13 let a: Clam = Clam{ x: Box::new(1), y: Box::new(2) };
14 let b: Clam = Clam{ x: Box::new(10), y: Box::new(20) };
15 let z: isize = a.x + b.y;
16 //~^ ERROR cannot add `Box<isize>` to `Box<isize>`
19 let forty: Fish = Fish{ a: Box::new(40) };
20 let two: Fish = Fish{ a: Box::new(2) };
21 let answer: isize = forty.a + two.a;
22 //~^ ERROR cannot add `Box<isize>` to `Box<isize>`
23 println!("{}", answer);
24 assert_eq!(answer, 42);