diff --git a/rules-tests/Php85/Rector/ArrayDimFetch/ArrayFirstLastRector/Fixture/skip_as_nested_assign.php.inc b/rules-tests/Php85/Rector/ArrayDimFetch/ArrayFirstLastRector/Fixture/skip_as_nested_assign.php.inc
new file mode 100644
index 00000000000..2c5efa8170a
--- /dev/null
+++ b/rules-tests/Php85/Rector/ArrayDimFetch/ArrayFirstLastRector/Fixture/skip_as_nested_assign.php.inc
@@ -0,0 +1,13 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Rector\Tests\Php85\Rector\ArrayDimFetch\ArrayFirstLastRector\Fixture;
+
+final class SkipAsNestedAssign
+{
+    public function run(array $result, $lastInsertedId)
+    {
+        $result[\array_key_last($result)]['id'] = $lastInsertedId;
+    }
+}
diff --git a/rules-tests/Php85/Rector/ArrayDimFetch/ArrayFirstLastRector/Fixture/skip_as_nested_assign_op.php.inc b/rules-tests/Php85/Rector/ArrayDimFetch/ArrayFirstLastRector/Fixture/skip_as_nested_assign_op.php.inc
new file mode 100644
index 00000000000..cd272c7ce13
--- /dev/null
+++ b/rules-tests/Php85/Rector/ArrayDimFetch/ArrayFirstLastRector/Fixture/skip_as_nested_assign_op.php.inc
@@ -0,0 +1,13 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Rector\Tests\Php85\Rector\ArrayDimFetch\ArrayFirstLastRector\Fixture;
+
+final class SkipAsNestedAssignOp
+{
+    public function run(array $result, $lastInsertedId)
+    {
+        $result[\array_key_last($result)][0] += $lastInsertedId;
+    }
+}
diff --git a/src/PhpParser/NodeVisitor/AssignedToNodeVisitor.php b/src/PhpParser/NodeVisitor/AssignedToNodeVisitor.php
index 45347398457..55cd002673c 100644
--- a/src/PhpParser/NodeVisitor/AssignedToNodeVisitor.php
+++ b/src/PhpParser/NodeVisitor/AssignedToNodeVisitor.php
@@ -6,6 +6,8 @@
 
 use PhpParser\Node;
 use PhpParser\Node\ArrayItem;
+use PhpParser\Node\Expr;
+use PhpParser\Node\Expr\ArrayDimFetch;
 use PhpParser\Node\Expr\Assign;
 use PhpParser\Node\Expr\AssignOp;
 use PhpParser\Node\Expr\AssignRef;
@@ -22,7 +24,7 @@ final class AssignedToNodeVisitor extends NodeVisitorAbstract implements Decorat
     public function enterNode(Node $node): ?Node
     {
         if ($node instanceof AssignOp) {
-            $node->var->setAttribute(AttributeKey::IS_ASSIGN_OP_VAR, true);
+            $this->markAssignOpVar($node->var);
             return null;
         }
 
@@ -54,4 +56,19 @@ public function enterNode(Node $node): ?Node
 
         return null;
     }
+
+    /**
+     * Marks the whole dim fetch chain, not just the outermost node: $array[$key][0] += 1 writes
+     * to $array[$key] as well, so a rule that rewrites the inner fetch would change a write
+     * into a read of a temporary value.
+     */
+    private function markAssignOpVar(Expr $expr): void
+    {
+        $expr->setAttribute(AttributeKey::IS_ASSIGN_OP_VAR, true);
+
+        while ($expr instanceof ArrayDimFetch) {
+            $expr = $expr->var;
+            $expr->setAttribute(AttributeKey::IS_ASSIGN_OP_VAR, true);
+        }
+    }
 }