text: /* Unit testing for outcomes
  (C) 2013-2019 Niall Douglas <http://www.nedproductions.biz/> (9 commits)
  
  
  Boost Software License - Version 1.0 - August 17th, 2003
  
  Permission is hereby granted, free of charge, to any person or organization
  obtaining a copy of the software and accompanying documentation covered by
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  the above license grant, this restriction and the following disclaimer,
  must be included in all copies of the Software, in whole or in part, and
  all derivative works of the Software, unless such copies or derivative
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  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
  SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
  FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
  ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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  */
  
  #include <boost/outcome/outcome.hpp>
  #include <boost/test/unit_test.hpp>
  #include <boost/test/unit_test_monitor.hpp>
  
  BOOST_OUTCOME_AUTO_TEST_CASE(works_outcome_constexpr, "Tests that outcome works as intended in a constexpr evaluation context")
  {
    using namespace BOOST_OUTCOME_V2_NAMESPACE;
  
    static_assert(std::is_literal_type<result<int, void, void>>::value, "result<int, void, void> is not a literal type!");
    static_assert(std::is_literal_type<outcome<int, void, void>>::value, "outcome<int, void, void> is not a literal type!");
  
    // Unfortunately result<T> can never be a literal type as error_code can never be literal
    //
    // It can however be trivially destructible as error_code is trivially destructible. That
    // makes possible lots of compiler optimisations
    static_assert(std::is_trivially_destructible<result<int>>::value, "result<int> is not trivially destructible!");
    static_assert(std::is_trivially_destructible<result<void>>::value, "result<void> is not trivially destructible!");
  
    // outcome<T> default has no trivial operations, but if configured it can become so
    static_assert(std::is_trivially_destructible<outcome<int, boost::system::error_code, void>>::value, "outcome<int, boost::system::error_code, void> is not trivially destructible!");
  
    {
      // Test compatible results can be constructed from one another
      constexpr result<int, long> g(in_place_type<int>, 5);
      constexpr result<long, int> g2(g);
      static_assert(g.has_value(), "");
      static_assert(!g.has_error(), "");
      static_assert(g.assume_value() == 5, "");  // value() with UDT E won't compile
      static_assert(g2.has_value(), "");
      static_assert(!g2.has_error(), "");
      static_assert(g2.assume_value() == 5, "");  // value() with UDT E won't compile
      constexpr result<void, int> g3(in_place_type<void>);
      constexpr result<long, int> g4(g3);
      constexpr result<int, void> g5(in_place_type<void>);
      constexpr result<long, int> g6(g5);
      (void) g4;
      (void) g6;
  
      // Test void
      constexpr result<void, int> h(in_place_type<void>);
      static_assert(h.has_value(), "");
      constexpr result<int, void> h2(in_place_type<void>);
      static_assert(!h2.has_value(), "");
      static_assert(h2.has_error(), "");
  
      // Test const
      constexpr result<const int, void> i(5);
      constexpr result<const int, void> i2(i);
      (void) i2;
    }
    {
      // Test compatible outcomes can be constructed from one another
      constexpr outcome<int, long, char *> g(in_place_type<int>, 5);
      constexpr outcome<long, int, const char *> g2(g);
      static_assert(g.has_value(), "");
      static_assert(!g.has_error(), "");
      static_assert(!g.has_exception(), "");
      static_assert(g.assume_value() == 5, "");  // value() with UDT E won't compile
      static_assert(g2.has_value(), "");
      static_assert(!g2.has_error(), "");
      static_assert(!g2.has_exception(), "");
      static_assert(g2.assume_value() == 5, "");  // value() with UDT E won't compile
      constexpr outcome<void, int, char *> g3(in_place_type<void>);
      constexpr outcome<long, int, const char *> g4(g3);
      constexpr outcome<int, void, char *> g5(in_place_type<void>);
      constexpr outcome<long, int, const char *> g6(g5);
      (void) g4;
      (void) g6;
    }
  }
  