mypy error with generics typing and singledispatch

[ruomad]

Hello,

Is this normal ?

code
`
from functools import singledispatch
from typing import Any

@singledispatch
def test[T: Any](val: T)-> None:
print("default")

@test.register
def _(val: str) -> None:
print("str")

@test.register
def _(val: float) -> None:
print("float")
`
yields these errors from mypy

Dispatch type "str" must be subtype of fallback function first argument "T"
Dispatch type "float" must be subtype of fallback function first argument "T"

[A5rocks]

Duplicate of #13040