import type { Result } from './result.js';
/**
 * Extract value from an `Err` or throw on an `Ok`.
 *
 * @tags result, unwrap, unsafe, errors
 * @see https://doc.rust-lang.org/core/result/enum.Result.html#method.unwrap_err
 */
export declare function unwrapErr<Res extends Result.Any>(result: Res): Result.ErrType<Res>;