Rust is a relatively new programming language.
Back in 2013, Eric Holk started adding UEFI support in Rust:
Starting last month, there’s another Rust UEFI library, by William Kunkel:
I don’t know how to program in Rust yet, so I can’t say how usable Rust is with UEFI yet. The last library looks promising, perhaps more general-purpose than the previous projects, as far as I can tell. I guess I am going to have to learn Rust…