{"ast_node_type":"variable","tokens":[{"end":32,"kind":"keyword","start":0,"text":"let"}]}
        let reg = parse_reg(p)?;
    } else if eat_operand_keyword(p, exp!(Lateout), asm_macro)? {
        let expr = if p.eat_keyword(exp!(Underscore)) { None } else { Some(p.parse_expr()?) };