(🐞) always-true/always-false doesn't activate until it's truth is checked

[KotlinIsland]

test.py:

from typing import Literal


def foo(a: Literal[True]) -> None:
    ...


FOO: bool
foo(FOO)  # error: Argument 1 to "foo" has incompatible type "bool"; expected "Literal[True]"  [arg-type]
reveal_type(FOO)  # note: Revealed type is "builtins.bool"
if not FOO:
    pass
reveal_type(FOO)  # note: Revealed type is "Literal[True]"
if not FOO:
    pass
import test2

test2.py:

from test import FOO

reveal_type(FOO)  # note: Revealed type is "builtins.bool"
if FOO:
    pass
reveal_type(FOO)  # note: Revealed type is "Literal[True]"

> mypy --always-true FOO test.py

[Zeckie]

Can you explain what you think is wrong, and why?

eg. is it that due to --always-true FOO on command line, the variable FOO should always be treated as Literal[True]?

Is this going to have flow on effects, such as having the code inside if not FOO: being unreachable?

[KotlinIsland]

@Zeckie You can read about the expected functionality here

There are some negative consequences to this functionality, such as #11364