A example of two object own each other.

own_mut_each_other.rs

use std::rc::Rc;
use std::cell::RefCell;

struct Foo {
    // Owns multiple mut trait objects
    bars: Vec<Rc<RefCell<Bar>>>,
}

impl Foo {
    fn new() -> Foo {
        Foo { bars: vec![] }
    }

    fn add_bar(&mut self, bar: Rc<RefCell<Bar>>) {
        self.bars.push(bar);
    }
}

trait Bar {
    fn add_foo(self, foo: Rc<RefCell<Foo>>);
}


struct Baz {
    foo: Option<Rc<RefCell<Foo>>>,
}

impl Baz {
    fn new() -> Baz {
        Baz { foo: None }
    }
}

impl Bar for Baz {
    fn add_foo(self, foo: Rc<RefCell<Foo>>) {
        let baz = Rc::new(RefCell::new(self));
        foo.borrow_mut().add_bar(baz.clone());
        baz.borrow_mut().foo = Some(foo);
    }
}


fn main() {
    let baz = Baz::new();
    let foo = Foo::new();
    baz.add_foo(Rc::new(RefCell::new(foo)));
}