src/jdk.compiler/share/classes/com/sun/tools/javac/jvm/ClassWriter.java

@@ -1038,11 +1038,18 @@
 
     /** Enter an inner class into the `innerClasses' set/queue.
      */
     void enterInner(ClassSymbol c) {
         if (c.type.isCompound()) {
-            throw new AssertionError("Unexpected intersection type: " + c.type);
+            if (c.type.isIntersection()) {
+                types.directSupertypes(c.type).stream()
+                    .map(t -> (ClassSymbol) t.tsym)
+                    .forEach(this::enterInner);
+                return;
+            } else {
+                throw new AssertionError("Unexpected compound type: " + c.type);
+            }
         }
         try {
             c.complete();
         } catch (CompletionFailure ex) {
             System.err.println("error: " + c + ": " + ex.getMessage());