// extern crate serde; // 1.0.101

use serde::de::{self, Deserializer};
use serde::Deserialize;

fn main() {}

struct Duration {
    secs: u64,
    nanos: u32,
}

impl<'de> de::Deserialize<'de> for Duration {
    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
    where
        D: Deserializer<'de>,
    {
        // Comment out these lines and uncomment the manual impl of Deserialize
        // to make it work or just uncomment `extern crate serde;` in line 1
        #[derive(Deserialize)]
        enum Field {
            Secs,
            Nanos,
        }

        //        enum Field { Secs, Nanos };
        //
        //        impl<'de> Deserialize<'de> for Field {
        //            fn deserialize<D>(deserializer: D) -> Result<Field, D::Error>
        //            where
        //                D: Deserializer<'de>,
        //            {
        //                unimplemented!();
        //            }
        //        }

        unimplemented!();
    }
}