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* [Bug c++/112410] New: error when auto(x) is used in a variable initializer
@ 2023-11-06 16:27 vanyacpp at gmail dot com
2023-11-06 16:34 ` [Bug c++/112410] " mpolacek at gcc dot gnu.org
` (6 more replies)
0 siblings, 7 replies; 8+ messages in thread
From: vanyacpp at gmail dot com @ 2023-11-06 16:27 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112410
Bug ID: 112410
Summary: error when auto(x) is used in a variable initializer
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: vanyacpp at gmail dot com
Target Milestone: ---
int x = auto(42); // OK
int y(auto(42)); // error
On the second line GCC -std=c++23 gives an error:
error: non-function 'y' declared as implicit template
I believe the code is correct and should compile without errors.
^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug c++/112410] error when auto(x) is used in a variable initializer
2023-11-06 16:27 [Bug c++/112410] New: error when auto(x) is used in a variable initializer vanyacpp at gmail dot com
@ 2023-11-06 16:34 ` mpolacek at gcc dot gnu.org
2023-11-06 16:37 ` pinskia at gcc dot gnu.org
` (5 subsequent siblings)
6 siblings, 0 replies; 8+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2023-11-06 16:34 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112410
Marek Polacek <mpolacek at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Ever confirmed|0 |1
CC| |mpolacek at gcc dot gnu.org
Last reconfirmed| |2023-11-06
Status|UNCONFIRMED |NEW
--- Comment #1 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
I think you're right. Same for
int z(auto{42});
^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug c++/112410] error when auto(x) is used in a variable initializer
2023-11-06 16:27 [Bug c++/112410] New: error when auto(x) is used in a variable initializer vanyacpp at gmail dot com
2023-11-06 16:34 ` [Bug c++/112410] " mpolacek at gcc dot gnu.org
@ 2023-11-06 16:37 ` pinskia at gcc dot gnu.org
2023-11-06 17:16 ` mpolacek at gcc dot gnu.org
` (4 subsequent siblings)
6 siblings, 0 replies; 8+ messages in thread
From: pinskia at gcc dot gnu.org @ 2023-11-06 16:37 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112410
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Confirmed.
Looks like GCC is messing the Most vexing parse here.
^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug c++/112410] error when auto(x) is used in a variable initializer
2023-11-06 16:27 [Bug c++/112410] New: error when auto(x) is used in a variable initializer vanyacpp at gmail dot com
2023-11-06 16:34 ` [Bug c++/112410] " mpolacek at gcc dot gnu.org
2023-11-06 16:37 ` pinskia at gcc dot gnu.org
@ 2023-11-06 17:16 ` mpolacek at gcc dot gnu.org
2023-11-16 3:24 ` cvs-commit at gcc dot gnu.org
` (3 subsequent siblings)
6 siblings, 0 replies; 8+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2023-11-06 17:16 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112410
Marek Polacek <mpolacek at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |ASSIGNED
Assignee|unassigned at gcc dot gnu.org |mpolacek at gcc dot gnu.org
--- Comment #3 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Part of the problem seems to be that fully_implicit_function_template_p is set.
I'd like to poke more.
^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug c++/112410] error when auto(x) is used in a variable initializer
2023-11-06 16:27 [Bug c++/112410] New: error when auto(x) is used in a variable initializer vanyacpp at gmail dot com
` (2 preceding siblings ...)
2023-11-06 17:16 ` mpolacek at gcc dot gnu.org
@ 2023-11-16 3:24 ` cvs-commit at gcc dot gnu.org
2023-11-16 3:25 ` mpolacek at gcc dot gnu.org
` (2 subsequent siblings)
6 siblings, 0 replies; 8+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2023-11-16 3:24 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112410
--- Comment #4 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The trunk branch has been updated by Marek Polacek <mpolacek@gcc.gnu.org>:
https://gcc.gnu.org/g:70060dadfbf0d0af5f4cab5f3aff3223a4523606
commit r14-5514-g70060dadfbf0d0af5f4cab5f3aff3223a4523606
Author: Marek Polacek <polacek@redhat.com>
Date: Thu Nov 9 12:25:25 2023 -0500
c++: fix parsing with auto(x) [PR112410]
Here we are wrongly parsing
int y(auto(42));
which uses the C++23 cast-to-prvalue feature, and initializes y to 42.
However, we were treating the auto as an implicit template parameter.
Fixing the auto{42} case is easy, but when auto is followed by a (,
I found the fix to be much more involved. For instance, we cannot
use cp_parser_expression, because that can give hard errors. It's
also necessary to disambiguate 'auto(i)' as 'auto i', not a cast.
auto(), auto(int), auto(f)(int), auto(*), auto(i[]), auto(...), etc.
are all function declarations.
This patch rectifies that by undoing the implicit function template
modification. In the test above, we should notice that the parameter
list is ill-formed, and since we've synthesized an implicit template
parameter, we undo it by calling abort_fully_implicit_template. Then,
we'll parse the "(auto(42))" as an initializer.
PR c++/112410
gcc/cp/ChangeLog:
* parser.cc (cp_parser_direct_declarator): Maybe call
abort_fully_implicit_template if it turned out the parameter list
was
ill-formed.
gcc/testsuite/ChangeLog:
* g++.dg/cpp23/auto-fncast13.C: New test.
* g++.dg/cpp23/auto-fncast14.C: New test.
^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug c++/112410] error when auto(x) is used in a variable initializer
2023-11-06 16:27 [Bug c++/112410] New: error when auto(x) is used in a variable initializer vanyacpp at gmail dot com
` (3 preceding siblings ...)
2023-11-16 3:24 ` cvs-commit at gcc dot gnu.org
@ 2023-11-16 3:25 ` mpolacek at gcc dot gnu.org
2023-12-12 0:37 ` cvs-commit at gcc dot gnu.org
2023-12-12 0:38 ` mpolacek at gcc dot gnu.org
6 siblings, 0 replies; 8+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2023-11-16 3:25 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112410
--- Comment #5 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Fixed on trunk so far; I want to fix it in 13 too.
^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug c++/112410] error when auto(x) is used in a variable initializer
2023-11-06 16:27 [Bug c++/112410] New: error when auto(x) is used in a variable initializer vanyacpp at gmail dot com
` (4 preceding siblings ...)
2023-11-16 3:25 ` mpolacek at gcc dot gnu.org
@ 2023-12-12 0:37 ` cvs-commit at gcc dot gnu.org
2023-12-12 0:38 ` mpolacek at gcc dot gnu.org
6 siblings, 0 replies; 8+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2023-12-12 0:37 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112410
--- Comment #6 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-13 branch has been updated by Marek Polacek
<mpolacek@gcc.gnu.org>:
https://gcc.gnu.org/g:60979215517629400902938b1c5666f97d0653cf
commit r13-8147-g60979215517629400902938b1c5666f97d0653cf
Author: Marek Polacek <polacek@redhat.com>
Date: Thu Nov 9 12:25:25 2023 -0500
c++: fix parsing with auto(x) [PR112410]
Here we are wrongly parsing
int y(auto(42));
which uses the C++23 cast-to-prvalue feature, and initializes y to 42.
However, we were treating the auto as an implicit template parameter.
Fixing the auto{42} case is easy, but when auto is followed by a (,
I found the fix to be much more involved. For instance, we cannot
use cp_parser_expression, because that can give hard errors. It's
also necessary to disambiguate 'auto(i)' as 'auto i', not a cast.
auto(), auto(int), auto(f)(int), auto(*), auto(i[]), auto(...), etc.
are all function declarations.
This patch rectifies that by undoing the implicit function template
modification. In the test above, we should notice that the parameter
list is ill-formed, and since we've synthesized an implicit template
parameter, we undo it by calling abort_fully_implicit_template. Then,
we'll parse the "(auto(42))" as an initializer.
PR c++/112410
gcc/cp/ChangeLog:
* parser.cc (cp_parser_direct_declarator): Maybe call
abort_fully_implicit_template if it turned out the parameter list
was
ill-formed.
gcc/testsuite/ChangeLog:
* g++.dg/cpp23/auto-fncast13.C: New test.
* g++.dg/cpp23/auto-fncast14.C: New test.
(cherry picked from commit 70060dadfbf0d0af5f4cab5f3aff3223a4523606)
^ permalink raw reply [flat|nested] 8+ messages in thread
* [Bug c++/112410] error when auto(x) is used in a variable initializer
2023-11-06 16:27 [Bug c++/112410] New: error when auto(x) is used in a variable initializer vanyacpp at gmail dot com
` (5 preceding siblings ...)
2023-12-12 0:37 ` cvs-commit at gcc dot gnu.org
@ 2023-12-12 0:38 ` mpolacek at gcc dot gnu.org
6 siblings, 0 replies; 8+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2023-12-12 0:38 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112410
Marek Polacek <mpolacek at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Resolution|--- |FIXED
--- Comment #7 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Fixed.
^ permalink raw reply [flat|nested] 8+ messages in thread
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2023-11-06 16:27 [Bug c++/112410] New: error when auto(x) is used in a variable initializer vanyacpp at gmail dot com
2023-11-06 16:34 ` [Bug c++/112410] " mpolacek at gcc dot gnu.org
2023-11-06 16:37 ` pinskia at gcc dot gnu.org
2023-11-06 17:16 ` mpolacek at gcc dot gnu.org
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