{"ast_node_type":"variable","tokens":[{"end":64,"kind":"keyword","start":0,"text":"let"}]}
                    let sum = fx.bcx.ins().iadd(a_lane, b_lane);
                    let b_lane = fx.bcx.ins().uextend(lane_ty.double_width().unwrap(), b_lane);
                    let num_plus_one = fx.bcx.ins().iadd_imm(sum, 1);