Further to my previous comments about ghc-2.04 and Happy output, I can report that having mangled happy-0.9 output to work with 1.4ish arrays, the situation is more dire yet. For the same happy input program as previously reported, ghc _really_ struggles to compile the -a output -- with a 100Mb heap under Solaris, it doesn't get past the DeSugar phase. (I'd tell you what happens with a 120Mb heap, but it's still trashing one of our Ultras quite senseless.) Must be a space-leak, surely? Cheers, Alex.