Missing validation on implicit implements Stringable declaration

[the-liquid-metal]

Bug Description Missing validation on implicit implements Stringable declaration.

Eclipse environment Version: 2023-06 (4.28.0) Build id: 20230608-1333 PDT: 8.0.0.202306050832

System

• PHP Version: 8.2.7, 8.1.20, 8.0.29, 7.4.33 (via https://onlinephp.io/)

To Reproduce Steps to reproduce the behavior: copy-paste this script to the IDE

<?php
declare(strict_types=1);

namespace ns1\ns2;

use Stringable;

class Test54 implements Stringable { // OK
    public function __toString(): string {}
}

class Test54b { // this statement should trigger warning
    public function __toString(): string {}
}