rust/tests/compile-fail/intrinsics/copy_unaligned.rs

//error-pattern: accessing memory with alignment 1, but alignment 2 is required
#![feature(intrinsics)]

// Directly call intrinsic to avoid debug assertions in libstd
extern "rust-intrinsic" {
    fn copy_nonoverlapping<T>(src: *const T, dst: *mut T, count: usize);
}

fn main() {
    let mut data = [0u16; 8];
    let ptr = (&mut data[0] as *mut u16 as *mut u8).wrapping_add(1) as *mut u16;
    // Even copying 0 elements to something unaligned should error
    unsafe { copy_nonoverlapping(&data[5], ptr, 0); }
}