/**
 * The `Feedback` class represents a feedback message that should be shown to the user.
 * - Basic `Feedback` is neither good nor bad, `Feedback` indicates good news, and `Feedback` indicates bad news.
 *
 * Conceptually different to a Javascript `Error`...
 * - `Error`: a program error designed to help developers fix an issue in their code.
 * - `Feedback`: generated in reaction to something a user did, and helps them understand what to do next.
 */
export declare class Feedback {
    /** String feedback message that is safe to show to a user. */
    readonly message: string;
    constructor(message: string);
    toString(): string;
}
/** Feedback with a known and typed `.value` field. */
export declare class ValueFeedback<T> extends Feedback {
    readonly value: T;
    constructor(message: string, value: T);
}