Antoni Boucher has started a new UEFI-centric Rust-language project on Github, called UEFI_Rust, “Boot to Rust from UEFI”:
https://github.com/antoyo/uefi_rust
So far it mainly consists of a single small source file, at this point it is basically a Rust-based hello-world for UEFI environment.
https://raw.githubusercontent.com/antoyo/uefi_rust/master/src/lib.rs