/**
 * A class that extends `Error` and adds a `type` property and a `handled` flag.
 *
 * Starts with "I" to avoid conflict with built-in Error type.
 */
export declare class IError<TType> extends Error {
    readonly type: TType;
    readonly message: string;
    readonly diagnosticInfo?: string;
    handled: boolean;
    data: {
        [key: string]: unknown;
    };
    constructor({ type, message, diagnosticInfo, handled, data, }: {
        type: TType;
        message: string;
        diagnosticInfo?: string;
        handled?: boolean;
        data?: IError<TType>['data'];
    });
}
/** Use this to test if an `unknown` is probably an [[`IError`]]. */
export declare function hasIErrorProperties<TType>(obj: unknown): obj is IError<TType>;