Fix detection of indexed properties in Object.defineProperty()

src/v8natives.js

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 932 matching lines @@
       if (updated || reconfigured) {
         NotifyChange(reconfigured ? "reconfigured" : "updated",
             obj, "length", length_desc.value_);
       }
     }
     return true;
   }
 
   // Step 4 - Special handling for array index.
   var index = ToUint32(p);
-  if (index == ToNumber(p) && index != 4294967295) {
+  if (ToString(index) == p && index != 4294967295) {
     var length = obj.length;
     var length_desc = GetOwnProperty(obj, "length");
     if ((index >= length && !length_desc.isWritable()) ||
         !DefineObjectProperty(obj, p, desc, true)) {
       if (should_throw) {
         throw MakeTypeError("define_disallowed", [p]);
       } else {
         return false;
       }
     }
@@ skipping 826 matching lines @@
 
 function SetUpFunction() {
   %CheckIsBootstrapping();
   InstallFunctions($Function.prototype, DONT_ENUM, $Array(
     "bind", FunctionBind,
     "toString", FunctionToString
   ));
 }
 
 SetUpFunction();