 MemRegions, Symbols, or concrete 
values (e.g., the number 1).
</p>

  <!-- 
  TODO: Add a picture.
  <br>
  Symbols<br>
  FunctionalObjects are used throughout.  
  -->

<h2 id=idea>Idea for a Checker</h2>
  Here are several questions which you should consider when evaluating your 
  checker idea:
  <ul>
    <li>Can the check be effectively implemented without path-sensitive 
    analysis? See <a href="#ast">AST Visitors</a>.</li>
    
    <li>How high the false positive rate is going to be? Looking at th