`not isinstance(float_arg, float)` should narrow to int; `not isinstance(complex_arg, complex)` should narrow to float

The typing specs require that a float typed argument also accept int values, and that a complex type argument accept both int and complex values. That implies that, if we have a val typed complex, and isinstance(val, complex) returns false, it can still be an int or float. So,

def test(x: float):
    if not isinstance(x, float):
        reveal_type(x)  # Should reveal int

and,

def test(x: complex):
    if not isinstance(x, complex):
        reveal_type(x)  # Should reveal int | float (or possibly just float)

But they actually get treated as unreachable code and don't reveal anything.

Commencez par reproduire les deux snippets de l’issue et inspecter les tests existants de restriction de type ou l’implémentation qui gère les vérifications isinstance. C’est terminé lorsque le premier exemple révèle int et que le second révèle int | float, ou le rétrécissement acceptable documenté, au lieu de traiter les branches comme inaccessibles.