trac 7376 - join iterator reference type.

include/boost/range/detail/join_iterator.hpp

@@ -9,6 +9,9 @@
 // aschoedl contributed an improvement to the determination
 // of the Reference type parameter.
 //
+// Leonid Gershanovich reported Trac ticket 7376 about the dereference operator
+// requiring identical reference types due to using the ternary if.
+//
 // For more information, see http://www.boost.org/libs/range/
 //
 #ifndef BOOST_RANGE_DETAIL_JOIN_ITERATOR_HPP_INCLUDED