[project @ 2001-05-21 09:19:14 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 3d260dd..3f6831b 100644 (file)
--- a/ghc/compiler/typecheck/TcType.lhs
+++ b/ghc/compiler/typecheck/TcType.lhs
@@ -13,7 +13,7 @@ module TcType (
   newTyVarTys,         -- Int -> Kind -> NF_TcM [TcType]
 
   -----------------------------------------
-  TcType, TcTauType, TcThetaType, TcRhoType, TcClassContext,
+  TcType, TcTauType, TcThetaType, TcRhoType,
 
        -- Find the type to which a type variable is bound
   tcPutTyVar,          -- :: TcTyVar -> TcType -> NF_TcM TcType
@@ -23,7 +23,7 @@ module TcType (
   tcSplitRhoTy,
 
   tcInstTyVar, tcInstTyVars,
-  tcInstSigVar,
+  tcInstSigVars,
   tcInstType,
 
   --------------------------------
@@ -33,6 +33,7 @@ module TcType (
   --------------------------------
   zonkTcTyVar, zonkTcTyVars, zonkTcTyVarsAndFV, zonkTcSigTyVars,
   zonkTcType, zonkTcTypes, zonkTcClassConstraints, zonkTcThetaType,
+  zonkTcPredType,
 
   zonkTcTypeToType, zonkTcTyVarToTyVar, zonkKindEnv
 
@@ -170,14 +171,14 @@ tcInstTyVar tyvar
     in
     tcNewMutTyVar name (tyVarKind tyvar)
 
-tcInstSigVar tyvar     -- Very similar to tcInstTyVar
-  = tcGetUnique        `thenNF_Tc` \ uniq ->
-    let 
-       name = setNameUnique (tyVarName tyvar) uniq
-       kind = tyVarKind tyvar
-    in
-    ASSERT( not (kind == openTypeKind) )       -- Shouldn't happen
-    tcNewSigTyVar name kind
+tcInstSigVars tyvars   -- Very similar to tcInstTyVar
+  = tcGetUniques       `thenNF_Tc` \ uniqs ->
+    listTc [ ASSERT( not (kind == openTypeKind) )      -- Shouldn't happen
+            tcNewSigTyVar name kind 
+          | (tyvar, uniq) <- tyvars `zip` uniqs,
+            let name = setNameUnique (tyVarName tyvar) uniq, 
+            let kind = tyVarKind tyvar
+          ]
 \end{code}
 
 @tcInstType@ instantiates the outer-level for-alls of a TcType with
@@ -187,7 +188,11 @@ fresh type variables, splits off the dictionary part, and returns the results.
 tcInstType :: TcType -> NF_TcM ([TcTyVar], TcThetaType, TcType)
 tcInstType ty
   = case splitForAllTys ty of
-       ([],     _)   -> returnNF_Tc ([], [], ty)        -- Nothing to do
+       ([],     rho) ->        -- There may be overloading but no type variables;
+                               --      (?x :: Int) => Int -> Int
+                        tcSplitRhoTy rho                       `thenNF_Tc` \ (theta, tau) ->
+                        returnNF_Tc ([], theta, tau)
+
        (tyvars, rho) -> tcInstTyVars tyvars                    `thenNF_Tc` \ (tyvars', _, tenv)  ->
                         tcSplitRhoTy (substTy tenv rho)        `thenNF_Tc` \ (theta, tau) ->
                         returnNF_Tc (tyvars', theta, tau)
@@ -313,9 +318,9 @@ zonkTcThetaType :: TcThetaType -> NF_TcM TcThetaType
 zonkTcThetaType theta = mapNF_Tc zonkTcPredType theta
 
 zonkTcPredType :: TcPredType -> NF_TcM TcPredType
-zonkTcPredType (Class c ts) =
+zonkTcPredType (ClassP c ts) =
     zonkTcTypes ts     `thenNF_Tc` \ new_ts ->
-    returnNF_Tc (Class c new_ts)
+    returnNF_Tc (ClassP c new_ts)
 zonkTcPredType (IParam n t) =
     zonkTcType t       `thenNF_Tc` \ new_t ->
     returnNF_Tc (IParam n new_t)
@@ -346,7 +351,7 @@ zonkTcTypeToType ty = zonkType zonk_unbound_tyvar ty
        --      Void            if it has kind Lifted
        --      :Void           otherwise
     zonk_unbound_tyvar tv
-       | kind == liftedTypeKind
+       | kind == liftedTypeKind || kind == openTypeKind
        = tcPutTyVar tv voidTy  -- Just to avoid creating a new tycon in
                                -- this vastly common case
        | otherwise
@@ -446,8 +451,8 @@ zonkType unbound_var_fn ty
                             go ty                      `thenNF_Tc` \ ty' ->
                             returnNF_Tc (ForAllTy tyvar' ty')
 
-    go_pred (Class c tys) = mapNF_Tc go tys    `thenNF_Tc` \ tys' ->
-                           returnNF_Tc (Class c tys')
+    go_pred (ClassP c tys) = mapNF_Tc go tys   `thenNF_Tc` \ tys' ->
+                            returnNF_Tc (ClassP c tys')
     go_pred (IParam n ty) = go ty              `thenNF_Tc` \ ty' ->
                            returnNF_Tc (IParam n ty')