array_push() and array_unshift()

array_push() and array_unshift() can now also be called with a single argument:

$array = [];

array_push($array);
array_unshift($array);

var_dump($array);

Executing the code shown above will print the output shown below:

array(0) {
}

Being able to call array_push() and array_unshift() with only a single argument is useful when the spread operator ... is used as ...$values may be unpacked to an empty list in which case array_push($array, ...$values), for instance, leads to array_push() being called with only $array as argument.