//@ run-pass struct List { value: T, next: Option>>, } fn to_refs(mut list: &mut List) -> Vec<&mut T> { let mut result = vec![]; loop { result.push(&mut list.value); if let Some(n) = list.next.as_mut() { list = n; } else { return result; } } } fn main() { let mut list = List { value: 1, next: None }; let vec = to_refs(&mut list); assert_eq!(vec![&mut 1], vec); }