[Bug libstdc++/97561] New: coroutine_handle doesn't have inheritance

[stinkingmadgod at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97561

            Bug ID: 97561
           Summary: coroutine_handle doesn't have inheritance
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: stinkingmadgod at gmail dot com
  Target Milestone: ---

std::coroutine_handle<promise_type> doesn't inherit from
std::coroutine_handle<void>.

[coroutine.handle.general]
template<class Promise>
struct coroutine_handle : coroutine_handle<>

#include<coroutine>
struct task {
    struct promise_type {
        task get_return_object() { return {}; }
        std::suspend_never initial_suspend() { return {}; }
        std::suspend_never final_suspend() { return {}; }
        void return_void() {}
        void unhandled_exception() {}
    };
};

int main()
{
    std::coroutine_handle<task::promise_type> c;
    std::coroutine_handle<>& c2 = c;  // fails
}