src/test/ui/derives/deriving-copyclone.rs

   1 // this will get a no-op Clone impl
   2 #[derive(Copy, Clone)]
   3 struct A {
   4     a: i32,
   5     b: i64
   6 }
   7
   8 // this will get a deep Clone impl
   9 #[derive(Copy, Clone)]
  10 struct B<T> {
  11     a: i32,
  12     b: T
  13 }
  14
  15 struct C; // not Copy or Clone
  16 #[derive(Clone)] struct D; // Clone but not Copy
  17
  18 fn is_copy<T: Copy>(_: T) {}
  19 fn is_clone<T: Clone>(_: T) {}
  20
  21 fn main() {
  22     // A can be copied and cloned
  23     is_copy(A { a: 1, b: 2 });
  24     is_clone(A { a: 1, b: 2 });
  25
  26     // B<i32> can be copied and cloned
  27     is_copy(B { a: 1, b: 2 });
  28     is_clone(B { a: 1, b: 2 });
  29
  30     // B<C> cannot be copied or cloned
  31     is_copy(B { a: 1, b: C }); //~ ERROR Copy
  32     is_clone(B { a: 1, b: C }); //~ ERROR Clone
  33
  34     // B<D> can be cloned but not copied
  35     is_copy(B { a: 1, b: D }); //~ ERROR Copy
  36     is_clone(B { a: 1, b: D });
  37 }