diff --git a/src/OpenMesh/Core/Mesh/PolyMeshT.cc b/src/OpenMesh/Core/Mesh/PolyMeshT.cc
index 6a957666..c21714ca 100644
--- a/src/OpenMesh/Core/Mesh/PolyMeshT.cc
+++ b/src/OpenMesh/Core/Mesh/PolyMeshT.cc
@@ -93,7 +93,7 @@ typename PolyMeshT<Kernel>::Normal
 PolyMeshT<Kernel>::
 calc_face_normal(FaceHandle _fh) const
 {
-  assert(halfedge_handle(_fh).is_valid());
+  assert(this->halfedge_handle(_fh).is_valid());
   ConstFaceVertexIter fv_it(this->cfv_iter(_fh));
   
   Point p0 = this->point(fv_it);
diff --git a/src/OpenMesh/Core/Mesh/TriMeshT.cc b/src/OpenMesh/Core/Mesh/TriMeshT.cc
index 3bf84417..4b148ce0 100644
--- a/src/OpenMesh/Core/Mesh/TriMeshT.cc
+++ b/src/OpenMesh/Core/Mesh/TriMeshT.cc
@@ -71,7 +71,7 @@ typename TriMeshT<Kernel>::Normal
 TriMeshT<Kernel>::
 calc_face_normal(FaceHandle _fh) const
 {
-  assert(halfedge_handle(_fh).is_valid());
+  assert(this->halfedge_handle(_fh).is_valid());
   ConstFaceVertexIter fv_it(this->cfv_iter(_fh));
 
   const Point& p0(this->point(fv_it));  ++fv_it;