#![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); } //~ ERROR accessing memory with alignment 1, but alignment 2 is required }