Description:
------------
PHP 7.3.5 throws a "Fatal error: Uncaught Error: Unsupported operand types ..." when opcache is enabled in php.ini on Ubuntu Linux 16.04, 18.04, 19.04.

Notes:
- The error is only thrown on a first http request after server started or restarted (the following requests work as expected). 
- The error is thrown on Apache web server as well as on a PHP built-in web server.
- The error is not present on Windows.

Workaround:
Set opcache.optimization_level=0x7FFFBFDF in php.ini (instead of the default value 0x7FFFBFFF).

Test script:
---------------
index.php:
<?php require_once 'simple.php'; ?>

simple.php:
<?php

$x = 1;

function f() {
	global $x;

	$a = ['b' => [$x], 'c' => [$x]];
	$d = $a['b'] + $a['c'];
}


Expected result:
----------------
Empty output, no PHP errors.

Actual result:
--------------
Fatal error: Uncaught Error: Unsupported operand types in /var/www/html/index.php:1 Stack trace: #0 {main} thrown in /var/www/html/index.php on line 1