From 4c2898345972bd6c44c6b55abb386af931cc8fb5 Mon Sep 17 00:00:00 2001
From: Nathan Ridge <zeratul976@hotmail.com>
Date: Tue, 20 Aug 2013 06:06:12 +0000
Subject: [PATCH] [range] Fixed a bug in join_iterator where joining a const
 range and a non-const range led to a compiler error (refs #8483).

[SVN r85400]
---
 include/boost/range/detail/join_iterator.hpp |  8 ++++++--
 test/join.cpp                                | 13 +++++++++++++
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/include/boost/range/detail/join_iterator.hpp b/include/boost/range/detail/join_iterator.hpp
index bbdeec7..70ecf65 100644
--- a/include/boost/range/detail/join_iterator.hpp
+++ b/include/boost/range/detail/join_iterator.hpp
@@ -143,8 +143,12 @@ template<typename Iterator1
                                     typename iterator_reference<Iterator2>::type
                                 >::type
                             >::value,
-                            typename add_const<
-                                typename iterator_reference<Iterator2>::type
+                            typename add_reference<
+                                typename add_const<
+                                    typename remove_reference<
+                                        typename iterator_reference<Iterator2>::type
+                                    >::type
+                                >::type
                             >::type,
                             typename iterator_reference<Iterator1>::type
                         >::type
diff --git a/test/join.cpp b/test/join.cpp
index 290e651..b30d060 100644
--- a/test/join.cpp
+++ b/test/join.cpp
@@ -257,6 +257,18 @@ namespace boost
             test_join_impl< std::vector<int>, std::deque<int>  >();
             test_join_impl< std::deque<int>,  std::vector<int> >();
         }
+        
+        void test_join_iterator_reference_type_constness_ticket8483()
+        {
+            // Just test that this compiles.
+            // Before the fix for bug 8483, the reference type of the joined
+            // range's iterator was incorrect ('int&' instead of 'const int&'),
+            // causing compiler errors.
+            const std::vector<int> v1;
+            std::vector<int> v2;
+            std::vector<int> joined;
+            boost::push_back(joined, join(v1, v2));
+        }
 
     }
 }
@@ -268,6 +280,7 @@ init_unit_test_suite(int argc, char* argv[])
         = BOOST_TEST_SUITE( "RangeTestSuite.adaptor.joined" );
 
     test->add( BOOST_TEST_CASE( &boost::join_test ) );
+    test->add( BOOST_TEST_CASE( &boost::test_join_iterator_reference_type_constness_ticket8483 ) );
 
     return test;
 }