text: //===----------------------------------------------------------------------===//
  //
  //                     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.
  //
  //===----------------------------------------------------------------------===//
  
  // <tuple>
  
  // template <class... Types> class tuple;
  
  // constexpr tuple();
  
  // UNSUPPORTED: c++98, c++03
  
  #include <tuple>
  #include <string>
  #include <cassert>
  #include <type_traits>
  
  #include "DefaultOnly.h"
  
  struct NoDefault {
      NoDefault() = delete;
      explicit NoDefault(int) { }
  };
  
  struct NoExceptDefault {
      NoExceptDefault() noexcept = default;
  };
  
  struct ThrowingDefault {
      ThrowingDefault() { }
  };
  
  struct IllFormedDefault {
      IllFormedDefault(int x) : value(x) {}
      template <bool Pred = false>
      constexpr IllFormedDefault() {
          static_assert(Pred,
              "The default constructor should not be instantiated");
      }
      int value;
  };
  
  int main()
  {
      {
          std::tuple<> t;
      }
      {
          std::tuple<int> t;
          assert(std::get<0>(t) == 0);
      }
      {
          std::tuple<int, char*> t;
          assert(std::get<0>(t) == 0);
          assert(std::get<1>(t) == nullptr);
      }
      {
          std::tuple<int, char*, std::string> t;
          assert(std::get<0>(t) == 0);
          assert(std::get<1>(t) == nullptr);
          assert(std::get<2>(t) == "");
      }
      {
          std::tuple<int, char*, std::string, DefaultOnly> t;
          assert(std::get<0>(t) == 0);
          assert(std::get<1>(t) == nullptr);
          assert(std::get<2>(t) == "");
          assert(std::get<3>(t) == DefaultOnly());
      }
      {
          // See bug #21157.
          static_assert(!std::is_default_constructible<std::tuple<NoDefault>>(), "");
          static_assert(!std::is_default_constructible<std::tuple<DefaultOnly, NoDefault>>(), "");
          static_assert(!std::is_default_constructible<std::tuple<NoDefault, DefaultOnly, NoDefault>>(), "");
      }
      {
          static_assert(noexcept(std::tuple<NoExceptDefault>()), "");
          static_assert(noexcept(std::tuple<NoExceptDefault, NoExceptDefault>()), "");
  
          static_assert(!noexcept(std::tuple<ThrowingDefault, NoExceptDefault>()), "");
          static_assert(!noexcept(std::tuple<NoExceptDefault, ThrowingDefault>()), "");
          static_assert(!noexcept(std::tuple<ThrowingDefault, ThrowingDefault>()), "");
      }
  #ifndef _LIBCPP_HAS_NO_CONSTEXPR
      {
          constexpr std::tuple<> t;
      }
      {
          constexpr std::tuple<int> t;
          assert(std::get<0>(t) == 0);
      }
      {
          constexpr std::tuple<int, char*> t;
          assert(std::get<0>(t) == 0);
          assert(std::get<1>(t) == nullptr);
      }
      {
      // Check that the SFINAE on the default constructor is not evaluted when
      // it isn't needed. If the default constructor is evaluted then this test
      // should fail to compile.
          IllFormedDefault v(0);
          std::tuple<IllFormedDefault> t(v);
      }
  #endif
  }
  