module Language.PureScript.TypeChecker (
module T,
typeCheckModule
) where
import Language.PureScript.TypeChecker.Monad as T
import Language.PureScript.TypeChecker.Kinds as T
import Language.PureScript.TypeChecker.Types as T
import Language.PureScript.TypeChecker.Synonyms as T
import Data.Maybe
import Data.List (nub, (\\))
import Data.Foldable (for_)
import qualified Data.Map as M
import Control.Monad.State
import Control.Monad.Except
import Language.PureScript.Types
import Language.PureScript.Names
import Language.PureScript.Kinds
import Language.PureScript.AST
import Language.PureScript.TypeClassDictionaries
import Language.PureScript.Environment
import Language.PureScript.Errors
addDataType :: ModuleName -> DataDeclType -> ProperName -> [(String, Maybe Kind)] -> [(ProperName, [Type])] -> Kind -> Check ()
addDataType moduleName dtype name args dctors ctorKind = do
env <- getEnv
putEnv $ env { types = M.insert (Qualified (Just moduleName) name) (ctorKind, DataType args dctors) (types env) }
forM_ dctors $ \(dctor, tys) ->
rethrow (onErrorMessages (ErrorInDataConstructor dctor)) $
addDataConstructor moduleName dtype name (map fst args) dctor tys
addDataConstructor :: ModuleName -> DataDeclType -> ProperName -> [String] -> ProperName -> [Type] -> Check ()
addDataConstructor moduleName dtype name args dctor tys = do
env <- getEnv
mapM_ checkTypeSynonyms tys
let retTy = foldl TypeApp (TypeConstructor (Qualified (Just moduleName) name)) (map TypeVar args)
let dctorTy = foldr function retTy tys
let polyType = mkForAll args dctorTy
let fields = [Ident ("value" ++ show n) | n <- [0..(length tys 1)]]
putEnv $ env { dataConstructors = M.insert (Qualified (Just moduleName) dctor) (dtype, name, polyType, fields) (dataConstructors env) }
addTypeSynonym :: ModuleName -> ProperName -> [(String, Maybe Kind)] -> Type -> Kind -> Check ()
addTypeSynonym moduleName name args ty kind = do
env <- getEnv
checkTypeSynonyms ty
putEnv $ env { types = M.insert (Qualified (Just moduleName) name) (kind, TypeSynonym) (types env)
, typeSynonyms = M.insert (Qualified (Just moduleName) name) (args, ty) (typeSynonyms env) }
valueIsNotDefined :: ModuleName -> Ident -> Check ()
valueIsNotDefined moduleName name = do
env <- getEnv
case M.lookup (moduleName, name) (names env) of
Just _ -> throwError . errorMessage $ RedefinedIdent name
Nothing -> return ()
addValue :: ModuleName -> Ident -> Type -> NameKind -> Check ()
addValue moduleName name ty nameKind = do
env <- getEnv
putEnv (env { names = M.insert (moduleName, name) (ty, nameKind, Defined) (names env) })
addTypeClass :: ModuleName -> ProperName -> [(String, Maybe Kind)] -> [Constraint] -> [Declaration] -> Check ()
addTypeClass moduleName pn args implies ds =
let members = map toPair ds in
modify $ \st -> st { checkEnv = (checkEnv st) { typeClasses = M.insert (Qualified (Just moduleName) pn) (args, members, implies) (typeClasses . checkEnv $ st) } }
where
toPair (TypeDeclaration ident ty) = (ident, ty)
toPair (PositionedDeclaration _ _ d) = toPair d
toPair _ = error "Invalid declaration in TypeClassDeclaration"
addTypeClassDictionaries :: [TypeClassDictionaryInScope] -> Check ()
addTypeClassDictionaries entries =
let mentries = M.fromList [ ((canonicalizeDictionary entry, mn), entry) | entry@TypeClassDictionaryInScope{ tcdName = Qualified mn _ } <- entries ]
in modify $ \st -> st { checkEnv = (checkEnv st) { typeClassDictionaries = (typeClassDictionaries . checkEnv $ st) `M.union` mentries } }
checkDuplicateTypeArguments :: [String] -> Check ()
checkDuplicateTypeArguments args = for_ firstDup $ \dup ->
throwError . errorMessage $ DuplicateTypeArgument dup
where
firstDup :: Maybe String
firstDup = listToMaybe $ args \\ nub args
checkTypeClassInstance :: ModuleName -> Type -> Check ()
checkTypeClassInstance _ (TypeVar _) = return ()
checkTypeClassInstance _ (TypeConstructor ctor) = do
env <- getEnv
when (ctor `M.member` typeSynonyms env) . throwError . errorMessage $ TypeSynonymInstance
return ()
checkTypeClassInstance m (TypeApp t1 t2) = checkTypeClassInstance m t1 >> checkTypeClassInstance m t2
checkTypeClassInstance _ ty = throwError . errorMessage $ InvalidInstanceHead ty
checkTypeSynonyms :: Type -> Check ()
checkTypeSynonyms = void . replaceAllTypeSynonyms
typeCheckAll :: Maybe ModuleName -> ModuleName -> [DeclarationRef] -> [Declaration] -> Check [Declaration]
typeCheckAll mainModuleName moduleName exps = go
where
go :: [Declaration] -> Check [Declaration]
go [] = return []
go (DataDeclaration dtype name args dctors : rest) = do
rethrow (onErrorMessages (ErrorInTypeConstructor name)) $ do
when (dtype == Newtype) $ checkNewtype dctors
checkDuplicateTypeArguments $ map fst args
ctorKind <- kindsOf True moduleName name args (concatMap snd dctors)
let args' = args `withKinds` ctorKind
addDataType moduleName dtype name args' dctors ctorKind
ds <- go rest
return $ DataDeclaration dtype name args dctors : ds
where
checkNewtype :: [(ProperName, [Type])] -> Check ()
checkNewtype [(_, [_])] = return ()
checkNewtype [(_, _)] = throwError . errorMessage $ InvalidNewtype
checkNewtype _ = throwError . errorMessage $ InvalidNewtype
go (d@(DataBindingGroupDeclaration tys) : rest) = do
rethrow (onErrorMessages ErrorInDataBindingGroup) $ do
let syns = mapMaybe toTypeSynonym tys
let dataDecls = mapMaybe toDataDecl tys
(syn_ks, data_ks) <- kindsOfAll moduleName syns (map (\(_, name, args, dctors) -> (name, args, concatMap snd dctors)) dataDecls)
forM_ (zip dataDecls data_ks) $ \((dtype, name, args, dctors), ctorKind) -> do
checkDuplicateTypeArguments $ map fst args
let args' = args `withKinds` ctorKind
addDataType moduleName dtype name args' dctors ctorKind
forM_ (zip syns syn_ks) $ \((name, args, ty), kind) -> do
checkDuplicateTypeArguments $ map fst args
let args' = args `withKinds` kind
addTypeSynonym moduleName name args' ty kind
ds <- go rest
return $ d : ds
where
toTypeSynonym (TypeSynonymDeclaration nm args ty) = Just (nm, args, ty)
toTypeSynonym (PositionedDeclaration _ _ d') = toTypeSynonym d'
toTypeSynonym _ = Nothing
toDataDecl (DataDeclaration dtype nm args dctors) = Just (dtype, nm, args, dctors)
toDataDecl (PositionedDeclaration _ _ d') = toDataDecl d'
toDataDecl _ = Nothing
go (TypeSynonymDeclaration name args ty : rest) = do
rethrow (onErrorMessages (ErrorInTypeSynonym name)) $ do
checkDuplicateTypeArguments $ map fst args
kind <- kindsOf False moduleName name args [ty]
let args' = args `withKinds` kind
addTypeSynonym moduleName name args' ty kind
ds <- go rest
return $ TypeSynonymDeclaration name args ty : ds
go (TypeDeclaration _ _ : _) = error "Type declarations should have been removed"
go (ValueDeclaration name nameKind [] (Right val) : rest) = do
d <- rethrow (onErrorMessages (ErrorInValueDeclaration name)) $ do
valueIsNotDefined moduleName name
[(_, (val', ty))] <- typesOf mainModuleName moduleName [(name, val)]
addValue moduleName name ty nameKind
return $ ValueDeclaration name nameKind [] $ Right val'
ds <- go rest
return $ d : ds
go (ValueDeclaration{} : _) = error "Binders were not desugared"
go (BindingGroupDeclaration vals : rest) = do
d <- rethrow (onErrorMessages (ErrorInBindingGroup (map (\(ident, _, _) -> ident) vals))) $ do
forM_ (map (\(ident, _, _) -> ident) vals) $ \name ->
valueIsNotDefined moduleName name
tys <- typesOf mainModuleName moduleName $ map (\(ident, _, ty) -> (ident, ty)) vals
vals' <- forM [ (name, val, nameKind, ty)
| (name, nameKind, _) <- vals
, (name', (val, ty)) <- tys
, name == name'
] $ \(name, val, nameKind, ty) -> do
addValue moduleName name ty nameKind
return (name, nameKind, val)
return $ BindingGroupDeclaration vals'
ds <- go rest
return $ d : ds
go (d@(ExternDataDeclaration name kind) : rest) = do
env <- getEnv
putEnv $ env { types = M.insert (Qualified (Just moduleName) name) (kind, ExternData) (types env) }
ds <- go rest
return $ d : ds
go (d@(ExternDeclaration importTy name _ ty) : rest) = do
rethrow (onErrorMessages (ErrorInForeignImport name)) $ do
env <- getEnv
kind <- kindOf moduleName ty
guardWith (errorMessage (ExpectedType kind)) $ kind == Star
case M.lookup (moduleName, name) (names env) of
Just _ -> throwError . errorMessage $ RedefinedIdent name
Nothing -> putEnv (env { names = M.insert (moduleName, name) (ty, Extern importTy, Defined) (names env) })
ds <- go rest
return $ d : ds
go (d@(FixityDeclaration _ name) : rest) = do
ds <- go rest
env <- getEnv
guardWith (errorMessage (OrphanFixityDeclaration name)) $ M.member (moduleName, Op name) $ names env
return $ d : ds
go (d@(ImportDeclaration importedModule _ _) : rest) = do
tcds <- getTypeClassDictionaries
let instances = filter (\tcd -> let Qualified (Just mn) _ = tcdName tcd in importedModule == mn) tcds
addTypeClassDictionaries [ tcd { tcdName = Qualified (Just moduleName) ident, tcdType = TCDAlias (canonicalizeDictionary tcd) }
| tcd <- instances
, tcdExported tcd
, let (Qualified _ ident) = tcdName tcd
]
ds <- go rest
return $ d : ds
go (d@(TypeClassDeclaration pn args implies tys) : rest) = do
addTypeClass moduleName pn args implies tys
ds <- go rest
return $ d : ds
go (d@(TypeInstanceDeclaration dictName deps className tys _) : rest) = do
goInstance d dictName deps className tys rest
go (d@(ExternInstanceDeclaration dictName deps className tys) : rest) = do
goInstance d dictName deps className tys rest
go (PositionedDeclaration pos com d : rest) =
rethrowWithPosition pos $ do
(d' : rest') <- go (d : rest)
return (PositionedDeclaration pos com d' : rest')
goInstance :: Declaration -> Ident -> [Constraint] -> Qualified ProperName -> [Type] -> [Declaration] -> Check [Declaration]
goInstance d dictName deps className tys rest = do
mapM_ (checkTypeClassInstance moduleName) tys
forM_ deps $ mapM_ (checkTypeClassInstance moduleName) . snd
addTypeClassDictionaries [TypeClassDictionaryInScope (Qualified (Just moduleName) dictName) className tys (Just deps) TCDRegular isInstanceExported]
ds <- go rest
return $ d : ds
where
isInstanceExported :: Bool
isInstanceExported = any exportsInstance exps
exportsInstance :: DeclarationRef -> Bool
exportsInstance (TypeInstanceRef name) | name == dictName = True
exportsInstance (PositionedDeclarationRef _ _ r) = exportsInstance r
exportsInstance _ = False
withKinds :: [(String, Maybe Kind)] -> Kind -> [(String, Maybe Kind)]
withKinds [] _ = []
withKinds (s@(_, Just _ ):ss) (FunKind _ k) = s : withKinds ss k
withKinds ( (s, Nothing):ss) (FunKind k1 k2) = (s, Just k1) : withKinds ss k2
withKinds _ _ = error "Invalid arguments to peelKinds"
typeCheckModule :: Maybe ModuleName -> Module -> Check Module
typeCheckModule _ (Module _ _ _ Nothing) = error "exports should have been elaborated"
typeCheckModule mainModuleName (Module coms mn decls (Just exps)) = rethrow (onErrorMessages (ErrorInModule mn)) $ do
modify (\s -> s { checkCurrentModule = Just mn })
decls' <- typeCheckAll mainModuleName mn exps decls
forM_ exps $ \e -> do
checkTypesAreExported e
checkClassMembersAreExported e
checkClassesAreExported e
return $ Module coms mn decls' (Just exps)
where
checkMemberExport :: (Type -> [DeclarationRef]) -> DeclarationRef -> Check ()
checkMemberExport extract dr@(ValueRef name) = do
ty <- lookupVariable mn (Qualified (Just mn) name)
case filter (not . exported) (extract ty) of
[] -> return ()
hidden -> throwError . errorMessage $ TransitiveExportError dr hidden
where
exported e = any (exports e) exps
exports (TypeRef pn1 _) (TypeRef pn2 _) = pn1 == pn2
exports (ValueRef id1) (ValueRef id2) = id1 == id2
exports (TypeClassRef pn1) (TypeClassRef pn2) = pn1 == pn2
exports (TypeInstanceRef id1) (TypeInstanceRef id2) = id1 == id2
exports (PositionedDeclarationRef _ _ r1) r2 = exports r1 r2
exports r1 (PositionedDeclarationRef _ _ r2) = exports r1 r2
exports _ _ = False
checkMemberExport _ _ = return ()
checkTypesAreExported :: DeclarationRef -> Check ()
checkTypesAreExported = checkMemberExport findTcons
where
findTcons :: Type -> [DeclarationRef]
findTcons = everythingOnTypes (++) go
where
go (TypeConstructor (Qualified (Just mn') name)) | mn' == mn = [TypeRef name (error "Data constructors unused in checkTypesAreExported")]
go _ = []
checkClassesAreExported :: DeclarationRef -> Check ()
checkClassesAreExported = checkMemberExport findClasses
where
findClasses :: Type -> [DeclarationRef]
findClasses = everythingOnTypes (++) go
where
go (ConstrainedType cs _) = mapMaybe (fmap TypeClassRef . extractCurrentModuleClass . fst) cs
go _ = []
extractCurrentModuleClass :: Qualified ProperName -> Maybe ProperName
extractCurrentModuleClass (Qualified (Just mn') name) | mn == mn' = Just name
extractCurrentModuleClass _ = Nothing
checkClassMembersAreExported :: DeclarationRef -> Check ()
checkClassMembersAreExported dr@(TypeClassRef name) = do
let members = ValueRef `map` head (mapMaybe findClassMembers decls)
let missingMembers = members \\ exps
unless (null missingMembers) $ throwError . errorMessage $ TransitiveExportError dr members
where
findClassMembers :: Declaration -> Maybe [Ident]
findClassMembers (TypeClassDeclaration name' _ _ ds) | name == name' = Just $ map extractMemberName ds
findClassMembers (PositionedDeclaration _ _ d) = findClassMembers d
findClassMembers _ = Nothing
extractMemberName :: Declaration -> Ident
extractMemberName (PositionedDeclaration _ _ d) = extractMemberName d
extractMemberName (TypeDeclaration memberName _) = memberName
extractMemberName _ = error "Unexpected declaration in typeclass member list"
checkClassMembersAreExported _ = return ()