#include "HsVersions.h"
-import HsSyn ( TyClDecl(..),
- ConDecl(..), Sig(..), HsPred(..),
- tyClDeclName, hsTyVarNames, tyClDeclTyVars,
- isTypeOrClassDecl, isClassDecl, isSynDecl, isClassOpSig
+import HsSyn ( TyClDecl(..), HsConDetails(..), HsTyVarBndr(..),
+ ConDecl(..), Sig(..), BangType(..), HsBang(..),
+ tyClDeclTyVars, getBangType, getBangStrictness,
+ LTyClDecl, tcdName, LHsTyVarBndr
)
-import RnHsSyn ( RenamedTyClDecl, tyClDeclFVs )
-import RnEnv ( lookupSysName )
-import BasicTypes ( RecFlag(..), NewOrData(..) )
+import BasicTypes ( RecFlag(..), NewOrData(..), StrictnessMark(..) )
import HscTypes ( implicitTyThings )
-
+import BuildTyCl ( buildClass, buildAlgTyCon, buildSynTyCon, buildDataCon )
import TcRnMonad
-import TcEnv ( TcTyThing(..), TyThing(..), TyThingDetails(..),
- tcExtendKindEnv, tcLookup, tcLookupGlobal, tcExtendGlobalEnv,
- isLocalThing )
-import TcTyDecls ( tcTyDecl, kcConDetails )
-import TcClassDcl ( tcClassDecl1 )
-import TcInstDcls ( tcAddDeclCtxt )
-import TcMonoType ( kcHsTyVars, kcHsType, kcHsLiftedSigType, kcHsContext, mkTyClTyVars )
-import TcMType ( newKindVar, zonkKindEnv, checkValidTyCon, checkValidClass )
+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 ( Type, Kind, TcKind, mkArrowKind, liftedTypeKind, zipFunTys )
-import Type ( splitTyConApp_maybe )
-import Variance ( calcTyConArgVrcs )
-import Class ( Class, mkClass, classTyCon )
-import TyCon ( TyCon, ArgVrcs, AlgTyConFlavour(..), DataConDetails(..), visibleDataCons,
- tyConKind, tyConTyVars, tyConDataCons, isNewTyCon,
- mkSynTyCon, mkAlgTyCon, mkClassTyCon, mkForeignTyCon
- )
-import TysWiredIn ( unitTy )
-import Subst ( substTyWith )
-import DataCon ( dataConOrigArgTys )
-import Var ( varName )
-import OccName ( mkClassTyConOcc )
-import FiniteMap
-import Digraph ( stronglyConnComp, SCC(..) )
-import Name ( Name )
-import NameEnv
-import NameSet
+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 Maybes ( mapMaybe, orElse, catMaybes )
+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}
-tcTyAndClassDecls :: [RenamedTyClDecl]
- -> TcM TcGblEnv -- Returns extended environment
-
-tcTyAndClassDecls decls
- = do { edge_map <- mkEdgeMap tc_decls ;
- let { edges = mkEdges edge_map tc_decls } ;
- tcGroups edge_map (stronglyConnComp edges) }
- where
- tc_decls = filter isTypeOrClassDecl decls
-
-tcGroups edge_map [] = getGblEnv
-
-tcGroups edge_map (group:groups)
- = tcGroup edge_map group `thenM` \ env ->
- setGblEnv env $
- tcGroups edge_map groups
-\end{code}
-
Dealing with a group
~~~~~~~~~~~~~~~~~~~~
Consider a mutually-recursive group, binding
@TyThing@s. @rec_vrcs@ is a finite map from @Name@s to @ArgVrcs@s.
\begin{code}
-tcGroup :: EdgeMap -> SCC RenamedTyClDecl
- -> TcM TcGblEnv -- Input env extended by types and classes
- -- and their implicit Ids,DataCons
-
-tcGroup edge_map scc
- = -- Step 1
- mappM getInitialKind decls `thenM` \ initial_kinds ->
-
- -- Step 2
- tcExtendKindEnv initial_kinds (mappM kcTyClDecl decls) `thenM_`
-
- -- Step 3
- zonkKindEnv initial_kinds `thenM` \ final_kinds ->
-
- -- Check for loops; if any are found, bale out now
- -- because the compiler itself will loop otherwise!
- checkNoErrs (checkLoops edge_map scc) `thenM` \ is_rec_tycon ->
-
- -- Tie the knot
- traceTc (text "starting" <+> ppr final_kinds) `thenM_`
- fixM ( \ ~(rec_details_list, _, _) ->
- -- Step 4
- let
- kind_env = mkNameEnv final_kinds
- rec_details = mkNameEnv rec_details_list
-
- -- Calculate variances, and feed into buildTyConOrClass
- rec_vrcs = calcTyConArgVrcs [tc | ATyCon tc <- tyclss]
-
- build_one = buildTyConOrClass is_rec_tycon kind_env
- rec_vrcs rec_details
- tyclss = map build_one decls
-
- in
- -- Step 5
- -- Extend the environment with the final
- -- TyCons/Classes and check the decls
- tcExtendGlobalEnv tyclss $
- mappM tcTyClDecl1 decls `thenM` \ tycls_details ->
-
- -- Return results
- getGblEnv `thenM` \ env ->
- returnM (tycls_details, env, tyclss)
- ) `thenM` \ (_, env, tyclss) ->
-
- -- Step 7: Check validity
- setGblEnv env $
-
- traceTc (text "ready for validity check") `thenM_`
- getModule `thenM` \ mod ->
- mappM_ (checkValidTyCl mod) decls `thenM_`
- traceTc (text "done") `thenM_`
+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")
- let -- Add the tycons that come from the classes
- -- We want them in the environment because
- -- they are mentioned in interface files
- implicit_things = implicitTyThings tyclss
- in
- traceTc ((text "Adding" <+> ppr tyclss) $$ (text "and" <+> ppr implicit_things)) `thenM_`
- tcExtendGlobalEnv implicit_things getGblEnv
-
+ -- Add the implicit things;
+ -- we want them in the environment because
+ -- they may be mentioned in interface files
+ ; let { implicit_things = concatMap implicitTyThings tyclss }
+ ; traceTc ((text "Adding" <+> ppr tyclss) $$ (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
- decls = case scc of
- AcyclicSCC decl -> [decl]
- CyclicSCC decls -> decls
-
-tcTyClDecl1 decl
- | isClassDecl decl = tcAddDeclCtxt decl (tcClassDecl1 decl)
- | otherwise = tcAddDeclCtxt decl (tcTyDecl decl)
-
--- We do the validity check over declarations, rather than TyThings
--- only so that we can add a nice context with tcAddDeclCtxt
-checkValidTyCl this_mod decl
- = tcLookupGlobal (tcdName decl) `thenM` \ thing ->
- if not (isLocalThing this_mod thing) then
- -- Don't bother to check validity for non-local things
- returnM ()
- else
- tcAddDeclCtxt decl $
- case thing of
- ATyCon tc -> checkValidTyCon tc
- AClass cl -> checkValidClass cl
+ mk_thing (ClassDecl {tcdLName = L _ name}, ~(AClass cl))
+ = (name, AClass cl)
+ mk_thing (decl, ~(ATyCon tc))
+ = (tcdName decl, ATyCon tc)
\end{code}
%************************************************************************
%* *
-\subsection{Step 1: Initial environment}
-%* *
-%************************************************************************
-
-\begin{code}
-getInitialKind :: RenamedTyClDecl -> TcM (Name, TcKind)
-getInitialKind decl
- = kcHsTyVars (tyClDeclTyVars decl) `thenM` \ arg_kinds ->
- newKindVar `thenM` \ result_kind ->
- returnM (tcdName decl, mk_kind arg_kinds result_kind)
-
-mk_kind tvs_w_kinds res_kind = foldr (mkArrowKind . snd) res_kind tvs_w_kinds
-\end{code}
-
-
-%************************************************************************
-%* *
-\subsection{Step 2: Kind checking}
+ Kind checking
%* *
%************************************************************************
Monad c in bop's type signature means that D must have kind Type->Type.
\begin{code}
-kcTyClDecl :: RenamedTyClDecl -> TcM ()
+------------------------------------------------------------------------
+getInitialKind :: TyClDecl Name -> TcM (Name, TcTyThing)
+
+-- Note the lazy pattern match on the ATyCon etc
+-- Exactly the same reason as the zipLay above
+
+getInitialKind (TyData {tcdLName = L _ name})
+ = newKindVar `thenM` \ kind ->
+ returnM (name, ARecTyCon kind)
+
+getInitialKind (TySynonym {tcdLName = L _ name})
+ = newKindVar `thenM` \ kind ->
+ returnM (name, ARecTyCon kind)
+
+getInitialKind (ClassDecl {tcdLName = L _ name})
+ = newKindVar `thenM` \ kind ->
+ returnM (name, ARecClass kind)
-kcTyClDecl decl@(TySynonym {tcdSynRhs = rhs})
- = kcTyClDeclBody decl $ \ result_kind ->
- kcHsType rhs `thenM` \ rhs_kind ->
- unifyKind result_kind rhs_kind
-kcTyClDecl (ForeignType {}) = returnM ()
+------------------------------------------------------------------------
+kcTyClDecl :: LTyClDecl Name -> TcM (LTyClDecl Name)
-kcTyClDecl decl@(TyData {tcdND = new_or_data, tcdCtxt = context, tcdCons = con_decls})
- = kcTyClDeclBody decl $ \ result_kind ->
- kcHsContext context `thenM_`
- mappM_ kc_con_decl (visibleDataCons con_decls)
+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'}) } }
+
+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 _ ex_tvs ex_ctxt details loc)
- = kcHsTyVars ex_tvs `thenM` \ kind_env ->
- tcExtendKindEnv kind_env $
- kcConDetails new_or_data ex_ctxt details
-
-kcTyClDecl decl@(ClassDecl {tcdCtxt = context, tcdSigs = class_sigs})
- = kcTyClDeclBody decl $ \ result_kind ->
- kcHsContext context `thenM_`
- mappM_ kc_sig (filter isClassOpSig class_sigs)
+ 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 (ClassOpSig _ _ op_ty loc) = kcHsLiftedSigType op_ty
-
-kcTyClDeclBody :: RenamedTyClDecl -> (Kind -> 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
+ 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 $
- tcLookup (tcdName decl) `thenM` \ thing ->
- let
- kind = case thing of
- AGlobal (ATyCon tc) -> tyConKind tc
- AGlobal (AClass cl) -> tyConKind (classTyCon cl)
- AThing kind -> kind
- -- For some odd reason, a class doesn't include its kind
-
- (tyvars_w_kinds, result_kind) = zipFunTys (hsTyVarNames (tyClDeclTyVars decl)) kind
- in
- tcExtendKindEnv tyvars_w_kinds (thing_inside result_kind)
+ 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}
-
%************************************************************************
%* *
-\subsection{Step 4: Building the tycon/class}
+\subsection{Type checking}
%* *
%************************************************************************
\begin{code}
-buildTyConOrClass
- :: (Name -> AlgTyConFlavour -> RecFlag) -- Whether it's recursive
- -> NameEnv Kind
- -> FiniteMap TyCon ArgVrcs -> NameEnv TyThingDetails
- -> RenamedTyClDecl -> TyThing
-
-buildTyConOrClass rec_tycon kenv rec_vrcs rec_details
- (TySynonym {tcdName = tycon_name, tcdTyVars = tyvar_names})
- = ATyCon tycon
+tcTyClDecl :: (Name -> ArgVrcs) -> (Name -> RecFlag)
+ -> LTyClDecl Name -> TcM TyThing
+
+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
- tycon = mkSynTyCon tycon_name tycon_kind arity tyvars rhs_ty argvrcs
- tycon_kind = lookupNameEnv_NF kenv tycon_name
- arity = length tyvar_names
- tyvars = mkTyClTyVars tycon_kind tyvar_names
- SynTyDetails rhs_ty = lookupNameEnv_NF rec_details tycon_name
- argvrcs = lookupWithDefaultFM rec_vrcs bogusVrcs tycon
-
-buildTyConOrClass rec_tycon kenv rec_vrcs rec_details
- (TyData {tcdND = data_or_new, tcdName = tycon_name,
- tcdTyVars = tyvar_names})
- = ATyCon tycon
+ 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
- tycon = mkAlgTyCon tycon_name tycon_kind tyvars ctxt argvrcs
- data_cons sel_ids flavour
- (rec_tycon tycon_name flavour) gen_info
-
- DataTyDetails ctxt data_cons sel_ids gen_info = lookupNameEnv_NF rec_details tycon_name
-
- tycon_kind = lookupNameEnv_NF kenv tycon_name
- tyvars = mkTyClTyVars tycon_kind tyvar_names
- argvrcs = lookupWithDefaultFM rec_vrcs bogusVrcs tycon
-
- -- Watch out! mkTyConApp asks whether the tycon is a NewType,
- -- so flavour has to be able to answer this question without consulting rec_details
- flavour = case data_or_new of
- NewType -> NewTyCon (mkNewTyConRep tycon)
- DataType | all_nullary data_cons -> EnumTyCon
- | otherwise -> DataTyCon
-
- all_nullary (DataCons cons) = all (null . dataConOrigArgTys) cons
- all_nullary other = False -- Safe choice for unknown data types
- -- NB (null . dataConOrigArgTys). It used to say isNullaryDataCon
- -- but that looks at the *representation* arity, and that in turn
- -- depends on deciding whether to unpack the args, and that
- -- depends on whether it's a data type or a newtype --- so
- -- in the recursive case we can get a loop. This version is simple!
-
-buildTyConOrClass rec_tycon kenv rec_vrcs rec_details
- (ForeignType {tcdName = tycon_name, tcdExtName = tycon_ext_name})
- = ATyCon (mkForeignTyCon tycon_name tycon_ext_name liftedTypeKind 0 [])
-
-buildTyConOrClass rec_tycon kenv rec_vrcs rec_details
- (ClassDecl {tcdName = class_name, tcdTyVars = tyvar_names, tcdFDs = fundeps} )
- = AClass clas
+ 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
- clas = mkClass class_name tyvars fds
- sc_theta sc_sel_ids op_items
- tycon
-
- tycon = mkClassTyCon tycon_name class_kind tyvars
- argvrcs dict_con
- clas -- Yes! It's a dictionary
- flavour
- (rec_tycon class_name flavour)
- -- A class can be recursive, and in the case of newtypes
- -- this matters. For example
- -- class C a where { op :: C b => a -> b -> Int }
- -- Because C has only one operation, it is represented by
- -- a newtype, and it should be a *recursive* newtype.
- -- [If we don't make it a recursive newtype, we'll expand the
- -- newtype like a synonym, but that will lead toan inifinite type
-
- ClassDetails sc_theta sc_sel_ids op_items dict_con tycon_name
- = lookupNameEnv_NF rec_details class_name
-
- class_kind = lookupNameEnv_NF kenv class_name
- tyvars = mkTyClTyVars class_kind tyvar_names
- argvrcs = lookupWithDefaultFM rec_vrcs bogusVrcs tycon
-
- flavour = case dataConOrigArgTys dict_con of
- -- The tyvars in the datacon are the same as in the class
- [rep_ty] -> NewTyCon rep_ty
- other -> DataTyCon
-
- -- We can find the functional dependencies right away,
- -- and it is vital to do so. Why? Because in the next pass
- -- we check for ambiguity in all the type signatures, and we
- -- need the functional dependcies to be done by then
- fds = [(map lookup xs, map lookup ys) | (xs,ys) <- fundeps]
- tyvar_env = mkNameEnv [(varName tv, tv) | tv <- tyvars]
- lookup = lookupNameEnv_NF tyvar_env
-
-bogusVrcs = panic "Bogus tycon arg variances"
-\end{code}
-
-\begin{code}
-mkNewTyConRep :: TyCon -- The original type constructor
- -> Type -- Chosen representation type
- -- (guaranteed not to be another newtype)
-
--- Find the representation type for this newtype TyCon
--- Remember that the representation type is the ultimate representation
--- type, looking through other newtypes.
---
--- The non-recursive newtypes are easy, because they look transparent
--- to splitTyConApp_maybe, but recursive ones really are represented as
--- TyConApps (see TypeRep).
---
--- The trick is to to deal correctly with recursive newtypes
--- such as newtype T = MkT T
-
--- a newtype with no data constructors -- appears in External Core programs
-mkNewTyConRep tc | (null (tyConDataCons tc)) = unitTy
-mkNewTyConRep tc
- = go [] tc
+ 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
- -- Invariant: tc is a NewTyCon
- -- tcs have been seen before
- go tcs tc
- | tc `elem` tcs = unitTy
- | otherwise
- = let
- rep_ty = head (dataConOrigArgTys (head (tyConDataCons tc)))
- in
- case splitTyConApp_maybe rep_ty of
- Nothing -> rep_ty
- Just (tc', tys) | not (isNewTyCon tc') -> rep_ty
- | otherwise -> go1 (tc:tcs) tc' tys
-
- go1 tcs tc tys = substTyWith (tyConTyVars tc) tys (go tcs tc)
+ can_unbox = case splitTyConApp_maybe arg_ty of
+ Nothing -> False
+ Just (arg_tycon, _) -> not (isRecursiveTyCon tycon) &&
+ isProductTyCon arg_tycon
\end{code}
%************************************************************************
%* *
%************************************************************************
-Dependency analysis
-~~~~~~~~~~~~~~~~~~~
+Validity checking is done once the mutually-recursive knot has been
+tied, so we can look at things freely.
+
\begin{code}
-checkLoops :: EdgeMap -> SCC RenamedTyClDecl
- -> TcM (Name -> AlgTyConFlavour -> RecFlag)
--- Check for illegal loops in a single strongly-connected component
--- a) type synonyms
--- b) superclass hierarchy
---
--- Also return a function that says which tycons are recursive.
--- Remember:
--- a newtype is recursive if it is part of a recursive
--- group consisting only of newtype and synonyms
-
-checkLoops edge_map (AcyclicSCC _)
- = returnM (\ _ _ -> NonRecursive)
-
-checkLoops edge_map (CyclicSCC decls)
- = let -- CHECK FOR CLASS CYCLES
- cls_edges = mapMaybe mkClassEdges decls
- cls_cycles = findCycles cls_edges
- in
- mapM_ (cycleErr "class") cls_cycles `thenM_`
-
- let -- CHECK FOR SYNONYM CYCLES
- syn_edges = mkEdges edge_map (filter isSynDecl decls)
- syn_cycles = findCycles syn_edges
- in
- mapM_ (cycleErr "type synonym") syn_cycles `thenM_`
-
- let -- CHECK FOR NEWTYPE CYCLES
- newtype_edges = mkEdges edge_map (filter is_nt_cycle_decl decls)
- newtype_cycles = findCycles newtype_edges
- rec_newtypes = mkNameSet [tcdName d | ds <- newtype_cycles, d <- ds]
-
- rec_tycon name (NewTyCon _)
- | name `elemNameSet` rec_newtypes = Recursive
- | otherwise = NonRecursive
- rec_tycon name other_flavour = Recursive
- in
- returnM rec_tycon
-
-----------------------------------------------------
--- A class with one op and no superclasses, or vice versa,
--- is treated just like a newtype.
--- It's a bit unclean that this test is repeated in buildTyConOrClass
-is_nt_cycle_decl (TySynonym {}) = True
-is_nt_cycle_decl (TyData {tcdND = NewType}) = True
-is_nt_cycle_decl (ClassDecl {tcdCtxt = ctxt, tcdSigs = sigs}) = length ctxt + length sigs == 1
-is_nt_cycle_decl other = False
-
-----------------------------------------------------
-findCycles edges = [ ds | CyclicSCC ds <- stronglyConnComp edges]
-
-----------------------------------------------------
--- Building edges for SCC analysis
---
--- When building the edges, we treat the 'main name' of the declaration as the
--- key for the node, but when dealing with External Core we may come across
--- references to one of the implicit names for the declaration. For example:
--- class Eq a where ....
--- data :TSig a = :TSig (:TEq a) ....
--- The first decl is sucked in from an interface file; the second
--- is in an External Core file, generated from a class decl for Sig.
--- We have to recognise that the reference to :TEq represents a
--- dependency on the class Eq declaration, else the SCC stuff won't work right.
---
--- This complication can only happen when consuming an External Core file
---
--- Solution: keep an "EdgeMap" (bad name) that maps :TEq -> Eq.
--- Don't worry about data constructors, because we're only building
--- SCCs for type and class declarations here. So the tiresome mapping
--- is need only to map [class tycon -> class]
-
-type EdgeMap = NameEnv Name
-
-mkEdgeMap :: [RenamedTyClDecl] -> TcM EdgeMap
-mkEdgeMap decls = do { mb_pairs <- mapM mk_mb_pair decls ;
- return (mkNameEnv (catMaybes mb_pairs)) }
- where
- mk_mb_pair (ClassDecl { tcdName = cls_name })
- = do { tc_name <- lookupSysName cls_name mkClassTyConOcc ;
- return (Just (tc_name, cls_name)) }
- mk_mb_pair other = return Nothing
-
-mkEdges :: EdgeMap -> [RenamedTyClDecl] -> [(RenamedTyClDecl, Name, [Name])]
--- We use the EdgeMap to map any implicit names to
--- the 'main name' for the declaration
-mkEdges edge_map decls
- = [ (decl, tyClDeclName decl, get_refs decl) | decl <- decls ]
+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_refs decl = [ lookupNameEnv edge_map n `orElse` n
- | n <- nameSetToList (tyClDeclFVs decl) ]
+ (syn_cycles, cls_cycles) = calcCycleErrs tyclss
-----------------------------------------------------
--- mk_cls_edges looks only at the context of class decls
--- Its used when we are figuring out if there's a cycle in the
--- superclass hierarchy
+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_`
-mkClassEdges :: RenamedTyClDecl -> Maybe (RenamedTyClDecl, Name, [Name])
-mkClassEdges decl@(ClassDecl {tcdCtxt = ctxt, tcdName = name}) = Just (decl, name, [c | HsClassP c _ <- ctxt])
-mkClassEdges other_decl = Nothing
-\end{code}
+ -- Check that fields with the same name share a type
+ mappM_ check_fields groups
+
+ 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
-%************************************************************************
-%* *
-\subsection{Error management
-%* *
-%************************************************************************
+-------------------------------
+checkValidClass :: Class -> TcM ()
+checkValidClass cls
+ = do { -- CHECK ARITY 1 FOR HASKELL 1.4
+ gla_exts <- doptM Opt_GlasgowExts
-\begin{code}
-cycleErr :: String -> [RenamedTyClDecl] -> TcM ()
+ -- 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
+
+ -- Check the class operations
+ ; mappM_ check_op op_stuff
-cycleErr kind_of_decl decls
- = addErrAt loc (ppr_cycle kind_of_decl decls)
+ -- 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
- loc = tcdLoc (head decls)
+ (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
+
+
+
+---------------------------------------------------------------------
+fieldTypeMisMatch field_name
+ = sep [ptext SLIT("Different constructors give different types for field"), quotes (ppr field_name)]
-ppr_cycle kind_of_decl decls
- = hang (ptext SLIT("Cycle in") <+> text kind_of_decl <+> ptext SLIT("declarations:"))
- 4 (vcat (map pp_decl decls))
+dataConCtxt con = sep [ptext SLIT("When checking the data constructor:"),
+ nest 2 (ex_part <+> pprThetaArrow ex_theta <+> ppr con <+> arg_part)]
where
- pp_decl decl = hsep [quotes (ppr (tcdName decl)),
- ptext SLIT("at"), ppr (tcdLoc decl)]
+ (_, _, 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