Bug - Type aliasing typing.Tuple is treated as if the empty Tuple is being aliased

This is a bug report.

Type aliasing typing.Tuple is treated as if the empty tuple (typing.Tuple[()]) is being aliased.

Here is some sample code that converts Polar coordinates into Cartesian:

import math
import typing

Tuple = typing.Tuple


def cartesian(r: int, θ: int) -> Tuple[float, float]:
    rad = math.radians(θ)
    return r*math.cos(rad), r*math.sin(rad)


r = 12
θ = 195

x,y = cartesian(r, θ)
print(f"({r}, {θ}°) = ({x:.2f}, {y:.2f})")

$ python3 example.py 
(12, 195°) = (-11.59, -3.11)
$ mypy example.py 
example.py:7: error: Bad number of arguments for type alias, expected: 0, given: 2
Found 1 error in 1 file (checked 1 source file)

What is the actual behavior/output?

example.py:7: error: Bad number of arguments for type alias, expected: 0, given: 2
Found 1 error in 1 file (checked 1 source file)

What is the behavior/output you expect?

Success: no issues found in 1 source file

Such as when from typing import Tuple is used instead.

What are the versions of mypy and Python you are using?

I'm using mypy version 0.77 installed using pip and Python 3.7.7 instead via homebrew on macOS Catalina 10.15.4.

Do you see the same issue after installing mypy from Git master?

Yes.

What are the mypy flags you are using? (For example --strict-optional)

None.

Additional details

It might be related to #8273. I know Tuple and Callable are both mentioned in PEP 484 as being different.

example.py の再現から始め、追加の flags を付けずに mypy を実行し、レポートで説明されている aliased typing.Tuple アノテーションと直接インポートを比較します。aliased 形式が期待される “Success: no issues found” の出力で正常に型チェックされれば、作業は完了です。