trait Diffable<'a> {
    type D: 'a;

    fn diff(&'a self) -> Self::D;
}

struct Edit<'a, T> {
    marker: std::marker::PhantomData<&'a T>,
}

impl<'a, T> Edit<'a, T> {
    fn new(value: &'a T) -> Self {
        Self {
            marker: std::marker::PhantomData,
        }
    }
}

//#[derive(Diffus)]
struct Foo {
    x: String,
    y: i32,
}

// Generated by derive(Diffus)
struct EditedFoo<'a> {
    x: Edit<'a, String>,
    y: Edit<'a, i32>,
}

// Generated by derive(Diffus)
impl<'a> Diffable<'a> for Foo {
    type D = EditedFoo<'a>;

    fn diff(&'a self) -> Self::D {
        EditedFoo {
            x: Edit::new(&self.x),
            y: Edit::new(&self.y),
        }
    }
}

fn main() {

}