Description:
------------
Serving the test script via php7.2-fpm results in php worker process always crashing. Removing the @ fixes the problem, but logs undesided warnings. The actual code being used is rather complex, the test script has just the minimum statements required to reproduce the crash.

Note that PHP <= 7.1 handles the test code correctly - it does not crash.

Test script:
---------------
<?php
error_reporting(E_ALL|E_STRICT);

function test() {
  $a = array("a","b","c","b");
  $b = array();
  foreach ($a as $c)
    @$b[$c]++; // the @ is required to crash PHP 7.2.0
  var_dump($b);
}

test();