// run-pass #![allow(unused_assignments)] #![allow(unions_with_drop_fields)] // Drop works for union itself. #![feature(untagged_unions)] struct S; union U { a: S } impl Drop for S { fn drop(&mut self) { unsafe { CHECK += 10; } } } impl Drop for U { fn drop(&mut self) { unsafe { CHECK += 1; } } } static mut CHECK: u8 = 0; fn main() { unsafe { let mut u = U { a: S }; assert_eq!(CHECK, 0); u = U { a: S }; assert_eq!(CHECK, 1); // union itself is assigned, union is dropped, field is not dropped u.a = S; assert_eq!(CHECK, 11); // union field is assigned, field is dropped } }