libcxx/test/std/utilities/function.objects/range.cmp/not_equal_to.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 // <functional>
  12
  13 // ranges::not_equal_to
  14
  15 #include <cassert>
  16 #include <functional>
  17 #include <type_traits>
  18 #include <utility>
  19
  20 #include "test_macros.h"
  21 #include "compare_types.h"
  22 #include "MoveOnly.h"
  23 #include "pointer_comparison_test_helper.h"
  24
  25 struct NotEqualityComparable {
  26   friend bool operator==(const NotEqualityComparable&, const NotEqualityComparable&);
  27   friend bool operator!=(const NotEqualityComparable&, const NotEqualityComparable&) = delete;
  28 };
  29
  30 static_assert(!std::is_invocable_v<std::ranges::equal_to, NotEqualityComparable, NotEqualityComparable>);
  31 static_assert(!std::is_invocable_v<std::ranges::equal_to, int, MoveOnly>);
  32 static_assert(std::is_invocable_v<std::ranges::equal_to, explicit_operators, explicit_operators>);
  33
  34 static_assert(requires { typename std::ranges::not_equal_to::is_transparent; });
  35
  36 struct PtrAndNotEqOperator {
  37   constexpr operator void*() const { return nullptr; }
  38   // We *don't* want operator!= to be picked here.
  39   friend constexpr bool operator!=(PtrAndNotEqOperator, PtrAndNotEqOperator) { return true; }
  40 };
  41
  42 constexpr bool test() {
  43   auto fn = std::ranges::not_equal_to();
  44
  45   assert(fn(MoveOnly(41), MoveOnly(42)));
  46
  47   // These are the opposite of other tests.
  48   ForwardingTestObject a;
  49   ForwardingTestObject b;
  50   assert(fn(a, b));
  51   assert(!fn(std::move(a), std::move(b)));
  52
  53   assert(fn(1, 2));
  54   assert(!fn(2, 2));
  55   assert(fn(2, 1));
  56
  57   assert(fn(2, 1L));
  58
  59   // Make sure that "ranges::equal_to(x, y) == !ranges::not_equal_to(x, y)", even here.
  60   assert(!fn(PtrAndNotEqOperator(), PtrAndNotEqOperator()));
  61   assert(std::ranges::equal_to()(PtrAndNotEqOperator(), PtrAndNotEqOperator()));
  62
  63   return true;
  64 }
  65
  66 int main(int, char**) {
  67
  68   test();
  69   static_assert(test());
  70
  71   // test total ordering of int* for not_equal_to<int*> and not_equal_to<void>.
  72   do_pointer_comparison_test(std::ranges::not_equal_to());
  73
  74   return 0;
  75 }