\section[TcClassDcl]{Typechecking class declarations}
\begin{code}
-module TcClassDcl ( kcClassDecl, tcClassDecl1, tcClassDecls2, tcMethodBind, badMethodErr ) where
+module TcClassDcl ( kcClassDecl, tcClassDecl1, tcClassDecls2, mkImplicitClassBinds,
+ tcMethodBind, checkFromThisClass
+ ) where
#include "HsVersions.h"
import HsSyn ( HsDecl(..), TyClDecl(..), Sig(..), MonoBinds(..),
InPat(..), HsBinds(..), GRHSs(..),
- HsExpr(..), HsLit(..), HsType(..), pprClassAssertion,
- unguardedRHS, andMonoBinds, andMonoBindList, getTyVarName,
- isClassDecl
+ HsExpr(..), HsLit(..), HsType(..), HsPred(..),
+ pprHsClassAssertion, unguardedRHS,
+ andMonoBinds, andMonoBindList, getTyVarName,
+ isClassDecl, isClassOpSig, isPragSig, collectMonoBinders
)
import HsPragmas ( ClassPragmas(..) )
-import BasicTypes ( NewOrData(..), TopLevelFlag(..), RecFlag(..), StrictnessMark(..) )
+import BasicTypes ( NewOrData(..), TopLevelFlag(..), RecFlag(..) )
import RnHsSyn ( RenamedTyClDecl, RenamedClassPragmas,
RenamedClassOpSig, RenamedMonoBinds,
RenamedContext, RenamedHsDecl, RenamedSig
)
-import TcHsSyn ( TcMonoBinds )
+import TcHsSyn ( TcMonoBinds, idsToMonoBinds )
-import Inst ( Inst, InstOrigin(..), LIE, emptyLIE, plusLIE, newDicts, newMethod )
+import Inst ( Inst, InstOrigin(..), LIE, emptyLIE, plusLIE, plusLIEs, newDicts, newMethod )
import TcEnv ( TcId, ValueEnv, TcTyThing(..), tcAddImportedIdInfo,
tcLookupClass, tcLookupTy, tcExtendTyVarEnvForMeths, tcExtendGlobalTyVars,
tcExtendLocalValEnv
)
-import TcBinds ( tcBindWithSigs, tcPragmaSigs )
+import TcBinds ( tcBindWithSigs, tcSpecSigs )
import TcUnify ( unifyKinds )
import TcMonad
import TcMonoType ( tcHsType, tcHsTopType, tcExtendTopTyVarScope,
)
import TcSimplify ( tcSimplifyAndCheck, bindInstsOfLocalFuns )
import TcType ( TcType, TcTyVar, tcInstTyVars, zonkTcTyVarBndr, tcGetTyVar )
-import PrelVals ( nO_METHOD_BINDING_ERROR_ID )
+import TcInstUtil ( classDataCon )
+import PrelInfo ( nO_METHOD_BINDING_ERROR_ID )
import FieldLabel ( firstFieldLabelTag )
-import Bag ( unionManyBags )
-import Class ( mkClass, classBigSig, Class )
+import Bag ( unionManyBags, bagToList )
+import Class ( mkClass, classBigSig, classSelIds, Class, ClassOpItem )
import CmdLineOpts ( opt_GlasgowExts, opt_WarnMissingMethods )
-import MkId ( mkSuperDictSelId, mkDataConId,
- mkMethodSelId, mkDefaultMethodId
- )
-import DataCon ( mkDataCon )
-import Id ( Id,
- getIdUnfolding, idType, idName
- )
-import CoreUnfold ( getUnfoldingTemplate )
+import MkId ( mkDictSelId, mkDataConId, mkDataConWrapId, mkDefaultMethodId )
+import DataCon ( mkDataCon, dataConId, dataConWrapId, notMarkedStrict )
+import Id ( Id, setInlinePragma, idUnfolding, idType, idName )
+import CoreUnfold ( unfoldingTemplate )
import IdInfo
-import Name ( Name, isLocallyDefined, NamedThing(..) )
+import Name ( Name, nameOccName, isLocallyDefined, NamedThing(..) )
+import NameSet ( emptyNameSet )
import Outputable
-import Type ( mkFunTy, mkTyVarTy, mkTyVarTys, mkDictTy,
- mkSigmaTy, mkForAllTys, Type, ThetaType,
+import Type ( Type, ThetaType, ClassContext,
+ mkFunTy, mkTyVarTy, mkTyVarTys, mkDictTy,
+ mkSigmaTy, mkForAllTys, mkClassPred, classesOfPreds,
boxedTypeKind, mkArrowKind
)
import Var ( tyVarKind, TyVar )
import Unique ( Unique, Uniquable(..) )
import Util
import Maybes ( seqMaybe )
-
-
--- import TcPragmas ( tcGenPragmas, tcClassOpPragmas )
-tcGenPragmas ty id ps = returnNF_Tc noIdInfo
-tcClassOpPragmas ty sel def spec ps = returnNF_Tc (spec `setSpecInfo` noIdInfo,
- noIdInfo)
+import FiniteMap ( lookupWithDefaultFM )
\end{code}
\begin{code}
kcClassDecl (ClassDecl context class_name
- tyvar_names class_sigs def_methods pragmas
- tycon_name datacon_name src_loc)
+ tyvar_names fundeps class_sigs def_methods pragmas
+ _ _ _ _ src_loc)
= -- CHECK ARITY 1 FOR HASKELL 1.4
checkTc (opt_GlasgowExts || length tyvar_names == 1)
(classArityErr class_name) `thenTc_`
-- The net effect is to mutate the class kind
tcExtendTopTyVarScope kind tyvar_names $ \ _ _ ->
tcContext context `thenTc_`
- mapTc kc_sig class_sigs `thenTc_`
+ mapTc kc_sig the_class_sigs `thenTc_`
returnTc ()
where
- kc_sig (ClassOpSig _ _ op_ty loc) = tcAddSrcLoc loc (tcHsType op_ty)
+ the_class_sigs = filter isClassOpSig class_sigs
+
+ kc_sig (ClassOpSig _ _ _ op_ty loc) = tcAddSrcLoc loc (tcHsType op_ty)
\end{code}
%************************************************************************
\begin{code}
-tcClassDecl1 rec_env rec_inst_mapper
+tcClassDecl1 rec_env rec_inst_mapper rec_vrcs
(ClassDecl context class_name
- tyvar_names class_sigs def_methods pragmas
- tycon_name datacon_name src_loc)
+ tyvar_names fundeps class_sigs def_methods pragmas
+ tycon_name datacon_name datacon_wkr_name sc_sel_names src_loc)
= -- LOOK THINGS UP IN THE ENVIRONMENT
tcLookupTy class_name `thenTc` \ (class_kind, _, AClass rec_class) ->
tcExtendTopTyVarScope class_kind tyvar_names $ \ tyvars _ ->
-- CHECK THE CONTEXT
-- traceTc (text "tcClassCtxt" <+> ppr class_name) `thenTc_`
- tcClassContext class_name rec_class tyvars context pragmas
+ tcClassContext class_name rec_class tyvars context sc_sel_names
`thenTc` \ (sc_theta, sc_tys, sc_sel_ids) ->
-- traceTc (text "tcClassCtxt done" <+> ppr class_name) `thenTc_`
+ -- CHECK THE FUNCTIONAL DEPENDENCIES,
+ tcFundeps fundeps `thenTc` \ fds ->
+
-- CHECK THE CLASS SIGNATURES,
- mapTc (tcClassSig rec_env rec_class tyvars) class_sigs
+ mapTc (tcClassSig rec_env rec_class tyvars)
+ (filter isClassOpSig class_sigs)
`thenTc` \ sig_stuff ->
-- MAKE THE CLASS OBJECT ITSELF
let
- (op_tys, op_sel_ids, defm_ids) = unzip3 sig_stuff
+ (op_tys, op_items) = unzip sig_stuff
rec_class_inst_env = rec_inst_mapper rec_class
- clas = mkClass class_name tyvars
- sc_theta sc_sel_ids op_sel_ids defm_ids
+ clas = mkClass class_name tyvars fds
+ sc_theta sc_sel_ids op_items
tycon
rec_class_inst_env
other -> DataType
dict_con = mkDataCon datacon_name
- [NotMarkedStrict | _ <- dict_component_tys]
+ [notMarkedStrict | _ <- dict_component_tys]
[{- No labelled fields -}]
tyvars
[{-No context-}]
[{-No existential tyvars-}] [{-Or context-}]
dict_component_tys
- tycon dict_con_id
- dict_con_id = mkDataConId dict_con
+ tycon dict_con_id dict_wrap_id
+
+ dict_con_id = mkDataConId datacon_wkr_name dict_con
+ dict_wrap_id = mkDataConWrapId dict_con
+
+ argvrcs = lookupWithDefaultFM rec_vrcs (pprPanic "tcClassDecl1: argvrcs:" $
+ ppr tycon_name)
+ tycon_name
tycon = mkAlgTyCon tycon_name
class_kind
tyvars
[] -- No context
+ argvrcs
[dict_con] -- Constructors
[] -- No derivings
(Just clas) -- Yes! It's a dictionary
returnTc clas
\end{code}
+\begin{code}
+tcFundeps = mapTc tc_fundep
+tc_fundep (us, vs) =
+ mapTc tc_fd_tyvar us `thenTc` \ us' ->
+ mapTc tc_fd_tyvar vs `thenTc` \ vs' ->
+ returnTc (us', vs')
+tc_fd_tyvar v =
+ tcLookupTy v `thenTc` \(_, _, thing) ->
+ case thing of
+ ATyVar tv -> returnTc tv
+ -- ZZ else should fail more gracefully
+\end{code}
\begin{code}
tcClassContext :: Name -> Class -> [TyVar]
-> RenamedContext -- class context
- -> RenamedClassPragmas -- pragmas for superclasses
- -> TcM s (ThetaType, -- the superclass context
+ -> [Name] -- Names for superclass selectors
+ -> TcM s (ClassContext, -- the superclass context
[Type], -- types of the superclass dictionaries
[Id]) -- superclass selector Ids
-tcClassContext class_name rec_class rec_tyvars context pragmas
+tcClassContext class_name rec_class rec_tyvars context sc_sel_names
= -- Check the context.
-- The renamer has already checked that the context mentions
-- only the type variable of the class decl.
tcContext context `thenTc` \ sc_theta ->
let
- sc_tys = [mkDictTy sc tys | (sc,tys) <- sc_theta]
+ sc_theta' = classesOfPreds sc_theta
+ sc_tys = [mkDictTy sc tys | (sc,tys) <- sc_theta']
+ sc_sel_ids = zipWithEqual "tcClassContext" mk_super_id sc_sel_names sc_tys
in
-
- -- Make super-class selector ids
- -- We number them off, 1, 2, 3 etc so that we can construct
- -- names for the selectors. Thus
- -- class (C a, C b) => D a b where ...
- -- gives superclass selectors
- -- D_sc1, D_sc2
- -- (We used to call them D_C, but now we can have two different
- -- superclasses both called C!)
- mapTc mk_super_id (sc_theta `zip` [firstFieldLabelTag..]) `thenTc` \ sc_sel_ids ->
-
-- Done
- returnTc (sc_theta, sc_tys, sc_sel_ids)
+ returnTc (sc_theta', sc_tys, sc_sel_ids)
where
rec_tyvar_tys = mkTyVarTys rec_tyvars
- mk_super_id ((super_class, tys), index)
- = tcGetUnique `thenNF_Tc` \ uniq ->
- let
- ty = mkForAllTys rec_tyvars $
- mkFunTy (mkDictTy rec_class rec_tyvar_tys) (mkDictTy super_class tys)
- in
- returnTc (mkSuperDictSelId uniq rec_class index ty)
+ mk_super_id name dict_ty
+ = mkDictSelId name rec_class ty
+ where
+ ty = mkForAllTys rec_tyvars $
+ mkFunTy (mkDictTy rec_class rec_tyvar_tys) dict_ty
- check_constraint (c, tys) = checkTc (all is_tyvar tys)
- (superClassErr class_name (c, tys))
+ check_constraint (HsPClass c tys) = checkTc (all is_tyvar tys)
+ (superClassErr class_name (c, tys))
is_tyvar (MonoTyVar _) = True
is_tyvar other = False
-> [TyVar] -- The class type variable, used for error check only
-> RenamedClassOpSig
-> TcM s (Type, -- Type of the method
- Id, -- selector id
- Maybe Id) -- default-method ids
+ ClassOpItem) -- Selector Id, default-method Id, True if explicit default binding
+
tcClassSig rec_env rec_clas rec_clas_tyvars
- (ClassOpSig op_name maybe_dm_name
- op_ty
- src_loc)
+ (ClassOpSig op_name dm_name explicit_dm
+ op_ty src_loc)
= tcAddSrcLoc src_loc $
-- Check the type signature. NB that the envt *already has*
tcHsTopType op_ty `thenTc` \ local_ty ->
let
global_ty = mkSigmaTy rec_clas_tyvars
- [(rec_clas, mkTyVarTys rec_clas_tyvars)]
+ [mkClassPred rec_clas (mkTyVarTys rec_clas_tyvars)]
local_ty
-- Build the selector id and default method id
- sel_id = mkMethodSelId op_name rec_clas global_ty
- maybe_dm_id = case maybe_dm_name of
- Nothing -> Nothing
- Just dm_name -> let
- dm_id = mkDefaultMethodId dm_name rec_clas global_ty
- in
- Just (tcAddImportedIdInfo rec_env dm_id)
+ sel_id = mkDictSelId op_name rec_clas global_ty
+ dm_id = mkDefaultMethodId dm_name rec_clas global_ty
+ final_dm_id = tcAddImportedIdInfo rec_env dm_id
in
-- traceTc (text "tcClassSig done" <+> ppr op_name) `thenTc_`
- returnTc (local_ty, sel_id, maybe_dm_id)
+ returnTc (local_ty, (sel_id, final_dm_id, explicit_dm))
\end{code}
-> NF_TcM s (LIE, TcMonoBinds)
tcClassDecl2 (ClassDecl context class_name
- tyvar_names class_sigs default_binds pragmas _ _ src_loc)
+ tyvar_names _ class_sigs default_binds pragmas _ _ _ _ src_loc)
| not (isLocallyDefined class_name)
= returnNF_Tc (emptyLIE, EmptyMonoBinds)
| otherwise -- It is locally defined
= recoverNF_Tc (returnNF_Tc (emptyLIE, EmptyMonoBinds)) $
tcAddSrcLoc src_loc $
-
- -- Get the relevant class
tcLookupClass class_name `thenNF_Tc` \ clas ->
- let
- (tyvars, sc_theta, sc_sel_ids, op_sel_ids, defm_ids) = classBigSig clas
+ tcDefaultMethodBinds clas default_binds class_sigs
+\end{code}
+\begin{code}
+mkImplicitClassBinds :: [Class] -> NF_TcM s ([Id], TcMonoBinds)
+mkImplicitClassBinds classes
+ = returnNF_Tc (concat cls_ids_s, andMonoBindList binds_s)
-- The selector binds are already in the selector Id's unfoldings
--- sel_binds = [ CoreMonoBind sel_id (getUnfoldingTemplate (getIdUnfolding sel_id))
--- | sel_id <- sc_sel_ids ++ op_sel_ids,
--- isLocallyDefined sel_id
--- ]
---
--- final_sel_binds = andMonoBindList sel_binds
- in
- -- Generate bindings for the default methods
- tcDefaultMethodBinds clas default_binds `thenTc` \ (const_insts, meth_binds) ->
+ where
+ (cls_ids_s, binds_s) = unzip (map mk_implicit classes)
+
+ mk_implicit clas = (all_cls_ids, binds)
+ where
+ dict_con = classDataCon clas
+ all_cls_ids = dataConId dict_con : cls_ids
+ cls_ids = dataConWrapId dict_con : classSelIds clas
- returnTc (const_insts, meth_binds)
--- final_sel_binds `AndMonoBinds` meth_binds)
--- Leave 'em out for now. They always get inlined anyway. SLPJ June '98
+ -- The wrapper and selectors get bindings, the worker does not
+ binds | isLocallyDefined clas = idsToMonoBinds cls_ids
+ | otherwise = EmptyMonoBinds
\end{code}
%************************************************************************
defm.Foo.op1 :: forall a. Foo a => a -> Bool
defm.Foo.op1 = /\a -> \dfoo -> \x -> True
-====================== OLD ==================
-\begin{verbatim}
-defm.Foo.op2 :: forall a, b. (Foo a, Ord b) => a -> b -> b -> b
-defm.Foo.op2 = /\ a b -> \ dfoo dord -> \x y z ->
- if (op1 a dfoo x) && (< b dord y z) then y else z
-\end{verbatim}
-Notice that, like all ids, the foralls of defm.Foo.op2 are at the top.
-====================== END OF OLD ===================
-
-NEW:
-\begin{verbatim}
defm.Foo.op2 :: forall a. Foo a => forall b. Ord b => a -> b -> b -> b
defm.Foo.op2 = /\ a -> \ dfoo -> /\ b -> \ dord -> \x y z ->
if (op1 a dfoo x) && (< b dord y z) then y else z
\end{verbatim}
-
When we come across an instance decl, we may need to use the default
methods:
\begin{verbatim}
tcDefaultMethodBinds
:: Class
-> RenamedMonoBinds
+ -> [RenamedSig]
-> TcM s (LIE, TcMonoBinds)
-tcDefaultMethodBinds clas default_binds
- = -- Construct suitable signatures
- tcInstTyVars tyvars `thenNF_Tc` \ (clas_tyvars, inst_tys, inst_env) ->
-
- -- Typecheck the default bindings
- let
- theta = [(clas,inst_tys)]
- tc_dm sel_id_w_dm@(_, Just dm_id)
- = tcMethodBind clas origin clas_tyvars inst_tys theta
- default_binds [{-no prags-}] False
- sel_id_w_dm `thenTc` \ (bind, insts, (_, local_dm_id)) ->
- returnTc (bind, insts, (clas_tyvars, dm_id, local_dm_id))
- in
- tcExtendTyVarEnvForMeths tyvars clas_tyvars (
- mapAndUnzip3Tc tc_dm sel_ids_w_dms
- ) `thenTc` \ (defm_binds, insts_needed, abs_bind_stuff) ->
+tcDefaultMethodBinds clas default_binds sigs
+ = -- Check that the default bindings come from this class
+ checkFromThisClass clas op_items default_binds `thenNF_Tc_`
+ -- Do each default method separately
+ -- For Hugs compatibility we make a default-method for every
+ -- class op, regardless of whether or not the programmer supplied an
+ -- explicit default decl for the class. GHC will actually never
+ -- call the default method for such operations, because it'll whip up
+ -- a more-informative default method at each instance decl.
+ mapAndUnzipTc tc_dm op_items `thenTc` \ (defm_binds, const_lies) ->
- -- Check the context
- newDicts origin theta `thenNF_Tc` \ (this_dict, [this_dict_id]) ->
- let
- avail_insts = this_dict
- in
- tcAddErrCtxt (defltMethCtxt clas) $
+ returnTc (plusLIEs const_lies, andMonoBindList defm_binds)
+ where
+ prags = filter isPragSig sigs
- -- tcMethodBind has checked that the class_tyvars havn't
- -- been unified with each other or another type, but we must
- -- still zonk them before passing them to tcSimplifyAndCheck
- mapNF_Tc zonkTcTyVarBndr clas_tyvars `thenNF_Tc` \ clas_tyvars' ->
+ (tyvars, _, _, op_items) = classBigSig clas
- tcSimplifyAndCheck
- (ptext SLIT("class") <+> ppr clas)
- (mkVarSet clas_tyvars')
- avail_insts
- (unionManyBags insts_needed) `thenTc` \ (const_lie, dict_binds) ->
+ origin = ClassDeclOrigin
- let
- full_binds = AbsBinds
- clas_tyvars'
- [this_dict_id]
- abs_bind_stuff
- (dict_binds `andMonoBinds` andMonoBindList defm_binds)
- in
- returnTc (const_lie, full_binds)
+ -- We make a separate binding for each default method.
+ -- At one time I used a single AbsBinds for all of them, thus
+ -- AbsBind [d] [dm1, dm2, dm3] { dm1 = ...; dm2 = ...; dm3 = ... }
+ -- But that desugars into
+ -- ds = \d -> (..., ..., ...)
+ -- dm1 = \d -> case ds d of (a,b,c) -> a
+ -- And since ds is big, it doesn't get inlined, so we don't get good
+ -- default methods. Better to make separate AbsBinds for each
+
+ tc_dm op_item@(_, dm_id, _)
+ = tcInstTyVars tyvars `thenNF_Tc` \ (clas_tyvars, inst_tys, _) ->
+ let
+ theta = [(mkClassPred clas inst_tys)]
+ in
+ newDicts origin theta `thenNF_Tc` \ (this_dict, [this_dict_id]) ->
+ let
+ avail_insts = this_dict
+ in
+ tcExtendTyVarEnvForMeths tyvars clas_tyvars (
+ tcMethodBind clas origin clas_tyvars inst_tys theta
+ default_binds prags False
+ op_item
+ ) `thenTc` \ (defm_bind, insts_needed, (_, local_dm_id)) ->
+
+ tcAddErrCtxt (defltMethCtxt clas) $
+
+ -- tcMethodBind has checked that the class_tyvars havn't
+ -- been unified with each other or another type, but we must
+ -- still zonk them before passing them to tcSimplifyAndCheck
+ mapNF_Tc zonkTcTyVarBndr clas_tyvars `thenNF_Tc` \ clas_tyvars' ->
+
+ -- Check the context
+ tcSimplifyAndCheck
+ (ptext SLIT("class") <+> ppr clas)
+ (mkVarSet clas_tyvars')
+ avail_insts
+ insts_needed `thenTc` \ (const_lie, dict_binds) ->
+
+ let
+ full_bind = AbsBinds
+ clas_tyvars'
+ [this_dict_id]
+ [(clas_tyvars', dm_id, local_dm_id)]
+ emptyNameSet -- No inlines (yet)
+ (dict_binds `andMonoBinds` defm_bind)
+ in
+ returnTc (full_bind, const_lie)
+\end{code}
+\begin{code}
+checkFromThisClass :: Class -> [ClassOpItem] -> RenamedMonoBinds -> NF_TcM s ()
+checkFromThisClass clas op_items mono_binds
+ = mapNF_Tc check_from_this_class bndrs `thenNF_Tc_`
+ returnNF_Tc ()
where
- (tyvars, sc_theta, sc_sel_ids, op_sel_ids, defm_ids) = classBigSig clas
-
- sel_ids_w_dms = [pair | pair@(_, Just _) <- op_sel_ids `zip` defm_ids]
- -- Just the ones for which there is an explicit
- -- user default declaration
-
- origin = ClassDeclOrigin
+ check_from_this_class (bndr, loc)
+ | nameOccName bndr `elem` sel_names = returnNF_Tc ()
+ | otherwise = tcAddSrcLoc loc $
+ addErrTc (badMethodErr bndr clas)
+ sel_names = [getOccName sel_id | (sel_id,_,_) <- op_items]
+ bndrs = bagToList (collectMonoBinders mono_binds)
\end{code}
+
@tcMethodBind@ is used to type-check both default-method and
instance-decl method declarations. We must type-check methods one at a
-- the caller; here, it's just used for the error message
-> RenamedMonoBinds -- Method binding (pick the right one from in here)
-> [RenamedSig] -- Pramgas (just for this one)
- -> Bool -- True <=> supply default decl if no explicit decl
- -- This is true for instance decls,
- -- false for class decls
- -> (Id, Maybe Id) -- The method selector and default-method Id
+ -> Bool -- True <=> This method is from an instance declaration
+ -> ClassOpItem -- The method selector and default-method Id
-> TcM s (TcMonoBinds, LIE, (LIE, TcId))
tcMethodBind clas origin inst_tyvars inst_tys inst_theta
- meth_binds prags supply_default_bind
- (sel_id, maybe_dm_id)
+ meth_binds prags is_inst_decl
+ (sel_id, dm_id, explicit_dm)
= tcGetSrcLoc `thenNF_Tc` \ loc ->
newMethod origin sel_id inst_tys `thenNF_Tc` \ meth@(_, meth_id) ->
maybe_user_bind = find_bind meth_name meth_binds
no_user_bind = case maybe_user_bind of {Nothing -> True; other -> False}
- no_user_default = case maybe_dm_id of {Nothing -> True; other -> False}
meth_bind = case maybe_user_bind of
Just bind -> bind
in
-- Warn if no method binding, only if -fwarn-missing-methods
- if no_user_bind && not supply_default_bind then
- pprPanic "tcMethodBind" (ppr clas <+> ppr inst_tys)
- else
- warnTc (opt_WarnMissingMethods && no_user_bind && no_user_default)
+ warnTc (is_inst_decl && opt_WarnMissingMethods && no_user_bind && not explicit_dm)
(omittedMethodWarn sel_id clas) `thenNF_Tc_`
- -- Check the pragmas
- tcExtendLocalValEnv [(meth_name, meth_id)] (
- tcPragmaSigs meth_prags
- ) `thenTc` \ (prag_info_fn, prag_binds1, prag_lie) ->
-
-- Check the bindings; first add inst_tyvars to the envt
-- so that we don't quantify over them in nested places
-- The *caller* put the class/inst decl tyvars into the envt
tcExtendGlobalTyVars (mkVarSet inst_tyvars) (
tcAddErrCtxt (methodCtxt sel_id) $
- tcBindWithSigs NotTopLevel meth_bind [sig_info]
- NonRecursive prag_info_fn
+ tcBindWithSigs NotTopLevel meth_bind
+ [sig_info] meth_prags NonRecursive
) `thenTc` \ (binds, insts, _) ->
+ tcExtendLocalValEnv [(meth_name, meth_id)] (
+ tcSpecSigs meth_prags
+ ) `thenTc` \ (prag_binds1, prag_lie) ->
+
-- The prag_lie for a SPECIALISE pragma will mention the function
-- itself, so we have to simplify them away right now lest they float
-- outwards!
-- Find the prags for this method, and replace the
-- selector name with the method name
find_prags meth_name [] = []
- find_prags meth_name (SpecSig name ty spec loc : prags)
- | name == sel_name = SpecSig meth_name ty spec loc : find_prags meth_name prags
- find_prags meth_name (InlineSig name loc : prags)
- | name == sel_name = InlineSig meth_name loc : find_prags meth_name prags
- find_prags meth_name (NoInlineSig name loc : prags)
- | name == sel_name = NoInlineSig meth_name loc : find_prags meth_name prags
+ find_prags meth_name (SpecSig name ty loc : prags)
+ | name == sel_name = SpecSig meth_name ty loc : find_prags meth_name prags
+ find_prags meth_name (InlineSig name phase loc : prags)
+ | name == sel_name = InlineSig meth_name phase loc : find_prags meth_name prags
+ find_prags meth_name (NoInlineSig name phase loc : prags)
+ | name == sel_name = NoInlineSig meth_name phase loc : find_prags meth_name prags
find_prags meth_name (prag:prags) = find_prags meth_name prags
mk_default_bind local_meth_name loc
loc
default_expr loc
- = case maybe_dm_id of
- Just dm_id -> HsVar (getName dm_id) -- There's a default method
- Nothing -> error_expr loc -- No default method
+ | explicit_dm = HsVar (getName dm_id) -- There's a default method
+ | otherwise = error_expr loc -- No default method
error_expr loc = HsApp (HsVar (getName nO_METHOD_BINDING_ERROR_ID))
(HsLit (HsString (_PK_ (error_msg loc))))
= ptext SLIT("Too many parameters for class") <+> quotes (ppr class_name)
superClassErr class_name sc
- = ptext SLIT("Illegal superclass constraint") <+> quotes (pprClassAssertion sc)
+ = ptext SLIT("Illegal superclass constraint") <+> quotes (pprHsClassAssertion sc)
<+> ptext SLIT("in declaration for class") <+> quotes (ppr class_name)
defltMethCtxt class_name