SynTyConRhs(..),
isFunTyCon, isUnLiftedTyCon, isProductTyCon,
- isAlgTyCon, isDataTyCon, isSynTyCon, isNewTyCon, isPrimTyCon,
+ isAlgTyCon, isDataTyCon, isSynTyCon, isNewTyCon, isClosedNewTyCon,
+ isPrimTyCon,
isEnumerationTyCon, isGadtSyntaxTyCon, isOpenTyCon,
+ assocTyConArgPoss_maybe, isTyConAssoc, setTyConArgPoss,
isTupleTyCon, isUnboxedTupleTyCon, isBoxedTupleTyCon, tupleTyConBoxity,
- isRecursiveTyCon, newTyConRep, newTyConRhs, newTyConCo,
+ isRecursiveTyCon, newTyConRep, newTyConRhs, newTyConCo_maybe,
isHiBootTyCon, isSuperKindTyCon,
isCoercionTyCon_maybe, isCoercionTyCon,
tyConStupidTheta,
tyConArity,
isClassTyCon, tyConClass_maybe,
- isFamInstTyCon, tyConFamily_maybe,
+ isFamInstTyCon, tyConFamInst_maybe, tyConFamilyCoercion_maybe,
synTyConDefn, synTyConRhs, synTyConType, synTyConResKind,
tyConExtName, -- External name for foreign types
#include "HsVersions.h"
-import {-# SOURCE #-} TypeRep ( Kind, Type, Coercion, PredType )
+import {-# SOURCE #-} TypeRep ( Kind, Type, PredType )
import {-# SOURCE #-} DataCon ( DataCon, isVanillaDataCon )
import Var ( TyVar, Id )
import BasicTypes ( Arity, RecFlag(..), Boxity(..), isBoxed )
import Name ( Name, nameUnique, NamedThing(getName) )
import PrelNames ( Unique, Uniquable(..) )
+import Maybe ( isJust )
import Maybes ( orElse )
import Outputable
import FastString
tyConName :: Name,
tyConKind :: Kind,
tyConArity :: Arity,
-
+
tyConTyVars :: [TyVar], -- Scopes over (a) the algTcStupidTheta
-- (b) the cached types in
-- algTyConRhs.NewTyCon
+ -- (c) the family instance
+ -- types if present
-- But not over the data constructors
+
+ tyConArgPoss :: Maybe [Int], -- for associated families: for each
+ -- tyvar in the AT decl, gives the
+ -- position of that tyvar in the class
+ -- argument list (starting from 0).
+ -- NB: Length is less than tyConArity
+ -- if higher kind signature.
+
algTcSelIds :: [Id], -- Its record selectors (empty if none)
algTcGadtSyntax :: Bool, -- True <=> the data type was declared using GADT syntax
}
| SynTyCon {
- tyConUnique :: Unique,
- tyConName :: Name,
- tyConKind :: Kind,
- tyConArity :: Arity,
-
- tyConTyVars :: [TyVar], -- Bound tyvars
- synTcRhs :: SynTyConRhs -- Expanded type in here
+ tyConUnique :: Unique,
+ tyConName :: Name,
+ tyConKind :: Kind,
+ tyConArity :: Arity,
+
+ tyConTyVars :: [TyVar], -- Bound tyvars
+
+ tyConArgPoss :: Maybe [Int], -- for associated families: for each
+ -- tyvar in the AT decl, gives the
+ -- position of that tyvar in the class
+ -- argument list (starting from 0).
+ -- NB: Length is less than tyConArity
+ -- if higher kind signature.
+
+ synTcRhs :: SynTyConRhs -- Expanded type in here
}
| PrimTyCon { -- Primitive types; cannot be defined in Haskell
tyConName :: Name
}
-type KindCon = TyCon
-
-type SuperKindCon = TyCon
-
type FieldLabel = Name
data AlgTyConRhs
visibleDataCons (DataTyCon{ data_cons = cs }) = cs
visibleDataCons (NewTyCon{ data_con = c }) = [c]
-data AlgTyConParent = NoParentTyCon -- ordinary data type
- | ClassTyCon Class -- class dictionary
- | FamilyTyCon TyCon -- instance of type family
+-- Both type classes as well as data/newtype family instances imply implicit
+-- type constructors. These implicit type constructors refer to their parent
+-- structure (ie, the class or family from which they derive) using a type of
+-- the following form.
+--
+data AlgTyConParent = -- An ordinary type constructor has no parent.
+ NoParentTyCon
+
+ -- Type constructors representing a class dictionary.
+ | ClassTyCon Class
+
+ -- Type constructors representing an instances of a type
+ -- family.
+ | FamilyTyCon TyCon -- the type family
+ [Type] -- instance types
+ TyCon -- a *coercion* identifying
+ -- the representation type
+ -- with the type instance
data SynTyConRhs
= OpenSynTyCon Kind -- Type family: *result* kind given
tyConKind = kind,
tyConArity = length tyvars,
tyConTyVars = tyvars,
+ tyConArgPoss = Nothing,
algTcStupidTheta = stupid,
algTcRhs = rhs,
algTcSelIds = sel_ids,
tyConKind = kind,
tyConArity = length tyvars,
tyConTyVars = tyvars,
+ tyConArgPoss = Nothing,
synTcRhs = rhs
}
OpenNewTyCon -> False
NewTyCon {} -> False
AbstractTyCon -> pprPanic "isDataTyCon" (ppr tc)
-
isDataTyCon (TupleTyCon {tyConBoxed = boxity}) = isBoxed boxity
isDataTyCon other = False
isNewTyCon :: TyCon -> Bool
-isNewTyCon (AlgTyCon {algTcRhs = NewTyCon {}}) = True
-isNewTyCon other = False
+isNewTyCon (AlgTyCon {algTcRhs = rhs}) = case rhs of
+ OpenNewTyCon -> True
+ NewTyCon {} -> True
+ _ -> False
+isNewTyCon other = False
+
+-- This is an important refinement as typical newtype optimisations do *not*
+-- hold for newtype families. Why? Given a type `T a', if T is a newtype
+-- family, there is no unique right hand side by which `T a' can be replaced
+-- by a cast.
+--
+isClosedNewTyCon :: TyCon -> Bool
+isClosedNewTyCon tycon = isNewTyCon tycon && not (isOpenTyCon tycon)
isProductTyCon :: TyCon -> Bool
-- A "product" tycon
isOpenTyCon (AlgTyCon {algTcRhs = OpenNewTyCon }) = True
isOpenTyCon _ = False
+assocTyConArgPoss_maybe :: TyCon -> Maybe [Int]
+assocTyConArgPoss_maybe (AlgTyCon { tyConArgPoss = poss }) = poss
+assocTyConArgPoss_maybe (SynTyCon { tyConArgPoss = poss }) = poss
+assocTyConArgPoss_maybe _ = Nothing
+
+isTyConAssoc :: TyCon -> Bool
+isTyConAssoc = isJust . assocTyConArgPoss_maybe
+
+setTyConArgPoss :: TyCon -> [Int] -> TyCon
+setTyConArgPoss tc@(AlgTyCon {}) poss = tc { tyConArgPoss = Just poss }
+setTyConArgPoss tc@(SynTyCon {}) poss = tc { tyConArgPoss = Just poss }
+setTyConArgPoss tc _ = pprPanic "setTyConArgPoss" (ppr tc)
+
isTupleTyCon :: TyCon -> Bool
-- The unit tycon didn't used to be classed as a tuple tycon
-- but I thought that was silly so I've undone it
newTyConRep (AlgTyCon {tyConTyVars = tvs, algTcRhs = NewTyCon { nt_rep = rep }}) = (tvs, rep)
newTyConRep tycon = pprPanic "newTyConRep" (ppr tycon)
-newTyConCo :: TyCon -> Maybe TyCon
-newTyConCo (AlgTyCon {tyConTyVars = tvs, algTcRhs = NewTyCon { nt_co = co }}) = co
-newTyConCo tycon = pprPanic "newTyConCo" (ppr tycon)
+newTyConCo_maybe :: TyCon -> Maybe TyCon
+newTyConCo_maybe (AlgTyCon {algTcRhs = NewTyCon { nt_co = co }}) = co
+newTyConCo_maybe _ = Nothing
tyConPrimRep :: TyCon -> PrimRep
tyConPrimRep (PrimTyCon {primTyConRep = rep}) = rep
tyConClass_maybe ther_tycon = Nothing
isFamInstTyCon :: TyCon -> Bool
-isFamInstTyCon (AlgTyCon {algTcParent = FamilyTyCon _}) = True
-isFamInstTyCon other_tycon = False
-
-tyConFamily_maybe :: TyCon -> Maybe TyCon
-tyConFamily_maybe (AlgTyCon {algTcParent = FamilyTyCon fam}) = Just fam
-tyConFamily_maybe ther_tycon = Nothing
+isFamInstTyCon (AlgTyCon {algTcParent = FamilyTyCon _ _ _ }) = True
+isFamInstTyCon other_tycon = False
+
+tyConFamInst_maybe :: TyCon -> Maybe (TyCon, [Type])
+tyConFamInst_maybe (AlgTyCon {algTcParent = FamilyTyCon fam instTys _}) =
+ Just (fam, instTys)
+tyConFamInst_maybe ther_tycon =
+ Nothing
+
+tyConFamilyCoercion_maybe :: TyCon -> Maybe TyCon
+tyConFamilyCoercion_maybe (AlgTyCon {algTcParent = FamilyTyCon _ _ coe}) =
+ Just coe
+tyConFamilyCoercion_maybe ther_tycon =
+ Nothing
\end{code}