zircon/system/ulib/stdcompat/test/utility_test.cc

// Copyright 2021 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include <lib/stdcompat/utility.h>

#include <gtest/gtest.h>

namespace {

TEST(InplaceTagTest, InplaceTagsSwitchToStdProvidedOnStd17) {
  static_assert(std::is_trivially_default_constructible<cpp17::in_place_t>::value);
  static_assert(std::is_trivially_default_constructible<cpp17::in_place_index_t<0>>::value);
  static_assert(std::is_trivially_default_constructible<cpp17::in_place_type_t<void>>::value);

#if __cplusplus >= 201411L && !defined(LIB_STDCOMPAT_USE_POLYFILLS)
  static_assert(std::is_same<cpp17::in_place_t, std::in_place_t>::value);
  static_assert(std::is_same<cpp17::in_place_type_t<void>, std::in_place_type_t<void>>::value);
  static_assert(std::is_same<cpp17::in_place_index_t<0>, std::in_place_index_t<0>>::value);

  static_assert(std::addressof(cpp17::in_place) == std::addressof(std::in_place));
  static_assert(std::addressof(cpp17::in_place_type<void>) ==
                std::addressof(std::in_place_type<void>));
  static_assert(std::addressof(cpp17::in_place_index<0>) == std::addressof(std::in_place_index<0>));
#else  // Force template instantiation.

  // Sanity checks that the instantiations are actually different for the polyfills.
  static_assert(std::addressof(cpp17::in_place) != nullptr);
  static_assert(static_cast<const void*>(std::addressof(cpp17::in_place_type<void>)) !=
                static_cast<const void*>(std::addressof(std::in_place_type<int>)));
  static_assert(static_cast<const void*>(std::addressof(cpp17::in_place_index<0>)) !=
                static_cast<const void*>(std::addressof(std::in_place_index<1>)));
#endif
}

}  // namespace