Add an assertion.

diff --git a/source/dofs/dof_handler_policy.cc b/source/dofs/dof_handler_policy.cc
index 508f0c188dad34c89a555b980bde0a81777693bc..d772c57e954158fdc90533df0fa16fd447598bf9 100644 (file)
--- a/source/dofs/dof_handler_policy.cc
+++ b/source/dofs/dof_handler_policy.cc
@@ -3730,6 +3730,14 @@ namespace internal
                                                    triangulation->coarse_cell_to_p4est_tree_permutation,
                                                    triangulation->p4est_tree_to_coarse_cell_permutation);
 
+          // at this point, we must have taken care of the data transfer
+          // on all cells we had previously marked. verify this
+#ifdef DEBUG
+          for (auto cell : dof_handler->active_cell_iterators())
+            Assert (cell->user_flag_set() == false,
+                    ExcInternalError());
+#endif
+
           triangulation->load_user_flags(user_flags);
         }