syntax_data: {"ast_node_type":"variable","tokens":[{"end":61,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:         let _eid = hygiene_data.local_expn_hashes.push(hash);
context_before:         hygiene_data.local_expn_data.push(Some(data));
context_after:         debug_assert_eq!(expn_id, _eid);