git.iko.soy/rowtype-yoga/purescript-native
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rowtype-yoga/purescript-native/src/Language/PureScript/TypeChecker.hs
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1{-# LANGUAGE FlexibleInstances #-}
3-- |
4-- The top-level type checker, which checks all declarations in a module.
5--
6module Language.PureScript.TypeChecker
7 ( module T
8 , typeCheckModule
9 ) where
11import Prelude.Compat
13import Control.Monad (when, unless, void, forM, forM_)
14import Control.Monad.Error.Class (MonadError(..))
15import Control.Monad.State.Class (MonadState(..), modify)
16import Control.Monad.Supply.Class (MonadSupply)
17import Control.Monad.Writer.Class (MonadWriter(..))
19import Data.Foldable (for_, traverse_)
20import Data.List (nub, nubBy, (\\), sort, group)
21import Data.Maybe
22import qualified Data.Map as M
24import Language.PureScript.AST
25import Language.PureScript.Crash
26import Language.PureScript.Environment
27import Language.PureScript.Errors
28import Language.PureScript.Kinds
29import Language.PureScript.Linter
30import Language.PureScript.Names
31import Language.PureScript.Traversals
32import Language.PureScript.TypeChecker.Kinds as T
33import Language.PureScript.TypeChecker.Monad as T
34import Language.PureScript.TypeChecker.Synonyms as T
35import Language.PureScript.TypeChecker.Types as T
36import Language.PureScript.TypeClassDictionaries
37import Language.PureScript.Types
39addDataType
40 :: (MonadState CheckState m, MonadError MultipleErrors m, MonadWriter MultipleErrors m)
41 => ModuleName
42 -> DataDeclType
43 -> ProperName 'TypeName
44 -> [(String, Maybe Kind)]
45 -> [(ProperName 'ConstructorName, [Type])]
46 -> Kind
47 -> m ()
48addDataType moduleName dtype name args dctors ctorKind = do
49 env <- getEnv
50 putEnv $ env { types = M.insert (Qualified (Just moduleName) name) (ctorKind, DataType args dctors) (types env) }
51 for_ dctors $ \(dctor, tys) ->
52 warnAndRethrow (addHint (ErrorInDataConstructor dctor)) $
53 addDataConstructor moduleName dtype name (map fst args) dctor tys
55addDataConstructor
56 :: (MonadState CheckState m, MonadError MultipleErrors m, MonadWriter MultipleErrors m)
57 => ModuleName
58 -> DataDeclType
59 -> ProperName 'TypeName
60 -> [String]
61 -> ProperName 'ConstructorName
62 -> [Type]
63 -> m ()
64addDataConstructor moduleName dtype name args dctor tys = do
65 env <- getEnv
66 traverse_ checkTypeSynonyms tys
67 let retTy = foldl TypeApp (TypeConstructor (Qualified (Just moduleName) name)) (map TypeVar args)
68 let dctorTy = foldr function retTy tys
69 let polyType = mkForAll args dctorTy
70 let fields = [Ident ("value" ++ show n) | n <- [0..(length tys - 1)]]
71 putEnv $ env { dataConstructors = M.insert (Qualified (Just moduleName) dctor) (dtype, name, polyType, fields) (dataConstructors env) }
73addTypeSynonym
74 :: (MonadState CheckState m, MonadError MultipleErrors m, MonadWriter MultipleErrors m)
75 => ModuleName
76 -> ProperName 'TypeName
77 -> [(String, Maybe Kind)]
78 -> Type
79 -> Kind
80 -> m ()
81addTypeSynonym moduleName name args ty kind = do
82 env <- getEnv
83 checkTypeSynonyms ty
84 putEnv $ env { types = M.insert (Qualified (Just moduleName) name) (kind, TypeSynonym) (types env)
85 , typeSynonyms = M.insert (Qualified (Just moduleName) name) (args, ty) (typeSynonyms env) }
87valueIsNotDefined
88 :: (MonadState CheckState m, MonadError MultipleErrors m, MonadWriter MultipleErrors m)
89 => ModuleName
90 -> Ident
91 -> m ()
92valueIsNotDefined moduleName name = do
93 env <- getEnv
94 case M.lookup (moduleName, name) (names env) of
95 Just _ -> throwError . errorMessage $ RedefinedIdent name
96 Nothing -> return ()
98addValue
99 :: (MonadState CheckState m, MonadError MultipleErrors m, MonadWriter MultipleErrors m)
100 => ModuleName
101 -> Ident
102 -> Type
103 -> NameKind
104 -> m ()
105addValue moduleName name ty nameKind = do
106 env <- getEnv
107 putEnv (env { names = M.insert (moduleName, name) (ty, nameKind, Defined) (names env) })
109addTypeClass
110 :: (MonadState CheckState m, MonadError MultipleErrors m, MonadWriter MultipleErrors m)
111 => ModuleName
112 -> ProperName 'ClassName
113 -> [(String, Maybe Kind)]
114 -> [Constraint]
115 -> [Declaration]
116 -> m ()
117addTypeClass moduleName pn args implies ds =
118 let members = map toPair ds in
119 modify $ \st -> st { checkEnv = (checkEnv st) { typeClasses = M.insert (Qualified (Just moduleName) pn) (args, members, implies) (typeClasses . checkEnv $ st) } }
120 where
121 toPair (TypeDeclaration ident ty) = (ident, ty)
122 toPair (PositionedDeclaration _ _ d) = toPair d
123 toPair _ = internalError "Invalid declaration in TypeClassDeclaration"
125addTypeClassDictionaries
126 :: (MonadState CheckState m, MonadError MultipleErrors m, MonadWriter MultipleErrors m)
127 => Maybe ModuleName
128 -> M.Map (Qualified (ProperName 'ClassName)) (M.Map (Qualified Ident) TypeClassDictionaryInScope)
129 -> m ()
130addTypeClassDictionaries mn entries =
131 modify $ \st -> st { checkEnv = (checkEnv st) { typeClassDictionaries = insertState st } }
132 where insertState st = M.insertWith (M.unionWith M.union) mn entries (typeClassDictionaries . checkEnv $ st)
134checkDuplicateTypeArguments
135 :: (MonadState CheckState m, MonadError MultipleErrors m, MonadWriter MultipleErrors m)
136 => [String]
137 -> m ()
138checkDuplicateTypeArguments args = for_ firstDup $ \dup ->
139 throwError . errorMessage $ DuplicateTypeArgument dup
140 where
141 firstDup :: Maybe String
142 firstDup = listToMaybe $ args \\ nub args
144checkTypeClassInstance
145 :: (MonadState CheckState m, MonadError MultipleErrors m, MonadWriter MultipleErrors m)
146 => ModuleName
147 -> Type
148 -> m ()
149checkTypeClassInstance _ (TypeVar _) = return ()
150checkTypeClassInstance _ (TypeConstructor ctor) = do
151 env <- getEnv
152 when (ctor `M.member` typeSynonyms env) . throwError . errorMessage $ TypeSynonymInstance
153 return ()
154checkTypeClassInstance m (TypeApp t1 t2) = checkTypeClassInstance m t1 >> checkTypeClassInstance m t2
155checkTypeClassInstance _ ty = throwError . errorMessage $ InvalidInstanceHead ty
157-- |
158-- Check that type synonyms are fully-applied in a type
159--
160checkTypeSynonyms
161 :: (MonadState CheckState m, MonadError MultipleErrors m, MonadWriter MultipleErrors m)
162 => Type
163 -> m ()
164checkTypeSynonyms = void . replaceAllTypeSynonyms
166-- |
167-- Type check all declarations in a module
168--
169-- At this point, many declarations will have been desugared, but it is still necessary to
170--
171-- * Kind-check all types and add them to the @Environment@
172--
173-- * Type-check all values and add them to the @Environment@
174--
175-- * Bring type class instances into scope
176--
177-- * Process module imports
178--
179typeCheckAll
180 :: forall m
181 . (MonadSupply m, MonadState CheckState m, MonadError MultipleErrors m, MonadWriter MultipleErrors m)
182 => ModuleName
183 -> [DeclarationRef]
184 -> [Declaration]
185 -> m [Declaration]
186typeCheckAll moduleName _ = traverse go
187 where
188 go :: Declaration -> m Declaration
189 go (DataDeclaration dtype name args dctors) = do
190 warnAndRethrow (addHint (ErrorInTypeConstructor name)) $ do
191 when (dtype == Newtype) $ checkNewtype name dctors
192 checkDuplicateTypeArguments $ map fst args
193 ctorKind <- kindsOf True moduleName name args (concatMap snd dctors)
194 let args' = args `withKinds` ctorKind
195 addDataType moduleName dtype name args' dctors ctorKind
196 return $ DataDeclaration dtype name args dctors
197 go (d@(DataBindingGroupDeclaration tys)) = do
198 warnAndRethrow (addHint ErrorInDataBindingGroup) $ do
199 let syns = mapMaybe toTypeSynonym tys
200 let dataDecls = mapMaybe toDataDecl tys
201 (syn_ks, data_ks) <- kindsOfAll moduleName syns (map (\(_, name, args, dctors) -> (name, args, concatMap snd dctors)) dataDecls)
202 for_ (zip dataDecls data_ks) $ \((dtype, name, args, dctors), ctorKind) -> do
203 when (dtype == Newtype) $ checkNewtype name dctors
204 checkDuplicateTypeArguments $ map fst args
205 let args' = args `withKinds` ctorKind
206 addDataType moduleName dtype name args' dctors ctorKind
207 for_ (zip syns syn_ks) $ \((name, args, ty), kind) -> do
208 checkDuplicateTypeArguments $ map fst args
209 let args' = args `withKinds` kind
210 addTypeSynonym moduleName name args' ty kind
211 return d
212 where
213 toTypeSynonym (TypeSynonymDeclaration nm args ty) = Just (nm, args, ty)
214 toTypeSynonym (PositionedDeclaration _ _ d') = toTypeSynonym d'
215 toTypeSynonym _ = Nothing
216 toDataDecl (DataDeclaration dtype nm args dctors) = Just (dtype, nm, args, dctors)
217 toDataDecl (PositionedDeclaration _ _ d') = toDataDecl d'
218 toDataDecl _ = Nothing
219 go (TypeSynonymDeclaration name args ty) = do
220 warnAndRethrow (addHint (ErrorInTypeSynonym name)) $ do
221 checkDuplicateTypeArguments $ map fst args
222 kind <- kindsOf False moduleName name args [ty]
223 let args' = args `withKinds` kind
224 addTypeSynonym moduleName name args' ty kind
225 return $ TypeSynonymDeclaration name args ty
226 go TypeDeclaration{} =
227 internalError "Type declarations should have been removed before typeCheckAlld"
228 go (ValueDeclaration name nameKind [] (Right val)) = do
229 env <- getEnv
230 warnAndRethrow (addHint (ErrorInValueDeclaration name)) $ do
231 val' <- checkExhaustiveExpr env moduleName val
232 valueIsNotDefined moduleName name
233 [(_, (val'', ty))] <- typesOf NonRecursiveBindingGroup moduleName [(name, val')]
234 addValue moduleName name ty nameKind
235 return $ ValueDeclaration name nameKind [] $ Right val''
236 go ValueDeclaration{} = internalError "Binders were not desugared"
237 go (BindingGroupDeclaration vals) = do
238 env <- getEnv
239 warnAndRethrow (addHint (ErrorInBindingGroup (map (\(ident, _, _) -> ident) vals))) $ do
240 for_ vals $ \(ident, _, _) ->
241 valueIsNotDefined moduleName ident
242 vals' <- mapM (thirdM (checkExhaustiveExpr env moduleName)) vals
243 tys <- typesOf RecursiveBindingGroup moduleName $ map (\(ident, _, ty) -> (ident, ty)) vals'
244 vals'' <- forM [ (name, val, nameKind, ty)
245 | (name, nameKind, _) <- vals'
246 , (name', (val, ty)) <- tys
247 , name == name'
248 ] $ \(name, val, nameKind, ty) -> do
249 addValue moduleName name ty nameKind
250 return (name, nameKind, val)
251 return $ BindingGroupDeclaration vals''
252 go (d@(ExternDataDeclaration name kind)) = do
253 env <- getEnv
254 putEnv $ env { types = M.insert (Qualified (Just moduleName) name) (kind, ExternData) (types env) }
255 return d
256 go (d@(ExternDeclaration name ty)) = do
257 warnAndRethrow (addHint (ErrorInForeignImport name)) $ do
258 env <- getEnv
259 kind <- kindOf ty
260 guardWith (errorMessage (ExpectedType ty kind)) $ kind == Star
261 case M.lookup (moduleName, name) (names env) of
262 Just _ -> throwError . errorMessage $ RedefinedIdent name
263 Nothing -> putEnv (env { names = M.insert (moduleName, name) (ty, External, Defined) (names env) })
264 return d
265 go d@FixityDeclaration{} = return d
266 go d@ImportDeclaration{} = return d
267 go d@(TypeClassDeclaration pn args implies tys) = do
268 addTypeClass moduleName pn args implies tys
269 return d
270 go (d@(TypeInstanceDeclaration dictName deps className tys body)) = rethrow (addHint (ErrorInInstance className tys)) $ do
271 traverse_ (checkTypeClassInstance moduleName) tys
272 forM_ deps $ traverse_ (checkTypeClassInstance moduleName) . constraintArgs
273 checkOrphanInstance dictName className tys
274 _ <- traverseTypeInstanceBody checkInstanceMembers body
275 let dict = TypeClassDictionaryInScope (Qualified (Just moduleName) dictName) [] className tys (Just deps)
276 addTypeClassDictionaries (Just moduleName) . M.singleton className $ M.singleton (tcdName dict) dict
277 return d
278 go (PositionedDeclaration pos com d) =
279 warnAndRethrowWithPosition pos $ PositionedDeclaration pos com <$> go d
281 checkInstanceMembers :: [Declaration] -> m [Declaration]
282 checkInstanceMembers instDecls = do
283 let idents = sort . map head . group . map memberName $ instDecls
284 for_ (firstDuplicate idents) $ \ident ->
285 throwError . errorMessage $ DuplicateValueDeclaration ident
286 return instDecls
287 where
288 memberName :: Declaration -> Ident
289 memberName (ValueDeclaration ident _ _ _) = ident
290 memberName (PositionedDeclaration _ _ d) = memberName d
291 memberName _ = internalError "checkInstanceMembers: Invalid declaration in type instance definition"
293 firstDuplicate :: (Eq a) => [a] -> Maybe a
294 firstDuplicate (x : xs@(y : _))
295 | x == y = Just x
296 | otherwise = firstDuplicate xs
297 firstDuplicate _ = Nothing
299 checkOrphanInstance :: Ident -> Qualified (ProperName 'ClassName) -> [Type] -> m ()
300 checkOrphanInstance dictName className@(Qualified (Just mn') _) tys'
301 | moduleName == mn' || any checkType tys' = return ()
302 | otherwise = throwError . errorMessage $ OrphanInstance dictName className tys'
303 where
304 checkType :: Type -> Bool
305 checkType (TypeVar _) = False
306 checkType (TypeConstructor (Qualified (Just mn'') _)) = moduleName == mn''
307 checkType (TypeConstructor (Qualified Nothing _)) = internalError "Unqualified type name in checkOrphanInstance"
308 checkType (TypeApp t1 _) = checkType t1
309 checkType _ = internalError "Invalid type in instance in checkOrphanInstance"
310 checkOrphanInstance _ _ _ = internalError "Unqualified class name in checkOrphanInstance"
312 checkNewtype :: ProperName 'TypeName -> [(ProperName 'ConstructorName, [Type])] -> m ()
313 checkNewtype _ [(_, [_])] = return ()
314 checkNewtype name _ = throwError . errorMessage $ InvalidNewtype name
316 -- |
317 -- This function adds the argument kinds for a type constructor so that they may appear in the externs file,
318 -- extracted from the kind of the type constructor itself.
319 --
320 withKinds :: [(String, Maybe Kind)] -> Kind -> [(String, Maybe Kind)]
321 withKinds [] _ = []
322 withKinds (s@(_, Just _ ):ss) (FunKind _ k) = s : withKinds ss k
323 withKinds ( (s, Nothing):ss) (FunKind k1 k2) = (s, Just k1) : withKinds ss k2
324 withKinds _ _ = internalError "Invalid arguments to peelKinds"
326-- |
327-- Type check an entire module and ensure all types and classes defined within the module that are
328-- required by exported members are also exported.
329--
330typeCheckModule
331 :: forall m
332 . (MonadSupply m, MonadState CheckState m, MonadError MultipleErrors m, MonadWriter MultipleErrors m)
333 => Module
334 -> m Module
335typeCheckModule (Module _ _ _ _ Nothing) =
336 internalError "exports should have been elaborated before typeCheckModule"
337typeCheckModule (Module ss coms mn decls (Just exps)) =
338 warnAndRethrow (addHint (ErrorInModule mn)) $ do
339 modify (\s -> s { checkCurrentModule = Just mn })
340 decls' <- typeCheckAll mn exps decls
341 for_ exps $ \e -> do
342 checkTypesAreExported e
343 checkClassMembersAreExported e
344 checkClassesAreExported e
345 return $ Module ss coms mn decls' (Just exps)
346 where
348 checkMemberExport :: (Type -> [DeclarationRef]) -> DeclarationRef -> m ()
349 checkMemberExport extract dr@(TypeRef name dctors) = do
350 env <- getEnv
351 case M.lookup (Qualified (Just mn) name) (typeSynonyms env) of
352 Nothing -> return ()
353 Just (_, ty) -> checkExport dr extract ty
354 case dctors of
355 Nothing -> return ()
356 Just dctors' -> for_ dctors' $ \dctor ->
357 case M.lookup (Qualified (Just mn) dctor) (dataConstructors env) of
358 Nothing -> return ()
359 Just (_, _, ty, _) -> checkExport dr extract ty
360 return ()
361 checkMemberExport extract dr@(ValueRef name) = do
362 ty <- lookupVariable mn (Qualified (Just mn) name)
363 checkExport dr extract ty
364 checkMemberExport _ _ = return ()
366 checkExport :: DeclarationRef -> (Type -> [DeclarationRef]) -> Type -> m ()
367 checkExport dr extract ty = case filter (not . exported) (extract ty) of
368 [] -> return ()
369 hidden -> throwError . errorMessage $ TransitiveExportError dr (nubBy nubEq hidden)
370 where
371 exported e = any (exports e) exps
372 exports (TypeRef pn1 _) (TypeRef pn2 _) = pn1 == pn2
373 exports (ValueRef id1) (ValueRef id2) = id1 == id2
374 exports (TypeClassRef pn1) (TypeClassRef pn2) = pn1 == pn2
375 exports (PositionedDeclarationRef _ _ r1) r2 = exports r1 r2
376 exports r1 (PositionedDeclarationRef _ _ r2) = exports r1 r2
377 exports _ _ = False
378 -- We avoid Eq for `nub`bing as the dctor part of `TypeRef` evaluates to
379 -- `error` for the values generated here (we don't need them anyway)
380 nubEq (TypeRef pn1 _) (TypeRef pn2 _) = pn1 == pn2
381 nubEq r1 r2 = r1 == r2
384 -- Check that all the type constructors defined in the current module that appear in member types
385 -- have also been exported from the module
386 checkTypesAreExported :: DeclarationRef -> m ()
387 checkTypesAreExported = checkMemberExport findTcons
388 where
389 findTcons :: Type -> [DeclarationRef]
390 findTcons = everythingOnTypes (++) go
391 where
392 go (TypeConstructor (Qualified (Just mn') name)) | mn' == mn = [TypeRef name (internalError "Data constructors unused in checkTypesAreExported")]
393 go _ = []
395 -- Check that all the classes defined in the current module that appear in member types have also
396 -- been exported from the module
397 checkClassesAreExported :: DeclarationRef -> m ()
398 checkClassesAreExported = checkMemberExport findClasses
399 where
400 findClasses :: Type -> [DeclarationRef]
401 findClasses = everythingOnTypes (++) go
402 where
403 go (ConstrainedType cs _) = mapMaybe (fmap TypeClassRef . extractCurrentModuleClass . constraintClass) cs
404 go _ = []
405 extractCurrentModuleClass :: Qualified (ProperName 'ClassName) -> Maybe (ProperName 'ClassName)
406 extractCurrentModuleClass (Qualified (Just mn') name) | mn == mn' = Just name
407 extractCurrentModuleClass _ = Nothing
409 checkClassMembersAreExported :: DeclarationRef -> m ()
410 checkClassMembersAreExported dr@(TypeClassRef name) = do
411 let members = ValueRef `map` head (mapMaybe findClassMembers decls)
412 let missingMembers = members \\ exps
413 unless (null missingMembers) $ throwError . errorMessage $ TransitiveExportError dr members
414 where
415 findClassMembers :: Declaration -> Maybe [Ident]
416 findClassMembers (TypeClassDeclaration name' _ _ ds) | name == name' = Just $ map extractMemberName ds
417 findClassMembers (PositionedDeclaration _ _ d) = findClassMembers d
418 findClassMembers _ = Nothing
419 extractMemberName :: Declaration -> Ident
420 extractMemberName (PositionedDeclaration _ _ d) = extractMemberName d
421 extractMemberName (TypeDeclaration memberName _) = memberName
422 extractMemberName _ = internalError "Unexpected declaration in typeclass member list"
423 checkClassMembersAreExported _ = return ()