{"ast_node_type":"other","tokens":[{"end":57,"kind":"keyword","start":0,"text":"DefiningTy::Closure(def_id,"}]}
                DefiningTy::Closure(def_id, _) => def_id,
            let def_id = match self.regioncx.universal_regions().defining_ty {
                ty => bug!("unexpected DefiningTy {:?}", ty),