%
-% (c) The GRASP/AQUA Project, Glasgow University, 1992-1996
+% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
%
\section[TcInstDecls]{Typechecking instance declarations}
#include "HsVersions.h"
import HsSyn ( HsDecl(..), InstDecl(..),
- HsBinds(..), MonoBinds(..), GRHSsAndBinds(..), GRHS(..),
+ HsBinds(..), MonoBinds(..), GRHSsAndBinds(..),
HsExpr(..), InPat(..), HsLit(..), Sig(..),
- unguardedRHS,
- collectMonoBinders, andMonoBinds
+ collectMonoBinders, andMonoBindList
)
-import HsBinds ( sigsForMe )
-import RnHsSyn ( RenamedHsBinds, RenamedMonoBinds,
- RenamedInstDecl, RenamedHsExpr,
- RenamedSig, RenamedHsDecl
- )
-import TcHsSyn ( TcMonoBinds, TcIdOcc(..), TcIdBndr,
+import RnHsSyn ( RenamedHsBinds, RenamedInstDecl, RenamedHsDecl )
+import TcHsSyn ( TcMonoBinds, TcIdOcc(..),
maybeBoxedPrimType, tcIdType
)
import Inst ( Inst, InstOrigin(..),
newDicts, LIE, emptyLIE, plusLIE, plusLIEs )
import TcDeriv ( tcDeriving )
-import TcEnv ( GlobalValueEnv, tcExtendGlobalValEnv, tcAddImportedIdInfo )
-import TcInstUtil ( InstInfo(..), mkInstanceRelatedIds, classDataCon )
-import TcKind ( TcKind, unifyKind )
+import TcEnv ( GlobalValueEnv, tcExtendGlobalValEnv, tcAddImportedIdInfo, tcInstId )
+import TcInstUtil ( InstInfo(..), classDataCon )
import TcMonoType ( tcHsType )
import TcSimplify ( tcSimplifyAndCheck )
-import TcType ( TcType, TcTyVar, TcTyVarSet,
- zonkSigTyVar, tcInstSigType, tcInstTheta
- )
+import TcType ( TcTyVar, zonkTcTyVarBndr )
import Bag ( emptyBag, unitBag, unionBags, unionManyBags,
foldBag, bagToList, Bag
)
-import CmdLineOpts ( opt_GlasgowExts )
+import CmdLineOpts ( opt_GlasgowExts, opt_AllowUndecidableInstances )
import Class ( classBigSig, Class )
-import Id ( isNullaryDataCon, dataConArgTys, replaceIdInfo, idName, idType, Id )
-import Maybes ( maybeToBool, seqMaybe, catMaybes, expectJust )
-import Name ( nameOccName, mkLocalName,
- isLocallyDefined, Module,
+import Var ( setIdInfo, idName, Id, TyVar )
+import DataCon ( isNullaryDataCon, dataConArgTys, dataConId )
+import Maybes ( maybeToBool, catMaybes, expectJust )
+import MkId ( mkDictFunId )
+import Name ( nameOccName, isLocallyDefined, Module,
NamedThing(..)
)
import PrelVals ( eRROR_ID )
-import PprType ( pprParendType, pprConstraint )
-import SrcLoc ( SrcLoc, noSrcLoc )
+import PprType ( pprConstraint )
+import SrcLoc ( SrcLoc )
import TyCon ( isSynTyCon, isDataTyCon, tyConDerivings )
-import Type ( Type, ThetaType, isUnpointedType,
- splitSigmaTy, isTyVarTy, mkSigmaTy,
+import Type ( Type, isUnLiftedType, mkTyVarTys,
+ splitSigmaTy, isTyVarTy,
splitTyConApp_maybe, splitDictTy_maybe,
- splitAlgTyConApp_maybe, splitRhoTy,
- tyVarsOfTypes, mkTyVarTys,
+ splitAlgTyConApp_maybe,
+ tyVarsOfTypes, substFlexiTheta
)
-import TyVar ( zipTyVarEnv, mkTyVarSet, tyVarSetToList, TyVar )
+import VarEnv ( zipVarEnv )
+import VarSet ( mkVarSet, varSetElems )
import TysPrim ( byteArrayPrimTyCon, mutableByteArrayPrimTyCon )
import TysWiredIn ( stringTy )
import Unique ( Unique, cCallableClassKey, cReturnableClassKey, Uniquable(..) )
-- Make the dfun id and constant-method ids
let
- (dfun_id, dfun_theta) = mkInstanceRelatedIds dfun_name
- clas tyvars inst_tys theta
+ dfun_id = mkDictFunId dfun_name clas tyvars inst_tys theta
+
-- Add info from interface file
final_dfun_id = tcAddImportedIdInfo unf_env dfun_id
in
returnTc (unitBag (InstInfo clas tyvars inst_tys theta
- dfun_theta final_dfun_id
+ final_dfun_id
binds src_loc uprags))
\end{code}
tcInstDecl2 :: InstInfo -> NF_TcM s (LIE s, TcMonoBinds s)
tcInstDecl2 (InstInfo clas inst_tyvars inst_tys
- inst_decl_theta dfun_theta
+ inst_decl_theta
dfun_id monobinds
locn uprags)
| not (isLocallyDefined dfun_id)
tcAddSrcLoc locn $
-- Instantiate the instance decl with tc-style type variables
- tcInstSigType (idType dfun_id) `thenNF_Tc` \ dfun_ty' ->
+ tcInstId dfun_id `thenNF_Tc` \ (inst_tyvars', dfun_theta', dict_ty') ->
let
- (inst_tyvars',
- dfun_theta', dict_ty') = splitSigmaTy dfun_ty'
-
(clas, inst_tys') = expectJust "tcInstDecl2" (splitDictTy_maybe dict_ty')
+ origin = InstanceDeclOrigin
+
(class_tyvars,
sc_theta, sc_sel_ids,
op_sel_ids, defm_ids) = classBigSig clas
- origin = InstanceDeclOrigin
- in
-- Instantiate the theta found in the original instance decl
- tcInstTheta (zipTyVarEnv inst_tyvars (mkTyVarTys inst_tyvars'))
- inst_decl_theta `thenNF_Tc` \ inst_decl_theta' ->
-
- -- Instantiate the super-class context with the instance types
- tcInstTheta (zipTyVarEnv class_tyvars inst_tys') sc_theta `thenNF_Tc` \ sc_theta' ->
+ inst_decl_theta' = substFlexiTheta (zipVarEnv 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
+ in
-- Create dictionary Ids from the specified instance contexts.
newDicts origin sc_theta' `thenNF_Tc` \ (sc_dicts, sc_dict_ids) ->
newDicts origin dfun_theta' `thenNF_Tc` \ (dfun_arg_dicts, dfun_arg_dicts_ids) ->
) `thenTc` \ (prag_info_fn, prag_binds, prag_lie) ->
-- Check the overloading constraints of the methods and superclasses
- mapNF_Tc zonkSigTyVar inst_tyvars' `thenNF_Tc` \ zonked_inst_tyvars ->
+ -- tcMethodBind has checked that the class_tyvars havn't
+ -- been unified with each other or another type, but we must
+ -- still zonk them
+ mapNF_Tc zonkTcTyVarBndr inst_tyvars' `thenNF_Tc` \ zonked_inst_tyvars ->
let
- inst_tyvars_set = mkTyVarSet zonked_inst_tyvars
+ inst_tyvars_set = mkVarSet zonked_inst_tyvars
(meth_lies, meth_ids) = unzip meth_lies_w_ids
inst_tyvars_set -- Local tyvars
inst_decl_dicts -- The instance dictionaries available
sc_dicts -- The superclass dicationaries reqd
- ) `thenTc_`
+ ) `thenTc` \ _ ->
-- Ignore the result; we're only doing
-- this to make sure it can be done.
(HsLitOut (HsString msg) stringTy)
| otherwise -- The common case
- = foldl HsApp (TyApp (HsVar (RealId dict_constr)) inst_tys')
+ = foldl HsApp (TyApp (HsVar (RealId (dataConId 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
msg = _PK_ ("Compiler error: bad dictionary " ++ showSDoc (ppr clas))
dict_bind = VarMonoBind this_dict_id dict_rhs
- method_binds = andMonoBinds method_binds_s
+ method_binds = andMonoBindList method_binds_s
- final_dfun_id = replaceIdInfo dfun_id (prag_info_fn (idName dfun_id))
+ final_dfun_id = setIdInfo dfun_id (prag_info_fn (idName dfun_id))
-- Pretty truesome
main_bind
= AbsBinds
\begin{code}
scrutiniseInstanceConstraint (clas, tys)
- | all isTyVarTy tys = returnNF_Tc ()
- | otherwise = addErrTc (instConstraintErr clas tys)
+ | all isTyVarTy tys
+ || opt_AllowUndecidableInstances = returnNF_Tc ()
+ | otherwise = addErrTc (instConstraintErr clas tys)
scrutiniseInstanceHead clas inst_taus
| -- CCALL CHECK (a).... urgh!
--
-- We flag this separately to give a more precise error msg.
--
- (uniqueOf clas == cCallableClassKey || uniqueOf clas == cReturnableClassKey)
+ (getUnique clas == cCallableClassKey || getUnique clas == cReturnableClassKey)
&& is_alg_tycon_app && not constructors_visible
= addErrTc (invisibleDataConPrimCCallErr clas first_inst_tau)
| -- CCALL CHECK (b)
-- A user declaration of a CCallable/CReturnable instance
-- must be for a "boxed primitive" type.
- (uniqueOf clas == cCallableClassKey && not (ccallable_type first_inst_tau)) ||
- (uniqueOf clas == cReturnableClassKey && not (creturnable_type first_inst_tau))
+ (getUnique clas == cCallableClassKey && not (ccallable_type first_inst_tau)) ||
+ (getUnique clas == cReturnableClassKey && not (creturnable_type first_inst_tau))
= addErrTc (nonBoxedPrimCCallErr clas first_inst_tau)
-- DERIVING CHECK
= addErrTc (derivingWhenInstanceExistsErr clas first_inst_tau)
-- Kind check will have ensured inst_taus is of length 1
+ -- Allow anything for AllowUndecidableInstances
+ | opt_AllowUndecidableInstances
+ = returnNF_Tc ()
+
+ -- If GlasgowExts then check at least one isn't a type variable
+ | opt_GlasgowExts
+ = if all isTyVarTy inst_taus then
+ addErrTc (instTypeErr clas inst_taus (text "There must be at least one non-type-variable in the instance head"))
+ else
+ returnNF_Tc ()
+
-- WITH HASKELL 1.4, MUST HAVE C (T a b c)
- | not opt_GlasgowExts
- && not (length inst_taus == 1 &&
+ | not (length inst_taus == 1 &&
maybeToBool maybe_tycon_app && -- Yes, there's a type constuctor
not (isSynTyCon tycon) && -- ...but not a synonym
all isTyVarTy arg_tys && -- Applied to type variables
- length (tyVarSetToList (tyVarsOfTypes arg_tys)) == length arg_tys
+ length (varSetElems (tyVarsOfTypes arg_tys)) == length arg_tys
-- This last condition checks that all the type variables are distinct
)
= addErrTc (instTypeErr clas inst_taus
-- These conditions come directly from what the DsCCall is capable of.
-- Totally grotesque. Green card should solve this.
-ccallable_type ty = isUnpointedType ty || -- Allow CCallable Int# etc
+ccallable_type ty = isUnLiftedType ty || -- Allow CCallable Int# etc
maybeToBool (maybeBoxedPrimType ty) || -- Ditto Int etc
ty == stringTy ||
byte_arr_thing
projects / ghc-hetmet.git / blobdiff