Migrating form Eclipse generates Error: Object cannot be converted to Enum<?>

I have just imported an Android project from Eclipse and IntelliJ generates the following error:
error: incompatible types: Object cannot be converted to Enum<?>

The following code generates the error:

EnumSet<?>[] cars = new EnumSet[8];
// cars is filled with Enums

for (Enum<?> n : cars[0]) desc += n.toString();

The error is removed if the redundant cast is included:

for (Enum<?> n : (EnumSet<?>) cars[0]) desc += n.toString();

Any suggestions or is this an error with the compiler? I am a new user of IntelliJ and Android Studio.

Thanks