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Add support for classmethod property from python3.9 #11619
Description
class Foo:
@classmethod
@property
def bar(cls) -> str:
return cls.__name__
def foo_bar(msg: str) -> None:
print(msg)
foo_bar(Foo.bar)mypy --python-version 3.9 test.py
test.py:11: error: Argument 1 to "foo_bar" has incompatible type "Callable[[], str]"; expected "str"
Found 1 error in 1 file (checked 1 source file)
As stated in https://docs.python.org/3.9/library/functions.html#classmethod this new classmethod property is completely valid so mypy shouldn't report an error.
Activity
AlexWaygood commentedon Nov 25, 2021
It might be worth noting that there are currently active discussions on whether to deprecate the ability to stack
@classmethodon top of@property, as it's responsible for a lot of bugs in cpythonAlexWaygood commentedon May 29, 2022
To update: this behaviour has now been deprecated in 3.11 (python/cpython#92379)
headtr1ck commentedon Sep 29, 2022
This has been deprecated in python 3.11 it is still correct syntax in python <3.11.
However, it is still semantically incorrent and mypy is right in complaining (the property decorator is not returning what you think it returns).
Maybe one could simply improve the error message for this case?
Remove abstract class property
karlicoss commentedon Mar 20, 2023
Would it be possible to change the error category from
miscto something more specific? Then it would be easy to suppress it on older python versionshauntsaninja commentedon Apr 27, 2023
This behaviour has been deprecated in CPython, so mypy will not be adding support for it.
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