Description:
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var_export makes -1 in key of array 4294967295


i have to set version to irrelevant, but i do not know whether it is indeed irrelevant, i think i cannot upgrade. php version is 5.2.10.dfsg.1-2ubuntu6.3

Test script:
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$a=array('-1'=>100);

var_export($a);

echo '<br>';

print_r ($a);
echo '<br>';

var_dump($a);

Expected result:
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it should return '-1' or -1 in place of the key

Actual result:
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it returns 4294967295 (instead of -1)