Unresolvable loop causes incorrect behavior of `AddDefaultValueForUndefinedVariableRector`

[jackbentley]

Bug Report

Subject	Details
Rector version	last dev-main
Installed as	composer dependency

Minimal PHP Code Causing Issue

See https://getrector.com/demo/e1b4cf4e-c34f-466d-ac1a-4ecdbffca61c

<?php

final class DemoFile
{   
    public function run(Item $yes)
    {
        while (true !== false) {
        }
        
        $a = [];
        
        if ($b = $yes) {
            $a[] = 'test';
        }
        
        return $a;
    }
}

More real-world example:

See https://getrector.com/demo/c74cd93b-9c55-41d6-b831-24f952405737

<?php

final class Item
{
    private $parent;
    
    /**
     * @return Item
     */
    public function getParent()
    {
        return $this->parent;
    }    
}

final class DemoFile
{
    private function create()
    {
        return [];
    }
    
    public function run(Item $yes)
    {
        while (($yes = $yes->getParent()) !== null) {
        }
        
        $a = $this->create();
        
        if ($b = $yes) {
            $a[] = 'test';
        }
        
        return $a;
    }
}

Responsible rules

• AddDefaultValueForUndefinedVariableRector

Expected Behavior

Rector shouldn't "fix" this. The variable is always set. Removing the while makes Rector think the code is correct.

[TomasVotruba]

Thank you for your report and demo link!

We'll need a failing test case in a pull-request, so we have it covered in Rector.
You can click "Create a Test" button at demo page.