diff --git a/sprout/type_traits/is_convert_constructible.hpp b/sprout/type_traits/is_convert_constructible.hpp
index ffa192e9..d1b46809 100644
--- a/sprout/type_traits/is_convert_constructible.hpp
+++ b/sprout/type_traits/is_convert_constructible.hpp
@@ -21,8 +21,7 @@ namespace sprout {
 		template<typename T>
 		struct is_convert_constructible_test {
 		public:
-			template<typename To = T>
-			static sprout::true_type test(To);
+			static sprout::true_type test(T);
 			static sprout::false_type test(...);
 		};
 	}	// namespace detail
@@ -32,8 +31,8 @@ namespace sprout {
 	{};
 
 #if SPROUT_USE_VARIABLE_TEMPLATES
-	template<typename T>
-	SPROUT_STATIC_CONSTEXPR bool is_convert_constructible_v = sprout::is_convert_constructible<T>::value;
+	template<typename T, typename Arg>
+	SPROUT_STATIC_CONSTEXPR bool is_convert_constructible_v = sprout::is_convert_constructible<T, Arg>::value;
 #endif	// #if SPROUT_USE_VARIABLE_TEMPLATES
 }	// namespace sprout
 
diff --git a/testspr/iterator.hpp b/testspr/iterator.hpp
index 8858a7d8..9a3f2852 100644
--- a/testspr/iterator.hpp
+++ b/testspr/iterator.hpp
@@ -15,6 +15,8 @@
 #include <sprout/iterator/prev.hpp>
 #include <sprout/iterator/distance.hpp>
 #include <sprout/utility/swap.hpp>
+#include <sprout/type_traits/is_convert_constructible.hpp>
+#include <sprout/type_traits/enabler_if.hpp>
 
 namespace testspr {
 	//
@@ -47,11 +49,11 @@ namespace testspr {
 		explicit SPROUT_CONSTEXPR reduct_iterator(iterator_type it)
 			: current(it)
 		{}
-		template<typename U, typename V>
+		template<typename U, typename V, typename sprout::enabler_if<sprout::is_convert_constructible<Iterator, U>::value>::type = sprout::enabler>
 		SPROUT_CONSTEXPR reduct_iterator(reduct_iterator<U, V> const& it)
 			: current(it.base())
 		{}
-		template<typename U, typename V>
+		template<typename U, typename V, typename sprout::enabler_if<sprout::is_convert_constructible<Iterator, U>::value>::type = sprout::enabler>
 		reduct_iterator& operator=(reduct_iterator<U, V> const& it) {
 			reduct_iterator temp(it);
 			temp.swap(*this);