libcxx/test/std/utilities/variant/variant.helpers/variant_alternative.verify.cpp

   1 //===----------------------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 // UNSUPPORTED: c++03, c++11, c++14
  10
  11 // <variant>
  12
  13 // template <size_t I, class T> struct variant_alternative; // undefined
  14 // template <size_t I, class T> struct variant_alternative<I, const T>;
  15 // template <size_t I, class T> struct variant_alternative<I, volatile T>;
  16 // template <size_t I, class T> struct variant_alternative<I, const volatile T>;
  17 // template <size_t I, class T>
  18 //   using variant_alternative_t = typename variant_alternative<I, T>::type;
  19 //
  20 // template <size_t I, class... Types>
  21 //    struct variant_alternative<I, variant<Types...>>;
  22
  23 #include <memory>
  24 #include <type_traits>
  25 #include <variant>
  26
  27 int main(int, char**) {
  28     using V = std::variant<int, void *, const void *, long double>;
  29     std::variant_alternative<4, V>::type foo;  // expected-error@variant:* {{Index out of bounds in std::variant_alternative<>}}
  30
  31   return 0;
  32 }