#include "HsVersions.h"
-import HsSyn ( HsDecl(..), TyClDecl(..),
- HsType(..), HsTyVar,
- ConDecl(..), ConDetails(..), BangType(..),
- Sig(..),
- tyClDeclName, isClassDecl, isSynDecl
+import HsSyn ( TyClDecl(..), HsConDetails(..), HsTyVarBndr(..),
+ ConDecl(..), Sig(..), , NewOrData(..),
+ tyClDeclTyVars, isSynDecl, LConDecl,
+ LTyClDecl, tcdName, LHsTyVarBndr, LHsContext
)
-import RnHsSyn ( RenamedHsDecl, RenamedTyClDecl, listTyCon_name, tupleTyCon_name )
-import BasicTypes ( RecFlag(..), NewOrData(..), Arity )
-
-import TcMonad
-import Inst ( InstanceMapper )
-import TcClassDcl ( kcClassDecl, tcClassDecl1 )
-import TcEnv ( ValueEnv, TcTyThing(..),
- tcExtendTypeEnv, getAllEnvTyCons
- )
-import TcTyDecls ( tcTyDecl, kcTyDecl )
-import TcMonoType ( kcHsTyVar )
-import TcType ( TcKind, newKindVar, newKindVars, kindToTcKind, zonkTcKindToKind )
-
-import Type ( mkArrowKind, boxedTypeKind, mkDictTy )
- -- next two imports for usage stuff only
-import TyCon ( ArgVrcs, tyConKind, tyConArity, tyConDataCons, tyConTyVars,
- tyConArgVrcs_maybe, getSynTyConDefn, isSynTyCon, isAlgTyCon )
-import DataCon ( dataConRawArgTys, dataConSig )
-
-import Class ( Class, classBigSig )
-import Type ( Type(..), TyNote(..), tyVarsOfTypes )
-import Var ( TyVar, tyVarKind )
-import FiniteMap
-import Bag
-import VarSet
-import Digraph ( stronglyConnComp, SCC(..) )
-import Name ( Name, NamedThing(..), 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 Maybes ( mapMaybe, expectJust )
-import UniqSet ( UniqSet, emptyUniqSet,
- unitUniqSet, unionUniqSets,
- unionManyUniqSets, uniqSetToList )
-import ErrUtils ( Message )
-import SrcLoc ( SrcLoc )
-import TyCon ( TyCon )
-import Unique ( Unique, Uniquable(..) )
-import UniqFM ( listToUFM, lookupUFM )
+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}
-tcTyAndClassDecls :: ValueEnv -> InstanceMapper -- Knot tying stuff
- -> [RenamedHsDecl]
- -> TcM s TcEnv
-
-tcTyAndClassDecls unf_env inst_mapper decls
- = sortByDependency decls `thenTc` \ groups ->
- tcGroups unf_env inst_mapper groups
-
-tcGroups unf_env inst_mapper []
- = tcGetEnv `thenNF_Tc` \ env ->
- returnTc env
-
-tcGroups unf_env inst_mapper (group:groups)
- = tcGroup unf_env inst_mapper group `thenTc` \ env ->
- tcSetEnv env $
- tcGroups unf_env inst_mapper groups
-\end{code}
+
+%************************************************************************
+%* *
+\subsection{Type checking for type and class declarations}
+%* *
+%************************************************************************
Dealing with a group
~~~~~~~~~~~~~~~~~~~~
-
-The knot-tying parameters: @rec_tyclss@ is an alist mapping @Name@s to
-@TcTyThing@s. @rec_vrcs@ is a finite map from @Name@s to @ArgVrcs@s.
-
-\begin{code}
-tcGroup :: ValueEnv -> InstanceMapper -> SCC RenamedTyClDecl -> TcM s TcEnv
-tcGroup unf_env inst_mapper scc
- = -- Do kind checking
- mapNF_Tc getTyBinding1 decls `thenNF_Tc` \ ty_env_stuff1 ->
- tcExtendTypeEnv ty_env_stuff1 (mapTc kcDecl decls) `thenTc_`
-
- -- Tie the knot
--- traceTc (ppr (map fst ty_env_stuff1)) `thenTc_`
- fixTc ( \ ~(rec_tyclss, rec_vrcs, _) ->
- let
- rec_env = listToUFM rec_tyclss
- in
+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.
- -- Do type checking
- mapNF_Tc (getTyBinding2 rec_env) ty_env_stuff1 `thenNF_Tc` \ ty_env_stuff2 ->
- tcExtendTypeEnv ty_env_stuff2 $
- mapTc (tcDecl is_rec_group unf_env inst_mapper rec_vrcs) decls
- `thenTc` \ tyclss ->
-
- tcGetEnv `thenTc` \ env ->
- let
- tycons = getAllEnvTyCons env
- vrcs = calcTyConArgVrcs tycons
- in
-
- returnTc (tyclss, vrcs, env)
- ) `thenTc` \ (_, _, env) ->
--- traceTc (text "done" <+> ppr (map fst ty_env_stuff1)) `thenTc_`
- returnTc env
- where
- is_rec_group = case scc of
- AcyclicSCC _ -> NonRecursive
- CyclicSCC _ -> Recursive
- decls = case scc of
- AcyclicSCC decl -> [decl]
- CyclicSCC decls -> decls
-\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}
-kcDecl decl
- = tcAddDeclCtxt decl $
- if isClassDecl decl then
- kcClassDecl decl
- else
- kcTyDecl decl
+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 :: RecFlag -- True => recursive group
- -> ValueEnv -> InstanceMapper -> FiniteMap Name ArgVrcs
- -> RenamedTyClDecl -> TcM s (Name, TcTyThing)
-tcDecl is_rec_group unf_env inst_mapper vrcs_env decl
- = tcAddDeclCtxt decl $
--- traceTc (text "Starting" <+> ppr name) `thenTc_`
- if isClassDecl decl then
- tcClassDecl1 unf_env inst_mapper vrcs_env decl `thenTc` \ clas ->
--- traceTc (text "Finished" <+> ppr name) `thenTc_`
- returnTc (getName clas, AClass clas)
- else
- tcTyDecl is_rec_group vrcs_env decl `thenTc` \ tycon ->
--- traceTc (text "Finished" <+> ppr name) `thenTc_`
- returnTc (getName tycon, ATyCon tycon)
+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 :: [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
- name = tyClDeclName decl
-
-
-tcAddDeclCtxt decl thing_inside
- = tcAddSrcLoc loc $
- tcAddErrCtxt ctxt $
- thing_inside
- where
- (name, loc, thing)
- = case decl of
- (ClassDecl _ name _ _ _ _ _ _ loc) -> (name, loc, "class")
- (TySynonym name _ _ loc) -> (name, loc, "type synonym")
- (TyData NewType _ name _ _ _ _ loc) -> (name, loc, "data type")
- (TyData DataType _ name _ _ _ _ loc) -> (name, loc, "newtype")
-
- ctxt = hsep [ptext SLIT("In the"), text thing,
- ptext SLIT("declaration for"), quotes (ppr name)]
+ mk_thing (L _ (ClassDecl {tcdLName = L _ name}), ~(AClass cl))
+ = (name, AClass cl)
+ mk_thing (L _ decl, ~(ATyCon tc))
+ = (tcdName decl, ATyCon tc)
\end{code}
-getTyBinders
-~~~~~~~~~~~
-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.
- *and* the existentially quantified contexts in datacon decls
-
-Why do we need to grab all these type variables at once, including
-those locally-quantified type variables in class op signatures?
-
- [Incidentally, this only works because the names are all unique by now.]
+%************************************************************************
+%* *
+ Kind checking
+%* *
+%************************************************************************
-Because we can only commit to the final kind of a type variable when
-we've completed the mutually recursive group. For example:
+We need to kind check all types in the mutually recursive group
+before we know the kind of the type variables. For example:
class C a where
op :: D b => a -> b -> 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.
+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.
\begin{code}
-getTyBinding1 :: RenamedTyClDecl -> NF_TcM s (Name, (TcKind, Maybe Arity, TcTyThing))
-getTyBinding1 (TySynonym name tyvars _ _)
- = mapNF_Tc kcHsTyVar tyvars `thenNF_Tc` \ arg_kinds ->
- newKindVar `thenNF_Tc` \ result_kind ->
- returnNF_Tc (name, (foldr mkArrowKind result_kind arg_kinds,
- Just (length tyvars),
- ATyCon (pprPanic "ATyCon: syn" (ppr name))))
-
-getTyBinding1 (TyData _ _ name tyvars _ _ _ _)
- = mapNF_Tc kcHsTyVar tyvars `thenNF_Tc` \ arg_kinds ->
- returnNF_Tc (name, (foldr mkArrowKind boxedTypeKind arg_kinds,
- Nothing,
- ATyCon (error "ATyCon: data")))
-
-getTyBinding1 (ClassDecl _ name tyvars _ _ _ _ _ _)
- = mapNF_Tc kcHsTyVar tyvars `thenNF_Tc` \ arg_kinds ->
- returnNF_Tc (name, (foldr mkArrowKind boxedTypeKind arg_kinds,
- Just (length tyvars),
- AClass (error "AClass")))
-
--- Zonk the kind to its final form, and lookup the
--- recursive tycon/class
-getTyBinding2 rec_env (name, (tc_kind, maybe_arity, thing))
- = zonkTcKindToKind tc_kind `thenNF_Tc` \ kind ->
- returnNF_Tc (name, (kind, maybe_arity, mk_thing thing (lookupUFM rec_env name)))
+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
- mk_thing (ATyCon _) ~(Just (ATyCon tc)) = ATyCon tc
- mk_thing (AClass _) ~(Just (AClass cls)) = AClass cls
+ 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 { ... }
+
+kindedTyVarKind (L _ (KindedTyVar _ k)) = k
\end{code}
%************************************************************************
%* *
-\subsection{Dependency analysis}
+\subsection{Type checking}
%* *
%************************************************************************
-Dependency analysis
-~~~~~~~~~~~~~~~~~~~
\begin{code}
-sortByDependency :: [RenamedHsDecl] -> TcM s [SCC RenamedTyClDecl]
-sortByDependency decls
- = let -- CHECK FOR CLASS CYCLES
- cls_sccs = stronglyConnComp (mapMaybe mk_cls_edges tycl_decls)
- cls_cycles = [ decls | CyclicSCC decls <- cls_sccs]
- in
- checkTc (null cls_cycles) (classCycleErr cls_cycles) `thenTc_`
-
- 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_`
-
- -- DO THE MAIN DEPENDENCY ANALYSIS
- let
- decl_sccs = stronglyConnComp edges
- in
- returnTc decl_sccs
+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
- tycl_decls = [d | TyClD d <- decls]
- edges = map mk_edges tycl_decls
-
- is_syn_decl (d, _, _) = isSynDecl d
- is_cls_decl (d, _, _) = isClassDecl d
+ 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}
-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_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
-
-mk_cls_edges :: RenamedTyClDecl -> Maybe (RenamedTyClDecl, Unique, [Unique])
-
-mk_cls_edges decl@(ClassDecl ctxt name _ _ _ _ _ _ _)
- = Just (decl, getUnique name, map (getUnique . fst) ctxt)
-mk_cls_edges other_decl
- = Nothing
-
-----------------------------------------------------
-mk_edges :: RenamedTyClDecl -> (RenamedTyClDecl, Unique, [Unique])
-
-mk_edges decl@(TyData _ ctxt name _ condecls derivs _ _)
- = (decl, getUnique name, uniqSetToList (get_ctxt ctxt `unionUniqSets`
- get_cons condecls `unionUniqSets`
- get_deriv derivs))
-
-mk_edges decl@(TySynonym name _ rhs _)
- = (decl, getUnique name, uniqSetToList (get_ty rhs))
-
-mk_edges decl@(ClassDecl ctxt name _ sigs _ _ _ _ _)
- = (decl, getUnique name, uniqSetToList (get_ctxt ctxt `unionUniqSets`
- get_sigs sigs))
-
-
-----------------------------------------------------
-get_ctxt ctxt = unionManyUniqSets (map (set_name.fst) ctxt)
-
-----------------------------------------------------
-get_deriv Nothing = emptyUniqSet
-get_deriv (Just clss) = unionManyUniqSets (map set_name clss)
-
-----------------------------------------------------
-get_cons cons = unionManyUniqSets (map get_con cons)
-
-----------------------------------------------------
-get_con (ConDecl _ _ ctxt details _)
- = get_ctxt ctxt `unionUniqSets` get_con_details details
-
-----------------------------------------------------
-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)
-
-----------------------------------------------------
-get_bty (Banged ty) = get_ty ty
-get_bty (Unbanged ty) = get_ty ty
-get_bty (Unpacked 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 ty)
- = set_name listTyCon_name `unionUniqSets` get_ty ty
-get_ty (MonoTupleTy tys boxed)
- = set_name (tupleTyCon_name boxed (length tys)) `unionUniqSets` get_tys tys
-get_ty (MonoUsgTy _ ty)
- = get_ty ty
-get_ty (HsForAllTy _ ctxt mty)
- = get_ctxt ctxt `unionUniqSets` get_ty mty
-get_ty (MonoDictTy name _)
- = set_name name
-
-----------------------------------------------------
-get_tys tys
- = unionManyUniqSets (map get_ty tys)
-
-----------------------------------------------------
-get_sigs sigs
- = unionManyUniqSets (mapMaybe get_sig sigs)
- where
- get_sig (ClassOpSig _ _ ty _) = Just (get_ty ty)
- get_sig (FixSig _) = Nothing
- get_sig other = panic "TcTyClsDecls:get_sig"
-
-----------------------------------------------------
-set_name name = unitUniqSet (getUnique name)
-set_to_bag set = listToBag (uniqSetToList set)
-\end{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
-\begin{code}
-typeCycleErr, classCycleErr :: [[RenamedTyClDecl]] -> Message
+ 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
-typeCycleErr syn_cycles
- = vcat (map (pp_cycle "Cycle in type declarations:") syn_cycles)
-classCycleErr cls_cycles
- = vcat (map (pp_cycle "Cycle in class declarations:") cls_cycles)
+-------------------------------
+checkValidClass :: Class -> TcM ()
+checkValidClass cls
+ = do { -- CHECK ARITY 1 FOR HASKELL 1.4
+ gla_exts <- doptM Opt_GlasgowExts
-pp_cycle str decls
- = hang (text str)
- 4 (vcat (map pp_decl decls))
+ -- 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
+
+ -- 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
- pp_decl decl
- = hsep [quotes (ppr name), ptext SLIT("at"), ppr (getSrcLoc name)]
- where
- name = tyClDeclName decl
-\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
-Computing the tyConArgVrcs info
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ ; checkValidType (FunSigCtxt op_name) tau
-@tyConArgVrcs@ gives a list of (occPos,occNeg) flags, one for each
-tyvar. For @AlgTyCon@s and @SynTyCon@s, this info must be precomputed
-separately. Note that this is information about occurrences of type
-variables, not usages of term variables.
+ -- Check that the type mentions at least one of
+ -- the class type variables
+ ; checkTc (any (`elemVarSet` tyVarsOfType tau) tyvars)
+ (noClassTyVarErr cls sel_id)
-The function @calcTyConArgVrcs@ must be passed a list of *algebraic or
-syntycons only* such that all tycons referred to (by mutual recursion)
-appear in the list. The fixpointing will be done on this set of
-tycons as a whole. It returns a list of @tyconVrcInfo@ data, ready to
-be (knot-tyingly?) stuck back into the appropriate fields.
+ -- 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
-\begin{code}
-calcTyConArgVrcs :: [TyCon]
- -> FiniteMap Name ArgVrcs
-
-calcTyConArgVrcs tycons
- = let oi = foldl (\fm tc -> addToFM fm tc (initial tc)) emptyFM tycons
- initial tc = if isAlgTyCon tc && null (tyConDataCons tc) then
- -- make pessimistic assumption (and warn)
- take (tyConArity tc) abstractVrcs
- else
- replicate (tyConArity tc) (False,False)
- oi'' = tcaoFix oi
- go (tc,vrcs) = (getName tc,vrcs)
- in listToFM (map go (fmToList oi''))
-
+
+
+---------------------------------------------------------------------
+fieldTypeMisMatch field_name
+ = sep [ptext SLIT("Different constructors give different types for field"), quotes (ppr field_name)]
+
+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
- tcaoFix :: FiniteMap TyCon ArgVrcs -- initial ArgVrcs per tycon
- -> FiniteMap TyCon ArgVrcs -- fixpointed ArgVrcs per tycon
-
- tcaoFix oi = let (changed,oi') = foldFM (\ tc pms
- (changed,oi')
- -> let pms' = tcaoIter oi' tc -- seq not simult
- in (changed || (pms /= pms'),
- addToFM oi' tc pms'))
- (False,oi) -- seq not simult for faster fixpting
- oi
- in if changed
- then tcaoFix oi'
- else oi'
-
- tcaoIter :: FiniteMap TyCon ArgVrcs -- reference ArgVrcs (initial)
- -> TyCon -- tycon to update
- -> ArgVrcs -- new ArgVrcs for tycon
-
- tcaoIter oi tc | isAlgTyCon tc
- = let cs = tyConDataCons tc
- vs = tyConTyVars tc
- argtys = concatMap dataConRawArgTys cs
- exdicttys = concatMap ((\ (_,_,_,exth,_,_) -> map (uncurry mkDictTy) exth)
- . dataConSig) cs
- myfao tc = lookupWithDefaultFM oi (expectJust "tcaoIter(Alg)" $
- tyConArgVrcs_maybe tc)
- tc
- -- we use the already-computed result for tycons not in this SCC
- in map (\v -> anyVrc (\ty -> vrcInTy myfao v ty) (exdicttys ++ argtys))
- vs
-
- tcaoIter oi tc | isSynTyCon tc
- = let (tyvs,ty) = getSynTyConDefn tc
- myfao tc = lookupWithDefaultFM oi (expectJust "tcaoIter(Syn)" $
- tyConArgVrcs_maybe tc)
- tc
- -- we use the already-computed result for tycons not in this SCC
- in map (\v -> vrcInTy myfao v ty) tyvs
-
-
-abstractVrcs :: ArgVrcs
--- we pull this out as a CAF so the warning only appears *once*
-abstractVrcs = trace ("WARNING: tyConArgVrc info inaccurate due to unavailable constructors.\n"
- ++ "\tUse -fno-prune-tydecls to fix.") $
- repeat (True,True)
-\end{code}
+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
+ sorted_decls = sortLocated cls_decls
+ ppr_decl (L loc decl) = ppr loc <> colon <+> ppr (decl { tcdSigs = [] })
-And a general variance-check function. We pass a function for
-determining the @ArgVrc@s of a tycon; when fixpointing this refers to
-the current value; otherwise this should be looked up from the tycon's
-own tyConArgVrcs.
+sortLocated :: [Located a] -> [Located a]
+sortLocated things = sortLe le things
+ where
+ le (L l1 _) (L l2 _) = l1 <= l2
-\begin{code}
-vrcInTy :: (TyCon -> ArgVrcs) -- function to get argVrcs of a tycon (break out of recursion)
- -> TyVar -- tyvar to check Vrcs of
- -> Type -- type to check for occ in
- -> (Bool,Bool) -- (occurs positively, occurs negatively)
-
-vrcInTy fao v (NoteTy (UsgNote _) ty) = vrcInTy fao v ty
-
-vrcInTy fao v (NoteTy (SynNote _) ty) = vrcInTy fao v ty
- -- SynTyCon doesn't neccessarily have vrcInfo at this point,
- -- so don't try and use it
-
-vrcInTy fao v (NoteTy (FTVNote ftv) ty) = if elemVarSet v ftv
- then vrcInTy fao v ty
- else (False,False)
- -- note that ftv cannot be calculated as occPos||occNeg,
- -- since if a tyvar occurs only as unused tyconarg,
- -- occPos==occNeg==False, but ftv=True
-
-vrcInTy fao v (TyVarTy v') = if v==v'
- then (True,False)
- else (False,False)
-
-vrcInTy fao v (AppTy ty1 ty2) = if vrcInTy fao v ty2 /= (False,False)
- then (True,True)
- else vrcInTy fao v ty1
- -- ty1 is probably unknown (or it would have been beta-reduced);
- -- hence if v occurs in ty2 at all then it could occur with
- -- either variance. Otherwise it occurs as it does in ty1.
-
-vrcInTy fao v (FunTy ty1 ty2) = let (p1,m1) = vrcInTy fao v ty1
- (p2,m2) = vrcInTy fao v ty2
- in (m1||p2,p1||m2)
-
-vrcInTy fao v (ForAllTy v' ty) = if v==v'
- then (False,False)
- else vrcInTy fao v ty
-
-vrcInTy fao v (TyConApp tc tys) = let pms1 = map (vrcInTy fao v) tys
- pms2 = fao tc
- in orVrcs (zipWith timesVrc pms1 pms2)
-
-orVrc :: (Bool,Bool) -> (Bool,Bool) -> (Bool,Bool)
-orVrc (p1,m1) (p2,m2) = (p1||p2,m1||m2)
-
-orVrcs :: [(Bool,Bool)] -> (Bool,Bool)
-orVrcs = foldl orVrc (False,False)
-
-anyVrc :: (a -> (Bool,Bool)) -> [a] -> (Bool,Bool)
-anyVrc p as = foldl (\pm a -> pm `orVrc` p a) (False,False) as
-
-timesVrc :: (Bool,Bool) -> (Bool,Bool) -> (Bool,Bool)
-timesVrc (p1,m1) (p2,m2) = (p1 && p2 || m1 && m2,
- p1 && m2 || m1 && p2)
-\end{code}
+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)
+badDataConTyCon data_con
+ = hang (ptext SLIT("Data constructor does not return its parent type:"))
+ 2 (ppr data_con)
+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