Hole in GNU GPL?
http://slashdot.org/article.pl?sid=00/01/17/172203&mode=nested&tid=117

Intentional programming.
http://www.research.microsoft.com/scripts/pubs/view.asp?TR_ID=MSR-TR-95-52
http://www.research.microsoft.com/scripts/pubs/view.asp?PubID=229

See :
http://gcc.gnu.org/ml/gcc/2000-11/msg00790.html
http://eidola.org/references.shtml