[PHP-BUG] Bug #78407 [NEW]: Contravariant Parameters bug

From:             damian dot jozwiak dot lodz at gmail dot com
Operating system: Ubuntu 18.04
PHP version:      7.4.0beta2
Package:          PHP Language Specification
Bug Type:         Bug
Bug description:Contravariant Parameters bug

Description:
------------
When class implement an interface it is not possible to override
function parameter.
The code works fine if base function is in class

Test script:
---------------
interface Test{
    public function f1($param);
}
class inherited implements Test {
    public function f1(string $param):\DOMElement{
        return new \DOMElement($param);
    }
}
$data = new inherited();
$node = $data->f1("node");
var_dump($node->nodeName);

Expected result:
----------------
string(4) "node" 

Actual result:
--------------
Fatal error: Declaration of inherited::f1(string $param): DOMElement
must be compatible with Test::f1($param) 

-- 
Edit bug report at https://bugs.php.net/bug.php?id=78407&edit=1
-- 
Fix committed:                    https://bugs.php.net/fix.php?id=78407&r=fixed
Fixed in release:                 https://bugs.php.net/fix.php?id=78407&r=alreadyfixed
Need backtrace:                   https://bugs.php.net/fix.php?id=78407&r=needtrace
Need Reproduce Script:            https://bugs.php.net/fix.php?id=78407&r=needscript
Try newer version:                https://bugs.php.net/fix.php?id=78407&r=oldversion
Not developer issue:              https://bugs.php.net/fix.php?id=78407&r=support
Expected behavior:                https://bugs.php.net/fix.php?id=78407&r=notwrong
Not enough info:                  https://bugs.php.net/fix.php?id=78407&r=notenoughinfo
Submitted twice:                  https://bugs.php.net/fix.php?id=78407&r=submittedtwice
register_globals:                 https://bugs.php.net/fix.php?id=78407&r=globals
PHP version support discontinued: https://bugs.php.net/fix.php?id=78407&r=phptooold
Daylight Savings:                 https://bugs.php.net/fix.php?id=78407&r=dst
IIS Stability:                    https://bugs.php.net/fix.php?id=78407&r=isapi
Install GNU Sed:                  https://bugs.php.net/fix.php?id=78407&r=gnused
Floating point limitations:       https://bugs.php.net/fix.php?id=78407&r=float
No Zend Extensions:               https://bugs.php.net/fix.php?id=78407&r=nozend
MySQL Configuration Error:        https://bugs.php.net/fix.php?id=78407&r=mysqlcfg