Hi Daniel, > IMHO, these lines also infringe upon the above mentioned rule or did I miss > something important? The compiler *CAN* warn about those kinds of infringements. The compiler does *NOT* *HAVE* to warn about those kinds of infringements. GCC 3.3.5 detects the simple case. It does not (I presume) detect the indirect case that you provided. In some situations it may be very hard to detect the indirect case during compile time, and it could be very expensive to check for it at run time. HTH, --Eljay