Repository navigation
False positive unreachable for None sub-pattern when matching a union of tuples #22150
Description
Bug Report
When the subject of a match is a union of tuple types, a None sub-pattern is reported as unreachable. This happens even though the literal in the first position narrows the subject to a tuple member whose second item is None.
To Reproduce
Gist URL: https://gist.github.com/mypy-play/ac0323323c7f6ad84103285cca982503
Playground URL: https://mypy-play.net/?mypy=latest&python=3.14&flags=warn-unreachable&gist=ac0323323c7f6ad84103285cca982503
Expected Behavior
No error.
Actual Behavior
error: Subclass of "int" and "NoneType" cannot exist: "NoneType" is final [unreachable]
Your Environment
- Mypy version used: 2.4.0
- Mypy command-line flags:
--warn-unreachable - Mypy configuration options from
mypy.ini(and other config files): None - Python version used: 3.14
Activity