title: Generic Parameter "T" could not be inferred
body: <p>I am trying to create a generic func that compares the identider of two models and return nil if theres no equal identifier. Here's the function.</p>
  
  <pre><code>func compareModel&lt;T: ObjectIdentifier, U: ObjectIdentifier&gt;(model: T, models: [U]) -&gt; (index: Int?, model: U?) {
  
          for (index, m) in models.enumerate() {
              if model.identifier == m.identifier {
                  return (index, m)
              }
          }
  
          return (nil, nil)
      }
  </code></pre>
  
  <p>I access it like this:</p>
  
  <pre><code>let object: (index: Int?, model: Checkout?) = self.compareModel(checkout, models: currentJoborders)
  </code></pre>
  
  <p>But I'm getting this error from the compiler.</p>
  
  <blockquote>
    <p>Generic Parameter "T" could not be inferred.</p>
  </blockquote>