In reply to dave_59:
Thank you dave.
I already know that the source handle should be an extension of the destination class type.
But, In my second $cast, pc is upcast of cc but pc is the parent class handle of cc2 class.
So, i think pc is still not the extension of the cc class.
Isn’t it right?
Then, Is it impossible that make cc downcast of pc what was not upcast before?