Attribute narrowing with optional value

[maggiemoss]

Describe the Bug

def question() -> bool:
    return True

class A:
    arg: int | None 

inst = A()
# abs is load bearing
inst.arg = abs(int(0))

if question():
    # see bytecode size comment in the absolute jump case above
    inst.arg += 2

Sandbox Link

https://pyrefly.org/sandbox/?code=CYUwZgBAjgriDOAXAlgewHYAoCUEC0AfBAEaqoA2AXAFAR0QBOIiMD6EAKg3NbwMbkAhvHgQAgjXoRBDAOaUIydIggAfCADkMICLyVIIAXnE5qAYmnFRyUeVSDgJEDKWzq%2BxADoZso5fiYSoiYAAzY2HqQsAgoGDiS9BbwIDrEAJ6IIHyooBDwyABeOtkAtiUgyorsiAAWOoJWFDCZEABWMCUADhB8wvWkAG4gtPQe3nIQANTGAExAA&version=3.12

(Only applicable for extension issues) IDE Information

No response

[yangdanny97]

This is because we don't narrow attributes on assignment. Whether we should do it or not, I'm not sure.

[asukaminato0721]

this is fixed.

[asukaminato0721]

#claim

[github-actions]

@asukaminato0721 you've claimed this issue — it's now assigned to you. Thanks for picking it up! 🎉