On Mon, Feb 11, 2019 at 01:43:36PM -0500, Jason Merrill wrote:
> On 2/7/19 6:02 PM, Marek Polacek wrote:
> > Since r268321 we can call digest_init even in a template, when the compound
> > literal isn't instantiation-dependent.
>
> Right. And since digest_init modifies the CONSTRUCTOR in place, that means
> the template trees are digested rather than the original parse trees that we
> try to use. If we're going to use digest_init, we should probably save
> another CONSTRUCTOR with the original trees.
I tried unsharing the constructor and even its contents but only then did I
realize that this cannot work. It's not digest_init that adds the problematic
INDIRECT_REF via convert_from_reference, it's instantiate_pending_templates
-> tsubst_expr -> ... -> finish_non_static_data_member.
So the problem isn't sharing the contents of the CONSTRUCTOR, but rather what
finish_non_static_data_member does with the
{.r=(struct R &) (struct R *) ((struct S *) this)->r}
expression. The same problem would appear even before r268321 changes if we
called tsubst_* twice on the CONSTRUCTOR above.
Do you still think digest_init and/or finish_compound_literal need tweaking?
Marek
