%
-% (c) The AQUA Project, Glasgow University, 1996
+% (c) The AQUA Project, Glasgow University, 1996-1998
%
\section[TcTyClsDecls]{Typecheck type and class declarations}
\begin{code}
-#include "HsVersions.h"
-
module TcTyClsDecls (
- tcTyAndClassDecls1
+ tcTyAndClassDecls
) where
-IMP_Ubiq(){-uitous-}
+#include "HsVersions.h"
-import HsSyn ( HsDecl(..), TyDecl(..), ConDecl(..), ConDetails(..), BangType(..),
- ClassDecl(..), HsType(..), HsTyVar, DefaultDecl, InstDecl,
- IfaceSig, Sig(..), MonoBinds, Fake, InPat, HsBinds(..), HsExpr, NewOrData,
- hsDeclName
- )
-import RnHsSyn ( RenamedTyDecl(..), RenamedClassDecl(..), SYN_IE(RenamedHsDecl)
+import HsSyn ( TyClDecl(..), HsConDetails(..), HsTyVarBndr(..),
+ ConDecl(..), Sig(..), , NewOrData(..),
+ tyClDeclTyVars, isSynDecl, LConDecl,
+ LTyClDecl, tcdName, LHsTyVarBndr, LHsContext
)
-import TcHsSyn ( SYN_IE(TcHsBinds), TcIdOcc(..) )
-
-import TcMonad
-import Inst ( SYN_IE(InstanceMapper) )
-import TcClassDcl ( tcClassDecl1 )
-import TcEnv ( tcExtendTyConEnv, tcExtendClassEnv )
-import SpecEnv ( SpecEnv )
-import TcKind ( TcKind, newKindVars )
-import TcTyDecls ( tcTyDecl, mkDataBinds )
-import TcMonoType ( tcTyVarScope )
-
-import Bag
-import Class ( SYN_IE(Class) )
-import Digraph ( stronglyConnComp, SCC(..) )
-import Name ( Name, getSrcLoc, isTvOcc, nameOccName )
+import HsTypes ( HsBang(..), getBangStrictness )
+import BasicTypes ( RecFlag(..), StrictnessMark(..) )
+import HscTypes ( implicitTyThings )
+import BuildTyCl ( buildClass, buildAlgTyCon, buildSynTyCon, buildDataCon,
+ mkDataTyConRhs, mkNewTyConRhs )
+import TcRnMonad
+import TcEnv ( TcTyThing(..), TyThing(..),
+ tcLookupLocated, tcLookupLocatedGlobal,
+ tcExtendGlobalEnv, tcExtendKindEnv,
+ tcExtendRecEnv, tcLookupTyVar )
+import TcTyDecls ( calcTyConArgVrcs, calcRecFlags, calcClassCycles, calcSynCycles )
+import TcClassDcl ( tcClassSigs, tcAddDeclCtxt )
+import TcHsType ( kcHsTyVars, kcHsLiftedSigType, kcHsType,
+ kcHsContext, tcTyVarBndrs, tcHsKindedType, tcHsKindedContext,
+ kcHsSigType, tcHsBangType, tcLHsConSig )
+import TcMType ( newKindVar, checkValidTheta, checkValidType, checkFreeness,
+ UserTypeCtxt(..), SourceTyCtxt(..) )
+import TcUnify ( unifyKind )
+import TcType ( TcKind, ThetaType, TcType, tyVarsOfType,
+ mkArrowKind, liftedTypeKind, mkTyVarTys, tcEqTypes,
+ tcSplitSigmaTy, tcEqType )
+import Type ( splitTyConApp_maybe, pprThetaArrow, pprParendType )
+import Generics ( validGenericMethodType, canDoGenerics )
+import Class ( Class, className, classTyCon, DefMeth(..), classBigSig, classTyVars )
+import TyCon ( TyCon, ArgVrcs,
+ tyConDataCons, mkForeignTyCon, isProductTyCon, isRecursiveTyCon,
+ tyConStupidTheta, getSynTyConDefn, tyConDataCons, isSynTyCon, tyConName )
+import DataCon ( DataCon, dataConWrapId, dataConName, dataConSig,
+ dataConFieldLabels, dataConOrigArgTys, dataConTyCon )
+import Type ( zipTopTvSubst, substTys )
+import Var ( TyVar, idType, idName )
+import VarSet ( elemVarSet )
+import Name ( Name )
import Outputable
-import Pretty
-import Maybes ( mapMaybe )
-import UniqSet ( SYN_IE(UniqSet), emptyUniqSet,
- unitUniqSet, unionUniqSets,
- unionManyUniqSets, uniqSetToList )
-import SrcLoc ( SrcLoc )
-import TyCon ( TyCon, SYN_IE(Arity) )
-import Unique ( Unique, Uniquable(..) )
-import Util ( panic{-, pprTrace-} )
-
+import Util ( zipLazy, isSingleton, notNull, sortLe )
+import List ( partition )
+import SrcLoc ( Located(..), unLoc, getLoc )
+import ListSetOps ( equivClasses )
+import Digraph ( SCC(..) )
+import CmdLineOpts ( DynFlag( Opt_GlasgowExts, Opt_Generics, Opt_UnboxStrictFields ) )
\end{code}
-The main function
-~~~~~~~~~~~~~~~~~
-\begin{code}
-tcTyAndClassDecls1 :: TcEnv s -> InstanceMapper -- Knot tying stuff
- -> [RenamedHsDecl]
- -> TcM s (TcEnv s)
-tcTyAndClassDecls1 unf_env inst_mapper decls
- = sortByDependency decls `thenTc` \ groups ->
- tcGroups unf_env inst_mapper groups
+%************************************************************************
+%* *
+\subsection{Type checking for type and class declarations}
+%* *
+%************************************************************************
-tcGroups unf_env inst_mapper []
- = tcGetEnv `thenNF_Tc` \ env ->
- returnTc env
+Dealing with a group
+~~~~~~~~~~~~~~~~~~~~
+Consider a mutually-recursive group, binding
+a type constructor T and a class C.
-tcGroups unf_env inst_mapper (group:groups)
- = tcGroup unf_env inst_mapper group `thenTc` \ new_env ->
+Step 1: getInitialKind
+ Construct a KindEnv by binding T and C to a kind variable
- -- Extend the environment using the new tycons and classes
- tcSetEnv new_env $
+Step 2: kcTyClDecl
+ In that environment, do a kind check
- -- Do the remaining groups
- tcGroups unf_env inst_mapper groups
-\end{code}
+Step 3: Zonk the kinds
-Dealing with a group
-~~~~~~~~~~~~~~~~~~~~
-\begin{code}
-tcGroup :: TcEnv s -> InstanceMapper -> Bag RenamedHsDecl -> TcM s (TcEnv s)
-tcGroup unf_env inst_mapper decls
- = -- TIE THE KNOT
- fixTc ( \ ~(tycons,classes,_) ->
-
- -- EXTEND TYPE AND CLASS ENVIRONMENTS
- -- NB: it's important that the tycons and classes come back in just
- -- the same order from this fix as from get_binders, so that these
- -- extend-env things work properly. A bit UGH-ish.
- tcExtendTyConEnv tycon_names_w_arities tycons $
- tcExtendClassEnv class_names classes $
-
- -- DEAL WITH TYPE VARIABLES
- tcTyVarScope tyvar_names ( \ tyvars ->
-
- -- DEAL WITH THE DEFINITIONS THEMSELVES
- foldBag combine (tcDecl unf_env inst_mapper)
- (returnTc (emptyBag, emptyBag))
- decls
- ) `thenTc` \ (tycon_bag,class_bag) ->
- let
- tycons = bagToList tycon_bag
- classes = bagToList class_bag
- in
-
- -- SNAFFLE ENV TO RETURN
- tcGetEnv `thenNF_Tc` \ final_env ->
-
- returnTc (tycons, classes, final_env)
- ) `thenTc` \ (_, _, final_env) ->
-
- returnTc final_env
+Step 4: buildTyConOrClass
+ Construct an environment binding T to a TyCon and C to a Class.
+ a) Their kinds comes from zonking the relevant kind variable
+ b) Their arity (for synonyms) comes direct from the decl
+ c) The funcional dependencies come from the decl
+ d) The rest comes a knot-tied binding of T and C, returned from Step 4
+ e) The variances of the tycons in the group is calculated from
+ the knot-tied stuff
- where
- (tyvar_names, tycon_names_w_arities, class_names) = get_binders decls
+Step 5: tcTyClDecl1
+ In this environment, walk over the decls, constructing the TyCons and Classes.
+ This uses in a strict way items (a)-(c) above, which is why they must
+ be constructed in Step 4. Feed the results back to Step 4.
+ For this step, pass the is-recursive flag as the wimp-out flag
+ to tcTyClDecl1.
+
- combine do_a do_b
- = do_a `thenTc` \ (a1,a2) ->
- do_b `thenTc` \ (b1,b2) ->
- returnTc (a1 `unionBags` b1, a2 `unionBags` b2)
-\end{code}
+Step 6: Extend environment
+ We extend the type environment with bindings not only for the TyCons and Classes,
+ but also for their "implicit Ids" like data constructors and class selectors
-Dealing with one decl
-~~~~~~~~~~~~~~~~~~~~~
-\begin{code}
-tcDecl :: TcEnv s -> InstanceMapper
- -> RenamedHsDecl
- -> TcM s (Bag TyCon, Bag Class)
+Step 7: checkValidTyCl
+ For a recursive group only, check all the decls again, just
+ to check all the side conditions on validity. We could not
+ do this before because we were in a mutually recursive knot.
-tcDecl unf_env inst_mapper (TyD decl)
- = tcTyDecl decl `thenTc` \ tycon ->
- returnTc (unitBag tycon, emptyBag)
-tcDecl unf_env inst_mapper (ClD decl)
- = tcClassDecl1 unf_env inst_mapper decl `thenTc` \ clas ->
- returnTc (emptyBag, unitBag clas)
-\end{code}
+The knot-tying parameters: @rec_details_list@ is an alist mapping @Name@s to
+@TyThing@s. @rec_vrcs@ is a finite map from @Name@s to @ArgVrcs@s.
-Dependency analysis
-~~~~~~~~~~~~~~~~~~~
\begin{code}
-sortByDependency :: [RenamedHsDecl] -> TcM s [Bag RenamedHsDecl]
-sortByDependency decls
- = let -- CHECK FOR SYNONYM CYCLES
- syn_sccs = stronglyConnComp (filter is_syn_decl edges)
- syn_cycles = [ decls | CyclicSCC decls <- syn_sccs]
-
- in
- checkTc (null syn_cycles) (typeCycleErr syn_cycles) `thenTc_`
+tcTyAndClassDecls :: [Name] -> [LTyClDecl Name]
+ -> TcM TcGblEnv -- Input env extended by types and classes
+ -- and their implicit Ids,DataCons
+tcTyAndClassDecls boot_names decls
+ = do { -- First check for cyclic type synonysm or classes
+ -- See notes with checkCycleErrs
+ checkCycleErrs decls
+ ; mod <- getModule
+ ; traceTc (text "tcTyAndCl" <+> ppr mod <+> ppr boot_names)
+ ; (syn_tycons, alg_tyclss) <- fixM (\ ~(rec_syn_tycons, rec_alg_tyclss) ->
+ do { let { -- Calculate variances and rec-flag
+ ; (syn_decls, alg_decls) = partition (isSynDecl . unLoc) 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 }
+ ; tcExtendRecEnv gbl_things $ do
+
+ -- Kind-check the declarations
+ { (kc_syn_decls, kc_alg_decls) <- kcTyClDecls syn_decls alg_decls
+
+ ; let { calc_vrcs = calcTyConArgVrcs (rec_syn_tycons ++ rec_alg_tyclss)
+ ; calc_rec = calcRecFlags boot_names rec_alg_tyclss
+ ; tc_decl = addLocM (tcTyClDecl calc_vrcs calc_rec) }
+ -- Type-check the type synonyms, and extend the envt
+ ; syn_tycons <- tcSynDecls calc_vrcs 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)
+ }}})
+ -- Finished with knot-tying now
+ -- Extend the environment with the finished things
+ ; tcExtendGlobalEnv (syn_tycons ++ alg_tyclss) $ do
+
+ -- Perform the validity check
+ { traceTc (text "ready for validity check")
+ ; mappM_ (addLocM checkValidTyCl) decls
+ ; traceTc (text "done")
+
+ -- Add the implicit things;
+ -- we want them in the environment because
+ -- they may be mentioned in interface files
+ ; let { implicit_things = concatMap implicitTyThings alg_tyclss }
+ ; traceTc ((text "Adding" <+> ppr alg_tyclss) $$ (text "and" <+> ppr implicit_things))
+ ; tcExtendGlobalEnv implicit_things getGblEnv
+ }}
+
+mkGlobalThings :: [LTyClDecl Name] -- The decls
+ -> [TyThing] -- Knot-tied, in 1-1 correspondence with the decls
+ -> [(Name,TyThing)]
+-- Driven by the Decls, and treating the TyThings lazily
+-- make a TypeEnv for the new things
+mkGlobalThings decls things
+ = map mk_thing (decls `zipLazy` things)
+ where
+ mk_thing (L _ (ClassDecl {tcdLName = L _ name}), ~(AClass cl))
+ = (name, AClass cl)
+ mk_thing (L _ decl, ~(ATyCon tc))
+ = (tcdName decl, ATyCon tc)
+\end{code}
- let -- CHECK FOR CLASS CYCLES
- cls_sccs = stronglyConnComp (filter is_cls_decl edges)
- cls_cycles = [ decls | CyclicSCC decls <- cls_sccs]
- in
- checkTc (null cls_cycles) (classCycleErr cls_cycles) `thenTc_`
+%************************************************************************
+%* *
+ Kind checking
+%* *
+%************************************************************************
- -- DO THE MAIN DEPENDENCY ANALYSIS
- let
- decl_sccs = stronglyConnComp (filter is_ty_cls_decl edges)
- scc_bags = map bag_acyclic decl_sccs
- in
- returnTc (scc_bags)
+We need to kind check all types in the mutually recursive group
+before we know the kind of the type variables. For example:
- where
- edges = mapMaybe mk_edges decls
-
-bag_acyclic (AcyclicSCC scc) = unitBag scc
-bag_acyclic (CyclicSCC sccs) = listToBag sccs
+class C a where
+ op :: D b => a -> b -> b
-is_syn_decl (TyD (TySynonym _ _ _ _), _, _) = True
-is_syn_decl _ = False
+class D c where
+ bop :: (Monad c) => ...
-is_ty_cls_decl (TyD _, _, _) = True
-is_ty_cls_decl (ClD _, _, _) = True
-is_ty_cls_decl other = False
+Here, the kind of the locally-polymorphic type variable "b"
+depends on *all the uses of class D*. For example, the use of
+Monad c in bop's type signature means that D must have kind Type->Type.
-is_cls_decl (ClD _, _, _) = True
-is_cls_decl other = False
-\end{code}
+However type synonyms work differently. They can have kinds which don't
+just involve (->) and *:
+ type R = Int# -- Kind #
+ type S a = Array# a -- Kind * -> #
+ type T a b = (# a,b #) -- Kind * -> * -> (# a,b #)
+So we must infer their kinds from their right-hand sides *first* and then
+use them, whereas for the mutually recursive data types D we bring into
+scope kind bindings D -> k, where k is a kind variable, and do inference.
-Edges in Type/Class decls
-~~~~~~~~~~~~~~~~~~~~~~~~~
\begin{code}
-mk_edges decl@(TyD (TyData _ ctxt name _ condecls derivs _ _))
- = Just (decl, uniqueOf name, uniqSetToList (get_ctxt ctxt `unionUniqSets`
- get_cons condecls `unionUniqSets`
- get_deriv derivs))
+kcTyClDecls syn_decls alg_decls
+ = do { -- First extend the kind env with each data
+ -- type and class, mapping them to a type variable
+ alg_kinds <- mappM getInitialKind alg_decls
+ ; tcExtendKindEnv alg_kinds $ do
+
+ -- Now kind-check the type synonyms, in dependency order
+ -- We do these differently to data type and classes,
+ -- because a type synonym can be an unboxed type
+ -- type Foo = Int#
+ -- and a kind variable can't unify with UnboxedTypeKind
+ -- So we infer their kinds in dependency order
+ { (kc_syn_decls, syn_kinds) <- kcSynDecls (calcSynCycles syn_decls)
+ ; tcExtendKindEnv syn_kinds $ do
+
+ -- Now kind-check the data type and class declarations,
+ -- returning kind-annotated decls
+ { kc_alg_decls <- mappM (wrapLocM kcTyClDecl) alg_decls
+
+ ; return (kc_syn_decls, kc_alg_decls) }}}
+
+------------------------------------------------------------------------
+getInitialKind :: LTyClDecl Name -> TcM (Name, TcKind)
+
+getInitialKind decl
+ = newKindVar `thenM` \ kind ->
+ returnM (unLoc (tcdLName (unLoc decl)), kind)
+
+----------------
+kcSynDecls :: [SCC (LTyClDecl Name)]
+ -> TcM ([LTyClDecl Name], -- Kind-annotated decls
+ [(Name,TcKind)]) -- Kind bindings
+kcSynDecls []
+ = return ([], [])
+kcSynDecls (group : groups)
+ = do { (decl, nk) <- kcSynDecl group
+ ; (decls, nks) <- tcExtendKindEnv [nk] (kcSynDecls groups)
+ ; return (decl:decls, nk:nks) }
+
+----------------
+kcSynDecl :: SCC (LTyClDecl Name)
+ -> TcM (LTyClDecl Name, -- Kind-annotated decls
+ (Name,TcKind)) -- Kind bindings
+kcSynDecl (AcyclicSCC ldecl@(L loc decl))
+ = tcAddDeclCtxt decl $
+ kcHsTyVars (tcdTyVars decl) (\ k_tvs ->
+ do { traceTc (text "kcd1" <+> ppr (unLoc (tcdLName decl)) <+> brackets (ppr (tcdTyVars decl))
+ <+> brackets (ppr k_tvs))
+ ; (k_rhs, rhs_kind) <- kcHsType (tcdSynRhs decl)
+ ; traceTc (text "kcd2" <+> ppr (unLoc (tcdLName decl)))
+ ; let tc_kind = foldr (mkArrowKind . kindedTyVarKind) rhs_kind k_tvs
+ ; return (L loc (decl { tcdTyVars = k_tvs, tcdSynRhs = k_rhs }),
+ (unLoc (tcdLName decl), tc_kind)) })
+
+kcSynDecl (CyclicSCC decls)
+ = do { recSynErr decls; failM } -- Fail here to avoid error cascade
+ -- of out-of-scope tycons
+
+------------------------------------------------------------------------
+kcTyClDecl :: TyClDecl Name -> TcM (TyClDecl Name)
+ -- Not used for type synonyms (see kcSynDecl)
+
+kcTyClDecl decl@(TyData {tcdND = new_or_data, tcdCtxt = ctxt, tcdCons = cons})
+ = kcTyClDeclBody decl $ \ tvs' ->
+ do { ctxt' <- kcHsContext ctxt
+ ; cons' <- mappM (wrapLocM kc_con_decl) cons
+ ; return (decl {tcdTyVars = tvs', tcdCtxt = ctxt', tcdCons = cons'}) }
+ where
+ kc_con_decl (ConDecl name ex_tvs ex_ctxt details)
+ = kcHsTyVars ex_tvs $ \ ex_tvs' ->
+ do { ex_ctxt' <- kcHsContext ex_ctxt
+ ; details' <- kc_con_details details
+ ; return (ConDecl name ex_tvs' ex_ctxt' details')}
+ kc_con_decl (GadtDecl name ty)
+ = do { ty' <- kcHsSigType ty
+ ; return (GadtDecl name ty') }
+
+ kc_con_details (PrefixCon btys)
+ = do { btys' <- mappM kc_larg_ty btys ; return (PrefixCon btys') }
+ kc_con_details (InfixCon bty1 bty2)
+ = do { bty1' <- kc_larg_ty bty1; bty2' <- kc_larg_ty bty2; return (InfixCon bty1' bty2') }
+ 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_larg_ty bty = case new_or_data of
+ DataType -> kcHsSigType bty
+ NewType -> kcHsLiftedSigType bty
+ -- Can't allow an unlifted type for newtypes, because we're effectively
+ -- going to remove the constructor while coercing it to a lifted type.
+ -- And newtypes can't be bang'd
+
+kcTyClDecl decl@(ClassDecl {tcdCtxt = ctxt, tcdSigs = sigs})
+ = kcTyClDeclBody decl $ \ tvs' ->
+ do { ctxt' <- kcHsContext ctxt
+ ; sigs' <- mappM (wrapLocM kc_sig) sigs
+ ; return (decl {tcdTyVars = tvs', tcdCtxt = ctxt', tcdSigs = sigs'}) }
+ where
+ kc_sig (Sig nm op_ty) = do { op_ty' <- kcHsLiftedSigType op_ty
+ ; return (Sig nm op_ty') }
+ kc_sig other_sig = return other_sig
+
+kcTyClDecl decl@(ForeignType {})
+ = return decl
+
+kcTyClDeclBody :: TyClDecl Name
+ -> ([LHsTyVarBndr Name] -> TcM a)
+ -> TcM a
+ -- Extend the env with bindings for the tyvars, taken from
+ -- the kind of the tycon/class. Give it to the thing inside, and
+ -- check the result kind matches
+kcTyClDeclBody decl thing_inside
+ = tcAddDeclCtxt decl $
+ kcHsTyVars (tyClDeclTyVars decl) $ \ kinded_tvs ->
+ do { tc_ty_thing <- tcLookupLocated (tcdLName decl)
+ ; let tc_kind = case tc_ty_thing of { AThing k -> k }
+ ; unifyKind tc_kind (foldr (mkArrowKind . kindedTyVarKind)
+ (result_kind decl)
+ kinded_tvs)
+ ; thing_inside kinded_tvs }
+ where
+ result_kind (TyData { tcdKindSig = Just kind }) = kind
+ result_kind other = liftedTypeKind
+ -- On GADT-style declarations we allow a kind signature
+ -- data T :: *->* where { ... }
-mk_edges decl@(TyD (TySynonym name _ rhs _))
- = Just (decl, uniqueOf name, uniqSetToList (get_ty rhs))
+kindedTyVarKind (L _ (KindedTyVar _ k)) = k
+\end{code}
-mk_edges decl@(ClD (ClassDecl ctxt name _ sigs _ _ _))
- = Just (decl, uniqueOf name, uniqSetToList (get_ctxt ctxt `unionUniqSets`
- get_sigs sigs))
-mk_edges other_decl = Nothing
+%************************************************************************
+%* *
+\subsection{Type checking}
+%* *
+%************************************************************************
-get_ctxt ctxt = unionManyUniqSets (map (set_name.fst) ctxt)
+\begin{code}
+tcSynDecls :: (Name -> ArgVrcs) -> [LTyClDecl Name] -> TcM [TyThing]
+tcSynDecls calc_vrcs [] = return []
+tcSynDecls calc_vrcs (decl : decls)
+ = do { syn_tc <- addLocM (tcSynDecl calc_vrcs) decl
+ ; syn_tcs <- tcExtendGlobalEnv [syn_tc] (tcSynDecls calc_vrcs decls)
+ ; return (syn_tc : syn_tcs) }
+
+tcSynDecl calc_vrcs
+ (TySynonym {tcdLName = L _ tc_name, tcdTyVars = tvs, tcdSynRhs = rhs_ty})
+ = tcTyVarBndrs tvs $ \ tvs' -> do
+ { traceTc (text "tcd1" <+> ppr tc_name)
+ ; rhs_ty' <- tcHsKindedType rhs_ty
+ ; return (ATyCon (buildSynTyCon tc_name tvs' rhs_ty' (calc_vrcs tc_name))) }
+
+--------------------
+tcTyClDecl :: (Name -> ArgVrcs) -> (Name -> RecFlag)
+ -> TyClDecl Name -> TcM TyThing
+
+tcTyClDecl calc_vrcs calc_isrec decl
+ = tcAddDeclCtxt decl (tcTyClDecl1 calc_vrcs calc_isrec decl)
+
+tcTyClDecl1 calc_vrcs calc_isrec
+ (TyData {tcdND = new_or_data, tcdCtxt = ctxt, tcdTyVars = tvs,
+ tcdLName = L _ tc_name, tcdCons = cons})
+ = tcTyVarBndrs tvs $ \ tvs' -> do
+ { stupid_theta <- tcStupidTheta ctxt cons
+ ; want_generic <- doptM Opt_Generics
+ ; tycon <- fixM (\ tycon -> do
+ { unbox_strict <- doptM Opt_UnboxStrictFields
+ ; gla_exts <- doptM Opt_GlasgowExts
+ ; checkTc (gla_exts || h98_syntax) (badGadtDecl tc_name)
+
+ ; data_cons <- mappM (addLocM (tcConDecl unbox_strict new_or_data tycon tvs')) cons
+ ; let tc_rhs = case new_or_data of
+ DataType -> mkDataTyConRhs stupid_theta data_cons
+ NewType -> ASSERT( isSingleton data_cons )
+ mkNewTyConRhs tycon (head data_cons)
+ ; buildAlgTyCon tc_name tvs' tc_rhs arg_vrcs is_rec
+ (want_generic && canDoGenerics data_cons)
+ })
+ ; return (ATyCon tycon)
+ }
+ where
+ arg_vrcs = calc_vrcs tc_name
+ is_rec = calc_isrec tc_name
+ h98_syntax = case cons of -- All constructors have same shape
+ L _ (GadtDecl {}) : _ -> False
+ other -> True
+
+tcTyClDecl1 calc_vrcs calc_isrec
+ (ClassDecl {tcdLName = L _ class_name, tcdTyVars = tvs,
+ tcdCtxt = ctxt, tcdMeths = meths,
+ tcdFDs = fundeps, tcdSigs = sigs} )
+ = tcTyVarBndrs tvs $ \ tvs' -> do
+ { ctxt' <- tcHsKindedContext ctxt
+ ; fds' <- mappM (addLocM tc_fundep) fundeps
+ ; sig_stuff <- tcClassSigs class_name sigs meths
+ ; clas <- fixM (\ clas ->
+ let -- This little knot is just so we can get
+ -- hold of the name of the class TyCon, which we
+ -- need to look up its recursiveness and variance
+ tycon_name = tyConName (classTyCon clas)
+ tc_isrec = calc_isrec tycon_name
+ tc_vrcs = calc_vrcs tycon_name
+ in
+ buildClass class_name tvs' ctxt' fds'
+ sig_stuff tc_isrec tc_vrcs)
+ ; return (AClass clas) }
+ where
+ tc_fundep (tvs1, tvs2) = do { tvs1' <- mappM tcLookupTyVar tvs1 ;
+ ; tvs2' <- mappM tcLookupTyVar tvs2 ;
+ ; return (tvs1', tvs2') }
+
+
+tcTyClDecl1 calc_vrcs calc_isrec
+ (ForeignType {tcdLName = L _ tc_name, tcdExtName = tc_ext_name})
+ = returnM (ATyCon (mkForeignTyCon tc_name tc_ext_name liftedTypeKind 0 []))
+
+-----------------------------------
+tcConDecl :: Bool -- True <=> -funbox-strict_fields
+ -> NewOrData -> TyCon -> [TyVar]
+ -> ConDecl Name -> TcM DataCon
+
+tcConDecl unbox_strict NewType tycon tc_tvs -- Newtypes
+ (ConDecl name ex_tvs ex_ctxt details)
+ = ASSERT( null ex_tvs && null (unLoc ex_ctxt) )
+ do { let tc_datacon field_lbls arg_ty
+ = do { arg_ty' <- tcHsKindedType arg_ty -- No bang on newtype
+ ; buildDataCon (unLoc name) False {- Prefix -}
+ True {- Vanilla -} [NotMarkedStrict]
+ (map unLoc field_lbls)
+ tc_tvs [] [arg_ty']
+ tycon (mkTyVarTys tc_tvs) }
+ ; case details of
+ PrefixCon [arg_ty] -> tc_datacon [] arg_ty
+ RecCon [(field_lbl, arg_ty)] -> tc_datacon [field_lbl] arg_ty }
+
+tcConDecl unbox_strict DataType tycon tc_tvs -- Ordinary data types
+ (ConDecl name ex_tvs ex_ctxt details)
+ = tcTyVarBndrs ex_tvs $ \ ex_tvs' -> do
+ { ex_ctxt' <- tcHsKindedContext ex_ctxt
+ ; let
+ is_vanilla = null ex_tvs && null (unLoc ex_ctxt)
+ -- Vanilla iff no ex_tvs and no context
+
+ tc_datacon is_infix field_lbls btys
+ = do { let { bangs = map getBangStrictness btys }
+ ; arg_tys <- mappM tcHsBangType btys
+ ; buildDataCon (unLoc name) is_infix is_vanilla
+ (argStrictness unbox_strict tycon bangs arg_tys)
+ (map unLoc field_lbls)
+ (tc_tvs ++ ex_tvs')
+ ex_ctxt'
+ arg_tys
+ tycon (mkTyVarTys tc_tvs) }
+ ; case details of
+ PrefixCon btys -> tc_datacon False [] btys
+ InfixCon bty1 bty2 -> tc_datacon True [] [bty1,bty2]
+ RecCon fields -> do { checkTc is_vanilla (exRecConErr name)
+ ; let { (field_names, btys) = unzip fields }
+ ; tc_datacon False field_names btys } }
+
+tcConDecl unbox_strict DataType tycon tc_tvs -- GADTs
+ decl@(GadtDecl name con_ty)
+ = do { traceTc (text "tcConDecl" <+> ppr name)
+ ; (tvs, theta, bangs, arg_tys, tc, res_tys) <- tcLHsConSig con_ty
+
+ ; traceTc (text "tcConDecl1" <+> ppr name)
+ ; let -- Now dis-assemble the type, and check its form
+ is_vanilla = null theta && mkTyVarTys tvs `tcEqTypes` res_tys
+
+ -- Vanilla datacons guarantee to use the same
+ -- type variables as the parent tycon
+ (tvs', arg_tys', res_tys')
+ | is_vanilla = (tc_tvs, substTys subst arg_tys, substTys subst res_tys)
+ | otherwise = (tvs, arg_tys, res_tys)
+ subst = zipTopTvSubst tvs (mkTyVarTys tc_tvs)
+
+ ; traceTc (text "tcConDecl3" <+> ppr name)
+ ; buildDataCon (unLoc name) False {- Not infix -} is_vanilla
+ (argStrictness unbox_strict tycon bangs arg_tys)
+ [{- No field labels -}]
+ tvs' theta arg_tys' tycon res_tys' }
+
+-------------------
+tcStupidTheta :: LHsContext Name -> [LConDecl Name] -> TcM (Maybe ThetaType)
+-- For GADTs we don't allow a context on the data declaration
+-- whereas for standard Haskell style data declarations, we do
+tcStupidTheta ctxt (L _ (ConDecl _ _ _ _) : _)
+ = do { theta <- tcHsKindedContext ctxt; return (Just theta) }
+tcStupidTheta ctxt other -- Includes an empty constructor list
+ = ASSERT( null (unLoc ctxt) ) return Nothing
+
+-------------------
+argStrictness :: Bool -- True <=> -funbox-strict_fields
+ -> TyCon -> [HsBang]
+ -> [TcType] -> [StrictnessMark]
+argStrictness unbox_strict tycon bangs arg_tys
+ = ASSERT( length bangs == length arg_tys )
+ zipWith (chooseBoxingStrategy unbox_strict tycon) arg_tys bangs
+
+-- We attempt to unbox/unpack a strict field when either:
+-- (i) The field is marked '!!', or
+-- (ii) The field is marked '!', and the -funbox-strict-fields flag is on.
+
+chooseBoxingStrategy :: Bool -> TyCon -> TcType -> HsBang -> StrictnessMark
+chooseBoxingStrategy unbox_strict_fields tycon arg_ty bang
+ = case bang of
+ HsNoBang -> NotMarkedStrict
+ HsStrict | unbox_strict_fields && can_unbox -> MarkedUnboxed
+ HsUnbox | can_unbox -> MarkedUnboxed
+ other -> MarkedStrict
+ where
+ can_unbox = case splitTyConApp_maybe arg_ty of
+ Nothing -> False
+ Just (arg_tycon, _) -> not (isRecursiveTyCon tycon) &&
+ isProductTyCon arg_tycon
+\end{code}
-get_deriv Nothing = emptyUniqSet
-get_deriv (Just clss) = unionManyUniqSets (map set_name clss)
+%************************************************************************
+%* *
+\subsection{Dependency analysis}
+%* *
+%************************************************************************
-get_cons cons = unionManyUniqSets (map get_con cons)
+Validity checking is done once the mutually-recursive knot has been
+tied, so we can look at things freely.
-get_con (ConDecl _ ctxt details _)
- = get_ctxt ctxt `unionUniqSets` get_con_details details
+\begin{code}
+checkCycleErrs :: [LTyClDecl Name] -> TcM ()
+checkCycleErrs tyclss
+ | null cls_cycles
+ = return ()
+ | otherwise
+ = do { mappM_ recClsErr cls_cycles
+ ; failM } -- Give up now, because later checkValidTyCl
+ -- will loop if the synonym is recursive
+ where
+ cls_cycles = calcClassCycles tyclss
+
+checkValidTyCl :: TyClDecl Name -> TcM ()
+-- We do the validity check over declarations, rather than TyThings
+-- only so that we can add a nice context with tcAddDeclCtxt
+checkValidTyCl decl
+ = tcAddDeclCtxt decl $
+ do { thing <- tcLookupLocatedGlobal (tcdLName decl)
+ ; traceTc (text "Validity of" <+> ppr thing)
+ ; case thing of
+ ATyCon tc -> checkValidTyCon tc
+ AClass cl -> checkValidClass cl
+ ; traceTc (text "Done validity of" <+> ppr thing)
+ }
+
+-------------------------
+checkValidTyCon :: TyCon -> TcM ()
+checkValidTyCon tc
+ | isSynTyCon tc
+ = checkValidType syn_ctxt syn_rhs
+ | otherwise
+ = -- Check the context on the data decl
+ checkValidTheta (DataTyCtxt name) (tyConStupidTheta tc) `thenM_`
+
+ -- Check arg types of data constructors
+ mappM_ (checkValidDataCon tc) data_cons `thenM_`
+
+ -- Check that fields with the same name share a type
+ mappM_ check_fields groups
-get_con_details (VanillaCon btys) = unionManyUniqSets (map get_bty btys)
-get_con_details (InfixCon bty1 bty2) = unionUniqSets (get_bty bty1) (get_bty bty2)
-get_con_details (NewCon ty) = get_ty ty
-get_con_details (RecCon nbtys) = unionManyUniqSets (map (get_bty.snd) nbtys)
+ where
+ syn_ctxt = TySynCtxt name
+ name = tyConName tc
+ (_, syn_rhs) = getSynTyConDefn tc
+ data_cons = tyConDataCons tc
+
+ groups = equivClasses cmp_fld (concatMap get_fields data_cons)
+ cmp_fld (f1,_) (f2,_) = f1 `compare` f2
+ get_fields con = dataConFieldLabels con `zip` dataConOrigArgTys con
+ -- dataConFieldLabels may return the empty list, which is fine
+
+ check_fields fields@((first_field_label, field_ty) : other_fields)
+ -- These fields all have the same name, but are from
+ -- different constructors in the data type
+ = -- Check that all the fields in the group have the same type
+ -- NB: this check assumes that all the constructors of a given
+ -- data type use the same type variables
+ checkTc (all (tcEqType field_ty . snd) other_fields)
+ (fieldTypeMisMatch first_field_label)
+
+-------------------------------
+checkValidDataCon :: TyCon -> DataCon -> TcM ()
+checkValidDataCon tc con
+ = addErrCtxt (dataConCtxt con) $
+ do { checkTc (dataConTyCon con == tc) (badDataConTyCon con)
+ ; checkValidType ctxt (idType (dataConWrapId con)) }
+
+ -- This checks the argument types and
+ -- ambiguity of the existential context (if any)
+ --
+ -- Note [Sept 04] Now that tvs is all the tvs, this
+ -- test doesn't actually check anything
+-- ; checkFreeness tvs ex_theta }
+ where
+ ctxt = ConArgCtxt (dataConName con)
+ (tvs, ex_theta, _, _, _) = dataConSig con
-get_bty (Banged ty) = get_ty ty
-get_bty (Unbanged ty) = get_ty ty
-get_ty (MonoTyVar name)
- = if isTvOcc (nameOccName name) then emptyUniqSet else set_name name
-get_ty (MonoTyApp ty1 ty2)
- = unionUniqSets (get_ty ty1) (get_ty ty2)
-get_ty (MonoFunTy ty1 ty2)
- = unionUniqSets (get_ty ty1) (get_ty ty2)
-get_ty (MonoListTy tc ty)
- = set_name tc `unionUniqSets` get_ty ty
-get_ty (MonoTupleTy tc tys)
- = set_name tc `unionUniqSets` get_tys tys
-get_ty (HsForAllTy _ ctxt mty)
- = get_ctxt ctxt `unionUniqSets` get_ty mty
-get_ty other = panic "TcTyClsDecls:get_ty"
+-------------------------------
+checkValidClass :: Class -> TcM ()
+checkValidClass cls
+ = do { -- CHECK ARITY 1 FOR HASKELL 1.4
+ gla_exts <- doptM Opt_GlasgowExts
-get_tys tys
- = unionManyUniqSets (map get_ty tys)
+ -- Check that the class is unary, unless GlaExs
+ ; checkTc (notNull tyvars) (nullaryClassErr cls)
+ ; checkTc (gla_exts || unary) (classArityErr cls)
-get_sigs sigs
- = unionManyUniqSets (map get_sig sigs)
- where
- get_sig (ClassOpSig _ _ ty _) = get_ty ty
- get_sig other = panic "TcTyClsDecls:get_sig"
+ -- Check the super-classes
+ ; checkValidTheta (ClassSCCtxt (className cls)) theta
-set_name name = unitUniqSet (uniqueOf name)
+ -- Check the class operations
+ ; mappM_ check_op op_stuff
-set_to_bag set = listToBag (uniqSetToList set)
-\end{code}
+ -- Check that if the class has generic methods, then the
+ -- class has only one parameter. We can't do generic
+ -- multi-parameter type classes!
+ ; checkTc (unary || no_generics) (genericMultiParamErr cls)
+ }
+ where
+ (tyvars, theta, _, op_stuff) = classBigSig cls
+ unary = isSingleton tyvars
+ no_generics = null [() | (_, GenDefMeth) <- op_stuff]
+ check_op (sel_id, dm)
+ = addErrCtxt (classOpCtxt sel_id tau) $ do
+ { checkValidTheta SigmaCtxt (tail theta)
+ -- The 'tail' removes the initial (C a) from the
+ -- class itself, leaving just the method type
-get_binders
-~~~~~~~~~~~
-Extract *binding* names from type and class decls. Type variables are
-bound in type, data, newtype and class declarations and the polytypes
-in the class op sigs.
+ ; checkValidType (FunSigCtxt op_name) tau
-Why do we need to grab all these type variables at once, including
-those locally-quantified type variables in class op signatures?
-Because we can only commit to the final kind of a type variable when
-we've completed the mutually recursive group. For example:
+ -- Check that the type mentions at least one of
+ -- the class type variables
+ ; checkTc (any (`elemVarSet` tyVarsOfType tau) tyvars)
+ (noClassTyVarErr cls sel_id)
-class C a where
- op :: D b => a -> b -> b
+ -- Check that for a generic method, the type of
+ -- the method is sufficiently simple
+ ; checkTc (dm /= GenDefMeth || validGenericMethodType tau)
+ (badGenericMethodType op_name op_ty)
+ }
+ where
+ op_name = idName sel_id
+ op_ty = idType sel_id
+ (_,theta,tau) = tcSplitSigmaTy op_ty
-class D c where
- bop :: (Monad c) => ...
-Here, the kind of the locally-polymorphic type variable "b"
-depends on *all the uses of class D*. For example, the use of
-Monad c in bop's type signature means that D must have kind Type->Type.
+---------------------------------------------------------------------
+fieldTypeMisMatch field_name
+ = sep [ptext SLIT("Different constructors give different types for field"), quotes (ppr field_name)]
-\begin{code}
-get_binders :: Bag RenamedHsDecl
- -> ([HsTyVar Name], -- TyVars; no dups
- [(Name, Maybe Arity)], -- Tycons; no dups; arities for synonyms
- [Name]) -- Classes; no dups
+dataConCtxt con = sep [ptext SLIT("When checking the data constructor:"),
+ nest 2 (ex_part <+> pprThetaArrow ex_theta <+> ppr con <+> arg_part)]
+ where
+ (ex_tvs, ex_theta, arg_tys, _, _) = dataConSig con
+ ex_part | null ex_tvs = empty
+ | otherwise = ptext SLIT("forall") <+> hsep (map ppr ex_tvs) <> dot
+ -- The 'ex_theta' part could be non-empty, if the user (bogusly) wrote
+ -- data T a = Eq a => T a a
+ -- So we make sure to print it
+
+ fields = dataConFieldLabels con
+ arg_part | null fields = sep (map pprParendType arg_tys)
+ | otherwise = braces (sep (punctuate comma
+ [ ppr n <+> dcolon <+> ppr ty
+ | (n,ty) <- fields `zip` arg_tys]))
+
+classOpCtxt sel_id tau = sep [ptext SLIT("When checking the class method:"),
+ nest 2 (ppr sel_id <+> dcolon <+> ppr tau)]
+
+nullaryClassErr cls
+ = ptext SLIT("No parameters for class") <+> quotes (ppr cls)
+
+classArityErr cls
+ = vcat [ptext SLIT("Too many parameters for class") <+> quotes (ppr cls),
+ parens (ptext SLIT("Use -fglasgow-exts to allow multi-parameter classes"))]
+
+noClassTyVarErr clas op
+ = sep [ptext SLIT("The class method") <+> quotes (ppr op),
+ ptext SLIT("mentions none of the type variables of the class") <+>
+ ppr clas <+> hsep (map ppr (classTyVars clas))]
+
+genericMultiParamErr clas
+ = ptext SLIT("The multi-parameter class") <+> quotes (ppr clas) <+>
+ ptext SLIT("cannot have generic methods")
+
+badGenericMethodType op op_ty
+ = hang (ptext SLIT("Generic method type is too complex"))
+ 4 (vcat [ppr op <+> dcolon <+> ppr op_ty,
+ ptext SLIT("You can only use type variables, arrows, lists, and tuples")])
+
+recSynErr syn_decls
+ = setSrcSpan (getLoc (head sorted_decls)) $
+ addErr (sep [ptext SLIT("Cycle in type synonym declarations:"),
+ nest 2 (vcat (map ppr_decl sorted_decls))])
+ where
+ sorted_decls = sortLocated syn_decls
+ ppr_decl (L loc decl) = ppr loc <> colon <+> ppr decl
-get_binders decls = (bagToList tyvars, bagToList tycons, bagToList classes)
+recClsErr cls_decls
+ = setSrcSpan (getLoc (head sorted_decls)) $
+ addErr (sep [ptext SLIT("Cycle in class declarations (via superclasses):"),
+ nest 2 (vcat (map ppr_decl sorted_decls))])
where
- (tyvars, tycons, classes) = foldBag union3 get_binders1
- (emptyBag,emptyBag,emptyBag)
- decls
-
- union3 (a1,a2,a3) (b1,b2,b3)
- = (a1 `unionBags` b1, a2 `unionBags` b2, a3 `unionBags` b3)
-
-get_binders1 (TyD (TyData _ _ name tyvars _ _ _ _))
- = (listToBag tyvars, unitBag (name,Nothing), emptyBag)
-get_binders1 (TyD (TySynonym name tyvars _ _))
- = (listToBag tyvars, unitBag (name, Just (length tyvars)), emptyBag)
-get_binders1 (ClD (ClassDecl _ name tyvar sigs _ _ _))
- = (unitBag tyvar `unionBags` sigs_tvs sigs,
- emptyBag, unitBag name)
-
-sigs_tvs sigs = unionManyBags (map sig_tvs sigs)
- where
- sig_tvs (ClassOpSig _ _ ty _) = pty_tvs ty
- pty_tvs (HsForAllTy tvs _ _) = listToBag tvs -- tvs doesn't include the class tyvar
- pty_tvs other = emptyBag
-\end{code}
+ sorted_decls = sortLocated cls_decls
+ ppr_decl (L loc decl) = ppr loc <> colon <+> ppr (decl { tcdSigs = [] })
+sortLocated :: [Located a] -> [Located a]
+sortLocated things = sortLe le things
+ where
+ le (L l1 _) (L l2 _) = l1 <= l2
-\begin{code}
-typeCycleErr syn_cycles sty
- = vcat (map (pp_cycle sty "Cycle in type declarations ...") syn_cycles)
+exRecConErr name
+ = ptext SLIT("Can't combine named fields with locally-quantified type variables or context")
+ $$
+ (ptext SLIT("In the declaration of data constructor") <+> ppr name)
-classCycleErr cls_cycles sty
- = vcat (map (pp_cycle sty "Cycle in class declarations ...") cls_cycles)
+badDataConTyCon data_con
+ = hang (ptext SLIT("Data constructor does not return its parent type:"))
+ 2 (ppr data_con)
-pp_cycle sty str decls
- = hang (text str)
- 4 (vcat (map pp_decl decls))
- where
- pp_decl decl
- = hsep [ppr sty name, ppr sty (getSrcLoc name)]
- where
- name = hsDeclName decl
+badGadtDecl tc_name
+ = vcat [ ptext SLIT("Illegal generalised algebraic data declaration for") <+> quotes (ppr tc_name)
+ , nest 2 (parens $ ptext SLIT("Use -fglasgow-exts to allow GADTs")) ]
\end{code}
projects / ghc-hetmet.git / blobdiff