trait Backend {
    fn backend() {
        println!("I am a backend!");
    }
}

trait SupportsType<Other> {
    fn convert_type() {
        println!("I can convert this type!");
    }
}

mod A {
    use super::*;
    pub struct BackendA;

    impl Backend for BackendA {}
    impl SupportsType<BackendA> for *const str {}
}

mod B {
    use super::*;
    pub struct BackendB;

    impl Backend for BackendB {}
    impl SupportsType<BackendB> for *const str {}
}

impl<Back: Backend> SupportsType<Back> for *const str {}

fn main() {
}