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llvm / llvm-project / libcxx / e8e5fb57f80252d4a88e5fc1485f1fa03d87adf1 / . / test / std / language.support / cmp / cmp.alg / weak_order.pass.cpp
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//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
// UNSUPPORTED: c++03, c++11, c++14, c++17
// UNSUPPORTED: libcpp-no-concepts
// <compare>
// template<class T> constexpr weak_ordering weak_order(const T& a, const T& b);
#include <compare>
#include <cassert>
#include <cmath>
#include <iterator> // std::size
#include <limits>
#include <type_traits>
#include <utility>
#include "test_macros.h"
template<class T, class U>
constexpr auto has_weak_order(T&& t, U&& u)
-> decltype(std::weak_order(static_cast<T&&>(t), static_cast<U&&>(u)), true)
{
return true;
}
constexpr bool has_weak_order(...) {
return false;
}
namespace N11 {
struct A {};
struct B {};
std::strong_ordering weak_order(const A&, const A&) { return std::strong_ordering::less; }
std::strong_ordering weak_order(const A&, const B&);
}
void test_1_1()
{
// If the decayed types of E and F differ, weak_order(E, F) is ill-formed.
static_assert( has_weak_order(1, 2));
static_assert(!has_weak_order(1, (short)2));
static_assert(!has_weak_order(1, 2.0));
static_assert(!has_weak_order(1.0f, 2.0));
static_assert( has_weak_order((int*)nullptr, (int*)nullptr));
static_assert(!has_weak_order((int*)nullptr, (const int*)nullptr));
static_assert(!has_weak_order((const int*)nullptr, (int*)nullptr));
static_assert( has_weak_order((const int*)nullptr, (const int*)nullptr));
N11::A a;
N11::B b;
static_assert( has_weak_order(a, a));
static_assert(!has_weak_order(a, b));
}
namespace N12 {
struct A {};
std::strong_ordering weak_order(A&, A&&) { return std::strong_ordering::less; }
std::strong_ordering weak_order(A&&, A&&) { return std::strong_ordering::equal; }
std::strong_ordering weak_order(const A&, const A&);
struct B {
friend std::partial_ordering weak_order(B&, B&);
};
struct WeakOrder {
explicit operator std::weak_ordering() const { return std::weak_ordering::less; }
};
struct C {
bool touched = false;
friend WeakOrder weak_order(C& lhs, C&) { lhs.touched = true; return WeakOrder(); }
};
}
void test_1_2()
{
// Otherwise, weak_ordering(weak_order(E, F))
// if it is a well-formed expression with overload resolution performed
// in a context that does not include a declaration of std::weak_order.
// Test that weak_order does not const-qualify the forwarded arguments.
N12::A a;
assert(std::weak_order(a, std::move(a)) == std::weak_ordering::less);
assert(std::weak_order(std::move(a), std::move(a)) == std::weak_ordering::equivalent);
// The type of weak_order(e,f) must be explicitly convertible to weak_ordering.
N12::B b;
static_assert(!has_weak_order(b, b));
N12::C c1, c2;
ASSERT_SAME_TYPE(decltype(std::weak_order(c1, c2)), std::weak_ordering);
assert(std::weak_order(c1, c2) == std::weak_ordering::less);
assert(c1.touched);
assert(!c2.touched);
}
template<class F>
constexpr bool test_1_3()
{
// Otherwise, if the decayed type T of E is a floating-point type,
// yields a value of type weak_ordering that is consistent with
// the ordering observed by T's comparison operators and strong_order,
// and if numeric_limits<T>::is_iec559 is true, is additionally consistent with
// the following equivalence classes...
// std::numeric_limits<F>::is_iec559 is usually true.
// It is false for F=long double on AIX; but this test is still expected
// to pass (e.g. std::weak_order(+0, -0) == weak_ordering::equivalent,
// even on AIX).
ASSERT_SAME_TYPE(decltype(std::weak_order(F(0), F(0))), std::weak_ordering);
F v[] = {
-std::numeric_limits<F>::infinity(),
std::numeric_limits<F>::lowest(), // largest (finite) negative number
F(-1.0), F(-0.1),
-std::numeric_limits<F>::min(), // smallest (normal) negative number
F(-0.0), // negative zero
F(0.0),
std::numeric_limits<F>::min(), // smallest (normal) positive number
F(0.1), F(1.0), F(2.0), F(3.14),
std::numeric_limits<F>::max(), // largest (finite) positive number
std::numeric_limits<F>::infinity(),
};
static_assert(std::size(v) == 14);
// Sanity-check that array 'v' is indeed in the right order.
for (int i=0; i < 14; ++i) {
for (int j=0; j < 14; ++j) {
auto naturalOrder = (v[i] <=> v[j]);
if (v[i] == 0 && v[j] == 0) {
assert(naturalOrder == std::partial_ordering::equivalent);
} else {
assert(naturalOrder == std::partial_ordering::unordered || naturalOrder == (i <=> j));
}
}
}
assert(std::weak_order(v[0], v[0]) == std::weak_ordering::equivalent);
assert(std::weak_order(v[0], v[1]) == std::weak_ordering::less);
assert(std::weak_order(v[0], v[2]) == std::weak_ordering::less);
assert(std::weak_order(v[0], v[3]) == std::weak_ordering::less);
assert(std::weak_order(v[0], v[4]) == std::weak_ordering::less);
assert(std::weak_order(v[0], v[5]) == std::weak_ordering::less);
assert(std::weak_order(v[0], v[6]) == std::weak_ordering::less);
assert(std::weak_order(v[0], v[7]) == std::weak_ordering::less);
assert(std::weak_order(v[0], v[8]) == std::weak_ordering::less);
assert(std::weak_order(v[0], v[9]) == std::weak_ordering::less);
assert(std::weak_order(v[0], v[10]) == std::weak_ordering::less);
assert(std::weak_order(v[0], v[11]) == std::weak_ordering::less);
assert(std::weak_order(v[0], v[12]) == std::weak_ordering::less);
assert(std::weak_order(v[0], v[13]) == std::weak_ordering::less);
assert(std::weak_order(v[1], v[0]) == std::weak_ordering::greater);
assert(std::weak_order(v[1], v[1]) == std::weak_ordering::equivalent);
assert(std::weak_order(v[1], v[2]) == std::weak_ordering::less);
assert(std::weak_order(v[1], v[3]) == std::weak_ordering::less);
assert(std::weak_order(v[1], v[4]) == std::weak_ordering::less);
assert(std::weak_order(v[1], v[5]) == std::weak_ordering::less);
assert(std::weak_order(v[1], v[6]) == std::weak_ordering::less);
assert(std::weak_order(v[1], v[7]) == std::weak_ordering::less);
assert(std::weak_order(v[1], v[8]) == std::weak_ordering::less);
assert(std::weak_order(v[1], v[9]) == std::weak_ordering::less);
assert(std::weak_order(v[1], v[10]) == std::weak_ordering::less);
assert(std::weak_order(v[1], v[11]) == std::weak_ordering::less);
assert(std::weak_order(v[1], v[12]) == std::weak_ordering::less);
assert(std::weak_order(v[1], v[13]) == std::weak_ordering::less);
assert(std::weak_order(v[2], v[0]) == std::weak_ordering::greater);
assert(std::weak_order(v[2], v[1]) == std::weak_ordering::greater);
assert(std::weak_order(v[2], v[2]) == std::weak_ordering::equivalent);
assert(std::weak_order(v[2], v[3]) == std::weak_ordering::less);
assert(std::weak_order(v[2], v[4]) == std::weak_ordering::less);
assert(std::weak_order(v[2], v[5]) == std::weak_ordering::less);
assert(std::weak_order(v[2], v[6]) == std::weak_ordering::less);
assert(std::weak_order(v[2], v[7]) == std::weak_ordering::less);
assert(std::weak_order(v[2], v[8]) == std::weak_ordering::less);
assert(std::weak_order(v[2], v[9]) == std::weak_ordering::less);
assert(std::weak_order(v[2], v[10]) == std::weak_ordering::less);
assert(std::weak_order(v[2], v[11]) == std::weak_ordering::less);
assert(std::weak_order(v[2], v[12]) == std::weak_ordering::less);
assert(std::weak_order(v[2], v[13]) == std::weak_ordering::less);
assert(std::weak_order(v[3], v[0]) == std::weak_ordering::greater);
assert(std::weak_order(v[3], v[1]) == std::weak_ordering::greater);
assert(std::weak_order(v[3], v[2]) == std::weak_ordering::greater);
assert(std::weak_order(v[3], v[3]) == std::weak_ordering::equivalent);
assert(std::weak_order(v[3], v[4]) == std::weak_ordering::less);
assert(std::weak_order(v[3], v[5]) == std::weak_ordering::less);
assert(std::weak_order(v[3], v[6]) == std::weak_ordering::less);
assert(std::weak_order(v[3], v[7]) == std::weak_ordering::less);
assert(std::weak_order(v[3], v[8]) == std::weak_ordering::less);
assert(std::weak_order(v[3], v[9]) == std::weak_ordering::less);
assert(std::weak_order(v[3], v[10]) == std::weak_ordering::less);
assert(std::weak_order(v[3], v[11]) == std::weak_ordering::less);
assert(std::weak_order(v[3], v[12]) == std::weak_ordering::less);
assert(std::weak_order(v[3], v[13]) == std::weak_ordering::less);
assert(std::weak_order(v[4], v[0]) == std::weak_ordering::greater);
assert(std::weak_order(v[4], v[1]) == std::weak_ordering::greater);
assert(std::weak_order(v[4], v[2]) == std::weak_ordering::greater);
assert(std::weak_order(v[4], v[3]) == std::weak_ordering::greater);
assert(std::weak_order(v[4], v[4]) == std::weak_ordering::equivalent);
assert(std::weak_order(v[4], v[5]) == std::weak_ordering::less);
assert(std::weak_order(v[4], v[6]) == std::weak_ordering::less);
assert(std::weak_order(v[4], v[7]) == std::weak_ordering::less);
assert(std::weak_order(v[4], v[8]) == std::weak_ordering::less);
assert(std::weak_order(v[4], v[9]) == std::weak_ordering::less);
assert(std::weak_order(v[4], v[10]) == std::weak_ordering::less);
assert(std::weak_order(v[4], v[11]) == std::weak_ordering::less);
assert(std::weak_order(v[4], v[12]) == std::weak_ordering::less);
assert(std::weak_order(v[4], v[13]) == std::weak_ordering::less);
assert(std::weak_order(v[5], v[0]) == std::weak_ordering::greater);
assert(std::weak_order(v[5], v[1]) == std::weak_ordering::greater);
assert(std::weak_order(v[5], v[2]) == std::weak_ordering::greater);
assert(std::weak_order(v[5], v[3]) == std::weak_ordering::greater);
assert(std::weak_order(v[5], v[4]) == std::weak_ordering::greater);
assert(std::weak_order(v[5], v[5]) == std::weak_ordering::equivalent);
assert(std::weak_order(v[5], v[6]) == std::weak_ordering::equivalent);
assert(std::weak_order(v[5], v[7]) == std::weak_ordering::less);
assert(std::weak_order(v[5], v[8]) == std::weak_ordering::less);
assert(std::weak_order(v[5], v[9]) == std::weak_ordering::less);
assert(std::weak_order(v[5], v[10]) == std::weak_ordering::less);
assert(std::weak_order(v[5], v[11]) == std::weak_ordering::less);
assert(std::weak_order(v[5], v[12]) == std::weak_ordering::less);
assert(std::weak_order(v[5], v[13]) == std::weak_ordering::less);
assert(std::weak_order(v[6], v[0]) == std::weak_ordering::greater);
assert(std::weak_order(v[6], v[1]) == std::weak_ordering::greater);
assert(std::weak_order(v[6], v[2]) == std::weak_ordering::greater);
assert(std::weak_order(v[6], v[3]) == std::weak_ordering::greater);
assert(std::weak_order(v[6], v[4]) == std::weak_ordering::greater);
assert(std::weak_order(v[6], v[5]) == std::weak_ordering::equivalent);
assert(std::weak_order(v[6], v[6]) == std::weak_ordering::equivalent);
assert(std::weak_order(v[6], v[7]) == std::weak_ordering::less);
assert(std::weak_order(v[6], v[8]) == std::weak_ordering::less);
assert(std::weak_order(v[6], v[9]) == std::weak_ordering::less);
assert(std::weak_order(v[6], v[10]) == std::weak_ordering::less);
assert(std::weak_order(v[6], v[11]) == std::weak_ordering::less);
assert(std::weak_order(v[6], v[12]) == std::weak_ordering::less);
assert(std::weak_order(v[6], v[13]) == std::weak_ordering::less);
assert(std::weak_order(v[7], v[0]) == std::weak_ordering::greater);
assert(std::weak_order(v[7], v[1]) == std::weak_ordering::greater);
assert(std::weak_order(v[7], v[2]) == std::weak_ordering::greater);
assert(std::weak_order(v[7], v[3]) == std::weak_ordering::greater);
assert(std::weak_order(v[7], v[4]) == std::weak_ordering::greater);
assert(std::weak_order(v[7], v[5]) == std::weak_ordering::greater);
assert(std::weak_order(v[7], v[6]) == std::weak_ordering::greater);
assert(std::weak_order(v[7], v[7]) == std::weak_ordering::equivalent);
assert(std::weak_order(v[7], v[8]) == std::weak_ordering::less);
assert(std::weak_order(v[7], v[9]) == std::weak_ordering::less);
assert(std::weak_order(v[7], v[10]) == std::weak_ordering::less);
assert(std::weak_order(v[7], v[11]) == std::weak_ordering::less);
assert(std::weak_order(v[7], v[12]) == std::weak_ordering::less);
assert(std::weak_order(v[7], v[13]) == std::weak_ordering::less);
assert(std::weak_order(v[8], v[0]) == std::weak_ordering::greater);
assert(std::weak_order(v[8], v[1]) == std::weak_ordering::greater);
assert(std::weak_order(v[8], v[2]) == std::weak_ordering::greater);
assert(std::weak_order(v[8], v[3]) == std::weak_ordering::greater);
assert(std::weak_order(v[8], v[4]) == std::weak_ordering::greater);
assert(std::weak_order(v[8], v[5]) == std::weak_ordering::greater);
assert(std::weak_order(v[8], v[6]) == std::weak_ordering::greater);
assert(std::weak_order(v[8], v[7]) == std::weak_ordering::greater);
assert(std::weak_order(v[8], v[8]) == std::weak_ordering::equivalent);
assert(std::weak_order(v[8], v[9]) == std::weak_ordering::less);
assert(std::weak_order(v[8], v[10]) == std::weak_ordering::less);
assert(std::weak_order(v[8], v[11]) == std::weak_ordering::less);
assert(std::weak_order(v[8], v[12]) == std::weak_ordering::less);
assert(std::weak_order(v[8], v[13]) == std::weak_ordering::less);
assert(std::weak_order(v[9], v[0]) == std::weak_ordering::greater);
assert(std::weak_order(v[9], v[1]) == std::weak_ordering::greater);
assert(std::weak_order(v[9], v[2]) == std::weak_ordering::greater);
assert(std::weak_order(v[9], v[3]) == std::weak_ordering::greater);
assert(std::weak_order(v[9], v[4]) == std::weak_ordering::greater);
assert(std::weak_order(v[9], v[5]) == std::weak_ordering::greater);
assert(std::weak_order(v[9], v[6]) == std::weak_ordering::greater);
assert(std::weak_order(v[9], v[7]) == std::weak_ordering::greater);
assert(std::weak_order(v[9], v[8]) == std::weak_ordering::greater);
assert(std::weak_order(v[9], v[9]) == std::weak_ordering::equivalent);
assert(std::weak_order(v[9], v[10]) == std::weak_ordering::less);
assert(std::weak_order(v[9], v[11]) == std::weak_ordering::less);
assert(std::weak_order(v[9], v[12]) == std::weak_ordering::less);
assert(std::weak_order(v[9], v[13]) == std::weak_ordering::less);
assert(std::weak_order(v[10], v[0]) == std::weak_ordering::greater);
assert(std::weak_order(v[10], v[1]) == std::weak_ordering::greater);
assert(std::weak_order(v[10], v[2]) == std::weak_ordering::greater);
assert(std::weak_order(v[10], v[3]) == std::weak_ordering::greater);
assert(std::weak_order(v[10], v[4]) == std::weak_ordering::greater);
assert(std::weak_order(v[10], v[5]) == std::weak_ordering::greater);
assert(std::weak_order(v[10], v[6]) == std::weak_ordering::greater);
assert(std::weak_order(v[10], v[7]) == std::weak_ordering::greater);
assert(std::weak_order(v[10], v[8]) == std::weak_ordering::greater);
assert(std::weak_order(v[10], v[9]) == std::weak_ordering::greater);
assert(std::weak_order(v[10], v[10]) == std::weak_ordering::equivalent);
assert(std::weak_order(v[10], v[11]) == std::weak_ordering::less);
assert(std::weak_order(v[10], v[12]) == std::weak_ordering::less);
assert(std::weak_order(v[10], v[13]) == std::weak_ordering::less);
assert(std::weak_order(v[11], v[0]) == std::weak_ordering::greater);
assert(std::weak_order(v[11], v[1]) == std::weak_ordering::greater);
assert(std::weak_order(v[11], v[2]) == std::weak_ordering::greater);
assert(std::weak_order(v[11], v[3]) == std::weak_ordering::greater);
assert(std::weak_order(v[11], v[4]) == std::weak_ordering::greater);
assert(std::weak_order(v[11], v[5]) == std::weak_ordering::greater);
assert(std::weak_order(v[11], v[6]) == std::weak_ordering::greater);
assert(std::weak_order(v[11], v[7]) == std::weak_ordering::greater);
assert(std::weak_order(v[11], v[8]) == std::weak_ordering::greater);
assert(std::weak_order(v[11], v[9]) == std::weak_ordering::greater);
assert(std::weak_order(v[11], v[10]) == std::weak_ordering::greater);
assert(std::weak_order(v[11], v[11]) == std::weak_ordering::equivalent);
assert(std::weak_order(v[11], v[12]) == std::weak_ordering::less);
assert(std::weak_order(v[11], v[13]) == std::weak_ordering::less);
assert(std::weak_order(v[12], v[0]) == std::weak_ordering::greater);
assert(std::weak_order(v[12], v[1]) == std::weak_ordering::greater);
assert(std::weak_order(v[12], v[2]) == std::weak_ordering::greater);
assert(std::weak_order(v[12], v[3]) == std::weak_ordering::greater);
assert(std::weak_order(v[12], v[4]) == std::weak_ordering::greater);
assert(std::weak_order(v[12], v[5]) == std::weak_ordering::greater);
assert(std::weak_order(v[12], v[6]) == std::weak_ordering::greater);
assert(std::weak_order(v[12], v[7]) == std::weak_ordering::greater);
assert(std::weak_order(v[12], v[8]) == std::weak_ordering::greater);
assert(std::weak_order(v[12], v[9]) == std::weak_ordering::greater);
assert(std::weak_order(v[12], v[10]) == std::weak_ordering::greater);
assert(std::weak_order(v[12], v[11]) == std::weak_ordering::greater);
assert(std::weak_order(v[12], v[12]) == std::weak_ordering::equivalent);
assert(std::weak_order(v[12], v[13]) == std::weak_ordering::less);
assert(std::weak_order(v[13], v[0]) == std::weak_ordering::greater);
assert(std::weak_order(v[13], v[1]) == std::weak_ordering::greater);
assert(std::weak_order(v[13], v[2]) == std::weak_ordering::greater);
assert(std::weak_order(v[13], v[3]) == std::weak_ordering::greater);
assert(std::weak_order(v[13], v[4]) == std::weak_ordering::greater);
assert(std::weak_order(v[13], v[5]) == std::weak_ordering::greater);
assert(std::weak_order(v[13], v[6]) == std::weak_ordering::greater);
assert(std::weak_order(v[13], v[7]) == std::weak_ordering::greater);
assert(std::weak_order(v[13], v[8]) == std::weak_ordering::greater);
assert(std::weak_order(v[13], v[9]) == std::weak_ordering::greater);
assert(std::weak_order(v[13], v[10]) == std::weak_ordering::greater);
assert(std::weak_order(v[13], v[11]) == std::weak_ordering::greater);
assert(std::weak_order(v[13], v[12]) == std::weak_ordering::greater);
assert(std::weak_order(v[13], v[13]) == std::weak_ordering::equivalent);
// There's no way to produce a specifically positive or negative NAN
// at compile-time, so the NAN-related tests must be runtime-only.
if (!std::is_constant_evaluated()) {
F nq = _VSTD::copysign(std::numeric_limits<F>::quiet_NaN(), F(-1));
F ns = _VSTD::copysign(std::numeric_limits<F>::signaling_NaN(), F(-1));
F ps = _VSTD::copysign(std::numeric_limits<F>::signaling_NaN(), F(+1));
F pq = _VSTD::copysign(std::numeric_limits<F>::quiet_NaN(), F(+1));
assert(std::weak_order(nq, nq) == std::weak_ordering::equivalent);
assert(std::weak_order(nq, ns) == std::weak_ordering::equivalent);
for (int i=0; i < 14; ++i) {
assert(std::weak_order(nq, v[i]) == std::weak_ordering::less);
}
assert(std::weak_order(nq, ps) == std::weak_ordering::less);
assert(std::weak_order(nq, pq) == std::weak_ordering::less);
assert(std::weak_order(ns, nq) == std::weak_ordering::equivalent);
assert(std::weak_order(ns, ns) == std::weak_ordering::equivalent);
for (int i=0; i < 14; ++i) {
assert(std::weak_order(ns, v[i]) == std::weak_ordering::less);
}
assert(std::weak_order(ns, ps) == std::weak_ordering::less);
assert(std::weak_order(ns, pq) == std::weak_ordering::less);
assert(std::weak_order(ps, nq) == std::weak_ordering::greater);
assert(std::weak_order(ps, ns) == std::weak_ordering::greater);
for (int i=0; i < 14; ++i) {
assert(std::weak_order(ps, v[i]) == std::weak_ordering::greater);
}
assert(std::weak_order(ps, ps) == std::weak_ordering::equivalent);
assert(std::weak_order(ps, pq) == std::weak_ordering::equivalent);
assert(std::weak_order(pq, nq) == std::weak_ordering::greater);
assert(std::weak_order(pq, ns) == std::weak_ordering::greater);
for (int i=0; i < 14; ++i) {
assert(std::weak_order(pq, v[i]) == std::weak_ordering::greater);
}
assert(std::weak_order(pq, ps) == std::weak_ordering::equivalent);
assert(std::weak_order(pq, pq) == std::weak_ordering::equivalent);
}
return true;
}
namespace N14 {
// Compare to N12::A.
struct A {};
bool operator==(const A&, const A&);
constexpr std::weak_ordering operator<=>(A&, A&&) { return std::weak_ordering::less; }
constexpr std::weak_ordering operator<=>(A&&, A&&) { return std::weak_ordering::equivalent; }
std::weak_ordering operator<=>(const A&, const A&);
static_assert(std::three_way_comparable<A>);
struct B {
std::weak_ordering operator<=>(const B&) const; // lacks operator==
};
static_assert(!std::three_way_comparable<B>);
struct C {
bool *touched;
bool operator==(const C&) const;
constexpr std::weak_ordering operator<=>(const C& rhs) const {
*rhs.touched = true;
return std::weak_ordering::equivalent;
}
};
static_assert(std::three_way_comparable<C>);
}
constexpr bool test_1_4()
{
// Otherwise, weak_ordering(compare_three_way()(E, F)) if it is a well-formed expression.
// Test neither weak_order nor compare_three_way const-qualify the forwarded arguments.
N14::A a;
assert(std::weak_order(a, std::move(a)) == std::weak_ordering::less);
assert(std::weak_order(std::move(a), std::move(a)) == std::weak_ordering::equivalent);
N14::B b;
static_assert(!has_weak_order(b, b));
// Test that the arguments are passed to <=> in the correct order.
bool c1_touched = false;
bool c2_touched = false;
N14::C c1 = {&c1_touched};
N14::C c2 = {&c2_touched};
assert(std::weak_order(c1, c2) == std::weak_ordering::equivalent);
assert(!c1_touched);
assert(c2_touched);
return true;
}
namespace N15 {
struct A {};
constexpr std::strong_ordering strong_order(A&, A&&) { return std::strong_ordering::less; }
constexpr std::strong_ordering strong_order(A&&, A&&) { return std::strong_ordering::equal; }
std::strong_ordering strong_order(const A&, const A&);
struct B {
friend std::weak_ordering strong_order(B&, B&);
};
struct WeakOrder {
operator std::weak_ordering() const { return std::weak_ordering::less; }
};
struct C {
friend WeakOrder strong_order(C& lhs, C&);
};
struct StrongOrder {
constexpr explicit operator std::strong_ordering() const { return std::strong_ordering::less; }
operator std::weak_ordering() const = delete;
};
struct D {
bool touched = false;
friend constexpr StrongOrder strong_order(D& lhs, D&) { lhs.touched = true; return StrongOrder(); }
};
}
constexpr bool test_1_5()
{
// Otherwise, weak_ordering(strong_order(E, F)) [that is, std::strong_order]
// if it is a well-formed expression.
// Test that weak_order and strong_order do not const-qualify the forwarded arguments.
N15::A a;
assert(std::weak_order(a, std::move(a)) == std::weak_ordering::less);
assert(std::weak_order(std::move(a), std::move(a)) == std::weak_ordering::equivalent);
// The type of ADL strong_order(e,f) must be explicitly convertible to strong_ordering
// (not just to weak_ordering), or else std::strong_order(e,f) won't exist.
N15::B b;
static_assert(!has_weak_order(b, b));
// The type of ADL strong_order(e,f) must be explicitly convertible to strong_ordering
// (not just to weak_ordering), or else std::strong_order(e,f) won't exist.
N15::C c;
static_assert(!has_weak_order(c, c));
N15::D d1, d2;
ASSERT_SAME_TYPE(decltype(std::weak_order(d1, d2)), std::weak_ordering);
assert(std::weak_order(d1, d2) == std::weak_ordering::less);
assert(d1.touched);
assert(!d2.touched);
return true;
}
int main(int, char**)
{
test_1_1();
test_1_2();
test_1_3<float>();
test_1_3<double>();
test_1_3<long double>();
test_1_4();
test_1_5();
static_assert(test_1_3<float>());
static_assert(test_1_3<double>());
static_assert(test_1_3<long double>());
static_assert(test_1_4());
static_assert(test_1_5());
return 0;
}