Re: [PATCH gcc/* 1/2] gcc: copy expected and optional out of rust/utils

On Tue, Aug 18, 2026 at 11:35:21AM +0200, Arsen Arsenović wrote:
> Jason Merrill <[email protected]> writes:
> 
> > On 7/5/26 5:15 PM, Arsen Arsenović wrote:
> >> In my attempts to remove these duplicates from the Rust frontend, I
> >> broke it horribly.  So, I'm leaving them in the Rust frontend.  Help
> >> wanted!
> >> gcc/ChangeLog:
> >> 	* util/expected.h: New file.  Copied out of rust/util.
> >
> > Creating gcc/util seems novel, usually utility headers go directly in gcc/ or
> > in include/.
> 
> Yes, that's the structure the Rust FE was using, and I though it'd be
> nice to curtail expanding gcc/ a bit (it's already at 1095 entries), so
> I kept it.
> 
> But, I can move it elsewhere if so desired.
> 
> What may be an issue with include/ is that (at the moment, anyway) the
> headers are using gcc_assert.

Please put it into gcc/ directly then.
I really dislike other subdirs with extremely few files, it is significant
inbalance having directories for almost nothing vs. the 1000+ files
directory, e.g. the gcc/topics/ directory containing a single header, or
gcc/custom-sarif-properties/ which has 6 files in it or
gcc/sym-exec/ with 7 files in it.  All those would be better in gcc/
directly, custom-sarif-properties with some file prefixes, sym-exec as is.

And yes, I'd think we should based it on libstdc++ implemenntation rather
than some third party (sure, some tweaks will be needed, we need to work with
any C++14 implementation, so stop relying on stuff from <bits/c++config>).

Also, I'd say we should use <expected>/<optional> directly when being
compiled with C++23 resp. C++17, only use the extra headers as fallback
for older C++ compilation, so that when we eventually bump minimum C++
version to C++17 (or much later to C++23), we can remove those headers.

	Jakub