extractHsTyRdrTyVars,
extractHsRhoRdrTyVars, extractGenericPatTyVars,
- mkHsOpApp, mkClassDecl,
+ mkHsOpApp, mkClassDecl,
mkHsNegApp, mkHsIntegral, mkHsFractional,
mkHsDo, mkHsSplice,
mkTyData, mkPrefixCon, mkRecCon, mkInlineSpec,
checkContext, -- HsType -> P HsContext
checkPred, -- HsType -> P HsPred
checkTyClHdr, -- LHsContext RdrName -> LHsType RdrName -> P (LHsContext RdrName, Located RdrName, [LHsTyVarBndr RdrName])
+ checkTyVars, -- [LHsType RdrName] -> P ()
checkSynHdr, -- LHsType RdrName -> P (Located RdrName, [LHsTyVarBndr RdrName])
+ checkTopTyClD, -- LTyClDecl RdrName -> P (HsDecl RdrName)
checkInstType, -- HsType -> P HsType
checkPattern, -- HsExp -> P HsPat
checkPatterns, -- SrcLoc -> [HsExp] -> P [HsPat]
= ClassDecl { tcdCtxt = cxt, tcdLName = cname, tcdTyVars = tyvars,
tcdFDs = fds,
tcdSigs = sigs,
- tcdMeths = mbinds
+ tcdMeths = mbinds,
+ tcdATs = ats
}
-mkTyData new_or_data (context, tname, tyvars) ksig data_cons maybe_deriv
+mkTyData new_or_data (context, tname, tyvars, typats) ksig data_cons maybe_deriv
= TyData { tcdND = new_or_data, tcdCtxt = context, tcdLName = tname,
- tcdTyVars = tyvars, tcdCons = data_cons,
+ tcdTyVars = tyvars, tcdTyPats = typats, tcdCons = data_cons,
tcdKindSig = ksig, tcdDerivs = maybe_deriv }
\end{code}
where (L l' b', ds') = getMonoBind (L l b) ds
go (d : ds) = d : go ds
+-- Declaration list may only contain value bindings and signatures
+--
cvBindGroup :: OrdList (LHsDecl RdrName) -> HsValBinds RdrName
cvBindGroup binding
- = case (cvBindsAndSigs binding) of { (mbs, sigs) ->
- ValBindsIn mbs sigs
- }
+ = case cvBindsAndSigs binding of
+ (mbs, sigs, []) -> -- list of type decls *always* empty
+ ValBindsIn mbs sigs
cvBindsAndSigs :: OrdList (LHsDecl RdrName)
- -> (Bag (LHsBind RdrName), [LSig RdrName])
+ -> (Bag (LHsBind RdrName), [LSig RdrName], [LTyClDecl RdrName])
-- Input decls contain just value bindings and signatures
+-- and in case of class or instance declarations also
+-- associated data or synonym definitions
cvBindsAndSigs fb = go (fromOL fb)
where
- go [] = (emptyBag, [])
- go (L l (SigD s) : ds) = (bs, L l s : ss)
- where (bs,ss) = go ds
- go (L l (ValD b) : ds) = (b' `consBag` bs, ss)
- where (b',ds') = getMonoBind (L l b) ds
- (bs,ss) = go ds'
+ go [] = (emptyBag, [], [])
+ go (L l (SigD s) : ds) = (bs, L l s : ss, ts)
+ where (bs, ss, ts) = go ds
+ go (L l (ValD b) : ds) = (b' `consBag` bs, ss, ts)
+ where (b', ds') = getMonoBind (L l b) ds
+ (bs, ss, ts) = go ds'
+ go (L l (TyClD t): ds) = (bs, ss, L l t : ts)
+ where (bs, ss, ts) = go ds
-----------------------------------------------------------------------------
-- Group function bindings into equation groups
ty -> do dict_ty <- checkDictTy (L l ty)
return (L l (HsForAllTy Implicit [] (noLoc []) dict_ty))
-checkTyVars :: [LHsType RdrName] -> P [LHsTyVarBndr RdrName]
-checkTyVars tvs
- = mapM chk tvs
+-- Check that the given list of type parameters are all type variables
+-- (possibly with a kind signature).
+--
+checkTyVars :: [LHsType RdrName] -> P ()
+checkTyVars tvs = mapM_ chk tvs
where
- -- Check that the name space is correct!
+ -- Check that the name space is correct!
chk (L l (HsKindSig (L _ (HsTyVar tv)) k))
- | isRdrTyVar tv = return (L l (KindedTyVar tv k))
+ | isRdrTyVar tv = return ()
chk (L l (HsTyVar tv))
- | isRdrTyVar tv = return (L l (UserTyVar tv))
+ | isRdrTyVar tv = return ()
chk (L l other)
= parseError l "Type found where type variable expected"
checkSynHdr :: LHsType RdrName -> P (Located RdrName, [LHsTyVarBndr RdrName])
-checkSynHdr ty = do { (_, tc, tvs) <- checkTyClHdr (noLoc []) ty
+checkSynHdr ty = do { (_, tc, tvs, Just tparms) <- checkTyClHdr (noLoc []) ty
+ ; checkTyVars tparms
; return (tc, tvs) }
checkTyClHdr :: LHsContext RdrName -> LHsType RdrName
- -> P (LHsContext RdrName, Located RdrName, [LHsTyVarBndr RdrName])
+ -> P (LHsContext RdrName, -- the type context
+ Located RdrName, -- the head symbol (type or class name)
+ [LHsTyVarBndr RdrName], -- free variables of the non-context part
+ Maybe [LHsType RdrName]) -- parameters of head symbol; wrapped into
+ -- 'Maybe' for 'mkTyData'
-- The header of a type or class decl should look like
-- (C a, D b) => T a b
-- or T a b
-- or a + b
-- etc
+-- With associated types, we can also have non-variable parameters; ie,
+-- T Int [a]
+-- The unaltered parameter list is returned in the fourth component of the
+-- result. Eg, for
+-- T Int [a]
+-- we return
+-- ('()', 'T', ['a'], Just ['Int', '[a]'])
checkTyClHdr (L l cxt) ty
- = do (tc, tvs) <- gol ty []
+ = do (tc, tvs, parms) <- gol ty []
mapM_ chk_pred cxt
- return (L l cxt, tc, tvs)
+ return (L l cxt, tc, tvs, Just parms)
where
gol (L l ty) acc = go l ty acc
go l (HsTyVar tc) acc
- | not (isRdrTyVar tc) = checkTyVars acc >>= \ tvs ->
- return (L l tc, tvs)
- go l (HsOpTy t1 tc t2) acc = checkTyVars (t1:t2:acc) >>= \ tvs ->
- return (tc, tvs)
+ | not (isRdrTyVar tc) = do
+ tvs <- extractTyVars acc
+ return (L l tc, tvs, acc)
+ go l (HsOpTy t1 tc t2) acc = do
+ tvs <- extractTyVars (t1:t2:acc)
+ return (tc, tvs, acc)
go l (HsParTy ty) acc = gol ty acc
go l (HsAppTy t1 t2) acc = gol t1 (t2:acc)
- go l other acc = parseError l "Malformed LHS to type of class declaration"
+ go l other acc =
+ parseError l "Malformed head of type or class declaration"
-- The predicates in a type or class decl must all
-- be HsClassPs. They need not all be type variables,
chk_pred (L l _)
= parseError l "Malformed context in type or class declaration"
-
+-- Extract the type variables of a list of type parameters.
+--
+-- * Type arguments can be complex type terms (needed for associated type
+-- declarations).
+--
+extractTyVars :: [LHsType RdrName] -> P [LHsTyVarBndr RdrName]
+extractTyVars tvs = collects [] tvs
+ where
+ -- Collect all variables (1st arg serves as an accumulator)
+ collect tvs (L l (HsForAllTy _ _ _ _)) =
+ parseError l "Forall type not allowed as type parameter"
+ collect tvs (L l (HsTyVar tv))
+ | isRdrTyVar tv = return $ L l (UserTyVar tv) : tvs
+ | otherwise = return tvs
+ collect tvs (L l (HsBangTy _ _ )) =
+ parseError l "Bang-style type annotations not allowed as type parameter"
+ collect tvs (L l (HsAppTy t1 t2 )) = do
+ tvs' <- collect tvs t2
+ collect tvs' t1
+ collect tvs (L l (HsFunTy t1 t2 )) = do
+ tvs' <- collect tvs t2
+ collect tvs' t1
+ collect tvs (L l (HsListTy t )) = collect tvs t
+ collect tvs (L l (HsPArrTy t )) = collect tvs t
+ collect tvs (L l (HsTupleTy _ ts )) = collects tvs ts
+ collect tvs (L l (HsOpTy t1 _ t2 )) = do
+ tvs' <- collect tvs t2
+ collect tvs' t1
+ collect tvs (L l (HsParTy t )) = collect tvs t
+ collect tvs (L l (HsNumTy t )) = return tvs
+ collect tvs (L l (HsPredTy t )) =
+ parseError l "Predicate not allowed as type parameter"
+ collect tvs (L l (HsKindSig (L _ (HsTyVar tv)) k))
+ | isRdrTyVar tv =
+ return $ L l (KindedTyVar tv k) : tvs
+ | otherwise =
+ parseError l "Kind signature only allowed for type variables"
+ collect tvs (L l (HsSpliceTy t )) =
+ parseError l "Splice not allowed as type parameter"
+
+ -- Collect all variables of a list of types
+ collects tvs [] = return tvs
+ collects tvs (t:ts) = do
+ tvs' <- collects tvs ts
+ collect tvs' t
+
+-- Wrap a toplevel type or class declaration into 'TyClDecl' after ensuring
+-- that all type parameters are variables only (which is in contrast to
+-- associated type declarations).
+--
+checkTopTyClD :: LTyClDecl RdrName -> P (HsDecl RdrName)
+checkTopTyClD (L _ d@TyData {tcdTyPats = Just typats}) =
+ do
+ checkTyVars typats
+ return $ TyClD d {tcdTyPats = Nothing}
+checkTopTyClD (L _ d) = return $ TyClD d
+
checkContext :: LHsType RdrName -> P (LHsContext RdrName)
checkContext (L l t)
= check t
-> Located (GRHSs RdrName)
-> P (HsBind RdrName)
+checkValDef lhs (Just sig) grhss
+ -- x :: ty = rhs parses as a *pattern* binding
+ = checkPatBind (L (combineLocs lhs sig) (ExprWithTySig lhs sig)) grhss
+
checkValDef lhs opt_sig grhss
= do { mb_fun <- isFunLhs lhs
; case mb_fun of
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