{"ast_node_type":"other","tokens":[{"end":91,"kind":"keyword","start":0,"text":"Err(guar)"}]}
                Err(guar) => self.insert_found(ty::OpaqueHiddenType::new_error(tcx, guar)),
            DefiningScopeKind::MirBorrowck => match tcx.mir_borrowck(item_def_id) {
                Ok(concrete_opaque_types) => {