[project @ 2003-12-30 16:29:17 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 8815cf5..ffcf392 100644 (file)
--- a/ghc/compiler/typecheck/TcType.lhs
+++ b/ghc/compiler/typecheck/TcType.lhs
@@ -85,9 +85,9 @@ module TcType (
   -- Rexported from Type
   Kind,        -- Stuff to do with kinds is insensitive to pre/post Tc
   unliftedTypeKind, liftedTypeKind, openTypeKind, mkArrowKind, mkArrowKinds, 
-  isLiftedTypeKind, isUnliftedTypeKind, isOpenTypeKind, isSuperKind,
-  superBoxity, liftedBoxity, hasMoreBoxityInfo, defaultKind, superKind,
-  isTypeKind, isAnyTypeKind, typeCon,
+  isLiftedTypeKind, isUnliftedTypeKind, isOpenTypeKind, 
+  isSubKind, defaultKind, 
+  isArgTypeKind, isOpenTypeKind, 
 
   Type, PredType(..), ThetaType, 
   mkForAllTy, mkForAllTys, 
@@ -101,7 +101,7 @@ module TcType (
 
   tidyTopType, tidyType, tidyPred, tidyTypes, tidyFreeTyVars, tidyOpenType, tidyOpenTypes,
   tidyTyVarBndr, tidyOpenTyVar, tidyOpenTyVars,
-  typeKind, eqKind,
+  typeKind, 
 
   tyVarsOfType, tyVarsOfTypes, tyVarsOfPred, tyVarsOfTheta,
 
@@ -119,12 +119,12 @@ import TypeRep            ( Type(..), TyNote(..), funTyCon )  -- friend
 import Type            (       -- Re-exports
                          tyVarsOfType, tyVarsOfTypes, tyVarsOfPred,
                          tyVarsOfTheta, Kind, Type, PredType(..),
-                         ThetaType, unliftedTypeKind, typeCon,
+                         ThetaType, unliftedTypeKind, 
                          liftedTypeKind, openTypeKind, mkArrowKind,
                          isLiftedTypeKind, isUnliftedTypeKind, 
-                         isOpenTypeKind, isSuperKind,
+                         isOpenTypeKind, 
                          mkArrowKinds, mkForAllTy, mkForAllTys,
-                         defaultKind, isTypeKind, isAnyTypeKind,
+                         defaultKind, isArgTypeKind, isOpenTypeKind,
                          mkFunTy, mkFunTys, zipFunTys, 
                          mkTyConApp, mkGenTyConApp, mkAppTy,
                          mkAppTys, mkSynTy, applyTy, applyTys,
@@ -135,19 +135,17 @@ import Type               (       -- Re-exports
                          tidyTopType, tidyType, tidyPred, tidyTypes,
                          tidyFreeTyVars, tidyOpenType, tidyOpenTypes,
                          tidyTyVarBndr, tidyOpenTyVar,
-                         tidyOpenTyVars, eqKind, 
-                         hasMoreBoxityInfo, liftedBoxity,
-                         superBoxity, typeKind, superKind, repType,
+                         tidyOpenTyVars, 
+                         isSubKind, 
+                         typeKind, repType,
                          pprKind, pprParendKind,
                          pprType, pprParendType,
                          pprPred, pprTheta, pprThetaArrow, pprClassPred
                        )
 import TyCon           ( TyCon, isUnLiftedTyCon, tyConUnique )
 import Class           ( Class )
-import Var             ( TyVar, tyVarKind, isMutTyVar, mutTyVarDetails )
-import ForeignCall     ( Safety, playSafe
-                         , DNType(..)
-                       )
+import Var             ( TyVar, tyVarKind, tcTyVarDetails )
+import ForeignCall     ( Safety, playSafe, DNType(..) )
 import VarEnv
 import VarSet
 
@@ -203,9 +201,6 @@ tau ::= tyvar
 -- provided it expands to the required form.
 
 \begin{code}
-type TcTyVar    = TyVar                -- Might be a mutable tyvar
-type TcTyVarSet = TyVarSet
-
 type TcType = Type             -- A TcType can have mutable type variables
        -- Invariant on ForAllTy in TcTypes:
        --      forall a. T
@@ -217,7 +212,8 @@ type TcThetaType    = ThetaType
 type TcSigmaType    = TcType
 type TcRhoType      = TcType
 type TcTauType      = TcType
-type TcKind         = TcType
+
+type TcKind         = Kind
 \end{code}
 
 
@@ -233,11 +229,12 @@ It's knot-tied back to Var.lhs.  There is no reason in principle
 why Var.lhs shouldn't actually have the definition, but it "belongs" here.
 
 \begin{code}
+type TcTyVar = TyVar   -- Used only during type inference
+
 data TyVarDetails
   = 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.
-               --
                --      f :: forall a. a -> a
                --      f = e
                -- When checking e, with expected type (a->a), we 
@@ -249,30 +246,26 @@ data TyVarDetails
    | InstTv    -- Ditto, but instance decl
 
    | PatSigTv  -- Scoped type variable, introduced by a pattern
-               -- type signature
-               --      \ x::a -> e
+               -- type signature       \ x::a -> e
 
    | VanillaTv -- Everything else
 
 isUserTyVar :: TcTyVar -> Bool -- Avoid unifying these if possible
-isUserTyVar tv = case mutTyVarDetails tv of
+isUserTyVar tv = case tcTyVarDetails tv of
                   VanillaTv -> False
                   other     -> True
 
 isSkolemTyVar :: TcTyVar -> Bool
-isSkolemTyVar tv = case mutTyVarDetails tv of
+isSkolemTyVar tv = case tcTyVarDetails tv of
                      SigTv  -> True
                      ClsTv  -> True
                      InstTv -> True
                      oteher -> False
 
-tyVarBindingInfo :: TyVar -> SDoc      -- Used in checkSigTyVars
+tyVarBindingInfo :: TcTyVar -> SDoc    -- Used in checkSigTyVars
 tyVarBindingInfo tv
-  | isMutTyVar tv
-  = sep [ptext SLIT("is bound by the") <+> details (mutTyVarDetails tv),
+  = sep [ptext SLIT("is bound by the") <+> details (tcTyVarDetails tv),
         ptext SLIT("at") <+> ppr (getSrcLoc tv)]
-  | otherwise
-  = empty
   where
     details SigTv     = ptext SLIT("type signature")
     details ClsTv     = ptext SLIT("class declaration")
@@ -281,6 +274,9 @@ tyVarBindingInfo tv
     details VanillaTv = ptext SLIT("//vanilla//")      -- Ditto
 \end{code}
 
+\begin{code}
+type TcTyVarSet = TyVarSet
+\end{code}
 
 %************************************************************************
 %*                                                                     *
@@ -1046,7 +1042,7 @@ uVarX tv1 ty2 k subst@(tmpls, env)
                     uTysX ty1 ty2 k subst
 
       Nothing       -- Not already bound
-              |  typeKind ty2 `eqKind` tyVarKind tv1
+              |  typeKind ty2 == tyVarKind tv1
               && occur_check_ok ty2
               ->     -- No kind mismatch nor occur check
                   k (tmpls, extendSubstEnv env tv1 (DoneTy ty2))
@@ -1116,7 +1112,7 @@ match (TyVarTy v) ty tmpls k senv
   | v `elemVarSet` tmpls
   =     -- v is a template variable
     case lookupSubstEnv senv v of
-       Nothing | typeKind ty `eqKind` tyVarKind v      
+       Nothing | typeKind ty == tyVarKind v    
                        -- We do a kind check, just as in the uVarX above
                        -- The kind check is needed to avoid bogus matches
                        -- of (a b) with (c d), where the kinds don't match