Dynamic rules are not executed for nodes that are not traversed via Walk

[quasilyte]

Given this rule:

$a[count($a)];

We find only 1 issue in the code below:

  if ($tabs[count($tabs)] == "") {
    unset($tabs[count($tabs)]);
  }

This is due to the fact that unset statement handled in a special way by BlockWalker. There are other statements like this, so the issue is more general than just adding the ad-hoc solution to the unset statement handling.