On Thu, Feb 05, 2009 at 10:41:20AM +0100, Wolfgang Jeltsch wrote: > type-level built fine with GHC 6.8 but failed to build with GHC > 6.10. The last line of the build log is this: > > > haddock: internal Haddock or GHC error: Maybe.fromJust: Nothing Yes, haddock 2.4.1 (the most recent release) bombs on Data.TypeLevel.Num.Aliases.