I am working on improving new comparison primops and implementing Geoffrey's proposal [1]. I renamed GHC.Prim to GHC.Prim.BuiltIn and GHC.PrimWrappers (in ghc-prim library) to GHC.Prim. I can build the compiler and testsuite passes succesfully, but ./validate fails with 'haddock panic' when building documentation for ghc-prim library: Haddock coverage: 100% ( 1 / 1) in 'GHC.IntWord64' haddock: internal error: haddock: panic! (the 'impossible' happened) (GHC version 7.7.20130823 for x86_64-unknown-linux): Static flags have not been initialised! Please call GHC.newSession or GHC.parseStaticFlags early enough. Have any of you ever broke haddock in a similar way? Looks as if GHC session was not initialized properly, but I have no idea how could I have triggered such a behaviour. Janek [1] - http://www.haskell.org/pipermail/ghc-devs/2013-August/002072.html