From 92a3035fb2ffcd9a12f4e945c54165b87400de70 Mon Sep 17 00:00:00 2001
From: Benau <Benau@users.noreply.github.com>
Date: Thu, 8 Dec 2022 16:26:28 +0800
Subject: [PATCH] Fix #4830

---
 src/physics/physics.hpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/physics/physics.hpp b/src/physics/physics.hpp
index d75f1d752..efe2bd5ff 100644
--- a/src/physics/physics.hpp
+++ b/src/physics/physics.hpp
@@ -81,7 +81,7 @@ private:
         /** Tests if two collision pairs involve the same objects. This test
          *  is simplified (i.e. no test if p.b==a and p.a==b) since the
          *  elements are sorted. */
-        bool operator==(const CollisionPair &p)
+        bool operator==(const CollisionPair &p) const
         {
             return (p.m_up[0]==m_up[0] && p.m_up[1]==m_up[1]);
         }   // operator==