Description:
------------
The array_combine function skips keys of type other than int or string while operator [] allows one to add also other types (like null,boolean, float). Note, that array_combine converts string keys in exactly the same way as the operator [] does (i.e. "10" -> 10 etc.).

IMHO array_combine should not skip keys with other types than string or int but convert them to a string or an int.
Thus array_combine should behave like [] operator.
Moreover, the PHP_Compat package does it so but there is another bug there: if illegal key is found (e.g. an array) a warning is reported instead of skipping such key (@ is missing there).


Reproduce code:
---------------
$a = array("0",0,"-10",-10,null,5.4,array(1,2,3),false);
$b = array(1,2,3,4,5,6,7,8);
var_dump(array_combine($a,$b));


Expected result:
----------------
array(4) {
  [0]=>
  int(8)
  [-10]=>
  int(4)
  [""]=>
  int(5)
  [5]=>
  int(6)
}


Actual result:
--------------
array(2) {
  [0]=>
  int(2)
  [-10]=>
  int(4)
}