UNDOCUMENTED BEHAVIOR:
list($a,$b,$c) = null;
in fact works like:
$a = null; $b = null; $c = null;
...So correspondingly:
list($rows[]) = null;
Will increment count($rows), just as if you had executed $rows[] = null;
Watch out for this (for example) when retrieving entire tables from a database, e.g.
while (list($rows[]) = $mysqlresult->fetch_row());
This will leave an extra 'null' entry as the last element of $rows.