diff --git a/Heat_method_3/include/CGAL/Heat_method_3/Surface_mesh_geodesic_distances_3.h b/Heat_method_3/include/CGAL/Heat_method_3/Surface_mesh_geodesic_distances_3.h
index 4777e95dce8..69f024199a1 100644
--- a/Heat_method_3/include/CGAL/Heat_method_3/Surface_mesh_geodesic_distances_3.h
+++ b/Heat_method_3/include/CGAL/Heat_method_3/Surface_mesh_geodesic_distances_3.h
@@ -51,6 +51,14 @@ struct Direct
 struct Intrinsic_Delaunay
 {};
 
+namespace internal {
+  template<typename TriangleMesh>
+  bool has_degenerate_faces(const TriangleMesh& tm);
+
+  template<typename TriangleMesh, typename VertexPointMap>
+  bool has_degenerate_faces(const TriangleMesh& tm, VertexPointMap vpm);
+}
+
 namespace internal {
 template <typename TriangleMesh,
           typename Traits,