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The type checker only seems satisfied if I annotate the return type of t() to be Optional[Dict] , but this method can never return None , so I don't think it should be optional.

If I change the initial value of self.bla in __init__() to {} it still things the return value is None . Same error if I use a str instead of a dict

With the following -> Dict or None annotation pycharm (2019.2) does not complain and I get dict type autocompletion for fdictnoneres :

def fdictnone() -> Dict or None:
    return dict(a=1, b=2)
fdictnoneres = fdictnone()
When using TypeVar pycharm does not provide dict type autocompletion for tfunres:
from typing import TypeVar
T = TypeVar('T', dict, None)
def tfun() -> T:
    return dict(a=1, b=2)
tfunres = tfun()
                I'm not sure why None is treated differently when a variable can have None value until proper value gets assigned to it.
– Ganesh Satpute
                Jul 13, 2020 at 14:53
                PyCharm 2020.3.2 does not autocomplete "List or None" for me :( Screenshot - i.ibb.co/wRqbZnc/2021-02-04-17-01-38.png
– Dmitriy Vinokurov
                Feb 4, 2021 at 12:04
This way, the variables are recognised separately. Note however, that this solution is stupid -- you're just doing a workaround for what I would consider a bug in PyCharm! In fact, I have the same problem and still no solution...
For now I would suggest either ignoring the warning or forcing PyCharm to ignore it by adding:
# noinspection PyTypeChecker
I have read somewhere, that the type hinting is not fully implemented yet in PyCharm, so that might still come... I don't remember where I read this though, so no guarantee!
I found Type hinting the instance variable works.   I also don't seem to incur the original inspection error in the 2018 pro version of pycharm, so I'm wondering if they've updated the inspection to be a little smarter. 
class T(object):
    def __init__(self):
        self.bla:Dict = None
    def t(self) -> Dict:
        if self.bla is None:
            self.bla = {'foo' : 'bar'}
        return self.bla
                self.bla: Dict = None gives me Expected type 'dict', got 'None' instead in PyCharm 2021.2.1 (Community Edition). :(
– BubbleMaster
                Sep 2, 2021 at 14:44
I'm pretty sure it's because it is initialized as None on your constructor.
I believe if you explicitly state the type in the class definition it should work. Eg:
class T:
    bla: Dict
    def __init__(self):
        self.bla = None
        
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