import type { Result } from './result.js';
/**
 * Replace nested Results with one `Result` of the inner value.
 *
 * Flattening only removes one level of nesting at a time
 *
 * - If given an `Ok` with a normal value, returns the `Ok` as is.
 * - If given an `Err` with a normal value, returns the `Err` as is.
 * - If given a `Result` with a `Result` value, returns the inner `Result`.
 *
 * @tags result, transform, transform-result
 * @see https://doc.rust-lang.org/core/result/enum.Result.html#method.flatten
 */
export declare function flatten<Res extends Result.Any>(value: Res): Result<Result.OkType<Res> extends Result.Any ? Result.OkType<Result.OkType<Res>> : Result.OkType<Res>, Result.ErrType<Res> extends Result.Any ? Result.ErrType<Result.ErrType<Res>> : Result.ErrType<Res>>;