Faulty type narrowing with value restrictions

Bug Report

When passing an empty list directly into a value restricted generic function, the inferred return type can end up being too narrow.

To Reproduce

from typing import TypeVar


TV = TypeVar("TV", str, int)


def foo(x: list[TV]) -> list[TV]:
    return x
    

# Should be: builtins.list[builtins.str] | builtins.list[builtins.int]
reveal_type(foo([]))  # "builtins.list[builtins.str]"

https://mypy-play.net/?mypy=latest&python=3.10&flags=strict&gist=129ba2fed0c6ba1a861149f944db3420

Expected Behavior

I would expect the revealed type to either be builtins.list[builtins.str] | builtins.list[builtins.int].

Alternatively, having this result in an error of some sort would be fine. As a reference, when assigning the empty list first, it becomes a list[Any] instead of a list[<nothing>]. This results in the revealed type being list[Any], but also an error along the lines of Need type annotation for "l" (hint: "l: List[<type>] = ...").

Actual Behavior

The revealed type was builtins.list[builtins.str]

Beginne mit dem verknüpften mypy-play-Reproduzierer und verfolge die Behandlung leerer Listenargumente bei der Inferenz eines wertbeschränkten TypeVar. Vergleiche den abgeleiteten Typ mit der erwarteten Union und dem im Issue beschriebenen akzeptablen Diagnoseverhalten. Erledigt ist es, wenn das Beispiel nicht mehr fälschlicherweise auf list[str] eingeengt wird.