In the following example the last line throws as 'NameError: name 'Level1A' is not defined' for both 3.7 and 3.8

I assumed that Level1A should already be in scope while defining the insides of Level1B. But it isn't.
Is this a bug, or am I missing something?


from typing import List, Union


class Level0A:
    pass


class Level0B:
    class Level1A:
        subs: List[Level0A]

    class Level1B:
        subs: List[Level1A]

This is even a better example:

Level1A is available to inherit from, but not to type with.

Example:

from typing import List


class Level0A:
    pass


class Level0B:
    class Level1A:
        pass

    class Level1B(Level1A):
        pass

    class Level1C:
        test: Level1A

> I assumed that Level1A should already be in scope while defining 
> the insides of Level1B. But it isn't.

That analysis is correct.  Class namespaces don't nest like functions do.  The "enclosing" namespace is globals, not the surrounding class.

This isn't a bug, but it is understandable why you might assume otherwise.