diff --git a/src/libraries/turtle/is_functor.hpp b/src/libraries/turtle/is_functor.hpp
index 5f12b4d..0b038a8 100644
--- a/src/libraries/turtle/is_functor.hpp
+++ b/src/libraries/turtle/is_functor.hpp
@@ -31,8 +31,8 @@ namespace detail
     };
 
     MOCK_IS_FUNCTION_HELPER( has_result_type, result_type )
-    MOCK_IS_FUNCTION_HELPER( has_sig, sig< void > )
-    MOCK_IS_FUNCTION_HELPER( has_result, result< void > )
+    MOCK_IS_FUNCTION_HELPER( has_sig, template sig< void > )
+    MOCK_IS_FUNCTION_HELPER( has_result, template result< void > )
 
 #undef MOCK_IS_FUNCTION_HELPER