from typing import Any, Tuple, TypeVar, Union
from pynction import just
from pynction.monads.maybe import DoMaybe, Maybe, do as do_maybe

def a() -> Maybe[int]:
    return just(3)

def b() -> Maybe[str]:
    return just("foo")

@do_maybe
def f() -> DoMaybe[Union[int, str], Tuple[int, str]]:
    x = yield a()
    y = yield b()
    return (x, y)

T = TypeVar("T")

def gen(x: Maybe[T]) -> DoMaybe[T, T]:
    t = yield x
    return t

@do_maybe
def g1() -> DoMaybe[Union[int, str], Tuple[int, str]]:
    x = yield from gen(a())
    y = yield from gen(b())
    return (x, y)  # no error

DoMaybeAny = DoMaybe[Any, T]

@do_maybe
def g2() -> DoMaybeAny[Tuple[int, str]]:
    x = yield from gen(a())
    y = yield from gen(b())
    return (x, y)  # no error

@do_maybe
def g3() -> DoMaybeAny[Tuple[int, str]]:
    x = yield from gen(a())
    y = yield from gen(b())
    return (y, x)  # error Tuple[str, int] vs Tuple[int, str]