Summary

Rule UP007 which replaces Union type hints with | and Optional[foo] with foo | None crashes on all versions of Python including the latest ones under the very specific circumstance of replacing Optional[typing.NamedTuple] with typing.NamedTuple | None.

The error is:

TypeError: unsupported operand type(s) for |: `function` and `NoneType`

I tested on Python 3.11, 3.13 saw identical behavior in all cases. It does work fine on 3.14 due to deferred type evaluation.

Version

ruff 0.11.13 as installed from uv