Just to clarify, on Python 2 the problem with copying classes is not specific to generics, any class with a metaclass other than type can't be copied:

>>> class M(type): pass
>>> class C(object):
...     __metaclass__ = M
>>> from copy import copy
>>> copy(C)  # obscure TypeError

But the ad-hoc __copy__ on metaclass fix that is currently used clashes with copying instances of generic classes.

If you mean copy_reg.dispatch_table, then no, __copy__ is searched before. But there is an internal API copy._copy_dispatch (see new commit) that works. If you are fine with this, then I am also fine.

Oh, wait, but we don't need __copy__. OK, then I will make a cleaner fix now.

Actually, copy_reg explicitly says that copy_reg is not intended for use with classes, therefore I think the _copy_dispatch fix for Python 2 is OK.