Skeleton for lexical error recovery.

pkg/dart_scanner/lib/src/array_based_scanner.dart

 // Copyright (c) 2011, 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 dart_scanner.array_based_scanner;
 
 import 'keyword.dart' show
     Keyword;
 
 import 'precedence.dart' show
@@ skipping 17 matching lines @@
     $LF,
     $STX;
 
 import 'abstract_scanner.dart' show
     AbstractScanner;
 
 import 'package:compiler_util/link.dart' show
     Link;
 
 abstract class ArrayBasedScanner extends AbstractScanner {
+  bool hasErrors = false;
+
   ArrayBasedScanner(bool includeComments)
       : super(includeComments);
 
   /**
    * The stack of open groups, e.g [: { ... ( .. :]
    * Each BeginGroupToken has a pointer to the token where the group
    * ends. This field is set when scanning the end group token.
    */
   Link<BeginGroupToken> groupingStack = const Link<BeginGroupToken>();
 
@@ skipping 169 matching lines @@
       groupingStack = groupingStack.tail;
     }
   }
 
   void appendComment(start, bool asciiOnly) {
     if (!includeComments) return;
     appendSubstringToken(COMMENT_INFO, start, asciiOnly);
   }
 
   void appendErrorToken(ErrorToken token) {
+    hasErrors = true;
     tail.next = token;
     tail = token;
   }
 
   /**
    * This method is called to discard '<' from the "grouping" stack.
    *
    * [PartialParser.skipExpression] relies on the fact that we do not
    * create groups for stuff like:
    * [:a = b < c, d = e > f:].
    *
    * In other words, this method is called when the scanner recognizes
    * something which cannot possibly be part of a type parameter/argument
    * list, like the '=' in the above example.
    */
   void discardOpenLt() {
     while (!groupingStack.isEmpty &&
         identical(groupingStack.head.kind, LT_TOKEN)) {
       groupingStack = groupingStack.tail;
     }
   }
 }