Number is not compatible with int

[theRealProHacker]

I tried to hold the code as minimal as possible

num: Number = 0

If we run mypy over this:

error: Incompatible types in assignment (expression has type "int", variable has type "Number")

This is unexpected. There shouldn't be an error because Number>int or in other words isinstance(0, Number) is True.
Instead, there should be no error.
I can't tell if this is a bug in mypy, but I think it rather is a typing problem.

Python Version 3.10.1
OS: Windows 10 (Although, I think this shouldn't make a difference)

[AlexWaygood]

This is a very well-known problem. For a ground-up explanation of what's going on here, you might like my StackOverflow answer to this question here: https://stackoverflow.com/questions/69334475/how-to-hint-at-number-types-i-e-subclasses-of-number-not-numbers-themselv

For pre-existing discussions on what to do about this, you may be interested in:

• int is not a Number? mypy#3186
• https://discuss.python.org/t/numeric-generics-where-do-we-go-from-pep-3141-and-present-day-mypy/17155
• Use abstract types from numbers #7217