syntax_data: {"ast_node_type":"other","tokens":[{"end":94,"kind":"keyword","start":0,"text":"self.local_expn_data[expn_id].as_ref().expect(\"no"}]}
source_snippet:         self.local_expn_data[expn_id].as_ref().expect("no expansion data for an expansion ID")
context_before:     fn local_expn_data(&self, expn_id: LocalExpnId) -> &ExpnData {
context_after:     }