import { FormGroupDirective, NgForm, FormControl, NgControl } from '@angular/forms';
import { Subject } from 'rxjs';
import * as i0 from "@angular/core";
export declare type Constructor<T> = new (...args: any[]) => T;
/** Error state matcher that matches when a control is invalid and dirty. */
export declare class ShowOnDirtyErrorStateMatcher implements ErrorStateMatcher {
    isError(control: FormControl | null, form: FormGroupDirective | NgForm | null): boolean;
    static ɵfac: i0.ɵɵFactoryDef<ShowOnDirtyErrorStateMatcher, never>;
    static ɵprov: i0.ɵɵInjectableDef<ShowOnDirtyErrorStateMatcher>;
}
/** Provider that defines how form controls behave with regards to displaying error messages. */
export declare class ErrorStateMatcher {
    isError(control: FormControl | null, form: FormGroupDirective | NgForm | null): boolean;
    static ɵfac: i0.ɵɵFactoryDef<ErrorStateMatcher, never>;
    static ɵprov: i0.ɵɵInjectableDef<ErrorStateMatcher>;
}
export interface CanUpdateErrorState {
    readonly stateChanges: Subject<void>;
    isError: boolean;
    errorStateMatcher: ErrorStateMatcher;
    isErrorStateFrozen: boolean;
    updateIsError(): any;
}
export interface HasErrorState {
    _parentFormGroup: FormGroupDirective;
    _defaultErrorStateMatcher: ErrorStateMatcher;
    ngControl: NgControl;
}
/**
 * Mixin to augment a directive with updateErrorState method.
 * For component with `errorState` and need to update `errorState`.
 */
export declare function mixinIsError<T extends Constructor<HasErrorState>>(base: T): Constructor<CanUpdateErrorState> & T;