Report MIXINS_SUPER_CLASS.

Bug: #42256
Change-Id: I49c70d5a172062fed4d8663d95701ba855effda6
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/153823
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Commit-Queue: Konstantin Shcheglov <scheglov@google.com>

Author: scheglov

pkg/analyzer/lib/error/error.dart

@@ -240,6 +240,7 @@ const List<ErrorCode> errorCodeValues = [
   CompileTimeErrorCode.MIXIN_SUPER_CLASS_CONSTRAINT_DISALLOWED_CLASS,
   CompileTimeErrorCode.MIXIN_SUPER_CLASS_CONSTRAINT_NON_INTERFACE,
   CompileTimeErrorCode.MIXIN_WITH_NON_CLASS_SUPERCLASS,
+  CompileTimeErrorCode.MIXINS_SUPER_CLASS,
   CompileTimeErrorCode.MULTIPLE_REDIRECTING_CONSTRUCTOR_INVOCATIONS,
   CompileTimeErrorCode.MULTIPLE_SUPER_INITIALIZERS,
   CompileTimeErrorCode.NO_ANNOTATION_CONSTRUCTOR_ARGUMENTS,

pkg/analyzer/lib/src/error/codes.dart

@@ -4262,6 +4262,18 @@ class CompileTimeErrorCode extends AnalyzerErrorCode {
       CompileTimeErrorCode('MIXIN_WITH_NON_CLASS_SUPERCLASS',
           "Mixin can only be applied to class.");
 
+  /**
+   * Technically this is [IMPLEMENTS_SUPER_CLASS].
+   * See https://github.com/dart-lang/sdk/issues/25765#issuecomment-307422593
+   *
+   * Parameters:
+   * 0: the name of the class that appears in both "extends" and "with" clauses
+   */
+  static const CompileTimeErrorCode MIXINS_SUPER_CLASS = CompileTimeErrorCode(
+      'MIXINS_SUPER_CLASS',
+      "'{0}' can't be used in both 'extends' and 'with' clauses.",
+      correction: "Try removing one of the occurrences.");
+
   /**
    * 7.6.1 Generative Constructors: A generative constructor may be redirecting,
    * in which case its only action is to invoke another generative constructor.

pkg/analyzer/lib/src/generated/error_verifier.dart

@@ -1248,6 +1248,7 @@ class ErrorVerifier extends RecursiveAstVisitor<void> {
       _checkForRepeatedType(implementsClause?.interfaces,
           CompileTimeErrorCode.IMPLEMENTS_REPEATED);
       _checkImplementsSuperClass(implementsClause);
+      _checkMixinsSuperClass(withClause);
       _checkMixinInference(node, withClause);
       _checkForMixinWithConflictingPrivateMember(withClause, superclass);
       _checkForConflictingGenerics(node);
@@ -4626,27 +4627,27 @@ class ErrorVerifier extends RecursiveAstVisitor<void> {
     }
   }
 
-  /// Verify that the given class [declaration] does not have the same class in
-  /// the 'extends' and 'implements' clauses.
+  /// Verify that the current class does not have the same class in the
+  /// 'extends' and 'implements' clauses.
   ///
   /// See [CompileTimeErrorCode.IMPLEMENTS_SUPER_CLASS].
   void _checkImplementsSuperClass(ImplementsClause implementsClause) {
-    // prepare super type
-    InterfaceType superType = _enclosingClass.supertype;
-    if (superType == null) {
+    if (implementsClause == null) {
       return;
     }
-    // prepare interfaces
-    if (implementsClause == null) {
+
+    var superElement = _enclosingClass.supertype?.element;
+    if (superElement == null) {
       return;
     }
-    // check interfaces
-    for (TypeName interfaceNode in implementsClause.interfaces) {
-      if (interfaceNode.type == superType) {
+
+    for (var interfaceNode in implementsClause.interfaces) {
+      if (interfaceNode.type.element == superElement) {
         _errorReporter.reportErrorForNode(
-            CompileTimeErrorCode.IMPLEMENTS_SUPER_CLASS,
-            interfaceNode,
-            [superType]);
+          CompileTimeErrorCode.IMPLEMENTS_SUPER_CLASS,
+          interfaceNode,
+          [superElement],
+        );
       }
     }
   }
@@ -4720,6 +4721,31 @@ class ErrorVerifier extends RecursiveAstVisitor<void> {
     }
   }
 
+  /// Verify that the current class does not have the same class in the
+  /// 'extends' and 'with' clauses.
+  ///
+  /// See [CompileTimeErrorCode.IMPLEMENTS_SUPER_CLASS].
+  void _checkMixinsSuperClass(WithClause withClause) {
+    if (withClause == null) {
+      return;
+    }
+
+    var superElement = _enclosingClass.supertype?.element;
+    if (superElement == null) {
+      return;
+    }
+
+    for (var mixinNode in withClause.mixinTypes) {
+      if (mixinNode.type.element == superElement) {
+        _errorReporter.reportErrorForNode(
+          CompileTimeErrorCode.MIXINS_SUPER_CLASS,
+          mixinNode,
+          [superElement],
+        );
+      }
+    }
+  }
+
   void _checkUseOfCovariantInParameters(FormalParameterList node) {
     AstNode parent = node.parent;
     if (_enclosingClass != null &&

pkg/analyzer/test/src/diagnostics/mixins_super_class_test.dart

@@ -0,0 +1,35 @@
+// Copyright (c) 2020, the Dart project authors. Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'package:analyzer/src/error/codes.dart';
+import 'package:test_reflective_loader/test_reflective_loader.dart';
+
+import '../dart/resolution/driver_resolution.dart';
+
+main() {
+  defineReflectiveSuite(() {
+    defineReflectiveTests(MixinsSuperClassTest);
+  });
+}
+
+@reflectiveTest
+class MixinsSuperClassTest extends DriverResolutionTest {
+  test_class() async {
+    await assertErrorsInCode(r'''
+class A {}
+class B extends A with A {}
+''', [
+      error(CompileTimeErrorCode.MIXINS_SUPER_CLASS, 34, 1),
+    ]);
+  }
+
+  test_classAlias() async {
+    await assertErrorsInCode(r'''
+class A {}
+class B = A with A;
+''', [
+      error(CompileTimeErrorCode.MIXINS_SUPER_CLASS, 28, 1),
+    ]);
+  }
+}

pkg/analyzer/test/src/diagnostics/private_collision_in_mixin_application_test.dart

@@ -147,22 +147,6 @@ class C extends A with B {}
     ]);
   }
 
-  test_class_superclassAndMixin_same() async {
-    newFile('/test/lib/a.dart', content: r'''
-class A {
-  void _foo() {}
-}
-''');
-
-    await assertErrorsInCode('''
-import 'a.dart';
-
-class C extends A with A {}
-''', [
-      error(CompileTimeErrorCode.PRIVATE_COLLISION_IN_MIXIN_APPLICATION, 41, 1),
-    ]);
-  }
-
   test_class_superclassAndMixin_sameLibrary() async {
     await assertErrorsInCode('''
 class A {
@@ -256,26 +240,6 @@ class B {
 import 'a.dart';
 
 class C = A with B;
-''', [
-      error(CompileTimeErrorCode.PRIVATE_COLLISION_IN_MIXIN_APPLICATION, 35, 1),
-    ]);
-  }
-
-  test_classTypeAlias_superclassAndMixin_same() async {
-    newFile('/test/lib/a.dart', content: r'''
-class A {
-  void _foo() {}
-}
-
-class B {
-  void _foo() {}
-}
-''');
-
-    await assertErrorsInCode('''
-import 'a.dart';
-
-class C = A with A;
 ''', [
       error(CompileTimeErrorCode.PRIVATE_COLLISION_IN_MIXIN_APPLICATION, 35, 1),
     ]);

pkg/analyzer/test/src/diagnostics/test_all.dart

@@ -310,6 +310,7 @@ import 'mixin_super_class_constraint_non_interface_test.dart'
     as mixin_super_class_constraint_non_interface;
 import 'mixin_with_non_class_superclass_test.dart'
     as mixin_with_non_class_superclass;
+import 'mixins_super_class_test.dart' as mixins_super_class;
 import 'must_be_a_native_function_type_test.dart'
     as must_be_a_native_function_type;
 import 'must_be_a_subtype_test.dart' as must_be_a_subtype;
@@ -744,6 +745,7 @@ main() {
     mixin_on_sealed_class.main();
     mixin_super_class_constraint_non_interface.main();
     mixin_with_non_class_superclass.main();
+    mixins_super_class.main();
     must_be_a_native_function_type.main();
     must_be_a_subtype.main();
     must_be_immutable.main();