bpo-42904: Change search order of typing.get_type_hints eval

[Fidget-Spinner]

https://bugs.python.org/issue42904

[Fidget-Spinner]

@gvanrossum Oh no, I realised I shadowed the name of the original test in the previous PR, causing test_get_type_hints_classes to not run, sorry :(. Now that I changed the name, the test fails. This was the scenario we were specifically discussing about at #24201 (comment).

    class A(Generic[T]):
        __annotations__ = dict(
            some_b='B'
        )


    class B(Generic[T]):
        class A(Generic[T]):
            pass

        __annotations__ = dict(
            my_inner_a1='B.A',
            my_inner_a2=A,
            my_outer_a='A'  # unless somebody calls get_type_hints with localns=B.__dict__
        )

So it seems we do need to swaplocals and globals after all to maintain this backwards compatibility. I also realised that it's a necessary evil: doing the converse (looking into locals first then globals would mean there is no way to point to the global A: it would always point to the local B.A.

What do you think?

[gvanrossum]

Okay. I still find this surprising but since it seems to be needed for the x: 'y' example, let's do it.

[bedevere-bot]

@gvanrossum: Please replace # with GH- in the commit message next time. Thanks!