diff --git a/src/main/java/com/eprosima/fastdds/idl/grammar/Context.java b/src/main/java/com/eprosima/fastdds/idl/grammar/Context.java
index bfa2a3af..347508e8 100644
--- a/src/main/java/com/eprosima/fastdds/idl/grammar/Context.java
+++ b/src/main/java/com/eprosima/fastdds/idl/grammar/Context.java
@@ -682,11 +682,11 @@ public AnnotationDeclaration getAnnotationDeclaration(
     {
         if (isInScopedFile())
         {
-            if (name.equals("optional"))
+            if (name.equals(Annotation.optional_str))
             {
                 there_is_at_least_one_optional_annotation = true;
             }
-            else if (name.equals("external"))
+            else if (name.equals(Annotation.external_str))
             {
                 there_is_at_least_one_external_annotation = true;
             }
diff --git a/thirdparty/idl-parser b/thirdparty/idl-parser
index 8f1ce907..6928bd3d 160000
--- a/thirdparty/idl-parser
+++ b/thirdparty/idl-parser
@@ -1 +1 @@
-Subproject commit 8f1ce9078238272be9f242f42e8a48af14aaa481
+Subproject commit 6928bd3d94930728c7553855a4779a1f55ce3f21