Inconsistent override check doesn't work with generic functions

[grievejia]

Minimal repro:

class Base:
    def filter[T](self, iterable: T) -> T:
        ...

class Derived(Base):
    def filter[T](self, iterable: T) -> T:
        ...

Expected: No error Actual: Class member Derived.filter overrides parent class Base in an inconsistent manner [bad-override]

[grievejia]

Might be a consequence of #73

[stroxler]

Update: we've fixed #73 but this bug persists.

It may still be related, for example the fix might not have handled something related to BoundMethod wrapping