#include <utility>
 
// Note: I've revised my implementation of AUTO_FUN here
// to make its use look more like a function definition
 
#define AUTO_FUN_IMPL( ... ) decltype( __VA_ARGS__ ) { return __VA_ARGS__; }
 
#define AUTO_FUN( name_and_param_list ) auto name_and_param_list-> AUTO_FUN_IMPL
 
template< typename SourceType >
SourceType&& multi_cast( SourceType&& source )
{
  return source;
}
 
template< typename    TargetType
        , typename... IntermediateTypes
        , typename    SourceType
        >
AUTO_FUN( multi_cast( SourceType&& source ) )
(
  static_cast< TargetType >
  ( multi_cast< IntermediateTypes... >
    ( std::forward< SourceType >( source ) )
  )
)
 
////////////////////
// Example usage: //
////////////////////
struct left {};
struct right {};
struct child : left, right {};
 
int main()
{
  child child_;
  left& left_ = child_;
  right& right_ = multi_cast< right&, child& >( left_ );
}