{"ast_node_type":"variable","tokens":[{"end":62,"kind":"keyword","start":0,"text":"let"}]}
        let closure_expr_def_id = self.cx.body_owner_def_id();
    fn cat_upvar(&self, hir_id: HirId, var_id: HirId) -> Result<PlaceWithHirId<'tcx>, Cx::Error> {