#ifdef BOOST_ADL_WORKAROUND_
namespace boost_noncopyable  // protection from unintended ADL
{
  class noncopyable
  {
   protected:
      noncopyable() {}
      ~noncopyable() {}
   private:  // emphasize the following members are private
      noncopyable( const noncopyable& );
      const noncopyable& operator=( const noncopyable& );
  };
}

namespace boost {
typedef boost_noncopyable::noncopyable noncopyable;
}
#else
#include "boost/noncopyable.hpp"           
#endif

namespace metal {
  class gold : private boost::noncopyable
  {
  };
}

namespace boost {
  void find_metal(const metal::gold&) {
  }
}

int main() {
  metal::gold coin;
  find_metal(coin);
  return 0;
}