I have an Angular app, when I build this app in development environment (npm run build) it works completely fine.

But when I try to build with production tag, it fails with this error:

C:/Users/1234/app/src/$$_gendir/app/app.component.ngfactory.ts (617,85): Property 'router' is private and only accessible within class 'AppComponent'.

I know router is private (in below code), but how is it working fine for development instance, and none but AppComponent.html should be able to use that?

@Component({
    selector: 'my-app',
    templateUrl: './app.component.html',
    styleUrls: ['./app.component.scss']
})

export class AppComponent {
    constructor(private router: Router, private _cookieService:CookieService) {
        //some function
    }
}