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From: "jakub at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/107532] [13 Regression] -Werror=dangling-reference false positives in libcamera-0.0.1
Date: Tue, 24 Jan 2023 17:38:26 +0000	[thread overview]
Message-ID: <bug-107532-4-MZXNXD6UFD@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-107532-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107532

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Yeah, without analyzing what the function call (constructor in this case)
actually does
hard to say whether the warning is ok or not.
Maybe some heuristics based on the types?
The reference in question is const Plane &, so see if the reference could bind
to some member of the class that is destructed at the end of the statement
(Ref<Plane>) or the class itself?
Even with that there can be false positives and false negatives,
e.g. the to be destructed temporary could contain a pointer to a heap allocated
Plane and return a reference to that and then deallocate it in the destructor
(it would then be a dangling reference that with the change wouldn't be warned
about), or
on the other side, e.g. if the possibly dangling reference is const Whatever &
and the temporary is Whatever, it might be likely that the reference is to the
temporary, but it could be just a value of some member of it that would happen
to have that type.

  parent reply	other threads:[~2023-01-24 17:38 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-05  5:48 [Bug c++/107532] New: " slyfox at gcc dot gnu.org
2022-11-05 10:58 ` [Bug c++/107532] " rguenth at gcc dot gnu.org
2022-11-11 20:27 ` mpolacek at gcc dot gnu.org
2022-11-21 10:20 ` marxin at gcc dot gnu.org
2022-12-23  8:28 ` marxin at gcc dot gnu.org
2023-01-13 12:39 ` rguenth at gcc dot gnu.org
2023-01-16 16:43 ` mpolacek at gcc dot gnu.org
2023-01-24 17:38 ` jakub at gcc dot gnu.org [this message]
2023-01-24 17:41 ` mpolacek at gcc dot gnu.org
2023-01-24 17:44 ` jakub at gcc dot gnu.org
2023-01-24 17:50 ` mpolacek at gcc dot gnu.org
2023-02-01 14:44 ` pobrn at protonmail dot com
2023-02-14 13:31 ` ecurtin at redhat dot com
2023-02-14 13:45 ` mpolacek at gcc dot gnu.org
2023-03-07 16:11 ` cvs-commit at gcc dot gnu.org
2023-03-07 16:11 ` mpolacek at gcc dot gnu.org
2023-03-08 11:00 ` marxin at gcc dot gnu.org
2023-03-09 11:47 ` marxin at gcc dot gnu.org
2023-03-10 16:46 ` mpolacek at gcc dot gnu.org
2023-03-10 16:52 ` redi at gcc dot gnu.org
2023-03-10 17:02 ` pobrn at protonmail dot com
2023-03-10 17:17 ` mpolacek at gcc dot gnu.org
2023-03-10 17:18 ` mpolacek at gcc dot gnu.org
2023-03-12 10:49 ` eike@sf-mail.de
2023-03-12 13:37 ` flast at flast dot jp
2023-03-13 15:21 ` cvs-commit at gcc dot gnu.org
2023-03-13 15:53 ` mpolacek at gcc dot gnu.org
2023-03-14 23:09 ` flast at flast dot jp
2023-03-16 15:51 ` mpolacek at gcc dot gnu.org
2023-03-16 16:24 ` mpolacek at gcc dot gnu.org
2023-03-23 13:32 ` cvs-commit at gcc dot gnu.org
2023-03-23 13:33 ` mpolacek at gcc dot gnu.org
2023-03-23 15:22 ` gcc-bugzilla at al42and dot me
2023-04-11 16:09 ` gnu.ojxq8 at dralias dot com
2023-04-12 19:46 ` gnu.ojxq8 at dralias dot com
2023-04-12 19:49 ` mpolacek at gcc dot gnu.org
2023-04-27 22:29 ` cuzdav at gmail dot com
2023-06-12  3:25 ` boris at kolpackov dot net
2023-06-12 16:27 ` mpolacek at gcc dot gnu.org

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