diff --git a/Validation/ValidatorAbstract.php b/Validation/ValidatorAbstract.php
index 4bee38dde..4fb7824d0 100644
--- a/Validation/ValidatorAbstract.php
+++ b/Validation/ValidatorAbstract.php
@@ -48,7 +48,7 @@ abstract class ValidatorAbstract
     /**
      * {@inheritdoc}
      */
-    public static function getMessage()
+    public static function getMessage() : string
     {
         return self::$msg;
     }