mypy should give error at the timing when the type alias set multiple `TypeVarTuple`-based type parameters is defined but not used

[hyperkai]

*Memo:

• mypy test.py
• mypy 1.19.1
• Python 3.14.0

Defining the type alias set multiple TypeVarTuple-based type parameters, mypy doesn't give error while mypy gives the error, when using the type alias as shown below so mypy should give error at the timing when the type alias set multiple TypeVarTuple-based type parameters is defined but not used:

*Memo:

• pyright and pyrefly give error at the timing when the type alias set multiple TypeVarTuple-based type parameters is defined.

''' New syntax '''
type TA[*Ts1, *Ts2] = tuple[*Ts1] | tuple[*Ts2] # No error
''' New syntax '''

''' Old syntax '''
# from typing import TypeAlias, TypeVarTuple

# Ts1 = TypeVarTuple('Ts1')
# Ts2 = TypeVarTuple('Ts2')

# TA: TypeAlias = tuple[*Ts1] | tuple[*Ts2] # No error
''' Old syntax '''

v: TA[*tuple[int, ...], *tuple[str, ...]] # Error

error: More than one variadic Unpack in a type is not allowed

[aviralgarg05]

I would like to solve this issue, please assign me this issue

[A5rocks]

Feel free to fix things even if you aren't assigned!