Copy does _not_ affect compilation, only type checking. If you add Copy to a type, the generated code will not change. If you remove Copy from a type, the code

Copy does _not_ affect compilation, only type checking. If you add Copy to a type, the generated code will not change. If you remove Copy from a type, the code will either stop compiling or be exactly the same. The difference between a copy and a move is whether you can still use the old value, and this is checked in the type system.