test/libcxx/utilities/variant/variant.variant/variant.helper/variant_alternative.fail.cpp

//===----------------------------------------------------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

// <variant>
// UNSUPPORTED: c++98, c++03, c++11, c++14


// template <size_t I, class T> struct variant_alternative; // undefined
// template <size_t I, class T> struct variant_alternative<I, const T>;
// template <size_t I, class T> struct variant_alternative<I, volatile T>;
// template <size_t I, class T> struct variant_alternative<I, const volatile T>;
// template <size_t I, class T>
//   using variant_alternative_t = typename variant_alternative<I, T>::type;
//
// template <size_t I, class... Types>
//    struct variant_alternative<I, variant<Types...>>;


#include <variant>
#include <cassert>


int main()
{
    {
        typedef std::variant<int, double> T;
        std::variant_alternative<2, T>::type foo; // expected-note {{requested here}}
        // expected-error-re@variant:* {{static_assert failed{{( due to requirement '2UL < sizeof...\(_Types\)')?}} "Index out of bounds in std::variant_alternative<>"}}
    }
}