Add test/variant_visit_cx_2.cpp. Refs #47.

test/Jamfile

@@ -141,4 +141,5 @@ compile variant_uses_double_storage.cpp ;
 run variant_derived_construct2.cpp ;
 
 compile variant_visit_cx.cpp : [ requires cxx14_constexpr ] ;
+compile variant_visit_cx_2.cpp : [ requires cxx14_constexpr ] ;
 compile variant_visit_r_cx.cpp : [ requires cxx14_constexpr ] ;

test/variant_visit_cx_2.cpp

@@ -0,0 +1,53 @@
+// Copyright 2017, 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// http://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/variant2/variant.hpp>
+#include <boost/config/pragma_message.hpp>
+
+#if !( defined(__cpp_constexpr) && __cpp_constexpr >= 201603L )
+
+BOOST_PRAGMA_MESSAGE("Skipping constexpr visit test because __cpp_constexpr < 201603L")
+int main() {}
+
+#elif !defined(BOOST_MP11_HAS_CXX14_CONSTEXPR)
+
+BOOST_PRAGMA_MESSAGE("Skipping constexpr visit test because BOOST_MP11_HAS_CXX14_CONSTEXPR is not defined")
+int main() {}
+
+#else
+
+using namespace boost::variant2;
+
+struct F
+{
+    constexpr int operator()( int x1, int x2 ) const
+    {
+        return x1 + x2;
+    }
+
+    constexpr int operator()( int x1, int x2, int x3 ) const
+    {
+        return x1 + x2 + x3;
+    }
+};
+
+#define STATIC_ASSERT(...) static_assert(__VA_ARGS__, #__VA_ARGS__)
+
+int main()
+{
+    {
+        constexpr variant<char, int> v1( 1 );
+        constexpr variant<char, int> v2( '2' );
+        STATIC_ASSERT( visit( F(), v1, v2 ) == 1 + '2' );
+    }
+
+    {
+        constexpr variant<char, int> v1( 1 );
+        constexpr variant<char, int> v2( 2 );
+        constexpr variant<char, int> v3( '3' );
+        STATIC_ASSERT( visit( F(), v1, v2, v3 ) == 1 + 2 + '3' );
+    }
+}
+
+#endif