Inconsistent narrowing for `builtins.type` and `typing.Type`

The following difference is due to Mypy handling typing.Type via TypeType, for which it does not try to create an intersection, and builtins.type as an Instance, for which it does:

# flags: --python-version 3.9 --warn-unreachable

from typing import Type

t1: Type
t2: type
class C: ...

if isinstance(t1, C):
    reveal_type(t1)  # E: Statement is unreachable
if isinstance(t2, C):
    reveal_type(t2)  # N: Revealed type is "__main__.<subclass of "type" and "C">"

I encountered this problem when working on #16330, which affects type checking a sphinx function.

Interestingly, things are consistent when annotating explicitly with Any:

# flags: --python-version 3.9 --warn-unreachable

from typing import Any, Type

t1: Type[Any]
t2: type[Any]
class C: ...

if isinstance(t1, C):
    reveal_type(t1)  # E: Statement is unreachable
if isinstance(t2, C):
    reveal_type(t2)  # E: Statement is unreachable

So, Mypy maybe misunderstands t2: type?

Comienza con el reproducer del issue usando la configuración indicada de Python 3.9 y --warn-unreachable. Rastrea cómo Mypy estrecha typing.Type mediante TypeType frente a builtins.type mediante Instance, y después compara el comportamiento con los ejemplos explícitos de Any. Se considera terminado cuando se haya resuelto el estrechamiento inconsistente y los casos mostrados produzcan diagnósticos y tipos revelados coherentes.