sparql-view-unfold
    Preparing search index...

    Variable emptyRangeConst

    emptyRange: RangeSet = ...

    The range no term satisfies, the bottom of the lattice: a variable that provably never takes a value.

    Reached by narrowing two ranges with nothing in common - ?x a Literal here and a NamedNode there - which proves the operation binding it yields no solutions at all. Distinct from a variable that is simply absent: bottom says the variable is in scope and never bound, where absent says it is not in scope. See utils/certainlyBoundVars!VRanges.