diff --git a/pkg/_fe_analyzer_shared/test/inference/inferred_type_arguments/data/constructor_invocation.dart b/pkg/_fe_analyzer_shared/test/inference/inferred_type_arguments/data/constructor_invocation.dart
new file mode 100644
index 0000000..4575c37
--- /dev/null
+++ b/pkg/_fe_analyzer_shared/test/inference/inferred_type_arguments/data/constructor_invocation.dart
@@ -0,0 +1,77 @@
+// Copyright (c) 2021, 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.
+
+dynamic dyn = null;
+
+class Unbounded<T> {
+  Unbounded();
+}
+
+class UnboundedArg<T> {
+  UnboundedArg(T t);
+}
+
+class ExtendsNum<T extends num> {
+  ExtendsNum();
+}
+
+class ExtendsNumArg<T extends num> {
+  ExtendsNumArg(T t);
+}
+
+class MultipleArgs<T, U, S> {
+  MultipleArgs(T t, S s, U u);
+}
+
+staticInvocations() {
+  Unbounded/*<dynamic>*/();
+  Unbounded<int>();
+  var unboundedReturn1 = Unbounded/*<dynamic>*/();
+  Unbounded<int> unboundedReturn2 = Unbounded/*<int>*/();
+  Unbounded<num> unboundedReturn3 = Unbounded<int>();
+  Unbounded unboundedReturn4 = Unbounded/*<dynamic>*/();
+
+  UnboundedArg/*<Null>*/(null);
+  UnboundedArg/*<int>*/(0);
+  UnboundedArg/*<String>*/("");
+  UnboundedArg<num>(0);
+  var unboundedReturnArg1 = UnboundedArg/*<int>*/(0);
+  var unboundedReturnArg2 = UnboundedArg/*<String>*/("");
+  UnboundedArg<num> unboundedReturnArg3 = UnboundedArg/*<num>*/(0);
+  UnboundedArg<int> unboundedReturnArg4 = UnboundedArg/*<int>*/(0);
+  UnboundedArg<int> unboundedReturnArg5 = UnboundedArg/*<int>*/(0.5);
+  UnboundedArg<int> unboundedReturnArg6 = UnboundedArg/*<int>*/("");
+  UnboundedArg<int> unboundedReturnArg7 = UnboundedArg<num>(0);
+  UnboundedArg unboundedReturnArg8 = UnboundedArg/*<dynamic>*/(0);
+
+  ExtendsNum/*<num>*/();
+  ExtendsNum<int>();
+  var extendsNumReturn1 = ExtendsNum/*<num>*/();
+  ExtendsNum<int> extendsNumReturn2 = ExtendsNum/*<int>*/();
+  ExtendsNum<num> extendsNumReturn3 = ExtendsNum<int>();
+  ExtendsNum extendsNumReturn4 = ExtendsNum/*<num>*/();
+
+  ExtendsNumArg/*<Null>*/(null);
+  ExtendsNumArg/*<int>*/(0);
+  ExtendsNumArg/*<String>*/("");
+  ExtendsNumArg<num>(0);
+  var extendsNumReturnArg1 = ExtendsNumArg/*<int>*/(0);
+  var extendsNumReturnArg2 = ExtendsNumArg/*<String>*/("");
+  ExtendsNumArg<num> extendsNumReturnArg3 = ExtendsNumArg/*<num>*/(0);
+  ExtendsNumArg<int> extendsNumReturnArg4 = ExtendsNumArg/*<int>*/(0);
+  ExtendsNumArg<int> extendsNumReturnArg5 = ExtendsNumArg/*<int>*/(0.5);
+  ExtendsNumArg<int> extendsNumReturnArg6 = ExtendsNumArg/*<int>*/("");
+  ExtendsNumArg<int> extendsNumReturnArg7 = ExtendsNumArg<num>(0);
+  ExtendsNumArg extendsNumReturnArg8 = ExtendsNumArg/*<num>*/(0);
+
+  MultipleArgs/*<dynamic,dynamic,dynamic>*/(dyn, dyn, dyn);
+  MultipleArgs/*<int,String,bool>*/(0, true, "");
+  MultipleArgs<int, bool, String>(0, true, "");
+  var multipleArgs1 = MultipleArgs();
+  var multipleArgs2 = MultipleArgs/*<int,String,bool>*/(0, true, "");
+  MultipleArgs multipleArgs3 =
+      MultipleArgs/*<dynamic,dynamic,dynamic>*/(0, true, "");
+  MultipleArgs<int, String, bool> multipleArgs4 =
+      MultipleArgs/*<int,String,bool>*/(dyn, dyn, dyn);
+}
diff --git a/pkg/_fe_analyzer_shared/test/inference/inferred_type_arguments/data/function_invocation.dart b/pkg/_fe_analyzer_shared/test/inference/inferred_type_arguments/data/function_invocation.dart
new file mode 100644
index 0000000..f8f8c26
--- /dev/null
+++ b/pkg/_fe_analyzer_shared/test/inference/inferred_type_arguments/data/function_invocation.dart
@@ -0,0 +1,79 @@
+// Copyright (c) 2021, 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.
+
+void Function<T>() unboundedUnused = <T>() {};
+
+void Function<T>(T) unboundedArg = <T>(T t) {};
+
+T Function<T>() unboundedReturn = <T>() => throw '';
+
+T Function<T>(T) unboundedReturnArg = <T>(T t) => t;
+
+void Function<T extends num>() extendsNumUnused = <T extends num>() {};
+
+void Function<T extends num>(T) extendsNumArg = <T extends num>(T t) {};
+
+T Function<T extends num>() extendsNumReturn = <T extends num>() => throw '';
+
+T Function<T extends num>(T) extendsNumReturnArg = <T extends num>(T t) => t;
+
+void Function<T, U, S>(T, S, U) multipleArgs = (T t, S s, U u) {};
+
+functionInvocations() {
+  unboundedUnused/*<dynamic>*/();
+  unboundedUnused<int>();
+
+  unboundedArg/*<Null>*/(null);
+  unboundedArg/*<int>*/(0);
+  unboundedArg/*<String>*/("");
+  unboundedArg<num>(0);
+
+  unboundedReturn/*<dynamic>*/();
+  unboundedReturn<int>();
+  var unboundedReturn1 = unboundedReturn/*<dynamic>*/();
+  int unboundedReturn2 = unboundedReturn/*<int>*/();
+  num unboundedReturn3 = unboundedReturn<int>();
+
+  unboundedReturnArg/*<Null>*/(null);
+  unboundedReturnArg/*<int>*/(0);
+  unboundedReturnArg/*<String>*/("");
+  unboundedReturnArg<num>(0);
+  var unboundedReturnArg1 = unboundedReturnArg/*<int>*/(0);
+  var unboundedReturnArg2 = unboundedReturnArg/*<String>*/("");
+  num unboundedReturnArg3 = unboundedReturnArg/*<num>*/(0);
+  int unboundedReturnArg4 = unboundedReturnArg/*<int>*/(0);
+  int unboundedReturnArg5 = unboundedReturnArg/*<int>*/(0.5);
+  int unboundedReturnArg6 = unboundedReturnArg/*<int>*/("");
+  int unboundedReturnArg7 = unboundedReturnArg<num>(0);
+
+  extendsNumUnused/*<num>*/();
+  extendsNumUnused<int>();
+
+  // TODO(45660): extendsNumArg<Null>(null);
+  extendsNumArg/*<int>*/(0);
+  // TODO(45660): extendsNumArg<String>("");
+  extendsNumArg<num>(0);
+
+  extendsNumReturn/*<num>*/();
+  extendsNumReturn<int>();
+  var extendsNumReturn1 = extendsNumReturn/*<num>*/();
+  int extendsNumReturn2 = extendsNumReturn/*<int>*/();
+  num extendsNumReturn3 = extendsNumReturn<int>();
+
+  // TODO(45660): extendsNumReturnArg(null);
+  extendsNumReturnArg/*<int>*/(0);
+  // TODO(45660): extendsNumReturnArg("");
+  extendsNumReturnArg<num>(0);
+  var extendsNumReturnArg1 = extendsNumReturnArg/*<int>*/(0);
+  // TODO(45660): var extendsNumReturnArg2 = extendsNumReturnArg("");
+  num extendsNumReturnArg3 = extendsNumReturnArg/*<num>*/(0);
+  int extendsNumReturnArg4 = extendsNumReturnArg/*<int>*/(0);
+  int extendsNumReturnArg5 = extendsNumReturnArg/*<int>*/(0.5);
+  int extendsNumReturnArg6 = extendsNumReturnArg/*<int>*/("");
+  int extendsNumReturnArg7 = extendsNumReturnArg<num>(0);
+
+  multipleArgs/*<dynamic,dynamic,dynamic>*/();
+  multipleArgs/*<int,String,bool>*/(0, true, "");
+  multipleArgs<int, bool, String>(0, true, "");
+}
diff --git a/pkg/_fe_analyzer_shared/test/inference/inferred_type_arguments/data/instance_invocation.dart b/pkg/_fe_analyzer_shared/test/inference/inferred_type_arguments/data/instance_invocation.dart
new file mode 100644
index 0000000..0405f0e
--- /dev/null
+++ b/pkg/_fe_analyzer_shared/test/inference/inferred_type_arguments/data/instance_invocation.dart
@@ -0,0 +1,81 @@
+// Copyright (c) 2021, the Dart project authors. Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+class Class {
+  void unboundedUnused<T>() {}
+
+  void unboundedArg<T>(T t) {}
+
+  T unboundedReturn<T>() => throw '';
+
+  T unboundedReturnArg<T>(T t) => t;
+
+  void extendsNumUnused<T extends num>() {}
+
+  void extendsNumArg<T extends num>(T t) {}
+
+  T extendsNumReturn<T extends num>() => throw '';
+
+  T extendsNumReturnArg<T extends num>(T t) => t;
+
+  void multipleArgs<T, U, S>(T t, S s, U u) {}
+
+  instanceInvocations() {
+    unboundedUnused/*<dynamic>*/();
+    unboundedUnused<int>();
+
+    unboundedArg/*<Null>*/(null);
+    unboundedArg/*<int>*/(0);
+    unboundedArg/*<String>*/("");
+    unboundedArg<num>(0);
+
+    unboundedReturn/*<dynamic>*/();
+    unboundedReturn<int>();
+    var unboundedReturn1 = unboundedReturn/*<dynamic>*/();
+    int unboundedReturn2 = unboundedReturn/*<int>*/();
+    num unboundedReturn3 = unboundedReturn<int>();
+
+    unboundedReturnArg/*<Null>*/(null);
+    unboundedReturnArg/*<int>*/(0);
+    unboundedReturnArg/*<String>*/("");
+    unboundedReturnArg<num>(0);
+    var unboundedReturnArg1 = unboundedReturnArg/*<int>*/(0);
+    var unboundedReturnArg2 = unboundedReturnArg/*<String>*/("");
+    num unboundedReturnArg3 = unboundedReturnArg/*<num>*/(0);
+    int unboundedReturnArg4 = unboundedReturnArg/*<int>*/(0);
+    int unboundedReturnArg5 = unboundedReturnArg/*<int>*/(0.5);
+    int unboundedReturnArg6 = unboundedReturnArg/*<int>*/("");
+    int unboundedReturnArg7 = unboundedReturnArg<num>(0);
+
+    extendsNumUnused/*<num>*/();
+    extendsNumUnused<int>();
+
+    extendsNumArg/*<Null>*/(null);
+    extendsNumArg/*<int>*/(0);
+    extendsNumArg/*<String>*/("");
+    extendsNumArg<num>(0);
+
+    extendsNumReturn/*<num>*/();
+    extendsNumReturn<int>();
+    var extendsNumReturn1 = extendsNumReturn/*<num>*/();
+    int extendsNumReturn2 = extendsNumReturn/*<int>*/();
+    num extendsNumReturn3 = extendsNumReturn<int>();
+
+    extendsNumReturnArg/*<Null>*/(null);
+    extendsNumReturnArg/*<int>*/(0);
+    extendsNumReturnArg/*<String>*/("");
+    extendsNumReturnArg<num>(0);
+    var extendsNumReturnArg1 = extendsNumReturnArg/*<int>*/(0);
+    var extendsNumReturnArg2 = extendsNumReturnArg/*<String>*/("");
+    num extendsNumReturnArg3 = extendsNumReturnArg/*<num>*/(0);
+    int extendsNumReturnArg4 = extendsNumReturnArg/*<int>*/(0);
+    int extendsNumReturnArg5 = extendsNumReturnArg/*<int>*/(0.5);
+    int extendsNumReturnArg6 = extendsNumReturnArg/*<int>*/("");
+    int extendsNumReturnArg7 = extendsNumReturnArg<num>(0);
+
+    multipleArgs/*<dynamic,dynamic,dynamic>*/();
+    multipleArgs/*<int,String,bool>*/(0, true, "");
+    multipleArgs<int, bool, String>(0, true, "");
+  }
+}
diff --git a/pkg/_fe_analyzer_shared/test/inference/inferred_type_arguments/data/marker.options b/pkg/_fe_analyzer_shared/test/inference/inferred_type_arguments/data/marker.options
new file mode 100644
index 0000000..b0f2c56
--- /dev/null
+++ b/pkg/_fe_analyzer_shared/test/inference/inferred_type_arguments/data/marker.options
@@ -0,0 +1 @@
+cfe=pkg/front_end/test/id_tests/inferred_type_arguments_test.dart
diff --git a/pkg/_fe_analyzer_shared/test/inference/inferred_type_arguments/data/static_invocation.dart b/pkg/_fe_analyzer_shared/test/inference/inferred_type_arguments/data/static_invocation.dart
new file mode 100644
index 0000000..70932b3
--- /dev/null
+++ b/pkg/_fe_analyzer_shared/test/inference/inferred_type_arguments/data/static_invocation.dart
@@ -0,0 +1,79 @@
+// Copyright (c) 2021, 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.
+
+void unboundedUnused<T>() {}
+
+void unboundedArg<T>(T t) {}
+
+T unboundedReturn<T>() => throw '';
+
+T unboundedReturnArg<T>(T t) => t;
+
+void extendsNumUnused<T extends num>() {}
+
+void extendsNumArg<T extends num>(T t) {}
+
+T extendsNumReturn<T extends num>() => throw '';
+
+T extendsNumReturnArg<T extends num>(T t) => t;
+
+void multipleArgs<T, U, S>(T t, S s, U u) {}
+
+staticInvocations() {
+  unboundedUnused/*<dynamic>*/();
+  unboundedUnused<int>();
+
+  unboundedArg/*<Null>*/(null);
+  unboundedArg/*<int>*/(0);
+  unboundedArg/*<String>*/("");
+  unboundedArg<num>(0);
+
+  unboundedReturn/*<dynamic>*/();
+  unboundedReturn<int>();
+  var unboundedReturn1 = unboundedReturn/*<dynamic>*/();
+  int unboundedReturn2 = unboundedReturn/*<int>*/();
+  num unboundedReturn3 = unboundedReturn<int>();
+
+  unboundedReturnArg/*<Null>*/(null);
+  unboundedReturnArg/*<int>*/(0);
+  unboundedReturnArg/*<String>*/("");
+  unboundedReturnArg<num>(0);
+  var unboundedReturnArg1 = unboundedReturnArg/*<int>*/(0);
+  var unboundedReturnArg2 = unboundedReturnArg/*<String>*/("");
+  num unboundedReturnArg3 = unboundedReturnArg/*<num>*/(0);
+  int unboundedReturnArg4 = unboundedReturnArg/*<int>*/(0);
+  int unboundedReturnArg5 = unboundedReturnArg/*<int>*/(0.5);
+  int unboundedReturnArg6 = unboundedReturnArg/*<int>*/("");
+  int unboundedReturnArg7 = unboundedReturnArg<num>(0);
+
+  extendsNumUnused/*<num>*/();
+  extendsNumUnused<int>();
+
+  extendsNumArg/*<Null>*/(null);
+  extendsNumArg/*<int>*/(0);
+  extendsNumArg/*<String>*/("");
+  extendsNumArg<num>(0);
+
+  extendsNumReturn/*<num>*/();
+  extendsNumReturn<int>();
+  var extendsNumReturn1 = extendsNumReturn/*<num>*/();
+  int extendsNumReturn2 = extendsNumReturn/*<int>*/();
+  num extendsNumReturn3 = extendsNumReturn<int>();
+
+  extendsNumReturnArg/*<Null>*/(null);
+  extendsNumReturnArg/*<int>*/(0);
+  extendsNumReturnArg/*<String>*/("");
+  extendsNumReturnArg<num>(0);
+  var extendsNumReturnArg1 = extendsNumReturnArg/*<int>*/(0);
+  var extendsNumReturnArg2 = extendsNumReturnArg/*<String>*/("");
+  num extendsNumReturnArg3 = extendsNumReturnArg/*<num>*/(0);
+  int extendsNumReturnArg4 = extendsNumReturnArg/*<int>*/(0);
+  int extendsNumReturnArg5 = extendsNumReturnArg/*<int>*/(0.5);
+  int extendsNumReturnArg6 = extendsNumReturnArg/*<int>*/("");
+  int extendsNumReturnArg7 = extendsNumReturnArg<num>(0);
+
+  multipleArgs();
+  multipleArgs/*<int,String,bool>*/(0, true, "");
+  multipleArgs<int, bool, String>(0, true, "");
+}
diff --git a/pkg/front_end/lib/src/fasta/type_inference/type_inference_engine.dart b/pkg/front_end/lib/src/fasta/type_inference/type_inference_engine.dart
index 4a87e32..1fbb4ea 100644
--- a/pkg/front_end/lib/src/fasta/type_inference/type_inference_engine.dart
+++ b/pkg/front_end/lib/src/fasta/type_inference/type_inference_engine.dart
@@ -7,25 +7,7 @@
 import 'package:_fe_analyzer_shared/src/flow_analysis/flow_analysis.dart';
 import 'package:front_end/src/fasta/kernel/internal_ast.dart';
 
-import 'package:kernel/ast.dart'
-    show
-        Constructor,
-        DartType,
-        DartTypeVisitor,
-        Field,
-        FunctionType,
-        FutureOrType,
-        InterfaceType,
-        Member,
-        NamedType,
-        NullType,
-        Statement,
-        TreeNode,
-        TypeParameter,
-        TypeParameterType,
-        TypedefType,
-        VariableDeclaration,
-        Variance;
+import 'package:kernel/ast.dart';
 
 import 'package:kernel/class_hierarchy.dart' show ClassHierarchy;
 
@@ -233,6 +215,9 @@
 
 class InferenceDataForTesting {
   final FlowAnalysisResult flowAnalysisResult = new FlowAnalysisResult();
+
+  final TypeInferenceResultForTesting typeInferenceResult =
+      new TypeInferenceResultForTesting();
 }
 
 /// The result of performing flow analysis on a unit.
@@ -336,3 +321,8 @@
     return from;
   }
 }
+
+/// Type inference results used for testing.
+class TypeInferenceResultForTesting {
+  final Map<Arguments, List<DartType>> inferredTypeArguments = {};
+}
diff --git a/pkg/front_end/lib/src/fasta/type_inference/type_inferrer.dart b/pkg/front_end/lib/src/fasta/type_inference/type_inferrer.dart
index 7acf10f..150f0ba 100644
--- a/pkg/front_end/lib/src/fasta/type_inference/type_inferrer.dart
+++ b/pkg/front_end/lib/src/fasta/type_inference/type_inferrer.dart
@@ -2384,6 +2384,11 @@
           new InstrumentationValueForTypeArgs(inferredTypes));
       arguments.types.clear();
       arguments.types.addAll(inferredTypes);
+      if (dataForTesting != null) {
+        assert(arguments.fileOffset != TreeNode.noOffset);
+        dataForTesting.typeInferenceResult.inferredTypeArguments[arguments] =
+            inferredTypes;
+      }
     }
     List<DartType> positionalArgumentTypes = [];
     List<NamedType> namedArgumentTypes = [];
diff --git a/pkg/front_end/test/id_tests/inferred_type_arguments_test.dart b/pkg/front_end/test/id_tests/inferred_type_arguments_test.dart
new file mode 100644
index 0000000..890e84b
--- /dev/null
+++ b/pkg/front_end/test/id_tests/inferred_type_arguments_test.dart
@@ -0,0 +1,108 @@
+// Copyright (c) 2019, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// @dart = 2.9
+
+import 'dart:io' show Directory, Platform;
+import 'package:_fe_analyzer_shared/src/testing/id.dart' show ActualData, Id;
+import 'package:_fe_analyzer_shared/src/testing/id_testing.dart'
+    show DataInterpreter, runTests;
+import 'package:_fe_analyzer_shared/src/testing/id_testing.dart';
+import 'package:front_end/src/fasta/builder/member_builder.dart';
+import 'package:front_end/src/fasta/type_inference/type_inference_engine.dart';
+import 'package:front_end/src/testing/id_testing_helper.dart';
+import 'package:front_end/src/testing/id_testing_utils.dart';
+import 'package:kernel/ast.dart' hide Variance;
+
+main(List<String> args) async {
+  Directory dataDir = new Directory.fromUri(
+      Platform.script.resolve('../../../_fe_analyzer_shared/test/'
+          'inference/inferred_type_arguments/data'));
+  await runTests<List<DartType>>(dataDir,
+      args: args,
+      createUriForFileName: createUriForFileName,
+      onFailure: onFailure,
+      runTest: runTestFor(const InferredTypeArgumentDataComputer(),
+          [cfeNonNullableOnlyConfig]));
+}
+
+class InferredTypeArgumentDataComputer extends DataComputer<List<DartType>> {
+  const InferredTypeArgumentDataComputer();
+
+  @override
+  DataInterpreter<List<DartType>> get dataValidator =>
+      const _InferredTypeArgumentsDataInterpreter();
+
+  @override
+  bool get supportsErrors => true;
+
+  /// Function that computes a data mapping for [member].
+  ///
+  /// Fills [actualMap] with the data.
+  void computeMemberData(
+      TestConfig config,
+      InternalCompilerResult compilerResult,
+      Member member,
+      Map<Id, ActualData<List<DartType>>> actualMap,
+      {bool verbose}) {
+    MemberBuilderImpl memberBuilder =
+        lookupMemberBuilder(compilerResult, member);
+    member.accept(new InferredTypeArgumentDataExtractor(
+        compilerResult,
+        memberBuilder.dataForTesting.inferenceData.typeInferenceResult,
+        actualMap));
+  }
+}
+
+class InferredTypeArgumentDataExtractor
+    extends CfeDataExtractor<List<DartType>> {
+  final TypeInferenceResultForTesting typeInferenceResult;
+
+  InferredTypeArgumentDataExtractor(InternalCompilerResult compilerResult,
+      this.typeInferenceResult, Map<Id, ActualData<List<DartType>>> actualMap)
+      : super(compilerResult, actualMap);
+
+  @override
+  List<DartType> computeNodeValue(Id id, TreeNode node) {
+    if (node is Arguments) {
+      return typeInferenceResult.inferredTypeArguments[node];
+    }
+    return null;
+  }
+}
+
+class _InferredTypeArgumentsDataInterpreter
+    implements DataInterpreter<List<DartType>> {
+  const _InferredTypeArgumentsDataInterpreter();
+
+  @override
+  String getText(List<DartType> actualData, [String indentation]) {
+    StringBuffer sb = new StringBuffer();
+    if (actualData.isNotEmpty) {
+      sb.write('<');
+      for (int i = 0; i < actualData.length; i++) {
+        if (i > 0) {
+          sb.write(',');
+        }
+        sb.write(typeToText(
+            actualData[i], TypeRepresentation.analyzerNonNullableByDefault));
+      }
+      sb.write('>');
+    }
+    return sb.toString();
+  }
+
+  @override
+  String isAsExpected(List<DartType> actualData, String expectedData) {
+    if (getText(actualData) == expectedData) {
+      return null;
+    } else {
+      return 'Expected $expectedData, got $actualData';
+    }
+  }
+
+  @override
+  bool isEmpty(List<DartType> actualData) =>
+      actualData == null || actualData.isEmpty;
+}
diff --git a/pkg/front_end/testcases/general/issue41210a.dart b/pkg/front_end/testcases/general/issue41210a.dart
index 0b478b1..f736a24 100644
--- a/pkg/front_end/testcases/general/issue41210a.dart
+++ b/pkg/front_end/testcases/general/issue41210a.dart
@@ -1,7 +1,9 @@
 // Copyright (c) 2020, the Dart project authors. Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
+
 // @dart=2.9
+
 abstract class Interface {
   String method(num i);
 }
diff --git a/pkg/front_end/testcases/general/issue41210a.dart.weak.expect b/pkg/front_end/testcases/general/issue41210a.dart.weak.expect
index 2766232..10d9bf9 100644
--- a/pkg/front_end/testcases/general/issue41210a.dart.weak.expect
+++ b/pkg/front_end/testcases/general/issue41210a.dart.weak.expect
@@ -2,13 +2,13 @@
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/general/issue41210a.dart:21:7: Error: Applying the mixin 'B' to 'Object with A' introduces an erroneous override of 'method'.
+// pkg/front_end/testcases/general/issue41210a.dart:23:7: Error: Applying the mixin 'B' to 'Object with A' introduces an erroneous override of 'method'.
 // class C with A, B {} // error
 //       ^
-// pkg/front_end/testcases/general/issue41210a.dart:18:10: Context: The method 'B.method' has fewer named arguments than those of overridden method 'Object with A.method'.
+// pkg/front_end/testcases/general/issue41210a.dart:20:10: Context: The method 'B.method' has fewer named arguments than those of overridden method 'Object with A.method'.
 //   String method(num i);
 //          ^
-// pkg/front_end/testcases/general/issue41210a.dart:21:7: Context: This is the overridden method ('method').
+// pkg/front_end/testcases/general/issue41210a.dart:23:7: Context: This is the overridden method ('method').
 // class C with A, B {} // error
 //       ^
 //
diff --git a/pkg/front_end/testcases/general/issue41210a.dart.weak.outline.expect b/pkg/front_end/testcases/general/issue41210a.dart.weak.outline.expect
index 20bf60b..406be0d 100644
--- a/pkg/front_end/testcases/general/issue41210a.dart.weak.outline.expect
+++ b/pkg/front_end/testcases/general/issue41210a.dart.weak.outline.expect
@@ -2,13 +2,13 @@
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/general/issue41210a.dart:21:7: Error: Applying the mixin 'B' to 'Object with A' introduces an erroneous override of 'method'.
+// pkg/front_end/testcases/general/issue41210a.dart:23:7: Error: Applying the mixin 'B' to 'Object with A' introduces an erroneous override of 'method'.
 // class C with A, B {} // error
 //       ^
-// pkg/front_end/testcases/general/issue41210a.dart:18:10: Context: The method 'B.method' has fewer named arguments than those of overridden method 'Object with A.method'.
+// pkg/front_end/testcases/general/issue41210a.dart:20:10: Context: The method 'B.method' has fewer named arguments than those of overridden method 'Object with A.method'.
 //   String method(num i);
 //          ^
-// pkg/front_end/testcases/general/issue41210a.dart:21:7: Context: This is the overridden method ('method').
+// pkg/front_end/testcases/general/issue41210a.dart:23:7: Context: This is the overridden method ('method').
 // class C with A, B {} // error
 //       ^
 //
diff --git a/pkg/front_end/testcases/general/issue41210a_no_error.dart b/pkg/front_end/testcases/general/issue41210a_no_error.dart
new file mode 100644
index 0000000..e78b1fe
--- /dev/null
+++ b/pkg/front_end/testcases/general/issue41210a_no_error.dart
@@ -0,0 +1,31 @@
+// Copyright (c) 2020, the Dart project authors. Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// @dart=2.9
+
+abstract class Interface {
+  String method(num i);
+}
+
+abstract class Interface2 {
+  String method(covariant int i);
+}
+
+mixin A implements Interface {
+  String method(num i, {String s = "hello"}) => s;
+}
+
+abstract class B implements Interface {
+  String method(num i);
+}
+
+abstract class D implements Interface, Interface2 {}
+
+class E with A, D {} // ok
+
+abstract class F implements Interface {}
+
+class G with A, F {} // ok
+
+main() {}
diff --git a/pkg/front_end/testcases/general/issue41210a_no_error.dart.textual_outline.expect b/pkg/front_end/testcases/general/issue41210a_no_error.dart.textual_outline.expect
new file mode 100644
index 0000000..ed1f176
--- /dev/null
+++ b/pkg/front_end/testcases/general/issue41210a_no_error.dart.textual_outline.expect
@@ -0,0 +1,26 @@
+// @dart = 2.9
+abstract class Interface {
+  String method(num i);
+}
+
+abstract class Interface2 {
+  String method(covariant int i);
+}
+
+mixin A implements Interface {
+  String method(num i, {String s = "hello"}) => s;
+}
+
+abstract class B implements Interface {
+  String method(num i);
+}
+
+abstract class D implements Interface, Interface2 {}
+
+class E with A, D {}
+
+abstract class F implements Interface {}
+
+class G with A, F {}
+
+main() {}
diff --git a/pkg/front_end/testcases/general/issue41210a_no_error.dart.textual_outline_modelled.expect b/pkg/front_end/testcases/general/issue41210a_no_error.dart.textual_outline_modelled.expect
new file mode 100644
index 0000000..224797a
--- /dev/null
+++ b/pkg/front_end/testcases/general/issue41210a_no_error.dart.textual_outline_modelled.expect
@@ -0,0 +1,25 @@
+// @dart = 2.9
+abstract class B implements Interface {
+  String method(num i);
+}
+
+abstract class D implements Interface, Interface2 {}
+
+abstract class F implements Interface {}
+
+abstract class Interface {
+  String method(num i);
+}
+
+abstract class Interface2 {
+  String method(covariant int i);
+}
+
+class E with A, D {}
+
+class G with A, F {}
+
+main() {}
+mixin A implements Interface {
+  String method(num i, {String s = "hello"}) => s;
+}
diff --git a/pkg/front_end/testcases/general/issue41210a_no_error.dart.weak.expect b/pkg/front_end/testcases/general/issue41210a_no_error.dart.weak.expect
new file mode 100644
index 0000000..34d1b47
--- /dev/null
+++ b/pkg/front_end/testcases/general/issue41210a_no_error.dart.weak.expect
@@ -0,0 +1,158 @@
+library;
+import self as self;
+import "dart:core" as core;
+
+abstract class Interface extends core::Object {
+  synthetic constructor •() → self::Interface*
+    : super core::Object::•()
+    ;
+  abstract method method(core::num* i) → 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 Interface2 extends core::Object {
+  synthetic constructor •() → self::Interface2*
+    : super core::Object::•()
+    ;
+  abstract method method(covariant core::int* i) → 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 A extends core::Object implements self::Interface /*isMixinDeclaration*/  {
+  method method(core::num* i, {core::String* s = #C1}) → core::String*
+    return s;
+  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 B extends core::Object implements self::Interface {
+  synthetic constructor •() → self::B*
+    : super core::Object::•()
+    ;
+  abstract method method(core::num* i) → 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 D extends core::Object implements self::Interface, self::Interface2 {
+  synthetic constructor •() → self::D*
+    : super core::Object::•()
+    ;
+  abstract forwarding-stub method method(covariant core::num* i) → 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 _E&Object&A = core::Object with self::A /*isAnonymousMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_E&Object&A*
+    : super core::Object::•()
+    ;
+  mixin-super-stub method method(core::num* i, {core::String* s = #C1}) → core::String*
+    return super.{self::A::method}(i, s: s);
+  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 _E&Object&A&D = self::_E&Object&A with self::D /*isAnonymousMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_E&Object&A&D*
+    : super self::_E&Object&A::•()
+    ;
+  forwarding-stub method method(covariant core::num* i, {core::String* s = #C1}) → core::String*
+    return super.{self::_E&Object&A::method}(i, s: s);
+}
+class E extends self::_E&Object&A&D {
+  synthetic constructor •() → self::E*
+    : super self::_E&Object&A&D::•()
+    ;
+}
+abstract class F extends core::Object implements self::Interface {
+  synthetic constructor •() → self::F*
+    : 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 _G&Object&A = core::Object with self::A /*isAnonymousMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_G&Object&A*
+    : super core::Object::•()
+    ;
+  mixin-super-stub method method(core::num* i, {core::String* s = #C1}) → core::String*
+    return super.{self::A::method}(i, s: s);
+  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 _G&Object&A&F = self::_G&Object&A with self::F /*isAnonymousMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_G&Object&A&F*
+    : super self::_G&Object&A::•()
+    ;
+}
+class G extends self::_G&Object&A&F {
+  synthetic constructor •() → self::G*
+    : super self::_G&Object&A&F::•()
+    ;
+}
+static method main() → dynamic {}
+
+constants  {
+  #C1 = "hello"
+}
diff --git a/pkg/front_end/testcases/general/issue41210a_no_error.dart.weak.outline.expect b/pkg/front_end/testcases/general/issue41210a_no_error.dart.weak.outline.expect
new file mode 100644
index 0000000..babe287
--- /dev/null
+++ b/pkg/front_end/testcases/general/issue41210a_no_error.dart.weak.outline.expect
@@ -0,0 +1,148 @@
+library;
+import self as self;
+import "dart:core" as core;
+
+abstract class Interface extends core::Object {
+  synthetic constructor •() → self::Interface*
+    ;
+  abstract method method(core::num* i) → 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 Interface2 extends core::Object {
+  synthetic constructor •() → self::Interface2*
+    ;
+  abstract method method(covariant core::int* i) → 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 A extends core::Object implements self::Interface /*isMixinDeclaration*/  {
+  method method(core::num* i, {core::String* s = "hello"}) → 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 B extends core::Object implements self::Interface {
+  synthetic constructor •() → self::B*
+    ;
+  abstract method method(core::num* i) → 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 D extends core::Object implements self::Interface, self::Interface2 {
+  synthetic constructor •() → self::D*
+    ;
+  abstract forwarding-stub method method(covariant core::num* i) → 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 _E&Object&A = core::Object with self::A /*isAnonymousMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_E&Object&A*
+    : super core::Object::•()
+    ;
+  mixin-super-stub method method(core::num* i, {core::String* s}) → core::String*
+    return super.{self::A::method}(i, s: s);
+  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 _E&Object&A&D = self::_E&Object&A with self::D /*isAnonymousMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_E&Object&A&D*
+    : super self::_E&Object&A::•()
+    ;
+  forwarding-stub method method(covariant core::num* i, {core::String* s}) → core::String*
+    return super.{self::_E&Object&A::method}(i, s: s);
+}
+class E extends self::_E&Object&A&D {
+  synthetic constructor •() → self::E*
+    ;
+}
+abstract class F extends core::Object implements self::Interface {
+  synthetic constructor •() → self::F*
+    ;
+  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 _G&Object&A = core::Object with self::A /*isAnonymousMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_G&Object&A*
+    : super core::Object::•()
+    ;
+  mixin-super-stub method method(core::num* i, {core::String* s}) → core::String*
+    return super.{self::A::method}(i, s: s);
+  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 _G&Object&A&F = self::_G&Object&A with self::F /*isAnonymousMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_G&Object&A&F*
+    : super self::_G&Object&A::•()
+    ;
+}
+class G extends self::_G&Object&A&F {
+  synthetic constructor •() → self::G*
+    ;
+}
+static method main() → dynamic
+  ;
diff --git a/pkg/front_end/testcases/general/issue41210a_no_error.dart.weak.transformed.expect b/pkg/front_end/testcases/general/issue41210a_no_error.dart.weak.transformed.expect
new file mode 100644
index 0000000..bb1ef4a
--- /dev/null
+++ b/pkg/front_end/testcases/general/issue41210a_no_error.dart.weak.transformed.expect
@@ -0,0 +1,158 @@
+library;
+import self as self;
+import "dart:core" as core;
+
+abstract class Interface extends core::Object {
+  synthetic constructor •() → self::Interface*
+    : super core::Object::•()
+    ;
+  abstract method method(core::num* i) → 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 Interface2 extends core::Object {
+  synthetic constructor •() → self::Interface2*
+    : super core::Object::•()
+    ;
+  abstract method method(covariant core::int* i) → 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 A extends core::Object implements self::Interface /*isMixinDeclaration*/  {
+  method method(core::num* i, {core::String* s = #C1}) → core::String*
+    return s;
+  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 B extends core::Object implements self::Interface {
+  synthetic constructor •() → self::B*
+    : super core::Object::•()
+    ;
+  abstract method method(core::num* i) → 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 D extends core::Object implements self::Interface, self::Interface2 {
+  synthetic constructor •() → self::D*
+    : super core::Object::•()
+    ;
+  abstract forwarding-stub method method(covariant core::num* i) → 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 _E&Object&A extends core::Object implements self::A /*isAnonymousMixin,isEliminatedMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_E&Object&A*
+    : super core::Object::•()
+    ;
+  method method(core::num* i, {core::String* s = #C1}) → core::String*
+    return s;
+  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 _E&Object&A&D extends self::_E&Object&A implements self::D /*isAnonymousMixin,isEliminatedMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_E&Object&A&D*
+    : super self::_E&Object&A::•()
+    ;
+  forwarding-stub method method(covariant core::num* i, {core::String* s = #C1}) → core::String*
+    return super.{self::_E&Object&A::method}(i, s: s);
+}
+class E extends self::_E&Object&A&D {
+  synthetic constructor •() → self::E*
+    : super self::_E&Object&A&D::•()
+    ;
+}
+abstract class F extends core::Object implements self::Interface {
+  synthetic constructor •() → self::F*
+    : 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 _G&Object&A extends core::Object implements self::A /*isAnonymousMixin,isEliminatedMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_G&Object&A*
+    : super core::Object::•()
+    ;
+  method method(core::num* i, {core::String* s = #C1}) → core::String*
+    return s;
+  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 _G&Object&A&F extends self::_G&Object&A implements self::F /*isAnonymousMixin,isEliminatedMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_G&Object&A&F*
+    : super self::_G&Object&A::•()
+    ;
+}
+class G extends self::_G&Object&A&F {
+  synthetic constructor •() → self::G*
+    : super self::_G&Object&A&F::•()
+    ;
+}
+static method main() → dynamic {}
+
+constants  {
+  #C1 = "hello"
+}
diff --git a/pkg/front_end/testcases/general/issue41210b/issue41210.dart b/pkg/front_end/testcases/general/issue41210b/issue41210.dart
index 78d8a27..eb5a4ef 100644
--- a/pkg/front_end/testcases/general/issue41210b/issue41210.dart
+++ b/pkg/front_end/testcases/general/issue41210b/issue41210.dart
@@ -1,7 +1,9 @@
 // Copyright (c) 2020, the Dart project authors. Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
+
 // @dart=2.9
+
 import 'issue41210_lib.dart';
 
 class C with A, B {} // error
diff --git a/pkg/front_end/testcases/general/issue41210b/issue41210.dart.weak.expect b/pkg/front_end/testcases/general/issue41210b/issue41210.dart.weak.expect
index 7273976..38f8cf0 100644
--- a/pkg/front_end/testcases/general/issue41210b/issue41210.dart.weak.expect
+++ b/pkg/front_end/testcases/general/issue41210b/issue41210.dart.weak.expect
@@ -2,13 +2,13 @@
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/general/issue41210b/issue41210.dart:7:7: Error: Applying the mixin 'B' to 'Object with A' introduces an erroneous override of 'method'.
+// pkg/front_end/testcases/general/issue41210b/issue41210.dart:9:7: Error: Applying the mixin 'B' to 'Object with A' introduces an erroneous override of 'method'.
 // class C with A, B {} // error
 //       ^
-// pkg/front_end/testcases/general/issue41210b/issue41210_lib.dart:18:10: Context: The method 'B.method' has fewer named arguments than those of overridden method 'Object with A.method'.
+// pkg/front_end/testcases/general/issue41210b/issue41210_lib.dart:20:10: Context: The method 'B.method' has fewer named arguments than those of overridden method 'Object with A.method'.
 //   String method(num i);
 //          ^
-// pkg/front_end/testcases/general/issue41210b/issue41210.dart:7:7: Context: This is the overridden method ('method').
+// pkg/front_end/testcases/general/issue41210b/issue41210.dart:9:7: Context: This is the overridden method ('method').
 // class C with A, B {} // error
 //       ^
 //
diff --git a/pkg/front_end/testcases/general/issue41210b/issue41210.dart.weak.outline.expect b/pkg/front_end/testcases/general/issue41210b/issue41210.dart.weak.outline.expect
index 3aede9c..5c63262 100644
--- a/pkg/front_end/testcases/general/issue41210b/issue41210.dart.weak.outline.expect
+++ b/pkg/front_end/testcases/general/issue41210b/issue41210.dart.weak.outline.expect
@@ -2,13 +2,13 @@
 //
 // Problems in library:
 //
-// pkg/front_end/testcases/general/issue41210b/issue41210.dart:7:7: Error: Applying the mixin 'B' to 'Object with A' introduces an erroneous override of 'method'.
+// pkg/front_end/testcases/general/issue41210b/issue41210.dart:9:7: Error: Applying the mixin 'B' to 'Object with A' introduces an erroneous override of 'method'.
 // class C with A, B {} // error
 //       ^
-// pkg/front_end/testcases/general/issue41210b/issue41210_lib.dart:18:10: Context: The method 'B.method' has fewer named arguments than those of overridden method 'Object with A.method'.
+// pkg/front_end/testcases/general/issue41210b/issue41210_lib.dart:20:10: Context: The method 'B.method' has fewer named arguments than those of overridden method 'Object with A.method'.
 //   String method(num i);
 //          ^
-// pkg/front_end/testcases/general/issue41210b/issue41210.dart:7:7: Context: This is the overridden method ('method').
+// pkg/front_end/testcases/general/issue41210b/issue41210.dart:9:7: Context: This is the overridden method ('method').
 // class C with A, B {} // error
 //       ^
 //
diff --git a/pkg/front_end/testcases/general/issue41210b/issue41210.no_link.dart.weak.expect b/pkg/front_end/testcases/general/issue41210b/issue41210.no_link.dart.weak.expect
index efd7b7f..f5e9904 100644
--- a/pkg/front_end/testcases/general/issue41210b/issue41210.no_link.dart.weak.expect
+++ b/pkg/front_end/testcases/general/issue41210b/issue41210.no_link.dart.weak.expect
@@ -5,7 +5,7 @@
 // pkg/front_end/testcases/general/issue41210b/issue41210.no_link.dart:7:7: Error: Applying the mixin 'B' to 'Object with A' introduces an erroneous override of 'method'.
 // class C with A, B {} // error
 //       ^
-// pkg/front_end/testcases/general/issue41210b/issue41210_lib.dart:18:10: Context: The method 'B.method' has fewer named arguments than those of overridden method 'Object with A.method'.
+// pkg/front_end/testcases/general/issue41210b/issue41210_lib.dart:20:10: Context: The method 'B.method' has fewer named arguments than those of overridden method 'Object with A.method'.
 //   String method(num i);
 //          ^
 // pkg/front_end/testcases/general/issue41210b/issue41210.no_link.dart:7:7: Context: This is the overridden method ('method').
diff --git a/pkg/front_end/testcases/general/issue41210b/issue41210.no_link.dart.weak.outline.expect b/pkg/front_end/testcases/general/issue41210b/issue41210.no_link.dart.weak.outline.expect
index cb4f387..17ea021 100644
--- a/pkg/front_end/testcases/general/issue41210b/issue41210.no_link.dart.weak.outline.expect
+++ b/pkg/front_end/testcases/general/issue41210b/issue41210.no_link.dart.weak.outline.expect
@@ -5,7 +5,7 @@
 // pkg/front_end/testcases/general/issue41210b/issue41210.no_link.dart:7:7: Error: Applying the mixin 'B' to 'Object with A' introduces an erroneous override of 'method'.
 // class C with A, B {} // error
 //       ^
-// pkg/front_end/testcases/general/issue41210b/issue41210_lib.dart:18:10: Context: The method 'B.method' has fewer named arguments than those of overridden method 'Object with A.method'.
+// pkg/front_end/testcases/general/issue41210b/issue41210_lib.dart:20:10: Context: The method 'B.method' has fewer named arguments than those of overridden method 'Object with A.method'.
 //   String method(num i);
 //          ^
 // pkg/front_end/testcases/general/issue41210b/issue41210.no_link.dart:7:7: Context: This is the overridden method ('method').
diff --git a/pkg/front_end/testcases/general/issue41210b/issue41210_lib.dart b/pkg/front_end/testcases/general/issue41210b/issue41210_lib.dart
index 8601726..04f13b4 100644
--- a/pkg/front_end/testcases/general/issue41210b/issue41210_lib.dart
+++ b/pkg/front_end/testcases/general/issue41210b/issue41210_lib.dart
@@ -1,7 +1,9 @@
 // Copyright (c) 2020, the Dart project authors. Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
+
 // @dart=2.9
+
 abstract class Interface {
   String method(num i);
 }
diff --git a/pkg/front_end/testcases/general/issue41210b/issue41210_no_error.dart b/pkg/front_end/testcases/general/issue41210b/issue41210_no_error.dart
new file mode 100644
index 0000000..ccafb03
--- /dev/null
+++ b/pkg/front_end/testcases/general/issue41210b/issue41210_no_error.dart
@@ -0,0 +1,13 @@
+// Copyright (c) 2020, the Dart project authors. Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// @dart=2.9
+
+import 'issue41210_lib.dart';
+
+class E with A, D {} // ok
+
+class G with A, F {} // ok
+
+main() {}
diff --git a/pkg/front_end/testcases/general/issue41210b/issue41210_no_error.dart.textual_outline.expect b/pkg/front_end/testcases/general/issue41210b/issue41210_no_error.dart.textual_outline.expect
new file mode 100644
index 0000000..7d7c3ca
--- /dev/null
+++ b/pkg/front_end/testcases/general/issue41210b/issue41210_no_error.dart.textual_outline.expect
@@ -0,0 +1,8 @@
+// @dart = 2.9
+import 'issue41210_lib.dart';
+
+class E with A, D {}
+
+class G with A, F {}
+
+main() {}
diff --git a/pkg/front_end/testcases/general/issue41210b/issue41210_no_error.dart.textual_outline_modelled.expect b/pkg/front_end/testcases/general/issue41210b/issue41210_no_error.dart.textual_outline_modelled.expect
new file mode 100644
index 0000000..7d7c3ca
--- /dev/null
+++ b/pkg/front_end/testcases/general/issue41210b/issue41210_no_error.dart.textual_outline_modelled.expect
@@ -0,0 +1,8 @@
+// @dart = 2.9
+import 'issue41210_lib.dart';
+
+class E with A, D {}
+
+class G with A, F {}
+
+main() {}
diff --git a/pkg/front_end/testcases/general/issue41210b/issue41210_no_error.dart.weak.expect b/pkg/front_end/testcases/general/issue41210b/issue41210_no_error.dart.weak.expect
new file mode 100644
index 0000000..26a6ec7
--- /dev/null
+++ b/pkg/front_end/testcases/general/issue41210b/issue41210_no_error.dart.weak.expect
@@ -0,0 +1,166 @@
+library;
+import self as self;
+import "dart:core" as core;
+import "issue41210_lib.dart" as iss;
+
+import "org-dartlang-testcase:///issue41210_lib.dart";
+
+abstract class _E&Object&A = core::Object with iss::A /*isAnonymousMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_E&Object&A*
+    : 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
+  mixin-super-stub method method(core::num* i, {core::String* s = #C1}) → core::String*
+    return super.{iss::A::method}(i, s: s);
+}
+abstract class _E&Object&A&D = self::_E&Object&A with iss::D /*isAnonymousMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_E&Object&A&D*
+    : super self::_E&Object&A::•()
+    ;
+  forwarding-stub method method(covariant core::num* i, {core::String* s = #C1}) → core::String*
+    return super.{self::_E&Object&A::method}(i, s: s);
+}
+class E extends self::_E&Object&A&D {
+  synthetic constructor •() → self::E*
+    : super self::_E&Object&A&D::•()
+    ;
+}
+abstract class _G&Object&A = core::Object with iss::A /*isAnonymousMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_G&Object&A*
+    : 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
+  mixin-super-stub method method(core::num* i, {core::String* s = #C1}) → core::String*
+    return super.{iss::A::method}(i, s: s);
+}
+abstract class _G&Object&A&F = self::_G&Object&A with iss::F /*isAnonymousMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_G&Object&A&F*
+    : super self::_G&Object&A::•()
+    ;
+}
+class G extends self::_G&Object&A&F {
+  synthetic constructor •() → self::G*
+    : super self::_G&Object&A&F::•()
+    ;
+}
+static method main() → dynamic {}
+
+library;
+import self as iss;
+import "dart:core" as core;
+
+abstract class Interface extends core::Object {
+  synthetic constructor •() → iss::Interface*
+    : super core::Object::•()
+    ;
+  abstract method method(core::num* i) → 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 Interface2 extends core::Object {
+  synthetic constructor •() → iss::Interface2*
+    : super core::Object::•()
+    ;
+  abstract method method(covariant core::int* i) → 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 A extends core::Object implements iss::Interface /*isMixinDeclaration*/  {
+  method method(core::num* i, {core::String* s = #C1}) → core::String*
+    return s;
+  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 B extends core::Object implements iss::Interface {
+  synthetic constructor •() → iss::B*
+    : super core::Object::•()
+    ;
+  abstract method method(core::num* i) → 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 D extends core::Object implements iss::Interface, iss::Interface2 {
+  synthetic constructor •() → iss::D*
+    : 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 forwarding-stub method method(covariant core::num* i) → core::String*;
+}
+abstract class F extends core::Object implements iss::Interface {
+  synthetic constructor •() → iss::F*
+    : 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
+}
+
+constants  {
+  #C1 = "hello"
+}
diff --git a/pkg/front_end/testcases/general/issue41210b/issue41210_no_error.dart.weak.outline.expect b/pkg/front_end/testcases/general/issue41210b/issue41210_no_error.dart.weak.outline.expect
new file mode 100644
index 0000000..e89c33b
--- /dev/null
+++ b/pkg/front_end/testcases/general/issue41210b/issue41210_no_error.dart.weak.outline.expect
@@ -0,0 +1,160 @@
+library;
+import self as self;
+import "dart:core" as core;
+import "issue41210_lib.dart" as iss;
+
+import "org-dartlang-testcase:///issue41210_lib.dart";
+
+abstract class _E&Object&A = core::Object with iss::A /*isAnonymousMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_E&Object&A*
+    : 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
+  mixin-super-stub method method(core::num* i, {core::String* s}) → core::String*
+    return super.{iss::A::method}(i, s: s);
+}
+abstract class _E&Object&A&D = self::_E&Object&A with iss::D /*isAnonymousMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_E&Object&A&D*
+    : super self::_E&Object&A::•()
+    ;
+  forwarding-stub method method(covariant core::num* i, {core::String* s}) → core::String*
+    return super.{self::_E&Object&A::method}(i, s: s);
+}
+class E extends self::_E&Object&A&D {
+  synthetic constructor •() → self::E*
+    ;
+}
+abstract class _G&Object&A = core::Object with iss::A /*isAnonymousMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_G&Object&A*
+    : 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
+  mixin-super-stub method method(core::num* i, {core::String* s}) → core::String*
+    return super.{iss::A::method}(i, s: s);
+}
+abstract class _G&Object&A&F = self::_G&Object&A with iss::F /*isAnonymousMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_G&Object&A&F*
+    : super self::_G&Object&A::•()
+    ;
+}
+class G extends self::_G&Object&A&F {
+  synthetic constructor •() → self::G*
+    ;
+}
+static method main() → dynamic
+  ;
+
+library;
+import self as iss;
+import "dart:core" as core;
+
+abstract class Interface extends core::Object {
+  synthetic constructor •() → iss::Interface*
+    ;
+  abstract method method(core::num* i) → 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 Interface2 extends core::Object {
+  synthetic constructor •() → iss::Interface2*
+    ;
+  abstract method method(covariant core::int* i) → 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 A extends core::Object implements iss::Interface /*isMixinDeclaration*/  {
+  method method(core::num* i, {core::String* s = #C1}) → 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 B extends core::Object implements iss::Interface {
+  synthetic constructor •() → iss::B*
+    ;
+  abstract method method(core::num* i) → 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 D extends core::Object implements iss::Interface, iss::Interface2 {
+  synthetic constructor •() → iss::D*
+    ;
+  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 forwarding-stub method method(covariant core::num* i) → core::String*;
+}
+abstract class F extends core::Object implements iss::Interface {
+  synthetic constructor •() → iss::F*
+    ;
+  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
+}
+
+constants  {
+  #C1 = "hello"
+}
diff --git a/pkg/front_end/testcases/general/issue41210b/issue41210_no_error.dart.weak.transformed.expect b/pkg/front_end/testcases/general/issue41210b/issue41210_no_error.dart.weak.transformed.expect
new file mode 100644
index 0000000..b06070d
--- /dev/null
+++ b/pkg/front_end/testcases/general/issue41210b/issue41210_no_error.dart.weak.transformed.expect
@@ -0,0 +1,166 @@
+library;
+import self as self;
+import "dart:core" as core;
+import "issue41210_lib.dart" as iss;
+
+import "org-dartlang-testcase:///issue41210_lib.dart";
+
+abstract class _E&Object&A extends core::Object implements iss::A /*isAnonymousMixin,isEliminatedMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_E&Object&A*
+    : 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
+  method /* from org-dartlang-testcase:///issue41210_lib.dart */ method(core::num* i, {core::String* s = #C1}) → core::String*
+    return s;
+}
+abstract class _E&Object&A&D extends self::_E&Object&A implements iss::D /*isAnonymousMixin,isEliminatedMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_E&Object&A&D*
+    : super self::_E&Object&A::•()
+    ;
+  forwarding-stub method method(covariant core::num* i, {core::String* s = #C1}) → core::String*
+    return super.{self::_E&Object&A::method}(i, s: s);
+}
+class E extends self::_E&Object&A&D {
+  synthetic constructor •() → self::E*
+    : super self::_E&Object&A&D::•()
+    ;
+}
+abstract class _G&Object&A extends core::Object implements iss::A /*isAnonymousMixin,isEliminatedMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_G&Object&A*
+    : 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
+  method /* from org-dartlang-testcase:///issue41210_lib.dart */ method(core::num* i, {core::String* s = #C1}) → core::String*
+    return s;
+}
+abstract class _G&Object&A&F extends self::_G&Object&A implements iss::F /*isAnonymousMixin,isEliminatedMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_G&Object&A&F*
+    : super self::_G&Object&A::•()
+    ;
+}
+class G extends self::_G&Object&A&F {
+  synthetic constructor •() → self::G*
+    : super self::_G&Object&A&F::•()
+    ;
+}
+static method main() → dynamic {}
+
+library;
+import self as iss;
+import "dart:core" as core;
+
+abstract class Interface extends core::Object {
+  synthetic constructor •() → iss::Interface*
+    : super core::Object::•()
+    ;
+  abstract method method(core::num* i) → 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 Interface2 extends core::Object {
+  synthetic constructor •() → iss::Interface2*
+    : super core::Object::•()
+    ;
+  abstract method method(covariant core::int* i) → 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 A extends core::Object implements iss::Interface /*isMixinDeclaration*/  {
+  method method(core::num* i, {core::String* s = #C1}) → core::String*
+    return s;
+  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 B extends core::Object implements iss::Interface {
+  synthetic constructor •() → iss::B*
+    : super core::Object::•()
+    ;
+  abstract method method(core::num* i) → 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 D extends core::Object implements iss::Interface, iss::Interface2 {
+  synthetic constructor •() → iss::D*
+    : 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 forwarding-stub method method(covariant core::num* i) → core::String*;
+}
+abstract class F extends core::Object implements iss::Interface {
+  synthetic constructor •() → iss::F*
+    : 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
+}
+
+constants  {
+  #C1 = "hello"
+}
diff --git a/pkg/front_end/testcases/general/issue41210b/issue41210_no_error.no_link.dart b/pkg/front_end/testcases/general/issue41210b/issue41210_no_error.no_link.dart
new file mode 100644
index 0000000..ccafb03
--- /dev/null
+++ b/pkg/front_end/testcases/general/issue41210b/issue41210_no_error.no_link.dart
@@ -0,0 +1,13 @@
+// Copyright (c) 2020, the Dart project authors. Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// @dart=2.9
+
+import 'issue41210_lib.dart';
+
+class E with A, D {} // ok
+
+class G with A, F {} // ok
+
+main() {}
diff --git a/pkg/front_end/testcases/general/issue41210b/issue41210_no_error.no_link.dart.textual_outline.expect b/pkg/front_end/testcases/general/issue41210b/issue41210_no_error.no_link.dart.textual_outline.expect
new file mode 100644
index 0000000..7d7c3ca
--- /dev/null
+++ b/pkg/front_end/testcases/general/issue41210b/issue41210_no_error.no_link.dart.textual_outline.expect
@@ -0,0 +1,8 @@
+// @dart = 2.9
+import 'issue41210_lib.dart';
+
+class E with A, D {}
+
+class G with A, F {}
+
+main() {}
diff --git a/pkg/front_end/testcases/general/issue41210b/issue41210_no_error.no_link.dart.textual_outline_modelled.expect b/pkg/front_end/testcases/general/issue41210b/issue41210_no_error.no_link.dart.textual_outline_modelled.expect
new file mode 100644
index 0000000..7d7c3ca
--- /dev/null
+++ b/pkg/front_end/testcases/general/issue41210b/issue41210_no_error.no_link.dart.textual_outline_modelled.expect
@@ -0,0 +1,8 @@
+// @dart = 2.9
+import 'issue41210_lib.dart';
+
+class E with A, D {}
+
+class G with A, F {}
+
+main() {}
diff --git a/pkg/front_end/testcases/general/issue41210b/issue41210_no_error.no_link.dart.weak.expect b/pkg/front_end/testcases/general/issue41210b/issue41210_no_error.no_link.dart.weak.expect
new file mode 100644
index 0000000..004a42d
--- /dev/null
+++ b/pkg/front_end/testcases/general/issue41210b/issue41210_no_error.no_link.dart.weak.expect
@@ -0,0 +1,166 @@
+library;
+import self as self;
+import "dart:core" as core;
+import "issue41210_lib.dart" as iss;
+
+import "org-dartlang-testcase:///issue41210_lib.dart";
+
+abstract class _E&Object&A = core::Object with iss::A /*isAnonymousMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_E&Object&A*
+    : super core::Object::•()
+    ;
+  mixin-super-stub method method(core::num* i, {core::String* s = #C1}) → core::String*
+    return super.{iss::A::method}(i, s: s);
+  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 _E&Object&A&D = self::_E&Object&A with iss::D /*isAnonymousMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_E&Object&A&D*
+    : super self::_E&Object&A::•()
+    ;
+  forwarding-stub method method(covariant core::num* i, {core::String* s = #C1}) → core::String*
+    return super.{self::_E&Object&A::method}(i, s: s);
+}
+class E extends self::_E&Object&A&D {
+  synthetic constructor •() → self::E*
+    : super self::_E&Object&A&D::•()
+    ;
+}
+abstract class _G&Object&A = core::Object with iss::A /*isAnonymousMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_G&Object&A*
+    : super core::Object::•()
+    ;
+  mixin-super-stub method method(core::num* i, {core::String* s = #C1}) → core::String*
+    return super.{iss::A::method}(i, s: s);
+  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 _G&Object&A&F = self::_G&Object&A with iss::F /*isAnonymousMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_G&Object&A&F*
+    : super self::_G&Object&A::•()
+    ;
+}
+class G extends self::_G&Object&A&F {
+  synthetic constructor •() → self::G*
+    : super self::_G&Object&A&F::•()
+    ;
+}
+static method main() → dynamic {}
+
+library;
+import self as iss;
+import "dart:core" as core;
+
+abstract class Interface extends core::Object {
+  synthetic constructor •() → iss::Interface*
+    : super core::Object::•()
+    ;
+  abstract method method(core::num* i) → 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 Interface2 extends core::Object {
+  synthetic constructor •() → iss::Interface2*
+    : super core::Object::•()
+    ;
+  abstract method method(covariant core::int* i) → 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 A extends core::Object implements iss::Interface /*isMixinDeclaration*/  {
+  method method(core::num* i, {core::String* s = #C1}) → core::String*
+    return s;
+  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 B extends core::Object implements iss::Interface {
+  synthetic constructor •() → iss::B*
+    : super core::Object::•()
+    ;
+  abstract method method(core::num* i) → 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 D extends core::Object implements iss::Interface, iss::Interface2 {
+  synthetic constructor •() → iss::D*
+    : super core::Object::•()
+    ;
+  abstract forwarding-stub method method(covariant core::num* i) → 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 F extends core::Object implements iss::Interface {
+  synthetic constructor •() → iss::F*
+    : 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
+}
+
+constants  {
+  #C1 = "hello"
+}
diff --git a/pkg/front_end/testcases/general/issue41210b/issue41210_no_error.no_link.dart.weak.outline.expect b/pkg/front_end/testcases/general/issue41210b/issue41210_no_error.no_link.dart.weak.outline.expect
new file mode 100644
index 0000000..f82c8a7
--- /dev/null
+++ b/pkg/front_end/testcases/general/issue41210b/issue41210_no_error.no_link.dart.weak.outline.expect
@@ -0,0 +1,156 @@
+library;
+import self as self;
+import "dart:core" as core;
+import "issue41210_lib.dart" as iss;
+
+import "org-dartlang-testcase:///issue41210_lib.dart";
+
+abstract class _E&Object&A = core::Object with iss::A /*isAnonymousMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_E&Object&A*
+    : super core::Object::•()
+    ;
+  mixin-super-stub method method(core::num* i, {core::String* s}) → core::String*
+    return super.{iss::A::method}(i, s: s);
+  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 _E&Object&A&D = self::_E&Object&A with iss::D /*isAnonymousMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_E&Object&A&D*
+    : super self::_E&Object&A::•()
+    ;
+  forwarding-stub method method(covariant core::num* i, {core::String* s}) → core::String*
+    return super.{self::_E&Object&A::method}(i, s: s);
+}
+class E extends self::_E&Object&A&D {
+  synthetic constructor •() → self::E*
+    ;
+}
+abstract class _G&Object&A = core::Object with iss::A /*isAnonymousMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_G&Object&A*
+    : super core::Object::•()
+    ;
+  mixin-super-stub method method(core::num* i, {core::String* s}) → core::String*
+    return super.{iss::A::method}(i, s: s);
+  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 _G&Object&A&F = self::_G&Object&A with iss::F /*isAnonymousMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_G&Object&A&F*
+    : super self::_G&Object&A::•()
+    ;
+}
+class G extends self::_G&Object&A&F {
+  synthetic constructor •() → self::G*
+    ;
+}
+static method main() → dynamic
+  ;
+
+library;
+import self as iss;
+import "dart:core" as core;
+
+abstract class Interface extends core::Object {
+  synthetic constructor •() → iss::Interface*
+    ;
+  abstract method method(core::num* i) → 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 Interface2 extends core::Object {
+  synthetic constructor •() → iss::Interface2*
+    ;
+  abstract method method(covariant core::int* i) → 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 A extends core::Object implements iss::Interface /*isMixinDeclaration*/  {
+  method method(core::num* i, {core::String* s = "hello"}) → 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 B extends core::Object implements iss::Interface {
+  synthetic constructor •() → iss::B*
+    ;
+  abstract method method(core::num* i) → 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 D extends core::Object implements iss::Interface, iss::Interface2 {
+  synthetic constructor •() → iss::D*
+    ;
+  abstract forwarding-stub method method(covariant core::num* i) → 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 F extends core::Object implements iss::Interface {
+  synthetic constructor •() → iss::F*
+    ;
+  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
+}
diff --git a/pkg/front_end/testcases/general/issue41210b/issue41210_no_error.no_link.dart.weak.transformed.expect b/pkg/front_end/testcases/general/issue41210b/issue41210_no_error.no_link.dart.weak.transformed.expect
new file mode 100644
index 0000000..f7cf6a9
--- /dev/null
+++ b/pkg/front_end/testcases/general/issue41210b/issue41210_no_error.no_link.dart.weak.transformed.expect
@@ -0,0 +1,166 @@
+library;
+import self as self;
+import "dart:core" as core;
+import "issue41210_lib.dart" as iss;
+
+import "org-dartlang-testcase:///issue41210_lib.dart";
+
+abstract class _E&Object&A extends core::Object implements iss::A /*isAnonymousMixin,isEliminatedMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_E&Object&A*
+    : super core::Object::•()
+    ;
+  method /* from org-dartlang-testcase:///issue41210_lib.dart */ method(core::num* i, {core::String* s = #C1}) → core::String*
+    return s;
+  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 _E&Object&A&D extends self::_E&Object&A implements iss::D /*isAnonymousMixin,isEliminatedMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_E&Object&A&D*
+    : super self::_E&Object&A::•()
+    ;
+  forwarding-stub method method(covariant core::num* i, {core::String* s = #C1}) → core::String*
+    return super.{self::_E&Object&A::method}(i, s: s);
+}
+class E extends self::_E&Object&A&D {
+  synthetic constructor •() → self::E*
+    : super self::_E&Object&A&D::•()
+    ;
+}
+abstract class _G&Object&A extends core::Object implements iss::A /*isAnonymousMixin,isEliminatedMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_G&Object&A*
+    : super core::Object::•()
+    ;
+  method /* from org-dartlang-testcase:///issue41210_lib.dart */ method(core::num* i, {core::String* s = #C1}) → core::String*
+    return s;
+  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 _G&Object&A&F extends self::_G&Object&A implements iss::F /*isAnonymousMixin,isEliminatedMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_G&Object&A&F*
+    : super self::_G&Object&A::•()
+    ;
+}
+class G extends self::_G&Object&A&F {
+  synthetic constructor •() → self::G*
+    : super self::_G&Object&A&F::•()
+    ;
+}
+static method main() → dynamic {}
+
+library;
+import self as iss;
+import "dart:core" as core;
+
+abstract class Interface extends core::Object {
+  synthetic constructor •() → iss::Interface*
+    : super core::Object::•()
+    ;
+  abstract method method(core::num* i) → 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 Interface2 extends core::Object {
+  synthetic constructor •() → iss::Interface2*
+    : super core::Object::•()
+    ;
+  abstract method method(covariant core::int* i) → 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 A extends core::Object implements iss::Interface /*isMixinDeclaration*/  {
+  method method(core::num* i, {core::String* s = #C1}) → core::String*
+    return s;
+  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 B extends core::Object implements iss::Interface {
+  synthetic constructor •() → iss::B*
+    : super core::Object::•()
+    ;
+  abstract method method(core::num* i) → 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 D extends core::Object implements iss::Interface, iss::Interface2 {
+  synthetic constructor •() → iss::D*
+    : super core::Object::•()
+    ;
+  abstract forwarding-stub method method(covariant core::num* i) → 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 F extends core::Object implements iss::Interface {
+  synthetic constructor •() → iss::F*
+    : 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
+}
+
+constants  {
+  #C1 = "hello"
+}
diff --git a/pkg/front_end/testcases/general/with_dependencies/mixin_from_dill/mixin_from_dill.dart b/pkg/front_end/testcases/general/with_dependencies/mixin_from_dill/mixin_from_dill.dart
index 1d71704..2029f44 100644
--- a/pkg/front_end/testcases/general/with_dependencies/mixin_from_dill/mixin_from_dill.dart
+++ b/pkg/front_end/testcases/general/with_dependencies/mixin_from_dill/mixin_from_dill.dart
@@ -1,7 +1,9 @@
 // Copyright (c) 2020, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
+
 // @dart=2.9
+
 import "mixin_from_dill_lib1.dart" as lib1;
 import "mixin_from_dill_lib2.dart" as lib2;
 
diff --git a/pkg/front_end/testcases/general/with_dependencies/mixin_from_dill/mixin_from_dill.no_link.dart b/pkg/front_end/testcases/general/with_dependencies/mixin_from_dill/mixin_from_dill.no_link.dart
new file mode 100644
index 0000000..2029f44
--- /dev/null
+++ b/pkg/front_end/testcases/general/with_dependencies/mixin_from_dill/mixin_from_dill.no_link.dart
@@ -0,0 +1,19 @@
+// Copyright (c) 2020, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// @dart=2.9
+
+import "mixin_from_dill_lib1.dart" as lib1;
+import "mixin_from_dill_lib2.dart" as lib2;
+
+main() {
+  lib1.Foo foo1 = new lib1.Foo();
+  if (foo1 == null) throw "what?";
+  if (!(foo1 == foo1)) throw "what?";
+  foo1.x();
+  lib2.Foo foo2 = new lib2.Foo();
+  if (foo2 == null) throw "what?";
+  if (!(foo2 == foo2)) throw "what?";
+  foo2.x();
+}
diff --git a/pkg/front_end/testcases/general/with_dependencies/mixin_from_dill/mixin_from_dill.no_link.dart.textual_outline.expect b/pkg/front_end/testcases/general/with_dependencies/mixin_from_dill/mixin_from_dill.no_link.dart.textual_outline.expect
new file mode 100644
index 0000000..3bbec562
--- /dev/null
+++ b/pkg/front_end/testcases/general/with_dependencies/mixin_from_dill/mixin_from_dill.no_link.dart.textual_outline.expect
@@ -0,0 +1,5 @@
+// @dart = 2.9
+import "mixin_from_dill_lib1.dart" as lib1;
+import "mixin_from_dill_lib2.dart" as lib2;
+
+main() {}
diff --git a/pkg/front_end/testcases/general/with_dependencies/mixin_from_dill/mixin_from_dill.no_link.dart.textual_outline_modelled.expect b/pkg/front_end/testcases/general/with_dependencies/mixin_from_dill/mixin_from_dill.no_link.dart.textual_outline_modelled.expect
new file mode 100644
index 0000000..3bbec562
--- /dev/null
+++ b/pkg/front_end/testcases/general/with_dependencies/mixin_from_dill/mixin_from_dill.no_link.dart.textual_outline_modelled.expect
@@ -0,0 +1,5 @@
+// @dart = 2.9
+import "mixin_from_dill_lib1.dart" as lib1;
+import "mixin_from_dill_lib2.dart" as lib2;
+
+main() {}
diff --git a/pkg/front_end/testcases/general/with_dependencies/mixin_from_dill/mixin_from_dill.no_link.dart.weak.expect b/pkg/front_end/testcases/general/with_dependencies/mixin_from_dill/mixin_from_dill.no_link.dart.weak.expect
new file mode 100644
index 0000000..23b3c5d
--- /dev/null
+++ b/pkg/front_end/testcases/general/with_dependencies/mixin_from_dill/mixin_from_dill.no_link.dart.weak.expect
@@ -0,0 +1,174 @@
+library;
+import self as self;
+import "mixin_from_dill_lib1.dart" as mix;
+import "mixin_from_dill_lib2.dart" as mix2;
+
+import "org-dartlang-testcase:///mixin_from_dill_lib1.dart" as lib1;
+import "org-dartlang-testcase:///mixin_from_dill_lib2.dart" as lib2;
+
+static method main() → dynamic {
+  mix::Foo* foo1 = new mix::Foo::•();
+  if(foo1.{mix::_Foo&B&D::==}(null))
+    throw "what?";
+  if(!foo1.{mix::_Foo&B&D::==}(foo1))
+    throw "what?";
+  foo1.{mix::_Foo&B&D::x}();
+  mix2::Foo* foo2 = new mix2::Foo::•();
+  if(foo2.{mix2::_Foo&B&D::==}(null))
+    throw "what?";
+  if(!foo2.{mix2::_Foo&B&D::==}(foo2))
+    throw "what?";
+  foo2.{mix2::_Foo&B&D::x}();
+}
+
+library;
+import self as mix;
+import "dart:core" as core;
+
+abstract class _Foo&B&D = mix::B with mix::D /*isAnonymousMixin*/  {
+  synthetic constructor •() → mix::_Foo&B&D*
+    : super mix::B::•()
+    ;
+  mixin-super-stub operator ==(dynamic dynamic) → core::bool*
+    return super.{mix::D::==}(dynamic);
+  mixin-super-stub method x() → void
+    return super.{mix::D::x}();
+}
+class Foo extends mix::_Foo&B&D {
+  synthetic constructor •() → mix::Foo*
+    : super mix::_Foo&B&D::•()
+    ;
+}
+abstract class B extends core::Object implements mix::C {
+  synthetic constructor •() → mix::B*
+    : super core::Object::•()
+    ;
+  operator ==(dynamic dynamic) → core::bool* {
+    core::print("B.==");
+    return true;
+  }
+  method x() → void {
+    core::print("B.x");
+  }
+  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 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 C extends core::Object {
+  synthetic constructor •() → mix::C*
+    : super core::Object::•()
+    ;
+  abstract member-signature operator ==(dynamic other) → core::bool*; -> 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 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 D extends core::Object implements mix::C {
+  synthetic constructor •() → mix::D*
+    : super core::Object::•()
+    ;
+  operator ==(dynamic dynamic) → core::bool* {
+    core::print("D.==");
+    return true;
+  }
+  method x() → void {
+    core::print("D.x");
+  }
+  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 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
+}
+
+library;
+import self as mix2;
+import "dart:core" as core;
+
+abstract class _Foo&B&D = mix2::B with mix2::D /*isAnonymousMixin*/  {
+  synthetic constructor •() → mix2::_Foo&B&D*
+    : super mix2::B::•()
+    ;
+  mixin-super-stub operator ==(dynamic dynamic) → core::bool*
+    return super.{mix2::D::==}(dynamic);
+  mixin-super-stub method x() → void
+    return super.{mix2::D::x}();
+}
+class Foo extends mix2::_Foo&B&D {
+  synthetic constructor •() → mix2::Foo*
+    : super mix2::_Foo&B&D::•()
+    ;
+}
+abstract class B extends core::Object implements mix2::C {
+  synthetic constructor •() → mix2::B*
+    : super core::Object::•()
+    ;
+  operator ==(dynamic dynamic) → core::bool* {
+    core::print("B.==");
+    return true;
+  }
+  method x() → void {
+    core::print("B.x");
+  }
+  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 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 C extends core::Object {
+  synthetic constructor •() → mix2::C*
+    : super core::Object::•()
+    ;
+  abstract member-signature operator ==(dynamic other) → core::bool*; -> 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 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 D extends core::Object implements mix2::C {
+  synthetic constructor •() → mix2::D*
+    : super core::Object::•()
+    ;
+  operator ==(dynamic dynamic) → core::bool* {
+    core::print("D.==");
+    return true;
+  }
+  method x() → void {
+    core::print("D.x");
+  }
+  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 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
+}
diff --git a/pkg/front_end/testcases/general/with_dependencies/mixin_from_dill/mixin_from_dill.no_link.dart.weak.outline.expect b/pkg/front_end/testcases/general/with_dependencies/mixin_from_dill/mixin_from_dill.no_link.dart.weak.outline.expect
new file mode 100644
index 0000000..4c58fa2
--- /dev/null
+++ b/pkg/front_end/testcases/general/with_dependencies/mixin_from_dill/mixin_from_dill.no_link.dart.weak.outline.expect
@@ -0,0 +1,140 @@
+library;
+import self as self;
+
+import "org-dartlang-testcase:///mixin_from_dill_lib1.dart" as lib1;
+import "org-dartlang-testcase:///mixin_from_dill_lib2.dart" as lib2;
+
+static method main() → dynamic
+  ;
+
+library;
+import self as self2;
+import "dart:core" as core;
+
+abstract class _Foo&B&D = self2::B with self2::D /*isAnonymousMixin*/  {
+  synthetic constructor •() → self2::_Foo&B&D*
+    : super self2::B::•()
+    ;
+  mixin-super-stub operator ==(dynamic dynamic) → core::bool*
+    return super.{self2::D::==}(dynamic);
+  mixin-super-stub method x() → void
+    return super.{self2::D::x}();
+}
+class Foo extends self2::_Foo&B&D {
+  synthetic constructor •() → self2::Foo*
+    ;
+}
+abstract class B extends core::Object implements self2::C {
+  synthetic constructor •() → self2::B*
+    ;
+  operator ==(dynamic dynamic) → core::bool*
+    ;
+  method x() → 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 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 C extends core::Object {
+  synthetic constructor •() → self2::C*
+    ;
+  abstract member-signature operator ==(dynamic other) → core::bool*; -> 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 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 D extends core::Object implements self2::C {
+  synthetic constructor •() → self2::D*
+    ;
+  operator ==(dynamic dynamic) → core::bool*
+    ;
+  method x() → 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 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
+}
+
+library;
+import self as self3;
+import "dart:core" as core;
+
+abstract class _Foo&B&D = self3::B with self3::D /*isAnonymousMixin*/  {
+  synthetic constructor •() → self3::_Foo&B&D*
+    : super self3::B::•()
+    ;
+  mixin-super-stub operator ==(dynamic dynamic) → core::bool*
+    return super.{self3::D::==}(dynamic);
+  mixin-super-stub method x() → void
+    return super.{self3::D::x}();
+}
+class Foo extends self3::_Foo&B&D {
+  synthetic constructor •() → self3::Foo*
+    ;
+}
+abstract class B extends core::Object implements self3::C {
+  synthetic constructor •() → self3::B*
+    ;
+  operator ==(dynamic dynamic) → core::bool*
+    ;
+  method x() → 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 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 C extends core::Object {
+  synthetic constructor •() → self3::C*
+    ;
+  abstract member-signature operator ==(dynamic other) → core::bool*; -> 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 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 D extends core::Object implements self3::C {
+  synthetic constructor •() → self3::D*
+    ;
+  operator ==(dynamic dynamic) → core::bool*
+    ;
+  method x() → 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 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
+}
diff --git a/pkg/front_end/testcases/general/with_dependencies/mixin_from_dill/mixin_from_dill.no_link.dart.weak.transformed.expect b/pkg/front_end/testcases/general/with_dependencies/mixin_from_dill/mixin_from_dill.no_link.dart.weak.transformed.expect
new file mode 100644
index 0000000..06efdba
--- /dev/null
+++ b/pkg/front_end/testcases/general/with_dependencies/mixin_from_dill/mixin_from_dill.no_link.dart.weak.transformed.expect
@@ -0,0 +1,180 @@
+library;
+import self as self;
+import "mixin_from_dill_lib1.dart" as mix;
+import "mixin_from_dill_lib2.dart" as mix2;
+
+import "org-dartlang-testcase:///mixin_from_dill_lib1.dart" as lib1;
+import "org-dartlang-testcase:///mixin_from_dill_lib2.dart" as lib2;
+
+static method main() → dynamic {
+  mix::Foo* foo1 = new mix::Foo::•();
+  if(foo1.{mix::_Foo&B&D::==}(null))
+    throw "what?";
+  if(!foo1.{mix::_Foo&B&D::==}(foo1))
+    throw "what?";
+  foo1.{mix::_Foo&B&D::x}();
+  mix2::Foo* foo2 = new mix2::Foo::•();
+  if(foo2.{mix2::_Foo&B&D::==}(null))
+    throw "what?";
+  if(!foo2.{mix2::_Foo&B&D::==}(foo2))
+    throw "what?";
+  foo2.{mix2::_Foo&B&D::x}();
+}
+
+library;
+import self as mix;
+import "dart:core" as core;
+
+abstract class _Foo&B&D extends mix::B implements mix::D /*isAnonymousMixin,isEliminatedMixin*/  {
+  synthetic constructor •() → mix::_Foo&B&D*
+    : super mix::B::•()
+    ;
+  operator ==(dynamic dynamic) → core::bool* {
+    core::print("D.==");
+    return true;
+  }
+  method x() → void {
+    core::print("D.x");
+  }
+}
+class Foo extends mix::_Foo&B&D {
+  synthetic constructor •() → mix::Foo*
+    : super mix::_Foo&B&D::•()
+    ;
+}
+abstract class B extends core::Object implements mix::C {
+  synthetic constructor •() → mix::B*
+    : super core::Object::•()
+    ;
+  operator ==(dynamic dynamic) → core::bool* {
+    core::print("B.==");
+    return true;
+  }
+  method x() → void {
+    core::print("B.x");
+  }
+  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 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 C extends core::Object {
+  synthetic constructor •() → mix::C*
+    : super core::Object::•()
+    ;
+  abstract member-signature operator ==(dynamic other) → core::bool*; -> 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 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 D extends core::Object implements mix::C {
+  synthetic constructor •() → mix::D*
+    : super core::Object::•()
+    ;
+  operator ==(dynamic dynamic) → core::bool* {
+    core::print("D.==");
+    return true;
+  }
+  method x() → void {
+    core::print("D.x");
+  }
+  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 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
+}
+
+library;
+import self as mix2;
+import "dart:core" as core;
+
+abstract class _Foo&B&D extends mix2::B implements mix2::D /*isAnonymousMixin,isEliminatedMixin*/  {
+  synthetic constructor •() → mix2::_Foo&B&D*
+    : super mix2::B::•()
+    ;
+  operator ==(dynamic dynamic) → core::bool* {
+    core::print("D.==");
+    return true;
+  }
+  method x() → void {
+    core::print("D.x");
+  }
+}
+class Foo extends mix2::_Foo&B&D {
+  synthetic constructor •() → mix2::Foo*
+    : super mix2::_Foo&B&D::•()
+    ;
+}
+abstract class B extends core::Object implements mix2::C {
+  synthetic constructor •() → mix2::B*
+    : super core::Object::•()
+    ;
+  operator ==(dynamic dynamic) → core::bool* {
+    core::print("B.==");
+    return true;
+  }
+  method x() → void {
+    core::print("B.x");
+  }
+  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 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 C extends core::Object {
+  synthetic constructor •() → mix2::C*
+    : super core::Object::•()
+    ;
+  abstract member-signature operator ==(dynamic other) → core::bool*; -> 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 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 D extends core::Object implements mix2::C {
+  synthetic constructor •() → mix2::D*
+    : super core::Object::•()
+    ;
+  operator ==(dynamic dynamic) → core::bool* {
+    core::print("D.==");
+    return true;
+  }
+  method x() → void {
+    core::print("D.x");
+  }
+  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 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
+}
diff --git a/pkg/front_end/testcases/general/with_dependencies/mixin_from_dill/mixin_from_dill_lib1.dart b/pkg/front_end/testcases/general/with_dependencies/mixin_from_dill/mixin_from_dill_lib1.dart
index 31bba91..f123e40 100644
--- a/pkg/front_end/testcases/general/with_dependencies/mixin_from_dill/mixin_from_dill_lib1.dart
+++ b/pkg/front_end/testcases/general/with_dependencies/mixin_from_dill/mixin_from_dill_lib1.dart
@@ -1,7 +1,9 @@
 // Copyright (c) 2020, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
+
 // @dart=2.9
+
 class Foo extends B with D {}
 abstract class B implements C {
   bool operator==(dynamic) {
diff --git a/pkg/front_end/testcases/general/with_dependencies/mixin_from_dill/mixin_from_dill_lib2.dart b/pkg/front_end/testcases/general/with_dependencies/mixin_from_dill/mixin_from_dill_lib2.dart
index 31bba91..f123e40 100644
--- a/pkg/front_end/testcases/general/with_dependencies/mixin_from_dill/mixin_from_dill_lib2.dart
+++ b/pkg/front_end/testcases/general/with_dependencies/mixin_from_dill/mixin_from_dill_lib2.dart
@@ -1,7 +1,9 @@
 // Copyright (c) 2020, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
+
 // @dart=2.9
+
 class Foo extends B with D {}
 abstract class B implements C {
   bool operator==(dynamic) {
diff --git a/runtime/tools/run_clang_tidy.dart b/runtime/tools/run_clang_tidy.dart
index 0d9831a..d85f7c3 100644
--- a/runtime/tools/run_clang_tidy.dart
+++ b/runtime/tools/run_clang_tidy.dart
@@ -23,7 +23,7 @@
     '-DTARGET_OS_LINUX',
     '-DTESTING',
     '-x',
-    'c++',
+    'c++17',
   ];
   return flags;
 }
diff --git a/runtime/vm/class_id.h b/runtime/vm/class_id.h
index f59c94b..cb1b9f0 100644
--- a/runtime/vm/class_id.h
+++ b/runtime/vm/class_id.h
@@ -228,7 +228,6 @@
 bool IsIntegerClassId(intptr_t index);
 bool IsStringClassId(intptr_t index);
 bool IsOneByteStringClassId(intptr_t index);
-bool IsTwoByteStringClassId(intptr_t index);
 bool IsExternalStringClassId(intptr_t index);
 bool IsBuiltinListClassId(intptr_t index);
 bool IsTypeClassId(intptr_t index);
@@ -236,19 +235,11 @@
 bool IsTypedDataClassId(intptr_t index);
 bool IsTypedDataViewClassId(intptr_t index);
 bool IsExternalTypedDataClassId(intptr_t index);
-bool IsFfiNativeTypeTypeClassId(intptr_t index);
 bool IsFfiPointerClassId(intptr_t index);
 bool IsFfiTypeClassId(intptr_t index);
-bool IsFfiTypeIntClassId(intptr_t index);
-bool IsFfiTypeDoubleClassId(intptr_t index);
-bool IsFfiTypeVoidClassId(intptr_t index);
-bool IsFfiTypeNativeFunctionClassId(intptr_t index);
 bool IsFfiDynamicLibraryClassId(intptr_t index);
-bool IsFfiClassId(intptr_t index);
 bool IsInternalVMdefinedClassId(intptr_t index);
-bool IsVariableSizeClassId(intptr_t index);
 bool IsImplicitFieldClassId(intptr_t index);
-intptr_t NumberOfTypedDataClasses();
 
 inline bool IsErrorClassId(intptr_t index) {
   // Make sure this function is updated when new Error types are added.
@@ -272,39 +263,21 @@
   return (index >= kIntegerCid && index <= kMintCid);
 }
 
+// Make sure this check is updated when new StringCid types are added.
+COMPILE_ASSERT(kOneByteStringCid == kStringCid + 1 &&
+               kTwoByteStringCid == kStringCid + 2 &&
+               kExternalOneByteStringCid == kStringCid + 3 &&
+               kExternalTwoByteStringCid == kStringCid + 4);
+
 inline bool IsStringClassId(intptr_t index) {
-  // Make sure this function is updated when new StringCid types are added.
-  COMPILE_ASSERT(kOneByteStringCid == kStringCid + 1 &&
-                 kTwoByteStringCid == kStringCid + 2 &&
-                 kExternalOneByteStringCid == kStringCid + 3 &&
-                 kExternalTwoByteStringCid == kStringCid + 4);
   return (index >= kStringCid && index <= kExternalTwoByteStringCid);
 }
 
 inline bool IsOneByteStringClassId(intptr_t index) {
-  // Make sure this function is updated when new StringCid types are added.
-  COMPILE_ASSERT(kOneByteStringCid == kStringCid + 1 &&
-                 kTwoByteStringCid == kStringCid + 2 &&
-                 kExternalOneByteStringCid == kStringCid + 3 &&
-                 kExternalTwoByteStringCid == kStringCid + 4);
   return (index == kOneByteStringCid || index == kExternalOneByteStringCid);
 }
 
-inline bool IsTwoByteStringClassId(intptr_t index) {
-  // Make sure this function is updated when new StringCid types are added.
-  COMPILE_ASSERT(kOneByteStringCid == kStringCid + 1 &&
-                 kTwoByteStringCid == kStringCid + 2 &&
-                 kExternalOneByteStringCid == kStringCid + 3 &&
-                 kExternalTwoByteStringCid == kStringCid + 4);
-  return (index == kTwoByteStringCid || index == kExternalTwoByteStringCid);
-}
-
 inline bool IsExternalStringClassId(intptr_t index) {
-  // Make sure this function is updated when new StringCid types are added.
-  COMPILE_ASSERT(kOneByteStringCid == kStringCid + 1 &&
-                 kTwoByteStringCid == kStringCid + 2 &&
-                 kExternalOneByteStringCid == kStringCid + 3 &&
-                 kExternalTwoByteStringCid == kStringCid + 4);
   return (index == kExternalOneByteStringCid ||
           index == kExternalTwoByteStringCid);
 }
@@ -354,10 +327,6 @@
                                            3) == kTypedDataCidRemainderExternal;
 }
 
-inline bool IsFfiNativeTypeTypeClassId(intptr_t index) {
-  return index == kFfiNativeTypeCid;
-}
-
 inline bool IsFfiTypeClassId(intptr_t index) {
   switch (index) {
     case kFfiPointerCid:
@@ -384,30 +353,10 @@
   UNREACHABLE();
 }
 
-inline bool IsFfiTypeIntClassId(intptr_t index) {
-  return (index >= kFfiInt8Cid && index <= kFfiIntPtrCid);
-}
-
-inline bool IsFfiTypeDoubleClassId(intptr_t index) {
-  return (index >= kFfiFloatCid && index <= kFfiDoubleCid);
-}
-
 inline bool IsFfiPointerClassId(intptr_t index) {
   return index == kFfiPointerCid;
 }
 
-inline bool IsFfiTypeVoidClassId(intptr_t index) {
-  return index == kFfiVoidCid;
-}
-
-inline bool IsFfiTypeNativeFunctionClassId(intptr_t index) {
-  return index == kFfiNativeFunctionCid;
-}
-
-inline bool IsFfiClassId(intptr_t index) {
-  return (index >= kFfiPointerCid && index <= kFfiVoidCid);
-}
-
 inline bool IsFfiDynamicLibraryClassId(intptr_t index) {
   return index == kFfiDynamicLibraryCid;
 }
@@ -416,21 +365,6 @@
   return ((index < kNumPredefinedCids) && !IsImplicitFieldClassId(index));
 }
 
-inline bool IsVariableSizeClassId(intptr_t index) {
-  return (index == kArrayCid) || (index == kImmutableArrayCid) ||
-         IsOneByteStringClassId(index) || IsTwoByteStringClassId(index) ||
-         IsTypedDataClassId(index) || (index == kContextCid) ||
-         (index == kTypeArgumentsCid) || (index == kInstructionsCid) ||
-         (index == kInstructionsSectionCid) ||
-         (index == kInstructionsTableCid) || (index == kObjectPoolCid) ||
-         (index == kPcDescriptorsCid) || (index == kCodeSourceMapCid) ||
-         (index == kCompressedStackMapsCid) ||
-         (index == kLocalVarDescriptorsCid) ||
-         (index == kExceptionHandlersCid) || (index == kCodeCid) ||
-         (index == kContextScopeCid) || (index == kInstanceCid) ||
-         (index == kRegExpCid);
-}
-
 // This is a set of classes that are not Dart classes whose representation
 // is defined by the VM but are used in the VM code by computing the
 // implicit field offsets of the various fields in the dart object.
@@ -438,35 +372,30 @@
   return index == kByteBufferCid;
 }
 
-inline intptr_t NumberOfTypedDataClasses() {
-  // Make sure this is updated when new TypedData types are added.
+// Make sure the following checks are updated when adding new TypedData types.
 
-  // Ensure that each typed data type comes in internal/view/external variants
-  // next to each other.
-  COMPILE_ASSERT(kTypedDataInt8ArrayCid + 1 == kTypedDataInt8ArrayViewCid);
-  COMPILE_ASSERT(kTypedDataInt8ArrayCid + 2 == kExternalTypedDataInt8ArrayCid);
+// Ensure that each typed data type comes in internal/view/external variants
+// next to each other.
+COMPILE_ASSERT(kTypedDataInt8ArrayCid + 1 == kTypedDataInt8ArrayViewCid);
+COMPILE_ASSERT(kTypedDataInt8ArrayCid + 2 == kExternalTypedDataInt8ArrayCid);
 
-  // Ensure the order of the typed data members in 3-step.
-  COMPILE_ASSERT(kTypedDataInt8ArrayCid + 1 * 3 == kTypedDataUint8ArrayCid);
-  COMPILE_ASSERT(kTypedDataInt8ArrayCid + 2 * 3 ==
-                 kTypedDataUint8ClampedArrayCid);
-  COMPILE_ASSERT(kTypedDataInt8ArrayCid + 3 * 3 == kTypedDataInt16ArrayCid);
-  COMPILE_ASSERT(kTypedDataInt8ArrayCid + 4 * 3 == kTypedDataUint16ArrayCid);
-  COMPILE_ASSERT(kTypedDataInt8ArrayCid + 5 * 3 == kTypedDataInt32ArrayCid);
-  COMPILE_ASSERT(kTypedDataInt8ArrayCid + 6 * 3 == kTypedDataUint32ArrayCid);
-  COMPILE_ASSERT(kTypedDataInt8ArrayCid + 7 * 3 == kTypedDataInt64ArrayCid);
-  COMPILE_ASSERT(kTypedDataInt8ArrayCid + 8 * 3 == kTypedDataUint64ArrayCid);
-  COMPILE_ASSERT(kTypedDataInt8ArrayCid + 9 * 3 == kTypedDataFloat32ArrayCid);
-  COMPILE_ASSERT(kTypedDataInt8ArrayCid + 10 * 3 == kTypedDataFloat64ArrayCid);
-  COMPILE_ASSERT(kTypedDataInt8ArrayCid + 11 * 3 ==
-                 kTypedDataFloat32x4ArrayCid);
-  COMPILE_ASSERT(kTypedDataInt8ArrayCid + 12 * 3 == kTypedDataInt32x4ArrayCid);
-  COMPILE_ASSERT(kTypedDataInt8ArrayCid + 13 * 3 ==
-                 kTypedDataFloat64x2ArrayCid);
-  COMPILE_ASSERT(kTypedDataInt8ArrayCid + 14 * 3 == kByteDataViewCid);
-  COMPILE_ASSERT(kByteBufferCid + 1 == kNullCid);
-  return (kNullCid - kTypedDataInt8ArrayCid);
-}
+// Ensure the order of the typed data members in 3-step.
+COMPILE_ASSERT(kTypedDataInt8ArrayCid + 1 * 3 == kTypedDataUint8ArrayCid);
+COMPILE_ASSERT(kTypedDataInt8ArrayCid + 2 * 3 ==
+               kTypedDataUint8ClampedArrayCid);
+COMPILE_ASSERT(kTypedDataInt8ArrayCid + 3 * 3 == kTypedDataInt16ArrayCid);
+COMPILE_ASSERT(kTypedDataInt8ArrayCid + 4 * 3 == kTypedDataUint16ArrayCid);
+COMPILE_ASSERT(kTypedDataInt8ArrayCid + 5 * 3 == kTypedDataInt32ArrayCid);
+COMPILE_ASSERT(kTypedDataInt8ArrayCid + 6 * 3 == kTypedDataUint32ArrayCid);
+COMPILE_ASSERT(kTypedDataInt8ArrayCid + 7 * 3 == kTypedDataInt64ArrayCid);
+COMPILE_ASSERT(kTypedDataInt8ArrayCid + 8 * 3 == kTypedDataUint64ArrayCid);
+COMPILE_ASSERT(kTypedDataInt8ArrayCid + 9 * 3 == kTypedDataFloat32ArrayCid);
+COMPILE_ASSERT(kTypedDataInt8ArrayCid + 10 * 3 == kTypedDataFloat64ArrayCid);
+COMPILE_ASSERT(kTypedDataInt8ArrayCid + 11 * 3 == kTypedDataFloat32x4ArrayCid);
+COMPILE_ASSERT(kTypedDataInt8ArrayCid + 12 * 3 == kTypedDataInt32x4ArrayCid);
+COMPILE_ASSERT(kTypedDataInt8ArrayCid + 13 * 3 == kTypedDataFloat64x2ArrayCid);
+COMPILE_ASSERT(kTypedDataInt8ArrayCid + 14 * 3 == kByteDataViewCid);
+COMPILE_ASSERT(kByteBufferCid + 1 == kNullCid);
 
 }  // namespace dart
 
diff --git a/runtime/vm/class_table.cc b/runtime/vm/class_table.cc
index 3f1274c..dbf8f22 100644
--- a/runtime/vm/class_table.cc
+++ b/runtime/vm/class_table.cc
@@ -540,10 +540,6 @@
   }
 }
 
-bool SharedClassTable::ShouldUpdateSizeForClassId(intptr_t cid) {
-  return !IsVariableSizeClassId(cid);
-}
-
 intptr_t SharedClassTable::ClassOffsetFor(intptr_t cid) {
   return cid * sizeof(uint8_t);  // NOLINT
 }
diff --git a/runtime/vm/class_table.h b/runtime/vm/class_table.h
index 9f23820..9d5ad54 100644
--- a/runtime/vm/class_table.h
+++ b/runtime/vm/class_table.h
@@ -216,8 +216,6 @@
   friend class Scavenger;
   friend class ScavengerWeakVisitor;
 
-  static bool ShouldUpdateSizeForClassId(intptr_t cid);
-
 #ifndef PRODUCT
   // Copy-on-write is used for trace_allocation_table_, with old copies stored
   // in old_tables_.
diff --git a/runtime/vm/clustered_snapshot.cc b/runtime/vm/clustered_snapshot.cc
index 585c296..12f1e10 100644
--- a/runtime/vm/clustered_snapshot.cc
+++ b/runtime/vm/clustered_snapshot.cc
@@ -130,24 +130,6 @@
   CodeRelocator::Relocate(thread, code_objects, image_writer_commands, is_vm);
 }
 
-class CodePtrKeyValueTrait {
- public:
-  // Typedefs needed for the DirectChainedHashMap template.
-  typedef const CodePtr Key;
-  typedef const CodePtr Value;
-  typedef CodePtr Pair;
-
-  static Key KeyOf(Pair kv) { return kv; }
-  static Value ValueOf(Pair kv) { return kv; }
-  static inline intptr_t Hashcode(Key key) {
-    return static_cast<intptr_t>(key);
-  }
-
-  static inline bool IsKeyEqual(Pair pair, Key key) { return pair == key; }
-};
-
-typedef DirectChainedHashMap<CodePtrKeyValueTrait> RawCodeSet;
-
 #endif  // defined(DART_PRECOMPILER) && !defined(TARGET_ARCH_IA32)
 
 static ObjectPtr AllocateUninitialized(PageSpace* old_space, intptr_t size) {
diff --git a/tools/VERSION b/tools/VERSION
index 10f522a..18aba60 100644
--- a/tools/VERSION
+++ b/tools/VERSION
@@ -27,5 +27,5 @@
 MAJOR 2
 MINOR 13
 PATCH 0
-PRERELEASE 235
+PRERELEASE 236
 PRERELEASE_PATCH 0
\ No newline at end of file
diff --git a/tools/bots/flutter/analyze_flutter_engine.sh b/tools/bots/flutter/analyze_flutter_engine.sh
index eac0e39..46f0a82 100755
--- a/tools/bots/flutter/analyze_flutter_engine.sh
+++ b/tools/bots/flutter/analyze_flutter_engine.sh
@@ -5,7 +5,7 @@
 
 # Analyze Dart code in the flutter/engine repo.
 
-set -e
+set -ex
 
 checkout=$(pwd)
 dart=$checkout/out/ReleaseX64/dart-sdk/bin/dart
diff --git a/tools/bots/flutter/analyze_flutter_flutter.sh b/tools/bots/flutter/analyze_flutter_flutter.sh
index adca5cb..4ec83ad 100755
--- a/tools/bots/flutter/analyze_flutter_flutter.sh
+++ b/tools/bots/flutter/analyze_flutter_flutter.sh
@@ -5,7 +5,7 @@
 
 # Analyze Dart code in the flutter/flutter repo.
 
-set -e
+set -ex
 
 checkout=$(pwd)
 dart=$checkout/out/ReleaseX64/dart-sdk/bin/dart
diff --git a/tools/bots/flutter/compile_flutter.sh b/tools/bots/flutter/compile_flutter.sh
index 4e8a59f..35c3e81 100755
--- a/tools/bots/flutter/compile_flutter.sh
+++ b/tools/bots/flutter/compile_flutter.sh
@@ -5,7 +5,7 @@
 
 # Compile flutter tests with a locally built SDK.
 
-set -e
+set -ex
 
 prepareOnly=false
 leakTest=false