Mypy fails to correctly validate Type[T]

Dear all,

Consider the example code below:

from typing import Type, TypeVar, Tuple

T = TypeVar('T')


def func(a: T, a_type: Type[T]) -> Tuple[T, Type[T]]:
    return a, a_type


a1, a1_type = func(1, int)
a2, a2_type = func(1, str)

reveal_type(a1)
reveal_type(a1_type)
reveal_type(a2)
reveal_type(a2_type)

The first call to func shouldn't give rise to any issues, while the second one should complain about an incompatible type in the a_type argument (as type(1) is not str).

Yet, whenever I run mypy (Python 3.7; mypy 0.770; MacOS 10.15.1) it fails to produce any errors, even going as far to infer the type of a2 as object instead of int.

>>> mypy test.py
test.py:13: note: Revealed type is 'builtins.int'
test.py:14: note: Revealed type is 'Type[builtins.int]'
test.py:15: note: Revealed type is 'builtins.object'
test.py:16: note: Revealed type is 'Type[builtins.object]'

Is anyone familiar with this issue?

Start by running the provided example with mypy and comparing the reported types and diagnostics with the expected result. Trace the type inference and argument validation path for Type[T]; done means rejecting func(1, str), accepting func(1, int), and inferring the revealed types correctly.