Self-referencing structs

internals ideas (deprecated)
3

As far as I can tell, the only way to do this safely is with Rc and friends.

struct MyStruct {
   x: Rc<int>,
   storage: Vec<Rc<int>>
}

If you want to get mutable references to the data you will have to use an abstraction like RefCell, which will check that you are not violating Rust’s invariants dynamically:

struct MyStruct {
    x: Rc<RefCell<int>>,
    storage: Vec<Rc<RefCell<int>>>
}

The proposed 'self lifetime for contained pointers only upholds one aspect of Rust’s rules: & and &mut references cannot be NULL. However, it does not allow for upholding the other invariants relating to borrowing and mutability.

If you need a struct which actually has to refer to itself (not into itself) then you can do something similar:

struct MyStruct {
   val: int
   self: Option<Rc<RefCell<MyStruct>>>
}

impl MyStruct {
    fn new(val: int) -> Rc<RefCell<MyStruct>> {
        let mut this = Rc::new(RefCell::new(MyStruct { val: val, self: None }));
        this.borrow_mut().self = Some(self.clone());
        this
    }
}