diff --git a/Arrangement_on_surface_2/include/CGAL/Arr_segment_traits_2.h b/Arrangement_on_surface_2/include/CGAL/Arr_segment_traits_2.h
index 8e48f735158..44f65d9b056 100644
--- a/Arrangement_on_surface_2/include/CGAL/Arr_segment_traits_2.h
+++ b/Arrangement_on_surface_2/include/CGAL/Arr_segment_traits_2.h
@@ -1482,7 +1482,7 @@ Arr_segment_2<Kernel>::Arr_segment_2(const Line_2& line,
 
 //! \brief casts to a segment.
 template <typename Kernel>
-Arr_segment_2<Kernel>::operator Segment_2() const
+Arr_segment_2<Kernel>::operator typename Kernel::Segment_2() const
 {
   Kernel kernel;
   auto seg_ctr = kernel.construct_segment_2_object();