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* [Bug c++/103183] New: ind[arr] produces an lvalue when arr is an array xvalue
@ 2021-11-11 8:38 de34 at live dot cn
2021-11-11 9:56 ` [Bug c++/103183] " pinskia at gcc dot gnu.org
` (5 more replies)
0 siblings, 6 replies; 7+ messages in thread
From: de34 at live dot cn @ 2021-11-11 8:38 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103183
Bug ID: 103183
Summary: ind[arr] produces an lvalue when arr is an array
xvalue
Product: gcc
Version: 10.1.0
Status: UNCONFIRMED
Keywords: accepts-invalid, rejects-valid
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: de34 at live dot cn
Target Milestone: ---
With gcc 10 and later versions, the following program compiles in C++11/14
modes, but fails to compile in C++17 and later modes. It compiles in C++17 and
later modes if "int&&" is replaced with "int&" (which is wrong according to
[expr.sub]/2).
#include <type_traits>
#include <utility>
int main()
{
int arr[]{0};
static_assert(std::is_same<decltype(0[std::move(arr)]), int&&>::value, "");
}
It seems that arr[ind] doesn't suffer from this bug.
Gcc 9 correctly produced an xvalue in this case.
wandbox links (rejected valid code):
gcc 12.0 (-std=c++17): https://wandbox.org/permlink/HvNaq9T4J7oeYflt
gcc 12.0 (-std=c++14): https://wandbox.org/permlink/S3dhGvKr3aD5OeOW
gcc 10.1 (-std=c++17): https://wandbox.org/permlink/NzqYCtytSUW4oZjR
gcc 10.1 (-std=c++14): https://wandbox.org/permlink/LviIophRujplHx6o
gcc 9.3 (-std=c++17): https://wandbox.org/permlink/JkCQHBdc3xqDSG9s
wandbox links (accepted invalid code, with "int&&" replaced with "int&"):
gcc 12.0 (-std=c++17): https://wandbox.org/permlink/JkCQHBdc3xqDSG9s
gcc 10.1 (-std=c++17): https://wandbox.org/permlink/Yr3Vl2mbeDzGi02v
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c++/103183] ind[arr] produces an lvalue when arr is an array xvalue
2021-11-11 8:38 [Bug c++/103183] New: ind[arr] produces an lvalue when arr is an array xvalue de34 at live dot cn
@ 2021-11-11 9:56 ` pinskia at gcc dot gnu.org
2021-11-11 9:59 ` pinskia at gcc dot gnu.org
` (4 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-11-11 9:56 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103183
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
There has to be C++ defect report about this. Because clang has the behavior
you are requesting but ICC, MSVC all act the same as GCC.
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c++/103183] ind[arr] produces an lvalue when arr is an array xvalue
2021-11-11 8:38 [Bug c++/103183] New: ind[arr] produces an lvalue when arr is an array xvalue de34 at live dot cn
2021-11-11 9:56 ` [Bug c++/103183] " pinskia at gcc dot gnu.org
@ 2021-11-11 9:59 ` pinskia at gcc dot gnu.org
2021-11-11 10:00 ` pinskia at gcc dot gnu.org
` (3 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-11-11 9:59 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103183
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Found it PR 79832.
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c++/103183] ind[arr] produces an lvalue when arr is an array xvalue
2021-11-11 8:38 [Bug c++/103183] New: ind[arr] produces an lvalue when arr is an array xvalue de34 at live dot cn
2021-11-11 9:56 ` [Bug c++/103183] " pinskia at gcc dot gnu.org
2021-11-11 9:59 ` pinskia at gcc dot gnu.org
@ 2021-11-11 10:00 ` pinskia at gcc dot gnu.org
2023-11-28 17:19 ` [Bug c++/103183] [11/12/13/14 Regression] " ppalka at gcc dot gnu.org
` (2 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-11-11 10:00 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103183
--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Andrew Pinski from comment #2)
> Found it PR 79832.
Well DR 1213, http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#1213
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c++/103183] [11/12/13/14 Regression] ind[arr] produces an lvalue when arr is an array xvalue
2021-11-11 8:38 [Bug c++/103183] New: ind[arr] produces an lvalue when arr is an array xvalue de34 at live dot cn
` (2 preceding siblings ...)
2021-11-11 10:00 ` pinskia at gcc dot gnu.org
@ 2023-11-28 17:19 ` ppalka at gcc dot gnu.org
2023-12-21 8:52 ` de34 at live dot cn
2024-03-10 3:21 ` law at gcc dot gnu.org
5 siblings, 0 replies; 7+ messages in thread
From: ppalka at gcc dot gnu.org @ 2023-11-28 17:19 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103183
Patrick Palka <ppalka at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |ppalka at gcc dot gnu.org
Summary|ind[arr] produces an lvalue |[11/12/13/14 Regression]
|when arr is an array xvalue |ind[arr] produces an lvalue
| |when arr is an array xvalue
Target Milestone|--- |11.5
--- Comment #4 from Patrick Palka <ppalka at gcc dot gnu.org> ---
Like PR103185, this one also started with r10-3793-g1a37b6d9a7e57c
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c++/103183] [11/12/13/14 Regression] ind[arr] produces an lvalue when arr is an array xvalue
2021-11-11 8:38 [Bug c++/103183] New: ind[arr] produces an lvalue when arr is an array xvalue de34 at live dot cn
` (3 preceding siblings ...)
2023-11-28 17:19 ` [Bug c++/103183] [11/12/13/14 Regression] " ppalka at gcc dot gnu.org
@ 2023-12-21 8:52 ` de34 at live dot cn
2024-03-10 3:21 ` law at gcc dot gnu.org
5 siblings, 0 replies; 7+ messages in thread
From: de34 at live dot cn @ 2023-12-21 8:52 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103183
--- Comment #5 from Jiang An <de34 at live dot cn> ---
Seems fixed together by commit
r14-6753-g8dfc52a75d4d6c8be1c61b4aa831b1812b14a10e.
https://godbolt.org/z/on3K451a5
^ permalink raw reply [flat|nested] 7+ messages in thread
* [Bug c++/103183] [11/12/13/14 Regression] ind[arr] produces an lvalue when arr is an array xvalue
2021-11-11 8:38 [Bug c++/103183] New: ind[arr] produces an lvalue when arr is an array xvalue de34 at live dot cn
` (4 preceding siblings ...)
2023-12-21 8:52 ` de34 at live dot cn
@ 2024-03-10 3:21 ` law at gcc dot gnu.org
5 siblings, 0 replies; 7+ messages in thread
From: law at gcc dot gnu.org @ 2024-03-10 3:21 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103183
Jeffrey A. Law <law at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
CC| |law at gcc dot gnu.org
Resolution|--- |FIXED
--- Comment #6 from Jeffrey A. Law <law at gcc dot gnu.org> ---
Per c#5.
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2024-03-10 3:21 UTC | newest]
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2021-11-11 8:38 [Bug c++/103183] New: ind[arr] produces an lvalue when arr is an array xvalue de34 at live dot cn
2021-11-11 9:56 ` [Bug c++/103183] " pinskia at gcc dot gnu.org
2021-11-11 9:59 ` pinskia at gcc dot gnu.org
2021-11-11 10:00 ` pinskia at gcc dot gnu.org
2023-11-28 17:19 ` [Bug c++/103183] [11/12/13/14 Regression] " ppalka at gcc dot gnu.org
2023-12-21 8:52 ` de34 at live dot cn
2024-03-10 3:21 ` law at gcc dot gnu.org
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