{- (c) The AQUA Project, Glasgow University, 1994-1998 Wired-in knowledge about primitive types -} {-# LANGUAGE CPP #-} {-# OPTIONS_GHC -Wno-incomplete-uni-patterns #-} -- | This module defines TyCons that can't be expressed in Haskell. -- They are all, therefore, wired-in TyCons. C.f module "GHC.Builtin.Types" module GHC.Builtin.Types.Prim( mkTemplateKindVar, mkTemplateKindVars, mkTemplateTyVars, mkTemplateTyVarsFrom, mkTemplateKiTyVars, mkTemplateKiTyVar, mkTemplateTyConBinders, mkTemplateKindTyConBinders, mkTemplateAnonTyConBinders, alphaTyVars, alphaTyVar, betaTyVar, gammaTyVar, deltaTyVar, alphaTyVarSpec, betaTyVarSpec, gammaTyVarSpec, deltaTyVarSpec, alphaTys, alphaTy, betaTy, gammaTy, deltaTy, alphaTyVarsUnliftedRep, alphaTyVarUnliftedRep, alphaTysUnliftedRep, alphaTyUnliftedRep, runtimeRep1TyVar, runtimeRep2TyVar, runtimeRep3TyVar, runtimeRep1TyVarInf, runtimeRep2TyVarInf, runtimeRep1Ty, runtimeRep2Ty, runtimeRep3Ty, levity1TyVar, levity2TyVar, levity1TyVarInf, levity2TyVarInf, levity1Ty, levity2Ty, alphaConstraintTyVar, alphaConstraintTy, openAlphaTyVar, openBetaTyVar, openGammaTyVar, openAlphaTyVarSpec, openBetaTyVarSpec, openGammaTyVarSpec, openAlphaTy, openBetaTy, openGammaTy, levPolyAlphaTyVar, levPolyBetaTyVar, levPolyAlphaTyVarSpec, levPolyBetaTyVarSpec, levPolyAlphaTy, levPolyBetaTy, multiplicityTyVar1, multiplicityTyVar2, -- Kind constructors... tYPETyCon, tYPETyConName, tYPEKind, cONSTRAINTTyCon, cONSTRAINTTyConName, cONSTRAINTKind, -- Arrows funTyFlagTyCon, isArrowTyCon, fUNTyCon, fUNTyConName, ctArrowTyCon, ctArrowTyConName, ccArrowTyCon, ccArrowTyConName, tcArrowTyCon, tcArrowTyConName, unexposedPrimTyCons, exposedPrimTyCons, primTyCons, charPrimTyCon, charPrimTy, charPrimTyConName, intPrimTyCon, intPrimTy, intPrimTyConName, wordPrimTyCon, wordPrimTy, wordPrimTyConName, addrPrimTyCon, addrPrimTy, addrPrimTyConName, floatPrimTyCon, floatPrimTy, floatPrimTyConName, doublePrimTyCon, doublePrimTy, doublePrimTyConName, statePrimTyCon, mkStatePrimTy, realWorldTyCon, realWorldTy, realWorldStatePrimTy, proxyPrimTyCon, mkProxyPrimTy, arrayPrimTyCon, mkArrayPrimTy, byteArrayPrimTyCon, byteArrayPrimTy, smallArrayPrimTyCon, mkSmallArrayPrimTy, mutableArrayPrimTyCon, mkMutableArrayPrimTy, mutableByteArrayPrimTyCon, mkMutableByteArrayPrimTy, smallMutableArrayPrimTyCon, mkSmallMutableArrayPrimTy, mutVarPrimTyCon, mkMutVarPrimTy, mVarPrimTyCon, mkMVarPrimTy, ioPortPrimTyCon, mkIOPortPrimTy, tVarPrimTyCon, mkTVarPrimTy, stablePtrPrimTyCon, mkStablePtrPrimTy, stableNamePrimTyCon, mkStableNamePrimTy, compactPrimTyCon, compactPrimTy, bcoPrimTyCon, bcoPrimTy, weakPrimTyCon, mkWeakPrimTy, threadIdPrimTyCon, threadIdPrimTy, stackSnapshotPrimTyCon, stackSnapshotPrimTy, promptTagPrimTyCon, mkPromptTagPrimTy, int8PrimTyCon, int8PrimTy, int8PrimTyConName, word8PrimTyCon, word8PrimTy, word8PrimTyConName, int16PrimTyCon, int16PrimTy, int16PrimTyConName, word16PrimTyCon, word16PrimTy, word16PrimTyConName, int32PrimTyCon, int32PrimTy, int32PrimTyConName, word32PrimTyCon, word32PrimTy, word32PrimTyConName, int64PrimTyCon, int64PrimTy, int64PrimTyConName, word64PrimTyCon, word64PrimTy, word64PrimTyConName, eqPrimTyCon, -- ty1 ~# ty2 eqReprPrimTyCon, -- ty1 ~R# ty2 (at role Representational) eqPhantPrimTyCon, -- ty1 ~P# ty2 (at role Phantom) equalityTyCon, -- * SIMD #include "primop-vector-tys-exports.hs-incl" ) where import GHC.Prelude import {-# SOURCE #-} GHC.Builtin.Types ( runtimeRepTy, levityTy, unboxedTupleKind, liftedTypeKind, unliftedTypeKind , boxedRepDataConTyCon, vecRepDataConTyCon , liftedRepTy, unliftedRepTy, zeroBitRepTy , intRepDataConTy , int8RepDataConTy, int16RepDataConTy, int32RepDataConTy, int64RepDataConTy , wordRepDataConTy , word16RepDataConTy, word8RepDataConTy, word32RepDataConTy, word64RepDataConTy , addrRepDataConTy , floatRepDataConTy, doubleRepDataConTy , vec2DataConTy, vec4DataConTy, vec8DataConTy, vec16DataConTy, vec32DataConTy , vec64DataConTy , int8ElemRepDataConTy, int16ElemRepDataConTy, int32ElemRepDataConTy , int64ElemRepDataConTy, word8ElemRepDataConTy, word16ElemRepDataConTy , word32ElemRepDataConTy, word64ElemRepDataConTy, floatElemRepDataConTy , doubleElemRepDataConTy , multiplicityTy , constraintKind ) import {-# SOURCE #-} GHC.Types.TyThing( mkATyCon ) import {-# SOURCE #-} GHC.Core.Type ( mkTyConApp, getLevity ) import GHC.Core.TyCon import GHC.Core.TyCo.Rep -- Doesn't need special access, but this is easier to avoid -- import loops which show up if you import Type instead import GHC.Types.Var ( TyVarBinder, TyVar,binderVar, binderVars , mkTyVar, mkTyVarBinder, mkTyVarBinders ) import GHC.Types.Name import GHC.Types.SrcLoc import GHC.Types.Unique import GHC.Builtin.Uniques import GHC.Builtin.Names import GHC.Utils.Misc ( changeLast ) import GHC.Utils.Panic ( assertPpr ) import GHC.Utils.Outputable import GHC.Data.FastString import Data.Char {- ********************************************************************* * * Building blocks * * ********************************************************************* -} mk_TYPE_app :: Type -> Type mk_TYPE_app rep = mkTyConApp tYPETyCon [rep] mk_CONSTRAINT_app :: Type -> Type mk_CONSTRAINT_app rep = mkTyConApp cONSTRAINTTyCon [rep] mkPrimTc :: FastString -> Unique -> TyCon -> Name mkPrimTc = mkGenPrimTc UserSyntax mkBuiltInPrimTc :: FastString -> Unique -> TyCon -> Name mkBuiltInPrimTc = mkGenPrimTc BuiltInSyntax mkGenPrimTc :: BuiltInSyntax -> FastString -> Unique -> TyCon -> Name mkGenPrimTc built_in_syntax occ key tycon = mkWiredInName gHC_PRIM (mkTcOccFS occ) key (mkATyCon tycon) built_in_syntax -- | Create a primitive 'TyCon' with the given 'Name', -- arguments of kind 'Type` with the given 'Role's, -- and the given result kind representation. -- -- Only use this in "GHC.Builtin.Types.Prim". pcPrimTyCon :: Name -> [Role] -> RuntimeRepType -> TyCon pcPrimTyCon name roles res_rep = mkPrimTyCon name binders result_kind roles where bndr_kis = liftedTypeKind <$ roles binders = mkTemplateAnonTyConBinders bndr_kis result_kind = mk_TYPE_app res_rep -- | Create a primitive nullary 'TyCon' with the given 'Name' -- and result kind representation. -- -- Only use this in "GHC.Builtin.Types.Prim". pcPrimTyCon0 :: Name -> RuntimeRepType -> TyCon pcPrimTyCon0 name res_rep = pcPrimTyCon name [] res_rep -- | Create a primitive 'TyCon' like 'pcPrimTyCon', except the last -- argument is levity-polymorphic, where the levity argument is -- implicit and comes before other arguments -- -- Only use this in "GHC.Builtin.Types.Prim". pcPrimTyCon_LevPolyLastArg :: Name -> [Role] -- ^ roles of the arguments (must be non-empty), -- not including the implicit argument of kind 'Levity', -- which always has 'Nominal' role -> RuntimeRepType -- ^ representation of the fully-applied type -> TyCon pcPrimTyCon_LevPolyLastArg name roles res_rep = mkPrimTyCon name binders result_kind (Nominal : roles) where result_kind = mk_TYPE_app res_rep lev_bndr = mkNamedTyConBinder Inferred levity1TyVar binders = lev_bndr : mkTemplateAnonTyConBinders anon_bndr_kis lev_tv = mkTyVarTy (binderVar lev_bndr) -- [ Type, ..., Type, TYPE (BoxedRep l) ] anon_bndr_kis = changeLast (liftedTypeKind <$ roles) $ mk_TYPE_app $ mkTyConApp boxedRepDataConTyCon [lev_tv] {- ********************************************************************* * * Primitive type constructors * * ********************************************************************* -} {- Note Note [Unexposed TyCons] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ A few primitive TyCons are "unexposed", meaning: * We don't want users to be able to write them (see #15209); i.e. they aren't in scope, ever. In particular they do not appear in the exports of GHC.Prim: see GHC.Builtin.Utils.ghcPrimExports * We don't want users to see them in GHCi's @:browse@ output (see #12023). -} primTyCons :: [TyCon] primTyCons = unexposedPrimTyCons ++ exposedPrimTyCons -- | Primitive 'TyCon's that are defined in GHC.Prim but not "exposed". -- See Note [Unexposed TyCons] unexposedPrimTyCons :: [TyCon] unexposedPrimTyCons = [ eqPrimTyCon -- (~#) , eqReprPrimTyCon -- (~R#) , eqPhantPrimTyCon -- (~P#) -- These arrows are un-exposed for now , ctArrowTyCon -- (=>) , ccArrowTyCon -- (==>) , tcArrowTyCon -- (-=>) ] -- | Primitive 'TyCon's that are defined in, and exported from, GHC.Prim. exposedPrimTyCons :: [TyCon] exposedPrimTyCons = [ addrPrimTyCon , arrayPrimTyCon , byteArrayPrimTyCon , smallArrayPrimTyCon , charPrimTyCon , doublePrimTyCon , floatPrimTyCon , intPrimTyCon , int8PrimTyCon , int16PrimTyCon , int32PrimTyCon , int64PrimTyCon , bcoPrimTyCon , weakPrimTyCon , mutableArrayPrimTyCon , mutableByteArrayPrimTyCon , smallMutableArrayPrimTyCon , mVarPrimTyCon , ioPortPrimTyCon , tVarPrimTyCon , mutVarPrimTyCon , realWorldTyCon , stablePtrPrimTyCon , stableNamePrimTyCon , compactPrimTyCon , statePrimTyCon , proxyPrimTyCon , threadIdPrimTyCon , wordPrimTyCon , word8PrimTyCon , word16PrimTyCon , word32PrimTyCon , word64PrimTyCon , stackSnapshotPrimTyCon , promptTagPrimTyCon , fUNTyCon , tYPETyCon , cONSTRAINTTyCon #include "primop-vector-tycons.hs-incl" ] charPrimTyConName, intPrimTyConName, int8PrimTyConName, int16PrimTyConName, int32PrimTyConName, int64PrimTyConName, wordPrimTyConName, word32PrimTyConName, word8PrimTyConName, word16PrimTyConName, word64PrimTyConName, addrPrimTyConName, floatPrimTyConName, doublePrimTyConName, statePrimTyConName, proxyPrimTyConName, realWorldTyConName, arrayPrimTyConName, smallArrayPrimTyConName, byteArrayPrimTyConName, mutableArrayPrimTyConName, mutableByteArrayPrimTyConName, smallMutableArrayPrimTyConName, mutVarPrimTyConName, mVarPrimTyConName, ioPortPrimTyConName, tVarPrimTyConName, stablePtrPrimTyConName, stableNamePrimTyConName, compactPrimTyConName, bcoPrimTyConName, weakPrimTyConName, threadIdPrimTyConName, eqPrimTyConName, eqReprPrimTyConName, eqPhantPrimTyConName, stackSnapshotPrimTyConName, promptTagPrimTyConName :: Name charPrimTyConName = mkPrimTc (fsLit "Char#") charPrimTyConKey charPrimTyCon intPrimTyConName = mkPrimTc (fsLit "Int#") intPrimTyConKey intPrimTyCon int8PrimTyConName = mkPrimTc (fsLit "Int8#") int8PrimTyConKey int8PrimTyCon int16PrimTyConName = mkPrimTc (fsLit "Int16#") int16PrimTyConKey int16PrimTyCon int32PrimTyConName = mkPrimTc (fsLit "Int32#") int32PrimTyConKey int32PrimTyCon int64PrimTyConName = mkPrimTc (fsLit "Int64#") int64PrimTyConKey int64PrimTyCon wordPrimTyConName = mkPrimTc (fsLit "Word#") wordPrimTyConKey wordPrimTyCon word8PrimTyConName = mkPrimTc (fsLit "Word8#") word8PrimTyConKey word8PrimTyCon word16PrimTyConName = mkPrimTc (fsLit "Word16#") word16PrimTyConKey word16PrimTyCon word32PrimTyConName = mkPrimTc (fsLit "Word32#") word32PrimTyConKey word32PrimTyCon word64PrimTyConName = mkPrimTc (fsLit "Word64#") word64PrimTyConKey word64PrimTyCon addrPrimTyConName = mkPrimTc (fsLit "Addr#") addrPrimTyConKey addrPrimTyCon floatPrimTyConName = mkPrimTc (fsLit "Float#") floatPrimTyConKey floatPrimTyCon doublePrimTyConName = mkPrimTc (fsLit "Double#") doublePrimTyConKey doublePrimTyCon statePrimTyConName = mkPrimTc (fsLit "State#") statePrimTyConKey statePrimTyCon proxyPrimTyConName = mkPrimTc (fsLit "Proxy#") proxyPrimTyConKey proxyPrimTyCon eqPrimTyConName = mkPrimTc (fsLit "~#") eqPrimTyConKey eqPrimTyCon eqReprPrimTyConName = mkBuiltInPrimTc (fsLit "~R#") eqReprPrimTyConKey eqReprPrimTyCon eqPhantPrimTyConName = mkBuiltInPrimTc (fsLit "~P#") eqPhantPrimTyConKey eqPhantPrimTyCon realWorldTyConName = mkPrimTc (fsLit "RealWorld") realWorldTyConKey realWorldTyCon arrayPrimTyConName = mkPrimTc (fsLit "Array#") arrayPrimTyConKey arrayPrimTyCon byteArrayPrimTyConName = mkPrimTc (fsLit "ByteArray#") byteArrayPrimTyConKey byteArrayPrimTyCon smallArrayPrimTyConName = mkPrimTc (fsLit "SmallArray#") smallArrayPrimTyConKey smallArrayPrimTyCon mutableArrayPrimTyConName = mkPrimTc (fsLit "MutableArray#") mutableArrayPrimTyConKey mutableArrayPrimTyCon mutableByteArrayPrimTyConName = mkPrimTc (fsLit "MutableByteArray#") mutableByteArrayPrimTyConKey mutableByteArrayPrimTyCon smallMutableArrayPrimTyConName= mkPrimTc (fsLit "SmallMutableArray#") smallMutableArrayPrimTyConKey smallMutableArrayPrimTyCon mutVarPrimTyConName = mkPrimTc (fsLit "MutVar#") mutVarPrimTyConKey mutVarPrimTyCon ioPortPrimTyConName = mkPrimTc (fsLit "IOPort#") ioPortPrimTyConKey ioPortPrimTyCon mVarPrimTyConName = mkPrimTc (fsLit "MVar#") mVarPrimTyConKey mVarPrimTyCon tVarPrimTyConName = mkPrimTc (fsLit "TVar#") tVarPrimTyConKey tVarPrimTyCon stablePtrPrimTyConName = mkPrimTc (fsLit "StablePtr#") stablePtrPrimTyConKey stablePtrPrimTyCon stableNamePrimTyConName = mkPrimTc (fsLit "StableName#") stableNamePrimTyConKey stableNamePrimTyCon compactPrimTyConName = mkPrimTc (fsLit "Compact#") compactPrimTyConKey compactPrimTyCon stackSnapshotPrimTyConName = mkPrimTc (fsLit "StackSnapshot#") stackSnapshotPrimTyConKey stackSnapshotPrimTyCon bcoPrimTyConName = mkPrimTc (fsLit "BCO") bcoPrimTyConKey bcoPrimTyCon weakPrimTyConName = mkPrimTc (fsLit "Weak#") weakPrimTyConKey weakPrimTyCon threadIdPrimTyConName = mkPrimTc (fsLit "ThreadId#") threadIdPrimTyConKey threadIdPrimTyCon promptTagPrimTyConName = mkPrimTc (fsLit "PromptTag#") promptTagPrimTyConKey promptTagPrimTyCon {- ********************************************************************* * * Type variables * * ********************************************************************* -} {- alphaTyVars is a list of type variables for use in templates: ["a", "b", ..., "z", "t1", "t2", ... ] -} mkTemplateKindVar :: Kind -> TyVar mkTemplateKindVar = mkTyVar (mk_tv_name 0 "k") mkTemplateKindVars :: [Kind] -> [TyVar] -- k0 with unique (mkAlphaTyVarUnique 0) -- k1 with unique (mkAlphaTyVarUnique 1) -- ... etc mkTemplateKindVars [kind] = [mkTemplateKindVar kind] -- Special case for one kind: just "k" mkTemplateKindVars kinds = [ mkTyVar (mk_tv_name u ('k' : show u)) kind | (kind, u) <- kinds `zip` [0..] ] mk_tv_name :: Int -> String -> Name mk_tv_name u s = mkInternalName (mkAlphaTyVarUnique u) (mkTyVarOccFS (mkFastString s)) noSrcSpan mkTemplateTyVarsFrom :: Int -> [Kind] -> [TyVar] -- a with unique (mkAlphaTyVarUnique n) -- b with unique (mkAlphaTyVarUnique n+1) -- ... etc -- Typically called as -- mkTemplateTyVarsFrom (length kv_bndrs) kinds -- where kv_bndrs are the kind-level binders of a TyCon mkTemplateTyVarsFrom n kinds = [ mkTyVar name kind | (kind, index) <- zip kinds [0..], let ch_ord = index + ord 'a' name_str | ch_ord <= ord 'z' = [chr ch_ord] | otherwise = 't':show index name = mk_tv_name (index + n) name_str ] mkTemplateTyVars :: [Kind] -> [TyVar] mkTemplateTyVars = mkTemplateTyVarsFrom 1 mkTemplateTyConBinders :: [Kind] -- [k1, .., kn] Kinds of kind-forall'd vars -> ([Kind] -> [Kind]) -- Arg is [kv1:k1, ..., kvn:kn] -- same length as first arg -- Result is anon arg kinds -> [TyConBinder] mkTemplateTyConBinders kind_var_kinds mk_anon_arg_kinds = kv_bndrs ++ tv_bndrs where kv_bndrs = mkTemplateKindTyConBinders kind_var_kinds anon_kinds = mk_anon_arg_kinds (mkTyVarTys (binderVars kv_bndrs)) tv_bndrs = mkTemplateAnonTyConBindersFrom (length kv_bndrs) anon_kinds mkTemplateKiTyVars :: [Kind] -- [k1, .., kn] Kinds of kind-forall'd vars -> ([Kind] -> [Kind]) -- Arg is [kv1:k1, ..., kvn:kn] -- same length as first arg -- Result is anon arg kinds [ak1, .., akm] -> [TyVar] -- [kv1:k1, ..., kvn:kn, av1:ak1, ..., avm:akm] -- Example: if you want the tyvars for -- forall (r:RuntimeRep) (a:TYPE r) (b:*). blah -- call mkTemplateKiTyVars [RuntimeRep] (\[r] -> [TYPE r, *]) mkTemplateKiTyVars kind_var_kinds mk_arg_kinds = kv_bndrs ++ tv_bndrs where kv_bndrs = mkTemplateKindVars kind_var_kinds anon_kinds = mk_arg_kinds (mkTyVarTys kv_bndrs) tv_bndrs = mkTemplateTyVarsFrom (length kv_bndrs) anon_kinds mkTemplateKiTyVar :: Kind -- [k1, .., kn] Kind of kind-forall'd var -> (Kind -> [Kind]) -- Arg is kv1:k1 -- Result is anon arg kinds [ak1, .., akm] -> [TyVar] -- [kv1:k1, ..., kvn:kn, av1:ak1, ..., avm:akm] -- Example: if you want the tyvars for -- forall (r:RuntimeRep) (a:TYPE r) (b:*). blah -- call mkTemplateKiTyVar RuntimeRep (\r -> [TYPE r, *]) mkTemplateKiTyVar kind mk_arg_kinds = kv_bndr : tv_bndrs where kv_bndr = mkTemplateKindVar kind anon_kinds = mk_arg_kinds (mkTyVarTy kv_bndr) tv_bndrs = mkTemplateTyVarsFrom 1 anon_kinds mkTemplateKindTyConBinders :: [Kind] -> [TyConBinder] -- Makes named, Specified binders mkTemplateKindTyConBinders kinds = [mkNamedTyConBinder Specified tv | tv <- mkTemplateKindVars kinds] mkTemplateAnonTyConBinders :: [Kind] -> [TyConBinder] mkTemplateAnonTyConBinders kinds = mkAnonTyConBinders (mkTemplateTyVars kinds) mkTemplateAnonTyConBindersFrom :: Int -> [Kind] -> [TyConBinder] mkTemplateAnonTyConBindersFrom n kinds = mkAnonTyConBinders (mkTemplateTyVarsFrom n kinds) alphaTyVars :: [TyVar] alphaTyVars = mkTemplateTyVars $ repeat liftedTypeKind alphaTyVar, betaTyVar, gammaTyVar, deltaTyVar :: TyVar (alphaTyVar:betaTyVar:gammaTyVar:deltaTyVar:_) = alphaTyVars alphaTyVarSpec, betaTyVarSpec, gammaTyVarSpec, deltaTyVarSpec :: TyVarBinder (alphaTyVarSpec:betaTyVarSpec:gammaTyVarSpec:deltaTyVarSpec:_) = mkTyVarBinders Specified alphaTyVars alphaConstraintTyVars :: [TyVar] alphaConstraintTyVars = mkTemplateTyVars $ repeat constraintKind alphaConstraintTyVar :: TyVar (alphaConstraintTyVar:_) = alphaConstraintTyVars alphaConstraintTy :: Type alphaConstraintTy = mkTyVarTy alphaConstraintTyVar alphaTys :: [Type] alphaTys = mkTyVarTys alphaTyVars alphaTy, betaTy, gammaTy, deltaTy :: Type (alphaTy:betaTy:gammaTy:deltaTy:_) = alphaTys alphaTyVarsUnliftedRep :: [TyVar] alphaTyVarsUnliftedRep = mkTemplateTyVars $ repeat unliftedTypeKind alphaTyVarUnliftedRep :: TyVar (alphaTyVarUnliftedRep:_) = alphaTyVarsUnliftedRep alphaTysUnliftedRep :: [Type] alphaTysUnliftedRep = mkTyVarTys alphaTyVarsUnliftedRep alphaTyUnliftedRep :: Type (alphaTyUnliftedRep:_) = alphaTysUnliftedRep runtimeRep1TyVar, runtimeRep2TyVar, runtimeRep3TyVar :: TyVar (runtimeRep1TyVar : runtimeRep2TyVar : runtimeRep3TyVar : _) = drop 16 (mkTemplateTyVars (repeat runtimeRepTy)) -- selects 'q','r' runtimeRep1TyVarInf, runtimeRep2TyVarInf :: TyVarBinder runtimeRep1TyVarInf = mkTyVarBinder Inferred runtimeRep1TyVar runtimeRep2TyVarInf = mkTyVarBinder Inferred runtimeRep2TyVar runtimeRep1Ty, runtimeRep2Ty, runtimeRep3Ty :: RuntimeRepType runtimeRep1Ty = mkTyVarTy runtimeRep1TyVar runtimeRep2Ty = mkTyVarTy runtimeRep2TyVar runtimeRep3Ty = mkTyVarTy runtimeRep3TyVar openAlphaTyVar, openBetaTyVar, openGammaTyVar :: TyVar -- alpha :: TYPE r1 -- beta :: TYPE r2 -- gamma :: TYPE r3 [openAlphaTyVar,openBetaTyVar,openGammaTyVar] = mkTemplateTyVars [ mk_TYPE_app runtimeRep1Ty , mk_TYPE_app runtimeRep2Ty , mk_TYPE_app runtimeRep3Ty] openAlphaTyVarSpec, openBetaTyVarSpec, openGammaTyVarSpec :: TyVarBinder openAlphaTyVarSpec = mkTyVarBinder Specified openAlphaTyVar openBetaTyVarSpec = mkTyVarBinder Specified openBetaTyVar openGammaTyVarSpec = mkTyVarBinder Specified openGammaTyVar openAlphaTy, openBetaTy, openGammaTy :: Type openAlphaTy = mkTyVarTy openAlphaTyVar openBetaTy = mkTyVarTy openBetaTyVar openGammaTy = mkTyVarTy openGammaTyVar levity1TyVar, levity2TyVar :: TyVar (levity2TyVar : levity1TyVar : _) -- NB: levity2TyVar before levity1TyVar = drop 10 (mkTemplateTyVars (repeat levityTy)) -- selects 'k', 'l' -- The ordering of levity2TyVar before levity1TyVar is chosen so that -- the more common levity1TyVar uses the levity variable 'l'. levity1TyVarInf, levity2TyVarInf :: TyVarBinder levity1TyVarInf = mkTyVarBinder Inferred levity1TyVar levity2TyVarInf = mkTyVarBinder Inferred levity2TyVar levity1Ty, levity2Ty :: Type levity1Ty = mkTyVarTy levity1TyVar levity2Ty = mkTyVarTy levity2TyVar levPolyAlphaTyVar, levPolyBetaTyVar :: TyVar [levPolyAlphaTyVar, levPolyBetaTyVar] = mkTemplateTyVars [ mk_TYPE_app (mkTyConApp boxedRepDataConTyCon [levity1Ty]) , mk_TYPE_app (mkTyConApp boxedRepDataConTyCon [levity2Ty])] -- alpha :: TYPE ('BoxedRep l) -- beta :: TYPE ('BoxedRep k) levPolyAlphaTyVarSpec, levPolyBetaTyVarSpec :: TyVarBinder levPolyAlphaTyVarSpec = mkTyVarBinder Specified levPolyAlphaTyVar levPolyBetaTyVarSpec = mkTyVarBinder Specified levPolyBetaTyVar levPolyAlphaTy, levPolyBetaTy :: Type levPolyAlphaTy = mkTyVarTy levPolyAlphaTyVar levPolyBetaTy = mkTyVarTy levPolyBetaTyVar multiplicityTyVar1, multiplicityTyVar2 :: TyVar (multiplicityTyVar1 : multiplicityTyVar2 : _) = drop 13 (mkTemplateTyVars (repeat multiplicityTy)) -- selects 'n', 'm' {- ************************************************************************ * * FunTyCon * * ************************************************************************ -} {- Note [Function type constructors and FunTy] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ We have four distinct function type constructors, and a type synonym FUN :: forall (m :: Multiplicity) -> forall {rep1 :: RuntimeRep} {rep2 :: RuntimeRep}. TYPE rep1 -> TYPE rep2 -> Type (=>) :: forall {rep1 :: RuntimeRep} {rep2 :: RuntimeRep}. CONSTRAINT rep1 -> TYPE rep2 -> Type (==>) :: forall {rep1 :: RuntimeRep} {rep2 :: RuntimeRep}. CONSTRAINT rep1 -> CONSTRAINT rep2 -> Constraint (-=>) :: forall {rep1 :: RuntimeRep} {rep2 :: RuntimeRep}. TYPE rep1 -> CONSTRAINT rep2 -> Constraint type (->) = FUN Many For efficiency, all four are always represented by FunTy { ft_af :: FunTyFlag, ft_mult :: Mult , ft_arg :: Type, ft_res :: Type } rather than by using a TyConApp. * The four TyCons FUN, (=>), (==>), (-=>) are all wired in. But (->) is just a regular synonym, with no special treatment; in particular it is not wired-in. * The ft_af :: FunTyFlag distinguishes the four cases. See Note [FunTyFlag] in GHC.Types.Var. * The ft_af field is redundant: it can always be gleaned from the kinds of ft_arg and ft_res. See Note [FunTyFlag] in GHC.Types.Var. * The ft_mult :: Mult field gives the first argument for FUN For the other three cases ft_mult is redundant; it is always Many. Note that of the four type constructors, only `FUN` takes a Multiplicity. * Functions in GHC.Core.Type help to build and decompose `FunTy`. * funTyConAppTy_maybe * funTyFlagTyCon * tyConAppFun_maybe * splitFunTy_maybe Use them! -} funTyFlagTyCon :: FunTyFlag -> TyCon -- `anonArgTyCon af` gets the TyCon that corresponds to the `FunTyFlag` -- But be careful: fUNTyCon has a different kind to the others! -- See Note [Function type constructors and FunTy] funTyFlagTyCon FTF_T_T = fUNTyCon funTyFlagTyCon FTF_T_C = tcArrowTyCon funTyFlagTyCon FTF_C_T = ctArrowTyCon funTyFlagTyCon FTF_C_C = ccArrowTyCon isArrowTyCon :: TyCon -> Bool -- We don't bother to look for plain (->), because this function -- should only be used after unwrapping synonyms isArrowTyCon tc = assertPpr (not (isTypeSynonymTyCon tc)) (ppr tc) getUnique tc `elem` [fUNTyConKey, ctArrowTyConKey, ccArrowTyConKey, tcArrowTyConKey] fUNTyConName, ctArrowTyConName, ccArrowTyConName, tcArrowTyConName :: Name fUNTyConName = mkPrimTc (fsLit "FUN") fUNTyConKey fUNTyCon ctArrowTyConName = mkBuiltInPrimTc (fsLit "=>") ctArrowTyConKey ctArrowTyCon ccArrowTyConName = mkBuiltInPrimTc (fsLit "==>") ccArrowTyConKey ccArrowTyCon tcArrowTyConName = mkBuiltInPrimTc (fsLit "-=>") tcArrowTyConKey tcArrowTyCon -- | The @FUN@ type constructor. -- -- @ -- FUN :: forall (m :: Multiplicity) -> -- forall {rep1 :: RuntimeRep} {rep2 :: RuntimeRep}. -- TYPE rep1 -> TYPE rep2 -> Type -- @ -- -- The runtime representations quantification is left inferred. This -- means they cannot be specified with @-XTypeApplications@. -- -- This is a deliberate choice to allow future extensions to the -- function arrow. fUNTyCon :: TyCon fUNTyCon = mkPrimTyCon fUNTyConName tc_bndrs liftedTypeKind tc_roles where -- See also unrestrictedFunTyCon tc_bndrs = [ mkNamedTyConBinder Required multiplicityTyVar1 , mkNamedTyConBinder Inferred runtimeRep1TyVar , mkNamedTyConBinder Inferred runtimeRep2TyVar ] ++ mkTemplateAnonTyConBinders [ mk_TYPE_app runtimeRep1Ty , mk_TYPE_app runtimeRep2Ty ] tc_roles = [Nominal, Nominal, Nominal, Representational, Representational] -- (=>) :: forall {rep1 :: RuntimeRep} {rep2 :: RuntimeRep}. -- CONSTRAINT rep1 -> TYPE rep2 -> Type ctArrowTyCon :: TyCon ctArrowTyCon = mkPrimTyCon ctArrowTyConName tc_bndrs liftedTypeKind tc_roles where -- See also unrestrictedFunTyCon tc_bndrs = [ mkNamedTyConBinder Inferred runtimeRep1TyVar , mkNamedTyConBinder Inferred runtimeRep2TyVar ] ++ mkTemplateAnonTyConBinders [ mk_CONSTRAINT_app runtimeRep1Ty , mk_TYPE_app runtimeRep2Ty ] tc_roles = [Nominal, Nominal, Representational, Representational] -- (==>) :: forall {rep1 :: RuntimeRep} {rep2 :: RuntimeRep}. -- CONSTRAINT rep1 -> CONSTRAINT rep2 -> Constraint ccArrowTyCon :: TyCon ccArrowTyCon = mkPrimTyCon ccArrowTyConName tc_bndrs constraintKind tc_roles where -- See also unrestrictedFunTyCon tc_bndrs = [ mkNamedTyConBinder Inferred runtimeRep1TyVar , mkNamedTyConBinder Inferred runtimeRep2TyVar ] ++ mkTemplateAnonTyConBinders [ mk_CONSTRAINT_app runtimeRep1Ty , mk_CONSTRAINT_app runtimeRep2Ty ] tc_roles = [Nominal, Nominal, Representational, Representational] -- (-=>) :: forall {rep1 :: RuntimeRep} {rep2 :: RuntimeRep}. -- TYPE rep1 -> CONSTRAINT rep2 -> Constraint tcArrowTyCon :: TyCon tcArrowTyCon = mkPrimTyCon tcArrowTyConName tc_bndrs constraintKind tc_roles where -- See also unrestrictedFunTyCon tc_bndrs = [ mkNamedTyConBinder Inferred runtimeRep1TyVar , mkNamedTyConBinder Inferred runtimeRep2TyVar ] ++ mkTemplateAnonTyConBinders [ mk_TYPE_app runtimeRep1Ty , mk_CONSTRAINT_app runtimeRep2Ty ] tc_roles = [Nominal, Nominal, Representational, Representational] {- ************************************************************************ * * Type and Constraint * * ************************************************************************ Note [TYPE and CONSTRAINT] aka Note [Type vs Constraint] ~~~~~~~~~~~~~~~~~~~~~~~~~~ GHC distinguishes Type from Constraint throughout the compiler. See GHC Proposal #518, and tickets #21623 and #11715. All types that classify values have a kind of the form (TYPE rr) or (CONSTRAINT rr) where the `RuntimeRep` parameter, rr, tells us how the value is represented at runtime. TYPE and CONSTRAINT are primitive type constructors. See Note [RuntimeRep polymorphism] about the `rr` parameter. There are a bunch of type synonyms and data types defined in the library ghc-prim:GHC.Types. All of them are also wired in to GHC, in GHC.Builtin.Types type Constraint = CONSTRAINT LiftedRep :: Type type Type = TYPE LiftedRep :: Type type UnliftedType = TYPE UnliftedRep :: Type type LiftedRep = BoxedRep Lifted :: RuntimeRep type UnliftedRep = BoxedRep Unlifted :: RuntimeRep data RuntimeRep -- Defined in ghc-prim:GHC.Types = BoxedRep Levity | IntRep | FloatRep .. etc .. data Levity = Lifted | Unlifted We abbreviate '*' specially (with -XStarIsType), as if we had this: type * = Type So for example: Int :: TYPE (BoxedRep Lifted) Array# Int :: TYPE (BoxedRep Unlifted) Int# :: TYPE IntRep Float# :: TYPE FloatRep Maybe :: TYPE (BoxedRep Lifted) -> TYPE (BoxedRep Lifted) (# , #) :: TYPE r1 -> TYPE r2 -> TYPE (TupleRep [r1, r2]) Eq Int :: CONSTRAINT (BoxedRep Lifted) IP "foo" Int :: CONSTRAINT (BoxedRep Lifted) a ~ b :: CONSTRAINT (BoxedRep Lifted) a ~# b :: CONSTRAINT (TupleRep []) Constraints are mostly lifted, but unlifted ones are useful too. Specifically (a ~# b) :: CONSTRAINT (TupleRep []) Wrinkles (W1) Type and Constraint are considered distinct throughout GHC. But they are not /apart/: see Note [Type and Constraint are not apart] (W2) We need two absent-error Ids, aBSENT_ERROR_ID for types of kind Type, and aBSENT_CONSTRAINT_ERROR_ID for vaues of kind Constraint. Ditto noInlineId vs noInlineConstraintId in GHC.Types.Id.Make; see Note [inlineId magic]. (W3) We need a TypeOrConstraint flag in LitRubbish. (W4) In the CPR transformation, we can't unbox constructors with constraint arguments because unboxed tuples (# …, … #) currently only supports fields of type TYPE rr. See (CPR2) in Note [Which types are unboxed?] in GHC.Core.Opt.WorkWrap.Utils. Note [Type and Constraint are not apart] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Type and Constraint are not equal (eqType) but they are not /apart/ either. Reason (c.f. #7451): * We want to allow newtype classes, where class C a where { op :: a -> a } * The axiom for such a class will look like axiom axC a :: (C a :: Constraint) ~# (a->a :: Type) * This axiom connects a type of kind Type with one of kind Constraint That is dangerous: kindCo (axC Int) :: Type ~N Constraint And /that/ is bad because we could have type family F a where F Type = Int F Constraint = Bool So now we can prove Int ~N Bool, and all is lost. We prevent this by saying that Type and Constraint are not Apart, which makes the above type family instances illegal. So we ensure that Type and Constraint are not apart; or, more precisely, that TYPE and CONSTRAINT are not apart. This non-apart-ness check is implemented in GHC.Core.Unify.unify_ty: look for `maybeApart MARTypeVsConstraint`. Note that, as before, nothing prevents writing instances like: instance C (Proxy @Type a) where ... In particular, TYPE and CONSTRAINT (and the synonyms Type, Constraint etc) are all allowed in instance heads. It's just that TYPE is not apart from CONSTRAINT, which means that the above instance would irretrievably overlap with: instance C (Proxy @Constraint a) where ... Wrinkles (W1) In GHC.Core.RoughMap.roughMatchTyConName we are careful to map TYPE and CONSTRAINT to the same rough-map key. Reason: If we insert (F @Constraint tys) into a FamInstEnv, and look up (F @Type tys'), we /must/ ensure that the (C @Constraint tys) appears among the unifiables when we do the lookupRM' in GHC.Core.FamInstEnv.lookup_fam_inst_env'. So for the RoughMap we simply pretend that they are the same type constructor. If we don't, we'll treat them as fully apart, which is unsound. (W2) We must extend this treatment to the different arrow types (see Note [Function type constructors and FunTy]): if we have FunCo (axC Int) :: (C Int => Int) ~ ((Int -> Int) -> Int), then we could extract an equality between (=>) and (->). We thus must ensure that (=>) and (->) (among the other arrow combinations) are not Apart. See the FunTy/FunTy case in GHC.Core.Unify.unify_ty. (W3) Are (TYPE IntRep) and (CONSTRAINT WordRep) apart? In truth yes, they are. But it's easier to say that htey are not apart, by reporting "maybeApart" (which is always safe), rather than recurse into the arguments (whose kinds may be utterly different) to look for apartness inside them. Again this is in GHC.Core.Unify.unify_ty. (W4) We give a different Typeable instance for Type than for Constraint. For type classes instances (unlike type family instances) it is not /unsound/ for Type and Constraint to treated as fully distinct; and for Typeable is desirable to give them different TypeReps. Certainly, - both Type and Constraint must /have/ a TypeRep, and - they had better not be the same (else eqTypeRep would give us a proof Type ~N Constraint, which we do not want So in GHC.Tc.Instance.Class.matchTypeable, Type and Constraint are treated as separate TyCons; i.e. given no special treatment. Note [RuntimeRep polymorphism] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Generally speaking, you can't be polymorphic in `RuntimeRep`. E.g f :: forall (rr:RuntimeRep) (a:TYPE rr). a -> [a] f = /\(rr:RuntimeRep) (a:rr) \(a:rr). ... This is no good: we could not generate code for 'f', because the calling convention for 'f' varies depending on whether the argument is a a Int, Int#, or Float#. (You could imagine generating specialised code, one for each instantiation of 'rr', but we don't do that.) Certain functions CAN be runtime-rep-polymorphic, because the code generator never has to manipulate a value of type 'a :: TYPE rr'. * error :: forall (rr:RuntimeRep) (a:TYPE rr). String -> a Code generator never has to manipulate the return value. * unsafeCoerce#, defined in Desugar.mkUnsafeCoercePair: Always inlined to be a no-op unsafeCoerce# :: forall (r1 :: RuntimeRep) (r2 :: RuntimeRep) (a :: TYPE r1) (b :: TYPE r2). a -> b * Unboxed tuples, and unboxed sums, defined in GHC.Builtin.Types Always inlined, and hence specialised to the call site (#,#) :: forall (r1 :: RuntimeRep) (r2 :: RuntimeRep) (a :: TYPE r1) (b :: TYPE r2). a -> b -> TYPE ('TupleRep '[r1, r2]) -} ---------------------- tYPETyCon :: TyCon tYPETyCon = mkPrimTyCon tYPETyConName (mkTemplateAnonTyConBinders [runtimeRepTy]) liftedTypeKind [Nominal] tYPETyConName :: Name tYPETyConName = mkPrimTc (fsLit "TYPE") tYPETyConKey tYPETyCon tYPEKind :: Type tYPEKind = mkTyConTy tYPETyCon ---------------------- cONSTRAINTTyCon :: TyCon cONSTRAINTTyCon = mkPrimTyCon cONSTRAINTTyConName (mkTemplateAnonTyConBinders [runtimeRepTy]) liftedTypeKind [Nominal] cONSTRAINTTyConName :: Name cONSTRAINTTyConName = mkPrimTc (fsLit "CONSTRAINT") cONSTRAINTTyConKey cONSTRAINTTyCon cONSTRAINTKind :: Type cONSTRAINTKind = mkTyConTy cONSTRAINTTyCon {- ********************************************************************* * * Basic primitive types (Char#, Int#, etc.) * * ********************************************************************* -} charPrimTy :: Type charPrimTy = mkTyConTy charPrimTyCon charPrimTyCon :: TyCon charPrimTyCon = pcPrimTyCon0 charPrimTyConName wordRepDataConTy intPrimTy :: Type intPrimTy = mkTyConTy intPrimTyCon intPrimTyCon :: TyCon intPrimTyCon = pcPrimTyCon0 intPrimTyConName intRepDataConTy int8PrimTy :: Type int8PrimTy = mkTyConTy int8PrimTyCon int8PrimTyCon :: TyCon int8PrimTyCon = pcPrimTyCon0 int8PrimTyConName int8RepDataConTy int16PrimTy :: Type int16PrimTy = mkTyConTy int16PrimTyCon int16PrimTyCon :: TyCon int16PrimTyCon = pcPrimTyCon0 int16PrimTyConName int16RepDataConTy int32PrimTy :: Type int32PrimTy = mkTyConTy int32PrimTyCon int32PrimTyCon :: TyCon int32PrimTyCon = pcPrimTyCon0 int32PrimTyConName int32RepDataConTy int64PrimTy :: Type int64PrimTy = mkTyConTy int64PrimTyCon int64PrimTyCon :: TyCon int64PrimTyCon = pcPrimTyCon0 int64PrimTyConName int64RepDataConTy wordPrimTy :: Type wordPrimTy = mkTyConTy wordPrimTyCon wordPrimTyCon :: TyCon wordPrimTyCon = pcPrimTyCon0 wordPrimTyConName wordRepDataConTy word8PrimTy :: Type word8PrimTy = mkTyConTy word8PrimTyCon word8PrimTyCon :: TyCon word8PrimTyCon = pcPrimTyCon0 word8PrimTyConName word8RepDataConTy word16PrimTy :: Type word16PrimTy = mkTyConTy word16PrimTyCon word16PrimTyCon :: TyCon word16PrimTyCon = pcPrimTyCon0 word16PrimTyConName word16RepDataConTy word32PrimTy :: Type word32PrimTy = mkTyConTy word32PrimTyCon word32PrimTyCon :: TyCon word32PrimTyCon = pcPrimTyCon0 word32PrimTyConName word32RepDataConTy word64PrimTy :: Type word64PrimTy = mkTyConTy word64PrimTyCon word64PrimTyCon :: TyCon word64PrimTyCon = pcPrimTyCon0 word64PrimTyConName word64RepDataConTy addrPrimTy :: Type addrPrimTy = mkTyConTy addrPrimTyCon addrPrimTyCon :: TyCon addrPrimTyCon = pcPrimTyCon0 addrPrimTyConName addrRepDataConTy floatPrimTy :: Type floatPrimTy = mkTyConTy floatPrimTyCon floatPrimTyCon :: TyCon floatPrimTyCon = pcPrimTyCon0 floatPrimTyConName floatRepDataConTy doublePrimTy :: Type doublePrimTy = mkTyConTy doublePrimTyCon doublePrimTyCon :: TyCon doublePrimTyCon = pcPrimTyCon0 doublePrimTyConName doubleRepDataConTy {- ************************************************************************ * * The @State#@ type (and @_RealWorld@ types) * * ************************************************************************ Note [The equality types story] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ GHC sports a veritable menagerie of equality types: Type or Lifted? Hetero? Role Built in Defining module class? L/U TyCon ----------------------------------------------------------------------------------------- ~# T U hetero nominal eqPrimTyCon GHC.Prim ~~ C L hetero nominal heqTyCon GHC.Types ~ C L homo nominal eqTyCon GHC.Types :~: T L homo nominal (not built-in) Data.Type.Equality :~~: T L hetero nominal (not built-in) Data.Type.Equality ~R# T U hetero repr eqReprPrimTy GHC.Prim Coercible C L homo repr coercibleTyCon GHC.Types Coercion T L homo repr (not built-in) Data.Type.Coercion ~P# T U hetero phantom eqPhantPrimTyCon GHC.Prim Recall that "hetero" means the equality can related types of different kinds. Knowing that (t1 ~# t2) or (t1 ~R# t2) or even that (t1 ~P# t2) also means that (k1 ~# k2), where (t1 :: k1) and (t2 :: k2). To produce less confusion for end users, when not dumping and without -fprint-equality-relations, each of these groups is printed as the bottommost listed equality. That is, (~#) and (~~) are both rendered as (~) in error messages, and (~R#) is rendered as Coercible. Let's take these one at a time: -------------------------- (~#) :: forall k1 k2. k1 -> k2 -> TYPE (TupleRep '[]) -------------------------- This is The Type Of Equality in GHC. It classifies nominal coercions. This type is used in the solver for recording equality constraints. It responds "yes" to Type.isEqPrimPred and classifies as an EqPred in Type.classifyPredType. All wanted constraints of this type are built with coercion holes. (See Note [Coercion holes] in GHC.Core.TyCo.Rep.) But see also Note [Deferred errors for coercion holes] in GHC.Tc.Errors to see how equality constraints are deferred. Within GHC, ~# is called eqPrimTyCon, and it is defined in GHC.Builtin.Types.Prim. -------------------------- (~~) :: forall k1 k2. k1 -> k2 -> Constraint -------------------------- This is (almost) an ordinary class, defined as if by class a ~# b => a ~~ b instance a ~# b => a ~~ b Here's what's unusual about it: * We can't actually declare it that way because we don't have syntax for ~#. And ~# isn't a constraint, so even if we could write it, it wouldn't kind check. * Users cannot write instances of it. * It is "naturally coherent". This means that the solver won't hesitate to solve a goal of type (a ~~ b) even if there is, say (Int ~~ c) in the context. (Normally, it waits to learn more, just in case the given influences what happens next.) See Note [Solving equality classes] in GHC.Tc.Solver.Dict * It always terminates. That is, in the UndecidableInstances checks, we don't worry if a (~~) constraint is too big, as we know that solving equality terminates. On the other hand, this behaves just like any class w.r.t. eager superclass unpacking in the solver. So a lifted equality given quickly becomes an unlifted equality given. This is good, because the solver knows all about unlifted equalities. There is some special-casing in GHC.Tc.Solver.Dict.matchClassInst to pretend that there is an instance of this class, as we can't write the instance in Haskell. Within GHC, ~~ is called heqTyCon, and it is defined in GHC.Builtin.Types. -------------------------- (~) :: forall k. k -> k -> Constraint -------------------------- This is /exactly/ like (~~), except with a homogeneous kind. It is an almost-ordinary class defined as if by class a ~# b => (a :: k) ~ (b :: k) instance a ~# b => a ~ b * All the bullets for (~~) apply * In addition (~) is magical syntax, as ~ is a reserved symbol. It cannot be exported or imported. * The data constructor of the class is "Eq#", not ":C~" Within GHC, ~ is called eqTyCon, and it is defined in GHC.Builtin.Types. Historical note: prior to July 18 (~) was defined as a more-ordinary class with (~~) as a superclass. But that made it special in different ways; and the extra superclass selections to get from (~) to (~#) via (~~) were tiresome. Now it's defined uniformly with (~~) and Coercible; much nicer.) -------------------------- (:~:) :: forall k. k -> k -> * (:~~:) :: forall k1 k2. k1 -> k2 -> * -------------------------- These are perfectly ordinary GADTs, wrapping (~) and (~~) resp. They are not defined within GHC at all. -------------------------- (~R#) :: forall k1 k2. k1 -> k2 -> TYPE (TupleRep '[]) -------------------------- The is the representational analogue of ~#. This is the type of representational equalities that the solver works on. All wanted constraints of this type are built with coercion holes. Within GHC, ~R# is called eqReprPrimTyCon, and it is defined in GHC.Builtin.Types.Prim. -------------------------- Coercible :: forall k. k -> k -> Constraint -------------------------- This is quite like (~~) in the way it's defined and treated within GHC, but it's homogeneous. Homogeneity helps with type inference (as GHC can solve one kind from the other) and, in my (Richard's) estimation, will be more intuitive for users. An alternative design included HCoercible (like (~~)) and Coercible (like (~)). One annoyance was that we want `coerce :: Coercible a b => a -> b`, and we need the type of coerce to be fully wired-in. So the HCoercible/Coercible split required that both types be fully wired-in. Instead of doing this, I just got rid of HCoercible, as I'm not sure who would use it, anyway. Within GHC, Coercible is called coercibleTyCon, and it is defined in GHC.Builtin.Types. -------------------------- Coercion :: forall k. k -> k -> * -------------------------- This is a perfectly ordinary GADT, wrapping Coercible. It is not defined within GHC at all. -------------------------- (~P#) :: forall k1 k2. k1 -> k2 -> TYPE (TupleRep '[]) -------------------------- This is the phantom analogue of ~# and it is barely used at all. (The solver has no idea about this one.) Here is the motivation: data Phant a = MkPhant type role Phant phantom Phant _P :: Phant Int ~P# Phant Bool We just need to have something to put on that last line. You probably don't need to worry about it. Note [The State# TyCon] ~~~~~~~~~~~~~~~~~~~~~~~ State# is the primitive, unlifted type of states. It has one type parameter, thus State# RealWorld or State# s where s is a type variable. The only purpose of the type parameter is to keep different state threads separate. It is represented by nothing at all. The type parameter to State# is intended to keep separate threads separate. Even though this parameter is not used in the definition of State#, it is given role Nominal to enforce its intended use. -} mkStatePrimTy :: Type -> Type mkStatePrimTy ty = TyConApp statePrimTyCon [ty] statePrimTyCon :: TyCon -- See Note [The State# TyCon] statePrimTyCon = pcPrimTyCon statePrimTyConName [Nominal] zeroBitRepTy {- RealWorld is deeply magical. It is *primitive*, but it is not *unlifted* (hence ptrArg). We never manipulate values of type RealWorld; it's only used in the type system, to parameterise State#. -} realWorldTyCon :: TyCon realWorldTyCon = mkPrimTyCon realWorldTyConName [] liftedTypeKind [] realWorldTy :: Type realWorldTy = mkTyConTy realWorldTyCon realWorldStatePrimTy :: Type realWorldStatePrimTy = mkStatePrimTy realWorldTy -- State# RealWorld mkProxyPrimTy :: Type -> Type -> Type mkProxyPrimTy k ty = TyConApp proxyPrimTyCon [k, ty] proxyPrimTyCon :: TyCon proxyPrimTyCon = mkPrimTyCon proxyPrimTyConName binders res_kind [Nominal,Phantom] where -- Kind: forall k. k -> TYPE (TupleRep '[]) binders = mkTemplateTyConBinders [liftedTypeKind] id res_kind = unboxedTupleKind [] {- ********************************************************************* * * Primitive equality constraints See Note [The equality types story] * * ********************************************************************* -} eqPrimTyCon :: TyCon -- The representation type for equality predicates -- See Note [The equality types story] eqPrimTyCon = mkPrimTyCon eqPrimTyConName binders res_kind roles where -- Kind :: forall k1 k2. k1 -> k2 -> CONSTRAINT ZeroBitRep binders = mkTemplateTyConBinders [liftedTypeKind, liftedTypeKind] id res_kind = TyConApp cONSTRAINTTyCon [zeroBitRepTy] roles = [Nominal, Nominal, Nominal, Nominal] -- like eqPrimTyCon, but the type for *Representational* coercions -- this should only ever appear as the type of a covar. Its role is -- interpreted in coercionRole eqReprPrimTyCon :: TyCon -- See Note [The equality types story] eqReprPrimTyCon = mkPrimTyCon eqReprPrimTyConName binders res_kind roles where -- Kind :: forall k1 k2. k1 -> k2 -> CONSTRAINT ZeroBitRep binders = mkTemplateTyConBinders [liftedTypeKind, liftedTypeKind] id res_kind = TyConApp cONSTRAINTTyCon [zeroBitRepTy] roles = [Nominal, Nominal, Representational, Representational] -- like eqPrimTyCon, but the type for *Phantom* coercions. -- This is only used to make higher-order equalities. Nothing -- should ever actually have this type! eqPhantPrimTyCon :: TyCon eqPhantPrimTyCon = mkPrimTyCon eqPhantPrimTyConName binders res_kind roles where -- Kind :: forall k1 k2. k1 -> k2 -> CONSTRAINT ZeroBitRep binders = mkTemplateTyConBinders [liftedTypeKind, liftedTypeKind] id res_kind = TyConApp cONSTRAINTTyCon [zeroBitRepTy] roles = [Nominal, Nominal, Phantom, Phantom] -- | Given a Role, what TyCon is the type of equality predicates at that role? equalityTyCon :: Role -> TyCon equalityTyCon Nominal = eqPrimTyCon equalityTyCon Representational = eqReprPrimTyCon equalityTyCon Phantom = eqPhantPrimTyCon {- ********************************************************************* * * The primitive array types * * ********************************************************************* -} arrayPrimTyCon, mutableArrayPrimTyCon, mutableByteArrayPrimTyCon, byteArrayPrimTyCon, smallArrayPrimTyCon, smallMutableArrayPrimTyCon :: TyCon arrayPrimTyCon = pcPrimTyCon_LevPolyLastArg arrayPrimTyConName [Representational] unliftedRepTy mutableArrayPrimTyCon = pcPrimTyCon_LevPolyLastArg mutableArrayPrimTyConName [Nominal, Representational] unliftedRepTy mutableByteArrayPrimTyCon = pcPrimTyCon mutableByteArrayPrimTyConName [Nominal] unliftedRepTy byteArrayPrimTyCon = pcPrimTyCon0 byteArrayPrimTyConName unliftedRepTy smallArrayPrimTyCon = pcPrimTyCon_LevPolyLastArg smallArrayPrimTyConName [Representational] unliftedRepTy smallMutableArrayPrimTyCon = pcPrimTyCon_LevPolyLastArg smallMutableArrayPrimTyConName [Nominal, Representational] unliftedRepTy mkArrayPrimTy :: Type -> Type mkArrayPrimTy elt = TyConApp arrayPrimTyCon [getLevity elt, elt] byteArrayPrimTy :: Type byteArrayPrimTy = mkTyConTy byteArrayPrimTyCon mkSmallArrayPrimTy :: Type -> Type mkSmallArrayPrimTy elt = TyConApp smallArrayPrimTyCon [getLevity elt, elt] mkMutableArrayPrimTy :: Type -> Type -> Type mkMutableArrayPrimTy s elt = TyConApp mutableArrayPrimTyCon [getLevity elt, s, elt] mkMutableByteArrayPrimTy :: Type -> Type mkMutableByteArrayPrimTy s = TyConApp mutableByteArrayPrimTyCon [s] mkSmallMutableArrayPrimTy :: Type -> Type -> Type mkSmallMutableArrayPrimTy s elt = TyConApp smallMutableArrayPrimTyCon [getLevity elt, s, elt] {- ********************************************************************* * * The mutable variable type * * ********************************************************************* -} mutVarPrimTyCon :: TyCon mutVarPrimTyCon = pcPrimTyCon_LevPolyLastArg mutVarPrimTyConName [Nominal, Representational] unliftedRepTy mkMutVarPrimTy :: Type -> Type -> Type mkMutVarPrimTy s elt = TyConApp mutVarPrimTyCon [getLevity elt, s, elt] {- ************************************************************************ * * \subsection[TysPrim-io-port-var]{The synchronizing I/O Port type} * * ************************************************************************ -} ioPortPrimTyCon :: TyCon ioPortPrimTyCon = pcPrimTyCon_LevPolyLastArg ioPortPrimTyConName [Nominal, Representational] unliftedRepTy mkIOPortPrimTy :: Type -> Type -> Type mkIOPortPrimTy s elt = TyConApp ioPortPrimTyCon [getLevity elt, s, elt] {- ************************************************************************ * * The synchronizing variable type \subsection[TysPrim-synch-var]{The synchronizing variable type} * * ************************************************************************ -} mVarPrimTyCon :: TyCon mVarPrimTyCon = pcPrimTyCon_LevPolyLastArg mVarPrimTyConName [Nominal, Representational] unliftedRepTy mkMVarPrimTy :: Type -> Type -> Type mkMVarPrimTy s elt = TyConApp mVarPrimTyCon [getLevity elt, s, elt] {- ************************************************************************ * * The transactional variable type * * ************************************************************************ -} tVarPrimTyCon :: TyCon tVarPrimTyCon = pcPrimTyCon_LevPolyLastArg tVarPrimTyConName [Nominal, Representational] unliftedRepTy mkTVarPrimTy :: Type -> Type -> Type mkTVarPrimTy s elt = TyConApp tVarPrimTyCon [getLevity elt, s, elt] {- ************************************************************************ * * The stable-pointer type * * ************************************************************************ -} stablePtrPrimTyCon :: TyCon stablePtrPrimTyCon = pcPrimTyCon_LevPolyLastArg stablePtrPrimTyConName [Representational] addrRepDataConTy mkStablePtrPrimTy :: Type -> Type mkStablePtrPrimTy ty = TyConApp stablePtrPrimTyCon [getLevity ty, ty] {- ************************************************************************ * * The stable-name type * * ************************************************************************ -} stableNamePrimTyCon :: TyCon stableNamePrimTyCon = pcPrimTyCon_LevPolyLastArg stableNamePrimTyConName [Phantom] unliftedRepTy mkStableNamePrimTy :: Type -> Type mkStableNamePrimTy ty = TyConApp stableNamePrimTyCon [getLevity ty, ty] {- ************************************************************************ * * The Compact NFData (CNF) type * * ************************************************************************ -} compactPrimTyCon :: TyCon compactPrimTyCon = pcPrimTyCon0 compactPrimTyConName unliftedRepTy compactPrimTy :: Type compactPrimTy = mkTyConTy compactPrimTyCon {- ************************************************************************ * * The @StackSnapshot#@ type * * ************************************************************************ -} stackSnapshotPrimTyCon :: TyCon stackSnapshotPrimTyCon = pcPrimTyCon0 stackSnapshotPrimTyConName unliftedRepTy stackSnapshotPrimTy :: Type stackSnapshotPrimTy = mkTyConTy stackSnapshotPrimTyCon {- ************************************************************************ * * The ``bytecode object'' type * * ************************************************************************ -} -- Unlike most other primitive types, BCO is lifted. This is because in -- general a BCO may be a thunk for the reasons given in Note [Updatable CAF -- BCOs] in GHCi.CreateBCO. bcoPrimTy :: Type bcoPrimTy = mkTyConTy bcoPrimTyCon bcoPrimTyCon :: TyCon bcoPrimTyCon = pcPrimTyCon0 bcoPrimTyConName liftedRepTy {- ************************************************************************ * * The ``weak pointer'' type * * ************************************************************************ -} weakPrimTyCon :: TyCon weakPrimTyCon = pcPrimTyCon_LevPolyLastArg weakPrimTyConName [Representational] unliftedRepTy mkWeakPrimTy :: Type -> Type mkWeakPrimTy v = TyConApp weakPrimTyCon [getLevity v, v] {- ************************************************************************ * * The ``thread id'' type * * ************************************************************************ A thread id is represented by a pointer to the TSO itself, to ensure that they are always unique and we can always find the TSO for a given thread id. However, this has the unfortunate consequence that a ThreadId# for a given thread is treated as a root by the garbage collector and can keep TSOs around for too long. Hence the programmer API for thread manipulation uses a weak pointer to the thread id internally. -} threadIdPrimTy :: Type threadIdPrimTy = mkTyConTy threadIdPrimTyCon threadIdPrimTyCon :: TyCon threadIdPrimTyCon = pcPrimTyCon0 threadIdPrimTyConName unliftedRepTy {- ************************************************************************ * * The ``prompt tag'' type * * ************************************************************************ -} promptTagPrimTyCon :: TyCon promptTagPrimTyCon = pcPrimTyCon promptTagPrimTyConName [Representational] unliftedRepTy mkPromptTagPrimTy :: Type -> Type mkPromptTagPrimTy v = TyConApp promptTagPrimTyCon [v] {- ************************************************************************ * * \subsection{SIMD vector types} * * ************************************************************************ -} #include "primop-vector-tys.hs-incl"