{"ast_node_type":"other","tokens":[{"end":95,"kind":"keyword","start":0,"text":"args.get(index).and_then(|arg|"}]}
                                args.get(index).and_then(|arg| arg.as_region()).unwrap_or_else(
                                let index = generics.param_def_id_to_index[&param_def_id] as usize;
                                    || {