Bug Report

I'm not really sure if this is more of a bug or a feature request, but basically I was playing around with TypedDicts and I thought this would be really interesting.

To Reproduce

from typing import TypedDict, Protocol, Callable

class X(TypedDict):
    a: int
    b: str

class GetX[K, V](Protocol):
    def __getitem__(self, key: K, /) -> V: ...

x: X = ...

def f[T, R](k: T, d: GetX[T, R]) -> R:
    return d[k]

reveal_type(x["b"])  # N: Revealed type is "str"
reveal_type(f("b", x))  # N: Revealed type is "object"

Expected Behavior

Both get revealed as str.

Actual Behavior

One gets revealed as object.

Your Environment

Reproduced in mypy-play.

• Mypy version used: 2.4.0
• Mypy command-line flags: N/A
• Mypy configuration options from mypy.ini (and other config files): N/A
• Python version used: 3.12