{"ast_node_type":"variable","tokens":[{"end":83,"kind":"keyword","start":0,"text":"let"}]}
    let (ret_lane_count, ret_lane_ty) = ret.layout().ty.simd_size_and_type(fx.tcx);
    let (src_lane_count, src_lane_ty) = layout.ty.simd_size_and_type(fx.tcx);
    assert_eq!(src_lane_ty, ret_size.src_ty(fx.tcx));