llvm-project/clang/test/SemaCXX/coroutine-final-suspend-noexcept.cpp

// This file contains references to sections of the Coroutines TS, which can be
// found at http://wg21.link/coroutines.

// RUN: %clang_cc1 -std=c++14 -fcoroutines-ts -verify %s -fcxx-exceptions -fexceptions -Wunused-result

namespace std {
namespace experimental {

template <class Ret, typename... T>
struct coroutine_traits { using promise_type = typename Ret::promise_type; };

template <class Promise = void>
struct coroutine_handle {
  static coroutine_handle from_address(void *); // expected-note 2 {{must be declared with 'noexcept'}}
};
template <>
struct coroutine_handle<void> {
  template <class PromiseType>
  coroutine_handle(coroutine_handle<PromiseType>); // expected-note 2 {{must be declared with 'noexcept'}}
};

struct suspend_never {
  bool await_ready() { return true; }       // expected-note 2 {{must be declared with 'noexcept'}}
  void await_suspend(coroutine_handle<>) {} // expected-note 2 {{must be declared with 'noexcept'}}
  void await_resume() {}                    // expected-note 2 {{must be declared with 'noexcept'}}
  ~suspend_never() noexcept(false);         // expected-note 2 {{must be declared with 'noexcept'}}
};

struct suspend_always {
  bool await_ready() { return false; }
  void await_suspend(coroutine_handle<>) {}
  void await_resume() {}
  suspend_never operator co_await(); // expected-note 2 {{must be declared with 'noexcept'}}
  ~suspend_always() noexcept(false); // expected-note 2 {{must be declared with 'noexcept'}}
};

} // namespace experimental
} // namespace std

using namespace std::experimental;

struct A {
  bool await_ready();
  void await_resume();
  template <typename F>
  void await_suspend(F);
};

struct coro_t {
  struct promise_type {
    coro_t get_return_object();
    suspend_never initial_suspend();
    suspend_always final_suspend(); // expected-note 2 {{must be declared with 'noexcept'}}
    void return_void();
    static void unhandled_exception();
  };
};

coro_t f(int n) { // expected-error {{the expression 'co_await __promise.final_suspend()' is required to be non-throwing}}
  A a{};
  co_await a;
}

template <typename T>
coro_t f_dep(T n) { // expected-error {{the expression 'co_await __promise.final_suspend()' is required to be non-throwing}}
  A a{};
  co_await a;
}

void foo() {
  f_dep<int>(5); // expected-note {{in instantiation of function template specialization 'f_dep<int>' requested here}}
}