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Re: [PATCH]: Fix PR c++/88095, class template argument deduction for literal operator templates per P0732 for C++2a
On Tue, Aug 6, 2019 at 11:10 AM Tom Honermann <tom@honermann.net> wrote:
> On 8/5/19 3:05 PM, Jason Merrill wrote:
> > On 8/2/19 9:59 AM, Tom Honermann wrote:
> >> This patch fixes PR c++/88095:
> >> - Bug 88095 - class nontype template parameter UDL string literals
> >> doesn't accepts deduction placeholder
> >> - https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88095.
> >>
> >> It also addresses a latent issue; literal operator templates with
> >> template parameter packs of literal class type were previously
> >> accepted. The patch corrects this and adds a test
> >> (udlit-class-nttp-neg.C).
> >>
> >> In the change to gcc/cp/parser.c, it is not clear to me whether the
> >> 'TREE_CODE (TREE_TYPE (parm)) == TEMPLATE_TYPE_PARM' comparison is
> >> necessary; it might be that 'CLASS_PLACEHOLDER_TEMPLATE' suffices on
> >> its own.
> >
> > template_placeholder_p would be a shorter way to write these, but I
> > think even better would be to just change CLASS_TYPE_P to
> > MAYBE_CLASS_TYPE_P. I'll make that change and commit the patch, since
> > it looks like you don't have commit access yet.
> Thanks, and correct, I don't have commit access yet (and I'm not sure
> that I should! :) )
> >
> >> If accepted, I'd like to request this change be applied to gcc 9 as
> >> it is needed for one of the char8_t remediation approaches documented
> >> in P1423, and may be helpful for existing code bases impacted by the
> >> char8_t changes adopted via P0482 for C++20.
> >> - https://wg21.link/p1423#emulate
> >
> > Seems reasonable. It may be too late to make 9.2 at this point, though.
>
> Is there anything I can/should do to request inclusion?
Appeal to Jakub on the 9.2 freeze thread in the gcc mailing list.
Jason