Diagnose unterminated "grouping" characters.

dart/frog/leg/tools/mini_parser.dart

 // Copyright (c) 2012, 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('parser');
 
 #import('dart:io');
 
 #import('../../../utils/utf8/utf8.dart');
 
@@ skipping 82 matching lines @@
   try {
     Token token = scan(file);
     if (!options.scanOnly) parser.parseUnit(token);
   } catch (ParserError ex) {
     if (options.throwOnError) {
       throw;
     } else {
       print(ex);
     }
   } catch (MalformedInputException ex) {
-    print('$filename: $ex');
+    // Already diagnosed.
   } catch (var ex) {
     print('Error in file: $filename');
     throw;
   }
   if (options.buildAst) {
     MyNodeListener l = listener;
     if (!l.nodes.isEmpty()) {
       String message = 'Stack not empty after parsing';
       print(formatError(message, l.nodes.head.getBeginToken(),
                         l.nodes.head.getEndToken(), file));
       throw message;
     }
   }
 }
 
 Token scan(MySourceFile source) {
   Scanner scanner = new ByteArrayScanner(source.rawText);
   try {
     return scanner.tokenize();
   } catch (MalformedInputException ex) {
-    var message = ex.message;
-    if (message is !String) message = "unexpected character";
-    Token fakeToken = new Token(QUESTION_INFO, scanner.charOffset);
-    print(formatError(message, fakeToken, fakeToken, source));
+    if (ex.position is Token) {
+      print(formatError(ex.message, ex.position, ex.position, source));
+    } else {
+      Token fakeToken = new Token(QUESTION_INFO, ex.position);
+      print(formatError(ex.message, fakeToken, fakeToken, source));
+    }
     throw;
   }
 }
 
 var filesWithCrashes;
 
 void parseFilesFrom(InputStream input, MyOptions options, Function whenDone) {
   void readLine(String line) {
     stopwatch.start();
     try {
@@ skipping 181 matching lines @@
 String _GREEN_COLOR = '\u001b[32m';
 String _RED_COLOR = '\u001b[31m';
 String _MAGENTA_COLOR = '\u001b[35m';
 String _NO_COLOR = '\u001b[0m';
 
 class Mock {
   const Mock();
   bool get useColors() => true;
   internalError(message) { throw message.toString(); }
 }