clang/test/SemaCXX/coroutine-alloc-2.cpp

   1 // Tests that we wouldn't generate an allocation call in promise_type with (std::size_t, std::nothrow_t) in case we find promsie_type::get_return_object_on_allocation_failure;
   2 // RUN: %clang_cc1 %s -std=c++20 %s -fsyntax-only -verify
   3
   4 namespace std {
   5 template <typename... T>
   6 struct coroutine_traits;
   7
   8 template <class Promise = void>
   9 struct coroutine_handle {
  10   coroutine_handle() = default;
  11   static coroutine_handle from_address(void *) noexcept { return {}; }
  12 };
  13
  14 template <>
  15 struct coroutine_handle<void> {
  16   static coroutine_handle from_address(void *) { return {}; }
  17   coroutine_handle() = default;
  18   template <class PromiseType>
  19   coroutine_handle(coroutine_handle<PromiseType>) noexcept {}
  20 };
  21
  22 struct suspend_always {
  23   bool await_ready() noexcept { return false; }
  24   void await_suspend(std::coroutine_handle<>) noexcept {}
  25   void await_resume() noexcept {}
  26 };
  27
  28 struct nothrow_t {};
  29 constexpr nothrow_t nothrow = {};
  30
  31 } // end namespace std
  32
  33 using SizeT = decltype(sizeof(int));
  34
  35 struct promise_on_alloc_failure_tag {};
  36
  37 template <>
  38 struct std::coroutine_traits<int, promise_on_alloc_failure_tag> {
  39   struct promise_type {
  40     int get_return_object() { return 0; }
  41     std::suspend_always initial_suspend() { return {}; }
  42     std::suspend_always final_suspend() noexcept { return {}; }
  43     void return_void() {}
  44     void unhandled_exception() {}
  45     static int get_return_object_on_allocation_failure() { return -1; }
  46     void *operator new(SizeT, std::nothrow_t) noexcept;
  47   };
  48 };
  49
  50 extern "C" int f(promise_on_alloc_failure_tag) { // expected-error 1+{{is not usable with the function signature of 'f'}}
  51     co_return;
  52 }