1 // RUN: %clang_cc1 -verify -std=c++20 -fsyntax-only %s
2 
3 #include "Inputs/std-coroutine.h"
4 
5 namespace std::experimental {
6 // expected-note@+1{{declared here}}
7 template <typename T> using coroutine_traits = std::coroutine_traits<T>;
8 using std::coroutine_handle;
9 } // namespace std::experimental
10 
11 struct my_awaitable {
12   bool await_ready() noexcept;
13   void await_suspend(std::experimental::coroutine_handle<> coro) noexcept;
14   void await_resume() noexcept;
15 };
16 
17 struct promise_void {
18   void get_return_object();
19   my_awaitable initial_suspend();
20   my_awaitable final_suspend() noexcept;
21   void return_void();
22   void unhandled_exception();
23 };
24 
25 template <>
26 struct std::coroutine_traits<void> { using promise_type = promise_void; };
27 
test()28 void test() {
29   co_return; // expected-error {{mixed use of std and std::experimental namespaces for coroutine components}}
30   // expected-warning@-1{{support for std::experimental::coroutine_traits will be removed}}
31   // expected-note@Inputs/std-coroutine.h:8 {{'coroutine_traits' declared here}}
32 }
33