How to get RefCell to an object and Rc to its part - rust

Question

I need to call a mut method on an object from one callback and another method from another callback (a timer and request animation frame in a webasm thing) on its field returned from that object. Whatever I tried I was getting various errors, mostly like 'creates a temporary which is freed while still in use'. Is it ever possible?
let mut top = Top {
item: Item {}
};
let top_rc_refcell = Rc::new(RefCell::new(top));
let top_rc_1 = Rc::clone(&top_rc_refcell);
let box_1 = Box::new(move || {
top_rc_1.borrow_mut().some_mut();
});
let top_rc_2 = Rc::clone(&top_rc_refcell);
//ref_to_item is costly so calling it from within callback is not an option
let item_rc = Rc::new(&top_rc_2.borrow().ref_to_item());
let item_rc_in_box = Rc::clone(&item_rc);
let box_2 = Box::new(move || {
item_rc_in_box.some();
});
(box_1)();
(box_2)();
Errors:
error[E0716]: temporary value dropped while borrowed
--> src/lib.rs:46:28
|
46 | let item_rc = Rc::new(&top_rc_2.borrow().ref_to_item());
| ^^^^^^^^^^^^^^^^^ - temporary value is freed at the end of this statement
| |
| creates a temporary which is freed while still in use
47 |
48 | let item_rc_in_box = Rc::clone(&item_rc);
| -------- borrow later used here
|
= note: consider using a `let` binding to create a longer lived value
error[E0716]: temporary value dropped while borrowed
--> src/lib.rs:46:28
|
46 | let item_rc = Rc::new(&top_rc_2.borrow().ref_to_item());
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ - temporary value is freed at the end of this statement
| |
| creates a temporary which is freed while still in use
47 |
48 | let item_rc_in_box = Rc::clone(&item_rc);
| -------- borrow later used here
|
= note: consider using a `let` binding to create a longer lived value
playground

Answer 1

Not exactly. You cannot create a Rc pointing to the field because the field will have to be wrapped somehow in the Rc. You can only do so for a pointer to the field, and this is pretty useless and also the source of your errors.
You need to either declare the field as Rc or just use the whole-object Rc.