trait T1 {
    fn f1(&self) -> i32;
}

trait T2 {
    fn f2(&self) -> f32;
}

struct S1 {
    id: i32,
}

struct S2 {
    iid: i32,
    fid: f32,
}

impl T1 for S1 {
    fn f1(&self) -> i32 { self.id }
}

impl T1 for S2 {
    fn f1(&self) -> i32 { self.iid }
}

impl T2 for S2 {
    fn f2(&self) -> f32 { self.fid }
}

// wish: fn test<T: T1 - T2>
fn test<T: T1>(val: T) {
    println!("test<T: T1> = {}", val.f1());
}

// wish: fn test<T: T1 + T2>
fn test2<T: T1 + T2>(val: T) {
    println!("test<T: T1 + T2> = {}, {}", val.f1(), val.f2());
}

fn main() {
    let s1 = S1 { id: 32 };
    let s2 = S2 { iid: 64, fid: 128.0 };

    test(s1);
    test2(s2); // wish: test(s2);
}