https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95111
--- Comment #19 from Iain Sandoe <iains at gcc dot gnu.org> ---
(In reply to Ville Voutilainen from comment #17)
> (In reply to Ville Voutilainen from comment #16)
> > (In reply to Iain Sandoe from comment #14)
> > > (In reply to Ville Voutilainen from comment #12)
> > > The idea of bringing the lambda's captures into the coro frame was what I
> > > originally implemented. Richard pointed out that this is wrong when the
> > > lambda is mutable (see
> > > gcc/testsuite/g++.dg/coroutines/torture/lambda-10-mutable.C)
> > >
> > > so if one has
> > >
> > > auto X = [...] () -> some_coro<xxx> {};
> > >
> > > X must exist for the duration of the lambda coro [it was pointed out by
> > > Lewis that really this is only the same as saying that if you have a class
> > > with a member function lambda, the instance of that class has to persist
> > > for
> > > the duration of the coro].
> >
> > Ah. So the work-around for this problem is to copy the capture to a local
> > variable, and co_return that; then the local variable is in the coro-state.
> > Right?
>
> That is, instead of writing
>
> [x] {co_return x;}
>
> write
>
> [x] {auto xx = x; co_return xx;}
hmm I'm not sure this is sufficient; if the initial suspend is suspend-always,
and the closure object goes away before the initial resume, then xx will be
initialised with garbage.
