[project @ 2003-04-16 13:34:13 by simonpj]

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

diff --git a/ghc/compiler/typecheck/TcType.lhs b/ghc/compiler/typecheck/TcType.lhs
index f41c7a4..e2ec116 100644 (file)
--- a/ghc/compiler/typecheck/TcType.lhs
+++ b/ghc/compiler/typecheck/TcType.lhs
@@ -16,13 +16,17 @@ is the principal client.
 \begin{code}
 module TcType (
   --------------------------------
+  -- TyThing
+  TyThing(..), -- instance NamedThing
+
+  --------------------------------
   -- Types 
   TcType, TcSigmaType, TcRhoType, TcTauType, TcPredType, TcThetaType, 
   TcTyVar, TcTyVarSet, TcKind, 
 
   --------------------------------
   -- TyVarDetails
-  TyVarDetails(..), isUserTyVar, isSkolemTyVar, isHoleTyVar, 
+  TyVarDetails(..), isUserTyVar, isSkolemTyVar, 
   tyVarBindingInfo,
 
   --------------------------------
@@ -96,7 +100,7 @@ module TcType (
 
   tidyTopType, tidyType, tidyPred, tidyTypes, tidyFreeTyVars, tidyOpenType, tidyOpenTypes,
   tidyTyVarBndr, tidyOpenTyVar, tidyOpenTyVars,
-  typeKind, eqKind, eqUsage,
+  typeKind, eqKind,
 
   tyVarsOfType, tyVarsOfTypes, tyVarsOfPred, tyVarsOfTheta
   ) where
@@ -123,17 +127,18 @@ import Type               (       -- Re-exports
                          mkTyVarTy, mkTyVarTys, mkTyConTy, mkPredTy,
                          mkPredTys, isUnLiftedType,
                          isUnboxedTupleType, isPrimitiveType,
-                         splitNewType_maybe, splitTyConApp_maybe,
+                         splitTyConApp_maybe,
                          tidyTopType, tidyType, tidyPred, tidyTypes,
                          tidyFreeTyVars, tidyOpenType, tidyOpenTypes,
                          tidyTyVarBndr, tidyOpenTyVar,
-                         tidyOpenTyVars, eqKind, eqUsage,
+                         tidyOpenTyVars, eqKind, 
                          hasMoreBoxityInfo, liftedBoxity,
                          superBoxity, typeKind, superKind, repType
                        )
+import DataCon         ( DataCon )
 import TyCon           ( TyCon, isUnLiftedTyCon )
 import Class           ( classHasFDs, Class )
-import Var             ( TyVar, tyVarKind, isMutTyVar, mutTyVarDetails )
+import Var             ( TyVar, Id, tyVarKind, isMutTyVar, mutTyVarDetails )
 import ForeignCall     ( Safety, playSafe )
 import VarEnv
 import VarSet
@@ -156,6 +161,26 @@ import Outputable
 
 %************************************************************************
 %*                                                                     *
+                       TyThing
+%*                                                                     *
+%************************************************************************
+
+\begin{code}
+data TyThing = AnId     Id
+            | ADataCon DataCon
+            | ATyCon   TyCon
+            | AClass   Class
+
+instance NamedThing TyThing where
+  getName (AnId id)     = getName id
+  getName (ATyCon tc)   = getName tc
+  getName (AClass cl)   = getName cl
+  getName (ADataCon dc) = getName dc
+\end{code}
+
+
+%************************************************************************
+%*                                                                     *
 \subsection{Types}
 %*                                                                     *
 %************************************************************************
@@ -228,12 +253,7 @@ why Var.lhs shouldn't actually have the definition, but it "belongs" here.
 
 \begin{code}
 data TyVarDetails
-  = HoleTv     -- Used *only* by the type checker when passing in a type
-               -- variable that should be side-effected to the result type.
-               -- Always has kind openTypeKind.
-               -- Never appears in types
-
-  | SigTv      -- Introduced when instantiating a type signature,
+  = SigTv      -- Introduced when instantiating a type signature,
                -- prior to checking that the defn of a fn does 
                -- have the expected type.  Should not be instantiated.
                --
@@ -265,14 +285,6 @@ isSkolemTyVar tv = case mutTyVarDetails tv of
                      InstTv -> True
                      oteher -> False
 
-isHoleTyVar :: TcTyVar -> Bool
--- NB:  the hole might be filled in by now, and this
---     function does not check for that
-isHoleTyVar tv = ASSERT( isMutTyVar tv )
-                case mutTyVarDetails tv of
-                       HoleTv -> True
-                       other  -> False
-
 tyVarBindingInfo :: TyVar -> SDoc      -- Used in checkSigTyVars
 tyVarBindingInfo tv
   | isMutTyVar tv
@@ -285,7 +297,6 @@ tyVarBindingInfo tv
     details ClsTv     = ptext SLIT("class declaration")
     details InstTv    = ptext SLIT("instance declaration")
     details PatSigTv  = ptext SLIT("pattern type signature")
-    details HoleTv    = ptext SLIT("//hole//")         -- Should not happen
     details VanillaTv = ptext SLIT("//vanilla//")      -- Ditto
 \end{code}
 
@@ -449,8 +460,7 @@ The type of a method for class C is always of the form:
 where sig_ty is the type given by the method's signature, and thus in general
 is a ForallTy.  At the point that splitMethodTy is called, it is expected
 that the outer Forall has already been stripped off.  splitMethodTy then
-returns (C a1..an, sig_ty') where sig_ty' is sig_ty with any Notes or
-Usages stripped off.
+returns (C a1..an, sig_ty') where sig_ty' is sig_ty with any Notes stripped off.
 
 \begin{code}
 tcSplitMethodTy :: Type -> (PredType, Type)
@@ -829,7 +839,7 @@ isFFILabelTy = checkRepTyCon (\tc -> tc == ptrTyCon || tc == funPtrTyCon || tc =
 checkRepTyCon :: (TyCon -> Bool) -> Type -> Bool
        -- Look through newtypes
        -- Non-recursive ones are transparent to splitTyConApp,
-       -- but recursive ones aren't; hence the splitNewType_maybe
+       -- but recursive ones aren't
 checkRepTyCon check_tc ty 
   | Just (tc,_) <- splitTyConApp_maybe (repType ty) = check_tc tc
   | otherwise                                      = False