diff --git a/sprout/container/std/complex.hpp b/sprout/container/std/complex.hpp
index 174890c5..88175906 100644
--- a/sprout/container/std/complex.hpp
+++ b/sprout/container/std/complex.hpp
@@ -9,8 +9,8 @@
 #define SPROUT_CONTAINER_STD_COMPLEX_HPP
 
 #include <complex>
-#include <type_traits>
 #include <stdexcept>
+#include <type_traits>
 #include <sprout/workaround/std/cstddef.hpp>
 #include <sprout/utility/forward.hpp>
 #include <sprout/container/traits.hpp>
@@ -25,7 +25,7 @@ namespace sprout {
 			operator()(Complex const& c, Index i) const {
 				return i == 0 ? c.real()
 					: i == 1 ? c.imag()
-					: throw std::out_of_range("std_complex_at<>: index out of range")
+					: throw std::out_of_range("std_complex_at: index out of range")
 					;
 			}
 		};
diff --git a/sprout/cstdlib/div.hpp b/sprout/cstdlib/div.hpp
index df38f754..0bf02507 100644
--- a/sprout/cstdlib/div.hpp
+++ b/sprout/cstdlib/div.hpp
@@ -13,6 +13,7 @@
 
 #include <cstdlib>
 #include <functional>
+#include <stdexcept>
 #include <type_traits>
 #include <tuple>
 #include <sprout/config.hpp>
@@ -29,7 +30,6 @@
 #include <sprout/type_traits/identity.hpp>
 #include <sprout/detail/nil_base.hpp>
 #include <sprout/detail/static_size.hpp>
-#include <sprout/assert.hpp>
 
 namespace sprout {
 	//
@@ -348,7 +348,7 @@ namespace sprout {
 		{
 			return i == 0 ? d.quot
 				: i == 1 ? d.rem
-				: (SPROUT_ASSERT(i < 2), d.quot)
+				: (throw std::out_of_range("div_at: index out of range"), d.quot)
 				;
 		}
 		template<typename Div>
@@ -358,7 +358,7 @@ namespace sprout {
 		{
 			return i == 0 ? d.quot
 				: i == 1 ? d.rem
-				: (SPROUT_ASSERT(i < 2), d.quot)
+				: (throw std::out_of_range("div_at: index out of range"), d.quot)
 				;
 		}
 
diff --git a/sprout/static_warning.hpp b/sprout/static_warning.hpp
index 9871db7d..c8a82b2d 100644
--- a/sprout/static_warning.hpp
+++ b/sprout/static_warning.hpp
@@ -21,7 +21,7 @@ namespace sprout {
 		template<typename Message>
 		static void warn() {}
 	};
-	template <>
+	template<>
 	struct static_warning<false> {
 		template<typename Message>
 		static void warn() {
diff --git a/sprout/type_traits/common_type.hpp b/sprout/type_traits/common_type.hpp
index 971c3072..d8ed4396 100644
--- a/sprout/type_traits/common_type.hpp
+++ b/sprout/type_traits/common_type.hpp
@@ -38,7 +38,7 @@ namespace sprout {
 			: public sprout::detail::undecayed_common_type_impl<void, typename sprout::detail::undecayed_common_type2<T1, T2>::type, Tail...>
 		{};
 	}	// namespace detail
-	template <typename... Types>
+	template<typename... Types>
 	struct undecayed_common_type
 		: public sprout::detail::undecayed_common_type_impl<void, Types...>
 	{};
@@ -58,7 +58,7 @@ namespace sprout {
 			: public std::decay<typename CommonType::type>
 		{};
 	}	// namespace detail
-	template <typename... Types>
+	template<typename... Types>
 	struct common_type
 		: public sprout::detail::common_type_impl<sprout::undecayed_common_type<Types...> >
 	{};
diff --git a/sprout/type_traits/conjunction.hpp b/sprout/type_traits/conjunction.hpp
new file mode 100644
index 00000000..27955098
--- /dev/null
+++ b/sprout/type_traits/conjunction.hpp
@@ -0,0 +1,29 @@
+/*=============================================================================
+  Copyright (c) 2011-2016 Bolero MURAKAMI
+  https://github.com/bolero-MURAKAMI/Sprout
+
+  Distributed under the Boost Software License, Version 1.0. (See accompanying
+  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+=============================================================================*/
+#ifndef SPROUT_TYPE_TRAITS_CONJUNCTION_HPP
+#define SPROUT_TYPE_TRAITS_CONJUNCTION_HPP
+
+#include <sprout/config.hpp>
+#include <sprout/tpp/algorithm/all_of.hpp>
+
+namespace sprout {
+	//
+	// conjunction
+	//
+	template<typename... Types>
+	struct conjunction
+		: public sprout::tpp::all_of<Types...>
+	{};
+
+#if SPROUT_USE_VARIABLE_TEMPLATES
+	template<typename... Types>
+	SPROUT_STATIC_CONSTEXPR bool conjunction_v = sprout::conjunction<Types...>::value;
+#endif	// #if SPROUT_USE_VARIABLE_TEMPLATES
+}	// namespace sprout
+
+#endif	// #ifndef SPROUT_TYPE_TRAITS_CONJUNCTION_HPP
diff --git a/sprout/type_traits/disjunction.hpp b/sprout/type_traits/disjunction.hpp
new file mode 100644
index 00000000..3e224c52
--- /dev/null
+++ b/sprout/type_traits/disjunction.hpp
@@ -0,0 +1,29 @@
+/*=============================================================================
+  Copyright (c) 2011-2016 Bolero MURAKAMI
+  https://github.com/bolero-MURAKAMI/Sprout
+
+  Distributed under the Boost Software License, Version 1.0. (See accompanying
+  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+=============================================================================*/
+#ifndef SPROUT_TYPE_TRAITS_DISJUNCTION_HPP
+#define SPROUT_TYPE_TRAITS_DISJUNCTION_HPP
+
+#include <sprout/config.hpp>
+#include <sprout/tpp/algorithm/any_of.hpp>
+
+namespace sprout {
+	//
+	// disjunction
+	//
+	template<typename... Types>
+	struct disjunction
+		: public sprout::tpp::any_of<Types...>
+	{};
+
+#if SPROUT_USE_VARIABLE_TEMPLATES
+	template<typename... Types>
+	SPROUT_STATIC_CONSTEXPR bool disjunction_v = sprout::disjunction<Types...>::value;
+#endif	// #if SPROUT_USE_VARIABLE_TEMPLATES
+}	// namespace sprout
+
+#endif	// #ifndef SPROUT_TYPE_TRAITS_DISJUNCTION_HPP
diff --git a/sprout/type_traits/enable_if_has_type.hpp b/sprout/type_traits/enable_if_has_type.hpp
index 4f4e80ec..c0c6a38d 100644
--- a/sprout/type_traits/enable_if_has_type.hpp
+++ b/sprout/type_traits/enable_if_has_type.hpp
@@ -19,6 +19,11 @@ namespace sprout {
 	public:
 		typedef R type;
 	};
+
+#if SPROUT_USE_TEMPLATE_ALIASES
+	template<typename T, typename R = void>
+	using enable_if_has_type_t = typename sprout::enable_if_has_type<T, R>::type;
+#endif	// #if SPROUT_USE_TEMPLATE_ALIASES
 }	// namespace sprout
 
 #endif	// #ifndef SPROUT_TYPE_TRAITS_ENABLE_IF_HAS_TYPE_HPP
diff --git a/sprout/type_traits/is_nothrow_swappable.hpp b/sprout/type_traits/is_nothrow_swappable.hpp
new file mode 100644
index 00000000..a61ca4c2
--- /dev/null
+++ b/sprout/type_traits/is_nothrow_swappable.hpp
@@ -0,0 +1,29 @@
+/*=============================================================================
+  Copyright (c) 2011-2016 Bolero MURAKAMI
+  https://github.com/bolero-MURAKAMI/Sprout
+
+  Distributed under the Boost Software License, Version 1.0. (See accompanying
+  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+=============================================================================*/
+#ifndef SPROUT_TYPE_TRAITS_IS_NOTHROW_SWAPPABLE_HPP
+#define SPROUT_TYPE_TRAITS_IS_NOTHROW_SWAPPABLE_HPP
+
+#include <sprout/config.hpp>
+#include <sprout/type_traits/is_nothrow_swappable_with.hpp>
+
+namespace sprout {
+	//
+	// is_nothrow_swappable
+	//
+	template<typename T>
+	struct is_nothrow_swappable
+		: public sprout::is_nothrow_swappable_with<T&, T&>
+	{};
+
+#if SPROUT_USE_VARIABLE_TEMPLATES
+	template<typename T>
+	SPROUT_STATIC_CONSTEXPR bool is_nothrow_swappable_v = sprout::is_nothrow_swappable<T>::value;
+#endif	// #if SPROUT_USE_VARIABLE_TEMPLATES
+}	// namespace sprout
+
+#endif	// #ifndef SPROUT_TYPE_TRAITS_IS_NOTHROW_SWAPPABLE_HPP
diff --git a/sprout/type_traits/is_nothrow_swappable_with.hpp b/sprout/type_traits/is_nothrow_swappable_with.hpp
new file mode 100644
index 00000000..455ca69c
--- /dev/null
+++ b/sprout/type_traits/is_nothrow_swappable_with.hpp
@@ -0,0 +1,53 @@
+/*=============================================================================
+  Copyright (c) 2011-2016 Bolero MURAKAMI
+  https://github.com/bolero-MURAKAMI/Sprout
+
+  Distributed under the Boost Software License, Version 1.0. (See accompanying
+  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+=============================================================================*/
+#ifndef SPROUT_TYPE_TRAITS_IS_NOTHROW_SWAPPABLE_WITH_HPP
+#define SPROUT_TYPE_TRAITS_IS_NOTHROW_SWAPPABLE_WITH_HPP
+
+#include <utility>
+#include <sprout/config.hpp>
+#include <sprout/type_traits/integral_constant.hpp>
+#include <sprout/type_traits/is_swappable_with.hpp>
+
+namespace sprout_nothrow_swappable_detail {
+	using std::swap;
+
+	template<typename T, typename U>
+	struct is_nothrow_swappable_with
+		: public sprout::bool_constant<
+			SPROUT_NOEXCEPT_EXPR(swap(std::declval<T>(), std::declval<U>()))
+				&& SPROUT_NOEXCEPT_EXPR(swap(std::declval<U>(), std::declval<T>()))
+		>::type
+	{};
+}	// namespace sprout_nothrow_swappable_detail
+
+namespace sprout {
+	namespace detail {
+		template<typename T, typename U, bool = false>
+		struct is_nothrow_swappable_with_impl
+			: public sprout::false_type
+		{};
+		template<typename T, typename U>
+		struct is_nothrow_swappable_with_impl<T, U, true>
+			: public sprout_nothrow_swappable_detail::is_nothrow_swappable_with<T, U>
+		{};
+	}	// namespace detail
+	//
+	// is_nothrow_swappable_with
+	//
+	template<typename T, typename U>
+	struct is_nothrow_swappable_with
+		: public sprout::detail::is_nothrow_swappable_with_impl<T, U, sprout::is_swappable_with<T, U>::value>
+	{};
+
+#if SPROUT_USE_VARIABLE_TEMPLATES
+	template<typename T, typename U>
+	SPROUT_STATIC_CONSTEXPR bool is_nothrow_swappable_with_v = sprout::is_nothrow_swappable_with<T>::value;
+#endif	// #if SPROUT_USE_VARIABLE_TEMPLATES
+}	// namespace sprout
+
+#endif	// #ifndef SPROUT_TYPE_TRAITS_IS_NOTHROW_SWAPPABLE_WITH_HPP
diff --git a/sprout/type_traits/is_signed.hpp b/sprout/type_traits/is_signed.hpp
index 57266187..57278b4a 100644
--- a/sprout/type_traits/is_signed.hpp
+++ b/sprout/type_traits/is_signed.hpp
@@ -27,7 +27,7 @@ namespace sprout {
 			: public sprout::detail::type_traits_wrapper<std::is_signed<T> >
 		{};
 	}	// namespace detail
-	template <typename T>
+	template<typename T>
 	struct is_signed
 		: public sprout::detail::is_signed_impl<T>
 	{};
diff --git a/sprout/type_traits/is_swappable.hpp b/sprout/type_traits/is_swappable.hpp
new file mode 100644
index 00000000..b36f9c1c
--- /dev/null
+++ b/sprout/type_traits/is_swappable.hpp
@@ -0,0 +1,29 @@
+/*=============================================================================
+  Copyright (c) 2011-2016 Bolero MURAKAMI
+  https://github.com/bolero-MURAKAMI/Sprout
+
+  Distributed under the Boost Software License, Version 1.0. (See accompanying
+  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+=============================================================================*/
+#ifndef SPROUT_TYPE_TRAITS_IS_SWAPPABLE_HPP
+#define SPROUT_TYPE_TRAITS_IS_SWAPPABLE_WITH_HPP
+
+#include <sprout/config.hpp>
+#include <sprout/type_traits/is_swappable_with.hpp>
+
+namespace sprout {
+	//
+	// is_swappable
+	//
+	template<typename T>
+	struct is_swappable
+		: public sprout::is_swappable_with<T&, T&>
+	{};
+
+#if SPROUT_USE_VARIABLE_TEMPLATES
+	template<typename T>
+	SPROUT_STATIC_CONSTEXPR bool is_swappable_v = sprout::is_swappable<T>::value;
+#endif	// #if SPROUT_USE_VARIABLE_TEMPLATES
+}	// namespace sprout
+
+#endif	// #ifndef SPROUT_TYPE_TRAITS_IS_SWAPPABLE_HPP
diff --git a/sprout/type_traits/is_swappable_with.hpp b/sprout/type_traits/is_swappable_with.hpp
new file mode 100644
index 00000000..f5eec324
--- /dev/null
+++ b/sprout/type_traits/is_swappable_with.hpp
@@ -0,0 +1,58 @@
+/*=============================================================================
+  Copyright (c) 2011-2016 Bolero MURAKAMI
+  https://github.com/bolero-MURAKAMI/Sprout
+
+  Distributed under the Boost Software License, Version 1.0. (See accompanying
+  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+=============================================================================*/
+#ifndef SPROUT_TYPE_TRAITS_IS_SWAPPABLE_WITH_HPP
+#define SPROUT_TYPE_TRAITS_IS_SWAPPABLE_WITH_HPP
+
+#include <utility>
+#include <sprout/config.hpp>
+#include <sprout/type_traits/integral_constant.hpp>
+#include <sprout/type_traits/identity.hpp>
+
+namespace sprout_swappable_detail {
+	using std::swap;
+
+	template<typename T, typename U>
+	struct is_swappable_with_test {
+	public:
+		template<
+			typename T1 = T, typename U1 = U,
+			typename = typename sprout::identity<decltype(swap(std::declval<T1>(), std::declval<U1>()))>::type,
+			typename = typename sprout::identity<decltype(swap(std::declval<U1>(), std::declval<T1>()))>::type
+		>
+		static sprout::true_type test(int);
+		static sprout::false_type test(...);
+	};
+#if defined(_MSC_VER) && (_MSC_VER > 1900)
+	template<typename T, typename U, typename Base_ = typename sprout::identity<decltype(sprout_swappable_detail::is_swappable_with_test<T, U>::test(0))>::type>
+	struct is_swappable_with
+		: public Base_
+	{};
+#else
+	template<typename T, typename U>
+	struct is_swappable_with
+		: public sprout::identity<decltype(sprout_swappable_detail::is_swappable_with_test<T, U>::test(0))>::type
+	{};
+#endif
+}	// namespace sprout_swappable_detail
+
+namespace sprout {
+	//
+	// is_swappable_with
+	//
+	template<typename T, typename U>
+	struct is_swappable_with
+		: public sprout_swappable_detail::is_swappable_with<T, U>
+	{};
+
+#if SPROUT_USE_VARIABLE_TEMPLATES
+	template<typename T, typename U>
+	SPROUT_STATIC_CONSTEXPR bool is_swappable_with_v = sprout::is_swappable_with<T>::value;
+#endif	// #if SPROUT_USE_VARIABLE_TEMPLATES
+}	// namespace sprout
+
+#endif	// #ifndef SPROUT_TYPE_TRAITS_IS_SWAPPABLE_WITH_HPP
diff --git a/sprout/type_traits/is_unsigned.hpp b/sprout/type_traits/is_unsigned.hpp
index 895631ff..0013e26b 100644
--- a/sprout/type_traits/is_unsigned.hpp
+++ b/sprout/type_traits/is_unsigned.hpp
@@ -27,7 +27,7 @@ namespace sprout {
 			: public sprout::detail::type_traits_wrapper<std::is_unsigned<T> >
 		{};
 	}	// namespace detail
-	template <typename T>
+	template<typename T>
 	struct is_unsigned
 		: public sprout::detail::is_unsigned_impl<T>
 	{};
diff --git a/sprout/type_traits/logical.hpp b/sprout/type_traits/logical.hpp
new file mode 100644
index 00000000..c3784d93
--- /dev/null
+++ b/sprout/type_traits/logical.hpp
@@ -0,0 +1,17 @@
+/*=============================================================================
+  Copyright (c) 2011-2016 Bolero MURAKAMI
+  https://github.com/bolero-MURAKAMI/Sprout
+
+  Distributed under the Boost Software License, Version 1.0. (See accompanying
+  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+=============================================================================*/
+#ifndef SPROUT_TYPE_TRAITS_LOGICAL_HPP
+#define SPROUT_TYPE_TRAITS_LOGICAL_HPP
+
+#include <sprout/config.hpp>
+// logical operator traits:
+#include <sprout/type_traits/conjunction.hpp>
+#include <sprout/type_traits/disjunction.hpp>
+#include <sprout/type_traits/negation.hpp>
+
+#endif	// #ifndef SPROUT_TYPE_TRAITS_LOGICAL_HPP
diff --git a/sprout/type_traits/negation.hpp b/sprout/type_traits/negation.hpp
new file mode 100644
index 00000000..46541de3
--- /dev/null
+++ b/sprout/type_traits/negation.hpp
@@ -0,0 +1,29 @@
+/*=============================================================================
+  Copyright (c) 2011-2016 Bolero MURAKAMI
+  https://github.com/bolero-MURAKAMI/Sprout
+
+  Distributed under the Boost Software License, Version 1.0. (See accompanying
+  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+=============================================================================*/
+#ifndef SPROUT_TYPE_TRAITS_NEGATION_HPP
+#define SPROUT_TYPE_TRAITS_NEGATION_HPP
+
+#include <sprout/config.hpp>
+#include <sprout/type_traits/integral_constant.hpp>
+
+namespace sprout {
+	//
+	// negation
+	//
+	template<typename T>
+	struct negation
+		: public sprout::bool_constant<!T::value>
+	{};
+
+#if SPROUT_USE_VARIABLE_TEMPLATES
+	template<typename T>
+	SPROUT_STATIC_CONSTEXPR bool negation_v = sprout::negation<T>::value;
+#endif	// #if SPROUT_USE_VARIABLE_TEMPLATES
+}	// namespace sprout
+
+#endif	// #ifndef SPROUT_TYPE_TRAITS_NEGATION_HPP
diff --git a/sprout/type_traits/property.hpp b/sprout/type_traits/property.hpp
index a0b931bc..a002c7cf 100644
--- a/sprout/type_traits/property.hpp
+++ b/sprout/type_traits/property.hpp
@@ -30,6 +30,8 @@
 #include <sprout/type_traits/is_assignable.hpp>
 #include <sprout/type_traits/is_copy_assignable.hpp>
 #include <sprout/type_traits/is_move_assignable.hpp>
+#include <sprout/type_traits/is_swappable_with.hpp>
+#include <sprout/type_traits/is_swappable.hpp>
 #include <sprout/type_traits/is_destructible.hpp>
 #include <sprout/type_traits/is_trivially_constructible.hpp>
 #include <sprout/type_traits/is_trivially_default_constructible.hpp>
@@ -46,6 +48,8 @@
 #include <sprout/type_traits/is_nothrow_assignable.hpp>
 #include <sprout/type_traits/is_nothrow_copy_assignable.hpp>
 #include <sprout/type_traits/is_nothrow_move_assignable.hpp>
+#include <sprout/type_traits/is_nothrow_swappable_with.hpp>
+#include <sprout/type_traits/is_nothrow_swappable.hpp>
 #include <sprout/type_traits/is_nothrow_destructible.hpp>
 #include <sprout/type_traits/has_virtual_destructor.hpp>
 
diff --git a/sprout/type_traits/std_type_traits.hpp b/sprout/type_traits/std_type_traits.hpp
index af91b744..1df5bcf5 100644
--- a/sprout/type_traits/std_type_traits.hpp
+++ b/sprout/type_traits/std_type_traits.hpp
@@ -21,5 +21,7 @@
 #include <sprout/type_traits/array_modification.hpp>
 #include <sprout/type_traits/pointer_modification.hpp>
 #include <sprout/type_traits/transformation.hpp>
+#include <sprout/type_traits/logical.hpp>
+#include <sprout/type_traits/voider.hpp>
 
 #endif	// #ifndef SPROUT_TYPE_TRAITS_STD_TYPE_TRAITS_HPP
diff --git a/sprout/type_traits/voider.hpp b/sprout/type_traits/voider.hpp
new file mode 100644
index 00000000..0db420f0
--- /dev/null
+++ b/sprout/type_traits/voider.hpp
@@ -0,0 +1,29 @@
+/*=============================================================================
+  Copyright (c) 2011-2016 Bolero MURAKAMI
+  https://github.com/bolero-MURAKAMI/Sprout
+
+  Distributed under the Boost Software License, Version 1.0. (See accompanying
+  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+=============================================================================*/
+#ifndef SPROUT_TYPE_TRAITS_VOIDER_HPP
+#define SPROUT_TYPE_TRAITS_VOIDER_HPP
+
+#include <sprout/config.hpp>
+
+namespace sprout {
+	//
+	// voider
+	//
+	template<typename...>
+	struct voider {
+	public:
+		typedef void type;
+	};
+
+#if SPROUT_USE_TEMPLATE_ALIASES
+	template<typename...>
+	using void_t = void;
+#endif	// #if SPROUT_USE_TEMPLATE_ALIASES
+}	// namespace sprout
+
+#endif	// #ifndef SPROUT_TYPE_TRAITS_VOIDER_HPP