Problems with "expected overloaded function" when method hinted via Callback Protocol (⇝numpy) #18101
Description
Bug Report
mypy complains about expecting an overloaded function, when a method is hinted by a Callback-Protocol. This technique is used in the numpy stubs, and causes mypy to complain when trying to describe numpy scalars with simple protocols.
To Reproduce
Below is a MWE [mypy-playground], based on how the numpy stubs declare the methods on scalars. Note that [pyright-playground] does not report any issues.
from typing import Protocol, Self, overload
class NumpyFloat:
__add__: "FloatOP"
class FloatOP(Protocol):
@overload
def __call__(self, other: float) -> NumpyFloat: ...
@overload
def __call__(self, other: NumpyFloat) -> NumpyFloat: ...
class SupportsAdd(Protocol):
@overload
def __add__(self, other: float) -> Self: ...
@overload
def __add__(self, other: NumpyFloat) -> Self: ...
x: SupportsAdd = NumpyFloat() # expected overloaded function, got "FloatOP"Concrete example with numpy==2.1.3 (again, pyright reports no errors):
from typing import Protocol, Self, overload
import numpy as np
class TimeDelta(Protocol):
def __sub__(self, other: Self, /) -> Self: ...
class TimeStamp[TD: TimeDelta](Protocol):
@overload
def __sub__(self, other: Self, /) -> TD: ...
@overload
def __sub__(self, other: TD, /) -> Self: ...
x: TimeStamp[np.timedelta64] = np.datetime64("2021-01-01") # ✅
y: TimeStamp[np.float64] = np.float64(10.0) # expected overloaded function, got "_FloatOp[_64Bit]"