Iterating over cls.__dict__ in classmethod causes RuntimeError when printing __annotations__

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2022-03-05.15:33:42.140>
labels = ['type-bug', '3.10', '3.11']
title = 'Iterating over cls.__dict__ in classmethod causes RuntimeError when printing __annotations__'
updated_at = <Date 2022-03-07.06:42:58.233>
user = 'https://github.com/PythonFZ'

bugs.python.org fields:

activity = <Date 2022-03-07.06:42:58.233>
actor = 'larry'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = []
creation = <Date 2022-03-05.15:33:42.140>
creator = 'PythonF'
dependencies = []
files = []
hgrepos = []
issue_num = 46930
keywords = []
message_count = 3.0
messages = ['414582', '414583', '414639']
nosy_count = 3.0
nosy_names = ['larry', 'JelleZijlstra', 'PythonF']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue46930'
versions = ['Python 3.10', 'Python 3.11']