scala/scala — pull request #1140 by soc (2012-08-14 20:43:58+00:00)
Title: SI-6167 Override SeqLike#isEmpty for better performance

This results in a faster Vector#isEmpty (and head, tail, last, init)
because it avoids building a VectorIterator just to check if
iterator.hasNext is false.
Other classes which have not overridden the implementation of SeqLike
also benefit from it.