%
-% (c) The AQUA Project, Glasgow University, 1996
+% (c) The AQUA Project, Glasgow University, 1996-1998
%
\section[TcTyClsDecls]{Typecheck type and class declarations}
\begin{code}
-#include "HsVersions.h"
-
module TcTyClsDecls (
- tcTyAndClassDecls1
+ tcTyAndClassDecls
) where
-IMP_Ubiq(){-uitous-}
+#include "HsVersions.h"
-import HsSyn ( HsDecl(..), TyDecl(..), ConDecl(..), ConDetails(..), BangType(..),
- ClassDecl(..), HsType(..), HsTyVar, DefaultDecl, InstDecl,
- IfaceSig, Sig(..), MonoBinds, Fake, InPat, HsBinds(..), HsExpr, NewOrData,
- hsDeclName
+import HsSyn ( HsDecl(..), TyClDecl(..),
+ HsType(..), HsTyVar,
+ ConDecl(..), ConDetails(..), BangType(..),
+ Sig(..), HsPred(..),
+ tyClDeclName, isClassDecl, isSynDecl
)
-import RnHsSyn ( RenamedTyDecl(..), RenamedClassDecl(..), SYN_IE(RenamedHsDecl)
- )
-import TcHsSyn ( SYN_IE(TcHsBinds), TcIdOcc(..) )
+import RnHsSyn ( RenamedHsDecl, RenamedTyClDecl, listTyCon_name, tupleTyCon_name )
+import BasicTypes ( RecFlag(..), NewOrData(..), Arity )
import TcMonad
-import Inst ( SYN_IE(InstanceMapper) )
-import TcClassDcl ( tcClassDecl1 )
-import TcEnv ( tcExtendTyConEnv, tcExtendClassEnv )
-import SpecEnv ( SpecEnv )
-import TcKind ( TcKind, newKindVars )
-import TcTyDecls ( tcTyDecl, mkDataBinds )
-import TcMonoType ( tcTyVarScope )
+import 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 )
+import Class ( Class )
+import Var ( TyVar, tyVarKind )
+import FiniteMap
import Bag
-import Class ( SYN_IE(Class) )
+import VarSet
import Digraph ( stronglyConnComp, SCC(..) )
-import Name ( Name, getSrcLoc, isTvOcc, nameOccName )
+import Name ( Name, NamedThing(..), getSrcLoc, isTvOcc, nameOccName )
import Outputable
-import Pretty
-import Maybes ( mapMaybe )
-import UniqSet ( SYN_IE(UniqSet), emptyUniqSet,
+import Maybes ( mapMaybe, expectJust )
+import UniqSet ( UniqSet, emptyUniqSet,
unitUniqSet, unionUniqSets,
unionManyUniqSets, uniqSetToList )
+import ErrUtils ( Message )
import SrcLoc ( SrcLoc )
-import TyCon ( TyCon, SYN_IE(Arity) )
-import Unique ( Unique )
-import UniqFM ( Uniquable(..) )
-import Util ( panic{-, pprTrace-} )
-
+import TyCon ( TyCon, ArgVrcs )
+import Variance ( calcTyConArgVrcs )
+import Unique ( Unique, Uniquable(..) )
+import UniqFM ( listToUFM, lookupUFM )
\end{code}
The main function
~~~~~~~~~~~~~~~~~
\begin{code}
-tcTyAndClassDecls1 :: InstanceMapper
- -> [RenamedHsDecl]
- -> TcM s (TcEnv s)
+tcTyAndClassDecls :: ValueEnv -> InstanceMapper -- Knot tying stuff
+ -> [RenamedHsDecl]
+ -> TcM s TcEnv
-tcTyAndClassDecls1 inst_mapper decls
+tcTyAndClassDecls unf_env inst_mapper decls
= sortByDependency decls `thenTc` \ groups ->
- tcGroups inst_mapper groups
+ tcGroups unf_env inst_mapper groups
-tcGroups inst_mapper []
+tcGroups unf_env inst_mapper []
= tcGetEnv `thenNF_Tc` \ env ->
returnTc env
-tcGroups inst_mapper (group:groups)
- = tcGroup inst_mapper group `thenTc` \ new_env ->
-
- -- Extend the environment using the new tycons and classes
- tcSetEnv new_env $
-
- -- Do the remaining groups
- tcGroups inst_mapper groups
+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}
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 :: InstanceMapper -> Bag RenamedHsDecl -> TcM s (TcEnv s)
-tcGroup inst_mapper decls
- = -- pprTrace "tcGroup: " (hsep (map (fst.fmt_decl) (bagToList decls))) $
+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
+
+ -- 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}
+
+Dealing with one decl
+~~~~~~~~~~~~~~~~~~~~~
+\begin{code}
+kcDecl decl
+ = tcAddDeclCtxt decl $
+ if isClassDecl decl then
+ kcClassDecl decl
+ else
+ kcTyDecl decl
+
+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)
+
+ 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)]
+\end{code}
- -- TIE THE KNOT
- fixTc ( \ ~(tycons,classes,_) ->
- -- EXTEND TYPE AND CLASS ENVIRONMENTS
- -- NB: it's important that the tycons and classes come back in just
- -- the same order from this fix as from get_binders, so that these
- -- extend-env things work properly. A bit UGH-ish.
- tcExtendTyConEnv tycon_names_w_arities tycons $
- tcExtendClassEnv class_names classes $
+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
- -- DEAL WITH TYPE VARIABLES
- tcTyVarScope tyvar_names ( \ tyvars ->
+Why do we need to grab all these type variables at once, including
+those locally-quantified type variables in class op signatures?
- -- 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
+ [Incidentally, this only works because the names are all unique by now.]
- -- SNAFFLE ENV TO RETURN
- tcGetEnv `thenNF_Tc` \ final_env ->
+Because we can only commit to the final kind of a type variable when
+we've completed the mutually recursive group. For example:
- returnTc (tycons, classes, final_env)
- ) `thenTc` \ (_, _, final_env) ->
+class C a where
+ op :: D b => a -> b -> b
- returnTc final_env
+class D c where
+ bop :: (Monad c) => ...
- where
- (tyvar_names, tycon_names_w_arities, class_names) = get_binders decls
+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.
- 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
- -> RenamedHsDecl
- -> TcM s (Bag TyCon, Bag Class)
+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)))
+ where
+ mk_thing (ATyCon _) ~(Just (ATyCon tc)) = ATyCon tc
+ mk_thing (AClass _) ~(Just (AClass cls)) = AClass cls
+\end{code}
-tcDecl inst_mapper (TyD decl)
- = tcTyDecl decl `thenTc` \ tycon ->
- returnTc (unitBag tycon, emptyBag)
-tcDecl inst_mapper (ClD decl)
- = tcClassDecl1 inst_mapper decl `thenTc` \ clas ->
- returnTc (emptyBag, unitBag clas)
-\end{code}
+%************************************************************************
+%* *
+\subsection{Dependency analysis}
+%* *
+%************************************************************************
Dependency analysis
~~~~~~~~~~~~~~~~~~~
\begin{code}
-sortByDependency :: [RenamedHsDecl] -> TcM s [Bag RenamedHsDecl]
+sortByDependency :: [RenamedHsDecl] -> TcM s [SCC RenamedTyClDecl]
sortByDependency decls
- = let -- CHECK FOR SYNONYM CYCLES
+ = 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_`
- let -- CHECK FOR CLASS CYCLES
- cls_sccs = stronglyConnComp (filter is_cls_decl edges)
- cls_cycles = [ decls | CyclicSCC decls <- cls_sccs]
-
- in
- checkTc (null cls_cycles) (classCycleErr cls_cycles) `thenTc_`
-
- -- DO THE MAIN DEPENDENCY ANALYSIS
+ -- DO THE MAIN DEPENDENCY ANALYSIS
let
- decl_sccs = stronglyConnComp (filter is_ty_cls_decl edges)
- scc_bags = map bag_acyclic decl_sccs
+ decl_sccs = stronglyConnComp edges
in
- returnTc (scc_bags)
-
+ returnTc decl_sccs
where
- edges = mapMaybe mk_edges decls
+ tycl_decls = [d | TyClD d <- decls]
+ edges = map mk_edges tycl_decls
-bag_acyclic (AcyclicSCC scc) = unitBag scc
-bag_acyclic (CyclicSCC sccs) = listToBag sccs
-
-is_syn_decl (TyD (TySynonym _ _ _ _), _, _) = True
-is_syn_decl _ = False
-
-is_ty_cls_decl (TyD _, _, _) = True
-is_ty_cls_decl (ClD _, _, _) = True
-is_ty_cls_decl other = False
-
-is_cls_decl (ClD _, _, _) = True
-is_cls_decl other = False
+ is_syn_decl (d, _, _) = isSynDecl d
+ is_cls_decl (d, _, _) = isClassDecl d
\end{code}
Edges in Type/Class decls
~~~~~~~~~~~~~~~~~~~~~~~~~
+
\begin{code}
-mk_edges decl@(TyD (TyData _ ctxt name _ condecls derivs _ _))
- = Just (decl, uniqueOf name, uniqSetToList (get_ctxt ctxt `unionUniqSets`
+----------------------------------------------------
+-- 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 . get_clas) 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@(TyD (TySynonym name _ rhs _))
- = Just (decl, uniqueOf name, uniqSetToList (get_ty rhs))
+mk_edges decl@(TySynonym name _ rhs _)
+ = (decl, getUnique name, uniqSetToList (get_ty rhs))
-mk_edges decl@(ClD (ClassDecl ctxt name _ sigs _ _ _))
- = Just (decl, uniqueOf name, uniqSetToList (get_ctxt ctxt `unionUniqSets`
+mk_edges decl@(ClassDecl ctxt name _ _ sigs _ _ _ _ _ _ _)
+ = (decl, getUnique name, uniqSetToList (get_ctxt ctxt `unionUniqSets`
get_sigs sigs))
-mk_edges other_decl = Nothing
-get_ctxt ctxt = unionManyUniqSets (map (set_name.fst) ctxt)
+----------------------------------------------------
+get_ctxt ctxt = unionManyUniqSets (map (set_name . get_clas) ctxt)
+get_clas (HsPClass clas _) = clas
+----------------------------------------------------
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_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 (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 tc ty)
- = set_name tc `unionUniqSets` get_ty ty
-get_ty (MonoTupleTy tc tys)
- = set_name tc `unionUniqSets` get_tys tys
+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 (MonoUsgForAllTy _ ty)
+ = get_ty ty
get_ty (HsForAllTy _ ctxt mty)
= get_ctxt ctxt `unionUniqSets` get_ty mty
-get_ty other = panic "TcTyClsDecls:get_ty"
+get_ty (MonoDictTy name _)
+ = set_name name
+----------------------------------------------------
get_tys tys
= unionManyUniqSets (map get_ty tys)
+----------------------------------------------------
get_sigs sigs
= unionManyUniqSets (map get_sig sigs)
where
- get_sig (ClassOpSig _ _ ty _) = get_ty ty
+ get_sig (ClassOpSig _ _ _ ty _) = get_ty ty
+ get_sig (FixSig _) = emptyUniqSet
get_sig other = panic "TcTyClsDecls:get_sig"
-set_name name = unitUniqSet (uniqueOf name)
-
+----------------------------------------------------
+set_name name = unitUniqSet (getUnique name)
set_to_bag set = listToBag (uniqSetToList set)
\end{code}
-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.
-
-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) => ...
-
-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.
-
-
\begin{code}
-get_binders :: Bag RenamedHsDecl
- -> ([HsTyVar Name], -- TyVars; no dups
- [(Name, Maybe Arity)], -- Tycons; no dups; arities for synonyms
- [Name]) -- Classes; no dups
+typeCycleErr, classCycleErr :: [[RenamedTyClDecl]] -> Message
-get_binders decls = (bagToList tyvars, bagToList tycons, bagToList classes)
- where
- (tyvars, tycons, classes) = foldBag union3 get_binders1
- (emptyBag,emptyBag,emptyBag)
- decls
-
- union3 (a1,a2,a3) (b1,b2,b3)
- = (a1 `unionBags` b1, a2 `unionBags` b2, a3 `unionBags` b3)
-
-get_binders1 (TyD (TyData _ _ name tyvars _ _ _ _))
- = (listToBag tyvars, unitBag (name,Nothing), emptyBag)
-get_binders1 (TyD (TySynonym name tyvars _ _))
- = (listToBag tyvars, unitBag (name, Just (length tyvars)), emptyBag)
-get_binders1 (ClD (ClassDecl _ name tyvar sigs _ _ _))
- = (unitBag tyvar `unionBags` sigs_tvs sigs,
- emptyBag, unitBag name)
-
-sigs_tvs sigs = unionManyBags (map sig_tvs sigs)
- where
- sig_tvs (ClassOpSig _ _ ty _) = pty_tvs ty
- pty_tvs (HsForAllTy tvs _ _) = listToBag tvs -- tvs doesn't include the class tyvar
- pty_tvs other = emptyBag
-\end{code}
-
-
-\begin{code}
-typeCycleErr syn_cycles sty
- = vcat (map (pp_cycle sty "Cycle in type declarations ...") syn_cycles)
+typeCycleErr syn_cycles
+ = vcat (map (pp_cycle "Cycle in type declarations:") syn_cycles)
-classCycleErr cls_cycles sty
- = vcat (map (pp_cycle sty "Cycle in class declarations ...") cls_cycles)
+classCycleErr cls_cycles
+ = vcat (map (pp_cycle "Cycle in class declarations:") cls_cycles)
-pp_cycle sty str decls
+pp_cycle str decls
= hang (text str)
4 (vcat (map pp_decl decls))
where
pp_decl decl
- = hsep [ppr sty name, ppr sty (getSrcLoc name)]
+ = hsep [quotes (ppr name), ptext SLIT("at"), ppr (getSrcLoc name)]
where
- name = hsDeclName decl
+ name = tyClDeclName decl
\end{code}
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