#156: footprinting: support std::list::iterator in libc++

src/checkpoint/container/list_serialize.h

@@ -106,21 +106,35 @@ inline void serialize(Serializer& s, std::deque<T>& lst) {
   serializeOrderedContainer(s, lst);
 }
 
-// FIXME: 'typename std::list<T>::iterator' doesn't work here
-//
-// this depends on the (standard library) implementation details and
-// doesn't work when libc++ is used
-// last resort would be to use '#if defined(_LIBCPP_VERSION)))'
+
+/**
+ * Note: 'typename std::list<T>::iterator' doesn't work here.
+ * This depends on the (standard library) implementation details and requires
+ * checking for '_LIBCPP_VERSION' for libc++ to work.
+ */
+#if defined(_LIBCPP_VERSION)
+template <
+  typename SerializerT,
+  typename T,
+  typename = std::enable_if_t<
+    std::is_same<SerializerT, checkpoint::Footprinter>::value
+  >
+>
+inline void serialize(SerializerT& s, const std::__list_iterator<T>& iter) {
+  s.countBytes(iter);
+}
+#else
 template <
   typename SerializerT,
   typename T,
   typename = std::enable_if_t<
     std::is_same<SerializerT, checkpoint::Footprinter>::value
   >
 >
-inline void serialize(SerializerT& s, std::_List_iterator<T>& iter) {
+inline void serialize(SerializerT& s, const std::_List_iterator<T>& iter) {
   s.countBytes(iter);
 }
+#endif
 
 } /* end namespace checkpoint */