From: Jason Merrill <jason@redhat.com>
To: Patrick Palka <ppalka@redhat.com>, gcc-patches@gcc.gnu.org
Subject: Re: [PATCH] c++: deducing empty type vs non-type argument pack
Date: Tue, 18 Jul 2023 12:26:06 -0400 [thread overview]
Message-ID: <85247a8e-1610-1aad-cc09-0b6a7aa102cc@redhat.com> (raw)
In-Reply-To: <20230718151807.665487-1-ppalka@redhat.com>
On 7/18/23 11:18, Patrick Palka wrote:
> Bootstrapped and regtested on x86_64-pc-linux-gnu, does this look OK for
> trunk? Also verified by way of gcc_assert that we never see
> TEMPLATE_PARM_INDEX here.
OK.
> -- >8 --
>
> Within a template parameter list, a non-type template parameter pack is
> represented as a PARM_DECL. But in a couple of spots where we need to
> deduce an empty argument pack, we test for TEMPLATE_PARM_INDEX (within a
> template parameter list) instead of for PARM_DECL, which means we end up
> using TYPE_ARGUMENT_PACK even in the non-type case. This patch fixes
> this (seemingly harmless) bug.
>
> gcc/cp/ChangeLog:
>
> * pt.cc (type_unification_real): Test for PARM_DECL instead
> of TEMPLATE_PARM_INDEX to distinguish a type vs non-type
> template parameter pack.
> (type_targs_deducible_from): Likewise.
> ---
> gcc/cp/pt.cc | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc
> index 3987ffc509a..d342ab5929a 100644
> --- a/gcc/cp/pt.cc
> +++ b/gcc/cp/pt.cc
> @@ -23345,7 +23345,7 @@ type_unification_real (tree tparms,
> {
> tree arg;
>
> - if (TREE_CODE (tparm) == TEMPLATE_PARM_INDEX)
> + if (TREE_CODE (tparm) == PARM_DECL)
> {
> arg = make_node (NONTYPE_ARGUMENT_PACK);
> TREE_CONSTANT (arg) = 1;
> @@ -30369,7 +30369,7 @@ type_targs_deducible_from (tree tmpl, tree type)
> if (template_parameter_pack_p (tparm))
> {
> tree arg;
> - if (TREE_CODE (tparm) == TEMPLATE_PARM_INDEX)
> + if (TREE_CODE (tparm) == PARM_DECL)
> {
> arg = make_node (NONTYPE_ARGUMENT_PACK);
> TREE_CONSTANT (arg) = 1;
prev parent reply other threads:[~2023-07-18 16:26 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-18 15:18 Patrick Palka
2023-07-18 16:26 ` Jason Merrill [this message]
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