title: Synthesized Methods for Class Extension Unavailable
body: <p>OK, I'm confused. I have a class Employee, that I declare several properties for, which of course, synthesize and work fine. But in the implementation class, I extend the class like so:</p>
  
  <pre><code>@interface Employee ()
      @property (nonatomic) unsigned int employeeId;
  @end
  </code></pre>
  
  <p>which I would think would allow me to do the following in main.m:</p>
  
  <pre><code>Employee emp = [[Employee alloc] init];
  //use some other property accessor methods...
  [emp setEmployeeId:123456];
  
  //do some other stuff...
  </code></pre>
  
  <p>But the compiler chokes on the use of <code>setEmployeeId</code> with the following error <code>"No visible interface for 'Employee' declares the selector 'setEmployeeId.'</code></p>
  
  <p>Can anyone tell me why I shouldn't be able to use the extension the same way I'd use the other properties? Thanks for your help!!!</p>