I cannot reproduce this error yet, but its causing me huge trouble in release and package scenarios. I have a packaged class which implements an Abstract superclass. Sometimes when I refactor this super class and its implementors I get trapped by Compiler errors that show code lines that do NOT exist in the class anymore.
It looks like Salesforce is keeping the latest compilable version in a cache and ignore the changes I made.
Did you see the same and found any workaround?! Normally I delete and undelete the problematic class. But I cannot do this as I am working in a patch org were nothing can be deleted.
Is this a bug introduced by Summer '13?