improve parser recovery for import statements

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 5951 matching lines @@
     SimpleIdentifier prefix = null;
     if (_matchesKeyword(Keyword.DEFERRED)) {
       deferredToken = getAndAdvance();
     }
     if (_matchesKeyword(Keyword.AS)) {
       asToken = getAndAdvance();
       prefix = parseSimpleIdentifier();
     } else if (deferredToken != null) {
       _reportErrorForCurrentToken(
           ParserErrorCode.MISSING_PREFIX_IN_DEFERRED_IMPORT);
-    } else if (!_matches(TokenType.SEMICOLON) &&
-        _tokenMatchesKeyword(_peek(), Keyword.AS)) {
-      _reportErrorForCurrentToken(
-          ParserErrorCode.UNEXPECTED_TOKEN, [_currentToken]);
-      _advance();
-      asToken = getAndAdvance();
-      prefix = parseSimpleIdentifier();
+    } else if (!_matches(TokenType.SEMICOLON)) {
+      Token nextToken = _peek();
+      if (_tokenMatchesKeyword(nextToken, Keyword.AS) ||
+          _tokenMatchesString(nextToken, _SHOW) ||
+          _tokenMatchesString(nextToken, _HIDE)) {
+        _reportErrorForCurrentToken(
+            ParserErrorCode.UNEXPECTED_TOKEN, [_currentToken]);
+        _advance();
+        if (_matchesKeyword(Keyword.AS)) {
+          asToken = getAndAdvance();
+          prefix = parseSimpleIdentifier();
+        }
+      }
     }
     List<Combinator> combinators = _parseCombinators();
     Token semicolon = _expectSemicolon();
     return new ImportDirective(commentAndMetadata.comment,
         commentAndMetadata.metadata, importKeyword, libraryUri, deferredToken,
         asToken, prefix, combinators, semicolon);
   }
 
   /**
    * Parse a list of initialized identifiers. The [commentAndMetadata] is the
@@ skipping 4581 matching lines @@
   }
 
   /**
    * Copy resolution data from the [fromNode] to the [toNode].
    */
   static void copyResolutionData(AstNode fromNode, AstNode toNode) {
     ResolutionCopier copier = new ResolutionCopier();
     copier._isEqualNodes(fromNode, toNode);
   }
 }