From 39d60cd91d74c0d05eb26650672f28e9d2c9f474 Mon Sep 17 00:00:00 2001
From: Christian Mazakas <christian.mazakas@gmail.com>
Date: Wed, 9 Feb 2022 11:06:10 -0800
Subject: [PATCH] Update test metafunction to use `boost::declval` instead of
 using null pointers

---
 test/helpers/metafunctions.hpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/test/helpers/metafunctions.hpp b/test/helpers/metafunctions.hpp
index f5f13851..137aeca1 100644
--- a/test/helpers/metafunctions.hpp
+++ b/test/helpers/metafunctions.hpp
@@ -8,6 +8,7 @@
 
 #include <boost/config.hpp>
 #include <boost/type_traits/is_same.hpp>
+#include <boost/type_traits/declval.hpp>
 
 namespace test {
   template <class Container>
@@ -23,7 +24,9 @@ namespace test {
     BOOST_STATIC_CONSTANT(bool,
       value = sizeof(long) ==
               sizeof(flip(
-                ((Container*)0)->insert(*(typename Container::value_type*)0))));
+                (boost::declval<Container*>())
+                  ->insert(
+                    boost::declval<typename Container::value_type const&>()))));
   };
 }