avoid SFINAE problem in iterator_range constructor

include/boost/range/iterator_range_core.hpp

@@ -442,8 +442,8 @@ public:
             > base_type;
 
             template<class Source>
-            struct is_compatible_range
-                : is_convertible<
+            struct is_compatible_range_
+              : is_convertible<
                     BOOST_DEDUCED_TYPENAME mpl::eval_if<
                         has_range_iterator<Source>,
                         range_iterator<Source>,
@@ -454,6 +454,20 @@ public:
             {
             };
 
+            template<class Source>
+            struct is_compatible_range
+                : mpl::and_<
+                    mpl::not_<
+                        is_convertible<
+                            Source,
+                            BOOST_DEDUCED_TYPENAME base_type::iterator
+                        >
+                    >,
+                    is_compatible_range_<Source>
+                >
+            {
+            };
+
         protected:
             typedef iterator_range_detail::iterator_range_impl<IteratorT> impl;