title: Can I destructure (pattern extract) a Scala list into a reused var?
body: <p>I have a Scala list. I can destructure the list into some variables thus:</p>
  
  <pre><code>var a :: b :: tail = myList
  a should be ("A1")
  b should be ("B1")
  tail should be ('empty)
  </code></pre>
  
  <p>However, I do not seem to be able to reuse the same variables for another destructuring:</p>
  
  <pre><code>a :: b :: tail = anotherList
  a should be ("A2")
  b should be ("B2")
  tail should be ('empty)
  </code></pre>
  
  <p>The compiler tells me that it expected a semi-colon but found an equals sign. Why is this? 
  Is it impossible to use already-declared variables when destructuring? Am I doing something stupid?</p>