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:     let expn_id = ExpnId { krate, local_id };
context_after:         let _old_data = hygiene_data.foreign_expn_data.insert(expn_id, data);