//@ run-pass #![allow(dead_code)] use std::mem::{size_of, size_of_val, align_of, align_of_val}; #[repr(align(16))] pub union U16 { a: u8, b: u32 } fn main() { assert_eq!(align_of::(), 16); assert_eq!(size_of::(), 16); let u = U16 { a: 10 }; unsafe { assert_eq!(align_of_val(&u.a), 1); assert_eq!(size_of_val(&u.a), 1); assert_eq!(u.a, 10); } let u = U16 { b: 11 }; unsafe { assert_eq!(align_of_val(&u.b), 4); assert_eq!(size_of_val(&u.b), 4); assert_eq!(u.b, 11); } hybrid::check_hybrid(); } mod hybrid { use std::mem::{size_of, align_of}; #[repr(align(16))] #[derive(Copy, Clone)] struct S1 { a: u16, b: u8, } #[repr(align(32))] union U { s: S1, c: u16, } #[repr(align(64))] struct S2 { d: u8, u: U, } pub fn check_hybrid() { assert_eq!(align_of::(), 16); assert_eq!(size_of::(), 16); assert_eq!(align_of::(), 32); assert_eq!(size_of::(), 32); assert_eq!(align_of::(), 64); assert_eq!(size_of::(), 64); } }