title: Cannot assign property in method of struct
body: <p>In Swift, I'm trying to do the following:</p>
  
  <pre><code>struct Foo {
      var bar = 1
  
      func baz() {
          bar = 2
      }
  }
  </code></pre>
  
  <p>Xcode reports the error <code>Cannot assign to 'bar' in self</code> on the line in the method.</p>
  
  <p>Why? If I change the struct to a class, there's no error.</p>