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* [Bug libstdc++/70692] No warning when std::function<const int&(...)> binds a reference to a temporary
[not found] <bug-70692-4@http.gcc.gnu.org/bugzilla/>
@ 2021-04-19 10:40 ` redi at gcc dot gnu.org
2021-12-03 19:45 ` pinskia at gcc dot gnu.org
` (4 subsequent siblings)
5 siblings, 0 replies; 6+ messages in thread
From: redi at gcc dot gnu.org @ 2021-04-19 10:40 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70692
Jonathan Wakely <redi at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Assignee|redi at gcc dot gnu.org |unassigned at gcc dot gnu.org
Status|ASSIGNED |NEW
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug libstdc++/70692] No warning when std::function<const int&(...)> binds a reference to a temporary
[not found] <bug-70692-4@http.gcc.gnu.org/bugzilla/>
2021-04-19 10:40 ` [Bug libstdc++/70692] No warning when std::function<const int&(...)> binds a reference to a temporary redi at gcc dot gnu.org
@ 2021-12-03 19:45 ` pinskia at gcc dot gnu.org
2021-12-03 22:12 ` redi at gcc dot gnu.org
` (3 subsequent siblings)
5 siblings, 0 replies; 6+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-12-03 19:45 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70692
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |gcc at hazlewoods dot net
--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
*** Bug 103543 has been marked as a duplicate of this bug. ***
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug libstdc++/70692] No warning when std::function<const int&(...)> binds a reference to a temporary
[not found] <bug-70692-4@http.gcc.gnu.org/bugzilla/>
2021-04-19 10:40 ` [Bug libstdc++/70692] No warning when std::function<const int&(...)> binds a reference to a temporary redi at gcc dot gnu.org
2021-12-03 19:45 ` pinskia at gcc dot gnu.org
@ 2021-12-03 22:12 ` redi at gcc dot gnu.org
2022-02-09 20:04 ` pinskia at gcc dot gnu.org
` (2 subsequent siblings)
5 siblings, 0 replies; 6+ messages in thread
From: redi at gcc dot gnu.org @ 2021-12-03 22:12 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70692
--- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> ---
"A type trait to detect reference binding to temporary"
https://wg21.link/p2255r2 is the current direction to resolve this.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug libstdc++/70692] No warning when std::function<const int&(...)> binds a reference to a temporary
[not found] <bug-70692-4@http.gcc.gnu.org/bugzilla/>
` (2 preceding siblings ...)
2021-12-03 22:12 ` redi at gcc dot gnu.org
@ 2022-02-09 20:04 ` pinskia at gcc dot gnu.org
2022-09-28 23:35 ` cvs-commit at gcc dot gnu.org
2022-09-28 23:38 ` redi at gcc dot gnu.org
5 siblings, 0 replies; 6+ messages in thread
From: pinskia at gcc dot gnu.org @ 2022-02-09 20:04 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70692
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
See Also| |https://gcc.gnu.org/bugzill
| |a/show_bug.cgi?id=104477
--- Comment #6 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Jonathan Wakely from comment #5)
> "A type trait to detect reference binding to temporary"
> https://wg21.link/p2255r2 is the current direction to resolve this.
Which is now recorded as PR 104477.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug libstdc++/70692] No warning when std::function<const int&(...)> binds a reference to a temporary
[not found] <bug-70692-4@http.gcc.gnu.org/bugzilla/>
` (3 preceding siblings ...)
2022-02-09 20:04 ` pinskia at gcc dot gnu.org
@ 2022-09-28 23:35 ` cvs-commit at gcc dot gnu.org
2022-09-28 23:38 ` redi at gcc dot gnu.org
5 siblings, 0 replies; 6+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2022-09-28 23:35 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70692
--- Comment #7 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jonathan Wakely <redi@gcc.gnu.org>:
https://gcc.gnu.org/g:fa9bda3ea4315a7285edbc99323e3fa7885cbbb8
commit r13-2922-gfa9bda3ea4315a7285edbc99323e3fa7885cbbb8
Author: Jonathan Wakely <jwakely@redhat.com>
Date: Tue Sep 27 20:59:05 2022 +0100
libstdc++: Make INVOKE<R> refuse to create dangling references [PR70692]
This is the next part of the library changes from P2255R2. This makes
INVOKE<R> ill-formed if converting the INVOKE expression to R would bind
a reference to a temporary object.
The is_invocable_r trait is now false if the invocation would create a
dangling reference. This is done by adding the dangling check to the
__is_invocable_impl partial specialization used for INVOKE<R>
expressions. This change also slightly simplifies the nothrow checking
recently added to that partial specialization.
This change also removes the is_invocable_r checks from the pre-C++17
implementation of std::__invoke_r, because there is no need for it to be
SFINAE-friendly. None of our C++11 and C++14 uses of INVOKE<R> require
those constraints. The std::function constructor needs to check
is_invocable_r, but that's already done explicitly, so we don't need to
recheck when calling __is_invoke_r in std::function::operator(). The
other uses of std::__is_invoke_r do not need to be constrained and can
just be ill-formed if the INVOKE<R> expression is ill-formed.
libstdc++-v3/ChangeLog:
PR libstdc++/70692
* include/bits/invoke.h [__cplusplus < 201703] (__invoke_r):
Remove is_invocable and is_convertible constraints.
* include/std/type_traits (__is_invocable_impl::_S_conv): Use
non-deduced context for parameter.
(__is_invocable_impl::_S_test): Remove _Check_noex template
parameter and use deduced noexcept value in its place. Add bool
parameter to detect dangling references.
(__is_invocable_impl::type): Adjust call to _S_test to avoid
deducing unnecessary noexcept property..
(__is_invocable_impl::__nothrow_type): Rename to ...
(__is_invocable_impl::__nothrow_conv): ... this. Adjust call
to _S_test to deduce noexcept property.
* testsuite/20_util/bind/dangling_ref.cc: New test.
* testsuite/20_util/function/cons/70692.cc: New test.
* testsuite/20_util/function_objects/invoke/dangling_ref.cc:
New test.
* testsuite/20_util/is_invocable/dangling_ref.cc: New test.
* testsuite/30_threads/packaged_task/cons/dangling_ref.cc:
New test.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug libstdc++/70692] No warning when std::function<const int&(...)> binds a reference to a temporary
[not found] <bug-70692-4@http.gcc.gnu.org/bugzilla/>
` (4 preceding siblings ...)
2022-09-28 23:35 ` cvs-commit at gcc dot gnu.org
@ 2022-09-28 23:38 ` redi at gcc dot gnu.org
5 siblings, 0 replies; 6+ messages in thread
From: redi at gcc dot gnu.org @ 2022-09-28 23:38 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70692
Jonathan Wakely <redi at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
Target Milestone|--- |13.0
Resolution|--- |FIXED
--- Comment #8 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Fixed for GCC 13 by implementing the changes from https://wg21.link/P2255R2
The original example is now ill-formed.
^ permalink raw reply [flat|nested] 6+ messages in thread
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[not found] <bug-70692-4@http.gcc.gnu.org/bugzilla/>
2021-04-19 10:40 ` [Bug libstdc++/70692] No warning when std::function<const int&(...)> binds a reference to a temporary redi at gcc dot gnu.org
2021-12-03 19:45 ` pinskia at gcc dot gnu.org
2021-12-03 22:12 ` redi at gcc dot gnu.org
2022-02-09 20:04 ` pinskia at gcc dot gnu.org
2022-09-28 23:35 ` cvs-commit at gcc dot gnu.org
2022-09-28 23:38 ` redi at gcc dot gnu.org
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