Thanks, Simon. I will work on building a smaller complete test case that reproduces the issue, and I could have done a better job of at least pointing out the relevant code for you. Sorry about that. I'm definitely not building my own IIModule. The use of the GHC API is as follows. (I'm fairly sure you can ignore doWithErrors, so I haven't included it; it just sets up some log actions and exception and signal handlers, runs its argument in the Ghc monad, and converts the result from a Maybe to an Either that reports errors). doWithErrors :: GHC.Ghc (Maybe a) -> IO (Either [String] a) compile :: String -> String -> FilePath -> IO (Either [String] t) compile vname tname fn = doWithErrors $ do dflags <- GHC.getSessionDynFlags let dflags' = dflags { GHC.ghcMode = GHC.CompManager, GHC.ghcLink = GHC.LinkInMemory, GHC.hscTarget = GHC.HscAsm, GHC.optLevel = 2, GHC.safeHaskell = GHC.Sf_Safe, GHC.packageFlags = [GHC.TrustPackage "gloss", GHC.ExposePackage "gloss-web-adapters" ] } GHC.setSessionDynFlags dflags' target <- GHC.guessTarget fn Nothing GHC.setTargets [target] r <- fmap GHC.succeeded (GHC.load GHC.LoadAllTargets) case r of True -> do mods <- GHC.getModuleGraph let mainMod = GHC.ms_mod (head mods) GHC.setContext [ mainMod ] [ GHC.simpleImportDecl (GHC.mkModuleName "Graphics.Gloss"), GHC.simpleImportDecl (GHC.mkModuleName "GlossAdapters") ] v <- GHC.compileExpr $ vname ++ " :: " ++ tname return (Just (unsafeCoerce# v)) False -> return Nothing -- Chris