Bind self-types in checkmember for decorated classmethods #19025
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Diff from mypy_primer, showing the effect of this PR on open source code: steam.py (https://github.com/Gobot1234/steam.py)
+ steam/enums.py:322: error: Incompatible return value type (got "int", expected "Self") [return-value]
- steam/state.py:2439: error: Argument 2 to "__get__" of "classproperty" has incompatible type "type[Awardable[int]]"; expected "type[Self]" [arg-type]
+ steam/state.py:2439: error: Argument 2 to "__get__" of "classproperty" has incompatible type "type[Awardable[int]]"; expected "type[type[Awardable[int]]]" [arg-type]
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Okay, the |
| t, isuper, is_classmethod, is_staticmethod, mx.self_type, original_vars=original_vars | ||
| ) | ||
| if is_decorated and not is_staticmethod: | ||
| t = expand_self_type_if_needed( |
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I don't quite understand why we need to put this self type expansion here. Specifically: this branch is only for decorators. Shouldn't whatever is applying the decorators handle self types instead?
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This function handles lookup on classes, we bind self types here for everything that can reasonably contain them as this is the latest moment possible (see Var branch above). Consider a decorator that preserves function signature applied to a def method(self) -> Self. Applying the decorator still yields a Self-returning callable, which is the best representation until we actually want to show it or apply it to something, when Self loses its semantic meaning. Otherwise, for example, that method will be impossible to cleanly override in subclasses.
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Alright that makes sense then. I didn't realize when this function was called. (fyi I'm unable to resolve things, so you'll have to.)
| t, isuper, is_classmethod, is_staticmethod, mx.self_type, original_vars=original_vars | ||
| ) | ||
| if is_decorated and not is_staticmethod: | ||
| t = expand_self_type_if_needed( |
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Alright that makes sense then. I didn't realize when this function was called. (fyi I'm unable to resolve things, so you'll have to.)
Fixes #19023. Fixes #18993.