[libcxx-commits] [libcxx] [libc++] Simplify the implementation of std::get for pairs (PR #114984)

[Louis Dionne via libcxx-commits]

================
@@ -0,0 +1,68 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11
+
+// <utility>
+
+// template <class T1, class T2> struct pair
+
+// template<size_t I, class T1, class T2>
+//     typename tuple_element<I, std::pair<T1, T2> >::type&&
+//     get(pair<T1, T2>&&);
+
+#include <cassert>
+#include <utility>
+
+#include "test_macros.h"
+
+TEST_CONSTEXPR_CXX14 bool test() {
+  int i = 1;
+  int j = 2;
+
+  {
+    std::pair<int&, int&&> p(i, std::move(j));
+    assert(&std::get<int&>(p) == &i);
+    assert(&std::get<int&&>(p) == &j);
+
+    assert(&std::get<int&>(std::move(p)) == &i);
+    assert(std::get<int&&>(std::move(p)) == 2);
+
+    const std::pair<int&, int&&> cp(i, std::move(j));
+    assert(&std::get<int&>(cp) == &i);
+    assert(&std::get<int&&>(cp) == &j);
+
+    assert(&std::get<int&>(std::move(cp)) == &i);
+    assert(std::get<int&&>(std::move(cp)) == 2);
+  }
+
+  {
+    std::pair<int&&, int&> p(std::move(i), j);
+    assert(&std::get<int&>(p) == &j);
+    assert(&std::get<int&&>(p) == &i);
+
+    assert(&std::get<int&>(std::move(p)) == &j);
+    assert(std::get<int&&>(std::move(p)) == 1);
+
+    const std::pair<int&&, int&> cp(std::move(i), j);
+    assert(&std::get<int&>(cp) == &j);
+    assert(&std::get<int&&>(cp) == &i);
+
+    assert(&std::get<int&>(std::move(cp)) == &j);
+    assert(std::get<int&&>(std::move(cp)) == 1);
+  }
+
+  return true;
+}
+
+int main() {
+  test();
+#if TEST_STD_VER >= 14
+  static_assert(test(), "");
+#endif
+}
----------------
ldionne wrote:

`return 0;`

https://github.com/llvm/llvm-project/pull/114984