The syntax some_enum_value in [list_of_values] should narrow the enum to that list of values.
This is a list extension to #10915 "support narrowing enum values using == and !="
Unlike the == case, there is no equivalent is syntax for lists that will narrow the type.
This example shows the motivation for this feature, as well as the syntax that is expected to work.
from typing import Literal, Union, cast
from enum import Enum
class SomeType(Enum):
a = 1
b = 2
c = 3
LimitType = Union[Literal[SomeType.a, SomeType.b]]
AllowedLimitType = [SomeType.a, SomeType.b]
def inner_check(limit: LimitType) -> None:
pass
def outer_check(some: SomeType) -> None:
if some in [SomeType.a, SomeType.b]:
inner_check(some) # Incompatible type
if some in AllowedLimitType:
inner_check(some) # Incompatible type
if some == SomeType.a or some == SomeType.b:
inner_check(some) # Incompatible type
inner_check(cast(LimitType, some))
if some is SomeType.a or some is SomeType.b:
inner_check(some)
if some == SomeType.a:
inner_check(SomeType.a)
# This would be ideal
# if some in LimitType:
# inner_check(some)
def main() -> None:
outer_check(SomeType.a)
main()
The syntax
some_enum_value in [list_of_values]should narrow the enum to that list of values.This is a list extension to #10915 "support narrowing enum values using == and !="
Unlike the == case, there is no equivalent
issyntax for lists that will narrow the type.This example shows the motivation for this feature, as well as the syntax that is expected to work.