33 /// * If the list is empty, then `first` is null. Otherwise, `first` points at the `ListLinks`
34 ///   field of the first element in the list.
39     first: *mut ListLinksFields,  field
238             first: ptr::null_mut(),  in new()
245         self.first.is_null()  in is_empty()
262         if self.first.is_null() {  in push_back()
263             self.first = item;  in push_back()
271             let next = self.first;  in push_back()
302         if self.first.is_null() {  in push_front()
310             let next = self.first;  in push_front()
323         self.first = item;  in push_front()
328         if self.first.is_null() {  in pop_back()
333         let last = unsafe { (*self.first).prev };  in pop_back()
338     /// Removes the first item from this list.
340         if self.first.is_null() {  in pop_front()
344         // SAFETY: The first item of this list is in this list.  in pop_front()
345         Some(unsafe { self.remove_internal(self.first) })  in pop_front()
436         //  * If `item` was not the first item, then `self.first` should remain unchanged.  in remove_internal_inner()
437         //  * If `item` was the first item and there is another item, then we just updated  in remove_internal_inner()
438         //    `prev->next` to `next`, which is the new first item, and setting `item->next` to null  in remove_internal_inner()
441         //    `item->next` to null, so this correctly sets `first` to null now that the list is  in remove_internal_inner()
443         if self.first == item {  in remove_internal_inner()
447             self.first = unsafe { (*prev).next };  in remove_internal_inner()
464         // First, we insert the elements into `self`. At the end, we make `other` empty.  in push_all_back()
467             self.first = other.first;  in push_all_back()
469             let other_first = other.first;  in push_all_back()
472             let self_first = self.first;  in push_all_back()
478             // update `self.first` because the first element of `self` does not change.  in push_all_back()
488         other.first = ptr::null_mut();  in push_all_back()
491     /// Returns a cursor to the first element of the list.
495         if self.first.is_null() {  in cursor_front()
499                 current: self.first,  in cursor_front()
508         // at the first element of the same list.  in iter()
510             current: self.first,  in iter()
511             stop: self.first,  in iter()
537 /// * The `stop` pointer is equal to the `first` field of that [`List`].
600         //   mutable access requires first releasing the immutable borrow on the cursor.  in current()
611         if next == self.list.first {  in next()
628         if self.current == self.list.first {  in prev()