diff --git a/sprout/type_traits.hpp b/sprout/type_traits.hpp
index 75a1db41..7247a443 100644
--- a/sprout/type_traits.hpp
+++ b/sprout/type_traits.hpp
@@ -11,6 +11,7 @@
 #include <sprout/config.hpp>
 #include <sprout/type_traits/std.hpp>
 #include <sprout/type_traits/composite_modification.hpp>
+#include <sprout/type_traits/has_operator.hpp>
 #include <sprout/type_traits/introspection.hpp>
 
 #endif	// #ifndef SPROUT_TYPE_TRAITS_HPP
diff --git a/sprout/type_traits/composite_modification.hpp b/sprout/type_traits/composite_modification.hpp
index 8c5b09f4..76908f3a 100644
--- a/sprout/type_traits/composite_modification.hpp
+++ b/sprout/type_traits/composite_modification.hpp
@@ -16,5 +16,8 @@
 #include <sprout/type_traits/remove_shallow_volatile.hpp>
 #include <sprout/type_traits/remove_shallow_cv.hpp>
 #include <sprout/type_traits/remove_shallow_cvref.hpp>
+#include <sprout/type_traits/copy_const.hpp>
+#include <sprout/type_traits/copy_volatile.hpp>
+#include <sprout/type_traits/copy_cv.hpp>
 
 #endif	// #ifndef SPROUT_TYPE_TRAITS_COMPOSITE_MODIFICATION_HPP
diff --git a/sprout/type_traits/copy_const.hpp b/sprout/type_traits/copy_const.hpp
new file mode 100644
index 00000000..41d20f1e
--- /dev/null
+++ b/sprout/type_traits/copy_const.hpp
@@ -0,0 +1,34 @@
+/*=============================================================================
+  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_COPY_CONST_HPP
+#define SPROUT_TYPE_TRAITS_COPY_CONST_HPP
+
+#include <type_traits>
+#include <sprout/config.hpp>
+#include <sprout/type_traits/identity.hpp>
+
+namespace sprout {
+	//
+	// copy_const
+	//
+	template<typename T, typename U>
+	struct copy_const
+		: public sprout::identity<T>
+	{};
+	template<typename T, typename U>
+	struct copy_const<T, U volatile>
+		: public std::add_volatile<T>
+	{};
+
+#if SPROUT_USE_TEMPLATE_ALIASES
+	template<typename T, typename U>
+	using copy_const_t = typename sprout::copy_const<T, U>::type;
+#endif	// #if SPROUT_USE_TEMPLATE_ALIASES
+}	// namespace sprout
+
+#endif	// #ifndef SPROUT_TYPE_TRAITS_COPY_CONST_HPP
diff --git a/sprout/type_traits/copy_cv.hpp b/sprout/type_traits/copy_cv.hpp
new file mode 100644
index 00000000..0ee05dcf
--- /dev/null
+++ b/sprout/type_traits/copy_cv.hpp
@@ -0,0 +1,42 @@
+/*=============================================================================
+  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_COPY_CV_HPP
+#define SPROUT_TYPE_TRAITS_COPY_CV_HPP
+
+#include <type_traits>
+#include <sprout/config.hpp>
+#include <sprout/type_traits/identity.hpp>
+
+namespace sprout {
+	//
+	// copy_cv
+	//
+	template<typename T, typename U>
+	struct copy_cv
+		: public sprout::identity<T>
+	{};
+	template<typename T, typename U>
+	struct copy_cv<T, U const>
+		: public std::add_const<T>
+	{};
+	template<typename T, typename U>
+	struct copy_cv<T, U volatile>
+		: public std::add_volatile<T>
+	{};
+	template<typename T, typename U>
+	struct copy_cv<T, U const volatile>
+		: public std::add_cv<T>
+	{};
+
+#if SPROUT_USE_TEMPLATE_ALIASES
+	template<typename T, typename U>
+	using copy_cv_t = typename sprout::copy_cv<T, U>::type;
+#endif	// #if SPROUT_USE_TEMPLATE_ALIASES
+}	// namespace sprout
+
+#endif	// #ifndef SPROUT_TYPE_TRAITS_COPY_CV_HPP
diff --git a/sprout/type_traits/copy_volatile.hpp b/sprout/type_traits/copy_volatile.hpp
new file mode 100644
index 00000000..05ea3d25
--- /dev/null
+++ b/sprout/type_traits/copy_volatile.hpp
@@ -0,0 +1,34 @@
+/*=============================================================================
+  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_COPY_VOLATILE_HPP
+#define SPROUT_TYPE_TRAITS_COPY_VOLATILE_HPP
+
+#include <type_traits>
+#include <sprout/config.hpp>
+#include <sprout/type_traits/identity.hpp>
+
+namespace sprout {
+	//
+	// copy_volatile
+	//
+	template<typename T, typename U>
+	struct copy_volatile
+		: public sprout::identity<T>
+	{};
+	template<typename T, typename U>
+	struct copy_volatile<T, U volatile>
+		: public std::add_volatile<T>
+	{};
+
+#if SPROUT_USE_TEMPLATE_ALIASES
+	template<typename T, typename U>
+	using copy_volatile_t = typename sprout::copy_volatile<T, U>::type;
+#endif	// #if SPROUT_USE_TEMPLATE_ALIASES
+}	// namespace sprout
+
+#endif	// #ifndef SPROUT_TYPE_TRAITS_COPY_VOLATILE_HPP
diff --git a/sprout/type_traits/detail/has_binary_op.hpp b/sprout/type_traits/detail/has_binary_op.hpp
new file mode 100644
index 00000000..c988c58e
--- /dev/null
+++ b/sprout/type_traits/detail/has_binary_op.hpp
@@ -0,0 +1,60 @@
+/*=============================================================================
+  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_DETAIL_HAS_BINARY_OP_HPP
+#define SPROUT_TYPE_TRAITS_DETAIL_HAS_BINARY_OP_HPP
+
+#include <utility>
+#include <type_traits>
+#include <sprout/config.hpp>
+#include <sprout/type_traits/integral_constant.hpp>
+#include <sprout/type_traits/identity.hpp>
+#include <sprout/type_traits/dont_care.hpp>
+#include <sprout/preprocessor/cat.hpp>
+
+#define SPROUT_DETAIL_HAS_BINARY_OP_DECL(OP_NAME, OP) \
+	template<typename T1, typename T2, typename R> \
+	struct SPROUT_PP_CAT(sprout_detail_has_, SPROUT_PP_CAT(OP_NAME, _test)) { \
+	public: \
+		template< \
+			typename U1 = T1, typename U2 = T2, \
+			typename Result = sprout::bool_constant<std::is_convertible<typename sprout::identity<decltype(std::declval<U1>() OP std::declval<U2>())>::type, R>::value> \
+		> \
+		static Result test(int); \
+		static sprout::false_type test(...); \
+	}; \
+	template<typename T1, typename T2> \
+	struct SPROUT_PP_CAT(sprout_detail_has_, SPROUT_PP_CAT(OP_NAME, _test))<T1, T2, sprout::dont_care> { \
+	public: \
+		template< \
+			typename U1 = T1, typename U2 = T2, \
+			typename typename sprout::identity<decltype(std::declval<U1>() OP std::declval<U2>())>::type \
+		> \
+		static sprout::true_type test(int); \
+		static sprout::false_type test(...); \
+	}; \
+	SPROUT_DETAIL_HAS_BINARY_OP_DECL_IMPL(OP_NAME); \
+	template<typename T, typename U, typename R = sprout::dont_care> \
+	struct SPROUT_PP_CAT(has_, OP_NAME) \
+		: public SPROUT_PP_CAT(sprout_detail_has_, OP_NAME)<T, U, R> \
+	{}
+
+#if defined(_MSC_VER) && (_MSC_VER > 1900)
+#	define SPROUT_DETAIL_HAS_BINARY_OP_DECL_IMPL(OP_NAME) \
+		template<typename T, typename U, typename R, typename Base_ = typename sprout::identity<decltype(SPROUT_PP_CAT(sprout_detail_has_, OP_NAME)<T, U, R>::test(0))>::type> \
+		struct SPROUT_PP_CAT(sprout_detail_has_, OP_NAME) \
+			: public Base_ \
+		{}
+#else
+#	define SPROUT_DETAIL_HAS_BINARY_OP_DECL_IMPL(OP_NAME) \
+		template<typename T, typename U, typename R> \
+		struct SPROUT_PP_CAT(sprout_detail_has_, OP_NAME) \
+			: public sprout::identity<decltype(SPROUT_PP_CAT(sprout_detail_has_, OP_NAME)<T, U, R>::test(0))>::type \
+		{}
+#endif
+
+#endif	// #ifndef SPROUT_TYPE_TRAITS_DETAIL_HAS_BINARY_OP_HPP
diff --git a/sprout/type_traits/detail/has_post_unary_op.hpp b/sprout/type_traits/detail/has_post_unary_op.hpp
new file mode 100644
index 00000000..dd1761b9
--- /dev/null
+++ b/sprout/type_traits/detail/has_post_unary_op.hpp
@@ -0,0 +1,60 @@
+/*=============================================================================
+  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_DETAIL_HAS_POST_UNARY_OP_HPP
+#define SPROUT_TYPE_TRAITS_DETAIL_HAS_POST_UNARY_OP_HPP
+
+#include <utility>
+#include <type_traits>
+#include <sprout/config.hpp>
+#include <sprout/type_traits/integral_constant.hpp>
+#include <sprout/type_traits/identity.hpp>
+#include <sprout/type_traits/dont_care.hpp>
+#include <sprout/preprocessor/cat.hpp>
+
+#define SPROUT_DETAIL_HAS_POST_UNARY_OP_DECL(OP_NAME, OP) \
+	template<typename T, typename R> \
+	struct SPROUT_PP_CAT(sprout_detail_has_, SPROUT_PP_CAT(OP_NAME, _test)) { \
+	public: \
+		template< \
+			typename U = T, \
+			typename Result = sprout::bool_constant<std::is_convertible<typename sprout::identity<decltype(std::declval<U>() OP)>::type, R>::value> \
+		> \
+		static Result test(int); \
+		static sprout::false_type test(...); \
+	}; \
+	template<typename T> \
+	struct SPROUT_PP_CAT(sprout_detail_has_, SPROUT_PP_CAT(OP_NAME, _test))<T, sprout::dont_care> { \
+	public: \
+		template< \
+			typename U = T, \
+			typename typename sprout::identity<decltype(std::declval<U>() OP)>::type \
+		> \
+		static sprout::true_type test(int); \
+		static sprout::false_type test(...); \
+	}; \
+	SPROUT_DETAIL_HAS_POST_UNARY_OP_DECL_IMPL(OP_NAME); \
+	template<typename T, typename R = sprout::dont_care> \
+	struct SPROUT_PP_CAT(has_, OP_NAME) \
+		: public SPROUT_PP_CAT(sprout_detail_has_, OP_NAME)<T, R> \
+	{}
+
+#if defined(_MSC_VER) && (_MSC_VER > 1900)
+#	define SPROUT_DETAIL_HAS_POST_UNARY_OP_DECL_IMPL(OP_NAME) \
+		template<typename T, typename R, typename Base_ = typename sprout::identity<decltype(SPROUT_PP_CAT(sprout_detail_has_, OP_NAME)<T, R>::test(0))>::type> \
+		struct SPROUT_PP_CAT(sprout_detail_has_, OP_NAME) \
+			: public Base_ \
+		{}
+#else
+#	define SPROUT_DETAIL_HAS_POST_UNARY_OP_DECL_IMPL(OP_NAME) \
+		template<typename T, typename R> \
+		struct SPROUT_PP_CAT(sprout_detail_has_, OP_NAME) \
+			: public sprout::identity<decltype(SPROUT_PP_CAT(sprout_detail_has_, OP_NAME)<T, R>::test(0))>::type \
+		{}
+#endif
+
+#endif	// #ifndef SPROUT_TYPE_TRAITS_DETAIL_HAS_POST_UNARY_OP_HPP
diff --git a/sprout/type_traits/detail/has_pre_unary_op.hpp b/sprout/type_traits/detail/has_pre_unary_op.hpp
new file mode 100644
index 00000000..05b570f0
--- /dev/null
+++ b/sprout/type_traits/detail/has_pre_unary_op.hpp
@@ -0,0 +1,60 @@
+/*=============================================================================
+  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_DETAIL_HAS_PRE_UNARY_OP_HPP
+#define SPROUT_TYPE_TRAITS_DETAIL_HAS_PRE_UNARY_OP_HPP
+
+#include <utility>
+#include <type_traits>
+#include <sprout/config.hpp>
+#include <sprout/type_traits/integral_constant.hpp>
+#include <sprout/type_traits/identity.hpp>
+#include <sprout/type_traits/dont_care.hpp>
+#include <sprout/preprocessor/cat.hpp>
+
+#define SPROUT_DETAIL_HAS_PRE_UNARY_OP_DECL(OP_NAME, OP) \
+	template<typename T, typename R> \
+	struct SPROUT_PP_CAT(sprout_detail_has_, SPROUT_PP_CAT(OP_NAME, _test)) { \
+	public: \
+		template< \
+			typename U = T, \
+			typename Result = sprout::bool_constant<std::is_convertible<typename sprout::identity<decltype(OP std::declval<U>())>::type, R>::value> \
+		> \
+		static Result test(int); \
+		static sprout::false_type test(...); \
+	}; \
+	template<typename T> \
+	struct SPROUT_PP_CAT(sprout_detail_has_, SPROUT_PP_CAT(OP_NAME, _test))<T, sprout::dont_care> { \
+	public: \
+		template< \
+			typename U = T, \
+			typename typename sprout::identity<decltype(OP std::declval<U>())>::type \
+		> \
+		static sprout::true_type test(int); \
+		static sprout::false_type test(...); \
+	}; \
+	SPROUT_DETAIL_HAS_PRE_UNARY_OP_DECL_IMPL(OP_NAME); \
+	template<typename T, typename R = sprout::dont_care> \
+	struct SPROUT_PP_CAT(has_, OP_NAME) \
+		: public SPROUT_PP_CAT(sprout_detail_has_, OP_NAME)<T, R> \
+	{}
+
+#if defined(_MSC_VER) && (_MSC_VER > 1900)
+#	define SPROUT_DETAIL_HAS_PRE_UNARY_OP_DECL_IMPL(OP_NAME) \
+		template<typename T, typename R, typename Base_ = typename sprout::identity<decltype(SPROUT_PP_CAT(sprout_detail_has_, OP_NAME)<T, R>::test(0))>::type> \
+		struct SPROUT_PP_CAT(sprout_detail_has_, OP_NAME) \
+			: public Base_ \
+		{}
+#else
+#	define SPROUT_DETAIL_HAS_PRE_UNARY_OP_DECL_IMPL(OP_NAME) \
+		template<typename T, typename R> \
+		struct SPROUT_PP_CAT(sprout_detail_has_, OP_NAME) \
+			: public sprout::identity<decltype(SPROUT_PP_CAT(sprout_detail_has_, OP_NAME)<T, R>::test(0))>::type \
+		{}
+#endif
+
+#endif	// #ifndef SPROUT_TYPE_TRAITS_DETAIL_HAS_PRE_UNARY_OP_HPP
diff --git a/sprout/type_traits/dont_care.hpp b/sprout/type_traits/dont_care.hpp
new file mode 100644
index 00000000..a225f811
--- /dev/null
+++ b/sprout/type_traits/dont_care.hpp
@@ -0,0 +1,20 @@
+/*=============================================================================
+  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_DONT_CARE_HPP
+#define SPROUT_TYPE_TRAITS_DONT_CARE_HPP
+
+#include <sprout/config.hpp>
+
+namespace sprout {
+	//
+	// dont_care
+	//
+	struct dont_care {};
+}	// namespace sprout
+
+#endif	// #ifndef SPROUT_TYPE_TRAITS_DONT_CARE_HPP
diff --git a/sprout/type_traits/enabler_if.hpp b/sprout/type_traits/enabler_if.hpp
index de096f5a..f65ec54f 100644
--- a/sprout/type_traits/enabler_if.hpp
+++ b/sprout/type_traits/enabler_if.hpp
@@ -25,11 +25,7 @@ namespace sprout {
 	//
 	template<bool C>
 	class enabler_if
-#if defined(__INTEL_COMPILER) || defined(__ICL) || defined(__ICC) || defined(__ECC)
 		: public std::enable_if<C, sprout::enabler_t>
-#else
-		: public std::enable_if<C, sprout::enabler_t&>
-#endif
 	{};
 	//
 	// disabler_if
diff --git a/sprout/type_traits/has_assign.hpp b/sprout/type_traits/has_assign.hpp
new file mode 100644
index 00000000..41fd3ac4
--- /dev/null
+++ b/sprout/type_traits/has_assign.hpp
@@ -0,0 +1,28 @@
+/*=============================================================================
+  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_HAS_ASSIGN_HPP
+#define SPROUT_TYPE_TRAITS_HAS_ASSIGN_HPP
+
+#include <type_traits>
+#include <sprout/config.hpp>
+#include <sprout/type_traits/dont_care.hpp>
+#include <sprout/type_traits/detail/has_binary_op.hpp>
+
+namespace sprout {
+	//
+	// has_assign
+	//
+	SPROUT_DETAIL_HAS_BINARY_OP_DECL(has_assign, =);
+
+#if SPROUT_USE_VARIABLE_TEMPLATES
+	template<typename T, typename U, typename R = sprout::dont_care>
+	SPROUT_STATIC_CONSTEXPR bool has_assign_v = sprout::has_assign<T, U, R>::value;
+#endif	// #if SPROUT_USE_VARIABLE_TEMPLATES
+}	// namespace sprout
+
+#endif	// #ifndef SPROUT_TYPE_TRAITS_HAS_ASSIGN_HPP
diff --git a/sprout/type_traits/has_operator.hpp b/sprout/type_traits/has_operator.hpp
new file mode 100644
index 00000000..9e6d66df
--- /dev/null
+++ b/sprout/type_traits/has_operator.hpp
@@ -0,0 +1,14 @@
+/*=============================================================================
+  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>
+#include <sprout/type_traits/has_assign.hpp>
+
+#endif	// #ifndef SPROUT_TYPE_TRAITS_LOGICAL_HPP