Description
Bug Report
This may be related to #12211.
When extracting a type annotation like -> t.AnyStr | int to a t.Union alias, mypy fail to detect incorrect return types.
The actual problem for me was that annotating flask view functions with ResponseValueType did not find obvious return type violations, but (as I found out during writing of this issue) a workaround seems to have been added.
I'm unsure what to expect of mypy here but silently allowing everything seems like a big hazard to me.
To Reproduce
See the functions foo2 and bar2 in the following gist:
https://mypy-play.net/?mypy=latest&python=3.11&gist=04f598b90124f58021cf19209a7df967.
Expected Behavior
the return statements of foo2 and bar2 should cause an error, either the same error as foo and bar or the same as foo3 and bar3.
Actual Behavior
foo2 and bar2 don't cause an error
Your Environment
- Mypy version used: 1.4.1
- Mypy command-line flags: None
- Mypy configuration options from
mypy.ini(and other config files): None - Python version used: 3.11