[cfe] Report error when extending/impl/mixing in sealed classes outside of its library.

Change-Id: I8034cba69ca249c2727dea9641c3076788c6a854
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/271164
Reviewed-by: Johnni Winther <johnniwinther@google.com>
Commit-Queue: Kallen Tu <kallentu@google.com>

pkg/_fe_analyzer_shared/lib/src/messages/codes_generated.dart

@@ -10659,6 +10659,60 @@ Message _withArgumentsSdkSummaryNotFound(Uri uri_) {
       arguments: {'uri': uri_});
 }
 
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Template<
+    Message Function(
+        String
+            name)> templateSealedClassSubtypeOutsideOfLibrary = const Template<
+        Message Function(String name)>(
+    problemMessageTemplate:
+        r"""Sealed class '#name' can't be extended, implemented, or mixed in outside of its library.""",
+    withArguments: _withArgumentsSealedClassSubtypeOutsideOfLibrary);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Code<Message Function(String name)>
+    codeSealedClassSubtypeOutsideOfLibrary =
+    const Code<Message Function(String name)>(
+  "SealedClassSubtypeOutsideOfLibrary",
+);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+Message _withArgumentsSealedClassSubtypeOutsideOfLibrary(String name) {
+  if (name.isEmpty) throw 'No name provided';
+  name = demangleMixinApplicationName(name);
+  return new Message(codeSealedClassSubtypeOutsideOfLibrary,
+      problemMessage:
+          """Sealed class '${name}' can't be extended, implemented, or mixed in outside of its library.""",
+      arguments: {'name': name});
+}
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Template<
+    Message Function(
+        String
+            name)> templateSealedMixinSubtypeOutsideOfLibrary = const Template<
+        Message Function(String name)>(
+    problemMessageTemplate:
+        r"""Sealed mixin '#name' can't be mixed in outside of its library.""",
+    withArguments: _withArgumentsSealedMixinSubtypeOutsideOfLibrary);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Code<Message Function(String name)>
+    codeSealedMixinSubtypeOutsideOfLibrary =
+    const Code<Message Function(String name)>(
+  "SealedMixinSubtypeOutsideOfLibrary",
+);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+Message _withArgumentsSealedMixinSubtypeOutsideOfLibrary(String name) {
+  if (name.isEmpty) throw 'No name provided';
+  name = demangleMixinApplicationName(name);
+  return new Message(codeSealedMixinSubtypeOutsideOfLibrary,
+      problemMessage:
+          """Sealed mixin '${name}' can't be mixed in outside of its library.""",
+      arguments: {'name': name});
+}
+
 // DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
 const Code<Null> codeSetLiteralTooManyTypeArguments =
     messageSetLiteralTooManyTypeArguments;

pkg/front_end/lib/src/fasta/builder/class_builder.dart

@@ -74,6 +74,8 @@ abstract class ClassBuilder implements DeclarationBuilder {
 
   bool get isMixin;
 
+  bool get isMixinDeclaration;
+
   bool get isMixinApplication;
 
   bool get isAnonymousMixinApplication;

pkg/front_end/lib/src/fasta/dill/dill_class_builder.dart

@@ -57,6 +57,9 @@ class DillClassBuilder extends ClassBuilderImpl {
   @override
   bool get isMacro => cls.isMacro;
 
+  @override
+  bool get isMixinDeclaration => cls.isMixinDeclaration;
+
   @override
   bool get isSealed => cls.isSealed;
 

pkg/front_end/lib/src/fasta/source/source_class_builder.dart

@@ -103,8 +103,6 @@ class SourceClassBuilder extends ClassBuilderImpl
   @override
   TypeBuilder? mixedInTypeBuilder;
 
-  bool isMixinDeclaration;
-
   final IndexedClass? referencesFromIndexed;
 
   @override
@@ -116,6 +114,9 @@ class SourceClassBuilder extends ClassBuilderImpl
   @override
   final bool isAugmentation;
 
+  @override
+  bool isMixinDeclaration;
+
   bool? _isConflictingAugmentationMember;
 
   /// Returns `true` if this class is a class declared in an augmentation

pkg/front_end/lib/src/fasta/source/source_loader.dart

@@ -2069,6 +2069,22 @@ severity: $severity
               cls.charOffset,
               noLength);
         }
+      } else if (supertype is ClassBuilder &&
+          supertype.isSealed &&
+          supertype.libraryBuilder.origin != cls.libraryBuilder.origin) {
+        if (supertype.isMixinDeclaration) {
+          cls.addProblem(
+              templateSealedMixinSubtypeOutsideOfLibrary
+                  .withArguments(supertype.fullNameForErrors),
+              cls.charOffset,
+              noLength);
+        } else {
+          cls.addProblem(
+              templateSealedClassSubtypeOutsideOfLibrary
+                  .withArguments(supertype.fullNameForErrors),
+              cls.charOffset,
+              noLength);
+        }
       }
     }
 

pkg/front_end/messages.status

@@ -861,6 +861,10 @@ SdkSpecificationNotFound/analyzerCode: Fail
 SdkSpecificationNotFound/example: Fail
 SdkSummaryNotFound/analyzerCode: Fail
 SdkSummaryNotFound/example: Fail
+SealedClassSubtypeOutsideOfLibrary/analyzerCode: Fail
+SealedClassSubtypeOutsideOfLibrary/part_wrapped_script: Fail # Uses imports
+SealedMixinSubtypeOutsideOfLibrary/analyzerCode: Fail
+SealedMixinSubtypeOutsideOfLibrary/part_wrapped_script: Fail # Uses imports
 SetLiteralTooManyTypeArguments/analyzerCode: Fail
 SetLiteralTooManyTypeArguments/example: Fail
 SetOrMapLiteralTooManyTypeArguments/analyzerCode: Fail

pkg/front_end/messages.yaml

@@ -5997,3 +5997,23 @@ InheritedRestrictedMemberOfEnumImplementer:
   script: |
     abstract class A { int get hashCode => 0; }
     abstract class B extends A implements Enum {}
+
+SealedClassSubtypeOutsideOfLibrary:
+  problemMessage: "Sealed class '#name' can't be extended, implemented, or mixed in outside of its library."
+  experiments: sealed-class
+  script:
+    main.dart:
+      import 'lib.dart';
+      class B extends A {}
+    lib.dart:
+      sealed class A {}
+
+SealedMixinSubtypeOutsideOfLibrary:
+  problemMessage: "Sealed mixin '#name' can't be mixed in outside of its library."
+  experiments: sealed-class
+  script:
+    main.dart:
+      import 'lib.dart';
+      class B with M {}
+    lib.dart:
+      sealed mixin M {}

pkg/front_end/testcases/sealed_class/extends_implements_with/main.dart

@@ -0,0 +1,11 @@
+// Copyright (c) 2022, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'main_lib.dart';
+
+class Class1 extends Sealed {}
+
+class Class2 implements Sealed {}
+
+class Class3 with Sealed {}

pkg/front_end/testcases/sealed_class/extends_implements_with/main.dart.strong.expect

@@ -0,0 +1,52 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/sealed_class/extends_implements_with/main.dart:7:7: Error: Sealed class 'Sealed' can't be extended, implemented, or mixed in outside of its library.
+// class Class1 extends Sealed {}
+//       ^
+//
+// pkg/front_end/testcases/sealed_class/extends_implements_with/main.dart:9:7: Error: Sealed class 'Sealed' can't be extended, implemented, or mixed in outside of its library.
+// class Class2 implements Sealed {}
+//       ^
+//
+// pkg/front_end/testcases/sealed_class/extends_implements_with/main.dart:11:7: Error: Sealed class 'Sealed' can't be extended, implemented, or mixed in outside of its library.
+// class Class3 with Sealed {}
+//       ^
+//
+import self as self;
+import "main_lib.dart" as mai;
+import "dart:core" as core;
+
+import "org-dartlang-testcase:///main_lib.dart";
+
+class Class1 extends mai::Sealed {
+  synthetic constructor •() → self::Class1
+    : super mai::Sealed::•()
+    ;
+}
+class Class2 extends core::Object implements mai::Sealed {
+  synthetic constructor •() → self::Class2
+    : super core::Object::•()
+    ;
+}
+abstract class _Class3&Object&Sealed = core::Object with mai::Sealed /*isAnonymousMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_Class3&Object&Sealed
+    : super core::Object::•()
+    ;
+}
+class Class3 extends self::_Class3&Object&Sealed {
+  synthetic constructor •() → self::Class3
+    : super self::_Class3&Object&Sealed::•()
+    ;
+}
+
+library /*isNonNullableByDefault*/;
+import self as mai;
+import "dart:core" as core;
+
+abstract sealed class Sealed extends core::Object {
+  synthetic constructor •() → mai::Sealed
+    : super core::Object::•()
+    ;
+}

pkg/front_end/testcases/sealed_class/extends_implements_with/main.dart.strong.transformed.expect

@@ -0,0 +1,52 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/sealed_class/extends_implements_with/main.dart:7:7: Error: Sealed class 'Sealed' can't be extended, implemented, or mixed in outside of its library.
+// class Class1 extends Sealed {}
+//       ^
+//
+// pkg/front_end/testcases/sealed_class/extends_implements_with/main.dart:9:7: Error: Sealed class 'Sealed' can't be extended, implemented, or mixed in outside of its library.
+// class Class2 implements Sealed {}
+//       ^
+//
+// pkg/front_end/testcases/sealed_class/extends_implements_with/main.dart:11:7: Error: Sealed class 'Sealed' can't be extended, implemented, or mixed in outside of its library.
+// class Class3 with Sealed {}
+//       ^
+//
+import self as self;
+import "main_lib.dart" as mai;
+import "dart:core" as core;
+
+import "org-dartlang-testcase:///main_lib.dart";
+
+class Class1 extends mai::Sealed {
+  synthetic constructor •() → self::Class1
+    : super mai::Sealed::•()
+    ;
+}
+class Class2 extends core::Object implements mai::Sealed {
+  synthetic constructor •() → self::Class2
+    : super core::Object::•()
+    ;
+}
+abstract class _Class3&Object&Sealed extends core::Object implements mai::Sealed /*isAnonymousMixin,isEliminatedMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_Class3&Object&Sealed
+    : super core::Object::•()
+    ;
+}
+class Class3 extends self::_Class3&Object&Sealed {
+  synthetic constructor •() → self::Class3
+    : super self::_Class3&Object&Sealed::•()
+    ;
+}
+
+library /*isNonNullableByDefault*/;
+import self as mai;
+import "dart:core" as core;
+
+abstract sealed class Sealed extends core::Object {
+  synthetic constructor •() → mai::Sealed
+    : super core::Object::•()
+    ;
+}

pkg/front_end/testcases/sealed_class/extends_implements_with/main.dart.textual_outline.expect

@@ -0,0 +1,7 @@
+import 'main_lib.dart';
+
+class Class1 extends Sealed {}
+
+class Class2 implements Sealed {}
+
+class Class3 with Sealed {}

pkg/front_end/testcases/sealed_class/extends_implements_with/main.dart.textual_outline_modelled.expect

@@ -0,0 +1,7 @@
+import 'main_lib.dart';
+
+class Class1 extends Sealed {}
+
+class Class2 implements Sealed {}
+
+class Class3 with Sealed {}

pkg/front_end/testcases/sealed_class/extends_implements_with/main.dart.weak.expect

@@ -0,0 +1,52 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/sealed_class/extends_implements_with/main.dart:7:7: Error: Sealed class 'Sealed' can't be extended, implemented, or mixed in outside of its library.
+// class Class1 extends Sealed {}
+//       ^
+//
+// pkg/front_end/testcases/sealed_class/extends_implements_with/main.dart:9:7: Error: Sealed class 'Sealed' can't be extended, implemented, or mixed in outside of its library.
+// class Class2 implements Sealed {}
+//       ^
+//
+// pkg/front_end/testcases/sealed_class/extends_implements_with/main.dart:11:7: Error: Sealed class 'Sealed' can't be extended, implemented, or mixed in outside of its library.
+// class Class3 with Sealed {}
+//       ^
+//
+import self as self;
+import "main_lib.dart" as mai;
+import "dart:core" as core;
+
+import "org-dartlang-testcase:///main_lib.dart";
+
+class Class1 extends mai::Sealed {
+  synthetic constructor •() → self::Class1
+    : super mai::Sealed::•()
+    ;
+}
+class Class2 extends core::Object implements mai::Sealed {
+  synthetic constructor •() → self::Class2
+    : super core::Object::•()
+    ;
+}
+abstract class _Class3&Object&Sealed = core::Object with mai::Sealed /*isAnonymousMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_Class3&Object&Sealed
+    : super core::Object::•()
+    ;
+}
+class Class3 extends self::_Class3&Object&Sealed {
+  synthetic constructor •() → self::Class3
+    : super self::_Class3&Object&Sealed::•()
+    ;
+}
+
+library /*isNonNullableByDefault*/;
+import self as mai;
+import "dart:core" as core;
+
+abstract sealed class Sealed extends core::Object {
+  synthetic constructor •() → mai::Sealed
+    : super core::Object::•()
+    ;
+}

pkg/front_end/testcases/sealed_class/extends_implements_with/main.dart.weak.modular.expect

@@ -0,0 +1,42 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/sealed_class/extends_implements_with/main.dart:7:7: Error: Sealed class 'Sealed' can't be extended, implemented, or mixed in outside of its library.
+// class Class1 extends Sealed {}
+//       ^
+//
+// pkg/front_end/testcases/sealed_class/extends_implements_with/main.dart:9:7: Error: Sealed class 'Sealed' can't be extended, implemented, or mixed in outside of its library.
+// class Class2 implements Sealed {}
+//       ^
+//
+// pkg/front_end/testcases/sealed_class/extends_implements_with/main.dart:11:7: Error: Sealed class 'Sealed' can't be extended, implemented, or mixed in outside of its library.
+// class Class3 with Sealed {}
+//       ^
+//
+import self as self;
+import "main_lib.dart" as mai;
+import "dart:core" as core;
+
+import "org-dartlang-testcase:///main_lib.dart";
+
+class Class1 extends mai::Sealed {
+  synthetic constructor •() → self::Class1
+    : super mai::Sealed::•()
+    ;
+}
+class Class2 extends core::Object implements mai::Sealed {
+  synthetic constructor •() → self::Class2
+    : super core::Object::•()
+    ;
+}
+abstract class _Class3&Object&Sealed = core::Object with mai::Sealed /*isAnonymousMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_Class3&Object&Sealed
+    : super core::Object::•()
+    ;
+}
+class Class3 extends self::_Class3&Object&Sealed {
+  synthetic constructor •() → self::Class3
+    : super self::_Class3&Object&Sealed::•()
+    ;
+}

pkg/front_end/testcases/sealed_class/extends_implements_with/main.dart.weak.outline.expect

@@ -0,0 +1,48 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/sealed_class/extends_implements_with/main.dart:7:7: Error: Sealed class 'Sealed' can't be extended, implemented, or mixed in outside of its library.
+// class Class1 extends Sealed {}
+//       ^
+//
+// pkg/front_end/testcases/sealed_class/extends_implements_with/main.dart:9:7: Error: Sealed class 'Sealed' can't be extended, implemented, or mixed in outside of its library.
+// class Class2 implements Sealed {}
+//       ^
+//
+// pkg/front_end/testcases/sealed_class/extends_implements_with/main.dart:11:7: Error: Sealed class 'Sealed' can't be extended, implemented, or mixed in outside of its library.
+// class Class3 with Sealed {}
+//       ^
+//
+import self as self;
+import "main_lib.dart" as mai;
+import "dart:core" as core;
+
+import "org-dartlang-testcase:///main_lib.dart";
+
+class Class1 extends mai::Sealed {
+  synthetic constructor •() → self::Class1
+    ;
+}
+class Class2 extends core::Object implements mai::Sealed {
+  synthetic constructor •() → self::Class2
+    ;
+}
+abstract class _Class3&Object&Sealed = core::Object with mai::Sealed /*isAnonymousMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_Class3&Object&Sealed
+    : super core::Object::•()
+    ;
+}
+class Class3 extends self::_Class3&Object&Sealed {
+  synthetic constructor •() → self::Class3
+    ;
+}
+
+library /*isNonNullableByDefault*/;
+import self as mai;
+import "dart:core" as core;
+
+abstract sealed class Sealed extends core::Object {
+  synthetic constructor •() → mai::Sealed
+    ;
+}

pkg/front_end/testcases/sealed_class/extends_implements_with/main.dart.weak.transformed.expect

@@ -0,0 +1,52 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/sealed_class/extends_implements_with/main.dart:7:7: Error: Sealed class 'Sealed' can't be extended, implemented, or mixed in outside of its library.
+// class Class1 extends Sealed {}
+//       ^
+//
+// pkg/front_end/testcases/sealed_class/extends_implements_with/main.dart:9:7: Error: Sealed class 'Sealed' can't be extended, implemented, or mixed in outside of its library.
+// class Class2 implements Sealed {}
+//       ^
+//
+// pkg/front_end/testcases/sealed_class/extends_implements_with/main.dart:11:7: Error: Sealed class 'Sealed' can't be extended, implemented, or mixed in outside of its library.
+// class Class3 with Sealed {}
+//       ^
+//
+import self as self;
+import "main_lib.dart" as mai;
+import "dart:core" as core;
+
+import "org-dartlang-testcase:///main_lib.dart";
+
+class Class1 extends mai::Sealed {
+  synthetic constructor •() → self::Class1
+    : super mai::Sealed::•()
+    ;
+}
+class Class2 extends core::Object implements mai::Sealed {
+  synthetic constructor •() → self::Class2
+    : super core::Object::•()
+    ;
+}
+abstract class _Class3&Object&Sealed extends core::Object implements mai::Sealed /*isAnonymousMixin,isEliminatedMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_Class3&Object&Sealed
+    : super core::Object::•()
+    ;
+}
+class Class3 extends self::_Class3&Object&Sealed {
+  synthetic constructor •() → self::Class3
+    : super self::_Class3&Object&Sealed::•()
+    ;
+}
+
+library /*isNonNullableByDefault*/;
+import self as mai;
+import "dart:core" as core;
+
+abstract sealed class Sealed extends core::Object {
+  synthetic constructor •() → mai::Sealed
+    : super core::Object::•()
+    ;
+}

pkg/front_end/testcases/sealed_class/extends_implements_with/main_lib.dart

@@ -0,0 +1,5 @@
+// Copyright (c) 2022, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+sealed class Sealed {}

pkg/front_end/testcases/sealed_class/extends_implements_with/test.options

@@ -0,0 +1 @@
+main_lib.dart

pkg/front_end/testcases/sealed_class/mixin_with/main.dart

@@ -0,0 +1,7 @@
+// Copyright (c) 2022, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'main_lib.dart';
+
+class Class1 with Sealed {}

pkg/front_end/testcases/sealed_class/mixin_with/main.dart.strong.expect

@@ -0,0 +1,31 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/sealed_class/mixin_with/main.dart:7:7: Error: Sealed mixin 'Sealed' can't be mixed in outside of its library.
+// class Class1 with Sealed {}
+//       ^
+//
+import self as self;
+import "dart:core" as core;
+import "main_lib.dart" as mai;
+
+import "org-dartlang-testcase:///main_lib.dart";
+
+abstract class _Class1&Object&Sealed = core::Object with mai::Sealed /*isAnonymousMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_Class1&Object&Sealed
+    : super core::Object::•()
+    ;
+}
+class Class1 extends self::_Class1&Object&Sealed {
+  synthetic constructor •() → self::Class1
+    : super self::_Class1&Object&Sealed::•()
+    ;
+}
+
+library /*isNonNullableByDefault*/;
+import self as mai;
+import "dart:core" as core;
+
+abstract sealed class Sealed extends core::Object /*isMixinDeclaration*/  {
+}

pkg/front_end/testcases/sealed_class/mixin_with/main.dart.strong.transformed.expect

@@ -0,0 +1,31 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/sealed_class/mixin_with/main.dart:7:7: Error: Sealed mixin 'Sealed' can't be mixed in outside of its library.
+// class Class1 with Sealed {}
+//       ^
+//
+import self as self;
+import "dart:core" as core;
+import "main_lib.dart" as mai;
+
+import "org-dartlang-testcase:///main_lib.dart";
+
+abstract class _Class1&Object&Sealed extends core::Object implements mai::Sealed /*isAnonymousMixin,isEliminatedMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_Class1&Object&Sealed
+    : super core::Object::•()
+    ;
+}
+class Class1 extends self::_Class1&Object&Sealed {
+  synthetic constructor •() → self::Class1
+    : super self::_Class1&Object&Sealed::•()
+    ;
+}
+
+library /*isNonNullableByDefault*/;
+import self as mai;
+import "dart:core" as core;
+
+abstract sealed class Sealed extends core::Object /*isMixinDeclaration*/  {
+}

pkg/front_end/testcases/sealed_class/mixin_with/main.dart.textual_outline.expect

@@ -0,0 +1,3 @@
+import 'main_lib.dart';
+
+class Class1 with Sealed {}

pkg/front_end/testcases/sealed_class/mixin_with/main.dart.textual_outline_modelled.expect

@@ -0,0 +1,3 @@
+import 'main_lib.dart';
+
+class Class1 with Sealed {}

pkg/front_end/testcases/sealed_class/mixin_with/main.dart.weak.expect

@@ -0,0 +1,31 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/sealed_class/mixin_with/main.dart:7:7: Error: Sealed mixin 'Sealed' can't be mixed in outside of its library.
+// class Class1 with Sealed {}
+//       ^
+//
+import self as self;
+import "dart:core" as core;
+import "main_lib.dart" as mai;
+
+import "org-dartlang-testcase:///main_lib.dart";
+
+abstract class _Class1&Object&Sealed = core::Object with mai::Sealed /*isAnonymousMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_Class1&Object&Sealed
+    : super core::Object::•()
+    ;
+}
+class Class1 extends self::_Class1&Object&Sealed {
+  synthetic constructor •() → self::Class1
+    : super self::_Class1&Object&Sealed::•()
+    ;
+}
+
+library /*isNonNullableByDefault*/;
+import self as mai;
+import "dart:core" as core;
+
+abstract sealed class Sealed extends core::Object /*isMixinDeclaration*/  {
+}

pkg/front_end/testcases/sealed_class/mixin_with/main.dart.weak.modular.expect

@@ -0,0 +1,24 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/sealed_class/mixin_with/main.dart:7:7: Error: Sealed mixin 'Sealed' can't be mixed in outside of its library.
+// class Class1 with Sealed {}
+//       ^
+//
+import self as self;
+import "dart:core" as core;
+import "main_lib.dart" as mai;
+
+import "org-dartlang-testcase:///main_lib.dart";
+
+abstract class _Class1&Object&Sealed = core::Object with mai::Sealed /*isAnonymousMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_Class1&Object&Sealed
+    : super core::Object::•()
+    ;
+}
+class Class1 extends self::_Class1&Object&Sealed {
+  synthetic constructor •() → self::Class1
+    : super self::_Class1&Object&Sealed::•()
+    ;
+}

pkg/front_end/testcases/sealed_class/mixin_with/main.dart.weak.outline.expect

@@ -0,0 +1,30 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/sealed_class/mixin_with/main.dart:7:7: Error: Sealed mixin 'Sealed' can't be mixed in outside of its library.
+// class Class1 with Sealed {}
+//       ^
+//
+import self as self;
+import "dart:core" as core;
+import "main_lib.dart" as mai;
+
+import "org-dartlang-testcase:///main_lib.dart";
+
+abstract class _Class1&Object&Sealed = core::Object with mai::Sealed /*isAnonymousMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_Class1&Object&Sealed
+    : super core::Object::•()
+    ;
+}
+class Class1 extends self::_Class1&Object&Sealed {
+  synthetic constructor •() → self::Class1
+    ;
+}
+
+library /*isNonNullableByDefault*/;
+import self as mai;
+import "dart:core" as core;
+
+abstract sealed class Sealed extends core::Object /*isMixinDeclaration*/  {
+}

pkg/front_end/testcases/sealed_class/mixin_with/main.dart.weak.transformed.expect

@@ -0,0 +1,31 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/sealed_class/mixin_with/main.dart:7:7: Error: Sealed mixin 'Sealed' can't be mixed in outside of its library.
+// class Class1 with Sealed {}
+//       ^
+//
+import self as self;
+import "dart:core" as core;
+import "main_lib.dart" as mai;
+
+import "org-dartlang-testcase:///main_lib.dart";
+
+abstract class _Class1&Object&Sealed extends core::Object implements mai::Sealed /*isAnonymousMixin,isEliminatedMixin,hasConstConstructor*/  {
+  const synthetic constructor •() → self::_Class1&Object&Sealed
+    : super core::Object::•()
+    ;
+}
+class Class1 extends self::_Class1&Object&Sealed {
+  synthetic constructor •() → self::Class1
+    : super self::_Class1&Object&Sealed::•()
+    ;
+}
+
+library /*isNonNullableByDefault*/;
+import self as mai;
+import "dart:core" as core;
+
+abstract sealed class Sealed extends core::Object /*isMixinDeclaration*/  {
+}

pkg/front_end/testcases/sealed_class/mixin_with/main_lib.dart

@@ -0,0 +1,5 @@
+// Copyright (c) 2022, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+sealed mixin Sealed {}

pkg/front_end/testcases/sealed_class/mixin_with/test.options

@@ -0,0 +1 @@
+main_lib.dart

tests/language/sealed_class/sealed_class_as_mixin_error_test.dart

@@ -9,14 +9,14 @@
 import 'sealed_class_as_mixin_lib.dart';
 
 abstract class OutsideA with SealedClass {}
-// ^
+//             ^
 // [analyzer] unspecified
-// [cfe] unspecified
+// [cfe] Sealed class 'SealedClass' can't be extended, implemented, or mixed in outside of its library.
 
 class OutsideB with SealedClass {
-// ^
+//    ^
 // [analyzer] unspecified
-// [cfe] unspecified
+// [cfe] Sealed class 'SealedClass' can't be extended, implemented, or mixed in outside of its library.
   @override
   int foo = 2;
 
@@ -25,6 +25,6 @@ class OutsideB with SealedClass {
 }
 
 abstract class OutsideC = Object with SealedClass;
-// ^
+//             ^
 // [analyzer] unspecified
-// [cfe] unspecified
+// [cfe] Sealed class 'SealedClass' can't be extended, implemented, or mixed in outside of its library.

tests/language/sealed_class/sealed_class_extend_error_test.dart

@@ -9,14 +9,14 @@
 import 'sealed_class_extend_lib.dart';
 
 abstract class OutsideA extends SealedClass {}
-// ^
+//             ^
 // [analyzer] unspecified
-// [cfe] unspecified
+// [cfe] Sealed class 'SealedClass' can't be extended, implemented, or mixed in outside of its library.
 
 class OutsideB extends SealedClass {
-// ^
+//    ^
 // [analyzer] unspecified
-// [cfe] unspecified
+// [cfe] Sealed class 'SealedClass' can't be extended, implemented, or mixed in outside of its library.
   @override
   int foo = 2;
 

tests/language/sealed_class/sealed_class_implement_error_test.dart

@@ -9,14 +9,14 @@
 import "sealed_class_implement_lib.dart";
 
 abstract class OutsideA implements SealedClass {}
-// ^
+//             ^
 // [analyzer] unspecified
-// [cfe] unspecified
+// [cfe] Sealed class 'SealedClass' can't be extended, implemented, or mixed in outside of its library.
 
 class OutsideB implements SealedClass {
-// ^
+//    ^
 // [analyzer] unspecified
-// [cfe] unspecified
+// [cfe] Sealed class 'SealedClass' can't be extended, implemented, or mixed in outside of its library.
   @override
   int nonAbstractFoo = 2;
 

tests/language/sealed_class/sealed_mixin_with_error_test.dart

@@ -9,14 +9,14 @@
 import 'sealed_mixin_with_lib.dart';
 
 abstract class OutsideA with SealedMixin {}
-// ^
+//             ^
 // [analyzer] unspecified
-// [cfe] unspecified
+// [cfe] Sealed mixin 'SealedMixin' can't be mixed in outside of its library.
 
 class OutsideB with SealedMixin {
-// ^
+//    ^
 // [analyzer] unspecified
-// [cfe] unspecified
+// [cfe] Sealed mixin 'SealedMixin' can't be mixed in outside of its library.
   @override
   int foo = 2;
 
@@ -25,6 +25,6 @@ class OutsideB with SealedMixin {
 }
 
 abstract class OutsideC = Object with SealedMixin;
-// ^
+//             ^
 // [analyzer] unspecified
-// [cfe] unspecified
+// [cfe] Sealed mixin 'SealedMixin' can't be mixed in outside of its library.