mypy does not recognize __qualname__

[jtmoon79]

1. Given Python file test1.py

class A(object):
    NAME = __qualname__

2. run mypy checking

   mypy test1.py
   

3. BUG: mypy reports not defined

   test1.py:2: error: Name '__qualname__' is not defined
   

The Python interpreter runs the code without error.

__qualname__ has been available since Python 3.3.

Tested on Python 3.7.1, using mpypy 0.670.

[ilevkivskyi]

Such kind of issues are typically easy to fix. You can look at how implicit_module_attrs() are implemented, and do the same for classes. Note however that we are currently migrating to a new semantic analyzer, so the fix should apply to both.

[jtmoon79]

Thanks @ilevkivskyi . I'm curious, why was this Issue labeled "false-positive"?

[gvanrossum]

The label "false-positive" refers to the fact that mypy gives an error where it shouldn't. It doesn't mean there's anything wrong with your bug report!

[aaalex5]

If no one is working on this issue, I'd like to give it a shot if possible. :)

[ilevkivskyi]

Go ahead! But please be aware that we are currently working on big refactoring on semantic analyzer, so you will need to copy your fix to the newsemanal as well.

[aaalex5]

So I believe I fixed the issue within the normal mypy directory, but I'm not sure where in newsemanal it would be necessary to make a change? The only place I can think to make additions or changes would be in newsemanal/semanal_pass1.py, otherwise it doesn't look like there would be a change needed other than the one in mypy/mypy/nodes.py where implicit_module_attrs() is

[ilevkivskyi]

I don't think using/changing implicit_module_attrs is the best solution. __qualname__ is only defined at class scope, at module scope it is a NameError. Probably we should have something like implicit_class_attrs.

[aaalex5]

Any tips on implementing that? implicit_module_attrs uses a set with 'module name attributes' keys and 'type' values so for an implicit_class_attrs would there be even be a 'type'? I'm just wondering if a set would even be the correct solution. Also, what other classes, if any, would you recommend I add?

[forrestchang]

@aaalex5 I started a pull request #7683.

[asottile]

#10570 is a duplicate with slightly more details