The borrow checker is what makes unique pointers in Rust unique.  In C++, you can pass ownership but still reference the unique pointer you moved from. It should crash at run time, deferencing null, but the compiler will happily compile it.<p>Can you actually cause #11 in Rust?  Example?<p>Circular references remain a problem, but they can only cause memory leaks, not security errors or crashes.  It would be nice to have a Rust static analysis tool for circular references.  Often, you can prove their absence for a type.