Python callable typehints with defined initial arguments and undefined (...) arguments after.

callable.py

from collections.abc import Callable
from typing import Any, Concatenate, ParamSpec, TypeVar

from typing_extensions import reveal_type

P = ParamSpec("P")
T = TypeVar("T")


Call = Callable[P, Any]
CallEllipsis = Call[...]  # `...` can be assigned to `P`
reveal_type(CallEllipsis)  # (...) -> Any


Call2 = Callable[Concatenate[int, P], Any]
Call2Ellipsis = Call2[...]  # `...` can be assigned to `P` still
reveal_type(Call2Ellipsis)  # (int, ...) -> Any


Call3 = Callable[Concatenate[T, P], Any]
Call3Ellipsis = Call3[T, ...]  # `T` assigned to `T` as passthrough, `...` assigned to `P`
reveal_type(Call3Ellipsis)  # (T@Call3Ellipsis, ...) -> Any