[microtonal]

Your suggestions make sense, but I can't help but think that there is something fundamentally weird about basically having to use generic programming just to take a string arg.

Indeed, it's the hard trade-off to make every time need a string reference, do you want a function that is slightly more general or one that has an easy-to-read signature?

It becomes even more interesting when defining trait methods. E.g.:

    trait Hello {
      fn hello<S>(who: S) where S: AsRef<str>;
    }

Has the benefit of being more general, but cannot be used as a trait object (dynamic dispatch), since it wouldn't be possible to generate a vtable for &Hello.

I generally prefer the generic approach for functions/methods that want to own a String, since using some_str.to_owned() to pass something to a method is not very ergonomic (relative compared to &owned_string for a function that takes &str). But you have to be certain that you don't want to use the trait as a trait object.