diff --git a/rules/RequireClosureReturnTypeRule.php b/rules/RequireClosureReturnTypeRule.php
index 5a9975e..ace2ca5 100644
--- a/rules/RequireClosureReturnTypeRule.php
+++ b/rules/RequireClosureReturnTypeRule.php
@@ -23,6 +23,9 @@ public function getNodeType(): string
         return Node\Expr::class;
     }
 
+    /**
+     * @return list<\PHPStan\Rules\IdentifierRuleError>
+     */
     public function processNode(Node $node, Scope $scope): array
     {
         if (!$node instanceof Node\Expr\Closure && !$node instanceof Node\Expr\ArrowFunction) {
@@ -35,7 +38,7 @@ public function processNode(Node $node, Scope $scope): array
             return [
                 RuleErrorBuilder::message(
                     sprintf('%s is missing a return type declaration', $nodeType)
-                )->build(),
+                )->identifier('Ibexa.requireClosureReturnType')->build(),
             ];
         }