Interval.Union produces wrong bounds when one interval is unbounded

[andrew]

In Interval.Union, when one interval has an unbounded min (empty string) and the other has a concrete min, the code takes the concrete value instead of keeping it unbounded:

} else if i.Min == "" {
    result.Min = other.Min // should stay "" (unbounded)

Same for max in the reverse direction. The union of (-inf, 2.0] and [1.0, +inf) should be (-inf, +inf), but currently produces [1.0, 2.0].