//@ run-pass //@ compile-flags: -C debug-assertions #![feature(strict_provenance, pointer_is_aligned)] #[repr(packed)] struct Misaligner { _head: u8, tail: u64, } fn main() { let memory = [Misaligner { _head: 0, tail: 0}, Misaligner { _head: 0, tail: 0}]; // Test that we can use addr_of! to get the address of a packed member which according to its // type is not aligned, but because it is a projection from a packed type is a valid place. let ptr0 = std::ptr::addr_of!(memory[0].tail); let ptr1 = std::ptr::addr_of!(memory[0].tail); // Even if ptr0 happens to be aligned by chance, ptr1 is not. assert!(!ptr0.is_aligned() || !ptr1.is_aligned()); // And also test that we can get the addr of a packed struct then do a member read from it. unsafe { let ptr = std::ptr::addr_of!(memory[0]); let _tail = (*ptr).tail; let ptr = std::ptr::addr_of!(memory[1]); let _tail = (*ptr).tail; } }