text: //===----------------------------------------------------------------------===//
  //
  // 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
  
  // <unordered_set>
  
  // void swap(unordered_set& c)
  //      noexcept(
  //          (!allocator_type::propagate_on_container_swap::value ||
  //           __is_nothrow_swappable<allocator_type>::value) &&
  //           __is_nothrow_swappable<hasher>::value &&
  //           __is_nothrow_swappable<key_equal>::value);
  //
  //  In C++17, the standard says that swap shall have:
  //     noexcept(allocator_traits<Allocator>::is_always_equal::value &&
  //               noexcept(swap(declval<Hash&>(), declval<Hash&>())) &&
  //               noexcept(swap(declval<Pred&>(), declval<Pred&>())));
  
  // This tests a conforming extension
  
  #include <unordered_set>
  #include <utility>
  #include <cassert>
  
  #include "test_macros.h"
  #include "MoveOnly.h"
  #include "test_allocator.h"
  
  template <class T>
  struct some_comp
  {
      typedef T value_type;
  
      some_comp() {}
      some_comp(const some_comp&) {}
      bool operator()(const T&, const T&) const { return false; }
  };
  
  template <class T>
  struct some_comp2
  {
      typedef T value_type;
  
      some_comp2() {}
      some_comp2(const some_comp2&) {}
      bool operator()(const T&, const T&) const { return false; }
  };
  
  #if TEST_STD_VER >= 14
  template <typename T>
  void swap(some_comp2<T>&, some_comp2<T>&) noexcept {}
  #endif
  
  template <class T>
  struct some_hash
  {
      typedef T value_type;
      some_hash() {}
      some_hash(const some_hash&);
      std::size_t operator()(const T&) const { return 0; }
  };
  
  template <class T>
  struct some_hash2
  {
      typedef T value_type;
      some_hash2() {}
      some_hash2(const some_hash2&);
      std::size_t operator()(const T&) const { return 0; }
  };
  
  #if TEST_STD_VER >= 14
  template <typename T>
  void swap(some_hash2<T>&, some_hash2<T>&) noexcept {}
  #endif
  
  template <class T>
  struct some_alloc
  {
      typedef T value_type;
  
      some_alloc() {}
      some_alloc(const some_alloc&);
      void deallocate(void*, unsigned) {}
  
      typedef std::true_type propagate_on_container_swap;
  };
  
  template <class T>
  struct some_alloc2
  {
      typedef T value_type;
  
      some_alloc2() {}
      some_alloc2(const some_alloc2&);
      void deallocate(void*, unsigned) {}
  
      typedef std::false_type propagate_on_container_swap;
      typedef std::true_type is_always_equal;
  };
  
  template <class T>
  struct some_alloc3
  {
      typedef T value_type;
  
      some_alloc3() {}
      some_alloc3(const some_alloc3&);
      void deallocate(void*, unsigned) {}
  
      typedef std::false_type propagate_on_container_swap;
      typedef std::false_type is_always_equal;
  };
  
  int main(int, char**)
  {
      {
          typedef std::unordered_set<MoveOnly> C;
          static_assert(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
      }
  #if defined(_LIBCPP_VERSION)
      {
          typedef std::unordered_set<MoveOnly, std::hash<MoveOnly>,
                             std::equal_to<MoveOnly>, test_allocator<MoveOnly>> C;
          static_assert(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
      }
      {
          typedef std::unordered_set<MoveOnly, std::hash<MoveOnly>,
                            std::equal_to<MoveOnly>, other_allocator<MoveOnly>> C;
          static_assert(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
      }
  #endif // _LIBCPP_VERSION
      {
          typedef std::unordered_set<MoveOnly, some_hash<MoveOnly>> C;
          static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
      }
      {
          typedef std::unordered_set<MoveOnly, std::hash<MoveOnly>,
                                                           some_comp<MoveOnly>> C;
          static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
      }
  
  #if TEST_STD_VER >= 14
      { // POCS allocator, throwable swap for hash, throwable swap for comp
      typedef std::unordered_set<MoveOnly, some_hash<MoveOnly>, some_comp <MoveOnly>, some_alloc <MoveOnly>> C;
      static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
      }
      { // always equal allocator, throwable swap for hash, throwable swap for comp
      typedef std::unordered_set<MoveOnly, some_hash<MoveOnly>, some_comp <MoveOnly>, some_alloc2<MoveOnly>> C;
      static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
      }
      { // POCS allocator, throwable swap for hash, nothrow swap for comp
      typedef std::unordered_set<MoveOnly, some_hash<MoveOnly>, some_comp2<MoveOnly>, some_alloc <MoveOnly>> C;
      static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
      }
      { // always equal allocator, throwable swap for hash, nothrow swap for comp
      typedef std::unordered_set<MoveOnly, some_hash<MoveOnly>, some_comp2<MoveOnly>, some_alloc2<MoveOnly>> C;
      static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
      }
      { // POCS allocator, nothrow swap for hash, throwable swap for comp
      typedef std::unordered_set<MoveOnly, some_hash2<MoveOnly>, some_comp <MoveOnly>, some_alloc <MoveOnly>> C;
      static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
      }
      { // always equal allocator, nothrow swap for hash, throwable swap for comp
      typedef std::unordered_set<MoveOnly, some_hash2<MoveOnly>, some_comp <MoveOnly>, some_alloc2<MoveOnly>> C;
      static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
      }
      { // POCS allocator, nothrow swap for hash, nothrow swap for comp
      typedef std::unordered_set<MoveOnly, some_hash2<MoveOnly>, some_comp2<MoveOnly>, some_alloc <MoveOnly>> C;
      static_assert( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
      }
      { // always equal allocator, nothrow swap for hash, nothrow swap for comp
      typedef std::unordered_set<MoveOnly, some_hash2<MoveOnly>, some_comp2<MoveOnly>, some_alloc2<MoveOnly>> C;
      static_assert( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
      }
  #if defined(_LIBCPP_VERSION)
      { // NOT always equal allocator, nothrow swap for hash, nothrow swap for comp
      typedef std::unordered_set<MoveOnly, some_hash2<MoveOnly>, some_comp2<MoveOnly>, some_alloc3<MoveOnly>> C;
      static_assert( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
      }
  #endif // _LIBCPP_VERSION
  #endif
  
    return 0;
  }
  