Question

In my application, there is this line of code causing trouble:

public class DisplayListing<R extends Listing<R, L>, L extends Listing<R, L>.Loader> extends SherlockListFragment { ... }

Working with Eclipse everything behaves fine. But after switching to IntelliJ IDEA errors are popping up:

No enclosing instance of type ‘com.app.Listing’ is in scope.

This error message refers to the part Listing<R, L>.Loader (Loader is a non-static class).

When I go to IntelliJ’s preferences and change the compiler from Javac to Eclipse I’m back to business: the application will successfully compile and run again.

But the red mark indicating an error will stay (and I would like to get rid of that). So I’m wondering if I’m actually doing something wrong and my generic arguments should be fixed or if it is okay to rely on the Eclipse compiler and ignore the error?

Answer 1

This is a legitimate bug, and it can be reproduced without any complex generics:

public class Foo<T extends Bar.Baz> {}

class Bar {
    class Baz {}
}

It appears that the IntelliJ parser (not its compiler, which is either javac or ecj) is mistaking the extends Bar.Baz to be part of the declaration of Foo, not T. In other words, it’s the same error that you (correctly) get when you do this:

public class Foo extends Bar.Baz {}

This is IDEA Issue #94011. You can upvote that issue to give it greater notice.