Description:
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使用taint后，array_walk_recursive结果有误


Test script:
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$a = array();
$a[0] = "tainted string" . "<>";
taint($a[0]); 

array_walk_recursive($a, create_function('&$item', '$item = htmlspecialchars($item);'));

echo $a[0];

Expected result:
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tainted string&lt;&gt;

Actual result:
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Warning: main(): Attempt to echo a string that might be tainted in /usr/local/taint-1.0.0/tests/012.php on line 8
tainted string<> （尖括号没有转义，而且输出了warning）