can't compose @future_safe coroutines that specify picky exceptions

Bắt đầu bằng cách chạy ví dụ mre.py được cung cấp với returns[compatible-mypy]==0.25.0 và mypy, sau đó kiểm tra hành vi kiểu của future_safe và FutureResult.bind. Hoàn thành khi hai coroutine kết hợp được với nhau mà không có lỗi kiểu, đồng thời vẫn giữ các trường hợp ConnectionError và ZeroDivisionError riêng biệt.

Given coroutines coro1, coro2:

@future_safe(exceptions=(ConnectionError,))
async def coro1(c: int | None) -> int:
    if c is None:
        raise ConnectionError("not connected")
    await asyncio.sleep(0)  # emulate I/O
    return c


@future_safe(exceptions=(ZeroDivisionError,))
async def coro2(n: int) -> float:
    await asyncio.sleep(0)  # emulate I/O
    return 1 / n

I want to combine them via bind: coro1(c).bind(coro2). It results in type error:

$ uvx --with 'returns[compatible-mypy]==0.25.0' mypy mre.py; ./mre.py
mre.py:30: error: Argument 1 to "bind" of "FutureResult" has incompatible type "Callable[[int], FutureResult[float, ZeroDivisionError]]"; expected "Callable[[int], KindN[FutureResult[Any, Any], float, ConnectionError, Any]]"  [arg-type]

where mre.py:

#!/usr/bin/env -S uv run --script
# /// script
# requires-python = ">=3.11"
# dependencies = [
#     "returns >=0.25.0",
# ]
# ///
from typing import assert_never
from returns.result import Success, Failure
from returns.io import IOSuccess, IOFailure
from returns.future import future_safe


@future_safe(exceptions=(ConnectionError,))
async def coro1(c: int | None) -> int:
    if c is None:
        raise ConnectionError("not connected")
    await asyncio.sleep(0)  # emulate I/O
    return c


@future_safe(exceptions=(ZeroDivisionError,))
async def coro2(n: int) -> float:
    await asyncio.sleep(0)  # emulate I/O
    return 1 / n


async def run() -> None:
    for c in [2, 0, None]:
        match await coro1(c).bind(coro2):
            case IOSuccess(Success(r)):
                assert r == 1 / 2, r
            case IOFailure(Failure(ZeroDivisionError(args=(msg,)))):
                assert msg == "division by zero", msg
            case IOFailure(Failure(ConnectionError(args=(msg,)))):
                assert msg == "not connected", msg
            case _ as unreachable:
                assert_never(unreachable)  # type: ignore[arg-type]


if __name__ == "__main__":
    import asyncio

    asyncio.run(run())

If picky exceptions are removed:

@future_safe
async def coro1(c: int | None) -> int: ...

@future_safe
async def coro2(n: int) -> float: ...

I get the desired behavior that coroutines are composed without type errors but these declarations catch too much.