Boost.Range Fix for trac issue #3110 - Multi_array and iterator_range interaction.

This has been fixed by reusing the well proven iterator_facade operator[] mechanism.

[SVN r61029]

include/boost/range/iterator_range_core.hpp

@@ -20,6 +20,7 @@
 
 #include <boost/assert.hpp>
 #include <boost/iterator/iterator_traits.hpp>
+#include <boost/iterator/iterator_facade.hpp>
 #include <boost/type_traits/is_abstract.hpp>
 #include <boost/range/functions.hpp>
 #include <boost/range/iterator.hpp>
@@ -45,7 +46,7 @@ namespace boost
         // The functions adl_begin and adl_end are implemented in a separate
         // class for gcc-2.9x
         //
-        template<typename IteratorT>
+        template<class IteratorT>
         struct iterator_range_impl {
             template< class ForwardRange >
             static IteratorT adl_begin( ForwardRange& r )
@@ -101,7 +102,7 @@ namespace boost
             It provides a collection interface,
             so it is possible to pass an instance to an algorithm requiring a collection as an input.
         */
-        template<typename IteratorT> 
+        template<class IteratorT>
         class iterator_range
         {
         protected: // Used by sub_range
@@ -288,10 +289,13 @@ namespace boost
                return *--last;
            }
 
-           reference operator[]( difference_type at ) const
+           BOOST_DEDUCED_TYPENAME boost::detail::operator_brackets_result<iterator, value_type, reference>::type
+           operator[]( difference_type at ) const
            {
                BOOST_ASSERT( at >= 0 && at < size() );
-               return m_Begin[at];
+
+               typedef boost::detail::use_operator_brackets_proxy<value_type,reference> use_proxy;
+               return boost::detail::make_operator_brackets_result<iterator>(m_Begin + at, use_proxy());
            }
 
            //