Proposal: Allow Typevartuple unpacking in unions

[Eneg]

If a PEP does emerge, perhaps it could also be expanded to address this:

Parametrizing **P with [*Ts]

As per PEP 646, Callable supports unpacking a TypeVarTuple in its parameter list to capture positional argument types. This functionality seems to be lost when we alias a callable using **P: from collections import abc from typing import Any type CoroFunc[**P, T] = abc.Callable[P, abc.Coroutine[Any, Any, T]] def accepts_func[*ArgsTs]( func: abc.Callable[[object, *ArgsTs], abc.Coroutine[Any, Any, object]], func2: CoroFunc[[object, *ArgsTs], object], # error: TypeVarTuple is not allow…