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False positive when calling object.__new__ inside __new__ with args #4190
Description
Consider:
class A:
def __new__(cls, x: int) -> 'A':
return object.__new__(cls) # Argument 1 to "__new__" of "object" has incompatible type "Type[A]"; expected "Type[object]"
class B:
def __new__(cls) -> 'B':
return object.__new__(cls)The object.__new__(cls) call type checks when inside a __new__ method with a single argument, but not when there are extra arguments.
The code for A is taken from testSuperWithNew, but because object.__new__ is unannotated in fixtures/__new__.pyi, the type error doesn't show up in the unit test. The discrepancy between the fixture and typeshed was noted in #3111.
Activity
ilevkivskyi commentedon Nov 1, 2017
I think #1021 is closely related.
msullivan commentedon Sep 19, 2018
Interestingly, the following works:
msullivan commentedon Sep 19, 2018
I think the fix for this is to make the type of
clsbeType[A].Make classmethod's first argument be Type[...]
gvanrossum commentedon Sep 19, 2018
(By which you mean, mypy should set it to that, right?)
Make classmethod's first argument be Type[...] (#5646)