From 5e45f3d0ff50a3f5ca29c433ba2b59c74c1a44fe Mon Sep 17 00:00:00 2001
From: Louis Dionne <ldionne.2@gmail.com>
Date: Mon, 14 Dec 2015 13:29:26 -0500
Subject: [PATCH] Teach Hana how to forward declare reference_wrapper on
 Windows

---
 include/boost/hana/detail/as_container_element.hpp | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/include/boost/hana/detail/as_container_element.hpp b/include/boost/hana/detail/as_container_element.hpp
index 0ee8a30e08..e493414112 100644
--- a/include/boost/hana/detail/as_container_element.hpp
+++ b/include/boost/hana/detail/as_container_element.hpp
@@ -37,6 +37,13 @@ Distributed under the Boost Software License, Version 1.0.
     _GLIBCXX_END_NAMESPACE_VERSION
     }
 
+#elif defined(BOOST_HANA_CONFIG_LIBMSVCCXX)
+
+    namespace std {
+        template<class _Ty>
+        class reference_wrapper;
+    }
+
 #else
 
 #   error "Hana must be taught how to forward declare std::reference_wrapper for your standard library"