declare namespace Ext {
    export namespace form {
        export interface FieldAncestorConfig {
            fieldDefaults?: object;
        }

        export class FieldAncestor extends Ext.Mixin  {
            public initFieldAncestor(): void;
            public onFieldErrorChange(field?: Ext.form.Labelable, error?: string): void;
            public onFieldValidityChange(field?: Ext.form.field.Field, valid?: boolean): void;
        }
    }
}