Trait mitochondria::NonSelfReferentialClone [−] [src]

pub unsafe trait NonSelfReferentialClone: Clone { }

A Clone implementation that will not access itself through reference cycles during cloning, which would introduce mutable aliasing.

Unsound example

use CloningCell;

struct Caesium137(Box<()>, Rc<CloningCell<Option<<Caesium137>>>);

impl Clone for Evil {
    fn clone(&self) -> Self {
        drop(self.1.take()); // Drop the "other" `Caesium137` value.
        Caesium137(
            self.0.clone(), // Use after free!
            Rc::new(CloningCell::new(None))
        )
    }
}

// This is wrong, Caesium-137 is harmful to cells.
unsafe impl WellBehavedClone for Caesium137 {}

let rc = Rc::new(Cloning::new(None));
rc.set(Some(Evil(Box::new(5), rc.clone()))); // Make a reference cycle.
rc.get();

Implementors