// run-pass #![allow(non_camel_case_types)] use std::cell::Cell; #[derive(Debug)] struct r<'a> { i: &'a Cell, } impl<'a> Drop for r<'a> { fn drop(&mut self) { self.i.set(self.i.get() + 1); } } fn r(i: &Cell) -> r { r { i: i } } pub fn main() { let i = &Cell::new(0); // Even though these look like copies, they are guaranteed not to be { let a = r(i); let b = (a, 10); let (c, _d) = b; println!("{:?}", c); } assert_eq!(i.get(), 1); }