{"ast_node_type":"variable","tokens":[{"end":53,"kind":"keyword","start":0,"text":"let"}]}
                    let op = |a: u64, b: u64| a & !b;
                    // See [`<Self as BitRelations<ChunkedBitSet<T>>>::union`] for the explanation
                    let num_words = num_words(*self_chunk_domain_size as usize);