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From: "lemourin at gmail dot com" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c++/99576] New: [coroutines] desctructor of a temporary called too early within co_await expression Date: Sat, 13 Mar 2021 13:54:16 +0000 [thread overview] Message-ID: <bug-99576-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99576 Bug ID: 99576 Summary: [coroutines] desctructor of a temporary called too early within co_await expression Product: gcc Version: 10.2.1 Status: UNCONFIRMED Keywords: wrong-code Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: lemourin at gmail dot com Target Milestone: --- ``` #if __has_include(<coroutine>) #include <coroutine> namespace stdx { using std::coroutine_handle; using std::noop_coroutine; using std::suspend_always; using std::suspend_never; } // namespace stdx #elif __has_include(<experimental/coroutine>) #include <experimental/coroutine> namespace stdx { using std::experimental::coroutine_handle; using std::experimental::noop_coroutine; using std::experimental::suspend_always; using std::experimental::suspend_never; } // namespace stdx #else #error "coroutines unsupported" #endif #include <exception> #include <iostream> #include <utility> class Task { public: struct promise_type { struct final_awaitable { bool await_ready() noexcept { return false; } auto await_suspend(stdx::coroutine_handle<promise_type> coro) noexcept { return coro.promise().continuation; } void await_resume() noexcept {} }; Task get_return_object() { return Task(stdx::coroutine_handle<promise_type>::from_promise(*this)); } stdx::suspend_always initial_suspend() { return {}; } final_awaitable final_suspend() noexcept { return {}; } void unhandled_exception() { std::terminate(); } void return_void() {} stdx::coroutine_handle<void> continuation = stdx::noop_coroutine(); }; Task(const Task&) = delete; Task(Task&& other) noexcept : handle_(std::exchange(other.handle_, nullptr)) {} Task& operator=(const Task&) = delete; Task& operator=(Task&& other) noexcept { handle_ = std::exchange(other.handle_, nullptr); return *this; } ~Task() { if (handle_) { handle_.destroy(); } } bool await_ready() const { return false; } auto await_suspend(stdx::coroutine_handle<void> continuation) { handle_.promise().continuation = continuation; return handle_; } void await_resume() {} private: explicit Task(stdx::coroutine_handle<promise_type> handle) : handle_(handle) {} stdx::coroutine_handle<promise_type> handle_; }; struct RunTask { struct promise_type { RunTask get_return_object() { return {}; } stdx::suspend_never initial_suspend() { return {}; } stdx::suspend_never final_suspend() noexcept { return {}; } void return_void() {} void unhandled_exception() { std::terminate(); } }; }; struct Foo { Foo() { std::cerr << "Foo()\n"; } ~Foo() { std::cerr << "~Foo()\n"; } }; Task DoAsync() { std::cerr << "START TASK\n"; co_return co_await [foo = Foo{}]() -> Task { std::cerr << "IN LAMBDA\n"; co_return; }(); } RunTask Main() { co_await DoAsync(); } int main() { Main(); } ``` gcc outputs: ` START TASK Foo() ~Foo() IN LAMBDA ` while clang and msvc output: ` START TASK Foo() IN LAMBDA ~Foo() ` Is this code undefined behavior? Or is clang and msvc wrong?
next reply other threads:[~2021-03-13 13:54 UTC|newest] Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-03-13 13:54 lemourin at gmail dot com [this message] 2021-05-14 16:21 ` [Bug c++/99576] [coroutines] destructor " nilsgladitz at gmail dot com 2021-05-15 12:31 ` nilsgladitz at gmail dot com 2021-06-10 14:14 ` davidledger at live dot com.au 2021-06-23 8:54 ` victor.burckel at gmail dot com 2021-10-01 19:57 ` iains at gcc dot gnu.org 2022-11-25 11:50 ` adrian.perl at web dot de 2022-11-25 15:13 ` iains at gcc dot gnu.org 2022-11-26 16:28 ` adrian.perl at web dot de 2022-11-26 16:40 ` iains at gcc dot gnu.org 2022-11-27 14:24 ` adrian.perl at web dot de 2022-11-27 15:42 ` iains at gcc dot gnu.org 2022-11-27 16:08 ` adrian.perl at web dot de 2022-11-28 19:13 ` adrian.perl at web dot de 2022-11-30 11:47 ` iains at gcc dot gnu.org 2022-11-30 23:38 ` iains at gcc dot gnu.org 2022-12-02 20:54 ` iains at gcc dot gnu.org 2022-12-04 10:41 ` cvs-commit at gcc dot gnu.org 2023-07-07 9:32 ` rguenth at gcc dot gnu.org
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