#![allow(unused_variables)]
#![feature(allocator_api)]
#![feature(get_mut_unchecked)]
fn main() {
    fn _inner() -> core::result::Result<(), impl core::fmt::Debug> {
        use std::sync::Arc;
        use std::alloc::System;
        let mut five = Arc::<u32, _>::try_new_uninit_in(System)?;
        let five = unsafe {
            Arc::get_mut_unchecked(&mut five).as_mut_ptr().write(5);
            five.assume_init()
        };
        assert_eq!(* five, 5);
        Ok::<(), std::alloc::AllocError>(())
    }
    _inner().unwrap()
}