[Bug c++/100476] coroutines: questionable handling of void get_return_object

[jason at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100476

--- Comment #2 from Jason Merrill <jason at gcc dot gnu.org> ---
(In reply to Iain Sandoe from comment #1)
> I am by no means an expert at reading standardese - and it might be that I'm
> not alone, (library writers might have made the same assumption) but it
> seems to me that:
> 
> http://eel.is/c++draft/dcl.fct.def.coroutine#7
> 
> Doe not make any specification about what get_­return_­object() returns,
> only that it is possible to use it either (a) to initialise the return value
> directly or (b) to construct a return value object from it.

It says that you initialize the return value from get_return_object(), which
sounds like

  return promise.get_return_object();

in a non-coroutine, which is an error if get_return_object returns void.