Case class copy() method abstraction

Question

I would like to know if it is possible to abstract the copy method of case classes. Basically I have something like sealed trait Op and then something like

Answer 1

1. What would be the benefit of a compiler generated copy method for case classes without any arguments? This would just return a new Foo, and not copy anything.
2. To quote Lukas Rytz (I believe he implemented it):

The copy methods are only generated if there is no member named"copy" in the class, directly defined or inherited.