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, &'a mut List)) -> 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, &'a mut List)) -> 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`.