Add an assertion to GridGenerator::flatten_triangulation().

diff --git a/source/grid/grid_generator.cc b/source/grid/grid_generator.cc
index b47c8a7a6ec886348b919d364a7008fe8f76bb1c..2e2444664ed111fcc8bc03d12897ce907a4cb19f 100644 (file)
--- a/source/grid/grid_generator.cc
+++ b/source/grid/grid_generator.cc
@@ -7500,6 +7500,9 @@ namespace GridGenerator
            ExcMessage(
              "This function cannot be used on "
              "parallel::distributed::Triangulation objects as inputs."));
+    Assert(in_tria.has_hanging_nodes() == false,
+           ExcMessage("This function does not work for meshes that have "
+                      "hanging nodes."));
 
 
     const unsigned int spacedim = std::min(spacedim1, spacedim2);