[boost] [mpl]iter_fold_if use of apply1 instead of iter_apply1 maybe bug?

The following code line: https://svn.boost.org/trac/boost/browser/trunk/boost/mpl/iter_fold_if.hpp#L4... shows apply1<Predicate,Iterator>; however, shouldn't this be iter_apply1<Predicate,Iterators> because, just from the name, Iterator is an iterator and needs to be deref'ed. Also, the previous line: not_< is_same<Iterator,LastIterator> > further suggests that Iterator is actually an iterator. I know it works presently; however, I really don't understand why.