Reject deprecated language features.

dart/sdk/lib/_internal/compiler/implementation/lib/js_helper.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('dart:_js_helper');
+library _js_helper;
 
-#import('dart:collection');
+import 'dart:collection';
 
-#source('constant_map.dart');
-#source('native_helper.dart');
-#source('regexp_helper.dart');
-#source('string_helper.dart');
-#source('mirror_opt_in_message.dart');
+part 'constant_map.dart';
+part 'native_helper.dart';
+part 'regexp_helper.dart';
+part 'string_helper.dart';
+part 'mirror_opt_in_message.dart';
 
 // Performance critical helper methods.
 add(var a, var b) => (a is num && b is num)
     ? JS('num', r'# + #', a, b)
     : add$slow(a, b);
 
 sub(var a, var b) => (a is num && b is num)
     ? JS('num', r'# - #', a, b)
     : sub$slow(a, b);
 
@@ skipping 1469 matching lines @@
     result = new TypeImpl(key);
     JS('var', r'#[#] = #', runtimeTypeCache, key, result);
   }
   return result;
 }
 
 String getRuntimeTypeString(var object) {
   var typeInfo = JS('var', r'#.builtin$typeInfo', object);
   return JS('String', r'#.runtimeType', typeInfo);
 }