Overzealous truthy-bool check in finally block

Bug Report

If a variable's type is narrowed from potentially-falsey to definitely-truthy during a try block, and that variable is truth-tested during a finally block, the truthy-bool check raises an error even though the variable could in fact be false (if an exception is raised in the try block before the narrowing occurs).

To Reproduce

class A:
    def __init__(self):
        import random
        if random.randint(0, 1):
            raise ValueError
    def close(self): pass

def fn() -> None:
    a: A | None = None
    try:
        a = A()
        print(a)
    finally:
        if a:
            a.close()

fn()

Expected Behavior

Since a might still be None (if A.__init__ raises ValueError) I would expect mypy to not flag the if statement as redundant.

Actual Behavior

$ mypy --enable-error-code=truthy-bool t.py
t.py:14: error: "a" has type "A" which does not implement __bool__ or __len__ so it could always be true in boolean context  [truthy-bool]
Found 1 error in 1 file (checked 1 source file)

If I add a reveal_type(a) line just before if a:, then I get two revealed types:

t.py:14: note: Revealed type is "Union[t.A, None]"
t.py:14: note: Revealed type is "t.A"

which makes me suspect this is an issue where finally statements are desugared into an after-try and an after-except, with different narrowings applied to each one, and truthy-bool is only complaining about one of those.

Your Environment

$ mypy --version
mypy 1.5.1 (compiled: yes)
$ python --version
Python 3.11.5

Eseguire l'esempio fornito con mypy 1.5.1 e --enable-error-code=truthy-bool, quindi esaminare il narrowing nel blocco finally e il controllo truthy-bool coinvolto nelle diagnosi segnalate. Il lavoro è completato quando l'esempio non segnala più un errore di truthiness ridondante, preservando al contempo il narrowing corretto e le diagnosi per gli altri casi di finally.