Remove old, redundant note

[ghc-hetmet.git] / compiler / typecheck / TcDeriv.lhs

diff --git a/compiler/typecheck/TcDeriv.lhs b/compiler/typecheck/TcDeriv.lhs
index 4aa2089..3cfaaa9 100644 (file)
--- a/compiler/typecheck/TcDeriv.lhs
+++ b/compiler/typecheck/TcDeriv.lhs
@@ -362,8 +362,8 @@ renameDeriv is_boot gen_binds insts
              ; let binds' = VanillaInst rn_binds [] standalone_deriv
              ; return (InstInfo { iSpec = inst, iBinds = binds' }, fvs) }
        where
-         (tyvars,_,clas,_) = instanceHead inst
-         clas_nm           = className clas
+         (tyvars,_, clas,_) = instanceHead inst
+         clas_nm            = className clas
 
 -----------------------------------------
 mkGenericBinds :: Bool -> [LTyClDecl Name] -> TcM (LHsBinds RdrName)
@@ -1147,9 +1147,9 @@ mkNewTypeEqn orig dflags tvs
                                         
        cant_derive_err
           = vcat [ ptext (sLit "even with cunning newtype deriving:")
-                 , if arity_ok then empty else arity_msg
-                 , if eta_ok then empty else eta_msg
-                 , if ats_ok then empty else ats_msg ]
+                 , ppUnless arity_ok arity_msg
+                 , ppUnless eta_ok eta_msg
+                 , ppUnless ats_ok ats_msg ]
         arity_msg = quotes (ppr (mkClassPred cls cls_tys)) <+> ptext (sLit "does not have arity 1")
        eta_msg   = ptext (sLit "cannot eta-reduce the representation type enough")
        ats_msg   = ptext (sLit "the class has associated types")
@@ -1387,6 +1387,7 @@ genInst standalone_deriv oflag spec
 -- When dealing with the deriving clause
 --    co1 : N [(b,b)] ~ R1:N (b,b)
 --    co2 : R1:N (b,b) ~ Tree (b,b)
+--    co  : N [(b,b)] ~ Tree (b,b)
 
 genDerivBinds :: SrcSpan -> FixityEnv -> Class -> TyCon -> (LHsBinds RdrName, DerivAuxBinds)
 genDerivBinds loc fix_env clas tycon