libcxx/test/std/iterators/iterator.requirements/alg.req.permutable/permutable.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, c++11, c++14, c++17
  10
  11 // template<class I>
  12 //   concept permutable = see below; // Since C++20
  13
  14 #include <iterator>
  15
  16 #include "test_iterators.h"
  17
  18 using AllConstraintsSatisfied = forward_iterator<int*>;
  19 static_assert( std::forward_iterator<AllConstraintsSatisfied>);
  20 static_assert( std::indirectly_movable_storable<AllConstraintsSatisfied, AllConstraintsSatisfied>);
  21 static_assert( std::indirectly_swappable<AllConstraintsSatisfied>);
  22 static_assert( std::permutable<AllConstraintsSatisfied>);
  23
  24 using NotAForwardIterator = cpp20_input_iterator<int*>;
  25 static_assert(!std::forward_iterator<NotAForwardIterator>);
  26 static_assert( std::indirectly_movable_storable<NotAForwardIterator, NotAForwardIterator>);
  27 static_assert( std::indirectly_swappable<NotAForwardIterator>);
  28 static_assert(!std::permutable<NotAForwardIterator>);
  29
  30 struct NonCopyable {
  31   NonCopyable(const NonCopyable&) = delete;
  32   NonCopyable& operator=(const NonCopyable&) = delete;
  33   friend void swap(NonCopyable&, NonCopyable&);
  34 };
  35 using NotIMS = forward_iterator<NonCopyable*>;
  36
  37 static_assert( std::forward_iterator<NotIMS>);
  38 static_assert(!std::indirectly_movable_storable<NotIMS, NotIMS>);
  39 static_assert( std::indirectly_swappable<NotIMS>);
  40 static_assert(!std::permutable<NotIMS>);
  41
  42 // Note: it is impossible for an iterator to satisfy `indirectly_movable_storable` but not `indirectly_swappable`:
  43 // `indirectly_swappable` requires both iterators to be `indirectly_readable` and for `ranges::iter_swap` to be
  44 // well-formed for both iterators. `indirectly_movable_storable` also requires the iterator to be `indirectly_readable`.
  45 // `ranges::iter_swap` is always defined for `indirectly_movable_storable` iterators.