[libcxx] LWG2485: get() should be overloaded for const tuple&&. Patch from K-Ballo.

Review: http://reviews.llvm.org/D14839

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@255941 91177308-0d34-0410-b5e6-96231b3b80d8

test/std/containers/sequences/array/array.tuple/get_const_rv.pass.cpp

@@ -0,0 +1,51 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// <array>
+
+// template <size_t I, class T, size_t N> const T&& get(const array<T, N>&& a);
+
+// UNSUPPORTED: c++98, c++03
+
+#include <array>
+#include <memory>
+#include <type_traits>
+#include <utility>
+#include <cassert>
+
+#include "test_macros.h"
+
+// std::array is explicitly allowed to be initialized with A a = { init-list };.
+// Disable the missing braces warning for this reason.
+#include "disable_missing_braces_warning.h"
+
+int main()
+{
+
+    {
+    typedef std::unique_ptr<double> T;
+    typedef std::array<T, 1> C;
+    const C c = {std::unique_ptr<double>(new double(3.5))};
+    static_assert(std::is_same<const T&&, decltype(std::get<0>(std::move(c)))>::value, "");
+    static_assert(noexcept(std::get<0>(std::move(c))), "");
+    const T&& t = std::get<0>(std::move(c));
+    assert(*t == 3.5);
+    }
+
+#if TEST_STD_VER > 11
+    {
+    typedef double T;
+    typedef std::array<T, 3> C;
+    constexpr const C c = {1, 2, 3.5};
+    static_assert(std::get<0>(std::move(c)) == 1, "");
+    static_assert(std::get<1>(std::move(c)) == 2, "");
+    static_assert(std::get<2>(std::move(c)) == 3.5, "");
+    }
+#endif
+}