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* [Bug libstdc++/105241] New: std::bitset::reference should have an ADL swap
@ 2022-04-12 16:39 arthur.j.odwyer at gmail dot com
2022-04-12 17:46 ` [Bug libstdc++/105241] " redi at gcc dot gnu.org
2022-04-12 18:27 ` redi at gcc dot gnu.org
0 siblings, 2 replies; 3+ messages in thread
From: arthur.j.odwyer at gmail dot com @ 2022-04-12 16:39 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105241
Bug ID: 105241
Summary: std::bitset::reference should have an ADL swap
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: arthur.j.odwyer at gmail dot com
Target Milestone: ---
(Originally reported by Nicholas Sielicki on the cpplang Slack)
// https://godbolt.org/z/138cPv5cn
#include <bitset>
#include <utility>
std::bitset<1> a = {1};
std::bitset<1> b = {0};
int main() {
using std::swap;
swap(a[0], b[0]);
return a[0] == 0 && b[0] == 1; // should be TRUE, right?
}
<source>:8:9: error: no matching function for call to
'swap(std::bitset<1>::reference, std::bitset<1>::reference)'
8 | swap(a[0], b[0]);
| ~~~~^~~~~~~~~~~~
Swapping elements via the std::swap two-step works for `std::vector<bool>`; I
see no reason it shouldn't also work for `std::bitset<N>`.
libc++ and Microsoft STL both support `swap` on `bitset::reference` just fine.
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug libstdc++/105241] std::bitset::reference should have an ADL swap
2022-04-12 16:39 [Bug libstdc++/105241] New: std::bitset::reference should have an ADL swap arthur.j.odwyer at gmail dot com
@ 2022-04-12 17:46 ` redi at gcc dot gnu.org
2022-04-12 18:27 ` redi at gcc dot gnu.org
1 sibling, 0 replies; 3+ messages in thread
From: redi at gcc dot gnu.org @ 2022-04-12 17:46 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105241
Jonathan Wakely <redi at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed| |2022-04-12
Ever confirmed|0 |1
--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to Arthur O'Dwyer from comment #0)
> Swapping elements via the std::swap two-step works for `std::vector<bool>`;
Not according to the C++ standard it doesn't. That's https://wg21.link/lwg3638
> I see no reason it shouldn't also work for `std::bitset<N>`.
I see no requirement in the standard for it to work.
> libc++ and Microsoft STL both support `swap` on `bitset::reference` just
> fine.
That's a non-standard extension.
I think we could add it to libstdc++, but this seems like an LWG issue to me.
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug libstdc++/105241] std::bitset::reference should have an ADL swap
2022-04-12 16:39 [Bug libstdc++/105241] New: std::bitset::reference should have an ADL swap arthur.j.odwyer at gmail dot com
2022-04-12 17:46 ` [Bug libstdc++/105241] " redi at gcc dot gnu.org
@ 2022-04-12 18:27 ` redi at gcc dot gnu.org
1 sibling, 0 replies; 3+ messages in thread
From: redi at gcc dot gnu.org @ 2022-04-12 18:27 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105241
Jonathan Wakely <redi at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Severity|normal |enhancement
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2022-04-12 18:27 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
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2022-04-12 16:39 [Bug libstdc++/105241] New: std::bitset::reference should have an ADL swap arthur.j.odwyer at gmail dot com
2022-04-12 17:46 ` [Bug libstdc++/105241] " redi at gcc dot gnu.org
2022-04-12 18:27 ` redi at gcc dot gnu.org
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