diff --git a/single.py b/single.py
index bd8cad79..df63616f 100644
--- a/single.py
+++ b/single.py
@@ -23,7 +23,7 @@ parser.add_argument(
     help=
     'name and location of where to place file (and forward declaration file)',
     metavar='file',
-    default='sol.hpp')
+    default=['sol.hpp'])
 parser.add_argument('--quiet', help='suppress all output', action='store_true')
 args = parser.parse_args()
 
diff --git a/single/sol/sol.hpp b/single/sol/sol.hpp
index 17353016..8ca6296d 100644
--- a/single/sol/sol.hpp
+++ b/single/sol/sol.hpp
@@ -20,8 +20,8 @@
 // CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 // This file was generated with a script.
-// Generated 2018-06-27 15:33:51.932186 UTC
-// This header was generated with sol v2.20.4 (revision 60ee53a)
+// Generated 2018-07-23 14:58:57.359452 UTC
+// This header was generated with sol v2.20.4 (revision d343264)
 // https://github.com/ThePhD/sol2
 
 #ifndef SOL_SINGLE_INCLUDE_HPP
@@ -16450,6 +16450,21 @@ namespace sol {
 			static const bool value = sizeof(test<T>(0)) == sizeof(char);
 		};
 
+		template <typename T>
+		struct has_traits_size_test {
+		private:
+			typedef std::array<char, 1> one;
+			typedef std::array<char, 2> two;
+
+			template <typename C>
+			static one test(decltype(&C::size));
+			template <typename C>
+			static two test(...);
+
+		public:
+			static const bool value = sizeof(test<T>(0)) == sizeof(char);
+		};
+
 		template <typename T>
 		using has_clear = meta::boolean<has_clear_test<T>::value>;
 
@@ -16493,7 +16508,7 @@ namespace sol {
 		using has_traits_add = meta::boolean<has_traits_add_test<T>::value>;
 
 		template <typename T>
-		using has_traits_size = meta::has_size<T>;
+		using has_traits_size = meta::boolean<has_traits_size_test<T>::value>;
 
 		template <typename T>
 		using has_traits_clear = has_clear<T>;
diff --git a/single/sol/sol_forward.hpp b/single/sol/sol_forward.hpp
index fe2766a1..921609c0 100644
--- a/single/sol/sol_forward.hpp
+++ b/single/sol/sol_forward.hpp
@@ -20,8 +20,8 @@
 // CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 // This file was generated with a script.
-// Generated 2018-06-27 15:33:52.214419 UTC
-// This header was generated with sol v2.20.4 (revision 60ee53a)
+// Generated 2018-07-23 14:58:57.506417 UTC
+// This header was generated with sol v2.20.4 (revision d343264)
 // https://github.com/ThePhD/sol2
 
 #ifndef SOL_SINGLE_INCLUDE_FORWARD_HPP
diff --git a/sol/container_traits.hpp b/sol/container_traits.hpp
index 665a3274..09332c72 100644
--- a/sol/container_traits.hpp
+++ b/sol/container_traits.hpp
@@ -340,6 +340,21 @@ namespace sol {
 			static const bool value = sizeof(test<T>(0)) == sizeof(char);
 		};
 
+		template <typename T>
+		struct has_traits_size_test {
+		private:
+			typedef std::array<char, 1> one;
+			typedef std::array<char, 2> two;
+
+			template <typename C>
+			static one test(decltype(&C::size));
+			template <typename C>
+			static two test(...);
+
+		public:
+			static const bool value = sizeof(test<T>(0)) == sizeof(char);
+		};
+
 		template <typename T>
 		using has_clear = meta::boolean<has_clear_test<T>::value>;
 
@@ -383,7 +398,7 @@ namespace sol {
 		using has_traits_add = meta::boolean<has_traits_add_test<T>::value>;
 
 		template <typename T>
-		using has_traits_size = meta::has_size<T>;
+		using has_traits_size = meta::boolean<has_traits_size_test<T>::value>;
 
 		template <typename T>
 		using has_traits_clear = has_clear<T>;