diff --git a/single/sol/sol.hpp b/single/sol/sol.hpp
index 9d4688dc..01bcc50a 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 2017-11-17 12:20:03.514818 UTC
-// This header was generated with sol v2.18.6 (revision fa912a5)
+// Generated 2017-11-17 21:50:58.352644 UTC
+// This header was generated with sol v2.18.6 (revision 4a39020)
 // https://github.com/ThePhD/sol2
 
 #ifndef SOL_SINGLE_INCLUDE_HPP
@@ -4949,7 +4949,7 @@ namespace sol {
 		userdata = LUA_TUSERDATA,
 		lightuserdata = LUA_TLIGHTUSERDATA,
 		table = LUA_TTABLE,
-		poly = none | lua_nil | string | number | thread | table | boolean | function | userdata | lightuserdata
+		poly = -0xFFFF
 	};
 
 	inline const std::string& to_string(call_status c) {
@@ -5811,7 +5811,7 @@ namespace sol {
 			};
 			(void)detail::swallow{int(), (action(detail::demangle<Args>()), int())...};
 			addendum += ")')";
-			return type_panic_string(L, index, expected, actual, message + addendum);
+			return type_panic_string(L, index, expected, actual, message.empty() ? addendum : message + addendum);
 		}
 	};
 
diff --git a/sol/error_handler.hpp b/sol/error_handler.hpp
index 0c0bdbed..18c103f2 100644
--- a/sol/error_handler.hpp
+++ b/sol/error_handler.hpp
@@ -84,21 +84,23 @@ namespace sol {
 
 	struct constructor_handler {
 		int operator()(lua_State* L, int index, type expected, type actual, const std::string& message) const noexcept(false) {
-			return type_panic_string(L, index, expected, actual, message + " (type check failed in constructor)");
+			std::string str = "(type check failed in constructor)";
+			return type_panic_string(L, index, expected, actual, message.empty() ? str : message + " " + str);
 		}
 	};
 
 	template <typename F = void>
 	struct argument_handler {
 		int operator()(lua_State* L, int index, type expected, type actual, const std::string& message) const noexcept(false) {
-			return type_panic_string(L, index, expected, actual, message + " (bad argument to variable or function call)");
+			std::string str = "(bad argument to variable or function call)";
+			return type_panic_string(L, index, expected, actual, message.empty() ? str : message + " " + str );
 		}
 	};
 
 	template <typename R, typename... Args>
 	struct argument_handler<types<R, Args...>> {
 		int operator()(lua_State* L, int index, type expected, type actual, const std::string& message) const noexcept(false) {
-			std::string addendum = " (bad argument into '";
+			std::string addendum = "(bad argument into '";
 			addendum += detail::demangle<R>();
 			addendum += "(";
 			int marker = 0;
@@ -111,7 +113,7 @@ namespace sol {
 			};
 			(void)detail::swallow{int(), (action(detail::demangle<Args>()), int())...};
 			addendum += ")')";
-			return type_panic_string(L, index, expected, actual, message + addendum);
+			return type_panic_string(L, index, expected, actual, message.empty() ? addendum : message + " " + addendum);
 		}
 	};
 
diff --git a/sol/types.hpp b/sol/types.hpp
index b37cb67d..cbdb98d7 100644
--- a/sol/types.hpp
+++ b/sol/types.hpp
@@ -617,7 +617,7 @@ namespace sol {
 		userdata = LUA_TUSERDATA,
 		lightuserdata = LUA_TLIGHTUSERDATA,
 		table = LUA_TTABLE,
-		poly = none | lua_nil | string | number | thread | table | boolean | function | userdata | lightuserdata
+		poly = -0xFFFF
 	};
 
 	inline const std::string& to_string(call_status c) {