use serde::{Deserialize, Serialize};
fn d<T>() -> T {
    unimplemented!()
}

#[derive(Deserialize, Serialize)]
struct Unit;
////////////////////////////////////////////////////////////////////////////////

#[derive(Deserialize, Serialize)]
struct Tuple0();

#[derive(Deserialize, Serialize)]
struct Tuple1(u8);

#[derive(Deserialize, Serialize)]
struct Tuple2(u8, u8);

#[derive(Deserialize, Serialize)]
struct Tuple1as0(#[serde(skip)] u8);

#[derive(Deserialize, Serialize)]
struct Tuple2as0(#[serde(skip)] u8, #[serde(skip)] u8);

#[derive(Deserialize, Serialize)]
struct Tuple2as1(#[serde(skip)] u8, u8);

#[derive(Deserialize, Serialize)]
struct Tuple1as0Default(#[serde(skip, default = "d")] u8);

#[derive(Deserialize, Serialize)]
struct Tuple2as0Default(
    #[serde(skip, default = "d")] u8,
    #[serde(skip, default = "d")] u8,
);

#[derive(Deserialize, Serialize)]
struct Tuple2as1Default(#[serde(skip, default = "d")] u8, #[serde(default = "d")] u8);
////////////////////////////////////////////////////////////////////////////////

#[derive(Deserialize, Serialize)]
struct Struct0 {}

#[derive(Deserialize, Serialize)]
struct Struct1 {
    a: u8,
}

#[derive(Deserialize, Serialize)]
struct Struct2as0 {
    #[serde(skip)]
    a: u8,
    #[serde(skip)]
    b: u8,
}

#[derive(Deserialize, Serialize)]
struct Struct2as1 {
    #[serde(skip)]
    a: u8,
    b: u8,
}
////////////////////////////////////////////////////////////////////////////////

#[derive(Deserialize, Serialize)]
enum ExternallyTagged {
    Unit,

    Tuple0(),
    Tuple1(u8),
    Tuple2(u8, u8),
    Tuple1as0(#[serde(skip)] u8),
    Tuple2as0(#[serde(skip)] u8, #[serde(skip)] u8),
    Tuple2as1(#[serde(skip)] u8, u8),

    Tuple1as0Default(#[serde(skip, default = "d")] u8),
    Tuple2as0Default(
        #[serde(skip, default = "d")] u8,
        #[serde(skip, default = "d")] u8,
    ),
    Tuple2as1Default(#[serde(skip, default = "d")] u8, #[serde(default = "d")] u8),

    Struct0 {},
    Struct1 {
        a: u8,
    },
    Struct2as0 {
        #[serde(skip)]
        a: u8,
        #[serde(skip)]
        b: u8,
    },
    Struct2as1 {
        #[serde(skip)]
        a: u8,
        b: u8,
    },
}
////////////////////////////////////////////////////////////////////////////////

#[derive(Deserialize, Serialize)]
#[serde(tag = "tag")]
enum InternallyTagged {
    Unit,

    // Tuple0(), FIXME
    Tuple1(u8),
    // Tuple2(u8, u8), - not supported
    Tuple1as0(#[serde(skip)] u8),
    // Tuple2as0(#[serde(skip)] u8, #[serde(skip)] u8), FIXME
    // Tuple2as1(#[serde(skip)] u8, u8), FIXME
    Tuple1as0Default(#[serde(skip, default = "d")] u8),
    // Tuple2as0Default(#[serde(skip, default = "d")] u8, #[serde(skip, default = "d")] u8), FIXME
    // Tuple2as1Default(#[serde(skip, default = "d")] u8, #[serde(default = "d")] u8), FIXME
    Struct0 {},
    Struct1 {
        a: u8,
    },
    Struct2as0 {
        #[serde(skip)]
        a: u8,
        #[serde(skip)]
        b: u8,
    },
    Struct2as1 {
        #[serde(skip)]
        a: u8,
        b: u8,
    },
}
////////////////////////////////////////////////////////////////////////////////

#[derive(Deserialize, Serialize)]
#[serde(tag = "tag", content = "content")]
enum AdjacentlyTagged {
    Unit,

    Tuple0(),
    Tuple1(u8),
    Tuple2(u8, u8),
    Tuple1as0(#[serde(skip)] u8),
    Tuple2as0(#[serde(skip)] u8, #[serde(skip)] u8),
    Tuple2as1(#[serde(skip)] u8, u8),

    Tuple1as0Default(#[serde(skip, default = "d")] u8),
    Tuple2as0Default(
        #[serde(skip, default = "d")] u8,
        #[serde(skip, default = "d")] u8,
    ),
    Tuple2as1Default(#[serde(skip, default = "d")] u8, #[serde(default = "d")] u8),

    Struct0 {},
    Struct1 {
        a: u8,
    },
    Struct2as0 {
        #[serde(skip)]
        a: u8,
        #[serde(skip)]
        b: u8,
    },
    Struct2as1 {
        #[serde(skip)]
        a: u8,
        b: u8,
    },
}
////////////////////////////////////////////////////////////////////////////////

#[derive(Deserialize, Serialize)]
#[serde(untagged)]
enum Untagged {
    Unit,

    Tuple0(),
    Tuple1(u8),
    Tuple2(u8, u8),
    Tuple1as0(#[serde(skip)] u8),
    Tuple2as0(#[serde(skip)] u8, #[serde(skip)] u8),
    Tuple2as1(#[serde(skip)] u8, u8),

    Tuple1as0Default(#[serde(skip, default = "d")] u8),
    Tuple2as0Default(
        #[serde(skip, default = "d")] u8,
        #[serde(skip, default = "d")] u8,
    ),
    Tuple2as1Default(#[serde(skip, default = "d")] u8, #[serde(default = "d")] u8),

    Struct0 {},
    Struct1 {
        a: u8,
    },
    Struct2as0 {
        #[serde(skip)]
        a: u8,
        #[serde(skip)]
        b: u8,
    },
    Struct2as1 {
        #[serde(skip)]
        a: u8,
        b: u8,
    },
}