In http://ruby-doc.org/core-1.8.7/Range.html it says:
Ranges can be constructed using objects of any type, as long as the
objects can be compared using their <=> operator and they support the
succ method to return the next object in sequence.
In http://ruby-doc.org/core-1.9.3/Range.html the above statement seems
to have disappeared. Has the semantics changed?