Can't infer tuple inside match case

[racinmat]

Bug Report

(A clear and concise description of what the bug is.)

To Reproduce

from typing import Any, Union

Sentence = Union[str, tuple[str, str]]
Sample = Union[Sentence, bytes, bytearray, dict[str, Any]]

def instance2sentence(i: Sample) -> Sentence:
 match i:
 case {"text": j}:
 return instance2sentence(j)
 case [str(), str()]:
 return tuple(i) # this fails
 case str():
 return i
 case _:
 raise AssertionError(f"Unsupported instance type")


instance2sentence("sentence1")
instance2sentence(("sentence1", "label1"))
instance2sentence({"text": "text sample 3"})

Expected Behavior

The code should pass, because the pattern matching makes sure the tuple(i) is only tuple[str, str].

Actual Behavior

main.py:11: error: Incompatible return value type (got "tuple[object, ...]", expected "str | tuple[str, str]") [return-value]

Your Environment

Mypy playground: https://mypy-play.net/?mypy=latest&python=3.13&gist=e3671ab907e180d0cc6b60aefeec2052

[hauntsaninja]

#20744 fixes the match statement relevant part of this.

There is the remaining issue that mypy currently does not accept the following:

def foo(x: tuple[str, str]) -> tuple[str, str]:
 return tuple(x)