error[E0499]: cannot borrow `list.0.value` as mutable more than once at a time
  --> $DIR/issue-62007-assign-differing-fields.rs:16:21
   |
LL | fn to_refs<'a, T>(mut list: (&'a mut List<T>, &'a mut List<T>)) -> Vec<&'a mut T> {
   |            -- lifetime `'a` defined here
...
LL |         result.push(&mut (list.0).value);
   |                     ^^^^^^^^^^^^^^^^^^^ `list.0.value` was mutably borrowed here in the previous iteration of the loop
...
LL |             return result;
   |                    ------ returning this value requires that `list.0.value` is borrowed for `'a`

error[E0499]: cannot borrow `list.0.next` as mutable more than once at a time
  --> $DIR/issue-62007-assign-differing-fields.rs:17:26
   |
LL | fn to_refs<'a, T>(mut list: (&'a mut List<T>, &'a mut List<T>)) -> Vec<&'a mut T> {
   |            -- lifetime `'a` defined here
...
LL |         if let Some(n) = (list.0).next.as_mut() {
   |                          ^^^^^^^^^^^^^---------
   |                          |
   |                          `list.0.next` was mutably borrowed here in the previous iteration of the loop
   |                          argument requires that `list.0.next` is borrowed for `'a`

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0499`.