Rust generics are not intended as a one-to-one replacement for C++ templates. Most complex cases of template-level programming would be addressed with macros (possibly proc macros) in Rust.

Const generic expressions are still being worked. They are what is blocking portable simd. They are also a much cleaner way to implement things like matrix operations or really anything where a function with two or more arguments of one or more types returns things that have types that are a combination or modification of the input types.