core: Deprecate struct TypeTraits

CHANGES.md

@@ -24,6 +24,7 @@ Changes from ns-3.42 to ns-3-dev
 
 ### Changes to existing API
 
+* (core) Deprecated struct `TypeTraits`. Functionality provided by the standard library header `<type_traits>` should be used instead.
 * (lr-wpan) Attribute `macBeaconPayload` in `MacPibAttributes` is now a std::vector<uint8_t> instead of a packet pointer.
 * (lr-wpan) Removes the word `address` from the MAC address prefix when `LOG_PREFIX_FUNC` is used.
 * (lr-wpan) Removes the word `address` from the CSMA-CA logs prefix when `LOG_PREFIX_FUNC` is used.

src/core/model/type-traits.h

@@ -19,6 +19,7 @@
 #ifndef TYPE_TRAITS_H
 #define TYPE_TRAITS_H
 
+#include "deprecated.h"
 #include "ptr.h"
 
 /**
@@ -36,7 +37,7 @@ namespace ns3
  *  \tparam T \deduced The type to inspect.
  */
 template <typename T>
-struct TypeTraits
+struct NS_DEPRECATED_3_43("Use functions provided by #include <type_traits>") TypeTraits
 {
   private:
     /** Null value type traits. */