PYI061 fixes Literal[None,] | Literal[None,] to None | None

[dscorbett]

Description

The fix for redundant-none-literal (PYI061) converts Literal[None,] | Literal[None,] to None | None, which can raise an exception.

$ cat >pyi061.py <<'# EOF'
from typing import Literal
x: Literal[None,] | Literal[None,]
# EOF

$ python pyi061.py

$ ruff --isolated check --preview --select PYI061 pyi061.py --fix
Found 2 errors (2 fixed, 0 remaining).

$ python pyi061.py                               
Traceback (most recent call last):
  File "pyi061.py", line 2, in <module>
    x: None | None
       ~~~~~^~~~~~
TypeError: unsupported operand type(s) for |: 'NoneType' and 'NoneType'

[VascoSch92]

I think I can fix that. Should be not so difficult.

Another question: I tried to fix the example giving in the doc, and I had another result that the one presented, i.e.,

from typing import Literal
y: Literal[1, 2, 3, "foo", 5, None]

was fixed as

from typing import Literal, Optional
y: Optional[Literal[1, 2, 3, "foo", 5]]

after command ruff --isolated check --preview --select PYI061 scratch.py --fix, but in the docs the fix is given by
Literal[1, 2, 3, "foo", 5] | None.

Which one is the correct/expected fix? Is the fix wrong or the doc :-) ?

FYI: I'm using Python 3.10.14 and Ruff 0.9.6

[InSyncWithFoo]

@VascoSch92 The fix changes depending on what target-version is. For 3.9 (default) and lower, it uses Optional[...]; for 3.10 and higher, it uses ... | None.