Fix memory leak

src/utility/list.rs

@@ -108,13 +108,14 @@ impl<T: PartialEq> List<T> {
     /// Return true if the item has been found, otherwise return false
     /// 
     /// Worst-case complexity is O(n)
-    pub fn remove(&mut self, item: &T)-> bool {
+    pub fn remove(&mut self, item: T)-> bool {
         unsafe {
             let mut current: *mut Node<T> = self.head;
             let mut previous: *mut Node<T> = ptr::null_mut();
             while !current.is_null() {
-                if &(*current).elem == item {
+                if (*current).elem == item {
                     (*previous).next = (*current).next;
+                    drop(Box::from_raw(current).elem);
                     return true;
                 } else {
                     previous = current;
@@ -312,11 +313,11 @@ mod test {
         list.push(3);
 
         assert_eq!(list.contains(&2), true);
-        list.remove(&2);
+        list.remove(2);
         assert_eq!(list.contains(&2), false);
         assert_eq!(list.pop(), Option::Some(1));
         assert_eq!(list.pop(), Option::Some(3));
-        assert_eq!(list.pop(), Option::None);
+        assert_eq!(list.peek(), Option::None);
     }
 
     #[test]