From: David Wells <wellsd2@rpi.edu>
Date: Sat, 12 Aug 2017 00:07:52 +0000 (-0400)
Subject: Add a clarifying assertion.
X-Git-Tag: v9.0.0-rc1~974^2~11
X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=647437040967dc6eab881d6d71efa1d8057a2e7e;p=dealii.git

Add a clarifying assertion.
---

diff --git a/source/grid/grid_tools.cc b/source/grid/grid_tools.cc
index 38757cfafd..16c19984e6 100644
--- a/source/grid/grid_tools.cc
+++ b/source/grid/grid_tools.cc
@@ -3602,6 +3602,10 @@ next_cell:
         const typename Triangulation<dim,spacedim>::cell_iterator
         cell = *cell_ptr;
 
+        Assert(!cell->active(),
+               ExcMessage("This function is only valid for a list of cells that "
+                          "have children (i.e., no cell in the list may be active)."));
+
         internal::FixUpDistortedChildCells
         ::fix_up_faces (cell,
                         std::integral_constant<int, dim>(),