Given that they know the list at compile time I wonder if they could do faster e.g. by using https://github.com/sfackler/rust-phf https://github.com/sfackler/ru

Given that they know the list at compile time I wonder if they could do faster e.g. by using https://github.com/sfackler/rust-phf https://github.com/sfackler/rust-phf to generate a perfect hash function over the set.