src/java.compiler/share/classes/javax/lang/model/util/AbstractElementVisitor6.java

@@ -137,8 +137,9 @@
      *
      * @since 9
      */
     @Override
     public R visitModule(ModuleElement e, P p) {
-        return visitUnknown(e, p);
+        // Use implementation from interface default method
+        return ElementVisitor.super.visitModule(e, p);
     }
 }