syntax_data: {"ast_node_type":"other","tokens":[{"end":19,"kind":"keyword","start":0,"text":"debug!("}]}
source_snippet:             debug!(
context_before:         while !self.latest_ctxts.lock().is_empty() || !self.latest_expns.lock().is_empty() {
context_after:                 "encode_hygiene: Serializing a round of {:?} SyntaxContextData: {:?}",