Make return type implicitly None for type checked __init__ and __init_subclass__ #5677
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| @@ -407,6 +406,10 @@ def _visit_func_def(self, defn: FuncDef) -> None: | |||
| add_symbol = False | |||
| if add_symbol: | |||
| self.type.names[defn.name()] = SymbolTableNode(MDEF, defn) | |||
| if defn.type is not None and defn.name() in ('__init__', '__init_subclass__'): | |||
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Are you sure this works with overloads and decorated methods? Please add tests to verify that.
Also perhaps it should only work inside a class definition?
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I think one needs similar check at least in visit_overloaded_func_def.
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@gvanrossum It works only inside a class definition.
@gvanrossum @ilevkivskyi You are right, I will find a way to extend behavior.
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Can you also add a test for overloading? |
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I'm on it, but I can say that this change works with overloading too. |
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@gvanrossum It may be good to add tests for explicit |
Yes, please. |
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I think this PR is ready to merge. |
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Sorry, I got busy with other stuff. Will review later today.
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Done (sorry for the delay). Thanks for fixing this long-standing issue! |
…_subclass__ (python#5677) Implements python#604 (comment).
This is the implication of #5677 where the return type of `__init__` is inferred given that at least one argument is typed. However, if no argument is present in `__init__`, `-> None` becomes compulsory if we are to enable type-checking on that method without using `--check-untyped-defs` flag. I believe it is worth mentioning in the section of "No errors reported for obviously wrong code".
They are noisy and not needed in mypy any more (python/mypy#5677).
This has to be done, because ubuntus mypy is too old (still v0.560). See also python/mypy#5677.
Implements #604 (comment).