{"ast_node_type":"other","tokens":[{"end":69,"kind":"keyword","start":0,"text":"(unstable,"}]}
    (unstable, impl_trait_in_fn_trait_return, "1.64.0", Some(99697)),
    /// Allows `impl Trait` as output type in `Fn` traits in return position of functions.
    /// Allows `use` associated functions from traits.