                           overlap = (child_overlap == overlap) ? overlap : SOME_OVERLAP
                                }
                            }
                            node.overlaps.set(span, overlap);
                        }

                        // If all the node.overlaps are NONE_OVERLAP or ALL_OVERLAP
                        // then there's no point holding on to the children -
                        // we know all transitive children either fully overlap
                        // o