title: Swift - Expression resolves to an unused l-value
body: <p>Arrays stockPriceDate1..4 are used identically throughout the code. Get l-value error on last two entries. It is my list punctuation that I have got wrong?</p>
  
  <pre><code>func sChart(chart: ShinobiChart!, dataPointAtIndex dataIndex: Int, forSeriesAtIndex seriesIndex: Int) -&gt; SChartData! {
      return seriesIndex == 0 ?
          stockPriceData1[dataIndex]: 
          stockPriceData2[dataIndex]; 
          stockPriceData3[dataIndex];    &lt;- Expression resolves error...
          stockPriceData4[dataIndex]     &lt;- Expression resolves error...
  }
  </code></pre>