Comments, fix for potential move assignment leak

main.cpp

@@ -5,7 +5,7 @@
 template<class T>
 class UniquePtr {
 public:
-    /// Constructor without deleter
+    /// Constructor without custom deleter - use default deleter which just calls 'delete'
     explicit UniquePtr(T *object) : object(object), deleter([](T *object) -> void { delete object; }) {
         assert(object != nullptr);
     }
@@ -32,14 +32,20 @@ public:
 
     /// Move assignment operator
     UniquePtr &operator=(UniquePtr &&other) {
-        object = other.object;
+        Swap(other.object);
         deleter = other.deleter;
 
+        // TODO: If Swap is implemented with std::swap instead of deleting the current object, this should not be done!
+        //  However, that would mean that the old object can stay in memory unnecessarily long (until 'other' goes out of scope)
         other.object = nullptr;
     }
 
     /// Destructor
     virtual ~UniquePtr() {
+        // TODO: deleter(object) is called twice if 'Reset()' was previously called and the UniquePtr goes out of scope.
+        //  With the default deleter, this is fine since 'delete object' handles the case of the object being null.
+        //  However, with a custom deleter this may not be intended?
+        //  We'd have to introduce a new flag and an if statement here
         deleter(object);
     }
 
@@ -67,7 +73,7 @@ public:
         return returnObject;
     }
 
-    /// Reset the internal pointer to null
+    /// Reset the internal pointer to null, deleting the owned object
     void Reset() {
         deleter(object);
 
@@ -120,6 +126,7 @@ private:
 
 int TestObject::instanceCount = 0;
 
+
 void customTestObjectDeleter(TestObject *object) {
     std::cout << "Custom deleter" << std::endl;
 
@@ -151,9 +158,14 @@ int main() {
         if (pointer3) {
             std::cout << "This shouldn't happen!" << std::endl;
         }
+
+        std::cout << "Moving into a pointer which already has an object" << std::endl;
+        UniquePtr pointer4 = UniquePtr(new TestObject());
+        UniquePtr pointer5 = UniquePtr(new TestObject());
+        pointer4 = std::move(pointer5);
     }
 
-    std::cout << std::endl << "All pointers should now be out of scope!" << std::endl;
+    std::cout << std::endl << "All pointers are now out of scope, all objects should be deleted!" << std::endl;
     std::cout << TestObject::getInstanceCount() << " instances left" << std::endl;
 
     return 0;