%
-% (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
-import Ubiq{-uitous-}
+#include "HsVersions.h"
-import HsSyn ( TyDecl(..), ConDecl(..), BangType(..),
- ClassDecl(..), MonoType(..), PolyType(..),
- Sig(..), MonoBinds, Fake, InPat, HsBinds(..), Bind, HsExpr )
-import RnHsSyn ( isRnTyCon, RenamedTyDecl(..), RenamedClassDecl(..),
- RnName(..){-instance Uniquable-}
+import HsSyn ( TyClDecl(..), HsConDetails(..), HsTyVarBndr(..),
+ ConDecl(..), Sig(..), BangType(..), HsBang(..),
+ tyClDeclTyVars, getBangType, getBangStrictness,
+ LTyClDecl, tcdName, LHsTyVarBndr
)
-import TcHsSyn ( TcHsBinds(..), TcIdOcc(..) )
-
-import TcMonad
-import Inst ( InstanceMapper(..) )
-import TcClassDcl ( tcClassDecl1 )
-import TcEnv ( tcExtendTyConEnv, tcExtendClassEnv,
- tcExtendGlobalValEnv,
- tcTyVarScope, tcGetEnv )
-import TcKind ( TcKind, newKindVars )
-import TcTyDecls ( tcTyDecl, mkDataBinds )
-
-import Bag
-import Class ( Class(..), classSelIds )
-import Digraph ( findSCCs, SCC(..) )
-import Name ( getSrcLoc )
-import PprStyle
-import Pretty
-import UniqSet ( UniqSet(..), emptyUniqSet,
- unitUniqSet, unionUniqSets,
- unionManyUniqSets, uniqSetToList )
-import SrcLoc ( SrcLoc )
-import TyCon ( TyCon, tyConDataCons, isDataTyCon, isSynTyCon )
-import Unique ( Unique )
-import Util ( panic, pprTrace )
-
+import BasicTypes ( RecFlag(..), NewOrData(..), StrictnessMark(..) )
+import HscTypes ( implicitTyThings )
+import BuildTyCl ( buildClass, buildAlgTyCon, buildSynTyCon, buildDataCon )
+import TcRnMonad
+import TcEnv ( TcTyThing(..), TyThing(..),
+ tcLookupLocated, tcLookupLocatedGlobal,
+ tcExtendGlobalEnv,
+ tcExtendRecEnv, tcLookupTyVar )
+import TcTyDecls ( calcTyConArgVrcs, calcRecFlags, calcCycleErrs )
+import TcClassDcl ( tcClassSigs, tcAddDeclCtxt )
+import TcHsType ( kcHsTyVars, kcHsLiftedSigType, kcHsSigType, kcCheckHsType,
+ kcHsContext, tcTyVarBndrs, tcHsKindedType, tcHsKindedContext )
+import TcMType ( newKindVar, checkValidTheta, checkValidType, checkFreeness,
+ UserTypeCtxt(..), SourceTyCtxt(..) )
+import TcUnify ( unifyKind )
+import TcType ( TcKind, ThetaType, TcType, tyVarsOfType,
+ mkArrowKind, liftedTypeKind,
+ tcSplitSigmaTy, tcEqType )
+import Type ( splitTyConApp_maybe, pprThetaArrow, pprParendType )
+import FieldLabel ( fieldLabelName, fieldLabelType )
+import Generics ( validGenericMethodType, canDoGenerics )
+import Class ( Class, className, classTyCon, DefMeth(..), classBigSig, classTyVars )
+import TyCon ( TyCon, ArgVrcs, DataConDetails(..),
+ tyConDataCons, mkForeignTyCon, isProductTyCon, isRecursiveTyCon,
+ tyConTheta, getSynTyConDefn, tyConDataCons, isSynTyCon, tyConName )
+import DataCon ( DataCon, dataConWrapId, dataConName, dataConSig, dataConFieldLabels )
+import Var ( TyVar, idType, idName )
+import VarSet ( elemVarSet )
+import Name ( Name, getSrcLoc )
+import Outputable
+import Util ( zipLazy, isSingleton, notNull )
+import SrcLoc ( srcLocSpan, Located(..), unLoc )
+import ListSetOps ( equivClasses )
+import CmdLineOpts ( DynFlag( Opt_GlasgowExts, Opt_Generics, Opt_UnboxStrictFields ) )
\end{code}
-The main function
-~~~~~~~~~~~~~~~~~
-\begin{code}
-data Decl = TyD RenamedTyDecl | ClD RenamedClassDecl
-tcTyAndClassDecls1 :: InstanceMapper
- -> Bag RenamedTyDecl -> Bag RenamedClassDecl
- -> TcM s (TcEnv s, TcHsBinds s)
+%************************************************************************
+%* *
+\subsection{Type checking for type and class declarations}
+%* *
+%************************************************************************
-tcTyAndClassDecls1 inst_mapper rnty_decls rncls_decls
- = sortByDependency syn_decls cls_decls decls `thenTc` \ groups ->
- tcGroups inst_mapper groups
+Dealing with a group
+~~~~~~~~~~~~~~~~~~~~
+Consider a mutually-recursive group, binding
+a type constructor T and a class C.
+
+Step 1: getInitialKind
+ Construct a KindEnv by binding T and C to a kind variable
+
+Step 2: kcTyClDecl
+ In that environment, do a kind check
+
+Step 3: Zonk the kinds
+
+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
+
+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.
+
+
+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
+
+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.
+
+
+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.
+
+\begin{code}
+tcTyAndClassDecls :: [LTyClDecl Name]
+ -> TcM TcGblEnv -- Input env extended by types and classes
+ -- and their implicit Ids,DataCons
+tcTyAndClassDecls decls
+ = do { -- First check for cyclic type synonysm or classes
+ -- See notes with checkCycleErrs
+ checkCycleErrs decls
+
+ ; let { udecls = map unLoc decls }
+ ; tyclss <- fixM (\ rec_tyclss ->
+ do { lcl_things <- mappM getInitialKind udecls
+ -- Extend the local env with kinds, and
+ -- the global env with the knot-tied results
+ ; let { gbl_things = mkGlobalThings udecls rec_tyclss }
+ ; tcExtendRecEnv gbl_things lcl_things $ do
+
+ -- The local type environment is populated with
+ -- {"T" -> ARecTyCon k, ...}
+ -- and the global type envt with
+ -- {"T" -> ATyCon T, ...}
+ -- where k is T's (unzonked) kind
+ -- T is the loop-tied TyCon itself
+ -- 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
+
+ -- Kind-check the declarations, returning kind-annotated decls
+ { kc_decls <- mappM kcTyClDecl decls
+
+ -- Calculate variances and rec-flag
+ ; let { calc_vrcs = calcTyConArgVrcs rec_tyclss
+ ; calc_rec = calcRecFlags rec_tyclss }
+
+ ; mappM (tcTyClDecl calc_vrcs calc_rec) kc_decls
+ }})
+ -- Finished with knot-tying now
+ -- Extend the environment with the finished things
+ ; tcExtendGlobalEnv tyclss $ do
+
+ -- Perform the validity check
+ { traceTc (text "ready for validity check")
+ ; mappM_ 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 tyclss }
+ ; traceTc ((text "Adding" <+> ppr tyclss) $$ (text "and" <+> ppr implicit_things))
+ ; tcExtendGlobalEnv implicit_things getGblEnv
+ }}
+
+mkGlobalThings :: [TyClDecl 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
- cls_decls = mapBag ClD rncls_decls
- ty_decls = mapBag TyD rnty_decls
- syn_decls = filterBag is_syn_decl ty_decls
- decls = ty_decls `unionBags` cls_decls
+ mk_thing (ClassDecl {tcdLName = L _ name}, ~(AClass cl))
+ = (name, AClass cl)
+ mk_thing (decl, ~(ATyCon tc))
+ = (tcdName decl, ATyCon tc)
+\end{code}
- is_syn_decl (TyD (TySynonym _ _ _ _)) = True
- is_syn_decl _ = False
-tcGroups inst_mapper []
- = tcGetEnv `thenNF_Tc` \ env ->
- returnTc (env, EmptyBinds)
+%************************************************************************
+%* *
+ Kind checking
+%* *
+%************************************************************************
-tcGroups inst_mapper (group:groups)
- = tcGroup inst_mapper group `thenTc` \ (new_env, binds1) ->
+We need to kind check all types in the mutually recursive group
+before we know the kind of the type variables. For example:
- -- Extend the environment using the new tycons and classes
- tcSetEnv new_env $
+class C a where
+ op :: D b => a -> b -> b
- -- Do the remaining groups
- tcGroups inst_mapper groups `thenTc` \ (final_env, binds2) ->
+class D c where
+ bop :: (Monad c) => ...
- returnTc (final_env, binds1 `ThenBinds` binds2)
-\end{code}
+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.
-Dealing with a group
-~~~~~~~~~~~~~~~~~~~~
\begin{code}
-tcGroup :: InstanceMapper -> Bag Decl -> TcM s (TcEnv s, TcHsBinds s)
-tcGroup inst_mapper decls
- = --pprTrace "tcGroup: " (ppCat (map (fst.fmt_decl) (bagToList decls))) $
-
- -- TIE THE KNOT
- fixTc ( \ ~(tycons,classes,_) ->
-
- -- EXTEND TYPE AND CLASS ENVIRONMENTS
- -- including their data constructors and class operations
- -- 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 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` \ (tycons, classes, final_env) ->
-
-
- -- Create any necessary record selector Ids and their bindings
- -- "Necessary" includes data and newtype declarations
- mapAndUnzipTc mkDataBinds (filter (not.isSynTyCon) tycons) `thenTc` \ (data_ids_s, binds) ->
-
- -- Extend the global value environment with
- -- a) constructors
- -- b) record selectors
- -- c) class op selectors
+------------------------------------------------------------------------
+getInitialKind :: TyClDecl Name -> TcM (Name, TcTyThing)
- tcSetEnv final_env $
- tcExtendGlobalValEnv (concat data_ids_s) $
- tcExtendGlobalValEnv (concat (map classSelIds classes)) $
- tcGetEnv `thenNF_Tc` \ really_final_env ->
+-- Note the lazy pattern match on the ATyCon etc
+-- Exactly the same reason as the zipLay above
- returnTc (really_final_env, foldr ThenBinds EmptyBinds binds)
+getInitialKind (TyData {tcdLName = L _ name})
+ = newKindVar `thenM` \ kind ->
+ returnM (name, ARecTyCon kind)
- where
- (tyvar_rn_names, tycon_names_w_arities, class_names) = get_binders decls
+getInitialKind (TySynonym {tcdLName = L _ name})
+ = newKindVar `thenM` \ kind ->
+ returnM (name, ARecTyCon kind)
- tyvar_names = map de_rn tyvar_rn_names
- de_rn (RnName n) = n
+getInitialKind (ClassDecl {tcdLName = L _ name})
+ = newKindVar `thenM` \ kind ->
+ returnM (name, ARecClass kind)
- combine do_a do_b
- = do_a `thenTc` \ (a1,a2) ->
- do_b `thenTc` \ (b1,b2) ->
- returnTc (a1 `unionBags` b1, a2 `unionBags` b2)
-\end{code}
-Dealing with one decl
-~~~~~~~~~~~~~~~~~~~~~
-\begin{code}
-tcDecl :: InstanceMapper
- -> Decl
- -> TcM s (Bag TyCon, Bag Class)
+------------------------------------------------------------------------
+kcTyClDecl :: LTyClDecl Name -> TcM (LTyClDecl Name)
-tcDecl inst_mapper (TyD decl)
- = tcTyDecl decl `thenTc` \ tycon ->
- returnTc (unitBag tycon, emptyBag)
+kcTyClDecl decl@(L loc d@(TySynonym {tcdSynRhs = rhs}))
+ = do { res_kind <- newKindVar
+ ; kcTyClDeclBody decl res_kind $ \ tvs' ->
+ do { rhs' <- kcCheckHsType rhs res_kind
+ ; return (L loc d{tcdTyVars = tvs', tcdSynRhs = rhs'}) } }
-tcDecl inst_mapper (ClD decl)
- = tcClassDecl1 inst_mapper decl `thenTc` \ clas ->
- returnTc (emptyBag, unitBag clas)
+kcTyClDecl decl@(L loc d@(TyData {tcdND = new_or_data, tcdCtxt = ctxt, tcdCons = cons}))
+ = kcTyClDeclBody decl liftedTypeKind $ \ tvs' ->
+ do { ctxt' <- kcHsContext ctxt
+ ; cons' <- mappM (wrapLocM kc_con_decl) cons
+ ; return (L loc d{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_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 = wrapLocM kc_arg_ty
+
+ kc_arg_ty (BangType str ty) = do { ty' <- kc_arg_ty_body ty; return (BangType str ty') }
+ kc_arg_ty_body = case new_or_data of
+ DataType -> kcHsSigType
+ NewType -> kcHsLiftedSigType
+ -- Can't allow an unlifted type for newtypes, because we're effectively
+ -- going to remove the constructor while coercing it to a lifted type.
+
+kcTyClDecl decl@(L loc d@(ClassDecl {tcdCtxt = ctxt, tcdSigs = sigs}))
+ = kcTyClDeclBody decl liftedTypeKind $ \ tvs' ->
+ do { ctxt' <- kcHsContext ctxt
+ ; sigs' <- mappM (wrapLocM kc_sig) sigs
+ ; return (L loc d{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@(L _ (ForeignType {}))
+ = return decl
+
+kcTyClDeclBody :: LTyClDecl Name -> TcKind
+ -> ([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 res_kind thing_inside
+ = tcAddDeclCtxt decl $
+ kcHsTyVars (tyClDeclTyVars (unLoc decl)) $ \ kinded_tvs ->
+ do { tc_ty_thing <- tcLookupLocated (tcdLName (unLoc decl))
+ ; let { tc_kind = case tc_ty_thing of
+ ARecClass k -> k
+ ARecTyCon k -> k
+ }
+ ; unifyKind tc_kind (foldr (mkArrowKind . kindedTyVarKind)
+ res_kind kinded_tvs)
+ ; thing_inside kinded_tvs }
+
+kindedTyVarKind (L _ (KindedTyVar _ k)) = k
\end{code}
-Dependency analysis
-~~~~~~~~~~~~~~~~~~~
+
+%************************************************************************
+%* *
+\subsection{Type checking}
+%* *
+%************************************************************************
+
\begin{code}
-sortByDependency :: Bag Decl -> Bag Decl -> Bag Decl -> TcM s [Bag Decl]
-sortByDependency syn_decls cls_decls decls
- = let -- CHECK FOR SYNONYM CYCLES
- syn_sccs = findSCCs mk_edges syn_decls
- syn_cycles = [map fmt_decl (bagToList decls)
- | CyclicSCC decls <- syn_sccs]
-
- in
- checkTc (null syn_cycles) (typeCycleErr syn_cycles) `thenTc_`
-
- let -- CHECK FOR CLASS CYCLES
- cls_sccs = findSCCs mk_edges cls_decls
- cls_cycles = [map fmt_decl (bagToList decls)
- | CyclicSCC decls <- cls_sccs]
-
- in
- checkTc (null cls_cycles) (classCycleErr cls_cycles) `thenTc_`
-
- -- DO THE MAIN DEPENDENCY ANALYSIS
- let
- decl_sccs = findSCCs mk_edges decls
- scc_bags = map bag_acyclic decl_sccs
- in
- returnTc (scc_bags)
-
- where
- bag_acyclic (AcyclicSCC scc) = unitBag scc
- bag_acyclic (CyclicSCC sccs) = sccs
+tcTyClDecl :: (Name -> ArgVrcs) -> (Name -> RecFlag)
+ -> LTyClDecl Name -> TcM TyThing
-fmt_decl decl
- = (ppr PprForUser name, getSrcLoc name)
+tcTyClDecl calc_vrcs calc_isrec decl
+ = tcAddDeclCtxt decl (tcTyClDecl1 calc_vrcs calc_isrec (unLoc decl))
+
+tcTyClDecl1 calc_vrcs calc_isrec
+ (TySynonym {tcdLName = L _ tc_name, tcdTyVars = tvs, tcdSynRhs = rhs_ty})
+ = tcTyVarBndrs tvs $ \ tvs' -> do
+ { rhs_ty' <- tcHsKindedType rhs_ty
+ ; return (ATyCon (buildSynTyCon tc_name tvs' rhs_ty' arg_vrcs)) }
+ where
+ arg_vrcs = calc_vrcs tc_name
+
+tcTyClDecl1 calc_vrcs calc_isrec
+ (TyData {tcdND = new_or_data, tcdCtxt = ctxt, tcdTyVars = tvs,
+ tcdLName = L _ tc_name, tcdCons = cons})
+ = tcTyVarBndrs tvs $ \ tvs' -> do
+ { ctxt' <- tcHsKindedContext ctxt
+ ; want_generic <- doptM Opt_Generics
+ ; tycon <- fixM (\ tycon -> do
+ { cons' <- mappM (addLocM (tcConDecl new_or_data tycon tvs' ctxt')) cons
+ ; buildAlgTyCon new_or_data tc_name tvs' ctxt'
+ (DataCons cons') arg_vrcs is_rec
+ (want_generic && canDoGenerics cons')
+ })
+ ; return (ATyCon tycon)
+ }
+ where
+ arg_vrcs = calc_vrcs tc_name
+ is_rec = calc_isrec tc_name
+
+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 :: NewOrData -> TyCon -> [TyVar] -> ThetaType
+ -> ConDecl Name -> TcM DataCon
+
+tcConDecl new_or_data tycon tyvars ctxt
+ (ConDecl name ex_tvs ex_ctxt details)
+ = tcTyVarBndrs ex_tvs $ \ ex_tvs' -> do
+ { ex_ctxt' <- tcHsKindedContext ex_ctxt
+ ; unbox_strict <- doptM Opt_UnboxStrictFields
+ ; let
+ tc_datacon field_lbls btys
+ = do { let { ubtys = map unLoc btys }
+ ; arg_tys <- mappM (tcHsKindedType . getBangType) ubtys
+ ; buildDataCon (unLoc name)
+ (argStrictness unbox_strict tycon ubtys arg_tys)
+ (map unLoc field_lbls)
+ tyvars ctxt ex_tvs' ex_ctxt'
+ arg_tys tycon }
+ ; case details of
+ PrefixCon btys -> tc_datacon [] btys
+ InfixCon bty1 bty2 -> tc_datacon [] [bty1,bty2]
+ RecCon fields -> do { checkTc (null ex_tvs') (exRecConErr name)
+ ; let { (field_names, btys) = unzip fields }
+ ; tc_datacon field_names btys } }
+
+argStrictness :: Bool -- True <=> -funbox-strict_fields
+ -> TyCon -> [BangType Name]
+ -> [TcType] -> [StrictnessMark]
+argStrictness unbox_strict tycon btys arg_tys
+ = zipWith (chooseBoxingStrategy unbox_strict tycon)
+ arg_tys
+ (map getBangStrictness btys ++ repeat HsNoBang)
+
+-- 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
- name = get_name decl
- get_name (TyD (TyData _ name _ _ _ _ _)) = name
- get_name (TyD (TyNew _ name _ _ _ _ _)) = name
- get_name (TyD (TySynonym name _ _ _)) = name
- get_name (ClD (ClassDecl _ name _ _ _ _ _)) = name
+ can_unbox = case splitTyConApp_maybe arg_ty of
+ Nothing -> False
+ Just (arg_tycon, _) -> not (isRecursiveTyCon tycon) &&
+ isProductTyCon arg_tycon
\end{code}
-Edges in Type/Class decls
-~~~~~~~~~~~~~~~~~~~~~~~~~
+%************************************************************************
+%* *
+\subsection{Dependency analysis}
+%* *
+%************************************************************************
+
+Validity checking is done once the mutually-recursive knot has been
+tied, so we can look at things freely.
+
\begin{code}
-mk_edges (TyD (TyData ctxt name _ condecls _ _ _))
- = (uniqueOf name, set_to_bag (get_ctxt ctxt `unionUniqSets` get_cons condecls))
-mk_edges (TyD (TyNew ctxt name _ condecl _ _ _))
- = (uniqueOf name, set_to_bag (get_ctxt ctxt `unionUniqSets` get_cons condecl))
-mk_edges (TyD (TySynonym name _ rhs _))
- = (uniqueOf name, set_to_bag (get_ty rhs))
-mk_edges (ClD (ClassDecl ctxt name _ sigs _ _ _))
- = (uniqueOf name, set_to_bag (get_ctxt ctxt `unionUniqSets` get_sigs sigs))
-
-get_ctxt ctxt
- = unionManyUniqSets (map (set_name.fst) ctxt)
-
-get_cons cons
- = unionManyUniqSets (map get_con cons)
+checkCycleErrs :: [LTyClDecl Name] -> TcM ()
+checkCycleErrs tyclss
+ | null syn_cycles && null cls_cycles
+ = return ()
+ | otherwise
+ = do { mappM_ recSynErr syn_cycles
+ ; mappM_ recClsErr cls_cycles
+ ; failM } -- Give up now, because later checkValidTyCl
+ -- will loop if the synonym is recursive
where
- get_con (ConDecl _ btys _)
- = unionManyUniqSets (map get_bty btys)
- get_con (ConOpDecl bty1 _ bty2 _)
- = unionUniqSets (get_bty bty1) (get_bty bty2)
- get_con (NewConDecl _ ty _)
- = get_ty ty
- get_con (RecConDecl _ nbtys _)
- = unionManyUniqSets (map (get_bty.snd) nbtys)
-
- get_bty (Banged ty) = get_pty ty
- get_bty (Unbanged ty) = get_pty ty
-
-get_ty (MonoTyVar tv)
- = emptyUniqSet
-get_ty (MonoTyApp name tys)
- = (if isRnTyCon name then set_name name else emptyUniqSet)
- `unionUniqSets` get_tys tys
-get_ty (MonoFunTy ty1 ty2)
- = unionUniqSets (get_ty ty1) (get_ty ty2)
-get_ty (MonoListTy ty)
- = get_ty ty -- careful when defining [] (,,) etc as
-get_ty (MonoTupleTy tys) -- [ty] (ty,ty,ty) will not give edges!
- = get_tys tys
-get_ty other = panic "TcTyClsDecls:get_ty"
-
-get_pty (HsForAllTy _ ctxt mty)
- = get_ctxt ctxt `unionUniqSets` get_ty mty
-get_pty other = panic "TcTyClsDecls:get_pty"
-
-get_tys tys
- = unionManyUniqSets (map get_ty tys)
-
-get_sigs sigs
- = unionManyUniqSets (map get_sig sigs)
- where
- get_sig (ClassOpSig _ ty _ _) = get_pty ty
- get_sig other = panic "TcTyClsDecls:get_sig"
-
-set_name name = unitUniqSet (uniqueOf name)
-
-set_to_bag set = listToBag (uniqSetToList set)
-\end{code}
+ (syn_cycles, cls_cycles) = calcCycleErrs tyclss
+
+checkValidTyCl :: LTyClDecl 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 (unLoc 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) (tyConTheta tc) `thenM_`
+
+ -- Check arg types of data constructors
+ mappM_ checkValidDataCon data_cons `thenM_`
+ -- Check that fields with the same name share a type
+ mappM_ check_fields groups
-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.
+ where
+ syn_ctxt = TySynCtxt name
+ name = tyConName tc
+ (_, syn_rhs) = getSynTyConDefn tc
+ data_cons = tyConDataCons tc
+
+ fields = [field | con <- data_cons, field <- dataConFieldLabels con]
+ groups = equivClasses cmp_name fields
+ cmp_name field1 field2 = fieldLabelName field1 `compare` fieldLabelName field2
+
+ check_fields fields@(first_field_label : 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) other_tys) (fieldTypeMisMatch field_name)
+ where
+ field_ty = fieldLabelType first_field_label
+ field_name = fieldLabelName first_field_label
+ other_tys = map fieldLabelType other_fields
+
+-------------------------------
+checkValidDataCon :: DataCon -> TcM ()
+checkValidDataCon con
+ = addErrCtxt (dataConCtxt con) (
+ checkValidType ctxt (idType (dataConWrapId con)) `thenM_`
+ -- This checks the argument types and
+ -- ambiguity of the existential context (if any)
+ checkFreeness ex_tvs ex_theta)
+ where
+ ctxt = ConArgCtxt (dataConName con)
+ (_, _, ex_tvs, ex_theta, _, _) = dataConSig con
-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:
-class C a where
- op :: D b => a -> b -> b
-
-class D c where
- bop :: (Monad c) => ...
+-------------------------------
+checkValidClass :: Class -> TcM ()
+checkValidClass cls
+ = do { -- CHECK ARITY 1 FOR HASKELL 1.4
+ gla_exts <- doptM Opt_GlasgowExts
-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.
+ -- Check that the class is unary, unless GlaExs
+ ; checkTc (notNull tyvars) (nullaryClassErr cls)
+ ; checkTc (gla_exts || unary) (classArityErr cls)
+ -- Check the super-classes
+ ; checkValidTheta (ClassSCCtxt (className cls)) theta
-\begin{code}
-get_binders :: Bag Decl
- -> ([RnName], -- TyVars; no dups
- [(RnName, Maybe Arity)],-- Tycons; no dups; arities for synonyms
- [RnName]) -- Classes; no dups
+ -- Check the class operations
+ ; mappM_ check_op op_stuff
-get_binders decls = (bagToList tyvars, bagToList tycons, bagToList classes)
+ -- 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, 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 (TyNew _ 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
-\end{code}
+ (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
+
+ ; checkValidType (FunSigCtxt op_name) tau
+
+ -- Check that the type mentions at least one of
+ -- the class type variables
+ ; checkTc (any (`elemVarSet` tyVarsOfType tau) tyvars)
+ (noClassTyVarErr cls sel_id)
+
+ -- Check that for a generic method, the type of
+ -- the method is sufficiently simple
+ ; checkTc (dm /= GenDefMeth || validGenericMethodType op_ty)
+ (badGenericMethodType op_name op_ty)
+ }
+ where
+ op_name = idName sel_id
+ op_ty = idType sel_id
+ (_,theta,tau) = tcSplitSigmaTy op_ty
-\begin{code}
-typeCycleErr syn_cycles sty
- = ppAboves (map (pp_cycle sty "Cycle in type declarations ...") syn_cycles)
-classCycleErr cls_cycles sty
- = ppAboves (map (pp_cycle sty "Cycle in class declarations ...") cls_cycles)
+---------------------------------------------------------------------
+fieldTypeMisMatch field_name
+ = sep [ptext SLIT("Different constructors give different types for field"), quotes (ppr field_name)]
-pp_cycle sty str things
- = ppHang (ppStr str)
- 4 (ppAboves (map pp_thing things))
+dataConCtxt con = sep [ptext SLIT("When checking the data constructor:"),
+ nest 2 (ex_part <+> pprThetaArrow ex_theta <+> ppr con <+> arg_part)]
where
- pp_thing (pp_name, loc)
- = ppCat [pp_name, ppr sty loc]
+ (_, _, 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, and tuples")])
+
+recSynErr tcs
+ = addSrcSpan (srcLocSpan (getSrcLoc (head tcs))) $
+ addErr (sep [ptext SLIT("Cycle in type synonym declarations:"),
+ nest 2 (vcat (map ppr_thing tcs))])
+
+recClsErr clss
+ = addSrcSpan (srcLocSpan (getSrcLoc (head clss))) $
+ addErr (sep [ptext SLIT("Cycle in class declarations (via superclasses):"),
+ nest 2 (vcat (map ppr_thing clss))])
+
+ppr_thing :: Name -> SDoc
+ppr_thing n = ppr n <+> parens (ppr (getSrcLoc n))
+
+
+exRecConErr name
+ = ptext SLIT("Can't combine named fields with locally-quantified type variables")
+ $$
+ (ptext SLIT("In the declaration of data constructor") <+> ppr name)
\end{code}
projects / ghc-hetmet.git / blobdiff