Function can_reborrow 

pub fn can_reborrow<T: ?Sized>(obj: &T) -> bool

Returns true if reborrowing is possible.

This can be used to make an object conditionally reborrow. If this method returns true, then reborrow will not panic.

use minijinja::value::{Value, StructObject};
use minijinja_stack_ref::{reborrow, can_reborrow, scope};

struct MyObject {
    values: Vec<u32>,
}

impl StructObject for MyObject {
    fn get_field(&self, field: &str) -> Option<Value> {
        match field {
            "values" => if can_reborrow(self) {
                Some(reborrow(self, |slf, scope| {
                    scope.seq_object_ref(&slf.values[..])
                }))
            } else {
                Some(Value::from_serialize(&self.values))
            },
            _ => None
        }
    }
}