[Bug c++/94682] New: coroutines: Promise param preview should get a reference to *this.

[iains at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94682

            Bug ID: 94682
           Summary: coroutines: Promise param preview should get a
                    reference to *this.
           Product: gcc
           Version: 10.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: iains at gcc dot gnu.org
  Target Milestone: ---

Created attachment 48322
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=48322&action=edit
fix being tested.

Reported independently by Michał Dominiak and Lewis Baker.

The static assert fails in the following code, because we should be passing a
reference to *this but we're passing this.

struct promise;

struct future
{
    using promise_type = promise;
};

struct promise
{
    template<typename Class>
    promise(Class &,int) { static_assert(!std::is_pointer<Class>::value, ""); }

    coro::suspend_never initial_suspend() { return {}; }
    coro::suspend_never final_suspend() { return {}; }

    future get_return_object() { return {}; }

    void return_value(int) {}
    void unhandled_exception() {}
};

struct bar
{
future foo(int param)
{
    co_return 0;
}
};