title: Cannot invoke initializer for type 'Range<String.Index>' with an argument list of type '(Range<String.Index>)'
body: <p>After updating to Xcode 10 beta, which apparently comes with Swift 4.1.50, I'm seeing the following error which I'm not sure how to fix:</p>
  
  <blockquote>
    <p>Cannot invoke initializer for type 'Range&lt; String.Index>' with an argument list of type '(Range&lt; String.Index>)'</p>
  </blockquote>
  
  <p>in the following function at <code>Range&lt;Index&gt;(start..&lt;self.endIndex)</code> (line 3):</p>
  
  <pre><code>func index(of aString: String, startingFrom position: Int? = 0) -&gt; String.Index? {
      let start: String.Index = self.index(self.startIndex, offsetBy: position!)
      let range: Range&lt;Index&gt; = Range&lt;Index&gt;(start..&lt;self.endIndex)
      return self.range(of: aString, options: .literal, range: range, locale: nil)?.lowerBound
  }
  </code></pre>
  
  <p>Any idea how to fix the initializer?</p>