<p>Does Rust have anything like a Java/ Objective-C "weak reference"? I.E. I mean</p><p>1. One Owner<br />2. Many Rc<T> type references, except<br />3. If the Owner ever Drops the true object, all Rc<T> type references become instantly aware of this, and the "weak" references can both be checked for liveness and also cleanly panic if they are accessed after the drop dead date</p>