Description:
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An SplFileObject is clonable according to reflection, but errs on attempting to clone.


Related bug report: 53967

Test script:
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$x=new SplFileObject("tests.php");
$r=new ReflectionObject($x);
var_dump($r->isCloneable());

$y=clone $x; //fatal error

Expected result:
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At worst, such things should issue a warning. This clone might happen as part of more general clone that involves many objects and arrays, and with a fatal error there is no way to recover from this, but it is not a big deal and should be recoverable.

Changing it to E_WARNING is a possible scenario, or throwing appropriate exceptions on PHP 7.

Also, note in the documentation that reflection stats are not accurate regarding core classes and functions.

Actual result:
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make cloneable, return false, or E_WARNING