Actually, there's a very elegant solution to the diamond problem. Eiffel does this with a renaming mechanism. Martin Odersky certainly knew about Eiffel's solut

Actually, there's a very elegant solution to the diamond problem. Eiffel does this with a renaming mechanism. Martin Odersky certainly knew about Eiffel's solution when he designed Scala, but my guess is that, he chose the simpler solution of traits, just like most languages, because general multiple inheritance just isn't too useful. Still, it's a shame that most people interested in programming languages have never heard about Eiffel, or ever read the superb book "Object-Oriented Software Construction" by Eiffel's creator, Bertrand Meyer. Eiffel has many flaws (the most proeminent being the complete lack of support for functional idioms), but it has very good ideas as well. (Perhaps the most popular influence Eiffel had on other languages is Design by Contract and the uniform access principle, which you see in most "modern" languages.)