Problem with POST data types

After update from 4.4.7 to 4.5 i got erros when i POSST data via AJAX, and validate data with custom function like



public function validateRange (int $number): bool {
return ($number > 5 && $number < 10);
}

before it worked properly i got by POST variable number

["number "]=>
string(1) "7"


but now i got " Argument #1 ($number) must be of type int, string given"

How prevent it, instead converting all data before validation?
is bug of 4.5 version CI?

Or is it possible auto convert POST data to exact type of data?