ps(node, file, coverage.c, from, to);

                        // Gather all the spans used by the children.
                        let all_spans = new Set();
                        for (const [_, child] of node.children) {
                            for (const [span, _] of child.overlaps) {
                                all_spans.add(span);
                            }
                        }

                        // Update the node.overlaps based on the child overlaps.
                        f