I'm currently having a problem with compiling modules. I have two files Data.hs and Class.hs (Class depends on Data). When I compile Class.hs (ghc --make Class.hs) the ghc does what it should do. When I now make a change to Class.hs (add a newline to the end of the file for example) and try to run ghc --make Class.hs again the ghc gets stuck on recompiling Class.hs. I think this is a bug in the GHC, can anybody confirm this? (it only occurs in GHC-7.6.1 both x86 and i386 versions, GHC-7.4 doesn't have this problem, I only tried it on OS X). Or did I miss something else? It doesn't happen when the Exp data type in Data.hs only has one constructor. Contents of the two module involved: Class.hs

{-# LANGUAGE GADTs, TypeFamilies #-} module Class where

import Data

data Q a where Q :: QA a => Exp (F a) -> Q a

class QA a where type F a

Data.hs

{-# LANGUAGE GADTs #-} module Data where

data Exp a where LamE :: (Exp a -> Exp b) -> Exp (Exp a -> Exp b) VarE :: Integer -> Exp a

Cheers, Jeroen