CNLT with descriptors but no valid enum fields has to clear the EnumCache.

src/objects.h

 // 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 2491 matching lines @@
     FixedArray* bridge = FixedArray::cast(get(kEnumCacheIndex));
     return bridge->get(kEnumCacheBridgeCacheIndex);
   }
 
   Object** GetEnumCacheSlot() {
     ASSERT(HasEnumCache());
     return HeapObject::RawField(reinterpret_cast<HeapObject*>(this),
                                 kEnumCacheOffset);
   }
 
+  void ClearEnumCache();
+
   // Initialize or change the enum cache,
   // using the supplied storage for the small "bridge".
   void SetEnumCache(FixedArray* bridge_storage,
                     FixedArray* new_cache,
                     Object* new_index_cache);
 
   // Accessors for fetching instance descriptor at descriptor number.
   inline String* GetKey(int descriptor_number);
   inline Object** GetKeySlot(int descriptor_number);
   inline Object* GetValue(int descriptor_number);
@@ skipping 6452 matching lines @@
     } else {
       value &= ~(1 << bit_position);
     }
     return value;
   }
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_OBJECTS_H_