F811 incorrectly raised for type annotation of imported variable

[mick88]

The following piece of code raises F811 error in pyflakes 2.3.0:

        from django.core.files.storage import default_storage
        default_storage: Storage
        file_path = os.path.join(constants.FILE_FIELD_UPLOAD_DIR_NAME, value.name)
        value = default_storage.save(file_path, value)

I am using pyflakes with flake8 and getting this output:

F811 redefinition of unused 'default_storage' from line 124
        default_storage: Storage
        ^
1     F811 redefinition of unused 'default_storage' from line 124

the code works correctly and default_storage: Storage does not redefine the variable, and default_storage is used two lines below.

[asottile]

can confirm -- looks like a slight regression in #535 (which introduces annotated-assignments without values as types-only bindings) -- probably need to special case this particular situation of an annotation-only assignment of an imported name

[henzef]

I think I have another example for this:

gvar: int

def set_var():
    global gvar
    gvar = 1

def print_var():
    print(gvar)

set_var()
print_var()

reports "F821 undefined name 'gvar'", which seems to be the same bug. Or should I open a separate issue?

[asottile]

@henzef that's unrelated and covered in #621