{"ast_node_type":"variable","tokens":[{"end":70,"kind":"keyword","start":0,"text":"let"}]}
    let from_regsave = bx.append_sibling_block("va_arg.from_regsave");
    let from_stack = bx.append_sibling_block("va_arg.from_stack");
    let end = bx.append_sibling_block("va_arg.end");