enum Thing {
    V1,
    V2,
    Other(u32)
}

impl From<Thing> for Option<u32> {
    fn from(thing: Thing) -> Option<u32> {
        match thing {
            Thing::V1 | Thing::V2 => None,
            Thing::Other(x) => Some(x),
        }
    }
}

fn main() {
    let x = Thing::V1;
    let y = Thing::V2;
    let z = Thing::Other(5);
    let zz: Option<u32> = z.into();

    println!(
        "{:?}, {:?}, {:?}",
        Option::<u32>::from(x),
        Option::<u32>::from(y),
        zz
    );
}