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Feature Request: support __slots__ #630
Description
Describe the Bug
When a class defines __slots__, pyrefly shouldn't allow writing to attributes that aren't specified in __slots__. This is tested in the dataclasses_slots conformance test, which we currently fail:
pyrefly/conformance/third_party/dataclasses_slots.py
Lines 24 to 25 in 47f5efe
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Activity
yangdanny97 commentedon Jul 4, 2025
I've been thinking about this and
__match_args__which has similar properties.I was thinking we should try and compute these while solving class metadata and store it as something better than
Type::Tuple([Type::Literal(...), Type::Literal(...)].Support `slots=True`
Adist319 commentedon Jan 6, 2026
I can take a look at this!
rchen152 commentedon Jan 7, 2026
Assigned, thank you!
Adist319 commentedon Jan 7, 2026
PR created here: #2029
migeed-z commentedon Feb 5, 2026
Thanks a lot! As we discussed, this PR still has some open questions regarding whether the errors it introduced are false positives or not and had not been active for sometime, unless @Adist319 would still like to look into the false positives, I can take it and/or open to the community
missing-attributewhen valid class attribute is included in__slots__#2444Enforce __slots__ validation for attribute writes (facebook#2695)
Add github workflow for v1 issue ranking
Enforce __slots__ validation for attribute writes (facebook#2695)
Enforce __slots__ validation for attribute writes (facebook#2695)
Add github workflow for v1 issue ranking