https://gcc.gnu.org/bugzilla/show_bug.cgi?id=68429
--- Comment #1 from ryan.burn at gmail dot com ---
Additional case. (not sure if it's the same bug)
namespace std {
typedef int size_t;
template <typename _Tp, _Tp __v>
struct A {
static constexpr _Tp value = __v;
typedef _Tp value_type;
};
typedef A<bool, true> true_type;
template <bool, typename, typename>
struct conditional {
using type = int;
};
struct B : true_type {};
template <typename>
struct is_integral {
static constexpr bool value = true;
};
template <typename, typename>
struct is_same {
static constexpr bool value = true;
};
}
template <typename T, typename U>
concept bool Same = std::is_same<T, U>::value;
template <typename T>
concept bool Integral = requires{{T()}->Same<typename T::value_type>};
template <class...>
struct compose;
template <class T>
constexpr typename T::value_type _v = T::value;
template <long N>
using size_t = std::A<long, N>;
template <bool B>
using bool_ = std::A<bool, B>;
template <class Fn, typename... Args>
using apply = typename Fn::template apply<Args...>;
namespace detail {
template <template <typename...> class C, typename... Ts>
struct defer_ {
using type = C<Ts...>;
};
}
template <template <typename...> class C, typename... Ts>
struct defer : detail::defer_<C, Ts...> {};
template <class Fn0>
struct compose<Fn0> {
template <typename... Ts>
using apply = apply<Fn0, Ts...>;
};
template <class Fn0, class... Fns>
struct compose<Fn0, Fns...> {
template <typename... Ts>
using apply = apply<Fn0, apply<compose<Fns...>, Ts...>>;
};
template <template <typename...> class C>
struct quote {
template <typename... Ts>
using apply = typename defer<C, Ts...>::type;
};
namespace detail {
template <typename...>
struct _if_;
template <Integral If, typename Then, typename Else>
struct _if_<If, Then, Else> : std::conditional<_v<If>, Then, Else> {};
}
template <typename... Args>
using if_ = typename detail::_if_<Args...>::type;
template <bool B>
using not_c = bool_<!B>;
template <Integral B>
using not_ = not_c<_v<B>>;
template <typename... Ts>
struct list {
};
namespace detail {
template <typename, typename>
struct find_if_ {
};
template <typename Head, typename... L, typename Fn>
struct find_if_<list<Head, L...>, Fn>
: if_<apply<Fn, Head>, list<>, find_if_<int, Fn>> {};
}
template <class L, class Fn>
using find_if = typename detail::find_if_<L, Fn>::type;
template <class Fn>
using not_fn = compose<quote<not_>, Fn>;
template <class L, class Fn>
using all_of = find_if<L, not_fn<Fn>>;
static_assert(all_of<list<long>, quote<std::is_integral>>::value);
