False-positive "Overloaded function signatures overlap with incompatible return types"

[henzef]

Bug Report

In the minimal example below, I get an unexpected "Overloaded function signatures overlap with incompatible return types" error from mypy. The example is taken from a general "wait for an event or a message" function that I use in my codebase. It allows requesting one or multiple event or message types.

To Reproduce

class Message:
    pass


class Event:
    pass


_WaitableTypes = Union[type[Message], type[Event]]
_MessageT1 = TypeVar("_MessageT1", bound=Message)
_MessageT2 = TypeVar("_MessageT2", bound=Message)


# Single message
@overload
def wait_for(
    msg_type: type[_MessageT1],
) -> _MessageT1:
    ...


# Two messages (arbitrary iterable of messages is also supported, but not relevant in this example)
@overload
def wait_for(
    msg_type: tuple[type[_MessageT1], type[_MessageT2]],
) -> Union[_MessageT1, _MessageT2]:
    ...


# List of events
@overload
def wait_for(
    msg_type: Iterable[type[Event]],
) -> Event:
    ...


def wait_for(
    msg_type: Union[_WaitableTypes, Iterable[_WaitableTypes]],
) -> Union[Message, Event]:
    return ...  # type: ignore

Expected Behavior

mypy does not complain

Actual Behavior

mypy reports "error: Overloaded function signatures 2 and 3 overlap with incompatible return types [misc]"

Your Environment

• Mypy version used: 1.0.1
• Mypy command-line flags: none
• Mypy configuration options from mypy.ini (and other config files): none
• Python version used: 3.9

[sterliakov]

Fixed via #17392 (since mypy 1.11.0)