{"ast_node_type":"other","tokens":[{"end":79,"kind":"keyword","start":0,"text":"(FnTrait::FnOnce,"}]}
            (FnTrait::FnOnce, sym::Output, &[FnTrait::Fn, FnTrait::FnMut][..]),
        for (fn_trait_name, output_assoc_name, subtraits) in [
            (FnTrait::AsyncFnMut, sym::CallRefFuture, &[FnTrait::AsyncFn]),