Do not fail when an enum constant is annotated (issue 26413)

pkg/analyzer/test/src/dart/constant/utilities_test.dart

 // Copyright (c) 2016, 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.
 
 library analyzer.test.src.dart.constant.utilities_test;
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/src/dart/ast/token.dart';
@@ skipping 43 matching lines @@
         ElementFactory.compilationUnit('/test.dart', _source)..source = _source;
     ElementFactory.library(_context, 'L').definingCompilationUnit =
         compilationUnitElement;
     ElementAnnotationImpl elementAnnotation =
         new ElementAnnotationImpl(compilationUnitElement);
     _node = elementAnnotation.annotationAst = AstFactory.annotation(
         AstFactory.identifier3('x'))..elementAnnotation = elementAnnotation;
     expect(_findAnnotations(), contains(_node));
   }
 
+  void test_visitAnnotation_enumConstant() {
+    // Analyzer ignores annotations on enum constant declarations.
+    Annotation annotation = AstFactory.annotation2(
+        AstFactory.identifier3('A'), null, AstFactory.argumentList());
+    _node = new EnumConstantDeclaration(
+        null, <Annotation>[annotation], AstFactory.identifier3('C'));
+    expect(_findConstants(), isEmpty);
+  }
+
   /**
    * Test an annotation that represents the invocation of a constant
    * constructor.
    */
   void test_visitAnnotation_invocation() {
     CompilationUnitElement compilationUnitElement =
         ElementFactory.compilationUnit('/test.dart', _source)..source = _source;
     ElementFactory.library(_context, 'L').definingCompilationUnit =
         compilationUnitElement;
     ElementAnnotationImpl elementAnnotation =
@@ skipping 271 matching lines @@
 
   void _visitNode(AstNode node) {
     node.accept(_createReferenceFinder(_head));
   }
 }
 
 class _TestAnalysisContext extends TestAnalysisContext {
   @override
   InternalAnalysisContext getContextFor(Source source) => this;
 }