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* [Bug c++/99524] New: initializer_list storage considered a temporary when accessed through NTTP
@ 2021-03-10 18:08 johelegp at gmail dot com
2023-11-16 0:49 ` [Bug c++/99524] " arthur.j.odwyer at gmail dot com
2023-11-16 0:51 ` johelegp at gmail dot com
0 siblings, 2 replies; 3+ messages in thread
From: johelegp at gmail dot com @ 2021-03-10 18:08 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99524
Bug ID: 99524
Summary: initializer_list storage considered a temporary when
accessed through NTTP
Product: gcc
Version: 11.0
URL: https://godbolt.org/z/aWGr3P
Status: UNCONFIRMED
Keywords: rejects-valid
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: johelegp at gmail dot com
CC: johelegp at gmail dot com
Target Milestone: ---
See https://godbolt.org/z/aWGr3P.
```C++
#include<initializer_list>
constexpr std::initializer_list<bool>il{true};
template<const bool*B>constexpr bool front=B[0];
static_assert(front<il.begin()>);
```
https://timsong-cpp.github.io/cppwp/n4861/dcl.init.list#5 explains its storage.
https://timsong-cpp.github.io/cppwp/n4861/dcl.init.list#6 explains its
lifetime.
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug c++/99524] initializer_list storage considered a temporary when accessed through NTTP
2021-03-10 18:08 [Bug c++/99524] New: initializer_list storage considered a temporary when accessed through NTTP johelegp at gmail dot com
@ 2023-11-16 0:49 ` arthur.j.odwyer at gmail dot com
2023-11-16 0:51 ` johelegp at gmail dot com
1 sibling, 0 replies; 3+ messages in thread
From: arthur.j.odwyer at gmail dot com @ 2023-11-16 0:49 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99524
Arthur O'Dwyer <arthur.j.odwyer at gmail dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |arthur.j.odwyer at gmail dot com
--- Comment #1 from Arthur O'Dwyer <arthur.j.odwyer at gmail dot com> ---
I don't see this as a bug (and indeed Clang/MSVC reject it too). It's okay to
use the address of `il` itself as the value of a template parameter, because we
know a mangleable name for that; but the address of the first element of the
backing array isn't a valid value for a template parameter, because the backing
array is anonymous — it hasn't got a mangleable name — in the
very-new-like-as-of-last-week Standardese, it's a "potentially non-unique
object." The same rejection applies to this example employing a string literal
(the other kind of "potentially non-unique object") in the Standard
post-CWG2753):
constexpr const char *il = "hello world";
template<auto*> constexpr bool front = true;
static_assert(front<&il>); // OK
static_assert(front<&il[0]>); // Reject
So I think this is not-a-bug.
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug c++/99524] initializer_list storage considered a temporary when accessed through NTTP
2021-03-10 18:08 [Bug c++/99524] New: initializer_list storage considered a temporary when accessed through NTTP johelegp at gmail dot com
2023-11-16 0:49 ` [Bug c++/99524] " arthur.j.odwyer at gmail dot com
@ 2023-11-16 0:51 ` johelegp at gmail dot com
1 sibling, 0 replies; 3+ messages in thread
From: johelegp at gmail dot com @ 2023-11-16 0:51 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99524
Johel Ernesto Guerrero Peña <johelegp at gmail dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Resolution|--- |INVALID
Status|UNCONFIRMED |RESOLVED
--- Comment #2 from Johel Ernesto Guerrero Peña <johelegp at gmail dot com> ---
Thank you.
Let's close this then.
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2023-11-16 0:51 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2021-03-10 18:08 [Bug c++/99524] New: initializer_list storage considered a temporary when accessed through NTTP johelegp at gmail dot com
2023-11-16 0:49 ` [Bug c++/99524] " arthur.j.odwyer at gmail dot com
2023-11-16 0:51 ` johelegp at gmail dot com
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