from __future__ import annotations as <identifier> not supported

[analog-cbarber]

In pylint 2.6.0 (and earlier) under python 3.7, the following produces an incorrect warning for
the '-> C:' return value.

from __future__ import annotations as __annotations__

class C:
    @classmethod
    def create(cls) -> C: # bogus warning: Undefined variable 'C'
        return cls()

There is no warning when the as clause is not there.

This clause is required in some spaces in order to avoid having the annotations symbol pollute the
namespace and is not supposed to affect the processing future clause.

See https://docs.python.org/3/reference/simple_stmts.html#future

[analog-cbarber]

The problem appears to be here:
https://github.com/PyCQA/pylint/blob/5071831a5feb608fae1a4891ccec776860d3cce4/pylint/checkers/utils.py#L1266-L1275

This check is incorrect. I think that instead it should be checking the future_imports attribute
of the astroid Module object. I think this might work:

def is_postponed_evaluation_enabled(node: astroid.node_classes.NodeNG) -> bool: 
     """Check if the postponed evaluation of annotations is enabled""" 
     module = node.root()
     return "annotations" in module.future_imports

[AWhetter]

I can reproduce this on master with Python 3.8 as well. Your proposed correction looks like the right fix to me too.