python / python/mypy

Safe handling of `Self` typed attributes w.r.t. overrides.

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feature topic-self-types
Dominant language
Python
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Description

This is a follow up for https://github.com/python/mypy/pull/14041

This example doesn't give an error, while it probably should:

from typing import Self

class C:
    x: Self

class D(C):
    x: D  # Note this is already unsafe, but it essentially same as #2353 (for methods)

class E(D):
    pass  # This creates conflicting types for `x` from `C` and from `D`.

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Research direction

Review the follow-up context in PR #14041 and reproduce the provided C, D, and E example with mypy. Trace the existing override handling for Self-typed attributes and add coverage for the conflicting inherited types; done means mypy reports the expected error for E.

Written by the indexing model from the issue text.

Assessment

Tech stack
python
Domain
devtools
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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