{"ast_node_type":"variable","tokens":[{"end":71,"kind":"keyword","start":0,"text":"let"}]}
                    let idx = prop.get_const(idx.into())?.immediate()?;
                (PlaceElem::Index(idx), Value::Aggregate { fields, .. }) => {
                    let idx = prop.ecx.read_target_usize(idx).discard_err()?.try_into().ok()?;