From 125fdbdf4dd174388cf9467e58de7a7c151bad77 Mon Sep 17 00:00:00 2001
From: Wolfgang Bangerth <bangerth@colostate.edu>
Date: Fri, 5 Feb 2021 09:31:11 -0700
Subject: [PATCH] Avoid using a function in a context in which it makes no
 sense.

---
 source/grid/tria.cc | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/source/grid/tria.cc b/source/grid/tria.cc
index b209875d17..42c6d73a6a 100644
--- a/source/grid/tria.cc
+++ b/source/grid/tria.cc
@@ -13528,8 +13528,11 @@ template <int dim, int spacedim>
 bool
 Triangulation<dim, spacedim>::all_reference_cells_are_hyper_cube() const
 {
-  return (this->reference_cells.size() == 0) ||
-         (this->reference_cells.size() == 1 &&
+  Assert(this->reference_cells.size() > 0,
+         ExcMessage("You can't ask about the kinds of reference "
+                    "cells used by this triangulation if the "
+                    "triangulation doesn't yet have any cells in it."));
+  return (this->reference_cells.size() == 1 &&
           this->reference_cells[0] == ReferenceCell::get_hypercube<dim>());
 }
 
-- 
2.39.5