diff options
| -rw-r--r-- | compiler/coreSyn/CoreLint.lhs | 69 | ||||
| -rw-r--r-- | compiler/coreSyn/CoreSubst.lhs | 2 | ||||
| -rw-r--r-- | compiler/ghc.cabal.in | 1 | ||||
| -rw-r--r-- | compiler/hsSyn/Convert.lhs | 1 | ||||
| -rw-r--r-- | compiler/hsSyn/HsTypes.lhs | 1 | ||||
| -rw-r--r-- | compiler/main/GHC.hs | 4 | ||||
| -rw-r--r-- | compiler/main/InteractiveEval.hs | 4 | ||||
| -rw-r--r-- | compiler/parser/Parser.y.pp | 3 | ||||
| -rw-r--r-- | compiler/parser/ParserCore.y | 3 | ||||
| -rw-r--r-- | compiler/prelude/TysPrim.lhs | 1 | ||||
| -rw-r--r-- | compiler/simplCore/Simplify.lhs | 1 | ||||
| -rw-r--r-- | compiler/types/Coercion.lhs | 801 | ||||
| -rw-r--r-- | compiler/types/OptCoercion.lhs | 403 | ||||
| -rw-r--r-- | compiler/types/TyCon.lhs | 107 | ||||
| -rw-r--r-- | compiler/types/Type.lhs | 205 | ||||
| -rw-r--r-- | compiler/types/Unify.lhs | 2 | ||||
| -rw-r--r-- | compiler/utils/Util.lhs | 12 |
17 files changed, 910 insertions, 710 deletions
diff --git a/compiler/coreSyn/CoreLint.lhs b/compiler/coreSyn/CoreLint.lhs index 4893885e6e..ee6541e173 100644 --- a/compiler/coreSyn/CoreLint.lhs +++ b/compiler/coreSyn/CoreLint.lhs @@ -633,10 +633,9 @@ lintCoercion ty@(FunTy ty1 ty2) ; return (FunTy s1 s2, FunTy t1 t2) } lintCoercion ty@(TyConApp tc tys) - | Just (ar, rule) <- isCoercionTyCon_maybe tc + | Just (ar, desc) <- isCoercionTyCon_maybe tc = do { unless (tys `lengthAtLeast` ar) (badCo ty) - ; (s,t) <- rule lintType lintCoercion - True (take ar tys) + ; (s,t) <- lintCoTyConApp ty desc (take ar tys) ; (ss,ts) <- mapAndUnzipM lintCoercion (drop ar tys) ; check_co_app ty (typeKind s) ss ; return (mkAppTys s ss, mkAppTys t ts) } @@ -677,6 +676,70 @@ lintCoercion (ForAllTy tv ty) badCo :: Coercion -> LintM a badCo co = failWithL (hang (ptext (sLit "Ill-kinded coercion term:")) 2 (ppr co)) +--------------- +lintCoTyConApp :: Coercion -> CoTyConDesc -> [Coercion] -> LintM (Type,Type) +-- Always called with correct number of coercion arguments +-- First arg is just for error message +lintCoTyConApp _ CoLeft (co:_) = lintLR fst co +lintCoTyConApp _ CoRight (co:_) = lintLR snd co +lintCoTyConApp _ CoCsel1 (co:_) = lintCsel fstOf3 co +lintCoTyConApp _ CoCsel2 (co:_) = lintCsel sndOf3 co +lintCoTyConApp _ CoCselR (co:_) = lintCsel thirdOf3 co + +lintCoTyConApp _ CoSym (co:_) + = do { (ty1,ty2) <- lintCoercion co + ; return (ty2,ty1) } + +lintCoTyConApp co CoTrans (co1:co2:_) + = do { (ty1a, ty1b) <- lintCoercion co1 + ; (ty2a, ty2b) <- lintCoercion co2 + ; checkL (ty1b `coreEqType` ty2a) + (hang (ptext (sLit "Trans coercion mis-match:") <+> ppr co) + 2 (vcat [ppr ty1a, ppr ty1b, ppr ty2a, ppr ty2b])) + ; return (ty1a, ty2b) } + +lintCoTyConApp _ CoInst (co:arg_ty:_) + = do { co_tys <- lintCoercion co + ; arg_kind <- lintType arg_ty + ; case decompInst_maybe co_tys of + Just ((tv1,tv2), (ty1,ty2)) + | arg_kind `isSubKind` tyVarKind tv1 + -> return (substTyWith [tv1] [arg_ty] ty1, + substTyWith [tv2] [arg_ty] ty2) + | otherwise + -> failWithL (ptext (sLit "Kind mis-match in inst coercion")) + Nothing -> failWithL (ptext (sLit "Bad argument of inst")) } + +lintCoTyConApp _ (CoAxiom { co_ax_tvs = tvs + , co_ax_lhs = lhs_ty, co_ax_rhs = rhs_ty }) cos + = do { (tys1, tys2) <- mapAndUnzipM lintCoercion cos + ; sequence_ (zipWith checkKinds tvs tys1) + ; return (substTyWith tvs tys1 lhs_ty, + substTyWith tvs tys2 rhs_ty) } + +lintCoTyConApp _ CoUnsafe (ty1:ty2:_) + = do { _ <- lintType ty1 + ; _ <- lintType ty2 -- Ignore kinds; it's unsafe! + ; return (ty1,ty2) } + +lintCoTyConApp _ _ _ = panic "lintCoTyConApp" -- Called with wrong number of coercion args + +---------- +lintLR :: (forall a. (a,a)->a) -> Coercion -> LintM (Type,Type) +lintLR sel co + = do { (ty1,ty2) <- lintCoercion co + ; case decompLR_maybe (ty1,ty2) of + Just res -> return (sel res) + Nothing -> failWithL (ptext (sLit "Bad argument of left/right")) } + +---------- +lintCsel :: (forall a. (a,a,a)->a) -> Coercion -> LintM (Type,Type) +lintCsel sel co + = do { (ty1,ty2) <- lintCoercion co + ; case decompCsel_maybe (ty1,ty2) of + Just res -> return (sel res) + Nothing -> failWithL (ptext (sLit "Bad argument of csel")) } + ------------------- lintType :: OutType -> LintM Kind lintType (TyVarTy tv) diff --git a/compiler/coreSyn/CoreSubst.lhs b/compiler/coreSyn/CoreSubst.lhs index 216b6364a4..9f1e20db4d 100644 --- a/compiler/coreSyn/CoreSubst.lhs +++ b/compiler/coreSyn/CoreSubst.lhs @@ -39,7 +39,7 @@ import OccurAnal( occurAnalyseExpr ) import qualified Type import Type ( Type, TvSubst(..), TvSubstEnv ) -import Coercion ( optCoercion ) +import OptCoercion ( optCoercion ) import VarSet import VarEnv import Id diff --git a/compiler/ghc.cabal.in b/compiler/ghc.cabal.in index 8e444a8ea3..f49d8d0e7f 100644 --- a/compiler/ghc.cabal.in +++ b/compiler/ghc.cabal.in @@ -326,6 +326,7 @@ Library HaddockUtils LexCore Lexer + OptCoercion Parser ParserCore ParserCoreUtils diff --git a/compiler/hsSyn/Convert.lhs b/compiler/hsSyn/Convert.lhs index 0ff26917ed..91d1b903f5 100644 --- a/compiler/hsSyn/Convert.lhs +++ b/compiler/hsSyn/Convert.lhs @@ -19,6 +19,7 @@ import qualified OccName import OccName import SrcLoc import Type +import Coercion import TysWiredIn import BasicTypes as Hs import ForeignCall diff --git a/compiler/hsSyn/HsTypes.lhs b/compiler/hsSyn/HsTypes.lhs index 797a8f28ea..4e6e5ab908 100644 --- a/compiler/hsSyn/HsTypes.lhs +++ b/compiler/hsSyn/HsTypes.lhs @@ -33,6 +33,7 @@ module HsTypes ( import {-# SOURCE #-} HsExpr ( HsSplice, pprSplice ) import Type +import Coercion import HsDoc import BasicTypes import SrcLoc diff --git a/compiler/main/GHC.hs b/compiler/main/GHC.hs index 5289f71ef0..c01a43304f 100644 --- a/compiler/main/GHC.hs +++ b/compiler/main/GHC.hs @@ -254,8 +254,8 @@ import NameSet import RdrName import qualified HsSyn -- hack as we want to reexport the whole module import HsSyn hiding ((<.>)) -import Type hiding (typeKind) -import TcType hiding (typeKind) +import Type +import TcType hiding( typeKind ) import Id import Var import TysPrim ( alphaTyVars ) diff --git a/compiler/main/InteractiveEval.hs b/compiler/main/InteractiveEval.hs index 352fbf055f..d4230c7313 100644 --- a/compiler/main/InteractiveEval.hs +++ b/compiler/main/InteractiveEval.hs @@ -42,9 +42,9 @@ module InteractiveEval ( import HscMain hiding (compileExpr) import HscTypes import TcRnDriver -import Type hiding (typeKind) -import TcType hiding (typeKind) import InstEnv +import Type +import TcType hiding( typeKind ) import Var import Id import Name hiding ( varName ) diff --git a/compiler/parser/Parser.y.pp b/compiler/parser/Parser.y.pp index 4cd637fb34..212a79ce36 100644 --- a/compiler/parser/Parser.y.pp +++ b/compiler/parser/Parser.y.pp @@ -45,7 +45,8 @@ import SrcLoc ( Located(..), unLoc, getLoc, noLoc, combineSrcSpans, mkSrcLoc, mkSrcSpan ) import Module import StaticFlags ( opt_SccProfilingOn, opt_Hpc ) -import Type ( Kind, mkArrowKind, liftedTypeKind, unliftedTypeKind ) +import Type ( Kind, liftedTypeKind, unliftedTypeKind ) +import Coercion ( mkArrowKind ) import Class ( FunDep ) import BasicTypes ( Boxity(..), Fixity(..), FixityDirection(..), IPName(..), Activation(..), RuleMatchInfo(..), defaultInlinePragma ) diff --git a/compiler/parser/ParserCore.y b/compiler/parser/ParserCore.y index 6839fa2d45..f43e225041 100644 --- a/compiler/parser/ParserCore.y +++ b/compiler/parser/ParserCore.y @@ -16,8 +16,9 @@ import RdrName import OccName import Type ( Kind, liftedTypeKindTyCon, openTypeKindTyCon, unliftedTypeKindTyCon, - argTypeKindTyCon, ubxTupleKindTyCon, mkArrowKind, mkTyConApp + argTypeKindTyCon, ubxTupleKindTyCon, mkTyConApp ) +import Coercion( mkArrowKind ) import Name( Name, nameOccName, nameModule, mkExternalName ) import Module import ParserCoreUtils diff --git a/compiler/prelude/TysPrim.lhs b/compiler/prelude/TysPrim.lhs index 4e1576f9f0..18c80a456e 100644 --- a/compiler/prelude/TysPrim.lhs +++ b/compiler/prelude/TysPrim.lhs @@ -57,6 +57,7 @@ import OccName ( mkTcOcc ) import OccName ( mkTyVarOccFS, mkTcOccFS ) import TyCon ( TyCon, mkPrimTyCon, mkLiftedPrimTyCon, mkAnyTyCon ) import Type +import Coercion import SrcLoc import Unique ( mkAlphaTyVarUnique ) import PrelNames diff --git a/compiler/simplCore/Simplify.lhs b/compiler/simplCore/Simplify.lhs index 4c1b6cb07b..86eef46b5b 100644 --- a/compiler/simplCore/Simplify.lhs +++ b/compiler/simplCore/Simplify.lhs @@ -20,6 +20,7 @@ import Var import IdInfo import Name ( mkSystemVarName, isExternalName ) import Coercion +import OptCoercion ( optCoercion ) import FamInstEnv ( topNormaliseType ) import DataCon ( DataCon, dataConWorkId, dataConRepStrictness ) import CoreMonad ( SimplifierSwitch(..), Tick(..) ) diff --git a/compiler/types/Coercion.lhs b/compiler/types/Coercion.lhs index 2b0f1b3223..bc93372e0f 100644 --- a/compiler/types/Coercion.lhs +++ b/compiler/types/Coercion.lhs @@ -3,23 +3,32 @@ % \begin{code} --- The above warning supression flag is a temporary kludge. --- While working on this module you are encouraged to remove it and fix --- any warnings in the module. See --- http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings --- for details - --- | Module for type coercions, as used in System FC. See 'CoreSyn.Expr' for +-- | Module for (a) type kinds and (b) type coercions, +-- as used in System FC. See 'CoreSyn.Expr' for -- more on System FC and how coercions fit into it. -- -- Coercions are represented as types, and their kinds tell what types the --- coercion works on. The coercion kind constructor is a special TyCon that must always be saturated, like so: +-- coercion works on. The coercion kind constructor is a special TyCon that +-- must always be saturated, like so: -- --- > typeKind (symCoercion type) :: TyConApp CoercionTyCon{...} [type, type] +-- > typeKind (symCoercion type) :: TyConApp CoTyCon{...} [type, type] module Coercion ( -- * Main data type - Coercion, - + Coercion, Kind, + typeKind, + + -- ** Deconstructing Kinds + kindFunResult, splitKindFunTys, splitKindFunTysN, splitKindFunTy_maybe, + + -- ** Predicates on Kinds + isLiftedTypeKind, isUnliftedTypeKind, isOpenTypeKind, + isUbxTupleKind, isArgTypeKind, isKind, isTySuperKind, + isCoSuperKind, isSuperKind, isCoercionKind, + mkArrowKind, mkArrowKinds, + + isSubArgTypeKind, isSubOpenTypeKind, isSubKind, defaultKind, eqKind, + isSubKindCon, + mkCoKind, mkCoPredTy, coVarKind, coVarKind_maybe, coercionKind, coercionKinds, isIdentityCoercion, @@ -35,7 +44,6 @@ module Coercion ( mkNewTypeCoercion, mkFamInstCoercion, mkAppsCoercion, mkCsel1Coercion, mkCsel2Coercion, mkCselRCoercion, - splitNewTypeRepCo_maybe, instNewTyCon_maybe, decomposeCo, unsafeCoercionTyCon, symCoercionTyCon, transCoercionTyCon, leftCoercionTyCon, @@ -44,9 +52,8 @@ module Coercion ( -- ** Decomposition decompLR_maybe, decompCsel_maybe, decompInst_maybe, - - -- ** Optimisation - optCoercion, + splitCoPredTy_maybe, + splitNewTypeRepCo_maybe, instNewTyCon_maybe, decomposeCo, -- ** Comparison coreEqCoercion, coreEqCoercion2, @@ -73,12 +80,140 @@ import VarEnv import Name import PrelNames import Util -import Control.Monad import BasicTypes -import MonadUtils import Outputable import FastString +\end{code} + +%************************************************************************ +%* * + Functions over Kinds +%* * +%************************************************************************ +\begin{code} +-- | Essentially 'funResultTy' on kinds +kindFunResult :: Kind -> Kind +kindFunResult k = funResultTy k + +-- | Essentially 'splitFunTys' on kinds +splitKindFunTys :: Kind -> ([Kind],Kind) +splitKindFunTys k = splitFunTys k + +splitKindFunTy_maybe :: Kind -> Maybe (Kind,Kind) +splitKindFunTy_maybe = splitFunTy_maybe + +-- | Essentially 'splitFunTysN' on kinds +splitKindFunTysN :: Int -> Kind -> ([Kind],Kind) +splitKindFunTysN k = splitFunTysN k + +-- | See "Type#kind_subtyping" for details of the distinction between these 'Kind's +isUbxTupleKind, isOpenTypeKind, isArgTypeKind, isUnliftedTypeKind :: Kind -> Bool +isOpenTypeKindCon, isUbxTupleKindCon, isArgTypeKindCon, + isUnliftedTypeKindCon, isSubArgTypeKindCon :: TyCon -> Bool + +isOpenTypeKindCon tc = tyConUnique tc == openTypeKindTyConKey + +isOpenTypeKind (TyConApp tc _) = isOpenTypeKindCon tc +isOpenTypeKind _ = False + +isUbxTupleKindCon tc = tyConUnique tc == ubxTupleKindTyConKey + +isUbxTupleKind (TyConApp tc _) = isUbxTupleKindCon tc +isUbxTupleKind _ = False + +isArgTypeKindCon tc = tyConUnique tc == argTypeKindTyConKey + +isArgTypeKind (TyConApp tc _) = isArgTypeKindCon tc +isArgTypeKind _ = False + +isUnliftedTypeKindCon tc = tyConUnique tc == unliftedTypeKindTyConKey + +isUnliftedTypeKind (TyConApp tc _) = isUnliftedTypeKindCon tc +isUnliftedTypeKind _ = False + +isSubOpenTypeKind :: Kind -> Bool +-- ^ True of any sub-kind of OpenTypeKind (i.e. anything except arrow) +isSubOpenTypeKind (FunTy k1 k2) = ASSERT2 ( isKind k1, text "isSubOpenTypeKind" <+> ppr k1 <+> text "::" <+> ppr (typeKind k1) ) + ASSERT2 ( isKind k2, text "isSubOpenTypeKind" <+> ppr k2 <+> text "::" <+> ppr (typeKind k2) ) + False +isSubOpenTypeKind (TyConApp kc []) = ASSERT( isKind (TyConApp kc []) ) True +isSubOpenTypeKind other = ASSERT( isKind other ) False + -- This is a conservative answer + -- It matters in the call to isSubKind in + -- checkExpectedKind. + +isSubArgTypeKindCon kc + | isUnliftedTypeKindCon kc = True + | isLiftedTypeKindCon kc = True + | isArgTypeKindCon kc = True + | otherwise = False + +isSubArgTypeKind :: Kind -> Bool +-- ^ True of any sub-kind of ArgTypeKind +isSubArgTypeKind (TyConApp kc []) = isSubArgTypeKindCon kc +isSubArgTypeKind _ = False + +-- | Is this a super-kind (i.e. a type-of-kinds)? +isSuperKind :: Type -> Bool +isSuperKind (TyConApp (skc) []) = isSuperKindTyCon skc +isSuperKind _ = False + +-- | Is this a kind (i.e. a type-of-types)? +isKind :: Kind -> Bool +isKind k = isSuperKind (typeKind k) + +isSubKind :: Kind -> Kind -> Bool +-- ^ @k1 \`isSubKind\` k2@ checks that @k1@ <: @k2@ +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 _ _ = False + +eqKind :: Kind -> Kind -> Bool +eqKind = tcEqType + +isSubKindCon :: TyCon -> TyCon -> Bool +-- ^ @kc1 \`isSubKindCon\` kc2@ checks that @kc1@ <: @kc2@ +isSubKindCon kc1 kc2 + | isLiftedTypeKindCon kc1 && isLiftedTypeKindCon kc2 = True + | isUnliftedTypeKindCon kc1 && isUnliftedTypeKindCon kc2 = True + | isUbxTupleKindCon kc1 && isUbxTupleKindCon kc2 = True + | isOpenTypeKindCon kc2 = True + -- we already know kc1 is not a fun, its a TyCon + | isArgTypeKindCon kc2 && isSubArgTypeKindCon kc1 = True + | otherwise = False + +defaultKind :: Kind -> Kind +-- ^ Used when generalising: default kind ? and ?? to *. See "Type#kind_subtyping" for more +-- information on what that means + +-- When we generalise, we make generic type variables whose kind is +-- simple (* or *->* etc). So generic type variables (other than +-- built-in constants like 'error') always have simple kinds. This is important; +-- consider +-- f x = True +-- We want f to get type +-- f :: forall (a::*). a -> Bool +-- Not +-- f :: forall (a::??). a -> Bool +-- because that would allow a call like (f 3#) as well as (f True), +--and the calling conventions differ. This defaulting is done in TcMType.zonkTcTyVarBndr. +defaultKind k + | isSubOpenTypeKind k = liftedTypeKind + | isSubArgTypeKind k = liftedTypeKind + | otherwise = k +\end{code} + +%************************************************************************ +%* * + Coercions +%* * +%************************************************************************ + + +\begin{code} -- | A 'Coercion' represents a 'Type' something should be coerced to. type Coercion = Type @@ -154,83 +289,6 @@ getEqPredTys :: PredType -> (Type,Type) getEqPredTys (EqPred ty1 ty2) = (ty1, ty2) getEqPredTys other = pprPanic "getEqPredTys" (ppr other) --- | If it is the case that --- --- > c :: (t1 ~ t2) --- --- i.e. the kind of @c@ is a 'CoercionKind' relating @t1@ and @t2@, then @coercionKind c = (t1, t2)@. -coercionKind :: Coercion -> (Type, Type) -coercionKind ty@(TyVarTy a) | isCoVar a = coVarKind a - | otherwise = (ty, ty) -coercionKind (AppTy ty1 ty2) - = let (s1, t1) = coercionKind ty1 - (s2, t2) = coercionKind ty2 in - (mkAppTy s1 s2, mkAppTy t1 t2) -coercionKind co@(TyConApp tc args) - | Just (ar, rule) <- isCoercionTyCon_maybe tc - -- CoercionTyCons carry their kinding rule, so we use it here - = WARN( not (length args >= ar), ppr co ) -- Always saturated - (let (ty1,ty2) = runID (rule (return . typeKind) - (return . coercionKind) - False (take ar args)) - -- Apply the rule to the right number of args - -- Always succeeds (if term is well-kinded!) - (tys1, tys2) = coercionKinds (drop ar args) - in (mkAppTys ty1 tys1, mkAppTys ty2 tys2)) - - | otherwise - = let (lArgs, rArgs) = coercionKinds args in - (TyConApp tc lArgs, TyConApp tc rArgs) -coercionKind (FunTy ty1 ty2) - = let (t1, t2) = coercionKind ty1 - (s1, s2) = coercionKind ty2 in - (mkFunTy t1 s1, mkFunTy t2 s2) - -coercionKind (ForAllTy tv ty) - | isCoVar tv --- c1 :: s1~s2 c2 :: t1~t2 c3 :: r1~r2 --- ---------------------------------------------- --- c1~c2 => c3 :: (s1~t1) => r1 ~ (s2~t2) => r2 --- or --- forall (_:c1~c2) - = let (c1,c2) = coVarKind tv - (s1,s2) = coercionKind c1 - (t1,t2) = coercionKind c2 - (r1,r2) = coercionKind ty - in - (mkCoPredTy s1 t1 r1, mkCoPredTy s2 t2 r2) - - | otherwise --- c1 :: s1~s2 c2 :: t1~t2 c3 :: r1~r2 --- ---------------------------------------------- --- forall a:k. c :: forall a:k. t1 ~ forall a:k. t2 - = let (ty1, ty2) = coercionKind ty in - (ForAllTy tv ty1, ForAllTy tv ty2) - -coercionKind (PredTy (EqPred c1 c2)) - = pprTrace "coercionKind" (pprEqPred (c1,c2)) $ - let k1 = coercionKindPredTy c1 - k2 = coercionKindPredTy c2 in - (k1,k2) - -- These should not show up in coercions at all - -- becuase they are in the form of for-alls - where - coercionKindPredTy c = let (t1, t2) = coercionKind c in mkCoKind t1 t2 - - - -coercionKind (PredTy (ClassP cl args)) - = let (lArgs, rArgs) = coercionKinds args in - (PredTy (ClassP cl lArgs), PredTy (ClassP cl rArgs)) -coercionKind (PredTy (IParam name ty)) - = let (ty1, ty2) = coercionKind ty in - (PredTy (IParam name ty1), PredTy (IParam name ty2)) - --- | Apply 'coercionKind' to multiple 'Coercion's -coercionKinds :: [Coercion] -> ([Type], [Type]) -coercionKinds tys = unzip $ map coercionKind tys - -------------------------------------- isIdentityCoercion :: Coercion -> Bool isIdentityCoercion co = case coercionKind co of @@ -322,8 +380,7 @@ mkInstsCoercion co tys = foldl mkInstCoercion co tys -- but it is used when we know we are dealing with bottom, which is one case in which -- it is safe. This is also used implement the @unsafeCoerce#@ primitive. mkUnsafeCoercion :: Type -> Type -> Coercion -mkUnsafeCoercion ty1 ty2 - = mkCoercion unsafeCoercionTyCon [ty1, ty2] +mkUnsafeCoercion ty1 ty2 = mkCoercion unsafeCoercionTyCon [ty1, ty2] -- See note [Newtype coercions] in TyCon @@ -334,16 +391,12 @@ mkUnsafeCoercion ty1 ty2 -- a subset of those 'TyVar's. mkNewTypeCoercion :: Name -> TyCon -> [TyVar] -> Type -> TyCon mkNewTypeCoercion name tycon tvs rhs_ty - = mkCoercionTyCon name co_con_arity rule + = mkCoercionTyCon name arity desc where - co_con_arity = length tvs - - rule :: CoTyConKindChecker - rule kc_ty _kc_co checking args - = do { ks <- mapM kc_ty args - ; unless (not checking || kindAppOk (tyConKind tycon) ks) - (fail "Argument kind mis-match") - ; return (TyConApp tycon args, substTyWith tvs args rhs_ty) } + arity = length tvs + desc = CoAxiom { co_ax_tvs = tvs + , co_ax_lhs = mkTyConApp tycon (mkTyVarTys tvs) + , co_ax_rhs = rhs_ty } -- | Create a coercion identifying a @data@, @newtype@ or @type@ representation type -- and its family instance. It has the form @Co tvs :: F ts ~ R tvs@, where @Co@ is @@ -355,26 +408,13 @@ mkFamInstCoercion :: Name -- ^ Unique name for the coercion tycon -> [Type] -- ^ Type instance (@ts@) -> TyCon -- ^ Representation tycon (@R@) -> TyCon -- ^ Coercion tycon (@Co@) -mkFamInstCoercion name tvs family instTys rep_tycon - = mkCoercionTyCon name coArity rule +mkFamInstCoercion name tvs family inst_tys rep_tycon + = mkCoercionTyCon name arity desc where - coArity = length tvs - - rule :: CoTyConKindChecker - rule kc_ty _kc_co checking args - = do { ks <- mapM kc_ty args - ; unless (not checking || kindAppOk (tyConKind rep_tycon) ks) - (fail "Argument kind mis-match") - ; return (substTyWith tvs args $ -- with sigma = [tys/tvs], - TyConApp family instTys -- sigma (F ts) - , TyConApp rep_tycon args) } -- ~ R tys - -kindAppOk :: Kind -> [Kind] -> Bool -kindAppOk _ [] = True -kindAppOk kfn (k:ks) - = case splitKindFunTy_maybe kfn of - Just (kfa, kfb) | k `isSubKind` kfa -> kindAppOk kfb ks - _other -> False + arity = length tvs + desc = CoAxiom { co_ax_tvs = tvs + , co_ax_lhs = mkTyConApp family inst_tys + , co_ax_rhs = mkTyConApp rep_tycon (mkTyVarTys tvs) } \end{code} @@ -403,137 +443,67 @@ symCoercionTyCon, transCoercionTyCon, leftCoercionTyCon, rightCoercionTyCon, instCoercionTyCon, unsafeCoercionTyCon, csel1CoercionTyCon, csel2CoercionTyCon, cselRCoercionTyCon :: TyCon -symCoercionTyCon - = mkCoercionTyCon symCoercionTyConName 1 kc_sym - where - kc_sym :: CoTyConKindChecker - kc_sym _kc_ty kc_co _ (co:_) - = do { (ty1,ty2) <- kc_co co - ; return (ty2,ty1) } - kc_sym _ _ _ _ = panic "kc_sym" - -transCoercionTyCon - = mkCoercionTyCon transCoercionTyConName 2 kc_trans - where - kc_trans :: CoTyConKindChecker - kc_trans _kc_ty kc_co checking (co1:co2:_) - = do { (a1, r1) <- kc_co co1 - ; (a2, r2) <- kc_co co2 - ; unless (not checking || (r1 `coreEqType` a2)) - (fail "Trans coercion mis-match") - ; return (a1, r2) } - kc_trans _ _ _ _ = panic "kc_sym" - ---------------------------------------------------- -leftCoercionTyCon = mkCoercionTyCon leftCoercionTyConName 1 (kcLR_help fst) -rightCoercionTyCon = mkCoercionTyCon rightCoercionTyConName 1 (kcLR_help snd) - -kcLR_help :: (forall a. (a,a)->a) -> CoTyConKindChecker -kcLR_help select _kc_ty kc_co _checking (co : _) - = do { (ty1, ty2) <- kc_co co - ; case decompLR_maybe ty1 ty2 of - Nothing -> fail "decompLR" - Just res -> return (select res) } -kcLR_help _ _ _ _ _ = panic "kcLR_help" - -decompLR_maybe :: Type -> Type -> Maybe ((Type,Type), (Type,Type)) +symCoercionTyCon = mkCoercionTyCon symCoercionTyConName 1 CoSym +transCoercionTyCon = mkCoercionTyCon transCoercionTyConName 2 CoTrans +leftCoercionTyCon = mkCoercionTyCon leftCoercionTyConName 1 CoLeft +rightCoercionTyCon = mkCoercionTyCon rightCoercionTyConName 1 CoRight +instCoercionTyCon = mkCoercionTyCon instCoercionTyConName 2 CoInst +csel1CoercionTyCon = mkCoercionTyCon csel1CoercionTyConName 1 CoCsel1 +csel2CoercionTyCon = mkCoercionTyCon csel2CoercionTyConName 1 CoCsel2 +cselRCoercionTyCon = mkCoercionTyCon cselRCoercionTyConName 1 CoCselR +unsafeCoercionTyCon = mkCoercionTyCon unsafeCoercionTyConName 2 CoUnsafe + +transCoercionTyConName, symCoercionTyConName, leftCoercionTyConName, + rightCoercionTyConName, instCoercionTyConName, unsafeCoercionTyConName, + csel1CoercionTyConName, csel2CoercionTyConName, cselRCoercionTyConName :: Name + +transCoercionTyConName = mkCoConName (fsLit "trans") transCoercionTyConKey transCoercionTyCon +symCoercionTyConName = mkCoConName (fsLit "sym") symCoercionTyConKey symCoercionTyCon +leftCoercionTyConName = mkCoConName (fsLit "left") leftCoercionTyConKey leftCoercionTyCon +rightCoercionTyConName = mkCoConName (fsLit "right") rightCoercionTyConKey rightCoercionTyCon +instCoercionTyConName = mkCoConName (fsLit "inst") instCoercionTyConKey instCoercionTyCon +csel1CoercionTyConName = mkCoConName (fsLit "csel1") csel1CoercionTyConKey csel1CoercionTyCon +csel2CoercionTyConName = mkCoConName (fsLit "csel2") csel2CoercionTyConKey csel2CoercionTyCon +cselRCoercionTyConName = mkCoConName (fsLit "cselR") cselRCoercionTyConKey cselRCoercionTyCon +unsafeCoercionTyConName = mkCoConName (fsLit "CoUnsafe") unsafeCoercionTyConKey unsafeCoercionTyCon + +mkCoConName :: FastString -> Unique -> TyCon -> Name +mkCoConName occ key coCon = mkWiredInName gHC_PRIM (mkTcOccFS occ) + key (ATyCon coCon) BuiltInSyntax +\end{code} + +\begin{code} +------------ +decompLR_maybe :: (Type,Type) -> Maybe ((Type,Type), (Type,Type)) -- Helper for left and right. Finds coercion kind of its input and -- returns the left and right projections of the coercion... -- -- if c :: t1 s1 ~ t2 s2 then splitCoercionKindOf c = ((t1, t2), (s1, s2)) -decompLR_maybe ty1 ty2 +decompLR_maybe (ty1,ty2) | Just (ty_fun1, ty_arg1) <- splitAppTy_maybe ty1 , Just (ty_fun2, ty_arg2) <- splitAppTy_maybe ty2 = Just ((ty_fun1, ty_fun2),(ty_arg1, ty_arg2)) -decompLR_maybe _ _ = Nothing +decompLR_maybe _ = Nothing ---------------------------------------------------- -instCoercionTyCon - = mkCoercionTyCon instCoercionTyConName 2 kcInst_help - where - kcInst_help :: CoTyConKindChecker - kcInst_help kc_ty kc_co checking (co : ty : _) - = do { (t1,t2) <- kc_co co - ; k <- kc_ty ty - ; case decompInst_maybe t1 t2 of - Nothing -> fail "decompInst" - Just ((tv1,tv2), (ty1,ty2)) -> do - { unless (not checking || (k `isSubKind` tyVarKind tv1)) - (fail "Coercion instantation kind mis-match") - ; return (substTyWith [tv1] [ty] ty1, - substTyWith [tv2] [ty] ty2) } } - kcInst_help _ _ _ _ = panic "kcInst_help" - -decompInst_maybe :: Type -> Type -> Maybe ((TyVar,TyVar), (Type,Type)) -decompInst_maybe ty1 ty2 +------------ +decompInst_maybe :: (Type, Type) -> Maybe ((TyVar,TyVar), (Type,Type)) +decompInst_maybe (ty1, ty2) | Just (tv1,r1) <- splitForAllTy_maybe ty1 , Just (tv2,r2) <- splitForAllTy_maybe ty2 = Just ((tv1,tv2), (r1,r2)) -decompInst_maybe _ _ = Nothing +decompInst_maybe _ = Nothing ---------------------------------------------------- -unsafeCoercionTyCon - = mkCoercionTyCon unsafeCoercionTyConName 2 kc_unsafe - where - kc_unsafe kc_ty _kc_co _checking (ty1:ty2:_) - = do { _ <- kc_ty ty1 - ; _ <- kc_ty ty2 - ; return (ty1,ty2) } - kc_unsafe _ _ _ _ = panic "kc_unsafe" - ---------------------------------------------------- --- The csel* family - -csel1CoercionTyCon = mkCoercionTyCon csel1CoercionTyConName 1 (kcCsel_help fstOf3) -csel2CoercionTyCon = mkCoercionTyCon csel2CoercionTyConName 1 (kcCsel_help sndOf3) -cselRCoercionTyCon = mkCoercionTyCon cselRCoercionTyConName 1 (kcCsel_help thirdOf3) - -kcCsel_help :: (forall a. (a,a,a) -> a) -> CoTyConKindChecker -kcCsel_help select _kc_ty kc_co _checking (co : _) - = do { (ty1,ty2) <- kc_co co - ; case decompCsel_maybe ty1 ty2 of - Nothing -> fail "decompCsel" - Just res -> return (select res) } -kcCsel_help _ _ _ _ _ = panic "kcCsel_help" - -decompCsel_maybe :: Type -> Type -> Maybe ((Type,Type), (Type,Type), (Type,Type)) +------------ +decompCsel_maybe :: (Type, Type) -> Maybe ((Type,Type), (Type,Type), (Type,Type)) -- If co :: (s1~t1 => r1) ~ (s2~t2 => r2) -- Then csel1 co :: s1 ~ s2 -- csel2 co :: t1 ~ t2 -- cselR co :: r1 ~ r2 -decompCsel_maybe ty1 ty2 +decompCsel_maybe (ty1, ty2) | Just (s1, t1, r1) <- splitCoPredTy_maybe ty1 , Just (s2, t2, r2) <- splitCoPredTy_maybe ty2 = Just ((s1,s2), (t1,t2), (r1,r2)) -decompCsel_maybe _ _ = Nothing - -fstOf3 :: (a,b,c) -> a -sndOf3 :: (a,b,c) -> b -thirdOf3 :: (a,b,c) -> c -fstOf3 (a,_,_) = a -sndOf3 (_,b,_) = b -thirdOf3 (_,_,c) = c - --------------------------------------- --- Their Names - -transCoercionTyConName, symCoercionTyConName, leftCoercionTyConName, - rightCoercionTyConName, instCoercionTyConName, unsafeCoercionTyConName, - csel1CoercionTyConName, csel2CoercionTyConName, cselRCoercionTyConName :: Name - -transCoercionTyConName = mkCoConName (fsLit "trans") transCoercionTyConKey transCoercionTyCon -symCoercionTyConName = mkCoConName (fsLit "sym") symCoercionTyConKey symCoercionTyCon -leftCoercionTyConName = mkCoConName (fsLit "left") leftCoercionTyConKey leftCoercionTyCon -rightCoercionTyConName = mkCoConName (fsLit "right") rightCoercionTyConKey rightCoercionTyCon -instCoercionTyConName = mkCoConName (fsLit "inst") instCoercionTyConKey instCoercionTyCon -csel1CoercionTyConName = mkCoConName (fsLit "csel1") csel1CoercionTyConKey csel1CoercionTyCon -csel2CoercionTyConName = mkCoConName (fsLit "csel2") csel2CoercionTyConKey csel2CoercionTyCon -cselRCoercionTyConName = mkCoConName (fsLit "cselR") cselRCoercionTyConKey cselRCoercionTyCon -unsafeCoercionTyConName = mkCoConName (fsLit "CoUnsafe") unsafeCoercionTyConKey unsafeCoercionTyCon - -mkCoConName :: FastString -> Unique -> TyCon -> Name -mkCoConName occ key coCon = mkWiredInName gHC_PRIM (mkTcOccFS occ) - key (ATyCon coCon) BuiltInSyntax +decompCsel_maybe _ = Nothing \end{code} @@ -693,233 +663,148 @@ mkEqPredCoI _ (ACo co1) ty2 coi2 = ACo $ PredTy $ EqPred co1 (fromCoI coi \end{code} %************************************************************************ -%* * - Optimising coercions -%* * +%* * + The kind of a type, and of a coercion +%* * %************************************************************************ \begin{code} -optCoercion :: TvSubst -> Coercion -> NormalCo --- ^ optCoercion applies a substitution to a coercion, --- *and* optimises it to reduce its size -optCoercion env co = opt_co env False co - -type NormalCo = Coercion - -- Invariants: - -- * The substitution has been fully applied - -- * For trans coercions (co1 `trans` co2) - -- co1 is not a trans, and neither co1 nor co2 is identity - -- * If the coercion is the identity, it has no CoVars of CoTyCons in it (just types) - -type NormalNonIdCo = NormalCo -- Extra invariant: not the identity - -opt_co, opt_co' :: TvSubst - -> Bool -- True <=> return (sym co) - -> Coercion - -> NormalCo -opt_co = opt_co' --- opt_co sym co = pprTrace "opt_co {" (ppr sym <+> ppr co) $ --- co1 `seq` --- pprTrace "opt_co done }" (ppr co1) --- WARN( not same_co_kind, ppr co <+> dcolon <+> pprEqPred (s1,t1) --- $$ ppr co1 <+> dcolon <+> pprEqPred (s2,t2) ) --- co1 --- where --- co1 = opt_co' sym co --- same_co_kind = s1 `coreEqType` s2 && t1 `coreEqType` t2 --- (s,t) = coercionKind co --- (s1,t1) | sym = (t,s) --- | otherwise = (s,t) --- (s2,t2) = coercionKind co1 - -opt_co' env sym (AppTy ty1 ty2) = mkAppTy (opt_co env sym ty1) (opt_co env sym ty2) -opt_co' env sym (FunTy ty1 ty2) = FunTy (opt_co env sym ty1) (opt_co env sym ty2) -opt_co' env sym (PredTy (ClassP cls tys)) = PredTy (ClassP cls (map (opt_co env sym) tys)) -opt_co' env sym (PredTy (IParam n ty)) = PredTy (IParam n (opt_co env sym ty)) -opt_co' _ _ co@(PredTy (EqPred {})) = pprPanic "optCoercion" (ppr co) - -opt_co' env sym co@(TyVarTy tv) - | Just ty <- lookupTyVar env tv = opt_co' (zapTvSubstEnv env) sym ty - | not (isCoVar tv) = co -- Identity; does not mention a CoVar - | ty1 `coreEqType` ty2 = ty1 -- Identity; ..ditto.. - | not sym = co - | otherwise = mkSymCoercion co - where - (ty1,ty2) = coVarKind tv +typeKind :: Type -> Kind +typeKind ty@(TyConApp tc tys) + | isCoercionTyCon tc = typeKind (fst (coercionKind ty)) + | otherwise = foldr (\_ k -> kindFunResult k) (tyConKind tc) tys + -- During coercion optimisation we *do* match a type + -- against a coercion (see OptCoercion.matchesAxiomLhs) + -- So the use of typeKind in Unify.match_kind must work on coercions too + -- Hence the isCoercionTyCon case above + +typeKind (PredTy pred) = predKind pred +typeKind (AppTy fun _) = kindFunResult (typeKind fun) +typeKind (ForAllTy _ ty) = typeKind ty +typeKind (TyVarTy tyvar) = tyVarKind tyvar +typeKind (FunTy _arg res) + -- Hack alert. The kind of (Int -> Int#) is liftedTypeKind (*), + -- not unliftedTypKind (#) + -- The only things that can be after a function arrow are + -- (a) types (of kind openTypeKind or its sub-kinds) + -- (b) kinds (of super-kind TY) (e.g. * -> (* -> *)) + | isTySuperKind k = k + | otherwise = ASSERT( isSubOpenTypeKind k) liftedTypeKind + where + k = typeKind res + +------------------ +predKind :: PredType -> Kind +predKind (EqPred {}) = coSuperKind -- A coercion kind! +predKind (ClassP {}) = liftedTypeKind -- Class and implicitPredicates are +predKind (IParam {}) = liftedTypeKind -- always represented by lifted types + +------------------ +-- | If it is the case that +-- +-- > c :: (t1 ~ t2) +-- +-- i.e. the kind of @c@ is a 'CoercionKind' relating @t1@ and @t2@, then @coercionKind c = (t1, t2)@. +coercionKind :: Coercion -> (Type, Type) +coercionKind ty@(TyVarTy a) | isCoVar a = coVarKind a + | otherwise = (ty, ty) +coercionKind (AppTy ty1 ty2) + = let (s1, t1) = coercionKind ty1 + (s2, t2) = coercionKind ty2 in + (mkAppTy s1 s2, mkAppTy t1 t2) +coercionKind co@(TyConApp tc args) + | Just (ar, desc) <- isCoercionTyCon_maybe tc + -- CoercionTyCons carry their kinding rule, so we use it here + = WARN( not (length args >= ar), ppr co ) -- Always saturated + (let (ty1, ty2) = coTyConAppKind desc (take ar args) + (tys1, tys2) = coercionKinds (drop ar args) + in (mkAppTys ty1 tys1, mkAppTys ty2 tys2)) -opt_co' env sym (ForAllTy tv cor) - | isCoVar tv = mkCoPredTy (opt_co env sym co1) (opt_co env sym co2) (opt_co env sym cor) - | otherwise = case substTyVarBndr env tv of - (env', tv') -> ForAllTy tv' (opt_co env' sym cor) - where - (co1,co2) = coVarKind tv + | otherwise + = let (lArgs, rArgs) = coercionKinds args in + (TyConApp tc lArgs, TyConApp tc rArgs) + +coercionKind (FunTy ty1 ty2) + = let (t1, t2) = coercionKind ty1 + (s1, s2) = coercionKind ty2 in + (mkFunTy t1 s1, mkFunTy t2 s2) + +coercionKind (ForAllTy tv ty) + | isCoVar tv +-- c1 :: s1~s2 c2 :: t1~t2 c3 :: r1~r2 +-- ---------------------------------------------- +-- c1~c2 => c3 :: (s1~t1) => r1 ~ (s2~t2) => r2 +-- or +-- forall (_:c1~c2) + = let (c1,c2) = coVarKind tv + (s1,s2) = coercionKind c1 + (t1,t2) = coercionKind c2 + (r1,r2) = coercionKind ty + in + (mkCoPredTy s1 t1 r1, mkCoPredTy s2 t2 r2) -opt_co' env sym (TyConApp tc cos) - | isCoercionTyCon tc - = foldl mkAppTy - (opt_co_tc_app env sym tc (take arity cos)) - (map (opt_co env sym) (drop arity cos)) | otherwise - = TyConApp tc (map (opt_co env sym) cos) - where - arity = tyConArity tc - --------- -opt_co_tc_app :: TvSubst -> Bool -> TyCon -> [Coercion] -> NormalCo --- Used for CoercionTyCons only --- Arguments are *not* already simplified/substituted -opt_co_tc_app env sym tc cos - | tc `hasKey` symCoercionTyConKey - = opt_co env (not sym) co1 - - | tc `hasKey` transCoercionTyConKey - = if sym then opt_trans opt_co2 opt_co1 -- sym (g `o` h) = sym h `o` sym g - else opt_trans opt_co1 opt_co2 - - | tc `hasKey` leftCoercionTyConKey - , Just (opt_co1_left, _) <- splitAppTy_maybe opt_co1 - = opt_co1_left -- sym (left g) = left (sym g) - -- The opt_co has the sym pushed into it - - | tc `hasKey` rightCoercionTyConKey - , Just (_, opt_co1_right) <- splitAppTy_maybe opt_co1 - = opt_co1_right - - | tc `hasKey` csel1CoercionTyConKey - , Just (s1,_,_) <- splitCoPredTy_maybe opt_co1 - = s1 - - | tc `hasKey` csel2CoercionTyConKey - , Just (_,s2,_) <- splitCoPredTy_maybe opt_co1 - = s2 - - | tc `hasKey` cselRCoercionTyConKey - , Just (_,_,r) <- splitCoPredTy_maybe opt_co1 - = r - - | tc `hasKey` instCoercionTyConKey -- See if the first arg - -- is already a forall - , Just (tv, co1_body) <- splitForAllTy_maybe co1 - , let ty = substTy env co2 - = opt_co (extendTvSubst env tv ty) sym co1_body - - | tc `hasKey` instCoercionTyConKey -- See if is *now* a forall - , Just (tv, opt_co1_body) <- splitForAllTy_maybe opt_co1 - , let ty = substTy env co2 - = substTyWith [tv] [ty] opt_co1_body -- An inefficient one-variable substitution - - | otherwise -- Do *not* push sym inside top-level axioms - -- e.g. if g is a top-level axiom - -- g a : F a ~ a - -- Then (sym (g ty)) /= g (sym ty) !! - = if sym then mkSymCoercion the_co - else the_co +-- c1 :: s1~s2 c2 :: t1~t2 c3 :: r1~r2 +-- ---------------------------------------------- +-- forall a:k. c :: forall a:k. t1 ~ forall a:k. t2 + = let (ty1, ty2) = coercionKind ty in + (ForAllTy tv ty1, ForAllTy tv ty2) + +coercionKind (PredTy (ClassP cl args)) + = let (lArgs, rArgs) = coercionKinds args in + (PredTy (ClassP cl lArgs), PredTy (ClassP cl rArgs)) +coercionKind (PredTy (IParam name ty)) + = let (ty1, ty2) = coercionKind ty in + (PredTy (IParam name ty1), PredTy (IParam name ty2)) +coercionKind (PredTy (EqPred c1 c2)) + = pprTrace "coercionKind" (pprEqPred (c1,c2)) $ + -- These should not show up in coercions at all + -- becuase they are in the form of for-alls + let k1 = coercionKindPredTy c1 + k2 = coercionKindPredTy c2 in + (k1,k2) where - (co1 : cos1) = cos - (co2 : _) = cos1 - - -- These opt_cos have the sym pushed into them - opt_co1 = opt_co env sym co1 - opt_co2 = opt_co env sym co2 - - -- However the_co does *not* have sym pushed into it - the_co = TyConApp tc (map (opt_co env False) cos) - -------------- -opt_trans :: NormalCo -> NormalCo -> NormalCo -opt_trans co1 co2 - | isIdNormCo co1 = co2 - | otherwise = opt_trans1 co1 co2 - -opt_trans1 :: NormalNonIdCo -> NormalCo -> NormalCo --- First arg is not the identity -opt_trans1 co1 co2 - | isIdNormCo co2 = co1 - | otherwise = opt_trans2 co1 co2 - -opt_trans2 :: NormalNonIdCo -> NormalNonIdCo -> NormalCo --- Neither arg is the identity -opt_trans2 (TyConApp tc [co1a,co1b]) co2 - | tc `hasKey` transCoercionTyConKey - = opt_trans1 co1a (opt_trans2 co1b co2) - -opt_trans2 co1 co2 - | Just co <- opt_trans_rule co1 co2 - = co - -opt_trans2 co1 (TyConApp tc [co2a,co2b]) - | tc `hasKey` transCoercionTyConKey - , Just co1_2a <- opt_trans_rule co1 co2a - = if isIdNormCo co1_2a - then co2b - else opt_trans2 co1_2a co2b - -opt_trans2 co1 co2 - = mkTransCoercion co1 co2 - ------- -opt_trans_rule :: NormalNonIdCo -> NormalNonIdCo -> Maybe NormalCo -opt_trans_rule (TyConApp tc [co1]) co2 - | tc `hasKey` symCoercionTyConKey - , co1 `coreEqType` co2 - , (_,ty2) <- coercionKind co2 - = Just ty2 - -opt_trans_rule co1 (TyConApp tc [co2]) - | tc `hasKey` symCoercionTyConKey - , co1 `coreEqType` co2 - , (ty1,_) <- coercionKind co1 - = Just ty1 - -opt_trans_rule (TyConApp tc1 [co1,ty1]) (TyConApp tc2 [co2,ty2]) - | tc1 `hasKey` instCoercionTyConKey - , tc1 == tc2 - , ty1 `coreEqType` ty2 - = Just (mkInstCoercion (opt_trans2 co1 co2) ty1) - -opt_trans_rule (TyConApp tc1 cos1) (TyConApp tc2 cos2) - | not (isCoercionTyCon tc1) || - getUnique tc1 `elem` [ leftCoercionTyConKey, rightCoercionTyConKey - , csel1CoercionTyConKey, csel2CoercionTyConKey - , cselRCoercionTyConKey ] --Yuk! - , tc1 == tc2 -- Works for left,right, and csel* family - -- BUT NOT equality axioms - -- E.g. (g Int) `trans` (g Bool) - -- /= g (Int . Bool) - = Just (TyConApp tc1 (zipWith opt_trans cos1 cos2)) - -opt_trans_rule co1 co2 - | Just (co1a, co1b) <- splitAppTy_maybe co1 - , Just (co2a, co2b) <- splitAppTy_maybe co2 - = Just (mkAppTy (opt_trans co1a co2a) (opt_trans co1b co2b)) - - | Just (s1,t1,r1) <- splitCoPredTy_maybe co1 - , Just (s2,t2,r2) <- splitCoPredTy_maybe co1 - = Just (mkCoPredTy (opt_trans s1 s2) - (opt_trans t1 t2) - (opt_trans r1 r2)) - - | Just (tv1,r1) <- splitForAllTy_maybe co1 - , Just (tv2,r2) <- splitForAllTy_maybe co2 - , not (isCoVar tv1) -- Both have same kind - , let r2' = substTyWith [tv2] [TyVarTy tv1] r2 - = Just (ForAllTy tv1 (opt_trans2 r1 r2')) - -opt_trans_rule _ _ = Nothing - - -------------- -isIdNormCo :: NormalCo -> Bool --- Cheap identity test: look for coercions with no coercion variables at all --- So it'll return False for (sym g `trans` g) -isIdNormCo ty = go ty + coercionKindPredTy c = let (t1, t2) = coercionKind c in mkCoKind t1 t2 + +------------------ +-- | Apply 'coercionKind' to multiple 'Coercion's +coercionKinds :: [Coercion] -> ([Type], [Type]) +coercionKinds tys = unzip $ map coercionKind tys + +------------------ +-- | 'coTyConAppKind' is given a list of the type arguments to the 'CoTyCon', +-- and constructs the types that the resulting coercion relates. +-- Fails (in the monad) if ill-kinded. +-- Typically the monad is +-- either the Lint monad (with the consistency-check flag = True), +-- or the ID monad with a panic on failure (and the consistency-check flag = False) +coTyConAppKind + :: CoTyConDesc + -> [Type] -- Exactly right number of args + -> (Type, Type) -- Kind of this application +coTyConAppKind CoUnsafe (ty1:ty2:_) + = (ty1,ty2) +coTyConAppKind CoSym (co:_) + | (ty1,ty2) <- coercionKind co = (ty2,ty1) +coTyConAppKind CoTrans (co1:co2:_) + = (fst (coercionKind co1), snd (coercionKind co2)) +coTyConAppKind CoLeft (co:_) + | Just (res,_) <- decompLR_maybe (coercionKind co) = res +coTyConAppKind CoRight (co:_) + | Just (_,res) <- decompLR_maybe (coercionKind co) = res +coTyConAppKind CoCsel1 (co:_) + | Just (res,_,_) <- decompCsel_maybe (coercionKind co) = res +coTyConAppKind CoCsel2 (co:_) + | Just (_,res,_) <- decompCsel_maybe (coercionKind co) = res +coTyConAppKind CoCselR (co:_) + | Just (_,_,res) <- decompCsel_maybe (coercionKind co) = res +coTyConAppKind CoInst (co:ty:_) + | Just ((tv1,tv2), (ty1,ty2)) <- decompInst_maybe (coercionKind co) + = (substTyWith [tv1] [ty] ty1, substTyWith [tv2] [ty] ty2) +coTyConAppKind (CoAxiom { co_ax_tvs = tvs + , co_ax_lhs = lhs_ty, co_ax_rhs = rhs_ty }) cos + = (substTyWith tvs tys1 lhs_ty, substTyWith tvs tys2 rhs_ty) where - go (TyVarTy tv) = not (isCoVar tv) - go (AppTy t1 t2) = go t1 && go t2 - go (FunTy t1 t2) = go t1 && go t2 - go (ForAllTy tv ty) = go (tyVarKind tv) && go ty - go (TyConApp tc tys) = not (isCoercionTyCon tc) && all go tys - go (PredTy (IParam _ ty)) = go ty - go (PredTy (ClassP _ tys)) = all go tys - go (PredTy (EqPred t1 t2)) = go t1 && go t2 -\end{code} + (tys1, tys2) = coercionKinds cos +coTyConAppKind desc cos = pprPanic "coTyConAppKind" (ppr desc $$ ppr cos) +\end{code} diff --git a/compiler/types/OptCoercion.lhs b/compiler/types/OptCoercion.lhs new file mode 100644 index 0000000000..43de7d626e --- /dev/null +++ b/compiler/types/OptCoercion.lhs @@ -0,0 +1,403 @@ +%
+% (c) The University of Glasgow 2006
+%
+
+\begin{code}
+{-# OPTIONS_GHC -w #-}
+module OptCoercion (
+ optCoercion
+ ) where
+
+#include "HsVersions.h"
+
+import Unify ( tcMatchTy )
+import Coercion
+import Type
+import TypeRep
+import TyCon
+import Var
+import VarSet
+import PrelNames
+import Util
+import Outputable
+\end{code}
+
+%************************************************************************
+%* *
+ Optimising coercions
+%* *
+%************************************************************************
+
+\begin{code}
+optCoercion :: TvSubst -> Coercion -> NormalCo
+-- ^ optCoercion applies a substitution to a coercion,
+-- *and* optimises it to reduce its size
+optCoercion env co = opt_co env False co
+
+type NormalCo = Coercion
+ -- Invariants:
+ -- * The substitution has been fully applied
+ -- * For trans coercions (co1 `trans` co2)
+ -- co1 is not a trans, and neither co1 nor co2 is identity
+ -- * If the coercion is the identity, it has no CoVars of CoTyCons in it (just types)
+
+type NormalNonIdCo = NormalCo -- Extra invariant: not the identity
+
+opt_co, opt_co' :: TvSubst
+ -> Bool -- True <=> return (sym co)
+ -> Coercion
+ -> NormalCo
+opt_co = opt_co'
+-- opt_co sym co = pprTrace "opt_co {" (ppr sym <+> ppr co) $
+-- co1 `seq`
+-- pprTrace "opt_co done }" (ppr co1)
+-- WARN( not same_co_kind, ppr co <+> dcolon <+> pprEqPred (s1,t1)
+-- $$ ppr co1 <+> dcolon <+> pprEqPred (s2,t2) )
+-- co1
+-- where
+-- co1 = opt_co' sym co
+-- same_co_kind = s1 `coreEqType` s2 && t1 `coreEqType` t2
+-- (s,t) = coercionKind co
+-- (s1,t1) | sym = (t,s)
+-- | otherwise = (s,t)
+-- (s2,t2) = coercionKind co1
+
+opt_co' env sym (AppTy ty1 ty2) = mkAppTy (opt_co env sym ty1) (opt_co env sym ty2)
+opt_co' env sym (FunTy ty1 ty2) = FunTy (opt_co env sym ty1) (opt_co env sym ty2)
+opt_co' env sym (PredTy (ClassP cls tys)) = PredTy (ClassP cls (map (opt_co env sym) tys))
+opt_co' env sym (PredTy (IParam n ty)) = PredTy (IParam n (opt_co env sym ty))
+opt_co' _ _ co@(PredTy (EqPred {})) = pprPanic "optCoercion" (ppr co)
+
+opt_co' env sym co@(TyVarTy tv)
+ | Just ty <- lookupTyVar env tv = opt_co' (zapTvSubstEnv env) sym ty
+ | not (isCoVar tv) = co -- Identity; does not mention a CoVar
+ | ty1 `coreEqType` ty2 = ty1 -- Identity; ..ditto..
+ | not sym = co
+ | otherwise = mkSymCoercion co
+ where
+ (ty1,ty2) = coVarKind tv
+
+opt_co' env sym (ForAllTy tv cor)
+ | isCoVar tv = mkCoPredTy (opt_co env sym co1) (opt_co env sym co2) (opt_co env sym cor)
+ | otherwise = case substTyVarBndr env tv of
+ (env', tv') -> ForAllTy tv' (opt_co env' sym cor)
+ where
+ (co1,co2) = coVarKind tv
+
+opt_co' env sym (TyConApp tc cos)
+ | Just (arity, desc) <- isCoercionTyCon_maybe tc
+ = mkAppTys (opt_co_tc_app env sym tc desc (take arity cos))
+ (map (opt_co env sym) (drop arity cos))
+ | otherwise
+ = TyConApp tc (map (opt_co env sym) cos)
+
+--------
+opt_co_tc_app :: TvSubst -> Bool -> TyCon -> CoTyConDesc -> [Coercion] -> NormalCo
+-- Used for CoercionTyCons only
+-- Arguments are *not* already simplified/substituted
+opt_co_tc_app env sym tc desc cos
+ = case desc of
+ CoAxiom {} -- Do *not* push sym inside top-level axioms
+ -- e.g. if g is a top-level axiom
+ -- g a : F a ~ a
+ -- Then (sym (g ty)) /= g (sym ty) !!
+ | sym -> mkSymCoercion the_co
+ | otherwise -> the_co
+ where
+ the_co = TyConApp tc (map (opt_co env False) cos)
+ -- Note that the_co does *not* have sym pushed into it
+
+ CoTrans
+ | sym -> opt_trans opt_co2 opt_co1 -- sym (g `o` h) = sym h `o` sym g
+ | otherwise -> opt_trans opt_co1 opt_co2
+
+ CoUnsafe
+ | sym -> TyConApp tc [opt_co2,opt_co1]
+ | otherwise -> TyConApp tc [opt_co1,opt_co2]
+
+ CoSym -> opt_co env (not sym) co1
+ CoLeft -> opt_lr fst
+ CoRight -> opt_lr snd
+ CoCsel1 -> opt_csel fstOf3
+ CoCsel2 -> opt_csel sndOf3
+ CoCselR -> opt_csel thirdOf3
+
+ CoInst -- See if the first arg is already a forall
+ -- ...then we can just extend the current substitution
+ | Just (tv, co1_body) <- splitForAllTy_maybe co1
+ -> opt_co (extendTvSubst env tv ty') sym co1_body
+
+ -- See if is *now* a forall
+ | Just (tv, opt_co1_body) <- splitForAllTy_maybe opt_co1
+ -> substTyWith [tv] [ty'] opt_co1_body -- An inefficient one-variable substitution
+
+ | otherwise
+ -> TyConApp tc [opt_co1, ty']
+ where
+ ty' = substTy env co2
+
+ where
+ (co1 : cos1) = cos
+ (co2 : _) = cos1
+
+ -- These opt_cos have the sym pushed into them
+ opt_co1 = opt_co env sym co1
+ opt_co2 = opt_co env sym co2
+
+ the_unary_opt_co = TyConApp tc [opt_co1]
+
+ opt_lr sel = case splitAppTy_maybe opt_co1 of
+ Nothing -> the_unary_opt_co
+ Just lr -> sel lr
+ opt_csel sel = case splitCoPredTy_maybe opt_co1 of
+ Nothing -> the_unary_opt_co
+ Just lr -> sel lr
+
+-------------
+opt_transL :: [NormalCo] -> [NormalCo] -> [NormalCo]
+opt_transL = zipWith opt_trans
+
+opt_trans :: NormalCo -> NormalCo -> NormalCo
+opt_trans co1 co2
+ | isIdNormCo co1 = co2
+ | otherwise = opt_trans1 co1 co2
+
+opt_trans1 :: NormalNonIdCo -> NormalCo -> NormalCo
+-- First arg is not the identity
+opt_trans1 co1 co2
+ | isIdNormCo co2 = co1
+ | otherwise = opt_trans2 co1 co2
+
+opt_trans2 :: NormalNonIdCo -> NormalNonIdCo -> NormalCo
+-- Neither arg is the identity
+opt_trans2 (TyConApp tc [co1a,co1b]) co2
+ | tc `hasKey` transCoercionTyConKey
+ = opt_trans1 co1a (opt_trans2 co1b co2)
+
+opt_trans2 co1 co2
+ | Just co <- opt_trans_rule co1 co2
+ = co
+
+opt_trans2 co1 (TyConApp tc [co2a,co2b])
+ | tc `hasKey` transCoercionTyConKey
+ , Just co1_2a <- opt_trans_rule co1 co2a
+ = if isIdNormCo co1_2a
+ then co2b
+ else opt_trans2 co1_2a co2b
+
+opt_trans2 co1 co2
+ = mkTransCoercion co1 co2
+
+------
+opt_trans_rule :: NormalNonIdCo -> NormalNonIdCo -> Maybe NormalCo
+opt_trans_rule (TyConApp tc1 args1) (TyConApp tc2 args2)
+ | tc1 == tc2
+ = case isCoercionTyCon_maybe tc1 of
+ Nothing
+ -> Just (TyConApp tc1 (opt_transL args1 args2))
+ Just (arity, desc)
+ | arity == length args1
+ -> opt_trans_rule_equal_tc desc args1 args2
+ | otherwise
+ -> case opt_trans_rule_equal_tc desc
+ (take arity args1)
+ (take arity args2) of
+ Just co -> Just $ mkAppTys co $
+ opt_transL (drop arity args1) (drop arity args2)
+ Nothing -> Nothing
+
+-- Push transitivity inside apply
+opt_trans_rule co1 co2
+ | Just (co1a, co1b) <- splitAppTy_maybe co1
+ , Just (co2a, co2b) <- etaApp_maybe co2
+ = Just (mkAppTy (opt_trans co1a co2a) (opt_trans co1b co2b))
+
+ | Just (co2a, co2b) <- splitAppTy_maybe co2
+ , Just (co1a, co1b) <- etaApp_maybe co1
+ = Just (mkAppTy (opt_trans co1a co2a) (opt_trans co1b co2b))
+
+-- Push transitivity inside (s~t)=>r
+opt_trans_rule co1 co2
+ | Just (s1,t1,r1) <- splitCoPredTy_maybe co1
+ , Just (s2,t2,r2) <- etaCoPred_maybe co2
+ = Just (mkCoPredTy (opt_trans s1 s2) (opt_trans t1 t2) (opt_trans r1 r2))
+
+ | Just (s2,t2,r2) <- splitCoPredTy_maybe co2
+ , Just (s1,t1,r1) <- etaCoPred_maybe co1
+ = Just (mkCoPredTy (opt_trans s1 s2) (opt_trans t1 t2) (opt_trans r1 r2))
+
+-- Push transitivity inside forall
+opt_trans_rule co1 co2
+ | Just (tv1,r1) <- splitTypeForAll_maybe co1
+ , Just (tv2,r2) <- etaForAll_maybe co2
+ , let r2' = substTyWith [tv2] [TyVarTy tv1] r2
+ = Just (ForAllTy tv1 (opt_trans2 r1 r2'))
+
+ | Just (tv2,r2) <- splitTypeForAll_maybe co2
+ , Just (tv1,r1) <- etaForAll_maybe co1
+ , let r1' = substTyWith [tv1] [TyVarTy tv2] r1
+ = Just (ForAllTy tv1 (opt_trans2 r1' r2))
+
+opt_trans_rule co1 co2
+{- Omitting for now, because unsound
+ | Just (sym1, (ax_tc1, ax1_args, ax_tvs, ax_lhs, ax_rhs)) <- co1_is_axiom_maybe
+ , Just (sym2, (ax_tc2, ax2_args, _, _, _)) <- co2_is_axiom_maybe
+ , ax_tc1 == ax_tc2
+ , sym1 /= sym2
+ = Just $
+ if sym1
+ then substTyWith ax_tvs (opt_transL (map mkSymCoercion ax1_args) ax2_args) ax_rhs
+ else substTyWith ax_tvs (opt_transL ax1_args (map mkSymCoercion ax2_args)) ax_lhs
+-}
+
+ | Just (sym, (ax_tc, ax_args, ax_tvs, ax_lhs, _)) <- co1_is_axiom_maybe
+ , Just cos <- matchesAxiomLhs ax_tvs ax_lhs co2
+ = Just $
+ if sym
+ then mkSymCoercion $ TyConApp ax_tc (opt_transL (map mkSymCoercion cos) ax_args)
+ else TyConApp ax_tc (opt_transL ax_args cos)
+
+ | Just (sym, (ax_tc, ax_args, ax_tvs, ax_lhs, _)) <- isAxiom_maybe co2
+ , Just cos <- matchesAxiomLhs ax_tvs ax_lhs co1
+ = Just $
+ if sym
+ then mkSymCoercion $ TyConApp ax_tc (opt_transL ax_args (map mkSymCoercion cos))
+ else TyConApp ax_tc (opt_transL cos ax_args)
+ where
+ co1_is_axiom_maybe = isAxiom_maybe co1
+ co2_is_axiom_maybe = isAxiom_maybe co2
+
+opt_trans_rule co1 co2 -- Identity rule
+ | (ty1,_) <- coercionKind co1
+ , (_,ty2) <- coercionKind co2
+ , ty1 `coreEqType` ty2
+ = Just ty2
+
+opt_trans_rule _ _ = Nothing
+
+-----------
+isAxiom_maybe :: Coercion -> Maybe (Bool, (TyCon, [Coercion], [TyVar], Type, Type))
+isAxiom_maybe co
+ | Just (tc, args) <- splitTyConApp_maybe co
+ , Just (_, desc) <- isCoercionTyCon_maybe tc
+ = case desc of
+ CoAxiom { co_ax_tvs = tvs, co_ax_lhs = lhs, co_ax_rhs = rhs }
+ -> Just (False, (tc, args, tvs, lhs, rhs))
+ CoSym | (arg1:_) <- args
+ -> case isAxiom_maybe arg1 of
+ Nothing -> Nothing
+ Just (sym, stuff) -> Just (not sym, stuff)
+ _ -> Nothing
+ | otherwise
+ = Nothing
+
+matchesAxiomLhs :: [TyVar] -> Type -> Type -> Maybe [Type]
+matchesAxiomLhs tvs ty_tmpl ty
+ = case tcMatchTy (mkVarSet tvs) ty_tmpl ty of
+ Nothing -> Nothing
+ Just subst -> Just (map (substTyVar subst) tvs)
+
+-----------
+opt_trans_rule_equal_tc :: CoTyConDesc -> [Coercion] -> [Coercion] -> Maybe Coercion
+-- Rules for Coercion TyCons only
+
+-- Push transitivity inside instantiation
+opt_trans_rule_equal_tc desc [co1,ty1] [co2,ty2]
+ | CoInst <- desc
+ , ty1 `coreEqType` ty2
+ , co1 `compatible_co` co2
+ = Just (mkInstCoercion (opt_trans2 co1 co2) ty1)
+
+opt_trans_rule_equal_tc desc [co1] [co2]
+ | CoLeft <- desc, is_compat = Just (mkLeftCoercion res_co)
+ | CoRight <- desc, is_compat = Just (mkRightCoercion res_co)
+ | CoCsel1 <- desc, is_compat = Just (mkCsel1Coercion res_co)
+ | CoCsel2 <- desc, is_compat = Just (mkCsel2Coercion res_co)
+ | CoCselR <- desc, is_compat = Just (mkCselRCoercion res_co)
+ where
+ is_compat = co1 `compatible_co` co2
+ res_co = opt_trans2 co1 co2
+
+opt_trans_rule_equal_tc _ _ _ = Nothing
+
+-------------
+compatible_co :: Coercion -> Coercion -> Bool
+-- Check whether (co1 . co2) will be well-kinded
+compatible_co co1 co2
+ = x1 `coreEqType` x2
+ where
+ (_,x1) = coercionKind co1
+ (x2,_) = coercionKind co2
+
+-------------
+etaForAll_maybe :: Coercion -> Maybe (TyVar, Coercion)
+-- Try to make the coercion be of form (forall tv. co)
+etaForAll_maybe co
+ | Just (tv, r) <- splitForAllTy_maybe co
+ , not (isCoVar tv) -- Check it is a *type* forall, not a (t1~t2)=>co
+ = Just (tv, r)
+
+ | (ty1,ty2) <- coercionKind co
+ , Just (tv1, _) <- splitTypeForAll_maybe ty1
+ , Just (tv2, _) <- splitTypeForAll_maybe ty2
+ , tyVarKind tv1 `eqKind` tyVarKind tv2
+ = Just (tv1, mkInstCoercion co (mkTyVarTy tv1))
+
+ | otherwise
+ = Nothing
+
+etaCoPred_maybe :: Coercion -> Maybe (Coercion, Coercion, Coercion)
+etaCoPred_maybe co
+ | Just (s,t,r) <- splitCoPredTy_maybe co
+ = Just (s,t,r)
+
+ -- co :: (s1~t1)=>r1 ~ (s2~t2)=>r2
+ | (ty1,ty2) <- coercionKind co -- We know ty1,ty2 have same kind
+ , Just (s1,_,_) <- splitCoPredTy_maybe ty1
+ , Just (s2,_,_) <- splitCoPredTy_maybe ty2
+ , typeKind s1 `eqKind` typeKind s2 -- t1,t2 have same kinds
+ = Just (mkCsel1Coercion co, mkCsel2Coercion co, mkCselRCoercion co)
+
+ | otherwise
+ = Nothing
+
+etaApp_maybe :: Coercion -> Maybe (Coercion, Coercion)
+etaApp_maybe co
+ | Just (co1, co2) <- splitAppTy_maybe co
+ = Just (co1, co2)
+
+ | (ty1,ty2) <- coercionKind co
+ , Just (ty1a, _) <- splitAppTy_maybe ty1
+ , Just (ty2a, _) <- splitAppTy_maybe ty2
+ , typeKind ty1a `eqKind` typeKind ty2a
+ = Just (mkLeftCoercion co, mkRightCoercion co)
+
+ | otherwise
+ = Nothing
+
+-------------
+splitTypeForAll_maybe :: Type -> Maybe (TyVar, Type)
+-- Returns Just only for a *type* forall, not a (t1~t2)=>co
+splitTypeForAll_maybe ty
+ | Just (tv, rty) <- splitForAllTy_maybe ty
+ , not (isCoVar tv)
+ = Just (tv, rty)
+
+ | otherwise
+ = Nothing
+
+-------------
+isIdNormCo :: NormalCo -> Bool
+-- Cheap identity test: look for coercions with no coercion variables at all
+-- So it'll return False for (sym g `trans` g)
+isIdNormCo ty = go ty
+ where
+ go (TyVarTy tv) = not (isCoVar tv)
+ go (AppTy t1 t2) = go t1 && go t2
+ go (FunTy t1 t2) = go t1 && go t2
+ go (ForAllTy tv ty) = go (tyVarKind tv) && go ty
+ go (TyConApp tc tys) = not (isCoercionTyCon tc) && all go tys
+ go (PredTy (IParam _ ty)) = go ty
+ go (PredTy (ClassP _ tys)) = all go tys
+ go (PredTy (EqPred t1 t2)) = go t1 && go t2
+\end{code}
diff --git a/compiler/types/TyCon.lhs b/compiler/types/TyCon.lhs index 958a0cb8a2..0959699356 100644 --- a/compiler/types/TyCon.lhs +++ b/compiler/types/TyCon.lhs @@ -8,11 +8,12 @@ The @TyCon@ datatype \begin{code} module TyCon( -- * Main TyCon data types - TyCon, FieldLabel, CoTyConKindChecker, + TyCon, FieldLabel, AlgTyConRhs(..), visibleDataCons, TyConParent(..), SynTyConRhs(..), + CoTyConDesc(..), AssocFamilyPermutation, -- ** Constructing TyCons @@ -199,7 +200,7 @@ data TyCon | PrimTyCon { tyConUnique :: Unique, tyConName :: Name, - tc_kind :: Kind, + tc_kind :: Kind, tyConArity :: Arity, -- SLPJ Oct06: I'm not sure what the significance -- of the arity of a primtycon is! @@ -217,13 +218,13 @@ data TyCon -- | Type coercions, such as @(~)@, @sym@, @trans@, @left@ and @right@. -- INVARIANT: Coercion TyCons are always fully applied - -- But note that a CoercionTyCon can be over-saturated in a type. + -- But note that a CoTyCon can be *over*-saturated in a type. -- E.g. (sym g1) Int will be represented as (TyConApp sym [g1,Int]) - | CoercionTyCon { + | CoTyCon { tyConUnique :: Unique, tyConName :: Name, tyConArity :: Arity, - coKindFun :: CoTyConKindChecker + coTcDesc :: CoTyConDesc } -- | Any types. Like tuples, this is a potentially-infinite family of TyCons @@ -250,23 +251,6 @@ data TyCon tyConName :: Name } -type CoTyConKindChecker = forall m. Monad m => CoTyConKindCheckerFun m - -type CoTyConKindCheckerFun m - = (Type -> m Kind) -- Kind checker for types - -> (Type -> m (Type,Type)) -- and for coercions - -> Bool -- True => apply consistency checks - -> [Type] -- Exactly right number of args - -> m (Type, Type) -- Kind of this application - - -- ^ Function that when given a list of the type arguments to the 'TyCon' - -- constructs the types that the resulting coercion relates. - -- Returns Nothing if ill-kinded. - -- - -- INVARIANT: 'coKindFun' is always applied to exactly 'tyConArity' args - -- E.g. for @trans (c1 :: ta=tb) (c2 :: tb=tc)@, the 'coKindFun' returns - -- the kind as a pair of types: @(ta, tc)@ - -- | Names of the fields in an algebraic record type type FieldLabel = Name @@ -324,7 +308,7 @@ data AlgTyConRhs -- See Note [Newtype eta] - nt_co :: Maybe TyCon -- ^ A 'TyCon' (which is always a 'CoercionTyCon') that can have a 'Coercion' + nt_co :: Maybe TyCon -- ^ A 'TyCon' (which is always a 'CoTyCon') that can have a 'Coercion' -- extracted from it to create the @newtype@ from the representation 'Type'. -- -- This field is optional for non-recursive @newtype@s only. @@ -377,7 +361,7 @@ data TyConParent -- of the current 'TyCon' (not the family one). INVARIANT: -- the number of types matches the arity of the family 'TyCon' -- - -- 3) A 'CoercionTyCon' identifying the representation + -- 3) A 'CoTyCon' identifying the representation -- type with the type instance family | FamilyTyCon TyCon @@ -409,6 +393,20 @@ data SynTyConRhs | SynonymTyCon Type -- ^ The synonym mentions head type variables. It acts as a -- template for the expansion when the 'TyCon' is applied to some -- types. + +-------------------- +data CoTyConDesc + = CoSym | CoTrans + | CoLeft | CoRight + | CoCsel1 | CoCsel2 | CoCselR + | CoInst + + | CoAxiom -- C tvs : F lhs-tys ~ rhs-ty + { co_ax_tvs :: [TyVar] + , co_ax_lhs :: Type + , co_ax_rhs :: Type } + + | CoUnsafe \end{code} Note [Newtype coercions] @@ -420,7 +418,7 @@ newtype, to the newtype itself. For example, newtype T a = MkT (a -> a) the NewTyCon for T will contain nt_co = CoT where CoT t : T t ~ t -> -t. This TyCon is a CoercionTyCon, so it does not have a kind on its +t. This TyCon is a CoTyCon, so it does not have a kind on its own; it basically has its own typing rule for the fully-applied version. If the newtype T has k type variables then CoT has arity at most k. In the case that the right hand side is a type application @@ -438,7 +436,7 @@ and then when we used CoT at a particular type, s, we'd say CoT @ s which encodes as (TyConApp instCoercionTyCon [TyConApp CoT [], s]) -But in GHC we instead make CoT into a new piece of type syntax, CoercionTyCon, +But in GHC we instead make CoT into a new piece of type syntax, CoTyCon, (like instCoercionTyCon, symCoercionTyCon etc), which must always be saturated, but which encodes as TyConApp CoT [s] @@ -710,21 +708,14 @@ mkSynTyCon name kind tyvars rhs parent -- | Create a coercion 'TyCon' mkCoercionTyCon :: Name -> Arity - -> CoTyConKindChecker + -> CoTyConDesc -> TyCon -mkCoercionTyCon name arity rule_fn - = CoercionTyCon { +mkCoercionTyCon name arity desc + = CoTyCon { tyConName = name, tyConUnique = nameUnique name, tyConArity = arity, -#ifdef DEBUG - coKindFun = \ ty co fail args -> - ASSERT2( length args == arity, ppr name ) - rule_fn ty co fail args -#else - coKindFun = rule_fn -#endif - } + coTcDesc = desc } mkAnyTyCon :: Name -> Kind -> TyCon mkAnyTyCon name kind @@ -799,11 +790,6 @@ isNewTyCon :: TyCon -> Bool isNewTyCon (AlgTyCon {algTcRhs = NewTyCon {}}) = True isNewTyCon _ = False -tyConHasKind :: TyCon -> Bool -tyConHasKind (SuperKindTyCon {}) = False -tyConHasKind (CoercionTyCon {}) = False -tyConHasKind _ = True - -- | Take a 'TyCon' apart into the 'TyVar's it scopes over, the 'Type' it expands -- into, and (possibly) a coercion from the representation type to the @newtype@. -- Returns @Nothing@ if this is not possible. @@ -852,9 +838,9 @@ isOpenSynTyCon tycon = isSynTyCon tycon && isOpenTyCon tycon isDecomposableTyCon :: TyCon -> Bool -- True iff we can deocmpose (T a b c) into ((T a b) c) -- Specifically NOT true of synonyms (open and otherwise) and coercions -isDecomposableTyCon (SynTyCon {}) = False -isDecomposableTyCon (CoercionTyCon {}) = False -isDecomposableTyCon _other = True +isDecomposableTyCon (SynTyCon {}) = False +isDecomposableTyCon (CoTyCon {}) = False +isDecomposableTyCon _other = True -- | Is this an algebraic 'TyCon' declared with the GADT syntax? isGadtSyntaxTyCon :: TyCon -> Bool @@ -972,15 +958,15 @@ isAnyTyCon _ = False -- | Attempt to pull a 'TyCon' apart into the arity and 'coKindFun' of -- a coercion 'TyCon'. Returns @Nothing@ if the 'TyCon' is not of the -- appropriate kind -isCoercionTyCon_maybe :: Monad m => TyCon -> Maybe (Arity, CoTyConKindCheckerFun m) -isCoercionTyCon_maybe (CoercionTyCon {tyConArity = ar, coKindFun = rule}) - = Just (ar, rule) +isCoercionTyCon_maybe :: TyCon -> Maybe (Arity, CoTyConDesc) +isCoercionTyCon_maybe (CoTyCon {tyConArity = ar, coTcDesc = desc}) + = Just (ar, desc) isCoercionTyCon_maybe _ = Nothing -- | Is this a 'TyCon' that represents a coercion? isCoercionTyCon :: TyCon -> Bool -isCoercionTyCon (CoercionTyCon {}) = True -isCoercionTyCon _ = False +isCoercionTyCon (CoTyCon {}) = True +isCoercionTyCon _ = False -- | Identifies implicit tycons that, in particular, do not go into interface -- files (because they are implicitly reconstructed when the interface is @@ -1000,7 +986,7 @@ isImplicitTyCon tycon | isTyConAssoc tycon = True isTupleTyCon tycon isImplicitTyCon _other = True -- catches: FunTyCon, PrimTyCon, - -- CoercionTyCon, SuperKindTyCon + -- CoTyCon, SuperKindTyCon \end{code} @@ -1064,7 +1050,12 @@ tyConKind (TupleTyCon { tc_kind = k }) = k tyConKind (SynTyCon { tc_kind = k }) = k tyConKind (PrimTyCon { tc_kind = k }) = k tyConKind (AnyTyCon { tc_kind = k }) = k -tyConKind tc = pprPanic "tyConKind" (ppr tc) +tyConKind tc = pprPanic "tyConKind" (ppr tc) -- SuperKindTyCon and CoTyCon + +tyConHasKind :: TyCon -> Bool +tyConHasKind (SuperKindTyCon {}) = False +tyConHasKind (CoTyCon {}) = False +tyConHasKind _ = True -- | As 'tyConDataCons_maybe', but returns the empty list of constructors if no constructors -- could be found @@ -1243,6 +1234,18 @@ instance Ord TyCon where instance Uniquable TyCon where getUnique tc = tyConUnique tc +instance Outputable CoTyConDesc where + ppr CoSym = ptext (sLit "SYM") + ppr CoTrans = ptext (sLit "TRANS") + ppr CoLeft = ptext (sLit "LEFT") + ppr CoRight = ptext (sLit "RIGHT") + ppr CoCsel1 = ptext (sLit "CSEL1") + ppr CoCsel2 = ptext (sLit "CSEL2") + ppr CoCselR = ptext (sLit "CSELR") + ppr CoInst = ptext (sLit "INST") + ppr CoUnsafe = ptext (sLit "UNSAFE") + ppr (CoAxiom {}) = ptext (sLit "AXIOM") + instance Outputable TyCon where ppr tc = ppr (getName tc) diff --git a/compiler/types/Type.lhs b/compiler/types/Type.lhs index 242e603569..f894cd304f 100644 --- a/compiler/types/Type.lhs +++ b/compiler/types/Type.lhs @@ -47,7 +47,7 @@ module Type ( tyFamInsts, predFamInsts, -- (Source types) - mkPredTy, mkPredTys, mkFamilyTyConApp, + mkPredTy, mkPredTys, mkFamilyTyConApp, isEqPred, -- ** Common type constructors funTyCon, @@ -63,9 +63,6 @@ module Type ( -- $kind_subtyping Kind, SimpleKind, KindVar, - -- ** Deconstructing Kinds - kindFunResult, splitKindFunTys, splitKindFunTysN, splitKindFunTy_maybe, - -- ** Common Kinds and SuperKinds liftedTypeKind, unliftedTypeKind, openTypeKind, argTypeKind, ubxTupleKind, @@ -76,18 +73,9 @@ module Type ( liftedTypeKindTyCon, openTypeKindTyCon, unliftedTypeKindTyCon, argTypeKindTyCon, ubxTupleKindTyCon, - -- ** Predicates on Kinds - isLiftedTypeKind, isUnliftedTypeKind, isOpenTypeKind, - isUbxTupleKind, isArgTypeKind, isKind, isTySuperKind, - isCoSuperKind, isSuperKind, isCoercionKind, isEqPred, - mkArrowKind, mkArrowKinds, - - isSubArgTypeKind, isSubOpenTypeKind, isSubKind, defaultKind, eqKind, - isSubKindCon, - -- * Type free variables tyVarsOfType, tyVarsOfTypes, tyVarsOfPred, tyVarsOfTheta, - typeKind, expandTypeSynonyms, + expandTypeSynonyms, -- * Tidying type related things up for printing tidyType, tidyTypes, @@ -153,7 +141,6 @@ import VarSet import Name import Class -import PrelNames import TyCon -- others @@ -791,6 +778,10 @@ mkPredTy pred = PredTy pred mkPredTys :: ThetaType -> [Type] mkPredTys preds = map PredTy preds +isEqPred :: PredType -> Bool +isEqPred (EqPred _ _) = True +isEqPred _ = False + predTypeRep :: PredType -> Type -- ^ Convert a 'PredType' to its representation type. However, it unwraps -- only the outermost level; for example, the result might be a newtype application @@ -834,44 +825,10 @@ pprSourceTyCon tycon %************************************************************************ %* * -\subsection{Kinds and free variables} + The free variables of a type %* * %************************************************************************ ---------------------------------------------------------------------- - Finding the kind of a type - ~~~~~~~~~~~~~~~~~~~~~~~~~~ -\begin{code} -typeKind :: Type -> Kind -typeKind (TyConApp tycon tys) = ASSERT( not (isCoercionTyCon tycon) ) - -- We should be looking for the coercion kind, - -- not the type kind - foldr (\_ k -> kindFunResult k) (tyConKind tycon) tys -typeKind (PredTy pred) = predKind pred -typeKind (AppTy fun _) = kindFunResult (typeKind fun) -typeKind (ForAllTy _ ty) = typeKind ty -typeKind (TyVarTy tyvar) = tyVarKind tyvar -typeKind (FunTy _arg res) - -- Hack alert. The kind of (Int -> Int#) is liftedTypeKind (*), - -- not unliftedTypKind (#) - -- The only things that can be after a function arrow are - -- (a) types (of kind openTypeKind or its sub-kinds) - -- (b) kinds (of super-kind TY) (e.g. * -> (* -> *)) - | isTySuperKind k = k - | otherwise = ASSERT( isSubOpenTypeKind k) liftedTypeKind - where - k = typeKind res - -predKind :: PredType -> Kind -predKind (EqPred {}) = coSuperKind -- A coercion kind! -predKind (ClassP {}) = liftedTypeKind -- Class and implicitPredicates are -predKind (IParam {}) = liftedTypeKind -- always represented by lifted types -\end{code} - - ---------------------------------------------------------------------- - Free variables of a type - ~~~~~~~~~~~~~~~~~~~~~~~~ \begin{code} tyVarsOfType :: Type -> TyVarSet -- ^ NB: for type synonyms tyVarsOfType does /not/ expand the synonym @@ -1587,20 +1544,20 @@ subst_ty :: TvSubst -> Type -> Type subst_ty subst ty = go ty where - go (TyVarTy tv) = substTyVar subst tv - go (TyConApp tc tys) = let args = map go tys - in args `seqList` TyConApp tc args + go (TyVarTy tv) = substTyVar subst tv + go (TyConApp tc tys) = let args = map go tys + in args `seqList` TyConApp tc args - go (PredTy p) = PredTy $! (substPred subst p) + go (PredTy p) = PredTy $! (substPred subst p) - go (FunTy arg res) = (FunTy $! (go arg)) $! (go res) - go (AppTy fun arg) = mkAppTy (go fun) $! (go arg) + go (FunTy arg res) = (FunTy $! (go arg)) $! (go res) + go (AppTy fun arg) = mkAppTy (go fun) $! (go arg) -- The mkAppTy smart constructor is important -- we might be replacing (a Int), represented with App -- by [Int], represented with TyConApp - go (ForAllTy tv ty) = case substTyVarBndr subst tv of - (subst', tv') -> - ForAllTy tv' $! (subst_ty subst' ty) + go (ForAllTy tv ty) = case substTyVarBndr subst tv of + (subst', tv') -> + ForAllTy tv' $! (subst_ty subst' ty) substTyVar :: TvSubst -> TyVar -> Type substTyVar subst@(TvSubst _ _) tv @@ -1710,133 +1667,3 @@ When unifying two internal type variables, we collect their kind constraints by finding the GLB of the two. Since the partial order is a tree, they only have a glb if one is a sub-kind of the other. In that case, we bind the less-informative one to the more informative one. Neat, eh? - - -\begin{code} - -\end{code} - -%************************************************************************ -%* * - Functions over Kinds -%* * -%************************************************************************ - -\begin{code} --- | Essentially 'funResultTy' on kinds -kindFunResult :: Kind -> Kind -kindFunResult k = funResultTy k - --- | Essentially 'splitFunTys' on kinds -splitKindFunTys :: Kind -> ([Kind],Kind) -splitKindFunTys k = splitFunTys k - -splitKindFunTy_maybe :: Kind -> Maybe (Kind,Kind) -splitKindFunTy_maybe = splitFunTy_maybe - --- | Essentially 'splitFunTysN' on kinds -splitKindFunTysN :: Int -> Kind -> ([Kind],Kind) -splitKindFunTysN k = splitFunTysN k - --- | See "Type#kind_subtyping" for details of the distinction between these 'Kind's -isUbxTupleKind, isOpenTypeKind, isArgTypeKind, isUnliftedTypeKind :: Kind -> Bool -isOpenTypeKindCon, isUbxTupleKindCon, isArgTypeKindCon, - isUnliftedTypeKindCon, isSubArgTypeKindCon :: TyCon -> Bool - -isOpenTypeKindCon tc = tyConUnique tc == openTypeKindTyConKey - -isOpenTypeKind (TyConApp tc _) = isOpenTypeKindCon tc -isOpenTypeKind _ = False - -isUbxTupleKindCon tc = tyConUnique tc == ubxTupleKindTyConKey - -isUbxTupleKind (TyConApp tc _) = isUbxTupleKindCon tc -isUbxTupleKind _ = False - -isArgTypeKindCon tc = tyConUnique tc == argTypeKindTyConKey - -isArgTypeKind (TyConApp tc _) = isArgTypeKindCon tc -isArgTypeKind _ = False - -isUnliftedTypeKindCon tc = tyConUnique tc == unliftedTypeKindTyConKey - -isUnliftedTypeKind (TyConApp tc _) = isUnliftedTypeKindCon tc -isUnliftedTypeKind _ = False - -isSubOpenTypeKind :: Kind -> Bool --- ^ True of any sub-kind of OpenTypeKind (i.e. anything except arrow) -isSubOpenTypeKind (FunTy k1 k2) = ASSERT2 ( isKind k1, text "isSubOpenTypeKind" <+> ppr k1 <+> text "::" <+> ppr (typeKind k1) ) - ASSERT2 ( isKind k2, text "isSubOpenTypeKind" <+> ppr k2 <+> text "::" <+> ppr (typeKind k2) ) - False -isSubOpenTypeKind (TyConApp kc []) = ASSERT( isKind (TyConApp kc []) ) True -isSubOpenTypeKind other = ASSERT( isKind other ) False - -- This is a conservative answer - -- It matters in the call to isSubKind in - -- checkExpectedKind. - -isSubArgTypeKindCon kc - | isUnliftedTypeKindCon kc = True - | isLiftedTypeKindCon kc = True - | isArgTypeKindCon kc = True - | otherwise = False - -isSubArgTypeKind :: Kind -> Bool --- ^ True of any sub-kind of ArgTypeKind -isSubArgTypeKind (TyConApp kc []) = isSubArgTypeKindCon kc -isSubArgTypeKind _ = False - --- | Is this a super-kind (i.e. a type-of-kinds)? -isSuperKind :: Type -> Bool -isSuperKind (TyConApp (skc) []) = isSuperKindTyCon skc -isSuperKind _ = False - --- | Is this a kind (i.e. a type-of-types)? -isKind :: Kind -> Bool -isKind k = isSuperKind (typeKind k) - -isSubKind :: Kind -> Kind -> Bool --- ^ @k1 \`isSubKind\` k2@ checks that @k1@ <: @k2@ -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 _ _ = False - -eqKind :: Kind -> Kind -> Bool -eqKind = tcEqType - -isSubKindCon :: TyCon -> TyCon -> Bool --- ^ @kc1 \`isSubKindCon\` kc2@ checks that @kc1@ <: @kc2@ -isSubKindCon kc1 kc2 - | isLiftedTypeKindCon kc1 && isLiftedTypeKindCon kc2 = True - | isUnliftedTypeKindCon kc1 && isUnliftedTypeKindCon kc2 = True - | isUbxTupleKindCon kc1 && isUbxTupleKindCon kc2 = True - | isOpenTypeKindCon kc2 = True - -- we already know kc1 is not a fun, its a TyCon - | isArgTypeKindCon kc2 && isSubArgTypeKindCon kc1 = True - | otherwise = False - -defaultKind :: Kind -> Kind --- ^ Used when generalising: default kind ? and ?? to *. See "Type#kind_subtyping" for more --- information on what that means - --- When we generalise, we make generic type variables whose kind is --- simple (* or *->* etc). So generic type variables (other than --- built-in constants like 'error') always have simple kinds. This is important; --- consider --- f x = True --- We want f to get type --- f :: forall (a::*). a -> Bool --- Not --- f :: forall (a::??). a -> Bool --- because that would allow a call like (f 3#) as well as (f True), ---and the calling conventions differ. This defaulting is done in TcMType.zonkTcTyVarBndr. -defaultKind k - | isSubOpenTypeKind k = liftedTypeKind - | isSubArgTypeKind k = liftedTypeKind - | otherwise = k - -isEqPred :: PredType -> Bool -isEqPred (EqPred _ _) = True -isEqPred _ = False -\end{code} diff --git a/compiler/types/Unify.lhs b/compiler/types/Unify.lhs index 7195e5b2f5..a9586b6bf4 100644 --- a/compiler/types/Unify.lhs +++ b/compiler/types/Unify.lhs @@ -16,7 +16,7 @@ module Unify ( Refinement, emptyRefinement, isEmptyRefinement, matchRefine, refineType, refinePred, refineResType, - -- side-effect free unification + -- Side-effect free unification tcUnifyTys, BindFlag(..) ) where diff --git a/compiler/utils/Util.lhs b/compiler/utils/Util.lhs index 16a1628d35..69b8c7ed32 100644 --- a/compiler/utils/Util.lhs +++ b/compiler/utils/Util.lhs @@ -30,6 +30,9 @@ module Util ( isIn, isn'tIn, + -- * Tuples + fstOf3, sndOf3, thirdOf3, + -- * List operations controlled by another list takeList, dropList, splitAtList, split, dropTail, @@ -181,6 +184,15 @@ nTimes 1 f = f nTimes n f = f . nTimes (n-1) f \end{code} +\begin{code} +fstOf3 :: (a,b,c) -> a +sndOf3 :: (a,b,c) -> b +thirdOf3 :: (a,b,c) -> c +fstOf3 (a,_,_) = a +sndOf3 (_,b,_) = b +thirdOf3 (_,_,c) = c +\end{code} + %************************************************************************ %* * \subsection[Utils-lists]{General list processing} |