Crash report

The following example triggers a segfault on the latest stable Python3.8.14. I think there might be a bug in asyncio.Future.remove_done_callback().

import asyncio
fut = asyncio.Future()
fut.add_done_callback(str)
for str in range(63):
    fut.add_done_callback(id)

class evil:
    def __eq__(self, other):
        fut.remove_done_callback(other)
fut.remove_done_callback(evil())

Error messages

Segmentation fault (core dumped)

Your environment

• CPython versions tested on: Python 3.8.14, Python 3.9.0, main branch 68c46ae
• Operating system and architecture: [GCC 7.5.0] on linux