main()1 fn main() {
2 let target = Box::new(42); // has an implicit raw
3 let xref = &*target;
4 {
5 let x : *mut u32 = xref as *const _ as *mut _;
6 unsafe { *x = 42; } // invalidates shared ref, activates raw
7 }
8 let _x = *xref; //~ ERROR borrow stack
9 }
10