Idriss has encountered a bug in JastAdd, see attachment. He gets a compilation error when trying to define a collection attribute on an interface. But if he changes the file name from s.jrag to r.jrag, the compilation gets through. He has narrowed down the problem to a very small example.
I tried it on my computer and I got the same compilation error for s.jrag, and also got the error if I changed the filename to r.jrag. But if I changed the filename to z.jrag, the compilation error disappeared.
I guess this problem is related to side effects in aspect weaving as discussed in https://bitbucket.org/jastadd/jastadd2/issues/268/remove-side-effects-in-aspect-weaving