In reply to dave_59:
In reply to peter:
You cannot cast a base class variable to an extended class variable when the base class variable does not contain a type compatible object. extend.b would not exist. Please review the link I gave you in your previous question.
Thanks for reply.
if base_handle is a reference to derived class, and i use the $cast(extend_handle,base_handle), it is permitted. if base_handle is not a reference to derived class , it is not permitted using $cast(extend_handle,base_handle).
is it correct?