0.930: mypyc --help crashes with KeyError: __file__

[asottile]

Bug Report

$ mypyc --help
Traceback (most recent call last):
  File "/tmp/y/venv/bin/mypyc", line 5, in <module>
    from mypyc.__main__ import main
  File "mypyc/__main__.py", line 18, in <module>
KeyError: '__file__'

To Reproduce

1. mypyc --help

Expected Behavior

not to crash

(Write what you thought would happen.)

Actual Behavior

see above

(Write what happened.)

Your Environment

• Mypy version used: 0.930
• Mypy command-line flags: --help
• Mypy configuration options from mypy.ini (and other config files): n/a
• Python version used: 3.8.10
• Operating system and version: ubuntu 20.04

[A5rocks]

This is a known regression: #11700 (comment)

There will be a 0.931 release that solves this sooner or later, I believe.

[hauntsaninja]

Thanks for the report. This is obviously a pretty bad bug. Fixed on master and tests have been added to the wheel build to catch this kind of thing going forward.

Also linking mypyc/mypyc#912 (comment)