[ty] Experiment: Receiver refinements - #29692

from typing import Self, Never, reveal_type
from ty_extensions.experimental import Refines

class TypedStack[Elements = tuple[()]]:
    def __init__(self):
        self._elements = []

    def push[*Ts, T](self: TypedStack[tuple[*Ts]], x: T) -> Refines[TypedStack[tuple[*Ts, T]], None]:
        self._elements.append(x)

    def pop[*Ts, T](self: TypedStack[tuple[*Ts, T]]) -> Refines[TypedStack[tuple[*Ts]], T]:
        return self._elements.pop()

c = TypedStack()

c.push(1)
c.push("foo")
c.push(b"bar")

reveal_type(c.pop())  # Literal[b"bar"]
reveal_type(c.pop())  # Literal["foo"]
reveal_type(c.pop())  # Literal[1]

c.pop()  # error, stack is empty

parser = ArgumentParser()
parser.add_argument("host", type=str)
parser.add_argument("port", type=int)
args = parser.parse_args()

reveal_type(args.host)  # str
reveal_type(args.port)  # int