diff --git a/Point_set_processing_3/include/CGAL/mst_orient_normals.h b/Point_set_processing_3/include/CGAL/mst_orient_normals.h
index 72cd4e3b48f..8dd0bd69d92 100644
--- a/Point_set_processing_3/include/CGAL/mst_orient_normals.h
+++ b/Point_set_processing_3/include/CGAL/mst_orient_normals.h
@@ -488,6 +488,7 @@ create_mst_graph(
     CGAL_USE(point_map);
     CGAL_USE(k);
     CGAL_USE(kernel);
+    CGAL_USE(index_map);
 
     // Bring private stuff to scope
     using namespace internal;