libcxx/test/std/containers/sequences/vector/vector.special/swap_noexcept.compile.pass.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
  10
  11 // <vector>
  12
  13 // void swap(vector& c)
  14 //     noexcept(!allocator_type::propagate_on_container_swap::value ||
  15 //              __is_nothrow_swappable<allocator_type>::value);
  16 //
  17 //  In C++17, the standard says that swap shall have:
  18 //     noexcept(allocator_traits<Allocator>::propagate_on_container_swap::value ||
  19 //              allocator_traits<Allocator>::is_always_equal::value);
  20
  21 // This tests a conforming extension
  22
  23 #include <vector>
  24 #include <utility>
  25 #include <cassert>
  26
  27 #include "test_macros.h"
  28 #include "MoveOnly.h"
  29 #include "test_allocator.h"
  30
  31 template <class T>
  32 struct some_alloc
  33 {
  34     typedef T value_type;
  35
  36     some_alloc() {}
  37     some_alloc(const some_alloc&);
  38     void allocate(std::size_t);
  39     void deallocate(void*, unsigned) {}
  40
  41     typedef std::true_type propagate_on_container_swap;
  42 };
  43
  44 template <class T>
  45 struct some_alloc2
  46 {
  47     typedef T value_type;
  48
  49     some_alloc2() {}
  50     some_alloc2(const some_alloc2&);
  51     void allocate(std::size_t);
  52     void deallocate(void*, unsigned) {}
  53
  54     typedef std::false_type propagate_on_container_swap;
  55     typedef std::true_type is_always_equal;
  56 };
  57
  58 void test()
  59 {
  60     {
  61         typedef std::vector<MoveOnly> C;
  62         static_assert(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
  63     }
  64 #if defined(_LIBCPP_VERSION)
  65     {
  66         typedef std::vector<MoveOnly, test_allocator<MoveOnly>> C;
  67         static_assert(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
  68     }
  69 #endif
  70     {
  71         typedef std::vector<MoveOnly, other_allocator<MoveOnly>> C;
  72         static_assert(noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
  73     }
  74     {
  75         typedef std::vector<MoveOnly, some_alloc<MoveOnly>> C;
  76 #if TEST_STD_VER >= 14
  77         //  In C++14, if POCS is set, swapping the allocator is required not to throw
  78         static_assert( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
  79 #else
  80         static_assert(!noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
  81 #endif
  82     }
  83 #if TEST_STD_VER >= 14
  84     {
  85         typedef std::vector<MoveOnly, some_alloc2<MoveOnly>> C;
  86         // If the allocators are always equal, then the swap can be noexcept
  87         static_assert( noexcept(swap(std::declval<C&>(), std::declval<C&>())), "");
  88     }
  89 #endif
  90 }