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.
