Wibble

compiler/GHC/Tc/Utils/Unify.hs

@@ -2580,7 +2580,7 @@ simpleUnifyCheck fam_ok lhs_tv rhs
                           go w && go a && go r
     go (TyConApp tc tys)
       | lhs_tv_is_concrete, not (isConcreteTyCon tc) = False
-      | isTypeFamilyTyCon, not fam_ok                = False
+      | not fam_ok, isTypeFamilyTyCon tc             = False
       | otherwise                                    = all go tys
     go (AppTy t1 t2)    = go t1 && go t2
     go (ForAllTy {})    = False