syntax_data: {"ast_node_type":"other","tokens":[{"end":16,"kind":"keyword","start":0,"text":"}"}]}
source_snippet:         } else {
context_before:             self.local_expn_data[expn_id].as_ref().expect("no expansion data for an expansion ID")
context_after:             &self.foreign_expn_data[&expn_id]