{"ast_node_type":"variable","tokens":[{"end":76,"kind":"keyword","start":0,"text":"let"}]}
                    let a_lane = a.value_lane(fx, lane_idx).load_scalar(fx);
                for lane_idx in out_lane_idx * 8..out_lane_idx * 8 + 8 {
                    let a_lane = fx.bcx.ins().uextend(types::I16, a_lane);