Rust also allows polymorphic return types.

    trait Bounded {
        fn min_bound() -> Self;
        fn max_bound() -> Self;
    }

Which can be used like so. Using type inference.

    fn add_min_to_set<T:Bounded, S:MutableSet<T>>(set: &mut S) {
        set.insert(Bounded::min_bound())
    }
 

Or you can be more explicit

    let mut i: u8 = Bounded::min_bound();
    while i < Bounded::max_bound() { println!("{}", i); i += 1; }

Edit: spacing, s/++/+= 1/