title: If Array.append has not mutable arguments partially applied then the lambda can be removed
body: <p>I have Array of Array of strings. I need to flatten them and I use:</p>
  
  <pre><code>Array.fold (fun acc el -&gt; Array.append acc el) [||] arr2d
  </code></pre>
  
  <p>Lint says me that:</p>
  
  <blockquote>
    <p>"If Array.append has not mutable arguments partially applied then the
    lambda can be removed"</p>
  </blockquote>
  
  <p>What does it mean? How can I remove lambda?</p>