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Incorrect missing-attribute when valid class attribute is included in __slots__ #2444

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Incorrect missing-attribute when valid class attribute is included in __slots__#2444
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yangdanny97
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googleissues from googletypecheckingv1-verifiedIn both V1 milestone and top-ranked (verified by ranking pipeline)
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@jakevdp

Description

@jakevdp
jakevdp
opened on Feb 16, 2026

Describe the Bug

Example:

class Foo:
    __slots__ = ["__name__"]

    def __init__(self):
        self.__name__ = "foo_instance"

print(Foo.__name__)

Runtime result:

$ python test.py
Foo

pyrefly check result:

$ pyrefly check test.py
ERROR Instance-only attribute `__name__` of class `Foo` is not visible on the class [missing-attribute]
 --> test.py:7:7
  |
8 | print(Foo.__name__)
  |       ^^^^^^^^^^^^
  |
 INFO 1 error

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