trait IA {
    fn f(&self);
    fn g(&self) {
        println!("IA::g")
    }
}

trait IB {
    fn f(&self);
    fn g(&self) {
        println!("IB::g")
    }
}

trait IC : IA {
    fn h(&self);
}

struct Q(i32);

impl IA for Q {
    fn f(&self) {
        println!("Q::IA::f | {}", self.0)
    }
}

impl IB for Q {
    fn f(&self) {
        println!("Q::IB::f | {}", self.0)
    }
}

impl IC for Q {
    fn h(&self) {
        println!("Q::IC::h | {}", self.0)
    }
}

fn test_ia(ia: &IA) {
    ia.f();
    ia.f();
    ia.f();
}

fn test_ic_ia(ia: &IC) {
    ia.f();
    ia.f();
    ia.f();
}

fn test_ic(ic: &IC) {
    ic.h();
    test_ic_ia(ic);
}

fn main() {
    let q = Q(7);
    test_ia(&q);
    println!();
    test_ic(&q);
    println!();
    println!("{}", std::mem::size_of::<Q>());
    println!("{}", std::mem::size_of::<&IA>());
    println!("{}", std::mem::size_of::<&IB>());
    println!("{}", std::mem::size_of::<&IC>());
}