X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Ftypes%2FType.lhs;h=aa3cd077b05898deac0bfe17e3f09ef7cbc35121;hb=e34157d4abd4b82d9b5c32035946edcd22c235b6;hp=c736bdc1f4a51fe8f264e6123e997ff61656a8ab;hpb=17b297d97d327620ed6bfab942f8992b2446f1bf;p=ghc-hetmet.git

diff --git a/compiler/types/Type.lhs b/compiler/types/Type.lhs
index c736bdc..aa3cd07 100644
--- a/compiler/types/Type.lhs
+++ b/compiler/types/Type.lhs
@@ -6,11 +6,11 @@
 Type - public interface
 
 \begin{code}
-{-# OPTIONS_GHC -w #-}
+{-# OPTIONS -w #-}
 -- The above warning supression flag is a temporary kludge.
 -- While working on this module you are encouraged to remove it and fix
 -- any warnings in the module. See
---     http://hackage.haskell.org/trac/ghc/wiki/WorkingConventions#Warnings
+--     http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings
 -- for details
 
 module Type (
@@ -415,8 +415,14 @@ splitNewTyConApp_maybe (FunTy arg res)   = Just (funTyCon, [arg,res])
 splitNewTyConApp_maybe other	      = Nothing
 
 newTyConInstRhs :: TyCon -> [Type] -> Type
-newTyConInstRhs tycon tys =
-    let (tvs, ty) = newTyConRhs tycon in substTyWith tvs tys ty
+-- Unwrap one 'layer' of newtype
+-- Use the eta'd version if possible
+newTyConInstRhs tycon tys 
+    = ASSERT2( equalLength tvs tys1, ppr tycon $$ ppr tys $$ ppr tvs )
+      mkAppTys (substTyWith tvs tys1 ty) tys2
+  where
+    (tvs, ty)    = newTyConEtadRhs tycon
+    (tys1, tys2) = splitAtList tvs tys
 \end{code}