the snippet showing the bug follows:

    public enum SomeEnum {
        ONE, TWO
    }

    public boolean method () {
        SomeEnum someEnum = SomeEnum.ONE;
        boolean flag = true;
        if ( 1 > 0 ) {
            switch ( someEnum ) {
                case ONE:
                    flag = false; // UnusedAssignment raised here
                    break;
                case TWO:
                    throw new RuntimeException();
            }
        }
        return flag;
    }

As you can easily see, the flag will be set to false by the statement, proving that it *isn't* unused, and then returned. Actually, the unused assignment is the initializer, but it requires the "1>0" condition to be changed to simply "true" to get the proper warning on it. Also, even then the 'flag = false' is marked as unused (while it's obviously used).

Note that commenting out the "if" completely makes the bug disappear, as well as commenting out the exception. I suspect the parser "sees" the exception as a terminating point and somehow "skips" the "break;" between, "seeing" the "flag=false" operation as preceding the throw (which is not the case).