Make sure that we do not call is_extensible on the global proxy....

src/runtime.cc

Index: src/runtime.cc
===================================================================
--- src/runtime.cc	(revision 6673)
+++ src/runtime.cc	(working copy)
@@ -887,6 +887,12 @@
 static MaybeObject* Runtime_IsExtensible(Arguments args) {
   ASSERT(args.length() == 1);
   CONVERT_CHECKED(JSObject, obj, args[0]);
+  if (obj->IsJSGlobalProxy()) {
+    Object* proto = obj->GetPrototype();
+    if (proto->IsNull()) return obj;

[Mads Ager (chromium), 2011/02/08 13:04:22]

Return false? Otherwise this will be interpreted as true.

[Rico, 2011/02/08 13:08:58]

Done.

+    ASSERT(proto->IsJSGlobalObject());
+    obj = JSObject::cast(proto);
+  }
   return obj->map()->is_extensible() ?  Heap::true_value()

[Mads Ager (chromium), 2011/02/08 13:04:22]

Remove extra space.

[Rico, 2011/02/08 13:08:58]

Done.

                                      : Heap::false_value();
 }