{"ast_node_type":"other","tokens":[{"end":43,"kind":"keyword","start":0,"text":"opaque_type_key.def_id,"}]}
                    opaque_type_key.def_id,
                self.typeck_results.concrete_opaque_types.insert(
                    ty::OpaqueHiddenType::new_error(tcx, err.report(self.fcx)),