trait THeader {
    fn m(&self) {
        println!("hello");
    }
}

struct Something {
    msg: Box<THeader>,
}

impl PartialEq for Something {
    fn eq(&self, other: &Something) -> bool {
        self.msg == other.msg
    }
}

#[derive(Clone, Copy, Debug, PartialEq, Eq)]
struct THeader1;
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
struct THeader2;

impl THeader for THeader1 {}
impl THeader for THeader2 {}

fn main() {
    let h1 = Something {
        msg: Box::new(THeader1 {}),
    };
    let h2 = Something {
        msg: Box::new(THeader2 {}),
    };
    if h1 == h2 {
        println!("eq");
    }
}