diff --git a/Stream_lines_2/include/CGAL/Regular_grid_2.h b/Stream_lines_2/include/CGAL/Regular_grid_2.h
index 2ef9c992a01..2e9eb33bc58 100644
--- a/Stream_lines_2/include/CGAL/Regular_grid_2.h
+++ b/Stream_lines_2/include/CGAL/Regular_grid_2.h
@@ -93,7 +93,7 @@ public:
 
 template <class StreamLinesTraits_2>
 inline
-typename Regular_grid_2<StreamLinesTraits_2>::Geom_traits::Iso_rectangle_2
+typename StreamLinesTraits_2::Iso_rectangle_2
 Regular_grid_2<StreamLinesTraits_2>::bbox() const
 {
   return typename Geom_traits::Iso_rectangle_2(0.0, 0.0,
diff --git a/Stream_lines_2/include/CGAL/Triangular_field_2.h b/Stream_lines_2/include/CGAL/Triangular_field_2.h
index 1dd733409c7..df6eb6807f4 100644
--- a/Stream_lines_2/include/CGAL/Triangular_field_2.h
+++ b/Stream_lines_2/include/CGAL/Triangular_field_2.h
@@ -134,7 +134,7 @@ protected:
 
 template <class StreamLinesTraits_2>
 inline
-typename Triangular_field_2<StreamLinesTraits_2>::Geom_traits::Iso_rectangle_2
+typename StreamLinesTraits_2::Iso_rectangle_2
 Triangular_field_2<StreamLinesTraits_2>::bbox() const
 {
   return typename Geom_traits::Iso_rectangle_2(minx, miny, maxx,