Is this a bug in PHP? Running execute.php on Ubuntu with PHP 5.5.4 executes successfully, but on CentOS with same PHP version it gives Fatal error.

execute.php

<?php

// Autoloader that does not need subdirectories (because Gist does not support subdirectories).
// Same thing happens with default SPL autoloader where namespaced files are in subdirectories.
spl_autoload_register(
    function($class) {
        spl_autoload(str_replace("\\", "_", $class));
    }
);

$bar = new Some\Bar();

$foo = new Some\Foo();
$foo->bar($bar);

other_bar.php

<?php

namespace Other;

class Bar {
    public function baz() {
        echo "self: " . get_class($this) . "\n";
    }
}

some_bar.php

<?php

namespace Some;

use Other\Bar as OtherBar;

class Bar extends OtherBar {
    public function baz() {
        echo "self: " . get_class($this) . "\n";
        echo "parent: " . get_parent_class($this) . "\n";
    }
}

some_foo.php

<?php

namespace Some;

use Other\Bar;

class Foo {
    public function bar(Bar $bar) {
        $bar->baz();
    }
}

I face the same issue but in my case the opcache.enable_cli flag doesn't actually affect the problem. For now, I don't really know what causes the problem but in my machine the problem does not exist but on the server it exists. In both cases the opcache.enable_cli is disabled.

My machine (there's no problem)

PHP 7.0.2-4+deb.sury.org~trusty+1 (cli) ( NTS )
Copyright (c) 1997-2015 The PHP Group
Zend Engine v3.0.0, Copyright (c) 1998-2015 Zend Technologies
    with Zend OPcache v7.0.6-dev, Copyright (c) 1999-2015, by Zend Technologies

The server (the error gets thrown)

PHP 7.0.0 (cli) (built: Dec  9 2015 09:25:52) ( NTS )
Copyright (c) 1997-2015 The PHP Group
Zend Engine v3.0.0, Copyright (c) 1998-2015 Zend Technologies
    with Zend OPcache v7.0.6-dev, Copyright (c) 1999-2015, by Zend Technologies

excellent work.

without opcache:

https://gist.github.com/wandersonwhcr/e16e9dcfb2c54dafa2f84c145b0de983

same problem

5.6.30 - actual

5.5.30，the same issue occurs when opcache is disabled and disappears when opcache is enabled.