diff --git a/include/boost/type_traits/conversion_traits.hpp b/include/boost/type_traits/conversion_traits.hpp
index e95560a..c72bf31 100644
--- a/include/boost/type_traits/conversion_traits.hpp
+++ b/include/boost/type_traits/conversion_traits.hpp
@@ -149,6 +149,8 @@ namespace detail{
    {
       template <class T>
       any_conversion(const T&);
+      template <class T>
+      any_conversion(T&);
    };
    template <class T>
    struct checker