title: Any way to print all nil objects in scope?
body: <p>I frequently encounter erroneous <code>nil</code> values when running tests. In order to find the problem, I end up inserting a bunch of lines like:</p>
  
  <pre><code>puts 'variable x is nil' if x.nil?
  puts 'variable y is nil' if y.nil?
  ...
  </code></pre>
  
  <p>Which slowly gets me closer to the problem.  Is there a gem or something that can quickly print a list of all <code>nil</code> variables in the current scope?  Or some method of debugging my methods that's a little less laborious?</p>