Bug Report

A match on a Boolean literal scrutinee is not exhaustive under the cases True and False. After case False, the remaining type of the scrutinee is still Literal[False]. The same cases on a parameter of type bool are exhaustive.

To Reproduce

def f() -> int:
    match False:
        case True:
            return 1
        case False:
            return 0


def g(c: bool) -> int:
    match True if c else False:
        case True:
            return 1
        case False:
            return 0


def h() -> int:
    match False:
        case True:
            return 1
        case False:
            return 0
        case other:
            reveal_type(other)
            return 2


def k(b: bool) -> int:
    match b:
        case True:
            return 1
        case False:
            return 0

Expected Behavior

No errors, as for k, and other in h unreachable.

Actual Behavior

repro.py:1: error: Missing return statement  [return]
repro.py:9: error: Missing return statement  [return]
repro.py:24: note: Revealed type is "Literal[False]"
Found 2 errors in 1 file (checked 1 source file)

Integer and string literal scrutinees, such as match 1 with case 1, are exhaustive.

Your Environment

• Mypy version used: 2.3.1, 2.4.0 and master (2.5.0+dev.f5d467a7)
• Mypy command-line flags: none
• Mypy configuration options from mypy.ini (and other config files): none
• Python version used: 3.12.13