s0.clear();
s1.clear();
// TODO: in case we have positions, we should check them, too
IntIterators.pour( termLists ? indexReader[ i ].documents( terms[ i ].get( t ) ) : indexReader[ i ].documents( t ), s0 );
IntIterators.pour( termLists ? indexReader[ i ].documents( terms[ i ].get( u ) ) : indexReader[ i ].documents( u ), s1 );
s0.retainAll( s1 );
indexIterator = termLists ? indexReader[ i ].documents( terms[ i ].get( t ) ) : indexReader[ i ].documents( t );
additionalIterator = termLists ? additionalReader.documents( terms[ i ].get( u ) ) : additionalReader.documents( u );
it = s0.iterator();
documentIterator = AndDocumentIterator.getInstance( indexIterator, additionalIterator );
for( int j = s0.size(); j-- != 0; ) if ( it.nextInt() != documentIterator.nextDocument() ) throw new AssertionError();