Private and protected members in classes

Private and protected members in classes

Private and protected members in a class affect their compatibility. When an instance of a class is checked for compatibility, if the instance contains a private member, then the target type must also contain a private member that originated from the same class. Likewise, the same applies for an instance with a protected member. This allows a class to be assignment compatible with its super class, but not with classes from a different inheritance hierarchy which otherwise have the same shape.