trait Base{
    type Item;
    type Item2;
}

trait Service {
    type R;
    type E;
    type C : Base<Item = Self::R, Item2 = Self::E>;
}

struct Inner<T: Service> {
    service: T,
}

struct S1<T: Service> {
    inner: Inner<T>,
}

struct S2 {
    inner: Inner<ServiceImpl>,
}

struct ServiceImpl {}
impl Service for ServiceImpl {}

fn create() -> Service<R=u64, E=String>{ // хз что тут должно быть

}

fn main() {
   let a = S2{inner: create()};
}