[project @ 2005-11-16 12:55:58 by simonpj]

[ghc-hetmet.git] / ghc / compiler / types / TypeRep.lhs

diff --git a/ghc/compiler/types/TypeRep.lhs b/ghc/compiler/types/TypeRep.lhs
index 4c0d01b..dc53445 100644 (file)
--- a/ghc/compiler/types/TypeRep.lhs
+++ b/ghc/compiler/types/TypeRep.lhs
@@ -152,13 +152,15 @@ data Type
        Type            -- It must be another AppTy, or TyVarTy
                        -- (or NoteTy of these)
 
-  | TyConApp           -- Application of a TyCon, including newtypes
+  | TyConApp           -- Application of a TyCon, including newtypes *and* synonyms
        TyCon           --  *Invariant* saturated appliations of FunTyCon and
                        --      synonyms have their own constructors, below.
-                       -- However, *unsaturated* type synonyms, and FunTyCons
-                       --      do appear as TyConApps.  (Unsaturated type synonyms
-                       --      can appear as the RHS of a type synonym, for exmaple.)
+                       -- However, *unsaturated* FunTyCons do appear as TyConApps.  
+                       -- 
        [Type]          -- Might not be saturated.
+                       -- Even type synonyms are not necessarily saturated;
+                       -- for example unsaturated type synonyms can appear as the 
+                       -- RHS of a type synonym.
 
   | FunTy              -- Special case of TyConApp: TyConApp FunTyCon [t1,t2]
        Type
@@ -175,12 +177,7 @@ data Type
        TyNote
        Type            -- The expanded version
 
-data TyNote
-  = FTVNote TyVarSet   -- The free type variables of the noted expression
-
-  | SynNote Type       -- Used for type synonyms
-                       -- The Type is always a TyConApp, and is the un-expanded form.
-                       -- The type to which the note is attached is the expanded form.
+data TyNote = FTVNote TyVarSet -- The free type variables of the noted expression
 \end{code}
 
 -------------------------------------
@@ -342,13 +339,10 @@ instance Outputable name => OutputableBndr (IPName name) where
        -- OK, here's the main printer
 
 ppr_type :: Prec -> Type -> SDoc
-ppr_type p (TyVarTy tv)              = ppr tv
-ppr_type p (PredTy pred)             = braces (ppr pred)
-ppr_type p (NoteTy (SynNote ty1) ty2) = ppr_type p ty1 
-                                       <+> ifPprDebug (braces $ ptext SLIT("Syn:") <+> pprType ty2)
-ppr_type p (NoteTy other         ty2) = ppr_type p ty2
-
-ppr_type p (TyConApp tc tys) = ppr_tc_app p tc tys
+ppr_type p (TyVarTy tv)       = ppr tv
+ppr_type p (PredTy pred)      = braces (ppr pred)
+ppr_type p (NoteTy other ty2) = ppr_type p ty2
+ppr_type p (TyConApp tc tys)  = ppr_tc_app p tc tys
 
 ppr_type p (AppTy t1 t2) = maybeParen p TyConPrec $
                           pprType t1 <+> ppr_type TyConPrec t2
@@ -372,14 +366,14 @@ ppr_forall_type p ty
     (tvs,  rho) = split1 [] ty
     (ctxt, tau) = split2 [] rho
 
-    split1 tvs (ForAllTy tv ty)        = split1 (tv:tvs) ty
-    split1 tvs (NoteTy (FTVNote _) ty) = split1 tvs ty
-    split1 tvs ty                     = (reverse tvs, ty)
+    split1 tvs (ForAllTy tv ty) = split1 (tv:tvs) ty
+    split1 tvs (NoteTy _ ty)    = split1 tvs ty
+    split1 tvs ty              = (reverse tvs, ty)
  
-    split2 ps (NoteTy (FTVNote _) arg  -- Rather a disgusting case
+    split2 ps (NoteTy _ arg    -- Rather a disgusting case
               `FunTy` res)           = split2 ps (arg `FunTy` res)
     split2 ps (PredTy p `FunTy` ty)   = split2 (p:ps) ty
-    split2 ps (NoteTy (FTVNote _) ty) = split2 ps ty
+    split2 ps (NoteTy _ ty)          = split2 ps ty
     split2 ps ty                     = (reverse ps, ty)
 
 ppr_tc_app :: Prec -> TyCon -> [Type] -> SDoc