Code shared from the Rust Playground

playground-2.rs

// use std::cell::RefCell;
// Ownership: Copy semantic

// Copy trait should not have Drop trait implemented

#[derive(Debug, Clone, Copy)]
struct Parent(usize, Child, Child);

#[derive(Debug, Clone, Copy)]
struct Child(usize);

fn main() {
  let p1 = Parent(1, Child(11), Child(12));
  let p2 = p1;
  println!("a: p2:{:?}", p2);
  println!("a: p1:{:?}", p1);
}

playground-3.rs

// use std::cell::RefCell;
// Ownership: Lifecycle

#[derive(Debug)]
struct Parent(usize, Child, Child);

#[derive(Debug)]
struct Child(usize);

fn check_value(p: &Parent) {
println!("value {:?}", p)
}

fn change_value(p: &mut Parent) {
    p.0 = 100;
}

fn main() {
  let mut p1 = Parent(1, Child(11), Child(12));
  check_value(&p1);
  change_value(&mut p1);
  println!("a: p1:{:?}", p1);
}
// value Parent(1, Child(11), Child(12))
// a: p1:Parent(100, Child(11), Child(12))

playground.rs

// use std::cell::RefCell;
// Ownership: Move Semantic
use {
    std::ops::Drop
};

#[derive(Debug)]
struct Parent(usize, Child, Child);

#[derive(Debug)]
struct Child(usize);

impl Drop for Parent {
    fn drop(&mut self) {
        println!("Dropping {:?}", self);
    }
}

impl Drop for Child {
    fn drop(&mut self) {
        println!("Dropping {:?}", self);
    }
}



fn main() {
  //let mut rc1 = Rc::new(Child(1));
  let p1 = Parent(1, Child(11), Child(12));
  let p2 = p1;
  println!("a: p2:{:?}", p2);
  println!("a: p1:{:?}", p1);
//   |
//29 |   let p1 = Parent(1, Child(11), Child(12));
//   |       -- move occurs because `p1` has type `Parent`, which does not implement the `Copy` trait
//30 |   let p2 = p1;
//   |            -- value moved here
//31 |   println!("a: p2:{:?}", p2);
//32 |   println!("a: p1:{:?}", p1);
//   |                          ^^ value borrowed here after move
}