Comment by notatallshaw
13 hours ago
I assume in your example if you update the foo declaration to the following it solves the complaint:
foo: list[str] = []
If so this a type checking design choice:
* What can I infer from an empty collection declaration?
* What do I allow further down the code to update inferences further up the code?
I don't know Pyrefly's philosophy here, but I assume it's guided by opinionated coding guidelines inside Meta, not what is perhaps the easiest for users to understand.
Yes, annotating the type explicitly fixes it; but tbh I'd consider that type annotation "unnecessary/distracting code litter".
As far as their philosophy goes, it's an open issue they're working on, so their philosophy seems to agree this particular pattern should work :)
I agree, but as a type checker it is a subjective choice, whether to be explicit and not make assumptions or whether to infer from certain certain patterns as probably correct and not be noisy to the user. Very glad to see they plan to fix this.