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

   1 // This file contains references to sections of the Coroutines TS, which can be
   2 // found at http://wg21.link/coroutines.
   3
   4 // RUN: %clang_cc1 -std=c++20 -verify %s -fcxx-exceptions -fexceptions -Wunused-result
   5
   6 namespace std {
   7
   8 template <class Ret, typename... T>
   9 struct coroutine_traits { using promise_type = typename Ret::promise_type; };
  10
  11 template <class Promise = void>
  12 struct coroutine_handle {
  13   static coroutine_handle from_address(void *);
  14   void *address() const noexcept;
  15 };
  16 template <>
  17 struct coroutine_handle<void> {
  18   template <class PromiseType>
  19   coroutine_handle(coroutine_handle<PromiseType>);
  20   void *address() const noexcept;
  21 };
  22
  23 struct suspend_always {
  24   bool await_ready() { return false; }      // expected-note 2 {{must be declared with 'noexcept'}}
  25   void await_suspend(coroutine_handle<>) {} // expected-note 2 {{must be declared with 'noexcept'}}
  26   void await_resume() {}                    // expected-note 2 {{must be declared with 'noexcept'}}
  27   ~suspend_always() noexcept(false);        // expected-note 2 {{must be declared with 'noexcept'}}
  28 };
  29
  30 } // namespace std
  31
  32 using namespace std;
  33
  34 struct A {
  35   bool await_ready();
  36   void await_resume();
  37   template <typename F>
  38   void await_suspend(F);
  39 };
  40
  41 struct coro_t {
  42   struct promise_type {
  43     coro_t get_return_object();
  44     suspend_always initial_suspend();
  45     suspend_always final_suspend(); // expected-note 2 {{must be declared with 'noexcept'}}
  46     void return_void();
  47     static void unhandled_exception();
  48   };
  49 };
  50
  51 coro_t f(int n) { // expected-error {{the expression 'co_await __promise.final_suspend()' is required to be non-throwing}}
  52   A a{};
  53   co_await a;
  54 }
  55
  56 template <typename T>
  57 coro_t f_dep(T n) { // expected-error {{the expression 'co_await __promise.final_suspend()' is required to be non-throwing}}
  58   A a{};
  59   co_await a;
  60 }
  61
  62 void foo() {
  63   f_dep<int>(5); // expected-note {{in instantiation of function template specialization 'f_dep<int>' requested here}}
  64 }
  65
  66 struct PositiveFinalSuspend {
  67   bool await_ready() noexcept;
  68   coroutine_handle<> await_suspend(coroutine_handle<>) noexcept;
  69   void await_resume() noexcept;
  70 };
  71
  72 struct correct_coro {
  73   struct promise_type {
  74     correct_coro get_return_object();
  75     suspend_always initial_suspend();
  76     PositiveFinalSuspend final_suspend() noexcept;
  77     void return_void();
  78     static void unhandled_exception();
  79   };
  80 };
  81
  82 correct_coro f2(int n) {
  83   co_return;
  84 }
  85
  86 struct NegativeFinalSuspend {
  87   bool await_ready() noexcept;
  88   coroutine_handle<> await_suspend(coroutine_handle<>) noexcept;
  89   void await_resume() noexcept;
  90   ~NegativeFinalSuspend() noexcept(false); // expected-note {{must be declared with 'noexcept'}}
  91 };
  92
  93 struct incorrect_coro {
  94   struct promise_type {
  95     incorrect_coro get_return_object();
  96     suspend_always initial_suspend();
  97     NegativeFinalSuspend final_suspend() noexcept;
  98     void return_void();
  99     static void unhandled_exception();
 100   };
 101 };
 102
 103 incorrect_coro f3(int n) { // expected-error {{the expression 'co_await __promise.final_suspend()' is required to be non-throwing}}
 104   co_return;
 105 }