How can I use nested structs?

Question

I'm new to Rust and for the first time I'm writing this sort of code:

PLAYGROUND HERE

#[tokio::main]
async fn main() {
    #[derive(Default, Clone)]
    pub struct Coach {
        id: Option<i64>,
        name: String,
        team: Option<Team>
    }

    #[derive(Default, Clone)]
    pub struct Team {
        id: Option<i64>,
        name: String,
        coach: Option<Coach>
    }
}

The error is:

error[E0072]: recursive type `Coach` has infinite size
 --> src/main.rs:4:5
  |
4 |     pub struct Coach {
  |     ^^^^^^^^^^^^^^^^ recursive type has infinite size
...
7 |         team: Option<Team>
  |               ------------ recursive without indirection
  |
help: insert some indirection (e.g., a `Box`, `Rc`, or `&`) to make `Coach` representable
  |
7 |         team: Option<Box<Team>>
  |                      ++++    +

error[E0072]: recursive type `Team` has infinite size
  --> src/main.rs:11:5
   |
11 |     pub struct Team {
   |     ^^^^^^^^^^^^^^^ recursive type has infinite size
...
14 |         coach: Option<Coach>
   |                ------------- recursive without indirection
   |
help: insert some indirection (e.g., a `Box`, `Rc`, or `&`) to make `Team` representable
   |
14 |         coach: Option<Box<Coach>>
   |                       ++++     +

For more information about this error, try `rustc --explain E0072`.

Coming from Go where something like this is easily possible, what is Rust idiomatic code?

Answer 1

add Box, since it's a "pointer"

#[tokio::main]
async fn main() {
    #[derive(Default, Clone)]
    pub struct Coach {
        id: Option<i64>,
        name: String,
        team: Option<Box<Team>>
    }

    #[derive(Default, Clone)]
    pub struct Team {
        id: Option<i64>,
        name: String,
        coach: Option<Box<Coach>>
    }
}

you could ref to https://rust-unofficial.github.io/too-many-lists/first-layout.html?highlight=box#basic-data-layout