Where are you getting this from? None of those features have a performance cost, if used according to some simple guidelines. In fact, multiple dispatch is ess

Where are you getting this from? None of those features have a performance cost, if used according to some simple guidelines. In fact, multiple dispatch is essential to get good performance, abstract types have a cost if explicitly used inside struct definitions, but that's why you use parametric types, and abstract types do not have a cost in function signatures. Macros are expanded at compile-time, and at least have no runtime cost, in fact they are often used for improved performance. I think there's some fundamental misunderstanding going on here, but I'm not sure what it is. Or do you mean to say that if it is possible to write slow code in a language, then only a subset of that language has good performance? If that is the case, I don't know how to respond.