https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103953
Bug ID: 103953
Summary: Leak of coroutine return object
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: fchelnokov at gmail dot com
Target Milestone: ---
The following code:
```
#include <coroutine>
#include <iostream>
struct task {
struct promise_type;
using handle_type = std::coroutine_handle<promise_type>;
task(handle_type h) : handle(h) {
std::cout << "task ctor " << this << '\n';
}
task(const task & t) : handle(t.handle) {
std::cout << "task copy ctor " << this << '\n';
}
task(task && t) : handle(std::move(t.handle)) {
std::cout << "task move ctor " << this << '\n';
}
~task() {
std::cout << "task dtor " << this << '\n';
}
struct promise_type {
auto get_return_object() {
return task{handle_type::from_promise(*this)};
}
auto initial_suspend() {
return std::suspend_always {};
}
auto unhandled_exception() {}
auto final_suspend() noexcept {
return std::suspend_always{};
}
void return_void() {}
};
handle_type handle;
void await_resume() {
handle.resume();
}
auto await_suspend(handle_type) {
return handle;
}
auto await_ready() {
return false;
}
};
int main() {
task coroutine_A = []() ->task {
co_return;
}();
task coroutine_B = [&coroutine_A]() ->task {
co_await coroutine_A;
}();
coroutine_B.handle.resume();
}
```
prints
```
task ctor 0x7ffc85d3d598
task ctor 0x7ffc85d3d590
task copy ctor 0x194af30
task dtor 0x7ffc85d3d590
task dtor 0x7ffc85d3d598
```
meaning that one instance of task was not destructed (0x194af30).
Demo: https://gcc.godbolt.org/z/6vnoMGvxo
Related discussion: https://stackoverflow.com/q/70632655/7325599
