#![allow(unused_variables)]
use std::ops::Add;

#[derive(Debug)]
struct A(i32);

#[derive(Debug)]
enum E{ONE,TWO,THREE}

impl Add for A {
    type Output = A;

    fn add(self, rhs: A) -> A {
        A(self.0 + rhs.0)
    }
}

fn from_value<T: core::fmt::Debug>(t: T){
    dbg!(t);
}

fn from_ref<T: core::fmt::Debug>(t: &T){
    dbg!(t);
}

fn from_mut<T: core::fmt::Debug + std::ops::Add::<Output=T>>(t: &mut T){
    dbg!(t);
    t = &mut *t + *t;
}

fn main() {
    let mut a = A(1);
    let mut b = E::ONE;
    from_ref(&a);
    from_mut(&mut a);
    let mut c = 1 + a.0;
    from_value(a);

    //from_ref(&b);
    //from_mut(&mut b);
    //from_value(b);

    from_ref(&c);
    from_mut(&mut c);
    from_value(c);
}