error[E0599]: no function or associated item named `query` found for struct `UserOrder` in the current scope
  --> tests/ui/query_on_child.rs:12:24
   |
 7 | struct UserOrder {
   | ---------------- function or associated item `query` not found for this struct
...
12 |     let _ = UserOrder::query();
   |                        ^^^^^ function or associated item not found in `UserOrder`
   |
   = help: items from traits can only be used if the trait is implemented and in scope
   = note: the following traits define an item `query`, perhaps you need to implement one of them:
           candidate #1: `FlussoIndex`
           candidate #2: `FlussoMultiDocument`
