import { Subject } from 'rxjs';
import { OnDestroy } from '@angular/core';
import * as i0 from "@angular/core";
export declare class UiMatFormFieldRequiredIntl implements OnDestroy {
    /**
     * Notify if changes have occured that require that the labels be updated.
     *
     */
    changes: Subject<void>;
    tooltipMessage: string;
    ngOnDestroy(): void;
    static ɵfac: i0.ɵɵFactoryDeclaration<UiMatFormFieldRequiredIntl, never>;
    static ɵprov: i0.ɵɵInjectableDeclaration<UiMatFormFieldRequiredIntl>;
}