alt Hacker NewsAre M and N supposed to be type parameters in your example? If so, then you don't need to store them in the struct. And once you remove that (and switch from dynamically sized vectors to statically sized arrays) your example becomes perfectly representable in Rust and C++ without dependent types
That's the "carry phantom types around" option, but it only gets you so far. If you never need to compute with the term, it's enough (see https://play.rust-lang.org/?version=stable&mode=debug&editio...).
You could use statically sized arrays, but if you can't have the static sizes of the arrays as your type parameters, but instead some arbitrary M and N, the size of your data structure isn't part of your type and you don't get the statically verified safety benefits. You also can't express M + N or anything of the sort.
Neither C++ nor Rust really hurt for expressivity, though.