c++: ICE with auto in template arg [PR110065]
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Commit Message
Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
-- >8 --
Here we started crashing with r14-1659 because that removed the
auto checking in cp_parser_template_type_arg which seemed like
dead code. But the attached test shows that the code can still
be reached because cp_parser_type_id_1 checks auto only when
auto_is_implicit_function_template_parm_p is on.
Then I noticed that we're still crashing in C++20, and that ICE
started with r12-4772. So I changed the reemerged check to use
flag_concepts_ts rather than flag_concepts on the basis that
check_auto_in_tmpl_args also checks flag_concepts_ts.
PR c++/110065
gcc/cp/ChangeLog:
* parser.cc (cp_parser_template_type_arg): Add auto checking.
gcc/testsuite/ChangeLog:
* g++.dg/concepts/auto8.C: New test.
* g++.dg/concepts/auto8a.C: New test.
---
gcc/cp/parser.cc | 12 ++++++++++--
gcc/testsuite/g++.dg/concepts/auto8.C | 17 +++++++++++++++++
gcc/testsuite/g++.dg/concepts/auto8a.C | 18 ++++++++++++++++++
3 files changed, 45 insertions(+), 2 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/concepts/auto8.C
create mode 100644 gcc/testsuite/g++.dg/concepts/auto8a.C
base-commit: 731444b3c39e3dc3dd8778f430a38742861dcca1
Comments
On 1/15/24 17:14, Marek Polacek wrote:
> Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk?
OK, thanks.
> -- >8 --
>
> Here we started crashing with r14-1659 because that removed the
> auto checking in cp_parser_template_type_arg which seemed like
> dead code. But the attached test shows that the code can still
> be reached because cp_parser_type_id_1 checks auto only when
> auto_is_implicit_function_template_parm_p is on.
>
> Then I noticed that we're still crashing in C++20, and that ICE
> started with r12-4772. So I changed the reemerged check to use
> flag_concepts_ts rather than flag_concepts on the basis that
> check_auto_in_tmpl_args also checks flag_concepts_ts.
>
> PR c++/110065
>
> gcc/cp/ChangeLog:
>
> * parser.cc (cp_parser_template_type_arg): Add auto checking.
>
> gcc/testsuite/ChangeLog:
>
> * g++.dg/concepts/auto8.C: New test.
> * g++.dg/concepts/auto8a.C: New test.
> ---
> gcc/cp/parser.cc | 12 ++++++++++--
> gcc/testsuite/g++.dg/concepts/auto8.C | 17 +++++++++++++++++
> gcc/testsuite/g++.dg/concepts/auto8a.C | 18 ++++++++++++++++++
> 3 files changed, 45 insertions(+), 2 deletions(-)
> create mode 100644 gcc/testsuite/g++.dg/concepts/auto8.C
> create mode 100644 gcc/testsuite/g++.dg/concepts/auto8a.C
>
> diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc
> index 8ab98cc0c23..e92309b8960 100644
> --- a/gcc/cp/parser.cc
> +++ b/gcc/cp/parser.cc
> @@ -25063,12 +25063,20 @@ cp_parser_type_id (cp_parser *parser, cp_parser_flags flags,
> static tree
> cp_parser_template_type_arg (cp_parser *parser)
> {
> - tree r;
> const char *saved_message = parser->type_definition_forbidden_message;
> parser->type_definition_forbidden_message
> = G_("types may not be defined in template arguments");
> - r = cp_parser_type_id_1 (parser, CP_PARSER_FLAGS_NONE, true, false, NULL);
> + tree r = cp_parser_type_id_1 (parser, CP_PARSER_FLAGS_NONE,
> + /*is_template_arg=*/true,
> + /*is_trailing_return=*/false, nullptr);
> parser->type_definition_forbidden_message = saved_message;
> + /* cp_parser_type_id_1 checks for auto, but only for
> + ->auto_is_implicit_function_template_parm_p. */
> + if (cxx_dialect >= cxx14 && !flag_concepts_ts && type_uses_auto (r))
> + {
> + error ("invalid use of %<auto%> in template argument");
> + r = error_mark_node;
> + }
> return r;
> }
>
> diff --git a/gcc/testsuite/g++.dg/concepts/auto8.C b/gcc/testsuite/g++.dg/concepts/auto8.C
> new file mode 100644
> index 00000000000..f9d98b2ec0f
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/concepts/auto8.C
> @@ -0,0 +1,17 @@
> +// PR c++/110065
> +// { dg-do compile { target c++17 } }
> +
> +template <typename>
> +inline constexpr bool t = false;
> +
> +int
> +f ()
> +{
> + return t<auto(&)(const int*) -> auto&>; // { dg-error "template argument" }
> +}
> +
> +void
> +g ()
> +{
> + t<auto(&)(const int*) -> auto&>; // { dg-error "template argument" }
> +}
> diff --git a/gcc/testsuite/g++.dg/concepts/auto8a.C b/gcc/testsuite/g++.dg/concepts/auto8a.C
> new file mode 100644
> index 00000000000..fc60dc871c2
> --- /dev/null
> +++ b/gcc/testsuite/g++.dg/concepts/auto8a.C
> @@ -0,0 +1,18 @@
> +// PR c++/110065
> +// { dg-do compile { target c++17 } }
> +// { dg-additional-options -fconcepts-ts }
> +
> +template <typename>
> +inline constexpr bool t = false;
> +
> +int
> +f ()
> +{
> + return t<auto(&)(const int*) -> auto&>; // { dg-error "template argument" }
> +}
> +
> +void
> +g ()
> +{
> + t<auto(&)(const int*) -> auto&>; // { dg-error "template argument" }
> +}
>
> base-commit: 731444b3c39e3dc3dd8778f430a38742861dcca1
@@ -25063,12 +25063,20 @@ cp_parser_type_id (cp_parser *parser, cp_parser_flags flags,
static tree
cp_parser_template_type_arg (cp_parser *parser)
{
- tree r;
const char *saved_message = parser->type_definition_forbidden_message;
parser->type_definition_forbidden_message
= G_("types may not be defined in template arguments");
- r = cp_parser_type_id_1 (parser, CP_PARSER_FLAGS_NONE, true, false, NULL);
+ tree r = cp_parser_type_id_1 (parser, CP_PARSER_FLAGS_NONE,
+ /*is_template_arg=*/true,
+ /*is_trailing_return=*/false, nullptr);
parser->type_definition_forbidden_message = saved_message;
+ /* cp_parser_type_id_1 checks for auto, but only for
+ ->auto_is_implicit_function_template_parm_p. */
+ if (cxx_dialect >= cxx14 && !flag_concepts_ts && type_uses_auto (r))
+ {
+ error ("invalid use of %<auto%> in template argument");
+ r = error_mark_node;
+ }
return r;
}
new file mode 100644
@@ -0,0 +1,17 @@
+// PR c++/110065
+// { dg-do compile { target c++17 } }
+
+template <typename>
+inline constexpr bool t = false;
+
+int
+f ()
+{
+ return t<auto(&)(const int*) -> auto&>; // { dg-error "template argument" }
+}
+
+void
+g ()
+{
+ t<auto(&)(const int*) -> auto&>; // { dg-error "template argument" }
+}
new file mode 100644
@@ -0,0 +1,18 @@
+// PR c++/110065
+// { dg-do compile { target c++17 } }
+// { dg-additional-options -fconcepts-ts }
+
+template <typename>
+inline constexpr bool t = false;
+
+int
+f ()
+{
+ return t<auto(&)(const int*) -> auto&>; // { dg-error "template argument" }
+}
+
+void
+g ()
+{
+ t<auto(&)(const int*) -> auto&>; // { dg-error "template argument" }
+}