I accidentally created a class that extended itself, so obviously this is the simplest case of the above.
When Eclipse auto-builds the project, the compiler ends with a stack overflow error. The only problem that appeared in Eclipse was the stack overflow issue.
I've been trying to discover what was causing this, and finally on a different machine, the compiler was able to report the error 'class blah has an inheritance cycle. It cannot extend itself' (not an exact quote, as I don't have the error anymore, but it was something like that), so I was finally able to see the error.