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* [Bug c++/102012] New: GCC accepts any non-bool atomic constraint type
@ 2021-08-22 15:14 hewillk at gmail dot com
2021-08-23 10:05 ` [Bug c++/102012] " redi at gcc dot gnu.org
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: hewillk at gmail dot com @ 2021-08-22 15:14 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102012
Bug ID: 102012
Summary: GCC accepts any non-bool atomic constraint type
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: hewillk at gmail dot com
Target Milestone: ---
struct S { };
template<class T>
concept C = T(true);
decltype(C<int>) x = 0;
decltype(C<double>) y = 0;
decltype(C<const char*>) z = 0;
decltype(C<S>) w = 0;
https://godbolt.org/z/vEEPboYcq
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c++/102012] GCC accepts any non-bool atomic constraint type
2021-08-22 15:14 [Bug c++/102012] New: GCC accepts any non-bool atomic constraint type hewillk at gmail dot com
@ 2021-08-23 10:05 ` redi at gcc dot gnu.org
2021-08-23 14:28 ` ppalka at gcc dot gnu.org
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: redi at gcc dot gnu.org @ 2021-08-23 10:05 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102012
Jonathan Wakely <redi at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Ever confirmed|0 |1
Last reconfirmed| |2021-08-23
Status|UNCONFIRMED |NEW
Blocks| |67491
Referenced Bugs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67491
[Bug 67491] [meta-bug] concepts issues
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c++/102012] GCC accepts any non-bool atomic constraint type
2021-08-22 15:14 [Bug c++/102012] New: GCC accepts any non-bool atomic constraint type hewillk at gmail dot com
2021-08-23 10:05 ` [Bug c++/102012] " redi at gcc dot gnu.org
@ 2021-08-23 14:28 ` ppalka at gcc dot gnu.org
2021-08-23 14:39 ` hewillk at gmail dot com
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: ppalka at gcc dot gnu.org @ 2021-08-23 14:28 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102012
Patrick Palka <ppalka at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |ppalka at gcc dot gnu.org
--- Comment #1 from Patrick Palka <ppalka at gcc dot gnu.org> ---
Hmm, I think this might actually be well-formed according to [temp.names]/9. I
don't see why we'd need to check satisfaction of a concept-id inside decltype
if its type is already prescribed to be bool.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c++/102012] GCC accepts any non-bool atomic constraint type
2021-08-22 15:14 [Bug c++/102012] New: GCC accepts any non-bool atomic constraint type hewillk at gmail dot com
2021-08-23 10:05 ` [Bug c++/102012] " redi at gcc dot gnu.org
2021-08-23 14:28 ` ppalka at gcc dot gnu.org
@ 2021-08-23 14:39 ` hewillk at gmail dot com
2021-08-24 16:56 ` hewillk at gmail dot com
2021-08-24 17:28 ` ppalka at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: hewillk at gmail dot com @ 2021-08-23 14:39 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102012
--- Comment #2 from 康桓瑋 <hewillk at gmail dot com> ---
(In reply to Patrick Palka from comment #1)
> Hmm, I think this might actually be well-formed according to [temp.names]/9.
> I don't see why we'd need to check satisfaction of a concept-id inside
> decltype if its type is already prescribed to be bool.
You are right..
template<class T>
concept C = T{}.foo();
decltype(C<int>) x = 0;
https://godbolt.org/z/zr5qhfGPY
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c++/102012] GCC accepts any non-bool atomic constraint type
2021-08-22 15:14 [Bug c++/102012] New: GCC accepts any non-bool atomic constraint type hewillk at gmail dot com
` (2 preceding siblings ...)
2021-08-23 14:39 ` hewillk at gmail dot com
@ 2021-08-24 16:56 ` hewillk at gmail dot com
2021-08-24 17:28 ` ppalka at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: hewillk at gmail dot com @ 2021-08-24 16:56 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102012
--- Comment #3 from 康桓瑋 <hewillk at gmail dot com> ---
(In reply to Patrick Palka from comment #1)
> Hmm, I think this might actually be well-formed according to [temp.names]/9.
> I don't see why we'd need to check satisfaction of a concept-id inside
> decltype if its type is already prescribed to be bool.
"The standard requires MSVC/Clang's behavior of erroring out." from
https://stackoverflow.com/a/68910627/11638718.
^ permalink raw reply [flat|nested] 6+ messages in thread
* [Bug c++/102012] GCC accepts any non-bool atomic constraint type
2021-08-22 15:14 [Bug c++/102012] New: GCC accepts any non-bool atomic constraint type hewillk at gmail dot com
` (3 preceding siblings ...)
2021-08-24 16:56 ` hewillk at gmail dot com
@ 2021-08-24 17:28 ` ppalka at gcc dot gnu.org
4 siblings, 0 replies; 6+ messages in thread
From: ppalka at gcc dot gnu.org @ 2021-08-24 17:28 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102012
--- Comment #4 from Patrick Palka <ppalka at gcc dot gnu.org> ---
(In reply to 康桓瑋 from comment #3)
> (In reply to Patrick Palka from comment #1)
> > Hmm, I think this might actually be well-formed according to [temp.names]/9.
> > I don't see why we'd need to check satisfaction of a concept-id inside
> > decltype if its type is already prescribed to be bool.
>
> "The standard requires MSVC/Clang's behavior of erroring out." from
> https://stackoverflow.com/a/68910627/11638718.
Yes, evaluation of the concept-id should produce an error during satisfaction
due to the non-bool constraint. But why should we evaluate a concept-id inside
decltype in the first place, when the type of a concept-id is always prescribed
to be bool?
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2021-08-24 17:28 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
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2021-08-22 15:14 [Bug c++/102012] New: GCC accepts any non-bool atomic constraint type hewillk at gmail dot com
2021-08-23 10:05 ` [Bug c++/102012] " redi at gcc dot gnu.org
2021-08-23 14:28 ` ppalka at gcc dot gnu.org
2021-08-23 14:39 ` hewillk at gmail dot com
2021-08-24 16:56 ` hewillk at gmail dot com
2021-08-24 17:28 ` ppalka at gcc dot gnu.org
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