Shared via Rust Playground

playground.rs

trait Associated<T> {
    fn associated(&self) -> T;
}

trait Thing : Associated<&'static str> {
    fn whatever(&self);
}

macro_rules! associated {
    ($t:ident, $val:expr => $typ:ty) => {
        impl $crate::Associated<$typ> for $t {
            fn associated(&self) -> $typ {
                $val
            }
        }
    }
}






struct Stuff;

impl Thing for Stuff {
    fn whatever(&self) {}
}
associated!(Stuff, "data" => &'static str);

struct Muff;

impl Thing for Muff {
    fn whatever(&self) {}
}
associated!(Muff, "mata" => &'static str);

fn main() {
    println!("{}", Stuff.associated());
    println!("{}", Muff.associated());
}