Description:
------------
1. Passing arguments using the ... operator ignores requirements as to which arguments must be passed by reference.

2. Prevents warnings from subsequent calls that previously threw it (maybe it is some inner cache issue).

https://3v4l.org/ksVmp

Actually, there is a different behavior for 7.0, 7.3+, and 7.1 - 7.2.


Test script:
---------------
<?php

$foo = function (int &$bar) { $bar++; };
$baz = 0;
$args = [$baz];

call_user_func_array($foo, $args);
echo $args[0];

call_user_func_array($foo, $args);
echo $args[0];

$foo(...$args);
echo $args[0];

call_user_func_array($foo, $args);
echo $args[0];

call_user_func_array($foo, $args);
echo $args[0];

Expected result:
----------------
Warning: Parameter 1 to {closure}() expected to be a reference, value given in /in/ksVmp on line 7
0
Warning: Parameter 1 to {closure}() expected to be a reference, value given in /in/ksVmp on line 10
0
Warning: Parameter 1 to {closure}() expected to be a reference, value given in /in/ksVmp on line 13
0
Warning: Parameter 1 to {closure}() expected to be a reference, value given in /in/ksVmp on line 16
0
Warning: Parameter 1 to {closure}() expected to be a reference, value given in /in/ksVmp on line 19
0

Actual result:
--------------
Warning: Parameter 1 to {closure}() expected to be a reference, value given in /in/ksVmp on line 7
0
Warning: Parameter 1 to {closure}() expected to be a reference, value given in /in/ksVmp on line 10
0123