With help of talchas

unique_types.rs

#![feature(type_macros)]

struct Zero;
struct Succ<T>(T);


macro_rules! newtype {
    ($name_:ident) => {
        get_and_inc!($name_, Zero);
    }
}

macro_rules! get_and_inc {
    ($name:ident, $ty:ty) => {
        macro_rules! newtype {
            ($name_:ident) => {
                get_and_inc!($name_, Succ<$ty>);
            }
        }
        type $name = $ty;
    }
}

newtype!(A);
newtype!(B);

fn main() {
}