libstdc++-v3/testsuite/18_support/coroutines/lwg3460.cc

   1 // Copyright (C) 2020-2024 Free Software Foundation, Inc.
   2 //
   3 // This file is part of the GNU ISO C++ Library.  This library is free
   4 // software; you can redistribute it and/or modify it under the
   5 // terms of the GNU General Public License as published by the
   6 // Free Software Foundation; either version 3, or (at your option)
   7 // any later version.
   8
   9 // This library is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13
  14 // You should have received a copy of the GNU General Public License along
  15 // with this library; see the file COPYING3.  If not see
  16 // <http://www.gnu.org/licenses/>.
  17
  18 // { dg-do compile { target c++20 } }
  19
  20 #include <coroutine>
  21
  22 void
  23 test01()
  24 {
  25   // LWG 3460. Unimplementable noop_coroutine_handle guarantees
  26
  27   static_assert( std::is_convertible_v<std::noop_coroutine_handle&,
  28                                        std::coroutine_handle<>> );
  29   static_assert( ! std::is_convertible_v<std::noop_coroutine_handle&,
  30                                          std::coroutine_handle<>&> );
  31   static_assert( ! std::is_assignable_v<std::noop_coroutine_handle&,
  32                                         std::coroutine_handle<>> );
  33
  34   std::noop_coroutine_handle h = std::noop_coroutine();
  35   std::coroutine_handle<> h2 = h;
  36   h2();         // no-op
  37   h2.resume();  // no-op
  38   h2.destroy(); // no-op
  39 }
  40
  41 void
  42 test02()
  43 {
  44   // LWG 3469. Precondition of coroutine_handle::promise may be insufficient
  45
  46   struct P1 { };
  47   struct P2 { };
  48
  49   static_assert( ! std::is_assignable_v<std::coroutine_handle<P1>&,
  50                                         std::coroutine_handle<>> );
  51   static_assert( ! std::is_assignable_v<std::coroutine_handle<P1>&,
  52                                         std::coroutine_handle<P2>> );
  53 }