[Python] Type hint two function parameters to constrain them both to the same type and reject...

I would like to annotate both parameters of a function - supposed to perform simple comparison betweeen them - in order to indicate that their types should be be the same and should support simple equality comparison.

The second part should be normally trivial, as every type implicitly inherits from object which promises to support this

class object:

def __eq__(self, value: object, /) -> bool: ...


and yet numpy.ndarray does not, because its parent class overrides the method as

class _ArrayOrScalarCommon:

def __eq__(self, other: Any) -> Any: ...


in order to return arrays of booleans with the shape of the argument instead of a unique boolean. This should be already marked as incompatible override as it represents a violation of the LSP. Nevertheless, I want to enforce correctness of the function at type level so that users know that it should not be used with two arguments of type numpy.ndarray or of different types.

Simple protocol annotation does not work

from typing import Protocol
from numpy import array


class SupportsSimpleComparison(Protocol):

def __eq__(self, other: object, /) -> bool: ...


def check_equal(a: SupportsSimpleComparison, b: SupportsSimpleComparison) -> bool:
return a == b

# no errors reported from pyright
check_equal(array([0, 0, 0]), array([0, 0, 1]))
check_equal(1.0, "hello world")


nor does making the function generic with a type variable bound to the protocol

T = TypeVar("T", bound=SupportsSimpleComparison)


def check_equal(a: T, b: T) -> bool:
return a == b


# no errors reported from pyright
check_equal(array([0, 0, 0]), array([0, 0, 1]))
check_equal(1.0, "hello world")

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