That's one place where C++ still has Rust beat. The C++'s templates are (for better or for worse), far more powerful and expressive than Rust's parametric polym

That's one place where C++ still has Rust beat. The C++'s templates are (for better or for worse), far more powerful and expressive than Rust's parametric polymorphism. There have been advances in doing more extreme compile time metaprogramming using Rust's generics, including unit systems and n-dimensional arrays, but we are still hanging out for things like parametrising types over integers, and for the stabilisation of const functions that will make this kind of thing easier to do. As for something akin to expression templates... I'm not sure if that is on the horizon yet, or even if it is desired. This kind of thing takes time, and won't happen any time soon, as far as I know.