{

typedef iterator_traits<ForwardIterator1> traits1;

typedef typename traits1::value_type v1;

typedef typename traits1::reference r1;

typedef iterator_traits<ForwardIterator2> traits2;

typedef typename traits2::value_type v2;

typedef typename traits2::reference r2;

bool const use_swap = boost::is_same<v1,v2>::value

&& boost::is_reference<r1>::value

&& boost::is_reference<r2>::value;

iter_swap_impl<use_swap>::do_it(*i1,*i2);

{

typename

iterator_traits<ForwardIterator1>::value_type

tmp = *i1;

*i1 = *i2;

*i2 = tmp;