Properly ppr InstEqs in wanteds of implication constraints

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

diff --git a/compiler/types/Type.lhs b/compiler/types/Type.lhs
index cd484f4..662dd6f 100644 (file)
--- a/compiler/types/Type.lhs
+++ b/compiler/types/Type.lhs
@@ -55,7 +55,7 @@ module Type (
        splitTyConApp_maybe, splitTyConApp, 
         splitNewTyConApp_maybe, splitNewTyConApp,
 
-       repType, repType', typePrimRep, coreView, tcView, kindView,
+       repType, typePrimRep, coreView, tcView, kindView, rttiView,
 
        mkForAllTy, mkForAllTys, splitForAllTy_maybe, splitForAllTys, 
        applyTy, applyTys, isForAllTy, dropForAlls,
@@ -67,8 +67,8 @@ module Type (
        newTyConInstRhs,
 
        -- Lifting and boxity
-       isUnLiftedType, isUnboxedTupleType, isAlgType, isPrimitiveType,
-       isStrictType, isStrictPred, 
+       isUnLiftedType, isUnboxedTupleType, isAlgType, isClosedAlgType,
+       isPrimitiveType, isStrictType, isStrictPred, 
 
        -- Free variables
        tyVarsOfType, tyVarsOfTypes, tyVarsOfPred, tyVarsOfTheta,
@@ -190,6 +190,18 @@ tcView (TyConApp tc tys) | Just (tenv, rhs, tys') <- tcExpandTyCon_maybe tc tys
 tcView ty               = Nothing
 
 -----------------------------------------------
+rttiView :: Type -> Type
+-- Same, but for the RTTI system, which cannot deal with predicates nor polymorphism
+rttiView (ForAllTy _ ty) = rttiView ty
+rttiView (NoteTy   _ ty) = rttiView ty
+rttiView (FunTy PredTy{} ty) = rttiView ty
+rttiView (FunTy NoteTy{} ty) = rttiView ty
+rttiView ty@TyConApp{} | Just ty' <- coreView ty 
+                           = rttiView ty'
+rttiView (TyConApp tc tys) = mkTyConApp tc (map rttiView tys)
+rttiView ty = ty
+
+-----------------------------------------------
 {-# INLINE kindView #-}
 kindView :: Kind -> Maybe Kind
 -- C.f. coreView, tcView
@@ -281,10 +293,12 @@ repSplitAppTy_maybe :: Type -> Maybe (Type,Type)
 -- Does the AppTy split, but assumes that any view stuff is already done
 repSplitAppTy_maybe (FunTy ty1 ty2)   = Just (TyConApp funTyCon [ty1], ty2)
 repSplitAppTy_maybe (AppTy ty1 ty2)   = Just (ty1, ty2)
-repSplitAppTy_maybe (TyConApp tc tys) = case snocView tys of
-                                               Just (tys', ty') -> Just (TyConApp tc tys', ty')
-                                               Nothing          -> Nothing
-repSplitAppTy_maybe other = Nothing
+repSplitAppTy_maybe (TyConApp tc tys) 
+  | not (isOpenSynTyCon tc) || length tys > tyConArity tc 
+  = case snocView tys of       -- never create unsaturated type family apps
+      Just (tys', ty') -> Just (TyConApp tc tys', ty')
+      Nothing         -> Nothing
+repSplitAppTy_maybe _other = Nothing
 -------------
 splitAppTy :: Type -> (Type, Type)
 splitAppTy ty = case splitAppTy_maybe ty of
@@ -297,7 +311,13 @@ splitAppTys ty = split ty ty []
   where
     split orig_ty ty args | Just ty' <- coreView ty = split orig_ty ty' args
     split orig_ty (AppTy ty arg)        args = split ty ty (arg:args)
-    split orig_ty (TyConApp tc tc_args) args = (TyConApp tc [], tc_args ++ args)
+    split orig_ty (TyConApp tc tc_args) args 
+      = let -- keep type families saturated
+            n | isOpenSynTyCon tc = tyConArity tc
+              | otherwise         = 0
+            (tc_args1, tc_args2)  = splitAt n tc_args
+        in
+        (TyConApp tc tc_args1, tc_args2 ++ args)
     split orig_ty (FunTy ty1 ty2)       args = ASSERT( null args )
                                               (TyConApp funTyCon [], [ty1,ty2])
     split orig_ty ty                   args = (orig_ty, args)
@@ -475,16 +495,6 @@ repType (TyConApp tc tys)
 
 repType ty = ty
 
--- repType' aims to be a more thorough version of repType
--- For now it simply looks through the TyConApp args too
-repType' ty -- | pprTrace "repType'" (ppr ty $$ ppr (go1 ty)) False = undefined
-            | otherwise = go1 ty 
- where 
-        go1 = go . repType
-        go (TyConApp tc tys) = mkTyConApp tc (map repType' tys)
-        go ty = ty
-
-
 -- ToDo: this could be moved to the code generator, using splitTyConApp instead
 -- of inspecting the type directly.
 typePrimRep :: Type -> PrimRep
@@ -853,10 +863,19 @@ isUnboxedTupleType ty = case splitTyConApp_maybe ty of
 
 -- Should only be applied to *types*; hence the assert
 isAlgType :: Type -> Bool
-isAlgType ty = case splitTyConApp_maybe ty of
-                       Just (tc, ty_args) -> ASSERT( ty_args `lengthIs` tyConArity tc )
-                                             isAlgTyCon tc
-                       other              -> False
+isAlgType ty 
+  = case splitTyConApp_maybe ty of
+      Just (tc, ty_args) -> ASSERT( ty_args `lengthIs` tyConArity tc )
+                           isAlgTyCon tc
+      _other            -> False
+
+-- Should only be applied to *types*; hence the assert
+isClosedAlgType :: Type -> Bool
+isClosedAlgType ty
+  = case splitTyConApp_maybe ty of
+      Just (tc, ty_args) -> ASSERT( ty_args `lengthIs` tyConArity tc )
+                           isAlgTyCon tc && not (isOpenTyCon tc)
+      _other            -> False
 \end{code}
 
 @isStrictType@ computes whether an argument (or let RHS) should