module TcInstDcls (
tcInstDecls1,
tcInstDecls2,
- processInstBinds
+ tcMethodBind
) where
-import Ubiq
+IMP_Ubiq()
-import HsSyn ( InstDecl(..), FixityDecl, Sig(..),
- SpecInstSig(..), HsBinds(..), Bind(..),
- MonoBinds(..), GRHSsAndBinds, Match,
+import HsSyn ( HsDecl(..), InstDecl(..), TyDecl, ClassDecl, DefaultDecl,
+ FixityDecl, IfaceSig, Sig(..),
+ SpecInstSig(..), HsBinds(..),
+ MonoBinds(..), GRHSsAndBinds(..), GRHS(..), Match,
InPat(..), OutPat(..), HsExpr(..), HsLit(..),
- Stmt, Qual, ArithSeqInfo, Fake,
- PolyType(..), MonoType )
-import RnHsSyn ( RenamedHsBinds(..), RenamedMonoBinds(..),
- RenamedInstDecl(..), RenamedFixityDecl(..),
- RenamedSig(..), RenamedSpecInstSig(..) )
-import TcHsSyn ( TcIdOcc(..), TcHsBinds(..),
- TcMonoBinds(..), TcExpr(..), tcIdType,
+ Stmt, DoOrListComp, ArithSeqInfo, Fake, Fixity,
+ HsType(..), HsTyVar,
+ SYN_IE(RecFlag), recursive, nonRecursive, collectMonoBinders,
+ andMonoBinds
+ )
+import RnHsSyn ( SYN_IE(RenamedHsBinds), SYN_IE(RenamedMonoBinds),
+ SYN_IE(RenamedInstDecl), SYN_IE(RenamedFixityDecl), SYN_IE(RenamedHsExpr),
+ SYN_IE(RenamedSig), SYN_IE(RenamedSpecInstSig), SYN_IE(RenamedHsDecl)
+ )
+import TcHsSyn ( TcIdOcc(..), SYN_IE(TcIdBndr), SYN_IE(TcHsBinds),
+ SYN_IE(TcMonoBinds), SYN_IE(TcExpr), tcIdType,
mkHsTyLam, mkHsTyApp,
mkHsDictLam, mkHsDictApp )
-
+import TcBinds ( tcBindWithSigs, TcSigInfo(..) )
import TcMonad
-import GenSpecEtc ( checkSigTyVars )
-import Inst ( Inst, InstOrigin(..), InstanceMapper(..),
- newDicts, newMethod, LIE(..), emptyLIE, plusLIE )
-import TcBinds ( tcPragmaSigs )
+import RnMonad ( SYN_IE(RnNameSupply) )
+import Inst ( Inst, InstOrigin(..), SYN_IE(InstanceMapper),
+ instToId, newDicts, newMethod, SYN_IE(LIE), emptyLIE, plusLIE )
+import TcBinds ( tcPragmaSigs, checkSigTyVars )
+import PragmaInfo ( PragmaInfo(..) )
import TcDeriv ( tcDeriving )
-import TcEnv ( tcLookupClass, tcTyVarScope, newLocalId )
+import TcEnv ( tcLookupClass, newLocalId, tcExtendGlobalTyVars, tcGetGlobalTyVars )
+import SpecEnv ( SpecEnv )
import TcGRHSs ( tcGRHSsAndBinds )
import TcInstUtil ( InstInfo(..), mkInstanceRelatedIds, buildInstanceEnvs )
import TcKind ( TcKind, unifyKind )
import TcMatches ( tcMatchesFun )
-import TcMonoType ( tcContext, tcMonoTypeKind )
-import TcSimplify ( tcSimplifyAndCheck, tcSimplifyThetas )
-import TcType ( TcType(..), TcTyVar(..),
- tcInstSigTyVars, tcInstType, tcInstTheta
+import TcMonoType ( tcTyVarScope, tcContext, tcHsTypeKind )
+import TcSimplify ( tcSimplifyAndCheck )
+import TcType ( SYN_IE(TcType), SYN_IE(TcTyVar), SYN_IE(TcTyVarSet),
+ tcInstSigTyVars, tcInstType, tcInstSigTcType,
+ tcInstTheta, tcInstTcType, tcInstSigType
)
-import Unify ( unifyTauTy )
+import Unify ( unifyTauTy, unifyTauTyLists )
import Bag ( emptyBag, unitBag, unionBags, unionManyBags,
- concatBag, foldBag, bagToList )
-import CmdLineOpts ( opt_GlasgowExts, opt_CompilingPrelude,
+ concatBag, foldBag, bagToList, listToBag,
+ Bag )
+import CmdLineOpts ( opt_GlasgowExts, opt_CompilingGhcInternals,
opt_OmitDefaultInstanceMethods,
- opt_SpecialiseOverloaded )
+ opt_SpecialiseOverloaded
+ )
import Class ( GenClass, GenClassOp,
- isCcallishClass, getClassBigSig,
- getClassOps, getClassOpLocalType )
-import CoreUtils ( escErrorMsg )
-import Id ( GenId, idType, isDefaultMethodId_maybe )
+ classBigSig, classOps, classOpLocalType,
+ classDefaultMethodId, SYN_IE(Class)
+ )
+import Id ( GenId, idType, isDefaultMethodId_maybe,
+ isNullaryDataCon, dataConArgTys, SYN_IE(Id) )
import ListSetOps ( minusList )
-import Maybes ( maybeToBool, expectJust )
-import Name ( Name, getTagFromClassOpName )
-import Outputable
-import PrelInfo ( pAT_ERROR_ID )
+import Maybes ( maybeToBool, expectJust, seqMaybe )
+import Name ( nameOccName, getOccString, occNameString, moduleString, getOccName,
+ isLocallyDefined, OccName, Name{--O only-}, SYN_IE(Module),
+ NamedThing(..)
+ )
+import PrelVals ( nO_EXPLICIT_METHOD_ERROR_ID )
import PprType ( GenType, GenTyVar, GenClass, GenClassOp, TyCon,
- pprParendGenType )
+ pprParendGenType
+ )
import PprStyle
+import Outputable
+import SrcLoc ( SrcLoc, noSrcLoc )
import Pretty
-import RnUtils ( GlobalNameMappers(..), GlobalNameMapper(..) )
-import TyCon ( derivedFor )
-import Type ( GenType(..), ThetaType(..), mkTyVarTys,
- splitSigmaTy, splitAppTy, isTyVarTy, matchTy, mkSigmaTy,
- getTyCon_maybe, maybeBoxedPrimType )
-import TyVar ( GenTyVar, mkTyVarSet )
+import TyCon ( isSynTyCon, derivedFor )
+import Type ( GenType(..), SYN_IE(ThetaType), mkTyVarTys, isPrimType,
+ splitSigmaTy, splitAppTys, isTyVarTy, matchTy, mkSigmaTy,
+ getTyCon_maybe, maybeAppTyCon, SYN_IE(Type),
+ maybeBoxedPrimType, maybeAppDataTyCon, splitRhoTy, eqTy
+ )
+import TyVar ( GenTyVar, SYN_IE(GenTyVarSet), tyVarSetToList,
+ mkTyVarSet, unionTyVarSets, SYN_IE(TyVar) )
+import TysPrim ( byteArrayPrimTyCon, mutableByteArrayPrimTyCon )
import TysWiredIn ( stringTy )
-import Unique ( Unique )
-import Util ( panic )
-
+import Unique ( Unique, cCallableClassKey, cReturnableClassKey )
+import UniqFM ( Uniquable(..) )
+import Util ( zipEqual, panic, pprPanic, pprTrace
+#if __GLASGOW_HASKELL__ < 202
+ , trace
+#endif
+ )
\end{code}
Typechecking instance declarations is done in two passes. The first
\end{enumerate}
\begin{code}
-tcInstDecls1 :: Bag RenamedInstDecl
- -> [RenamedSpecInstSig]
- -> FAST_STRING -- module name for deriving
- -> GlobalNameMappers -- renamer fns for deriving
- -> [RenamedFixityDecl] -- fixities for deriving
+tcInstDecls1 :: [RenamedHsDecl]
+ -> Module -- module name for deriving
+ -> RnNameSupply -- for renaming derivings
-> TcM s (Bag InstInfo,
RenamedHsBinds,
- PprStyle -> Pretty)
+ PprStyle -> Doc)
-tcInstDecls1 inst_decls specinst_sigs mod_name renamer_name_funs fixities
+tcInstDecls1 decls mod_name rn_name_supply
= -- Do the ordinary instance declarations
- mapBagNF_Tc (tcInstDecl1 mod_name) inst_decls
- `thenNF_Tc` \ inst_info_bags ->
+ mapNF_Tc (tcInstDecl1 mod_name)
+ [inst_decl | InstD inst_decl <- decls] `thenNF_Tc` \ inst_info_bags ->
let
- decl_inst_info = concatBag inst_info_bags
+ decl_inst_info = unionManyBags inst_info_bags
in
-- Handle "derived" instances; note that we only do derivings
-- for things in this module; we ignore deriving decls from
-- interfaces! We pass fixities, because they may be used
-- in deriving Read and Show.
- tcDeriving mod_name renamer_name_funs decl_inst_info fixities
+ tcDeriving mod_name rn_name_supply decl_inst_info
`thenTc` \ (deriv_inst_info, deriv_binds, ddump_deriv) ->
let
- inst_info = deriv_inst_info `unionBags` decl_inst_info
- in
-{- LATER
- -- Handle specialise instance pragmas
- tcSpecInstSigs inst_info specinst_sigs
- `thenTc` \ spec_inst_info ->
--}
- let
- spec_inst_info = emptyBag -- For now
-
- full_inst_info = inst_info `unionBags` spec_inst_info
+ full_inst_info = deriv_inst_info `unionBags` decl_inst_info
in
returnTc (full_inst_info, deriv_binds, ddump_deriv)
-tcInstDecl1 :: FAST_STRING -> RenamedInstDecl -> NF_TcM s (Bag InstInfo)
+tcInstDecl1 :: Module -> RenamedInstDecl -> NF_TcM s (Bag InstInfo)
-tcInstDecl1 mod_name
- (InstDecl class_name
- poly_ty@(HsForAllTy tyvar_names context inst_ty)
- binds
- from_here inst_mod uprags pragmas src_loc)
+tcInstDecl1 mod_name (InstDecl poly_ty binds uprags (Just dfun_name) src_loc)
= -- Prime error recovery, set source location
recoverNF_Tc (returnNF_Tc emptyBag) $
tcAddSrcLoc src_loc $
-- Look things up
- tcLookupClass class_name `thenNF_Tc` \ (clas_kind, clas) ->
+ tcLookupClass class_name `thenTc` \ (clas_kind, clas) ->
-- Typecheck the context and instance type
tcTyVarScope tyvar_names (\ tyvars ->
tcContext context `thenTc` \ theta ->
- tcMonoTypeKind inst_ty `thenTc` \ (tau_kind, tau) ->
+ tcHsTypeKind inst_ty `thenTc` \ (tau_kind, tau) ->
unifyKind clas_kind tau_kind `thenTc_`
returnTc (tyvars, theta, tau)
) `thenTc` \ (inst_tyvars, inst_theta, inst_tau) ->
-- Check for respectable instance type
- scrutiniseInstanceType from_here clas inst_tau
+ scrutiniseInstanceType dfun_name clas inst_tau
`thenTc` \ (inst_tycon,arg_tys) ->
- -- Deal with the case where we are deriving
- -- and importing the same instance
- if (not from_here && (clas `derivedFor` inst_tycon)
- && all isTyVarTy arg_tys)
- then
- if mod_name == inst_mod then
- -- Imported instance came from this module;
- -- discard and derive fresh instance
- returnTc emptyBag
- else
- -- Imported instance declared in another module;
- -- report duplicate instance error
- failTc (derivingWhenInstanceImportedErr inst_mod clas inst_tycon)
- else
-
-- Make the dfun id and constant-method ids
- mkInstanceRelatedIds from_here inst_mod pragmas
- clas inst_tyvars inst_tau inst_theta uprags
- `thenTc` \ (dfun_id, dfun_theta, const_meth_ids) ->
+ mkInstanceRelatedIds dfun_name
+ clas inst_tyvars inst_tau inst_theta
+ `thenNF_Tc` \ (dfun_id, dfun_theta) ->
returnTc (unitBag (InstInfo clas inst_tyvars inst_tau inst_theta
- dfun_theta dfun_id const_meth_ids
- binds from_here inst_mod src_loc uprags))
+ dfun_theta dfun_id
+ binds src_loc uprags))
+ where
+ (tyvar_names, context, dict_ty) = case poly_ty of
+ HsForAllTy tvs cxt dict_ty -> (tvs, cxt, dict_ty)
+ other -> ([], [], poly_ty)
+ (class_name, inst_ty) = case dict_ty of
+ MonoDictTy cls ty -> (cls,ty)
+ other -> pprPanic "Malformed intance decl" (ppr PprDebug poly_ty)
\end{code}
First comes the easy case of a non-local instance decl.
\begin{code}
-tcInstDecl2 :: InstInfo
- -> NF_TcM s (LIE s, TcHsBinds s)
-
-tcInstDecl2 (InstInfo _ _ _ _ _ _ _ _ False{-import-} _ _ _)
- = returnNF_Tc (emptyLIE, EmptyBinds)
+tcInstDecl2 :: InstInfo -> NF_TcM s (LIE s, TcHsBinds s)
tcInstDecl2 (InstInfo clas inst_tyvars inst_ty
inst_decl_theta dfun_theta
- dfun_id const_meth_ids monobinds
- True{-here-} inst_mod locn uprags)
+ dfun_id monobinds
+ locn uprags)
+ | not (isLocallyDefined dfun_id)
+ = returnNF_Tc (emptyLIE, EmptyBinds)
+
+{-
+ -- I deleted this "optimisation" because when importing these
+ -- instance decls the renamer would look for the dfun bindings and they weren't there.
+ -- This would be fixable, but it seems simpler just to produce a tiny void binding instead,
+ -- even though it's never used.
+
+ -- This case deals with CCallable etc, which don't need any bindings
+ | isNoDictClass clas
+ = returnNF_Tc (emptyLIE, EmptyBinds)
+-}
+
+ | otherwise
= -- Prime error recovery
recoverNF_Tc (returnNF_Tc (emptyLIE, EmptyBinds)) $
tcAddSrcLoc locn $
-- Get the class signature
tcInstSigTyVars inst_tyvars `thenNF_Tc` \ (inst_tyvars', _, tenv) ->
let
+ origin = InstanceDeclOrigin
(class_tyvar,
super_classes, sc_sel_ids,
- class_ops, op_sel_ids, defm_ids) = getClassBigSig clas
+ class_ops, op_sel_ids, defm_ids) = classBigSig clas
in
tcInstType tenv inst_ty `thenNF_Tc` \ inst_ty' ->
tcInstTheta tenv dfun_theta `thenNF_Tc` \ dfun_theta' ->
tcInstTheta tenv inst_decl_theta `thenNF_Tc` \ inst_decl_theta' ->
let
- sc_theta' = super_classes `zip` (repeat inst_ty')
- origin = InstanceDeclOrigin
- mk_method sel_id = newMethodId sel_id inst_ty' origin locn
+ sc_theta' = super_classes `zip` repeat inst_ty'
in
-- Create dictionary Ids from the specified instance contexts.
newDicts origin sc_theta' `thenNF_Tc` \ (sc_dicts, sc_dict_ids) ->
newDicts origin inst_decl_theta' `thenNF_Tc` \ (inst_decl_dicts, _) ->
newDicts origin [(clas,inst_ty')] `thenNF_Tc` \ (this_dict, [this_dict_id]) ->
- -- Create method variables
- mapAndUnzipNF_Tc mk_method op_sel_ids `thenNF_Tc` \ (meth_insts_s, meth_ids) ->
-
- -- Collect available Insts
+ -- Check the method bindings
let
- avail_insts -- These insts are in scope; quite a few, eh?
- = unionManyBags (this_dict : dfun_arg_dicts : meth_insts_s)
-
- mk_method_expr
- = if opt_OmitDefaultInstanceMethods then
- makeInstanceDeclNoDefaultExpr origin meth_ids defm_ids inst_ty' clas inst_mod
- else
- makeInstanceDeclDefaultMethodExpr origin meth_ids defm_ids inst_ty' this_dict_id
- in
- processInstBinds mk_method_expr inst_tyvars' avail_insts meth_ids monobinds
- `thenTc` \ (insts_needed, method_mbinds) ->
- let
- -- Create the dict and method binds
- dict_bind
- = VarMonoBind this_dict_id (Dictionary sc_dict_ids meth_ids)
-
- dict_and_method_binds
- = dict_bind `AndMonoBinds` method_mbinds
-
inst_tyvars_set' = mkTyVarSet inst_tyvars'
+ check_from_this_class (bndr, loc)
+ | nameOccName bndr `elem` sel_names = returnTc ()
+ | otherwise = recoverTc (returnTc ()) $
+ tcAddSrcLoc loc $
+ failTc (instBndrErr bndr clas)
+ sel_names = map getOccName op_sel_ids
in
+ mapTc check_from_this_class (bagToList (collectMonoBinders monobinds)) `thenTc_`
+ tcExtendGlobalTyVars inst_tyvars_set' (
+ mapAndUnzip3Tc (tcMethodBind (getDefmRhs clas) inst_ty' monobinds)
+ (op_sel_ids `zip` [0..])
+ ) `thenTc` \ (method_binds_s, insts_needed_s, meth_lies_w_ids) ->
+
-- Check the overloading constraints of the methods and superclasses
+ let
+ (meth_lies, meth_ids) = unzip meth_lies_w_ids
+ avail_insts -- These insts are in scope; quite a few, eh?
+ = this_dict `plusLIE` dfun_arg_dicts `plusLIE` unionManyBags meth_lies
+ in
tcAddErrCtxt (bindSigCtxt meth_ids) (
tcSimplifyAndCheck
inst_tyvars_set' -- Local tyvars
avail_insts
- (sc_dicts `unionBags` insts_needed) -- Need to get defns for all these
+ (sc_dicts `unionBags`
+ unionManyBags insts_needed_s) -- Need to get defns for all these
) `thenTc` \ (const_lie, super_binds) ->
-- Check that we *could* construct the superclass dictionaries,
-- the check ensures that the caller will never have a problem building
-- them.
tcAddErrCtxt superClassSigCtxt (
- tcSimplifyAndCheck
+ tcSimplifyAndCheck
inst_tyvars_set' -- Local tyvars
inst_decl_dicts -- The instance dictionaries available
sc_dicts -- The superclass dicationaries reqd
spec_sigs = [ s | s@(SpecSig _ _ _ _) <- uprags ]
in
tcPragmaSigs spec_sigs `thenTc` \ (_, spec_binds, spec_lie) ->
+
+ -- Create the result bindings
let
- -- Complete the binding group, adding any spec_binds
- inst_binds
- = AbsBinds
+ dict_bind = VarMonoBind this_dict_id (Dictionary sc_dict_ids meth_ids)
+ method_binds = andMonoBinds method_binds_s
+
+ main_bind
+ = MonoBind (
+ AbsBinds
inst_tyvars'
dfun_arg_dicts_ids
- ((this_dict_id, RealId dfun_id)
- : (meth_ids `zip` (map RealId const_meth_ids)))
- -- const_meth_ids will often be empty
- super_binds
- (RecBind dict_and_method_binds)
-
- `ThenBinds`
- spec_binds
+ [(inst_tyvars', RealId dfun_id, this_dict_id)]
+ (super_binds `AndMonoBinds`
+ method_binds `AndMonoBinds`
+ dict_bind))
+ [] recursive -- Recursive to play safe
in
-
- returnTc (const_lie `plusLIE` spec_lie, inst_binds)
+ returnTc (const_lie `plusLIE` spec_lie,
+ main_bind `ThenBinds` spec_binds)
\end{code}
-@mkMethodId@ manufactures an id for a local method.
-It's rather turgid stuff, because there are two cases:
-
- (a) For methods with no local polymorphism, we can make an Inst of the
- class-op selector function and a corresp InstId;
- which is good because then other methods which call
- this one will do so directly.
-
- (b) For methods with local polymorphism, we can't do this. For example,
-
- class Foo a where
- op :: (Num b) => a -> b -> a
-
- Here the type of the class-op-selector is
-
- forall a b. (Foo a, Num b) => a -> b -> a
-
- The locally defined method at (say) type Float will have type
-
- forall b. (Num b) => Float -> b -> Float
-
- and the one is not an instance of the other.
-
- So for these we just make a local (non-Inst) id with a suitable type.
-
-How disgusting.
-
-\begin{code}
-newMethodId sel_id inst_ty origin loc
- = let (sel_tyvars,sel_theta,sel_tau) = splitSigmaTy (idType sel_id)
- (_:meth_theta) = sel_theta -- The local theta is all except the
- -- first element of the context
- in
- case sel_tyvars of
- -- Ah! a selector for a class op with no local polymorphism
- -- Build an Inst for this
- [clas_tyvar] -> newMethod origin (RealId sel_id) [inst_ty]
-
- -- Ho! a selector for a class op with local polymorphism.
- -- Just make a suitably typed local id for this
- (clas_tyvar:local_tyvars) ->
- tcInstType [(clas_tyvar,inst_ty)]
- (mkSigmaTy local_tyvars meth_theta sel_tau)
- `thenNF_Tc` \ method_ty ->
- newLocalId (getOccurrenceName sel_id) method_ty `thenNF_Tc` \ meth_id ->
- returnNF_Tc (emptyLIE, meth_id)
-\end{code}
-
-The next function makes a default method which calls the global default method, at
-the appropriate instance type.
+The next function looks for a method binding; if there isn't one it
+manufactures one that just calls the global default method.
See the notes under default decls in TcClassDcl.lhs.
\begin{code}
-makeInstanceDeclDefaultMethodExpr
- :: InstOrigin s
- -> [TcIdOcc s]
- -> [Id]
- -> TcType s
- -> TcIdOcc s
- -> Int
- -> NF_TcM s (TcExpr s)
-
-makeInstanceDeclDefaultMethodExpr origin meth_ids defm_ids inst_ty this_dict tag
- = newDicts origin op_theta `thenNF_Tc` \ (op_lie,op_dicts) ->
-
- -- def_op_id = /\ op_tyvars -> \ op_dicts ->
- -- defm_id inst_ty op_tyvars this_dict op_dicts
- returnNF_Tc (
- mkHsTyLam op_tyvars (
- mkHsDictLam op_dicts (
- mkHsDictApp (mkHsTyApp (HsVar (RealId defm_id))
- (inst_ty : mkTyVarTys op_tyvars))
- (this_dict : op_dicts)
- )))
- where
- idx = tag - 1
- meth_id = meth_ids !! idx
- defm_id = defm_ids !! idx
- (op_tyvars, op_theta, op_tau) = splitSigmaTy (tcIdType meth_id)
-
-makeInstanceDeclNoDefaultExpr
- :: InstOrigin s
- -> [TcIdOcc s]
- -> [Id]
- -> TcType s
- -> Class
- -> FAST_STRING
- -> Int
- -> NF_TcM s (TcExpr s)
-
-makeInstanceDeclNoDefaultExpr origin meth_ids defm_ids inst_ty clas inst_mod tag
- = newDicts origin op_theta `thenNF_Tc` \ (op_lie, op_dicts) ->
-
- -- Produce a warning if the default instance method
- -- has been omitted when one exists in the class
- warnTc (not err_defm_ok)
- (omitDefaultMethodWarn clas_op clas_name inst_ty)
- `thenNF_Tc_`
- returnNF_Tc (mkHsTyLam op_tyvars (
- mkHsDictLam op_dicts (
- HsApp (mkHsTyApp (HsVar (RealId pAT_ERROR_ID)) [op_tau])
- (HsLitOut (HsString (_PK_ error_msg)) stringTy))))
- where
- idx = tag - 1
- meth_id = meth_ids !! idx
- clas_op = (getClassOps clas) !! idx
- defm_id = defm_ids !! idx
- (op_tyvars,op_theta,op_tau) = splitSigmaTy (tcIdType meth_id)
-
- Just (_, _, err_defm_ok) = isDefaultMethodId_maybe defm_id
-
- error_msg = "%E" -- => No explicit method for \"
- ++ escErrorMsg error_str
-
- error_str = _UNPK_ inst_mod ++ "." ++ _UNPK_ clas_name ++ "."
- ++ (ppShow 80 (ppr PprForUser inst_ty)) ++ "."
- ++ (ppShow 80 (ppr PprForUser clas_op)) ++ "\""
-
- (_, clas_name) = getOrigName clas
+getDefmRhs :: Class -> Int -> RenamedHsExpr
+getDefmRhs clas idx = HsVar (getName (classDefaultMethodId clas idx))
\end{code}
%* *
%************************************************************************
-@processInstBinds@ returns a @MonoBinds@ which binds
-all the method ids (which are passed in). It is used
- - both for instance decls,
- - and to compile the default-method declarations in a class decl.
-
-Any method ids which don't have a binding have a suitable default
-binding created for them. The actual right-hand side used is
-created using a function which is passed in, because the right thing to
-do differs between instance and class decls.
-
\begin{code}
-processInstBinds
- :: (Int -> NF_TcM s (TcExpr s)) -- Function to make default method
- -> [TcTyVar s] -- Tyvars for this instance decl
- -> LIE s -- available Insts
- -> [TcIdOcc s] -- Local method ids in tag order
- -- (instance tyvars are free in their types)
- -> RenamedMonoBinds
- -> TcM s (LIE s, -- These are required
- TcMonoBinds s)
-
-processInstBinds mk_default_method_rhs inst_tyvars avail_insts method_ids monobinds
- =
- -- Process the explicitly-given method bindings
- processInstBinds1 inst_tyvars avail_insts method_ids monobinds
- `thenTc` \ (tags, insts_needed_in_methods, method_binds) ->
-
- -- Find the methods not handled, and make default method bindings for them.
+tcMethodBind
+ :: (Int -> RenamedHsExpr) -- Function mapping a tag to default RHS
+ -> TcType s -- Instance type
+ -> RenamedMonoBinds -- Method binding
+ -> (Id, Int) -- Selector ID (and its 0-indexed tag)
+ -- for which binding is wanted
+ -> TcM s (TcMonoBinds s, LIE s, (LIE s, TcIdOcc s))
+
+tcMethodBind deflt_fn inst_ty meth_binds (sel_id, idx)
+ = newMethod origin (RealId sel_id) [inst_ty] `thenNF_Tc` \ meth@(_, TcId meth_id) ->
+ tcInstSigTcType (idType meth_id) `thenNF_Tc` \ (tyvars', rho_ty') ->
let
- unmentioned_tags = [1.. length method_ids] `minusList` tags
- in
- mapNF_Tc mk_default_method unmentioned_tags
- `thenNF_Tc` \ default_bind_list ->
-
- returnTc (insts_needed_in_methods,
- foldr AndMonoBinds method_binds default_bind_list)
- where
- -- From a tag construct us the passed-in function to construct
- -- the binding for the default method
- mk_default_method tag = mk_default_method_rhs tag `thenNF_Tc` \ rhs ->
- returnNF_Tc (VarMonoBind (method_ids !! (tag-1)) rhs)
-\end{code}
-
-\begin{code}
-processInstBinds1
- :: [TcTyVar s] -- Tyvars for this instance decl
- -> LIE s -- available Insts
- -> [TcIdOcc s] -- Local method ids in tag order (instance tyvars are free),
- -> RenamedMonoBinds
- -> TcM s ([Int], -- Class-op tags accounted for
- LIE s, -- These are required
- TcMonoBinds s)
-
-processInstBinds1 inst_tyvars avail_insts method_ids EmptyMonoBinds
- = returnTc ([], emptyLIE, EmptyMonoBinds)
-
-processInstBinds1 inst_tyvars avail_insts method_ids (AndMonoBinds mb1 mb2)
- = processInstBinds1 inst_tyvars avail_insts method_ids mb1
- `thenTc` \ (op_tags1,dicts1,method_binds1) ->
- processInstBinds1 inst_tyvars avail_insts method_ids mb2
- `thenTc` \ (op_tags2,dicts2,method_binds2) ->
- returnTc (op_tags1 ++ op_tags2,
- dicts1 `unionBags` dicts2,
- AndMonoBinds method_binds1 method_binds2)
-\end{code}
+ meth_name = getName meth_id
+ default_bind = PatMonoBind (VarPatIn meth_name)
+ (GRHSsAndBindsIn [OtherwiseGRHS (deflt_fn idx) noSrcLoc] EmptyBinds)
+ noSrcLoc
-\begin{code}
-processInstBinds1 inst_tyvars avail_insts method_ids mbind
- =
- -- Find what class op is being defined here. The complication is
- -- that we could have a PatMonoBind or a FunMonoBind. If the
- -- former, it should only bind a single variable, or else we're in
- -- trouble (I'm not sure what the static semantics of methods
- -- defined in a pattern binding with multiple patterns is!)
- -- Renamer has reduced us to these two cases.
- let
- (op,locn) = case mbind of
- FunMonoBind op _ locn -> (op, locn)
- PatMonoBind (VarPatIn op) _ locn -> (op, locn)
+ (op_name, op_bind) = case go (getOccName sel_id) meth_binds of
+ Just stuff -> stuff
+ Nothing -> (meth_name, default_bind)
- occ = getOccurrenceName op
- origin = InstanceDeclOrigin
+ (theta', tau') = splitRhoTy rho_ty'
+ sig_info = TySigInfo op_name meth_id tyvars' theta' tau' noSrcLoc
in
- tcAddSrcLoc locn $
+ tcBindWithSigs [op_name] op_bind [sig_info]
+ nonRecursive (\_ -> NoPragmaInfo) `thenTc` \ (binds, insts, _) ->
- -- Make a method id for the method
- let tag = getTagFromClassOpName op
- method_id = method_ids !! (tag-1)
+ returnTc (binds, insts, meth)
+ where
+ origin = InstanceDeclOrigin -- Poor
- TcId method_bndr = method_id
- method_ty = idType method_bndr
- (method_tyvars, method_theta, method_tau) = splitSigmaTy method_ty
- in
- newDicts origin method_theta `thenNF_Tc` \ (method_dicts,method_dict_ids) ->
-
- case (method_tyvars, method_dict_ids) of
-
- ([],[]) -> -- The simple case; no local polymorphism or overloading in the method
-
- -- Type check the method itself
- tcMethodBind method_id method_tau mbind `thenTc` \ (mbind', lieIop) ->
- returnTc ([tag], lieIop, mbind')
-
- other -> -- It's a locally-polymorphic and/or overloaded method; UGH!
-
- -- Make a new id for (a) the local, non-overloaded method
- -- and (b) the locally-overloaded method
- -- The latter is needed just so we can return an AbsBinds wrapped
- -- up inside a MonoBinds.
-
- newLocalId occ method_tau `thenNF_Tc` \ local_id ->
- newLocalId occ method_ty `thenNF_Tc` \ copy_id ->
- let
- inst_method_tyvars = inst_tyvars ++ method_tyvars
- in
- -- Typecheck the method
- tcMethodBind local_id method_tau mbind `thenTc` \ (mbind', lieIop) ->
-
- -- Check the overloading part of the signature.
- -- Simplify everything fully, even though some
- -- constraints could "really" be left to the next
- -- level out. The case which forces this is
- --
- -- class Foo a where { op :: Bar a => a -> a }
- --
- -- Here we must simplify constraints on "a" to catch all
- -- the Bar-ish things.
- tcAddErrCtxt (methodSigCtxt op method_ty) (
- tcSimplifyAndCheck
- (mkTyVarSet inst_method_tyvars)
- (method_dicts `plusLIE` avail_insts)
- lieIop
- ) `thenTc` \ (f_dicts, dict_binds) ->
-
- returnTc ([tag],
- f_dicts,
- VarMonoBind method_id
- (HsLet
- (AbsBinds
- method_tyvars
- method_dict_ids
- [(local_id, copy_id)]
- dict_binds
- (NonRecBind mbind'))
- (HsVar copy_id)))
-\end{code}
+ go occ EmptyMonoBinds = Nothing
+ go occ (AndMonoBinds b1 b2) = go occ b1 `seqMaybe` go occ b2
-\begin{code}
-tcMethodBind :: TcIdOcc s -> TcType s -> RenamedMonoBinds
- -> TcM s (TcMonoBinds s, LIE s)
-
-tcMethodBind meth_id meth_ty (FunMonoBind name matches locn)
- = tcMatchesFun name meth_ty matches `thenTc` \ (rhs', lie) ->
- returnTc (FunMonoBind meth_id rhs' locn, lie)
-
-tcMethodBind meth_id meth_ty pbind@(PatMonoBind pat grhss_and_binds locn)
- -- pat is sure to be a (VarPatIn op)
- = tcAddErrCtxt (patMonoBindsCtxt pbind) $
- tcGRHSsAndBinds grhss_and_binds `thenTc` \ (grhss_and_binds', lie, rhs_ty) ->
- unifyTauTy meth_ty rhs_ty `thenTc_`
- returnTc (PatMonoBind (VarPat meth_id) grhss_and_binds' locn, lie)
+ go occ b@(FunMonoBind op_name _ _ locn) | nameOccName op_name == occ = Just (op_name, b)
+ | otherwise = Nothing
+ go occ b@(PatMonoBind (VarPatIn op_name) _ locn) | nameOccName op_name == occ = Just (op_name, b)
+ | otherwise = Nothing
+ go occ other = panic "Urk! Bad instance method binding"
\end{code}
+
%************************************************************************
%* *
\subsection{Type-checking specialise instance pragmas}
clas = lookupCE ce class_name -- Renamer ensures this can't fail
-- Make some new type variables, named as in the specialised instance type
- ty_names = extractMonoTyNames (==) ty
+ ty_names = extractHsTyNames ???is_tyvarish_name??? ty
(tmpl_e,inst_tmpls,inst_tmpl_tys) = mkTVE ty_names
in
babyTcMtoTcM (tcInstanceType ce tce tmpl_e True src_loc ty)
copyTyVars inst_tmpls `thenNF_Tc` \ (tv_e, inst_tvs, inst_tv_tys) ->
let
Just (InstInfo _ unspec_tyvars unspec_inst_ty unspec_theta
- _ _ _ binds True{-from here-} mod _ uprag) = maybe_unspec_inst
+ _ _ binds _ uprag) = maybe_unspec_inst
subst = case matchTy unspec_inst_ty inst_ty of
Just subst -> subst
mk_spec_origin clas ty
= InstanceSpecOrigin inst_mapper clas ty src_loc
+ -- I'm VERY SUSPICIOUS ABOUT THIS
+ -- the inst-mapper is in a knot at this point so it's no good
+ -- looking at it in tcSimplify...
in
tcSimplifyThetas mk_spec_origin subst_tv_theta
`thenTc` \ simpl_tv_theta ->
let
simpl_theta = [ (clas, tv_to_tmpl tv) | (clas, tv) <- simpl_tv_theta ]
- tv_tmpl_map = inst_tv_tys `zipEqual` inst_tmpl_tys
+ tv_tmpl_map = zipEqual "tcSpecInstSig" inst_tv_tys inst_tmpl_tys
tv_to_tmpl tv = assoc "tcSpecInstSig" tv_tmpl_map tv
in
- mkInstanceRelatedIds e True{-from here-} mod NoInstancePragmas src_loc
+ mkInstanceRelatedIds
clas inst_tmpls inst_ty simpl_theta uprag
- `thenTc` \ (dfun_id, dfun_theta, const_meth_ids) ->
+ `thenNF_Tc` \ (dfun_id, dfun_theta, const_meth_ids) ->
getSwitchCheckerTc `thenNF_Tc` \ sw_chkr ->
(if sw_chkr SpecialiseTrace then
pprTrace "Specialised Instance: "
- (ppAboves [ppCat [if null simpl_theta then ppNil else ppr PprDebug simpl_theta,
- if null simpl_theta then ppNil else ppStr "=>",
+ (vcat [hsep [if null simpl_theta then empty else ppr PprDebug simpl_theta,
+ if null simpl_theta then empty else ptext SLIT("=>"),
ppr PprDebug clas,
pprParendGenType PprDebug inst_ty],
- ppCat [ppStr " derived from:",
- if null unspec_theta then ppNil else ppr PprDebug unspec_theta,
- if null unspec_theta then ppNil else ppStr "=>",
+ hsep [ptext SLIT(" derived from:"),
+ if null unspec_theta then empty else ppr PprDebug unspec_theta,
+ if null unspec_theta then empty else ptext SLIT("=>"),
ppr PprDebug clas,
pprParendGenType PprDebug unspec_inst_ty]])
else id) (
returnTc (unitBag (InstInfo clas inst_tmpls inst_ty simpl_theta
- dfun_theta dfun_id const_meth_ids
- binds True{-from here-} mod src_loc uprag))
+ dfun_theta dfun_id
+ binds src_loc uprag))
)))
We can also have instances for functions: @instance Foo (a -> b) ...@.
\begin{code}
-scrutiniseInstanceType from_here clas inst_tau
+scrutiniseInstanceType dfun_name clas inst_tau
-- TYCON CHECK
- | not (maybeToBool inst_tycon_maybe)
+ | not (maybeToBool inst_tycon_maybe) || isSynTyCon inst_tycon
= failTc (instTypeErr inst_tau)
-- IMPORTED INSTANCES ARE OK (but see tcInstDecl1)
- | from_here
+ | not (isLocallyDefined dfun_name)
= returnTc (inst_tycon,arg_tys)
-- TYVARS CHECK
| not (all isTyVarTy arg_tys ||
- not from_here ||
opt_GlasgowExts)
= failTc (instTypeErr inst_tau)
= failTc (derivingWhenInstanceExistsErr clas inst_tycon)
| -- CCALL CHECK
- -- A user declaration of a _CCallable/_CReturnable instance
+ -- A user declaration of a CCallable/CReturnable instance
-- must be for a "boxed primitive" type.
- isCcallishClass clas
- && not opt_CompilingPrelude -- which allows anything
- && maybeToBool (maybeBoxedPrimType inst_tau)
+ (uniqueOf clas == cCallableClassKey && not (ccallable_type inst_tau)) ||
+ (uniqueOf clas == cReturnableClassKey && not (creturnable_type inst_tau))
= failTc (nonBoxedPrimCCallErr clas inst_tau)
| otherwise
= returnTc (inst_tycon,arg_tys)
where
- (possible_tycon, arg_tys) = splitAppTy inst_tau
+ (possible_tycon, arg_tys) = splitAppTys inst_tau
inst_tycon_maybe = getTyCon_maybe possible_tycon
inst_tycon = expectJust "tcInstDecls1:inst_tycon" inst_tycon_maybe
+
+-- These conditions come directly from what the DsCCall is capable of.
+-- Totally grotesque. Green card should solve this.
+
+ccallable_type ty = isPrimType ty || -- Allow CCallable Int# etc
+ maybeToBool (maybeBoxedPrimType ty) || -- Ditto Int etc
+ ty `eqTy` stringTy ||
+ byte_arr_thing
+ where
+ byte_arr_thing = case maybeAppDataTyCon ty of
+ Just (tycon, ty_args, [data_con]) ->
+-- pprTrace "cc1" (sep [ppr PprDebug tycon, ppr PprDebug data_con,
+-- sep (map (ppr PprDebug) data_con_arg_tys)])(
+ length data_con_arg_tys == 2 &&
+ maybeToBool maybe_arg2_tycon &&
+-- pprTrace "cc2" (sep [ppr PprDebug 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 = maybeAppTyCon 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 (maybeAppDataTyCon ty) of
+ Just (tycon, tys_applied, [data_con])
+ -> isNullaryDataCon data_con
+ other -> False
\end{code}
\begin{code}
instTypeErr ty sty
= case ty of
- SynTy tc _ _ -> ppBesides [ppStr "The type synonym `", ppr sty tc, rest_of_msg]
- TyVarTy tv -> ppBesides [ppStr "The type variable `", ppr sty tv, rest_of_msg]
- other -> ppBesides [ppStr "The type `", ppr sty ty, rest_of_msg]
+ SynTy tc _ _ -> hcat [ptext SLIT("The type synonym `"), ppr sty tc, rest_of_msg]
+ TyVarTy tv -> hcat [ptext SLIT("The type variable `"), ppr sty tv, rest_of_msg]
+ other -> hcat [ptext SLIT("The type `"), ppr sty ty, rest_of_msg]
where
- rest_of_msg = ppStr "' cannot be used as an instance type."
+ rest_of_msg = ptext SLIT("' cannot be used as an instance type.")
+
+instBndrErr bndr clas sty
+ = hsep [ptext SLIT("Class"), ppr sty clas, ptext SLIT("does not have a method"), ppr sty bndr]
derivingWhenInstanceExistsErr clas tycon sty
- = ppHang (ppBesides [ppStr "Deriving class `", ppr sty clas, ppStr "' type `", ppr sty tycon, ppStr "'"])
- 4 (ppStr "when an explicit instance exists")
+ = hang (hsep [ptext SLIT("Deriving class"),
+ ppr sty clas,
+ ptext SLIT("type"), ppr sty tycon])
+ 4 (ptext SLIT("when an explicit instance exists"))
derivingWhenInstanceImportedErr inst_mod clas tycon sty
- = ppHang (ppBesides [ppStr "Deriving class `", ppr sty clas, ppStr "' type `", ppr sty tycon, ppStr "'"])
- 4 (ppBesides [ppStr "when an instance declared in module `", ppPStr inst_mod, ppStr "' has been imported"])
+ = hang (hsep [ptext SLIT("Deriving class"),
+ ppr sty clas,
+ ptext SLIT("type"), ppr sty tycon])
+ 4 (hsep [ptext SLIT("when an instance declared in module"),
+ pp_mod, ptext SLIT("has been imported")])
+ where
+ pp_mod = hsep [ptext SLIT("module"), ptext inst_mod]
nonBoxedPrimCCallErr clas inst_ty sty
- = ppHang (ppStr "Instance isn't for a `boxed-primitive' type")
- 4 (ppBesides [ ppStr "class `", ppr sty clas, ppStr "' type `",
- ppr sty inst_ty, ppStr "'"])
+ = hang (ptext SLIT("Unacceptable instance type for ccall-ish class"))
+ 4 (hsep [ ptext SLIT("class"), ppr sty clas, ptext SLIT("type"),
+ ppr sty inst_ty])
omitDefaultMethodWarn clas_op clas_name inst_ty sty
- = ppCat [ppStr "Warning: Omitted default method for",
- ppr sty clas_op, ppStr "in instance",
- ppPStr clas_name, pprParendGenType sty inst_ty]
+ = hsep [ptext SLIT("Warning: Omitted default method for"),
+ ppr sty clas_op, ptext SLIT("in instance"),
+ text clas_name, pprParendGenType sty inst_ty]
+instMethodNotInClassErr occ clas sty
+ = hang (ptext SLIT("Instance mentions a method not in the class"))
+ 4 (hsep [ptext SLIT("class"), ppr sty clas, ptext SLIT("method"),
+ ppr sty occ])
patMonoBindsCtxt pbind sty
- = ppHang (ppStr "In a pattern binding:")
+ = hang (ptext SLIT("In a pattern binding:"))
4 (ppr sty pbind)
methodSigCtxt name ty sty
- = ppHang (ppBesides [ppStr "When matching the definition of class method `",
- ppr sty name, ppStr "' to its signature :" ])
+ = hang (hsep [ptext SLIT("When matching the definition of class method"),
+ ppr sty name, ptext SLIT("to its signature :") ])
4 (ppr sty ty)
bindSigCtxt method_ids sty
- = ppHang (ppStr "When checking type signatures for: ")
- 4 (ppInterleave (ppStr ", ") (map (ppr sty) method_ids))
+ = hang (ptext SLIT("When checking type signatures for: "))
+ 4 (hsep (punctuate comma (map (ppr sty) method_ids)))
superClassSigCtxt sty
- = ppStr "When checking superclass constraints on instance declaration"
+ = ptext SLIT("When checking superclass constraints on instance declaration")
\end{code}
projects / ghc-hetmet.git / blobdiff