test/SemaCXX/coroutine-mixed-exp-namespace.cpp

// This file is to test the mixed use of `std::experimental::coroutine*` and `std::coroutine*`
// wouldn't make the compiler to crash and emit the diagnostic message correctly.
// RUN: %clang_cc1 -verify -std=c++20 -fsyntax-only %s

#include "Inputs/std-coroutine-exp-namespace.h"
#include "Inputs/std-coroutine.h" // Second

struct my_awaitable {
  bool await_ready() noexcept;
  void await_suspend(std::experimental::coroutine_handle<> coro) noexcept;
  void await_resume() noexcept;
};

struct promise_void {
  void get_return_object();
  my_awaitable initial_suspend();
  my_awaitable final_suspend() noexcept;
  void return_void();
  void unhandled_exception();
};

template <>
struct std::coroutine_traits<void> { using promise_type = promise_void; };

void test() {
  co_return; // expected-error {{mixed use of std and std::experimental namespaces for coroutine components}}
  // expected-warning@-1{{support for std::experimental::coroutine_traits will be removed}}
  // expected-note@Inputs/std-coroutine-exp-namespace.h:8 {{'coroutine_traits' declared here}}
  // expected-note@Inputs/std-coroutine.h:8 {{'coroutine_traits' declared here}}
}