The revealed narrowed type is unexpected, and there is a false negative:

from enum import IntEnum

class E(IntEnum):
    X = 1

def f(x: int) -> None:
    if x == E.X:
        print(x.value)  # No mypy error, but fails at runtime
        reveal_type(x)  # "Literal[E.X]"

f(1)

I'd expect the revealed type to be int, since that's the correct runtime type. IntEnum values are equal to the corresponding int objects:

print(1 == E.X)  # True

Also, x.value should be flagged as an error, since it fails at runtime.

If this needs special casing for IntEnums, it's fine. We already special case enums in various ways.