I entered the code below in NB 6.0 B2 and then tried to refactor-rename the 'enum' identifier to 'iter'.

The rename failed (see Issue 121086) and the following appeared in log file.

-----
/*
 * Demonstrate CasualDiff Illegal values bug.
 */

/**
 * @author Joseph Bowbeer
 */
public class CasualDiffBug {
    public static void main(String[] args) {
        Object enum;
    }
}
-----
INFO [org.netbeans.modules.java.source.save.CasualDiff]: Illegal values: from = 184; to = 183.
Please, attach your messages.log to new issue!


Btw, the rename action changed the affected line to:

        Object ite    }

Using a different illegal identifier, such as 'new', does not log a message but fails in a different way: it renames the
'main' method instead of the Object identifier.