The interval to create a span together with this interval.
std.datetime.date.DateTimeException if this interval is empty.
assert(Interval!Date(Date(1996, 1, 2), Date(2012, 3, 1)).span( NegInfInterval!Date(Date(1602, 5, 21))) == NegInfInterval!Date(Date(2012, 3 , 1))); assert(Interval!Date(Date(1996, 1, 2), Date(2012, 3, 1)).span( NegInfInterval!Date(Date(2013, 1, 12))) == NegInfInterval!Date(Date(2013, 1 , 12)));
Returns an interval that covers from the earliest time point of two intervals up to (but not including) the latest time point of two intervals.