Index: boost/iterator/transform_iterator.hpp
===================================================================
--- boost/iterator/transform_iterator.hpp	(revision 68460)
+++ boost/iterator/transform_iterator.hpp	(working copy)
@@ -46,7 +46,7 @@
         // the function.
         typedef typename ia_dflt_help<
             Reference
-          , result_of<UnaryFunc(typename std::iterator_traits<Iterator>::reference)>
+          , result_of<const UnaryFunc(typename std::iterator_traits<Iterator>::reference)>
         >::type reference;
 
         // To get the default for Value: remove any reference on the