use std::ops::{Deref, DerefMut};
struct DummyContainer(i32);

struct Proxy<'a>(&'a mut DummyContainer, i32);

impl DummyContainer {
    fn get_mut(&mut self) -> Proxy {
        Proxy(self, 0)
    }
}

impl<'a> Drop for Proxy<'a> {
    fn drop(&mut self) {
        (*self.0).0 = self.1
    }
}

impl<'a> Deref for Proxy<'a> {
    type Target = i32;
    fn deref(&self) -> &Self::Target {
        &self.1
    }
}


impl<'a> DerefMut for Proxy<'a> {
    fn deref_mut(&mut self) -> &mut Self::Target {
        &mut self.1
    }
}


pub fn main() {
    let mut c = DummyContainer(0);
    let mut ptr = c.get_mut();
    *ptr = 3;
    std::mem::drop(ptr);
    println!("{}", c.0);
}