GUID验证RegEx失败换行符

Question

我正在尝试使用以下代码行验证PHP中的GUID。

$case_number = "088169ed-7a9d-4f78-b999-170971247642\n";
$GUID_validation_RegEx = '/^[A-Fa-f\d]{8}-[A-Fa-f\d]{4}-[A-Fa-f\d]{4}-[A-Fa-f\d]{4}-[A-Fa-f\d]{12}$/';
print(preg_match($GUID_validation_RegEx, $case_number));

它返回1 (true)

我已将问题缩小到以下范围...

^[A-Fa-f\d]{8}-[A-Fa-f\d]{4}-[A-Fa-f\d]{4}-[A-Fa-f\d]{4}-[A-Fa-f\d]{12}$

                                            ^^^ these A-F (if I remove them the new line does not match)

为什么会这样，我该如何解决？