import { BaseError } from 'make-error';
import { Constrained } from '../../core';
export declare class InvalidLocaleError extends BaseError {
    constructor();
}
export declare const localeSymbol: unique symbol;
export type Locale = Constrained<typeof localeSymbol, string>;
export declare function isLocale(input: unknown): input is Locale;
export declare function locale(input: unknown): Locale;