I have a trait Auditable with a method void publish() that is "implemented" by an abstract class. The concrete subclass has an error marker saying

Can't have an abstract method in a non-abstract class: [...] or the method 'void publish()' must be implemented.

This looks to be a bug with the Eclipse index where it confuses the fact that traits look like Java interfaces (no implementation) with their having the code added at compile-time. The classes actually compile fine, and I don't get an adornment in Package Explorer.