new rule - `TypeVar` redefinition

[DetachHead]

from typing import TypeVar

T = TypeVar("T")
T = TypeVar("T") # should be an error

[jorenham]

is this unsound?

[DetachHead]

i figured it's likely a mistake, but thinking about it some more i guess it could be useful if you want to reuse T but with a different bound/variance for different functions/classes (like you can with the proper syntax)