multiple inheritance. c++ : both sides can bring state. has diamond issues. Java : one side can bring state. other just signatures. too restrictive. What

multiple inheritance. c++ : both sides can bring state. has diamond issues. Java : one side can bring state. other just signatures. too restrictive. What you want is: both sides should be able to bring behaviour, but only side can bring state. (iirc, ruby does it like that... )