import { Block } from "../../types/types";
/**
 * Throws an error with a default panic message.
 */
export declare function panic(): void;
/**
 * Throws an error with a specified **message**.
 */
export declare function panic(message: string): void;
/**
 * Immediately invokes a **block** callback. If the **block** throws an error the error will be returned. Returns
 * null otherwise.
 */
export declare function snag<T extends Error>(block: Block): T | null;