Only return a declared type from __new__ if it is a subtype of the class #7656
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ilevkivskyi
approved these changes
Oct 9, 2019
| @@ -6031,7 +6031,7 @@ class A: | |||
| def __new__(cls) -> int: # E: Incompatible return type for "__new__" (returns "int", but must return a subtype of "A") | |||
| pass | |||
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| reveal_type(A()) # N: Revealed type is 'builtins.int' | |||
| reveal_type(A()) # N: Revealed type is '__main__.A' | |||
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I think we should keep the declared return type for the class itself. The original PR closed an issue called "Honor return type of __new__", so this change would be a step back.
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We report an error at the __new__ declaration site, and there are a bunch of other situations where we wouldn't honor it before (like if it is a union or something other than an instance or tuple), so I think this actually makes thing a little more consistent.
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thanks! it worked however i found another problem with popen inheritance, i am posting an issue right now |
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Fixes #7597.