1 // A callee may not read the destination of our `&mut` without
2 // us noticing.
3
main()4 fn main() {
5 let mut x = 15;
6 let xraw = &mut x as *mut _;
7 let xref = unsafe { &mut *xraw }; // derived from raw, so using raw is still ok...
8 callee(xraw);
9 let _val = *xref; // ...but any use of raw will invalidate our ref.
10 //~^ ERROR: borrow stack
11 }
12
callee(xraw: *mut i32)13 fn callee(xraw: *mut i32) {
14 // We are a bit sneaky: We first create a shared ref, exploiting the reborrowing rules,
15 // and then we read through that.
16 let shr = unsafe { &*xraw };
17 let _val = *shr;
18 }
19