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* [Bug c++/103091] New: Can't jump into scope of a variable with a nontrivial destructor in C++20
@ 2021-11-05 6:29 josephcsible at gmail dot com
2021-11-05 6:51 ` [Bug c++/103091] [DR 2256] " pinskia at gcc dot gnu.org
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: josephcsible at gmail dot com @ 2021-11-05 6:29 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103091
Bug ID: 103091
Summary: Can't jump into scope of a variable with a nontrivial
destructor in C++20
Product: gcc
Version: 11.2.1
Status: UNCONFIRMED
Keywords: rejects-valid
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: josephcsible at gmail dot com
Target Milestone: ---
The C++17 standard says "A program that jumps from a point where a variable
with automatic storage duration is not in scope to a point where it is in scope
is ill-formed unless the variable has scalar type, class type with a trivial
default constructor and a trivial destructor, a cv-qualified version of one of
these types, or an array of one of the preceding types and is declared without
an initializer (11.6)."
The C++20 standard says "A program that jumps from a point where a variable
with automatic storage duration is not in scope to a point where it is in scope
is ill-formed unless the variable has vacuous initialization (6.7.3)." and "A
variable is said to have vacuous initialization if it is default-initialized
and, if it is of class type or a (possibly multi-dimensional) array thereof,
that class type has a trivial default constructor."
Note that the C++17 standard mentions a trivial destructor here, but the C++20
standard does not. Now consider this code:
struct MyStruct {
~MyStruct() {}
};
void foo() {
goto x;
MyStruct s;
x:
return;
}
It's ill-formed in C++17, but fine in C++20. However, we currently reject this
program even with -std=c++20.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c++/103091] [DR 2256] Can't jump into scope of a variable with a nontrivial destructor in C++20
2021-11-05 6:29 [Bug c++/103091] New: Can't jump into scope of a variable with a nontrivial destructor in C++20 josephcsible at gmail dot com
@ 2021-11-05 6:51 ` pinskia at gcc dot gnu.org
2021-11-05 6:52 ` pinskia at gcc dot gnu.org
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-11-05 6:51 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103091
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Blocks| |94404
Alias|cwg2256 |C++DR2256
Summary|Can't jump into scope of a |[DR 2256] Can't jump into
|variable with a nontrivial |scope of a variable with a
|destructor in C++20 |nontrivial destructor in
| |C++20
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#2256
Referenced Bugs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94404
[Bug 94404] [meta-bug] C++ core issues
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c++/103091] [DR 2256] Can't jump into scope of a variable with a nontrivial destructor in C++20
2021-11-05 6:29 [Bug c++/103091] New: Can't jump into scope of a variable with a nontrivial destructor in C++20 josephcsible at gmail dot com
2021-11-05 6:51 ` [Bug c++/103091] [DR 2256] " pinskia at gcc dot gnu.org
@ 2021-11-05 6:52 ` pinskia at gcc dot gnu.org
2021-11-05 8:07 ` redi at gcc dot gnu.org
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-11-05 6:52 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103091
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Last reconfirmed| |2021-11-05
Status|UNCONFIRMED |NEW
Ever confirmed|0 |1
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Confirmed. The C++ spec was changed by DR2256 which is consider CD5.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c++/103091] [DR 2256] Can't jump into scope of a variable with a nontrivial destructor in C++20
2021-11-05 6:29 [Bug c++/103091] New: Can't jump into scope of a variable with a nontrivial destructor in C++20 josephcsible at gmail dot com
2021-11-05 6:51 ` [Bug c++/103091] [DR 2256] " pinskia at gcc dot gnu.org
2021-11-05 6:52 ` pinskia at gcc dot gnu.org
@ 2021-11-05 8:07 ` redi at gcc dot gnu.org
2023-05-07 16:09 ` cvs-commit at gcc dot gnu.org
2023-05-07 16:10 ` ppalka at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: redi at gcc dot gnu.org @ 2021-11-05 8:07 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103091
--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #2)
> which is consider CD5.
That's just a detail of which draft of was included in, which doesn't mean
much. More relevant is that it was approved as a DR so it applies to C++17 (and
earlier) too.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c++/103091] [DR 2256] Can't jump into scope of a variable with a nontrivial destructor in C++20
2021-11-05 6:29 [Bug c++/103091] New: Can't jump into scope of a variable with a nontrivial destructor in C++20 josephcsible at gmail dot com
` (2 preceding siblings ...)
2021-11-05 8:07 ` redi at gcc dot gnu.org
@ 2023-05-07 16:09 ` cvs-commit at gcc dot gnu.org
2023-05-07 16:10 ` ppalka at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2023-05-07 16:09 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103091
--- Comment #4 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:b81785eacef2a28e17e17141fcd334f51640feec
commit r14-563-gb81785eacef2a28e17e17141fcd334f51640feec
Author: Patrick Palka <ppalka@redhat.com>
Date: Sun May 7 12:09:03 2023 -0400
c++: goto entering scope of obj w/ non-trivial dtor [PR103091]
It seems ever since DR 2256 goto is permitted to cross the initialization
of a trivially initialized object with a non-trivial destructor. We
already supported this as an -fpermissive extension, so this patch just
makes us unconditionally support this.
DR 2256
PR c++/103091
gcc/cp/ChangeLog:
* decl.cc (decl_jump_unsafe): Return bool instead of int.
Don't consider TYPE_HAS_NONTRIVIAL_DESTRUCTOR.
(check_previous_goto_1): Simplify now that decl_jump_unsafe
returns bool instead of int.
(check_goto): Likewise.
gcc/testsuite/ChangeLog:
* g++.old-deja/g++.other/init9.C: Don't expect diagnostics for
goto made valid by DR 2256.
* g++.dg/init/goto4.C: New test.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c++/103091] [DR 2256] Can't jump into scope of a variable with a nontrivial destructor in C++20
2021-11-05 6:29 [Bug c++/103091] New: Can't jump into scope of a variable with a nontrivial destructor in C++20 josephcsible at gmail dot com
` (3 preceding siblings ...)
2023-05-07 16:09 ` cvs-commit at gcc dot gnu.org
@ 2023-05-07 16:10 ` ppalka at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: ppalka at gcc dot gnu.org @ 2023-05-07 16:10 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103091
Patrick Palka <ppalka at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
Resolution|--- |FIXED
Target Milestone|--- |14.0
Assignee|unassigned at gcc dot gnu.org |ppalka at gcc dot gnu.org
CC| |ppalka at gcc dot gnu.org
--- Comment #5 from Patrick Palka <ppalka at gcc dot gnu.org> ---
Fixed for GCC 14, thanks for the report.
^ permalink raw reply [flat|nested] 6+ messages in thread
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2021-11-05 6:29 [Bug c++/103091] New: Can't jump into scope of a variable with a nontrivial destructor in C++20 josephcsible at gmail dot com
2021-11-05 6:51 ` [Bug c++/103091] [DR 2256] " pinskia at gcc dot gnu.org
2021-11-05 6:52 ` pinskia at gcc dot gnu.org
2021-11-05 8:07 ` redi at gcc dot gnu.org
2023-05-07 16:09 ` cvs-commit at gcc dot gnu.org
2023-05-07 16:10 ` ppalka at gcc dot gnu.org
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