Added a test for compatibility of boost::distance between Range and Iterator.

This functionality is used in core Boost components, so it is preferable
to test it in Boost.Iterator, even if it's already tested in Boost.Range,
to discover problems as early as possible.

The test verifies that boost::distance implemented in Boost.Range can invoke
boost::distance in Boost.Iterator (i.e. the function lookup succeeds).

include/boost/iterator/advance.hpp

@@ -77,7 +77,7 @@ namespace iterators {
 
 } // namespace iterators
 
-using iterators::advance;
+using namespace iterators::advance_adl_barrier;
 
 } // namespace boost
 

include/boost/iterator/distance.hpp

@@ -58,7 +58,7 @@ namespace iterators {
 
 } // namespace iterators
 
-using iterators::distance;
+using namespace iterators::distance_adl_barrier;
 
 } // namespace boost
 

include/boost/iterator/iterator_archetypes.hpp

@@ -426,15 +426,16 @@ namespace detail
       >::type iterator_category;
 
       // Needed for some broken libraries (see below)
-      typedef boost::iterator<
-          iterator_category
-        , Value
-        , typename traversal_archetype_base<
+      struct workaround_iterator_base
+      {
+        typedef typename iterator_archetype_base::iterator_category iterator_category;
+        typedef Value value_type;
+        typedef typename traversal_archetype_base<
               Value, AccessCategory, TraversalCategory
-          >::difference_type
-        , typename access::pointer
-        , typename access::reference
-      > workaround_iterator_base;
+          >::difference_type difference_type;
+        typedef typename access::pointer pointer;
+        typedef typename access::reference reference;
+      };
   };
 }
 

test/Jamfile.v2

@@ -59,6 +59,8 @@ test-suite iterator
     [ run next_prior_test.cpp ]
     [ run advance_test.cpp ]
     [ run distance_test.cpp ]
+    [ compile adl_test.cpp ]
+    [ compile range_distance_compat_test.cpp ]
 
     [ run shared_iterator_test.cpp ]
 ;

test/adl_test.cpp

@@ -0,0 +1,25 @@
+// Copyright (C) 2017 Michel Morin.
+//
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#include <vector>
+#include <boost/array.hpp>
+#include <boost/iterator/advance.hpp>
+#include <boost/iterator/distance.hpp>
+
+int main()
+{
+    // Test that boost::advance/distance are not found by ADL.
+    // (https://github.com/boostorg/iterator/issues/43)
+
+    typedef boost::array<int, 1> boost_type;
+    std::vector<boost_type> std_boost(2);
+    std::vector<boost_type>::iterator it = std_boost.begin();
+
+    advance(it, 2);
+    (void)distance(it, it);
+
+    return 0;
+}

test/concept_tests.cpp

@@ -16,8 +16,13 @@ struct new_random_access
 {};
 
 struct new_iterator
-  : public std::iterator< new_random_access, int >
 {
+  typedef new_random_access iterator_category;
+  typedef int value_type;
+  typedef std::ptrdiff_t difference_type;
+  typedef int* pointer;
+  typedef int& reference;
+
   int& operator*() const { return *m_x; }
   new_iterator& operator++() { return *this; }
   new_iterator operator++(int) { return *this; }
@@ -36,8 +41,13 @@ struct new_iterator
 new_iterator operator+(std::ptrdiff_t, new_iterator x) { return x; }
 
 struct old_iterator
-  : public std::iterator<std::random_access_iterator_tag, int>
 {
+  typedef std::random_access_iterator_tag iterator_category;
+  typedef int value_type;
+  typedef std::ptrdiff_t difference_type;
+  typedef int* pointer;
+  typedef int& reference;
+
   int& operator*() const { return *m_x; }
   old_iterator& operator++() { return *this; }
   old_iterator operator++(int) { return *this; }

test/is_lvalue_iterator.cpp

@@ -5,10 +5,10 @@
 #include <deque>
 #include <iterator>
 #include <iostream>
+#include <cstddef> // std::ptrdiff_t
 #include <boost/static_assert.hpp>
 #include <boost/noncopyable.hpp>
 #include <boost/iterator/is_lvalue_iterator.hpp>
-#include <boost/iterator.hpp>
 
 // Last, for BOOST_NO_LVALUE_RETURN_DETECTION
 #include <boost/iterator/detail/config_def.hpp>
@@ -20,29 +20,36 @@ struct v
 };
 
 
-struct value_iterator : boost::iterator<std::input_iterator_tag,v>
+struct value_iterator
 {
+    typedef std::input_iterator_tag iterator_category;
+    typedef v value_type;
+    typedef std::ptrdiff_t difference_type;
+    typedef v* pointer;
+    typedef v& reference;
+
     v operator*() const;
 };
 
-struct noncopyable_iterator : boost::iterator<std::forward_iterator_tag,boost::noncopyable>
+struct noncopyable_iterator
 {
+    typedef std::forward_iterator_tag iterator_category;
+    typedef boost::noncopyable value_type;
+    typedef std::ptrdiff_t difference_type;
+    typedef boost::noncopyable* pointer;
+    typedef boost::noncopyable& reference;
+	
     boost::noncopyable const& operator*() const;
 };
 
 template <class T>
 struct proxy_iterator
-  : boost::iterator<std::output_iterator_tag,T>
 {
     typedef T value_type;
-    
-#if BOOST_WORKAROUND(__GNUC__, == 2)
-    typedef boost::iterator<std::input_iterator_tag,value_type> base;
-    typedef base::iterator_category iterator_category;
-    typedef base::difference_type difference_type;
-    typedef base::pointer pointer;
-    typedef base::reference reference;
-#endif 
+    typedef std::output_iterator_tag iterator_category;
+    typedef std::ptrdiff_t difference_type;
+    typedef T* pointer;
+    typedef T& reference;
     
     struct proxy
     {

test/is_readable_iterator.cpp

@@ -5,10 +5,10 @@
 #include <deque>
 #include <iterator>
 #include <iostream>
+#include <cstddef> // std::ptrdiff_t
 #include <boost/static_assert.hpp>
 #include <boost/noncopyable.hpp>
 #include <boost/iterator/is_readable_iterator.hpp>
-#include <boost/iterator.hpp>
 
 // Last, for BOOST_NO_LVALUE_RETURN_DETECTION
 #include <boost/iterator/detail/config_def.hpp>
@@ -20,26 +20,35 @@ struct v
 };
 
 
-struct value_iterator : boost::iterator<std::input_iterator_tag,v>
+struct value_iterator
 {
+    typedef std::input_iterator_tag iterator_category;
+    typedef v value_type;
+    typedef std::ptrdiff_t difference_type;
+    typedef v* pointer;
+    typedef v& reference;
+
     v operator*() const;
 };
 
-struct noncopyable_iterator : boost::iterator<std::forward_iterator_tag,boost::noncopyable>
+struct noncopyable_iterator
 {
+    typedef std::forward_iterator_tag iterator_category;
+    typedef boost::noncopyable value_type;
+    typedef std::ptrdiff_t difference_type;
+    typedef boost::noncopyable* pointer;
+    typedef boost::noncopyable& reference;
+	
     boost::noncopyable const& operator*() const;
 };
 
-struct proxy_iterator : boost::iterator<std::output_iterator_tag,v>
+struct proxy_iterator
 {
-#if BOOST_WORKAROUND(__GNUC__, == 2)
-    typedef boost::iterator<std::input_iterator_tag,v> base;
-    typedef base::iterator_category iterator_category;
-    typedef base::value_type value_type;
-    typedef base::difference_type difference_type;
-    typedef base::pointer pointer;
-    typedef base::reference reference;
-#endif 
+    typedef std::output_iterator_tag iterator_category;
+    typedef v value_type;
+    typedef std::ptrdiff_t difference_type;
+    typedef v* pointer;
+    typedef v& reference;
     
     struct proxy
     {
@@ -50,16 +59,13 @@ struct proxy_iterator : boost::iterator<std::output_iterator_tag,v>
     proxy operator*() const;
 };
 
-struct proxy_iterator2 : boost::iterator<std::output_iterator_tag,v>
+struct proxy_iterator2
 {
-#if BOOST_WORKAROUND(__GNUC__, == 2)
-    typedef boost::iterator<std::input_iterator_tag,v> base;
-    typedef base::iterator_category iterator_category;
-    typedef base::value_type value_type;
-    typedef base::difference_type difference_type;
-    typedef base::pointer pointer;
-    typedef base::reference reference;
-#endif 
+    typedef std::output_iterator_tag iterator_category;
+    typedef v value_type;
+    typedef std::ptrdiff_t difference_type;
+    typedef v* pointer;
+    typedef v& reference;
     
     struct proxy
     {

test/range_distance_compat_test.cpp

@@ -0,0 +1,22 @@
+// Copyright (C) 2018 Andrey Semashev
+//
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#include <boost/range/distance.hpp>
+#include <boost/range/iterator_range_core.hpp>
+#include <boost/iterator/distance.hpp>
+
+int main()
+{
+    // Test that boost::distance from Boost.Range works with boost::distance from Boost.Iterator
+    // (https://github.com/boostorg/iterator/commit/b844c8df530c474ec1856870b9b0de5f487b84d4#commitcomment-30603668)
+
+    typedef boost::iterator_range<const char*> range_type;
+    range_type range;
+
+    (void)boost::distance(range);
+
+    return 0;
+}