[libcxx-commits] [libcxx] [libc++] Fix triviality of std::pair for trivially copyable types without an assignment operator (PR #95444)

[Louis Dionne via libcxx-commits]

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@@ -0,0 +1,60 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+//
+// This test pins down the ABI of std::pair with respect to being "trivially copyable".
+//
+
+// This test doesn't work when the deprecated ABI to turn off pair triviality is enabled.
+// See libcxx/test/libcxx/utilities/utility/pairs/pairs.pair/abi.non_trivial_copy_move.pass.cpp instead.
+// UNSUPPORTED: libcpp-deprecated-abi-disable-pair-trivial-copy-ctor
+
+#include <type_traits>
+#include <utility>
+
+#include "test_macros.h"
+
+struct trivially_copyable {
+  int arr[4];
+};
+
+struct trivially_copyable_no_assignment {
+  int arr[4];
+  trivially_copyable_no_assignment& operator=(const trivially_copyable_no_assignment&) = delete;
+};
+static_assert(std::is_trivially_copyable<trivially_copyable_no_assignment>::value, "");
+
+struct trivially_copyable_no_construction {
+  int arr[4];
+  trivially_copyable_no_construction()                                                     = default;
+  trivially_copyable_no_construction(const trivially_copyable_no_construction&)            = delete;
+  trivially_copyable_no_construction& operator=(const trivially_copyable_no_construction&) = default;
+};
+static_assert(std::is_trivially_copyable<trivially_copyable_no_construction>::value, "");
+
+static_assert((!std::is_trivially_copyable<std::pair<int&, int> >::value), "");
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ldionne wrote:

I have no idea, removed.

https://github.com/llvm/llvm-project/pull/95444