title: Replacing an if statement with a disjunction
body: <p>Just for fun, I was trying to replace:</p>
  
  <pre><code>if (set1.add(x) == false)
  {
      set2.add(x);
  }
  </code></pre>
  
  <p>with:</p>
  
  <pre><code>set1.add(x) || set2.add(x);
  </code></pre>
  
  <p>However, Eclipse complains:</p>
  
  <pre><code>Syntax error on token "||", invalid AssignmentOperator
  The left-hand side of an assignment must be a variable
  </code></pre>
  
  <p>Could anybody shine some light onto these error messages? They don't make much sense to me.</p>