Overriding an overloaded method that returns a value of a Union type #10799
Labels
bug
mypy got something wrong
topic-inheritance
Inheritance and incompatible overrides
topic-overloads
Comments
|
I think this is expected behavior. Overloads are not inherited and must be replicated in the subclass. See #10699. |
|
Thank you for giving the relevant information. I'll follow the issue and the discussion cited in it. In the meantime, there is still an issue as I wrote in the third item of the "additional observations" above. To be specific, here is an example: class Base:
@staticmethod
@overload
def A(x: str) -> str:
...
@staticmethod
@overload
def A(x: int) -> int:
...
@staticmethod
def A(x: Any) -> Union[str, int]:
return x
class Derived(Base):
@staticmethod
@overload
def A(x: str) -> str:
...
@staticmethod
@overload
def A(x: int) -> int:
...
@staticmethod
def A(x: Any) -> Union[str, int]: # Error here!
return xIn fact, this is the original case I faced with. Is this expected as well? |
|
No, that's not expected. It looks like a bug. Appears to be a bad interaction between |
|
The above bug appears to have been fixed. It no longer occurs with the latest version of mypy (1.5). |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Bug Report
Mypy raises an error when overriding an overloaded method that returns a value of a Union type, even though the original and overridden methods have the same signature.
To Reproduce
Expected Behavior
Because the implementations of
Base.AandDerived.Ahave exactly the same signature indeed, I want this to pass the type checking.Actual Behavior
An error
Signature of "A" incompatible with supertype "Base"is raised at the definition ofDerived.A.Some additional observations are:
Base.AandDerived.Aare implemented as static methods, adding @overload-decorated methods to the subclass does not resolve the errorYour Environment
The text was updated successfully, but these errors were encountered: