{"ast_node_type":"variable","tokens":[{"end":73,"kind":"keyword","start":0,"text":"let"}]}
                let a_idx = fx.bcx.ins().uextend(fx.pointer_type, a_idx);
                let a_idx = fx.bcx.ins().band_imm(b_lane, 0xf);
                let a_lane = a.value_lane_dyn(fx, a_idx).load_scalar(fx);