{"ast_node_type":"variable","tokens":[{"end":99,"kind":"keyword","start":0,"text":"let"}]}
                                let index = generics.param_def_id_to_index[&param_def_id] as usize;
                            ObjectLifetimeDefault::Param(param_def_id) => {
                                args.get(index).and_then(|arg| arg.as_region()).unwrap_or_else(