// run-pass #![feature(ptr_internals, test)] extern crate test; use test::black_box as b; // prevent promotion of the argument and const-propagation of the result use std::ptr::Unique; const PTR: *mut u32 = Unique::dangling().as_ptr(); pub fn main() { // Be super-extra paranoid and cast the fn items to fn pointers before blackboxing them. assert_eq!(PTR, b::<fn() -> _>(Unique::<u32>::dangling)().as_ptr()); }