{"ast_node_type":"function","tokens":[{"end":100,"kind":"keyword","start":0,"text":"pub"}]}
    pub fn hir_opt_const_param_default_param_def_id(self, anon_const: HirId) -> Option<LocalDefId> {
    /// called with the HirId for the `{ ... }` anon const
        let const_arg = self.parent_hir_id(anon_const);