diff --git a/Nef_S2/include/CGAL/Nef_S2/SM_constrained_triang_traits.h b/Nef_S2/include/CGAL/Nef_S2/SM_constrained_triang_traits.h
index 0a736a26960..2af686090c7 100644
--- a/Nef_S2/include/CGAL/Nef_S2/SM_constrained_triang_traits.h
+++ b/Nef_S2/include/CGAL/Nef_S2/SM_constrained_triang_traits.h
@@ -60,6 +60,15 @@ public:
   typedef Decorator_                                 OUTPUT;
   typedef Kernel_                                    GEOMETRY;
 
+  using Base::is_isolated;
+  using Base::first_out_edge;
+  using Base::last_out_edge;
+  using Base::new_svertex;
+  using Base::assoc_info;
+  using Base::incident_mark;
+  using Base::cyclic_adj_succ;
+  using Base::cyclic_adj_pred;
+  using Base::delete_vertex;
 
   class lt_edges_in_sweepline : public Decorator_
   {  const Point& p;
diff --git a/Nef_S2/include/CGAL/Nef_S2/SM_point_locator.h b/Nef_S2/include/CGAL/Nef_S2/SM_point_locator.h
index d8f86f3e1b6..34cd77fad99 100644
--- a/Nef_S2/include/CGAL/Nef_S2/SM_point_locator.h
+++ b/Nef_S2/include/CGAL/Nef_S2/SM_point_locator.h
@@ -180,7 +180,7 @@ public:
   enum SOLUTION { is_vertex_, is_edge_, is_loop_ };
   // enumeration for internal use
 
-  Object_handle locate(const Sphere_point& p, bool skipVEL = false)
+  Object_handle locate(const Sphere_point& p, bool skipVEL = false) const
   /*{\Mop returns a generic handle |h| to an object (vertex, halfedge,
   face) of the underlying plane map |P| which contains the point |p =
   s.source()| in its relative interior. |s.target()| must be a point
@@ -335,7 +335,7 @@ public:
     Sphere_circle c(d.circle());
     Sphere_segment s;
     bool s_init(false);
-    Object_handle h = locate(p);
+    Object_handle h = this->locate(p);
     SVertex_handle v; 
     SHalfedge_handle e; 
     SHalfloop_handle l; 
diff --git a/Nef_S2/include/CGAL/Nef_S2/SM_triangulator.h b/Nef_S2/include/CGAL/Nef_S2/SM_triangulator.h
index 63c9819410e..88e5af2dd24 100644
--- a/Nef_S2/include/CGAL/Nef_S2/SM_triangulator.h
+++ b/Nef_S2/include/CGAL/Nef_S2/SM_triangulator.h
@@ -174,6 +174,23 @@ public:
   typedef std::pair<Sphere_segment,Sphere_segment> Seg_pair;
   typedef CGAL::Unique_hash_map<Seg_iterator,Object_handle> Seg_map;
 
+  using Base::info;
+  using Base::set_first_out_edge;
+  using Base::first_out_edge;
+  using Base::last_out_edge;
+  using Base::is_isolated;
+  using Base::has_outdeg_two;
+  using Base::flip_diagonal;
+  using Base::out_edges;
+  using Base::set_source;
+  using Base::set_face;
+  using Base::link_as_prev_next_pair;
+  using Base::delete_vertex_only;
+  using Base::delete_edge_pair_only;
+  using Base::is_sm_boundary_object;
+  using Base::store_sm_boundary_object;
+  using Base::undo_sm_boundary_object;
+
   // vertex_info stores the origin of vertices
   struct vertex_info {
     Object_handle         o_;