1 files changed, 34 insertions, 0 deletions
diff --git a/src/boost/libs/hana/test/pair/empty_storage.cpp b/src/boost/libs/hana/test/pair/empty_storage.cpp
new file mode 100644
index 000000000..000041485
--- /dev/null
+++ b/src/boost/libs/hana/test/pair/empty_storage.cpp
@@ -0,0 +1,34 @@
+// Copyright Louis Dionne 2013-2017
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
+
+#include <boost/hana/pair.hpp>
+
+#include <type_traits>
+namespace hana = boost::hana;
+
+
+struct empty1 { };
+struct empty2 { };
+struct empty3 { };
+struct empty4 { };
+
+// Make sure the storage of a pair is compressed
+static_assert(sizeof(hana::pair<empty1, int>) == sizeof(int), "");
+static_assert(sizeof(hana::pair<int, empty1>) == sizeof(int), "");
+
+// Also make sure that a pair with only empty members is empty too. This is
+// important to ensure, for example, that a tuple of pairs of empty objects
+// will get the EBO.
+static_assert(std::is_empty<hana::pair<empty1, empty2>>{}, "");
+
+// Make sure that a pair of empty pairs is still empty.
+static_assert(std::is_empty<
+  hana::pair<hana::pair<empty1, empty2>, empty3>
+>{}, "");
+
+static_assert(std::is_empty<
+  hana::pair<hana::pair<empty1, empty2>, hana::pair<empty3, empty4>>
+>{}, "");
+
+int main() { }