updated functionality in type utility file

include/ck/utility/type.hpp

@@ -68,7 +68,6 @@ struct remove_reference<T&&>
 {
     typedef T type;
 };
-
 template <class T>
 struct remove_pointer
 {
@@ -94,33 +93,62 @@ struct remove_pointer<T* const volatile>
 {
     typedef T type;
 };
-template <class T>
-struct remove_const
-{
-    typedef T type;
-};
-template <class T>
-struct remove_const<const T>
-{
-    typedef T type;
-};
 
 template <typename T>
 constexpr T&& forward(typename remove_reference<T>::type& t_) noexcept
 {
     return static_cast<T&&>(t_);
 }
-
 template <typename T>
 constexpr T&& forward(typename remove_reference<T>::type&& t_) noexcept
 {
     return static_cast<T&&>(t_);
 }
 
+template <class T>
+struct is_const : public integral_constant<bool, false>
+{
+};
+template <class T>
+struct is_const<const T> : public integral_constant<bool, true>
+{
+};
+template <class T>
+inline constexpr bool is_const_v = is_const<T>::value;
+
 template <typename T>
-T&& declval() noexcept;
+inline constexpr bool is_reference_v = is_reference<T>::value;
+
+template <class T>
+struct remove_const
+{
+    typedef T type;
+};
+template <class T>
+struct remove_const<const T>
+{
+    typedef T type;
+};
+template <class T>
+using remove_const_t = typename remove_const<T>::type;
+template <class T>
+inline constexpr bool is_class_v = is_class<T>::value;
+
+template <class T>
+inline constexpr bool is_trivially_copyable_v = is_trivially_copyable<T>::value;
+// template <typename T>
+// T&& declval() noexcept;
+
+template <class T, class U = T&&>
+U private_declval(int);
+
+template <class T>
+T private_declval(long);
+
+template <class T>
+auto declval() noexcept -> decltype(private_declval<T>(0));
 
-template <typename... Ts>
+template <class...>
 using void_t = void;
 #else
 #include <utility>
@@ -129,9 +157,13 @@ using std::declval;
 using std::forward;
 using std::is_base_of;
 using std::is_class;
+using std::is_class_v;
+using std::is_const_v;
 using std::is_pointer;
 using std::is_reference;
+using std::is_reference_v;
 using std::is_trivially_copyable;
+using std::is_trivially_copyable_v;
 using std::is_unsigned;
 using std::remove_const;
 using std::remove_cv;
@@ -150,16 +182,6 @@ struct is_same<X, X> : public integral_constant<bool, true>
 {
 };
 
-template <typename X>
-struct is_const : public integral_constant<bool, false>
-{
-};
-
-template <typename X>
-struct is_const<const X> : public integral_constant<bool, true>
-{
-};
-
 template <typename X>
 struct is_floating_point : public integral_constant<bool, false>
 {
@@ -174,7 +196,6 @@ template <>
 struct is_floating_point<double> : public integral_constant<bool, true>
 {
 };
-
 template <>
 struct is_floating_point<long double> : public integral_constant<bool, true>
 {
@@ -209,7 +230,6 @@ template <>
 struct is_integral<short> : public integral_constant<bool, true>
 {
 };
-
 template <>
 struct is_integral<unsigned short> : public integral_constant<bool, true>
 {
@@ -244,7 +264,6 @@ template <>
 struct is_integral<wchar_t> : public integral_constant<bool, true>
 {
 };
-
 template <>
 struct is_integral<char16_t> : public integral_constant<bool, true>
 {
@@ -260,15 +279,9 @@ struct is_integral<bool> : public integral_constant<bool, true>
 {
 };
 
-template <typename T>
-inline constexpr bool is_reference_v = is_reference<T>::value;
-
 template <typename X, typename Y>
 inline constexpr bool is_same_v = is_same<X, Y>::value;
 
-template <typename X>
-inline constexpr bool is_const_v = is_const<X>::value;
-
 template <typename X, typename Y>
 inline constexpr bool is_base_of_v = is_base_of<X, Y>::value;
 
@@ -283,16 +296,12 @@ using remove_reference_t = typename remove_reference<T>::type;
 
 template <typename T>
 using remove_cv_t = typename remove_cv<T>::type;
-
 template <typename T>
 using remove_cvref_t = remove_cv_t<remove_reference_t<T>>;
 
 template <typename T>
 using remove_pointer_t = typename remove_pointer<T>::type;
 
-template <typename T>
-using remove_const_t = typename remove_const<T>::type;
-
 template <typename T>
 inline constexpr bool is_pointer_v = is_pointer<T>::value;