#![allow(unused_variables)]
#![feature(allocator_api)]
fn main() {
    use std::sync::Arc;
    use std::alloc::System;
    let five = Arc::new_in(5, System);
    unsafe {
        let (ptr, _alloc) = Arc::into_raw_with_allocator(five);
        Arc::increment_strong_count_in(ptr, System);
        let five = Arc::from_raw_in(ptr, System);
        assert_eq!(2, Arc::strong_count(& five));
        Arc::decrement_strong_count_in(ptr, System);
    }
}