Reject non-ASCII identifiers.

dart/lib/compiler/implementation/scanner/scanner_task.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.
 
 class ScannerTask extends CompilerTask {
   ScannerTask(Compiler compiler) : super(compiler);
   String get name => 'Scanner';
 
   void scanLibrary(LibraryElement library) {
     var compilationUnit = library.entryCompilationUnit;
@@ skipping 94 matching lines @@
     LibraryElement importedLibrary = loadLibrary(resolved, argument, resolved);
     importLibrary(compilationUnit.getLibrary(),
                   importedLibrary,
                   tag,
                   compilationUnit);
     return resolved;
   }
 
   void scanElements(CompilationUnitElement compilationUnit) {
     Script script = compilationUnit.script;
-    Token tokens;
-    try {
-      tokens = new StringScanner(script.text).tokenize();
-    } on MalformedInputException catch (ex) {
-      Token token;
-      var message;
-      if (ex.position is num) {
-        // TODO(ahe): Always use tokens in MalformedInputException.
-        token = new Token(EOF_INFO, ex.position);
-      } else {
-        token = ex.position;
-      }
-      compiler.cancel(ex.message, token: token);
-    }
+    Token tokens = new StringScanner(script.text).tokenize();
     compiler.dietParser.dietParse(compilationUnit, tokens);
   }
 
   LibraryElement loadLibrary(Uri uri, Node node, Uri canonicalUri) {
     bool newLibrary = false;
     LibraryElement library =
       compiler.libraries.putIfAbsent(uri.toString(), () {
           newLibrary = true;
           Script script = compiler.readScript(uri, node);
           LibraryElement element = new LibraryElement(script, canonicalUri);
@@ skipping 87 matching lines @@
   static const int RESOURCE = 4;
 
   /** Next state. */
   static const List<int> NEXT =
       const <int>[NO_TAG_SEEN,
                   IMPORT, // Only one library tag is allowed.
                   IMPORT,
                   SOURCE,
                   RESOURCE];
 }