On Fri, 14 Apr 2023 at 14:47, Andrey Semashev via Std-Discussion
<std-discussion_at_[hidden]> wrote:

> > > > If it's for RAII, then plain scope_guard should be fine (even if
> > a bit misused; a class type is not a scope). scope_success and
> > scope_failure would not make much sense as data members unless
> > you're writing another success/failure scope guard class (what I
> > meant by composability).
> > >
> > > That I can probably live with.
> >
> > ..except.. I don't think that's wise. I can easily imagine uses where
> > I create an array of scope_fails, a tuple of scope fails, or even
> > a vector of scope_fails. I find it perfectly reasonable to expect such
> > composition to Just Work.
> >
> > Those can trivially be replaced with a single scope_fail referencing an
> > array, tuple or vector of callbacks.
>
> I think the point was that it is unexpected that this wouldn't work
> without this workaround.

Well, it's easy enough to play with that, either using boost or by
just using the TS implementation
that is in libstdc++. The suggestion by Edward sounds semi-plausible..
but the concern remains,
especially for tuple, that the end result is much harder to use than
just a straightforward tuple
of scope_fails.