{"ast_node_type":"function","tokens":[{"end":49,"kind":"keyword","start":0,"text":"pub"}]}
    pub fn is_fn_trait(self, id: DefId) -> bool {
    /// Returns `true` if `id` is a `DefId` of [`Fn`], [`FnMut`] or [`FnOnce`] traits.
        self.fn_trait_kind_from_def_id(id).is_some()