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Non overlapping inclusion check for literal types #11313
Description
Right now mypy spots an error on the first if condition but it would be great if it could also complain on the second one which seems a better expression of the first test:
from typing import Literal
literal_t = Literal['a', 'b', 'c']
x: literal_t = 'b'
if x == 'a' or x == 'd': ...
if x in ('a', 'd'): ...mypy version:
$ mypy --version
mypy 0.920+dev.bbea3b56297d3d966b9a98900c218df6616fec85
Activity
sobolevn commentedon Oct 12, 2021
incheck is not support right now, as far as I remember. It could be a cool feature. And quite easy one.We can just translate
x in ('a', 'b')expression intox == 'a' or x == 'b'. And everything should work the same way.I will look into it.
sobolevn commentedon Nov 9, 2021
Turned out it is not as easy. Simple "translate" did not work. Several reasons:
inis not identical to two==. There might be__contains__defined, but not__eq__. Or they might be incompatibleintgr commentedon Aug 19, 2022
This issue title is misleading, should be renamed to mention
inoperator, nothing to do with literal types.sterliakov commentedon Dec 20, 2024
Similar/duplicate of #3229?