Type, PredType, ThetaType,
Kind, TyVarSubst,
+ TyThing(..), isTyClThing,
+
superKind, superBoxity, -- KX and BX respectively
liftedBoxity, unliftedBoxity, -- :: BX
openKindCon, -- :: KX
isTypeKind, isAnyTypeKind,
funTyCon,
- usageKindCon, -- :: KX
- usageTypeKind, -- :: KX
- usOnceTyCon, usManyTyCon, -- :: $
- usOnce, usMany, -- :: $
-
-- exports from this module:
hasMoreBoxityInfo, defaultKind,
mkFunTy, mkFunTys, splitFunTy, splitFunTy_maybe, splitFunTys,
funResultTy, funArgTy, zipFunTys, isFunTy,
- mkTyConApp, mkTyConTy,
+ mkGenTyConApp, mkTyConApp, mkTyConTy,
tyConAppTyCon, tyConAppArgs,
splitTyConApp_maybe, splitTyConApp,
tidyTopType, tidyPred,
-- Comparison
- eqType, eqKind, eqUsage,
+ eqType, eqKind,
-- Seq
seqType, seqTypes
import {-# SOURCE #-} Subst ( substTyWith )
-- friends:
-import Var ( TyVar, tyVarKind, tyVarName, setTyVarName )
+import Var ( Id, TyVar, tyVarKind, tyVarName, setTyVarName )
import VarEnv
import VarSet
-import Name ( NamedThing(..), mkLocalName, tidyOccName )
-import Class ( classTyCon )
+import Name ( NamedThing(..), mkInternalName, tidyOccName )
+import Class ( Class, classTyCon )
import TyCon ( TyCon, isRecursiveTyCon, isPrimTyCon,
isUnboxedTupleTyCon, isUnLiftedTyCon,
isFunTyCon, isNewTyCon, newTyConRep,
import SrcLoc ( noSrcLoc )
import PrimRep ( PrimRep(..) )
import Unique ( Uniquable(..) )
-import Util ( mapAccumL, seqList, lengthIs )
+import Util ( mapAccumL, seqList, lengthIs, snocView )
import Outputable
import UniqSet ( sizeUniqSet ) -- Should come via VarSet
import Maybe ( isJust )
%************************************************************************
%* *
+ TyThing
+%* *
+%************************************************************************
+
+\begin{code}
+data TyThing = AnId Id
+ | ATyCon TyCon
+ | AClass Class
+
+isTyClThing :: TyThing -> Bool
+isTyClThing (ATyCon _) = True
+isTyClThing (AClass _) = True
+isTyClThing (AnId _) = False
+
+instance NamedThing TyThing where
+ getName (AnId id) = getName id
+ getName (ATyCon tc) = getName tc
+ getName (AClass cl) = getName cl
+\end{code}
+
+
+%************************************************************************
+%* *
\subsection{Stuff to do with kinds.}
%* *
%************************************************************************
mk_app orig_ty1
where
mk_app (NoteTy _ ty1) = mk_app ty1
- mk_app (TyConApp tc tys) = mkTyConApp tc (tys ++ [orig_ty2])
+ mk_app (TyConApp tc tys) = mkGenTyConApp tc (tys ++ [orig_ty2])
mk_app ty1 = AppTy orig_ty1 orig_ty2
+ -- We call mkGenTyConApp because the TyConApp could be an
+ -- under-saturated type synonym. GHC allows that; e.g.
+ -- type Foo k = k a -> k a
+ -- type Id x = x
+ -- foo :: Foo Id -> Foo Id
+ --
+ -- Here Id is partially applied in the type sig for Foo,
+ -- but once the type synonyms are expanded all is well
mkAppTys :: Type -> [Type] -> Type
mkAppTys orig_ty1 [] = orig_ty1
splitAppTy_maybe (FunTy ty1 ty2) = Just (TyConApp funTyCon [ty1], ty2)
splitAppTy_maybe (AppTy ty1 ty2) = Just (ty1, ty2)
splitAppTy_maybe (NoteTy _ ty) = splitAppTy_maybe ty
-splitAppTy_maybe (SourceTy p) = splitAppTy_maybe (sourceTypeRep p)
-splitAppTy_maybe (TyConApp tc []) = Nothing
-splitAppTy_maybe (TyConApp tc tys) = split tys []
- where
- split [ty2] acc = Just (TyConApp tc (reverse acc), ty2)
- split (ty:tys) acc = split tys (ty:acc)
-
-splitAppTy_maybe other = Nothing
+splitAppTy_maybe (SourceTy p) = splitAppTy_maybe (sourceTypeRep p)
+splitAppTy_maybe (TyConApp tc tys) = case snocView tys of
+ Nothing -> Nothing
+ Just (tys',ty') -> Just (TyConApp tc tys', ty')
+splitAppTy_maybe other = Nothing
splitAppTy :: Type -> (Type, Type)
splitAppTy ty = case splitAppTy_maybe ty of
where
split orig_ty (AppTy ty arg) args = split ty ty (arg:args)
split orig_ty (NoteTy _ ty) args = split orig_ty ty args
- split orig_ty (SourceTy p) args = split orig_ty (sourceTypeRep p) args
+ split orig_ty (SourceTy p) args = split orig_ty (sourceTypeRep p) args
split orig_ty (FunTy ty1 ty2) args = ASSERT( null args )
(TyConApp funTyCon [], [ty1,ty2])
split orig_ty (TyConApp tc tc_args) args = (TyConApp tc [], tc_args ++ args)
as apppropriate.
\begin{code}
+mkGenTyConApp :: TyCon -> [Type] -> Type
+mkGenTyConApp tc tys
+ | isSynTyCon tc = mkSynTy tc tys
+ | otherwise = mkTyConApp tc tys
+
mkTyConApp :: TyCon -> [Type] -> Type
-- Assumes TyCon is not a SynTyCon; use mkSynTy instead for those
mkTyConApp tycon tys
| n_args == arity -- Exactly saturated
= mk_syn tys
| n_args > arity -- Over-saturated
- = case splitAt arity tys of { (as,bs) -> foldl AppTy (mk_syn as) bs }
+ = case splitAt arity tys of { (as,bs) -> mkAppTys (mk_syn as) bs }
+ -- Its important to use mkAppTys, rather than (foldl AppTy),
+ -- because (mk_syn as) might well return a partially-applied
+ -- type constructor; indeed, usually will!
| otherwise -- Un-saturated
= TyConApp tycon tys
-- For the un-saturated case we build TyConApp directly
applyTy other arg = panic "applyTy"
applyTys :: Type -> [Type] -> Type
-applyTys fun_ty arg_tys
+applyTys orig_fun_ty arg_tys
= substTyWith tvs arg_tys ty
where
- (mu, tvs, ty) = split fun_ty arg_tys
+ (tvs, ty) = split orig_fun_ty arg_tys
- split fun_ty [] = (Nothing, [], fun_ty)
+ split fun_ty [] = ([], fun_ty)
split (NoteTy _ fun_ty) args = split fun_ty args
split (SourceTy p) args = split (sourceTypeRep p) args
split (ForAllTy tv fun_ty) (arg:args) = case split fun_ty args of
- (mu, tvs, ty) -> (mu, tv:tvs, ty)
+ (tvs, ty) -> (tv:tvs, ty)
split other_ty args = panic "applyTys"
+ -- No show instance for Type yet
\end{code}
tyVarsOfType (TyVarTy tv) = unitVarSet tv
tyVarsOfType (TyConApp tycon tys) = tyVarsOfTypes tys
tyVarsOfType (NoteTy (FTVNote tvs) ty2) = tvs
-tyVarsOfType (NoteTy (SynNote ty1) ty2) = tyVarsOfType ty1
+tyVarsOfType (NoteTy (SynNote ty1) ty2) = tyVarsOfType ty2 -- See note [Syn] below
tyVarsOfType (SourceTy sty) = tyVarsOfSourceType sty
tyVarsOfType (FunTy arg res) = tyVarsOfType arg `unionVarSet` tyVarsOfType res
tyVarsOfType (AppTy fun arg) = tyVarsOfType fun `unionVarSet` tyVarsOfType arg
tyVarsOfType (ForAllTy tyvar ty) = tyVarsOfType ty `minusVarSet` unitVarSet tyvar
+-- Note [Syn]
+-- Consider
+-- type T a = Int
+-- What are the free tyvars of (T x)? Empty, of course!
+-- Here's the example that Ralf Laemmel showed me:
+-- foo :: (forall a. C u a -> C u a) -> u
+-- mappend :: Monoid u => u -> u -> u
+--
+-- bar :: Monoid u => u
+-- bar = foo (\t -> t `mappend` t)
+-- We have to generalise at the arg to f, and we don't
+-- want to capture the constraint (Monad (C u a)) because
+-- it appears to mention a. Pretty silly, but it was useful to him.
+
+
tyVarsOfTypes :: [Type] -> TyVarSet
tyVarsOfTypes tys = foldr (unionVarSet.tyVarsOfType) emptyVarSet tys
addFreeTyVars ty = NoteTy (FTVNote (tyVarsOfType ty)) ty
\end{code}
-
-
%************************************************************************
%* *
\subsection{TidyType}
where
subst' = extendVarEnv subst tyvar tyvar'
tyvar' = setTyVarName tyvar name'
- name' = mkLocalName (getUnique name) occ' noSrcLoc
+ name' = mkInternalName (getUnique name) occ' noSrcLoc
-- Note: make a *user* tyvar, so it printes nicely
-- Could extract src loc, but no need.
where
\begin{code}
eqType t1 t2 = eq_ty emptyVarEnv t1 t2
eqKind = eqType -- No worries about looking
-eqUsage = eqType -- through source types for these two
-- Look through Notes
eq_ty env (NoteTy _ t1) t2 = eq_ty env t1 t2
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