#![allow(unused_variables)]
#![feature(allocator_api)]
fn main() {
    fn _inner() -> core::result::Result<(), impl core::fmt::Debug> {
        use std::alloc::System;
        let mut values = Box::<[u32], _>::try_new_uninit_slice_in(3, System)?;
        values[0].write(1);
        values[1].write(2);
        values[2].write(3);
        let values = unsafe { values.assume_init() };
        assert_eq!(* values, [1, 2, 3]);
        Ok::<(), std::alloc::AllocError>(())
    }
    _inner().unwrap()
}