import Maybe
import Control.Monad.Reader
--- just for printing warnings
-import System.IO.Unsafe
import Core
import Printer()
require False s = fail s
require True _ = return ()
-requireM :: CheckResult Bool -> String -> CheckResult ()
-requireM cond s =
- do b <- cond
- require b s
-
{- Environments. -}
type Tvenv = Env Tvar Kind -- type variables (local only)
type Tcenv = Env Tcon KindOrCoercion -- type constructors
-type Tsenv = Env Tcon ([Tvar],Ty) -- type synonyms
type Cenv = Env Dcon Ty -- data constructors
type Venv = Env Var Ty -- values
type Menv = Env AnMname Envs -- modules
-data Envs = Envs {tcenv_::Tcenv,tsenv_::Tsenv,cenv_::Cenv,venv_::Venv} -- all the exportable envs
+data Envs = Envs {tcenv_::Tcenv,cenv_::Cenv,venv_::Venv} -- all the exportable envs
deriving Show
{- Extend an environment, checking for illegal shadowing of identifiers (for term
checkModule :: Menv -> Module -> CheckRes Menv
checkModule globalEnv (Module mn tdefs vdefgs) =
runReaderT
- (do (tcenv, tsenv, cenv) <- mkTypeEnvs tdefs
- (e_venv,_) <- foldM (checkVdefg True (tcenv,tsenv,eempty,cenv))
+ (do (tcenv, cenv) <- mkTypeEnvs tdefs
+ (e_venv,_) <- foldM (checkVdefg True (tcenv,eempty,cenv))
(eempty,eempty)
vdefgs
return (eextend globalEnv
- (mn,Envs{tcenv_=tcenv,tsenv_=tsenv,cenv_=cenv,venv_=e_venv})))
- (mn, globalEnv)
+ (mn,Envs{tcenv_=tcenv,cenv_=cenv,venv_=e_venv})))
+ -- avoid name shadowing
+ (mn, eremove globalEnv mn)
-- Like checkModule, but doesn't typecheck the code, instead just
-- returning declared types for top-level defns.
-- of unpleasant.
envsModule :: Menv -> Module -> Menv
envsModule globalEnv (Module mn tdefs vdefgs) =
- let (tcenv, tsenv, cenv) = mkTypeEnvsNoChecking tdefs
+ let (tcenv, cenv) = mkTypeEnvsNoChecking tdefs
e_venv = foldr vdefgTypes eempty vdefgs in
eextend globalEnv (mn,
- (Envs{tcenv_=tcenv,tsenv_=tsenv,cenv_=cenv,venv_=e_venv}))
+ (Envs{tcenv_=tcenv,cenv_=cenv,venv_=e_venv}))
where vdefgTypes :: Vdefg -> Venv -> Venv
vdefgTypes (Nonrec (Vdef (v,t,_))) e =
add [(v,t)] e
addOne ((Nothing,_),_) e = e
addOne ((Just _,v),t) e = eextend e (v,t)
-checkTdef0 :: (Tcenv,Tsenv) -> Tdef -> CheckResult (Tcenv,Tsenv)
-checkTdef0 (tcenv,tsenv) tdef = ch tdef
+checkTdef0 :: Tcenv -> Tdef -> CheckResult Tcenv
+checkTdef0 tcenv tdef = ch tdef
where
ch (Data (m,c) tbs _) =
do mn <- getMname
requireModulesEq m mn "data type declaration" tdef False
- tcenv' <- extendM NotTv tcenv (c, Kind k)
- return (tcenv',tsenv)
+ extendM NotTv tcenv (c, Kind k)
where k = foldr Karrow Klifted (map snd tbs)
- ch (Newtype (m,c) tbs ((_,coercion),cTbs,coercionKind) rhs) =
+ ch (Newtype (m,c) coVar tbs rhs) =
do mn <- getMname
requireModulesEq m mn "newtype declaration" tdef False
tcenv' <- extendM NotTv tcenv (c, Kind k)
-- add newtype axiom to env
- tcenv'' <- extendM NotTv tcenv'
- (coercion, Coercion $ DefinedCoercion cTbs coercionKind)
- tsenv' <- case rhs of
- Nothing -> return tsenv
- Just rep -> extendM NotTv tsenv (c,(map fst tbs,rep))
- return (tcenv'', tsenv')
+ tcenv'' <- envPlusNewtype tcenv' (m,c) coVar tbs rhs
+ return tcenv''
where k = foldr Karrow Klifted (map snd tbs)
-processTdef0NoChecking :: (Tcenv,Tsenv) -> Tdef -> (Tcenv,Tsenv)
-processTdef0NoChecking (tcenv,tsenv) tdef = ch tdef
+processTdef0NoChecking :: Tcenv -> Tdef -> Tcenv
+processTdef0NoChecking tcenv tdef = ch tdef
where
- ch (Data (_,c) tbs _) = (eextend tcenv (c, Kind k), tsenv)
+ ch (Data (_,c) tbs _) = eextend tcenv (c, Kind k)
where k = foldr Karrow Klifted (map snd tbs)
- ch (Newtype (_,c) tbs ((_,coercion),cTbs,coercionKind) rhs) =
- let tcenv' = eextend tcenv (c, Kind k)
+ ch (Newtype tc@(_,c) coercion tbs rhs) =
+ let tcenv' = eextend tcenv (c, Kind k) in
-- add newtype axiom to env
- tcenv'' = eextend tcenv'
- (coercion, Coercion $ DefinedCoercion cTbs coercionKind)
- tsenv' = maybe tsenv
- (\ rep -> eextend tsenv (c, (map fst tbs, rep))) rhs in
- (tcenv'', tsenv')
+ eextend tcenv'
+ (snd coercion, Coercion $ DefinedCoercion tbs
+ (foldl Tapp (Tcon tc) (map Tvar (fst (unzip tbs))), rhs))
where k = foldr Karrow Klifted (map snd tbs)
+
+envPlusNewtype :: Tcenv -> Qual Tcon -> Qual Tcon -> [Tbind] -> Ty
+ -> CheckResult Tcenv
+envPlusNewtype tcenv tyCon coVar tbs rep = extendM NotTv tcenv
+ (snd coVar, Coercion $ DefinedCoercion tbs
+ (foldl Tapp (Tcon tyCon)
+ (map Tvar (fst (unzip tbs))),
+ rep))
checkTdef :: Tcenv -> Cenv -> Tdef -> CheckResult Cenv
checkTdef tcenv cenv = ch
(foldr tArrow
(foldl Tapp (Tcon (Just mn,c))
(map (Tvar . fst) utbs)) ts) tbs
- ch (tdef@(Newtype _ tbs (_, coTbs, (coLhs, coRhs)) (Just t))) =
+ ch (tdef@(Newtype tc _ tbs t)) =
do tvenv <- foldM (extendM Tv) eempty tbs
- k <- checkTy (tcenv,tvenv) t
- -- Makes sure GHC is eta-expanding things properly
- require (length tbs == length coTbs) $
- ("Arity mismatch between newtycon and newtype coercion: "
- ++ show tdef)
- require (k `eqKind` Klifted) ("bad kind:\n" ++ show tdef)
- axiomTvenv <- foldM (extendM Tv) eempty coTbs
- kLhs <- checkTy (tcenv,axiomTvenv) coLhs
- kRhs <- checkTy (tcenv,axiomTvenv) coRhs
+ kRhs <- checkTy (tcenv,tvenv) t
+ require (kRhs `eqKind` Klifted) ("bad kind:\n" ++ show tdef)
+ kLhs <- checkTy (tcenv,tvenv)
+ (foldl Tapp (Tcon tc) (map Tvar (fst (unzip tbs))))
require (kLhs `eqKind` kRhs)
("Kind mismatch in newtype axiom types: " ++ show tdef
++ " kinds: " ++
(show kLhs) ++ " and " ++ (show kRhs))
return cenv
- ch (Newtype _ _ _ Nothing) =
- {- should only occur for recursive Newtypes -}
- return cenv
processCdef :: Cenv -> Tdef -> Cenv
processCdef cenv = ch
(map (Tvar . fst) utbs)) ts) tbs
ch _ = cenv
-mkTypeEnvs :: [Tdef] -> CheckResult (Tcenv, Tsenv, Cenv)
+mkTypeEnvs :: [Tdef] -> CheckResult (Tcenv, Cenv)
mkTypeEnvs tdefs = do
- (tcenv, tsenv) <- foldM checkTdef0 (eempty,eempty) tdefs
+ tcenv <- foldM checkTdef0 eempty tdefs
cenv <- foldM (checkTdef tcenv) eempty tdefs
- return (tcenv, tsenv, cenv)
+ return (tcenv, cenv)
-mkTypeEnvsNoChecking :: [Tdef] -> (Tcenv, Tsenv, Cenv)
+mkTypeEnvsNoChecking :: [Tdef] -> (Tcenv, Cenv)
mkTypeEnvsNoChecking tdefs =
- let (tcenv, tsenv) = foldl processTdef0NoChecking (eempty,eempty) tdefs
- cenv = foldl processCdef eempty tdefs in
- (tcenv, tsenv, cenv)
+ let tcenv = foldl processTdef0NoChecking eempty tdefs
+ cenv = foldl processCdef eempty tdefs in
+ (tcenv, cenv)
requireModulesEq :: Show a => Mname -> AnMname -> String -> a
-> Bool -> CheckResult ()
mkErrMsg :: Show a => String -> a -> String
mkErrMsg msg t = "wrong module name in " ++ msg ++ ":\n" ++ show t
-checkVdefg :: Bool -> (Tcenv,Tsenv,Tvenv,Cenv) -> (Venv,Venv)
+checkVdefg :: Bool -> (Tcenv,Tvenv,Cenv) -> (Venv,Venv)
-> Vdefg -> CheckResult (Venv,Venv)
-checkVdefg top_level (tcenv,tsenv,tvenv,cenv) (e_venv,l_venv) vdefg =
+checkVdefg top_level (tcenv,tvenv,cenv) (e_venv,l_venv) vdefg = do
+ mn <- getMname
case vdefg of
Rec vdefs ->
- do e_venv' <- foldM extendVenv e_venv e_vts
- l_venv' <- foldM extendVenv l_venv l_vts
- let env' = (tcenv,tsenv,tvenv,cenv,e_venv',l_venv')
- mapM_ (\ (vdef@(Vdef ((m,_),t,e))) ->
- do mn <- getMname
- requireModulesEq m mn "value definition" vdef True
- k <- checkTy (tcenv,tvenv) t
- require (k `eqKind` Klifted) ("unlifted kind in:\n" ++ show vdef)
- t' <- checkExp env' e
- requireM (equalTy tsenv t t')
- ("declared type doesn't match expression type in:\n" ++ show vdef ++ "\n" ++
- "declared type: " ++ show t ++ "\n" ++
- "expression type: " ++ show t')) vdefs
- return (e_venv',l_venv')
- where e_vts = [ (v,t) | Vdef ((Just _,v),t,_) <- vdefs ]
- l_vts = [ (v,t) | Vdef ((Nothing,v),t,_) <- vdefs]
- Nonrec (vdef@(Vdef ((m,v),t,e))) ->
- do mn <- getMname
- -- TODO: document this weirdness
- let isZcMain = vdefIsMainWrapper mn m
- unless isZcMain $
- requireModulesEq m mn "value definition" vdef True
- k <- checkTy (tcenv,tvenv) t
- require (not (k `eqKind` Kopen)) ("open kind in:\n" ++ show vdef)
- require ((not top_level) || (not (k `eqKind` Kunlifted)))
- ("top-level unlifted kind in:\n" ++ show vdef)
- t' <- checkExp (tcenv,tsenv,tvenv,cenv,e_venv,l_venv) e
- requireM (equalTy tsenv t t')
- ("declared type doesn't match expression type in:\n"
- ++ show vdef ++ "\n" ++
- "declared type: " ++ show t ++ "\n" ++
- "expression type: " ++ show t')
- if isNothing m then
- do l_venv' <- extendVenv l_venv (v,t)
- return (e_venv,l_venv')
- else
- -- awful, but avoids name shadowing --
- -- otherwise we'd have two bindings for "main"
- do e_venv' <- if isZcMain
- then return e_venv
- else extendVenv e_venv (v,t)
- return (e_venv',l_venv)
+ do (e_venv', l_venv') <- makeEnv mn vdefs
+ let env' = (tcenv,tvenv,cenv,e_venv',l_venv')
+ mapM_ (checkVdef (\ vdef k -> require (k `eqKind` Klifted)
+ ("unlifted kind in:\n" ++ show vdef)) env')
+ vdefs
+ return (e_venv', l_venv')
+ Nonrec vdef ->
+ do let env' = (tcenv, tvenv, cenv, e_venv, l_venv)
+ checkVdef (\ vdef k -> do
+ require (not (k `eqKind` Kopen)) ("open kind in:\n" ++ show vdef)
+ require ((not top_level) || (not (k `eqKind` Kunlifted)))
+ ("top-level unlifted kind in:\n" ++ show vdef)) env' vdef
+ makeEnv mn [vdef]
+
+ where makeEnv mn vdefs = do
+ ev <- foldM extendVenv e_venv e_vts
+ lv <- foldM extendVenv l_venv l_vts
+ return (ev, lv)
+ where e_vts = [ (v,t) | Vdef ((Just m,v),t,_) <- vdefs,
+ not (vdefIsMainWrapper mn (Just m))]
+ l_vts = [ (v,t) | Vdef ((Nothing,v),t,_) <- vdefs]
+ checkVdef checkKind env (vdef@(Vdef ((m,_),t,e))) = do
+ mn <- getMname
+ let isZcMain = vdefIsMainWrapper mn m
+ unless isZcMain $
+ requireModulesEq m mn "value definition" vdef True
+ k <- checkTy (tcenv,tvenv) t
+ checkKind vdef k
+ t' <- checkExp env e
+ require (t == t')
+ ("declared type doesn't match expression type in:\n"
+ ++ show vdef ++ "\n" ++
+ "declared type: " ++ show t ++ "\n" ++
+ "expression type: " ++ show t')
vdefIsMainWrapper :: AnMname -> Mname -> Bool
vdefIsMainWrapper enclosing defining =
- enclosing == mainMname && defining == wrapperMainMname
+ enclosing == mainMname && defining == wrapperMainAnMname
checkExpr :: AnMname -> Menv -> [Tdef] -> Venv -> Tvenv
-> Exp -> Ty
checkExpr mn menv tdefs venv tvenv e = case runReaderT (do
- (tcenv, tsenv, cenv) <- mkTypeEnvs tdefs
+ (tcenv, cenv) <- mkTypeEnvs tdefs
-- Since the preprocessor calls checkExpr after code has been
-- typechecked, we expect to find the external env in the Menv.
case (elookup menv mn) of
Just thisEnv ->
- checkExp (tcenv, tsenv, tvenv, cenv, (venv_ thisEnv), venv) e
+ checkExp (tcenv, tvenv, cenv, (venv_ thisEnv), venv) e
Nothing -> reportError e ("checkExpr: Environment for " ++
show mn ++ " not found")) (mn,menv) of
OkC t -> t
checkType :: AnMname -> Menv -> [Tdef] -> Tvenv -> Ty -> Kind
checkType mn menv tdefs tvenv t = case runReaderT (do
- (tcenv, _, _) <- mkTypeEnvs tdefs
+ (tcenv, _) <- mkTypeEnvs tdefs
checkTy (tcenv, tvenv) t) (mn, menv) of
OkC k -> k
FailC s -> reportError tvenv s
-checkExp :: (Tcenv,Tsenv,Tvenv,Cenv,Venv,Venv) -> Exp -> CheckResult Ty
-checkExp (tcenv,tsenv,tvenv,cenv,e_venv,l_venv) = ch
+checkExp :: (Tcenv,Tvenv,Cenv,Venv,Venv) -> Exp -> CheckResult Ty
+checkExp (tcenv,tvenv,cenv,e_venv,l_venv) = ch
where
ch e0 =
case e0 of
t2 <- ch e2
case t1 of
Tapp(Tapp(Tcon tc) t') t0 | tc == tcArrow ->
- do requireM (equalTy tsenv t2 t')
+ do require (t2 == t')
("type doesn't match at application in:\n" ++ show e0 ++ "\n" ++
"operator type: " ++ show t' ++ "\n" ++
"operand type: " ++ show t2)
"operator type: " ++ show t1)
Lam (Tb tb) e ->
do tvenv' <- extendTvenv tvenv tb
- t <- checkExp (tcenv,tsenv,tvenv',cenv,e_venv,l_venv) e
+ t <- checkExp (tcenv,tvenv',cenv,e_venv,l_venv) e
return (Tforall tb t)
Lam (Vb (vb@(_,vt))) e ->
do k <- checkTy (tcenv,tvenv) vt
("higher-order kind in:\n" ++ show e0 ++ "\n" ++
"kind: " ++ show k)
l_venv' <- extendVenv l_venv vb
- t <- checkExp (tcenv,tsenv,tvenv,cenv,e_venv,l_venv') e
+ t <- checkExp (tcenv,tvenv,cenv,e_venv,l_venv') e
require (not (isUtupleTy vt)) ("lambda-bound unboxed tuple in:\n" ++ show e0)
return (tArrow vt t)
Let vdefg e ->
- do (e_venv',l_venv') <- checkVdefg False (tcenv,tsenv,tvenv,cenv)
- (e_venv,l_venv) vdefg
- checkExp (tcenv,tsenv,tvenv,cenv,e_venv',l_venv') e
+ do (e_venv',l_venv') <- checkVdefg False (tcenv,tvenv,cenv)
+ (e_venv,l_venv) vdefg
+ checkExp (tcenv,tvenv,cenv,e_venv',l_venv') e
Case e (v,t) resultTy alts ->
do t' <- ch e
checkTy (tcenv,tvenv) t
- requireM (equalTy tsenv t t')
+ require (t == t')
("scrutinee declared type doesn't match expression type in:\n" ++ show e0 ++ "\n" ++
"declared type: " ++ show t ++ "\n" ++
"expression type: " ++ show t')
[Adefault _] -> return ()
_ -> fail ("no alternatives in case:\n" ++ show e0)
l_venv' <- extendVenv l_venv (v,t)
- t:ts <- mapM (checkAlt (tcenv,tsenv,tvenv,cenv,e_venv,l_venv') t) alts
- bs <- mapM (equalTy tsenv t) ts
- require (and bs)
+ t:ts <- mapM (checkAlt (tcenv,tvenv,cenv,e_venv,l_venv') t) alts
+ require (all (== t) ts)
("alternative types don't match in:\n" ++ show e0 ++ "\n" ++
"types: " ++ show (t:ts))
checkTy (tcenv,tvenv) resultTy
return t
c@(Cast e t) ->
do eTy <- ch e
- k <- checkTy (tcenv,tvenv) t
- case k of
- (Keq fromTy toTy) -> do
- require (eTy == fromTy) ("Type mismatch in cast: c = "
- ++ show c ++ " and " ++ show eTy
- ++ " and " ++ show fromTy)
- return toTy
- _ -> fail ("Cast with non-equality kind: " ++ show e
- ++ " and " ++ show t ++ " has kind " ++ show k)
+ (fromTy, toTy) <- checkTyCo (tcenv,tvenv) t
+ require (eTy == fromTy) ("Type mismatch in cast: c = "
+ ++ show c ++ "\nand eTy = " ++ show eTy
+ ++ "\n and " ++ show fromTy)
+ return toTy
Note _ e ->
ch e
External _ t ->
do checkTy (tcenv,eempty) t {- external types must be closed -}
return t
-checkAlt :: (Tcenv,Tsenv,Tvenv,Cenv,Venv,Venv) -> Ty -> Alt -> CheckResult Ty
-checkAlt (env@(tcenv,tsenv,tvenv,cenv,e_venv,l_venv)) t0 = ch
+checkAlt :: (Tcenv,Tvenv,Cenv,Venv,Venv) -> Ty -> Alt -> CheckResult Ty
+checkAlt (env@(tcenv,tvenv,cenv,e_venv,l_venv)) t0 = ch
where
ch a0 =
case a0 of
let (ct_res:ct_args) = map (substl (utvs++etvs') (uts++(map Tvar etvs))) (ct_res0:ct_args0)
zipWithM_
(\ct_arg vt ->
- requireM (equalTy tsenv ct_arg vt)
+ require (ct_arg == vt)
("pattern variable type doesn't match constructor argument type in:\n" ++ show a0 ++ "\n" ++
"pattern variable type: " ++ show ct_arg ++ "\n" ++
"constructor argument type: " ++ show vt)) ct_args vts
- requireM (equalTy tsenv ct_res t0)
+ require (ct_res == t0)
("pattern constructor type doesn't match scrutinee type in:\n" ++ show a0 ++ "\n" ++
"pattern constructor type: " ++ show ct_res ++ "\n" ++
"scrutinee type: " ++ show t0)
l_venv' <- foldM extendVenv l_venv vbs
- t <- checkExp (tcenv,tsenv,tvenv',cenv,e_venv,l_venv') e
+ t <- checkExp (tcenv,tvenv',cenv,e_venv,l_venv') e
checkTy (tcenv,tvenv) t {- check that existentials don't escape in result type -}
return t
Alit l e ->
do t <- checkLit l
- requireM (equalTy tsenv t t0)
+ require (t == t0)
("pattern type doesn't match scrutinee type in:\n" ++ show a0 ++ "\n" ++
"pattern type: " ++ show t ++ "\n" ++
"scrutinee type: " ++ show t0)
checkExp env e
checkTy :: (Tcenv,Tvenv) -> Ty -> CheckResult Kind
-checkTy es@(tcenv,tvenv) t = ch t
+checkTy es@(tcenv,tvenv) = ch
where
ch (Tvar tv) = lookupM tvenv tv
ch (Tcon qtc) = do
let (tvs, tks) = unzip tbs
argKs <- mapM (checkTy es) tys
let kPairs = zip argKs tks
- let kindsOk = all (uncurry eqKind) kPairs
- if not kindsOk &&
- all (uncurry subKindOf) kPairs
- -- GHC occasionally generates code like:
- -- :Co:TTypeable2 (->)
- -- where in this case, :Co:TTypeable2 expects an
- -- argument of kind (*->(*->*)) and (->) has kind
- -- (?->(?->*)). In general, I don't think it's
- -- sound to apply an arbitrary coercion to an
- -- argument that's a subkind of what it expects.
- then warn $ "Applying coercion " ++ show tc ++
- " to arguments of kind " ++ show argKs
- ++ " when it expects: " ++ show tks
- else require kindsOk
+ -- Simon says it's okay for these to be
+ -- subkinds
+ let kindsOk = all (uncurry subKindOf) kPairs
+ require kindsOk
("Kind mismatch in coercion app: " ++ show tks
++ " and " ++ show argKs ++ " t = " ++ show t)
return $ Keq (substl tvs tys from) (substl tvs tys to)
Nothing -> checkTapp t1 t2
where checkTapp t1 t2 = do
- k1 <- ch t1
+ k1 <- ch t1
k2 <- ch t2
case k1 of
- Karrow k11 k12 ->
- case k2 of
- Keq eqTy1 eqTy2 -> do
- -- Distribute the type operator over the
- -- coercion
- subK1 <- checkTy es eqTy1
- subK2 <- checkTy es eqTy2
- require (subK2 `subKindOf` k11 &&
- subK1 `subKindOf` k11) $
- kindError
- return $ Keq (Tapp t1 eqTy1) (Tapp t1 eqTy2)
- _ -> do
- require (k2 `subKindOf` k11) kindError
- return k12
+ Karrow k11 k12 -> do
+ require (k2 `subKindOf` k11) kindError
+ return k12
where kindError =
"kinds don't match in type application: "
++ show t ++ "\n" ++
ch (Tforall tb t) =
do tvenv' <- extendTvenv tvenv tb
- k <- checkTy (tcenv,tvenv') t
- return $ case k of
- -- distribute the forall
- Keq t1 t2 -> Keq (Tforall tb t1) (Tforall tb t2)
- _ -> k
+ checkTy (tcenv,tvenv') t
ch (TransCoercion t1 t2) = do
- k1 <- checkTy es t1
- k2 <- checkTy es t2
- case (k1, k2) of
- (Keq ty1 ty2, Keq ty3 ty4) | ty2 == ty3 ->
- return $ Keq ty1 ty4
- _ -> fail ("Bad kinds in trans. coercion: " ++
- show k1 ++ " " ++ show k2)
+ (ty1,ty2) <- checkTyCo es t1
+ (ty3,ty4) <- checkTyCo es t2
+ require (ty2 == ty3) ("Types don't match in trans. coercion: " ++
+ show ty2 ++ " and " ++ show ty3)
+ return $ Keq ty1 ty4
ch (SymCoercion t1) = do
- k <- checkTy es t1
- case k of
- Keq ty1 ty2 -> return $ Keq ty2 ty1
- _ -> fail ("Bad kind in sym. coercion: "
- ++ show k)
+ (ty1,ty2) <- checkTyCo es t1
+ return $ Keq ty2 ty1
ch (UnsafeCoercion t1 t2) = do
checkTy es t1
checkTy es t2
return $ Keq t1 t2
ch (LeftCoercion t1) = do
- k <- checkTy es t1
+ k <- checkTyCo es t1
case k of
- Keq (Tapp u _) (Tapp w _) -> return $ Keq u w
+ ((Tapp u _), (Tapp w _)) -> return $ Keq u w
_ -> fail ("Bad coercion kind in operand of left: " ++ show k)
ch (RightCoercion t1) = do
- k <- checkTy es t1
+ k <- checkTyCo es t1
case k of
- Keq (Tapp _ v) (Tapp _ x) -> return $ Keq v x
+ ((Tapp _ v), (Tapp _ x)) -> return $ Keq v x
_ -> fail ("Bad coercion kind in operand of left: " ++ show k)
-
-{- Type equality modulo newtype synonyms. -}
-equalTy :: Tsenv -> Ty -> Ty -> CheckResult Bool
-equalTy tsenv t1 t2 =
- do t1' <- expand t1
- t2' <- expand t2
- return (t1' == t2')
- where expand (Tvar v) = return (Tvar v)
- expand (Tcon qtc) = return (Tcon qtc)
- expand (Tapp t1 t2) =
- do t2' <- expand t2
- expapp t1 [t2']
- expand (Tforall tb t) =
- do t' <- expand t
- return (Tforall tb t')
- expand (TransCoercion t1 t2) = do
- exp1 <- expand t1
- exp2 <- expand t2
- return $ TransCoercion exp1 exp2
- expand (SymCoercion t) = do
- exp <- expand t
- return $ SymCoercion exp
- expand (UnsafeCoercion t1 t2) = do
- exp1 <- expand t1
- exp2 <- expand t2
- return $ UnsafeCoercion exp1 exp2
- expand (LeftCoercion t1) = do
- exp1 <- expand t1
- return $ LeftCoercion exp1
- expand (RightCoercion t1) = do
- exp1 <- expand t1
- return $ RightCoercion exp1
- expapp (t@(Tcon (m,tc))) ts =
- do env <- mlookupM tsenv_ tsenv eempty m
- case elookup env tc of
- Just (formals,rhs) | (length formals) == (length ts) ->
- return (substl formals ts rhs)
- _ -> return (foldl Tapp t ts)
- expapp (Tapp t1 t2) ts =
- do t2' <- expand t2
- expapp t1 (t2':ts)
- expapp t ts =
- do t' <- expand t
- return (foldl Tapp t' ts)
+ ch (InstCoercion ty arg) = do
+ forallK <- checkTyCo es ty
+ case forallK of
+ ((Tforall (v1,k1) b1), (Tforall (v2,k2) b2)) -> do
+ require (k1 `eqKind` k2) ("Kind mismatch in argument of inst: "
+ ++ show ty)
+ argK <- checkTy es arg
+ require (argK `eqKind` k1) ("Kind mismatch in type being "
+ ++ "instantiated: " ++ show arg)
+ let newLhs = substl [v1] [arg] b1
+ let newRhs = substl [v2] [arg] b2
+ return $ Keq newLhs newRhs
+ _ -> fail ("Non-forall-ty in argument to inst: " ++ show ty)
+
+checkTyCo :: (Tcenv, Tvenv) -> Ty -> CheckResult (Ty, Ty)
+checkTyCo es@(tcenv,_) t@(Tapp t1 t2) =
+ (case splitTyConApp_maybe t of
+ Just (tc, tys) -> do
+ tcK <- qlookupM tcenv_ tcenv eempty tc
+ case tcK of
+ -- todo: avoid duplicating this code
+ -- blah, this almost calls for a different syntactic form
+ -- (for a defined-coercion app): (TCoercionApp Tcon [Ty])
+ Coercion (DefinedCoercion tbs (from, to)) -> do
+ require (length tys == length tbs) $
+ ("Arity mismatch in coercion app: " ++ show t)
+ let (tvs, tks) = unzip tbs
+ argKs <- mapM (checkTy es) tys
+ let kPairs = zip argKs tks
+ let kindsOk = all (uncurry subKindOf) kPairs
+ require kindsOk
+ ("Kind mismatch in coercion app: " ++ show tks
+ ++ " and " ++ show argKs ++ " t = " ++ show t)
+ return (substl tvs tys from, substl tvs tys to)
+ _ -> checkTapp t1 t2
+ _ -> checkTapp t1 t2)
+ where checkTapp t1 t2 = do
+ (lhsRator, rhsRator) <- checkTyCo es t1
+ (lhs, rhs) <- checkTyCo es t2
+ -- Comp rule from paper
+ checkTy es (Tapp lhsRator lhs)
+ checkTy es (Tapp rhsRator rhs)
+ return (Tapp lhsRator lhs, Tapp rhsRator rhs)
+checkTyCo (tcenv, tvenv) (Tforall tb t) = do
+ tvenv' <- extendTvenv tvenv tb
+ (t1,t2) <- checkTyCo (tcenv, tvenv') t
+ return (Tforall tb t1, Tforall tb t2)
+checkTyCo es t = do
+ k <- checkTy es t
+ case k of
+ Keq t1 t2 -> return (t1, t2)
+ -- otherwise, expand by the "refl" rule
+ _ -> return (t, t)
mlookupM :: (Eq a, Show a) => (Envs -> Env a b) -> Env a b -> Env a b -> Mname
-> CheckResult (Env a b)
UnsafeCoercion t1 t2 -> UnsafeCoercion (f env t1) (f env t2)
LeftCoercion t1 -> LeftCoercion (f env t1)
RightCoercion t1 -> RightCoercion (f env t1)
+ InstCoercion t1 t2 -> InstCoercion (f env t1) (f env t2)
where free = foldr union [] (map (freeTvars.snd) env)
t' = freshTvar free
freeTvars :: Ty -> [Tvar]
freeTvars (Tcon _) = []
freeTvars (Tvar v) = [v]
-freeTvars (Tapp t1 t2) = (freeTvars t1) `union` (freeTvars t2)
+freeTvars (Tapp t1 t2) = freeTvars t1 `union` freeTvars t2
freeTvars (Tforall (t,_) t1) = delete t (freeTvars t1)
freeTvars (TransCoercion t1 t2) = freeTvars t1 `union` freeTvars t2
freeTvars (SymCoercion t) = freeTvars t
freeTvars (UnsafeCoercion t1 t2) = freeTvars t1 `union` freeTvars t2
freeTvars (LeftCoercion t) = freeTvars t
freeTvars (RightCoercion t) = freeTvars t
+freeTvars (InstCoercion t1 t2) = freeTvars t1 `union` freeTvars t2
{- Return any tvar *not* in the argument list. -}
freshTvar :: [Tvar] -> Tvar
reportError :: Show a => a -> String -> b
reportError e s = error $ ("Core type error: checkExpr failed with "
++ s ++ " and " ++ show e)
-
-warn :: String -> CheckResult ()
-warn s = (unsafePerformIO $ putStrLn ("WARNING: " ++ s)) `seq` return ()
\ No newline at end of file
projects / ghc-hetmet.git / blobdiff