From 3a2c1bd3d9e1c74bd1184ab674b06cc86441a365 Mon Sep 17 00:00:00 2001
From: Wolfgang Bangerth <bangerth@colostate.edu>
Date: Sun, 26 Dec 2021 10:58:25 -0700
Subject: [PATCH] Add an assertion to GridGenerator::flatten_triangulation().

---
 source/grid/grid_generator.cc | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/source/grid/grid_generator.cc b/source/grid/grid_generator.cc
index b47c8a7a6e..2e2444664e 100644
--- 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);
-- 
2.39.5