title: Instance member cannot be used on type
body: <p>I have the following class:</p>
  
  <pre><code>class ReportView: NSView {  
      var categoriesPerPage = [[Int]]()
      var numPages: Int = { return categoriesPerPage.count }
  }
  </code></pre>
  
  <p>Compilation fails with the message:</p>
  
  <blockquote>
    <p>Instance member 'categoriesPerPage' cannot be used on type
    'ReportView'</p>
  </blockquote>
  
  <p>What does this mean? </p>