On a different note it would be interesting to see the Ruby and Rust methods side to side. Ruby is fairly readable in general. And while Rust is a big improvement over C++ regarding to many things, readability is usually not one of them...
I have seen a bit of production ruby and would say the reverse. Especially the augmentation of types gets confusing fast. With rust at least you have to own a trait or the type to implement it and you have to import the trait to use methods.
