syntax_data: {"ast_node_type":"other","tokens":[{"end":85,"kind":"keyword","start":0,"text":"leaf_candidate.match_pairs.extend(remaining_match_pairs.iter().cloned());"}]}
source_snippet:             leaf_candidate.match_pairs.extend(remaining_match_pairs.iter().cloned());
context_before:             assert!(leaf_candidate.match_pairs.is_empty());