36 /// * If the list is empty, then `first` is null. Otherwise, `first` points at the `ListLinks`
37 ///   field of the first element in the list.
42     first: *mut ListLinksFields,  field
241             first: ptr::null_mut(),  in new()
248         self.first.is_null()  in is_empty()
253     /// Returns a pointer to the newly inserted element. Never changes `self.first` unless the list
285             self.first = item;  in insert_inner()
307         // * `self.first` is null or in the list.  in push_back()
308         // * `self.first` is only null if the list is empty.  in push_back()
309         unsafe { self.insert_inner(item, self.first) };  in push_back()
315         // * `self.first` is null or in the list.  in push_front()
316         // * `self.first` is only null if the list is empty.  in push_front()
317         let new_elem = unsafe { self.insert_inner(item, self.first) };  in push_front()
320         self.first = new_elem;  in push_front()
325         if self.first.is_null() {  in pop_back()
330         let last = unsafe { (*self.first).prev };  in pop_back()
335     /// Removes the first item from this list.
337         if self.first.is_null() {  in pop_front()
341         // SAFETY: The first item of this list is in this list.  in pop_front()
342         Some(unsafe { self.remove_internal(self.first) })  in pop_front()
434         //  * If `item` was not the first item, then `self.first` should remain unchanged.  in remove_internal_inner()
435         //  * If `item` was the first item and there is another item, then we just updated  in remove_internal_inner()
436         //    `prev->next` to `next`, which is the new first item, and setting `item->next` to null  in remove_internal_inner()
439         //    `item->next` to null, so this correctly sets `first` to null now that the list is  in remove_internal_inner()
441         if self.first == item {  in remove_internal_inner()
445             self.first = unsafe { (*prev).next };  in remove_internal_inner()
462         // First, we insert the elements into `self`. At the end, we make `other` empty.  in push_all_back()
465             self.first = other.first;  in push_all_back()
467             let other_first = other.first;  in push_all_back()
470             let self_first = self.first;  in push_all_back()
476             // update `self.first` because the first element of `self` does not change.  in push_all_back()
486         other.first = ptr::null_mut();  in push_all_back()
489     /// Returns a cursor that points before the first element of the list.
491         // INVARIANT: `self.first` is in this list.  in cursor_front()
493             next: self.first,  in cursor_front()
510         // at the first element of the same list.  in iter()
512             current: self.first,  in iter()
513             stop: self.first,  in iter()
539 /// * The `stop` pointer is equal to the `first` field of that [`List`].
619 /// // Use a cursor to remove the first element with the given value.
731         let first = self.list.first;  in prev_ptr()  localVariable
732         if next == first {  in prev_ptr()
733             // We are before the first element.  in prev_ptr()
739             // the same as `(*first).prev`.  in prev_ptr()
740             next = first;  in prev_ptr()
743         // SAFETY: `next` can't be null, because then `first` must also be null, but in that case  in prev_ptr()
744         // we would have exited at the `next == first` check. Thus, `next` is an element in the  in prev_ptr()
794         if next == self.list.first {  in move_next()
805     /// If the cursor is before the first element, then this call does nothing. This call returns
808         if self.next == self.list.first {  in move_prev()
820             self.list.first  in insert_inner()
826         // * if `ptr` is null, then `self.list.first` is null so the list is empty.  in insert_inner()
828         if self.next == self.list.first {  in insert_inner()
830             self.list.first = item;  in insert_inner()
907         //   access requires first releasing the immutable borrow on the `CursorPeek`.  in arc()
933         // requires first releasing the immutable borrow on the `CursorPeek`.  in deref()