Well, you could just assume that all non-Scala code is impure. Actually, thinking about it, why not just make it illegal to modify arguments, full stop? It's p

Well, you could just assume that all non-Scala code is impure. Actually, thinking about it, why not just make it illegal to modify arguments, full stop? It's perhaps the worst software practice I can think of. I think Oracle is going to wait a long time until they add that to Java, and it's not going into the JVM before it's going into Java, unfortunately. Well, there is a limited number of instructions in the JVM, so using them on things that are unproven might be a very bad idea.