#![allow(dead_code, deprecated, unused_variables, unused_mut)]
#![feature(unsafe_cell_access)]
use std::cell::UnsafeCell;
fn main() {
    let uc = UnsafeCell::new(5);
    unsafe {
        *uc.as_mut_unchecked() += 1;
    }
    assert_eq!(uc.into_inner(), 6);
}