syntax_data: {"ast_node_type":"variable","tokens":[{"end":62,"kind":"keyword","start":0,"text":"let"}]}
source_snippet:             let _eid = data.local_expn_hashes.push(expn_hash);
context_before:             let expn_id = data.local_expn_data.push(Some(expn_data));
context_after:             debug_assert_eq!(expn_id, _eid);