diff --git a/pkg/_fe_analyzer_shared/lib/src/messages/codes_generated.dart b/pkg/_fe_analyzer_shared/lib/src/messages/codes_generated.dart
index 1564994..df9fd1e 100644
--- a/pkg/_fe_analyzer_shared/lib/src/messages/codes_generated.dart
+++ b/pkg/_fe_analyzer_shared/lib/src/messages/codes_generated.dart
@@ -5338,6 +5338,78 @@
 }
 
 // DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Template<Message Function(String name)>
+    templateInvalidGetterSetterTypeFieldContext =
+    const Template<Message Function(String name)>(
+        messageTemplate: r"""This is the declaration of the field '#name'.""",
+        withArguments: _withArgumentsInvalidGetterSetterTypeFieldContext);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Code<Message Function(String name)>
+    codeInvalidGetterSetterTypeFieldContext =
+    const Code<Message Function(String name)>(
+        "InvalidGetterSetterTypeFieldContext",
+        templateInvalidGetterSetterTypeFieldContext,
+        severity: Severity.context);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+Message _withArgumentsInvalidGetterSetterTypeFieldContext(String name) {
+  if (name.isEmpty) throw 'No name provided';
+  name = demangleMixinApplicationName(name);
+  return new Message(codeInvalidGetterSetterTypeFieldContext,
+      message: """This is the declaration of the field '${name}'.""",
+      arguments: {'name': name});
+}
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Template<Message Function(String name)>
+    templateInvalidGetterSetterTypeGetterContext =
+    const Template<Message Function(String name)>(
+        messageTemplate: r"""This is the declaration of the getter '#name'.""",
+        withArguments: _withArgumentsInvalidGetterSetterTypeGetterContext);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Code<Message Function(String name)>
+    codeInvalidGetterSetterTypeGetterContext =
+    const Code<Message Function(String name)>(
+        "InvalidGetterSetterTypeGetterContext",
+        templateInvalidGetterSetterTypeGetterContext,
+        severity: Severity.context);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+Message _withArgumentsInvalidGetterSetterTypeGetterContext(String name) {
+  if (name.isEmpty) throw 'No name provided';
+  name = demangleMixinApplicationName(name);
+  return new Message(codeInvalidGetterSetterTypeGetterContext,
+      message: """This is the declaration of the getter '${name}'.""",
+      arguments: {'name': name});
+}
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Template<Message Function(String name)>
+    templateInvalidGetterSetterTypeSetterContext =
+    const Template<Message Function(String name)>(
+        messageTemplate: r"""This is the declaration of the setter '#name'.""",
+        withArguments: _withArgumentsInvalidGetterSetterTypeSetterContext);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Code<Message Function(String name)>
+    codeInvalidGetterSetterTypeSetterContext =
+    const Code<Message Function(String name)>(
+        "InvalidGetterSetterTypeSetterContext",
+        templateInvalidGetterSetterTypeSetterContext,
+        severity: Severity.context);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+Message _withArgumentsInvalidGetterSetterTypeSetterContext(String name) {
+  if (name.isEmpty) throw 'No name provided';
+  name = demangleMixinApplicationName(name);
+  return new Message(codeInvalidGetterSetterTypeSetterContext,
+      message: """This is the declaration of the setter '${name}'.""",
+      arguments: {'name': name});
+}
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
 const Code<Null> codeInvalidHexEscape = messageInvalidHexEscape;
 
 // DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
diff --git a/pkg/analysis_server/lib/src/services/correction/bulk_fix_processor.dart b/pkg/analysis_server/lib/src/services/correction/bulk_fix_processor.dart
index dc26a16..5bd6ce2 100644
--- a/pkg/analysis_server/lib/src/services/correction/bulk_fix_processor.dart
+++ b/pkg/analysis_server/lib/src/services/correction/bulk_fix_processor.dart
@@ -63,6 +63,7 @@
 import 'package:analysis_server/src/services/linter/lint_names.dart';
 import 'package:analyzer/dart/analysis/results.dart';
 import 'package:analyzer/error/error.dart';
+import 'package:analyzer/source/error_processor.dart';
 import 'package:analyzer/src/error/codes.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer_plugin/utilities/change_builder/change_builder_core.dart';
@@ -356,6 +357,7 @@
   /// Use the change [builder] to create fixes for the diagnostics in the
   /// library associated with the analysis [result].
   Future<void> _fixErrorsInLibrary(ResolvedLibraryResult result) async {
+    var analysisOptions = result.session.analysisContext.analysisOptions;
     for (var unitResult in result.units) {
       final fixContext = DartFixContextImpl(
         workspace,
@@ -364,7 +366,11 @@
         (name) => [],
       );
       for (var error in unitResult.errors) {
-        await _fixSingleError(fixContext, unitResult, error);
+        var processor = ErrorProcessor.getProcessor(analysisOptions, error);
+        // Only fix errors not filtered out in analysis options.
+        if (processor == null || processor.severity != null) {
+          await _fixSingleError(fixContext, unitResult, error);
+        }
       }
     }
   }
diff --git a/pkg/analysis_server/test/edit/bulk_fixes_test.dart b/pkg/analysis_server/test/edit/bulk_fixes_test.dart
index c1d8b75..cf1c6c7 100644
--- a/pkg/analysis_server/test/edit/bulk_fixes_test.dart
+++ b/pkg/analysis_server/test/edit/bulk_fixes_test.dart
@@ -27,6 +27,12 @@
     expect(editedSource, expectedSource);
   }
 
+  Future<void> assertNoEdits() async {
+    await waitForTasksFinished();
+    var edits = await _getBulkEdits();
+    expect(edits, isEmpty);
+  }
+
   @override
   void setUp() {
     super.setUp();
@@ -52,6 +58,38 @@
 ''');
   }
 
+  Future<void> test_unnecessaryNew_ignoredInOptions() async {
+    createProject();
+    addAnalysisOptionsFile('''
+analyzer:
+  errors:
+    unnecessary_new: ignore
+linter:
+  rules:
+    - unnecessary_new
+''');
+    addTestFile('''
+class A {}
+A f() => new A();
+''');
+    await assertNoEdits();
+  }
+
+  Future<void> test_unnecessaryNew_ignoredInSource() async {
+    createProject();
+    addAnalysisOptionsFile('''
+linter:
+  rules:
+    - unnecessary_new
+''');
+    addTestFile('''
+class A {}
+//ignore: unnecessary_new
+A f() => new A();
+''');
+    await assertNoEdits();
+  }
+
   Future<List<SourceFileEdit>> _getBulkEdits() async {
     var request = EditBulkFixesParams([testFile]).toRequest('0');
     var response = await waitResponse(request);
diff --git a/pkg/analyzer/lib/src/dart/micro/resolve_file.dart b/pkg/analyzer/lib/src/dart/micro/resolve_file.dart
index 5216076..4b12e9d 100644
--- a/pkg/analyzer/lib/src/dart/micro/resolve_file.dart
+++ b/pkg/analyzer/lib/src/dart/micro/resolve_file.dart
@@ -462,10 +462,17 @@
   }) {
     YamlMap optionMap;
 
-    var optionsFile = performance.run('findOptionsFile', (_) {
-      var folder = resourceProvider.getFile(path).parent;
-      return _findOptionsFile(folder);
-    });
+    var separator = resourceProvider.pathContext.separator;
+    var isThirdParty =
+        path.contains('${separator}third_party${separator}dart$separator');
+
+    File optionsFile;
+    if (!isThirdParty) {
+      optionsFile = performance.run('findOptionsFile', (_) {
+        var folder = resourceProvider.getFile(path).parent;
+        return _findOptionsFile(folder);
+      });
+    }
 
     if (optionsFile != null) {
       performance.run('getOptionsFromFile', (_) {
@@ -479,9 +486,7 @@
     } else {
       var source = performance.run('defaultOptions', (_) {
         if (workspace is WorkspaceWithDefaultAnalysisOptions) {
-          var separator = resourceProvider.pathContext.separator;
-          if (path
-              .contains('${separator}third_party${separator}dart$separator')) {
+          if (isThirdParty) {
             return sourceFactory.forUri(
               WorkspaceWithDefaultAnalysisOptions.thirdPartyUri,
             );
diff --git a/pkg/analyzer/test/src/dart/micro/simple_file_resolver_test.dart b/pkg/analyzer/test/src/dart/micro/simple_file_resolver_test.dart
index f096933..ec169b2 100644
--- a/pkg/analyzer/test/src/dart/micro/simple_file_resolver_test.dart
+++ b/pkg/analyzer/test/src/dart/micro/simple_file_resolver_test.dart
@@ -312,6 +312,13 @@
     implicit-casts: false
 ''');
 
+    newFile('/workspace/thid_party/dart/aaa/analysis_options.yaml',
+        content: r'''
+analyzer:
+  strong-mode:
+    implicit-casts: true
+''');
+
     var aPath = convertPath('/workspace/third_party/dart/aaa/lib/a.dart');
     await assertErrorsInFile(aPath, r'''
 num a = 0;
diff --git a/pkg/dev_compiler/bin/dartdevc.dart b/pkg/dev_compiler/bin/dartdevc.dart
index 68246e3..baf9c9a 100755
--- a/pkg/dev_compiler/bin/dartdevc.dart
+++ b/pkg/dev_compiler/bin/dartdevc.dart
@@ -30,17 +30,20 @@
   } else if (parsedArgs.isBatch) {
     await runBatch(parsedArgs);
   } else if (parsedArgs.isExpressionCompiler) {
-    ExpressionCompilerWorker worker;
     if (sendPort != null) {
       var receivePort = ReceivePort();
       sendPort.send(receivePort.sendPort);
-      worker = await ExpressionCompilerWorker.createFromArgs(parsedArgs.rest,
+      var worker = await ExpressionCompilerWorker.createFromArgs(
+          parsedArgs.rest,
           requestStream: receivePort.cast<Map<String, dynamic>>(),
           sendResponse: sendPort.send);
+      await worker.start();
+      receivePort.close();
     } else {
-      worker = await ExpressionCompilerWorker.createFromArgs(parsedArgs.rest);
+      var worker =
+          await ExpressionCompilerWorker.createFromArgs(parsedArgs.rest);
+      await worker.start();
     }
-    await worker.start();
   } else {
     var result = await compile(parsedArgs);
     exitCode = result.exitCode;
diff --git a/pkg/dev_compiler/lib/src/kernel/compiler.dart b/pkg/dev_compiler/lib/src/kernel/compiler.dart
index cd7ebd3..7e7566e 100644
--- a/pkg/dev_compiler/lib/src/kernel/compiler.dart
+++ b/pkg/dev_compiler/lib/src/kernel/compiler.dart
@@ -882,21 +882,16 @@
     var savedTopLevelClass = _classEmittingExtends;
     _classEmittingExtends = c;
 
-    // Refers to 'S' in `class C extends S`. Set this to null to avoid
-    // referencing deferred supertypes in _emitClassConstructor's JS output.
-    js_ast.Expression baseClass;
-
+    // Unroll mixins.
     if (shouldDefer(supertype)) {
       deferredSupertypes.add(runtimeStatement('setBaseClass(#, #)', [
         getBaseClass(isMixinAliasClass(c) ? 0 : mixinApplications.length),
         emitDeferredType(supertype),
       ]));
-      // Refers to 'supertype' without any type arguments.
       supertype =
           _coreTypes.rawType(supertype.classNode, _currentLibrary.nonNullable);
-    } else {
-      baseClass = emitClassRef(supertype);
     }
+    var baseClass = emitClassRef(supertype);
 
     if (isMixinAliasClass(c)) {
       // Given `class C = Object with M [implements I1, I2 ...];`
diff --git a/pkg/dev_compiler/lib/src/kernel/expression_compiler_worker.dart b/pkg/dev_compiler/lib/src/kernel/expression_compiler_worker.dart
index 85aa859..a1b995c 100644
--- a/pkg/dev_compiler/lib/src/kernel/expression_compiler_worker.dart
+++ b/pkg/dev_compiler/lib/src/kernel/expression_compiler_worker.dart
@@ -213,6 +213,7 @@
     await for (var request in requestStream) {
       try {
         var command = request['command'] as String;
+        if (command == 'Shutdown') break;
         switch (command) {
           case 'UpdateDeps':
             sendResponse(
@@ -234,6 +235,7 @@
         });
       }
     }
+    _processedOptions.ticker.logMs('Stopped expression compiler worker.');
   }
 
   /// Handles a `CompileExpression` request.
diff --git a/pkg/front_end/lib/src/fasta/builder/field_builder.dart b/pkg/front_end/lib/src/fasta/builder/field_builder.dart
index f3bf41e..429d5f1 100644
--- a/pkg/front_end/lib/src/fasta/builder/field_builder.dart
+++ b/pkg/front_end/lib/src/fasta/builder/field_builder.dart
@@ -713,6 +713,11 @@
 
   @override
   bool get isFunction => false;
+
+  @override
+  bool isSameDeclaration(ClassMember other) {
+    return other is SourceFieldMember && memberBuilder == other.memberBuilder;
+  }
 }
 
 abstract class AbstractLateFieldEncoding implements FieldEncoding {
@@ -1057,13 +1062,16 @@
   @override
   List<ClassMember> getLocalMembers(SourceFieldBuilder fieldBuilder) {
     List<ClassMember> list = <ClassMember>[
-      new _SynthesizedFieldClassMember(fieldBuilder, field,
+      new _SynthesizedFieldClassMember(
+          fieldBuilder, field, _SynthesizedFieldMemberKind.LateField,
           isInternalImplementation: true),
       new _SynthesizedFieldClassMember(fieldBuilder, _lateGetter,
+          _SynthesizedFieldMemberKind.LateGetterSetter,
           isInternalImplementation: false)
     ];
     if (_lateIsSetField != null) {
-      list.add(new _SynthesizedFieldClassMember(fieldBuilder, _lateIsSetField,
+      list.add(new _SynthesizedFieldClassMember(
+          fieldBuilder, _lateIsSetField, _SynthesizedFieldMemberKind.LateIsSet,
           isInternalImplementation: true));
     }
     return list;
@@ -1071,13 +1079,19 @@
 
   @override
   List<ClassMember> getLocalSetters(SourceFieldBuilder fieldBuilder) {
-    List<ClassMember> list = <ClassMember>[];
+    List<ClassMember> list = <ClassMember>[
+      new _SynthesizedFieldClassMember(
+          fieldBuilder, field, _SynthesizedFieldMemberKind.LateField,
+          forSetter: true, isInternalImplementation: true),
+    ];
     if (_lateIsSetField != null) {
-      list.add(new _SynthesizedFieldClassMember(fieldBuilder, _lateIsSetField,
+      list.add(new _SynthesizedFieldClassMember(
+          fieldBuilder, _lateIsSetField, _SynthesizedFieldMemberKind.LateIsSet,
           forSetter: true, isInternalImplementation: true));
     }
     if (_lateSetter != null) {
       list.add(new _SynthesizedFieldClassMember(fieldBuilder, _lateSetter,
+          _SynthesizedFieldMemberKind.LateGetterSetter,
           forSetter: true, isInternalImplementation: false));
     }
     return list;
@@ -1274,6 +1288,7 @@
 
 class _SynthesizedFieldClassMember implements ClassMember {
   final SourceFieldBuilder fieldBuilder;
+  final _SynthesizedFieldMemberKind _kind;
 
   final Member _member;
 
@@ -1283,7 +1298,7 @@
   @override
   final bool isInternalImplementation;
 
-  _SynthesizedFieldClassMember(this.fieldBuilder, this._member,
+  _SynthesizedFieldClassMember(this.fieldBuilder, this._member, this._kind,
       {this.forSetter: false, this.isInternalImplementation})
       : assert(isInternalImplementation != null);
 
@@ -1415,8 +1430,16 @@
   }
 
   @override
-  String toString() =>
-      '_ClassMember($fieldBuilder,$_member,forSetter=${forSetter})';
+  bool isSameDeclaration(ClassMember other) {
+    if (identical(this, other)) return true;
+    return other is _SynthesizedFieldClassMember &&
+        fieldBuilder == other.fieldBuilder &&
+        _kind == other._kind;
+  }
+
+  @override
+  String toString() => '_SynthesizedFieldClassMember('
+      '$fieldBuilder,$_member,$_kind,forSetter=${forSetter})';
 }
 
 class AbstractOrExternalFieldEncoding implements FieldEncoding {
@@ -1584,6 +1607,7 @@
   List<ClassMember> getLocalMembers(SourceFieldBuilder fieldBuilder) =>
       <ClassMember>[
         new _SynthesizedFieldClassMember(fieldBuilder, _getter,
+            _SynthesizedFieldMemberKind.AbstractExternalGetterSetter,
             forSetter: false, isInternalImplementation: false)
       ];
 
@@ -1592,7 +1616,22 @@
       _setter != null
           ? <ClassMember>[
               new _SynthesizedFieldClassMember(fieldBuilder, _setter,
+                  _SynthesizedFieldMemberKind.AbstractExternalGetterSetter,
                   forSetter: true, isInternalImplementation: false)
             ]
           : const <ClassMember>[];
 }
+
+enum _SynthesizedFieldMemberKind {
+  /// A `isSet` field used for late lowering.
+  LateIsSet,
+
+  /// A field used for the value of a late lowered field.
+  LateField,
+
+  /// A getter or setter used for late lowering.
+  LateGetterSetter,
+
+  /// A getter or setter used for abstract or external fields.
+  AbstractExternalGetterSetter,
+}
diff --git a/pkg/front_end/lib/src/fasta/builder/procedure_builder.dart b/pkg/front_end/lib/src/fasta/builder/procedure_builder.dart
index 75c8ba1..b42e61e 100644
--- a/pkg/front_end/lib/src/fasta/builder/procedure_builder.dart
+++ b/pkg/front_end/lib/src/fasta/builder/procedure_builder.dart
@@ -614,6 +614,12 @@
 
   @override
   bool get isFunction => !isProperty;
+
+  @override
+  bool isSameDeclaration(ClassMember other) {
+    return other is SourceProcedureMember &&
+        memberBuilder == other.memberBuilder;
+  }
 }
 
 class RedirectingFactoryBuilder extends ProcedureBuilderImpl {
diff --git a/pkg/front_end/lib/src/fasta/dill/dill_member_builder.dart b/pkg/front_end/lib/src/fasta/dill/dill_member_builder.dart
index ca51796..b34c24f 100644
--- a/pkg/front_end/lib/src/fasta/dill/dill_member_builder.dart
+++ b/pkg/front_end/lib/src/fasta/dill/dill_member_builder.dart
@@ -191,6 +191,11 @@
     // Do nothing; this is only for source members.
   }
 
+  @override
+  bool isSameDeclaration(ClassMember other) {
+    return other is DillClassMember && memberBuilder == other.memberBuilder;
+  }
+
   String toString() => 'DillClassMember($memberBuilder,forSetter=${forSetter})';
 }
 
diff --git a/pkg/front_end/lib/src/fasta/fasta_codes_cfe_generated.dart b/pkg/front_end/lib/src/fasta/fasta_codes_cfe_generated.dart
index 480cc47..3e928df 100644
--- a/pkg/front_end/lib/src/fasta/fasta_codes_cfe_generated.dart
+++ b/pkg/front_end/lib/src/fasta/fasta_codes_cfe_generated.dart
@@ -2042,6 +2042,690 @@
 
 // DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
 const Template<
+        Message Function(DartType _type, String name, DartType _type2,
+            String name2, bool isNonNullableByDefault)>
+    templateInvalidGetterSetterType = const Template<
+            Message Function(DartType _type, String name, DartType _type2,
+                String name2, bool isNonNullableByDefault)>(
+        messageTemplate:
+            r"""The type '#type' of the getter '#name' is not a subtype of the type '#type2' of the setter '#name2'.""",
+        withArguments: _withArgumentsInvalidGetterSetterType);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Code<
+    Message Function(DartType _type, String name, DartType _type2, String name2,
+        bool isNonNullableByDefault)> codeInvalidGetterSetterType = const Code<
+    Message Function(DartType _type, String name, DartType _type2, String name2,
+        bool isNonNullableByDefault)>(
+  "InvalidGetterSetterType",
+  templateInvalidGetterSetterType,
+);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+Message _withArgumentsInvalidGetterSetterType(DartType _type, String name,
+    DartType _type2, String name2, bool isNonNullableByDefault) {
+  TypeLabeler labeler = new TypeLabeler(isNonNullableByDefault);
+  List<Object> typeParts = labeler.labelType(_type);
+  if (name.isEmpty) throw 'No name provided';
+  name = demangleMixinApplicationName(name);
+  List<Object> type2Parts = labeler.labelType(_type2);
+  if (name2.isEmpty) throw 'No name provided';
+  name2 = demangleMixinApplicationName(name2);
+  String type = typeParts.join();
+  String type2 = type2Parts.join();
+  return new Message(codeInvalidGetterSetterType,
+      message:
+          """The type '${type}' of the getter '${name}' is not a subtype of the type '${type2}' of the setter '${name2}'.""" +
+              labeler.originMessages,
+      arguments: {
+        'type': _type,
+        'name': name,
+        'type2': _type2,
+        'name2': name2
+      });
+}
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Template<
+        Message Function(DartType _type, String name, DartType _type2,
+            String name2, bool isNonNullableByDefault)>
+    templateInvalidGetterSetterTypeBothInheritedField = const Template<
+            Message Function(DartType _type, String name, DartType _type2,
+                String name2, bool isNonNullableByDefault)>(
+        messageTemplate:
+            r"""The type '#type' of the inherited field '#name' is not a subtype of the type '#type2' of the inherited setter '#name2'.""",
+        withArguments: _withArgumentsInvalidGetterSetterTypeBothInheritedField);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Code<
+        Message Function(DartType _type, String name, DartType _type2,
+            String name2, bool isNonNullableByDefault)>
+    codeInvalidGetterSetterTypeBothInheritedField = const Code<
+        Message Function(DartType _type, String name, DartType _type2,
+            String name2, bool isNonNullableByDefault)>(
+  "InvalidGetterSetterTypeBothInheritedField",
+  templateInvalidGetterSetterTypeBothInheritedField,
+);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+Message _withArgumentsInvalidGetterSetterTypeBothInheritedField(DartType _type,
+    String name, DartType _type2, String name2, bool isNonNullableByDefault) {
+  TypeLabeler labeler = new TypeLabeler(isNonNullableByDefault);
+  List<Object> typeParts = labeler.labelType(_type);
+  if (name.isEmpty) throw 'No name provided';
+  name = demangleMixinApplicationName(name);
+  List<Object> type2Parts = labeler.labelType(_type2);
+  if (name2.isEmpty) throw 'No name provided';
+  name2 = demangleMixinApplicationName(name2);
+  String type = typeParts.join();
+  String type2 = type2Parts.join();
+  return new Message(codeInvalidGetterSetterTypeBothInheritedField,
+      message:
+          """The type '${type}' of the inherited field '${name}' is not a subtype of the type '${type2}' of the inherited setter '${name2}'.""" +
+              labeler.originMessages,
+      arguments: {
+        'type': _type,
+        'name': name,
+        'type2': _type2,
+        'name2': name2
+      });
+}
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Template<
+        Message Function(DartType _type, String name, DartType _type2,
+            String name2, bool isNonNullableByDefault)>
+    templateInvalidGetterSetterTypeBothInheritedFieldLegacy = const Template<
+            Message Function(DartType _type, String name, DartType _type2,
+                String name2, bool isNonNullableByDefault)>(
+        messageTemplate:
+            r"""The type '#type' of the inherited field '#name' is not assignable to the type '#type2' of the inherited setter '#name2'.""",
+        withArguments:
+            _withArgumentsInvalidGetterSetterTypeBothInheritedFieldLegacy);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Code<
+        Message Function(DartType _type, String name, DartType _type2,
+            String name2, bool isNonNullableByDefault)>
+    codeInvalidGetterSetterTypeBothInheritedFieldLegacy = const Code<
+        Message Function(DartType _type, String name, DartType _type2,
+            String name2, bool isNonNullableByDefault)>(
+  "InvalidGetterSetterTypeBothInheritedFieldLegacy",
+  templateInvalidGetterSetterTypeBothInheritedFieldLegacy,
+);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+Message _withArgumentsInvalidGetterSetterTypeBothInheritedFieldLegacy(
+    DartType _type,
+    String name,
+    DartType _type2,
+    String name2,
+    bool isNonNullableByDefault) {
+  TypeLabeler labeler = new TypeLabeler(isNonNullableByDefault);
+  List<Object> typeParts = labeler.labelType(_type);
+  if (name.isEmpty) throw 'No name provided';
+  name = demangleMixinApplicationName(name);
+  List<Object> type2Parts = labeler.labelType(_type2);
+  if (name2.isEmpty) throw 'No name provided';
+  name2 = demangleMixinApplicationName(name2);
+  String type = typeParts.join();
+  String type2 = type2Parts.join();
+  return new Message(codeInvalidGetterSetterTypeBothInheritedFieldLegacy,
+      message:
+          """The type '${type}' of the inherited field '${name}' is not assignable to the type '${type2}' of the inherited setter '${name2}'.""" +
+              labeler.originMessages,
+      arguments: {
+        'type': _type,
+        'name': name,
+        'type2': _type2,
+        'name2': name2
+      });
+}
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Template<
+        Message Function(DartType _type, String name, DartType _type2,
+            String name2, bool isNonNullableByDefault)>
+    templateInvalidGetterSetterTypeBothInheritedGetter = const Template<
+            Message Function(DartType _type, String name, DartType _type2,
+                String name2, bool isNonNullableByDefault)>(
+        messageTemplate:
+            r"""The type '#type' of the inherited getter '#name' is not a subtype of the type '#type2' of the inherited setter '#name2'.""",
+        withArguments:
+            _withArgumentsInvalidGetterSetterTypeBothInheritedGetter);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Code<
+        Message Function(DartType _type, String name, DartType _type2,
+            String name2, bool isNonNullableByDefault)>
+    codeInvalidGetterSetterTypeBothInheritedGetter = const Code<
+        Message Function(DartType _type, String name, DartType _type2,
+            String name2, bool isNonNullableByDefault)>(
+  "InvalidGetterSetterTypeBothInheritedGetter",
+  templateInvalidGetterSetterTypeBothInheritedGetter,
+);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+Message _withArgumentsInvalidGetterSetterTypeBothInheritedGetter(DartType _type,
+    String name, DartType _type2, String name2, bool isNonNullableByDefault) {
+  TypeLabeler labeler = new TypeLabeler(isNonNullableByDefault);
+  List<Object> typeParts = labeler.labelType(_type);
+  if (name.isEmpty) throw 'No name provided';
+  name = demangleMixinApplicationName(name);
+  List<Object> type2Parts = labeler.labelType(_type2);
+  if (name2.isEmpty) throw 'No name provided';
+  name2 = demangleMixinApplicationName(name2);
+  String type = typeParts.join();
+  String type2 = type2Parts.join();
+  return new Message(codeInvalidGetterSetterTypeBothInheritedGetter,
+      message:
+          """The type '${type}' of the inherited getter '${name}' is not a subtype of the type '${type2}' of the inherited setter '${name2}'.""" +
+              labeler.originMessages,
+      arguments: {
+        'type': _type,
+        'name': name,
+        'type2': _type2,
+        'name2': name2
+      });
+}
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Template<
+        Message Function(DartType _type, String name, DartType _type2,
+            String name2, bool isNonNullableByDefault)>
+    templateInvalidGetterSetterTypeBothInheritedGetterLegacy = const Template<
+            Message Function(DartType _type, String name, DartType _type2,
+                String name2, bool isNonNullableByDefault)>(
+        messageTemplate:
+            r"""The type '#type' of the inherited getter '#name' is not assignable to the type '#type2' of the inherited setter '#name2'.""",
+        withArguments:
+            _withArgumentsInvalidGetterSetterTypeBothInheritedGetterLegacy);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Code<
+        Message Function(DartType _type, String name, DartType _type2,
+            String name2, bool isNonNullableByDefault)>
+    codeInvalidGetterSetterTypeBothInheritedGetterLegacy = const Code<
+        Message Function(DartType _type, String name, DartType _type2,
+            String name2, bool isNonNullableByDefault)>(
+  "InvalidGetterSetterTypeBothInheritedGetterLegacy",
+  templateInvalidGetterSetterTypeBothInheritedGetterLegacy,
+);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+Message _withArgumentsInvalidGetterSetterTypeBothInheritedGetterLegacy(
+    DartType _type,
+    String name,
+    DartType _type2,
+    String name2,
+    bool isNonNullableByDefault) {
+  TypeLabeler labeler = new TypeLabeler(isNonNullableByDefault);
+  List<Object> typeParts = labeler.labelType(_type);
+  if (name.isEmpty) throw 'No name provided';
+  name = demangleMixinApplicationName(name);
+  List<Object> type2Parts = labeler.labelType(_type2);
+  if (name2.isEmpty) throw 'No name provided';
+  name2 = demangleMixinApplicationName(name2);
+  String type = typeParts.join();
+  String type2 = type2Parts.join();
+  return new Message(codeInvalidGetterSetterTypeBothInheritedGetterLegacy,
+      message:
+          """The type '${type}' of the inherited getter '${name}' is not assignable to the type '${type2}' of the inherited setter '${name2}'.""" +
+              labeler.originMessages,
+      arguments: {
+        'type': _type,
+        'name': name,
+        'type2': _type2,
+        'name2': name2
+      });
+}
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Template<
+        Message Function(DartType _type, String name, DartType _type2,
+            String name2, bool isNonNullableByDefault)>
+    templateInvalidGetterSetterTypeFieldInherited = const Template<
+            Message Function(DartType _type, String name, DartType _type2,
+                String name2, bool isNonNullableByDefault)>(
+        messageTemplate:
+            r"""The type '#type' of the inherited field '#name' is not a subtype of the type '#type2' of the setter '#name2'.""",
+        withArguments: _withArgumentsInvalidGetterSetterTypeFieldInherited);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Code<
+        Message Function(DartType _type, String name, DartType _type2,
+            String name2, bool isNonNullableByDefault)>
+    codeInvalidGetterSetterTypeFieldInherited = const Code<
+        Message Function(DartType _type, String name, DartType _type2,
+            String name2, bool isNonNullableByDefault)>(
+  "InvalidGetterSetterTypeFieldInherited",
+  templateInvalidGetterSetterTypeFieldInherited,
+);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+Message _withArgumentsInvalidGetterSetterTypeFieldInherited(DartType _type,
+    String name, DartType _type2, String name2, bool isNonNullableByDefault) {
+  TypeLabeler labeler = new TypeLabeler(isNonNullableByDefault);
+  List<Object> typeParts = labeler.labelType(_type);
+  if (name.isEmpty) throw 'No name provided';
+  name = demangleMixinApplicationName(name);
+  List<Object> type2Parts = labeler.labelType(_type2);
+  if (name2.isEmpty) throw 'No name provided';
+  name2 = demangleMixinApplicationName(name2);
+  String type = typeParts.join();
+  String type2 = type2Parts.join();
+  return new Message(codeInvalidGetterSetterTypeFieldInherited,
+      message:
+          """The type '${type}' of the inherited field '${name}' is not a subtype of the type '${type2}' of the setter '${name2}'.""" +
+              labeler.originMessages,
+      arguments: {
+        'type': _type,
+        'name': name,
+        'type2': _type2,
+        'name2': name2
+      });
+}
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Template<
+        Message Function(DartType _type, String name, DartType _type2,
+            String name2, bool isNonNullableByDefault)>
+    templateInvalidGetterSetterTypeFieldInheritedLegacy = const Template<
+            Message Function(DartType _type, String name, DartType _type2,
+                String name2, bool isNonNullableByDefault)>(
+        messageTemplate:
+            r"""The type '#type' of the inherited field '#name' is not assignable to the type '#type2' of the setter '#name2'.""",
+        withArguments:
+            _withArgumentsInvalidGetterSetterTypeFieldInheritedLegacy);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Code<
+        Message Function(DartType _type, String name, DartType _type2,
+            String name2, bool isNonNullableByDefault)>
+    codeInvalidGetterSetterTypeFieldInheritedLegacy = const Code<
+        Message Function(DartType _type, String name, DartType _type2,
+            String name2, bool isNonNullableByDefault)>(
+  "InvalidGetterSetterTypeFieldInheritedLegacy",
+  templateInvalidGetterSetterTypeFieldInheritedLegacy,
+);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+Message _withArgumentsInvalidGetterSetterTypeFieldInheritedLegacy(
+    DartType _type,
+    String name,
+    DartType _type2,
+    String name2,
+    bool isNonNullableByDefault) {
+  TypeLabeler labeler = new TypeLabeler(isNonNullableByDefault);
+  List<Object> typeParts = labeler.labelType(_type);
+  if (name.isEmpty) throw 'No name provided';
+  name = demangleMixinApplicationName(name);
+  List<Object> type2Parts = labeler.labelType(_type2);
+  if (name2.isEmpty) throw 'No name provided';
+  name2 = demangleMixinApplicationName(name2);
+  String type = typeParts.join();
+  String type2 = type2Parts.join();
+  return new Message(codeInvalidGetterSetterTypeFieldInheritedLegacy,
+      message:
+          """The type '${type}' of the inherited field '${name}' is not assignable to the type '${type2}' of the setter '${name2}'.""" +
+              labeler.originMessages,
+      arguments: {
+        'type': _type,
+        'name': name,
+        'type2': _type2,
+        'name2': name2
+      });
+}
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Template<
+        Message Function(DartType _type, String name, DartType _type2,
+            String name2, bool isNonNullableByDefault)>
+    templateInvalidGetterSetterTypeGetterInherited = const Template<
+            Message Function(DartType _type, String name, DartType _type2,
+                String name2, bool isNonNullableByDefault)>(
+        messageTemplate:
+            r"""The type '#type' of the inherited getter '#name' is not a subtype of the type '#type2' of the setter '#name2'.""",
+        withArguments: _withArgumentsInvalidGetterSetterTypeGetterInherited);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Code<
+        Message Function(DartType _type, String name, DartType _type2,
+            String name2, bool isNonNullableByDefault)>
+    codeInvalidGetterSetterTypeGetterInherited = const Code<
+        Message Function(DartType _type, String name, DartType _type2,
+            String name2, bool isNonNullableByDefault)>(
+  "InvalidGetterSetterTypeGetterInherited",
+  templateInvalidGetterSetterTypeGetterInherited,
+);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+Message _withArgumentsInvalidGetterSetterTypeGetterInherited(DartType _type,
+    String name, DartType _type2, String name2, bool isNonNullableByDefault) {
+  TypeLabeler labeler = new TypeLabeler(isNonNullableByDefault);
+  List<Object> typeParts = labeler.labelType(_type);
+  if (name.isEmpty) throw 'No name provided';
+  name = demangleMixinApplicationName(name);
+  List<Object> type2Parts = labeler.labelType(_type2);
+  if (name2.isEmpty) throw 'No name provided';
+  name2 = demangleMixinApplicationName(name2);
+  String type = typeParts.join();
+  String type2 = type2Parts.join();
+  return new Message(codeInvalidGetterSetterTypeGetterInherited,
+      message:
+          """The type '${type}' of the inherited getter '${name}' is not a subtype of the type '${type2}' of the setter '${name2}'.""" +
+              labeler.originMessages,
+      arguments: {
+        'type': _type,
+        'name': name,
+        'type2': _type2,
+        'name2': name2
+      });
+}
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Template<
+        Message Function(DartType _type, String name, DartType _type2,
+            String name2, bool isNonNullableByDefault)>
+    templateInvalidGetterSetterTypeGetterInheritedLegacy = const Template<
+            Message Function(DartType _type, String name, DartType _type2,
+                String name2, bool isNonNullableByDefault)>(
+        messageTemplate:
+            r"""The type '#type' of the inherited getter '#name' is not assignable to the type '#type2' of the setter '#name2'.""",
+        withArguments:
+            _withArgumentsInvalidGetterSetterTypeGetterInheritedLegacy);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Code<
+        Message Function(DartType _type, String name, DartType _type2,
+            String name2, bool isNonNullableByDefault)>
+    codeInvalidGetterSetterTypeGetterInheritedLegacy = const Code<
+        Message Function(DartType _type, String name, DartType _type2,
+            String name2, bool isNonNullableByDefault)>(
+  "InvalidGetterSetterTypeGetterInheritedLegacy",
+  templateInvalidGetterSetterTypeGetterInheritedLegacy,
+);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+Message _withArgumentsInvalidGetterSetterTypeGetterInheritedLegacy(
+    DartType _type,
+    String name,
+    DartType _type2,
+    String name2,
+    bool isNonNullableByDefault) {
+  TypeLabeler labeler = new TypeLabeler(isNonNullableByDefault);
+  List<Object> typeParts = labeler.labelType(_type);
+  if (name.isEmpty) throw 'No name provided';
+  name = demangleMixinApplicationName(name);
+  List<Object> type2Parts = labeler.labelType(_type2);
+  if (name2.isEmpty) throw 'No name provided';
+  name2 = demangleMixinApplicationName(name2);
+  String type = typeParts.join();
+  String type2 = type2Parts.join();
+  return new Message(codeInvalidGetterSetterTypeGetterInheritedLegacy,
+      message:
+          """The type '${type}' of the inherited getter '${name}' is not assignable to the type '${type2}' of the setter '${name2}'.""" +
+              labeler.originMessages,
+      arguments: {
+        'type': _type,
+        'name': name,
+        'type2': _type2,
+        'name2': name2
+      });
+}
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Template<
+        Message Function(DartType _type, String name, DartType _type2,
+            String name2, bool isNonNullableByDefault)>
+    templateInvalidGetterSetterTypeLegacy = const Template<
+            Message Function(DartType _type, String name, DartType _type2,
+                String name2, bool isNonNullableByDefault)>(
+        messageTemplate:
+            r"""The type '#type' of the getter '#name' is not assignable to the type '#type2' of the setter '#name2'.""",
+        withArguments: _withArgumentsInvalidGetterSetterTypeLegacy);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Code<
+        Message Function(DartType _type, String name, DartType _type2,
+            String name2, bool isNonNullableByDefault)>
+    codeInvalidGetterSetterTypeLegacy = const Code<
+        Message Function(DartType _type, String name, DartType _type2,
+            String name2, bool isNonNullableByDefault)>(
+  "InvalidGetterSetterTypeLegacy",
+  templateInvalidGetterSetterTypeLegacy,
+);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+Message _withArgumentsInvalidGetterSetterTypeLegacy(DartType _type, String name,
+    DartType _type2, String name2, bool isNonNullableByDefault) {
+  TypeLabeler labeler = new TypeLabeler(isNonNullableByDefault);
+  List<Object> typeParts = labeler.labelType(_type);
+  if (name.isEmpty) throw 'No name provided';
+  name = demangleMixinApplicationName(name);
+  List<Object> type2Parts = labeler.labelType(_type2);
+  if (name2.isEmpty) throw 'No name provided';
+  name2 = demangleMixinApplicationName(name2);
+  String type = typeParts.join();
+  String type2 = type2Parts.join();
+  return new Message(codeInvalidGetterSetterTypeLegacy,
+      message:
+          """The type '${type}' of the getter '${name}' is not assignable to the type '${type2}' of the setter '${name2}'.""" +
+              labeler.originMessages,
+      arguments: {
+        'type': _type,
+        'name': name,
+        'type2': _type2,
+        'name2': name2
+      });
+}
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Template<
+        Message Function(DartType _type, String name, DartType _type2,
+            String name2, bool isNonNullableByDefault)>
+    templateInvalidGetterSetterTypeSetterInheritedField = const Template<
+            Message Function(DartType _type, String name, DartType _type2,
+                String name2, bool isNonNullableByDefault)>(
+        messageTemplate:
+            r"""The type '#type' of the field '#name' is not a subtype of the type '#type2' of the inherited setter '#name2'.""",
+        withArguments:
+            _withArgumentsInvalidGetterSetterTypeSetterInheritedField);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Code<
+        Message Function(DartType _type, String name, DartType _type2,
+            String name2, bool isNonNullableByDefault)>
+    codeInvalidGetterSetterTypeSetterInheritedField = const Code<
+        Message Function(DartType _type, String name, DartType _type2,
+            String name2, bool isNonNullableByDefault)>(
+  "InvalidGetterSetterTypeSetterInheritedField",
+  templateInvalidGetterSetterTypeSetterInheritedField,
+);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+Message _withArgumentsInvalidGetterSetterTypeSetterInheritedField(
+    DartType _type,
+    String name,
+    DartType _type2,
+    String name2,
+    bool isNonNullableByDefault) {
+  TypeLabeler labeler = new TypeLabeler(isNonNullableByDefault);
+  List<Object> typeParts = labeler.labelType(_type);
+  if (name.isEmpty) throw 'No name provided';
+  name = demangleMixinApplicationName(name);
+  List<Object> type2Parts = labeler.labelType(_type2);
+  if (name2.isEmpty) throw 'No name provided';
+  name2 = demangleMixinApplicationName(name2);
+  String type = typeParts.join();
+  String type2 = type2Parts.join();
+  return new Message(codeInvalidGetterSetterTypeSetterInheritedField,
+      message:
+          """The type '${type}' of the field '${name}' is not a subtype of the type '${type2}' of the inherited setter '${name2}'.""" +
+              labeler.originMessages,
+      arguments: {
+        'type': _type,
+        'name': name,
+        'type2': _type2,
+        'name2': name2
+      });
+}
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Template<
+        Message Function(DartType _type, String name, DartType _type2,
+            String name2, bool isNonNullableByDefault)>
+    templateInvalidGetterSetterTypeSetterInheritedFieldLegacy = const Template<
+            Message Function(DartType _type, String name, DartType _type2,
+                String name2, bool isNonNullableByDefault)>(
+        messageTemplate:
+            r"""The type '#type' of the field '#name' is not assignable to the type '#type2' of the inherited setter '#name2'.""",
+        withArguments:
+            _withArgumentsInvalidGetterSetterTypeSetterInheritedFieldLegacy);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Code<
+        Message Function(DartType _type, String name, DartType _type2,
+            String name2, bool isNonNullableByDefault)>
+    codeInvalidGetterSetterTypeSetterInheritedFieldLegacy = const Code<
+        Message Function(DartType _type, String name, DartType _type2,
+            String name2, bool isNonNullableByDefault)>(
+  "InvalidGetterSetterTypeSetterInheritedFieldLegacy",
+  templateInvalidGetterSetterTypeSetterInheritedFieldLegacy,
+);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+Message _withArgumentsInvalidGetterSetterTypeSetterInheritedFieldLegacy(
+    DartType _type,
+    String name,
+    DartType _type2,
+    String name2,
+    bool isNonNullableByDefault) {
+  TypeLabeler labeler = new TypeLabeler(isNonNullableByDefault);
+  List<Object> typeParts = labeler.labelType(_type);
+  if (name.isEmpty) throw 'No name provided';
+  name = demangleMixinApplicationName(name);
+  List<Object> type2Parts = labeler.labelType(_type2);
+  if (name2.isEmpty) throw 'No name provided';
+  name2 = demangleMixinApplicationName(name2);
+  String type = typeParts.join();
+  String type2 = type2Parts.join();
+  return new Message(codeInvalidGetterSetterTypeSetterInheritedFieldLegacy,
+      message:
+          """The type '${type}' of the field '${name}' is not assignable to the type '${type2}' of the inherited setter '${name2}'.""" +
+              labeler.originMessages,
+      arguments: {
+        'type': _type,
+        'name': name,
+        'type2': _type2,
+        'name2': name2
+      });
+}
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Template<
+        Message Function(DartType _type, String name, DartType _type2,
+            String name2, bool isNonNullableByDefault)>
+    templateInvalidGetterSetterTypeSetterInheritedGetter = const Template<
+            Message Function(DartType _type, String name, DartType _type2,
+                String name2, bool isNonNullableByDefault)>(
+        messageTemplate:
+            r"""The type '#type' of the getter '#name' is not a subtype of the type '#type2' of the inherited setter '#name2'.""",
+        withArguments:
+            _withArgumentsInvalidGetterSetterTypeSetterInheritedGetter);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Code<
+        Message Function(DartType _type, String name, DartType _type2,
+            String name2, bool isNonNullableByDefault)>
+    codeInvalidGetterSetterTypeSetterInheritedGetter = const Code<
+        Message Function(DartType _type, String name, DartType _type2,
+            String name2, bool isNonNullableByDefault)>(
+  "InvalidGetterSetterTypeSetterInheritedGetter",
+  templateInvalidGetterSetterTypeSetterInheritedGetter,
+);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+Message _withArgumentsInvalidGetterSetterTypeSetterInheritedGetter(
+    DartType _type,
+    String name,
+    DartType _type2,
+    String name2,
+    bool isNonNullableByDefault) {
+  TypeLabeler labeler = new TypeLabeler(isNonNullableByDefault);
+  List<Object> typeParts = labeler.labelType(_type);
+  if (name.isEmpty) throw 'No name provided';
+  name = demangleMixinApplicationName(name);
+  List<Object> type2Parts = labeler.labelType(_type2);
+  if (name2.isEmpty) throw 'No name provided';
+  name2 = demangleMixinApplicationName(name2);
+  String type = typeParts.join();
+  String type2 = type2Parts.join();
+  return new Message(codeInvalidGetterSetterTypeSetterInheritedGetter,
+      message:
+          """The type '${type}' of the getter '${name}' is not a subtype of the type '${type2}' of the inherited setter '${name2}'.""" +
+              labeler.originMessages,
+      arguments: {
+        'type': _type,
+        'name': name,
+        'type2': _type2,
+        'name2': name2
+      });
+}
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Template<
+        Message Function(DartType _type, String name, DartType _type2,
+            String name2, bool isNonNullableByDefault)>
+    templateInvalidGetterSetterTypeSetterInheritedGetterLegacy = const Template<
+            Message Function(DartType _type, String name, DartType _type2,
+                String name2, bool isNonNullableByDefault)>(
+        messageTemplate:
+            r"""The type '#type' of the getter '#name' is not assignable to the type '#type2' of the inherited setter '#name2'.""",
+        withArguments:
+            _withArgumentsInvalidGetterSetterTypeSetterInheritedGetterLegacy);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Code<
+        Message Function(DartType _type, String name, DartType _type2,
+            String name2, bool isNonNullableByDefault)>
+    codeInvalidGetterSetterTypeSetterInheritedGetterLegacy = const Code<
+        Message Function(DartType _type, String name, DartType _type2,
+            String name2, bool isNonNullableByDefault)>(
+  "InvalidGetterSetterTypeSetterInheritedGetterLegacy",
+  templateInvalidGetterSetterTypeSetterInheritedGetterLegacy,
+);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+Message _withArgumentsInvalidGetterSetterTypeSetterInheritedGetterLegacy(
+    DartType _type,
+    String name,
+    DartType _type2,
+    String name2,
+    bool isNonNullableByDefault) {
+  TypeLabeler labeler = new TypeLabeler(isNonNullableByDefault);
+  List<Object> typeParts = labeler.labelType(_type);
+  if (name.isEmpty) throw 'No name provided';
+  name = demangleMixinApplicationName(name);
+  List<Object> type2Parts = labeler.labelType(_type2);
+  if (name2.isEmpty) throw 'No name provided';
+  name2 = demangleMixinApplicationName(name2);
+  String type = typeParts.join();
+  String type2 = type2Parts.join();
+  return new Message(codeInvalidGetterSetterTypeSetterInheritedGetterLegacy,
+      message:
+          """The type '${type}' of the getter '${name}' is not assignable to the type '${type2}' of the inherited setter '${name2}'.""" +
+              labeler.originMessages,
+      arguments: {
+        'type': _type,
+        'name': name,
+        'type2': _type2,
+        'name2': name2
+      });
+}
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Template<
     Message Function(
         DartType _type,
         DartType _type2,
diff --git a/pkg/front_end/lib/src/fasta/kernel/class_hierarchy_builder.dart b/pkg/front_end/lib/src/fasta/kernel/class_hierarchy_builder.dart
index 13c33ac..43778fe 100644
--- a/pkg/front_end/lib/src/fasta/kernel/class_hierarchy_builder.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/class_hierarchy_builder.dart
@@ -240,6 +240,9 @@
 
   void inferType(ClassHierarchyBuilder hierarchy);
   void registerOverrideDependency(ClassMember overriddenMember);
+
+  /// Returns `true` if this has the same underlying declaration as [other].
+  bool isSameDeclaration(ClassMember other);
 }
 
 bool hasSameSignature(FunctionNode a, FunctionNode b) {
@@ -326,9 +329,9 @@
   final List<DelayedTypeComputation> _delayedTypeComputations =
       <DelayedTypeComputation>[];
 
-  final List<DelayedOverrideCheck> _overrideChecks = <DelayedOverrideCheck>[];
+  final List<DelayedCheck> _delayedChecks = <DelayedCheck>[];
 
-  final List<ClassMember> _delayedMemberChecks = <ClassMember>[];
+  final List<ClassMember> _delayedMemberComputations = <ClassMember>[];
 
   final CoreTypes coreTypes;
 
@@ -345,9 +348,9 @@
   void clear() {
     nodes.clear();
     substitutions.clear();
-    _overrideChecks.clear();
+    _delayedChecks.clear();
     _delayedTypeComputations.clear();
-    _delayedMemberChecks.clear();
+    _delayedMemberComputations.clear();
   }
 
   void registerDelayedTypeComputation(DelayedTypeComputation computation) {
@@ -356,11 +359,17 @@
 
   void registerOverrideCheck(
       SourceClassBuilder classBuilder, ClassMember a, ClassMember b) {
-    _overrideChecks.add(new DelayedOverrideCheck(classBuilder, a, b));
+    _delayedChecks.add(new DelayedOverrideCheck(classBuilder, a, b));
   }
 
-  void registerMemberCheck(ClassMember member) {
-    _delayedMemberChecks.add(member);
+  void registerGetterSetterCheck(
+      SourceClassBuilder classBuilder, ClassMember getter, ClassMember setter) {
+    _delayedChecks
+        .add(new DelayedGetterSetterCheck(classBuilder, getter, setter));
+  }
+
+  void registerMemberComputation(ClassMember member) {
+    _delayedMemberComputations.add(member);
   }
 
   List<DelayedTypeComputation> takeDelayedTypeComputations() {
@@ -369,15 +378,15 @@
     return list;
   }
 
-  List<DelayedOverrideCheck> takeDelayedOverrideChecks() {
-    List<DelayedOverrideCheck> list = _overrideChecks.toList();
-    _overrideChecks.clear();
+  List<DelayedCheck> takeDelayedChecks() {
+    List<DelayedCheck> list = _delayedChecks.toList();
+    _delayedChecks.clear();
     return list;
   }
 
-  List<ClassMember> takeDelayedMemberChecks() {
-    List<ClassMember> list = _delayedMemberChecks.toList();
-    _delayedMemberChecks.clear();
+  List<ClassMember> takeDelayedMemberComputations() {
+    List<ClassMember> list = _delayedMemberComputations.toList();
+    _delayedMemberComputations.clear();
     return list;
   }
 
@@ -1781,7 +1790,7 @@
                     shouldModifyKernel,
                     concrete.isAbstract,
                     concrete.name);
-                hierarchy.registerMemberCheck(result);
+                hierarchy.registerMemberComputation(result);
               }
             } else if (classBuilder.isMixinApplication &&
                 declaredMember.classBuilder != classBuilder) {
@@ -1793,7 +1802,7 @@
                   shouldModifyKernel,
                   isInheritableConflict: false);
               if (result.needsComputation) {
-                hierarchy.registerMemberCheck(result);
+                hierarchy.registerMemberComputation(result);
               }
             }
 
@@ -1820,7 +1829,7 @@
           }
           if (extendedMember.isInheritableConflict) {
             extendedMember = extendedMember.withParent(classBuilder);
-            hierarchy.registerMemberCheck(extendedMember);
+            hierarchy.registerMemberComputation(extendedMember);
           }
           if (extendedMember.classBuilder.library.isNonNullableByDefault &&
               !classBuilder.library.isNonNullableByDefault) {
@@ -1834,7 +1843,7 @@
                   extendedMember.isAbstract,
                   extendedMember.name,
                   isImplicitlyAbstract: extendedMember.isAbstract);
-              hierarchy.registerMemberCheck(extendedMember);
+              hierarchy.registerMemberComputation(extendedMember);
             }
           }
           return extendedMember;
@@ -1923,7 +1932,7 @@
                       shouldModifyKernel);
                 }
                 if (result.needsComputation) {
-                  hierarchy.registerMemberCheck(result);
+                  hierarchy.registerMemberComputation(result);
                 }
               }
 
@@ -1936,7 +1945,7 @@
               }
               if (interfaceMember.isInheritableConflict) {
                 interfaceMember = interfaceMember.withParent(classBuilder);
-                hierarchy.registerMemberCheck(interfaceMember);
+                hierarchy.registerMemberComputation(interfaceMember);
               }
               if (interfaceMember.classBuilder.library.isNonNullableByDefault &&
                   !classBuilder.library.isNonNullableByDefault) {
@@ -1950,7 +1959,7 @@
                       interfaceMember.isAbstract,
                       interfaceMember.name,
                       isImplicitlyAbstract: interfaceMember.isAbstract);
-                  hierarchy.registerMemberCheck(interfaceMember);
+                  hierarchy.registerMemberComputation(interfaceMember);
                 }
               }
               return interfaceMember;
@@ -2041,6 +2050,18 @@
           classSetter = interfaceSetter;
         }
       }
+      if (classBuilder is SourceClassBuilder) {
+        ClassMember member = interfaceMember ?? classMember;
+        ClassMember setter = interfaceSetter ?? classSetter;
+        if (member != null &&
+            setter != null &&
+            member.isProperty &&
+            setter.isProperty &&
+            member.isStatic == setter.isStatic &&
+            !member.isSameDeclaration(setter)) {
+          hierarchy.registerGetterSetterCheck(classBuilder, member, setter);
+        }
+      }
       if (classMember != null) {
         classMemberMap[name] = classMember;
       }
@@ -2576,7 +2597,11 @@
   }
 }
 
-class DelayedOverrideCheck {
+abstract class DelayedCheck {
+  void check(ClassHierarchyBuilder hierarchy);
+}
+
+class DelayedOverrideCheck implements DelayedCheck {
   final SourceClassBuilder classBuilder;
   final ClassMember declaredMember;
   final ClassMember overriddenMember;
@@ -2599,6 +2624,20 @@
   }
 }
 
+class DelayedGetterSetterCheck implements DelayedCheck {
+  final SourceClassBuilder classBuilder;
+  final ClassMember getter;
+  final ClassMember setter;
+
+  const DelayedGetterSetterCheck(this.classBuilder, this.getter, this.setter);
+
+  void check(ClassHierarchyBuilder hierarchy) {
+    classBuilder.checkGetterSetter(hierarchy.types, getter.getMember(hierarchy),
+        setter.getMember(hierarchy),
+        isInterfaceCheck: !classBuilder.isMixinApplication);
+  }
+}
+
 class DelayedTypeComputation {
   final ClassHierarchyNodeBuilder builder;
   final ClassMember declaredMember;
@@ -2830,6 +2869,12 @@
             [this], isProperty, isSetter, modifyKernel, isAbstract, name);
   }
 
+  @override
+  bool isSameDeclaration(ClassMember other) {
+    // This could be more precise but it currently has no benefit.
+    return identical(this, other);
+  }
+
   static ClassMember combined(
       ClassBuilder parent,
       ClassMember concreteImplementation,
@@ -3114,6 +3159,12 @@
             isImplicitlyAbstract: isImplicitlyAbstract);
   }
 
+  @override
+  bool isSameDeclaration(ClassMember other) {
+    // This could be more precise but it currently has no benefit.
+    return identical(this, other);
+  }
+
   static ClassMember combined(ClassBuilder parent, ClassMember a, ClassMember b,
       bool isSetter, bool createForwarders) {
     assert(a.isProperty == b.isProperty,
@@ -3236,6 +3287,15 @@
 
   @override
   ClassMember get concrete => concreteImplementation;
+
+  @override
+  bool isSameDeclaration(ClassMember other) {
+    if (identical(this, other)) return false;
+    return other is AbstractMemberOverridingImplementation &&
+        classBuilder == other.classBuilder &&
+        abstract.isSameDeclaration(other.abstract) &&
+        concrete.isSameDeclaration(other.concrete);
+  }
 }
 
 void addDeclarationIfDifferent(
diff --git a/pkg/front_end/lib/src/fasta/kernel/kernel_builder.dart b/pkg/front_end/lib/src/fasta/kernel/kernel_builder.dart
index b17364e3..c0b1459 100644
--- a/pkg/front_end/lib/src/fasta/kernel/kernel_builder.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/kernel_builder.dart
@@ -15,7 +15,7 @@
 import '../combinator.dart' as fasta;
 
 export 'class_hierarchy_builder.dart'
-    show ClassHierarchyBuilder, ClassMember, DelayedOverrideCheck;
+    show ClassHierarchyBuilder, ClassMember, DelayedCheck;
 
 export 'implicit_field_type.dart' show ImplicitFieldType;
 
diff --git a/pkg/front_end/lib/src/fasta/source/source_class_builder.dart b/pkg/front_end/lib/src/fasta/source/source_class_builder.dart
index a96c1f0..c58a522 100644
--- a/pkg/front_end/lib/src/fasta/source/source_class_builder.dart
+++ b/pkg/front_end/lib/src/fasta/source/source_class_builder.dart
@@ -1204,6 +1204,155 @@
     // TODO(ahe): Handle other cases: accessors, operators, and fields.
   }
 
+  void checkGetterSetter(Types types, Member getter, Member setter,
+      {bool isInterfaceCheck = false}) {
+    if (getter == setter) {
+      return;
+    }
+    if (cls != getter.enclosingClass &&
+        getter.enclosingClass == setter.enclosingClass) {
+      return;
+    }
+
+    DartType getterType = getter.getterType;
+    if (getter.enclosingClass.typeParameters.isNotEmpty) {
+      getterType = Substitution.fromPairs(
+              getter.enclosingClass.typeParameters,
+              types.hierarchy.getTypeArgumentsAsInstanceOf(
+                  thisType, getter.enclosingClass))
+          .substituteType(getterType);
+    }
+
+    DartType setterType = setter.setterType;
+    if (setter.enclosingClass.typeParameters.isNotEmpty) {
+      setterType = Substitution.fromPairs(
+              setter.enclosingClass.typeParameters,
+              types.hierarchy.getTypeArgumentsAsInstanceOf(
+                  thisType, setter.enclosingClass))
+          .substituteType(setterType);
+    }
+
+    if (getterType is InvalidType || setterType is InvalidType) {
+      // Don't report a problem as something else is wrong that has already
+      // been reported.
+    } else {
+      bool isValid = types.isSubtypeOf(
+          getterType,
+          setterType,
+          library.isNonNullableByDefault
+              ? SubtypeCheckMode.withNullabilities
+              : SubtypeCheckMode.ignoringNullabilities);
+      if (!isValid && !library.isNonNullableByDefault) {
+        // Allow assignability in legacy libraries.
+        isValid = types.isSubtypeOf(
+            setterType, getterType, SubtypeCheckMode.ignoringNullabilities);
+      }
+      if (!isValid) {
+        Member getterOrigin = getter.memberSignatureOrigin ?? getter;
+        Member setterOrigin = setter.memberSignatureOrigin ?? setter;
+        String getterMemberName = '${getterOrigin.enclosingClass.name}'
+            '.${getterOrigin.name.text}';
+        String setterMemberName = '${setterOrigin.enclosingClass.name}'
+            '.${setterOrigin.name.text}';
+        if (getterOrigin.enclosingClass == cls &&
+            setterOrigin.enclosingClass == cls) {
+          Template<Message Function(DartType, String, DartType, String, bool)>
+              template = library.isNonNullableByDefault
+                  ? templateInvalidGetterSetterType
+                  : templateInvalidGetterSetterTypeLegacy;
+          library.addProblem(
+              template.withArguments(getterType, getterMemberName, setterType,
+                  setterMemberName, library.isNonNullableByDefault),
+              getterOrigin.fileOffset,
+              getterOrigin.name.text.length,
+              getterOrigin.fileUri,
+              context: [
+                templateInvalidGetterSetterTypeSetterContext
+                    .withArguments(setterMemberName)
+                    .withLocation(setterOrigin.fileUri, setterOrigin.fileOffset,
+                        setterOrigin.name.text.length)
+              ]);
+        } else if (getterOrigin.enclosingClass == cls) {
+          Template<Message Function(DartType, String, DartType, String, bool)>
+              template = library.isNonNullableByDefault
+                  ? templateInvalidGetterSetterTypeSetterInheritedGetter
+                  : templateInvalidGetterSetterTypeSetterInheritedGetterLegacy;
+          if (getterOrigin is Field) {
+            template = library.isNonNullableByDefault
+                ? templateInvalidGetterSetterTypeSetterInheritedField
+                : templateInvalidGetterSetterTypeSetterInheritedFieldLegacy;
+          }
+          library.addProblem(
+              template.withArguments(getterType, getterMemberName, setterType,
+                  setterMemberName, library.isNonNullableByDefault),
+              getterOrigin.fileOffset,
+              getterOrigin.name.text.length,
+              getterOrigin.fileUri,
+              context: [
+                templateInvalidGetterSetterTypeSetterContext
+                    .withArguments(setterMemberName)
+                    .withLocation(setterOrigin.fileUri, setterOrigin.fileOffset,
+                        setterOrigin.name.text.length)
+              ]);
+        } else if (setterOrigin.enclosingClass == cls) {
+          Template<Message Function(DartType, String, DartType, String, bool)>
+              template = library.isNonNullableByDefault
+                  ? templateInvalidGetterSetterTypeGetterInherited
+                  : templateInvalidGetterSetterTypeGetterInheritedLegacy;
+          Template<Message Function(String)> context =
+              templateInvalidGetterSetterTypeGetterContext;
+          if (getterOrigin is Field) {
+            template = library.isNonNullableByDefault
+                ? templateInvalidGetterSetterTypeFieldInherited
+                : templateInvalidGetterSetterTypeFieldInheritedLegacy;
+            context = templateInvalidGetterSetterTypeFieldContext;
+          }
+          library.addProblem(
+              template.withArguments(getterType, getterMemberName, setterType,
+                  setterMemberName, library.isNonNullableByDefault),
+              setterOrigin.fileOffset,
+              setterOrigin.name.text.length,
+              setterOrigin.fileUri,
+              context: [
+                context.withArguments(getterMemberName).withLocation(
+                    getterOrigin.fileUri,
+                    getterOrigin.fileOffset,
+                    getterOrigin.name.text.length)
+              ]);
+        } else {
+          Template<Message Function(DartType, String, DartType, String, bool)>
+              template = library.isNonNullableByDefault
+                  ? templateInvalidGetterSetterTypeBothInheritedGetter
+                  : templateInvalidGetterSetterTypeBothInheritedGetterLegacy;
+          Template<Message Function(String)> context =
+              templateInvalidGetterSetterTypeGetterContext;
+          if (getterOrigin is Field) {
+            template = library.isNonNullableByDefault
+                ? templateInvalidGetterSetterTypeBothInheritedField
+                : templateInvalidGetterSetterTypeBothInheritedFieldLegacy;
+            context = templateInvalidGetterSetterTypeFieldContext;
+          }
+          library.addProblem(
+              template.withArguments(getterType, getterMemberName, setterType,
+                  setterMemberName, library.isNonNullableByDefault),
+              charOffset,
+              noLength,
+              fileUri,
+              context: [
+                context.withArguments(getterMemberName).withLocation(
+                    getterOrigin.fileUri,
+                    getterOrigin.fileOffset,
+                    getterOrigin.name.text.length),
+                templateInvalidGetterSetterTypeSetterContext
+                    .withArguments(setterMemberName)
+                    .withLocation(setterOrigin.fileUri, setterOrigin.fileOffset,
+                        setterOrigin.name.text.length)
+              ]);
+        }
+      }
+    }
+  }
+
   Uri _getMemberUri(Member member) {
     if (member is Field) return member.fileUri;
     if (member is Procedure) return member.fileUri;
diff --git a/pkg/front_end/lib/src/fasta/source/source_loader.dart b/pkg/front_end/lib/src/fasta/source/source_loader.dart
index 23761f4..14803dd 100644
--- a/pkg/front_end/lib/src/fasta/source/source_loader.dart
+++ b/pkg/front_end/lib/src/fasta/source/source_loader.dart
@@ -88,7 +88,7 @@
 import '../fasta_codes.dart';
 
 import '../kernel/kernel_builder.dart'
-    show ClassHierarchyBuilder, ClassMember, DelayedOverrideCheck;
+    show ClassHierarchyBuilder, ClassMember, DelayedCheck;
 
 import '../kernel/kernel_target.dart' show KernelTarget;
 
@@ -1026,8 +1026,7 @@
   }
 
   void checkOverrides(List<SourceClassBuilder> sourceClasses) {
-    List<DelayedOverrideCheck> overrideChecks =
-        builderHierarchy.takeDelayedOverrideChecks();
+    List<DelayedCheck> overrideChecks = builderHierarchy.takeDelayedChecks();
     for (int i = 0; i < overrideChecks.length; i++) {
       overrideChecks[i].check(builderHierarchy);
     }
@@ -1039,7 +1038,7 @@
 
   void checkAbstractMembers(List<SourceClassBuilder> sourceClasses) {
     List<ClassMember> delayedMemberChecks =
-        builderHierarchy.takeDelayedMemberChecks();
+        builderHierarchy.takeDelayedMemberComputations();
     Set<Class> changedClasses = new Set<Class>();
     for (int i = 0; i < delayedMemberChecks.length; i++) {
       delayedMemberChecks[i].getMember(builderHierarchy);
diff --git a/pkg/front_end/messages.status b/pkg/front_end/messages.status
index c083e2c..5679493 100644
--- a/pkg/front_end/messages.status
+++ b/pkg/front_end/messages.status
@@ -416,6 +416,20 @@
 InvalidCatchArguments/example: Fail
 InvalidContinueTarget/analyzerCode: Fail
 InvalidContinueTarget/example: Fail
+InvalidGetterSetterType/analyzerCode: Fail
+InvalidGetterSetterTypeBothInheritedField/analyzerCode: Fail
+InvalidGetterSetterTypeBothInheritedFieldLegacy/analyzerCode: Fail
+InvalidGetterSetterTypeBothInheritedGetter/analyzerCode: Fail
+InvalidGetterSetterTypeBothInheritedGetterLegacy/analyzerCode: Fail
+InvalidGetterSetterTypeFieldInherited/analyzerCode: Fail
+InvalidGetterSetterTypeFieldInheritedLegacy/analyzerCode: Fail
+InvalidGetterSetterTypeGetterInherited/analyzerCode: Fail
+InvalidGetterSetterTypeGetterInheritedLegacy/analyzerCode: Fail
+InvalidGetterSetterTypeLegacy/analyzerCode: Fail
+InvalidGetterSetterTypeSetterInheritedField/analyzerCode: Fail
+InvalidGetterSetterTypeSetterInheritedFieldLegacy/analyzerCode: Fail
+InvalidGetterSetterTypeSetterInheritedGetter/analyzerCode: Fail
+InvalidGetterSetterTypeSetterInheritedGetterLegacy/analyzerCode: Fail
 InvalidInitializer/example: Fail
 InvalidPackageUri/analyzerCode: Fail
 InvalidPackageUri/example: Fail
diff --git a/pkg/front_end/messages.yaml b/pkg/front_end/messages.yaml
index d182347..7412866 100644
--- a/pkg/front_end/messages.yaml
+++ b/pkg/front_end/messages.yaml
@@ -2236,6 +2236,171 @@
       method({required int? a});
     }
 
+InvalidGetterSetterType:
+  template: "The type '#type' of the getter '#name' is not a subtype of the type '#type2' of the setter '#name2'."
+  configuration: nnbd-strong
+  script: |
+    abstract class A {
+      num get property;
+      void set property(int i);
+    }
+
+InvalidGetterSetterTypeGetterInherited:
+  template: "The type '#type' of the inherited getter '#name' is not a subtype of the type '#type2' of the setter '#name2'."
+  configuration: nnbd-strong
+  script: |
+    abstract class A {
+      num get property;
+    }
+    abstract class B implements A {
+      void set property(int i);
+    }
+
+InvalidGetterSetterTypeFieldInherited:
+  template: "The type '#type' of the inherited field '#name' is not a subtype of the type '#type2' of the setter '#name2'."
+  configuration: nnbd-strong
+  script: |
+    abstract class A {
+      final num property;
+      A(this.property);
+    }
+    abstract class B implements A {
+      void set property(int i);
+    }
+
+InvalidGetterSetterTypeSetterInheritedGetter:
+  template: "The type '#type' of the getter '#name' is not a subtype of the type '#type2' of the inherited setter '#name2'."
+  configuration: nnbd-strong
+  script: |
+    abstract class A {
+      void set property(int i);
+    }
+    abstract class B implements A {
+      num get property;
+    }
+
+InvalidGetterSetterTypeSetterInheritedField:
+  template: "The type '#type' of the field '#name' is not a subtype of the type '#type2' of the inherited setter '#name2'."
+  configuration: nnbd-strong
+  script: |
+    abstract class A {
+      void set property(int i);
+    }
+    abstract class B implements A {
+      final num property;
+      B(this.property);
+    }
+
+InvalidGetterSetterTypeBothInheritedField:
+  template: "The type '#type' of the inherited field '#name' is not a subtype of the type '#type2' of the inherited setter '#name2'."
+  configuration: nnbd-strong
+  script: |
+    abstract class A {
+      final num property;
+      A(this.property);
+    }
+    abstract class B {
+      void set property(int i);
+    }
+    abstract class C implements A, B {}
+
+InvalidGetterSetterTypeBothInheritedGetter:
+  template: "The type '#type' of the inherited getter '#name' is not a subtype of the type '#type2' of the inherited setter '#name2'."
+  configuration: nnbd-strong
+  script: |
+    abstract class A {
+      num get property;
+    }
+    abstract class B {
+      void set property(int i);
+    }
+    abstract class C implements A, B {}
+
+InvalidGetterSetterTypeLegacy:
+  template: "The type '#type' of the getter '#name' is not assignable to the type '#type2' of the setter '#name2'."
+  script: |
+    abstract class A {
+      String get property;
+      void set property(int i);
+    }
+
+InvalidGetterSetterTypeGetterInheritedLegacy:
+  template: "The type '#type' of the inherited getter '#name' is not assignable to the type '#type2' of the setter '#name2'."
+  script: |
+    abstract class A {
+      String get property;
+    }
+    abstract class B implements A {
+      void set property(int i);
+    }
+
+InvalidGetterSetterTypeFieldInheritedLegacy:
+  template: "The type '#type' of the inherited field '#name' is not assignable to the type '#type2' of the setter '#name2'."
+  script: |
+    abstract class A {
+      final String property;
+      A(this.property);
+    }
+    abstract class B implements A {
+      void set property(int i);
+    }
+
+InvalidGetterSetterTypeSetterInheritedGetterLegacy:
+  template: "The type '#type' of the getter '#name' is not assignable to the type '#type2' of the inherited setter '#name2'."
+  script: |
+    abstract class A {
+      void set property(int i);
+    }
+    abstract class B implements A {
+      String get property;
+    }
+
+InvalidGetterSetterTypeSetterInheritedFieldLegacy:
+  template: "The type '#type' of the field '#name' is not assignable to the type '#type2' of the inherited setter '#name2'."
+  script: |
+    abstract class A {
+      void set property(int i);
+    }
+    abstract class B implements A {
+      final String property;
+      B(this.property);
+    }
+
+InvalidGetterSetterTypeBothInheritedFieldLegacy:
+  template: "The type '#type' of the inherited field '#name' is not assignable to the type '#type2' of the inherited setter '#name2'."
+  script: |
+    abstract class A {
+      final String property;
+      A(this.property);
+    }
+    abstract class B {
+      void set property(int i);
+    }
+    abstract class C implements A, B {}
+
+InvalidGetterSetterTypeBothInheritedGetterLegacy:
+  template: "The type '#type' of the inherited getter '#name' is not assignable to the type '#type2' of the inherited setter '#name2'."
+  script: |
+    abstract class A {
+      String get property;
+    }
+    abstract class B {
+      void set property(int i);
+    }
+    abstract class C implements A, B {}
+
+InvalidGetterSetterTypeFieldContext:
+  template: "This is the declaration of the field '#name'."
+  severity: CONTEXT
+
+InvalidGetterSetterTypeGetterContext:
+  template: "This is the declaration of the getter '#name'."
+  severity: CONTEXT
+
+InvalidGetterSetterTypeSetterContext:
+  template: "This is the declaration of the setter '#name'."
+  severity: CONTEXT
+
 PartOfSelf:
   template: "A file can't be a part of itself."
   analyzerCode: PART_OF_NON_PART
diff --git a/pkg/front_end/test/fasta/bootstrap_test.dart b/pkg/front_end/test/fasta/bootstrap_test.dart
index 39effb5..37dff17 100644
--- a/pkg/front_end/test/fasta/bootstrap_test.dart
+++ b/pkg/front_end/test/fasta/bootstrap_test.dart
@@ -59,7 +59,7 @@
       ],
       suppressOutput: false);
   if (result.exitCode != 0) {
-    throw "Compilation failed.";
+    throw "Compilation failed:\n${result.output}";
   }
 }
 
diff --git a/pkg/front_end/testcases/expression/main.dart b/pkg/front_end/testcases/expression/main.dart
index e38cbea..91ad8d9 100644
--- a/pkg/front_end/testcases/expression/main.dart
+++ b/pkg/front_end/testcases/expression/main.dart
@@ -42,7 +42,7 @@
     return "";
   }
 
-  void set z(int _) {}
+  void set z(_) {}
   void _privMethod() {}
 }
 
diff --git a/pkg/front_end/testcases/general/getter_vs_setter_type.dart b/pkg/front_end/testcases/general/getter_vs_setter_type.dart
new file mode 100644
index 0000000..2f92b93
--- /dev/null
+++ b/pkg/front_end/testcases/general/getter_vs_setter_type.dart
@@ -0,0 +1,105 @@
+// 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.
+
+abstract class A {
+  int get property1; // ok
+  void set property1(int i);
+
+  int get property2; // ok
+  void set property2(int i);
+
+  String get property3; // error
+  void set property3(int i);
+
+  int property4; // ok
+
+  int property5; // ok
+
+  covariant String property6; // ok
+}
+
+abstract class B1 {
+  int get property1;
+
+  int get property2;
+
+  String get property3;
+
+  final int property4;
+
+  final int property5;
+
+  final String property6;
+
+  B1(this.property4, this.property5, this.property6);
+}
+
+abstract class B2 implements B1 {
+  void set property1(int i); // ok
+
+  void set property2(String i); // error
+
+  void set property3(int i); // error
+
+  void set property4(int i); // ok
+
+  void set property5(String i); // error
+
+  void set property6(int i); // error
+}
+
+abstract class C1 {
+  void set property1(int i);
+
+  void set property2(String i);
+
+  void set property3(int i);
+
+  int property4;
+
+  String property5;
+
+  int property6;
+}
+
+abstract class C2 implements C1 {
+  int get property1; // ok
+
+  int get property2; // error
+
+  String get property3; // error
+
+  int get property4; // ok
+
+  // This results in two errors; one for the getter/setter type mismatch and one
+  // for the getter override.
+  int get property5; // error
+
+  // This results in two errors; one for the getter/setter type mismatch and one
+  // for the getter override.
+  String get property6; // error
+}
+
+abstract class D1 {
+  int get property1;
+
+  int get property2;
+
+  String get property3;
+}
+
+abstract class D2 {
+  void set property1(int i);
+
+  void set property2(String i);
+
+  void set property3(int i);
+}
+
+abstract class D3 implements D1, D2 /* error on property2 and property3 */ {}
+
+abstract class D4
+    implements D3 /* no need for error on property2 and property3 */ {}
+
+main() {}
diff --git a/pkg/front_end/testcases/general/getter_vs_setter_type.dart.outline.expect b/pkg/front_end/testcases/general/getter_vs_setter_type.dart.outline.expect
new file mode 100644
index 0000000..d0db1ea
--- /dev/null
+++ b/pkg/front_end/testcases/general/getter_vs_setter_type.dart.outline.expect
@@ -0,0 +1,293 @@
+library;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:12:14: Error: The type 'String' of the getter 'A.property3' is not assignable to the type 'int' of the setter 'A.property3'.
+//   String get property3; // error
+//              ^^^^^^^^^
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:13:12: Context: This is the declaration of the setter 'A.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:41:12: Error: The type 'int' of the inherited getter 'B1.property2' is not assignable to the type 'String' of the setter 'B2.property2'.
+//   void set property2(String i); // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:25:11: Context: This is the declaration of the getter 'B1.property2'.
+//   int get property2;
+//           ^^^^^^^^^
+//
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:43:12: Error: The type 'String' of the inherited getter 'B1.property3' is not assignable to the type 'int' of the setter 'B2.property3'.
+//   void set property3(int i); // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:27:14: Context: This is the declaration of the getter 'B1.property3'.
+//   String get property3;
+//              ^^^^^^^^^
+//
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:47:12: Error: The type 'int' of the inherited field 'B1.property5' is not assignable to the type 'String' of the setter 'B2.property5'.
+//   void set property5(String i); // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:31:13: Context: This is the declaration of the field 'B1.property5'.
+//   final int property5;
+//             ^^^^^^^^^
+//
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:49:12: Error: The type 'String' of the inherited field 'B1.property6' is not assignable to the type 'int' of the setter 'B2.property6'.
+//   void set property6(int i); // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:33:16: Context: This is the declaration of the field 'B1.property6'.
+//   final String property6;
+//                ^^^^^^^^^
+//
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:69:11: Error: The type 'int' of the getter 'C2.property2' is not assignable to the type 'String' of the inherited setter 'C1.property2'.
+//   int get property2; // error
+//           ^^^^^^^^^
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:55:12: Context: This is the declaration of the setter 'C1.property2'.
+//   void set property2(String i);
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:71:14: Error: The type 'String' of the getter 'C2.property3' is not assignable to the type 'int' of the inherited setter 'C1.property3'.
+//   String get property3; // error
+//              ^^^^^^^^^
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:57:12: Context: This is the declaration of the setter 'C1.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:77:11: Error: The return type of the method 'C2.property5' is 'int', which does not match the return type, 'String', of the overridden method, 'C1.property5'.
+// Change to a subtype of 'String'.
+//   int get property5; // error
+//           ^
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:61:10: Context: This is the overridden method ('property5').
+//   String property5;
+//          ^
+//
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:77:11: Error: The type 'int' of the getter 'C2.property5' is not assignable to the type 'String' of the inherited setter 'C1.property5'.
+//   int get property5; // error
+//           ^^^^^^^^^
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:61:10: Context: This is the declaration of the setter 'C1.property5'.
+//   String property5;
+//          ^^^^^^^^^
+//
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:81:14: Error: The return type of the method 'C2.property6' is 'String', which does not match the return type, 'int', of the overridden method, 'C1.property6'.
+// Change to a subtype of 'int'.
+//   String get property6; // error
+//              ^
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:63:7: Context: This is the overridden method ('property6').
+//   int property6;
+//       ^
+//
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:81:14: Error: The type 'String' of the getter 'C2.property6' is not assignable to the type 'int' of the inherited setter 'C1.property6'.
+//   String get property6; // error
+//              ^^^^^^^^^
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:63:7: Context: This is the declaration of the setter 'C1.property6'.
+//   int property6;
+//       ^^^^^^^^^
+//
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:100:16: Error: The type 'int' of the inherited getter 'D1.property2' is not assignable to the type 'String' of the inherited setter 'D2.property2'.
+// abstract class D3 implements D1, D2 /* error on property2 and property3 */ {}
+//                ^
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:87:11: Context: This is the declaration of the getter 'D1.property2'.
+//   int get property2;
+//           ^^^^^^^^^
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:95:12: Context: This is the declaration of the setter 'D2.property2'.
+//   void set property2(String i);
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:100:16: Error: The type 'String' of the inherited getter 'D1.property3' is not assignable to the type 'int' of the inherited setter 'D2.property3'.
+// abstract class D3 implements D1, D2 /* error on property2 and property3 */ {}
+//                ^
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:89:14: Context: This is the declaration of the getter 'D1.property3'.
+//   String get property3;
+//              ^^^^^^^^^
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:97:12: Context: This is the declaration of the setter 'D2.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:102:16: Error: The type 'int' of the inherited getter 'D1.property2' is not assignable to the type 'String' of the inherited setter 'D2.property2'.
+// abstract class D4
+//                ^
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:87:11: Context: This is the declaration of the getter 'D1.property2'.
+//   int get property2;
+//           ^^^^^^^^^
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:95:12: Context: This is the declaration of the setter 'D2.property2'.
+//   void set property2(String i);
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:102:16: Error: The type 'String' of the inherited getter 'D1.property3' is not assignable to the type 'int' of the inherited setter 'D2.property3'.
+// abstract class D4
+//                ^
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:89:14: Context: This is the declaration of the getter 'D1.property3'.
+//   String get property3;
+//              ^^^^^^^^^
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:97:12: Context: This is the declaration of the setter 'D2.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+import self as self;
+import "dart:core" as core;
+
+abstract class A extends core::Object {
+  field core::int* property4;
+  field core::int* property5;
+  covariant field core::String* property6;
+  synthetic constructor •() → self::A*
+    ;
+  abstract get property1() → core::int*;
+  abstract set property1(core::int* i) → void;
+  abstract get property2() → core::int*;
+  abstract set property2(core::int* i) → void;
+  abstract get property3() → core::String*;
+  abstract set property3(core::int* i) → void;
+  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
+}
+abstract class B1 extends core::Object {
+  final field core::int* property4;
+  final field core::int* property5;
+  final field core::String* property6;
+  constructor •(core::int* property4, core::int* property5, core::String* property6) → self::B1*
+    ;
+  abstract get property1() → core::int*;
+  abstract get property2() → core::int*;
+  abstract get property3() → core::String*;
+  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
+}
+abstract class B2 extends core::Object implements self::B1 {
+  synthetic constructor •() → self::B2*
+    ;
+  abstract set property1(core::int* i) → void;
+  abstract set property2(core::String* i) → void;
+  abstract set property3(core::int* i) → void;
+  abstract set property4(core::int* i) → void;
+  abstract set property5(core::String* i) → void;
+  abstract set property6(core::int* i) → void;
+  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
+}
+abstract class C1 extends core::Object {
+  field core::int* property4;
+  field core::String* property5;
+  field core::int* property6;
+  synthetic constructor •() → self::C1*
+    ;
+  abstract set property1(core::int* i) → void;
+  abstract set property2(core::String* i) → void;
+  abstract set property3(core::int* i) → void;
+  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
+}
+abstract class C2 extends core::Object implements self::C1 {
+  synthetic constructor •() → self::C2*
+    ;
+  abstract get property1() → core::int*;
+  abstract get property2() → core::int*;
+  abstract get property3() → core::String*;
+  abstract get property4() → core::int*;
+  abstract get property5() → core::int*;
+  abstract get property6() → core::String*;
+  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
+}
+abstract class D1 extends core::Object {
+  synthetic constructor •() → self::D1*
+    ;
+  abstract get property1() → core::int*;
+  abstract get property2() → core::int*;
+  abstract get property3() → core::String*;
+  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
+}
+abstract class D2 extends core::Object {
+  synthetic constructor •() → self::D2*
+    ;
+  abstract set property1(core::int* i) → void;
+  abstract set property2(core::String* i) → void;
+  abstract set property3(core::int* i) → void;
+  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
+}
+abstract class D3 extends core::Object implements self::D1, self::D2 {
+  synthetic constructor •() → self::D3*
+    ;
+  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
+}
+abstract class D4 extends core::Object implements self::D3 {
+  synthetic constructor •() → self::D4*
+    ;
+  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
+  ;
diff --git a/pkg/front_end/testcases/general/getter_vs_setter_type.dart.strong.expect b/pkg/front_end/testcases/general/getter_vs_setter_type.dart.strong.expect
new file mode 100644
index 0000000..eb497ad
--- /dev/null
+++ b/pkg/front_end/testcases/general/getter_vs_setter_type.dart.strong.expect
@@ -0,0 +1,301 @@
+library;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:12:14: Error: The type 'String' of the getter 'A.property3' is not assignable to the type 'int' of the setter 'A.property3'.
+//   String get property3; // error
+//              ^^^^^^^^^
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:13:12: Context: This is the declaration of the setter 'A.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:41:12: Error: The type 'int' of the inherited getter 'B1.property2' is not assignable to the type 'String' of the setter 'B2.property2'.
+//   void set property2(String i); // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:25:11: Context: This is the declaration of the getter 'B1.property2'.
+//   int get property2;
+//           ^^^^^^^^^
+//
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:43:12: Error: The type 'String' of the inherited getter 'B1.property3' is not assignable to the type 'int' of the setter 'B2.property3'.
+//   void set property3(int i); // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:27:14: Context: This is the declaration of the getter 'B1.property3'.
+//   String get property3;
+//              ^^^^^^^^^
+//
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:47:12: Error: The type 'int' of the inherited field 'B1.property5' is not assignable to the type 'String' of the setter 'B2.property5'.
+//   void set property5(String i); // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:31:13: Context: This is the declaration of the field 'B1.property5'.
+//   final int property5;
+//             ^^^^^^^^^
+//
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:49:12: Error: The type 'String' of the inherited field 'B1.property6' is not assignable to the type 'int' of the setter 'B2.property6'.
+//   void set property6(int i); // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:33:16: Context: This is the declaration of the field 'B1.property6'.
+//   final String property6;
+//                ^^^^^^^^^
+//
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:69:11: Error: The type 'int' of the getter 'C2.property2' is not assignable to the type 'String' of the inherited setter 'C1.property2'.
+//   int get property2; // error
+//           ^^^^^^^^^
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:55:12: Context: This is the declaration of the setter 'C1.property2'.
+//   void set property2(String i);
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:71:14: Error: The type 'String' of the getter 'C2.property3' is not assignable to the type 'int' of the inherited setter 'C1.property3'.
+//   String get property3; // error
+//              ^^^^^^^^^
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:57:12: Context: This is the declaration of the setter 'C1.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:77:11: Error: The return type of the method 'C2.property5' is 'int', which does not match the return type, 'String', of the overridden method, 'C1.property5'.
+// Change to a subtype of 'String'.
+//   int get property5; // error
+//           ^
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:61:10: Context: This is the overridden method ('property5').
+//   String property5;
+//          ^
+//
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:77:11: Error: The type 'int' of the getter 'C2.property5' is not assignable to the type 'String' of the inherited setter 'C1.property5'.
+//   int get property5; // error
+//           ^^^^^^^^^
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:61:10: Context: This is the declaration of the setter 'C1.property5'.
+//   String property5;
+//          ^^^^^^^^^
+//
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:81:14: Error: The return type of the method 'C2.property6' is 'String', which does not match the return type, 'int', of the overridden method, 'C1.property6'.
+// Change to a subtype of 'int'.
+//   String get property6; // error
+//              ^
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:63:7: Context: This is the overridden method ('property6').
+//   int property6;
+//       ^
+//
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:81:14: Error: The type 'String' of the getter 'C2.property6' is not assignable to the type 'int' of the inherited setter 'C1.property6'.
+//   String get property6; // error
+//              ^^^^^^^^^
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:63:7: Context: This is the declaration of the setter 'C1.property6'.
+//   int property6;
+//       ^^^^^^^^^
+//
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:100:16: Error: The type 'int' of the inherited getter 'D1.property2' is not assignable to the type 'String' of the inherited setter 'D2.property2'.
+// abstract class D3 implements D1, D2 /* error on property2 and property3 */ {}
+//                ^
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:87:11: Context: This is the declaration of the getter 'D1.property2'.
+//   int get property2;
+//           ^^^^^^^^^
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:95:12: Context: This is the declaration of the setter 'D2.property2'.
+//   void set property2(String i);
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:100:16: Error: The type 'String' of the inherited getter 'D1.property3' is not assignable to the type 'int' of the inherited setter 'D2.property3'.
+// abstract class D3 implements D1, D2 /* error on property2 and property3 */ {}
+//                ^
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:89:14: Context: This is the declaration of the getter 'D1.property3'.
+//   String get property3;
+//              ^^^^^^^^^
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:97:12: Context: This is the declaration of the setter 'D2.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:102:16: Error: The type 'int' of the inherited getter 'D1.property2' is not assignable to the type 'String' of the inherited setter 'D2.property2'.
+// abstract class D4
+//                ^
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:87:11: Context: This is the declaration of the getter 'D1.property2'.
+//   int get property2;
+//           ^^^^^^^^^
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:95:12: Context: This is the declaration of the setter 'D2.property2'.
+//   void set property2(String i);
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:102:16: Error: The type 'String' of the inherited getter 'D1.property3' is not assignable to the type 'int' of the inherited setter 'D2.property3'.
+// abstract class D4
+//                ^
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:89:14: Context: This is the declaration of the getter 'D1.property3'.
+//   String get property3;
+//              ^^^^^^^^^
+// pkg/front_end/testcases/general/getter_vs_setter_type.dart:97:12: Context: This is the declaration of the setter 'D2.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+import self as self;
+import "dart:core" as core;
+
+abstract class A extends core::Object {
+  field core::int* property4 = null;
+  field core::int* property5 = null;
+  covariant field core::String* property6 = null;
+  synthetic constructor •() → self::A*
+    : super core::Object::•()
+    ;
+  abstract get property1() → core::int*;
+  abstract set property1(core::int* i) → void;
+  abstract get property2() → core::int*;
+  abstract set property2(core::int* i) → void;
+  abstract get property3() → core::String*;
+  abstract set property3(core::int* i) → void;
+  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
+}
+abstract class B1 extends core::Object {
+  final field core::int* property4;
+  final field core::int* property5;
+  final field core::String* property6;
+  constructor •(core::int* property4, core::int* property5, core::String* property6) → self::B1*
+    : self::B1::property4 = property4, self::B1::property5 = property5, self::B1::property6 = property6, super core::Object::•()
+    ;
+  abstract get property1() → core::int*;
+  abstract get property2() → core::int*;
+  abstract get property3() → core::String*;
+  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
+}
+abstract class B2 extends core::Object implements self::B1 {
+  synthetic constructor •() → self::B2*
+    : super core::Object::•()
+    ;
+  abstract set property1(core::int* i) → void;
+  abstract set property2(core::String* i) → void;
+  abstract set property3(core::int* i) → void;
+  abstract set property4(core::int* i) → void;
+  abstract set property5(core::String* i) → void;
+  abstract set property6(core::int* i) → void;
+  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
+}
+abstract class C1 extends core::Object {
+  field core::int* property4 = null;
+  field core::String* property5 = null;
+  field core::int* property6 = null;
+  synthetic constructor •() → self::C1*
+    : super core::Object::•()
+    ;
+  abstract set property1(core::int* i) → void;
+  abstract set property2(core::String* i) → void;
+  abstract set property3(core::int* i) → void;
+  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
+}
+abstract class C2 extends core::Object implements self::C1 {
+  synthetic constructor •() → self::C2*
+    : super core::Object::•()
+    ;
+  abstract get property1() → core::int*;
+  abstract get property2() → core::int*;
+  abstract get property3() → core::String*;
+  abstract get property4() → core::int*;
+  abstract get property5() → core::int*;
+  abstract get property6() → core::String*;
+  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
+}
+abstract class D1 extends core::Object {
+  synthetic constructor •() → self::D1*
+    : super core::Object::•()
+    ;
+  abstract get property1() → core::int*;
+  abstract get property2() → core::int*;
+  abstract get property3() → core::String*;
+  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
+}
+abstract class D2 extends core::Object {
+  synthetic constructor •() → self::D2*
+    : super core::Object::•()
+    ;
+  abstract set property1(core::int* i) → void;
+  abstract set property2(core::String* i) → void;
+  abstract set property3(core::int* i) → void;
+  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
+}
+abstract class D3 extends core::Object implements self::D1, self::D2 {
+  synthetic constructor •() → self::D3*
+    : 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
+}
+abstract class D4 extends core::Object implements self::D3 {
+  synthetic constructor •() → self::D4*
+    : 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 {}
diff --git a/pkg/front_end/testcases/general/getter_vs_setter_type.dart.textual_outline.expect b/pkg/front_end/testcases/general/getter_vs_setter_type.dart.textual_outline.expect
new file mode 100644
index 0000000..2018462
--- /dev/null
+++ b/pkg/front_end/testcases/general/getter_vs_setter_type.dart.textual_outline.expect
@@ -0,0 +1,66 @@
+abstract class A {
+  int get property1;
+  void set property1(int i);
+  int get property2;
+  void set property2(int i);
+  String get property3;
+  void set property3(int i);
+  int property4;
+  int property5;
+  covariant String property6;
+}
+
+abstract class B1 {
+  int get property1;
+  int get property2;
+  String get property3;
+  final int property4;
+  final int property5;
+  final String property6;
+  B1(this.property4, this.property5, this.property6);
+}
+
+abstract class B2 implements B1 {
+  void set property1(int i);
+  void set property2(String i);
+  void set property3(int i);
+  void set property4(int i);
+  void set property5(String i);
+  void set property6(int i);
+}
+
+abstract class C1 {
+  void set property1(int i);
+  void set property2(String i);
+  void set property3(int i);
+  int property4;
+  String property5;
+  int property6;
+}
+
+abstract class C2 implements C1 {
+  int get property1;
+  int get property2;
+  String get property3;
+  int get property4;
+  int get property5;
+  String get property6;
+}
+
+abstract class D1 {
+  int get property1;
+  int get property2;
+  String get property3;
+}
+
+abstract class D2 {
+  void set property1(int i);
+  void set property2(String i);
+  void set property3(int i);
+}
+
+abstract class D3 implements D1, D2 {}
+
+abstract class D4 implements D3 {}
+
+main() {}
diff --git a/pkg/front_end/testcases/general/getter_vs_setter_type.dart.textual_outline_modelled.expect b/pkg/front_end/testcases/general/getter_vs_setter_type.dart.textual_outline_modelled.expect
new file mode 100644
index 0000000..22c0c24
--- /dev/null
+++ b/pkg/front_end/testcases/general/getter_vs_setter_type.dart.textual_outline_modelled.expect
@@ -0,0 +1,66 @@
+abstract class A {
+  String get property3;
+  covariant String property6;
+  int get property1;
+  int get property2;
+  int property4;
+  int property5;
+  void set property1(int i);
+  void set property2(int i);
+  void set property3(int i);
+}
+
+abstract class B1 {
+  B1(this.property4, this.property5, this.property6);
+  String get property3;
+  final String property6;
+  final int property4;
+  final int property5;
+  int get property1;
+  int get property2;
+}
+
+abstract class B2 implements B1 {
+  void set property1(int i);
+  void set property2(String i);
+  void set property3(int i);
+  void set property4(int i);
+  void set property5(String i);
+  void set property6(int i);
+}
+
+abstract class C1 {
+  String property5;
+  int property4;
+  int property6;
+  void set property1(int i);
+  void set property2(String i);
+  void set property3(int i);
+}
+
+abstract class C2 implements C1 {
+  String get property3;
+  String get property6;
+  int get property1;
+  int get property2;
+  int get property4;
+  int get property5;
+}
+
+abstract class D1 {
+  String get property3;
+  int get property1;
+  int get property2;
+}
+
+abstract class D2 {
+  void set property1(int i);
+  void set property2(String i);
+  void set property3(int i);
+}
+
+abstract class D3 implements D1, D2 {}
+
+abstract class D4 implements D3 {}
+
+main() {}
diff --git a/pkg/front_end/testcases/inference/infer_final_field_getter_and_setter.dart.outline.expect b/pkg/front_end/testcases/inference/infer_final_field_getter_and_setter.dart.outline.expect
index e645d8d..b9c9e68 100644
--- a/pkg/front_end/testcases/inference/infer_final_field_getter_and_setter.dart.outline.expect
+++ b/pkg/front_end/testcases/inference/infer_final_field_getter_and_setter.dart.outline.expect
@@ -1,4 +1,21 @@
 library test;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/inference/infer_final_field_getter_and_setter.dart:9:11: Error: The type 'int' of the getter 'A.x' is not assignable to the type 'double' of the setter 'A.x'.
+//   int get x;
+//           ^
+// pkg/front_end/testcases/inference/infer_final_field_getter_and_setter.dart:10:12: Context: This is the declaration of the setter 'A.x'.
+//   void set x(double value) {}
+//            ^
+//
+// pkg/front_end/testcases/inference/infer_final_field_getter_and_setter.dart:14:9: Error: The type 'int' of the field 'B.x' is not assignable to the type 'double' of the inherited setter 'A.x'.
+//   final x;
+//         ^
+// pkg/front_end/testcases/inference/infer_final_field_getter_and_setter.dart:10:12: Context: This is the declaration of the setter 'A.x'.
+//   void set x(double value) {}
+//            ^
+//
 import self as self;
 import "dart:core" as core;
 
diff --git a/pkg/front_end/testcases/inference/infer_final_field_getter_and_setter.dart.strong.expect b/pkg/front_end/testcases/inference/infer_final_field_getter_and_setter.dart.strong.expect
index 5cb9148..3eab43e 100644
--- a/pkg/front_end/testcases/inference/infer_final_field_getter_and_setter.dart.strong.expect
+++ b/pkg/front_end/testcases/inference/infer_final_field_getter_and_setter.dart.strong.expect
@@ -1,4 +1,21 @@
 library test;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/inference/infer_final_field_getter_and_setter.dart:9:11: Error: The type 'int' of the getter 'A.x' is not assignable to the type 'double' of the setter 'A.x'.
+//   int get x;
+//           ^
+// pkg/front_end/testcases/inference/infer_final_field_getter_and_setter.dart:10:12: Context: This is the declaration of the setter 'A.x'.
+//   void set x(double value) {}
+//            ^
+//
+// pkg/front_end/testcases/inference/infer_final_field_getter_and_setter.dart:14:9: Error: The type 'int' of the field 'B.x' is not assignable to the type 'double' of the inherited setter 'A.x'.
+//   final x;
+//         ^
+// pkg/front_end/testcases/inference/infer_final_field_getter_and_setter.dart:10:12: Context: This is the declaration of the setter 'A.x'.
+//   void set x(double value) {}
+//            ^
+//
 import self as self;
 import "dart:core" as core;
 
diff --git a/pkg/front_end/testcases/inference/infer_final_field_getter_and_setter.dart.strong.transformed.expect b/pkg/front_end/testcases/inference/infer_final_field_getter_and_setter.dart.strong.transformed.expect
index 5cb9148..3eab43e 100644
--- a/pkg/front_end/testcases/inference/infer_final_field_getter_and_setter.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/inference/infer_final_field_getter_and_setter.dart.strong.transformed.expect
@@ -1,4 +1,21 @@
 library test;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/inference/infer_final_field_getter_and_setter.dart:9:11: Error: The type 'int' of the getter 'A.x' is not assignable to the type 'double' of the setter 'A.x'.
+//   int get x;
+//           ^
+// pkg/front_end/testcases/inference/infer_final_field_getter_and_setter.dart:10:12: Context: This is the declaration of the setter 'A.x'.
+//   void set x(double value) {}
+//            ^
+//
+// pkg/front_end/testcases/inference/infer_final_field_getter_and_setter.dart:14:9: Error: The type 'int' of the field 'B.x' is not assignable to the type 'double' of the inherited setter 'A.x'.
+//   final x;
+//         ^
+// pkg/front_end/testcases/inference/infer_final_field_getter_and_setter.dart:10:12: Context: This is the declaration of the setter 'A.x'.
+//   void set x(double value) {}
+//            ^
+//
 import self as self;
 import "dart:core" as core;
 
diff --git a/pkg/front_end/testcases/inference_new/infer_field_getter_setter_mismatch.dart.outline.expect b/pkg/front_end/testcases/inference_new/infer_field_getter_setter_mismatch.dart.outline.expect
index 0672d55..1385117 100644
--- a/pkg/front_end/testcases/inference_new/infer_field_getter_setter_mismatch.dart.outline.expect
+++ b/pkg/front_end/testcases/inference_new/infer_field_getter_setter_mismatch.dart.outline.expect
@@ -13,6 +13,13 @@
 //   void set x(double value);
 //            ^
 //
+// pkg/front_end/testcases/inference_new/infer_field_getter_setter_mismatch.dart:9:11: Error: The type 'int' of the getter 'A.x' is not assignable to the type 'double' of the setter 'A.x'.
+//   int get x;
+//           ^
+// pkg/front_end/testcases/inference_new/infer_field_getter_setter_mismatch.dart:10:12: Context: This is the declaration of the setter 'A.x'.
+//   void set x(double value);
+//            ^
+//
 import self as self;
 import "dart:core" as core;
 
diff --git a/pkg/front_end/testcases/inference_new/infer_field_getter_setter_mismatch.dart.strong.expect b/pkg/front_end/testcases/inference_new/infer_field_getter_setter_mismatch.dart.strong.expect
index 60eda17..c0bc8d0 100644
--- a/pkg/front_end/testcases/inference_new/infer_field_getter_setter_mismatch.dart.strong.expect
+++ b/pkg/front_end/testcases/inference_new/infer_field_getter_setter_mismatch.dart.strong.expect
@@ -13,6 +13,13 @@
 //   void set x(double value);
 //            ^
 //
+// pkg/front_end/testcases/inference_new/infer_field_getter_setter_mismatch.dart:9:11: Error: The type 'int' of the getter 'A.x' is not assignable to the type 'double' of the setter 'A.x'.
+//   int get x;
+//           ^
+// pkg/front_end/testcases/inference_new/infer_field_getter_setter_mismatch.dart:10:12: Context: This is the declaration of the setter 'A.x'.
+//   void set x(double value);
+//            ^
+//
 import self as self;
 import "dart:core" as core;
 
diff --git a/pkg/front_end/testcases/inference_new/infer_field_getter_setter_mismatch.dart.strong.transformed.expect b/pkg/front_end/testcases/inference_new/infer_field_getter_setter_mismatch.dart.strong.transformed.expect
index 60eda17..c0bc8d0 100644
--- a/pkg/front_end/testcases/inference_new/infer_field_getter_setter_mismatch.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/inference_new/infer_field_getter_setter_mismatch.dart.strong.transformed.expect
@@ -13,6 +13,13 @@
 //   void set x(double value);
 //            ^
 //
+// pkg/front_end/testcases/inference_new/infer_field_getter_setter_mismatch.dart:9:11: Error: The type 'int' of the getter 'A.x' is not assignable to the type 'double' of the setter 'A.x'.
+//   int get x;
+//           ^
+// pkg/front_end/testcases/inference_new/infer_field_getter_setter_mismatch.dart:10:12: Context: This is the declaration of the setter 'A.x'.
+//   void set x(double value);
+//            ^
+//
 import self as self;
 import "dart:core" as core;
 
diff --git a/pkg/front_end/testcases/inference_new/property_assign_combiner.dart.outline.expect b/pkg/front_end/testcases/inference_new/property_assign_combiner.dart.outline.expect
index d0171ae..1dedb62 100644
--- a/pkg/front_end/testcases/inference_new/property_assign_combiner.dart.outline.expect
+++ b/pkg/front_end/testcases/inference_new/property_assign_combiner.dart.outline.expect
@@ -1,4 +1,16 @@
 library test;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/inference_new/property_assign_combiner.dart:29:9: Error: The type 'A' of the getter 'G.target' is not assignable to the type 'B' of the setter 'G.target'.
+//  - 'A' is from 'pkg/front_end/testcases/inference_new/property_assign_combiner.dart'.
+//  - 'B' is from 'pkg/front_end/testcases/inference_new/property_assign_combiner.dart'.
+//   A get target => null;
+//         ^^^^^^
+// pkg/front_end/testcases/inference_new/property_assign_combiner.dart:31:12: Context: This is the declaration of the setter 'G.target'.
+//   void set target(B value) {}
+//            ^^^^^^
+//
 import self as self;
 import "dart:core" as core;
 
diff --git a/pkg/front_end/testcases/inference_new/property_assign_combiner.dart.strong.expect b/pkg/front_end/testcases/inference_new/property_assign_combiner.dart.strong.expect
index 165d38e..b551bed 100644
--- a/pkg/front_end/testcases/inference_new/property_assign_combiner.dart.strong.expect
+++ b/pkg/front_end/testcases/inference_new/property_assign_combiner.dart.strong.expect
@@ -1,4 +1,16 @@
 library test;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/inference_new/property_assign_combiner.dart:29:9: Error: The type 'A' of the getter 'G.target' is not assignable to the type 'B' of the setter 'G.target'.
+//  - 'A' is from 'pkg/front_end/testcases/inference_new/property_assign_combiner.dart'.
+//  - 'B' is from 'pkg/front_end/testcases/inference_new/property_assign_combiner.dart'.
+//   A get target => null;
+//         ^^^^^^
+// pkg/front_end/testcases/inference_new/property_assign_combiner.dart:31:12: Context: This is the declaration of the setter 'G.target'.
+//   void set target(B value) {}
+//            ^^^^^^
+//
 import self as self;
 import "dart:core" as core;
 
diff --git a/pkg/front_end/testcases/inference_new/property_assign_combiner.dart.strong.transformed.expect b/pkg/front_end/testcases/inference_new/property_assign_combiner.dart.strong.transformed.expect
index 165d38e..b551bed 100644
--- a/pkg/front_end/testcases/inference_new/property_assign_combiner.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/inference_new/property_assign_combiner.dart.strong.transformed.expect
@@ -1,4 +1,16 @@
 library test;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/inference_new/property_assign_combiner.dart:29:9: Error: The type 'A' of the getter 'G.target' is not assignable to the type 'B' of the setter 'G.target'.
+//  - 'A' is from 'pkg/front_end/testcases/inference_new/property_assign_combiner.dart'.
+//  - 'B' is from 'pkg/front_end/testcases/inference_new/property_assign_combiner.dart'.
+//   A get target => null;
+//         ^^^^^^
+// pkg/front_end/testcases/inference_new/property_assign_combiner.dart:31:12: Context: This is the declaration of the setter 'G.target'.
+//   void set target(B value) {}
+//            ^^^^^^
+//
 import self as self;
 import "dart:core" as core;
 
diff --git a/pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart b/pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart
new file mode 100644
index 0000000..90ac015
--- /dev/null
+++ b/pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart
@@ -0,0 +1,55 @@
+// 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.
+
+abstract class A {
+  late int property4; // ok
+
+  late int? property5; // ok
+
+  covariant late int property6; // ok
+
+  A(this.property4, this.property5, this.property6);
+}
+
+abstract class B1 {
+  late final int property4;
+
+  late final int property5;
+
+  late final int? property6;
+
+  B1(this.property4, this.property5, this.property6);
+}
+
+abstract class B2 implements B1 {
+  void set property4(int i); // ok
+
+  void set property5(int? i); // ok
+
+  // This results in two errors; one for the getter/setter type mismatch and one
+  // for the getter override.
+  void set property6(int i); // error
+}
+
+abstract class C1 {
+  late int property4;
+
+  late int property5;
+
+  late int property6;
+
+  C1(this.property4, this.property5, this.property6);
+}
+
+abstract class C2 implements C1 {
+  int get property4; // ok
+
+  int get property5; // ok
+
+  // This results in two errors; one for the getter/setter type mismatch and one
+  // for the getter override.
+  int? get property6; // error
+}
+
+main() {}
diff --git a/pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart.outline.expect b/pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart.outline.expect
new file mode 100644
index 0000000..7c87b5f
--- /dev/null
+++ b/pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart.outline.expect
@@ -0,0 +1,94 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart:32:26: Error: The parameter 'i' of the method 'B2.property6' has type 'int', which does not match the corresponding type, 'int?', in the overridden method, 'B1.property6'.
+// Change to a supertype of 'int?', or, for a covariant parameter, a subtype.
+//   void set property6(int i); // error
+//                          ^
+// pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart:20:19: Context: This is the overridden method ('property6').
+//   late final int? property6;
+//                   ^
+//
+// pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart:32:12: Error: The type 'int?' of the inherited getter 'B1.property6' is not a subtype of the type 'int' of the setter 'B2.property6'.
+//   void set property6(int i); // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart:20:19: Context: This is the declaration of the getter 'B1.property6'.
+//   late final int? property6;
+//                   ^^^^^^^^^
+//
+// pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart:52:12: Error: The return type of the method 'C2.property6' is 'int?', which does not match the return type, 'int', of the overridden method, 'C1.property6'.
+// Change to a subtype of 'int'.
+//   int? get property6; // error
+//            ^
+// pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart:40:12: Context: This is the overridden method ('property6').
+//   late int property6;
+//            ^
+//
+// pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart:52:12: Error: The type 'int?' of the getter 'C2.property6' is not a subtype of the type 'int' of the inherited setter 'C1.property6'.
+//   int? get property6; // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart:40:12: Context: This is the declaration of the setter 'C1.property6'.
+//   late int property6;
+//            ^^^^^^^^^
+//
+import self as self;
+import "dart:core" as core;
+
+abstract class A extends core::Object {
+  field core::int? _#A#property4;
+  field core::int? _#A#property5;
+  field core::bool _#A#property5#isSet;
+  field core::int? _#A#property6;
+  constructor •(core::int property4, core::int? property5, core::int property6) → self::A
+    ;
+  get property4() → core::int;
+  set property4(core::int #t1) → void;
+  get property5() → core::int?;
+  set property5(core::int? #t2) → void;
+  get property6() → core::int;
+  set property6(covariant core::int #t3) → void;
+}
+abstract class B1 extends core::Object {
+  field core::int? _#B1#property4;
+  field core::int? _#B1#property5;
+  field core::int? _#B1#property6;
+  field core::bool _#B1#property6#isSet;
+  constructor •(core::int property4, core::int property5, core::int? property6) → self::B1
+    ;
+  get property4() → core::int;
+  set property4(core::int #t4) → void;
+  get property5() → core::int;
+  set property5(core::int #t5) → void;
+  get property6() → core::int?;
+  set property6(core::int? #t6) → void;
+}
+abstract class B2 extends core::Object implements self::B1 {
+  synthetic constructor •() → self::B2
+    ;
+  abstract set property4(core::int i) → void;
+  abstract set property5(core::int? i) → void;
+  abstract set property6(core::int i) → void;
+}
+abstract class C1 extends core::Object {
+  field core::int? _#C1#property4;
+  field core::int? _#C1#property5;
+  field core::int? _#C1#property6;
+  constructor •(core::int property4, core::int property5, core::int property6) → self::C1
+    ;
+  get property4() → core::int;
+  set property4(core::int #t7) → void;
+  get property5() → core::int;
+  set property5(core::int #t8) → void;
+  get property6() → core::int;
+  set property6(core::int #t9) → void;
+}
+abstract class C2 extends core::Object implements self::C1 {
+  synthetic constructor •() → self::C2
+    ;
+  abstract get property4() → core::int;
+  abstract get property5() → core::int;
+  abstract get property6() → core::int?;
+}
+static method main() → dynamic
+  ;
diff --git a/pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart.strong.expect b/pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart.strong.expect
new file mode 100644
index 0000000..9248820
--- /dev/null
+++ b/pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart.strong.expect
@@ -0,0 +1,130 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart:32:26: Error: The parameter 'i' of the method 'B2.property6' has type 'int', which does not match the corresponding type, 'int?', in the overridden method, 'B1.property6'.
+// Change to a supertype of 'int?', or, for a covariant parameter, a subtype.
+//   void set property6(int i); // error
+//                          ^
+// pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart:20:19: Context: This is the overridden method ('property6').
+//   late final int? property6;
+//                   ^
+//
+// pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart:32:12: Error: The type 'int?' of the inherited getter 'B1.property6' is not a subtype of the type 'int' of the setter 'B2.property6'.
+//   void set property6(int i); // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart:20:19: Context: This is the declaration of the getter 'B1.property6'.
+//   late final int? property6;
+//                   ^^^^^^^^^
+//
+// pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart:52:12: Error: The return type of the method 'C2.property6' is 'int?', which does not match the return type, 'int', of the overridden method, 'C1.property6'.
+// Change to a subtype of 'int'.
+//   int? get property6; // error
+//            ^
+// pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart:40:12: Context: This is the overridden method ('property6').
+//   late int property6;
+//            ^
+//
+// pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart:52:12: Error: The type 'int?' of the getter 'C2.property6' is not a subtype of the type 'int' of the inherited setter 'C1.property6'.
+//   int? get property6; // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart:40:12: Context: This is the declaration of the setter 'C1.property6'.
+//   late int property6;
+//            ^^^^^^^^^
+//
+import self as self;
+import "dart:core" as core;
+import "dart:_internal" as _in;
+
+abstract class A extends core::Object {
+  field core::int? _#A#property4 = null;
+  field core::int? _#A#property5 = null;
+  field core::bool _#A#property5#isSet = false;
+  field core::int? _#A#property6 = null;
+  constructor •(core::int property4, core::int? property5, core::int property6) → self::A
+    : self::A::_#A#property4 = property4, self::A::_#A#property5#isSet = true, self::A::_#A#property5 = property5, self::A::_#A#property6 = property6, super core::Object::•()
+    ;
+  get property4() → core::int
+    return let final core::int? #t1 = this.{self::A::_#A#property4} in #t1.==(null) ?{core::int} throw new _in::LateInitializationErrorImpl::•("Field 'property4' has not been initialized.") : #t1{core::int};
+  set property4(core::int #t2) → void
+    this.{self::A::_#A#property4} = #t2;
+  get property5() → core::int?
+    return this.{self::A::_#A#property5#isSet} ?{core::int?} this.{self::A::_#A#property5} : throw new _in::LateInitializationErrorImpl::•("Field 'property5' has not been initialized.");
+  set property5(core::int? #t3) → void {
+    this.{self::A::_#A#property5#isSet} = true;
+    this.{self::A::_#A#property5} = #t3;
+  }
+  get property6() → core::int
+    return let final core::int? #t4 = this.{self::A::_#A#property6} in #t4.==(null) ?{core::int} throw new _in::LateInitializationErrorImpl::•("Field 'property6' has not been initialized.") : #t4{core::int};
+  set property6(covariant core::int #t5) → void
+    this.{self::A::_#A#property6} = #t5;
+}
+abstract class B1 extends core::Object {
+  field core::int? _#B1#property4 = null;
+  field core::int? _#B1#property5 = null;
+  field core::int? _#B1#property6 = null;
+  field core::bool _#B1#property6#isSet = false;
+  constructor •(core::int property4, core::int property5, core::int? property6) → self::B1
+    : self::B1::_#B1#property4 = property4, self::B1::_#B1#property5 = property5, self::B1::_#B1#property6#isSet = true, self::B1::_#B1#property6 = property6, super core::Object::•()
+    ;
+  get property4() → core::int
+    return let final core::int? #t6 = this.{self::B1::_#B1#property4} in #t6.==(null) ?{core::int} throw new _in::LateInitializationErrorImpl::•("Field 'property4' has not been initialized.") : #t6{core::int};
+  set property4(core::int #t7) → void
+    if(this.{self::B1::_#B1#property4}.==(null))
+      this.{self::B1::_#B1#property4} = #t7;
+    else
+      throw new _in::LateInitializationErrorImpl::•("Field 'property4' has already been initialized.");
+  get property5() → core::int
+    return let final core::int? #t8 = this.{self::B1::_#B1#property5} in #t8.==(null) ?{core::int} throw new _in::LateInitializationErrorImpl::•("Field 'property5' has not been initialized.") : #t8{core::int};
+  set property5(core::int #t9) → void
+    if(this.{self::B1::_#B1#property5}.==(null))
+      this.{self::B1::_#B1#property5} = #t9;
+    else
+      throw new _in::LateInitializationErrorImpl::•("Field 'property5' has already been initialized.");
+  get property6() → core::int?
+    return this.{self::B1::_#B1#property6#isSet} ?{core::int?} this.{self::B1::_#B1#property6} : throw new _in::LateInitializationErrorImpl::•("Field 'property6' has not been initialized.");
+  set property6(core::int? #t10) → void
+    if(this.{self::B1::_#B1#property6#isSet})
+      throw new _in::LateInitializationErrorImpl::•("Field 'property6' has already been initialized.");
+    else {
+      this.{self::B1::_#B1#property6#isSet} = true;
+      this.{self::B1::_#B1#property6} = #t10;
+    }
+}
+abstract class B2 extends core::Object implements self::B1 {
+  synthetic constructor •() → self::B2
+    : super core::Object::•()
+    ;
+  abstract set property4(core::int i) → void;
+  abstract set property5(core::int? i) → void;
+  abstract set property6(core::int i) → void;
+}
+abstract class C1 extends core::Object {
+  field core::int? _#C1#property4 = null;
+  field core::int? _#C1#property5 = null;
+  field core::int? _#C1#property6 = null;
+  constructor •(core::int property4, core::int property5, core::int property6) → self::C1
+    : self::C1::_#C1#property4 = property4, self::C1::_#C1#property5 = property5, self::C1::_#C1#property6 = property6, super core::Object::•()
+    ;
+  get property4() → core::int
+    return let final core::int? #t11 = this.{self::C1::_#C1#property4} in #t11.==(null) ?{core::int} throw new _in::LateInitializationErrorImpl::•("Field 'property4' has not been initialized.") : #t11{core::int};
+  set property4(core::int #t12) → void
+    this.{self::C1::_#C1#property4} = #t12;
+  get property5() → core::int
+    return let final core::int? #t13 = this.{self::C1::_#C1#property5} in #t13.==(null) ?{core::int} throw new _in::LateInitializationErrorImpl::•("Field 'property5' has not been initialized.") : #t13{core::int};
+  set property5(core::int #t14) → void
+    this.{self::C1::_#C1#property5} = #t14;
+  get property6() → core::int
+    return let final core::int? #t15 = this.{self::C1::_#C1#property6} in #t15.==(null) ?{core::int} throw new _in::LateInitializationErrorImpl::•("Field 'property6' has not been initialized.") : #t15{core::int};
+  set property6(core::int #t16) → void
+    this.{self::C1::_#C1#property6} = #t16;
+}
+abstract class C2 extends core::Object implements self::C1 {
+  synthetic constructor •() → self::C2
+    : super core::Object::•()
+    ;
+  abstract get property4() → core::int;
+  abstract get property5() → core::int;
+  abstract get property6() → core::int?;
+}
+static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart.strong.transformed.expect b/pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart.strong.transformed.expect
new file mode 100644
index 0000000..9248820
--- /dev/null
+++ b/pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart.strong.transformed.expect
@@ -0,0 +1,130 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart:32:26: Error: The parameter 'i' of the method 'B2.property6' has type 'int', which does not match the corresponding type, 'int?', in the overridden method, 'B1.property6'.
+// Change to a supertype of 'int?', or, for a covariant parameter, a subtype.
+//   void set property6(int i); // error
+//                          ^
+// pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart:20:19: Context: This is the overridden method ('property6').
+//   late final int? property6;
+//                   ^
+//
+// pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart:32:12: Error: The type 'int?' of the inherited getter 'B1.property6' is not a subtype of the type 'int' of the setter 'B2.property6'.
+//   void set property6(int i); // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart:20:19: Context: This is the declaration of the getter 'B1.property6'.
+//   late final int? property6;
+//                   ^^^^^^^^^
+//
+// pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart:52:12: Error: The return type of the method 'C2.property6' is 'int?', which does not match the return type, 'int', of the overridden method, 'C1.property6'.
+// Change to a subtype of 'int'.
+//   int? get property6; // error
+//            ^
+// pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart:40:12: Context: This is the overridden method ('property6').
+//   late int property6;
+//            ^
+//
+// pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart:52:12: Error: The type 'int?' of the getter 'C2.property6' is not a subtype of the type 'int' of the inherited setter 'C1.property6'.
+//   int? get property6; // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart:40:12: Context: This is the declaration of the setter 'C1.property6'.
+//   late int property6;
+//            ^^^^^^^^^
+//
+import self as self;
+import "dart:core" as core;
+import "dart:_internal" as _in;
+
+abstract class A extends core::Object {
+  field core::int? _#A#property4 = null;
+  field core::int? _#A#property5 = null;
+  field core::bool _#A#property5#isSet = false;
+  field core::int? _#A#property6 = null;
+  constructor •(core::int property4, core::int? property5, core::int property6) → self::A
+    : self::A::_#A#property4 = property4, self::A::_#A#property5#isSet = true, self::A::_#A#property5 = property5, self::A::_#A#property6 = property6, super core::Object::•()
+    ;
+  get property4() → core::int
+    return let final core::int? #t1 = this.{self::A::_#A#property4} in #t1.==(null) ?{core::int} throw new _in::LateInitializationErrorImpl::•("Field 'property4' has not been initialized.") : #t1{core::int};
+  set property4(core::int #t2) → void
+    this.{self::A::_#A#property4} = #t2;
+  get property5() → core::int?
+    return this.{self::A::_#A#property5#isSet} ?{core::int?} this.{self::A::_#A#property5} : throw new _in::LateInitializationErrorImpl::•("Field 'property5' has not been initialized.");
+  set property5(core::int? #t3) → void {
+    this.{self::A::_#A#property5#isSet} = true;
+    this.{self::A::_#A#property5} = #t3;
+  }
+  get property6() → core::int
+    return let final core::int? #t4 = this.{self::A::_#A#property6} in #t4.==(null) ?{core::int} throw new _in::LateInitializationErrorImpl::•("Field 'property6' has not been initialized.") : #t4{core::int};
+  set property6(covariant core::int #t5) → void
+    this.{self::A::_#A#property6} = #t5;
+}
+abstract class B1 extends core::Object {
+  field core::int? _#B1#property4 = null;
+  field core::int? _#B1#property5 = null;
+  field core::int? _#B1#property6 = null;
+  field core::bool _#B1#property6#isSet = false;
+  constructor •(core::int property4, core::int property5, core::int? property6) → self::B1
+    : self::B1::_#B1#property4 = property4, self::B1::_#B1#property5 = property5, self::B1::_#B1#property6#isSet = true, self::B1::_#B1#property6 = property6, super core::Object::•()
+    ;
+  get property4() → core::int
+    return let final core::int? #t6 = this.{self::B1::_#B1#property4} in #t6.==(null) ?{core::int} throw new _in::LateInitializationErrorImpl::•("Field 'property4' has not been initialized.") : #t6{core::int};
+  set property4(core::int #t7) → void
+    if(this.{self::B1::_#B1#property4}.==(null))
+      this.{self::B1::_#B1#property4} = #t7;
+    else
+      throw new _in::LateInitializationErrorImpl::•("Field 'property4' has already been initialized.");
+  get property5() → core::int
+    return let final core::int? #t8 = this.{self::B1::_#B1#property5} in #t8.==(null) ?{core::int} throw new _in::LateInitializationErrorImpl::•("Field 'property5' has not been initialized.") : #t8{core::int};
+  set property5(core::int #t9) → void
+    if(this.{self::B1::_#B1#property5}.==(null))
+      this.{self::B1::_#B1#property5} = #t9;
+    else
+      throw new _in::LateInitializationErrorImpl::•("Field 'property5' has already been initialized.");
+  get property6() → core::int?
+    return this.{self::B1::_#B1#property6#isSet} ?{core::int?} this.{self::B1::_#B1#property6} : throw new _in::LateInitializationErrorImpl::•("Field 'property6' has not been initialized.");
+  set property6(core::int? #t10) → void
+    if(this.{self::B1::_#B1#property6#isSet})
+      throw new _in::LateInitializationErrorImpl::•("Field 'property6' has already been initialized.");
+    else {
+      this.{self::B1::_#B1#property6#isSet} = true;
+      this.{self::B1::_#B1#property6} = #t10;
+    }
+}
+abstract class B2 extends core::Object implements self::B1 {
+  synthetic constructor •() → self::B2
+    : super core::Object::•()
+    ;
+  abstract set property4(core::int i) → void;
+  abstract set property5(core::int? i) → void;
+  abstract set property6(core::int i) → void;
+}
+abstract class C1 extends core::Object {
+  field core::int? _#C1#property4 = null;
+  field core::int? _#C1#property5 = null;
+  field core::int? _#C1#property6 = null;
+  constructor •(core::int property4, core::int property5, core::int property6) → self::C1
+    : self::C1::_#C1#property4 = property4, self::C1::_#C1#property5 = property5, self::C1::_#C1#property6 = property6, super core::Object::•()
+    ;
+  get property4() → core::int
+    return let final core::int? #t11 = this.{self::C1::_#C1#property4} in #t11.==(null) ?{core::int} throw new _in::LateInitializationErrorImpl::•("Field 'property4' has not been initialized.") : #t11{core::int};
+  set property4(core::int #t12) → void
+    this.{self::C1::_#C1#property4} = #t12;
+  get property5() → core::int
+    return let final core::int? #t13 = this.{self::C1::_#C1#property5} in #t13.==(null) ?{core::int} throw new _in::LateInitializationErrorImpl::•("Field 'property5' has not been initialized.") : #t13{core::int};
+  set property5(core::int #t14) → void
+    this.{self::C1::_#C1#property5} = #t14;
+  get property6() → core::int
+    return let final core::int? #t15 = this.{self::C1::_#C1#property6} in #t15.==(null) ?{core::int} throw new _in::LateInitializationErrorImpl::•("Field 'property6' has not been initialized.") : #t15{core::int};
+  set property6(core::int #t16) → void
+    this.{self::C1::_#C1#property6} = #t16;
+}
+abstract class C2 extends core::Object implements self::C1 {
+  synthetic constructor •() → self::C2
+    : super core::Object::•()
+    ;
+  abstract get property4() → core::int;
+  abstract get property5() → core::int;
+  abstract get property6() → core::int?;
+}
+static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart.textual_outline.expect b/pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart.textual_outline.expect
new file mode 100644
index 0000000..2045647
--- /dev/null
+++ b/pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart.textual_outline.expect
@@ -0,0 +1,39 @@
+abstract class A {
+  late int ;
+  property4;
+  late int;
+  operator? (){}
+  property5;
+  covariant late int ;
+  property6;
+  A(this.property4, this.property5, this.property6);
+}
+abstract class B1 {
+  late ;
+  final int property4;
+  late ;
+  final int property5;
+  late ;
+  final int? property6;
+  B1(this.property4, this.property5, this.property6);
+}
+abstract class B2 implements B1 {
+  void set property4(int i);
+  void set property5(int? i);
+  void set property6(int i);
+}
+abstract class C1 {
+  late int ;
+  property4;
+  late int ;
+  property5;
+  late int ;
+  property6;
+  C1(this.property4, this.property5, this.property6);
+}
+abstract class C2 implements C1 {
+  int get property4;
+  int get property5;
+  int? get property6;
+}
+main() {}
diff --git a/pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart.weak.expect b/pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart.weak.expect
new file mode 100644
index 0000000..7dd79a4
--- /dev/null
+++ b/pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart.weak.expect
@@ -0,0 +1,151 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart:32:26: Error: The parameter 'i' of the method 'B2.property6' has type 'int', which does not match the corresponding type, 'int?', in the overridden method, 'B1.property6'.
+// Change to a supertype of 'int?', or, for a covariant parameter, a subtype.
+//   void set property6(int i); // error
+//                          ^
+// pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart:20:19: Context: This is the overridden method ('property6').
+//   late final int? property6;
+//                   ^
+//
+// pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart:32:12: Error: The type 'int?' of the inherited getter 'B1.property6' is not a subtype of the type 'int' of the setter 'B2.property6'.
+//   void set property6(int i); // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart:20:19: Context: This is the declaration of the getter 'B1.property6'.
+//   late final int? property6;
+//                   ^^^^^^^^^
+//
+// pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart:52:12: Error: The return type of the method 'C2.property6' is 'int?', which does not match the return type, 'int', of the overridden method, 'C1.property6'.
+// Change to a subtype of 'int'.
+//   int? get property6; // error
+//            ^
+// pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart:40:12: Context: This is the overridden method ('property6').
+//   late int property6;
+//            ^
+//
+// pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart:52:12: Error: The type 'int?' of the getter 'C2.property6' is not a subtype of the type 'int' of the inherited setter 'C1.property6'.
+//   int? get property6; // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart:40:12: Context: This is the declaration of the setter 'C1.property6'.
+//   late int property6;
+//            ^^^^^^^^^
+//
+import self as self;
+import "dart:core" as core;
+import "dart:_internal" as _in;
+
+abstract class A extends core::Object {
+  field core::int? _#A#property4 = null;
+  field core::bool _#A#property4#isSet = false;
+  field core::int? _#A#property5 = null;
+  field core::bool _#A#property5#isSet = false;
+  field core::int? _#A#property6 = null;
+  field core::bool _#A#property6#isSet = false;
+  constructor •(core::int property4, core::int? property5, core::int property6) → self::A
+    : self::A::_#A#property4#isSet = true, self::A::_#A#property4 = property4, self::A::_#A#property5#isSet = true, self::A::_#A#property5 = property5, self::A::_#A#property6#isSet = true, self::A::_#A#property6 = property6, super core::Object::•()
+    ;
+  get property4() → core::int
+    return this.{self::A::_#A#property4#isSet} ?{core::int} let final core::int? #t1 = this.{self::A::_#A#property4} in #t1{core::int} : throw new _in::LateInitializationErrorImpl::•("Field 'property4' has not been initialized.");
+  set property4(core::int #t2) → void {
+    this.{self::A::_#A#property4#isSet} = true;
+    this.{self::A::_#A#property4} = #t2;
+  }
+  get property5() → core::int?
+    return this.{self::A::_#A#property5#isSet} ?{core::int?} this.{self::A::_#A#property5} : throw new _in::LateInitializationErrorImpl::•("Field 'property5' has not been initialized.");
+  set property5(core::int? #t3) → void {
+    this.{self::A::_#A#property5#isSet} = true;
+    this.{self::A::_#A#property5} = #t3;
+  }
+  get property6() → core::int
+    return this.{self::A::_#A#property6#isSet} ?{core::int} let final core::int? #t4 = this.{self::A::_#A#property6} in #t4{core::int} : throw new _in::LateInitializationErrorImpl::•("Field 'property6' has not been initialized.");
+  set property6(covariant core::int #t5) → void {
+    this.{self::A::_#A#property6#isSet} = true;
+    this.{self::A::_#A#property6} = #t5;
+  }
+}
+abstract class B1 extends core::Object {
+  field core::int? _#B1#property4 = null;
+  field core::bool _#B1#property4#isSet = false;
+  field core::int? _#B1#property5 = null;
+  field core::bool _#B1#property5#isSet = false;
+  field core::int? _#B1#property6 = null;
+  field core::bool _#B1#property6#isSet = false;
+  constructor •(core::int property4, core::int property5, core::int? property6) → self::B1
+    : self::B1::_#B1#property4#isSet = true, self::B1::_#B1#property4 = property4, self::B1::_#B1#property5#isSet = true, self::B1::_#B1#property5 = property5, self::B1::_#B1#property6#isSet = true, self::B1::_#B1#property6 = property6, super core::Object::•()
+    ;
+  get property4() → core::int
+    return this.{self::B1::_#B1#property4#isSet} ?{core::int} let final core::int? #t6 = this.{self::B1::_#B1#property4} in #t6{core::int} : throw new _in::LateInitializationErrorImpl::•("Field 'property4' has not been initialized.");
+  set property4(core::int #t7) → void
+    if(this.{self::B1::_#B1#property4#isSet})
+      throw new _in::LateInitializationErrorImpl::•("Field 'property4' has already been initialized.");
+    else {
+      this.{self::B1::_#B1#property4#isSet} = true;
+      this.{self::B1::_#B1#property4} = #t7;
+    }
+  get property5() → core::int
+    return this.{self::B1::_#B1#property5#isSet} ?{core::int} let final core::int? #t8 = this.{self::B1::_#B1#property5} in #t8{core::int} : throw new _in::LateInitializationErrorImpl::•("Field 'property5' has not been initialized.");
+  set property5(core::int #t9) → void
+    if(this.{self::B1::_#B1#property5#isSet})
+      throw new _in::LateInitializationErrorImpl::•("Field 'property5' has already been initialized.");
+    else {
+      this.{self::B1::_#B1#property5#isSet} = true;
+      this.{self::B1::_#B1#property5} = #t9;
+    }
+  get property6() → core::int?
+    return this.{self::B1::_#B1#property6#isSet} ?{core::int?} this.{self::B1::_#B1#property6} : throw new _in::LateInitializationErrorImpl::•("Field 'property6' has not been initialized.");
+  set property6(core::int? #t10) → void
+    if(this.{self::B1::_#B1#property6#isSet})
+      throw new _in::LateInitializationErrorImpl::•("Field 'property6' has already been initialized.");
+    else {
+      this.{self::B1::_#B1#property6#isSet} = true;
+      this.{self::B1::_#B1#property6} = #t10;
+    }
+}
+abstract class B2 extends core::Object implements self::B1 {
+  synthetic constructor •() → self::B2
+    : super core::Object::•()
+    ;
+  abstract set property4(core::int i) → void;
+  abstract set property5(core::int? i) → void;
+  abstract set property6(core::int i) → void;
+}
+abstract class C1 extends core::Object {
+  field core::int? _#C1#property4 = null;
+  field core::bool _#C1#property4#isSet = false;
+  field core::int? _#C1#property5 = null;
+  field core::bool _#C1#property5#isSet = false;
+  field core::int? _#C1#property6 = null;
+  field core::bool _#C1#property6#isSet = false;
+  constructor •(core::int property4, core::int property5, core::int property6) → self::C1
+    : self::C1::_#C1#property4#isSet = true, self::C1::_#C1#property4 = property4, self::C1::_#C1#property5#isSet = true, self::C1::_#C1#property5 = property5, self::C1::_#C1#property6#isSet = true, self::C1::_#C1#property6 = property6, super core::Object::•()
+    ;
+  get property4() → core::int
+    return this.{self::C1::_#C1#property4#isSet} ?{core::int} let final core::int? #t11 = this.{self::C1::_#C1#property4} in #t11{core::int} : throw new _in::LateInitializationErrorImpl::•("Field 'property4' has not been initialized.");
+  set property4(core::int #t12) → void {
+    this.{self::C1::_#C1#property4#isSet} = true;
+    this.{self::C1::_#C1#property4} = #t12;
+  }
+  get property5() → core::int
+    return this.{self::C1::_#C1#property5#isSet} ?{core::int} let final core::int? #t13 = this.{self::C1::_#C1#property5} in #t13{core::int} : throw new _in::LateInitializationErrorImpl::•("Field 'property5' has not been initialized.");
+  set property5(core::int #t14) → void {
+    this.{self::C1::_#C1#property5#isSet} = true;
+    this.{self::C1::_#C1#property5} = #t14;
+  }
+  get property6() → core::int
+    return this.{self::C1::_#C1#property6#isSet} ?{core::int} let final core::int? #t15 = this.{self::C1::_#C1#property6} in #t15{core::int} : throw new _in::LateInitializationErrorImpl::•("Field 'property6' has not been initialized.");
+  set property6(core::int #t16) → void {
+    this.{self::C1::_#C1#property6#isSet} = true;
+    this.{self::C1::_#C1#property6} = #t16;
+  }
+}
+abstract class C2 extends core::Object implements self::C1 {
+  synthetic constructor •() → self::C2
+    : super core::Object::•()
+    ;
+  abstract get property4() → core::int;
+  abstract get property5() → core::int;
+  abstract get property6() → core::int?;
+}
+static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart.weak.transformed.expect b/pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart.weak.transformed.expect
new file mode 100644
index 0000000..7dd79a4
--- /dev/null
+++ b/pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart.weak.transformed.expect
@@ -0,0 +1,151 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart:32:26: Error: The parameter 'i' of the method 'B2.property6' has type 'int', which does not match the corresponding type, 'int?', in the overridden method, 'B1.property6'.
+// Change to a supertype of 'int?', or, for a covariant parameter, a subtype.
+//   void set property6(int i); // error
+//                          ^
+// pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart:20:19: Context: This is the overridden method ('property6').
+//   late final int? property6;
+//                   ^
+//
+// pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart:32:12: Error: The type 'int?' of the inherited getter 'B1.property6' is not a subtype of the type 'int' of the setter 'B2.property6'.
+//   void set property6(int i); // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart:20:19: Context: This is the declaration of the getter 'B1.property6'.
+//   late final int? property6;
+//                   ^^^^^^^^^
+//
+// pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart:52:12: Error: The return type of the method 'C2.property6' is 'int?', which does not match the return type, 'int', of the overridden method, 'C1.property6'.
+// Change to a subtype of 'int'.
+//   int? get property6; // error
+//            ^
+// pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart:40:12: Context: This is the overridden method ('property6').
+//   late int property6;
+//            ^
+//
+// pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart:52:12: Error: The type 'int?' of the getter 'C2.property6' is not a subtype of the type 'int' of the inherited setter 'C1.property6'.
+//   int? get property6; // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/late_lowering/getter_vs_setter_type.dart:40:12: Context: This is the declaration of the setter 'C1.property6'.
+//   late int property6;
+//            ^^^^^^^^^
+//
+import self as self;
+import "dart:core" as core;
+import "dart:_internal" as _in;
+
+abstract class A extends core::Object {
+  field core::int? _#A#property4 = null;
+  field core::bool _#A#property4#isSet = false;
+  field core::int? _#A#property5 = null;
+  field core::bool _#A#property5#isSet = false;
+  field core::int? _#A#property6 = null;
+  field core::bool _#A#property6#isSet = false;
+  constructor •(core::int property4, core::int? property5, core::int property6) → self::A
+    : self::A::_#A#property4#isSet = true, self::A::_#A#property4 = property4, self::A::_#A#property5#isSet = true, self::A::_#A#property5 = property5, self::A::_#A#property6#isSet = true, self::A::_#A#property6 = property6, super core::Object::•()
+    ;
+  get property4() → core::int
+    return this.{self::A::_#A#property4#isSet} ?{core::int} let final core::int? #t1 = this.{self::A::_#A#property4} in #t1{core::int} : throw new _in::LateInitializationErrorImpl::•("Field 'property4' has not been initialized.");
+  set property4(core::int #t2) → void {
+    this.{self::A::_#A#property4#isSet} = true;
+    this.{self::A::_#A#property4} = #t2;
+  }
+  get property5() → core::int?
+    return this.{self::A::_#A#property5#isSet} ?{core::int?} this.{self::A::_#A#property5} : throw new _in::LateInitializationErrorImpl::•("Field 'property5' has not been initialized.");
+  set property5(core::int? #t3) → void {
+    this.{self::A::_#A#property5#isSet} = true;
+    this.{self::A::_#A#property5} = #t3;
+  }
+  get property6() → core::int
+    return this.{self::A::_#A#property6#isSet} ?{core::int} let final core::int? #t4 = this.{self::A::_#A#property6} in #t4{core::int} : throw new _in::LateInitializationErrorImpl::•("Field 'property6' has not been initialized.");
+  set property6(covariant core::int #t5) → void {
+    this.{self::A::_#A#property6#isSet} = true;
+    this.{self::A::_#A#property6} = #t5;
+  }
+}
+abstract class B1 extends core::Object {
+  field core::int? _#B1#property4 = null;
+  field core::bool _#B1#property4#isSet = false;
+  field core::int? _#B1#property5 = null;
+  field core::bool _#B1#property5#isSet = false;
+  field core::int? _#B1#property6 = null;
+  field core::bool _#B1#property6#isSet = false;
+  constructor •(core::int property4, core::int property5, core::int? property6) → self::B1
+    : self::B1::_#B1#property4#isSet = true, self::B1::_#B1#property4 = property4, self::B1::_#B1#property5#isSet = true, self::B1::_#B1#property5 = property5, self::B1::_#B1#property6#isSet = true, self::B1::_#B1#property6 = property6, super core::Object::•()
+    ;
+  get property4() → core::int
+    return this.{self::B1::_#B1#property4#isSet} ?{core::int} let final core::int? #t6 = this.{self::B1::_#B1#property4} in #t6{core::int} : throw new _in::LateInitializationErrorImpl::•("Field 'property4' has not been initialized.");
+  set property4(core::int #t7) → void
+    if(this.{self::B1::_#B1#property4#isSet})
+      throw new _in::LateInitializationErrorImpl::•("Field 'property4' has already been initialized.");
+    else {
+      this.{self::B1::_#B1#property4#isSet} = true;
+      this.{self::B1::_#B1#property4} = #t7;
+    }
+  get property5() → core::int
+    return this.{self::B1::_#B1#property5#isSet} ?{core::int} let final core::int? #t8 = this.{self::B1::_#B1#property5} in #t8{core::int} : throw new _in::LateInitializationErrorImpl::•("Field 'property5' has not been initialized.");
+  set property5(core::int #t9) → void
+    if(this.{self::B1::_#B1#property5#isSet})
+      throw new _in::LateInitializationErrorImpl::•("Field 'property5' has already been initialized.");
+    else {
+      this.{self::B1::_#B1#property5#isSet} = true;
+      this.{self::B1::_#B1#property5} = #t9;
+    }
+  get property6() → core::int?
+    return this.{self::B1::_#B1#property6#isSet} ?{core::int?} this.{self::B1::_#B1#property6} : throw new _in::LateInitializationErrorImpl::•("Field 'property6' has not been initialized.");
+  set property6(core::int? #t10) → void
+    if(this.{self::B1::_#B1#property6#isSet})
+      throw new _in::LateInitializationErrorImpl::•("Field 'property6' has already been initialized.");
+    else {
+      this.{self::B1::_#B1#property6#isSet} = true;
+      this.{self::B1::_#B1#property6} = #t10;
+    }
+}
+abstract class B2 extends core::Object implements self::B1 {
+  synthetic constructor •() → self::B2
+    : super core::Object::•()
+    ;
+  abstract set property4(core::int i) → void;
+  abstract set property5(core::int? i) → void;
+  abstract set property6(core::int i) → void;
+}
+abstract class C1 extends core::Object {
+  field core::int? _#C1#property4 = null;
+  field core::bool _#C1#property4#isSet = false;
+  field core::int? _#C1#property5 = null;
+  field core::bool _#C1#property5#isSet = false;
+  field core::int? _#C1#property6 = null;
+  field core::bool _#C1#property6#isSet = false;
+  constructor •(core::int property4, core::int property5, core::int property6) → self::C1
+    : self::C1::_#C1#property4#isSet = true, self::C1::_#C1#property4 = property4, self::C1::_#C1#property5#isSet = true, self::C1::_#C1#property5 = property5, self::C1::_#C1#property6#isSet = true, self::C1::_#C1#property6 = property6, super core::Object::•()
+    ;
+  get property4() → core::int
+    return this.{self::C1::_#C1#property4#isSet} ?{core::int} let final core::int? #t11 = this.{self::C1::_#C1#property4} in #t11{core::int} : throw new _in::LateInitializationErrorImpl::•("Field 'property4' has not been initialized.");
+  set property4(core::int #t12) → void {
+    this.{self::C1::_#C1#property4#isSet} = true;
+    this.{self::C1::_#C1#property4} = #t12;
+  }
+  get property5() → core::int
+    return this.{self::C1::_#C1#property5#isSet} ?{core::int} let final core::int? #t13 = this.{self::C1::_#C1#property5} in #t13{core::int} : throw new _in::LateInitializationErrorImpl::•("Field 'property5' has not been initialized.");
+  set property5(core::int #t14) → void {
+    this.{self::C1::_#C1#property5#isSet} = true;
+    this.{self::C1::_#C1#property5} = #t14;
+  }
+  get property6() → core::int
+    return this.{self::C1::_#C1#property6#isSet} ?{core::int} let final core::int? #t15 = this.{self::C1::_#C1#property6} in #t15{core::int} : throw new _in::LateInitializationErrorImpl::•("Field 'property6' has not been initialized.");
+  set property6(core::int #t16) → void {
+    this.{self::C1::_#C1#property6#isSet} = true;
+    this.{self::C1::_#C1#property6} = #t16;
+  }
+}
+abstract class C2 extends core::Object implements self::C1 {
+  synthetic constructor •() → self::C2
+    : super core::Object::•()
+    ;
+  abstract get property4() → core::int;
+  abstract get property5() → core::int;
+  abstract get property6() → core::int?;
+}
+static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart b/pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart
new file mode 100644
index 0000000..aaba82c
--- /dev/null
+++ b/pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart
@@ -0,0 +1,102 @@
+// 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.
+
+abstract class A {
+  int get property1; // ok
+  void set property1(int i);
+
+  int get property2; // ok
+  void set property2(int i);
+
+  num get property3; // error
+  void set property3(int i);
+
+  int property4 = 0; // ok
+
+  int property5 = 0; // ok
+
+  covariant num property6 = 0; // ok
+}
+
+abstract class B1 {
+  int get property1;
+
+  int get property2;
+
+  num get property3;
+
+  final int property4;
+
+  final int property5;
+
+  final num property6;
+
+  B1(this.property4, this.property5, this.property6);
+}
+
+abstract class B2 implements B1 {
+  void set property1(int i); // ok
+
+  void set property2(num i); // ok
+
+  void set property3(int i); // error
+
+  void set property4(int i); // ok
+
+  void set property5(num i); // ok
+
+  void set property6(int i); // error
+}
+
+abstract class C1 {
+  void set property1(int i);
+
+  void set property2(num i);
+
+  void set property3(int i);
+
+  int property4 = 0;
+
+  num property5 = 0;
+
+  int property6 = 0;
+}
+
+abstract class C2 implements C1 {
+  int get property1; // ok
+
+  int get property2; // ok
+
+  num get property3; // error
+
+  int get property4; // ok
+
+  int get property5; // ok
+
+  // This results in two errors; one for the getter/setter type mismatch and one
+  // for the getter override.
+  num get property6; // error
+}
+
+abstract class D1 {
+  int get property1;
+
+  int get property2;
+
+  num get property3;
+}
+
+abstract class D2 {
+  void set property1(int i);
+
+  void set property2(num i);
+
+  void set property3(int i);
+}
+
+abstract class D3 implements D1, D2 /* error on property3 */ {}
+
+abstract class D4 implements D3 /* no need for error on property3 */ {}
+
+main() {}
diff --git a/pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart.outline.expect b/pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart.outline.expect
new file mode 100644
index 0000000..e7d6448
--- /dev/null
+++ b/pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart.outline.expect
@@ -0,0 +1,147 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:12:11: Error: The type 'num' of the getter 'A.property3' is not a subtype of the type 'int' of the setter 'A.property3'.
+//   num get property3; // error
+//           ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:13:12: Context: This is the declaration of the setter 'A.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:43:12: Error: The type 'num' of the inherited getter 'B1.property3' is not a subtype of the type 'int' of the setter 'B2.property3'.
+//   void set property3(int i); // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:27:11: Context: This is the declaration of the getter 'B1.property3'.
+//   num get property3;
+//           ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:49:12: Error: The type 'num' of the inherited field 'B1.property6' is not a subtype of the type 'int' of the setter 'B2.property6'.
+//   void set property6(int i); // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:33:13: Context: This is the declaration of the field 'B1.property6'.
+//   final num property6;
+//             ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:71:11: Error: The type 'num' of the getter 'C2.property3' is not a subtype of the type 'int' of the inherited setter 'C1.property3'.
+//   num get property3; // error
+//           ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:57:12: Context: This is the declaration of the setter 'C1.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:79:11: Error: The return type of the method 'C2.property6' is 'num', which does not match the return type, 'int', of the overridden method, 'C1.property6'.
+// Change to a subtype of 'int'.
+//   num get property6; // error
+//           ^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:63:7: Context: This is the overridden method ('property6').
+//   int property6 = 0;
+//       ^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:79:11: Error: The type 'num' of the getter 'C2.property6' is not a subtype of the type 'int' of the inherited setter 'C1.property6'.
+//   num get property6; // error
+//           ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:63:7: Context: This is the declaration of the setter 'C1.property6'.
+//   int property6 = 0;
+//       ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:98:16: Error: The type 'num' of the inherited getter 'D1.property3' is not a subtype of the type 'int' of the inherited setter 'D2.property3'.
+// abstract class D3 implements D1, D2 /* error on property3 */ {}
+//                ^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:87:11: Context: This is the declaration of the getter 'D1.property3'.
+//   num get property3;
+//           ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:95:12: Context: This is the declaration of the setter 'D2.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:100:16: Error: The type 'num' of the inherited getter 'D1.property3' is not a subtype of the type 'int' of the inherited setter 'D2.property3'.
+// abstract class D4 implements D3 /* no need for error on property3 */ {}
+//                ^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:87:11: Context: This is the declaration of the getter 'D1.property3'.
+//   num get property3;
+//           ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:95:12: Context: This is the declaration of the setter 'D2.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+import self as self;
+import "dart:core" as core;
+
+abstract class A extends core::Object {
+  field core::int property4;
+  field core::int property5;
+  covariant field core::num property6;
+  synthetic constructor •() → self::A
+    ;
+  abstract get property1() → core::int;
+  abstract set property1(core::int i) → void;
+  abstract get property2() → core::int;
+  abstract set property2(core::int i) → void;
+  abstract get property3() → core::num;
+  abstract set property3(core::int i) → void;
+}
+abstract class B1 extends core::Object {
+  final field core::int property4;
+  final field core::int property5;
+  final field core::num property6;
+  constructor •(core::int property4, core::int property5, core::num property6) → self::B1
+    ;
+  abstract get property1() → core::int;
+  abstract get property2() → core::int;
+  abstract get property3() → core::num;
+}
+abstract class B2 extends core::Object implements self::B1 {
+  synthetic constructor •() → self::B2
+    ;
+  abstract set property1(core::int i) → void;
+  abstract set property2(core::num i) → void;
+  abstract set property3(core::int i) → void;
+  abstract set property4(core::int i) → void;
+  abstract set property5(core::num i) → void;
+  abstract set property6(core::int i) → void;
+}
+abstract class C1 extends core::Object {
+  field core::int property4;
+  field core::num property5;
+  field core::int property6;
+  synthetic constructor •() → self::C1
+    ;
+  abstract set property1(core::int i) → void;
+  abstract set property2(core::num i) → void;
+  abstract set property3(core::int i) → void;
+}
+abstract class C2 extends core::Object implements self::C1 {
+  synthetic constructor •() → self::C2
+    ;
+  abstract get property1() → core::int;
+  abstract get property2() → core::int;
+  abstract get property3() → core::num;
+  abstract get property4() → core::int;
+  abstract get property5() → core::int;
+  abstract get property6() → core::num;
+}
+abstract class D1 extends core::Object {
+  synthetic constructor •() → self::D1
+    ;
+  abstract get property1() → core::int;
+  abstract get property2() → core::int;
+  abstract get property3() → core::num;
+}
+abstract class D2 extends core::Object {
+  synthetic constructor •() → self::D2
+    ;
+  abstract set property1(core::int i) → void;
+  abstract set property2(core::num i) → void;
+  abstract set property3(core::int i) → void;
+}
+abstract class D3 extends core::Object implements self::D1, self::D2 {
+  synthetic constructor •() → self::D3
+    ;
+}
+abstract class D4 extends core::Object implements self::D3 {
+  synthetic constructor •() → self::D4
+    ;
+}
+static method main() → dynamic
+  ;
diff --git a/pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart.strong.expect b/pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart.strong.expect
new file mode 100644
index 0000000..5c5052b
--- /dev/null
+++ b/pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart.strong.expect
@@ -0,0 +1,155 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:12:11: Error: The type 'num' of the getter 'A.property3' is not a subtype of the type 'int' of the setter 'A.property3'.
+//   num get property3; // error
+//           ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:13:12: Context: This is the declaration of the setter 'A.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:43:12: Error: The type 'num' of the inherited getter 'B1.property3' is not a subtype of the type 'int' of the setter 'B2.property3'.
+//   void set property3(int i); // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:27:11: Context: This is the declaration of the getter 'B1.property3'.
+//   num get property3;
+//           ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:49:12: Error: The type 'num' of the inherited field 'B1.property6' is not a subtype of the type 'int' of the setter 'B2.property6'.
+//   void set property6(int i); // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:33:13: Context: This is the declaration of the field 'B1.property6'.
+//   final num property6;
+//             ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:71:11: Error: The type 'num' of the getter 'C2.property3' is not a subtype of the type 'int' of the inherited setter 'C1.property3'.
+//   num get property3; // error
+//           ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:57:12: Context: This is the declaration of the setter 'C1.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:79:11: Error: The return type of the method 'C2.property6' is 'num', which does not match the return type, 'int', of the overridden method, 'C1.property6'.
+// Change to a subtype of 'int'.
+//   num get property6; // error
+//           ^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:63:7: Context: This is the overridden method ('property6').
+//   int property6 = 0;
+//       ^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:79:11: Error: The type 'num' of the getter 'C2.property6' is not a subtype of the type 'int' of the inherited setter 'C1.property6'.
+//   num get property6; // error
+//           ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:63:7: Context: This is the declaration of the setter 'C1.property6'.
+//   int property6 = 0;
+//       ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:98:16: Error: The type 'num' of the inherited getter 'D1.property3' is not a subtype of the type 'int' of the inherited setter 'D2.property3'.
+// abstract class D3 implements D1, D2 /* error on property3 */ {}
+//                ^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:87:11: Context: This is the declaration of the getter 'D1.property3'.
+//   num get property3;
+//           ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:95:12: Context: This is the declaration of the setter 'D2.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:100:16: Error: The type 'num' of the inherited getter 'D1.property3' is not a subtype of the type 'int' of the inherited setter 'D2.property3'.
+// abstract class D4 implements D3 /* no need for error on property3 */ {}
+//                ^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:87:11: Context: This is the declaration of the getter 'D1.property3'.
+//   num get property3;
+//           ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:95:12: Context: This is the declaration of the setter 'D2.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+import self as self;
+import "dart:core" as core;
+
+abstract class A extends core::Object {
+  field core::int property4 = 0;
+  field core::int property5 = 0;
+  covariant field core::num property6 = 0;
+  synthetic constructor •() → self::A
+    : super core::Object::•()
+    ;
+  abstract get property1() → core::int;
+  abstract set property1(core::int i) → void;
+  abstract get property2() → core::int;
+  abstract set property2(core::int i) → void;
+  abstract get property3() → core::num;
+  abstract set property3(core::int i) → void;
+}
+abstract class B1 extends core::Object {
+  final field core::int property4;
+  final field core::int property5;
+  final field core::num property6;
+  constructor •(core::int property4, core::int property5, core::num property6) → self::B1
+    : self::B1::property4 = property4, self::B1::property5 = property5, self::B1::property6 = property6, super core::Object::•()
+    ;
+  abstract get property1() → core::int;
+  abstract get property2() → core::int;
+  abstract get property3() → core::num;
+}
+abstract class B2 extends core::Object implements self::B1 {
+  synthetic constructor •() → self::B2
+    : super core::Object::•()
+    ;
+  abstract set property1(core::int i) → void;
+  abstract set property2(core::num i) → void;
+  abstract set property3(core::int i) → void;
+  abstract set property4(core::int i) → void;
+  abstract set property5(core::num i) → void;
+  abstract set property6(core::int i) → void;
+}
+abstract class C1 extends core::Object {
+  field core::int property4 = 0;
+  field core::num property5 = 0;
+  field core::int property6 = 0;
+  synthetic constructor •() → self::C1
+    : super core::Object::•()
+    ;
+  abstract set property1(core::int i) → void;
+  abstract set property2(core::num i) → void;
+  abstract set property3(core::int i) → void;
+}
+abstract class C2 extends core::Object implements self::C1 {
+  synthetic constructor •() → self::C2
+    : super core::Object::•()
+    ;
+  abstract get property1() → core::int;
+  abstract get property2() → core::int;
+  abstract get property3() → core::num;
+  abstract get property4() → core::int;
+  abstract get property5() → core::int;
+  abstract get property6() → core::num;
+}
+abstract class D1 extends core::Object {
+  synthetic constructor •() → self::D1
+    : super core::Object::•()
+    ;
+  abstract get property1() → core::int;
+  abstract get property2() → core::int;
+  abstract get property3() → core::num;
+}
+abstract class D2 extends core::Object {
+  synthetic constructor •() → self::D2
+    : super core::Object::•()
+    ;
+  abstract set property1(core::int i) → void;
+  abstract set property2(core::num i) → void;
+  abstract set property3(core::int i) → void;
+}
+abstract class D3 extends core::Object implements self::D1, self::D2 {
+  synthetic constructor •() → self::D3
+    : super core::Object::•()
+    ;
+}
+abstract class D4 extends core::Object implements self::D3 {
+  synthetic constructor •() → self::D4
+    : super core::Object::•()
+    ;
+}
+static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart.strong.transformed.expect b/pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart.strong.transformed.expect
new file mode 100644
index 0000000..4e6abc1
--- /dev/null
+++ b/pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart.strong.transformed.expect
@@ -0,0 +1,155 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:14:12: Error: The type 'int?' of the getter 'A.property3' is not a subtype of the type 'int' of the setter 'A.property3'.
+//   int? get property3; // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:16:12: Context: This is the declaration of the setter 'A.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:48:12: Error: The type 'int?' of the inherited getter 'B1.property3' is not a subtype of the type 'int' of the setter 'B2.property3'.
+//   void set property3(int i); // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:32:12: Context: This is the declaration of the getter 'B1.property3'.
+//   int? get property3;
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:54:12: Error: The type 'int?' of the inherited field 'B1.property6' is not a subtype of the type 'int' of the setter 'B2.property6'.
+//   void set property6(int i); // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:38:14: Context: This is the declaration of the field 'B1.property6'.
+//   final int? property6;
+//              ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:78:12: Error: The type 'int?' of the getter 'C2.property3' is not a subtype of the type 'int' of the inherited setter 'C1.property3'.
+//   int? get property3; // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:62:12: Context: This is the declaration of the setter 'C1.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:86:12: Error: The return type of the method 'C2.property6' is 'int?', which does not match the return type, 'int', of the overridden method, 'C1.property6'.
+// Change to a subtype of 'int'.
+//   int? get property6; // error
+//            ^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:68:7: Context: This is the overridden method ('property6').
+//   int property6;
+//       ^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:86:12: Error: The type 'int?' of the getter 'C2.property6' is not a subtype of the type 'int' of the inherited setter 'C1.property6'.
+//   int? get property6; // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:68:7: Context: This is the declaration of the setter 'C1.property6'.
+//   int property6;
+//       ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:105:16: Error: The type 'int?' of the inherited getter 'D1.property3' is not a subtype of the type 'int' of the inherited setter 'D2.property3'.
+// abstract class D3 implements D1, D2 /* error on property3 */ {}
+//                ^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:94:12: Context: This is the declaration of the getter 'D1.property3'.
+//   int? get property3;
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:102:12: Context: This is the declaration of the setter 'D2.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:107:16: Error: The type 'int?' of the inherited getter 'D1.property3' is not a subtype of the type 'int' of the inherited setter 'D2.property3'.
+// abstract class D4 implements D3 /* no need for error on property3 */ {}
+//                ^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:94:12: Context: This is the declaration of the getter 'D1.property3'.
+//   int? get property3;
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:102:12: Context: This is the declaration of the setter 'D2.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+import self as self;
+import "dart:core" as core;
+
+abstract class A extends core::Object {
+  field core::int property4;
+  field core::int? property5;
+  covariant field core::int property6;
+  constructor •(core::int property4, core::int? property5, core::int property6) → self::A
+    : self::A::property4 = property4, self::A::property5 = property5, self::A::property6 = property6, super core::Object::•()
+    ;
+  abstract get property1() → core::int;
+  abstract set property1(core::int i) → void;
+  abstract get property2() → core::int;
+  abstract set property2(core::int? i) → void;
+  abstract get property3() → core::int?;
+  abstract set property3(core::int i) → void;
+}
+abstract class B1 extends core::Object {
+  final field core::int property4;
+  final field core::int property5;
+  final field core::int? property6;
+  constructor •(core::int property4, core::int property5, core::int? property6) → self::B1
+    : self::B1::property4 = property4, self::B1::property5 = property5, self::B1::property6 = property6, super core::Object::•()
+    ;
+  abstract get property1() → core::int;
+  abstract get property2() → core::int;
+  abstract get property3() → core::int?;
+}
+abstract class B2 extends core::Object implements self::B1 {
+  synthetic constructor •() → self::B2
+    : super core::Object::•()
+    ;
+  abstract set property1(core::int i) → void;
+  abstract set property2(core::int? i) → void;
+  abstract set property3(core::int i) → void;
+  abstract set property4(core::int i) → void;
+  abstract set property5(core::int? i) → void;
+  abstract set property6(core::int i) → void;
+}
+abstract class C1 extends core::Object {
+  field core::int property4;
+  field core::int? property5;
+  field core::int property6;
+  constructor •(core::int property4, core::int? property5, core::int property6) → self::C1
+    : self::C1::property4 = property4, self::C1::property5 = property5, self::C1::property6 = property6, super core::Object::•()
+    ;
+  abstract set property1(core::int i) → void;
+  abstract set property2(core::int? i) → void;
+  abstract set property3(core::int i) → void;
+}
+abstract class C2 extends core::Object implements self::C1 {
+  synthetic constructor •() → self::C2
+    : super core::Object::•()
+    ;
+  abstract get property1() → core::int;
+  abstract get property2() → core::int;
+  abstract get property3() → core::int?;
+  abstract get property4() → core::int;
+  abstract get property5() → core::int;
+  abstract get property6() → core::int?;
+}
+abstract class D1 extends core::Object {
+  synthetic constructor •() → self::D1
+    : super core::Object::•()
+    ;
+  abstract get property1() → core::int;
+  abstract get property2() → core::int;
+  abstract get property3() → core::int?;
+}
+abstract class D2 extends core::Object {
+  synthetic constructor •() → self::D2
+    : super core::Object::•()
+    ;
+  abstract set property1(core::int i) → void;
+  abstract set property2(core::int? i) → void;
+  abstract set property3(core::int i) → void;
+}
+abstract class D3 extends core::Object implements self::D1, self::D2 {
+  synthetic constructor •() → self::D3
+    : super core::Object::•()
+    ;
+}
+abstract class D4 extends core::Object implements self::D3 {
+  synthetic constructor •() → self::D4
+    : super core::Object::•()
+    ;
+}
+static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart.textual_outline.expect b/pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart.textual_outline.expect
new file mode 100644
index 0000000..bc0af57
--- /dev/null
+++ b/pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart.textual_outline.expect
@@ -0,0 +1,66 @@
+abstract class A {
+  int get property1;
+  void set property1(int i);
+  int get property2;
+  void set property2(int i);
+  num get property3;
+  void set property3(int i);
+  int property4 = 0;
+  int property5 = 0;
+  covariant num property6 = 0;
+}
+
+abstract class B1 {
+  int get property1;
+  int get property2;
+  num get property3;
+  final int property4;
+  final int property5;
+  final num property6;
+  B1(this.property4, this.property5, this.property6);
+}
+
+abstract class B2 implements B1 {
+  void set property1(int i);
+  void set property2(num i);
+  void set property3(int i);
+  void set property4(int i);
+  void set property5(num i);
+  void set property6(int i);
+}
+
+abstract class C1 {
+  void set property1(int i);
+  void set property2(num i);
+  void set property3(int i);
+  int property4 = 0;
+  num property5 = 0;
+  int property6 = 0;
+}
+
+abstract class C2 implements C1 {
+  int get property1;
+  int get property2;
+  num get property3;
+  int get property4;
+  int get property5;
+  num get property6;
+}
+
+abstract class D1 {
+  int get property1;
+  int get property2;
+  num get property3;
+}
+
+abstract class D2 {
+  void set property1(int i);
+  void set property2(num i);
+  void set property3(int i);
+}
+
+abstract class D3 implements D1, D2 {}
+
+abstract class D4 implements D3 {}
+
+main() {}
diff --git a/pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart.textual_outline_modelled.expect b/pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart.textual_outline_modelled.expect
new file mode 100644
index 0000000..43c1a56
--- /dev/null
+++ b/pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart.textual_outline_modelled.expect
@@ -0,0 +1,66 @@
+abstract class A {
+  covariant num property6 = 0;
+  int get property1;
+  int get property2;
+  int property4 = 0;
+  int property5 = 0;
+  num get property3;
+  void set property1(int i);
+  void set property2(int i);
+  void set property3(int i);
+}
+
+abstract class B1 {
+  B1(this.property4, this.property5, this.property6);
+  final int property4;
+  final int property5;
+  final num property6;
+  int get property1;
+  int get property2;
+  num get property3;
+}
+
+abstract class B2 implements B1 {
+  void set property1(int i);
+  void set property2(num i);
+  void set property3(int i);
+  void set property4(int i);
+  void set property5(num i);
+  void set property6(int i);
+}
+
+abstract class C1 {
+  int property4 = 0;
+  int property6 = 0;
+  num property5 = 0;
+  void set property1(int i);
+  void set property2(num i);
+  void set property3(int i);
+}
+
+abstract class C2 implements C1 {
+  int get property1;
+  int get property2;
+  int get property4;
+  int get property5;
+  num get property3;
+  num get property6;
+}
+
+abstract class D1 {
+  int get property1;
+  int get property2;
+  num get property3;
+}
+
+abstract class D2 {
+  void set property1(int i);
+  void set property2(num i);
+  void set property3(int i);
+}
+
+abstract class D3 implements D1, D2 {}
+
+abstract class D4 implements D3 {}
+
+main() {}
diff --git a/pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart.weak.expect b/pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart.weak.expect
new file mode 100644
index 0000000..5c5052b
--- /dev/null
+++ b/pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart.weak.expect
@@ -0,0 +1,155 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:12:11: Error: The type 'num' of the getter 'A.property3' is not a subtype of the type 'int' of the setter 'A.property3'.
+//   num get property3; // error
+//           ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:13:12: Context: This is the declaration of the setter 'A.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:43:12: Error: The type 'num' of the inherited getter 'B1.property3' is not a subtype of the type 'int' of the setter 'B2.property3'.
+//   void set property3(int i); // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:27:11: Context: This is the declaration of the getter 'B1.property3'.
+//   num get property3;
+//           ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:49:12: Error: The type 'num' of the inherited field 'B1.property6' is not a subtype of the type 'int' of the setter 'B2.property6'.
+//   void set property6(int i); // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:33:13: Context: This is the declaration of the field 'B1.property6'.
+//   final num property6;
+//             ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:71:11: Error: The type 'num' of the getter 'C2.property3' is not a subtype of the type 'int' of the inherited setter 'C1.property3'.
+//   num get property3; // error
+//           ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:57:12: Context: This is the declaration of the setter 'C1.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:79:11: Error: The return type of the method 'C2.property6' is 'num', which does not match the return type, 'int', of the overridden method, 'C1.property6'.
+// Change to a subtype of 'int'.
+//   num get property6; // error
+//           ^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:63:7: Context: This is the overridden method ('property6').
+//   int property6 = 0;
+//       ^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:79:11: Error: The type 'num' of the getter 'C2.property6' is not a subtype of the type 'int' of the inherited setter 'C1.property6'.
+//   num get property6; // error
+//           ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:63:7: Context: This is the declaration of the setter 'C1.property6'.
+//   int property6 = 0;
+//       ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:98:16: Error: The type 'num' of the inherited getter 'D1.property3' is not a subtype of the type 'int' of the inherited setter 'D2.property3'.
+// abstract class D3 implements D1, D2 /* error on property3 */ {}
+//                ^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:87:11: Context: This is the declaration of the getter 'D1.property3'.
+//   num get property3;
+//           ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:95:12: Context: This is the declaration of the setter 'D2.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:100:16: Error: The type 'num' of the inherited getter 'D1.property3' is not a subtype of the type 'int' of the inherited setter 'D2.property3'.
+// abstract class D4 implements D3 /* no need for error on property3 */ {}
+//                ^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:87:11: Context: This is the declaration of the getter 'D1.property3'.
+//   num get property3;
+//           ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:95:12: Context: This is the declaration of the setter 'D2.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+import self as self;
+import "dart:core" as core;
+
+abstract class A extends core::Object {
+  field core::int property4 = 0;
+  field core::int property5 = 0;
+  covariant field core::num property6 = 0;
+  synthetic constructor •() → self::A
+    : super core::Object::•()
+    ;
+  abstract get property1() → core::int;
+  abstract set property1(core::int i) → void;
+  abstract get property2() → core::int;
+  abstract set property2(core::int i) → void;
+  abstract get property3() → core::num;
+  abstract set property3(core::int i) → void;
+}
+abstract class B1 extends core::Object {
+  final field core::int property4;
+  final field core::int property5;
+  final field core::num property6;
+  constructor •(core::int property4, core::int property5, core::num property6) → self::B1
+    : self::B1::property4 = property4, self::B1::property5 = property5, self::B1::property6 = property6, super core::Object::•()
+    ;
+  abstract get property1() → core::int;
+  abstract get property2() → core::int;
+  abstract get property3() → core::num;
+}
+abstract class B2 extends core::Object implements self::B1 {
+  synthetic constructor •() → self::B2
+    : super core::Object::•()
+    ;
+  abstract set property1(core::int i) → void;
+  abstract set property2(core::num i) → void;
+  abstract set property3(core::int i) → void;
+  abstract set property4(core::int i) → void;
+  abstract set property5(core::num i) → void;
+  abstract set property6(core::int i) → void;
+}
+abstract class C1 extends core::Object {
+  field core::int property4 = 0;
+  field core::num property5 = 0;
+  field core::int property6 = 0;
+  synthetic constructor •() → self::C1
+    : super core::Object::•()
+    ;
+  abstract set property1(core::int i) → void;
+  abstract set property2(core::num i) → void;
+  abstract set property3(core::int i) → void;
+}
+abstract class C2 extends core::Object implements self::C1 {
+  synthetic constructor •() → self::C2
+    : super core::Object::•()
+    ;
+  abstract get property1() → core::int;
+  abstract get property2() → core::int;
+  abstract get property3() → core::num;
+  abstract get property4() → core::int;
+  abstract get property5() → core::int;
+  abstract get property6() → core::num;
+}
+abstract class D1 extends core::Object {
+  synthetic constructor •() → self::D1
+    : super core::Object::•()
+    ;
+  abstract get property1() → core::int;
+  abstract get property2() → core::int;
+  abstract get property3() → core::num;
+}
+abstract class D2 extends core::Object {
+  synthetic constructor •() → self::D2
+    : super core::Object::•()
+    ;
+  abstract set property1(core::int i) → void;
+  abstract set property2(core::num i) → void;
+  abstract set property3(core::int i) → void;
+}
+abstract class D3 extends core::Object implements self::D1, self::D2 {
+  synthetic constructor •() → self::D3
+    : super core::Object::•()
+    ;
+}
+abstract class D4 extends core::Object implements self::D3 {
+  synthetic constructor •() → self::D4
+    : super core::Object::•()
+    ;
+}
+static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart.weak.transformed.expect b/pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart.weak.transformed.expect
new file mode 100644
index 0000000..4e6abc1
--- /dev/null
+++ b/pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart.weak.transformed.expect
@@ -0,0 +1,155 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:14:12: Error: The type 'int?' of the getter 'A.property3' is not a subtype of the type 'int' of the setter 'A.property3'.
+//   int? get property3; // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:16:12: Context: This is the declaration of the setter 'A.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:48:12: Error: The type 'int?' of the inherited getter 'B1.property3' is not a subtype of the type 'int' of the setter 'B2.property3'.
+//   void set property3(int i); // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:32:12: Context: This is the declaration of the getter 'B1.property3'.
+//   int? get property3;
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:54:12: Error: The type 'int?' of the inherited field 'B1.property6' is not a subtype of the type 'int' of the setter 'B2.property6'.
+//   void set property6(int i); // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:38:14: Context: This is the declaration of the field 'B1.property6'.
+//   final int? property6;
+//              ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:78:12: Error: The type 'int?' of the getter 'C2.property3' is not a subtype of the type 'int' of the inherited setter 'C1.property3'.
+//   int? get property3; // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:62:12: Context: This is the declaration of the setter 'C1.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:86:12: Error: The return type of the method 'C2.property6' is 'int?', which does not match the return type, 'int', of the overridden method, 'C1.property6'.
+// Change to a subtype of 'int'.
+//   int? get property6; // error
+//            ^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:68:7: Context: This is the overridden method ('property6').
+//   int property6;
+//       ^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:86:12: Error: The type 'int?' of the getter 'C2.property6' is not a subtype of the type 'int' of the inherited setter 'C1.property6'.
+//   int? get property6; // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:68:7: Context: This is the declaration of the setter 'C1.property6'.
+//   int property6;
+//       ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:105:16: Error: The type 'int?' of the inherited getter 'D1.property3' is not a subtype of the type 'int' of the inherited setter 'D2.property3'.
+// abstract class D3 implements D1, D2 /* error on property3 */ {}
+//                ^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:94:12: Context: This is the declaration of the getter 'D1.property3'.
+//   int? get property3;
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:102:12: Context: This is the declaration of the setter 'D2.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:107:16: Error: The type 'int?' of the inherited getter 'D1.property3' is not a subtype of the type 'int' of the inherited setter 'D2.property3'.
+// abstract class D4 implements D3 /* no need for error on property3 */ {}
+//                ^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:94:12: Context: This is the declaration of the getter 'D1.property3'.
+//   int? get property3;
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type.dart:102:12: Context: This is the declaration of the setter 'D2.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+import self as self;
+import "dart:core" as core;
+
+abstract class A extends core::Object {
+  field core::int property4;
+  field core::int? property5;
+  covariant field core::int property6;
+  constructor •(core::int property4, core::int? property5, core::int property6) → self::A
+    : self::A::property4 = property4, self::A::property5 = property5, self::A::property6 = property6, super core::Object::•()
+    ;
+  abstract get property1() → core::int;
+  abstract set property1(core::int i) → void;
+  abstract get property2() → core::int;
+  abstract set property2(core::int? i) → void;
+  abstract get property3() → core::int?;
+  abstract set property3(core::int i) → void;
+}
+abstract class B1 extends core::Object {
+  final field core::int property4;
+  final field core::int property5;
+  final field core::int? property6;
+  constructor •(core::int property4, core::int property5, core::int? property6) → self::B1
+    : self::B1::property4 = property4, self::B1::property5 = property5, self::B1::property6 = property6, super core::Object::•()
+    ;
+  abstract get property1() → core::int;
+  abstract get property2() → core::int;
+  abstract get property3() → core::int?;
+}
+abstract class B2 extends core::Object implements self::B1 {
+  synthetic constructor •() → self::B2
+    : super core::Object::•()
+    ;
+  abstract set property1(core::int i) → void;
+  abstract set property2(core::int? i) → void;
+  abstract set property3(core::int i) → void;
+  abstract set property4(core::int i) → void;
+  abstract set property5(core::int? i) → void;
+  abstract set property6(core::int i) → void;
+}
+abstract class C1 extends core::Object {
+  field core::int property4;
+  field core::int? property5;
+  field core::int property6;
+  constructor •(core::int property4, core::int? property5, core::int property6) → self::C1
+    : self::C1::property4 = property4, self::C1::property5 = property5, self::C1::property6 = property6, super core::Object::•()
+    ;
+  abstract set property1(core::int i) → void;
+  abstract set property2(core::int? i) → void;
+  abstract set property3(core::int i) → void;
+}
+abstract class C2 extends core::Object implements self::C1 {
+  synthetic constructor •() → self::C2
+    : super core::Object::•()
+    ;
+  abstract get property1() → core::int;
+  abstract get property2() → core::int;
+  abstract get property3() → core::int?;
+  abstract get property4() → core::int;
+  abstract get property5() → core::int;
+  abstract get property6() → core::int?;
+}
+abstract class D1 extends core::Object {
+  synthetic constructor •() → self::D1
+    : super core::Object::•()
+    ;
+  abstract get property1() → core::int;
+  abstract get property2() → core::int;
+  abstract get property3() → core::int?;
+}
+abstract class D2 extends core::Object {
+  synthetic constructor •() → self::D2
+    : super core::Object::•()
+    ;
+  abstract set property1(core::int i) → void;
+  abstract set property2(core::int? i) → void;
+  abstract set property3(core::int i) → void;
+}
+abstract class D3 extends core::Object implements self::D1, self::D2 {
+  synthetic constructor •() → self::D3
+    : super core::Object::•()
+    ;
+}
+abstract class D4 extends core::Object implements self::D3 {
+  synthetic constructor •() → self::D4
+    : super core::Object::•()
+    ;
+}
+static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart b/pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart
new file mode 100644
index 0000000..ca3246a
--- /dev/null
+++ b/pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart
@@ -0,0 +1,53 @@
+// 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.
+
+abstract class A {
+  late int property4; // ok
+
+  late int? property5; // ok
+
+  covariant late int property6; // ok
+
+  A(this.property4, this.property5, this.property6);
+}
+
+abstract class B1 {
+  late final int property4;
+
+  late final int property5;
+
+  late final int? property6;
+
+  B1(this.property4, this.property5, this.property6);
+}
+
+abstract class B2 implements B1 {
+  void set property4(int i); // ok
+
+  void set property5(int? i); // ok
+
+  void set property6(int i); // error
+}
+
+abstract class C1 {
+  late int property4;
+
+  late int property5;
+
+  late int property6;
+
+  C1(this.property4, this.property5, this.property6);
+}
+
+abstract class C2 implements C1 {
+  int get property4; // ok
+
+  int get property5; // ok
+
+  // This results in two errors; one for the getter/setter type mismatch and one
+  // for the getter override.
+  int? get property6; // error
+}
+
+main() {}
diff --git a/pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart.outline.expect b/pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart.outline.expect
new file mode 100644
index 0000000..36042d2
--- /dev/null
+++ b/pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart.outline.expect
@@ -0,0 +1,66 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart:30:12: Error: The type 'int?' of the inherited field 'B1.property6' is not a subtype of the type 'int' of the setter 'B2.property6'.
+//   void set property6(int i); // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart:20:19: Context: This is the declaration of the field 'B1.property6'.
+//   late final int? property6;
+//                   ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart:50:12: Error: The return type of the method 'C2.property6' is 'int?', which does not match the return type, 'int', of the overridden method, 'C1.property6'.
+// Change to a subtype of 'int'.
+//   int? get property6; // error
+//            ^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart:38:12: Context: This is the overridden method ('property6').
+//   late int property6;
+//            ^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart:50:12: Error: The type 'int?' of the getter 'C2.property6' is not a subtype of the type 'int' of the inherited setter 'C1.property6'.
+//   int? get property6; // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart:38:12: Context: This is the declaration of the setter 'C1.property6'.
+//   late int property6;
+//            ^^^^^^^^^
+//
+import self as self;
+import "dart:core" as core;
+
+abstract class A extends core::Object {
+  late field core::int property4;
+  late field core::int? property5;
+  late covariant field core::int property6;
+  constructor •(core::int property4, core::int? property5, core::int property6) → self::A
+    ;
+}
+abstract class B1 extends core::Object {
+  late final [setter] field core::int property4;
+  late final [setter] field core::int property5;
+  late final [setter] field core::int? property6;
+  constructor •(core::int property4, core::int property5, core::int? property6) → self::B1
+    ;
+}
+abstract class B2 extends core::Object implements self::B1 {
+  synthetic constructor •() → self::B2
+    ;
+  abstract set property4(core::int i) → void;
+  abstract set property5(core::int? i) → void;
+  abstract set property6(core::int i) → void;
+}
+abstract class C1 extends core::Object {
+  late field core::int property4;
+  late field core::int property5;
+  late field core::int property6;
+  constructor •(core::int property4, core::int property5, core::int property6) → self::C1
+    ;
+}
+abstract class C2 extends core::Object implements self::C1 {
+  synthetic constructor •() → self::C2
+    ;
+  abstract get property4() → core::int;
+  abstract get property5() → core::int;
+  abstract get property6() → core::int?;
+}
+static method main() → dynamic
+  ;
diff --git a/pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart.strong.expect b/pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart.strong.expect
new file mode 100644
index 0000000..e53ccba4
--- /dev/null
+++ b/pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart.strong.expect
@@ -0,0 +1,70 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart:30:12: Error: The type 'int?' of the inherited field 'B1.property6' is not a subtype of the type 'int' of the setter 'B2.property6'.
+//   void set property6(int i); // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart:20:19: Context: This is the declaration of the field 'B1.property6'.
+//   late final int? property6;
+//                   ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart:50:12: Error: The return type of the method 'C2.property6' is 'int?', which does not match the return type, 'int', of the overridden method, 'C1.property6'.
+// Change to a subtype of 'int'.
+//   int? get property6; // error
+//            ^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart:38:12: Context: This is the overridden method ('property6').
+//   late int property6;
+//            ^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart:50:12: Error: The type 'int?' of the getter 'C2.property6' is not a subtype of the type 'int' of the inherited setter 'C1.property6'.
+//   int? get property6; // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart:38:12: Context: This is the declaration of the setter 'C1.property6'.
+//   late int property6;
+//            ^^^^^^^^^
+//
+import self as self;
+import "dart:core" as core;
+
+abstract class A extends core::Object {
+  late field core::int property4;
+  late field core::int? property5;
+  late covariant field core::int property6;
+  constructor •(core::int property4, core::int? property5, core::int property6) → self::A
+    : self::A::property4 = property4, self::A::property5 = property5, self::A::property6 = property6, super core::Object::•()
+    ;
+}
+abstract class B1 extends core::Object {
+  late final [setter] field core::int property4;
+  late final [setter] field core::int property5;
+  late final [setter] field core::int? property6;
+  constructor •(core::int property4, core::int property5, core::int? property6) → self::B1
+    : self::B1::property4 = property4, self::B1::property5 = property5, self::B1::property6 = property6, super core::Object::•()
+    ;
+}
+abstract class B2 extends core::Object implements self::B1 {
+  synthetic constructor •() → self::B2
+    : super core::Object::•()
+    ;
+  abstract set property4(core::int i) → void;
+  abstract set property5(core::int? i) → void;
+  abstract set property6(core::int i) → void;
+}
+abstract class C1 extends core::Object {
+  late field core::int property4;
+  late field core::int property5;
+  late field core::int property6;
+  constructor •(core::int property4, core::int property5, core::int property6) → self::C1
+    : self::C1::property4 = property4, self::C1::property5 = property5, self::C1::property6 = property6, super core::Object::•()
+    ;
+}
+abstract class C2 extends core::Object implements self::C1 {
+  synthetic constructor •() → self::C2
+    : super core::Object::•()
+    ;
+  abstract get property4() → core::int;
+  abstract get property5() → core::int;
+  abstract get property6() → core::int?;
+}
+static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart.strong.transformed.expect b/pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart.strong.transformed.expect
new file mode 100644
index 0000000..e53ccba4
--- /dev/null
+++ b/pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart.strong.transformed.expect
@@ -0,0 +1,70 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart:30:12: Error: The type 'int?' of the inherited field 'B1.property6' is not a subtype of the type 'int' of the setter 'B2.property6'.
+//   void set property6(int i); // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart:20:19: Context: This is the declaration of the field 'B1.property6'.
+//   late final int? property6;
+//                   ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart:50:12: Error: The return type of the method 'C2.property6' is 'int?', which does not match the return type, 'int', of the overridden method, 'C1.property6'.
+// Change to a subtype of 'int'.
+//   int? get property6; // error
+//            ^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart:38:12: Context: This is the overridden method ('property6').
+//   late int property6;
+//            ^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart:50:12: Error: The type 'int?' of the getter 'C2.property6' is not a subtype of the type 'int' of the inherited setter 'C1.property6'.
+//   int? get property6; // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart:38:12: Context: This is the declaration of the setter 'C1.property6'.
+//   late int property6;
+//            ^^^^^^^^^
+//
+import self as self;
+import "dart:core" as core;
+
+abstract class A extends core::Object {
+  late field core::int property4;
+  late field core::int? property5;
+  late covariant field core::int property6;
+  constructor •(core::int property4, core::int? property5, core::int property6) → self::A
+    : self::A::property4 = property4, self::A::property5 = property5, self::A::property6 = property6, super core::Object::•()
+    ;
+}
+abstract class B1 extends core::Object {
+  late final [setter] field core::int property4;
+  late final [setter] field core::int property5;
+  late final [setter] field core::int? property6;
+  constructor •(core::int property4, core::int property5, core::int? property6) → self::B1
+    : self::B1::property4 = property4, self::B1::property5 = property5, self::B1::property6 = property6, super core::Object::•()
+    ;
+}
+abstract class B2 extends core::Object implements self::B1 {
+  synthetic constructor •() → self::B2
+    : super core::Object::•()
+    ;
+  abstract set property4(core::int i) → void;
+  abstract set property5(core::int? i) → void;
+  abstract set property6(core::int i) → void;
+}
+abstract class C1 extends core::Object {
+  late field core::int property4;
+  late field core::int property5;
+  late field core::int property6;
+  constructor •(core::int property4, core::int property5, core::int property6) → self::C1
+    : self::C1::property4 = property4, self::C1::property5 = property5, self::C1::property6 = property6, super core::Object::•()
+    ;
+}
+abstract class C2 extends core::Object implements self::C1 {
+  synthetic constructor •() → self::C2
+    : super core::Object::•()
+    ;
+  abstract get property4() → core::int;
+  abstract get property5() → core::int;
+  abstract get property6() → core::int?;
+}
+static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart.textual_outline.expect b/pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart.textual_outline.expect
new file mode 100644
index 0000000..2045647
--- /dev/null
+++ b/pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart.textual_outline.expect
@@ -0,0 +1,39 @@
+abstract class A {
+  late int ;
+  property4;
+  late int;
+  operator? (){}
+  property5;
+  covariant late int ;
+  property6;
+  A(this.property4, this.property5, this.property6);
+}
+abstract class B1 {
+  late ;
+  final int property4;
+  late ;
+  final int property5;
+  late ;
+  final int? property6;
+  B1(this.property4, this.property5, this.property6);
+}
+abstract class B2 implements B1 {
+  void set property4(int i);
+  void set property5(int? i);
+  void set property6(int i);
+}
+abstract class C1 {
+  late int ;
+  property4;
+  late int ;
+  property5;
+  late int ;
+  property6;
+  C1(this.property4, this.property5, this.property6);
+}
+abstract class C2 implements C1 {
+  int get property4;
+  int get property5;
+  int? get property6;
+}
+main() {}
diff --git a/pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart.weak.expect b/pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart.weak.expect
new file mode 100644
index 0000000..e53ccba4
--- /dev/null
+++ b/pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart.weak.expect
@@ -0,0 +1,70 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart:30:12: Error: The type 'int?' of the inherited field 'B1.property6' is not a subtype of the type 'int' of the setter 'B2.property6'.
+//   void set property6(int i); // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart:20:19: Context: This is the declaration of the field 'B1.property6'.
+//   late final int? property6;
+//                   ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart:50:12: Error: The return type of the method 'C2.property6' is 'int?', which does not match the return type, 'int', of the overridden method, 'C1.property6'.
+// Change to a subtype of 'int'.
+//   int? get property6; // error
+//            ^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart:38:12: Context: This is the overridden method ('property6').
+//   late int property6;
+//            ^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart:50:12: Error: The type 'int?' of the getter 'C2.property6' is not a subtype of the type 'int' of the inherited setter 'C1.property6'.
+//   int? get property6; // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart:38:12: Context: This is the declaration of the setter 'C1.property6'.
+//   late int property6;
+//            ^^^^^^^^^
+//
+import self as self;
+import "dart:core" as core;
+
+abstract class A extends core::Object {
+  late field core::int property4;
+  late field core::int? property5;
+  late covariant field core::int property6;
+  constructor •(core::int property4, core::int? property5, core::int property6) → self::A
+    : self::A::property4 = property4, self::A::property5 = property5, self::A::property6 = property6, super core::Object::•()
+    ;
+}
+abstract class B1 extends core::Object {
+  late final [setter] field core::int property4;
+  late final [setter] field core::int property5;
+  late final [setter] field core::int? property6;
+  constructor •(core::int property4, core::int property5, core::int? property6) → self::B1
+    : self::B1::property4 = property4, self::B1::property5 = property5, self::B1::property6 = property6, super core::Object::•()
+    ;
+}
+abstract class B2 extends core::Object implements self::B1 {
+  synthetic constructor •() → self::B2
+    : super core::Object::•()
+    ;
+  abstract set property4(core::int i) → void;
+  abstract set property5(core::int? i) → void;
+  abstract set property6(core::int i) → void;
+}
+abstract class C1 extends core::Object {
+  late field core::int property4;
+  late field core::int property5;
+  late field core::int property6;
+  constructor •(core::int property4, core::int property5, core::int property6) → self::C1
+    : self::C1::property4 = property4, self::C1::property5 = property5, self::C1::property6 = property6, super core::Object::•()
+    ;
+}
+abstract class C2 extends core::Object implements self::C1 {
+  synthetic constructor •() → self::C2
+    : super core::Object::•()
+    ;
+  abstract get property4() → core::int;
+  abstract get property5() → core::int;
+  abstract get property6() → core::int?;
+}
+static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart.weak.transformed.expect b/pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart.weak.transformed.expect
new file mode 100644
index 0000000..e53ccba4
--- /dev/null
+++ b/pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart.weak.transformed.expect
@@ -0,0 +1,70 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart:30:12: Error: The type 'int?' of the inherited field 'B1.property6' is not a subtype of the type 'int' of the setter 'B2.property6'.
+//   void set property6(int i); // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart:20:19: Context: This is the declaration of the field 'B1.property6'.
+//   late final int? property6;
+//                   ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart:50:12: Error: The return type of the method 'C2.property6' is 'int?', which does not match the return type, 'int', of the overridden method, 'C1.property6'.
+// Change to a subtype of 'int'.
+//   int? get property6; // error
+//            ^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart:38:12: Context: This is the overridden method ('property6').
+//   late int property6;
+//            ^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart:50:12: Error: The type 'int?' of the getter 'C2.property6' is not a subtype of the type 'int' of the inherited setter 'C1.property6'.
+//   int? get property6; // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_late.dart:38:12: Context: This is the declaration of the setter 'C1.property6'.
+//   late int property6;
+//            ^^^^^^^^^
+//
+import self as self;
+import "dart:core" as core;
+
+abstract class A extends core::Object {
+  late field core::int property4;
+  late field core::int? property5;
+  late covariant field core::int property6;
+  constructor •(core::int property4, core::int? property5, core::int property6) → self::A
+    : self::A::property4 = property4, self::A::property5 = property5, self::A::property6 = property6, super core::Object::•()
+    ;
+}
+abstract class B1 extends core::Object {
+  late final [setter] field core::int property4;
+  late final [setter] field core::int property5;
+  late final [setter] field core::int? property6;
+  constructor •(core::int property4, core::int property5, core::int? property6) → self::B1
+    : self::B1::property4 = property4, self::B1::property5 = property5, self::B1::property6 = property6, super core::Object::•()
+    ;
+}
+abstract class B2 extends core::Object implements self::B1 {
+  synthetic constructor •() → self::B2
+    : super core::Object::•()
+    ;
+  abstract set property4(core::int i) → void;
+  abstract set property5(core::int? i) → void;
+  abstract set property6(core::int i) → void;
+}
+abstract class C1 extends core::Object {
+  late field core::int property4;
+  late field core::int property5;
+  late field core::int property6;
+  constructor •(core::int property4, core::int property5, core::int property6) → self::C1
+    : self::C1::property4 = property4, self::C1::property5 = property5, self::C1::property6 = property6, super core::Object::•()
+    ;
+}
+abstract class C2 extends core::Object implements self::C1 {
+  synthetic constructor •() → self::C2
+    : super core::Object::•()
+    ;
+  abstract get property4() → core::int;
+  abstract get property5() → core::int;
+  abstract get property6() → core::int?;
+}
+static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart b/pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart
new file mode 100644
index 0000000..364f0c6
--- /dev/null
+++ b/pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart
@@ -0,0 +1,109 @@
+// 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.
+
+abstract class A {
+  int get property1; // ok
+
+  void set property1(int i);
+
+  int get property2; // ok
+
+  void set property2(int? i);
+
+  int? get property3; // error
+
+  void set property3(int i);
+
+  int property4; // ok
+
+  int? property5; // ok
+
+  covariant int property6; // ok
+
+  A(this.property4, this.property5, this.property6);
+}
+
+abstract class B1 {
+  int get property1;
+
+  int get property2;
+
+  int? get property3;
+
+  final int property4;
+
+  final int property5;
+
+  final int? property6;
+
+  B1(this.property4, this.property5, this.property6);
+}
+
+abstract class B2 implements B1 {
+  void set property1(int i); // ok
+
+  void set property2(int? i); // ok
+
+  void set property3(int i); // error
+
+  void set property4(int i); // ok
+
+  void set property5(int? i); // ok
+
+  void set property6(int i); // error
+}
+
+abstract class C1 {
+  void set property1(int i);
+
+  void set property2(int? i);
+
+  void set property3(int i);
+
+  int property4;
+
+  int? property5;
+
+  int property6;
+
+  C1(this.property4, this.property5, this.property6);
+}
+
+abstract class C2 implements C1 {
+  int get property1; // ok
+
+  int get property2; // ok
+
+  int? get property3; // error
+
+  int get property4; // ok
+
+  int get property5; // ok
+
+  // This results in two errors; one for the getter/setter type mismatch and one
+  // for the getter override.
+  int? get property6; // error
+}
+
+abstract class D1 {
+  int get property1;
+
+  int get property2;
+
+  int? get property3;
+}
+
+abstract class D2 {
+  void set property1(int i);
+
+  void set property2(int? i);
+
+  void set property3(int i);
+}
+
+abstract class D3 implements D1, D2 /* error on property3 */ {}
+
+abstract class D4 implements D3 /* no need for error on property3 */ {}
+
+main() {}
diff --git a/pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart.outline.expect b/pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart.outline.expect
new file mode 100644
index 0000000..30e3ae5
--- /dev/null
+++ b/pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart.outline.expect
@@ -0,0 +1,147 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:14:12: Error: The type 'int?' of the getter 'A.property3' is not a subtype of the type 'int' of the setter 'A.property3'.
+//   int? get property3; // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:16:12: Context: This is the declaration of the setter 'A.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:48:12: Error: The type 'int?' of the inherited getter 'B1.property3' is not a subtype of the type 'int' of the setter 'B2.property3'.
+//   void set property3(int i); // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:32:12: Context: This is the declaration of the getter 'B1.property3'.
+//   int? get property3;
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:54:12: Error: The type 'int?' of the inherited field 'B1.property6' is not a subtype of the type 'int' of the setter 'B2.property6'.
+//   void set property6(int i); // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:38:14: Context: This is the declaration of the field 'B1.property6'.
+//   final int? property6;
+//              ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:78:12: Error: The type 'int?' of the getter 'C2.property3' is not a subtype of the type 'int' of the inherited setter 'C1.property3'.
+//   int? get property3; // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:62:12: Context: This is the declaration of the setter 'C1.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:86:12: Error: The return type of the method 'C2.property6' is 'int?', which does not match the return type, 'int', of the overridden method, 'C1.property6'.
+// Change to a subtype of 'int'.
+//   int? get property6; // error
+//            ^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:68:7: Context: This is the overridden method ('property6').
+//   int property6;
+//       ^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:86:12: Error: The type 'int?' of the getter 'C2.property6' is not a subtype of the type 'int' of the inherited setter 'C1.property6'.
+//   int? get property6; // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:68:7: Context: This is the declaration of the setter 'C1.property6'.
+//   int property6;
+//       ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:105:16: Error: The type 'int?' of the inherited getter 'D1.property3' is not a subtype of the type 'int' of the inherited setter 'D2.property3'.
+// abstract class D3 implements D1, D2 /* error on property3 */ {}
+//                ^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:94:12: Context: This is the declaration of the getter 'D1.property3'.
+//   int? get property3;
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:102:12: Context: This is the declaration of the setter 'D2.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:107:16: Error: The type 'int?' of the inherited getter 'D1.property3' is not a subtype of the type 'int' of the inherited setter 'D2.property3'.
+// abstract class D4 implements D3 /* no need for error on property3 */ {}
+//                ^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:94:12: Context: This is the declaration of the getter 'D1.property3'.
+//   int? get property3;
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:102:12: Context: This is the declaration of the setter 'D2.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+import self as self;
+import "dart:core" as core;
+
+abstract class A extends core::Object {
+  field core::int property4;
+  field core::int? property5;
+  covariant field core::int property6;
+  constructor •(core::int property4, core::int? property5, core::int property6) → self::A
+    ;
+  abstract get property1() → core::int;
+  abstract set property1(core::int i) → void;
+  abstract get property2() → core::int;
+  abstract set property2(core::int? i) → void;
+  abstract get property3() → core::int?;
+  abstract set property3(core::int i) → void;
+}
+abstract class B1 extends core::Object {
+  final field core::int property4;
+  final field core::int property5;
+  final field core::int? property6;
+  constructor •(core::int property4, core::int property5, core::int? property6) → self::B1
+    ;
+  abstract get property1() → core::int;
+  abstract get property2() → core::int;
+  abstract get property3() → core::int?;
+}
+abstract class B2 extends core::Object implements self::B1 {
+  synthetic constructor •() → self::B2
+    ;
+  abstract set property1(core::int i) → void;
+  abstract set property2(core::int? i) → void;
+  abstract set property3(core::int i) → void;
+  abstract set property4(core::int i) → void;
+  abstract set property5(core::int? i) → void;
+  abstract set property6(core::int i) → void;
+}
+abstract class C1 extends core::Object {
+  field core::int property4;
+  field core::int? property5;
+  field core::int property6;
+  constructor •(core::int property4, core::int? property5, core::int property6) → self::C1
+    ;
+  abstract set property1(core::int i) → void;
+  abstract set property2(core::int? i) → void;
+  abstract set property3(core::int i) → void;
+}
+abstract class C2 extends core::Object implements self::C1 {
+  synthetic constructor •() → self::C2
+    ;
+  abstract get property1() → core::int;
+  abstract get property2() → core::int;
+  abstract get property3() → core::int?;
+  abstract get property4() → core::int;
+  abstract get property5() → core::int;
+  abstract get property6() → core::int?;
+}
+abstract class D1 extends core::Object {
+  synthetic constructor •() → self::D1
+    ;
+  abstract get property1() → core::int;
+  abstract get property2() → core::int;
+  abstract get property3() → core::int?;
+}
+abstract class D2 extends core::Object {
+  synthetic constructor •() → self::D2
+    ;
+  abstract set property1(core::int i) → void;
+  abstract set property2(core::int? i) → void;
+  abstract set property3(core::int i) → void;
+}
+abstract class D3 extends core::Object implements self::D1, self::D2 {
+  synthetic constructor •() → self::D3
+    ;
+}
+abstract class D4 extends core::Object implements self::D3 {
+  synthetic constructor •() → self::D4
+    ;
+}
+static method main() → dynamic
+  ;
diff --git a/pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart.strong.expect b/pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart.strong.expect
new file mode 100644
index 0000000..89fd1f6
--- /dev/null
+++ b/pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart.strong.expect
@@ -0,0 +1,155 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:14:12: Error: The type 'int?' of the getter 'A.property3' is not a subtype of the type 'int' of the setter 'A.property3'.
+//   int? get property3; // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:16:12: Context: This is the declaration of the setter 'A.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:48:12: Error: The type 'int?' of the inherited getter 'B1.property3' is not a subtype of the type 'int' of the setter 'B2.property3'.
+//   void set property3(int i); // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:32:12: Context: This is the declaration of the getter 'B1.property3'.
+//   int? get property3;
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:54:12: Error: The type 'int?' of the inherited field 'B1.property6' is not a subtype of the type 'int' of the setter 'B2.property6'.
+//   void set property6(int i); // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:38:14: Context: This is the declaration of the field 'B1.property6'.
+//   final int? property6;
+//              ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:78:12: Error: The type 'int?' of the getter 'C2.property3' is not a subtype of the type 'int' of the inherited setter 'C1.property3'.
+//   int? get property3; // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:62:12: Context: This is the declaration of the setter 'C1.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:86:12: Error: The return type of the method 'C2.property6' is 'int?', which does not match the return type, 'int', of the overridden method, 'C1.property6'.
+// Change to a subtype of 'int'.
+//   int? get property6; // error
+//            ^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:68:7: Context: This is the overridden method ('property6').
+//   int property6;
+//       ^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:86:12: Error: The type 'int?' of the getter 'C2.property6' is not a subtype of the type 'int' of the inherited setter 'C1.property6'.
+//   int? get property6; // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:68:7: Context: This is the declaration of the setter 'C1.property6'.
+//   int property6;
+//       ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:105:16: Error: The type 'int?' of the inherited getter 'D1.property3' is not a subtype of the type 'int' of the inherited setter 'D2.property3'.
+// abstract class D3 implements D1, D2 /* error on property3 */ {}
+//                ^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:94:12: Context: This is the declaration of the getter 'D1.property3'.
+//   int? get property3;
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:102:12: Context: This is the declaration of the setter 'D2.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:107:16: Error: The type 'int?' of the inherited getter 'D1.property3' is not a subtype of the type 'int' of the inherited setter 'D2.property3'.
+// abstract class D4 implements D3 /* no need for error on property3 */ {}
+//                ^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:94:12: Context: This is the declaration of the getter 'D1.property3'.
+//   int? get property3;
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:102:12: Context: This is the declaration of the setter 'D2.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+import self as self;
+import "dart:core" as core;
+
+abstract class A extends core::Object {
+  field core::int property4;
+  field core::int? property5;
+  covariant field core::int property6;
+  constructor •(core::int property4, core::int? property5, core::int property6) → self::A
+    : self::A::property4 = property4, self::A::property5 = property5, self::A::property6 = property6, super core::Object::•()
+    ;
+  abstract get property1() → core::int;
+  abstract set property1(core::int i) → void;
+  abstract get property2() → core::int;
+  abstract set property2(core::int? i) → void;
+  abstract get property3() → core::int?;
+  abstract set property3(core::int i) → void;
+}
+abstract class B1 extends core::Object {
+  final field core::int property4;
+  final field core::int property5;
+  final field core::int? property6;
+  constructor •(core::int property4, core::int property5, core::int? property6) → self::B1
+    : self::B1::property4 = property4, self::B1::property5 = property5, self::B1::property6 = property6, super core::Object::•()
+    ;
+  abstract get property1() → core::int;
+  abstract get property2() → core::int;
+  abstract get property3() → core::int?;
+}
+abstract class B2 extends core::Object implements self::B1 {
+  synthetic constructor •() → self::B2
+    : super core::Object::•()
+    ;
+  abstract set property1(core::int i) → void;
+  abstract set property2(core::int? i) → void;
+  abstract set property3(core::int i) → void;
+  abstract set property4(core::int i) → void;
+  abstract set property5(core::int? i) → void;
+  abstract set property6(core::int i) → void;
+}
+abstract class C1 extends core::Object {
+  field core::int property4;
+  field core::int? property5;
+  field core::int property6;
+  constructor •(core::int property4, core::int? property5, core::int property6) → self::C1
+    : self::C1::property4 = property4, self::C1::property5 = property5, self::C1::property6 = property6, super core::Object::•()
+    ;
+  abstract set property1(core::int i) → void;
+  abstract set property2(core::int? i) → void;
+  abstract set property3(core::int i) → void;
+}
+abstract class C2 extends core::Object implements self::C1 {
+  synthetic constructor •() → self::C2
+    : super core::Object::•()
+    ;
+  abstract get property1() → core::int;
+  abstract get property2() → core::int;
+  abstract get property3() → core::int?;
+  abstract get property4() → core::int;
+  abstract get property5() → core::int;
+  abstract get property6() → core::int?;
+}
+abstract class D1 extends core::Object {
+  synthetic constructor •() → self::D1
+    : super core::Object::•()
+    ;
+  abstract get property1() → core::int;
+  abstract get property2() → core::int;
+  abstract get property3() → core::int?;
+}
+abstract class D2 extends core::Object {
+  synthetic constructor •() → self::D2
+    : super core::Object::•()
+    ;
+  abstract set property1(core::int i) → void;
+  abstract set property2(core::int? i) → void;
+  abstract set property3(core::int i) → void;
+}
+abstract class D3 extends core::Object implements self::D1, self::D2 {
+  synthetic constructor •() → self::D3
+    : super core::Object::•()
+    ;
+}
+abstract class D4 extends core::Object implements self::D3 {
+  synthetic constructor •() → self::D4
+    : super core::Object::•()
+    ;
+}
+static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart.strong.transformed.expect b/pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart.strong.transformed.expect
new file mode 100644
index 0000000..89fd1f6
--- /dev/null
+++ b/pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart.strong.transformed.expect
@@ -0,0 +1,155 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:14:12: Error: The type 'int?' of the getter 'A.property3' is not a subtype of the type 'int' of the setter 'A.property3'.
+//   int? get property3; // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:16:12: Context: This is the declaration of the setter 'A.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:48:12: Error: The type 'int?' of the inherited getter 'B1.property3' is not a subtype of the type 'int' of the setter 'B2.property3'.
+//   void set property3(int i); // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:32:12: Context: This is the declaration of the getter 'B1.property3'.
+//   int? get property3;
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:54:12: Error: The type 'int?' of the inherited field 'B1.property6' is not a subtype of the type 'int' of the setter 'B2.property6'.
+//   void set property6(int i); // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:38:14: Context: This is the declaration of the field 'B1.property6'.
+//   final int? property6;
+//              ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:78:12: Error: The type 'int?' of the getter 'C2.property3' is not a subtype of the type 'int' of the inherited setter 'C1.property3'.
+//   int? get property3; // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:62:12: Context: This is the declaration of the setter 'C1.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:86:12: Error: The return type of the method 'C2.property6' is 'int?', which does not match the return type, 'int', of the overridden method, 'C1.property6'.
+// Change to a subtype of 'int'.
+//   int? get property6; // error
+//            ^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:68:7: Context: This is the overridden method ('property6').
+//   int property6;
+//       ^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:86:12: Error: The type 'int?' of the getter 'C2.property6' is not a subtype of the type 'int' of the inherited setter 'C1.property6'.
+//   int? get property6; // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:68:7: Context: This is the declaration of the setter 'C1.property6'.
+//   int property6;
+//       ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:105:16: Error: The type 'int?' of the inherited getter 'D1.property3' is not a subtype of the type 'int' of the inherited setter 'D2.property3'.
+// abstract class D3 implements D1, D2 /* error on property3 */ {}
+//                ^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:94:12: Context: This is the declaration of the getter 'D1.property3'.
+//   int? get property3;
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:102:12: Context: This is the declaration of the setter 'D2.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:107:16: Error: The type 'int?' of the inherited getter 'D1.property3' is not a subtype of the type 'int' of the inherited setter 'D2.property3'.
+// abstract class D4 implements D3 /* no need for error on property3 */ {}
+//                ^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:94:12: Context: This is the declaration of the getter 'D1.property3'.
+//   int? get property3;
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:102:12: Context: This is the declaration of the setter 'D2.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+import self as self;
+import "dart:core" as core;
+
+abstract class A extends core::Object {
+  field core::int property4;
+  field core::int? property5;
+  covariant field core::int property6;
+  constructor •(core::int property4, core::int? property5, core::int property6) → self::A
+    : self::A::property4 = property4, self::A::property5 = property5, self::A::property6 = property6, super core::Object::•()
+    ;
+  abstract get property1() → core::int;
+  abstract set property1(core::int i) → void;
+  abstract get property2() → core::int;
+  abstract set property2(core::int? i) → void;
+  abstract get property3() → core::int?;
+  abstract set property3(core::int i) → void;
+}
+abstract class B1 extends core::Object {
+  final field core::int property4;
+  final field core::int property5;
+  final field core::int? property6;
+  constructor •(core::int property4, core::int property5, core::int? property6) → self::B1
+    : self::B1::property4 = property4, self::B1::property5 = property5, self::B1::property6 = property6, super core::Object::•()
+    ;
+  abstract get property1() → core::int;
+  abstract get property2() → core::int;
+  abstract get property3() → core::int?;
+}
+abstract class B2 extends core::Object implements self::B1 {
+  synthetic constructor •() → self::B2
+    : super core::Object::•()
+    ;
+  abstract set property1(core::int i) → void;
+  abstract set property2(core::int? i) → void;
+  abstract set property3(core::int i) → void;
+  abstract set property4(core::int i) → void;
+  abstract set property5(core::int? i) → void;
+  abstract set property6(core::int i) → void;
+}
+abstract class C1 extends core::Object {
+  field core::int property4;
+  field core::int? property5;
+  field core::int property6;
+  constructor •(core::int property4, core::int? property5, core::int property6) → self::C1
+    : self::C1::property4 = property4, self::C1::property5 = property5, self::C1::property6 = property6, super core::Object::•()
+    ;
+  abstract set property1(core::int i) → void;
+  abstract set property2(core::int? i) → void;
+  abstract set property3(core::int i) → void;
+}
+abstract class C2 extends core::Object implements self::C1 {
+  synthetic constructor •() → self::C2
+    : super core::Object::•()
+    ;
+  abstract get property1() → core::int;
+  abstract get property2() → core::int;
+  abstract get property3() → core::int?;
+  abstract get property4() → core::int;
+  abstract get property5() → core::int;
+  abstract get property6() → core::int?;
+}
+abstract class D1 extends core::Object {
+  synthetic constructor •() → self::D1
+    : super core::Object::•()
+    ;
+  abstract get property1() → core::int;
+  abstract get property2() → core::int;
+  abstract get property3() → core::int?;
+}
+abstract class D2 extends core::Object {
+  synthetic constructor •() → self::D2
+    : super core::Object::•()
+    ;
+  abstract set property1(core::int i) → void;
+  abstract set property2(core::int? i) → void;
+  abstract set property3(core::int i) → void;
+}
+abstract class D3 extends core::Object implements self::D1, self::D2 {
+  synthetic constructor •() → self::D3
+    : super core::Object::•()
+    ;
+}
+abstract class D4 extends core::Object implements self::D3 {
+  synthetic constructor •() → self::D4
+    : super core::Object::•()
+    ;
+}
+static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart.textual_outline.expect b/pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart.textual_outline.expect
new file mode 100644
index 0000000..b6be33e
--- /dev/null
+++ b/pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart.textual_outline.expect
@@ -0,0 +1,68 @@
+abstract class A {
+  int get property1;
+  void set property1(int i);
+  int get property2;
+  void set property2(int? i);
+  int? get property3;
+  void set property3(int i);
+  int property4;
+  int? property5;
+  covariant int property6;
+  A(this.property4, this.property5, this.property6);
+}
+
+abstract class B1 {
+  int get property1;
+  int get property2;
+  int? get property3;
+  final int property4;
+  final int property5;
+  final int? property6;
+  B1(this.property4, this.property5, this.property6);
+}
+
+abstract class B2 implements B1 {
+  void set property1(int i);
+  void set property2(int? i);
+  void set property3(int i);
+  void set property4(int i);
+  void set property5(int? i);
+  void set property6(int i);
+}
+
+abstract class C1 {
+  void set property1(int i);
+  void set property2(int? i);
+  void set property3(int i);
+  int property4;
+  int? property5;
+  int property6;
+  C1(this.property4, this.property5, this.property6);
+}
+
+abstract class C2 implements C1 {
+  int get property1;
+  int get property2;
+  int? get property3;
+  int get property4;
+  int get property5;
+  int? get property6;
+}
+
+abstract class D1 {
+  int get property1;
+  int get property2;
+  int? get property3;
+}
+
+abstract class D2 {
+  void set property1(int i);
+  void set property2(int? i);
+  void set property3(int i);
+}
+
+abstract class D3 implements D1, D2 {}
+
+abstract class D4 implements D3 {}
+
+main() {}
diff --git a/pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart.textual_outline_modelled.expect b/pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart.textual_outline_modelled.expect
new file mode 100644
index 0000000..a071d28
--- /dev/null
+++ b/pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart.textual_outline_modelled.expect
@@ -0,0 +1,68 @@
+abstract class A {
+  A(this.property4, this.property5, this.property6);
+  covariant int property6;
+  int? get property3;
+  int? property5;
+  int get property1;
+  int get property2;
+  int property4;
+  void set property1(int i);
+  void set property2(int? i);
+  void set property3(int i);
+}
+
+abstract class B1 {
+  B1(this.property4, this.property5, this.property6);
+  final int? property6;
+  final int property4;
+  final int property5;
+  int? get property3;
+  int get property1;
+  int get property2;
+}
+
+abstract class B2 implements B1 {
+  void set property1(int i);
+  void set property2(int? i);
+  void set property3(int i);
+  void set property4(int i);
+  void set property5(int? i);
+  void set property6(int i);
+}
+
+abstract class C1 {
+  C1(this.property4, this.property5, this.property6);
+  int? property5;
+  int property4;
+  int property6;
+  void set property1(int i);
+  void set property2(int? i);
+  void set property3(int i);
+}
+
+abstract class C2 implements C1 {
+  int? get property3;
+  int? get property6;
+  int get property1;
+  int get property2;
+  int get property4;
+  int get property5;
+}
+
+abstract class D1 {
+  int? get property3;
+  int get property1;
+  int get property2;
+}
+
+abstract class D2 {
+  void set property1(int i);
+  void set property2(int? i);
+  void set property3(int i);
+}
+
+abstract class D3 implements D1, D2 {}
+
+abstract class D4 implements D3 {}
+
+main() {}
diff --git a/pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart.weak.expect b/pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart.weak.expect
new file mode 100644
index 0000000..89fd1f6
--- /dev/null
+++ b/pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart.weak.expect
@@ -0,0 +1,155 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:14:12: Error: The type 'int?' of the getter 'A.property3' is not a subtype of the type 'int' of the setter 'A.property3'.
+//   int? get property3; // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:16:12: Context: This is the declaration of the setter 'A.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:48:12: Error: The type 'int?' of the inherited getter 'B1.property3' is not a subtype of the type 'int' of the setter 'B2.property3'.
+//   void set property3(int i); // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:32:12: Context: This is the declaration of the getter 'B1.property3'.
+//   int? get property3;
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:54:12: Error: The type 'int?' of the inherited field 'B1.property6' is not a subtype of the type 'int' of the setter 'B2.property6'.
+//   void set property6(int i); // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:38:14: Context: This is the declaration of the field 'B1.property6'.
+//   final int? property6;
+//              ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:78:12: Error: The type 'int?' of the getter 'C2.property3' is not a subtype of the type 'int' of the inherited setter 'C1.property3'.
+//   int? get property3; // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:62:12: Context: This is the declaration of the setter 'C1.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:86:12: Error: The return type of the method 'C2.property6' is 'int?', which does not match the return type, 'int', of the overridden method, 'C1.property6'.
+// Change to a subtype of 'int'.
+//   int? get property6; // error
+//            ^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:68:7: Context: This is the overridden method ('property6').
+//   int property6;
+//       ^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:86:12: Error: The type 'int?' of the getter 'C2.property6' is not a subtype of the type 'int' of the inherited setter 'C1.property6'.
+//   int? get property6; // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:68:7: Context: This is the declaration of the setter 'C1.property6'.
+//   int property6;
+//       ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:105:16: Error: The type 'int?' of the inherited getter 'D1.property3' is not a subtype of the type 'int' of the inherited setter 'D2.property3'.
+// abstract class D3 implements D1, D2 /* error on property3 */ {}
+//                ^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:94:12: Context: This is the declaration of the getter 'D1.property3'.
+//   int? get property3;
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:102:12: Context: This is the declaration of the setter 'D2.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:107:16: Error: The type 'int?' of the inherited getter 'D1.property3' is not a subtype of the type 'int' of the inherited setter 'D2.property3'.
+// abstract class D4 implements D3 /* no need for error on property3 */ {}
+//                ^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:94:12: Context: This is the declaration of the getter 'D1.property3'.
+//   int? get property3;
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:102:12: Context: This is the declaration of the setter 'D2.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+import self as self;
+import "dart:core" as core;
+
+abstract class A extends core::Object {
+  field core::int property4;
+  field core::int? property5;
+  covariant field core::int property6;
+  constructor •(core::int property4, core::int? property5, core::int property6) → self::A
+    : self::A::property4 = property4, self::A::property5 = property5, self::A::property6 = property6, super core::Object::•()
+    ;
+  abstract get property1() → core::int;
+  abstract set property1(core::int i) → void;
+  abstract get property2() → core::int;
+  abstract set property2(core::int? i) → void;
+  abstract get property3() → core::int?;
+  abstract set property3(core::int i) → void;
+}
+abstract class B1 extends core::Object {
+  final field core::int property4;
+  final field core::int property5;
+  final field core::int? property6;
+  constructor •(core::int property4, core::int property5, core::int? property6) → self::B1
+    : self::B1::property4 = property4, self::B1::property5 = property5, self::B1::property6 = property6, super core::Object::•()
+    ;
+  abstract get property1() → core::int;
+  abstract get property2() → core::int;
+  abstract get property3() → core::int?;
+}
+abstract class B2 extends core::Object implements self::B1 {
+  synthetic constructor •() → self::B2
+    : super core::Object::•()
+    ;
+  abstract set property1(core::int i) → void;
+  abstract set property2(core::int? i) → void;
+  abstract set property3(core::int i) → void;
+  abstract set property4(core::int i) → void;
+  abstract set property5(core::int? i) → void;
+  abstract set property6(core::int i) → void;
+}
+abstract class C1 extends core::Object {
+  field core::int property4;
+  field core::int? property5;
+  field core::int property6;
+  constructor •(core::int property4, core::int? property5, core::int property6) → self::C1
+    : self::C1::property4 = property4, self::C1::property5 = property5, self::C1::property6 = property6, super core::Object::•()
+    ;
+  abstract set property1(core::int i) → void;
+  abstract set property2(core::int? i) → void;
+  abstract set property3(core::int i) → void;
+}
+abstract class C2 extends core::Object implements self::C1 {
+  synthetic constructor •() → self::C2
+    : super core::Object::•()
+    ;
+  abstract get property1() → core::int;
+  abstract get property2() → core::int;
+  abstract get property3() → core::int?;
+  abstract get property4() → core::int;
+  abstract get property5() → core::int;
+  abstract get property6() → core::int?;
+}
+abstract class D1 extends core::Object {
+  synthetic constructor •() → self::D1
+    : super core::Object::•()
+    ;
+  abstract get property1() → core::int;
+  abstract get property2() → core::int;
+  abstract get property3() → core::int?;
+}
+abstract class D2 extends core::Object {
+  synthetic constructor •() → self::D2
+    : super core::Object::•()
+    ;
+  abstract set property1(core::int i) → void;
+  abstract set property2(core::int? i) → void;
+  abstract set property3(core::int i) → void;
+}
+abstract class D3 extends core::Object implements self::D1, self::D2 {
+  synthetic constructor •() → self::D3
+    : super core::Object::•()
+    ;
+}
+abstract class D4 extends core::Object implements self::D3 {
+  synthetic constructor •() → self::D4
+    : super core::Object::•()
+    ;
+}
+static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart.weak.transformed.expect b/pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart.weak.transformed.expect
new file mode 100644
index 0000000..89fd1f6
--- /dev/null
+++ b/pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart.weak.transformed.expect
@@ -0,0 +1,155 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:14:12: Error: The type 'int?' of the getter 'A.property3' is not a subtype of the type 'int' of the setter 'A.property3'.
+//   int? get property3; // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:16:12: Context: This is the declaration of the setter 'A.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:48:12: Error: The type 'int?' of the inherited getter 'B1.property3' is not a subtype of the type 'int' of the setter 'B2.property3'.
+//   void set property3(int i); // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:32:12: Context: This is the declaration of the getter 'B1.property3'.
+//   int? get property3;
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:54:12: Error: The type 'int?' of the inherited field 'B1.property6' is not a subtype of the type 'int' of the setter 'B2.property6'.
+//   void set property6(int i); // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:38:14: Context: This is the declaration of the field 'B1.property6'.
+//   final int? property6;
+//              ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:78:12: Error: The type 'int?' of the getter 'C2.property3' is not a subtype of the type 'int' of the inherited setter 'C1.property3'.
+//   int? get property3; // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:62:12: Context: This is the declaration of the setter 'C1.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:86:12: Error: The return type of the method 'C2.property6' is 'int?', which does not match the return type, 'int', of the overridden method, 'C1.property6'.
+// Change to a subtype of 'int'.
+//   int? get property6; // error
+//            ^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:68:7: Context: This is the overridden method ('property6').
+//   int property6;
+//       ^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:86:12: Error: The type 'int?' of the getter 'C2.property6' is not a subtype of the type 'int' of the inherited setter 'C1.property6'.
+//   int? get property6; // error
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:68:7: Context: This is the declaration of the setter 'C1.property6'.
+//   int property6;
+//       ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:105:16: Error: The type 'int?' of the inherited getter 'D1.property3' is not a subtype of the type 'int' of the inherited setter 'D2.property3'.
+// abstract class D3 implements D1, D2 /* error on property3 */ {}
+//                ^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:94:12: Context: This is the declaration of the getter 'D1.property3'.
+//   int? get property3;
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:102:12: Context: This is the declaration of the setter 'D2.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:107:16: Error: The type 'int?' of the inherited getter 'D1.property3' is not a subtype of the type 'int' of the inherited setter 'D2.property3'.
+// abstract class D4 implements D3 /* no need for error on property3 */ {}
+//                ^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:94:12: Context: This is the declaration of the getter 'D1.property3'.
+//   int? get property3;
+//            ^^^^^^^^^
+// pkg/front_end/testcases/nnbd/getter_vs_setter_type_nnbd.dart:102:12: Context: This is the declaration of the setter 'D2.property3'.
+//   void set property3(int i);
+//            ^^^^^^^^^
+//
+import self as self;
+import "dart:core" as core;
+
+abstract class A extends core::Object {
+  field core::int property4;
+  field core::int? property5;
+  covariant field core::int property6;
+  constructor •(core::int property4, core::int? property5, core::int property6) → self::A
+    : self::A::property4 = property4, self::A::property5 = property5, self::A::property6 = property6, super core::Object::•()
+    ;
+  abstract get property1() → core::int;
+  abstract set property1(core::int i) → void;
+  abstract get property2() → core::int;
+  abstract set property2(core::int? i) → void;
+  abstract get property3() → core::int?;
+  abstract set property3(core::int i) → void;
+}
+abstract class B1 extends core::Object {
+  final field core::int property4;
+  final field core::int property5;
+  final field core::int? property6;
+  constructor •(core::int property4, core::int property5, core::int? property6) → self::B1
+    : self::B1::property4 = property4, self::B1::property5 = property5, self::B1::property6 = property6, super core::Object::•()
+    ;
+  abstract get property1() → core::int;
+  abstract get property2() → core::int;
+  abstract get property3() → core::int?;
+}
+abstract class B2 extends core::Object implements self::B1 {
+  synthetic constructor •() → self::B2
+    : super core::Object::•()
+    ;
+  abstract set property1(core::int i) → void;
+  abstract set property2(core::int? i) → void;
+  abstract set property3(core::int i) → void;
+  abstract set property4(core::int i) → void;
+  abstract set property5(core::int? i) → void;
+  abstract set property6(core::int i) → void;
+}
+abstract class C1 extends core::Object {
+  field core::int property4;
+  field core::int? property5;
+  field core::int property6;
+  constructor •(core::int property4, core::int? property5, core::int property6) → self::C1
+    : self::C1::property4 = property4, self::C1::property5 = property5, self::C1::property6 = property6, super core::Object::•()
+    ;
+  abstract set property1(core::int i) → void;
+  abstract set property2(core::int? i) → void;
+  abstract set property3(core::int i) → void;
+}
+abstract class C2 extends core::Object implements self::C1 {
+  synthetic constructor •() → self::C2
+    : super core::Object::•()
+    ;
+  abstract get property1() → core::int;
+  abstract get property2() → core::int;
+  abstract get property3() → core::int?;
+  abstract get property4() → core::int;
+  abstract get property5() → core::int;
+  abstract get property6() → core::int?;
+}
+abstract class D1 extends core::Object {
+  synthetic constructor •() → self::D1
+    : super core::Object::•()
+    ;
+  abstract get property1() → core::int;
+  abstract get property2() → core::int;
+  abstract get property3() → core::int?;
+}
+abstract class D2 extends core::Object {
+  synthetic constructor •() → self::D2
+    : super core::Object::•()
+    ;
+  abstract set property1(core::int i) → void;
+  abstract set property2(core::int? i) → void;
+  abstract set property3(core::int i) → void;
+}
+abstract class D3 extends core::Object implements self::D1, self::D2 {
+  synthetic constructor •() → self::D3
+    : super core::Object::•()
+    ;
+}
+abstract class D4 extends core::Object implements self::D3 {
+  synthetic constructor •() → self::D4
+    : super core::Object::•()
+    ;
+}
+static method main() → dynamic {}
diff --git a/pkg/front_end/testcases/nnbd_mixed/member_inheritance_from_opt_in.dart.weak.expect b/pkg/front_end/testcases/nnbd_mixed/member_inheritance_from_opt_in.dart.weak.expect
index c2781bb..44dc597 100644
--- a/pkg/front_end/testcases/nnbd_mixed/member_inheritance_from_opt_in.dart.weak.expect
+++ b/pkg/front_end/testcases/nnbd_mixed/member_inheritance_from_opt_in.dart.weak.expect
@@ -43,17 +43,6 @@
   get property4() → core::int*
     return 0;
   set property4(core::int* value) → void {}
-  abstract member-signature method method1() → core::int*; -> mem::Class::method1
-  abstract member-signature method method2() → core::int*; -> mem::Class::method2
-  abstract member-signature method method5a(core::int* a, core::int* b) → core::int*; -> mem::Class::method5a
-  abstract member-signature method method5b(core::int* a, [core::int* b = #C1]) → core::int*; -> mem::Class::method5b
-  abstract member-signature method method5c([core::int* a = #C2, core::int* b = #C1]) → core::int*; -> mem::Class::method5c
-  abstract member-signature method method7a(core::int* a, {core::int* b = #C1}) → core::int*; -> mem::Class::method7a
-  abstract member-signature method method7b({core::int* a = #C2, core::int* b = #C1}) → core::int*; -> mem::Class::method7b
-  abstract member-signature method method9a(core::int* a, {core::int* b = #C1}) → core::int*; -> mem::Class::method9a
-  abstract member-signature method method9b({core::int* a = #C1, core::int* b = #C1}) → core::int*; -> mem::Class::method9b
-  abstract member-signature get getter1() → core::int*; -> mem::Class::getter1
-  abstract member-signature get getter2() → core::int*; -> mem::Class::getter2
   abstract member-signature get field1() → core::int*; -> mem::Class::field1
   abstract member-signature set field1(core::int* _) → void; -> mem::Class::field1
   abstract member-signature get field2() → core::int*; -> mem::Class::field2
@@ -66,6 +55,17 @@
   abstract member-signature set property5(core::int* _) → void; -> mem::Class::property5
   abstract member-signature get property6() → core::int*; -> mem::Class::property6
   abstract member-signature set property6(core::int* _) → void; -> mem::Class::property6
+  abstract member-signature method method1() → core::int*; -> mem::Class::method1
+  abstract member-signature method method2() → core::int*; -> mem::Class::method2
+  abstract member-signature method method5a(core::int* a, core::int* b) → core::int*; -> mem::Class::method5a
+  abstract member-signature method method5b(core::int* a, [core::int* b = #C1]) → core::int*; -> mem::Class::method5b
+  abstract member-signature method method5c([core::int* a = #C2, core::int* b = #C1]) → core::int*; -> mem::Class::method5c
+  abstract member-signature method method7a(core::int* a, {core::int* b = #C1}) → core::int*; -> mem::Class::method7a
+  abstract member-signature method method7b({core::int* a = #C2, core::int* b = #C1}) → core::int*; -> mem::Class::method7b
+  abstract member-signature method method9a(core::int* a, {core::int* b = #C1}) → core::int*; -> mem::Class::method9a
+  abstract member-signature method method9b({core::int* a = #C1, core::int* b = #C1}) → core::int*; -> mem::Class::method9b
+  abstract member-signature get getter1() → core::int*; -> mem::Class::getter1
+  abstract member-signature get getter2() → core::int*; -> mem::Class::getter2
   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
diff --git a/pkg/front_end/testcases/nnbd_mixed/member_inheritance_from_opt_in.dart.weak.transformed.expect b/pkg/front_end/testcases/nnbd_mixed/member_inheritance_from_opt_in.dart.weak.transformed.expect
index c2781bb..44dc597 100644
--- a/pkg/front_end/testcases/nnbd_mixed/member_inheritance_from_opt_in.dart.weak.transformed.expect
+++ b/pkg/front_end/testcases/nnbd_mixed/member_inheritance_from_opt_in.dart.weak.transformed.expect
@@ -43,17 +43,6 @@
   get property4() → core::int*
     return 0;
   set property4(core::int* value) → void {}
-  abstract member-signature method method1() → core::int*; -> mem::Class::method1
-  abstract member-signature method method2() → core::int*; -> mem::Class::method2
-  abstract member-signature method method5a(core::int* a, core::int* b) → core::int*; -> mem::Class::method5a
-  abstract member-signature method method5b(core::int* a, [core::int* b = #C1]) → core::int*; -> mem::Class::method5b
-  abstract member-signature method method5c([core::int* a = #C2, core::int* b = #C1]) → core::int*; -> mem::Class::method5c
-  abstract member-signature method method7a(core::int* a, {core::int* b = #C1}) → core::int*; -> mem::Class::method7a
-  abstract member-signature method method7b({core::int* a = #C2, core::int* b = #C1}) → core::int*; -> mem::Class::method7b
-  abstract member-signature method method9a(core::int* a, {core::int* b = #C1}) → core::int*; -> mem::Class::method9a
-  abstract member-signature method method9b({core::int* a = #C1, core::int* b = #C1}) → core::int*; -> mem::Class::method9b
-  abstract member-signature get getter1() → core::int*; -> mem::Class::getter1
-  abstract member-signature get getter2() → core::int*; -> mem::Class::getter2
   abstract member-signature get field1() → core::int*; -> mem::Class::field1
   abstract member-signature set field1(core::int* _) → void; -> mem::Class::field1
   abstract member-signature get field2() → core::int*; -> mem::Class::field2
@@ -66,6 +55,17 @@
   abstract member-signature set property5(core::int* _) → void; -> mem::Class::property5
   abstract member-signature get property6() → core::int*; -> mem::Class::property6
   abstract member-signature set property6(core::int* _) → void; -> mem::Class::property6
+  abstract member-signature method method1() → core::int*; -> mem::Class::method1
+  abstract member-signature method method2() → core::int*; -> mem::Class::method2
+  abstract member-signature method method5a(core::int* a, core::int* b) → core::int*; -> mem::Class::method5a
+  abstract member-signature method method5b(core::int* a, [core::int* b = #C1]) → core::int*; -> mem::Class::method5b
+  abstract member-signature method method5c([core::int* a = #C2, core::int* b = #C1]) → core::int*; -> mem::Class::method5c
+  abstract member-signature method method7a(core::int* a, {core::int* b = #C1}) → core::int*; -> mem::Class::method7a
+  abstract member-signature method method7b({core::int* a = #C2, core::int* b = #C1}) → core::int*; -> mem::Class::method7b
+  abstract member-signature method method9a(core::int* a, {core::int* b = #C1}) → core::int*; -> mem::Class::method9a
+  abstract member-signature method method9b({core::int* a = #C1, core::int* b = #C1}) → core::int*; -> mem::Class::method9b
+  abstract member-signature get getter1() → core::int*; -> mem::Class::getter1
+  abstract member-signature get getter2() → core::int*; -> mem::Class::getter2
   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
diff --git a/pkg/front_end/testcases/nnbd_mixed/member_inheritance_from_opt_out.dart.weak.expect b/pkg/front_end/testcases/nnbd_mixed/member_inheritance_from_opt_out.dart.weak.expect
index 3f07aa4..a1b69ec 100644
--- a/pkg/front_end/testcases/nnbd_mixed/member_inheritance_from_opt_out.dart.weak.expect
+++ b/pkg/front_end/testcases/nnbd_mixed/member_inheritance_from_opt_out.dart.weak.expect
@@ -49,22 +49,6 @@
   synthetic constructor •() → self::Class2a
     : super opt::LegacyClass::•()
     ;
-  abstract member-signature method method1() → core::int; -> opt::LegacyClass::method1
-  abstract member-signature method method2() → core::int?; -> opt::LegacyClass::method2
-  abstract member-signature method method3a(core::int a, core::int b) → core::int; -> opt::LegacyClass::method3a
-  abstract member-signature method method3b(core::int a, [core::int b = #C1]) → core::int; -> opt::LegacyClass::method3b
-  abstract member-signature method method3c([core::int a = #C1, core::int b = #C1]) → core::int; -> opt::LegacyClass::method3c
-  abstract member-signature method method4a(core::int? a, core::int? b) → core::int?; -> opt::LegacyClass::method4a
-  abstract member-signature method method4b(core::int? a, [core::int? b = #C1]) → core::int?; -> opt::LegacyClass::method4b
-  abstract member-signature method method4c([core::int? a = #C1, core::int? b = #C1]) → core::int?; -> opt::LegacyClass::method4c
-  abstract member-signature method method5a(core::int a, {core::int b = #C1}) → core::int; -> opt::LegacyClass::method5a
-  abstract member-signature method method5b({core::int a = #C1, core::int b = #C1}) → core::int; -> opt::LegacyClass::method5b
-  abstract member-signature method method5c({core::int a = #C1, core::int b = #C1}) → core::int; -> opt::LegacyClass::method5c
-  abstract member-signature method method6a(core::int? a, {core::int? b = #C1}) → core::int?; -> opt::LegacyClass::method6a
-  abstract member-signature method method6b({core::int? a = #C1, core::int? b = #C1}) → core::int?; -> opt::LegacyClass::method6b
-  abstract member-signature method method6c({core::int? a = #C1, core::int? b = #C1}) → core::int?; -> opt::LegacyClass::method6c
-  abstract member-signature get getter1() → core::int; -> opt::LegacyClass::getter1
-  abstract member-signature get getter2() → core::int?; -> opt::LegacyClass::getter2
   abstract member-signature get field1() → core::int; -> opt::LegacyClass::field1
   abstract member-signature set field1(core::int _) → void; -> opt::LegacyClass::field1
   abstract member-signature get field2() → core::int?; -> opt::LegacyClass::field2
@@ -81,6 +65,22 @@
   abstract member-signature set property3(core::int value) → void; -> opt::LegacyClass::property3
   abstract member-signature get property4() → core::int?; -> opt::LegacyClass::property4
   abstract member-signature set property4(core::int? value) → void; -> opt::LegacyClass::property4
+  abstract member-signature method method1() → core::int; -> opt::LegacyClass::method1
+  abstract member-signature method method2() → core::int?; -> opt::LegacyClass::method2
+  abstract member-signature method method3a(core::int a, core::int b) → core::int; -> opt::LegacyClass::method3a
+  abstract member-signature method method3b(core::int a, [core::int b = #C1]) → core::int; -> opt::LegacyClass::method3b
+  abstract member-signature method method3c([core::int a = #C1, core::int b = #C1]) → core::int; -> opt::LegacyClass::method3c
+  abstract member-signature method method4a(core::int? a, core::int? b) → core::int?; -> opt::LegacyClass::method4a
+  abstract member-signature method method4b(core::int? a, [core::int? b = #C1]) → core::int?; -> opt::LegacyClass::method4b
+  abstract member-signature method method4c([core::int? a = #C1, core::int? b = #C1]) → core::int?; -> opt::LegacyClass::method4c
+  abstract member-signature method method5a(core::int a, {core::int b = #C1}) → core::int; -> opt::LegacyClass::method5a
+  abstract member-signature method method5b({core::int a = #C1, core::int b = #C1}) → core::int; -> opt::LegacyClass::method5b
+  abstract member-signature method method5c({core::int a = #C1, core::int b = #C1}) → core::int; -> opt::LegacyClass::method5c
+  abstract member-signature method method6a(core::int? a, {core::int? b = #C1}) → core::int?; -> opt::LegacyClass::method6a
+  abstract member-signature method method6b({core::int? a = #C1, core::int? b = #C1}) → core::int?; -> opt::LegacyClass::method6b
+  abstract member-signature method method6c({core::int? a = #C1, core::int? b = #C1}) → core::int?; -> opt::LegacyClass::method6c
+  abstract member-signature get getter1() → core::int; -> opt::LegacyClass::getter1
+  abstract member-signature get getter2() → core::int?; -> opt::LegacyClass::getter2
   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
diff --git a/pkg/front_end/testcases/nnbd_mixed/member_inheritance_from_opt_out.dart.weak.transformed.expect b/pkg/front_end/testcases/nnbd_mixed/member_inheritance_from_opt_out.dart.weak.transformed.expect
index 3f07aa4..a1b69ec 100644
--- a/pkg/front_end/testcases/nnbd_mixed/member_inheritance_from_opt_out.dart.weak.transformed.expect
+++ b/pkg/front_end/testcases/nnbd_mixed/member_inheritance_from_opt_out.dart.weak.transformed.expect
@@ -49,22 +49,6 @@
   synthetic constructor •() → self::Class2a
     : super opt::LegacyClass::•()
     ;
-  abstract member-signature method method1() → core::int; -> opt::LegacyClass::method1
-  abstract member-signature method method2() → core::int?; -> opt::LegacyClass::method2
-  abstract member-signature method method3a(core::int a, core::int b) → core::int; -> opt::LegacyClass::method3a
-  abstract member-signature method method3b(core::int a, [core::int b = #C1]) → core::int; -> opt::LegacyClass::method3b
-  abstract member-signature method method3c([core::int a = #C1, core::int b = #C1]) → core::int; -> opt::LegacyClass::method3c
-  abstract member-signature method method4a(core::int? a, core::int? b) → core::int?; -> opt::LegacyClass::method4a
-  abstract member-signature method method4b(core::int? a, [core::int? b = #C1]) → core::int?; -> opt::LegacyClass::method4b
-  abstract member-signature method method4c([core::int? a = #C1, core::int? b = #C1]) → core::int?; -> opt::LegacyClass::method4c
-  abstract member-signature method method5a(core::int a, {core::int b = #C1}) → core::int; -> opt::LegacyClass::method5a
-  abstract member-signature method method5b({core::int a = #C1, core::int b = #C1}) → core::int; -> opt::LegacyClass::method5b
-  abstract member-signature method method5c({core::int a = #C1, core::int b = #C1}) → core::int; -> opt::LegacyClass::method5c
-  abstract member-signature method method6a(core::int? a, {core::int? b = #C1}) → core::int?; -> opt::LegacyClass::method6a
-  abstract member-signature method method6b({core::int? a = #C1, core::int? b = #C1}) → core::int?; -> opt::LegacyClass::method6b
-  abstract member-signature method method6c({core::int? a = #C1, core::int? b = #C1}) → core::int?; -> opt::LegacyClass::method6c
-  abstract member-signature get getter1() → core::int; -> opt::LegacyClass::getter1
-  abstract member-signature get getter2() → core::int?; -> opt::LegacyClass::getter2
   abstract member-signature get field1() → core::int; -> opt::LegacyClass::field1
   abstract member-signature set field1(core::int _) → void; -> opt::LegacyClass::field1
   abstract member-signature get field2() → core::int?; -> opt::LegacyClass::field2
@@ -81,6 +65,22 @@
   abstract member-signature set property3(core::int value) → void; -> opt::LegacyClass::property3
   abstract member-signature get property4() → core::int?; -> opt::LegacyClass::property4
   abstract member-signature set property4(core::int? value) → void; -> opt::LegacyClass::property4
+  abstract member-signature method method1() → core::int; -> opt::LegacyClass::method1
+  abstract member-signature method method2() → core::int?; -> opt::LegacyClass::method2
+  abstract member-signature method method3a(core::int a, core::int b) → core::int; -> opt::LegacyClass::method3a
+  abstract member-signature method method3b(core::int a, [core::int b = #C1]) → core::int; -> opt::LegacyClass::method3b
+  abstract member-signature method method3c([core::int a = #C1, core::int b = #C1]) → core::int; -> opt::LegacyClass::method3c
+  abstract member-signature method method4a(core::int? a, core::int? b) → core::int?; -> opt::LegacyClass::method4a
+  abstract member-signature method method4b(core::int? a, [core::int? b = #C1]) → core::int?; -> opt::LegacyClass::method4b
+  abstract member-signature method method4c([core::int? a = #C1, core::int? b = #C1]) → core::int?; -> opt::LegacyClass::method4c
+  abstract member-signature method method5a(core::int a, {core::int b = #C1}) → core::int; -> opt::LegacyClass::method5a
+  abstract member-signature method method5b({core::int a = #C1, core::int b = #C1}) → core::int; -> opt::LegacyClass::method5b
+  abstract member-signature method method5c({core::int a = #C1, core::int b = #C1}) → core::int; -> opt::LegacyClass::method5c
+  abstract member-signature method method6a(core::int? a, {core::int? b = #C1}) → core::int?; -> opt::LegacyClass::method6a
+  abstract member-signature method method6b({core::int? a = #C1, core::int? b = #C1}) → core::int?; -> opt::LegacyClass::method6b
+  abstract member-signature method method6c({core::int? a = #C1, core::int? b = #C1}) → core::int?; -> opt::LegacyClass::method6c
+  abstract member-signature get getter1() → core::int; -> opt::LegacyClass::getter1
+  abstract member-signature get getter2() → core::int?; -> opt::LegacyClass::getter2
   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
diff --git a/pkg/front_end/testcases/nnbd_mixed/mock_http_headers.dart.weak.expect b/pkg/front_end/testcases/nnbd_mixed/mock_http_headers.dart.weak.expect
index 831000c..225ab3c 100644
--- a/pkg/front_end/testcases/nnbd_mixed/mock_http_headers.dart.weak.expect
+++ b/pkg/front_end/testcases/nnbd_mixed/mock_http_headers.dart.weak.expect
@@ -25,94 +25,94 @@
   synthetic constructor •() → self::MockHttpHeaders*
     : super self::Mock::•()
     ;
-  no-such-method-forwarder operator [](core::String* name) → core::List<core::String*>*
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C1, 0, #C2, core::List::unmodifiable<dynamic>(<dynamic>[name]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4))) as{TypeError,ForDynamic} core::List<core::String*>*;
-  no-such-method-forwarder method value(core::String* name) → core::String*
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C5, 0, #C2, core::List::unmodifiable<dynamic>(<dynamic>[name]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4))) as{TypeError,ForDynamic} core::String*;
-  no-such-method-forwarder method add(core::String* name, core::Object* value, {core::bool* preserveHeaderCase = #C6}) → void
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C7, 0, #C2, core::List::unmodifiable<dynamic>(<dynamic>[name, value]), core::Map::unmodifiable<core::Symbol*, dynamic>(<core::Symbol*, dynamic>{#C8: preserveHeaderCase})));
-  no-such-method-forwarder method set(core::String* name, core::Object* value, {core::bool* preserveHeaderCase = #C6}) → void
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C9, 0, #C2, core::List::unmodifiable<dynamic>(<dynamic>[name, value]), core::Map::unmodifiable<core::Symbol*, dynamic>(<core::Symbol*, dynamic>{#C8: preserveHeaderCase})));
-  no-such-method-forwarder method remove(core::String* name, core::Object* value) → void
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C10, 0, #C2, core::List::unmodifiable<dynamic>(<dynamic>[name, value]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
-  no-such-method-forwarder method removeAll(core::String* name) → void
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C11, 0, #C2, core::List::unmodifiable<dynamic>(<dynamic>[name]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
-  no-such-method-forwarder method forEach((core::String*, core::List<core::String*>*) →* void action) → void
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C12, 0, #C2, core::List::unmodifiable<dynamic>(<dynamic>[action]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
-  no-such-method-forwarder method noFolding(core::String* name) → void
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C13, 0, #C2, core::List::unmodifiable<dynamic>(<dynamic>[name]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
   no-such-method-forwarder get date() → core::DateTime*
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C14, 1, #C2, #C3, core::Map::unmodifiable<core::Symbol*, dynamic>(#C4))) as{TypeError,ForDynamic} core::DateTime*;
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C1, 1, #C2, #C3, core::Map::unmodifiable<core::Symbol*, dynamic>(#C4))) as{TypeError,ForDynamic} core::DateTime*;
   no-such-method-forwarder set date(core::DateTime* _) → void
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C15, 2, #C2, core::List::unmodifiable<dynamic>(<dynamic>[_]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C5, 2, #C2, core::List::unmodifiable<dynamic>(<dynamic>[_]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
   no-such-method-forwarder get expires() → core::DateTime*
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C16, 1, #C2, #C3, core::Map::unmodifiable<core::Symbol*, dynamic>(#C4))) as{TypeError,ForDynamic} core::DateTime*;
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C6, 1, #C2, #C3, core::Map::unmodifiable<core::Symbol*, dynamic>(#C4))) as{TypeError,ForDynamic} core::DateTime*;
   no-such-method-forwarder set expires(core::DateTime* _) → void
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C17, 2, #C2, core::List::unmodifiable<dynamic>(<dynamic>[_]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C7, 2, #C2, core::List::unmodifiable<dynamic>(<dynamic>[_]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
   no-such-method-forwarder get ifModifiedSince() → core::DateTime*
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C18, 1, #C2, #C3, core::Map::unmodifiable<core::Symbol*, dynamic>(#C4))) as{TypeError,ForDynamic} core::DateTime*;
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C8, 1, #C2, #C3, core::Map::unmodifiable<core::Symbol*, dynamic>(#C4))) as{TypeError,ForDynamic} core::DateTime*;
   no-such-method-forwarder set ifModifiedSince(core::DateTime* _) → void
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C19, 2, #C2, core::List::unmodifiable<dynamic>(<dynamic>[_]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C9, 2, #C2, core::List::unmodifiable<dynamic>(<dynamic>[_]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
   no-such-method-forwarder get host() → core::String*
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C20, 1, #C2, #C3, core::Map::unmodifiable<core::Symbol*, dynamic>(#C4))) as{TypeError,ForDynamic} core::String*;
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C10, 1, #C2, #C3, core::Map::unmodifiable<core::Symbol*, dynamic>(#C4))) as{TypeError,ForDynamic} core::String*;
   no-such-method-forwarder set host(core::String* _) → void
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C21, 2, #C2, core::List::unmodifiable<dynamic>(<dynamic>[_]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C11, 2, #C2, core::List::unmodifiable<dynamic>(<dynamic>[_]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
   no-such-method-forwarder get port() → core::int*
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C22, 1, #C2, #C3, core::Map::unmodifiable<core::Symbol*, dynamic>(#C4))) as{TypeError,ForDynamic} core::int*;
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C12, 1, #C2, #C3, core::Map::unmodifiable<core::Symbol*, dynamic>(#C4))) as{TypeError,ForDynamic} core::int*;
   no-such-method-forwarder set port(core::int* _) → void
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C23, 2, #C2, core::List::unmodifiable<dynamic>(<dynamic>[_]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C13, 2, #C2, core::List::unmodifiable<dynamic>(<dynamic>[_]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
   no-such-method-forwarder get contentType() → _ht::ContentType*
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C24, 1, #C2, #C3, core::Map::unmodifiable<core::Symbol*, dynamic>(#C4))) as{TypeError,ForDynamic} _ht::ContentType*;
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C14, 1, #C2, #C3, core::Map::unmodifiable<core::Symbol*, dynamic>(#C4))) as{TypeError,ForDynamic} _ht::ContentType*;
   no-such-method-forwarder set contentType(_ht::ContentType* _) → void
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C25, 2, #C2, core::List::unmodifiable<dynamic>(<dynamic>[_]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C15, 2, #C2, core::List::unmodifiable<dynamic>(<dynamic>[_]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
   no-such-method-forwarder get contentLength() → core::int*
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C26, 1, #C2, #C3, core::Map::unmodifiable<core::Symbol*, dynamic>(#C4))) as{TypeError,ForDynamic} core::int*;
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C16, 1, #C2, #C3, core::Map::unmodifiable<core::Symbol*, dynamic>(#C4))) as{TypeError,ForDynamic} core::int*;
   no-such-method-forwarder set contentLength(core::int* _) → void
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C27, 2, #C2, core::List::unmodifiable<dynamic>(<dynamic>[_]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C17, 2, #C2, core::List::unmodifiable<dynamic>(<dynamic>[_]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
   no-such-method-forwarder get persistentConnection() → core::bool*
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C28, 1, #C2, #C3, core::Map::unmodifiable<core::Symbol*, dynamic>(#C4))) as{TypeError,ForDynamic} core::bool*;
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C18, 1, #C2, #C3, core::Map::unmodifiable<core::Symbol*, dynamic>(#C4))) as{TypeError,ForDynamic} core::bool*;
   no-such-method-forwarder set persistentConnection(core::bool* _) → void
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C29, 2, #C2, core::List::unmodifiable<dynamic>(<dynamic>[_]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C19, 2, #C2, core::List::unmodifiable<dynamic>(<dynamic>[_]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
   no-such-method-forwarder get chunkedTransferEncoding() → core::bool*
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C30, 1, #C2, #C3, core::Map::unmodifiable<core::Symbol*, dynamic>(#C4))) as{TypeError,ForDynamic} core::bool*;
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C20, 1, #C2, #C3, core::Map::unmodifiable<core::Symbol*, dynamic>(#C4))) as{TypeError,ForDynamic} core::bool*;
   no-such-method-forwarder set chunkedTransferEncoding(core::bool* _) → void
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C31, 2, #C2, core::List::unmodifiable<dynamic>(<dynamic>[_]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C21, 2, #C2, core::List::unmodifiable<dynamic>(<dynamic>[_]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
+  no-such-method-forwarder operator [](core::String* name) → core::List<core::String*>*
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C22, 0, #C2, core::List::unmodifiable<dynamic>(<dynamic>[name]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4))) as{TypeError,ForDynamic} core::List<core::String*>*;
+  no-such-method-forwarder method value(core::String* name) → core::String*
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C23, 0, #C2, core::List::unmodifiable<dynamic>(<dynamic>[name]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4))) as{TypeError,ForDynamic} core::String*;
+  no-such-method-forwarder method add(core::String* name, core::Object* value, {core::bool* preserveHeaderCase = #C24}) → void
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C25, 0, #C2, core::List::unmodifiable<dynamic>(<dynamic>[name, value]), core::Map::unmodifiable<core::Symbol*, dynamic>(<core::Symbol*, dynamic>{#C26: preserveHeaderCase})));
+  no-such-method-forwarder method set(core::String* name, core::Object* value, {core::bool* preserveHeaderCase = #C24}) → void
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C27, 0, #C2, core::List::unmodifiable<dynamic>(<dynamic>[name, value]), core::Map::unmodifiable<core::Symbol*, dynamic>(<core::Symbol*, dynamic>{#C26: preserveHeaderCase})));
+  no-such-method-forwarder method remove(core::String* name, core::Object* value) → void
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C28, 0, #C2, core::List::unmodifiable<dynamic>(<dynamic>[name, value]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
+  no-such-method-forwarder method removeAll(core::String* name) → void
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C29, 0, #C2, core::List::unmodifiable<dynamic>(<dynamic>[name]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
+  no-such-method-forwarder method forEach((core::String*, core::List<core::String*>*) →* void action) → void
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C30, 0, #C2, core::List::unmodifiable<dynamic>(<dynamic>[action]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
+  no-such-method-forwarder method noFolding(core::String* name) → void
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C31, 0, #C2, core::List::unmodifiable<dynamic>(<dynamic>[name]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
   no-such-method-forwarder method /*isNonNullableByDefault, from org-dartlang-sdk:///sdk/lib/_http/http.dart */ clear() → void
     return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C32, 0, #C2, #C3, core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
 }
 static method main() → dynamic {}
 
 constants  {
-  #C1 = #[]
+  #C1 = #date
   #C2 = <core::Type*>[]
   #C3 = <dynamic>[]
   #C4 = core::_ImmutableMap<core::Symbol*, dynamic> {_kvPairs:#C3}
-  #C5 = #value
-  #C6 = false
-  #C7 = #add
-  #C8 = #preserveHeaderCase
-  #C9 = #set
-  #C10 = #remove
-  #C11 = #removeAll
-  #C12 = #forEach
-  #C13 = #noFolding
-  #C14 = #date
-  #C15 = #date=
-  #C16 = #expires
-  #C17 = #expires=
-  #C18 = #ifModifiedSince
-  #C19 = #ifModifiedSince=
-  #C20 = #host
-  #C21 = #host=
-  #C22 = #port
-  #C23 = #port=
-  #C24 = #contentType
-  #C25 = #contentType=
-  #C26 = #contentLength
-  #C27 = #contentLength=
-  #C28 = #persistentConnection
-  #C29 = #persistentConnection=
-  #C30 = #chunkedTransferEncoding
-  #C31 = #chunkedTransferEncoding=
+  #C5 = #date=
+  #C6 = #expires
+  #C7 = #expires=
+  #C8 = #ifModifiedSince
+  #C9 = #ifModifiedSince=
+  #C10 = #host
+  #C11 = #host=
+  #C12 = #port
+  #C13 = #port=
+  #C14 = #contentType
+  #C15 = #contentType=
+  #C16 = #contentLength
+  #C17 = #contentLength=
+  #C18 = #persistentConnection
+  #C19 = #persistentConnection=
+  #C20 = #chunkedTransferEncoding
+  #C21 = #chunkedTransferEncoding=
+  #C22 = #[]
+  #C23 = #value
+  #C24 = false
+  #C25 = #add
+  #C26 = #preserveHeaderCase
+  #C27 = #set
+  #C28 = #remove
+  #C29 = #removeAll
+  #C30 = #forEach
+  #C31 = #noFolding
   #C32 = #clear
 }
diff --git a/pkg/front_end/testcases/nnbd_mixed/mock_http_headers.dart.weak.transformed.expect b/pkg/front_end/testcases/nnbd_mixed/mock_http_headers.dart.weak.transformed.expect
index 831000c..225ab3c 100644
--- a/pkg/front_end/testcases/nnbd_mixed/mock_http_headers.dart.weak.transformed.expect
+++ b/pkg/front_end/testcases/nnbd_mixed/mock_http_headers.dart.weak.transformed.expect
@@ -25,94 +25,94 @@
   synthetic constructor •() → self::MockHttpHeaders*
     : super self::Mock::•()
     ;
-  no-such-method-forwarder operator [](core::String* name) → core::List<core::String*>*
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C1, 0, #C2, core::List::unmodifiable<dynamic>(<dynamic>[name]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4))) as{TypeError,ForDynamic} core::List<core::String*>*;
-  no-such-method-forwarder method value(core::String* name) → core::String*
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C5, 0, #C2, core::List::unmodifiable<dynamic>(<dynamic>[name]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4))) as{TypeError,ForDynamic} core::String*;
-  no-such-method-forwarder method add(core::String* name, core::Object* value, {core::bool* preserveHeaderCase = #C6}) → void
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C7, 0, #C2, core::List::unmodifiable<dynamic>(<dynamic>[name, value]), core::Map::unmodifiable<core::Symbol*, dynamic>(<core::Symbol*, dynamic>{#C8: preserveHeaderCase})));
-  no-such-method-forwarder method set(core::String* name, core::Object* value, {core::bool* preserveHeaderCase = #C6}) → void
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C9, 0, #C2, core::List::unmodifiable<dynamic>(<dynamic>[name, value]), core::Map::unmodifiable<core::Symbol*, dynamic>(<core::Symbol*, dynamic>{#C8: preserveHeaderCase})));
-  no-such-method-forwarder method remove(core::String* name, core::Object* value) → void
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C10, 0, #C2, core::List::unmodifiable<dynamic>(<dynamic>[name, value]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
-  no-such-method-forwarder method removeAll(core::String* name) → void
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C11, 0, #C2, core::List::unmodifiable<dynamic>(<dynamic>[name]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
-  no-such-method-forwarder method forEach((core::String*, core::List<core::String*>*) →* void action) → void
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C12, 0, #C2, core::List::unmodifiable<dynamic>(<dynamic>[action]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
-  no-such-method-forwarder method noFolding(core::String* name) → void
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C13, 0, #C2, core::List::unmodifiable<dynamic>(<dynamic>[name]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
   no-such-method-forwarder get date() → core::DateTime*
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C14, 1, #C2, #C3, core::Map::unmodifiable<core::Symbol*, dynamic>(#C4))) as{TypeError,ForDynamic} core::DateTime*;
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C1, 1, #C2, #C3, core::Map::unmodifiable<core::Symbol*, dynamic>(#C4))) as{TypeError,ForDynamic} core::DateTime*;
   no-such-method-forwarder set date(core::DateTime* _) → void
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C15, 2, #C2, core::List::unmodifiable<dynamic>(<dynamic>[_]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C5, 2, #C2, core::List::unmodifiable<dynamic>(<dynamic>[_]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
   no-such-method-forwarder get expires() → core::DateTime*
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C16, 1, #C2, #C3, core::Map::unmodifiable<core::Symbol*, dynamic>(#C4))) as{TypeError,ForDynamic} core::DateTime*;
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C6, 1, #C2, #C3, core::Map::unmodifiable<core::Symbol*, dynamic>(#C4))) as{TypeError,ForDynamic} core::DateTime*;
   no-such-method-forwarder set expires(core::DateTime* _) → void
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C17, 2, #C2, core::List::unmodifiable<dynamic>(<dynamic>[_]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C7, 2, #C2, core::List::unmodifiable<dynamic>(<dynamic>[_]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
   no-such-method-forwarder get ifModifiedSince() → core::DateTime*
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C18, 1, #C2, #C3, core::Map::unmodifiable<core::Symbol*, dynamic>(#C4))) as{TypeError,ForDynamic} core::DateTime*;
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C8, 1, #C2, #C3, core::Map::unmodifiable<core::Symbol*, dynamic>(#C4))) as{TypeError,ForDynamic} core::DateTime*;
   no-such-method-forwarder set ifModifiedSince(core::DateTime* _) → void
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C19, 2, #C2, core::List::unmodifiable<dynamic>(<dynamic>[_]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C9, 2, #C2, core::List::unmodifiable<dynamic>(<dynamic>[_]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
   no-such-method-forwarder get host() → core::String*
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C20, 1, #C2, #C3, core::Map::unmodifiable<core::Symbol*, dynamic>(#C4))) as{TypeError,ForDynamic} core::String*;
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C10, 1, #C2, #C3, core::Map::unmodifiable<core::Symbol*, dynamic>(#C4))) as{TypeError,ForDynamic} core::String*;
   no-such-method-forwarder set host(core::String* _) → void
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C21, 2, #C2, core::List::unmodifiable<dynamic>(<dynamic>[_]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C11, 2, #C2, core::List::unmodifiable<dynamic>(<dynamic>[_]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
   no-such-method-forwarder get port() → core::int*
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C22, 1, #C2, #C3, core::Map::unmodifiable<core::Symbol*, dynamic>(#C4))) as{TypeError,ForDynamic} core::int*;
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C12, 1, #C2, #C3, core::Map::unmodifiable<core::Symbol*, dynamic>(#C4))) as{TypeError,ForDynamic} core::int*;
   no-such-method-forwarder set port(core::int* _) → void
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C23, 2, #C2, core::List::unmodifiable<dynamic>(<dynamic>[_]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C13, 2, #C2, core::List::unmodifiable<dynamic>(<dynamic>[_]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
   no-such-method-forwarder get contentType() → _ht::ContentType*
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C24, 1, #C2, #C3, core::Map::unmodifiable<core::Symbol*, dynamic>(#C4))) as{TypeError,ForDynamic} _ht::ContentType*;
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C14, 1, #C2, #C3, core::Map::unmodifiable<core::Symbol*, dynamic>(#C4))) as{TypeError,ForDynamic} _ht::ContentType*;
   no-such-method-forwarder set contentType(_ht::ContentType* _) → void
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C25, 2, #C2, core::List::unmodifiable<dynamic>(<dynamic>[_]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C15, 2, #C2, core::List::unmodifiable<dynamic>(<dynamic>[_]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
   no-such-method-forwarder get contentLength() → core::int*
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C26, 1, #C2, #C3, core::Map::unmodifiable<core::Symbol*, dynamic>(#C4))) as{TypeError,ForDynamic} core::int*;
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C16, 1, #C2, #C3, core::Map::unmodifiable<core::Symbol*, dynamic>(#C4))) as{TypeError,ForDynamic} core::int*;
   no-such-method-forwarder set contentLength(core::int* _) → void
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C27, 2, #C2, core::List::unmodifiable<dynamic>(<dynamic>[_]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C17, 2, #C2, core::List::unmodifiable<dynamic>(<dynamic>[_]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
   no-such-method-forwarder get persistentConnection() → core::bool*
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C28, 1, #C2, #C3, core::Map::unmodifiable<core::Symbol*, dynamic>(#C4))) as{TypeError,ForDynamic} core::bool*;
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C18, 1, #C2, #C3, core::Map::unmodifiable<core::Symbol*, dynamic>(#C4))) as{TypeError,ForDynamic} core::bool*;
   no-such-method-forwarder set persistentConnection(core::bool* _) → void
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C29, 2, #C2, core::List::unmodifiable<dynamic>(<dynamic>[_]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C19, 2, #C2, core::List::unmodifiable<dynamic>(<dynamic>[_]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
   no-such-method-forwarder get chunkedTransferEncoding() → core::bool*
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C30, 1, #C2, #C3, core::Map::unmodifiable<core::Symbol*, dynamic>(#C4))) as{TypeError,ForDynamic} core::bool*;
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C20, 1, #C2, #C3, core::Map::unmodifiable<core::Symbol*, dynamic>(#C4))) as{TypeError,ForDynamic} core::bool*;
   no-such-method-forwarder set chunkedTransferEncoding(core::bool* _) → void
-    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C31, 2, #C2, core::List::unmodifiable<dynamic>(<dynamic>[_]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C21, 2, #C2, core::List::unmodifiable<dynamic>(<dynamic>[_]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
+  no-such-method-forwarder operator [](core::String* name) → core::List<core::String*>*
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C22, 0, #C2, core::List::unmodifiable<dynamic>(<dynamic>[name]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4))) as{TypeError,ForDynamic} core::List<core::String*>*;
+  no-such-method-forwarder method value(core::String* name) → core::String*
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C23, 0, #C2, core::List::unmodifiable<dynamic>(<dynamic>[name]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4))) as{TypeError,ForDynamic} core::String*;
+  no-such-method-forwarder method add(core::String* name, core::Object* value, {core::bool* preserveHeaderCase = #C24}) → void
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C25, 0, #C2, core::List::unmodifiable<dynamic>(<dynamic>[name, value]), core::Map::unmodifiable<core::Symbol*, dynamic>(<core::Symbol*, dynamic>{#C26: preserveHeaderCase})));
+  no-such-method-forwarder method set(core::String* name, core::Object* value, {core::bool* preserveHeaderCase = #C24}) → void
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C27, 0, #C2, core::List::unmodifiable<dynamic>(<dynamic>[name, value]), core::Map::unmodifiable<core::Symbol*, dynamic>(<core::Symbol*, dynamic>{#C26: preserveHeaderCase})));
+  no-such-method-forwarder method remove(core::String* name, core::Object* value) → void
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C28, 0, #C2, core::List::unmodifiable<dynamic>(<dynamic>[name, value]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
+  no-such-method-forwarder method removeAll(core::String* name) → void
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C29, 0, #C2, core::List::unmodifiable<dynamic>(<dynamic>[name]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
+  no-such-method-forwarder method forEach((core::String*, core::List<core::String*>*) →* void action) → void
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C30, 0, #C2, core::List::unmodifiable<dynamic>(<dynamic>[action]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
+  no-such-method-forwarder method noFolding(core::String* name) → void
+    return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C31, 0, #C2, core::List::unmodifiable<dynamic>(<dynamic>[name]), core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
   no-such-method-forwarder method /*isNonNullableByDefault, from org-dartlang-sdk:///sdk/lib/_http/http.dart */ clear() → void
     return this.{self::Mock::noSuchMethod}(new core::_InvocationMirror::_withType(#C32, 0, #C2, #C3, core::Map::unmodifiable<core::Symbol*, dynamic>(#C4)));
 }
 static method main() → dynamic {}
 
 constants  {
-  #C1 = #[]
+  #C1 = #date
   #C2 = <core::Type*>[]
   #C3 = <dynamic>[]
   #C4 = core::_ImmutableMap<core::Symbol*, dynamic> {_kvPairs:#C3}
-  #C5 = #value
-  #C6 = false
-  #C7 = #add
-  #C8 = #preserveHeaderCase
-  #C9 = #set
-  #C10 = #remove
-  #C11 = #removeAll
-  #C12 = #forEach
-  #C13 = #noFolding
-  #C14 = #date
-  #C15 = #date=
-  #C16 = #expires
-  #C17 = #expires=
-  #C18 = #ifModifiedSince
-  #C19 = #ifModifiedSince=
-  #C20 = #host
-  #C21 = #host=
-  #C22 = #port
-  #C23 = #port=
-  #C24 = #contentType
-  #C25 = #contentType=
-  #C26 = #contentLength
-  #C27 = #contentLength=
-  #C28 = #persistentConnection
-  #C29 = #persistentConnection=
-  #C30 = #chunkedTransferEncoding
-  #C31 = #chunkedTransferEncoding=
+  #C5 = #date=
+  #C6 = #expires
+  #C7 = #expires=
+  #C8 = #ifModifiedSince
+  #C9 = #ifModifiedSince=
+  #C10 = #host
+  #C11 = #host=
+  #C12 = #port
+  #C13 = #port=
+  #C14 = #contentType
+  #C15 = #contentType=
+  #C16 = #contentLength
+  #C17 = #contentLength=
+  #C18 = #persistentConnection
+  #C19 = #persistentConnection=
+  #C20 = #chunkedTransferEncoding
+  #C21 = #chunkedTransferEncoding=
+  #C22 = #[]
+  #C23 = #value
+  #C24 = false
+  #C25 = #add
+  #C26 = #preserveHeaderCase
+  #C27 = #set
+  #C28 = #remove
+  #C29 = #removeAll
+  #C30 = #forEach
+  #C31 = #noFolding
   #C32 = #clear
 }
diff --git a/pkg/front_end/testcases/old_dills/dills/dart2js.version.46.compile.1.dill b/pkg/front_end/testcases/old_dills/dills/dart2js.version.46.compile.1.dill
new file mode 100644
index 0000000..d766ad5
--- /dev/null
+++ b/pkg/front_end/testcases/old_dills/dills/dart2js.version.46.compile.1.dill
Binary files differ
diff --git a/pkg/front_end/testcases/outline.status b/pkg/front_end/testcases/outline.status
index 82835d3..532869a 100644
--- a/pkg/front_end/testcases/outline.status
+++ b/pkg/front_end/testcases/outline.status
@@ -16,6 +16,7 @@
 general/bug30695: TypeCheckError
 general/constants/const_collections: TypeCheckError
 general/covariant_field: TypeCheckError
+general/getter_vs_setter_type: TypeCheckError
 general/infer_field_from_multiple: TypeCheckError
 general/invalid_operator: TypeCheckError
 general/invalid_operator_override: TypeCheckError
@@ -44,6 +45,7 @@
 inference/mixin_inference_unification_2: TypeCheckError
 late_lowering/covariant_late_field: TypeCheckError
 nnbd/covariant_late_field: TypeCheckError
+nnbd/getter_vs_setter_type: TypeCheckError
 nnbd/issue42603: TypeCheckError
 rasta/native_is_illegal: Pass # Issue 29763
 runtime_checks_new/mixin_forwarding_stub_field: TypeCheckError
diff --git a/pkg/front_end/testcases/runtime_checks_new/contravariant_generic_return_with_compound_assign_implicit_downcast.dart.outline.expect b/pkg/front_end/testcases/runtime_checks_new/contravariant_generic_return_with_compound_assign_implicit_downcast.dart.outline.expect
index 5fd91f2..fa1259d 100644
--- a/pkg/front_end/testcases/runtime_checks_new/contravariant_generic_return_with_compound_assign_implicit_downcast.dart.outline.expect
+++ b/pkg/front_end/testcases/runtime_checks_new/contravariant_generic_return_with_compound_assign_implicit_downcast.dart.outline.expect
@@ -1,4 +1,15 @@
 library test;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/runtime_checks_new/contravariant_generic_return_with_compound_assign_implicit_downcast.dart:30:14: Error: The type 'C<num>' of the getter 'D.value' is not assignable to the type 'int Function(int)' of the setter 'D.value'.
+//  - 'C' is from 'pkg/front_end/testcases/runtime_checks_new/contravariant_generic_return_with_compound_assign_implicit_downcast.dart'.
+//   C<num> get value => getValue;
+//              ^^^^^
+// pkg/front_end/testcases/runtime_checks_new/contravariant_generic_return_with_compound_assign_implicit_downcast.dart:32:12: Context: This is the declaration of the setter 'D.value'.
+//   void set value(int Function(int) value) {
+//            ^^^^^
+//
 import self as self;
 import "dart:core" as core;
 
diff --git a/pkg/front_end/testcases/runtime_checks_new/contravariant_generic_return_with_compound_assign_implicit_downcast.dart.strong.expect b/pkg/front_end/testcases/runtime_checks_new/contravariant_generic_return_with_compound_assign_implicit_downcast.dart.strong.expect
index 59b4ef8..408ea27 100644
--- a/pkg/front_end/testcases/runtime_checks_new/contravariant_generic_return_with_compound_assign_implicit_downcast.dart.strong.expect
+++ b/pkg/front_end/testcases/runtime_checks_new/contravariant_generic_return_with_compound_assign_implicit_downcast.dart.strong.expect
@@ -2,6 +2,14 @@
 //
 // Problems in library:
 //
+// pkg/front_end/testcases/runtime_checks_new/contravariant_generic_return_with_compound_assign_implicit_downcast.dart:30:14: Error: The type 'C<num>' of the getter 'D.value' is not assignable to the type 'int Function(int)' of the setter 'D.value'.
+//  - 'C' is from 'pkg/front_end/testcases/runtime_checks_new/contravariant_generic_return_with_compound_assign_implicit_downcast.dart'.
+//   C<num> get value => getValue;
+//              ^^^^^
+// pkg/front_end/testcases/runtime_checks_new/contravariant_generic_return_with_compound_assign_implicit_downcast.dart:32:12: Context: This is the declaration of the setter 'D.value'.
+//   void set value(int Function(int) value) {
+//            ^^^^^
+//
 // pkg/front_end/testcases/runtime_checks_new/contravariant_generic_return_with_compound_assign_implicit_downcast.dart:49:46: Error: A value of type 'num Function(num)' can't be assigned to a variable of type 'int Function(int)'.
 //   d.value /*@ checkReturn=(num*) ->* num* */ += 1;
 //                                              ^
diff --git a/pkg/front_end/testcases/runtime_checks_new/contravariant_generic_return_with_compound_assign_implicit_downcast.dart.strong.transformed.expect b/pkg/front_end/testcases/runtime_checks_new/contravariant_generic_return_with_compound_assign_implicit_downcast.dart.strong.transformed.expect
index c4d3d9c..7907879 100644
--- a/pkg/front_end/testcases/runtime_checks_new/contravariant_generic_return_with_compound_assign_implicit_downcast.dart.strong.transformed.expect
+++ b/pkg/front_end/testcases/runtime_checks_new/contravariant_generic_return_with_compound_assign_implicit_downcast.dart.strong.transformed.expect
@@ -2,6 +2,14 @@
 //
 // Problems in library:
 //
+// pkg/front_end/testcases/runtime_checks_new/contravariant_generic_return_with_compound_assign_implicit_downcast.dart:30:14: Error: The type 'C<num>' of the getter 'D.value' is not assignable to the type 'int Function(int)' of the setter 'D.value'.
+//  - 'C' is from 'pkg/front_end/testcases/runtime_checks_new/contravariant_generic_return_with_compound_assign_implicit_downcast.dart'.
+//   C<num> get value => getValue;
+//              ^^^^^
+// pkg/front_end/testcases/runtime_checks_new/contravariant_generic_return_with_compound_assign_implicit_downcast.dart:32:12: Context: This is the declaration of the setter 'D.value'.
+//   void set value(int Function(int) value) {
+//            ^^^^^
+//
 // pkg/front_end/testcases/runtime_checks_new/contravariant_generic_return_with_compound_assign_implicit_downcast.dart:49:46: Error: A value of type 'num Function(num)' can't be assigned to a variable of type 'int Function(int)'.
 //   d.value /*@ checkReturn=(num*) ->* num* */ += 1;
 //                                              ^
diff --git a/pkg/front_end/testcases/strong.status b/pkg/front_end/testcases/strong.status
index 660c22a..64c777e 100644
--- a/pkg/front_end/testcases/strong.status
+++ b/pkg/front_end/testcases/strong.status
@@ -62,6 +62,7 @@
 general/error_recovery/yield_not_in_generator: RuntimeError
 general/expressions: RuntimeError
 general/external_import: RuntimeError # The native extension to import doesn't exist. This is ok.
+general/getter_vs_setter_type: TypeCheckError
 general/incomplete_field_formal_parameter: RuntimeError
 general/infer_field_from_multiple: TypeCheckError
 general/invalid_operator: TypeCheckError
@@ -174,6 +175,7 @@
 late_lowering/initializer_rewrite_from_opt_out: RuntimeError # Test is inherently mixed mode
 late_lowering/non_nullable_from_opt_out: RuntimeError # Test is inherently mixed mode
 nnbd/covariant_late_field: TypeCheckError
+nnbd/getter_vs_setter_type: TypeCheckError
 nnbd/issue41180: RuntimeError # Strong mode runtime checking fails due to mixed strong mode.
 nnbd/issue42546: TypeCheckError
 nnbd/issue42603: TypeCheckError
diff --git a/pkg/front_end/testcases/text_serialization.status b/pkg/front_end/testcases/text_serialization.status
index 5515dcd..be9e404 100644
--- a/pkg/front_end/testcases/text_serialization.status
+++ b/pkg/front_end/testcases/text_serialization.status
@@ -66,6 +66,7 @@
 general/error_recovery/yield_not_in_generator: RuntimeError
 general/expressions: RuntimeError
 general/external_import: RuntimeError
+general/getter_vs_setter_type: TypeCheckError
 general/incomplete_field_formal_parameter: RuntimeError
 general/infer_field_from_multiple: TypeCheckError
 general/invalid_operator: TypeCheckError
@@ -176,6 +177,7 @@
 late_lowering/initializer_rewrite_from_opt_out: RuntimeError # Test is inherently mixed mode
 late_lowering/non_nullable_from_opt_out: RuntimeError # Test is inherently mixed mode
 nnbd/covariant_late_field: TypeCheckError
+nnbd/getter_vs_setter_type: TypeCheckError
 nnbd/issue41180: RuntimeError
 nnbd/issue42546: TypeCheckError
 nnbd/issue42603: TypeCheckError
diff --git a/pkg/front_end/testcases/textual_outline.status b/pkg/front_end/testcases/textual_outline.status
index 3d0f6a4..d26a0c2 100644
--- a/pkg/front_end/testcases/textual_outline.status
+++ b/pkg/front_end/testcases/textual_outline.status
@@ -132,6 +132,7 @@
 inference/unsafe_block_closure_inference_function_call_explicit_dynamic_param_via_expr1: FormatterCrash
 inference/unsafe_block_closure_inference_function_call_explicit_type_param_via_expr1: FormatterCrash
 late_lowering/covariant_late_field: FormatterCrash
+late_lowering/getter_vs_setter_type: FormatterCrash
 late_lowering/infer_late_field_type: FormatterCrash
 late_lowering/initializer_rewrite: FormatterCrash
 late_lowering/initializer_rewrite_from_opt_out: FormatterCrash
@@ -170,6 +171,7 @@
 nnbd/external_field_errors: FormatterCrash
 nnbd/external_fields: FormatterCrash
 nnbd/forbidden_supers: FormatterCrash
+nnbd/getter_vs_setter_type_late: FormatterCrash
 nnbd/infer_if_null: FormatterCrash
 nnbd/inheritance_from_opt_in: FormatterCrash
 nnbd/issue40805: FormatterCrash
diff --git a/pkg/front_end/testcases/weak.status b/pkg/front_end/testcases/weak.status
index eae95b4..689551d 100644
--- a/pkg/front_end/testcases/weak.status
+++ b/pkg/front_end/testcases/weak.status
@@ -60,6 +60,7 @@
 general_nnbd_opt_out/void_methods: RuntimeError
 late_lowering/covariant_late_field: TypeCheckError
 nnbd/covariant_late_field: TypeCheckError
+nnbd/getter_vs_setter_type: TypeCheckError
 nnbd/issue42546: TypeCheckError
 nnbd/issue42603: TypeCheckError
 nnbd/no_support_for_old_null_aware_index_access_syntax: RuntimeError # Expected.
diff --git a/runtime/observatory/tests/service/service.status b/runtime/observatory/tests/service/service.status
index c16feab..bc2bb42 100644
--- a/runtime/observatory/tests/service/service.status
+++ b/runtime/observatory/tests/service/service.status
@@ -15,10 +15,8 @@
 [ $arch == arm ]
 process_service_test: Pass, Fail # Issue 24344
 
-# Test uses service API and relies on correct class names
 [ $builder_tag == obfuscated ]
-dominator_tree_vm_test: SkipByDesign
-dominator_tree_vm_with_double_field_test: SkipByDesign
+*: SkipByDesign # Responses full of obfuscated names
 
 # Tests with known analyzer issues
 [ $compiler == dart2analyzer ]
diff --git a/runtime/vm/clustered_snapshot.cc b/runtime/vm/clustered_snapshot.cc
index 0468cab..7fb5eca 100644
--- a/runtime/vm/clustered_snapshot.cc
+++ b/runtime/vm/clustered_snapshot.cc
@@ -5158,9 +5158,9 @@
 
 class ProgramSerializationRoots : public SerializationRoots {
  public:
-  ProgramSerializationRoots(intptr_t num_base_objects,
+  ProgramSerializationRoots(ZoneGrowableArray<Object*>* base_objects,
                             ObjectStore* object_store)
-      : num_base_objects_(num_base_objects),
+      : base_objects_(base_objects),
         object_store_(object_store),
         saved_symbol_table_(Array::Handle()),
         saved_canonical_types_(Array::Handle()),
@@ -5194,7 +5194,7 @@
   }
 
   void AddBaseObjects(Serializer* s) {
-    if (num_base_objects_ == 0) {
+    if (base_objects_ == nullptr) {
       // Not writing a new vm isolate: use the one this VM was loaded from.
       const Array& base_objects = Object::vm_isolate_snapshot_object_table();
       for (intptr_t i = kFirstReference; i < base_objects.Length(); i++) {
@@ -5202,7 +5202,9 @@
       }
     } else {
       // Base objects carried over from WriteVMSnapshot.
-      s->CarryOverBaseObjects(num_base_objects_);
+      for (intptr_t i = 0; i < base_objects_->length(); i++) {
+        s->AddBaseObject((*base_objects_)[i]->raw());
+      }
     }
   }
 
@@ -5242,7 +5244,7 @@
   }
 
  private:
-  intptr_t num_base_objects_;
+  ZoneGrowableArray<Object*>* base_objects_;
   ObjectStore* object_store_;
   Array& saved_symbol_table_;
   Array& saved_canonical_types_;
@@ -5306,9 +5308,10 @@
       : unit_(unit) {}
 
   void AddBaseObjects(Serializer* s) {
-    intptr_t num_base_objects = unit_->parent()->num_objects();
-    ASSERT(num_base_objects != 0);
-    s->CarryOverBaseObjects(num_base_objects);
+    ZoneGrowableArray<Object*>* objects = unit_->parent()->objects();
+    for (intptr_t i = 0; i < objects->length(); i++) {
+      s->AddBaseObject(objects->At(i)->raw());
+    }
   }
 
   void PushRoots(Serializer* s) {
@@ -5469,6 +5472,58 @@
   delete[] clusters_by_cid_;
 }
 
+void Serializer::AddBaseObject(ObjectPtr base_object,
+                               const char* type,
+                               const char* name) {
+  intptr_t ref = AssignRef(base_object);
+  num_base_objects_++;
+
+  if ((profile_writer_ != nullptr) && (type != nullptr)) {
+    if (name == nullptr) {
+      name = "<base object>";
+    }
+    profile_writer_->SetObjectTypeAndName(
+        {V8SnapshotProfileWriter::kSnapshot, ref}, type, name);
+    profile_writer_->AddRoot({V8SnapshotProfileWriter::kSnapshot, ref});
+  }
+}
+
+intptr_t Serializer::AssignRef(ObjectPtr object) {
+  ASSERT(IsAllocatedReference(next_ref_index_));
+  if (object->IsHeapObject()) {
+    // The object id weak table holds image offsets for Instructions instead
+    // of ref indices.
+    ASSERT(!object->IsInstructions());
+    heap_->SetObjectId(object, next_ref_index_);
+    ASSERT(heap_->GetObjectId(object) == next_ref_index_);
+  } else {
+    SmiPtr smi = Smi::RawCast(object);
+    SmiObjectIdPair* existing_pair = smi_ids_.Lookup(smi);
+    if (existing_pair != NULL) {
+      ASSERT(existing_pair->id_ == kUnallocatedReference);
+      existing_pair->id_ = next_ref_index_;
+    } else {
+      SmiObjectIdPair new_pair;
+      new_pair.smi_ = smi;
+      new_pair.id_ = next_ref_index_;
+      smi_ids_.Insert(new_pair);
+    }
+  }
+
+  objects_->Add(&Object::ZoneHandle(object));
+
+  return next_ref_index_++;
+}
+
+intptr_t Serializer::AssignArtificialRef(ObjectPtr object) {
+  ASSERT(object.IsHeapObject());
+  const intptr_t ref = -(next_ref_index_++);
+  ASSERT(IsArtificialReference(ref));
+  heap_->SetObjectId(object, ref);
+  ASSERT(heap_->GetObjectId(object) == ref);
+  return ref;
+}
+
 void Serializer::FlushBytesWrittenToRoot() {
 #if defined(DART_PRECOMPILER)
   if (profile_writer_ != nullptr) {
@@ -5999,7 +6054,7 @@
   }
 }
 
-intptr_t Serializer::Serialize(SerializationRoots* roots) {
+ZoneGrowableArray<Object*>* Serializer::Serialize(SerializationRoots* roots) {
   roots->AddBaseObjects(this);
 
   NoSafepointScope no_safepoint;
@@ -6065,12 +6120,8 @@
 
   // We should have assigned a ref to every object we pushed.
   ASSERT((next_ref_index_ - 1) == num_objects);
-
-  if (loading_units_ != nullptr) {
-    LoadingUnitSerializationData* unit =
-        (*loading_units_)[current_loading_unit_id_];
-    unit->set_num_objects(num_objects);
-  }
+  // And recorded them all in [objects_].
+  ASSERT(objects_->length() == num_objects);
 
 #if defined(DART_PRECOMPILER)
   // When writing snapshot profile, we want to retain some of the program
@@ -6106,12 +6157,8 @@
 
   PrintSnapshotSizes();
 
-  // Note we are not clearing the object id table. The full ref table
-  // of the vm isolate snapshot serves as the base objects for the
-  // regular isolate snapshot.
-
-  // Return the number of objects, -1 accounts for unused ref 0.
-  return next_ref_index_ - kFirstReference;
+  heap()->ResetObjectIdTable();
+  return objects_;
 }
 #endif  // !defined(DART_PRECOMPILED_RUNTIME)
 
@@ -6914,7 +6961,7 @@
 
 FullSnapshotWriter::~FullSnapshotWriter() {}
 
-intptr_t FullSnapshotWriter::WriteVMSnapshot() {
+ZoneGrowableArray<Object*>* FullSnapshotWriter::WriteVMSnapshot() {
   TIMELINE_DURATION(thread(), Isolate, "WriteVMSnapshot");
 
   ASSERT(vm_snapshot_data_ != nullptr);
@@ -6925,7 +6972,7 @@
   serializer.WriteVersionAndFeatures(true);
   VMSerializationRoots roots(
       Array::Handle(Dart::vm_isolate()->object_store()->symbol_table()));
-  intptr_t num_objects = serializer.Serialize(&roots);
+  ZoneGrowableArray<Object*>* objects = serializer.Serialize(&roots);
   serializer.FillHeader(serializer.kind());
   clustered_vm_size_ = serializer.bytes_written();
 
@@ -6940,11 +6987,11 @@
 
   // The clustered part + the direct mapped data part.
   vm_isolate_snapshot_size_ = serializer.bytes_written();
-  return num_objects;
+  return objects;
 }
 
 void FullSnapshotWriter::WriteProgramSnapshot(
-    intptr_t num_base_objects,
+    ZoneGrowableArray<Object*>* objects,
     GrowableArray<LoadingUnitSerializationData*>* units) {
   TIMELINE_DURATION(thread(), Isolate, "WriteProgramSnapshot");
 
@@ -6965,8 +7012,11 @@
 
   serializer.ReserveHeader();
   serializer.WriteVersionAndFeatures(false);
-  ProgramSerializationRoots roots(num_base_objects, object_store);
-  serializer.Serialize(&roots);
+  ProgramSerializationRoots roots(objects, object_store);
+  objects = serializer.Serialize(&roots);
+  if (units != nullptr) {
+    (*units)[LoadingUnit::kRootId]->set_objects(objects);
+  }
   serializer.FillHeader(serializer.kind());
   clustered_isolate_size_ = serializer.bytes_written();
 
@@ -7003,7 +7053,8 @@
   serializer.Write(program_hash);
 
   UnitSerializationRoots roots(unit);
-  serializer.Serialize(&roots);
+  unit->set_objects(serializer.Serialize(&roots));
+
   serializer.FillHeader(serializer.kind());
   clustered_isolate_size_ = serializer.bytes_written();
 
@@ -7026,16 +7077,15 @@
 
 void FullSnapshotWriter::WriteFullSnapshot(
     GrowableArray<LoadingUnitSerializationData*>* data) {
-  intptr_t num_base_objects;
+  ZoneGrowableArray<Object*>* objects;
   if (vm_snapshot_data_ != nullptr) {
-    num_base_objects = WriteVMSnapshot();
-    ASSERT(num_base_objects != 0);
+    objects = WriteVMSnapshot();
   } else {
-    num_base_objects = 0;
+    objects = nullptr;
   }
 
   if (isolate_snapshot_data_ != nullptr) {
-    WriteProgramSnapshot(num_base_objects, data);
+    WriteProgramSnapshot(objects, data);
   }
 
   if (FLAG_print_snapshot_sizes) {
diff --git a/runtime/vm/clustered_snapshot.h b/runtime/vm/clustered_snapshot.h
index ab079c8..56ba846 100644
--- a/runtime/vm/clustered_snapshot.h
+++ b/runtime/vm/clustered_snapshot.h
@@ -54,22 +54,28 @@
  public:
   LoadingUnitSerializationData(intptr_t id,
                                LoadingUnitSerializationData* parent)
-      : id_(id), parent_(parent), deferred_objects_(), num_objects_(0) {}
+      : id_(id), parent_(parent), deferred_objects_(), objects_(nullptr) {}
 
   intptr_t id() const { return id_; }
   LoadingUnitSerializationData* parent() const { return parent_; }
-  intptr_t num_objects() const { return num_objects_; }
-  void set_num_objects(intptr_t value) { num_objects_ = value; }
   void AddDeferredObject(CodePtr obj) {
     deferred_objects_.Add(&Code::ZoneHandle(obj));
   }
   GrowableArray<Code*>* deferred_objects() { return &deferred_objects_; }
+  ZoneGrowableArray<Object*>* objects() {
+    ASSERT(objects_ != nullptr);
+    return objects_;
+  }
+  void set_objects(ZoneGrowableArray<Object*>* objects) {
+    ASSERT(objects_ == nullptr);
+    objects_ = objects;
+  }
 
  private:
   intptr_t id_;
   LoadingUnitSerializationData* parent_;
   GrowableArray<Code*> deferred_objects_;
-  intptr_t num_objects_;
+  ZoneGrowableArray<Object*>* objects_;
 };
 
 class SerializationCluster : public ZoneAllocated {
@@ -202,59 +208,9 @@
 
   void AddBaseObject(ObjectPtr base_object,
                      const char* type = nullptr,
-                     const char* name = nullptr) {
-    intptr_t ref = AssignRef(base_object);
-    num_base_objects_++;
-
-    if (profile_writer_ != nullptr) {
-      if (type == nullptr) {
-        type = "Unknown";
-      }
-      if (name == nullptr) {
-        name = "<base object>";
-      }
-      profile_writer_->SetObjectTypeAndName(
-          {V8SnapshotProfileWriter::kSnapshot, ref}, type, name);
-      profile_writer_->AddRoot({V8SnapshotProfileWriter::kSnapshot, ref});
-    }
-  }
-  void CarryOverBaseObjects(intptr_t num_base_objects) {
-    num_base_objects_ = num_base_objects;
-    next_ref_index_ = num_base_objects + 1;
-  }
-
-  intptr_t AssignRef(ObjectPtr object) {
-    ASSERT(IsAllocatedReference(next_ref_index_));
-    if (object->IsHeapObject()) {
-      // The object id weak table holds image offsets for Instructions instead
-      // of ref indices.
-      ASSERT(!object->IsInstructions());
-      heap_->SetObjectId(object, next_ref_index_);
-      ASSERT(heap_->GetObjectId(object) == next_ref_index_);
-    } else {
-      SmiPtr smi = Smi::RawCast(object);
-      SmiObjectIdPair* existing_pair = smi_ids_.Lookup(smi);
-      if (existing_pair != NULL) {
-        ASSERT(existing_pair->id_ == kUnallocatedReference);
-        existing_pair->id_ = next_ref_index_;
-      } else {
-        SmiObjectIdPair new_pair;
-        new_pair.smi_ = smi;
-        new_pair.id_ = next_ref_index_;
-        smi_ids_.Insert(new_pair);
-      }
-    }
-    return next_ref_index_++;
-  }
-
-  intptr_t AssignArtificialRef(ObjectPtr object) {
-    ASSERT(object.IsHeapObject());
-    const intptr_t ref = -(next_ref_index_++);
-    ASSERT(IsArtificialReference(ref));
-    heap_->SetObjectId(object, ref);
-    ASSERT(heap_->GetObjectId(object) == ref);
-    return ref;
-  }
+                     const char* name = nullptr);
+  intptr_t AssignRef(ObjectPtr object);
+  intptr_t AssignArtificialRef(ObjectPtr object);
 
   void Push(ObjectPtr object);
 
@@ -283,7 +239,7 @@
 
   void WriteVersionAndFeatures(bool is_vm_snapshot);
 
-  intptr_t Serialize(SerializationRoots* roots);
+  ZoneGrowableArray<Object*>* Serialize(SerializationRoots* roots);
   void PrintSnapshotSizes();
 
   FieldTable* field_table() { return field_table_; }
@@ -537,6 +493,7 @@
 
   intptr_t current_loading_unit_id_ = 0;
   GrowableArray<LoadingUnitSerializationData*>* loading_units_ = nullptr;
+  ZoneGrowableArray<Object*>* objects_ = new ZoneGrowableArray<Object*>();
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(Serializer);
 };
@@ -765,10 +722,10 @@
 
  private:
   // Writes a snapshot of the VM Isolate.
-  intptr_t WriteVMSnapshot();
+  ZoneGrowableArray<Object*>* WriteVMSnapshot();
 
   // Writes a full snapshot of regular Dart isolate group.
-  void WriteProgramSnapshot(intptr_t num_base_objects,
+  void WriteProgramSnapshot(ZoneGrowableArray<Object*>* objects,
                             GrowableArray<LoadingUnitSerializationData*>* data);
 
   Thread* thread_;
diff --git a/runtime/vm/dart_api_impl.cc b/runtime/vm/dart_api_impl.cc
index d638bcf..df7a2b7 100644
--- a/runtime/vm/dart_api_impl.cc
+++ b/runtime/vm/dart_api_impl.cc
@@ -1415,6 +1415,8 @@
     BackgroundCompiler::Stop(isolate);
     isolate->heap()->WaitForMarkerTasks(thread);
     isolate->heap()->WaitForSweeperTasks(thread);
+    SafepointOperationScope safepoint_operation(thread);
+    isolate->group()->ReleaseStoreBuffers();
     RELEASE_ASSERT(isolate->heap()->old_space()->tasks() == 0);
   }
 
diff --git a/runtime/vm/heap/heap.cc b/runtime/vm/heap/heap.cc
index 2acdfd3..0d2ac0c 100644
--- a/runtime/vm/heap/heap.cc
+++ b/runtime/vm/heap/heap.cc
@@ -723,6 +723,16 @@
     new_weak_tables_[i]->MergeFrom(donor->new_weak_tables_[i]);
     old_weak_tables_[i]->MergeFrom(donor->old_weak_tables_[i]);
   }
+
+  StoreBufferBlock* block =
+      donor->isolate_group()->store_buffer()->TakeBlocks();
+  while (block != nullptr) {
+    StoreBufferBlock* next = block->next();
+    block->set_next(nullptr);
+    isolate_group()->store_buffer()->PushBlock(block,
+                                               StoreBuffer::kIgnoreThreshold);
+    block = next;
+  }
 }
 
 void Heap::CollectForDebugging() {
diff --git a/runtime/vm/heap/pointer_block.h b/runtime/vm/heap/pointer_block.h
index 73cf03b..4a40cd1 100644
--- a/runtime/vm/heap/pointer_block.h
+++ b/runtime/vm/heap/pointer_block.h
@@ -28,6 +28,7 @@
   }
 
   PointerBlock<Size>* next() const { return next_; }
+  void set_next(PointerBlock<Size>* next) { next_ = next; }
 
   intptr_t Count() const { return top_; }
   bool IsFull() const { return Count() == kSize; }
diff --git a/runtime/vm/heap/verifier.cc b/runtime/vm/heap/verifier.cc
index 48610f8..4c2da50 100644
--- a/runtime/vm/heap/verifier.cc
+++ b/runtime/vm/heap/verifier.cc
@@ -53,8 +53,8 @@
             allocated_set_->Contains(OldPage::ToWritable(raw_obj))) {
           continue;
         }
-        uword raw_addr = ObjectLayout::ToAddr(raw_obj);
-        FATAL1("Invalid object pointer encountered %#" Px "\n", raw_addr);
+        FATAL2("Invalid object pointer encountered %#" Px ": %#" Px "\n",
+               reinterpret_cast<uword>(current), static_cast<uword>(raw_obj));
       }
     }
   }
diff --git a/runtime/vm/isolate.cc b/runtime/vm/isolate.cc
index 8f475f6..5aa297b 100644
--- a/runtime/vm/isolate.cc
+++ b/runtime/vm/isolate.cc
@@ -133,6 +133,12 @@
   }
 }
 
+static std::unique_ptr<Message> SerializeMessage(Dart_Port dest_port,
+                                                 Dart_CObject* obj) {
+  ApiMessageWriter writer;
+  return writer.WriteCMessage(obj, dest_port, Message::kNormalPriority);
+}
+
 static InstancePtr DeserializeMessage(Thread* thread, Message* message) {
   if (message == NULL) {
     return Instance::null();
@@ -1447,34 +1453,38 @@
 
   NoReloadScope no_reload_scope(T->isolate(), T);
   // Generate the error and stacktrace strings for the error message.
-  String& exc_str = String::Handle(T->zone());
-  String& stacktrace_str = String::Handle(T->zone());
+  const char* exception_cstr = nullptr;
+  const char* stacktrace_cstr = nullptr;
   if (result.IsUnhandledException()) {
     Zone* zone = T->zone();
     const UnhandledException& uhe = UnhandledException::Cast(result);
     const Instance& exception = Instance::Handle(zone, uhe.exception());
-    Object& tmp = Object::Handle(zone);
-    tmp = DartLibraryCalls::ToString(exception);
-    if (!tmp.IsString()) {
-      tmp = String::New(exception.ToCString());
+    if (exception.raw() == I->object_store()->out_of_memory()) {
+      exception_cstr = "Out of Memory";  // Cf. OutOfMemoryError.toString().
+    } else if (exception.raw() == I->object_store()->stack_overflow()) {
+      exception_cstr = "Stack Overflow";  // Cf. StackOverflowError.toString().
+    } else {
+      const Object& exception_str =
+          Object::Handle(zone, DartLibraryCalls::ToString(exception));
+      if (!exception_str.IsString()) {
+        exception_cstr = exception.ToCString();
+      } else {
+        exception_cstr = exception_str.ToCString();
+      }
     }
-    exc_str ^= tmp.raw();
 
     const Instance& stacktrace = Instance::Handle(zone, uhe.stacktrace());
-    tmp = DartLibraryCalls::ToString(stacktrace);
-    if (!tmp.IsString()) {
-      tmp = String::New(stacktrace.ToCString());
-    }
-    stacktrace_str ^= tmp.raw();
+    stacktrace_cstr = stacktrace.ToCString();
   } else {
-    exc_str = String::New(result.ToErrorCString());
+    exception_cstr = result.ToErrorCString();
   }
   if (result.IsUnwindError()) {
     // When unwinding we don't notify error listeners and we ignore
     // whether errors are fatal for the current isolate.
     return StoreError(T, result);
   } else {
-    bool has_listener = I->NotifyErrorListeners(exc_str, stacktrace_str);
+    bool has_listener =
+        I->NotifyErrorListeners(exception_cstr, stacktrace_cstr);
     if (I->ErrorsFatal()) {
       if (has_listener) {
         T->ClearStickyError();
@@ -2276,21 +2286,32 @@
   }
 }
 
-bool Isolate::NotifyErrorListeners(const String& msg,
-                                   const String& stacktrace) {
+bool Isolate::NotifyErrorListeners(const char* message,
+                                   const char* stacktrace) {
   const GrowableObjectArray& listeners = GrowableObjectArray::Handle(
       current_zone(), isolate_object_store()->error_listeners());
   if (listeners.IsNull()) return false;
 
-  const Array& arr = Array::Handle(current_zone(), Array::New(2));
-  arr.SetAt(0, msg);
-  arr.SetAt(1, stacktrace);
+  Dart_CObject arr;
+  Dart_CObject* arr_values[2];
+  arr.type = Dart_CObject_kArray;
+  arr.value.as_array.length = 2;
+  arr.value.as_array.values = arr_values;
+  Dart_CObject msg;
+  msg.type = Dart_CObject_kString;
+  msg.value.as_string = const_cast<char*>(message);
+  arr_values[0] = &msg;
+  Dart_CObject stack;
+  stack.type = Dart_CObject_kString;
+  stack.value.as_string = const_cast<char*>(stacktrace);
+  arr_values[1] = &stack;
+
   SendPort& listener = SendPort::Handle(current_zone());
   for (intptr_t i = 0; i < listeners.Length(); i++) {
     listener ^= listeners.At(i);
     if (!listener.IsNull()) {
       Dart_Port port_id = listener.Id();
-      PortMap::PostMessage(SerializeMessage(port_id, arr));
+      PortMap::PostMessage(SerializeMessage(port_id, &arr));
     }
   }
   return listeners.Length() > 0;
diff --git a/runtime/vm/isolate.h b/runtime/vm/isolate.h
index 66ff4ec..51d50d91 100644
--- a/runtime/vm/isolate.h
+++ b/runtime/vm/isolate.h
@@ -1004,7 +1004,7 @@
 
   void AddErrorListener(const SendPort& listener);
   void RemoveErrorListener(const SendPort& listener);
-  bool NotifyErrorListeners(const String& msg, const String& stacktrace);
+  bool NotifyErrorListeners(const char* msg, const char* stacktrace);
 
   bool ErrorsFatal() const { return ErrorsFatalBit::decode(isolate_flags_); }
   void SetErrorsFatal(bool val) {
diff --git a/runtime/vm/object_store.cc b/runtime/vm/object_store.cc
index 103f4e8..36705f7 100644
--- a/runtime/vm/object_store.cc
+++ b/runtime/vm/object_store.cc
@@ -55,17 +55,6 @@
 }
 #endif  // !PRODUCT
 
-static UnhandledExceptionPtr CreatePreallocatedUnandledException(
-    Zone* zone,
-    const Object& out_of_memory) {
-  // Allocate pre-allocated unhandled exception object initialized with the
-  // pre-allocated OutOfMemoryError.
-  const UnhandledException& unhandled_exception =
-      UnhandledException::Handle(UnhandledException::New(
-          Instance::Cast(out_of_memory), StackTrace::Handle(zone)));
-  return unhandled_exception.raw();
-}
-
 static StackTracePtr CreatePreallocatedStackTrace(Zone* zone) {
   const Array& code_array = Array::Handle(
       zone, Array::New(StackTrace::kPreallocatedStackdepth, Heap::kOld));
@@ -93,10 +82,12 @@
   // pre-allocated OutOfMemoryError.
   const Object& out_of_memory =
       Object::Handle(zone, object_store_->out_of_memory());
+  const StackTrace& preallocated_stack_trace =
+      StackTrace::Handle(zone, CreatePreallocatedStackTrace(zone));
+  set_preallocated_stack_trace(preallocated_stack_trace);
   set_preallocated_unhandled_exception(UnhandledException::Handle(
-      CreatePreallocatedUnandledException(zone, out_of_memory)));
-  set_preallocated_stack_trace(
-      StackTrace::Handle(CreatePreallocatedStackTrace(zone)));
+      zone, UnhandledException::New(Instance::Cast(out_of_memory),
+                                    preallocated_stack_trace)));
 
   return Error::null();
 }
diff --git a/sdk/lib/_internal/vm/bin/vmservice_server.dart b/sdk/lib/_internal/vm/bin/vmservice_server.dart
index 383b19b..69aa7f8 100644
--- a/sdk/lib/_internal/vm/bin/vmservice_server.dart
+++ b/sdk/lib/_internal/vm/bin/vmservice_server.dart
@@ -369,11 +369,8 @@
           WebSocketClient(webSocket, _service);
         });
       } else {
-        request.response.statusCode = HttpStatus.forbidden;
-        request.response.write('Cannot connect directly to the VM service as '
-            'a Dart Development Service (DDS) instance has taken control and '
-            'can be found at ${_service.ddsUri}.');
-        request.response.close();
+        // Attempt to redirect client to the DDS instance.
+        request.response.redirect(_service.ddsUri!);
       }
       return;
     }
diff --git a/sdk/lib/vmservice/vmservice.dart b/sdk/lib/vmservice/vmservice.dart
index e0ccfaa..755e934 100644
--- a/sdk/lib/vmservice/vmservice.dart
+++ b/sdk/lib/vmservice/vmservice.dart
@@ -239,6 +239,12 @@
           details:
               'Embedder does not support yielding to a VM service intermediary.');
     }
+
+    if (_ddsUri != null) {
+      return encodeRpcError(message, kFeatureDisabled,
+          details: 'A DDS instance is already connected at ${_ddsUri!}.');
+    }
+
     final uri = message.params['uri'];
     if (uri == null) {
       return encodeMissingParamError(message, 'uri');
diff --git a/tests/language_2/getter/setter2_test.dart b/tests/language_2/getter/setter2_test.dart
index a533c41..ad8700b 100644
--- a/tests/language_2/getter/setter2_test.dart
+++ b/tests/language_2/getter/setter2_test.dart
@@ -38,6 +38,7 @@
   A get field {
   //    ^^^^^
   // [analyzer] COMPILE_TIME_ERROR.GETTER_NOT_ASSIGNABLE_SETTER_TYPES
+  // [cfe] The type 'A' of the getter 'T2.field' is not assignable to the type 'C' of the setter 'T2.field'.
     return getterField;
   }
 
diff --git a/tests/standalone/out_of_memory_unhandled_exception_test.dart b/tests/standalone/out_of_memory_unhandled_exception_test.dart
new file mode 100644
index 0000000..7a5935d
--- /dev/null
+++ b/tests/standalone/out_of_memory_unhandled_exception_test.dart
@@ -0,0 +1,36 @@
+// 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 "dart:io";
+
+import "package:expect/expect.dart";
+
+main(args) async {
+  if (args.contains("--child")) {
+    var leak = [];
+    while (true) {
+      leak = [leak];
+    }
+  } else {
+    var exec = Platform.resolvedExecutable;
+    var args = <String>[];
+    args.addAll(Platform.executableArguments);
+    args.add("--old_gen_heap_size=20");
+    args.add(Platform.script.toFilePath());
+    args.add("--child");
+
+    // Should report an unhandled out of memory exception without crashing.
+    print("+ $exec " + args.join(" "));
+    var result = await Process.run(exec, args);
+
+    print("exit: ${result.exitCode}");
+    print("stdout:");
+    print(result.stdout);
+    print("stderr:");
+    print(result.stderr);
+
+    Expect.equals(255, result.exitCode, "Unhandled exception, not crash");
+    Expect.isTrue(result.stderr.contains("Out of Memory"));
+  }
+}
diff --git a/tests/standalone/standalone_kernel.status b/tests/standalone/standalone_kernel.status
index 199fb5a..02cfb78 100644
--- a/tests/standalone/standalone_kernel.status
+++ b/tests/standalone/standalone_kernel.status
@@ -4,9 +4,9 @@
 # Sections in this file should contain "$compiler == dartk" or
 # "$compiler == dartkp".
 
-fragmentation_test: Pass, Slow # GC heavy
 fragmentation_typed_data_test: Pass, Slow # GC heavy
 io/process_sync_test: Pass, Slow # Spawns synchronously subprocesses in sequence.
+out_of_memory_unhandled_exception_test: Pass, Slow
 
 [ $compiler == dartkb ]
 no_lazy_dispatchers_test: SkipByDesign # KBC interpreter doesn't support --no_lazy_dispatchers
diff --git a/tests/standalone_2/out_of_memory_unhandled_exception_test.dart b/tests/standalone_2/out_of_memory_unhandled_exception_test.dart
new file mode 100644
index 0000000..7a5935d
--- /dev/null
+++ b/tests/standalone_2/out_of_memory_unhandled_exception_test.dart
@@ -0,0 +1,36 @@
+// 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 "dart:io";
+
+import "package:expect/expect.dart";
+
+main(args) async {
+  if (args.contains("--child")) {
+    var leak = [];
+    while (true) {
+      leak = [leak];
+    }
+  } else {
+    var exec = Platform.resolvedExecutable;
+    var args = <String>[];
+    args.addAll(Platform.executableArguments);
+    args.add("--old_gen_heap_size=20");
+    args.add(Platform.script.toFilePath());
+    args.add("--child");
+
+    // Should report an unhandled out of memory exception without crashing.
+    print("+ $exec " + args.join(" "));
+    var result = await Process.run(exec, args);
+
+    print("exit: ${result.exitCode}");
+    print("stdout:");
+    print(result.stdout);
+    print("stderr:");
+    print(result.stderr);
+
+    Expect.equals(255, result.exitCode, "Unhandled exception, not crash");
+    Expect.isTrue(result.stderr.contains("Out of Memory"));
+  }
+}
diff --git a/tests/standalone_2/standalone_2_kernel.status b/tests/standalone_2/standalone_2_kernel.status
index 199fb5a..af8e3ec 100644
--- a/tests/standalone_2/standalone_2_kernel.status
+++ b/tests/standalone_2/standalone_2_kernel.status
@@ -7,6 +7,7 @@
 fragmentation_test: Pass, Slow # GC heavy
 fragmentation_typed_data_test: Pass, Slow # GC heavy
 io/process_sync_test: Pass, Slow # Spawns synchronously subprocesses in sequence.
+out_of_memory_unhandled_exception_test: Pass, Slow
 
 [ $compiler == dartkb ]
 no_lazy_dispatchers_test: SkipByDesign # KBC interpreter doesn't support --no_lazy_dispatchers
diff --git a/tools/VERSION b/tools/VERSION
index 81db08d..7693e3e 100644
--- a/tools/VERSION
+++ b/tools/VERSION
@@ -27,5 +27,5 @@
 MAJOR 2
 MINOR 11
 PATCH 0
-PRERELEASE 187
+PRERELEASE 188
 PRERELEASE_PATCH 0
\ No newline at end of file