rust/tests/compile-fail/stacked_borrows/aliasing_mut2.rs

use std::mem;

pub fn safe(_x: &i32, _y: &mut i32) {} //~ ERROR barrier

fn main() {
    let mut x = 0;
    let xref = &mut x;
    let xraw: *mut i32 = unsafe { mem::transmute_copy(&xref) };
    let xshr = &*xref;
    // transmute fn ptr around so that we can avoid retagging
    let safe_raw: fn(x: *const i32, y: *mut i32) = unsafe {
        mem::transmute::<fn(&i32, &mut i32), _>(safe)
    };
    safe_raw(xshr, xraw);
}