title: Cannot apply addConstraints:NSLayoutConstraint to self.window
body: <p>I am trying to add background to status bar.</p>
  
  <p>When i try to add VFL constraint to self.window i get error <strong>unexpected interface name: 'NSLayoutConstratint'</strong></p>
  
  <pre><code>- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
      // Override point for customization after application launch.
  
      UIScreen *screen=[[UIScreen alloc]init];
  
      UIWindow *window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
  
  
      self.window.makeKeyAndVisible;
  
      application.statusBarStyle = UIStatusBarStyleLightContent;
  
      UIView *statusBarBackgroundView = [[UIView alloc]init];
      statusBarBackgroundView.backgroundColor = [UIColor colorWithRed:194/255 green:31/255 blue:31/255 alpha:1];
  
      [self.window addSubview:statusBarBackgroundView];
  
  // Error while adding constraint below
  
      [self.window addConstraints:NSLayoutConstraint
      constraintsWithVisualFormat:@"H:|[statusBarBackgroundView]|"
                          options:0
                          metrics:nil
                            views:NSDictionaryOfVariableBindings(statusBarBackgroundView)];
  </code></pre>