use std::sync::Arc;
use std::ops::Deref;

struct Foo {
    val: usize,
}

#[derive(Clone)]
struct ArcFoo {
    inner: Arc<Foo>,
}

impl Deref for ArcFoo {
    type Target = Foo;

    #[inline]
    fn deref(&self) -> &Foo {
        &self.inner
    }
}

impl ArcFoo {
    fn new(f: Foo) -> ArcFoo {
        ArcFoo {
            inner: Arc::new(f),
        }
    }

    fn custom_function(&self) {
        println!("custom function for Arc<Foo>: {}", self.inner.val)
    }
}

fn main() {
    let custom_arc = ArcFoo::new(Foo{val: 3});
    println!("hello world {}", custom_arc.val);
    custom_arc.custom_function();
}