Description:
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If int 0 is used as an array_search or in_array needle and int 
0 is not an element in the haystack, array_search and in_array 
will return int 0 and boolean true, respectively, instead of 
boolean false as expected.

Reproduce code:
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$array = array('x', 'y', 'z');

var_dump(array_search(0, $array));
var_dump(in_array(0, $array));

Expected result:
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var_dump and in_array should have spit out boolean(false) 
since int 0 is not in array $array.

Actual result:
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int(0) bool(true)