objc-missing-hash¶
Finds Objective-C implementations that implement -isEqual: without also
appropriately implementing -hash.
Apple documentation highlights that objects that are equal must have the same hash value: https://developer.apple.com/documentation/objectivec/1418956-nsobject/1418795-isequal?language=objc
Note that the check only verifies the presence of -hash in scenarios where
its omission could result in unexpected behavior. The verification of the
implementation of -hash is the responsibility of the developer, e.g.,
through the addition of unit tests to verify the implementation.