diff --git a/sol/inheritance.hpp b/sol/inheritance.hpp
index 9c0cad75..cd452636 100644
--- a/sol/inheritance.hpp
+++ b/sol/inheritance.hpp
@@ -116,6 +116,7 @@ namespace sol {
 			static int type_unique_cast(void* source_data, void* target_data, const string_view& ti, const string_view& rebind_ti) {
 				typedef unique_usertype_traits<U> uu_traits;
 				typedef typename uu_traits::template rebind_base<void> rebind_t;
+				typedef std::conditional_t<std::is_void<rebind_t>::value, types<>, bases_t> cond_bases_t;
 				string_view this_rebind_ti = usertype_traits<rebind_t>::qualified_name();
 				if (rebind_ti != this_rebind_ti) {
 					// this is not even of the same unique type
@@ -123,10 +124,10 @@ namespace sol {
 				}
 				string_view this_ti = usertype_traits<T>::qualified_name();
 				if (ti == this_ti) {
-					// 
+					// direct match, return 1
 					return 1;
 				}
-				return type_unique_cast_bases<U>(bases_t(), source_data, target_data, ti);
+				return type_unique_cast_bases<U>(cond_bases_t(), source_data, target_data, ti);
 			}
 		};
 
@@ -137,6 +138,6 @@ namespace sol {
 } // namespace sol
 
 #define SOL_BASE_CLASSES(T, ...) template <> struct ::sol::base<T> : ::std::true_type { typedef ::sol::types<__VA_ARGS__> type; };
-//#define SOL_DERIVED_CLASSES(T, ...) template <> struct ::sol::derive<T> : ::std::true_type { typedef ::sol::types<__VA_ARGS__> type; };
+#define SOL_DERIVED_CLASSES(T, ...) template <> struct ::sol::derive<T> : ::std::true_type { typedef ::sol::types<__VA_ARGS__> type; };
 
 #endif // SOL_INHERITANCE_HPP
diff --git a/sol/stack_core.hpp b/sol/stack_core.hpp
index 70853d7e..f0962555 100644
--- a/sol/stack_core.hpp
+++ b/sol/stack_core.hpp
@@ -447,9 +447,7 @@ namespace sol {
 			void* memory = lua_touserdata(L, 1);
 			memory = align_usertype_unique_destructor(memory);
 			unique_destructor& dx = *static_cast<unique_destructor*>(memory);
-			memory = static_cast<void*>(static_cast<char*>(memory) + sizeof(unique_destructor));
 			memory = align_usertype_unique_tag<true>(memory);
-			memory = static_cast<void*>(static_cast<char*>(memory) + sizeof(unique_tag));
 			(dx)(memory);
 			return 0;
 		}
diff --git a/sol/stack_get_qualified.hpp b/sol/stack_get_qualified.hpp
index d5e765fd..78d9b4a0 100644
--- a/sol/stack_get_qualified.hpp
+++ b/sol/stack_get_qualified.hpp
@@ -33,6 +33,7 @@ namespace stack {
 	struct qualified_getter<X, std::enable_if_t<
 		!std::is_reference<X>::value 
 		&& is_unique_usertype<meta::unqualified_t<X>>::value
+		&& !std::is_void<typename unique_usertype_traits<meta::unqualified_t<X>>::template rebind_base<void>>::value
 	>> {
 		typedef unique_usertype_traits<meta::unqualified_t<X>> u_traits;
 		typedef typename u_traits::type T;
diff --git a/sol/stack_push.hpp b/sol/stack_push.hpp
index 0f3541f9..16225005 100644
--- a/sol/stack_push.hpp
+++ b/sol/stack_push.hpp
@@ -144,8 +144,10 @@ namespace stack {
 
 	template <typename T>
 	struct pusher<T, std::enable_if_t<is_unique_usertype<T>::value>> {
-		typedef typename unique_usertype_traits<T>::type P;
-		typedef typename unique_usertype_traits<T>::actual_type Real;
+		typedef unique_usertype_traits<T> u_traits;
+		typedef typename u_traits::type P;
+		typedef typename u_traits::actual_type Real;
+		typedef typename u_traits::template rebind_base<void> rebind_t;
 
 		template <typename Arg, meta::enable<std::is_base_of<Real, meta::unqualified_t<Arg>>> = meta::enabler>
 		static int push(lua_State* L, Arg&& arg) {