[DeadCode] Skip used from property fetch reference on loop on RemoveUnusedVariableAssignRector (#7635)

* [DeadCode] Skip used from property fetch reference on loop on RemoveUnusedVariableAssignRector

* fix phpstan

Author: samsonasik

rules-tests/DeadCode/Rector/Assign/RemoveUnusedVariableAssignRector/Fixture/skip_used_from_property_fetch_reference.php.inc

@@ -0,0 +1,13 @@
+<?php
+
+namespace Rector\Tests\DeadCode\Rector\Assign\RemoveUnusedVariableAssignRector\Fixture;
+
+function SkipUsedFromPropertyFetchReference(\stdClass $target, array $path, mixed $value): void {
+    $current = $target;
+    foreach ($path as $key) {
+      $current = &$current->{$key};
+    }
+    $current = $value;
+}
+
+?>

rules/DeadCode/Rector/Assign/RemoveUnusedVariableAssignRector.php

@@ -19,6 +19,7 @@
 use PhpParser\Node\Stmt\Expression;
 use PhpParser\Node\Stmt\Function_;
 use PhpParser\NodeVisitor;
+use Rector\Contract\PhpParser\Node\StmtsAwareInterface;
 use Rector\DeadCode\SideEffect\SideEffectNodeDetector;
 use Rector\NodeAnalyzer\VariableAnalyzer;
 use Rector\NodeManipulator\StmtsManipulator;
@@ -158,6 +159,27 @@ private function shouldSkip(array $stmts): bool
         });
     }
 
+    /**
+     * @param string[] $refVariableNames
+     */
+    private function collectAssignRefVariableNames(Stmt $stmt, array &$refVariableNames): void
+    {
+        if (! $stmt instanceof StmtsAwareInterface) {
+            return;
+        }
+
+        $this->traverseNodesWithCallable(
+            $stmt,
+            function (Node $subNode) use (&$refVariableNames): Node {
+                if ($subNode instanceof AssignRef && $subNode->var instanceof Variable) {
+                    $refVariableNames[] = (string) $this->getName($subNode->var);
+                }
+
+                return $subNode;
+            }
+        );
+    }
+
     /**
      * @param array<int, Stmt> $stmts
      * @return array<int, string>
@@ -169,6 +191,7 @@ private function resolvedAssignedVariablesByStmtPosition(array $stmts): array
 
         foreach ($stmts as $key => $stmt) {
             if (! $stmt instanceof Expression) {
+                $this->collectAssignRefVariableNames($stmt, $refVariableNames);
                 continue;
             }