[llvm-branch-commits] [libcxx] [libc++][chrono] Loads leap-seconds.list in tzdb. (PR #82113)

[Louis Dionne via llvm-branch-commits]

================
@@ -0,0 +1,56 @@
+//===----------------------------------------------------------------------===//
+//
+// 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, c++14, c++17
+// UNSUPPORTED: no-filesystem, no-localization, no-tzdb
+
+// XFAIL: libcpp-has-no-incomplete-tzdb
+// XFAIL: availability-tzdb-missing
+
+// <chrono>
+
+// class leap_second
+// {
+//   leap_second& operator=(const leap_second&) = default;
+//
+//   ...
+// };
+
+#include <chrono>
+#include <type_traits>
+#include <cassert>
+
+// Add the include path required by test_chrono_leap_second.h when using libc++.
+// ADDITIONAL_COMPILE_FLAGS(stdlib=libc++): -I %S/../../../../../src/include
+#include "test_chrono_leap_second.h"
+
+constexpr bool test() {
+  std::chrono::leap_second a =
+      test_leap_second_create(std::chrono::sys_seconds{std::chrono::seconds{0}}, std::chrono::seconds{1});
+  std::chrono::leap_second b =
+      test_leap_second_create(std::chrono::sys_seconds{std::chrono::seconds{10}}, std::chrono::seconds{15});
+
+  //  operator== only compares the date member.
+  assert(a.date() != b.date());
+  assert(a.value() != b.value());
+
+  b = a;
----------------
ldionne wrote:

```suggestion
  std::same_as<leap_second&> decltype(auto) result = (b = a);
  assert(&result == &b);
```

Kinda pedantic, but we do it in several places and this ensures that we return the right type, and that we return `*this` from the operator.

https://github.com/llvm/llvm-project/pull/82113