title: Swift Cannot invoke 'find' with an argument list of type '([Score], Score)' where Score is a struct
body: <p>While <code>find(["a", "b"], "c")</code> works with no problems, I get an error when trying to find the index of a structure inside an array of structures:</p>
  
  <pre><code>struct Score
  {
      //...
  }
  
  var scores: [Score] = //...
  var score: Score = //...
  
  find(self.scores, score) // Error: Cannot invoke 'find' with an argument list of type '([Score], Score)'
  </code></pre>
  
  <p>I though it could be a problem with structures that can't be compared to each other by default. But changing <code>Score</code>s definition to <code>class</code>
   gives me the same error.</p>