title: PHP: Cast variable to null
body: <p>I just stumbled upon a thing in the PHP manual that is new to me... </p>
  
  <blockquote>
    <p>Casting a variable to null will remove the variable and unset its value. (<a href="http://www.php.net/manual/en/language.types.null.php" rel="noreferrer">Source</a>)</p>
  </blockquote>
  
  <p>Now I wonder how this can be done... I tried (null) and (NULL) but it seems to be interpreted as the value null, not the type null.
  I know this question must sound ridiculous, but does somebody know how to cast to null?</p>