1 files changed, 75 insertions, 0 deletions
diff --git a/src/boost/libs/hana/test/tuple/pair_interop.cpp b/src/boost/libs/hana/test/tuple/pair_interop.cpp
new file mode 100644
index 000000000..1e079f437
--- /dev/null
+++ b/src/boost/libs/hana/test/tuple/pair_interop.cpp
@@ -0,0 +1,75 @@
+// Copyright Louis Dionne 2013-2016
+// 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/at.hpp>
+#include <boost/hana/first.hpp>
+#include <boost/hana/pair.hpp>
+#include <boost/hana/second.hpp>
+#include <boost/hana/tuple.hpp>
+namespace hana = boost::hana;
+
+
+// This test makes sure that tuples containing pairs behave properly. It is
+// useful to test this specific case because tuple and pair (may) share a lot
+// of implementation details (for EBO), and that can easily lead to subtle bugs.
+// For example, if both pair and tuple inherit from similar base classes for
+// EBO, accessing a tuple of pairs or a pair of tuples (which requires some
+// base class casting magic) can lead to ambiguous overloads.
+
+int main() {
+    struct empty1 { };
+    struct empty2 { };
+
+    {
+        hana::tuple<hana::pair<empty1, empty2>> t{};
+        hana::first(hana::at_c<0>(t));
+        hana::second(hana::at_c<0>(t));
+    }
+    {
+        hana::tuple<hana::pair<int, empty2>> t{};
+        hana::first(hana::at_c<0>(t));
+        hana::second(hana::at_c<0>(t));
+    }
+    {
+        hana::tuple<hana::pair<int, int>> t{};
+        hana::first(hana::at_c<0>(t));
+        hana::second(hana::at_c<0>(t));
+    }
+    {
+        hana::tuple<hana::pair<empty1, int>> t{};
+        hana::first(hana::at_c<0>(t));
+        hana::second(hana::at_c<0>(t));
+    }
+
+    {
+        hana::pair<hana::tuple<>, hana::tuple<>> p{};
+        hana::first(p);
+        hana::second(p);
+    }
+    {
+        hana::pair<hana::tuple<int>, hana::tuple<int>> p{};
+        hana::first(p);
+        hana::second(p);
+    }
+    {
+        hana::pair<hana::tuple<>, hana::tuple<int>> p{};
+        hana::first(p);
+        hana::second(p);
+    }
+    {
+        hana::pair<hana::tuple<empty1>, hana::tuple<empty2>> p{};
+        hana::first(p);
+        hana::second(p);
+    }
+    {
+        hana::pair<hana::tuple<empty1, empty2>, hana::tuple<empty2>> p{};
+        hana::first(p);
+        hana::second(p);
+    }
+    {
+        hana::pair<hana::tuple<empty1, empty2>, hana::tuple<empty1, empty2>> p{};
+        hana::first(p);
+        hana::second(p);
+    }
+}