Fix scoped type variables for expression type signatures

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

diff --git a/compiler/types/Type.lhs b/compiler/types/Type.lhs
index c3013ab..7c05b6d 100644 (file)
--- a/compiler/types/Type.lhs
+++ b/compiler/types/Type.lhs
@@ -12,7 +12,7 @@ module Type (
 
        -- Kinds
         Kind, SimpleKind, KindVar,
-        kindFunResult, splitKindFunTys, 
+        kindFunResult, splitKindFunTys, splitKindFunTysN,
 
         liftedTypeKindTyCon, openTypeKindTyCon, unliftedTypeKindTyCon,
         argTypeKindTyCon, ubxTupleKindTyCon,
@@ -24,7 +24,7 @@ module Type (
 
         isLiftedTypeKind, isUnliftedTypeKind, isOpenTypeKind,
         isUbxTupleKind, isArgTypeKind, isKind, isTySuperKind, 
-        isCoSuperKind, isSuperKind, isCoercionKind,
+        isCoSuperKind, isSuperKind, isCoercionKind, isEqPred,
        mkArrowKind, mkArrowKinds,
 
         isSubArgTypeKind, isSubOpenTypeKind, isSubKind, defaultKind, eqKind,
@@ -106,7 +106,7 @@ import TypeRep
 
 -- friends:
 import Var     ( Var, TyVar, tyVarKind, tyVarName, 
-                 setTyVarName, setTyVarKind )
+                 setTyVarName, setTyVarKind, mkWildCoVar )
 import VarEnv
 import VarSet
 
@@ -117,11 +117,12 @@ import PrelNames( openTypeKindTyConKey, unliftedTypeKindTyConKey,
                   ubxTupleKindTyConKey, argTypeKindTyConKey )
 import TyCon   ( TyCon, isRecursiveTyCon, isPrimTyCon,
                  isUnboxedTupleTyCon, isUnLiftedTyCon,
-                 isFunTyCon, isNewTyCon, newTyConRep, newTyConRhs,
+                 isFunTyCon, isNewTyCon, isClosedNewTyCon, 
+                 newTyConRep, newTyConRhs, 
                  isAlgTyCon, tyConArity, isSuperKindTyCon,
                  tcExpandTyCon_maybe, coreExpandTyCon_maybe,
                  tyConKind, PrimRep(..), tyConPrimRep, tyConUnique,
-                  isCoercionTyCon_maybe, isCoercionTyCon
+                  isCoercionTyCon
                )
 
 -- others
@@ -164,7 +165,9 @@ coreView :: Type -> Maybe Type
 -- By being non-recursive and inlined, this case analysis gets efficiently
 -- joined onto the case analysis that the caller is already doing
 coreView (NoteTy _ ty)            = Just ty
-coreView (PredTy p)               = Just (predTypeRep p)
+coreView (PredTy p)
+  | isEqPred p             = Nothing
+  | otherwise             = Just (predTypeRep p)
 coreView (TyConApp tc tys) | Just (tenv, rhs, tys') <- coreExpandTyCon_maybe tc tys 
                           = Just (mkAppTys (substTy (mkTopTvSubst tenv) rhs) tys')
                                -- Its important to use mkAppTys, rather than (foldl AppTy),
@@ -305,10 +308,11 @@ splitAppTys ty = split ty ty []
 
 \begin{code}
 mkFunTy :: Type -> Type -> Type
+mkFunTy (PredTy (EqPred ty1 ty2)) res = mkForAllTy (mkWildCoVar (PredTy (EqPred ty1 ty2))) res
 mkFunTy arg res = FunTy arg res
 
 mkFunTys :: [Type] -> Type -> Type
-mkFunTys tys ty = foldr FunTy ty tys
+mkFunTys tys ty = foldr mkFunTy ty tys
 
 isFunTy :: Type -> Bool 
 isFunTy ty = isJust (splitFunTy_maybe ty)
@@ -445,7 +449,7 @@ repType looks through
        (b) synonyms
        (c) predicates
        (d) usage annotations
-       (e) all newtypes, including recursive ones
+       (e) all newtypes, including recursive ones, but not newtype families
 It's useful in the back end.
 
 \begin{code}
@@ -454,7 +458,7 @@ repType :: Type -> Type
 repType ty | Just ty' <- coreView ty = repType ty'
 repType (ForAllTy _ ty)  = repType ty
 repType (TyConApp tc tys)
-  | isNewTyCon tc       = -- Recursive newtypes are opaque to coreView
+  | isClosedNewTyCon tc  = -- Recursive newtypes are opaque to coreView
                           -- but we must expand them here.  Sure to
                           -- be saturated because repType is only applied
                           -- to types of kind *
@@ -596,6 +600,7 @@ predTypeRep (IParam _ ty)     = ty
 predTypeRep (ClassP clas tys) = mkTyConApp (classTyCon clas) tys
        -- Result might be a newtype application, but the consumer will
        -- look through that too if necessary
+predTypeRep (EqPred ty1 ty2) = pprPanic "predTypeRep" (ppr (EqPred ty1 ty2))
 \end{code}
 
 
@@ -612,7 +617,7 @@ splitRecNewType_maybe :: Type -> Maybe Type
 -- Only applied to types of kind *, hence the newtype is always saturated
 splitRecNewType_maybe ty | Just ty' <- coreView ty = splitRecNewType_maybe ty'
 splitRecNewType_maybe (TyConApp tc tys)
-  | isNewTyCon tc
+  | isClosedNewTyCon tc
   = ASSERT( tys `lengthIs` tyConArity tc )     -- splitRecNewType_maybe only be applied 
                                                --      to *types* (of kind *)
     ASSERT( isRecursiveTyCon tc )              -- Guaranteed by coreView
@@ -1023,8 +1028,13 @@ cmpPredX env (IParam n1 ty1) (IParam n2 ty2) = (n1 `compare` n2) `thenCmp` cmpTy
        -- This comparison is used exclusively (I think) for the
        -- finite map built in TcSimplify
 cmpPredX env (ClassP c1 tys1) (ClassP c2 tys2) = (c1 `compare` c2) `thenCmp` cmpTypesX env tys1 tys2
-cmpPredX env (IParam _ _)     (ClassP _ _)     = LT
-cmpPredX env (ClassP _ _)     (IParam _ _)     = GT
+cmpPredX env (EqPred ty1 ty2) (EqPred ty1' ty2') = (cmpTypeX env ty1 ty1') `thenCmp` (cmpTypeX env ty2 ty2')
+
+-- Constructor order: IParam < ClassP < EqPred
+cmpPredX env (IParam {})     _             = LT
+cmpPredX env (ClassP {})    (IParam {})     = GT
+cmpPredX env (ClassP {})    (EqPred {})     = LT
+cmpPredX env (EqPred {})    _              = GT
 \end{code}
 
 PredTypes are used as a FM key in TcSimplify, 
@@ -1366,6 +1376,9 @@ kindFunResult k = funResultTy k
 splitKindFunTys :: Kind -> ([Kind],Kind)
 splitKindFunTys k = splitFunTys k
 
+splitKindFunTysN :: Int -> Kind -> ([Kind],Kind)
+splitKindFunTysN k = splitFunTysN k
+
 isUbxTupleKind, isOpenTypeKind, isArgTypeKind, isUnliftedTypeKind :: Kind -> Bool
 
 isOpenTypeKindCon tc    = tyConUnique tc == openTypeKindTyConKey
@@ -1421,8 +1434,10 @@ isKind k = isSuperKind (typeKind k)
 
 isSubKind :: Kind -> Kind -> Bool
 -- (k1 `isSubKind` k2) checks that k1 <: k2
-isSubKind (TyConApp kc1 []) (TyConApp kc2 []) = kc1 `isSubKindCon` kc1
+isSubKind (TyConApp kc1 []) (TyConApp kc2 []) = kc1 `isSubKindCon` kc2
 isSubKind (FunTy a1 r1) (FunTy a2 r2)        = (a2 `isSubKind` a1) && (r1 `isSubKind` r2)
+isSubKind (PredTy (EqPred ty1 ty2)) (PredTy (EqPred ty1' ty2')) 
+  = ty1 `tcEqType` ty1' && ty2 `tcEqType` ty2'
 isSubKind k1           k2                    = False
 
 eqKind :: Kind -> Kind -> Bool
@@ -1465,4 +1480,8 @@ isCoercionKind :: Kind -> Bool
 isCoercionKind k | Just k' <- kindView k = isCoercionKind k'
 isCoercionKind (PredTy (EqPred {}))     = True
 isCoercionKind other                    = False
+
+isEqPred :: PredType -> Bool
+isEqPred (EqPred _ _) = True
+isEqPred other       = False
 \end{code}