title: Tuple parameter declaration and assignment oddity
body: <p>I can assign a tuple as follows:</p>
  
  <pre><code>var (min, max) = (1, 2)
  </code></pre>
  
  <p>But I cannot then <em>re-assign</em> as follows</p>
  
  <pre><code>(min, max) = (1, 3) //compiler error: ';' expected but '=' found
  </code></pre>
  
  <p>Instead I seem to have to do:</p>
  
  <pre><code>min = 1
  max = 3
  </code></pre>
  
  <p>Why does the latter work whereas the former does not?</p>