[cfe] Report error when implementing a base class.

Change-Id: Iff3c31b4883d3d4fc4c392c6ac8207617ce65761
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/279648
Reviewed-by: Johnni Winther <johnniwinther@google.com>
Commit-Queue: Kallen Tu <kallentu@google.com>

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

@@ -340,6 +340,60 @@ const MessageCode messageAwaitNotAsync = const MessageCode("AwaitNotAsync",
     problemMessage:
         r"""'await' can only be used in 'async' or 'async*' methods.""");
 
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Template<
+    Message Function(
+        String
+            name)> templateBaseClassImplementedOutsideOfLibrary = const Template<
+        Message Function(String name)>(
+    problemMessageTemplate:
+        r"""The class '#name' can't be implemented outside of its library because it's a base class.""",
+    withArguments: _withArgumentsBaseClassImplementedOutsideOfLibrary);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Code<Message Function(String name)>
+    codeBaseClassImplementedOutsideOfLibrary =
+    const Code<Message Function(String name)>(
+  "BaseClassImplementedOutsideOfLibrary",
+);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+Message _withArgumentsBaseClassImplementedOutsideOfLibrary(String name) {
+  if (name.isEmpty) throw 'No name provided';
+  name = demangleMixinApplicationName(name);
+  return new Message(codeBaseClassImplementedOutsideOfLibrary,
+      problemMessage:
+          """The class '${name}' can't be implemented outside of its library because it's a base class.""",
+      arguments: {'name': name});
+}
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Template<
+    Message Function(
+        String
+            name)> templateBaseMixinImplementedOutsideOfLibrary = const Template<
+        Message Function(String name)>(
+    problemMessageTemplate:
+        r"""The mixin '#name' can't be implemented outside of its library because it's a base mixin.""",
+    withArguments: _withArgumentsBaseMixinImplementedOutsideOfLibrary);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+const Code<Message Function(String name)>
+    codeBaseMixinImplementedOutsideOfLibrary =
+    const Code<Message Function(String name)>(
+  "BaseMixinImplementedOutsideOfLibrary",
+);
+
+// DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
+Message _withArgumentsBaseMixinImplementedOutsideOfLibrary(String name) {
+  if (name.isEmpty) throw 'No name provided';
+  name = demangleMixinApplicationName(name);
+  return new Message(codeBaseMixinImplementedOutsideOfLibrary,
+      problemMessage:
+          """The mixin '${name}' can't be implemented outside of its library because it's a base mixin.""",
+      arguments: {'name': name});
+}
+
 // DO NOT EDIT. THIS FILE IS GENERATED. SEE TOP OF FILE.
 const Template<
     Message Function(

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

@@ -2097,8 +2097,35 @@ severity: $severity
                 cls.charOffset,
                 noLength);
           }
-        }
 
+          // Report an error for a class implementing a base class outside of
+          // its library.
+          List<TypeBuilder>? interfaceBuilders = cls.interfaceBuilders;
+          if (supertype.isBase && interfaceBuilders != null) {
+            for (TypeBuilder interfaceBuilder in interfaceBuilders) {
+              TypeDeclarationBuilder? builder = interfaceBuilder.declaration;
+              while (builder is TypeAliasBuilder) {
+                builder = builder.type.declaration;
+              }
+              if (builder == supertype) {
+                if (supertype.isMixinDeclaration) {
+                  cls.addProblem(
+                      templateBaseMixinImplementedOutsideOfLibrary
+                          .withArguments(supertype.fullNameForErrors),
+                      cls.charOffset,
+                      noLength);
+                } else {
+                  cls.addProblem(
+                      templateBaseClassImplementedOutsideOfLibrary
+                          .withArguments(supertype.fullNameForErrors),
+                      cls.charOffset,
+                      noLength);
+                }
+                break;
+              }
+            }
+          }
+        }
         // Report error for subtyping outside of sealed supertype's library.
         if (cls.libraryBuilder.libraryFeatures.sealedClass.isEnabled &&
             supertype.isSealed) {

pkg/front_end/messages.status

@@ -39,6 +39,10 @@ AwaitAsIdentifier/example: Fail
 AwaitInLateLocalInitializer/analyzerCode: Fail
 AwaitInLateLocalInitializer/example: Fail
 AwaitNotAsync/example: Fail
+BaseClassImplementedOutsideOfLibrary/analyzerCode: Fail
+BaseClassImplementedOutsideOfLibrary/part_wrapped_script: Fail # Uses imports
+BaseMixinImplementedOutsideOfLibrary/analyzerCode: Fail
+BaseMixinImplementedOutsideOfLibrary/part_wrapped_script: Fail # Uses imports
 BuiltInIdentifierAsType/example: Fail
 BuiltInIdentifierInDeclaration/example: Fail
 BytecodeLimitExceededTooManyArguments/analyzerCode: Fail

pkg/front_end/messages.yaml

@@ -6060,6 +6060,26 @@ CantUseClassAsMixin:
     lib.dart:
       class A {}
 
+BaseClassImplementedOutsideOfLibrary:
+  problemMessage: "The class '#name' can't be implemented outside of its library because it's a base class."
+  experiments: class-modifiers
+  script:
+    main.dart:
+      import 'lib.dart';
+      class B implements A {}
+    lib.dart:
+      base class A {}
+
+BaseMixinImplementedOutsideOfLibrary:
+  problemMessage: "The mixin '#name' can't be implemented outside of its library because it's a base mixin."
+  experiments: class-modifiers
+  script:
+    main.dart:
+      import 'lib.dart';
+      class B implements A {}
+    lib.dart:
+      base mixin A {}
+
 UnspecifiedGetterNameInObjectPattern:
   problemMessage: "The getter name is not specified explicitly, and the pattern is not a variable. Try specifying the getter name explicitly, or using a variable pattern."
   experiments: patterns

pkg/front_end/testcases/class_modifiers/base/outside_library/main.dart

@@ -0,0 +1,9 @@
+// Copyright (c) 2023, 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 ImplementsBaseClass implements A {}
+
+class ImplementsBaseMixin implements M {}

pkg/front_end/testcases/class_modifiers/base/outside_library/main.dart.strong.expect

@@ -0,0 +1,40 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/class_modifiers/base/outside_library/main.dart:7:7: Error: The class 'A' can't be implemented outside of its library because it's a base class.
+// class ImplementsBaseClass implements A {}
+//       ^
+//
+// pkg/front_end/testcases/class_modifiers/base/outside_library/main.dart:9:7: Error: The mixin 'M' can't be implemented outside of its library because it's a base mixin.
+// class ImplementsBaseMixin implements M {}
+//       ^
+//
+import self as self;
+import "dart:core" as core;
+import "main_lib.dart" as mai;
+
+import "org-dartlang-testcase:///main_lib.dart";
+
+class ImplementsBaseClass extends core::Object implements mai::A {
+  synthetic constructor •() → self::ImplementsBaseClass
+    : super core::Object::•()
+    ;
+}
+class ImplementsBaseMixin extends core::Object implements mai::M {
+  synthetic constructor •() → self::ImplementsBaseMixin
+    : super core::Object::•()
+    ;
+}
+
+library /*isNonNullableByDefault*/;
+import self as mai;
+import "dart:core" as core;
+
+base class A extends core::Object {
+  synthetic constructor •() → mai::A
+    : super core::Object::•()
+    ;
+}
+abstract base class M extends core::Object /*isMixinDeclaration*/  {
+}

pkg/front_end/testcases/class_modifiers/base/outside_library/main.dart.strong.transformed.expect

@@ -0,0 +1,40 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/class_modifiers/base/outside_library/main.dart:7:7: Error: The class 'A' can't be implemented outside of its library because it's a base class.
+// class ImplementsBaseClass implements A {}
+//       ^
+//
+// pkg/front_end/testcases/class_modifiers/base/outside_library/main.dart:9:7: Error: The mixin 'M' can't be implemented outside of its library because it's a base mixin.
+// class ImplementsBaseMixin implements M {}
+//       ^
+//
+import self as self;
+import "dart:core" as core;
+import "main_lib.dart" as mai;
+
+import "org-dartlang-testcase:///main_lib.dart";
+
+class ImplementsBaseClass extends core::Object implements mai::A {
+  synthetic constructor •() → self::ImplementsBaseClass
+    : super core::Object::•()
+    ;
+}
+class ImplementsBaseMixin extends core::Object implements mai::M {
+  synthetic constructor •() → self::ImplementsBaseMixin
+    : super core::Object::•()
+    ;
+}
+
+library /*isNonNullableByDefault*/;
+import self as mai;
+import "dart:core" as core;
+
+base class A extends core::Object {
+  synthetic constructor •() → mai::A
+    : super core::Object::•()
+    ;
+}
+abstract base class M extends core::Object /*isMixinDeclaration*/  {
+}

pkg/front_end/testcases/class_modifiers/base/outside_library/main.dart.textual_outline.expect

@@ -0,0 +1,5 @@
+import 'main_lib.dart';
+
+class ImplementsBaseClass implements A {}
+
+class ImplementsBaseMixin implements M {}

pkg/front_end/testcases/class_modifiers/base/outside_library/main.dart.textual_outline_modelled.expect

@@ -0,0 +1,5 @@
+import 'main_lib.dart';
+
+class ImplementsBaseClass implements A {}
+
+class ImplementsBaseMixin implements M {}

pkg/front_end/testcases/class_modifiers/base/outside_library/main.dart.weak.expect

@@ -0,0 +1,40 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/class_modifiers/base/outside_library/main.dart:7:7: Error: The class 'A' can't be implemented outside of its library because it's a base class.
+// class ImplementsBaseClass implements A {}
+//       ^
+//
+// pkg/front_end/testcases/class_modifiers/base/outside_library/main.dart:9:7: Error: The mixin 'M' can't be implemented outside of its library because it's a base mixin.
+// class ImplementsBaseMixin implements M {}
+//       ^
+//
+import self as self;
+import "dart:core" as core;
+import "main_lib.dart" as mai;
+
+import "org-dartlang-testcase:///main_lib.dart";
+
+class ImplementsBaseClass extends core::Object implements mai::A {
+  synthetic constructor •() → self::ImplementsBaseClass
+    : super core::Object::•()
+    ;
+}
+class ImplementsBaseMixin extends core::Object implements mai::M {
+  synthetic constructor •() → self::ImplementsBaseMixin
+    : super core::Object::•()
+    ;
+}
+
+library /*isNonNullableByDefault*/;
+import self as mai;
+import "dart:core" as core;
+
+base class A extends core::Object {
+  synthetic constructor •() → mai::A
+    : super core::Object::•()
+    ;
+}
+abstract base class M extends core::Object /*isMixinDeclaration*/  {
+}

pkg/front_end/testcases/class_modifiers/base/outside_library/main.dart.weak.modular.expect

@@ -0,0 +1,28 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/class_modifiers/base/outside_library/main.dart:7:7: Error: The class 'A' can't be implemented outside of its library because it's a base class.
+// class ImplementsBaseClass implements A {}
+//       ^
+//
+// pkg/front_end/testcases/class_modifiers/base/outside_library/main.dart:9:7: Error: The mixin 'M' can't be implemented outside of its library because it's a base mixin.
+// class ImplementsBaseMixin implements M {}
+//       ^
+//
+import self as self;
+import "dart:core" as core;
+import "main_lib.dart" as mai;
+
+import "org-dartlang-testcase:///main_lib.dart";
+
+class ImplementsBaseClass extends core::Object implements mai::A {
+  synthetic constructor •() → self::ImplementsBaseClass
+    : super core::Object::•()
+    ;
+}
+class ImplementsBaseMixin extends core::Object implements mai::M {
+  synthetic constructor •() → self::ImplementsBaseMixin
+    : super core::Object::•()
+    ;
+}

pkg/front_end/testcases/class_modifiers/base/outside_library/main.dart.weak.outline.expect

@@ -0,0 +1,37 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/class_modifiers/base/outside_library/main.dart:7:7: Error: The class 'A' can't be implemented outside of its library because it's a base class.
+// class ImplementsBaseClass implements A {}
+//       ^
+//
+// pkg/front_end/testcases/class_modifiers/base/outside_library/main.dart:9:7: Error: The mixin 'M' can't be implemented outside of its library because it's a base mixin.
+// class ImplementsBaseMixin implements M {}
+//       ^
+//
+import self as self;
+import "dart:core" as core;
+import "main_lib.dart" as mai;
+
+import "org-dartlang-testcase:///main_lib.dart";
+
+class ImplementsBaseClass extends core::Object implements mai::A {
+  synthetic constructor •() → self::ImplementsBaseClass
+    ;
+}
+class ImplementsBaseMixin extends core::Object implements mai::M {
+  synthetic constructor •() → self::ImplementsBaseMixin
+    ;
+}
+
+library /*isNonNullableByDefault*/;
+import self as mai;
+import "dart:core" as core;
+
+base class A extends core::Object {
+  synthetic constructor •() → mai::A
+    ;
+}
+abstract base class M extends core::Object /*isMixinDeclaration*/  {
+}

pkg/front_end/testcases/class_modifiers/base/outside_library/main.dart.weak.transformed.expect

@@ -0,0 +1,40 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/class_modifiers/base/outside_library/main.dart:7:7: Error: The class 'A' can't be implemented outside of its library because it's a base class.
+// class ImplementsBaseClass implements A {}
+//       ^
+//
+// pkg/front_end/testcases/class_modifiers/base/outside_library/main.dart:9:7: Error: The mixin 'M' can't be implemented outside of its library because it's a base mixin.
+// class ImplementsBaseMixin implements M {}
+//       ^
+//
+import self as self;
+import "dart:core" as core;
+import "main_lib.dart" as mai;
+
+import "org-dartlang-testcase:///main_lib.dart";
+
+class ImplementsBaseClass extends core::Object implements mai::A {
+  synthetic constructor •() → self::ImplementsBaseClass
+    : super core::Object::•()
+    ;
+}
+class ImplementsBaseMixin extends core::Object implements mai::M {
+  synthetic constructor •() → self::ImplementsBaseMixin
+    : super core::Object::•()
+    ;
+}
+
+library /*isNonNullableByDefault*/;
+import self as mai;
+import "dart:core" as core;
+
+base class A extends core::Object {
+  synthetic constructor •() → mai::A
+    : super core::Object::•()
+    ;
+}
+abstract base class M extends core::Object /*isMixinDeclaration*/  {
+}

pkg/front_end/testcases/class_modifiers/base/outside_library/main_lib.dart

@@ -0,0 +1,7 @@
+// Copyright (c) 2023, 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.
+
+base class A {}
+
+base mixin M {}

pkg/front_end/testcases/class_modifiers/base/outside_library/test.options

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

pkg/front_end/testcases/class_modifiers/base/typedef/main.dart

@@ -0,0 +1,21 @@
+// Copyright (c) 2023, 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 ImplementsBaseClassTypedef implements ATypeDef {}
+
+class ImplementsBaseClassTypedef2 implements ATypeDef2 {}
+
+class ImplementsBaseMixinTypeDef implements MTypeDef {}
+
+class ImplementsBaseMixinTypeDef2 implements MTypeDef2 {}
+
+typedef AOutsideTypedef = A;
+
+typedef MOutsideTypedef = M;
+
+class ImplementsBaseClassTypedefOutside implements AOutsideTypedef {}
+
+class ImplementsBaseMixinTypeDefOutside implements MOutsideTypedef {}

pkg/front_end/testcases/class_modifiers/base/typedef/main.dart.strong.expect

@@ -0,0 +1,82 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/class_modifiers/base/typedef/main.dart:7:7: Error: The class 'A' can't be implemented outside of its library because it's a base class.
+// class ImplementsBaseClassTypedef implements ATypeDef {}
+//       ^
+//
+// pkg/front_end/testcases/class_modifiers/base/typedef/main.dart:9:7: Error: The class 'A' can't be implemented outside of its library because it's a base class.
+// class ImplementsBaseClassTypedef2 implements ATypeDef2 {}
+//       ^
+//
+// pkg/front_end/testcases/class_modifiers/base/typedef/main.dart:11:7: Error: The mixin 'M' can't be implemented outside of its library because it's a base mixin.
+// class ImplementsBaseMixinTypeDef implements MTypeDef {}
+//       ^
+//
+// pkg/front_end/testcases/class_modifiers/base/typedef/main.dart:13:7: Error: The mixin 'M' can't be implemented outside of its library because it's a base mixin.
+// class ImplementsBaseMixinTypeDef2 implements MTypeDef2 {}
+//       ^
+//
+// pkg/front_end/testcases/class_modifiers/base/typedef/main.dart:19:7: Error: The class 'A' can't be implemented outside of its library because it's a base class.
+// class ImplementsBaseClassTypedefOutside implements AOutsideTypedef {}
+//       ^
+//
+// pkg/front_end/testcases/class_modifiers/base/typedef/main.dart:21:7: Error: The mixin 'M' can't be implemented outside of its library because it's a base mixin.
+// class ImplementsBaseMixinTypeDefOutside implements MOutsideTypedef {}
+//       ^
+//
+import self as self;
+import "main_lib.dart" as mai;
+import "dart:core" as core;
+
+import "org-dartlang-testcase:///main_lib.dart";
+
+typedef AOutsideTypedef = mai::A;
+typedef MOutsideTypedef = mai::M;
+class ImplementsBaseClassTypedef extends core::Object implements mai::A {
+  synthetic constructor •() → self::ImplementsBaseClassTypedef
+    : super core::Object::•()
+    ;
+}
+class ImplementsBaseClassTypedef2 extends core::Object implements mai::A {
+  synthetic constructor •() → self::ImplementsBaseClassTypedef2
+    : super core::Object::•()
+    ;
+}
+class ImplementsBaseMixinTypeDef extends core::Object implements mai::M {
+  synthetic constructor •() → self::ImplementsBaseMixinTypeDef
+    : super core::Object::•()
+    ;
+}
+class ImplementsBaseMixinTypeDef2 extends core::Object implements mai::M {
+  synthetic constructor •() → self::ImplementsBaseMixinTypeDef2
+    : super core::Object::•()
+    ;
+}
+class ImplementsBaseClassTypedefOutside extends core::Object implements mai::A {
+  synthetic constructor •() → self::ImplementsBaseClassTypedefOutside
+    : super core::Object::•()
+    ;
+}
+class ImplementsBaseMixinTypeDefOutside extends core::Object implements mai::M {
+  synthetic constructor •() → self::ImplementsBaseMixinTypeDefOutside
+    : super core::Object::•()
+    ;
+}
+
+library /*isNonNullableByDefault*/;
+import self as mai;
+import "dart:core" as core;
+
+typedef ATypeDef = mai::A;
+typedef ATypeDef2 = mai::A;
+typedef MTypeDef = mai::M;
+typedef MTypeDef2 = mai::M;
+base class A extends core::Object {
+  synthetic constructor •() → mai::A
+    : super core::Object::•()
+    ;
+}
+abstract base class M extends core::Object /*isMixinDeclaration*/  {
+}

pkg/front_end/testcases/class_modifiers/base/typedef/main.dart.strong.transformed.expect

@@ -0,0 +1,82 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/class_modifiers/base/typedef/main.dart:7:7: Error: The class 'A' can't be implemented outside of its library because it's a base class.
+// class ImplementsBaseClassTypedef implements ATypeDef {}
+//       ^
+//
+// pkg/front_end/testcases/class_modifiers/base/typedef/main.dart:9:7: Error: The class 'A' can't be implemented outside of its library because it's a base class.
+// class ImplementsBaseClassTypedef2 implements ATypeDef2 {}
+//       ^
+//
+// pkg/front_end/testcases/class_modifiers/base/typedef/main.dart:11:7: Error: The mixin 'M' can't be implemented outside of its library because it's a base mixin.
+// class ImplementsBaseMixinTypeDef implements MTypeDef {}
+//       ^
+//
+// pkg/front_end/testcases/class_modifiers/base/typedef/main.dart:13:7: Error: The mixin 'M' can't be implemented outside of its library because it's a base mixin.
+// class ImplementsBaseMixinTypeDef2 implements MTypeDef2 {}
+//       ^
+//
+// pkg/front_end/testcases/class_modifiers/base/typedef/main.dart:19:7: Error: The class 'A' can't be implemented outside of its library because it's a base class.
+// class ImplementsBaseClassTypedefOutside implements AOutsideTypedef {}
+//       ^
+//
+// pkg/front_end/testcases/class_modifiers/base/typedef/main.dart:21:7: Error: The mixin 'M' can't be implemented outside of its library because it's a base mixin.
+// class ImplementsBaseMixinTypeDefOutside implements MOutsideTypedef {}
+//       ^
+//
+import self as self;
+import "main_lib.dart" as mai;
+import "dart:core" as core;
+
+import "org-dartlang-testcase:///main_lib.dart";
+
+typedef AOutsideTypedef = mai::A;
+typedef MOutsideTypedef = mai::M;
+class ImplementsBaseClassTypedef extends core::Object implements mai::A {
+  synthetic constructor •() → self::ImplementsBaseClassTypedef
+    : super core::Object::•()
+    ;
+}
+class ImplementsBaseClassTypedef2 extends core::Object implements mai::A {
+  synthetic constructor •() → self::ImplementsBaseClassTypedef2
+    : super core::Object::•()
+    ;
+}
+class ImplementsBaseMixinTypeDef extends core::Object implements mai::M {
+  synthetic constructor •() → self::ImplementsBaseMixinTypeDef
+    : super core::Object::•()
+    ;
+}
+class ImplementsBaseMixinTypeDef2 extends core::Object implements mai::M {
+  synthetic constructor •() → self::ImplementsBaseMixinTypeDef2
+    : super core::Object::•()
+    ;
+}
+class ImplementsBaseClassTypedefOutside extends core::Object implements mai::A {
+  synthetic constructor •() → self::ImplementsBaseClassTypedefOutside
+    : super core::Object::•()
+    ;
+}
+class ImplementsBaseMixinTypeDefOutside extends core::Object implements mai::M {
+  synthetic constructor •() → self::ImplementsBaseMixinTypeDefOutside
+    : super core::Object::•()
+    ;
+}
+
+library /*isNonNullableByDefault*/;
+import self as mai;
+import "dart:core" as core;
+
+typedef ATypeDef = mai::A;
+typedef ATypeDef2 = mai::A;
+typedef MTypeDef = mai::M;
+typedef MTypeDef2 = mai::M;
+base class A extends core::Object {
+  synthetic constructor •() → mai::A
+    : super core::Object::•()
+    ;
+}
+abstract base class M extends core::Object /*isMixinDeclaration*/  {
+}

pkg/front_end/testcases/class_modifiers/base/typedef/main.dart.textual_outline.expect

@@ -0,0 +1,16 @@
+import 'main_lib.dart';
+
+class ImplementsBaseClassTypedef implements ATypeDef {}
+
+class ImplementsBaseClassTypedef2 implements ATypeDef2 {}
+
+class ImplementsBaseMixinTypeDef implements MTypeDef {}
+
+class ImplementsBaseMixinTypeDef2 implements MTypeDef2 {}
+
+typedef AOutsideTypedef = A;
+typedef MOutsideTypedef = M;
+
+class ImplementsBaseClassTypedefOutside implements AOutsideTypedef {}
+
+class ImplementsBaseMixinTypeDefOutside implements MOutsideTypedef {}

pkg/front_end/testcases/class_modifiers/base/typedef/main.dart.textual_outline_modelled.expect

@@ -0,0 +1,16 @@
+import 'main_lib.dart';
+
+class ImplementsBaseClassTypedef implements ATypeDef {}
+
+class ImplementsBaseClassTypedef2 implements ATypeDef2 {}
+
+class ImplementsBaseClassTypedefOutside implements AOutsideTypedef {}
+
+class ImplementsBaseMixinTypeDef implements MTypeDef {}
+
+class ImplementsBaseMixinTypeDef2 implements MTypeDef2 {}
+
+class ImplementsBaseMixinTypeDefOutside implements MOutsideTypedef {}
+
+typedef AOutsideTypedef = A;
+typedef MOutsideTypedef = M;

pkg/front_end/testcases/class_modifiers/base/typedef/main.dart.weak.expect

@@ -0,0 +1,82 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/class_modifiers/base/typedef/main.dart:7:7: Error: The class 'A' can't be implemented outside of its library because it's a base class.
+// class ImplementsBaseClassTypedef implements ATypeDef {}
+//       ^
+//
+// pkg/front_end/testcases/class_modifiers/base/typedef/main.dart:9:7: Error: The class 'A' can't be implemented outside of its library because it's a base class.
+// class ImplementsBaseClassTypedef2 implements ATypeDef2 {}
+//       ^
+//
+// pkg/front_end/testcases/class_modifiers/base/typedef/main.dart:11:7: Error: The mixin 'M' can't be implemented outside of its library because it's a base mixin.
+// class ImplementsBaseMixinTypeDef implements MTypeDef {}
+//       ^
+//
+// pkg/front_end/testcases/class_modifiers/base/typedef/main.dart:13:7: Error: The mixin 'M' can't be implemented outside of its library because it's a base mixin.
+// class ImplementsBaseMixinTypeDef2 implements MTypeDef2 {}
+//       ^
+//
+// pkg/front_end/testcases/class_modifiers/base/typedef/main.dart:19:7: Error: The class 'A' can't be implemented outside of its library because it's a base class.
+// class ImplementsBaseClassTypedefOutside implements AOutsideTypedef {}
+//       ^
+//
+// pkg/front_end/testcases/class_modifiers/base/typedef/main.dart:21:7: Error: The mixin 'M' can't be implemented outside of its library because it's a base mixin.
+// class ImplementsBaseMixinTypeDefOutside implements MOutsideTypedef {}
+//       ^
+//
+import self as self;
+import "main_lib.dart" as mai;
+import "dart:core" as core;
+
+import "org-dartlang-testcase:///main_lib.dart";
+
+typedef AOutsideTypedef = mai::A;
+typedef MOutsideTypedef = mai::M;
+class ImplementsBaseClassTypedef extends core::Object implements mai::A {
+  synthetic constructor •() → self::ImplementsBaseClassTypedef
+    : super core::Object::•()
+    ;
+}
+class ImplementsBaseClassTypedef2 extends core::Object implements mai::A {
+  synthetic constructor •() → self::ImplementsBaseClassTypedef2
+    : super core::Object::•()
+    ;
+}
+class ImplementsBaseMixinTypeDef extends core::Object implements mai::M {
+  synthetic constructor •() → self::ImplementsBaseMixinTypeDef
+    : super core::Object::•()
+    ;
+}
+class ImplementsBaseMixinTypeDef2 extends core::Object implements mai::M {
+  synthetic constructor •() → self::ImplementsBaseMixinTypeDef2
+    : super core::Object::•()
+    ;
+}
+class ImplementsBaseClassTypedefOutside extends core::Object implements mai::A {
+  synthetic constructor •() → self::ImplementsBaseClassTypedefOutside
+    : super core::Object::•()
+    ;
+}
+class ImplementsBaseMixinTypeDefOutside extends core::Object implements mai::M {
+  synthetic constructor •() → self::ImplementsBaseMixinTypeDefOutside
+    : super core::Object::•()
+    ;
+}
+
+library /*isNonNullableByDefault*/;
+import self as mai;
+import "dart:core" as core;
+
+typedef ATypeDef = mai::A;
+typedef ATypeDef2 = mai::A;
+typedef MTypeDef = mai::M;
+typedef MTypeDef2 = mai::M;
+base class A extends core::Object {
+  synthetic constructor •() → mai::A
+    : super core::Object::•()
+    ;
+}
+abstract base class M extends core::Object /*isMixinDeclaration*/  {
+}

pkg/front_end/testcases/class_modifiers/base/typedef/main.dart.weak.modular.expect

@@ -0,0 +1,66 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/class_modifiers/base/typedef/main.dart:7:7: Error: The class 'A' can't be implemented outside of its library because it's a base class.
+// class ImplementsBaseClassTypedef implements ATypeDef {}
+//       ^
+//
+// pkg/front_end/testcases/class_modifiers/base/typedef/main.dart:9:7: Error: The class 'A' can't be implemented outside of its library because it's a base class.
+// class ImplementsBaseClassTypedef2 implements ATypeDef2 {}
+//       ^
+//
+// pkg/front_end/testcases/class_modifiers/base/typedef/main.dart:11:7: Error: The mixin 'M' can't be implemented outside of its library because it's a base mixin.
+// class ImplementsBaseMixinTypeDef implements MTypeDef {}
+//       ^
+//
+// pkg/front_end/testcases/class_modifiers/base/typedef/main.dart:13:7: Error: The mixin 'M' can't be implemented outside of its library because it's a base mixin.
+// class ImplementsBaseMixinTypeDef2 implements MTypeDef2 {}
+//       ^
+//
+// pkg/front_end/testcases/class_modifiers/base/typedef/main.dart:19:7: Error: The class 'A' can't be implemented outside of its library because it's a base class.
+// class ImplementsBaseClassTypedefOutside implements AOutsideTypedef {}
+//       ^
+//
+// pkg/front_end/testcases/class_modifiers/base/typedef/main.dart:21:7: Error: The mixin 'M' can't be implemented outside of its library because it's a base mixin.
+// class ImplementsBaseMixinTypeDefOutside implements MOutsideTypedef {}
+//       ^
+//
+import self as self;
+import "main_lib.dart" as mai;
+import "dart:core" as core;
+
+import "org-dartlang-testcase:///main_lib.dart";
+
+typedef AOutsideTypedef = mai::A;
+typedef MOutsideTypedef = mai::M;
+class ImplementsBaseClassTypedef extends core::Object implements mai::A {
+  synthetic constructor •() → self::ImplementsBaseClassTypedef
+    : super core::Object::•()
+    ;
+}
+class ImplementsBaseClassTypedef2 extends core::Object implements mai::A {
+  synthetic constructor •() → self::ImplementsBaseClassTypedef2
+    : super core::Object::•()
+    ;
+}
+class ImplementsBaseMixinTypeDef extends core::Object implements mai::M {
+  synthetic constructor •() → self::ImplementsBaseMixinTypeDef
+    : super core::Object::•()
+    ;
+}
+class ImplementsBaseMixinTypeDef2 extends core::Object implements mai::M {
+  synthetic constructor •() → self::ImplementsBaseMixinTypeDef2
+    : super core::Object::•()
+    ;
+}
+class ImplementsBaseClassTypedefOutside extends core::Object implements mai::A {
+  synthetic constructor •() → self::ImplementsBaseClassTypedefOutside
+    : super core::Object::•()
+    ;
+}
+class ImplementsBaseMixinTypeDefOutside extends core::Object implements mai::M {
+  synthetic constructor •() → self::ImplementsBaseMixinTypeDefOutside
+    : super core::Object::•()
+    ;
+}

pkg/front_end/testcases/class_modifiers/base/typedef/main.dart.weak.outline.expect

@@ -0,0 +1,75 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/class_modifiers/base/typedef/main.dart:7:7: Error: The class 'A' can't be implemented outside of its library because it's a base class.
+// class ImplementsBaseClassTypedef implements ATypeDef {}
+//       ^
+//
+// pkg/front_end/testcases/class_modifiers/base/typedef/main.dart:9:7: Error: The class 'A' can't be implemented outside of its library because it's a base class.
+// class ImplementsBaseClassTypedef2 implements ATypeDef2 {}
+//       ^
+//
+// pkg/front_end/testcases/class_modifiers/base/typedef/main.dart:11:7: Error: The mixin 'M' can't be implemented outside of its library because it's a base mixin.
+// class ImplementsBaseMixinTypeDef implements MTypeDef {}
+//       ^
+//
+// pkg/front_end/testcases/class_modifiers/base/typedef/main.dart:13:7: Error: The mixin 'M' can't be implemented outside of its library because it's a base mixin.
+// class ImplementsBaseMixinTypeDef2 implements MTypeDef2 {}
+//       ^
+//
+// pkg/front_end/testcases/class_modifiers/base/typedef/main.dart:19:7: Error: The class 'A' can't be implemented outside of its library because it's a base class.
+// class ImplementsBaseClassTypedefOutside implements AOutsideTypedef {}
+//       ^
+//
+// pkg/front_end/testcases/class_modifiers/base/typedef/main.dart:21:7: Error: The mixin 'M' can't be implemented outside of its library because it's a base mixin.
+// class ImplementsBaseMixinTypeDefOutside implements MOutsideTypedef {}
+//       ^
+//
+import self as self;
+import "main_lib.dart" as mai;
+import "dart:core" as core;
+
+import "org-dartlang-testcase:///main_lib.dart";
+
+typedef AOutsideTypedef = mai::A;
+typedef MOutsideTypedef = mai::M;
+class ImplementsBaseClassTypedef extends core::Object implements mai::A {
+  synthetic constructor •() → self::ImplementsBaseClassTypedef
+    ;
+}
+class ImplementsBaseClassTypedef2 extends core::Object implements mai::A {
+  synthetic constructor •() → self::ImplementsBaseClassTypedef2
+    ;
+}
+class ImplementsBaseMixinTypeDef extends core::Object implements mai::M {
+  synthetic constructor •() → self::ImplementsBaseMixinTypeDef
+    ;
+}
+class ImplementsBaseMixinTypeDef2 extends core::Object implements mai::M {
+  synthetic constructor •() → self::ImplementsBaseMixinTypeDef2
+    ;
+}
+class ImplementsBaseClassTypedefOutside extends core::Object implements mai::A {
+  synthetic constructor •() → self::ImplementsBaseClassTypedefOutside
+    ;
+}
+class ImplementsBaseMixinTypeDefOutside extends core::Object implements mai::M {
+  synthetic constructor •() → self::ImplementsBaseMixinTypeDefOutside
+    ;
+}
+
+library /*isNonNullableByDefault*/;
+import self as mai;
+import "dart:core" as core;
+
+typedef ATypeDef = mai::A;
+typedef ATypeDef2 = mai::A;
+typedef MTypeDef = mai::M;
+typedef MTypeDef2 = mai::M;
+base class A extends core::Object {
+  synthetic constructor •() → mai::A
+    ;
+}
+abstract base class M extends core::Object /*isMixinDeclaration*/  {
+}

pkg/front_end/testcases/class_modifiers/base/typedef/main.dart.weak.transformed.expect

@@ -0,0 +1,82 @@
+library /*isNonNullableByDefault*/;
+//
+// Problems in library:
+//
+// pkg/front_end/testcases/class_modifiers/base/typedef/main.dart:7:7: Error: The class 'A' can't be implemented outside of its library because it's a base class.
+// class ImplementsBaseClassTypedef implements ATypeDef {}
+//       ^
+//
+// pkg/front_end/testcases/class_modifiers/base/typedef/main.dart:9:7: Error: The class 'A' can't be implemented outside of its library because it's a base class.
+// class ImplementsBaseClassTypedef2 implements ATypeDef2 {}
+//       ^
+//
+// pkg/front_end/testcases/class_modifiers/base/typedef/main.dart:11:7: Error: The mixin 'M' can't be implemented outside of its library because it's a base mixin.
+// class ImplementsBaseMixinTypeDef implements MTypeDef {}
+//       ^
+//
+// pkg/front_end/testcases/class_modifiers/base/typedef/main.dart:13:7: Error: The mixin 'M' can't be implemented outside of its library because it's a base mixin.
+// class ImplementsBaseMixinTypeDef2 implements MTypeDef2 {}
+//       ^
+//
+// pkg/front_end/testcases/class_modifiers/base/typedef/main.dart:19:7: Error: The class 'A' can't be implemented outside of its library because it's a base class.
+// class ImplementsBaseClassTypedefOutside implements AOutsideTypedef {}
+//       ^
+//
+// pkg/front_end/testcases/class_modifiers/base/typedef/main.dart:21:7: Error: The mixin 'M' can't be implemented outside of its library because it's a base mixin.
+// class ImplementsBaseMixinTypeDefOutside implements MOutsideTypedef {}
+//       ^
+//
+import self as self;
+import "main_lib.dart" as mai;
+import "dart:core" as core;
+
+import "org-dartlang-testcase:///main_lib.dart";
+
+typedef AOutsideTypedef = mai::A;
+typedef MOutsideTypedef = mai::M;
+class ImplementsBaseClassTypedef extends core::Object implements mai::A {
+  synthetic constructor •() → self::ImplementsBaseClassTypedef
+    : super core::Object::•()
+    ;
+}
+class ImplementsBaseClassTypedef2 extends core::Object implements mai::A {
+  synthetic constructor •() → self::ImplementsBaseClassTypedef2
+    : super core::Object::•()
+    ;
+}
+class ImplementsBaseMixinTypeDef extends core::Object implements mai::M {
+  synthetic constructor •() → self::ImplementsBaseMixinTypeDef
+    : super core::Object::•()
+    ;
+}
+class ImplementsBaseMixinTypeDef2 extends core::Object implements mai::M {
+  synthetic constructor •() → self::ImplementsBaseMixinTypeDef2
+    : super core::Object::•()
+    ;
+}
+class ImplementsBaseClassTypedefOutside extends core::Object implements mai::A {
+  synthetic constructor •() → self::ImplementsBaseClassTypedefOutside
+    : super core::Object::•()
+    ;
+}
+class ImplementsBaseMixinTypeDefOutside extends core::Object implements mai::M {
+  synthetic constructor •() → self::ImplementsBaseMixinTypeDefOutside
+    : super core::Object::•()
+    ;
+}
+
+library /*isNonNullableByDefault*/;
+import self as mai;
+import "dart:core" as core;
+
+typedef ATypeDef = mai::A;
+typedef ATypeDef2 = mai::A;
+typedef MTypeDef = mai::M;
+typedef MTypeDef2 = mai::M;
+base class A extends core::Object {
+  synthetic constructor •() → mai::A
+    : super core::Object::•()
+    ;
+}
+abstract base class M extends core::Object /*isMixinDeclaration*/  {
+}

pkg/front_end/testcases/class_modifiers/base/typedef/main_lib.dart

@@ -0,0 +1,15 @@
+// Copyright (c) 2023, 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.
+
+base class A {}
+
+typedef ATypeDef = A;
+
+typedef ATypeDef2 = ATypeDef;
+
+base mixin M {}
+
+typedef MTypeDef = M;
+
+typedef MTypeDef2 = MTypeDef;

pkg/front_end/testcases/class_modifiers/base/typedef/test.options

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

tests/language/class_modifiers/base/base_class_implement_error_test.dart

@@ -9,14 +9,14 @@
 import 'base_class_implement_lib.dart';
 
 abstract class AOutside implements BaseClass {}
-// ^
+//             ^
+// [cfe] The class 'BaseClass' can't be implemented outside of its library because it's a base class.
 // [analyzer] unspecified
-// [cfe] unspecified
 
 class BOutside implements BaseClass {
-// ^
+//    ^
+// [cfe] The class 'BaseClass' can't be implemented outside of its library because it's a base class.
 // [analyzer] unspecified
-// [cfe] unspecified
   @override
   int foo = 1;
 }

tests/language/class_modifiers/base/base_class_typedef_implement_error_test.dart

@@ -9,9 +9,20 @@
 import 'base_class_typedef_lib.dart';
 
 class BTypeDef implements BaseClassTypeDef {
-// ^
+//    ^
+// [cfe] The class 'BaseClass' can't be implemented outside of its library because it's a base class.
+// [analyzer] unspecified
+  @override
+  int foo = 1;
+}
+
+// Testing another layer of typedefs outside of the library.
+typedef BaseClassTypeDef2 = BaseClassTypeDef;
+
+class BTypeDef2 implements BaseClassTypeDef2 {
+//    ^
+// [cfe] The class 'BaseClass' can't be implemented outside of its library because it's a base class.
 // [analyzer] unspecified
-// [cfe] unspecified
   @override
   int foo = 1;
 }

tests/language/class_modifiers/base/base_class_typedef_used_outside_error_test.dart

@@ -13,8 +13,8 @@ import 'base_class_typedef_used_outside_lib.dart';
 typedef ATypeDef = BaseClass;
 
 class B implements ATypeDef {
-// ^
+//    ^
+// [cfe] The class 'BaseClass' can't be implemented outside of its library because it's a base class.
 // [analyzer] unspecified
-// [cfe] unspecified
   int foo = 1;
 }

tests/language/class_modifiers/base/base_mixin_implement_error_test.dart

@@ -9,14 +9,14 @@
 import 'base_mixin_implement_lib.dart';
 
 abstract class AOutside implements BaseMixin {}
-// ^
+//             ^
+// [cfe] The mixin 'BaseMixin' can't be implemented outside of its library because it's a base mixin.
 // [analyzer] unspecified
-// [cfe] unspecified
 
 class BOutside implements BaseMixin {
-// ^
+//    ^
+// [cfe] The mixin 'BaseMixin' can't be implemented outside of its library because it's a base mixin.
 // [analyzer] unspecified
-// [cfe] unspecified
   @override
   int foo = 1;
 }