core, test: Use type trait functions from std header

src/core/model/attribute-accessor-helper.h

@@ -117,7 +117,7 @@ inline Ptr<const AttributeAccessor> MakeAccessorHelper(T1 a1, T2 a2);
  *  Implementation of the templates declared above.
  ***************************************************************/
 
-#include "type-traits.h"
+#include <type_traits>
 
 namespace ns3
 {
@@ -133,7 +133,7 @@ template <typename T>
 struct AccessorTrait
 {
     /** The non-const, non reference type. */
-    typedef typename TypeTraits<typename TypeTraits<T>::ReferencedType>::NonConstType Result;
+    using Result = std::remove_cvref_t<T>;
 };
 
 /**

src/test/traced/traced-callback-typedef-test-suite.cc

@@ -26,6 +26,7 @@
 #include <set>
 #include <sstream>
 #include <string>
+#include <type_traits>
 // Ipv6L3Protocol, Ipv6PacketProbe
 #include "ns3/lr-wpan-mac.h"      // LrWpanMac
 #include "ns3/lte-module.h"       // PhyReceptionStatParameters,
@@ -282,7 +283,7 @@ class TracedCallbackTypedefTestCase::Checker : public Object
     ~Checker() override{};
 
     /// Arguments of the TracedCallback.
-    std::tuple<typename TypeTraits<Ts>::BaseType...> m_items;
+    std::tuple<std::remove_pointer_t<std::remove_cvref_t<Ts>>...> m_items;
 
     /// Number of arguments of the TracedCallback.
     const std::size_t m_nItems = sizeof...(Ts);