syntax_data: {"ast_node_type":"other","tokens":[{"end":38,"kind":"keyword","start":0,"text":"HygieneData::with(|hygiene_data|"}]}
source_snippet:     HygieneData::with(|hygiene_data| {
context_before: pub fn register_local_expn_id(data: ExpnData, hash: ExpnHash) -> ExpnId {
context_after:         let expn_id = hygiene_data.local_expn_data.next_index();