[PATCH] libstdc++: Work around C++20 tuple<tuple<any>> constraint recursion [PR116440]

[Ville Voutilainen]

On Thu, 13 Mar 2025 at 23:57, Jonathan Wakely <jwakely@redhat.com> wrote:
> > Do we also want to constraint the tuple(const _Elements&...)
> > constructor with requires sizeof...(_Elements) >= 1, which is present
> > on the C++17 version?
>
> Oh we don't need that constraint, because we have an explicit
> specialization for tuple<>.

Are.. ..you sure? What about CTAD? That will look into the primary
template only, and will perform its madness based on that
and nothing else.