Fix for issue 4070

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

 // Copyright (c) 2014, 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.
 
 // This code was auto-generated, is not intended to be edited, and is subject to
 // significant change. Please see the README file for more information.
 
 library engine.parser;
 
 import "dart:math" as math;
@@ skipping 6543 matching lines @@
           if (!_tokenMatchesString(keyword, ASYNC)) {
             _reportErrorForToken(ParserErrorCode.INVALID_SYNC, keyword);
             keyword = null;
           } else if (star != null) {
             _reportErrorForToken(
                 ParserErrorCode.INVALID_STAR_AFTER_ASYNC,
                 star);
           }
         }
         Token functionDefinition = andAdvance;
+        if (_matchesKeyword(Keyword.RETURN)) {
+          _reportErrorForToken(
+              ParserErrorCode.UNEXPECTED_TOKEN,
+              andAdvance);
+        }
         Expression expression = parseExpression2();
         Token semicolon = null;
         if (!inExpression) {
           semicolon = _expect(TokenType.SEMICOLON);
         }
         if (!_parseFunctionBodies) {
           return new EmptyFunctionBody(
               _createSyntheticToken(TokenType.SEMICOLON));
         }
         return new ExpressionFunctionBody(
@@ skipping 5548 matching lines @@
    * Copy resolution data from one node to another.
    *
    * @param fromNode the node from which resolution information will be copied
    * @param toNode the node to which resolution information will be copied
    */
   static void copyResolutionData(AstNode fromNode, AstNode toNode) {
     ResolutionCopier copier = new ResolutionCopier();
     copier._isEqualNodes(fromNode, toNode);
   }
 }