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* [Bug c++/68888] No Warning when converting an array of a subclass to its parent
[not found] <bug-68888-4@http.gcc.gnu.org/bugzilla/>
@ 2021-08-10 2:30 ` pinskia at gcc dot gnu.org
2021-08-10 10:25 ` redi at gcc dot gnu.org
2021-10-27 5:14 ` egallager at gcc dot gnu.org
2 siblings, 0 replies; 3+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-08-10 2:30 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68888
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |diagnostic
Severity|normal |enhancement
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug c++/68888] No Warning when converting an array of a subclass to its parent
[not found] <bug-68888-4@http.gcc.gnu.org/bugzilla/>
2021-08-10 2:30 ` [Bug c++/68888] No Warning when converting an array of a subclass to its parent pinskia at gcc dot gnu.org
@ 2021-08-10 10:25 ` redi at gcc dot gnu.org
2021-10-27 5:14 ` egallager at gcc dot gnu.org
2 siblings, 0 replies; 3+ messages in thread
From: redi at gcc dot gnu.org @ 2021-08-10 10:25 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68888
Jonathan Wakely <redi at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2021-08-10
Ever confirmed|0 |1
--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
This is undefined behaviour, and should definitely warn (and UBsan should give
an error too).
The implicit conversion sequence of array-to-pointer decay followed by
derived-to-base conversion should warn. If the derived-to-base conversion is
really desired (because no pointer arithmetic will be done on the result) then
users can get a pointer to the first element of the array explicitly, so there
is no implicit decay e.g. any of these would not warn:
go(&bs[0]);
go(&*bs);
go((B*)bs);
go(std::begin(bs));
(of course the code would still have undefined behaviour due to the arithmetic
in go, but it wouldn't warn because there's no implicit decay).
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug c++/68888] No Warning when converting an array of a subclass to its parent
[not found] <bug-68888-4@http.gcc.gnu.org/bugzilla/>
2021-08-10 2:30 ` [Bug c++/68888] No Warning when converting an array of a subclass to its parent pinskia at gcc dot gnu.org
2021-08-10 10:25 ` redi at gcc dot gnu.org
@ 2021-10-27 5:14 ` egallager at gcc dot gnu.org
2 siblings, 0 replies; 3+ messages in thread
From: egallager at gcc dot gnu.org @ 2021-10-27 5:14 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68888
Eric Gallager <egallager at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |egallager at gcc dot gnu.org
--- Comment #2 from Eric Gallager <egallager at gcc dot gnu.org> ---
Any ideas for a proposed name for the flag that would control this warning?
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2021-10-27 5:14 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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[not found] <bug-68888-4@http.gcc.gnu.org/bugzilla/>
2021-08-10 2:30 ` [Bug c++/68888] No Warning when converting an array of a subclass to its parent pinskia at gcc dot gnu.org
2021-08-10 10:25 ` redi at gcc dot gnu.org
2021-10-27 5:14 ` egallager at gcc dot gnu.org
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