diff --git a/include/geom/node_elem.h b/include/geom/node_elem.h
index 974ec8b61c..6810698672 100644
--- a/include/geom/node_elem.h
+++ b/include/geom/node_elem.h
@@ -179,7 +179,8 @@ class NodeElem : public Elem
   /**
    * \returns \p true if the specified (local) node number is a vertex.
    */
-  virtual bool is_vertex(const unsigned int) const override { return true; }
+  virtual bool is_vertex(const unsigned int libmesh_dbg_var(n)) const override
+  { libmesh_assert_not_equal_to (n, invalid_uint); return true; }
 
   /**
    * NodeElem objects don't have faces or sides.
diff --git a/src/geom/cell_hex8.C b/src/geom/cell_hex8.C
index e9a839a438..c82ea9b85c 100644
--- a/src/geom/cell_hex8.C
+++ b/src/geom/cell_hex8.C
@@ -69,8 +69,9 @@ const unsigned int Hex8::edge_nodes_map[Hex8::num_edges][Hex8::nodes_per_edge] =
 // ------------------------------------------------------------
 // Hex8 class member functions
 
-bool Hex8::is_vertex(const unsigned int) const
+bool Hex8::is_vertex(const unsigned int libmesh_dbg_var(n)) const
 {
+  libmesh_assert_not_equal_to (n, invalid_uint);
   return true;
 }
 
diff --git a/src/geom/cell_prism6.C b/src/geom/cell_prism6.C
index c97e607165..27d4589062 100644
--- a/src/geom/cell_prism6.C
+++ b/src/geom/cell_prism6.C
@@ -145,8 +145,9 @@ const unsigned int Prism6::edge_nodes_map[Prism6::num_edges][Prism6::nodes_per_e
 // ------------------------------------------------------------
 // Prism6 class member functions
 
-bool Prism6::is_vertex(const unsigned int) const
+bool Prism6::is_vertex(const unsigned int libmesh_dbg_var(n)) const
 {
+  libmesh_assert_not_equal_to (n, invalid_uint);
   return true;
 }
 
@@ -155,6 +156,7 @@ bool Prism6::is_edge(const unsigned int) const
   return false;
 }
 
+
 bool Prism6::is_face(const unsigned int) const
 {
   return false;
diff --git a/src/geom/cell_pyramid5.C b/src/geom/cell_pyramid5.C
index 0c07c777ab..ce27a58ed7 100644
--- a/src/geom/cell_pyramid5.C
+++ b/src/geom/cell_pyramid5.C
@@ -62,8 +62,9 @@ const unsigned int Pyramid5::edge_nodes_map[Pyramid5::num_edges][Pyramid5::nodes
 // ------------------------------------------------------------
 // Pyramid5 class member functions
 
-bool Pyramid5::is_vertex(const unsigned int) const
+bool Pyramid5::is_vertex(const unsigned int libmesh_dbg_var(n)) const
 {
+  libmesh_assert_not_equal_to (n, invalid_uint);
   return true;
 }
 
diff --git a/src/geom/cell_tet4.C b/src/geom/cell_tet4.C
index 23b29869a4..76538e1d77 100644
--- a/src/geom/cell_tet4.C
+++ b/src/geom/cell_tet4.C
@@ -57,8 +57,9 @@ const unsigned int Tet4::edge_nodes_map[Tet4::num_edges][Tet4::nodes_per_edge] =
 // ------------------------------------------------------------
 // Tet4 class member functions
 
-bool Tet4::is_vertex(const unsigned int) const
+bool Tet4::is_vertex(const unsigned int libmesh_dbg_var(n)) const
 {
+  libmesh_assert_not_equal_to (n, invalid_uint);
   return true;
 }
 
diff --git a/src/geom/edge_edge2.C b/src/geom/edge_edge2.C
index 4600d6bb23..55d70e8522 100644
--- a/src/geom/edge_edge2.C
+++ b/src/geom/edge_edge2.C
@@ -51,8 +51,9 @@ const Real Edge2::_embedding_matrix[Edge2::num_children][Edge2::num_nodes][Edge2
 
 #endif
 
-bool Edge2::is_vertex(const unsigned int) const
+bool Edge2::is_vertex(const unsigned int libmesh_dbg_var(n)) const
 {
+  libmesh_assert_not_equal_to (n, invalid_uint);
   return true;
 }
 
diff --git a/src/geom/face_quad4.C b/src/geom/face_quad4.C
index 9965d8102c..b7a82eb4cd 100644
--- a/src/geom/face_quad4.C
+++ b/src/geom/face_quad4.C
@@ -91,8 +91,9 @@ const Real Quad4::_embedding_matrix[Quad4::num_children][Quad4::num_nodes][Quad4
 // ------------------------------------------------------------
 // Quad4 class member functions
 
-bool Quad4::is_vertex(const unsigned int) const
+bool Quad4::is_vertex(const unsigned int libmesh_dbg_var(n)) const
 {
+  libmesh_assert_not_equal_to (n, invalid_uint);
   return true;
 }
 
diff --git a/src/geom/face_tri3.C b/src/geom/face_tri3.C
index 23ca93b542..5533360d4f 100644
--- a/src/geom/face_tri3.C
+++ b/src/geom/face_tri3.C
@@ -83,8 +83,9 @@ const Real Tri3::_embedding_matrix[Tri3::num_children][Tri3::num_nodes][Tri3::nu
 // ------------------------------------------------------------
 // Tri3 class member functions
 
-bool Tri3::is_vertex(const unsigned int) const
+bool Tri3::is_vertex(const unsigned int libmesh_dbg_var(n)) const
 {
+  libmesh_assert_not_equal_to (n, invalid_uint);
   return true;
 }