Y041 is not compatible with mypy 0.990

[kasium]

With mypy 0.990 type promotions was changed.

Before

class Foo:
  a: complex

isinstance(Foo().a, int)  # fine

After

class Foo:
  a: complex

isinstance(Foo().a, int)  # fails

class Foo:
  a: complex | float | int  # raises Y041 

isinstance(Foo().a, int)  # fine

Not sure what to do with this check, but just raining attention.
See python/mypy#14030 and python/typeshed#9130

[ilevkivskyi]

Actually mypy allows type promotions in subtyping so add(1,2) is OK. There are just specific legitimate use cases for a union (related to e.g. isinstance() checks).

[kasium]

@ilevkivskyi thanks. I adjusted the code

[AlexWaygood]

Thanks for opening the issue!

Let's use python/mypy#14030 for discussing this problem for now until we've reached an agreement on what to do; not sure it's helpful to have discussion split across 3 repos.