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* [Bug c++/101181] New: ICE when using an alias template
@ 2021-06-23 18:02 webrown.cpp at gmail dot com
2021-06-30 19:25 ` [Bug c++/101181] [11/12 Regression] " mpolacek at gcc dot gnu.org
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: webrown.cpp at gmail dot com @ 2021-06-23 18:02 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101181
Bug ID: 101181
Summary: ICE when using an alias template
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: webrown.cpp at gmail dot com
Target Milestone: ---
The following program produces "Segmentation fault: 11 signal terminated
program cc1plus" when compiled with flags
-std=c++23 -fmodules-ts -pedantic-errors -O0 -c
using gcc trunk version
(Homebrew GCC HEAD-da13e4e_1) 12.0.0 20210623 (experimental)
template< class T
, bool = requires { typename T::pointer; }
>
struct p { using type = void; };
template< class T >
struct p<T, true> { using type = T::pointer; };
template< class T > using P = typename p<T>::type;
Without the final alias template, all seems well.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c++/101181] [11/12 Regression] ICE when using an alias template
2021-06-23 18:02 [Bug c++/101181] New: ICE when using an alias template webrown.cpp at gmail dot com
@ 2021-06-30 19:25 ` mpolacek at gcc dot gnu.org
2021-07-08 0:10 ` ppalka at gcc dot gnu.org
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2021-06-30 19:25 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101181
Marek Polacek <mpolacek at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Ever confirmed|0 |1
Last reconfirmed| |2021-06-30
CC| |mpolacek at gcc dot gnu.org,
| |ppalka at gcc dot gnu.org
Summary|ICE when using an alias |[11/12 Regression] ICE when
|template |using an alias template
Target Milestone|--- |11.2
Priority|P3 |P2
--- Comment #1 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Confirmed, started with r11-3261.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c++/101181] [11/12 Regression] ICE when using an alias template
2021-06-23 18:02 [Bug c++/101181] New: ICE when using an alias template webrown.cpp at gmail dot com
2021-06-30 19:25 ` [Bug c++/101181] [11/12 Regression] " mpolacek at gcc dot gnu.org
@ 2021-07-08 0:10 ` ppalka at gcc dot gnu.org
2021-07-09 14:22 ` cvs-commit at gcc dot gnu.org
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: ppalka at gcc dot gnu.org @ 2021-07-08 0:10 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101181
Patrick Palka <ppalka at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Assignee|unassigned at gcc dot gnu.org |ppalka at gcc dot gnu.org
Status|NEW |ASSIGNED
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c++/101181] [11/12 Regression] ICE when using an alias template
2021-06-23 18:02 [Bug c++/101181] New: ICE when using an alias template webrown.cpp at gmail dot com
2021-06-30 19:25 ` [Bug c++/101181] [11/12 Regression] " mpolacek at gcc dot gnu.org
2021-07-08 0:10 ` ppalka at gcc dot gnu.org
@ 2021-07-09 14:22 ` cvs-commit at gcc dot gnu.org
2021-07-13 14:03 ` cvs-commit at gcc dot gnu.org
2021-07-13 14:10 ` ppalka at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2021-07-09 14:22 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101181
--- Comment #2 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Patrick Palka <ppalka@gcc.gnu.org>:
https://gcc.gnu.org/g:2c699fd29829cd6115f78238dab7cab74f0a5009
commit r12-2222-g2c699fd29829cd6115f78238dab7cab74f0a5009
Author: Patrick Palka <ppalka@redhat.com>
Date: Fri Jul 9 10:20:25 2021 -0400
c++: requires-expr with dependent extra args [PR101181]
Here we're crashing ultimately because the mechanism for delaying
substitution into a requires-expression (and constexpr if and pack
expansions) doesn't expect to see dependent args. But we end up
capturing dependent args here during substitution into the default
template argument as part of coerce_template_parms for the dependent
specialization p<T>.
This patch enables the commented out code in add_extra_args for handling
this situation. This isn't needed for pack expansions (as the
accompanying comment points out), and it doesn't seem strictly necessary
for constexpr if either, but for requires-expressions delaying even
dependent substitution is important for ensuring we don't evaluate
requirements out of order.
It turns out we also need to make a copy of the arguments when capturing
them so that coerce_template_parms doesn't later add to them and form an
unexpected cycle (REQUIRES_EXPR_EXTRA_ARGS (t) would indirectly point to
t).
We also need to make tsubst_template_args handle missing template
arguments, since the arguments we capture from coerce_template_parms
and are incomplete at that point.
PR c++/101181
gcc/cp/ChangeLog:
* constraint.cc (tsubst_requires_expr): Pass complain/in_decl to
add_extra_args.
* cp-tree.h (add_extra_args): Add complain/in_decl parameters.
* pt.c (build_extra_args): Make a copy of args.
(add_extra_args): Add complain/in_decl parameters. Enable the
code for handling the case where the extra arguments are
dependent.
(tsubst_pack_expansion): Pass complain/in_decl to
add_extra_args.
(tsubst_template_args): Handle missing template arguments.
(tsubst_expr) <case IF_STMT>: Pass complain/in_decl to
add_extra_args.
gcc/testsuite/ChangeLog:
* g++.dg/cpp2a/concepts-requires26.C: New test.
* g++.dg/cpp2a/lambda-uneval16.C: New test.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c++/101181] [11/12 Regression] ICE when using an alias template
2021-06-23 18:02 [Bug c++/101181] New: ICE when using an alias template webrown.cpp at gmail dot com
` (2 preceding siblings ...)
2021-07-09 14:22 ` cvs-commit at gcc dot gnu.org
@ 2021-07-13 14:03 ` cvs-commit at gcc dot gnu.org
2021-07-13 14:10 ` ppalka at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2021-07-13 14:03 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101181
--- Comment #3 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-11 branch has been updated by Patrick Palka
<ppalka@gcc.gnu.org>:
https://gcc.gnu.org/g:63566075309907ca807c1c6cef57bf19f4602825
commit r11-8734-g63566075309907ca807c1c6cef57bf19f4602825
Author: Patrick Palka <ppalka@redhat.com>
Date: Fri Jul 9 10:20:25 2021 -0400
c++: requires-expr with dependent extra args [PR101181]
Here we're crashing ultimately because the mechanism for delaying
substitution into a requires-expression (and constexpr if and pack
expansions) doesn't expect to see dependent args. But we end up
capturing dependent args here during substitution into the default
template argument as part of coerce_template_parms for the dependent
specialization p<T>.
This patch enables the commented out code in add_extra_args for handling
this situation. This isn't needed for pack expansions (as the
accompanying comment points out), and it doesn't seem strictly necessary
for constexpr if either, but for requires-expressions delaying even
dependent substitution is important for ensuring we don't evaluate
requirements out of order.
It turns out we also need to make a copy of the arguments when capturing
them so that coerce_template_parms doesn't later add to them and form an
unexpected cycle (REQUIRES_EXPR_EXTRA_ARGS (t) would indirectly point to
t).
We also need to make tsubst_template_args handle missing template
arguments, since the arguments we capture from coerce_template_parms
and are incomplete at that point.
PR c++/101181
gcc/cp/ChangeLog:
* constraint.cc (tsubst_requires_expr): Pass complain/in_decl to
add_extra_args.
* cp-tree.h (add_extra_args): Add complain/in_decl parameters.
* pt.c (build_extra_args): Make a copy of args.
(add_extra_args): Add complain/in_decl parameters. Enable the
code for handling the case where the extra arguments are
dependent.
(tsubst_pack_expansion): Pass complain/in_decl to
add_extra_args.
(tsubst_template_args): Handle missing template arguments.
(tsubst_expr) <case IF_STMT>: Pass complain/in_decl to
add_extra_args.
gcc/testsuite/ChangeLog:
* g++.dg/cpp2a/concepts-requires26.C: New test.
* g++.dg/cpp2a/lambda-uneval16.C: New test.
(cherry picked from commit 2c699fd29829cd6115f78238dab7cab74f0a5009)
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c++/101181] [11/12 Regression] ICE when using an alias template
2021-06-23 18:02 [Bug c++/101181] New: ICE when using an alias template webrown.cpp at gmail dot com
` (3 preceding siblings ...)
2021-07-13 14:03 ` cvs-commit at gcc dot gnu.org
@ 2021-07-13 14:10 ` ppalka at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: ppalka at gcc dot gnu.org @ 2021-07-13 14:10 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101181
Patrick Palka <ppalka at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Resolution|--- |FIXED
--- Comment #4 from Patrick Palka <ppalka at gcc dot gnu.org> ---
Fixed for GCC 11.2/12
^ permalink raw reply [flat|nested] 6+ messages in thread
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2021-06-23 18:02 [Bug c++/101181] New: ICE when using an alias template webrown.cpp at gmail dot com
2021-06-30 19:25 ` [Bug c++/101181] [11/12 Regression] " mpolacek at gcc dot gnu.org
2021-07-08 0:10 ` ppalka at gcc dot gnu.org
2021-07-09 14:22 ` cvs-commit at gcc dot gnu.org
2021-07-13 14:03 ` cvs-commit at gcc dot gnu.org
2021-07-13 14:10 ` ppalka at gcc dot gnu.org
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