Report a compile-time error if async/sync/yield used as an identifier.

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 3656 matching lines @@
    *
    * <pre>
    * identifier ::=
    *     IDENTIFIER
    * </pre>
    *
    * @return the simple identifier that was parsed
    */
   SimpleIdentifier parseSimpleIdentifier() {
     if (_matchesIdentifier()) {
+      String lexeme = _currentToken.lexeme;
+      if ((_inAsync || _inGenerator) &&
+          (lexeme == 'async' || lexeme == 'await' || lexeme == 'yield')) {
+        _reportErrorForCurrentToken(
+            ParserErrorCode.ASYNC_KEYWORD_USED_AS_IDENTIFIER);
+      }
       return new SimpleIdentifier(getAndAdvance());
     }
     _reportErrorForCurrentToken(ParserErrorCode.MISSING_IDENTIFIER);
     return _createSyntheticIdentifier();
   }
 
   /**
    * Parse a statement, starting with the given token.
    *
    * @param token the first token of the statement
@@ skipping 6335 matching lines @@
   static const ParserErrorCode ASSERT_DOES_NOT_TAKE_THROW =
       const ParserErrorCode(
           'ASSERT_DOES_NOT_TAKE_THROW',
           "Assert cannot be called on throws");
 
   static const ParserErrorCode ASSERT_DOES_NOT_TAKE_RETHROW =
       const ParserErrorCode(
           'ASSERT_DOES_NOT_TAKE_RETHROW',
           "Assert cannot be called on rethrows");
 
+  /**
+   * 16.32 Identifier Reference: It is a compile-time error if any of the
+   * identifiers async, await, or yield is used as an identifier in a function
+   * body marked with either async, async*, or sync*.
+   */
+  static const ParserErrorCode ASYNC_KEYWORD_USED_AS_IDENTIFIER =
+      const ParserErrorCode(
+          'ASYNC_KEYWORD_USED_AS_IDENTIFIER',
+          "The keywords 'async', 'await', and 'yield' may not be used as identifiers in an asynchronous or generator function.");
+
   static const ParserErrorCode BREAK_OUTSIDE_OF_LOOP = const ParserErrorCode(
       'BREAK_OUTSIDE_OF_LOOP',
       "A break statement cannot be used outside of a loop or switch statement");
 
   static const ParserErrorCode CLASS_IN_CLASS = const ParserErrorCode(
       'CLASS_IN_CLASS',
       "Classes cannot be declared inside other classes");
 
   static const ParserErrorCode COLON_IN_PLACE_OF_IN = const ParserErrorCode(
       'COLON_IN_PLACE_OF_IN',
@@ skipping 2061 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);
   }
 }