[DeadCode] Handle crash on multi elseif on RemoveDeadIfBlockRector (#7946)

Author: samsonasik

rules-tests/DeadCode/Rector/If_/RemoveDeadIfBlockRector/Fixture/multi_elseif_with_binaryop.php.inc

@@ -0,0 +1,33 @@
+<?php
+
+namespace Rector\Tests\DeadCode\Rector\If_\RemoveDeadIfBlockRector\Fixture;
+
+class MultiElseIfWithBinaryOp
+{
+    public function run($value, $flag)
+    {
+        if ($flag) {
+        } elseif ($value === 2) {
+        } elseif ($value === 3 || $value === 4) {
+            echo "matched";
+        }
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\DeadCode\Rector\If_\RemoveDeadIfBlockRector\Fixture;
+
+class MultiElseIfWithBinaryOp
+{
+    public function run($value, $flag)
+    {
+        if (!$flag && ($value === 3 || $value === 4)) {
+            echo "matched";
+        }
+    }
+}
+
+?>

rules/DeadCode/Rector/If_/RemoveDeadIfBlockRector.php

@@ -102,12 +102,12 @@ public function refactor(Node $node): int|null|If_
         }
 
         foreach ($node->elseifs as $elseif) {
-            $keep_elseifs = array_filter(
+            $keep_elseifs = array_values(array_filter(
                 $node->elseifs,
                 fn (ElseIf_ $elseif): bool => $elseif->stmts !== [] || $this->sideEffectNodeDetector->detect(
                     $elseif->cond
                 )
-            );
+            ));
             if (count($node->elseifs) !== count($keep_elseifs)) {
                 $node->elseifs = $keep_elseifs;
                 return $this->refactor($node) ?? $node;