{"ast_node_type":"other","tokens":[{"end":55,"kind":"keyword","start":0,"text":"(unstable,"}]}
    (unstable, unboxed_closures, "1.0.0", Some(29625)),
    /// Allows using the `rust-call` ABI.
    // !!!!    !!!!    !!!!    !!!!   !!!!    !!!!    !!!!    !!!!    !!!!    !!!!    !!!!