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* [Bug c++/97712] New: Attribute nodiscard in virtual methods is ignored
@ 2020-11-04 7:21 pacoarjonilla at yahoo dot es
2020-11-04 14:43 ` [Bug c++/97712] " mpolacek at gcc dot gnu.org
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: pacoarjonilla at yahoo dot es @ 2020-11-04 7:21 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97712
Bug ID: 97712
Summary: Attribute nodiscard in virtual methods is ignored
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: pacoarjonilla at yahoo dot es
Target Milestone: ---
The standard attribute [[nodiscard]] is ignored if the function is virtual.
Versions GNU C++ trunk and GNU C++ 10.2 fails to issue a warning on the
following snippet:
>>>>>>>>>>>
struct B {
[[nodiscard]] virtual int f() = 0;
};
struct D : public B {
[[nodiscard]] int f() override {return 1;}
};
int main() {
B * b = new D;
b->f(); // GNU C++ does not warn about discarded value
}
<<<<<<<<<<<<<
Clang does issue a warning appropriately.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c++/97712] Attribute nodiscard in virtual methods is ignored
2020-11-04 7:21 [Bug c++/97712] New: Attribute nodiscard in virtual methods is ignored pacoarjonilla at yahoo dot es
@ 2020-11-04 14:43 ` mpolacek at gcc dot gnu.org
2020-11-04 18:48 ` mpolacek at gcc dot gnu.org
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2020-11-04 14:43 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97712
Marek Polacek <mpolacek at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |mpolacek at gcc dot gnu.org
Last reconfirmed| |2020-11-04
Status|UNCONFIRMED |NEW
Ever confirmed|0 |1
--- Comment #1 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Confirmed.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c++/97712] Attribute nodiscard in virtual methods is ignored
2020-11-04 7:21 [Bug c++/97712] New: Attribute nodiscard in virtual methods is ignored pacoarjonilla at yahoo dot es
2020-11-04 14:43 ` [Bug c++/97712] " mpolacek at gcc dot gnu.org
@ 2020-11-04 18:48 ` mpolacek at gcc dot gnu.org
2020-11-04 18:54 ` jakub at gcc dot gnu.org
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: mpolacek at gcc dot gnu.org @ 2020-11-04 18:48 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97712
--- Comment #2 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Looks like we don't track attributes properly for OBJ_TYPE_REFs in
maybe_warn_nodiscard.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c++/97712] Attribute nodiscard in virtual methods is ignored
2020-11-04 7:21 [Bug c++/97712] New: Attribute nodiscard in virtual methods is ignored pacoarjonilla at yahoo dot es
2020-11-04 14:43 ` [Bug c++/97712] " mpolacek at gcc dot gnu.org
2020-11-04 18:48 ` mpolacek at gcc dot gnu.org
@ 2020-11-04 18:54 ` jakub at gcc dot gnu.org
2020-11-15 3:14 ` pacoarjonilla at yahoo dot es
2021-06-02 10:32 ` redi at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: jakub at gcc dot gnu.org @ 2020-11-04 18:54 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97712
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |jakub at gcc dot gnu.org
--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
[[nodiscard]] is a function attribute rather than function type attribute, so
it really doesn't apply to virtual calls (unless it can be devirtualized
early).
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c++/97712] Attribute nodiscard in virtual methods is ignored
2020-11-04 7:21 [Bug c++/97712] New: Attribute nodiscard in virtual methods is ignored pacoarjonilla at yahoo dot es
` (2 preceding siblings ...)
2020-11-04 18:54 ` jakub at gcc dot gnu.org
@ 2020-11-15 3:14 ` pacoarjonilla at yahoo dot es
2021-06-02 10:32 ` redi at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: pacoarjonilla at yahoo dot es @ 2020-11-15 3:14 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97712
--- Comment #4 from Paco Arjonilla <pacoarjonilla at yahoo dot es> ---
(In reply to Jakub Jelinek from comment #3)
> [[nodiscard]] is a function attribute rather than function type attribute,
> so it really doesn't apply to virtual calls (unless it can be devirtualized
> early).
Is it a bug in GCC or in the C++ standard?
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c++/97712] Attribute nodiscard in virtual methods is ignored
2020-11-04 7:21 [Bug c++/97712] New: Attribute nodiscard in virtual methods is ignored pacoarjonilla at yahoo dot es
` (3 preceding siblings ...)
2020-11-15 3:14 ` pacoarjonilla at yahoo dot es
@ 2021-06-02 10:32 ` redi at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: redi at gcc dot gnu.org @ 2021-06-02 10:32 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97712
Jonathan Wakely <redi at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Resolution|--- |DUPLICATE
Status|NEW |RESOLVED
--- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> ---
.
*** This bug has been marked as a duplicate of bug 84476 ***
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2021-06-02 10:32 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
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2020-11-04 7:21 [Bug c++/97712] New: Attribute nodiscard in virtual methods is ignored pacoarjonilla at yahoo dot es
2020-11-04 14:43 ` [Bug c++/97712] " mpolacek at gcc dot gnu.org
2020-11-04 18:48 ` mpolacek at gcc dot gnu.org
2020-11-04 18:54 ` jakub at gcc dot gnu.org
2020-11-15 3:14 ` pacoarjonilla at yahoo dot es
2021-06-02 10:32 ` redi at gcc dot gnu.org
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