User generic with TypeVarTuple does not check for minimal type of arguments

[serhiy-storchaka]

The following code:

from typing import *
T = TypeVar('T')
T2 = TypeVar('T2')
Ts = TypeVarTuple('Ts')
class A(Generic[T, T2, *Ts]):
    x: List[T]
    y: List[T2]
    z: Tuple[*Ts]

A[int]

is executed without errors. It is expected to get an error because A requires at least two arguments.

Without TypeVarTuple you get helpful errors.

class B(Generic[T, T2]):
    pass

B[int]
B[int, str, bytes]

TypeError: Too few arguments for <class '__main__.B'>; actual 1, expected 2

TypeError: Too many arguments for <class '__main__.B'>; actual 3, expected 2