import { FormGroupDirective, NgControl, NgForm } from '@angular/forms';
import { ErrorStateMatcher } from '@angular/material/core';
import { Subject } from "rxjs";
/** @docs-private */
export declare class FileInputBase {
    _defaultErrorStateMatcher: ErrorStateMatcher;
    _parentForm: NgForm;
    _parentFormGroup: FormGroupDirective;
    ngControl: NgControl;
    errorState: boolean;
    stateChanges: Subject<void>;
    constructor(_defaultErrorStateMatcher: ErrorStateMatcher, _parentForm: NgForm, _parentFormGroup: FormGroupDirective, ngControl: NgControl);
    updateErrorState(): void;
}