Since I'm not sure that this was written seriously, I'll point to anecdotal evidence of cfront, Stroustrup's C++ compiler, being the buggiest C++ compiler ever written. (Here's a bunch of bugs found by modern static analysis tools - http://www.i-programmer.info/programming/cc/9212-finding-bug... - but unfortunately I can't find the Usenet old posts telling that cfront was the buggiest C++ compiler of its time, and that early g++ was the next buggiest. The Unix-Haters Handbook has evidence from James Roskind who tried to make a yacc grammar for C++ - to a first approximation, an impossible thing to do due to a few goofy design decisions in the C++ grammar - and who said that every time when he tried to feed cfront input that would enlighten him with respect to some dark corner of the grammar, cfront crashed.)