--- old/src/jdk.jextract/share/classes/com/sun/tools/jextract/AsmCodeFactory.java	2018-04-02 20:55:36.000000000 -0700
+++ new/src/jdk.jextract/share/classes/com/sun/tools/jextract/AsmCodeFactory.java	2018-04-02 20:55:35.000000000 -0700
@@ -111,7 +111,9 @@
             throws IOException {
         cw.visitEnd();
         byte[] bytecodes = cw.toByteArray();
-        types.put(clsName, bytecodes);
+        if (null != types.put(clsName, bytecodes)) {
+            logger.warning("Class " + clsName + " definition is overwritten");
+        }
     }
 
     /**
@@ -234,6 +236,15 @@
     }
 
     private void createEnum(Cursor cursor) {
+        // Anonymous enum without proper name, define in global_cw
+        if (cursor.isAnonymousEnum()) {
+            logger.fine("create anonymous enum");
+            cursor.stream()
+                    .filter(cx -> cx.kind() == CursorKind.EnumConstantDecl)
+                    .forEachOrdered(cx -> addConstant(global_cw, cx));
+            return;
+        }
+
         String nativeName = Utils.getIdentifier(cursor);
         logger.fine(() -> "create enum: " + nativeName);