{"ast_node_type":"variable","tokens":[{"end":77,"kind":"keyword","start":0,"text":"let"}]}
    let high = fx.bcx.ins().band_imm(high, 0x7fff_ffff_ffff_ffff_u64 as i64);
    let (low, high) = fx.bcx.ins().isplit(bits);
    let bits = fx.bcx.ins().iconcat(low, high);