`python -m` semantics conflict with `__file__`'s being optional

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2020-11-10.16:52:44.073>
labels = ['interpreter-core', 'type-bug', '3.8', '3.9', '3.10', 'library']
title = "`python -m` semantics conflict with `__file__`'s being optional"
updated_at = <Date 2020-11-10.21:55:49.704>
user = 'https://github.com/wkschwartz'

bugs.python.org fields:

activity = <Date 2020-11-10.21:55:49.704>
actor = 'brett.cannon'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Interpreter Core', 'Library (Lib)']
creation = <Date 2020-11-10.16:52:44.073>
creator = 'William.Schwartz'
dependencies = []
files = []
hgrepos = []
issue_num = 42315
keywords = []
message_count = 1.0
messages = ['380689']
nosy_count = 3.0
nosy_names = ['ncoghlan', 'eric.snow', 'William.Schwartz']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue42315'
versions = ['Python 3.8', 'Python 3.9', 'Python 3.10']