trait Animal {
    fn name(&self) -> String;
}

trait Speak: Animal {
    fn speak(&self) {
        println!("{} can't speak", self.name());
    }
}

struct Dog {
    name: String
}

impl Animal for Dog {
    fn name(&self) -> String {
        self.name.clone()
    }
}

impl Speak for Dog {}


#[test]
pub fn test_nested_traits() {
    let dog = Dog { name: String::from("Fido") };
    dog.speak();  // prints "Fido can't speak"
}