Description:
------------
Since version of PHP 7.2.0 (stable) and 7.2.1 RC1 count() will raise a warning if argument is either null or empty string.

It is hard to file this either as a bug, or documentation problem, because as stated in the manual (here: php.net/manual/en/function.count.php), examples are now obsolete / wrong.

Additionally, in the same page in Changelog it is stated this, which adds even more to the confusion:

Changelog
Version	Description
7.2.0	count() will not yield a warning on invalid countable types passed to the array_or_countable parameter.

Test script:
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$s = '';
echo count($s); // returns 1 with a warning

$n = null;
echo count($n); // returns 0 with a warning

$f = false;
echo count($f); // returns 1 with a warning

Expected result:
----------------
No warnings issued, or update documentation to include warnings issued.