Dear all, The following compiles with ghc 7.6 but fails with ghc 7.8: ----- {-# LANGUAGE TypeFamilies #-} {-# LANGUAGE FlexibleInstances #-} {-# LANGUAGE MultiParamTypeClasses #-} module Test where class M t s where type T t s data I t = I t instance M t t where type (T t t) = () instance M t (I t) where type (T t (I t)) = () ----- The error I get with ghc 7.8.3 and 7.8.4 is: Test.hs:12:10: Conflicting family instance declarations: T t t -- Defined at Test.hs:12:10 T t (I t) -- Defined at Test.hs:15:10 I am curious if this change is an improvement or a bug. I would be grateful for help as this issue affects a fairly large library I develop. Best regards, Michal -- |-| Dr. Michal Konecny, Computer Science, Aston University |-| Room MB212D | Tel +44 121 204 3462 | Fax +44 121 204 3681 |-| http://duck.aston.ac.uk/konecnym |-| OpenPGP key http://duck.aston.ac.uk/konecnym/ki.aston