[Bug libstdc++/78442] New: [variant] std::get<...>(Variant) is not constexpr.

[eric at efcs dot ca]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78442

            Bug ID: 78442
           Summary: [variant] std::get<...>(Variant) is not constexpr.
           Product: gcc
           Version: 7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: eric at efcs dot ca
  Target Milestone: ---

See the below reproducer:

#include <variant>

constexpr bool test() {
  std::variant<int, void*> v(42);
  auto const& cv = v;
  static_assert(std::get<0>(v) == 42, "");
  static_assert(std::get<0>(cv) == 42, "");
  return true;
}
static_assert(test(), "");

int main() {}