 
-  LinkedElementBuilder _elementBuilder;
-
   CompilationUnit _unit;
   bool _hasDirectivesRead = false;
 
@@ -69,10 +66,6 @@
     _hasDirectivesRead = _unit != null;
   }
 
-  LinkedElementBuilder get elementBuilder {
-    return _elementBuilder ??= LinkedElementBuilder(this);
-  }
-
   bool get hasPartOfDirective {
     for (var directive in unit_withDirectives.directives) {
       if (directive is PartOfDirective) {
diff --git a/pkg/front_end/lib/src/fasta/kernel/constant_evaluator.dart b/pkg/front_end/lib/src/fasta/kernel/constant_evaluator.dart
index 8618dbe..edb4a54 100644
--- a/pkg/front_end/lib/src/fasta/kernel/constant_evaluator.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/constant_evaluator.dart
@@ -1019,6 +1019,19 @@
   /// As such the return value should be checked (e.g. `is AbortConstant`)
   /// before further use.
   Constant _evaluateSubexpression(Expression node) {
+    if (node is ConstantExpression) {
+      if (node.constant is! UnevaluatedConstant) {
+        // ConstantExpressions just pointing to an actual constant can be
+        // short-circuited. Note that it's accepted instead of just returned to
+        // get canonicalization.
+        return node.accept(this);
+      }
+    } else if (node is BasicLiteral) {
+      // Basic literals (string literals, int literals, double literals,
+      // bool literals and null literals) can be short-circuited too.
+      return node.accept(this);
+    }
+
     bool wasUnevaluated = seenUnevaluatedChild;
     seenUnevaluatedChild = false;
     Constant result;
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 c0d4818..f7492b8 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
@@ -477,12 +477,6 @@
         } else {
           loader.registerStrongOptOutLibrary(this);
         }
-        _languageVersion = new InvalidLanguageVersion(
-            fileUri,
-            _languageVersion.charOffset,
-            _languageVersion.charCount,
-            _languageVersion.isExplicit,
-            loader.target.currentSdkVersion);
       }
     }
     _languageVersion.isFinal = true;
diff --git a/pkg/front_end/lib/src/fasta/type_inference/type_constraint_gatherer.dart b/pkg/front_end/lib/src/fasta/type_inference/type_constraint_gatherer.dart
index 2464c9a..133297c 100644
--- a/pkg/front_end/lib/src/fasta/type_inference/type_constraint_gatherer.dart
+++ b/pkg/front_end/lib/src/fasta/type_inference/type_constraint_gatherer.dart
@@ -296,105 +296,6 @@
     return type == coreTypes.nullType;
   }
 
-  /// Computes [type] as if declared without nullability markers.
-  ///
-  /// The algorithm implemented by [_isNullabilityAwareSubtypeMatch] uses the
-  /// notion of the nullable and the legacy type constructors, that is, int? and
-  /// int* are applications of the nullable and the legacy type constructors to
-  /// type int correspondingly.  The algorithm requires the ability to peel off
-  /// the two type constructors from the underlying types, which is done by
-  /// [_computeRawType].
-  DartType _computeRawType(DartType type) {
-    if (type is TypeParameterType) {
-      if (type.promotedBound == null) {
-        // The default nullability for library is used when there are no
-        // nullability markers on the type.
-        return new TypeParameterType.withDefaultNullabilityForLibrary(
-            type.parameter, _currentLibrary);
-      } else {
-        // Intersection types can't be arguments to the nullable and the legacy
-        // type constructors, so nothing can be peeled off.
-        return type;
-      }
-    } else if (type == coreTypes.nullType) {
-      return type;
-    } else {
-      // For most types, peeling off the nullability constructors means that
-      // they become non-nullable.
-      return type.withDeclaredNullability(Nullability.nonNullable);
-    }
-  }
-
-  /// Returns true if [type] is declared without nullability markers.
-  ///
-  /// The algorithm implemented by [_isNullabilityAwareSubtypeMatch] uses the
-  /// notion of the nullable and the legacy type constructors, that is, int? and
-  /// int* are applications of the nullable and the legacy type constructors to
-  /// type int correspondingly.  The algorithm requires the ability to detect if
-  /// a type is raw, that is, if it is declared without any of the two
-  /// constructors.  Method [_isRawTypeParameterType] implements that check for
-  /// [TypeParameterType]s.  For most types, comparing their
-  /// [DartType.declaredNullability] is enough, but the case of
-  /// [TypeParameterType]s is more complex for two reasons: (1) intersection
-  /// types are encoded as [TypeParameterType]s, and they can't be arguments of
-  /// the nullability constructors, and (2) if a [TypeParameterType] is declared
-  /// raw, its semantic nullability can be anything from
-  /// [Nullability.nonNullable], [Nullability.undetermined], and
-  /// [Nullability.legacy], depending on the bound.  [_isRawTypeParameterType]
-  /// checks if [type] has the same nullability as if it was declared without
-  /// any nullability markers by the programmer.
-  bool _isRawTypeParameterType(TypeParameterType type) {
-    // The default nullability for library is used when there are no nullability
-    // markers on the type.
-    return type.promotedBound == null &&
-        type.declaredNullability ==
-            new TypeParameterType.withDefaultNullabilityForLibrary(
-                    type.parameter, _currentLibrary)
-                .declaredNullability;
-  }
-
-  /// Returns true if [type] is an application of the nullable type constructor.
-  ///
-  /// The algorithm implemented by [_isNullabilityAwareSubtypeMatch] uses the
-  /// notion of the nullable type constructor, that is, int? is an application
-  /// of the nullable type constructor to type int.  The algorithm requires the
-  /// ability to detect if a type is an application of the nullable constructor
-  /// to another type, which is done by [_isNullableTypeConstructorApplication].
-  bool _isNullableTypeConstructorApplication(DartType type) {
-    return type.declaredNullability == Nullability.nullable &&
-        type is! DynamicType &&
-        type is! VoidType &&
-        type != coreTypes.nullType;
-  }
-
-  /// Returns true if [type] is an application of the legacy type constructor.
-  ///
-  /// The algorithm implemented by [_isNullabilityAwareSubtypeMatch] uses the
-  /// notion of the legacy type constructor, that is, int* is an application of
-  /// the legacy type constructor to type int.  The algorithm requires the
-  /// ability to detect if a type is an application of the nullable constructor
-  /// to another type, which is done by [_isNullableTypeConstructorApplication].
-  bool _isLegacyTypeConstructorApplication(DartType type) {
-    if (type is TypeParameterType) {
-      if (type.promotedBound == null) {
-        // The legacy nullability is considered an application of the legacy
-        // nullability constructor if it doesn't match the default nullability
-        // of the type-parameter type for the library.
-        return type.declaredNullability == Nullability.legacy &&
-            type.declaredNullability !=
-                new TypeParameterType.withDefaultNullabilityForLibrary(
-                        type.parameter, _currentLibrary)
-                    .declaredNullability;
-      } else {
-        return false;
-      }
-    } else if (type is InvalidType) {
-      return false;
-    } else {
-      return type.declaredNullability == Nullability.legacy;
-    }
-  }
-
   /// Matches [p] against [q] as a subtype against supertype.
   ///
   /// Returns true if [p] is a subtype of [q] under some constraints, and false
@@ -473,7 +374,7 @@
     //
     // Under constraint _ <: X <: Q.
     if (p is TypeParameterType &&
-        _isRawTypeParameterType(p) &&
+        isTypeParameterTypeWithoutNullabilityMarker(p, _currentLibrary) &&
         _parametersToConstrain.contains(p.parameter)) {
       _constrainParameterUpper(p.parameter, q);
       return true;
@@ -483,7 +384,7 @@
     //
     // Under constraint P <: X <: _.
     if (q is TypeParameterType &&
-        _isRawTypeParameterType(q) &&
+        isTypeParameterTypeWithoutNullabilityMarker(q, _currentLibrary) &&
         _parametersToConstrain.contains(q.parameter)) {
       _constrainParameterLower(q.parameter, p);
       return true;
@@ -502,8 +403,11 @@
     // If P is a legacy type P0* then the match holds under constraint set C:
     //
     // Only if P0 is a subtype match for Q under constraint set C.
-    if (_isLegacyTypeConstructorApplication(p)) {
-      return _isNullabilityAwareSubtypeMatch(_computeRawType(p), q,
+    if (isLegacyTypeConstructorApplication(p, _currentLibrary)) {
+      return _isNullabilityAwareSubtypeMatch(
+          computeTypeWithoutNullabilityMarker(p, _currentLibrary,
+              nullType: coreTypes.nullType),
+          q,
           constrainSupertype: constrainSupertype);
     }
 
@@ -513,11 +417,14 @@
     // set C.
     // Or if P is not dynamic or void and P is a subtype match for Q0? under
     // constraint set C.
-    if (_isLegacyTypeConstructorApplication(q)) {
+    if (isLegacyTypeConstructorApplication(q, _currentLibrary)) {
       final int baseConstraintCount = _protoConstraints.length;
 
       if ((p is DynamicType || p is VoidType) &&
-          _isNullabilityAwareSubtypeMatch(p, _computeRawType(q),
+          _isNullabilityAwareSubtypeMatch(
+              p,
+              computeTypeWithoutNullabilityMarker(q, _currentLibrary,
+                  nullType: coreTypes.nullType),
               constrainSupertype: constrainSupertype)) {
         return true;
       }
@@ -580,12 +487,17 @@
     // Or if P is a subtype match for Q0 under non-empty constraint set C.
     // Or if P is a subtype match for Null under constraint set C.
     // Or if P is a subtype match for Q0 under empty constraint set C.
-    if (_isNullableTypeConstructorApplication(q)) {
+    if (isNullableTypeConstructorApplication(q, nullType: coreTypes.nullType)) {
       final int baseConstraintCount = _protoConstraints.length;
-      final DartType rawP = _computeRawType(p);
-      final DartType rawQ = _computeRawType(q);
+      final DartType rawP = computeTypeWithoutNullabilityMarker(
+          p, _currentLibrary,
+          nullType: coreTypes.nullType);
+      final DartType rawQ = computeTypeWithoutNullabilityMarker(
+          q, _currentLibrary,
+          nullType: coreTypes.nullType);
 
-      if (_isNullableTypeConstructorApplication(p) &&
+      if (isNullableTypeConstructorApplication(p,
+              nullType: coreTypes.nullType) &&
           _isNullabilityAwareSubtypeMatch(rawP, rawQ,
               constrainSupertype: constrainSupertype)) {
         return true;
@@ -641,9 +553,12 @@
     //
     // If P0 is a subtype match for Q under constraint set C1.
     // And if Null is a subtype match for Q under constraint set C2.
-    if (_isNullableTypeConstructorApplication(p)) {
+    if (isNullableTypeConstructorApplication(p, nullType: coreTypes.nullType)) {
       final int baseConstraintCount = _protoConstraints.length;
-      if (_isNullabilityAwareSubtypeMatch(_computeRawType(p), q,
+      if (_isNullabilityAwareSubtypeMatch(
+              computeTypeWithoutNullabilityMarker(p, _currentLibrary,
+                  nullType: coreTypes.nullType),
+              q,
               constrainSupertype: constrainSupertype) &&
           _isNullabilityAwareSubtypeMatch(coreTypes.nullType, q,
               constrainSupertype: constrainSupertype)) {
diff --git a/pkg/front_end/test/spell_checking_list_code.txt b/pkg/front_end/test/spell_checking_list_code.txt
index 16c406d..cd83c1b 100644
--- a/pkg/front_end/test/spell_checking_list_code.txt
+++ b/pkg/front_end/test/spell_checking_list_code.txt
@@ -165,6 +165,7 @@
 checkpoint
 chunks
 ci
+circuited
 ck
 cl
 claim
diff --git a/pkg/front_end/test/spell_checking_list_common.txt b/pkg/front_end/test/spell_checking_list_common.txt
index 267154d..267dd7a 100644
--- a/pkg/front_end/test/spell_checking_list_common.txt
+++ b/pkg/front_end/test/spell_checking_list_common.txt
@@ -1069,6 +1069,7 @@
 executes
 executing
 execution
+exempt
 exercise
 exhaustive
 exist
@@ -2130,6 +2131,7 @@
 peel
 peeled
 peeling
+peels
 pending
 percent
 percolate
diff --git a/pkg/front_end/testcases/general/main_declaration.dart b/pkg/front_end/testcases/general/main_declaration.dart
new file mode 100644
index 0000000..e4df1b0
--- /dev/null
+++ b/pkg/front_end/testcases/general/main_declaration.dart
@@ -0,0 +1,7 @@
+// Copyright (c) 2020, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'main_declaration_lib.dart';
+
+main() {}
diff --git a/pkg/front_end/testcases/general/main_declaration.dart.outline.expect b/pkg/front_end/testcases/general/main_declaration.dart.outline.expect
new file mode 100644
index 0000000..600a236
--- /dev/null
+++ b/pkg/front_end/testcases/general/main_declaration.dart.outline.expect
@@ -0,0 +1,14 @@
+library;
+import self as self;
+
+import "org-dartlang-testcase:///main_declaration_lib.dart";
+
+static method main() → dynamic
+  ;
+
+library;
+import self as self2;
+import "dart:core" as core;
+
+static method main(core::String* args) → dynamic
+  ;
diff --git a/pkg/front_end/testcases/general/main_declaration.dart.strong.expect b/pkg/front_end/testcases/general/main_declaration.dart.strong.expect
new file mode 100644
index 0000000..58118e1
--- /dev/null
+++ b/pkg/front_end/testcases/general/main_declaration.dart.strong.expect
@@ -0,0 +1,12 @@
+library;
+import self as self;
+
+import "org-dartlang-testcase:///main_declaration_lib.dart";
+
+static method main() → dynamic {}
+
+library;
+import self as self2;
+import "dart:core" as core;
+
+static method main(core::String* args) → dynamic {}
diff --git a/pkg/front_end/testcases/general/main_declaration.dart.strong.transformed.expect b/pkg/front_end/testcases/general/main_declaration.dart.strong.transformed.expect
new file mode 100644
index 0000000..58118e1
--- /dev/null
+++ b/pkg/front_end/testcases/general/main_declaration.dart.strong.transformed.expect
@@ -0,0 +1,12 @@
+library;
+import self as self;
+
+import "org-dartlang-testcase:///main_declaration_lib.dart";
+
+static method main() → dynamic {}
+
+library;
+import self as self2;
+import "dart:core" as core;
+
+static method main(core::String* args) → dynamic {}
diff --git a/pkg/front_end/testcases/general/main_declaration.dart.textual_outline.expect b/pkg/front_end/testcases/general/main_declaration.dart.textual_outline.expect
new file mode 100644
index 0000000..5ab8783
--- /dev/null
+++ b/pkg/front_end/testcases/general/main_declaration.dart.textual_outline.expect
@@ -0,0 +1,3 @@
+import 'main_declaration_lib.dart';
+
+main() {}
diff --git a/pkg/front_end/testcases/general/main_declaration.dart.textual_outline_modelled.expect b/pkg/front_end/testcases/general/main_declaration.dart.textual_outline_modelled.expect
new file mode 100644
index 0000000..5ab8783
--- /dev/null
+++ b/pkg/front_end/testcases/general/main_declaration.dart.textual_outline_modelled.expect
@@ -0,0 +1,3 @@
+import 'main_declaration_lib.dart';
+
+main() {}
diff --git a/pkg/front_end/testcases/general/main_declaration_lib.dart b/pkg/front_end/testcases/general/main_declaration_lib.dart
new file mode 100644
index 0000000..f0d8fb7
--- /dev/null
+++ b/pkg/front_end/testcases/general/main_declaration_lib.dart
@@ -0,0 +1,6 @@
+// Copyright (c) 2020, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// This would be an invalid main declaration in a null safe library.
+main(String args) {}
diff --git a/pkg/front_end/testcases/late_lowering/initializer_rewrite_from_opt_out.dart.outline.expect b/pkg/front_end/testcases/late_lowering/initializer_rewrite_from_opt_out.dart.outline.expect
index 7ddeb49..db00c38 100644
--- a/pkg/front_end/testcases/late_lowering/initializer_rewrite_from_opt_out.dart.outline.expect
+++ b/pkg/front_end/testcases/late_lowering/initializer_rewrite_from_opt_out.dart.outline.expect
@@ -34,7 +34,7 @@
 static method throws(() → dynamic f, core::String message) → dynamic
   ;
 
-library /*isNonNullableByDefault*/;
+library;
 //
 // Problems in library:
 //
@@ -45,5 +45,5 @@
 import self as self2;
 import "dart:core" as core;
 
-static method computeInitialValue() → core::int
+static method computeInitialValue() → core::int*
   ;
diff --git a/pkg/front_end/testcases/late_lowering/initializer_rewrite_from_opt_out.dart.strong.expect b/pkg/front_end/testcases/late_lowering/initializer_rewrite_from_opt_out.dart.strong.expect
index 2a73d8e..cc020ed 100644
--- a/pkg/front_end/testcases/late_lowering/initializer_rewrite_from_opt_out.dart.strong.expect
+++ b/pkg/front_end/testcases/late_lowering/initializer_rewrite_from_opt_out.dart.strong.expect
@@ -21,7 +21,7 @@
     : super core::Object::•()
     ;
   static get nonNullableStaticField() → core::int
-    return let final core::int? #t1 = self::Class::_#nonNullableStaticField in #t1.==(null) ?{core::int} let final core::int #t2 = (let final core::int #t3 = self::Class::nonNullableStaticFieldReads in let final core::int #t4 = self::Class::nonNullableStaticFieldReads = #t3.{core::num::+}(1) in #t3).{core::num::==}(0) ?{core::int} self::Class::nonNullableStaticField : ini::computeInitialValue() in self::Class::_#nonNullableStaticField.==(null) ?{core::int} self::Class::_#nonNullableStaticField = #t2 : throw new _in::LateInitializationErrorImpl::•("Field 'nonNullableStaticField' has been assigned during initialization.") : #t1{core::int};
+    return let final core::int? #t1 = self::Class::_#nonNullableStaticField in #t1.==(null) ?{core::int} let final core::int #t2 = (let final core::int #t3 = self::Class::nonNullableStaticFieldReads in let final core::int #t4 = self::Class::nonNullableStaticFieldReads = #t3.{core::num::+}(1) in #t3).{core::num::==}(0) ?{core::int*} self::Class::nonNullableStaticField : ini::computeInitialValue() in self::Class::_#nonNullableStaticField.==(null) ?{core::int} self::Class::_#nonNullableStaticField = #t2 : throw new _in::LateInitializationErrorImpl::•("Field 'nonNullableStaticField' has been assigned during initialization.") : #t1{core::int};
   static get nullableStaticField() → core::int? {
     if(!self::Class::_#nullableStaticField#isSet) {
       final core::int? #t5 = (let final core::int #t6 = self::Class::nullableStaticFieldReads in let final core::int #t7 = self::Class::nullableStaticFieldReads = #t6.{core::num::+}(1) in #t6).{core::num::==}(0) ?{core::int?} self::Class::nullableStaticField : ini::computeInitialValue();
@@ -33,7 +33,7 @@
     return self::Class::_#nullableStaticField;
   }
   get nonNullableInstanceField() → core::int
-    return let final core::int? #t8 = this.{self::Class::_#Class#nonNullableInstanceField} in #t8.==(null) ?{core::int} let final core::int #t9 = (let final core::int #t10 = this.{self::Class::nonNullableInstanceFieldReads} in let final core::int #t11 = this.{self::Class::nonNullableInstanceFieldReads} = #t10.{core::num::+}(1) in #t10).{core::num::==}(0) ?{core::int} this.{self::Class::nonNullableInstanceField} : ini::computeInitialValue() in this.{self::Class::_#Class#nonNullableInstanceField}.==(null) ?{core::int} this.{self::Class::_#Class#nonNullableInstanceField} = #t9 : throw new _in::LateInitializationErrorImpl::•("Field 'nonNullableInstanceField' has been assigned during initialization.") : #t8{core::int};
+    return let final core::int? #t8 = this.{self::Class::_#Class#nonNullableInstanceField} in #t8.==(null) ?{core::int} let final core::int #t9 = (let final core::int #t10 = this.{self::Class::nonNullableInstanceFieldReads} in let final core::int #t11 = this.{self::Class::nonNullableInstanceFieldReads} = #t10.{core::num::+}(1) in #t10).{core::num::==}(0) ?{core::int*} this.{self::Class::nonNullableInstanceField} : ini::computeInitialValue() in this.{self::Class::_#Class#nonNullableInstanceField}.==(null) ?{core::int} this.{self::Class::_#Class#nonNullableInstanceField} = #t9 : throw new _in::LateInitializationErrorImpl::•("Field 'nonNullableInstanceField' has been assigned during initialization.") : #t8{core::int};
   get nullableInstanceField() → core::int? {
     if(!this.{self::Class::_#Class#nullableInstanceField#isSet}) {
       final core::int? #t12 = (let final core::int #t13 = this.{self::Class::nullableInstanceFieldReads} in let final core::int #t14 = this.{self::Class::nullableInstanceFieldReads} = #t13.{core::num::+}(1) in #t13).{core::num::==}(0) ?{core::int?} this.{self::Class::nullableInstanceField} : ini::computeInitialValue();
@@ -51,7 +51,7 @@
 static field core::int? _#nullableTopLevelField = null;
 static field core::bool _#nullableTopLevelField#isSet = false;
 static get nonNullableTopLevelField() → core::int
-  return let final core::int? #t15 = self::_#nonNullableTopLevelField in #t15.==(null) ?{core::int} let final core::int #t16 = (let final core::int #t17 = self::nonNullableTopLevelFieldReads in let final core::int #t18 = self::nonNullableTopLevelFieldReads = #t17.{core::num::+}(1) in #t17).{core::num::==}(0) ?{core::int} self::nonNullableTopLevelField : ini::computeInitialValue() in self::_#nonNullableTopLevelField.==(null) ?{core::int} self::_#nonNullableTopLevelField = #t16 : throw new _in::LateInitializationErrorImpl::•("Field 'nonNullableTopLevelField' has been assigned during initialization.") : #t15{core::int};
+  return let final core::int? #t15 = self::_#nonNullableTopLevelField in #t15.==(null) ?{core::int} let final core::int #t16 = (let final core::int #t17 = self::nonNullableTopLevelFieldReads in let final core::int #t18 = self::nonNullableTopLevelFieldReads = #t17.{core::num::+}(1) in #t17).{core::num::==}(0) ?{core::int*} self::nonNullableTopLevelField : ini::computeInitialValue() in self::_#nonNullableTopLevelField.==(null) ?{core::int} self::_#nonNullableTopLevelField = #t16 : throw new _in::LateInitializationErrorImpl::•("Field 'nonNullableTopLevelField' has been assigned during initialization.") : #t15{core::int};
 static get nullableTopLevelField() → core::int? {
   if(!self::_#nullableTopLevelField#isSet) {
     final core::int? #t19 = (let final core::int #t20 = self::nullableTopLevelFieldReads in let final core::int #t21 = self::nullableTopLevelFieldReads = #t20.{core::num::+}(1) in #t20).{core::num::==}(0) ?{core::int?} self::nullableTopLevelField : ini::computeInitialValue();
@@ -82,7 +82,7 @@
   throw "${message}: ${value}";
 }
 
-library /*isNonNullableByDefault*/;
+library;
 //
 // Problems in library:
 //
@@ -90,14 +90,8 @@
 // // @dart=2.8
 // ^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/late_lowering/initializer_rewrite_from_opt_out_lib.dart:7:30: Error: A value of type 'Null' can't be returned from a function with return type 'int'.
-// int computeInitialValue() => null;
-//                              ^
-//
 import self as ini;
 import "dart:core" as core;
 
-static method computeInitialValue() → core::int
-  return let final<BottomType> #t22 = invalid-expression "pkg/front_end/testcases/late_lowering/initializer_rewrite_from_opt_out_lib.dart:7:30: Error: A value of type 'Null' can't be returned from a function with return type 'int'.
-int computeInitialValue() => null;
-                             ^" in null as{TypeError,ForNonNullableByDefault} core::int;
+static method computeInitialValue() → core::int*
+  return null;
diff --git a/pkg/front_end/testcases/late_lowering/initializer_rewrite_from_opt_out.dart.strong.transformed.expect b/pkg/front_end/testcases/late_lowering/initializer_rewrite_from_opt_out.dart.strong.transformed.expect
index 9c70f2f..cc020ed 100644
--- a/pkg/front_end/testcases/late_lowering/initializer_rewrite_from_opt_out.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/late_lowering/initializer_rewrite_from_opt_out.dart.strong.transformed.expect
@@ -21,7 +21,7 @@
     : super core::Object::•()
     ;
   static get nonNullableStaticField() → core::int
-    return let final core::int? #t1 = self::Class::_#nonNullableStaticField in #t1.==(null) ?{core::int} let final core::int #t2 = (let final core::int #t3 = self::Class::nonNullableStaticFieldReads in let final core::int #t4 = self::Class::nonNullableStaticFieldReads = #t3.{core::num::+}(1) in #t3).{core::num::==}(0) ?{core::int} self::Class::nonNullableStaticField : ini::computeInitialValue() in self::Class::_#nonNullableStaticField.==(null) ?{core::int} self::Class::_#nonNullableStaticField = #t2 : throw new _in::LateInitializationErrorImpl::•("Field 'nonNullableStaticField' has been assigned during initialization.") : #t1{core::int};
+    return let final core::int? #t1 = self::Class::_#nonNullableStaticField in #t1.==(null) ?{core::int} let final core::int #t2 = (let final core::int #t3 = self::Class::nonNullableStaticFieldReads in let final core::int #t4 = self::Class::nonNullableStaticFieldReads = #t3.{core::num::+}(1) in #t3).{core::num::==}(0) ?{core::int*} self::Class::nonNullableStaticField : ini::computeInitialValue() in self::Class::_#nonNullableStaticField.==(null) ?{core::int} self::Class::_#nonNullableStaticField = #t2 : throw new _in::LateInitializationErrorImpl::•("Field 'nonNullableStaticField' has been assigned during initialization.") : #t1{core::int};
   static get nullableStaticField() → core::int? {
     if(!self::Class::_#nullableStaticField#isSet) {
       final core::int? #t5 = (let final core::int #t6 = self::Class::nullableStaticFieldReads in let final core::int #t7 = self::Class::nullableStaticFieldReads = #t6.{core::num::+}(1) in #t6).{core::num::==}(0) ?{core::int?} self::Class::nullableStaticField : ini::computeInitialValue();
@@ -33,7 +33,7 @@
     return self::Class::_#nullableStaticField;
   }
   get nonNullableInstanceField() → core::int
-    return let final core::int? #t8 = this.{self::Class::_#Class#nonNullableInstanceField} in #t8.==(null) ?{core::int} let final core::int #t9 = (let final core::int #t10 = this.{self::Class::nonNullableInstanceFieldReads} in let final core::int #t11 = this.{self::Class::nonNullableInstanceFieldReads} = #t10.{core::num::+}(1) in #t10).{core::num::==}(0) ?{core::int} this.{self::Class::nonNullableInstanceField} : ini::computeInitialValue() in this.{self::Class::_#Class#nonNullableInstanceField}.==(null) ?{core::int} this.{self::Class::_#Class#nonNullableInstanceField} = #t9 : throw new _in::LateInitializationErrorImpl::•("Field 'nonNullableInstanceField' has been assigned during initialization.") : #t8{core::int};
+    return let final core::int? #t8 = this.{self::Class::_#Class#nonNullableInstanceField} in #t8.==(null) ?{core::int} let final core::int #t9 = (let final core::int #t10 = this.{self::Class::nonNullableInstanceFieldReads} in let final core::int #t11 = this.{self::Class::nonNullableInstanceFieldReads} = #t10.{core::num::+}(1) in #t10).{core::num::==}(0) ?{core::int*} this.{self::Class::nonNullableInstanceField} : ini::computeInitialValue() in this.{self::Class::_#Class#nonNullableInstanceField}.==(null) ?{core::int} this.{self::Class::_#Class#nonNullableInstanceField} = #t9 : throw new _in::LateInitializationErrorImpl::•("Field 'nonNullableInstanceField' has been assigned during initialization.") : #t8{core::int};
   get nullableInstanceField() → core::int? {
     if(!this.{self::Class::_#Class#nullableInstanceField#isSet}) {
       final core::int? #t12 = (let final core::int #t13 = this.{self::Class::nullableInstanceFieldReads} in let final core::int #t14 = this.{self::Class::nullableInstanceFieldReads} = #t13.{core::num::+}(1) in #t13).{core::num::==}(0) ?{core::int?} this.{self::Class::nullableInstanceField} : ini::computeInitialValue();
@@ -51,7 +51,7 @@
 static field core::int? _#nullableTopLevelField = null;
 static field core::bool _#nullableTopLevelField#isSet = false;
 static get nonNullableTopLevelField() → core::int
-  return let final core::int? #t15 = self::_#nonNullableTopLevelField in #t15.==(null) ?{core::int} let final core::int #t16 = (let final core::int #t17 = self::nonNullableTopLevelFieldReads in let final core::int #t18 = self::nonNullableTopLevelFieldReads = #t17.{core::num::+}(1) in #t17).{core::num::==}(0) ?{core::int} self::nonNullableTopLevelField : ini::computeInitialValue() in self::_#nonNullableTopLevelField.==(null) ?{core::int} self::_#nonNullableTopLevelField = #t16 : throw new _in::LateInitializationErrorImpl::•("Field 'nonNullableTopLevelField' has been assigned during initialization.") : #t15{core::int};
+  return let final core::int? #t15 = self::_#nonNullableTopLevelField in #t15.==(null) ?{core::int} let final core::int #t16 = (let final core::int #t17 = self::nonNullableTopLevelFieldReads in let final core::int #t18 = self::nonNullableTopLevelFieldReads = #t17.{core::num::+}(1) in #t17).{core::num::==}(0) ?{core::int*} self::nonNullableTopLevelField : ini::computeInitialValue() in self::_#nonNullableTopLevelField.==(null) ?{core::int} self::_#nonNullableTopLevelField = #t16 : throw new _in::LateInitializationErrorImpl::•("Field 'nonNullableTopLevelField' has been assigned during initialization.") : #t15{core::int};
 static get nullableTopLevelField() → core::int? {
   if(!self::_#nullableTopLevelField#isSet) {
     final core::int? #t19 = (let final core::int #t20 = self::nullableTopLevelFieldReads in let final core::int #t21 = self::nullableTopLevelFieldReads = #t20.{core::num::+}(1) in #t20).{core::num::==}(0) ?{core::int?} self::nullableTopLevelField : ini::computeInitialValue();
@@ -82,7 +82,7 @@
   throw "${message}: ${value}";
 }
 
-library /*isNonNullableByDefault*/;
+library;
 //
 // Problems in library:
 //
@@ -90,21 +90,8 @@
 // // @dart=2.8
 // ^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/late_lowering/initializer_rewrite_from_opt_out_lib.dart:7:30: Error: A value of type 'Null' can't be returned from a function with return type 'int'.
-// int computeInitialValue() => null;
-//                              ^
-//
 import self as ini;
 import "dart:core" as core;
 
-static method computeInitialValue() → core::int
-  return let final<BottomType> #t22 = invalid-expression "pkg/front_end/testcases/late_lowering/initializer_rewrite_from_opt_out_lib.dart:7:30: Error: A value of type 'Null' can't be returned from a function with return type 'int'.
-int computeInitialValue() => null;
-                             ^" in let core::Null? #t23 = null in #t23.==(null) ?{core::int} #t23 as{TypeError,ForNonNullableByDefault} core::int : #t23{core::int};
-
-
-Extra constant evaluation status:
-Evaluated: MethodInvocation @ org-dartlang-testcase:///initializer_rewrite_from_opt_out_lib.dart:7:30 -> BoolConstant(true)
-Evaluated: VariableGet @ org-dartlang-testcase:///initializer_rewrite_from_opt_out_lib.dart:7:30 -> NullConstant(null)
-Evaluated: VariableGet @ org-dartlang-testcase:///initializer_rewrite_from_opt_out_lib.dart:7:30 -> NullConstant(null)
-Extra constant evaluation: evaluated: 185, effectively constant: 3
+static method computeInitialValue() → core::int*
+  return null;
diff --git a/pkg/front_end/testcases/late_lowering/non_nullable_from_opt_out.dart.outline.expect b/pkg/front_end/testcases/late_lowering/non_nullable_from_opt_out.dart.outline.expect
index edaef86..8fc95bd 100644
--- a/pkg/front_end/testcases/late_lowering/non_nullable_from_opt_out.dart.outline.expect
+++ b/pkg/front_end/testcases/late_lowering/non_nullable_from_opt_out.dart.outline.expect
@@ -1,4 +1,4 @@
-library /*isNonNullableByDefault*/;
+library;
 //
 // Problems in library:
 //
diff --git a/pkg/front_end/testcases/late_lowering/non_nullable_from_opt_out.dart.strong.expect b/pkg/front_end/testcases/late_lowering/non_nullable_from_opt_out.dart.strong.expect
index 3e34630..6ffbd4b 100644
--- a/pkg/front_end/testcases/late_lowering/non_nullable_from_opt_out.dart.strong.expect
+++ b/pkg/front_end/testcases/late_lowering/non_nullable_from_opt_out.dart.strong.expect
@@ -1,4 +1,4 @@
-library /*isNonNullableByDefault*/;
+library;
 //
 // Problems in library:
 //
@@ -6,43 +6,6 @@
 // // @dart=2.8
 // ^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/late_lowering/non_nullable_from_opt_out.dart:10:19: Error: A value of type 'Null' can't be assigned to a variable of type 'int'.
-//   topLevelField = null;
-//                   ^
-//
-// pkg/front_end/testcases/late_lowering/non_nullable_from_opt_out.dart:14:21: Error: A value of type 'Null' can't be assigned to a variable of type 'int'.
-//   c.instanceField = null;
-//                     ^
-//
-// pkg/front_end/testcases/late_lowering/non_nullable_from_opt_out.dart:16:28: Error: A value of type 'Null' can't be assigned to a variable of type 'int'.
-//   c.instanceTypeVariable = null;
-//                            ^
-//
-// pkg/front_end/testcases/late_lowering/non_nullable_from_opt_out.dart:17:33: Error: A value of type 'Null' can't be assigned to a variable of type 'int'.
-//   c.finalInstanceTypeVariable = null;
-//                                 ^
-//
-// pkg/front_end/testcases/late_lowering/non_nullable_from_opt_out.dart:19:23: Error: A value of type 'Null' can't be assigned to a variable of type 'int'.
-//   Class.staticField = null;
-//                       ^
-//
-// pkg/front_end/testcases/late_lowering/non_nullable_from_opt_out.dart:33:46: Error: A value of type 'Null' can't be assigned to a variable of type 'int'.
-//   throws(() => c.finalInstanceTypeVariable = null);
-//                                              ^
-//
-// pkg/front_end/testcases/late_lowering/non_nullable_from_opt_out.dart:36:16: Error: The argument type 'Null' can't be assigned to the parameter type 'int'.
-//   method(true, null, null);
-//                ^
-//
-// pkg/front_end/testcases/late_lowering/non_nullable_from_opt_out.dart:36:3: Error: Inferred type argument 'Null' doesn't conform to the bound 'Object' of the type variable 'T' on 'method'.
-//  - 'Object' is from 'dart:core'.
-// Try specifying type arguments explicitly so that they conform to the bounds.
-//   method(true, null, null);
-//   ^
-// pkg/front_end/testcases/late_lowering/non_nullable_from_opt_out_lib.dart:18:8: Context: This is the type variable whose bound isn't conformed to.
-// method<T extends Object>(bool b, int i, T t) {
-//        ^
-//
 import self as self;
 import "non_nullable_from_opt_out_lib.dart" as non;
 import "dart:core" as core;
@@ -50,24 +13,14 @@
 import "org-dartlang-testcase:///non_nullable_from_opt_out_lib.dart";
 
 static method main() → dynamic {
-  non::topLevelField = let final<BottomType> #t1 = invalid-expression "pkg/front_end/testcases/late_lowering/non_nullable_from_opt_out.dart:10:19: Error: A value of type 'Null' can't be assigned to a variable of type 'int'.
-  topLevelField = null;
-                  ^" in null as{TypeError,ForNonNullableByDefault} core::int;
+  non::topLevelField = null;
   non::finalTopLevelField = null;
-  non::Class<core::int> c = new non::Class::•<core::int>();
-  c.{non::Class::instanceField} = let final<BottomType> #t2 = invalid-expression "pkg/front_end/testcases/late_lowering/non_nullable_from_opt_out.dart:14:21: Error: A value of type 'Null' can't be assigned to a variable of type 'int'.
-  c.instanceField = null;
-                    ^" in null as{TypeError,ForNonNullableByDefault} core::int;
+  non::Class<core::int*>* c = new non::Class::•<core::int*>();
+  c.{non::Class::instanceField} = null;
   c.{non::Class::finalInstanceField} = null;
-  c.{non::Class::instanceTypeVariable} = let final<BottomType> #t3 = invalid-expression "pkg/front_end/testcases/late_lowering/non_nullable_from_opt_out.dart:16:28: Error: A value of type 'Null' can't be assigned to a variable of type 'int'.
-  c.instanceTypeVariable = null;
-                           ^" in null as{TypeError,ForNonNullableByDefault} core::int;
-  c.{non::Class::finalInstanceTypeVariable} = let final<BottomType> #t4 = invalid-expression "pkg/front_end/testcases/late_lowering/non_nullable_from_opt_out.dart:17:33: Error: A value of type 'Null' can't be assigned to a variable of type 'int'.
-  c.finalInstanceTypeVariable = null;
-                                ^" in null as{TypeError,ForNonNullableByDefault} core::int;
-  non::Class::staticField = let final<BottomType> #t5 = invalid-expression "pkg/front_end/testcases/late_lowering/non_nullable_from_opt_out.dart:19:23: Error: A value of type 'Null' can't be assigned to a variable of type 'int'.
-  Class.staticField = null;
-                      ^" in null as{TypeError,ForNonNullableByDefault} core::int;
+  c.{non::Class::instanceTypeVariable} = null;
+  c.{non::Class::finalInstanceTypeVariable} = null;
+  non::Class::staticField = null;
   non::Class::staticFinalField = null;
   non::expect(null, non::topLevelField);
   non::expect(null, non::finalTopLevelField);
@@ -79,13 +32,9 @@
   non::expect(null, non::Class::staticFinalField);
   non::throws(() → core::Null? => non::finalTopLevelField = null);
   non::throws(() → core::Null? => c.{non::Class::finalInstanceField} = null);
-  non::throws(() → core::Null? => c.{non::Class::finalInstanceTypeVariable} = let final<BottomType> #t6 = invalid-expression "pkg/front_end/testcases/late_lowering/non_nullable_from_opt_out.dart:33:46: Error: A value of type 'Null' can't be assigned to a variable of type 'int'.
-  throws(() => c.finalInstanceTypeVariable = null);
-                                             ^" in null as{TypeError,ForNonNullableByDefault} core::int);
+  non::throws(() → core::Null? => c.{non::Class::finalInstanceTypeVariable} = null);
   non::throws(() → core::Null? => non::Class::staticFinalField = null);
-  non::method<core::Null?>(true, let final<BottomType> #t7 = invalid-expression "pkg/front_end/testcases/late_lowering/non_nullable_from_opt_out.dart:36:16: Error: The argument type 'Null' can't be assigned to the parameter type 'int'.
-  method(true, null, null);
-               ^" in null as{TypeError,ForNonNullableByDefault} core::int, null);
+  non::method<core::Null?>(true, null, null);
 }
 
 library /*isNonNullableByDefault*/;
@@ -106,87 +55,87 @@
     : super core::Object::•()
     ;
   get instanceField() → core::int
-    return let final core::int? #t8 = this.{non::Class::_#Class#instanceField} in #t8.==(null) ?{core::int} throw new _in::LateInitializationErrorImpl::•("Field 'instanceField' has not been initialized.") : #t8{core::int};
-  set instanceField(core::int #t9) → void
-    this.{non::Class::_#Class#instanceField} = #t9;
+    return let final core::int? #t1 = this.{non::Class::_#Class#instanceField} in #t1.==(null) ?{core::int} throw new _in::LateInitializationErrorImpl::•("Field 'instanceField' has not been initialized.") : #t1{core::int};
+  set instanceField(core::int #t2) → void
+    this.{non::Class::_#Class#instanceField} = #t2;
   get finalInstanceField() → dynamic
     return this.{non::Class::_#Class#finalInstanceField#isSet} ?{dynamic} this.{non::Class::_#Class#finalInstanceField} : throw new _in::LateInitializationErrorImpl::•("Field 'finalInstanceField' has not been initialized.");
-  set finalInstanceField(dynamic #t10) → void
+  set finalInstanceField(dynamic #t3) → void
     if(this.{non::Class::_#Class#finalInstanceField#isSet})
       throw new _in::LateInitializationErrorImpl::•("Field 'finalInstanceField' has already been initialized.");
     else {
       this.{non::Class::_#Class#finalInstanceField#isSet} = true;
-      this.{non::Class::_#Class#finalInstanceField} = #t10;
+      this.{non::Class::_#Class#finalInstanceField} = #t3;
     }
   get instanceTypeVariable() → non::Class::T
-    return let final non::Class::T? #t11 = this.{non::Class::_#Class#instanceTypeVariable} in #t11.==(null) ?{non::Class::T} throw new _in::LateInitializationErrorImpl::•("Field 'instanceTypeVariable' has not been initialized.") : #t11{non::Class::T};
-  set instanceTypeVariable(generic-covariant-impl non::Class::T #t12) → void
-    this.{non::Class::_#Class#instanceTypeVariable} = #t12;
+    return let final non::Class::T? #t4 = this.{non::Class::_#Class#instanceTypeVariable} in #t4.==(null) ?{non::Class::T} throw new _in::LateInitializationErrorImpl::•("Field 'instanceTypeVariable' has not been initialized.") : #t4{non::Class::T};
+  set instanceTypeVariable(generic-covariant-impl non::Class::T #t5) → void
+    this.{non::Class::_#Class#instanceTypeVariable} = #t5;
   get finalInstanceTypeVariable() → non::Class::T
-    return let final non::Class::T? #t13 = this.{non::Class::_#Class#finalInstanceTypeVariable} in #t13.==(null) ?{non::Class::T} throw new _in::LateInitializationErrorImpl::•("Field 'finalInstanceTypeVariable' has not been initialized.") : #t13{non::Class::T};
-  set finalInstanceTypeVariable(non::Class::T #t14) → void
+    return let final non::Class::T? #t6 = this.{non::Class::_#Class#finalInstanceTypeVariable} in #t6.==(null) ?{non::Class::T} throw new _in::LateInitializationErrorImpl::•("Field 'finalInstanceTypeVariable' has not been initialized.") : #t6{non::Class::T};
+  set finalInstanceTypeVariable(non::Class::T #t7) → void
     if(this.{non::Class::_#Class#finalInstanceTypeVariable}.==(null))
-      this.{non::Class::_#Class#finalInstanceTypeVariable} = #t14;
+      this.{non::Class::_#Class#finalInstanceTypeVariable} = #t7;
     else
       throw new _in::LateInitializationErrorImpl::•("Field 'finalInstanceTypeVariable' has already been initialized.");
   static get staticField() → core::int
-    return let final core::int? #t15 = non::Class::_#staticField in #t15.==(null) ?{core::int} throw new _in::LateInitializationErrorImpl::•("Field 'staticField' has not been initialized.") : #t15{core::int};
-  static set staticField(core::int #t16) → void
-    non::Class::_#staticField = #t16;
+    return let final core::int? #t8 = non::Class::_#staticField in #t8.==(null) ?{core::int} throw new _in::LateInitializationErrorImpl::•("Field 'staticField' has not been initialized.") : #t8{core::int};
+  static set staticField(core::int #t9) → void
+    non::Class::_#staticField = #t9;
   static get staticFinalField() → dynamic
     return non::Class::_#staticFinalField#isSet ?{dynamic} non::Class::_#staticFinalField : throw new _in::LateInitializationErrorImpl::•("Field 'staticFinalField' has not been initialized.");
-  static set staticFinalField(dynamic #t17) → void
+  static set staticFinalField(dynamic #t10) → void
     if(non::Class::_#staticFinalField#isSet)
       throw new _in::LateInitializationErrorImpl::•("Field 'staticFinalField' has already been initialized.");
     else {
       non::Class::_#staticFinalField#isSet = true;
-      non::Class::_#staticFinalField = #t17;
+      non::Class::_#staticFinalField = #t10;
     }
 }
 static field core::int? _#topLevelField = null;
 static field dynamic _#finalTopLevelField = null;
 static field core::bool _#finalTopLevelField#isSet = false;
 static get topLevelField() → core::int
-  return let final core::int? #t18 = non::_#topLevelField in #t18.==(null) ?{core::int} throw new _in::LateInitializationErrorImpl::•("Field 'topLevelField' has not been initialized.") : #t18{core::int};
-static set topLevelField(core::int #t19) → void
-  non::_#topLevelField = #t19;
+  return let final core::int? #t11 = non::_#topLevelField in #t11.==(null) ?{core::int} throw new _in::LateInitializationErrorImpl::•("Field 'topLevelField' has not been initialized.") : #t11{core::int};
+static set topLevelField(core::int #t12) → void
+  non::_#topLevelField = #t12;
 static get finalTopLevelField() → dynamic
   return non::_#finalTopLevelField#isSet ?{dynamic} non::_#finalTopLevelField : throw new _in::LateInitializationErrorImpl::•("Field 'finalTopLevelField' has not been initialized.");
-static set finalTopLevelField(dynamic #t20) → void
+static set finalTopLevelField(dynamic #t13) → void
   if(non::_#finalTopLevelField#isSet)
     throw new _in::LateInitializationErrorImpl::•("Field 'finalTopLevelField' has already been initialized.");
   else {
     non::_#finalTopLevelField#isSet = true;
-    non::_#finalTopLevelField = #t20;
+    non::_#finalTopLevelField = #t13;
   }
 static method method<T extends core::Object = core::Object>(core::bool b, core::int i, non::method::T t) → dynamic {
   core::int? local;
   function #local#get() → core::int
-    return let final core::int? #t21 = local in #t21.==(null) ?{core::int} throw new _in::LateInitializationErrorImpl::•("Local 'local' has not been initialized.") : #t21{core::int};
-  function #local#set(core::int #t22) → dynamic
-    return local = #t22;
+    return let final core::int? #t14 = local in #t14.==(null) ?{core::int} throw new _in::LateInitializationErrorImpl::•("Local 'local' has not been initialized.") : #t14{core::int};
+  function #local#set(core::int #t15) → dynamic
+    return local = #t15;
   final dynamic finalLocal;
   core::bool #finalLocal#isSet = false;
   function #finalLocal#get() → dynamic
     return #finalLocal#isSet ?{dynamic} finalLocal : throw new _in::LateInitializationErrorImpl::•("Local 'finalLocal' has not been initialized.");
-  function #finalLocal#set(dynamic #t23) → dynamic
+  function #finalLocal#set(dynamic #t16) → dynamic
     if(#finalLocal#isSet)
       throw new _in::LateInitializationErrorImpl::•("Local 'finalLocal' has already been initialized.");
     else {
       #finalLocal#isSet = true;
-      return finalLocal = #t23;
+      return finalLocal = #t16;
     }
   non::method::T? localTypeVariable;
   function #localTypeVariable#get() → non::method::T
-    return let final non::method::T? #t24 = localTypeVariable in #t24.==(null) ?{non::method::T} throw new _in::LateInitializationErrorImpl::•("Local 'localTypeVariable' has not been initialized.") : #t24{non::method::T};
-  function #localTypeVariable#set(non::method::T #t25) → dynamic
-    return localTypeVariable = #t25;
+    return let final non::method::T? #t17 = localTypeVariable in #t17.==(null) ?{non::method::T} throw new _in::LateInitializationErrorImpl::•("Local 'localTypeVariable' has not been initialized.") : #t17{non::method::T};
+  function #localTypeVariable#set(non::method::T #t18) → dynamic
+    return localTypeVariable = #t18;
   final non::method::T? finalLocalTypeVariable;
   function #finalLocalTypeVariable#get() → non::method::T
-    return let final non::method::T? #t26 = finalLocalTypeVariable in #t26.==(null) ?{non::method::T} throw new _in::LateInitializationErrorImpl::•("Local 'finalLocalTypeVariable' has not been initialized.") : #t26{non::method::T};
-  function #finalLocalTypeVariable#set(non::method::T #t27) → dynamic
+    return let final non::method::T? #t19 = finalLocalTypeVariable in #t19.==(null) ?{non::method::T} throw new _in::LateInitializationErrorImpl::•("Local 'finalLocalTypeVariable' has not been initialized.") : #t19{non::method::T};
+  function #finalLocalTypeVariable#set(non::method::T #t20) → dynamic
     if(finalLocalTypeVariable.==(null))
-      return finalLocalTypeVariable = #t27;
+      return finalLocalTypeVariable = #t20;
     else
       throw new _in::LateInitializationErrorImpl::•("Local 'finalLocalTypeVariable' has already been initialized.");
   if(b) {
diff --git a/pkg/front_end/testcases/late_lowering/non_nullable_from_opt_out.dart.strong.transformed.expect b/pkg/front_end/testcases/late_lowering/non_nullable_from_opt_out.dart.strong.transformed.expect
index 0980864..6ffbd4b 100644
--- a/pkg/front_end/testcases/late_lowering/non_nullable_from_opt_out.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/late_lowering/non_nullable_from_opt_out.dart.strong.transformed.expect
@@ -1,4 +1,4 @@
-library /*isNonNullableByDefault*/;
+library;
 //
 // Problems in library:
 //
@@ -6,43 +6,6 @@
 // // @dart=2.8
 // ^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/late_lowering/non_nullable_from_opt_out.dart:10:19: Error: A value of type 'Null' can't be assigned to a variable of type 'int'.
-//   topLevelField = null;
-//                   ^
-//
-// pkg/front_end/testcases/late_lowering/non_nullable_from_opt_out.dart:14:21: Error: A value of type 'Null' can't be assigned to a variable of type 'int'.
-//   c.instanceField = null;
-//                     ^
-//
-// pkg/front_end/testcases/late_lowering/non_nullable_from_opt_out.dart:16:28: Error: A value of type 'Null' can't be assigned to a variable of type 'int'.
-//   c.instanceTypeVariable = null;
-//                            ^
-//
-// pkg/front_end/testcases/late_lowering/non_nullable_from_opt_out.dart:17:33: Error: A value of type 'Null' can't be assigned to a variable of type 'int'.
-//   c.finalInstanceTypeVariable = null;
-//                                 ^
-//
-// pkg/front_end/testcases/late_lowering/non_nullable_from_opt_out.dart:19:23: Error: A value of type 'Null' can't be assigned to a variable of type 'int'.
-//   Class.staticField = null;
-//                       ^
-//
-// pkg/front_end/testcases/late_lowering/non_nullable_from_opt_out.dart:33:46: Error: A value of type 'Null' can't be assigned to a variable of type 'int'.
-//   throws(() => c.finalInstanceTypeVariable = null);
-//                                              ^
-//
-// pkg/front_end/testcases/late_lowering/non_nullable_from_opt_out.dart:36:16: Error: The argument type 'Null' can't be assigned to the parameter type 'int'.
-//   method(true, null, null);
-//                ^
-//
-// pkg/front_end/testcases/late_lowering/non_nullable_from_opt_out.dart:36:3: Error: Inferred type argument 'Null' doesn't conform to the bound 'Object' of the type variable 'T' on 'method'.
-//  - 'Object' is from 'dart:core'.
-// Try specifying type arguments explicitly so that they conform to the bounds.
-//   method(true, null, null);
-//   ^
-// pkg/front_end/testcases/late_lowering/non_nullable_from_opt_out_lib.dart:18:8: Context: This is the type variable whose bound isn't conformed to.
-// method<T extends Object>(bool b, int i, T t) {
-//        ^
-//
 import self as self;
 import "non_nullable_from_opt_out_lib.dart" as non;
 import "dart:core" as core;
@@ -50,24 +13,14 @@
 import "org-dartlang-testcase:///non_nullable_from_opt_out_lib.dart";
 
 static method main() → dynamic {
-  non::topLevelField = let final<BottomType> #t1 = invalid-expression "pkg/front_end/testcases/late_lowering/non_nullable_from_opt_out.dart:10:19: Error: A value of type 'Null' can't be assigned to a variable of type 'int'.
-  topLevelField = null;
-                  ^" in let core::Null? #t2 = null in #t2.==(null) ?{core::int} #t2 as{TypeError,ForNonNullableByDefault} core::int : #t2{core::int};
+  non::topLevelField = null;
   non::finalTopLevelField = null;
-  non::Class<core::int> c = new non::Class::•<core::int>();
-  c.{non::Class::instanceField} = let final<BottomType> #t3 = invalid-expression "pkg/front_end/testcases/late_lowering/non_nullable_from_opt_out.dart:14:21: Error: A value of type 'Null' can't be assigned to a variable of type 'int'.
-  c.instanceField = null;
-                    ^" in let core::Null? #t4 = null in #t4.==(null) ?{core::int} #t4 as{TypeError,ForNonNullableByDefault} core::int : #t4{core::int};
+  non::Class<core::int*>* c = new non::Class::•<core::int*>();
+  c.{non::Class::instanceField} = null;
   c.{non::Class::finalInstanceField} = null;
-  c.{non::Class::instanceTypeVariable} = let final<BottomType> #t5 = invalid-expression "pkg/front_end/testcases/late_lowering/non_nullable_from_opt_out.dart:16:28: Error: A value of type 'Null' can't be assigned to a variable of type 'int'.
-  c.instanceTypeVariable = null;
-                           ^" in let core::Null? #t6 = null in #t6.==(null) ?{core::int} #t6 as{TypeError,ForNonNullableByDefault} core::int : #t6{core::int};
-  c.{non::Class::finalInstanceTypeVariable} = let final<BottomType> #t7 = invalid-expression "pkg/front_end/testcases/late_lowering/non_nullable_from_opt_out.dart:17:33: Error: A value of type 'Null' can't be assigned to a variable of type 'int'.
-  c.finalInstanceTypeVariable = null;
-                                ^" in let core::Null? #t8 = null in #t8.==(null) ?{core::int} #t8 as{TypeError,ForNonNullableByDefault} core::int : #t8{core::int};
-  non::Class::staticField = let final<BottomType> #t9 = invalid-expression "pkg/front_end/testcases/late_lowering/non_nullable_from_opt_out.dart:19:23: Error: A value of type 'Null' can't be assigned to a variable of type 'int'.
-  Class.staticField = null;
-                      ^" in let core::Null? #t10 = null in #t10.==(null) ?{core::int} #t10 as{TypeError,ForNonNullableByDefault} core::int : #t10{core::int};
+  c.{non::Class::instanceTypeVariable} = null;
+  c.{non::Class::finalInstanceTypeVariable} = null;
+  non::Class::staticField = null;
   non::Class::staticFinalField = null;
   non::expect(null, non::topLevelField);
   non::expect(null, non::finalTopLevelField);
@@ -79,13 +32,9 @@
   non::expect(null, non::Class::staticFinalField);
   non::throws(() → core::Null? => non::finalTopLevelField = null);
   non::throws(() → core::Null? => c.{non::Class::finalInstanceField} = null);
-  non::throws(() → core::Null? => c.{non::Class::finalInstanceTypeVariable} = let final<BottomType> #t11 = invalid-expression "pkg/front_end/testcases/late_lowering/non_nullable_from_opt_out.dart:33:46: Error: A value of type 'Null' can't be assigned to a variable of type 'int'.
-  throws(() => c.finalInstanceTypeVariable = null);
-                                             ^" in let core::Null? #t12 = null in #t12.==(null) ?{core::int} #t12 as{TypeError,ForNonNullableByDefault} core::int : #t12{core::int});
+  non::throws(() → core::Null? => c.{non::Class::finalInstanceTypeVariable} = null);
   non::throws(() → core::Null? => non::Class::staticFinalField = null);
-  non::method<core::Null?>(true, let final<BottomType> #t13 = invalid-expression "pkg/front_end/testcases/late_lowering/non_nullable_from_opt_out.dart:36:16: Error: The argument type 'Null' can't be assigned to the parameter type 'int'.
-  method(true, null, null);
-               ^" in let core::Null? #t14 = null in #t14.==(null) ?{core::int} #t14 as{TypeError,ForNonNullableByDefault} core::int : #t14{core::int}, null);
+  non::method<core::Null?>(true, null, null);
 }
 
 library /*isNonNullableByDefault*/;
@@ -106,87 +55,87 @@
     : super core::Object::•()
     ;
   get instanceField() → core::int
-    return let final core::int? #t15 = this.{non::Class::_#Class#instanceField} in #t15.==(null) ?{core::int} throw new _in::LateInitializationErrorImpl::•("Field 'instanceField' has not been initialized.") : #t15{core::int};
-  set instanceField(core::int #t16) → void
-    this.{non::Class::_#Class#instanceField} = #t16;
+    return let final core::int? #t1 = this.{non::Class::_#Class#instanceField} in #t1.==(null) ?{core::int} throw new _in::LateInitializationErrorImpl::•("Field 'instanceField' has not been initialized.") : #t1{core::int};
+  set instanceField(core::int #t2) → void
+    this.{non::Class::_#Class#instanceField} = #t2;
   get finalInstanceField() → dynamic
     return this.{non::Class::_#Class#finalInstanceField#isSet} ?{dynamic} this.{non::Class::_#Class#finalInstanceField} : throw new _in::LateInitializationErrorImpl::•("Field 'finalInstanceField' has not been initialized.");
-  set finalInstanceField(dynamic #t17) → void
+  set finalInstanceField(dynamic #t3) → void
     if(this.{non::Class::_#Class#finalInstanceField#isSet})
       throw new _in::LateInitializationErrorImpl::•("Field 'finalInstanceField' has already been initialized.");
     else {
       this.{non::Class::_#Class#finalInstanceField#isSet} = true;
-      this.{non::Class::_#Class#finalInstanceField} = #t17;
+      this.{non::Class::_#Class#finalInstanceField} = #t3;
     }
   get instanceTypeVariable() → non::Class::T
-    return let final non::Class::T? #t18 = this.{non::Class::_#Class#instanceTypeVariable} in #t18.==(null) ?{non::Class::T} throw new _in::LateInitializationErrorImpl::•("Field 'instanceTypeVariable' has not been initialized.") : #t18{non::Class::T};
-  set instanceTypeVariable(generic-covariant-impl non::Class::T #t19) → void
-    this.{non::Class::_#Class#instanceTypeVariable} = #t19;
+    return let final non::Class::T? #t4 = this.{non::Class::_#Class#instanceTypeVariable} in #t4.==(null) ?{non::Class::T} throw new _in::LateInitializationErrorImpl::•("Field 'instanceTypeVariable' has not been initialized.") : #t4{non::Class::T};
+  set instanceTypeVariable(generic-covariant-impl non::Class::T #t5) → void
+    this.{non::Class::_#Class#instanceTypeVariable} = #t5;
   get finalInstanceTypeVariable() → non::Class::T
-    return let final non::Class::T? #t20 = this.{non::Class::_#Class#finalInstanceTypeVariable} in #t20.==(null) ?{non::Class::T} throw new _in::LateInitializationErrorImpl::•("Field 'finalInstanceTypeVariable' has not been initialized.") : #t20{non::Class::T};
-  set finalInstanceTypeVariable(non::Class::T #t21) → void
+    return let final non::Class::T? #t6 = this.{non::Class::_#Class#finalInstanceTypeVariable} in #t6.==(null) ?{non::Class::T} throw new _in::LateInitializationErrorImpl::•("Field 'finalInstanceTypeVariable' has not been initialized.") : #t6{non::Class::T};
+  set finalInstanceTypeVariable(non::Class::T #t7) → void
     if(this.{non::Class::_#Class#finalInstanceTypeVariable}.==(null))
-      this.{non::Class::_#Class#finalInstanceTypeVariable} = #t21;
+      this.{non::Class::_#Class#finalInstanceTypeVariable} = #t7;
     else
       throw new _in::LateInitializationErrorImpl::•("Field 'finalInstanceTypeVariable' has already been initialized.");
   static get staticField() → core::int
-    return let final core::int? #t22 = non::Class::_#staticField in #t22.==(null) ?{core::int} throw new _in::LateInitializationErrorImpl::•("Field 'staticField' has not been initialized.") : #t22{core::int};
-  static set staticField(core::int #t23) → void
-    non::Class::_#staticField = #t23;
+    return let final core::int? #t8 = non::Class::_#staticField in #t8.==(null) ?{core::int} throw new _in::LateInitializationErrorImpl::•("Field 'staticField' has not been initialized.") : #t8{core::int};
+  static set staticField(core::int #t9) → void
+    non::Class::_#staticField = #t9;
   static get staticFinalField() → dynamic
     return non::Class::_#staticFinalField#isSet ?{dynamic} non::Class::_#staticFinalField : throw new _in::LateInitializationErrorImpl::•("Field 'staticFinalField' has not been initialized.");
-  static set staticFinalField(dynamic #t24) → void
+  static set staticFinalField(dynamic #t10) → void
     if(non::Class::_#staticFinalField#isSet)
       throw new _in::LateInitializationErrorImpl::•("Field 'staticFinalField' has already been initialized.");
     else {
       non::Class::_#staticFinalField#isSet = true;
-      non::Class::_#staticFinalField = #t24;
+      non::Class::_#staticFinalField = #t10;
     }
 }
 static field core::int? _#topLevelField = null;
 static field dynamic _#finalTopLevelField = null;
 static field core::bool _#finalTopLevelField#isSet = false;
 static get topLevelField() → core::int
-  return let final core::int? #t25 = non::_#topLevelField in #t25.==(null) ?{core::int} throw new _in::LateInitializationErrorImpl::•("Field 'topLevelField' has not been initialized.") : #t25{core::int};
-static set topLevelField(core::int #t26) → void
-  non::_#topLevelField = #t26;
+  return let final core::int? #t11 = non::_#topLevelField in #t11.==(null) ?{core::int} throw new _in::LateInitializationErrorImpl::•("Field 'topLevelField' has not been initialized.") : #t11{core::int};
+static set topLevelField(core::int #t12) → void
+  non::_#topLevelField = #t12;
 static get finalTopLevelField() → dynamic
   return non::_#finalTopLevelField#isSet ?{dynamic} non::_#finalTopLevelField : throw new _in::LateInitializationErrorImpl::•("Field 'finalTopLevelField' has not been initialized.");
-static set finalTopLevelField(dynamic #t27) → void
+static set finalTopLevelField(dynamic #t13) → void
   if(non::_#finalTopLevelField#isSet)
     throw new _in::LateInitializationErrorImpl::•("Field 'finalTopLevelField' has already been initialized.");
   else {
     non::_#finalTopLevelField#isSet = true;
-    non::_#finalTopLevelField = #t27;
+    non::_#finalTopLevelField = #t13;
   }
 static method method<T extends core::Object = core::Object>(core::bool b, core::int i, non::method::T t) → dynamic {
   core::int? local;
   function #local#get() → core::int
-    return let final core::int? #t28 = local in #t28.==(null) ?{core::int} throw new _in::LateInitializationErrorImpl::•("Local 'local' has not been initialized.") : #t28{core::int};
-  function #local#set(core::int #t29) → dynamic
-    return local = #t29;
+    return let final core::int? #t14 = local in #t14.==(null) ?{core::int} throw new _in::LateInitializationErrorImpl::•("Local 'local' has not been initialized.") : #t14{core::int};
+  function #local#set(core::int #t15) → dynamic
+    return local = #t15;
   final dynamic finalLocal;
   core::bool #finalLocal#isSet = false;
   function #finalLocal#get() → dynamic
     return #finalLocal#isSet ?{dynamic} finalLocal : throw new _in::LateInitializationErrorImpl::•("Local 'finalLocal' has not been initialized.");
-  function #finalLocal#set(dynamic #t30) → dynamic
+  function #finalLocal#set(dynamic #t16) → dynamic
     if(#finalLocal#isSet)
       throw new _in::LateInitializationErrorImpl::•("Local 'finalLocal' has already been initialized.");
     else {
       #finalLocal#isSet = true;
-      return finalLocal = #t30;
+      return finalLocal = #t16;
     }
   non::method::T? localTypeVariable;
   function #localTypeVariable#get() → non::method::T
-    return let final non::method::T? #t31 = localTypeVariable in #t31.==(null) ?{non::method::T} throw new _in::LateInitializationErrorImpl::•("Local 'localTypeVariable' has not been initialized.") : #t31{non::method::T};
-  function #localTypeVariable#set(non::method::T #t32) → dynamic
-    return localTypeVariable = #t32;
+    return let final non::method::T? #t17 = localTypeVariable in #t17.==(null) ?{non::method::T} throw new _in::LateInitializationErrorImpl::•("Local 'localTypeVariable' has not been initialized.") : #t17{non::method::T};
+  function #localTypeVariable#set(non::method::T #t18) → dynamic
+    return localTypeVariable = #t18;
   final non::method::T? finalLocalTypeVariable;
   function #finalLocalTypeVariable#get() → non::method::T
-    return let final non::method::T? #t33 = finalLocalTypeVariable in #t33.==(null) ?{non::method::T} throw new _in::LateInitializationErrorImpl::•("Local 'finalLocalTypeVariable' has not been initialized.") : #t33{non::method::T};
-  function #finalLocalTypeVariable#set(non::method::T #t34) → dynamic
+    return let final non::method::T? #t19 = finalLocalTypeVariable in #t19.==(null) ?{non::method::T} throw new _in::LateInitializationErrorImpl::•("Local 'finalLocalTypeVariable' has not been initialized.") : #t19{non::method::T};
+  function #finalLocalTypeVariable#set(non::method::T #t20) → dynamic
     if(finalLocalTypeVariable.==(null))
-      return finalLocalTypeVariable = #t34;
+      return finalLocalTypeVariable = #t20;
     else
       throw new _in::LateInitializationErrorImpl::•("Local 'finalLocalTypeVariable' has already been initialized.");
   if(b) {
@@ -215,28 +164,3 @@
   }
   throw "Missing exception";
 }
-
-
-Extra constant evaluation status:
-Evaluated: MethodInvocation @ org-dartlang-testcase:///non_nullable_from_opt_out.dart:10:19 -> BoolConstant(true)
-Evaluated: VariableGet @ org-dartlang-testcase:///non_nullable_from_opt_out.dart:10:19 -> NullConstant(null)
-Evaluated: VariableGet @ org-dartlang-testcase:///non_nullable_from_opt_out.dart:10:19 -> NullConstant(null)
-Evaluated: MethodInvocation @ org-dartlang-testcase:///non_nullable_from_opt_out.dart:14:21 -> BoolConstant(true)
-Evaluated: VariableGet @ org-dartlang-testcase:///non_nullable_from_opt_out.dart:14:21 -> NullConstant(null)
-Evaluated: VariableGet @ org-dartlang-testcase:///non_nullable_from_opt_out.dart:14:21 -> NullConstant(null)
-Evaluated: MethodInvocation @ org-dartlang-testcase:///non_nullable_from_opt_out.dart:16:28 -> BoolConstant(true)
-Evaluated: VariableGet @ org-dartlang-testcase:///non_nullable_from_opt_out.dart:16:28 -> NullConstant(null)
-Evaluated: VariableGet @ org-dartlang-testcase:///non_nullable_from_opt_out.dart:16:28 -> NullConstant(null)
-Evaluated: MethodInvocation @ org-dartlang-testcase:///non_nullable_from_opt_out.dart:17:33 -> BoolConstant(true)
-Evaluated: VariableGet @ org-dartlang-testcase:///non_nullable_from_opt_out.dart:17:33 -> NullConstant(null)
-Evaluated: VariableGet @ org-dartlang-testcase:///non_nullable_from_opt_out.dart:17:33 -> NullConstant(null)
-Evaluated: MethodInvocation @ org-dartlang-testcase:///non_nullable_from_opt_out.dart:19:23 -> BoolConstant(true)
-Evaluated: VariableGet @ org-dartlang-testcase:///non_nullable_from_opt_out.dart:19:23 -> NullConstant(null)
-Evaluated: VariableGet @ org-dartlang-testcase:///non_nullable_from_opt_out.dart:19:23 -> NullConstant(null)
-Evaluated: MethodInvocation @ org-dartlang-testcase:///non_nullable_from_opt_out.dart:33:46 -> BoolConstant(true)
-Evaluated: VariableGet @ org-dartlang-testcase:///non_nullable_from_opt_out.dart:33:46 -> NullConstant(null)
-Evaluated: VariableGet @ org-dartlang-testcase:///non_nullable_from_opt_out.dart:33:46 -> NullConstant(null)
-Evaluated: MethodInvocation @ org-dartlang-testcase:///non_nullable_from_opt_out.dart:36:16 -> BoolConstant(true)
-Evaluated: VariableGet @ org-dartlang-testcase:///non_nullable_from_opt_out.dart:36:16 -> NullConstant(null)
-Evaluated: VariableGet @ org-dartlang-testcase:///non_nullable_from_opt_out.dart:36:16 -> NullConstant(null)
-Extra constant evaluation: evaluated: 291, effectively constant: 21
diff --git a/pkg/front_end/testcases/nnbd/issue43536.dart b/pkg/front_end/testcases/nnbd/issue43536.dart
new file mode 100644
index 0000000..ac26684
--- /dev/null
+++ b/pkg/front_end/testcases/nnbd/issue43536.dart
@@ -0,0 +1,13 @@
+// Copyright (c) 2020, the Dart project authors. Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+class C<T> {
+  foo<E extends T>(List<E> list) {
+    List<E> variable = method(list);
+  }
+
+  List<F> method<F extends T>(List<F> list) => list;
+}
+
+main() {}
diff --git a/pkg/front_end/testcases/nnbd/issue43536.dart.outline.expect b/pkg/front_end/testcases/nnbd/issue43536.dart.outline.expect
new file mode 100644
index 0000000..15e7e74
--- /dev/null
+++ b/pkg/front_end/testcases/nnbd/issue43536.dart.outline.expect
@@ -0,0 +1,14 @@
+library /*isNonNullableByDefault*/;
+import self as self;
+import "dart:core" as core;
+
+class C<T extends core::Object? = dynamic> extends core::Object {
+  synthetic constructor •() → self::C<self::C::T%>
+    ;
+  method foo<generic-covariant-impl E extends self::C::T% = self::C::T%>(core::List<self::C::foo::E%> list) → dynamic
+    ;
+  method method<generic-covariant-impl F extends self::C::T% = self::C::T%>(core::List<self::C::method::F%> list) → core::List<self::C::method::F%>
+    ;
+}
+static method main() → dynamic
+  ;
diff --git a/pkg/front_end/testcases/nnbd/issue43536.dart.strong.expect b/pkg/front_end/testcases/nnbd/issue43536.dart.strong.expect
new file mode 100644
index 0000000..e22d4b0
--- /dev/null
+++ b/pkg/front_end/testcases/nnbd/issue43536.dart.strong.expect
@@ -0,0 +1,15 @@
+library /*isNonNullableByDefault*/;
+import self as self;
+import "dart:core" as core;
+
+class C<T extends core::Object? = dynamic> extends core::Object {
+  synthetic constructor •() → self::C<self::C::T%>
+    : super core::Object::•()
+    ;
+  method foo<generic-covariant-impl E extends self::C::T% = self::C::T%>(core::List<self::C::foo::E%> list) → dynamic {
+    core::List<self::C::foo::E%> variable = this.{self::C::method}<self::C::foo::E%>(list);
+  }
+  method method<generic-covariant-impl F extends self::C::T% = self::C::T%>(core::List<self::C::method::F%> list) → core::List<self::C::method::F%>
+    return list;
+}
+static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/nnbd/issue43536.dart.strong.transformed.expect b/pkg/front_end/testcases/nnbd/issue43536.dart.strong.transformed.expect
new file mode 100644
index 0000000..e22d4b0
--- /dev/null
+++ b/pkg/front_end/testcases/nnbd/issue43536.dart.strong.transformed.expect
@@ -0,0 +1,15 @@
+library /*isNonNullableByDefault*/;
+import self as self;
+import "dart:core" as core;
+
+class C<T extends core::Object? = dynamic> extends core::Object {
+  synthetic constructor •() → self::C<self::C::T%>
+    : super core::Object::•()
+    ;
+  method foo<generic-covariant-impl E extends self::C::T% = self::C::T%>(core::List<self::C::foo::E%> list) → dynamic {
+    core::List<self::C::foo::E%> variable = this.{self::C::method}<self::C::foo::E%>(list);
+  }
+  method method<generic-covariant-impl F extends self::C::T% = self::C::T%>(core::List<self::C::method::F%> list) → core::List<self::C::method::F%>
+    return list;
+}
+static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/nnbd/issue43536.dart.textual_outline.expect b/pkg/front_end/testcases/nnbd/issue43536.dart.textual_outline.expect
new file mode 100644
index 0000000..89b6571
--- /dev/null
+++ b/pkg/front_end/testcases/nnbd/issue43536.dart.textual_outline.expect
@@ -0,0 +1,6 @@
+class C<T> {
+  foo<E extends T>(List<E> list) {}
+  List<F> method<F extends T>(List<F> list) => list;
+}
+
+main() {}
diff --git a/pkg/front_end/testcases/nnbd/issue43536.dart.textual_outline_modelled.expect b/pkg/front_end/testcases/nnbd/issue43536.dart.textual_outline_modelled.expect
new file mode 100644
index 0000000..2ba6b44
--- /dev/null
+++ b/pkg/front_end/testcases/nnbd/issue43536.dart.textual_outline_modelled.expect
@@ -0,0 +1,6 @@
+class C<T> {
+  List<F> method<F extends T>(List<F> list) => list;
+  foo<E extends T>(List<E> list) {}
+}
+
+main() {}
diff --git a/pkg/front_end/testcases/nnbd/issue43536.dart.weak.expect b/pkg/front_end/testcases/nnbd/issue43536.dart.weak.expect
new file mode 100644
index 0000000..e22d4b0
--- /dev/null
+++ b/pkg/front_end/testcases/nnbd/issue43536.dart.weak.expect
@@ -0,0 +1,15 @@
+library /*isNonNullableByDefault*/;
+import self as self;
+import "dart:core" as core;
+
+class C<T extends core::Object? = dynamic> extends core::Object {
+  synthetic constructor •() → self::C<self::C::T%>
+    : super core::Object::•()
+    ;
+  method foo<generic-covariant-impl E extends self::C::T% = self::C::T%>(core::List<self::C::foo::E%> list) → dynamic {
+    core::List<self::C::foo::E%> variable = this.{self::C::method}<self::C::foo::E%>(list);
+  }
+  method method<generic-covariant-impl F extends self::C::T% = self::C::T%>(core::List<self::C::method::F%> list) → core::List<self::C::method::F%>
+    return list;
+}
+static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/nnbd/issue43536.dart.weak.transformed.expect b/pkg/front_end/testcases/nnbd/issue43536.dart.weak.transformed.expect
new file mode 100644
index 0000000..e22d4b0
--- /dev/null
+++ b/pkg/front_end/testcases/nnbd/issue43536.dart.weak.transformed.expect
@@ -0,0 +1,15 @@
+library /*isNonNullableByDefault*/;
+import self as self;
+import "dart:core" as core;
+
+class C<T extends core::Object? = dynamic> extends core::Object {
+  synthetic constructor •() → self::C<self::C::T%>
+    : super core::Object::•()
+    ;
+  method foo<generic-covariant-impl E extends self::C::T% = self::C::T%>(core::List<self::C::foo::E%> list) → dynamic {
+    core::List<self::C::foo::E%> variable = this.{self::C::method}<self::C::foo::E%>(list);
+  }
+  method method<generic-covariant-impl F extends self::C::T% = self::C::T%>(core::List<self::C::method::F%> list) → core::List<self::C::method::F%>
+    return list;
+}
+static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_dill/strong.dart.outline.expect b/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_dill/strong.dart.outline.expect
index acb4c8d..953b07d 100644
--- a/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_dill/strong.dart.outline.expect
+++ b/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_dill/strong.dart.outline.expect
@@ -13,6 +13,8 @@
 
 library;
 import self as self2;
+import "dart:core" as core;
 
+static field core::int* x;
 static method foo() → void
   ;
diff --git a/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_dill/strong.dart.strong.expect b/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_dill/strong.dart.strong.expect
index b5f4dc2..6501ffc 100644
--- a/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_dill/strong.dart.strong.expect
+++ b/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_dill/strong.dart.strong.expect
@@ -17,6 +17,7 @@
 import self as str;
 import "dart:core" as core;
 
+static field core::int* x;
 static method foo() → void {
   core::print("hello");
 }
diff --git a/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_dill/strong.dart.strong.transformed.expect b/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_dill/strong.dart.strong.transformed.expect
index b5f4dc2..6501ffc 100644
--- a/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_dill/strong.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_dill/strong.dart.strong.transformed.expect
@@ -17,6 +17,7 @@
 import self as str;
 import "dart:core" as core;
 
+static field core::int* x;
 static method foo() → void {
   core::print("hello");
 }
diff --git a/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_dill/strong.dart.weak.expect b/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_dill/strong.dart.weak.expect
index dfa3681..c9d352f 100644
--- a/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_dill/strong.dart.weak.expect
+++ b/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_dill/strong.dart.weak.expect
@@ -12,6 +12,7 @@
 import self as str;
 import "dart:core" as core;
 
+static field core::int* x;
 static method foo() → void {
   core::print("hello");
 }
diff --git a/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_dill/strong.dart.weak.transformed.expect b/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_dill/strong.dart.weak.transformed.expect
index dfa3681..c9d352f 100644
--- a/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_dill/strong.dart.weak.transformed.expect
+++ b/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_dill/strong.dart.weak.transformed.expect
@@ -12,6 +12,7 @@
 import self as str;
 import "dart:core" as core;
 
+static field core::int* x;
 static method foo() → void {
   core::print("hello");
 }
diff --git a/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_dill/strong_lib.dart b/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_dill/strong_lib.dart
index 930d387..ed07dd6 100644
--- a/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_dill/strong_lib.dart
+++ b/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_dill/strong_lib.dart
@@ -1,5 +1,7 @@
 // @dart = 2.7
 
+int x;
+
 void foo() {
   print("hello");
 }
diff --git a/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_source/strong.dart.outline.expect b/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_source/strong.dart.outline.expect
index 7a170f8..f0ae2dc 100644
--- a/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_source/strong.dart.outline.expect
+++ b/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_source/strong.dart.outline.expect
@@ -6,7 +6,7 @@
 static method main() → dynamic
   ;
 
-library /*isNonNullableByDefault*/;
+library;
 //
 // Problems in library:
 //
@@ -15,6 +15,8 @@
 // ^^^^^^^^^^^^^^
 //
 import self as self2;
+import "dart:core" as core;
 
+static field core::int* x;
 static method foo() → void
   ;
diff --git a/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_source/strong.dart.strong.expect b/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_source/strong.dart.strong.expect
index 701927d..fecb1f5 100644
--- a/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_source/strong.dart.strong.expect
+++ b/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_source/strong.dart.strong.expect
@@ -8,7 +8,7 @@
   str::foo();
 }
 
-library /*isNonNullableByDefault*/;
+library;
 //
 // Problems in library:
 //
@@ -19,6 +19,7 @@
 import self as str;
 import "dart:core" as core;
 
+static field core::int* x;
 static method foo() → void {
   core::print("hello");
 }
diff --git a/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_source/strong.dart.strong.transformed.expect b/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_source/strong.dart.strong.transformed.expect
index 701927d..fecb1f5 100644
--- a/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_source/strong.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_source/strong.dart.strong.transformed.expect
@@ -8,7 +8,7 @@
   str::foo();
 }
 
-library /*isNonNullableByDefault*/;
+library;
 //
 // Problems in library:
 //
@@ -19,6 +19,7 @@
 import self as str;
 import "dart:core" as core;
 
+static field core::int* x;
 static method foo() → void {
   core::print("hello");
 }
diff --git a/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_source/strong.dart.weak.expect b/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_source/strong.dart.weak.expect
index dfa3681..c9d352f 100644
--- a/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_source/strong.dart.weak.expect
+++ b/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_source/strong.dart.weak.expect
@@ -12,6 +12,7 @@
 import self as str;
 import "dart:core" as core;
 
+static field core::int* x;
 static method foo() → void {
   core::print("hello");
 }
diff --git a/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_source/strong.dart.weak.transformed.expect b/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_source/strong.dart.weak.transformed.expect
index dfa3681..c9d352f 100644
--- a/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_source/strong.dart.weak.transformed.expect
+++ b/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_source/strong.dart.weak.transformed.expect
@@ -12,6 +12,7 @@
 import self as str;
 import "dart:core" as core;
 
+static field core::int* x;
 static method foo() → void {
   core::print("hello");
 }
diff --git a/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_source/strong_lib.dart b/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_source/strong_lib.dart
index 930d387..ed07dd6 100644
--- a/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_source/strong_lib.dart
+++ b/pkg/front_end/testcases/nnbd/strong_lib_not_ok_from_source/strong_lib.dart
@@ -1,5 +1,7 @@
 // @dart = 2.7
 
+int x;
+
 void foo() {
   print("hello");
 }
diff --git a/pkg/front_end/testcases/nnbd/strong_package_not_ok_from_dill/opt_out_package/lib/regular_lib1.dart b/pkg/front_end/testcases/nnbd/strong_package_not_ok_from_dill/opt_out_package/lib/regular_lib1.dart
index a08c72e..a3a3556 100644
--- a/pkg/front_end/testcases/nnbd/strong_package_not_ok_from_dill/opt_out_package/lib/regular_lib1.dart
+++ b/pkg/front_end/testcases/nnbd/strong_package_not_ok_from_dill/opt_out_package/lib/regular_lib1.dart
@@ -1,3 +1,5 @@
 // Copyright (c) 2020, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
+
+int x;
diff --git a/pkg/front_end/testcases/nnbd/strong_package_not_ok_from_dill/opt_out_package/lib/regular_lib2.dart b/pkg/front_end/testcases/nnbd/strong_package_not_ok_from_dill/opt_out_package/lib/regular_lib2.dart
index a08c72e..0ba8a05 100644
--- a/pkg/front_end/testcases/nnbd/strong_package_not_ok_from_dill/opt_out_package/lib/regular_lib2.dart
+++ b/pkg/front_end/testcases/nnbd/strong_package_not_ok_from_dill/opt_out_package/lib/regular_lib2.dart
@@ -1,3 +1,5 @@
 // Copyright (c) 2020, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
+
+int y;
diff --git a/pkg/front_end/testcases/nnbd/strong_package_not_ok_from_source/opt_out_package/lib/regular_lib1.dart b/pkg/front_end/testcases/nnbd/strong_package_not_ok_from_source/opt_out_package/lib/regular_lib1.dart
index a08c72e..a3a3556 100644
--- a/pkg/front_end/testcases/nnbd/strong_package_not_ok_from_source/opt_out_package/lib/regular_lib1.dart
+++ b/pkg/front_end/testcases/nnbd/strong_package_not_ok_from_source/opt_out_package/lib/regular_lib1.dart
@@ -1,3 +1,5 @@
 // Copyright (c) 2020, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
+
+int x;
diff --git a/pkg/front_end/testcases/nnbd/strong_package_not_ok_from_source/opt_out_package/lib/regular_lib2.dart b/pkg/front_end/testcases/nnbd/strong_package_not_ok_from_source/opt_out_package/lib/regular_lib2.dart
index a08c72e..0ba8a05 100644
--- a/pkg/front_end/testcases/nnbd/strong_package_not_ok_from_source/opt_out_package/lib/regular_lib2.dart
+++ b/pkg/front_end/testcases/nnbd/strong_package_not_ok_from_source/opt_out_package/lib/regular_lib2.dart
@@ -1,3 +1,5 @@
 // Copyright (c) 2020, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
+
+int y;
diff --git a/pkg/front_end/testcases/nnbd_mixed/main_declaration.dart b/pkg/front_end/testcases/nnbd_mixed/main_declaration.dart
new file mode 100644
index 0000000..a219889
--- /dev/null
+++ b/pkg/front_end/testcases/nnbd_mixed/main_declaration.dart
@@ -0,0 +1,9 @@
+// Copyright (c) 2020, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// @dart=2.8
+
+import 'main_declaration_lib.dart';
+
+main() {}
diff --git a/pkg/front_end/testcases/nnbd_mixed/main_declaration.dart.textual_outline.expect b/pkg/front_end/testcases/nnbd_mixed/main_declaration.dart.textual_outline.expect
new file mode 100644
index 0000000..34a9e3a
--- /dev/null
+++ b/pkg/front_end/testcases/nnbd_mixed/main_declaration.dart.textual_outline.expect
@@ -0,0 +1,4 @@
+// @dart = 2.8
+import 'main_declaration_lib.dart';
+
+main() {}
diff --git a/pkg/front_end/testcases/nnbd_mixed/main_declaration.dart.textual_outline_modelled.expect b/pkg/front_end/testcases/nnbd_mixed/main_declaration.dart.textual_outline_modelled.expect
new file mode 100644
index 0000000..34a9e3a
--- /dev/null
+++ b/pkg/front_end/testcases/nnbd_mixed/main_declaration.dart.textual_outline_modelled.expect
@@ -0,0 +1,4 @@
+// @dart = 2.8
+import 'main_declaration_lib.dart';
+
+main() {}
diff --git a/pkg/front_end/testcases/nnbd_mixed/main_declaration.dart.weak.expect b/pkg/front_end/testcases/nnbd_mixed/main_declaration.dart.weak.expect
new file mode 100644
index 0000000..58118e1
--- /dev/null
+++ b/pkg/front_end/testcases/nnbd_mixed/main_declaration.dart.weak.expect
@@ -0,0 +1,12 @@
+library;
+import self as self;
+
+import "org-dartlang-testcase:///main_declaration_lib.dart";
+
+static method main() → dynamic {}
+
+library;
+import self as self2;
+import "dart:core" as core;
+
+static method main(core::String* args) → dynamic {}
diff --git a/pkg/front_end/testcases/nnbd_mixed/main_declaration.dart.weak.transformed.expect b/pkg/front_end/testcases/nnbd_mixed/main_declaration.dart.weak.transformed.expect
new file mode 100644
index 0000000..58118e1
--- /dev/null
+++ b/pkg/front_end/testcases/nnbd_mixed/main_declaration.dart.weak.transformed.expect
@@ -0,0 +1,12 @@
+library;
+import self as self;
+
+import "org-dartlang-testcase:///main_declaration_lib.dart";
+
+static method main() → dynamic {}
+
+library;
+import self as self2;
+import "dart:core" as core;
+
+static method main(core::String* args) → dynamic {}
diff --git a/pkg/front_end/testcases/nnbd_mixed/main_declaration_lib.dart b/pkg/front_end/testcases/nnbd_mixed/main_declaration_lib.dart
new file mode 100644
index 0000000..9fb74f3
--- /dev/null
+++ b/pkg/front_end/testcases/nnbd_mixed/main_declaration_lib.dart
@@ -0,0 +1,8 @@
+// Copyright (c) 2020, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// @dart=2.8
+
+// This would be an invalid main declaration in a null safe library.
+main(String args) {}
diff --git a/pkg/front_end/testcases/value_class/value_implements_non_value.dart b/pkg/front_end/testcases/value_class/value_implements_non_value.dart
index ccb27e8..6b6cf57 100644
--- a/pkg/front_end/testcases/value_class/value_implements_non_value.dart
+++ b/pkg/front_end/testcases/value_class/value_implements_non_value.dart
@@ -2,7 +2,6 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-import '../nnbd_mixed/nnbd_opt_out_language_version.dart';
 import 'value_class_support_lib.dart';
 
 class Animal {
diff --git a/pkg/front_end/testcases/value_class/value_implements_non_value.dart.outline.expect b/pkg/front_end/testcases/value_class/value_implements_non_value.dart.outline.expect
index 73b6a82..4896c3e 100644
--- a/pkg/front_end/testcases/value_class/value_implements_non_value.dart.outline.expect
+++ b/pkg/front_end/testcases/value_class/value_implements_non_value.dart.outline.expect
@@ -3,7 +3,6 @@
 import "dart:core" as core;
 import "value_class_support_lib.dart" as val;
 
-import "org-dartlang-testcase-sdk:///pkg/front_end/testcases/nnbd_mixed/nnbd_opt_out_language_version.dart";
 import "org-dartlang-testcase:///value_class_support_lib.dart";
 
 class Animal extends core::Object {
@@ -36,38 +35,6 @@
   ;
 
 library /*isNonNullableByDefault*/;
-//
-// Problems in library:
-//
-// pkg/front_end/testcases/nnbd_mixed/nnbd_opt_out_language_version.dart:1:1: Error: A library can't opt out of null safety by default, when using sound null safety.
-// // @dart=2.4
-// ^^^^^^^^^^^^
-//
-import self as self2;
-import "dart:core" as core;
-
-class late extends core::Object {
-  synthetic constructor •() → self2::late
-    ;
-  get g() → core::int
-    ;
-}
-class required extends core::Object {
-  synthetic constructor •() → self2::required
-    ;
-  get g() → core::int
-    ;
-}
-class C extends core::Object {
-  field self2::late l;
-  field self2::required r;
-  synthetic constructor •() → self2::C
-    ;
-}
-static method main() → dynamic
-  ;
-
-library /*isNonNullableByDefault*/;
 import self as val;
 import "dart:core" as core;
 
@@ -83,6 +50,6 @@
 
 
 Extra constant evaluation status:
-Evaluated: StaticGet @ org-dartlang-testcase:///value_implements_non_value.dart:12:2 -> StringConstant("valueClass")
-Evaluated: StaticGet @ org-dartlang-testcase:///value_implements_non_value.dart:22:2 -> StringConstant("valueClass")
+Evaluated: StaticGet @ org-dartlang-testcase:///value_implements_non_value.dart:11:2 -> StringConstant("valueClass")
+Evaluated: StaticGet @ org-dartlang-testcase:///value_implements_non_value.dart:21:2 -> StringConstant("valueClass")
 Extra constant evaluation: evaluated: 2, effectively constant: 2
diff --git a/pkg/front_end/testcases/value_class/value_implements_non_value.dart.strong.expect b/pkg/front_end/testcases/value_class/value_implements_non_value.dart.strong.expect
index 0c996cf..ea9e6be 100644
--- a/pkg/front_end/testcases/value_class/value_implements_non_value.dart.strong.expect
+++ b/pkg/front_end/testcases/value_class/value_implements_non_value.dart.strong.expect
@@ -2,69 +2,69 @@
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:30:22: Error: No named parameter with the name 'numberOfLegs'.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:29:22: Error: No named parameter with the name 'numberOfLegs'.
 //   Cat firstCat = Cat(numberOfLegs: 4, numberOfWhiskers: 10);
 //                      ^^^^^^^^^^^^
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:13:7: Context: The class 'Cat' has a constructor that takes no arguments.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:12:7: Context: The class 'Cat' has a constructor that takes no arguments.
 // class Cat implements Animal {
 //       ^
 //
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:31:23: Error: No named parameter with the name 'numberOfLegs'.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:30:23: Error: No named parameter with the name 'numberOfLegs'.
 //   Cat secondCat = Cat(numberOfLegs: 4, numberOfWhiskers: 10);
 //                       ^^^^^^^^^^^^
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:13:7: Context: The class 'Cat' has a constructor that takes no arguments.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:12:7: Context: The class 'Cat' has a constructor that takes no arguments.
 // class Cat implements Animal {
 //       ^
 //
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:32:22: Error: No named parameter with the name 'numberOfLegs'.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:31:22: Error: No named parameter with the name 'numberOfLegs'.
 //   Cat thirdCat = Cat(numberOfLegs: 4, numberOfWhiskers: 0);
 //                      ^^^^^^^^^^^^
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:13:7: Context: The class 'Cat' has a constructor that takes no arguments.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:12:7: Context: The class 'Cat' has a constructor that takes no arguments.
 // class Cat implements Animal {
 //       ^
 //
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:40:25: Error: No named parameter with the name 'numberOfLegs'.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:39:25: Error: No named parameter with the name 'numberOfLegs'.
 //   Cat2 firstCat2 = Cat2(numberOfLegs: 4, numberOfWhiskers: 10);
 //                         ^^^^^^^^^^^^
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:23:7: Context: The class 'Cat2' has a constructor that takes no arguments.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:22:7: Context: The class 'Cat2' has a constructor that takes no arguments.
 // class Cat2 implements Animal2 {
 //       ^
 //
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:41:26: Error: No named parameter with the name 'numberOfLegs'.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:40:26: Error: No named parameter with the name 'numberOfLegs'.
 //   Cat2 secondCat2 = Cat2(numberOfLegs: 4, numberOfWhiskers: 10);
 //                          ^^^^^^^^^^^^
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:23:7: Context: The class 'Cat2' has a constructor that takes no arguments.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:22:7: Context: The class 'Cat2' has a constructor that takes no arguments.
 // class Cat2 implements Animal2 {
 //       ^
 //
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:42:25: Error: No named parameter with the name 'numberOfLegs'.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:41:25: Error: No named parameter with the name 'numberOfLegs'.
 //   Cat2 thirdCat2 = Cat2(numberOfLegs: 4, numberOfWhiskers: 0);
 //                         ^^^^^^^^^^^^
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:23:7: Context: The class 'Cat2' has a constructor that takes no arguments.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:22:7: Context: The class 'Cat2' has a constructor that takes no arguments.
 // class Cat2 implements Animal2 {
 //       ^
 //
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:9:13: Error: Final field 'numberOfLegs' is not initialized.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:8:13: Error: Final field 'numberOfLegs' is not initialized.
 // Try to initialize the field in the declaration or in every constructor.
 //   final int numberOfLegs;
 //             ^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:14:13: Error: Final field 'numberOfLegs' is not initialized.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:13:13: Error: Final field 'numberOfLegs' is not initialized.
 // Try to initialize the field in the declaration or in every constructor.
 //   final int numberOfLegs;
 //             ^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:15:13: Error: Final field 'numberOfWhiskers' is not initialized.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:14:13: Error: Final field 'numberOfWhiskers' is not initialized.
 // Try to initialize the field in the declaration or in every constructor.
 //   final int numberOfWhiskers;
 //             ^^^^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:24:13: Error: Final field 'numberOfLegs' is not initialized.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:23:13: Error: Final field 'numberOfLegs' is not initialized.
 // Try to initialize the field in the declaration or in every constructor.
 //   final int numberOfLegs;
 //             ^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:25:13: Error: Final field 'numberOfWhiskers' is not initialized.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:24:13: Error: Final field 'numberOfWhiskers' is not initialized.
 // Try to initialize the field in the declaration or in every constructor.
 //   final int numberOfWhiskers;
 //             ^^^^^^^^^^^^^^^^
@@ -73,7 +73,6 @@
 import "dart:core" as core;
 import "value_class_support_lib.dart" as val;
 
-import "org-dartlang-testcase-sdk:///pkg/front_end/testcases/nnbd_mixed/nnbd_opt_out_language_version.dart";
 import "org-dartlang-testcase:///value_class_support_lib.dart";
 
 class Animal extends core::Object {
@@ -119,26 +118,26 @@
     return new self::Cat2::•(numberOfLegs: numberOfLegs, numberOfWhiskers: numberOfWhiskers);
 }
 static method main() → dynamic {
-  self::Cat firstCat = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:30:22: Error: No named parameter with the name 'numberOfLegs'.
+  self::Cat firstCat = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:29:22: Error: No named parameter with the name 'numberOfLegs'.
   Cat firstCat = Cat(numberOfLegs: 4, numberOfWhiskers: 10);
                      ^^^^^^^^^^^^" as{TypeError,ForDynamic,ForNonNullableByDefault} self::Cat;
-  self::Cat secondCat = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:31:23: Error: No named parameter with the name 'numberOfLegs'.
+  self::Cat secondCat = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:30:23: Error: No named parameter with the name 'numberOfLegs'.
   Cat secondCat = Cat(numberOfLegs: 4, numberOfWhiskers: 10);
                       ^^^^^^^^^^^^" as{TypeError,ForDynamic,ForNonNullableByDefault} self::Cat;
-  self::Cat thirdCat = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:32:22: Error: No named parameter with the name 'numberOfLegs'.
+  self::Cat thirdCat = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:31:22: Error: No named parameter with the name 'numberOfLegs'.
   Cat thirdCat = Cat(numberOfLegs: 4, numberOfWhiskers: 0);
                      ^^^^^^^^^^^^" as{TypeError,ForDynamic,ForNonNullableByDefault} self::Cat;
   self::expect(true, firstCat.{core::Object::==}(secondCat));
   self::expect(false, firstCat.{core::Object::==}(thirdCat));
   self::expect(true, firstCat.{core::Object::hashCode}.{core::num::==}(secondCat.{core::Object::hashCode}));
   self::expect(false, firstCat.{core::Object::hashCode}.{core::num::==}(thirdCat.{core::Object::hashCode}));
-  self::Cat2 firstCat2 = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:40:25: Error: No named parameter with the name 'numberOfLegs'.
+  self::Cat2 firstCat2 = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:39:25: Error: No named parameter with the name 'numberOfLegs'.
   Cat2 firstCat2 = Cat2(numberOfLegs: 4, numberOfWhiskers: 10);
                         ^^^^^^^^^^^^" as{TypeError,ForDynamic,ForNonNullableByDefault} self::Cat2;
-  self::Cat2 secondCat2 = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:41:26: Error: No named parameter with the name 'numberOfLegs'.
+  self::Cat2 secondCat2 = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:40:26: Error: No named parameter with the name 'numberOfLegs'.
   Cat2 secondCat2 = Cat2(numberOfLegs: 4, numberOfWhiskers: 10);
                          ^^^^^^^^^^^^" as{TypeError,ForDynamic,ForNonNullableByDefault} self::Cat2;
-  self::Cat2 thirdCat2 = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:42:25: Error: No named parameter with the name 'numberOfLegs'.
+  self::Cat2 thirdCat2 = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:41:25: Error: No named parameter with the name 'numberOfLegs'.
   Cat2 thirdCat2 = Cat2(numberOfLegs: 4, numberOfWhiskers: 0);
                         ^^^^^^^^^^^^" as{TypeError,ForDynamic,ForNonNullableByDefault} self::Cat2;
   self::expect(true, firstCat2.{core::Object::==}(secondCat2));
@@ -152,68 +151,6 @@
 }
 
 library /*isNonNullableByDefault*/;
-//
-// Problems in library:
-//
-// pkg/front_end/testcases/nnbd_mixed/nnbd_opt_out_language_version.dart:1:1: Error: A library can't opt out of null safety by default, when using sound null safety.
-// // @dart=2.4
-// ^^^^^^^^^^^^
-//
-// pkg/front_end/testcases/nnbd_mixed/nnbd_opt_out_language_version.dart:3:7: Error: Can't use 'late' as a name here.
-// class late {
-//       ^^^^
-//
-// pkg/front_end/testcases/nnbd_mixed/nnbd_opt_out_language_version.dart:7:7: Error: Can't use 'required' as a name here.
-// class required {
-//       ^^^^^^^^
-//
-// pkg/front_end/testcases/nnbd_mixed/nnbd_opt_out_language_version.dart:12:8: Error: Variables must be declared using the keywords 'const', 'final', 'var' or a type name.
-// Try adding the name of the type of the variable or the keyword 'var'.
-//   late l = late();
-//        ^
-//
-// pkg/front_end/testcases/nnbd_mixed/nnbd_opt_out_language_version.dart:13:3: Error: Can't have modifier 'required' here.
-// Try removing 'required'.
-//   required r = required();
-//   ^^^^^^^^
-//
-// pkg/front_end/testcases/nnbd_mixed/nnbd_opt_out_language_version.dart:13:12: Error: Variables must be declared using the keywords 'const', 'final', 'var' or a type name.
-// Try adding the name of the type of the variable or the keyword 'var'.
-//   required r = required();
-//            ^
-//
-import self as self2;
-import "dart:core" as core;
-
-class late extends core::Object {
-  synthetic constructor •() → self2::late
-    : super core::Object::•()
-    ;
-  get g() → core::int
-    return 1;
-}
-class required extends core::Object {
-  synthetic constructor •() → self2::required
-    : super core::Object::•()
-    ;
-  get g() → core::int
-    return 2;
-}
-class C extends core::Object {
-  field self2::late l = new self2::late::•();
-  field self2::required r = new self2::required::•();
-  synthetic constructor •() → self2::C
-    : super core::Object::•()
-    ;
-}
-static method main() → dynamic {
-  if(!new self2::C::•().{self2::C::l}.{self2::late::g}.{core::num::==}(1))
-    throw "Expected 1";
-  if(!new self2::C::•().{self2::C::r}.{self2::required::g}.{core::num::==}(2))
-    throw "Expected 2";
-}
-
-library /*isNonNullableByDefault*/;
 import self as val;
 import "dart:core" as core;
 
diff --git a/pkg/front_end/testcases/value_class/value_implements_non_value.dart.strong.transformed.expect b/pkg/front_end/testcases/value_class/value_implements_non_value.dart.strong.transformed.expect
index 8073f01..dfd6ccf 100644
--- a/pkg/front_end/testcases/value_class/value_implements_non_value.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/value_class/value_implements_non_value.dart.strong.transformed.expect
@@ -2,69 +2,69 @@
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:30:22: Error: No named parameter with the name 'numberOfLegs'.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:29:22: Error: No named parameter with the name 'numberOfLegs'.
 //   Cat firstCat = Cat(numberOfLegs: 4, numberOfWhiskers: 10);
 //                      ^^^^^^^^^^^^
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:13:7: Context: The class 'Cat' has a constructor that takes no arguments.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:12:7: Context: The class 'Cat' has a constructor that takes no arguments.
 // class Cat implements Animal {
 //       ^
 //
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:31:23: Error: No named parameter with the name 'numberOfLegs'.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:30:23: Error: No named parameter with the name 'numberOfLegs'.
 //   Cat secondCat = Cat(numberOfLegs: 4, numberOfWhiskers: 10);
 //                       ^^^^^^^^^^^^
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:13:7: Context: The class 'Cat' has a constructor that takes no arguments.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:12:7: Context: The class 'Cat' has a constructor that takes no arguments.
 // class Cat implements Animal {
 //       ^
 //
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:32:22: Error: No named parameter with the name 'numberOfLegs'.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:31:22: Error: No named parameter with the name 'numberOfLegs'.
 //   Cat thirdCat = Cat(numberOfLegs: 4, numberOfWhiskers: 0);
 //                      ^^^^^^^^^^^^
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:13:7: Context: The class 'Cat' has a constructor that takes no arguments.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:12:7: Context: The class 'Cat' has a constructor that takes no arguments.
 // class Cat implements Animal {
 //       ^
 //
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:40:25: Error: No named parameter with the name 'numberOfLegs'.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:39:25: Error: No named parameter with the name 'numberOfLegs'.
 //   Cat2 firstCat2 = Cat2(numberOfLegs: 4, numberOfWhiskers: 10);
 //                         ^^^^^^^^^^^^
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:23:7: Context: The class 'Cat2' has a constructor that takes no arguments.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:22:7: Context: The class 'Cat2' has a constructor that takes no arguments.
 // class Cat2 implements Animal2 {
 //       ^
 //
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:41:26: Error: No named parameter with the name 'numberOfLegs'.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:40:26: Error: No named parameter with the name 'numberOfLegs'.
 //   Cat2 secondCat2 = Cat2(numberOfLegs: 4, numberOfWhiskers: 10);
 //                          ^^^^^^^^^^^^
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:23:7: Context: The class 'Cat2' has a constructor that takes no arguments.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:22:7: Context: The class 'Cat2' has a constructor that takes no arguments.
 // class Cat2 implements Animal2 {
 //       ^
 //
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:42:25: Error: No named parameter with the name 'numberOfLegs'.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:41:25: Error: No named parameter with the name 'numberOfLegs'.
 //   Cat2 thirdCat2 = Cat2(numberOfLegs: 4, numberOfWhiskers: 0);
 //                         ^^^^^^^^^^^^
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:23:7: Context: The class 'Cat2' has a constructor that takes no arguments.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:22:7: Context: The class 'Cat2' has a constructor that takes no arguments.
 // class Cat2 implements Animal2 {
 //       ^
 //
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:9:13: Error: Final field 'numberOfLegs' is not initialized.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:8:13: Error: Final field 'numberOfLegs' is not initialized.
 // Try to initialize the field in the declaration or in every constructor.
 //   final int numberOfLegs;
 //             ^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:14:13: Error: Final field 'numberOfLegs' is not initialized.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:13:13: Error: Final field 'numberOfLegs' is not initialized.
 // Try to initialize the field in the declaration or in every constructor.
 //   final int numberOfLegs;
 //             ^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:15:13: Error: Final field 'numberOfWhiskers' is not initialized.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:14:13: Error: Final field 'numberOfWhiskers' is not initialized.
 // Try to initialize the field in the declaration or in every constructor.
 //   final int numberOfWhiskers;
 //             ^^^^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:24:13: Error: Final field 'numberOfLegs' is not initialized.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:23:13: Error: Final field 'numberOfLegs' is not initialized.
 // Try to initialize the field in the declaration or in every constructor.
 //   final int numberOfLegs;
 //             ^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:25:13: Error: Final field 'numberOfWhiskers' is not initialized.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:24:13: Error: Final field 'numberOfWhiskers' is not initialized.
 // Try to initialize the field in the declaration or in every constructor.
 //   final int numberOfWhiskers;
 //             ^^^^^^^^^^^^^^^^
@@ -73,7 +73,6 @@
 import "dart:core" as core;
 import "value_class_support_lib.dart" as val;
 
-import "org-dartlang-testcase-sdk:///pkg/front_end/testcases/nnbd_mixed/nnbd_opt_out_language_version.dart";
 import "org-dartlang-testcase:///value_class_support_lib.dart";
 
 class Animal extends core::Object {
@@ -119,26 +118,26 @@
     return new self::Cat2::•(numberOfLegs: numberOfLegs, numberOfWhiskers: numberOfWhiskers);
 }
 static method main() → dynamic {
-  self::Cat firstCat = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:30:22: Error: No named parameter with the name 'numberOfLegs'.
+  self::Cat firstCat = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:29:22: Error: No named parameter with the name 'numberOfLegs'.
   Cat firstCat = Cat(numberOfLegs: 4, numberOfWhiskers: 10);
                      ^^^^^^^^^^^^";
-  self::Cat secondCat = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:31:23: Error: No named parameter with the name 'numberOfLegs'.
+  self::Cat secondCat = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:30:23: Error: No named parameter with the name 'numberOfLegs'.
   Cat secondCat = Cat(numberOfLegs: 4, numberOfWhiskers: 10);
                       ^^^^^^^^^^^^";
-  self::Cat thirdCat = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:32:22: Error: No named parameter with the name 'numberOfLegs'.
+  self::Cat thirdCat = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:31:22: Error: No named parameter with the name 'numberOfLegs'.
   Cat thirdCat = Cat(numberOfLegs: 4, numberOfWhiskers: 0);
                      ^^^^^^^^^^^^";
   self::expect(true, firstCat.{core::Object::==}(secondCat));
   self::expect(false, firstCat.{core::Object::==}(thirdCat));
   self::expect(true, firstCat.{core::Object::hashCode}.{core::num::==}(secondCat.{core::Object::hashCode}));
   self::expect(false, firstCat.{core::Object::hashCode}.{core::num::==}(thirdCat.{core::Object::hashCode}));
-  self::Cat2 firstCat2 = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:40:25: Error: No named parameter with the name 'numberOfLegs'.
+  self::Cat2 firstCat2 = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:39:25: Error: No named parameter with the name 'numberOfLegs'.
   Cat2 firstCat2 = Cat2(numberOfLegs: 4, numberOfWhiskers: 10);
                         ^^^^^^^^^^^^";
-  self::Cat2 secondCat2 = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:41:26: Error: No named parameter with the name 'numberOfLegs'.
+  self::Cat2 secondCat2 = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:40:26: Error: No named parameter with the name 'numberOfLegs'.
   Cat2 secondCat2 = Cat2(numberOfLegs: 4, numberOfWhiskers: 10);
                          ^^^^^^^^^^^^";
-  self::Cat2 thirdCat2 = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:42:25: Error: No named parameter with the name 'numberOfLegs'.
+  self::Cat2 thirdCat2 = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:41:25: Error: No named parameter with the name 'numberOfLegs'.
   Cat2 thirdCat2 = Cat2(numberOfLegs: 4, numberOfWhiskers: 0);
                         ^^^^^^^^^^^^";
   self::expect(true, firstCat2.{core::Object::==}(secondCat2));
@@ -152,68 +151,6 @@
 }
 
 library /*isNonNullableByDefault*/;
-//
-// Problems in library:
-//
-// pkg/front_end/testcases/nnbd_mixed/nnbd_opt_out_language_version.dart:1:1: Error: A library can't opt out of null safety by default, when using sound null safety.
-// // @dart=2.4
-// ^^^^^^^^^^^^
-//
-// pkg/front_end/testcases/nnbd_mixed/nnbd_opt_out_language_version.dart:3:7: Error: Can't use 'late' as a name here.
-// class late {
-//       ^^^^
-//
-// pkg/front_end/testcases/nnbd_mixed/nnbd_opt_out_language_version.dart:7:7: Error: Can't use 'required' as a name here.
-// class required {
-//       ^^^^^^^^
-//
-// pkg/front_end/testcases/nnbd_mixed/nnbd_opt_out_language_version.dart:12:8: Error: Variables must be declared using the keywords 'const', 'final', 'var' or a type name.
-// Try adding the name of the type of the variable or the keyword 'var'.
-//   late l = late();
-//        ^
-//
-// pkg/front_end/testcases/nnbd_mixed/nnbd_opt_out_language_version.dart:13:3: Error: Can't have modifier 'required' here.
-// Try removing 'required'.
-//   required r = required();
-//   ^^^^^^^^
-//
-// pkg/front_end/testcases/nnbd_mixed/nnbd_opt_out_language_version.dart:13:12: Error: Variables must be declared using the keywords 'const', 'final', 'var' or a type name.
-// Try adding the name of the type of the variable or the keyword 'var'.
-//   required r = required();
-//            ^
-//
-import self as self2;
-import "dart:core" as core;
-
-class late extends core::Object {
-  synthetic constructor •() → self2::late
-    : super core::Object::•()
-    ;
-  get g() → core::int
-    return 1;
-}
-class required extends core::Object {
-  synthetic constructor •() → self2::required
-    : super core::Object::•()
-    ;
-  get g() → core::int
-    return 2;
-}
-class C extends core::Object {
-  field self2::late l = new self2::late::•();
-  field self2::required r = new self2::required::•();
-  synthetic constructor •() → self2::C
-    : super core::Object::•()
-    ;
-}
-static method main() → dynamic {
-  if(!new self2::C::•().{self2::C::l}.{self2::late::g}.{core::num::==}(1))
-    throw "Expected 1";
-  if(!new self2::C::•().{self2::C::r}.{self2::required::g}.{core::num::==}(2))
-    throw "Expected 2";
-}
-
-library /*isNonNullableByDefault*/;
 import self as val;
 import "dart:core" as core;
 
diff --git a/pkg/front_end/testcases/value_class/value_implements_non_value.dart.textual_outline.expect b/pkg/front_end/testcases/value_class/value_implements_non_value.dart.textual_outline.expect
index 2d8e9d2..bf86aab 100644
--- a/pkg/front_end/testcases/value_class/value_implements_non_value.dart.textual_outline.expect
+++ b/pkg/front_end/testcases/value_class/value_implements_non_value.dart.textual_outline.expect
@@ -1,4 +1,3 @@
-import '../nnbd_mixed/nnbd_opt_out_language_version.dart';
 import 'value_class_support_lib.dart';
 
 class Animal {
diff --git a/pkg/front_end/testcases/value_class/value_implements_non_value.dart.textual_outline_modelled.expect b/pkg/front_end/testcases/value_class/value_implements_non_value.dart.textual_outline_modelled.expect
index 43b3505..0b34b85 100644
--- a/pkg/front_end/testcases/value_class/value_implements_non_value.dart.textual_outline_modelled.expect
+++ b/pkg/front_end/testcases/value_class/value_implements_non_value.dart.textual_outline_modelled.expect
@@ -1,4 +1,3 @@
-import '../nnbd_mixed/nnbd_opt_out_language_version.dart';
 import 'value_class_support_lib.dart';
 
 abstract class Animal2 {
diff --git a/pkg/front_end/testcases/value_class/value_implements_non_value.dart.weak.expect b/pkg/front_end/testcases/value_class/value_implements_non_value.dart.weak.expect
index 25f2810..ea9e6be 100644
--- a/pkg/front_end/testcases/value_class/value_implements_non_value.dart.weak.expect
+++ b/pkg/front_end/testcases/value_class/value_implements_non_value.dart.weak.expect
@@ -2,69 +2,69 @@
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:30:22: Error: No named parameter with the name 'numberOfLegs'.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:29:22: Error: No named parameter with the name 'numberOfLegs'.
 //   Cat firstCat = Cat(numberOfLegs: 4, numberOfWhiskers: 10);
 //                      ^^^^^^^^^^^^
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:13:7: Context: The class 'Cat' has a constructor that takes no arguments.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:12:7: Context: The class 'Cat' has a constructor that takes no arguments.
 // class Cat implements Animal {
 //       ^
 //
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:31:23: Error: No named parameter with the name 'numberOfLegs'.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:30:23: Error: No named parameter with the name 'numberOfLegs'.
 //   Cat secondCat = Cat(numberOfLegs: 4, numberOfWhiskers: 10);
 //                       ^^^^^^^^^^^^
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:13:7: Context: The class 'Cat' has a constructor that takes no arguments.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:12:7: Context: The class 'Cat' has a constructor that takes no arguments.
 // class Cat implements Animal {
 //       ^
 //
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:32:22: Error: No named parameter with the name 'numberOfLegs'.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:31:22: Error: No named parameter with the name 'numberOfLegs'.
 //   Cat thirdCat = Cat(numberOfLegs: 4, numberOfWhiskers: 0);
 //                      ^^^^^^^^^^^^
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:13:7: Context: The class 'Cat' has a constructor that takes no arguments.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:12:7: Context: The class 'Cat' has a constructor that takes no arguments.
 // class Cat implements Animal {
 //       ^
 //
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:40:25: Error: No named parameter with the name 'numberOfLegs'.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:39:25: Error: No named parameter with the name 'numberOfLegs'.
 //   Cat2 firstCat2 = Cat2(numberOfLegs: 4, numberOfWhiskers: 10);
 //                         ^^^^^^^^^^^^
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:23:7: Context: The class 'Cat2' has a constructor that takes no arguments.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:22:7: Context: The class 'Cat2' has a constructor that takes no arguments.
 // class Cat2 implements Animal2 {
 //       ^
 //
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:41:26: Error: No named parameter with the name 'numberOfLegs'.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:40:26: Error: No named parameter with the name 'numberOfLegs'.
 //   Cat2 secondCat2 = Cat2(numberOfLegs: 4, numberOfWhiskers: 10);
 //                          ^^^^^^^^^^^^
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:23:7: Context: The class 'Cat2' has a constructor that takes no arguments.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:22:7: Context: The class 'Cat2' has a constructor that takes no arguments.
 // class Cat2 implements Animal2 {
 //       ^
 //
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:42:25: Error: No named parameter with the name 'numberOfLegs'.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:41:25: Error: No named parameter with the name 'numberOfLegs'.
 //   Cat2 thirdCat2 = Cat2(numberOfLegs: 4, numberOfWhiskers: 0);
 //                         ^^^^^^^^^^^^
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:23:7: Context: The class 'Cat2' has a constructor that takes no arguments.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:22:7: Context: The class 'Cat2' has a constructor that takes no arguments.
 // class Cat2 implements Animal2 {
 //       ^
 //
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:9:13: Error: Final field 'numberOfLegs' is not initialized.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:8:13: Error: Final field 'numberOfLegs' is not initialized.
 // Try to initialize the field in the declaration or in every constructor.
 //   final int numberOfLegs;
 //             ^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:14:13: Error: Final field 'numberOfLegs' is not initialized.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:13:13: Error: Final field 'numberOfLegs' is not initialized.
 // Try to initialize the field in the declaration or in every constructor.
 //   final int numberOfLegs;
 //             ^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:15:13: Error: Final field 'numberOfWhiskers' is not initialized.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:14:13: Error: Final field 'numberOfWhiskers' is not initialized.
 // Try to initialize the field in the declaration or in every constructor.
 //   final int numberOfWhiskers;
 //             ^^^^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:24:13: Error: Final field 'numberOfLegs' is not initialized.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:23:13: Error: Final field 'numberOfLegs' is not initialized.
 // Try to initialize the field in the declaration or in every constructor.
 //   final int numberOfLegs;
 //             ^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:25:13: Error: Final field 'numberOfWhiskers' is not initialized.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:24:13: Error: Final field 'numberOfWhiskers' is not initialized.
 // Try to initialize the field in the declaration or in every constructor.
 //   final int numberOfWhiskers;
 //             ^^^^^^^^^^^^^^^^
@@ -73,7 +73,6 @@
 import "dart:core" as core;
 import "value_class_support_lib.dart" as val;
 
-import "org-dartlang-testcase-sdk:///pkg/front_end/testcases/nnbd_mixed/nnbd_opt_out_language_version.dart";
 import "org-dartlang-testcase:///value_class_support_lib.dart";
 
 class Animal extends core::Object {
@@ -119,26 +118,26 @@
     return new self::Cat2::•(numberOfLegs: numberOfLegs, numberOfWhiskers: numberOfWhiskers);
 }
 static method main() → dynamic {
-  self::Cat firstCat = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:30:22: Error: No named parameter with the name 'numberOfLegs'.
+  self::Cat firstCat = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:29:22: Error: No named parameter with the name 'numberOfLegs'.
   Cat firstCat = Cat(numberOfLegs: 4, numberOfWhiskers: 10);
                      ^^^^^^^^^^^^" as{TypeError,ForDynamic,ForNonNullableByDefault} self::Cat;
-  self::Cat secondCat = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:31:23: Error: No named parameter with the name 'numberOfLegs'.
+  self::Cat secondCat = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:30:23: Error: No named parameter with the name 'numberOfLegs'.
   Cat secondCat = Cat(numberOfLegs: 4, numberOfWhiskers: 10);
                       ^^^^^^^^^^^^" as{TypeError,ForDynamic,ForNonNullableByDefault} self::Cat;
-  self::Cat thirdCat = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:32:22: Error: No named parameter with the name 'numberOfLegs'.
+  self::Cat thirdCat = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:31:22: Error: No named parameter with the name 'numberOfLegs'.
   Cat thirdCat = Cat(numberOfLegs: 4, numberOfWhiskers: 0);
                      ^^^^^^^^^^^^" as{TypeError,ForDynamic,ForNonNullableByDefault} self::Cat;
   self::expect(true, firstCat.{core::Object::==}(secondCat));
   self::expect(false, firstCat.{core::Object::==}(thirdCat));
   self::expect(true, firstCat.{core::Object::hashCode}.{core::num::==}(secondCat.{core::Object::hashCode}));
   self::expect(false, firstCat.{core::Object::hashCode}.{core::num::==}(thirdCat.{core::Object::hashCode}));
-  self::Cat2 firstCat2 = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:40:25: Error: No named parameter with the name 'numberOfLegs'.
+  self::Cat2 firstCat2 = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:39:25: Error: No named parameter with the name 'numberOfLegs'.
   Cat2 firstCat2 = Cat2(numberOfLegs: 4, numberOfWhiskers: 10);
                         ^^^^^^^^^^^^" as{TypeError,ForDynamic,ForNonNullableByDefault} self::Cat2;
-  self::Cat2 secondCat2 = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:41:26: Error: No named parameter with the name 'numberOfLegs'.
+  self::Cat2 secondCat2 = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:40:26: Error: No named parameter with the name 'numberOfLegs'.
   Cat2 secondCat2 = Cat2(numberOfLegs: 4, numberOfWhiskers: 10);
                          ^^^^^^^^^^^^" as{TypeError,ForDynamic,ForNonNullableByDefault} self::Cat2;
-  self::Cat2 thirdCat2 = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:42:25: Error: No named parameter with the name 'numberOfLegs'.
+  self::Cat2 thirdCat2 = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:41:25: Error: No named parameter with the name 'numberOfLegs'.
   Cat2 thirdCat2 = Cat2(numberOfLegs: 4, numberOfWhiskers: 0);
                         ^^^^^^^^^^^^" as{TypeError,ForDynamic,ForNonNullableByDefault} self::Cat2;
   self::expect(true, firstCat2.{core::Object::==}(secondCat2));
@@ -151,68 +150,6 @@
     throw "Expected=${expected}, actual=${actual}";
 }
 
-library;
-import self as self2;
-import "dart:core" as core;
-
-class late extends core::Object {
-  synthetic constructor •() → self2::late*
-    : super core::Object::•()
-    ;
-  get g() → core::int*
-    return 1;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
-}
-class required extends core::Object {
-  synthetic constructor •() → self2::required*
-    : super core::Object::•()
-    ;
-  get g() → core::int*
-    return 2;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
-}
-class C extends core::Object {
-  field self2::late* l = new self2::late::•();
-  field self2::required* r = new self2::required::•();
-  synthetic constructor •() → self2::C*
-    : super core::Object::•()
-    ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
-}
-static method main() → dynamic {
-  if(!new self2::C::•().{self2::C::l}.{self2::late::g}.{core::num::==}(1))
-    throw "Expected 1";
-  if(!new self2::C::•().{self2::C::r}.{self2::required::g}.{core::num::==}(2))
-    throw "Expected 2";
-}
-
 library /*isNonNullableByDefault*/;
 import self as val;
 import "dart:core" as core;
diff --git a/pkg/front_end/testcases/value_class/value_implements_non_value.dart.weak.transformed.expect b/pkg/front_end/testcases/value_class/value_implements_non_value.dart.weak.transformed.expect
index 97545af..dfd6ccf 100644
--- a/pkg/front_end/testcases/value_class/value_implements_non_value.dart.weak.transformed.expect
+++ b/pkg/front_end/testcases/value_class/value_implements_non_value.dart.weak.transformed.expect
@@ -2,69 +2,69 @@
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:30:22: Error: No named parameter with the name 'numberOfLegs'.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:29:22: Error: No named parameter with the name 'numberOfLegs'.
 //   Cat firstCat = Cat(numberOfLegs: 4, numberOfWhiskers: 10);
 //                      ^^^^^^^^^^^^
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:13:7: Context: The class 'Cat' has a constructor that takes no arguments.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:12:7: Context: The class 'Cat' has a constructor that takes no arguments.
 // class Cat implements Animal {
 //       ^
 //
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:31:23: Error: No named parameter with the name 'numberOfLegs'.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:30:23: Error: No named parameter with the name 'numberOfLegs'.
 //   Cat secondCat = Cat(numberOfLegs: 4, numberOfWhiskers: 10);
 //                       ^^^^^^^^^^^^
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:13:7: Context: The class 'Cat' has a constructor that takes no arguments.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:12:7: Context: The class 'Cat' has a constructor that takes no arguments.
 // class Cat implements Animal {
 //       ^
 //
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:32:22: Error: No named parameter with the name 'numberOfLegs'.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:31:22: Error: No named parameter with the name 'numberOfLegs'.
 //   Cat thirdCat = Cat(numberOfLegs: 4, numberOfWhiskers: 0);
 //                      ^^^^^^^^^^^^
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:13:7: Context: The class 'Cat' has a constructor that takes no arguments.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:12:7: Context: The class 'Cat' has a constructor that takes no arguments.
 // class Cat implements Animal {
 //       ^
 //
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:40:25: Error: No named parameter with the name 'numberOfLegs'.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:39:25: Error: No named parameter with the name 'numberOfLegs'.
 //   Cat2 firstCat2 = Cat2(numberOfLegs: 4, numberOfWhiskers: 10);
 //                         ^^^^^^^^^^^^
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:23:7: Context: The class 'Cat2' has a constructor that takes no arguments.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:22:7: Context: The class 'Cat2' has a constructor that takes no arguments.
 // class Cat2 implements Animal2 {
 //       ^
 //
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:41:26: Error: No named parameter with the name 'numberOfLegs'.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:40:26: Error: No named parameter with the name 'numberOfLegs'.
 //   Cat2 secondCat2 = Cat2(numberOfLegs: 4, numberOfWhiskers: 10);
 //                          ^^^^^^^^^^^^
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:23:7: Context: The class 'Cat2' has a constructor that takes no arguments.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:22:7: Context: The class 'Cat2' has a constructor that takes no arguments.
 // class Cat2 implements Animal2 {
 //       ^
 //
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:42:25: Error: No named parameter with the name 'numberOfLegs'.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:41:25: Error: No named parameter with the name 'numberOfLegs'.
 //   Cat2 thirdCat2 = Cat2(numberOfLegs: 4, numberOfWhiskers: 0);
 //                         ^^^^^^^^^^^^
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:23:7: Context: The class 'Cat2' has a constructor that takes no arguments.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:22:7: Context: The class 'Cat2' has a constructor that takes no arguments.
 // class Cat2 implements Animal2 {
 //       ^
 //
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:9:13: Error: Final field 'numberOfLegs' is not initialized.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:8:13: Error: Final field 'numberOfLegs' is not initialized.
 // Try to initialize the field in the declaration or in every constructor.
 //   final int numberOfLegs;
 //             ^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:14:13: Error: Final field 'numberOfLegs' is not initialized.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:13:13: Error: Final field 'numberOfLegs' is not initialized.
 // Try to initialize the field in the declaration or in every constructor.
 //   final int numberOfLegs;
 //             ^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:15:13: Error: Final field 'numberOfWhiskers' is not initialized.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:14:13: Error: Final field 'numberOfWhiskers' is not initialized.
 // Try to initialize the field in the declaration or in every constructor.
 //   final int numberOfWhiskers;
 //             ^^^^^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:24:13: Error: Final field 'numberOfLegs' is not initialized.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:23:13: Error: Final field 'numberOfLegs' is not initialized.
 // Try to initialize the field in the declaration or in every constructor.
 //   final int numberOfLegs;
 //             ^^^^^^^^^^^^
 //
-// pkg/front_end/testcases/value_class/value_implements_non_value.dart:25:13: Error: Final field 'numberOfWhiskers' is not initialized.
+// pkg/front_end/testcases/value_class/value_implements_non_value.dart:24:13: Error: Final field 'numberOfWhiskers' is not initialized.
 // Try to initialize the field in the declaration or in every constructor.
 //   final int numberOfWhiskers;
 //             ^^^^^^^^^^^^^^^^
@@ -73,7 +73,6 @@
 import "dart:core" as core;
 import "value_class_support_lib.dart" as val;
 
-import "org-dartlang-testcase-sdk:///pkg/front_end/testcases/nnbd_mixed/nnbd_opt_out_language_version.dart";
 import "org-dartlang-testcase:///value_class_support_lib.dart";
 
 class Animal extends core::Object {
@@ -119,26 +118,26 @@
     return new self::Cat2::•(numberOfLegs: numberOfLegs, numberOfWhiskers: numberOfWhiskers);
 }
 static method main() → dynamic {
-  self::Cat firstCat = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:30:22: Error: No named parameter with the name 'numberOfLegs'.
+  self::Cat firstCat = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:29:22: Error: No named parameter with the name 'numberOfLegs'.
   Cat firstCat = Cat(numberOfLegs: 4, numberOfWhiskers: 10);
                      ^^^^^^^^^^^^";
-  self::Cat secondCat = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:31:23: Error: No named parameter with the name 'numberOfLegs'.
+  self::Cat secondCat = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:30:23: Error: No named parameter with the name 'numberOfLegs'.
   Cat secondCat = Cat(numberOfLegs: 4, numberOfWhiskers: 10);
                       ^^^^^^^^^^^^";
-  self::Cat thirdCat = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:32:22: Error: No named parameter with the name 'numberOfLegs'.
+  self::Cat thirdCat = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:31:22: Error: No named parameter with the name 'numberOfLegs'.
   Cat thirdCat = Cat(numberOfLegs: 4, numberOfWhiskers: 0);
                      ^^^^^^^^^^^^";
   self::expect(true, firstCat.{core::Object::==}(secondCat));
   self::expect(false, firstCat.{core::Object::==}(thirdCat));
   self::expect(true, firstCat.{core::Object::hashCode}.{core::num::==}(secondCat.{core::Object::hashCode}));
   self::expect(false, firstCat.{core::Object::hashCode}.{core::num::==}(thirdCat.{core::Object::hashCode}));
-  self::Cat2 firstCat2 = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:40:25: Error: No named parameter with the name 'numberOfLegs'.
+  self::Cat2 firstCat2 = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:39:25: Error: No named parameter with the name 'numberOfLegs'.
   Cat2 firstCat2 = Cat2(numberOfLegs: 4, numberOfWhiskers: 10);
                         ^^^^^^^^^^^^";
-  self::Cat2 secondCat2 = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:41:26: Error: No named parameter with the name 'numberOfLegs'.
+  self::Cat2 secondCat2 = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:40:26: Error: No named parameter with the name 'numberOfLegs'.
   Cat2 secondCat2 = Cat2(numberOfLegs: 4, numberOfWhiskers: 10);
                          ^^^^^^^^^^^^";
-  self::Cat2 thirdCat2 = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:42:25: Error: No named parameter with the name 'numberOfLegs'.
+  self::Cat2 thirdCat2 = invalid-expression "pkg/front_end/testcases/value_class/value_implements_non_value.dart:41:25: Error: No named parameter with the name 'numberOfLegs'.
   Cat2 thirdCat2 = Cat2(numberOfLegs: 4, numberOfWhiskers: 0);
                         ^^^^^^^^^^^^";
   self::expect(true, firstCat2.{core::Object::==}(secondCat2));
@@ -151,68 +150,6 @@
     throw "Expected=${expected}, actual=${actual}";
 }
 
-library;
-import self as self2;
-import "dart:core" as core;
-
-class late extends core::Object {
-  synthetic constructor •() → self2::late*
-    : super core::Object::•()
-    ;
-  get g() → core::int*
-    return 1;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
-}
-class required extends core::Object {
-  synthetic constructor •() → self2::required*
-    : super core::Object::•()
-    ;
-  get g() → core::int*
-    return 2;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
-}
-class C extends core::Object {
-  field self2::late* l = new self2::late::•();
-  field self2::required* r = new self2::required::•();
-  synthetic constructor •() → self2::C*
-    : super core::Object::•()
-    ;
-  abstract member-signature get _identityHashCode() → core::int*; -> core::Object::_identityHashCode
-  abstract member-signature method _instanceOf(dynamic instantiatorTypeArguments, dynamic functionTypeArguments, dynamic type) → core::bool*; -> core::Object::_instanceOf
-  abstract member-signature method _simpleInstanceOf(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOf
-  abstract member-signature method _simpleInstanceOfTrue(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfTrue
-  abstract member-signature method _simpleInstanceOfFalse(dynamic type) → core::bool*; -> core::Object::_simpleInstanceOfFalse
-  abstract member-signature operator ==(dynamic other) → core::bool*; -> core::Object::==
-  abstract member-signature get hashCode() → core::int*; -> core::Object::hashCode
-  abstract member-signature method toString() → core::String*; -> core::Object::toString
-  abstract member-signature method noSuchMethod(core::Invocation* invocation) → dynamic; -> core::Object::noSuchMethod
-  abstract member-signature get runtimeType() → core::Type*; -> core::Object::runtimeType
-}
-static method main() → dynamic {
-  if(!new self2::C::•().{self2::C::l}.{self2::late::g}.{core::num::==}(1))
-    throw "Expected 1";
-  if(!new self2::C::•().{self2::C::r}.{self2::required::g}.{core::num::==}(2))
-    throw "Expected 2";
-}
-
 library /*isNonNullableByDefault*/;
 import self as val;
 import "dart:core" as core;
diff --git a/pkg/kernel/lib/src/standard_bounds.dart b/pkg/kernel/lib/src/standard_bounds.dart
index 51a5ab9..15d25e9 100644
--- a/pkg/kernel/lib/src/standard_bounds.dart
+++ b/pkg/kernel/lib/src/standard_bounds.dart
@@ -396,17 +396,19 @@
     // without using the nullability of the outermost type. The result uses
     // [intersectNullabilities] to compute the resulting type if the subtype
     // relation is established.
-    DartType nonNullableType1 =
-        type1.withDeclaredNullability(Nullability.nonNullable);
-    DartType nonNullableType2 =
-        type2.withDeclaredNullability(Nullability.nonNullable);
-    if (isSubtypeOf(nonNullableType1, nonNullableType2,
-        SubtypeCheckMode.withNullabilities)) {
+    DartType typeWithoutNullabilityMarker1 =
+        computeTypeWithoutNullabilityMarker(type1, clientLibrary,
+            nullType: coreTypes.nullType);
+    DartType typeWithoutNullabilityMarker2 =
+        computeTypeWithoutNullabilityMarker(type2, clientLibrary,
+            nullType: coreTypes.nullType);
+    if (isSubtypeOf(typeWithoutNullabilityMarker1,
+        typeWithoutNullabilityMarker2, SubtypeCheckMode.withNullabilities)) {
       return type1.withDeclaredNullability(intersectNullabilities(
           type1.declaredNullability, type2.declaredNullability));
     }
-    if (isSubtypeOf(nonNullableType2, nonNullableType1,
-        SubtypeCheckMode.withNullabilities)) {
+    if (isSubtypeOf(typeWithoutNullabilityMarker2,
+        typeWithoutNullabilityMarker1, SubtypeCheckMode.withNullabilities)) {
       return type2.withDeclaredNullability(intersectNullabilities(
           type1.declaredNullability, type2.declaredNullability));
     }
@@ -753,21 +755,23 @@
     // T1 <: T2 without using the nullability of the outermost type. The result
     // uses [uniteNullabilities] to compute the resulting type if the subtype
     // relation is established.
-    InterfaceType nonNonNullableType1 =
-        type1.withDeclaredNullability(Nullability.nonNullable);
-    InterfaceType nonNonNullableType2 =
-        type2.withDeclaredNullability(Nullability.nonNullable);
+    InterfaceType typeWithoutNullabilityMarker1 =
+        computeTypeWithoutNullabilityMarker(type1, clientLibrary,
+            nullType: coreTypes.nullType);
+    InterfaceType typeWithoutNullabilityMarker2 =
+        computeTypeWithoutNullabilityMarker(type2, clientLibrary,
+            nullType: coreTypes.nullType);
 
-    if (isSubtypeOf(nonNonNullableType1, nonNonNullableType2,
-        SubtypeCheckMode.withNullabilities)) {
+    if (isSubtypeOf(typeWithoutNullabilityMarker1,
+        typeWithoutNullabilityMarker2, SubtypeCheckMode.withNullabilities)) {
       return type2.withDeclaredNullability(
           uniteNullabilities(type1.nullability, type2.nullability));
     }
 
     // UP(T1, T2) = T1 if T2 <: T1
     //   Note that both types must be class types at this point.
-    if (isSubtypeOf(nonNonNullableType2, nonNonNullableType1,
-        SubtypeCheckMode.withNullabilities)) {
+    if (isSubtypeOf(typeWithoutNullabilityMarker2,
+        typeWithoutNullabilityMarker1, SubtypeCheckMode.withNullabilities)) {
       return type1.withDeclaredNullability(uniteNullabilities(
           type1.declaredNullability, type2.declaredNullability));
     }
diff --git a/pkg/kernel/lib/type_algebra.dart b/pkg/kernel/lib/type_algebra.dart
index 632c18d..dccad1c 100644
--- a/pkg/kernel/lib/type_algebra.dart
+++ b/pkg/kernel/lib/type_algebra.dart
@@ -1035,16 +1035,18 @@
 
 /// Implementation of [unwrapNullabilityConstructor] as a visitor.
 ///
-/// Implementing the function as a visitor makes the necessity of supporting a new implementation of [DartType] visible at compile time.
-// TODO(dmitryas): Remove CoreTypes as the second argument when NullType is landed.
+/// Implementing the function as a visitor makes the necessity of supporting a
+/// new implementation of [DartType] visible at compile time.
+// TODO(dmitryas): Remove CoreTypes as the second argument when NullType is
+// landed.
 class _NullabilityConstructorUnwrapper
     implements DartTypeVisitor1<DartType, CoreTypes> {
   const _NullabilityConstructorUnwrapper();
 
   @override
   DartType defaultDartType(DartType node, CoreTypes coreTypes) {
-    throw new UnsupportedError(
-        "Unsupported operation: _NullabilityConstructorUnwrapper(${node.runtimeType})");
+    throw new UnsupportedError("Unsupported operation: "
+        "_NullabilityConstructorUnwrapper(${node.runtimeType})");
   }
 
   @override
@@ -1185,3 +1187,93 @@
     return super.visitTypeParameterType(node);
   }
 }
+
+/// Computes [type] as if declared without nullability markers.
+///
+/// For example, int? and int* are considered applications of the nullable and
+/// the legacy type constructors to type int correspondingly.
+/// [computeTypeWithoutNullabilityMarker] peels off these type constructors,
+/// returning the non-nullable version of type int.  In case of
+/// [TypeParameterType]s, the result may be either [Nullability.nonNullable] or
+/// [Nullability.undetermined], depending on the bound.
+DartType computeTypeWithoutNullabilityMarker(
+    DartType type, Library clientLibrary,
+    {DartType nullType}) {
+  assert(nullType != null);
+  if (type is TypeParameterType) {
+    if (type.promotedBound == null) {
+      // The default nullability for library is used when there are no
+      // nullability markers on the type.
+      return new TypeParameterType.withDefaultNullabilityForLibrary(
+          type.parameter, clientLibrary);
+    } else {
+      // Intersection types can't be arguments to the nullable and the legacy
+      // type constructors, so nothing can be peeled off.
+      return type;
+    }
+  } else if (type == nullType) {
+    return type;
+  } else {
+    // For most types, peeling off the nullability constructors means that
+    // they become non-nullable.
+    return type.withDeclaredNullability(Nullability.nonNullable);
+  }
+}
+
+/// Returns true if [type] is declared without nullability markers.
+///
+/// An example of the nullable type constructor application is T? where T is a
+/// type parameter.  Some examples of types declared without nullability markers
+/// are T% and S, where T and S are type parameters such that T extends Object?
+/// and S extends Object.
+bool isTypeParameterTypeWithoutNullabilityMarker(
+    TypeParameterType type, Library clientLibrary) {
+  // The default nullability for library is used when there are no nullability
+  // markers on the type.
+  return type.promotedBound == null &&
+      type.declaredNullability ==
+          new TypeParameterType.withDefaultNullabilityForLibrary(
+                  type.parameter, clientLibrary)
+              .declaredNullability;
+}
+
+/// Returns true if [type] is an application of the nullable type constructor.
+///
+/// A type is considered an application of the nullable type constructor if it
+/// was declared with the ? marker.  Some examples of such types are int?,
+/// String?, Object?, and T? where T is a type parameter.  Types dynamic, void,
+/// and Null are nullable, but aren't considered applications of the nullable
+/// type constructor.
+bool isNullableTypeConstructorApplication(DartType type, {DartType nullType}) {
+  assert(nullType != null);
+  return type.declaredNullability == Nullability.nullable &&
+      type is! DynamicType &&
+      type is! VoidType &&
+      type != nullType;
+}
+
+/// Returns true if [type] is an application of the legacy type constructor.
+///
+/// A type is considered an application of the legacy type constructor if it was
+/// declared within a legacy library and is not one of exempt types, such as
+/// dynamic or void.
+bool isLegacyTypeConstructorApplication(DartType type, Library clientLibrary) {
+  if (type is TypeParameterType) {
+    if (type.promotedBound == null) {
+      // The legacy nullability is considered an application of the legacy
+      // nullability constructor if it doesn't match the default nullability
+      // of the type-parameter type for the library.
+      return type.declaredNullability == Nullability.legacy &&
+          type.declaredNullability !=
+              new TypeParameterType.withDefaultNullabilityForLibrary(
+                      type.parameter, clientLibrary)
+                  .declaredNullability;
+    } else {
+      return false;
+    }
+  } else if (type is InvalidType) {
+    return false;
+  } else {
+    return type.declaredNullability == Nullability.legacy;
+  }
+}
diff --git a/tools/VERSION b/tools/VERSION
index 39715f5..15ebdcb 100644
--- a/tools/VERSION
+++ b/tools/VERSION
@@ -27,5 +27,5 @@
 MAJOR 2
 MINOR 11
 PATCH 0
-PRERELEASE 194
+PRERELEASE 195
 PRERELEASE_PATCH 0
\ No newline at end of file