#include "expected.hpp"

struct Foo {
  Foo(int x_) : x(x_) {}
  const int x;
  Foo(Foo const&) = default;
};

int main() {
  auto x = nonstd::make_unexpected<Foo>(Foo(3));
}

In file included from main.cpp:1:
./expected.hpp:1006:9: error: failed requirement 'std17::is_swappable<Foo>::value'; 'enable_if' cannot be used to disable this declaration
        std17::is_swappable<E>::value
        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
./expected.hpp:314:31: note: expanded from macro 'nsel_REQUIRES_R'
    typename std::enable_if< (__VA_ARGS__), R>::type
                              ^~~~~~~~~~~
./expected.hpp:1176:1: note: in instantiation of template class 'nonstd::expected_lite::unexpected_type<Foo>' requested here
make_unexpected( E && value ) -> unexpected_type< typename std::decay<E>::type >
^
main.cpp:10:20: note: in instantiation of function template specialization 'nonstd::expected_lite::make_unexpected<Foo>' requested here
  auto x = nonstd::make_unexpected<Foo>(Foo(3));
                   ^
1 error generated.