{"ast_node_type":"other","tokens":[{"end":75,"kind":"keyword","start":0,"text":"}"}]}
            } else if self.tcx.is_diagnostic_item(sym::Option, adt.did()) {
                ("a", "Result", "Err", ret_ty_matches(sym::Result))
                ("an", "Option", "None", ret_ty_matches(sym::Option))