trait Storable {
    fn do_nothing(&self) {}
}

struct ThingA {}
struct ThingB {}

impl Storable for ThingA {}

fn main() {

    let thing_a = ThingA{};
    let thing_b = ThingB{};

    let who_knows: &Storable = &thing_a;
    let no_work: Storable = ThingB{};

}