On Wed, Jul 22, 2026 at 12:39:36PM -0400, Jason Merrill wrote:
> On 7/22/26 8:54 AM, Jakub Jelinek wrote:
> > On Mon, Jul 20, 2026 at 05:25:19PM -0400, Jason Merrill wrote:
> > > > + if (ANON_AGGR_TYPE_P (type))
> > > > + {
> > > > + /* [class.union.anon]/1: Each object of such an unnamed type
> > > > shall be
> > > > + such an unnamed object. */
> > > > + auto_diagnostic_group d;
> > > > + location_t aloc
> > > > + = DECL_SOURCE_LOCATION (TYPE_MAIN_DECL (TYPE_MAIN_VARIANT
> > > > (type)));
> > > > + if (decl && VAR_P (decl) && DECL_NAME (decl) == NULL_TREE)
> > > > + ;
> > >
> > > This could use a comment about why this doesn't allow temporaries.
> >
> > Well, there is a comment a few lines above which includes the (admittedly
> > bad) CWG3130 wording, so anything that can construct an object is considered
> > bad except for the namespace scope anonymous union declaring an unnamed
> > variable. Added ANON_UNION_TYPE_P test to the condition and added a comment
> > why is that case allowed.
>
> Sorry for the confusion; I meant, what prevents the above code from wrongly
> allowing temporaries, which are also represented as variables with null
> DECL_NAME? It seems they are handled earlier somewhere.
For temporaries the function is called with !decl from what I can see.
Jakub
