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// -*- C++ -*-
//===----------------------------------------------------------------------===//
//
// 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++98, c++03, c++11, c++14
// <variant>
// template <class... Types> struct hash<variant<Types...>>;
// template <> struct hash<monostate>;
#include <cassert>
#include <type_traits>
#include <variant>
#include "test_macros.h"
#include "variant_test_helpers.hpp"
#include "poisoned_hash_helper.hpp"
#ifndef TEST_HAS_NO_EXCEPTIONS
namespace std {
template <> struct hash<::MakeEmptyT> {
size_t operator()(const ::MakeEmptyT &) const {
assert(false);
return 0;
}
};
}
#endif
void test_hash_variant() {
{
using V = std::variant<int, long, int>;
using H = std::hash<V>;
const V v(std::in_place_index<0>, 42);
const V v_copy = v;
V v2(std::in_place_index<0>, 100);
const H h{};
assert(h(v) == h(v));
assert(h(v) != h(v2));
assert(h(v) == h(v_copy));
{
ASSERT_SAME_TYPE(decltype(h(v)), std::size_t);
static_assert(std::is_copy_constructible<H>::value, "");
}
}
{
using V = std::variant<std::monostate, int, long, const char *>;
using H = std::hash<V>;
const char *str = "hello";
const V v0;
const V v0_other;
const V v1(42);
const V v1_other(100);
V v2(100l);
V v2_other(999l);
V v3(str);
V v3_other("not hello");
const H h{};
assert(h(v0) == h(v0));
assert(h(v0) == h(v0_other));
assert(h(v1) == h(v1));
assert(h(v1) != h(v1_other));
assert(h(v2) == h(v2));
assert(h(v2) != h(v2_other));
assert(h(v3) == h(v3));
assert(h(v3) != h(v3_other));
assert(h(v0) != h(v1));
assert(h(v0) != h(v2));
assert(h(v0) != h(v3));
assert(h(v1) != h(v2));
assert(h(v1) != h(v3));
assert(h(v2) != h(v3));
}
#ifndef TEST_HAS_NO_EXCEPTIONS
{
using V = std::variant<int, MakeEmptyT>;
using H = std::hash<V>;
V v;
makeEmpty(v);
V v2;
makeEmpty(v2);
const H h{};
assert(h(v) == h(v2));
}
#endif
}
void test_hash_monostate() {
using H = std::hash<std::monostate>;
const H h{};
std::monostate m1{};
const std::monostate m2{};
assert(h(m1) == h(m1));
assert(h(m2) == h(m2));
assert(h(m1) == h(m2));
{
ASSERT_SAME_TYPE(decltype(h(m1)), std::size_t);
ASSERT_NOEXCEPT(h(m1));
static_assert(std::is_copy_constructible<H>::value, "");
}
{
test_hash_enabled_for_type<std::monostate>();
}
}
void test_hash_variant_duplicate_elements() {
// Test that the index of the alternative participates in the hash value.
using V = std::variant<std::monostate, std::monostate>;
using H = std::hash<V>;
H h{};
const V v1(std::in_place_index<0>);
const V v2(std::in_place_index<1>);
assert(h(v1) == h(v1));
assert(h(v2) == h(v2));
LIBCPP_ASSERT(h(v1) != h(v2));
}
struct A {};
struct B {};
namespace std {
template <>
struct hash<B> {
size_t operator()(B const&) const {
return 0;
}
};
}
void test_hash_variant_enabled() {
{
test_hash_enabled_for_type<std::variant<int> >();
test_hash_enabled_for_type<std::variant<int*, long, double, const int> >();
}
{
test_hash_disabled_for_type<std::variant<int, A>>();
test_hash_disabled_for_type<std::variant<const A, void*>>();
}
{
test_hash_enabled_for_type<std::variant<int, B>>();
test_hash_enabled_for_type<std::variant<const B, int>>();
}
}
int main() {
test_hash_variant();
test_hash_variant_duplicate_elements();
test_hash_monostate();
test_hash_variant_enabled();
}
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