@Override
 public void setAncestor(NodeDescriptor oldDescriptor) {
   super.setAncestor(oldDescriptor);
   final Boolean isPrimitive = ((FieldDescriptorImpl) oldDescriptor).myIsPrimitive;
   if (isPrimitive != null) { // was cached
     // do not loose cached info
     myIsPrimitive = isPrimitive;
   }
 }