https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101945
Patrick Palka <ppalka at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |ppalka at gcc dot gnu.org
Resolution|--- |DUPLICATE
Status|UNCONFIRMED |RESOLVED
--- Comment #2 from Patrick Palka <ppalka at gcc dot gnu.org> ---
I think GCC is correct to diagnose the constraint recursion, for similar
reasons as for the testcases in PR100288 / PR99599. In order to make your
example work, you need to add extra constraints to your overloads. Something
like:
#include <concepts>
template <class T> struct wrapper
{
using type = T;
T value;
};
template<class T>
constexpr bool is_wrapper_v = false;
template<class T>
constexpr bool is_wrapper_v<wrapper<T>> = true;
template<class T>
concept is_wrapper = is_wrapper_v<T>;
template <is_wrapper WT, is_wrapper WU, class T = WT::type, class U = WU::type>
requires std::equality_comparable_with <T, U>
constexpr bool operator == (WT const& a, WU const& b)
{
return a.value == b.value;
}
template <is_wrapper WT, class U, class T = WT::type>
requires (!is_wrapper<U>) && std::equality_comparable_with <T, U>
constexpr bool operator == (WT const& a, U const& b)
{
return a.value == b;
}
template <class T, is_wrapper WU, class U = WU::type>
requires (!is_wrapper<T>) && std::equality_comparable_with <T, U>
constexpr bool operator == (T const& a, WU const& b)
{
return a == b.value;
}
constexpr auto a = wrapper <int> { 2 };
constexpr auto b = a;
static_assert (a == b);
int main () {}
*** This bug has been marked as a duplicate of bug 100288 ***
