Open
Description
Bug Report
In a rather convoluted nesting, I found that a Union was turned into builtins.object.
To Reproduce
import typing as t
_T = t.TypeVar("_T")
_P = t.ParamSpec("_P")
async def works() -> None:
async def callback(
cb: t.Callable[_P, t.Union[t.Awaitable[_T], _T]],
*args: _P.args, **kwargs: _P.kwargs
) -> _T:
raise NotImplementedError()
def make_t() -> t.Union[
t.Callable[[], t.Coroutine[t.Any, t.Any, int]],
t.Callable[[], int]
]:
raise NotImplementedError()
t = make_t()
t_cb = await callback(t)
reveal_type(t_cb) # note: Revealed type is "builtins.int"
async def fails() -> None:
async def callback(
cb: t.Callable[_P, t.Union[t.Awaitable[_T], _T]],
*args: _P.args, **kwargs: _P.kwargs
) -> _T:
raise NotImplementedError()
def make_t() -> t.Union[
t.Callable[[], t.Coroutine[t.Any, t.Any, t.Union[int, str]]],
t.Callable[[], t.Union[int, str]]
]:
raise NotImplementedError()
t = make_t()
t_cb = await callback(t)
reveal_type(t_cb) # Revealed type is "builtins.object"Gist URL: https://gist.github.com/mypy-play/f932b06f9d8638c2b0c711f8e4048348
Playground URL: https://mypy-play.net/?mypy=latest&python=3.11&gist=f932b06f9d8638c2b0c711f8e4048348
In the example you can see two example functions works and fails which are the exact same except for int in works was replaced with Union[int, str] in fails. Both end with a reveal_type.
Expected Behavior
worksshould revealbuiltins.intfailsshould revealUnion[builtins.int, builtins.str]
Actual Behavior
worksrevealsbuiltins.int(as expected)failsrevealsbuiltins.object(unexpected)
(here's the mypy output of the gist)
main.py:23: note: Revealed type is "builtins.int"
main.py:41: note: Revealed type is "builtins.object"
Success: no issues found in 1 source file
Your Environment
$ python -VV
Python 3.11.0 (main, Nov 2 2022, 13:45:57) [GCC 11.3.0]
$ pip freeze | grep 'mypy\|typing'
mypy==1.3.0
mypy-extensions==1.0.0
typing_extensions==4.5.0Related
I think there's a whole bunch of related issues already, but I wanted to share this example to potentially validate a future fix.