exc_info inside an except clause will always return not None

When calling sys.exc_info from inside an except block, the returned variables will never be None, as defined by the standard library.

However, when trying to use one of the returned variables, mypy throws an error as the type is set as Optional[Type[BaseException]].

Here's the output:

> mypy test.py
test.py:8: error: Item "None" of "Optional[Type[BaseException]]" has no attribute "__name__"
Found 1 error in 1 file (checked 1 source file)

Here's the code I'm using to test:

import sys

# This causes the error
try:
    raise Exception
except Exception:
    ex, val, _ = sys.exc_info()
    print(f"Failed: {ex.__name__}: {val}")  # Line 8

# This does not
try:
    raise Exception
except Exception:
    ex, val, _ = sys.exc_info()
    if ex is not None:  # Pointless comparison
        print(f"Failed: {ex.__name__}: {val}")

I'm not sure if this is a bug or a missing feature?

Beginne mit der test.py-Reproduktion und vergleiche den von mypy abgeleiteten Typ für sys.exc_info() innerhalb des except-Blocks mit dem im Issue beschriebenen Verhalten der Standardbibliothek. Bestätige das erwartete Ergebnis, indem du mypy für das Beispiel ausführst: Der Zugriff auf ex.name sollte keine sinnlose None-Prüfung erfordern.