On Mon, 4 Aug 2025, Jakub Jelinek wrote:
> On Mon, Aug 04, 2025 at 11:33:17AM -0400, Patrick Palka wrote:
> > > @@ -1693,6 +1697,8 @@ export namespace std
> > > {
> > > using std::ranges::advance;
> > > using std::ranges::distance;
> > > + using std::ranges::iter_move;
> > > + using std::ranges::iter_swap;
> >
> > Actually a few lines above we already do:
> >
> > // _Cpo is an implementation detail we can't avoid exposing; if we do the
> > // using in ranges directly, it conflicts with any friend functions of the
> > // same name, which is why the customization points are in an inline
> > // namespace in the first place.
> > namespace ranges::inline _Cpo
> > {
> > using _Cpo::iter_move;
> > using _Cpo::iter_swap;
> > }
> >
> > So I think we don't want to export iter_move and iter_swap directly...
> > Sorry
> > for not catching this sooner :/
>
> Oops, missed that (but already committed).
> Note, I haven't seen errors when compiling the module but perhaps the
> conflicts are diagnosed when using those after import std;?
IIRC Jason ran into these errors when experiminting with using the std
module for the entire libstdc++ testsuite? I don't think we have any
direct tests for it ATM.
>
> Anyway, will test following to undo that.
>
> For later, I think it would be useful to commit an improved version of
> the plugin and say compile it during make check, maintain some whitelist
> and diagnose new symbols that appear; plus if not already done try to
> compile during make check the std.cc etc. modules in all the supported
> language modes. So that when people add new features get notified if
> they haven't updated std.cc.in. And this std::ranges::iter_{move,swap}
> case could there be as an exception next to entities removed in C++17/20.
That'd be nice! It's too easy to forget to update std.cc.in
Basically every non-uglified symbol should be exprorted.
>
> BTW, there are some entities removed in C++23 which are not exported:
> using std::declare_no_pointers;
> using std::declare_reachable;
> using std::get_pointer_safety;
> using std::get_unexpected;
> using std::pointer_safety;
> using std::set_unexpected;
> using std::undeclare_no_pointers;
> using std::undeclare_reachable;
> using std::unexpected_handler;
> Wonder if they should be exported in C++20 only or kept unexported.
The unexpected stuff seem to be removed in C++17? The GC stuff we never
really implemented so there's probably no point in exporting them.
>
> 2025-08-04 Jakub Jelinek <[email protected]>
>
> PR libstdc++/121373
> * src/c++23/std.cc.in (std::ranges::iter_move, std::ranges::iter_swap):
> Remove exports.
LGTM FWIW
>
> --- libstdc++-v3/std.cc.in.jj 2025-08-04 17:12:52.133783084 +0200
> +++ libstdc++-v3/std.cc.in 2025-08-04 17:45:00.651437214 +0200
> @@ -1697,8 +1697,6 @@ export namespace std
> {
> using std::ranges::advance;
> using std::ranges::distance;
> - using std::ranges::iter_move;
> - using std::ranges::iter_swap;
> using std::ranges::next;
> using std::ranges::prev;
> }
>
>
> Jakub
>
>
