Fix js_test in dart2js checked mode

sdk/lib/js/dart2js/js_dart2js.dart

 // Copyright (c) 2013, 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.
 
 /**
  * Support for interoperating with JavaScript.
  * 
  * This library provides access to JavaScript objects from Dart, allowing
  * Dart code to get and set properties, and call methods of JavaScript objects
  * and invoke JavaScript functions. The library takes care of converting
@@ skipping 358 matching lines @@
     if (start < 0 || start > this.length) {
       throw new RangeError.range(start, 0, this.length);
     }
     if (end < start || end > this.length) {
       throw new RangeError.range(end, start, this.length);
     }
   }
 
   // Methods required by ListMixin
 
-  E operator [](int index) {
-    _checkIndex(index);
+  E operator [](index) {
+    if (index is num && index == index.toInt()) {

[Jacob, 2013/10/29 22:08:03]

can you file a bug to find a better long term solution?

[justinfagnani, 2013/10/30 02:16:36]

Done.

+      _checkIndex(index);
+    }
     return super[index];
   }
 
-  void operator []=(int index, E value) {
-    _checkIndex(index);
+  void operator []=(index, E value) {
+    if (index is num && index == index.toInt()) {
+      _checkIndex(index);
+    }
     super[index] = value;
   }
 
   int get length => super['length'];
 
   void set length(int length) { super['length'] = length; }
 
 
   // Methods overriden for better performance
 
@@ skipping 104 matching lines @@
       JS('bool', 'typeof # == "string"', o) ||
       JS('bool', 'typeof # == "number"', o) ||
       JS('bool', 'typeof # == "boolean"', o)) {
     return o;
   } else if (o is Blob || o is KeyRange || o is ImageData || o is Node
       || o is TypedData) {
     return JS('Blob|KeyRange|ImageData|Node|TypedData', '#', o);
   } else if (JS('bool', '# instanceof Date', o)) {
     var ms = JS('num', '#.getMilliseconds()', o);
     return new DateTime.fromMillisecondsSinceEpoch(ms);
+  } else if (JS('bool', '#.constructor === DartObject', o)) {
+    return JS('', '#.o', o);
   } else {
     return _wrapToDart(o);
   }
 }
 
 JsObject _wrapToDart(o) {
   if (JS('bool', 'typeof # == "function"', o)) {
     return _getDartProxy(o, _DART_CLOSURE_PROPERTY_NAME,
         (o) => new JsFunction._fromJs(o));
   } else if (JS('bool', '# instanceof Array', o)) {
     return _getDartProxy(o, _DART_OBJECT_PROPERTY_NAME,
         (o) => new JsArray._fromJs(o));
-  } else if (JS('bool', '#.constructor === DartObject', o)) {
-    return JS('', '#.o', o);
   } else {
     return _getDartProxy(o, _DART_OBJECT_PROPERTY_NAME,
         (o) => new JsObject._fromJs(o));
   }
 }
 
 Object _getDartProxy(o, String propertyName, createProxy(o)) {
   var dartProxy = JS('', '#[#]', o, propertyName);
   if (dartProxy == null) {
     dartProxy = createProxy(o);
     _defineProperty(o, propertyName, dartProxy);
   }
   return dartProxy;
 }