%
+% (c) The University of Glasgow 2006
% (c) The AQUA Project, Glasgow University, 1996-1998
%
-\section[TcTyClsDecls]{Typecheck type and class declarations}
+
+TcTyClsDecls: Typecheck type and class declarations
\begin{code}
module TcTyClsDecls (
#include "HsVersions.h"
-import HsSyn ( TyClDecl(..), HsConDetails(..), HsTyVarBndr(..),
- ConDecl(..), Sig(..), NewOrData(..), ResType(..),
- tyClDeclTyVars, isSynDecl, isClassDecl, isIdxTyDecl,
- isKindSigDecl, hsConArgs, LTyClDecl, tcdName,
- hsTyVarName, LHsTyVarBndr, LHsType
- )
-import HsTypes ( HsBang(..), getBangStrictness )
-import BasicTypes ( RecFlag(..), StrictnessMark(..) )
-import HscTypes ( implicitTyThings, ModDetails )
-import BuildTyCl ( buildClass, buildAlgTyCon, buildSynTyCon, buildDataCon,
- mkDataTyConRhs, mkNewTyConRhs )
+import HsSyn
+import HsTypes
+import BasicTypes
+import HscTypes
+import BuildTyCl
import TcRnMonad
-import TcEnv ( TyThing(..),
- tcLookupLocated, tcLookupLocatedGlobal,
- tcExtendGlobalEnv, tcExtendKindEnv, tcExtendKindEnvTvs,
- tcExtendRecEnv, tcLookupTyVar, InstInfo )
-import TcTyDecls ( calcRecFlags, calcClassCycles, calcSynCycles )
-import TcClassDcl ( tcClassSigs, tcAddDeclCtxt )
-import TcHsType ( kcHsTyVars, kcHsLiftedSigType, kcHsType,
- kcHsContext, tcTyVarBndrs, tcHsKindedType, tcHsKindedContext,
- kcHsSigType, tcHsBangType, tcLHsConResTy,
- tcDataKindSig, kcCheckHsType )
-import TcMType ( newKindVar, checkValidTheta, checkValidType,
- -- checkFreeness,
- UserTypeCtxt(..), SourceTyCtxt(..) )
-import TcType ( TcKind, TcType, Type, tyVarsOfType, mkPhiTy,
- mkArrowKind, liftedTypeKind, mkTyVarTys,
- tcSplitSigmaTy, tcEqTypes, tcGetTyVar_maybe )
-import Type ( PredType(..), splitTyConApp_maybe, mkTyVarTy,
- newTyConInstRhs, isLiftedTypeKind, Kind
- -- pprParendType, pprThetaArrow
- )
-import Generics ( validGenericMethodType, canDoGenerics )
-import Class ( Class, className, classTyCon, DefMeth(..), classBigSig, classTyVars )
-import TyCon ( TyCon, AlgTyConRhs( AbstractTyCon, OpenDataTyCon,
- OpenNewTyCon ),
- SynTyConRhs( OpenSynTyCon, SynonymTyCon ),
- tyConDataCons, mkForeignTyCon, isProductTyCon,
- isRecursiveTyCon, isOpenTyCon,
- tyConStupidTheta, synTyConRhs, isSynTyCon, tyConName,
- isNewTyCon, tyConKind )
-import DataCon ( DataCon, dataConUserType, dataConName,
- dataConFieldLabels, dataConTyCon, dataConAllTyVars,
- dataConFieldType, dataConResTys )
-import Var ( TyVar, idType, idName )
-import VarSet ( elemVarSet, mkVarSet )
-import Name ( Name, getSrcLoc )
+import TcEnv
+import TcTyDecls
+import TcClassDcl
+import TcHsType
+import TcMType
+import TcType
+import Type
+import Generics
+import Class
+import TyCon
+import DataCon
+import Var
+import VarSet
+import Name
+import OccName
import Outputable
-import Maybe ( isJust, fromJust, isNothing )
-import Maybes ( expectJust )
-import Unify ( tcMatchTys, tcMatchTyX )
-import Util ( zipLazy, isSingleton, notNull, sortLe )
-import List ( partition )
-import SrcLoc ( Located(..), unLoc, getLoc, srcLocSpan )
-import ListSetOps ( equivClasses, minusList )
-import List ( delete )
-import Digraph ( SCC(..) )
-import DynFlags ( DynFlag( Opt_GlasgowExts, Opt_Generics,
- Opt_UnboxStrictFields ) )
+import Maybes
+import Monad
+import Unify
+import Util
+import SrcLoc
+import ListSetOps
+import Digraph
+import DynFlags
+
+import Data.List ( partition, elemIndex )
\end{code}
; mod <- getModule
; traceTc (text "tcTyAndCl" <+> ppr mod)
; (syn_tycons, alg_tyclss) <- fixM (\ ~(rec_syn_tycons, rec_alg_tyclss) ->
- do { let { -- Calculate variances and rec-flag
+ do { let { -- Seperate ordinary synonyms from all other type and
+ -- class declarations and add all associated type
+ -- declarations from type classes. The latter is
+ -- required so that the temporary environment for the
+ -- knot includes all associated family declarations.
; (syn_decls, alg_decls) = partition (isSynDecl . unLoc)
- decls }
+ decls
+ ; alg_at_decls = concatMap addATs alg_decls
+ }
-- Extend the global env with the knot-tied results
-- for data types and classes
--
- -- We must populate the environment with the loop-tied T's right
- -- away, because the kind checker may "fault in" some type
- -- constructors that recursively mention T
- ; let { gbl_things = mkGlobalThings alg_decls rec_alg_tyclss }
+ -- We must populate the environment with the loop-tied
+ -- T's right away, because the kind checker may "fault
+ -- in" some type constructors that recursively
+ -- mention T
+ ; let gbl_things = mkGlobalThings alg_at_decls rec_alg_tyclss
; tcExtendRecEnv gbl_things $ do
-- Kind-check the declarations
{ (kc_syn_decls, kc_alg_decls) <- kcTyClDecls syn_decls alg_decls
- ; let { calc_rec = calcRecFlags boot_details rec_alg_tyclss
+ ; let { -- Calculate rec-flag
+ ; calc_rec = calcRecFlags boot_details rec_alg_tyclss
; tc_decl = addLocM (tcTyClDecl calc_rec) }
+
-- Type-check the type synonyms, and extend the envt
; syn_tycons <- tcSynDecls kc_syn_decls
; tcExtendGlobalEnv syn_tycons $ do
-- Type-check the data types and classes
{ alg_tyclss <- mappM tc_decl kc_alg_decls
- ; return (syn_tycons, alg_tyclss)
+ ; return (syn_tycons, concat alg_tyclss)
}}})
-- Finished with knot-tying now
-- Extend the environment with the finished things
-- Add the implicit things;
-- we want them in the environment because
-- they may be mentioned in interface files
+ -- NB: All associated types and their implicit things will be added a
+ -- second time here. This doesn't matter as the definitions are
+ -- the same.
; let { implicit_things = concatMap implicitTyThings alg_tyclss }
- ; traceTc ((text "Adding" <+> ppr alg_tyclss) $$ (text "and" <+> ppr implicit_things))
+ ; traceTc ((text "Adding" <+> ppr alg_tyclss)
+ $$ (text "and" <+> ppr implicit_things))
; tcExtendGlobalEnv implicit_things getGblEnv
}}
+ where
+ -- Pull associated types out of class declarations, to tie them into the
+ -- knot above.
+ -- NB: We put them in the same place in the list as `tcTyClDecl' will
+ -- eventually put the matching `TyThing's. That's crucial; otherwise,
+ -- the two argument lists of `mkGlobalThings' don't match up.
+ addATs decl@(L _ (ClassDecl {tcdATs = ats})) = decl : ats
+ addATs decl = [decl]
mkGlobalThings :: [LTyClDecl Name] -- The decls
-> [TyThing] -- Knot-tied, in 1-1 correspondence with the decls
data types (and GADTs).
\begin{code}
-tcIdxTyInstDecl :: LTyClDecl Name -> TcM (Maybe InstInfo) -- Nothing if error
+tcIdxTyInstDecl :: LTyClDecl Name -> TcM (Maybe TyThing) -- Nothing if error
tcIdxTyInstDecl (L loc decl)
= -- Prime error recovery, set source location
- recoverM (returnM Nothing) $
- setSrcSpan loc $
- tcAddDeclCtxt decl $
- do { -- indexed data types require -fglasgow-exts and can't be in an
+ recoverM (returnM Nothing) $
+ setSrcSpan loc $
+ tcAddDeclCtxt decl $
+ do { -- indexed data types require -findexed-types and can't be in an
-- hs-boot file
- ; gla_exts <- doptM Opt_GlasgowExts
+ ; gla_exts <- doptM Opt_IndexedTypes
; is_boot <- tcIsHsBoot -- Are we compiling an hs-boot file?
; checkTc gla_exts $ badIdxTyDecl (tcdLName decl)
; checkTc (not is_boot) $ badBootTyIdxDeclErr
; tcIdxTyInstDecl1 decl
}
-tcIdxTyInstDecl1 :: TyClDecl Name -> TcM (Maybe InstInfo) -- Nothing if error
+tcIdxTyInstDecl1 :: TyClDecl Name -> TcM (Maybe TyThing) -- Nothing if error
tcIdxTyInstDecl1 (decl@TySynonym {})
- = kcIdxTyPats decl $ \k_tvs k_typats resKind ->
- do { -- (1) kind check the right hand side of the type equation
+ = kcIdxTyPats decl $ \k_tvs k_typats resKind family ->
+ do { -- check that the family declaration is for a synonym
+ unless (isSynTyCon family) $
+ addErr (wrongKindOfFamily family)
+
+ ; -- (1) kind check the right hand side of the type equation
; k_rhs <- kcCheckHsType (tcdSynRhs decl) resKind
-- (2) type check type equation
; t_typats <- mappM tcHsKindedType k_typats
; t_rhs <- tcHsKindedType k_rhs
- -- construct type rewrite rule
-- !!!of the form: forall t_tvs. (tcdLName decl) t_typats = t_rhs
- ; return Nothing -- !!!TODO: need InstInfo for indexed types
+ ; return Nothing -- !!!TODO: need TyThing for indexed synonym
}}
-tcIdxTyInstDecl1 (decl@TyData {tcdND = new_or_data, tcdLName = L _ tc_name,
+tcIdxTyInstDecl1 (decl@TyData {tcdND = new_or_data, tcdLName = L loc tc_name,
tcdCons = cons})
- = kcIdxTyPats decl $ \k_tvs k_typats resKind ->
- do { -- (1) kind check the data declaration as usual
+ = kcIdxTyPats decl $ \k_tvs k_typats resKind family ->
+ do { -- check that the family declaration is for the right kind
+ unless (new_or_data == NewType && isNewTyCon family ||
+ new_or_data == DataType && isDataTyCon family) $
+ addErr (wrongKindOfFamily family)
+
+ ; -- (1) kind check the data declaration as usual
; k_decl <- kcDataDecl decl k_tvs
- ; let k_ctxt = tcdCtxt decl
- k_cons = tcdCons decl
+ ; let k_ctxt = tcdCtxt k_decl
+ k_cons = tcdCons k_decl
-- result kind must be '*' (otherwise, we have too few patterns)
; checkTc (isLiftedTypeKind resKind) $ tooFewParmsErr tc_name
; checkTc h98_syntax (badGadtIdxTyDecl tc_name)
-- Check that a newtype has exactly one constructor
- ; checkTc (new_or_data == DataType || isSingleton cons) $
- newtypeConError tc_name (length cons)
+ ; checkTc (new_or_data == DataType || isSingleton k_cons) $
+ newtypeConError tc_name (length k_cons)
; t_typats <- mappM tcHsKindedType k_typats
; stupid_theta <- tcHsKindedContext k_ctxt
+
+ ; rep_tc_name <- newFamInstTyConName tc_name (srcSpanStart loc)
; tycon <- fixM (\ tycon -> do
{ data_cons <- mappM (addLocM (tcConDecl unbox_strict new_or_data
- tycon t_tvs))
+ tycon t_tvs))
k_cons
; tc_rhs <-
case new_or_data of
DataType -> return (mkDataTyConRhs data_cons)
- NewType ->
- ASSERT( isSingleton data_cons )
- mkNewTyConRhs tc_name tycon (head data_cons)
- --vvvvvvv !!! need a new derived tc_name here
- ; buildAlgTyCon tc_name t_tvs stupid_theta tc_rhs Recursive
- False h98_syntax
+ NewType -> ASSERT( isSingleton data_cons )
+ mkNewTyConRhs tc_name tycon (head data_cons)
+ ; buildAlgTyCon rep_tc_name t_tvs stupid_theta tc_rhs Recursive
+ False h98_syntax (Just (family, t_typats))
-- We always assume that indexed types are recursive. Why?
-- (1) Due to their open nature, we can never be sure that a
-- further instance might not introduce a new recursive
})
-- construct result
- -- !!!twofold: (1) (ATyCon tycon) and (2) an equality axiom
- ; return Nothing -- !!!TODO: need InstInfo for indexed types
+ ; return $ Just (ATyCon tycon)
}}
where
h98_syntax = case cons of -- All constructors have same shape
-- check is only required for type functions.
--
kcIdxTyPats :: TyClDecl Name
- -> ([LHsTyVarBndr Name] -> [LHsType Name] -> Kind -> TcM a)
+ -> ([LHsTyVarBndr Name] -> [LHsType Name] -> Kind -> TyCon -> TcM a)
-- ^^kinded tvs ^^kinded ty pats ^^res kind
-> TcM a
kcIdxTyPats decl thing_inside
= kcHsTyVars (tcdTyVars decl) $ \tvs ->
- do { tc_ty_thing <- tcLookupLocated (tcdLName decl)
- ; let { tc_kind = case tc_ty_thing of
- AGlobal (ATyCon tycon) -> tyConKind tycon
- ; (kinds, resKind) = splitKindFunTys tc_kind
+ do { family <- tcLookupLocatedTyCon (tcdLName decl)
+ ; let { (kinds, resKind) = splitKindFunTys (tyConKind family)
; hs_typats = fromJust $ tcdTyPats decl }
-- we may not have more parameters than the kind indicates
-- type functions can have a higher-kinded result
; let resultKind = mkArrowKinds (drop (length hs_typats) kinds) resKind
- ; typats <- zipWithM kcCheckHsType hs_typats kinds
- ; thing_inside tvs typats resultKind
+ ; typats <- TcRnMonad.zipWithM kcCheckHsType hs_typats kinds
+ ; thing_inside tvs typats resultKind family
}
where
\end{code}
; cons' <- mappM (wrapLocM kc_con_decl) cons
; return (decl {tcdTyVars = tvs, tcdCtxt = ctxt', tcdCons = cons'}) }
where
- kc_con_decl (ConDecl name expl ex_tvs ex_ctxt details res) = do
+ -- doc comments are typechecked to Nothing here
+ kc_con_decl (ConDecl name expl ex_tvs ex_ctxt details res _) = do
kcHsTyVars ex_tvs $ \ex_tvs' -> do
ex_ctxt' <- kcHsContext ex_ctxt
details' <- kc_con_details details
res' <- case res of
ResTyH98 -> return ResTyH98
ResTyGADT ty -> do { ty' <- kcHsSigType ty; return (ResTyGADT ty') }
- return (ConDecl name expl ex_tvs' ex_ctxt' details' res')
+ return (ConDecl name expl ex_tvs' ex_ctxt' details' res' Nothing)
kc_con_details (PrefixCon btys)
= do { btys' <- mappM kc_larg_ty btys ; return (PrefixCon btys') }
kc_con_details (RecCon fields)
= do { fields' <- mappM kc_field fields; return (RecCon fields') }
- kc_field (fld, bty) = do { bty' <- kc_larg_ty bty ; return (fld, bty') }
+ kc_field (HsRecField fld bty d) = do { bty' <- kc_larg_ty bty ; return (HsRecField fld bty' d) }
kc_larg_ty bty = case new_or_data of
DataType -> kcHsSigType bty
; return (ATyCon (buildSynTyCon tc_name tvs' (SynonymTyCon rhs_ty'))) }
--------------------
-tcTyClDecl :: (Name -> RecFlag) -> TyClDecl Name -> TcM TyThing
+tcTyClDecl :: (Name -> RecFlag) -> TyClDecl Name -> TcM [TyThing]
tcTyClDecl calc_isrec decl
= tcAddDeclCtxt decl (tcTyClDecl1 calc_isrec decl)
tcTyClDecl1 _calc_isrec
(TyFunction {tcdLName = L _ tc_name, tcdTyVars = tvs, tcdKind = kind})
= tcTyVarBndrs tvs $ \ tvs' -> do
- { gla_exts <- doptM Opt_GlasgowExts
+ { traceTc (text "type family: " <+> ppr tc_name)
+ ; gla_exts <- doptM Opt_IndexedTypes
-- Check that we don't use kind signatures without Glasgow extensions
; checkTc gla_exts $ badSigTyDecl tc_name
- ; return (ATyCon (buildSynTyCon tc_name tvs' (OpenSynTyCon kind)))
+ ; return [ATyCon $ buildSynTyCon tc_name tvs' (OpenSynTyCon kind)]
}
-- kind signature for an indexed data type
tcTyClDecl1 _calc_isrec
(TyData {tcdND = new_or_data, tcdCtxt = ctxt, tcdTyVars = tvs,
- tcdLName = L _ tc_name, tcdKindSig = mb_ksig, tcdCons = []})
+ tcdLName = L _ tc_name, tcdKindSig = Just ksig, tcdCons = []})
= tcTyVarBndrs tvs $ \ tvs' -> do
- { extra_tvs <- tcDataKindSig mb_ksig
+ { traceTc (text "data/newtype family: " <+> ppr tc_name)
+ ; extra_tvs <- tcDataKindSig (Just ksig)
; let final_tvs = tvs' ++ extra_tvs -- we may not need these
; checkTc (null . unLoc $ ctxt) $ badKindSigCtxt tc_name
- ; gla_exts <- doptM Opt_GlasgowExts
+ ; gla_exts <- doptM Opt_IndexedTypes
-- Check that we don't use kind signatures without Glasgow extensions
; checkTc gla_exts $ badSigTyDecl tc_name
(case new_or_data of
DataType -> OpenDataTyCon
NewType -> OpenNewTyCon)
- Recursive False True
- ; return (ATyCon tycon)
+ Recursive False True Nothing
+ ; return [ATyCon tycon]
}
tcTyClDecl1 calc_isrec
ASSERT( isSingleton data_cons )
mkNewTyConRhs tc_name tycon (head data_cons)
; buildAlgTyCon tc_name final_tvs stupid_theta tc_rhs is_rec
- (want_generic && canDoGenerics data_cons) h98_syntax
+ (want_generic && canDoGenerics data_cons) h98_syntax Nothing
})
- ; return (ATyCon tycon)
+ ; return [ATyCon tycon]
}
where
is_rec = calc_isrec tc_name
= tcTyVarBndrs tvs $ \ tvs' -> do
{ ctxt' <- tcHsKindedContext ctxt
; fds' <- mappM (addLocM tc_fundep) fundeps
- ; ats' <- mappM (addLocM (tcTyClDecl1 (const Recursive))) ats
+ ; atss <- mappM (addLocM (tcTyClDecl1 (const Recursive))) ats
+ ; let ats' = zipWith setTyThingPoss atss (map (tcdTyVars . unLoc) ats)
; sig_stuff <- tcClassSigs class_name sigs meths
; clas <- fixM (\ clas ->
let -- This little knot is just so we can get
in
buildClass class_name tvs' ctxt' fds' ats'
sig_stuff tc_isrec)
- ; return (AClass clas) }
+ ; return (AClass clas : ats')
+ -- NB: Order is important due to the call to `mkGlobalThings' when
+ -- tying the the type and class declaration type checking knot.
+ }
where
tc_fundep (tvs1, tvs2) = do { tvs1' <- mappM tcLookupTyVar tvs1 ;
; tvs2' <- mappM tcLookupTyVar tvs2 ;
; return (tvs1', tvs2') }
+ -- For each AT argument compute the position of the corresponding class
+ -- parameter in the class head. This will later serve as a permutation
+ -- vector when checking the validity of instance declarations.
+ setTyThingPoss [ATyCon tycon] atTyVars =
+ let classTyVars = hsLTyVarNames tvs
+ poss = catMaybes
+ . map (`elemIndex` classTyVars)
+ . hsLTyVarNames
+ $ atTyVars
+ -- There will be no Nothing, as we already passed renaming
+ in
+ ATyCon (setTyConArgPoss tycon poss)
+ setTyThingPoss _ _ = panic "TcTyClsDecls.setTyThingPoss"
tcTyClDecl1 calc_isrec
(ForeignType {tcdLName = L _ tc_name, tcdExtName = tc_ext_name})
- = returnM (ATyCon (mkForeignTyCon tc_name tc_ext_name liftedTypeKind 0))
+ = returnM [ATyCon (mkForeignTyCon tc_name tc_ext_name liftedTypeKind 0)]
-----------------------------------
tcConDecl :: Bool -- True <=> -funbox-strict_fields
- -> NewOrData -> TyCon -> [TyVar]
- -> ConDecl Name -> TcM DataCon
+ -> NewOrData
+ -> TyCon -> [TyVar]
+ -> ConDecl Name
+ -> TcM DataCon
tcConDecl unbox_strict NewType tycon tc_tvs -- Newtypes
- (ConDecl name _ ex_tvs ex_ctxt details ResTyH98)
+ (ConDecl name _ ex_tvs ex_ctxt details ResTyH98 _)
= do { let tc_datacon field_lbls arg_ty
= do { arg_ty' <- tcHsKindedType arg_ty -- No bang on newtype
; buildDataCon (unLoc name) False {- Prefix -}
; checkTc (null ex_tvs && null (unLoc ex_ctxt)) (newtypeExError name)
; case details of
- PrefixCon [arg_ty] -> tc_datacon [] arg_ty
- RecCon [(field_lbl, arg_ty)] -> tc_datacon [field_lbl] arg_ty
- other -> failWithTc (newtypeFieldErr name (length (hsConArgs details)))
+ PrefixCon [arg_ty] -> tc_datacon [] arg_ty
+ RecCon [HsRecField field_lbl arg_ty _] -> tc_datacon [field_lbl] arg_ty
+ other ->
+ failWithTc (newtypeFieldErr name (length (hsConArgs details)))
-- Check that the constructor has exactly one field
}
tcConDecl unbox_strict DataType tycon tc_tvs -- Data types
- (ConDecl name _ tvs ctxt details res_ty)
+ (ConDecl name _ tvs ctxt details res_ty _)
= tcTyVarBndrs tvs $ \ tvs' -> do
{ ctxt' <- tcHsKindedContext ctxt
; (univ_tvs, ex_tvs, eq_preds, data_tc) <- tcResultType tycon tc_tvs tvs' res_ty
; let
+ -- Tiresome: tidy the tyvar binders, since tc_tvs and tvs' may have the same OccNames
tc_datacon is_infix field_lbls btys
= do { let bangs = map getBangStrictness btys
; arg_tys <- mappM tcHsBangType btys
; buildDataCon (unLoc name) is_infix
- (argStrictness unbox_strict tycon bangs arg_tys)
+ (argStrictness unbox_strict bangs arg_tys)
(map unLoc field_lbls)
univ_tvs ex_tvs eq_preds ctxt' arg_tys
data_tc }
- -- NB: we put data_tc, the type constructor gotten from the constructor
- -- type signature into the data constructor; that way
- -- checkValidDataCon can complain if it's wrong.
+ -- NB: we put data_tc, the type constructor gotten from the
+ -- constructor type signature into the data constructor;
+ -- that way checkValidDataCon can complain if it's wrong.
; case details of
PrefixCon btys -> tc_datacon False [] btys
InfixCon bty1 bty2 -> tc_datacon True [] [bty1,bty2]
RecCon fields -> tc_datacon False field_names btys
where
- (field_names, btys) = unzip fields
+ (field_names, btys) = unzip [ (n, t) | HsRecField n t _ <- fields ]
}
-> [TyVar] -- where MkT :: forall a b c. ...
-> ResType Name
-> TcM ([TyVar], -- Universal
- [TyVar], -- Existential
+ [TyVar], -- Existential (distinct OccNames from univs)
[(TyVar,Type)], -- Equality predicates
TyCon) -- TyCon given in the ResTy
-- We don't check that the TyCon given in the ResTy is
-- ([a,z,c], [x,y], [a:=:(x,y), c:=:z], T)
= do { (dc_tycon, res_tys) <- tcLHsConResTy res_ty
- -- NB: tc_tvs and dc_tvs are distinct
- ; let univ_tvs = choose_univs [] tc_tvs res_tys
+
+ ; let univ_tvs = choose_univs [] tidy_tc_tvs res_tys
-- Each univ_tv is either a dc_tv or a tc_tv
ex_tvs = dc_tvs `minusList` univ_tvs
eq_spec = [ (tv, ty) | (tv,ty) <- univ_tvs `zip` res_tys,
| otherwise
= tc_tv : choose_univs used tc_tvs res_tys
--------------------
+ -- NB: tc_tvs and dc_tvs are distinct, but
+ -- we want them to be *visibly* distinct, both for
+ -- interface files and general confusion. So rename
+ -- the tc_tvs, since they are not used yet (no
+ -- consequential renaming needed)
+ init_occ_env = initTidyOccEnv (map getOccName dc_tvs)
+ (_, tidy_tc_tvs) = mapAccumL tidy_one init_occ_env tc_tvs
+ tidy_one env tv = (env', setTyVarName tv (tidyNameOcc name occ'))
+ where
+ name = tyVarName tv
+ (env', occ') = tidyOccName env (getOccName name)
+
+ -------------------
argStrictness :: Bool -- True <=> -funbox-strict_fields
- -> TyCon -> [HsBang]
+ -> [HsBang]
-> [TcType] -> [StrictnessMark]
-argStrictness unbox_strict tycon bangs arg_tys
+argStrictness unbox_strict bangs arg_tys
= ASSERT( length bangs == length arg_tys )
- zipWith (chooseBoxingStrategy unbox_strict tycon) arg_tys bangs
+ zipWith (chooseBoxingStrategy unbox_strict) arg_tys bangs
-- We attempt to unbox/unpack a strict field when either:
-- (i) The field is marked '!!', or
--
-- We have turned off unboxing of newtypes because coercions make unboxing
-- and reboxing more complicated
-chooseBoxingStrategy :: Bool -> TyCon -> TcType -> HsBang -> StrictnessMark
-chooseBoxingStrategy unbox_strict_fields tycon arg_ty bang
+chooseBoxingStrategy :: Bool -> TcType -> HsBang -> StrictnessMark
+chooseBoxingStrategy unbox_strict_fields arg_ty bang
= case bang of
HsNoBang -> NotMarkedStrict
HsStrict | unbox_strict_fields
can_unbox arg_ty = case splitTyConApp_maybe arg_ty of
Nothing -> False
Just (arg_tycon, tycon_args) ->
- not (isRecursiveTyCon tycon) &&
+ not (isRecursiveTyCon arg_tycon) && -- Note [Recusive unboxing]
isProductTyCon arg_tycon &&
(if isNewTyCon arg_tycon then
can_unbox (newTyConInstRhs arg_tycon tycon_args)
else True)
\end{code}
+Note [Recursive unboxing]
+~~~~~~~~~~~~~~~~~~~~~~~~~
+Be careful not to try to unbox this!
+ data T = MkT !T Int
+But it's the *argument* type that matters. This is fine:
+ data S = MkS S !Int
+because Int is non-recursive.
+
%************************************************************************
%* *
\subsection{Dependency analysis}
= ptext SLIT("Indexed type instance has too few parameters:") <+>
quotes (ppr tc_name)
-badBootTyIdxDeclErr = ptext SLIT("Illegal indexed type instance in hs-boot file")
+badBootTyIdxDeclErr =
+ ptext SLIT("Illegal indexed type instance in hs-boot file")
+
+wrongKindOfFamily family =
+ ptext SLIT("Wrong category of type instance; declaration was for a") <+>
+ kindOfFamily
+ where
+ kindOfFamily | isSynTyCon family = ptext SLIT("type synonym")
+ | isDataTyCon family = ptext SLIT("data type")
+ | isNewTyCon family = ptext SLIT("newtype")
emptyConDeclsErr tycon
= sep [quotes (ppr tycon) <+> ptext SLIT("has no constructors"),
projects / ghc-hetmet.git / blobdiff