type not inferred in application of higher-order function to a generic function

[rwbarton]

from typing import TypeVar, Callable
S = TypeVar('S')
def apply(f: Callable[[int], S]) -> S: pass
def g(x: S) -> S: pass
y = apply(g) # E: Argument 1 to "apply" has incompatible type Callable[[S], S]; expected Callable[[int], S]
reveal_type(y) # E: Revealed type is 'S`-1'

The call to apply should type check, with both types S and the type of y being int.

I encountered this sort of situation in mypy/codec/pytokenize.py in the lines

tokenprog, pseudoprog, single3prog, double3prog = map(
    re.compile, (Token, PseudoToken, Single3, Double3))

#1471 was an attempt to fix this, but since it fixes this case but not #1506, I'm filing these as two related but distinct issues.

[davidhalter]

This is working now. So I feel like this issue should be closed.

See https://mypy-play.net/?mypy=latest&python=3.12&gist=2265ae341b2994f28577afc8788c0879

[hauntsaninja]

Thanks!