diff --git a/example/cpp11/asymmetric/Jamfile.v2 b/example/cpp11/asymmetric/Jamfile.v2
index 2900897..335f780 100644
--- a/example/cpp11/asymmetric/Jamfile.v2
+++ b/example/cpp11/asymmetric/Jamfile.v2
@@ -41,6 +41,10 @@ exe layout
     : layout.cpp
     ;
 
+exe iterator_range
+    : iterator_range.cpp
+    ;
+
 #exe await_emu
 #    : await_emu.cpp
 #    ;
diff --git a/example/cpp11/asymmetric/iterator_range.cpp b/example/cpp11/asymmetric/iterator_range.cpp
new file mode 100644
index 0000000..32e56d7
--- /dev/null
+++ b/example/cpp11/asymmetric/iterator_range.cpp
@@ -0,0 +1,30 @@
+
+//          Copyright Oliver Kowalke 2009.
+// 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 <cstdlib>
+#include <iostream>
+
+#include <boost/coroutine/all.hpp>
+
+#include <boost/range/adaptor/filtered.hpp>
+#include <boost/range/iterator_range.hpp>
+#include <iostream>
+
+int main()
+{
+    using namespace boost;
+    coroutines::coroutine<int>::pull_type c([](coroutines::coroutine<int>::push_type& yield) {
+        for (int i = 0; i < 5; ++i) {
+            yield(i);
+        }
+    });
+    auto crange = make_iterator_range(begin(c), end(c));
+    for (auto n : crange
+            | adaptors::filtered([](int n){return n % 2 == 0;})) // the filtered adaptor needs const operator==.
+        {
+        std::cout << n << std::endl;
+    }
+}
diff --git a/include/boost/coroutine/asymmetric_coroutine.hpp b/include/boost/coroutine/asymmetric_coroutine.hpp
index 1168f98..9b3370a 100644
--- a/include/boost/coroutine/asymmetric_coroutine.hpp
+++ b/include/boost/coroutine/asymmetric_coroutine.hpp
@@ -190,10 +190,10 @@ public:
             return * this;
         }
 
-        bool operator==( iterator const& other)
+        bool operator==( iterator const& other) const
         { return other.c_ == c_; }
 
-        bool operator!=( iterator const& other)
+        bool operator!=( iterator const& other) const
         { return other.c_ != c_; }
 
         iterator & operator*()
@@ -353,10 +353,10 @@ public:
             return * this;
         }
 
-        bool operator==( iterator const& other)
+        bool operator==( iterator const& other) const
         { return other.c_ == c_; }
 
-        bool operator!=( iterator const& other)
+        bool operator!=( iterator const& other) const
         { return other.c_ != c_; }
 
         iterator & operator*()
@@ -845,10 +845,10 @@ public:
             return * this;
         }
 
-        bool operator==( iterator const& other)
+        bool operator==( iterator const& other) const
         { return other.c_ == c_ && other.val_ == val_; }
 
-        bool operator!=( iterator const& other)
+        bool operator!=( iterator const& other) const
         { return other.c_ != c_ || other.val_ != val_; }
 
         iterator & operator++()
@@ -1227,10 +1227,10 @@ public:
             return * this;
         }
 
-        bool operator==( iterator const& other)
+        bool operator==( iterator const& other) const
         { return other.c_ == c_ && other.val_ == val_; }
 
-        bool operator!=( iterator const& other)
+        bool operator!=( iterator const& other) const
         { return other.c_ != c_ || other.val_ != val_; }
 
         iterator & operator++()