diff --git a/include/boost/unordered/detail/fwd.hpp b/include/boost/unordered/detail/fwd.hpp
index c1c31ffc..ce1d5bd1 100644
--- a/include/boost/unordered/detail/fwd.hpp
+++ b/include/boost/unordered/detail/fwd.hpp
@@ -734,8 +734,18 @@ namespace boost { namespace unordered_detail {
     class iterator_access
     {
     public:
+        // Note: we access Iterator::base here, rather than in the function
+        // signature to work around a bug in the friend support of an
+        // early version of clang.
+
         template <class Iterator>
-        static BOOST_DEDUCED_TYPENAME Iterator::base const&
+        struct base
+        {
+            typedef BOOST_DEDUCED_TYPENAME Iterator::base type;
+        };
+    
+        template <class Iterator>
+        static BOOST_DEDUCED_TYPENAME base<Iterator>::type const&
             get(Iterator const& it)
         {
             return it.base_;