(🐞) false narrowing with reassignment in loop

[KotlinIsland]

a: int | None
a = None
for i in range(10):
    reveal_type(a)  # "None" and also "int | None"
    if a:
        print(a)  # error: unreachable
    a = i

Also:

a = None
for b in [1, 2]:
    if a is None:
        a = b
        continue
    print("hi")  # false unreachable error

[sobolevn]

This can be fixed by:

a: int | None = None
for b in [1, 2]:
    if a is None:
        a = b
        continue
    print("hi")  # ok

The other question is: why a is not infered to be None | int?

[KotlinIsland]

It is, if you put reveal_type after the loop it reveals as int | None

Perhaps it is inferring as int | None, but only past line 4, not considering the loop.

[KotlinIsland]

@sobolevn It's not just the inference, I've updated the OP with a much better example.