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78 lines
2.5 KiB
C++
78 lines
2.5 KiB
C++
// -*- C++ -*-
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//===----------------------------------------------------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is dual licensed under the MIT and the University of Illinois Open
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// Source Licenses. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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// UNSUPPORTED: c++98, c++03, c++11, c++14
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// <variant>
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// template <size_t I, class T> struct variant_alternative; // undefined
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// template <size_t I, class T> struct variant_alternative<I, const T>;
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// template <size_t I, class T> struct variant_alternative<I, volatile T>;
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// template <size_t I, class T> struct variant_alternative<I, const volatile T>;
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// template <size_t I, class T>
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// using variant_alternative_t = typename variant_alternative<I, T>::type;
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//
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// template <size_t I, class... Types>
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// struct variant_alternative<I, variant<Types...>>;
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#include <memory>
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#include <type_traits>
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#include <variant>
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#include "test_macros.h"
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#include "variant_test_helpers.hpp"
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template <class V, size_t I, class E> void test() {
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static_assert(
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std::is_same_v<typename std::variant_alternative<I, V>::type, E>, "");
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static_assert(
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std::is_same_v<typename std::variant_alternative<I, const V>::type,
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const E>,
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"");
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static_assert(
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std::is_same_v<typename std::variant_alternative<I, volatile V>::type,
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volatile E>,
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"");
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static_assert(
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std::is_same_v<
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typename std::variant_alternative<I, const volatile V>::type,
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const volatile E>,
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"");
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static_assert(std::is_same_v<std::variant_alternative_t<I, V>, E>, "");
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static_assert(std::is_same_v<std::variant_alternative_t<I, const V>, const E>,
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"");
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static_assert(
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std::is_same_v<std::variant_alternative_t<I, volatile V>, volatile E>,
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"");
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static_assert(std::is_same_v<std::variant_alternative_t<I, const volatile V>,
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const volatile E>,
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"");
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}
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int main() {
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{
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using V = std::variant<int, void *, const void *, long double>;
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test<V, 0, int>();
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test<V, 1, void *>();
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test<V, 2, const void *>();
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test<V, 3, long double>();
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}
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#if !defined(TEST_VARIANT_HAS_NO_REFERENCES)
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{
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using V = std::variant<int, int &, const int &, int &&, long double>;
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test<V, 0, int>();
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test<V, 1, int &>();
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test<V, 2, const int &>();
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test<V, 3, int &&>();
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test<V, 4, long double>();
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}
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#endif
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}
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