+
+
+#[test]
+fn test_drop() {
+ static mut DROPS: i32 = 0;
+ struct Elem;
+ impl Drop for Elem {
+ fn drop(&mut self) {
+ unsafe {
+ DROPS += 1;
+ }
+ }
+ }
+
+ let mut ring = LinkedList::new();
+ ring.push_back(Elem);
+ ring.push_front(Elem);
+ ring.push_back(Elem);
+ ring.push_front(Elem);
+ drop(ring);
+
+ assert_eq!(unsafe { DROPS }, 4);
+}
+
+#[test]
+fn test_drop_with_pop() {
+ static mut DROPS: i32 = 0;
+ struct Elem;
+ impl Drop for Elem {
+ fn drop(&mut self) {
+ unsafe {
+ DROPS += 1;
+ }
+ }
+ }
+
+ let mut ring = LinkedList::new();
+ ring.push_back(Elem);
+ ring.push_front(Elem);
+ ring.push_back(Elem);
+ ring.push_front(Elem);
+
+ drop(ring.pop_back());
+ drop(ring.pop_front());
+ assert_eq!(unsafe { DROPS }, 2);
+
+ drop(ring);
+ assert_eq!(unsafe { DROPS }, 4);
+}
+
+#[test]
+fn test_drop_clear() {
+ static mut DROPS: i32 = 0;
+ struct Elem;
+ impl Drop for Elem {
+ fn drop(&mut self) {
+ unsafe {
+ DROPS += 1;
+ }
+ }
+ }
+
+ let mut ring = LinkedList::new();
+ ring.push_back(Elem);
+ ring.push_front(Elem);
+ ring.push_back(Elem);
+ ring.push_front(Elem);
+ ring.clear();
+ assert_eq!(unsafe { DROPS }, 4);
+
+ drop(ring);
+ assert_eq!(unsafe { DROPS }, 4);
+}
+
+#[test]
+fn test_drop_panic() {
+ static mut DROPS: i32 = 0;
+
+ struct D(bool);
+
+ impl Drop for D {
+ fn drop(&mut self) {
+ unsafe {
+ DROPS += 1;
+ }
+
+ if self.0 {
+ panic!("panic in `drop`");
+ }
+ }
+ }
+
+ let mut q = LinkedList::new();
+ q.push_back(D(false));
+ q.push_back(D(false));
+ q.push_back(D(false));
+ q.push_back(D(false));
+ q.push_back(D(false));
+ q.push_front(D(false));
+ q.push_front(D(false));
+ q.push_front(D(true));
+
+ catch_unwind(move || drop(q)).ok();
+
+ assert_eq!(unsafe { DROPS }, 8);
+}