Delayed attribute assignment to object() may cause incorrect inference of instance attributes

[nelfin]

@cdce8p: aiohttp and VLCTelnet turned out to be red herrings. This case fails on current stable versions:

class Example:
    def prev(self):
        pass
    def next(self):
        pass
    def other(self):
        pass


ex = Example()
ex.other()  # no warning
ex.prev()   # no warning
ex.next()   # no warning

import typing

ex.other()  # no warning
ex.prev()   # false-positive: not-callable
ex.next()   # false-positive: not-callable

Originally posted by @nelfin in #927 (comment)

I've bisected this down to 78d5537. Pylint 2.3.1 passes this case with 20a7ae5 and fails with 78d5537

[nelfin]

Minimal case:

class Example:
    def func(self):
        pass


whatthe = object()
whatthe.func = None

ex = Example()
ex.func()   # false-positive: not-callable

[nelfin]

Not caused by 78d5537, just revealed by it. typing imported collections, collections.OrderedDict had an ambiguously inferred case that was previously broken by failure with positional-only arguments which was fixed in 78d5537.