From 153fd7f474861eb0196d2a5e8e10f4c8627b99fa Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ion=20Gazta=C3=B1aga?= <igaztanaga@gmail.com>
Date: Sat, 25 Jun 2016 11:04:55 +0200
Subject: [PATCH] Add more is_class, is_class_or_union, is_enum specialization
 to pair to allow recursive containers and type traits intrinsics

---
 include/boost/container/detail/pair.hpp | 41 +++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/include/boost/container/detail/pair.hpp b/include/boost/container/detail/pair.hpp
index 134760e..f239b69 100644
--- a/include/boost/container/detail/pair.hpp
+++ b/include/boost/container/detail/pair.hpp
@@ -283,6 +283,12 @@ struct is_enum< ::boost::container::container_detail::pair<T, U> >
    static const bool value = false;
 };
 
+template<class T, class U>
+struct is_enum< ::std::pair<T, U> >
+{
+   static const bool value = false;
+};
+
 template <class T>
 struct is_class;
 
@@ -325,8 +331,43 @@ struct is_class_or_union< std::pair<T1, T2> >
    static const bool value = true;
 };
 
+template<class T>
+struct is_union;
 
+template <class T1, class T2>
+struct is_union< ::boost::container::container_detail::pair<T1, T2> >
+//This specialization is needed to avoid instantiation of pair in
+//is_class, and allow recursive maps.
+{
+   static const bool value = false;
+};
 
+template <class T1, class T2>
+struct is_union< std::pair<T1, T2> >
+//This specialization is needed to avoid instantiation of pair in
+//is_class, and allow recursive maps.
+{
+   static const bool value = false;
+};
+
+template<class T>
+struct is_class;
+
+template <class T1, class T2>
+struct is_class< ::boost::container::container_detail::pair<T1, T2> >
+//This specialization is needed to avoid instantiation of pair in
+//is_class, and allow recursive maps.
+{
+   static const bool value = true;
+};
+
+template <class T1, class T2>
+struct is_class< std::pair<T1, T2> >
+//This specialization is needed to avoid instantiation of pair in
+//is_class, and allow recursive maps.
+{
+   static const bool value = true;
+};
 
 }  //namespace move_detail{