ruff

296d67a4 - Special-case value-expression inference of special form subscriptions (#16877)

Special-case value-expression inference of special form subscriptions (#16877) ## Summary Currently for something like `X = typing.Tuple[str, str]`, we infer the value of `X` as `object`. That's because `Tuple` (like many of the symbols in the typing module) is annotated as a `_SpecialForm` instance in typeshed's stubs: https://github.com/astral-sh/ruff/blob/23382f5f8c7b4e356368cdeb1049b8c1910baff3/crates/red_knot_vendored/vendor/typeshed/stdlib/typing.pyi#L215 and we don't understand implicit type aliases yet, and the stub for `_SpecialForm.__getitem__` says it always returns `object`: https://github.com/astral-sh/ruff/blob/23382f5f8c7b4e356368cdeb1049b8c1910baff3/crates/red_knot_vendored/vendor/typeshed/stdlib/typing.pyi#L198-L200 We have existing false positives in our test suite due to this: https://github.com/astral-sh/ruff/blob/23382f5f8c7b4e356368cdeb1049b8c1910baff3/crates/red_knot_python_semantic/resources/mdtest/annotations/annotated.md?plain=1#L76-L78 and it's causing _many_ new false positives in #16872, which tries to make our annotation-expression parsing stricter in some ways. This PR therefore adds some small special casing for `KnownInstanceType` variants that fallback to `_SpecialForm`, so that these false positives can be avoided. ## Test Plan Existing mdtest altered. Cc. @MatthewMckee4