libcxx/test/std/iterators/predef.iterators/iterators.common/ctor.default.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 // constexpr common_iterator() requires default_initializable<I> = default;
  12
  13 #include <iterator>
  14 #include <cassert>
  15
  16 #include "test_iterators.h"
  17
  18 constexpr bool test()
  19 {
  20   {
  21     using It = cpp17_input_iterator<int*>;
  22     using CommonIt = std::common_iterator<It, sentinel_wrapper<It>>;
  23     static_assert(!std::is_default_constructible_v<It>); // premise
  24     static_assert(!std::is_default_constructible_v<CommonIt>); // conclusion
  25   }
  26   {
  27     // The base iterator is value-initialized.
  28     std::common_iterator<int*, sentinel_wrapper<int*>> c;
  29     assert(c == nullptr);
  30   }
  31
  32   return true;
  33 }
  34
  35 int main(int, char**) {
  36   test();
  37   static_assert(test());
  38
  39   return 0;
  40 }