Regardless of mypy's behavior (which isn't impacted by what typing.py does), there's a legitimate complaint here about the runtime behavior: any `__init__` method defined in a Protocol gets silently replaced.

>>> from typing import Protocol
>>> class X(Protocol):
...     def __init__(self, x, y): pass
... 
>>> X.__init__
<function _no_init_or_replace_init at 0x10de4e5c0>

Fixing that won't be easy though, unless we give up on making it impossible to instantiate a Protocol.