Incorrect handling of default arguments for type Type with Typevars

[AMDmi3]

Consider a function which takes type and returns instance of that type. This is handled correctly by mypy:

from typing import Type, TypeVar

MyType = TypeVar('MyType', str, int)

def func(t: Type[MyType]) -> MyType:
    return t()

However, if I set default argument for t, mypy fails:

from typing import Type, TypeVar

MyType = TypeVar('MyType', str, int)

# error: Incompatible default for argument "t" (default has type "Type[str]", argument has type "Type[int]")
def func(t: Type[MyType] = str) -> MyType:
    return t()

from typing import Type, TypeVar

MyType = TypeVar('MyType', str, int)

# error: Incompatible default for argument "t" (default has type "Type[int]", argument has type "Type[str]")
def func(t: Type[MyType] = int) -> MyType:
    return t()

from typing import Type, TypeVar

MyType = TypeVar('MyType')

# error: Incompatible default for argument "t" (default has type "Type[int]", argument has type "Type[MyType]")
def func(t: Type[MyType] = int) -> MyType:
    return t()

IMO that's a bug. Without TypeVar it works correctly though:

from typing import Type, TypeVar, Union

def func(t: Type[Union[str, int]] = str) -> Union[str, int]:
    return t()

[emmatyping]

This is a duplicate of #4236. Please make sure to search the issue tracker when reporting bugs (using a couple of words such as "default" and "generic"/"typevar" then scanning through the listed issues works well).