From d2c5358df89c491c81a9da4d0dc5d316b1715e17 Mon Sep 17 00:00:00 2001
From: Daniel Arndt <arndtd@ornl.gov>
Date: Tue, 20 Jun 2023 17:19:47 -0400
Subject: [PATCH] Use a reference to a const value in one place

---
 include/deal.II/base/index_set.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/deal.II/base/index_set.h b/include/deal.II/base/index_set.h
index c9abbddc7a..7e803b8ec3 100644
--- a/include/deal.II/base/index_set.h
+++ b/include/deal.II/base/index_set.h
@@ -1831,8 +1831,8 @@ IndexSet::n_elements() const
   size_type v = 0;
   if (!ranges.empty())
     {
-      Range &r = ranges.back();
-      v        = r.nth_index_in_set + r.end - r.begin;
+      const Range &r = ranges.back();
+      v              = r.nth_index_in_set + r.end - r.begin;
     }
 
 #ifdef DEBUG
-- 
2.39.5