title: this class is not key value coding-compliant for the key <key> where <key> is not in the code (swift, Xcode 6)
body: <p>I have typed in a program, the code of which follows below, from a tutorial, trying to get back into coding after a number of years.</p>
  
  <p>When I run the code, everything builds, but then it crashes with subject-line error above, naming a key which does not appear anywhere in my code ("helloText"). Full error output below.</p>
  
  <p>The twist: at one point I had named one of the outlets "helloText" (now named "nameTextField").</p>
  
  <p>I have looked in every file associated with the project I could find, and could not find "helloText". I also tried the menu item "clean."</p>
  
  <p>Thanks for any guidance.</p>
  
  <pre><code>//
  //  ViewController.swift
  //  ConstructOStraws
  //
  //  Created by Eric on 11/12/14.
  //  Copyright (c) 2014 Eric. All rights reserved.
  //
  
  import UIKit
  
  class ViewController: UIViewController {
  
      override func viewDidLoad() {
          super.viewDidLoad()
          // Do any additional setup after loading the view, typically from a nib.
          setupUI()
      }
  
      override func didReceiveMemoryWarning() {
          super.didReceiveMemoryWarning()
          // Dispose of any resources that can be recreated.
      }
  
  
      @IBOutlet weak var helloLabel: UILabel!
      @IBOutlet weak var nameTextField: UITextField!
      @IBOutlet weak var helloButton: UIButton!
  
      func setupUI(){
  
          helloLabel.text = "Hello Swift!"
          helloLabel.textColor = UIColor.redColor()
          helloLabel.textAlignment = NSTextAlignment.Center
  
          nameTextField.placeholder = "Enter your name"
  
      helloButton.setTitle("Say Hell", forState: .Normal)
  
      }
  
  
      @IBAction func sayHelloAction(sender: AnyObject) {
  
          let name = nameTextField.text
  
          if name.isEmpty {
  
              let alert = UIAlertController(title: "Error", message: "Please Enter a Name.", preferredStyle: UIAlertControllerStyle.Alert)
  
              alert.addAction(UIAlertAction(title: "OK", style: UIAlertActionStyle.Default, handler: nil))
  
              self.presentViewController(alert, animated: true, completion: nil)
          } else {
  
              helloLabel.text = "Hello \(name)"
          }
      }
  
  }
  </code></pre>
  
  <p>The Errors:</p>
  
  <pre><code>2014-11-12 15:23:10.521 ConstructOStraws[2048:67817] *** Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[&lt;ConstructOStraws.ViewController 0x7f82e866b420&gt; setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key helloText.'
  *** First throw call stack:
  (
      0   CoreFoundation                      0x00000001043b7f35 __exceptionPreprocess + 165
      1   libobjc.A.dylib                     0x0000000105efbbb7 objc_exception_throw + 45
      2   CoreFoundation                      0x00000001043b7b79 -[NSException raise] + 9
      3   Foundation                          0x00000001047cf7b3 -[NSObject(NSKeyValueCoding) setValue:forKey:] + 259
      4   CoreFoundation                      0x0000000104301e80 -[NSArray makeObjectsPerformSelector:] + 224
      5   UIKit                               0x0000000104f08c7d -[UINib instantiateWithOwner:options:] + 1506
      6   UIKit                               0x0000000104d67f98 -[UIViewController _loadViewFromNibNamed:bundle:] + 242
      7   UIKit                               0x0000000104d68588 -[UIViewController loadView] + 109
      8   UIKit                               0x0000000104d687f9 -[UIViewController loadViewIfRequired] + 75
      9   UIKit                               0x0000000104d68c8e -[UIViewController view] + 27
      10  UIKit                               0x0000000104c87ca9 -[UIWindow addRootViewControllerViewIfPossible] + 58
      11  UIKit                               0x0000000104c88041 -[UIWindow _setHidden:forced:] + 247
      12  UIKit                               0x0000000104c9472c -[UIWindow makeKeyAndVisible] + 42
      13  UIKit                               0x0000000104c3f061 -[UIApplication _callInitializationDelegatesForMainScene:transitionContext:] + 2628
      14  UIKit                               0x0000000104c41d2c -[UIApplication _runWithMainScene:transitionContext:completion:] + 1350
      15  UIKit                               0x0000000104c40bf2 -[UIApplication workspaceDidEndTransaction:] + 179
      16  FrontBoardServices                  0x0000000107a9b2a3 __31-[FBSSerialQueue performAsync:]_block_invoke + 16
      17  CoreFoundation                      0x00000001042ed53c __CFRUNLOOP_IS_CALLING_OUT_TO_A_BLOCK__ + 12
      18  CoreFoundation                      0x00000001042e3285 __CFRunLoopDoBlocks + 341
      19  CoreFoundation                      0x00000001042e3045 __CFRunLoopRun + 2389
      20  CoreFoundation                      0x00000001042e2486 CFRunLoopRunSpecific + 470
      21  UIKit                               0x0000000104c40669 -[UIApplication _run] + 413
      22  UIKit                               0x0000000104c43420 UIApplicationMain + 1282
      23  ConstructOStraws                    0x00000001041d661e top_level_code + 78
      24  ConstructOStraws                    0x00000001041d665a main + 42
      25  libdyld.dylib                       0x00000001066d5145 start + 1
  )
  libc++abi.dylib: terminating with uncaught exception of type NSException
  (lldb) 
  </code></pre>