Make accessors for oddball objects return Oddball* instead of Object*.

src/objects.cc

 // Copyright 2011 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 527 matching lines @@
   Heap* heap = name->GetHeap();
 
   // Traverse the prototype chain from the current object (this) to
   // the holder and check for access rights. This avoids traversing the
   // objects more than once in case of interceptors, because the
   // holder will always be the interceptor holder and the search may
   // only continue with a current object just after the interceptor
   // holder in the prototype chain.
   // Proxy handlers do not use the proxy's prototype, so we can skip this.
   if (!result->IsHandler()) {
-    Object* last = result->IsProperty() ? result->holder() : heap->null_value();
+    Object* last = result->IsProperty()
+        ? result->holder()
+        : Object::cast(heap->null_value());
     ASSERT(this != this->GetPrototype());
     for (Object* current = this; true; current = current->GetPrototype()) {
       if (current->IsAccessCheckNeeded()) {
         // Check if we're allowed to read from the current object. Note
         // that even though we may not actually end up loading the named
         // property from the current object, we still check that we have
         // access to it.
         JSObject* checked = JSObject::cast(current);
         if (!heap->isolate()->MayNamedAccess(checked, name, v8::ACCESS_GET)) {
           return checked->GetPropertyWithFailedAccessCheck(receiver,
@@ skipping 11605 matching lines @@
   if (break_point_objects()->IsUndefined()) return 0;
   // Single break point.
   if (!break_point_objects()->IsFixedArray()) return 1;
   // Multiple break points.
   return FixedArray::cast(break_point_objects())->length();
 }
 #endif
 
 
 } }  // namespace v8::internal