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 (
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}