title: Variable optimized away by compiler
body: <p>I started debugging some code attempting to find my mistake. When I attempt to <code>p tlEntries</code> from the debugger I get the</p>
  
  <p><code>&lt;variable optimized away by compiler&gt;</code></p>
  
  <p>message while stopped on the <code>if</code> statement.  The following is my code:</p>
  
  <pre><code>NSArray *tlEntries = [[NSArray alloc] initWithArray:[self fetchJSONValueForURL:url]];
  for (NSDictionary *info in tlEntries) 
  {
      if ([info objectForKey:@"screen_name"] != nil)
           NSLog(@"Found %@ in the timeline", [info objectForKey:@"screen_name"]);
  }
  </code></pre>
  
  <p>Earlier debugging gives me confidence the URL is indeed returning a valid <code>NSArray</code>, but I don't understand why <code>tlEntries</code> is being "optimized away".</p>