llvm/libcxx/test/std/language.support/support.coroutines/coroutine.trivial.awaitables/suspend_always.pass.cpp

//===----------------------------------------------------------------------===//
//
// 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

#include <coroutine>
#include <type_traits>
#include <cassert>
#include <utility>

#include "test_macros.h"

constexpr bool check_suspend_constexpr() {
  std::suspend_always s{};
  const std::suspend_always scopy(s);
  std::suspend_always smove(std::move(s));
  s = scopy;
  s = std::move(smove);
  return true;
}

template<class T>
constexpr bool test_trivial_awaitable_constexpr(bool expected) {
  T t;
  assert(t.await_ready() == expected);
  t.await_suspend(nullptr);
  t.await_resume();
  return true;
}

int main(int, char**)
{
  std::coroutine_handle<> h{};
  std::suspend_always s{};
  std::suspend_always const& cs = s;
  {
    ASSERT_NOEXCEPT(s.await_ready());
    static_assert(std::is_same<decltype(s.await_ready()), bool>::value, "");
    assert(s.await_ready() == false);
    assert(cs.await_ready() == false);
  }
  {
    ASSERT_NOEXCEPT(s.await_suspend(h));
    static_assert(std::is_same<decltype(s.await_suspend(h)), void>::value, "");
    s.await_suspend(h);
    cs.await_suspend(h);
  }
  {
    ASSERT_NOEXCEPT(s.await_resume());
    static_assert(std::is_same<decltype(s.await_resume()), void>::value, "");
    s.await_resume();
    cs.await_resume();
  }
  {
    static_assert(std::is_nothrow_default_constructible<std::suspend_always>::value, "");
    static_assert(std::is_nothrow_copy_constructible<std::suspend_always>::value, "");
    static_assert(std::is_nothrow_move_constructible<std::suspend_always>::value, "");
    static_assert(std::is_nothrow_copy_assignable<std::suspend_always>::value, "");
    static_assert(std::is_nothrow_move_assignable<std::suspend_always>::value, "");
    static_assert(std::is_trivially_copyable<std::suspend_always>::value, "");
    static_assert(check_suspend_constexpr(), "");
  }
  {
    static_assert(test_trivial_awaitable_constexpr<std::suspend_always>(false));
  }

  return 0;
}