如何实现具有生命周期的 trait 实现 trait

Question

How do I do the following?

trait Foo {}
trait Bar<'a> {}

impl<S> S for Bar<'_> where S: Foo {}

Answer 1

There is indeed @user4815162342's answer:

impl<'a, S> Bar<'a> for S where S: Foo {}

You can also add default implementations to your trait:

trait Bar {
    pub fn hello() {
        println!("Hello, world!");
    }
}

struct Foo {}

impl Bar for Foo {}

// ...
Foo::hello();