Language barrier. You are grossly misunderstanding the documentation. "The set of division results" is [-inf,-1] union [1,inf]. "The smallest interval containing" this set is [-inf,inf]. It is NOT the same thing as the smallest connected component of the set.
Good news. In that case there is no bag in implementation of misconception. But misconception still exist. As a result of one of basic operator are still wrong. [-inf, inf] IS NOT [-inf, -1] U [1, inf] It should throw exception if it cannot provide correct result (intermediate situation, not applicable to usual float calculation, result is not single interval, but only single result can be returned by /= operator). We just finished a cyrcle and now we exactly where we were at very beggining :)) May be we could find a way to contact to class maintainers?