diff --git a/packages/CodeQuality/src/Rector/Foreach_/ForeachItemsAssignToEmptyArrayToAssignRector.php b/packages/CodeQuality/src/Rector/Foreach_/ForeachItemsAssignToEmptyArrayToAssignRector.php
index 2e4501728eab..d2e6f9323fb4 100644
--- a/packages/CodeQuality/src/Rector/Foreach_/ForeachItemsAssignToEmptyArrayToAssignRector.php
+++ b/packages/CodeQuality/src/Rector/Foreach_/ForeachItemsAssignToEmptyArrayToAssignRector.php
@@ -113,6 +113,10 @@ private function matchAssignItemsOnlyForeachArrayVariable(Foreach_ $foreach): ?E
             return null;
         }
 
+        if ($onlyStatement->var->dim !== null) {
+            return null;
+        }
+
         if (! $this->areNodesEqual($foreach->valueVar, $onlyStatement->expr)) {
             return null;
         }
diff --git a/packages/CodeQuality/tests/Rector/Foreach_/ForeachItemsAssignToEmptyArrayToAssignRector/Fixture/skip_non_empty_dim_key_1.php.inc b/packages/CodeQuality/tests/Rector/Foreach_/ForeachItemsAssignToEmptyArrayToAssignRector/Fixture/skip_non_empty_dim_key_1.php.inc
new file mode 100644
index 000000000000..069757509c93
--- /dev/null
+++ b/packages/CodeQuality/tests/Rector/Foreach_/ForeachItemsAssignToEmptyArrayToAssignRector/Fixture/skip_non_empty_dim_key_1.php.inc
@@ -0,0 +1,16 @@
+<?php
+
+namespace Rector\CodeQuality\Tests\Rector\Foreach_\ForeachItemsAssignToEmptyArrayToAssignRector\Fixture;
+
+class SkipNonEmptyDimKey1
+{
+    public function indexBy(array $array, callable $key): array
+    {
+        $indexed = [];
+        foreach ($array as $item) {
+            $indexed[$key($item)] = $item;
+        }
+
+        return $indexed;
+    }
+}
diff --git a/packages/CodeQuality/tests/Rector/Foreach_/ForeachItemsAssignToEmptyArrayToAssignRector/Fixture/skip_non_empty_dim_key_2.php.inc b/packages/CodeQuality/tests/Rector/Foreach_/ForeachItemsAssignToEmptyArrayToAssignRector/Fixture/skip_non_empty_dim_key_2.php.inc
new file mode 100644
index 000000000000..e05ae73a2607
--- /dev/null
+++ b/packages/CodeQuality/tests/Rector/Foreach_/ForeachItemsAssignToEmptyArrayToAssignRector/Fixture/skip_non_empty_dim_key_2.php.inc
@@ -0,0 +1,27 @@
+<?php
+
+namespace Rector\CodeQuality\Tests\Rector\Foreach_\ForeachItemsAssignToEmptyArrayToAssignRector\Fixture;
+
+class SkipNonEmptyDimKey2
+{
+    public function mapWithKeys(array $array, callable $fn): array
+    {
+        $result = [];
+        foreach ($array as $key => $value) {
+            foreach (self::assertIterable($fn($value, $key)) as $mapKey => $mapValue) {
+                $result[$mapKey] = $mapValue;
+            }
+        }
+
+        return $result;
+    }
+
+    public static function assertIterable($traversable)
+    {
+        if (is_iterable($traversable)) {
+            return $traversable;
+        }
+
+        throw new \UnexpectedValueException('Traversable expected');
+    }
+}