\section[TcInstDecls]{Typechecking instance declarations}
\begin{code}
-module TcInstDcls (
- tcInstDecls1,
- tcInstDecls2
- ) where
+module TcInstDcls ( tcInstDecls1, tcInstDecls2 ) where
#include "HsVersions.h"
import HsSyn ( HsDecl(..), InstDecl(..),
- HsBinds(..), MonoBinds(..), GRHSsAndBinds(..),
+ HsBinds(..), MonoBinds(..),
HsExpr(..), InPat(..), HsLit(..), Sig(..),
- collectMonoBinders, andMonoBindList
+ andMonoBindList
)
import RnHsSyn ( RenamedHsBinds, RenamedInstDecl, RenamedHsDecl )
-import TcHsSyn ( TcMonoBinds, TcIdOcc(..),
- maybeBoxedPrimType, tcIdType
- )
+import TcHsSyn ( TcMonoBinds, mkHsConApp )
-import TcBinds ( tcPragmaSigs )
-import TcClassDcl ( tcMethodBind, badMethodErr )
+import TcBinds ( tcSpecSigs )
+import TcClassDcl ( tcMethodBind, checkFromThisClass )
import TcMonad
-import RnMonad ( RnNameSupply )
+import RnMonad ( RnNameSupply, Fixities )
import Inst ( Inst, InstOrigin(..),
- newDicts, LIE, emptyLIE, plusLIE, plusLIEs )
+ newDicts, newClassDicts,
+ LIE, emptyLIE, plusLIE, plusLIEs )
import TcDeriv ( tcDeriving )
-import TcEnv ( GlobalValueEnv, tcExtendGlobalValEnv, tcAddImportedIdInfo, tcInstId )
+import TcEnv ( ValueEnv, tcExtendGlobalValEnv, tcExtendTyVarEnvForMeths,
+ tcAddImportedIdInfo, tcInstId
+ )
import TcInstUtil ( InstInfo(..), classDataCon )
-import TcMonoType ( tcHsType )
+import TcMonoType ( tcHsTopType )
import TcSimplify ( tcSimplifyAndCheck )
import TcType ( TcTyVar, zonkTcTyVarBndr )
import Bag ( emptyBag, unitBag, unionBags, unionManyBags,
- foldBag, bagToList, Bag
+ foldBag, Bag
)
import CmdLineOpts ( opt_GlasgowExts, opt_AllowUndecidableInstances )
import Class ( classBigSig, Class )
-import Var ( setIdInfo, idName, Id, TyVar )
-import DataCon ( isNullaryDataCon, dataConArgTys, dataConId )
+import Var ( idName, idType, Id, TyVar )
+import DataCon ( isNullaryDataCon, splitProductType_maybe )
import Maybes ( maybeToBool, catMaybes, expectJust )
import MkId ( mkDictFunId )
-import Name ( nameOccName, isLocallyDefined, Module,
- NamedThing(..)
- )
-import PrelVals ( eRROR_ID )
+import Module ( ModuleName )
+import Name ( isLocallyDefined, NamedThing(..) )
+import NameSet ( emptyNameSet )
+import PrelInfo ( eRROR_ID )
import PprType ( pprConstraint )
import SrcLoc ( SrcLoc )
-import TyCon ( isSynTyCon, isDataTyCon, tyConDerivings )
+import TyCon ( isSynTyCon, tyConDerivings )
import Type ( Type, isUnLiftedType, mkTyVarTys,
splitSigmaTy, isTyVarTy,
splitTyConApp_maybe, splitDictTy_maybe,
- splitAlgTyConApp_maybe,
- tyVarsOfTypes, substFlexiTheta
+ getClassTys_maybe, splitAlgTyConApp_maybe,
+ classesToPreds, classesOfPreds,
+ unUsgTy, tyVarsOfTypes
)
-import VarEnv ( zipVarEnv )
+import Subst ( mkTopTyVarSubst, substClasses )
import VarSet ( mkVarSet, varSetElems )
import TysPrim ( byteArrayPrimTyCon, mutableByteArrayPrimTyCon )
-import TysWiredIn ( stringTy )
+import TysWiredIn ( stringTy, isFFIArgumentTy, isFFIResultTy )
import Unique ( Unique, cCallableClassKey, cReturnableClassKey, Uniquable(..) )
import Outputable
\end{code}
\end{enumerate}
\begin{code}
-tcInstDecls1 :: GlobalValueEnv -- Contains IdInfo for dfun ids
+tcInstDecls1 :: ValueEnv -- Contains IdInfo for dfun ids
-> [RenamedHsDecl]
- -> Module -- module name for deriving
+ -> ModuleName -- module name for deriving
+ -> Fixities
-> RnNameSupply -- for renaming derivings
-> TcM s (Bag InstInfo,
- RenamedHsBinds,
- SDoc)
+ RenamedHsBinds)
-tcInstDecls1 unf_env decls mod_name rn_name_supply
+tcInstDecls1 unf_env decls mod_name fixs rn_name_supply
= -- Do the ordinary instance declarations
- mapNF_Tc (tcInstDecl1 unf_env mod_name)
+ mapNF_Tc (tcInstDecl1 unf_env)
[inst_decl | InstD inst_decl <- decls] `thenNF_Tc` \ inst_info_bags ->
let
decl_inst_info = unionManyBags inst_info_bags
-- Handle "derived" instances; note that we only do derivings
-- for things in this module; we ignore deriving decls from
-- interfaces!
- tcDeriving mod_name rn_name_supply decl_inst_info
- `thenTc` \ (deriv_inst_info, deriv_binds, ddump_deriv) ->
+ tcDeriving mod_name fixs rn_name_supply decl_inst_info
+ `thenTc` \ (deriv_inst_info, deriv_binds) ->
let
full_inst_info = deriv_inst_info `unionBags` decl_inst_info
in
- returnTc (full_inst_info, deriv_binds, ddump_deriv)
+ returnTc (full_inst_info, deriv_binds)
-tcInstDecl1 :: GlobalValueEnv -> Module -> RenamedInstDecl -> NF_TcM s (Bag InstInfo)
+tcInstDecl1 :: ValueEnv -> RenamedInstDecl -> NF_TcM s (Bag InstInfo)
-tcInstDecl1 unf_env mod_name (InstDecl poly_ty binds uprags (Just dfun_name) src_loc)
+tcInstDecl1 unf_env (InstDecl poly_ty binds uprags dfun_name src_loc)
= -- Prime error recovery, set source location
recoverNF_Tc (returnNF_Tc emptyBag) $
tcAddSrcLoc src_loc $
-- Type-check all the stuff before the "where"
- tcHsType poly_ty `thenTc` \ poly_ty' ->
+ tcHsTopType poly_ty `thenTc` \ poly_ty' ->
let
(tyvars, theta, dict_ty) = splitSigmaTy poly_ty'
- (clas, inst_tys) = case splitDictTy_maybe dict_ty of
- Nothing -> pprPanic "tcInstDecl1" (ppr poly_ty)
- Just pair -> pair
+ constr = classesOfPreds theta
+ (clas, inst_tys) = case splitDictTy_maybe dict_ty of
+ Just ct -> ct
+ Nothing -> pprPanic "tcInstDecl1" (ppr poly_ty)
in
-- Check for respectable instance type, and context
- scrutiniseInstanceHead clas inst_tys `thenNF_Tc_`
- mapNF_Tc scrutiniseInstanceConstraint theta `thenNF_Tc_`
-
- -- Make the dfun id and constant-method ids
+ -- but only do this for non-imported instance decls.
+ -- Imported ones should have been checked already, and may indeed
+ -- contain something illegal in normal Haskell, notably
+ -- instance CCallable [Char]
+ (if isLocallyDefined dfun_name then
+ scrutiniseInstanceHead clas inst_tys `thenNF_Tc_`
+ mapNF_Tc scrutiniseInstanceConstraint constr
+ else
+ returnNF_Tc []
+ ) `thenNF_Tc_`
+
+ -- Make the dfun id
let
- dfun_id = mkDictFunId dfun_name clas tyvars inst_tys theta
+ dfun_id = mkDictFunId dfun_name clas tyvars inst_tys constr
-- Add info from interface file
final_dfun_id = tcAddImportedIdInfo unf_env dfun_id
in
- returnTc (unitBag (InstInfo clas tyvars inst_tys theta
+ returnTc (unitBag (InstInfo clas tyvars inst_tys constr
final_dfun_id
binds src_loc uprags))
\end{code}
\begin{code}
tcInstDecls2 :: Bag InstInfo
- -> NF_TcM s (LIE s, TcMonoBinds s)
+ -> NF_TcM s (LIE, TcMonoBinds)
tcInstDecls2 inst_decls
= foldBag combine tcInstDecl2 (returnNF_Tc (emptyLIE, EmptyMonoBinds)) inst_decls
First comes the easy case of a non-local instance decl.
\begin{code}
-tcInstDecl2 :: InstInfo -> NF_TcM s (LIE s, TcMonoBinds s)
+tcInstDecl2 :: InstInfo -> NF_TcM s (LIE, TcMonoBinds)
tcInstDecl2 (InstInfo clas inst_tyvars inst_tys
inst_decl_theta
origin = InstanceDeclOrigin
- (class_tyvars,
- sc_theta, sc_sel_ids,
- op_sel_ids, defm_ids) = classBigSig clas
+ (class_tyvars, sc_theta, _, op_items) = classBigSig clas
+
+ dm_ids = [dm_id | (_, dm_id, _) <- op_items]
-- Instantiate the theta found in the original instance decl
- inst_decl_theta' = substFlexiTheta (zipVarEnv inst_tyvars (mkTyVarTys inst_tyvars'))
- inst_decl_theta
+ inst_decl_theta' = substClasses (mkTopTyVarSubst inst_tyvars (mkTyVarTys inst_tyvars'))
+ inst_decl_theta
-- Instantiate the super-class context with inst_tys
- sc_theta' = substFlexiTheta (zipVarEnv class_tyvars inst_tys') sc_theta
+ sc_theta' = substClasses (mkTopTyVarSubst class_tyvars inst_tys') sc_theta
in
-- Create dictionary Ids from the specified instance contexts.
- newDicts origin sc_theta' `thenNF_Tc` \ (sc_dicts, sc_dict_ids) ->
+ newClassDicts origin sc_theta' `thenNF_Tc` \ (sc_dicts, sc_dict_ids) ->
newDicts origin dfun_theta' `thenNF_Tc` \ (dfun_arg_dicts, dfun_arg_dicts_ids) ->
- newDicts origin inst_decl_theta' `thenNF_Tc` \ (inst_decl_dicts, _) ->
- newDicts origin [(clas,inst_tys')] `thenNF_Tc` \ (this_dict, [this_dict_id]) ->
+ newClassDicts origin inst_decl_theta' `thenNF_Tc` \ (inst_decl_dicts, _) ->
+ newClassDicts origin [(clas,inst_tys')] `thenNF_Tc` \ (this_dict, [this_dict_id]) ->
-- Check that all the method bindings come from this class
- let
- check_from_this_class (bndr, loc)
- | nameOccName bndr `elem` sel_names = returnNF_Tc ()
- | otherwise = tcAddSrcLoc loc $
- addErrTc (badMethodErr bndr clas)
- sel_names = map getOccName op_sel_ids
- bndrs = bagToList (collectMonoBinders monobinds)
- in
- mapNF_Tc check_from_this_class bndrs `thenNF_Tc_`
-
- tcExtendGlobalValEnv (catMaybes defm_ids) (
+ checkFromThisClass clas op_items monobinds `thenNF_Tc_`
+ tcExtendTyVarEnvForMeths inst_tyvars inst_tyvars' (
+ tcExtendGlobalValEnv dm_ids (
-- Default-method Ids may be mentioned in synthesised RHSs
- mapAndUnzip3Tc (tcMethodBind clas origin inst_tys' inst_tyvars' monobinds uprags True)
- (op_sel_ids `zip` defm_ids)
- ) `thenTc` \ (method_binds_s, insts_needed_s, meth_lies_w_ids) ->
- -- Deal with SPECIALISE instance pragmas
+ mapAndUnzip3Tc (tcMethodBind clas origin inst_tyvars' inst_tys'
+ (classesToPreds inst_decl_theta')
+ monobinds uprags True)
+ op_items
+ )) `thenTc` \ (method_binds_s, insts_needed_s, meth_lies_w_ids) ->
+
+ -- Deal with SPECIALISE instance pragmas by making them
+ -- look like SPECIALISE pragmas for the dfun
let
- dfun_prags = [Sig (idName dfun_id) ty loc | SpecInstSig ty loc <- uprags]
+ dfun_prags = [SpecSig (idName dfun_id) ty loc | SpecInstSig ty loc <- uprags]
in
tcExtendGlobalValEnv [dfun_id] (
- tcPragmaSigs dfun_prags
- ) `thenTc` \ (prag_info_fn, prag_binds, prag_lie) ->
+ tcSpecSigs dfun_prags
+ ) `thenTc` \ (prag_binds, prag_lie) ->
-- Check the overloading constraints of the methods and superclasses
dict_rhs
| null scs_and_meths
- = -- Blatant special case for CCallable, CReturnable [and Eval -- sof 5/98]
+ = -- Blatant special case for CCallable, CReturnable
-- If the dictionary is empty then we should never
-- select anything from it, so we make its RHS just
-- emit an error message. This in turn means that we don't
-- mention the constructor, which doesn't exist for CCallable, CReturnable
-- Hardly beautiful, but only three extra lines.
- HsApp (TyApp (HsVar (RealId eRROR_ID)) [tcIdType this_dict_id])
+ HsApp (TyApp (HsVar eRROR_ID) [(unUsgTy . idType) this_dict_id])
(HsLitOut (HsString msg) stringTy)
| otherwise -- The common case
- = foldl HsApp (TyApp (HsVar (RealId (dataConId dict_constr))) inst_tys')
- (map HsVar (sc_dict_ids ++ meth_ids))
+ = mkHsConApp dict_constr inst_tys' (map HsVar (sc_dict_ids ++ meth_ids))
-- We don't produce a binding for the dict_constr; instead we
-- rely on the simplifier to unfold this saturated application
-- We do this rather than generate an HsCon directly, because
-- it means that the special cases (e.g. dictionary with only one
- -- member) are dealt with by the common MkId.mkDataConId code rather
+ -- member) are dealt with by the common MkId.mkDataConWrapId code rather
-- than needing to be repeated here.
where
dict_bind = VarMonoBind this_dict_id dict_rhs
method_binds = andMonoBindList method_binds_s
- final_dfun_id = setIdInfo dfun_id (prag_info_fn (idName dfun_id))
- -- Pretty truesome
main_bind
= AbsBinds
zonked_inst_tyvars
dfun_arg_dicts_ids
- [(inst_tyvars', RealId final_dfun_id, this_dict_id)]
+ [(inst_tyvars', dfun_id, this_dict_id)]
+ emptyNameSet -- No inlines (yet)
(lie_binds1 `AndMonoBinds`
lie_binds2 `AndMonoBinds`
method_binds `AndMonoBinds`
| otherwise = addErrTc (instConstraintErr clas tys)
scrutiniseInstanceHead clas inst_taus
- | -- CCALL CHECK (a).... urgh!
- -- To verify that a user declaration of a CCallable/CReturnable
- -- instance is OK, we must be able to see the constructor(s)
- -- of the instance type (see next guard.)
- --
- -- We flag this separately to give a more precise error msg.
- --
- (getUnique clas == cCallableClassKey || getUnique clas == cReturnableClassKey)
- && is_alg_tycon_app && not constructors_visible
- = addErrTc (invisibleDataConPrimCCallErr clas first_inst_tau)
-
- | -- CCALL CHECK (b)
+ | -- CCALL CHECK
-- A user declaration of a CCallable/CReturnable instance
-- must be for a "boxed primitive" type.
(getUnique clas == cCallableClassKey && not (ccallable_type first_inst_tau)) ||
constructors_visible = not (null data_cons)
-
--- These conditions come directly from what the DsCCall is capable of.
--- Totally grotesque. Green card should solve this.
-
-ccallable_type ty = isUnLiftedType ty || -- Allow CCallable Int# etc
- maybeToBool (maybeBoxedPrimType ty) || -- Ditto Int etc
- ty == stringTy ||
- byte_arr_thing
- where
- byte_arr_thing = case splitAlgTyConApp_maybe ty of
- Just (tycon, ty_args, [data_con]) | isDataTyCon tycon ->
- length data_con_arg_tys == 2 &&
- maybeToBool maybe_arg2_tycon &&
- (arg2_tycon == byteArrayPrimTyCon ||
- arg2_tycon == mutableByteArrayPrimTyCon)
- where
- data_con_arg_tys = dataConArgTys data_con ty_args
- (data_con_arg_ty1 : data_con_arg_ty2 : _) = data_con_arg_tys
- maybe_arg2_tycon = splitTyConApp_maybe data_con_arg_ty2
- Just (arg2_tycon,_) = maybe_arg2_tycon
-
- other -> False
-
-creturnable_type ty = maybeToBool (maybeBoxedPrimType ty) ||
- -- Or, a data type with a single nullary constructor
- case (splitAlgTyConApp_maybe ty) of
- Just (tycon, tys_applied, [data_con])
- -> isNullaryDataCon data_con
- other -> False
+ccallable_type ty = isFFIArgumentTy False {- Not safe call -} ty
+creturnable_type ty = isFFIResultTy ty
\end{code}
\begin{code}
instConstraintErr clas tys
- = hang (ptext SLIT("Illegal constaint") <+>
+ = hang (ptext SLIT("Illegal constraint") <+>
quotes (pprConstraint clas tys) <+>
ptext SLIT("in instance context"))
4 (ptext SLIT("(Instance contexts must constrain only type variables)"))
4 (hsep [ ptext SLIT("class"), ppr clas, ptext SLIT("type"),
ppr inst_ty])
-{-
- Declaring CCallable & CReturnable instances in a module different
- from where the type was defined. Caused by importing data type
- abstractly (either programmatically or by the renamer being over-eager
- in its pruning.)
--}
-invisibleDataConPrimCCallErr clas inst_ty
- = hang (hsep [ptext SLIT("Constructors for"), quotes (ppr inst_ty),
- ptext SLIT("not visible when checking"),
- quotes (ppr clas), ptext SLIT("instance")])
- 4 (hsep [text "(Try either importing", ppr inst_ty,
- text "non-abstractly or compile using -fno-prune-tydecls ..)"])
-
methodCtxt = ptext SLIT("When checking the methods of an instance declaration")
superClassCtxt = ptext SLIT("When checking the superclasses of an instance declaration")
\end{code}
projects / ghc-hetmet.git / blobdiff