anchor.diff:              .relevance));
     }
   
  +  /// See: https://github.com/dart-lang/sdk/issues/35529
  +  Future<void> test_project_suggestMixins() async {
  +    await addProjectFile('lib/a.dart', r'''
  +mixin M { }
  +class A { }
  +''');
  +
  +    await addTestFile('''
  +class C extends Object with ^
  +''');
  +
  +    assertSuggestion(
  +        completion: 'M',
  +        element: ElementKind.MIXIN,
  +        kind: CompletionSuggestionKind.INVOCATION);
  +    assertSuggestion(
  +        completion: 'A',
  +        element: ElementKind.CLASS,
  +        kind: CompletionSuggestionKind.INVOCATION);
  +  }
  +
     Future<void> test_sdk_lib_future_isNotDuplicated() async {
       await addTestFile('''
   void main() {
  
positive.code:         kind: CompletionSuggestionKind.INVOCATION);
    }
  
    /// see: https://github.com/dart-lang/sdk/issues/40620
    Future<void> test_project_filterImports_namedConstructors() async {
      await addProjectFile('lib/a.dart', r'''
  class A {
  
negative.code:         kind: CompletionSuggestionKind.INVOCATION);
    }
  
    /// See: https://github.com/dart-lang/sdk/issues/40620
    Future<void> test_project_filterImports_enumValues() async {
      await addProjectFile('lib/a.dart', r'''
  enum E {
  