All of what your saying doesn't actually contradict what I wrote. The metadata for generics is not used by the VM during execution. It only exists so that you c

All of what your saying doesn't actually contradict what I wrote. The metadata for generics is not used by the VM during execution. It only exists so that you can compile against .class files as if they were source. IMHO it was still a major design mistake that has cost everyone else more time in the end. A classic near-term/long-term miscalculation. For a counterpoint, C# introduced generics and rewrote the class library. They're in the bytecode, not just metadata. The VM dynamically specializes JIT code as necessary, and shares equivalent specializations to avoid code explosion. > Also, truly reified generics is really hard. I think this statement is false. It's not intrinsically hard; it's only hard because of a lot of other constraints. For example, Virgil has "reified"[1] generics since 2.0 and I just use monomorphization. MLton did the same, 20 years back. Code explosion isn't that bad for medium-sized programs. [1] "reified" implies there is a runtime representation, which is not really what's going on. With static specialization, it's possible to completely compile away any additional metadata representation, as it either becomes implicitly part of a function specialization or the class metadata for specialized classes. The only real reason I see to not use monomorphization is if you have polymorphic recursion, or first-class polymorphism. Virgil doesn't allow either of those.