Union normalized to object when Type requested

[Gricha]

Bug Report

Here's the code snippet:

import typing as t

class Entity(t.Protocol):
    ...

class Foo(Entity):
    ...

class Bar(Entity):
    ...

def foo(a: t.Type[Entity]) -> None:
    ...

foo(t.Union[Foo, Bar, ])

In our code we have some use cases, where we use the type to mark, say, where the exception is happening. The code here only knows that the type will be following a specific protocol (Entity), but at call site we only know a union of possible concrete types.

The code specifically that we have can be worked around, but I wondered whether the behavior change is intended or an accidental bug. We've leveraged it and it worked so far up to 0.770. In 0.780 and 0.790 that code snippet will throw an error:

example_test.py:18: error: Argument 1 to "foo" has incompatible type "object"; expected "Type[Entity]"
Found 1 error in 1 file (checked 1 source file)

Which looks like the Union has been normalized to an object which seems incorrect.

[hauntsaninja]

Duplicate of #9773 (see linked issues)