Ping.
On Wed, Apr 22, 2026 at 01:36:52PM -0400, Marek Polacek wrote:
> On Tue, Apr 21, 2026 at 05:20:02PM -0400, Jason Merrill wrote:
> > On 4/21/26 4:21 PM, Marek Polacek wrote:
> > > Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
> > >
> > > -- >8 --
> > > wrapup_namespace_globals gives errors for code like
> > >
> > > extern inline int i;
> > > int &r = i; // odr-used inline variable is not defined
> > >
> > > but because we mark consteval-only vars DECL_EXTERNAL, we also wrongly
> > > emit the error for:
> > >
> > > inline constexpr info value{};
> > > static_assert(value == info{});
> > >
> > > where value clearly is defined. ISTM that we should check
> > > !consteval_only_p
> > > before giving this error because the test where this could trigger:
> > >
> > > extern constexpr inline info x;
> > >
> > > is already ill-formed ("declaration of 'constexpr' variable 'x' is not
> > > a definition").
> > >
> > > PR c++/124770
> > >
> > > gcc/cp/ChangeLog:
> > >
> > > * decl.cc (wrapup_namespace_globals): Don't give the odr-used
> > > inline variable error for consteval-only variables.
> > >
> > > gcc/testsuite/ChangeLog:
> > >
> > > * g++.dg/reflect/init18.C: New test.
> > > ---
> > > gcc/cp/decl.cc | 6 +++++-
> > > gcc/testsuite/g++.dg/reflect/init18.C | 14 ++++++++++++++
> > > 2 files changed, 19 insertions(+), 1 deletion(-)
> > > create mode 100644 gcc/testsuite/g++.dg/reflect/init18.C
> > >
> > > diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc
> > > index 679a8007ca6..7837e322d17 100644
> > > --- a/gcc/cp/decl.cc
> > > +++ b/gcc/cp/decl.cc
> > > @@ -1024,7 +1024,11 @@ wrapup_namespace_globals ()
> > > if (VAR_P (decl)
> > > && DECL_EXTERNAL (decl)
> > > && DECL_INLINE_VAR_P (decl)
> > > - && DECL_ODR_USED (decl))
> > > + && DECL_ODR_USED (decl)
> > > + /* We mark consteval-only vars extern, but they also have to be
> > > + declared constexpr and "extern constexpr inline info x;" is
> > > + ill-formed. */
> > > + && !consteval_only_p (decl))
> >
> > Would it work to check DECL_THIS_EXTERN instead, so we're complaining about
> > an extern declaration rather than just based on the compiler deciding not to
> > emit?
>
> Sadly, no, we'd give the error for
>
> extern constexpr inline info v2{};
> static_assert(v2 == info{});
>
> where the extern is I think redundant due to [basic.link]/3.2.3.
> EDG and clang++ accept that code too.
>
> Marek
Marek
