| Index: src/v8natives.js
 | 
| ===================================================================
 | 
| --- src/v8natives.js	(revision 4711)
 | 
| +++ src/v8natives.js	(working copy)
 | 
| @@ -604,7 +604,13 @@
 | 
|      flag |= DONT_DELETE;
 | 
|  
 | 
|    if (IsDataDescriptor(desc) || IsGenericDescriptor(desc)) {
 | 
| -    flag |= desc.isWritable() ? 0 : READ_ONLY;
 | 
| +    if (desc.hasWritable()) {
 | 
| +      flag |= desc.isWritable() ? 0 : READ_ONLY;
 | 
| +    } else if (!IS_UNDEFINED(current)) {
 | 
| +      flag |= current.isWritable() ? 0 : READ_ONLY;
 | 
| +    } else {
 | 
| +      flag |= READ_ONLY;
 | 
| +    }
 | 
|      %DefineOrRedefineDataProperty(obj, p, desc.getValue(), flag);
 | 
|    } else {
 | 
|      if (desc.hasGetter() && IS_FUNCTION(desc.getGet())) {
 | 
| 
 |