In theory yeah, in practice it's incredibly rare for a class to look like it should be copyable to its own maintainer AND for the maintainer to try to copy it f

In theory yeah, in practice it's incredibly rare for a class to look like it should be copyable to its own maintainer AND for the maintainer to try to copy it from its own methods AND for a linker error to be obscure for them to figure out when they do their first debug build. In fact I'm not sure I've ever encountered this situation. Usually it's pretty obvious if your class should be copyable or not from the outset so it's not common to make the mistake to begin with.