title: Error: The instance member ... can't be accessed in an initializer
body: <p>Why does this code:</p>
  <pre class="lang-dart prettyprint-override"><code>class _SequentialTextPageState {
    String jsonTextPref = 'seqtext';
    int jsonTextSuff = 10;
    String jsonText = jsonTextPref + jsonTextSuff.toString();
  }
  </code></pre>
  <p>generate these errors?</p>
  <pre class="lang-none prettyprint-override"><code>Error: The instance member 'jsonTextPref' can't be accessed in an initializer.
  
  Error: The instance member 'jsonTextSuff' can't be accessed in an initializer.
  </code></pre>
  <p>It seems to me that concatenation between <code>String</code> and <code>int</code> is correct?</p>