diff --git a/include/boost/detail/iterator.hpp b/include/boost/detail/iterator.hpp
index ad75e6a..2498ef4 100644
--- a/include/boost/detail/iterator.hpp
+++ b/include/boost/detail/iterator.hpp
@@ -25,8 +25,8 @@ using std::distance;
 #if defined(__SUNPRO_CC) && (defined(__SGI_STL_PORT) || defined(_STLPORT_VERSION))
 // std::distance from stlport with Oracle compiler 12.4 and 12.5 fails to deduce template parameters
 // when one of the arguments is an array and the other one is a pointer.
-template< typename T, std::size_t N, typename U >
-inline typename std::iterator_traits< T* >::difference_type distance(T (&left)[N], U* right)
+template< typename T, std::size_t N >
+inline typename std::iterator_traits< T* >::difference_type distance(T (&left)[N], T* right)
 {
     return std::distance(static_cast< T* >(left), right);
 }