snap.cairo

#[derive(Copy, Drop)]
struct MyStruct {
  val: felt,
}

trait MyTrait<T> {
  fn is_green(self: @T) -> bool;
}

impl RGBImpl of MyTrait::<MyStruct> {
  fn is_green(self: @MyStruct) -> bool {
    *self.val == 1
  }
}

#[test]
fn assert_is_green() {
  let green = MyStruct {val: 1};

  assert(green.is_green(), 'not green');     // <- This gives compiler error "Method `is_green` not found on type
  assert((@green).is_green(), 'not green');  // <- This works
}