https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89851
Bug ID: 89851
Summary: [Regression] std::variant comparison operators violate
[variant.relops]
Product: gcc
Version: 9.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: antoshkka at gmail dot com
Target Milestone: ---
The following function should return `false` according to [variant.relops]:
#include <variant>
using V = std::variant<int, int>;
bool test1() {
V v1{std::in_place_index<0>, 0};
V v2{std::in_place_index<1>, 0};
return v1 == v2;
}
std::variant in GCC-8 was returning `false`, however the variant from GCC-9
returns `true`.
This could be quickly fixed by comparing indexes at the start of each operator.
Another way of fixing is to pass integral_constants instead of types into the
__do_visit function.
