\begin{code}
#include "HsVersions.h"
-module TcClassDcl (
- tcClassDecl1, tcClassDecls2
- ) where
+module TcClassDcl ( tcClassDecl1, tcClassDecls2, tcMethodBind ) where
-import Ubiq
+IMP_Ubiq()
-import HsSyn ( ClassDecl(..), HsBinds(..), Bind(..), MonoBinds(..),
- Match(..), GRHSsAndBinds(..), GRHS(..), HsExpr(..),
- HsLit(..), OutPat(..), Sig(..), PolyType(..), MonoType,
- Stmt, Qual, ArithSeqInfo, InPat, Fake )
+import HsSyn ( HsDecl(..), ClassDecl(..), HsBinds(..), MonoBinds(..),
+ Match(..), GRHSsAndBinds(..), GRHS(..), HsExpr(..),
+ DefaultDecl, TyDecl, InstDecl, IfaceSig, Fixity,
+ HsLit(..), OutPat(..), Sig(..), HsType(..), HsTyVar, InPat(..),
+ SYN_IE(RecFlag), nonRecursive, andMonoBinds, collectMonoBinders,
+ Stmt, DoOrListComp, ArithSeqInfo, Fake )
+import HsTypes ( getTyVarName )
import HsPragmas ( ClassPragmas(..) )
import RnHsSyn ( RenamedClassDecl(..), RenamedClassPragmas(..),
- RenamedClassOpSig(..), RenamedMonoBinds(..),
- RenamedGenPragmas(..), RenamedContext(..),
- RnName{-instance Uniquable-}
+ RenamedClassOpSig(..), SYN_IE(RenamedMonoBinds),
+ RenamedGenPragmas(..), RenamedContext(..), SYN_IE(RenamedHsDecl)
)
-import TcHsSyn ( TcIdOcc(..), TcHsBinds(..), TcMonoBinds(..), TcExpr(..),
- mkHsTyApp, mkHsTyLam, mkHsDictApp, mkHsDictLam, unZonkId )
-
+import TcHsSyn ( SYN_IE(TcHsBinds), SYN_IE(TcMonoBinds), SYN_IE(TcExpr),
+ mkHsTyApp, mkHsTyLam, mkHsDictApp, mkHsDictLam, tcIdType )
+
+import Inst ( Inst, InstOrigin(..), SYN_IE(LIE), emptyLIE, plusLIE, newDicts, newMethod )
+import TcEnv ( tcLookupClass, tcLookupTyVar, tcLookupTyCon, newLocalIds, tcAddImportedIdInfo,
+ tcExtendGlobalTyVars )
+import TcBinds ( tcBindWithSigs, TcSigInfo(..) )
+import TcKind ( unifyKind, TcKind )
import TcMonad
-import Inst ( Inst, InstOrigin(..), LIE(..), emptyLIE, plusLIE, newDicts )
-import TcEnv ( tcLookupClass, tcLookupTyVar, tcLookupTyCon, newLocalIds)
-import TcInstDcls ( processInstBinds )
-import TcKind ( unifyKind )
-import TcMonoType ( tcMonoType, tcContext )
-import TcType ( TcType(..), TcTyVar(..), tcInstType, tcInstSigTyVars )
-import TcKind ( TcKind )
-
-import Bag ( foldBag )
-import Class ( GenClass, mkClass, mkClassOp, getClassBigSig,
- getClassOps, getClassOpString, getClassOpLocalType )
-import CoreUtils ( escErrorMsg )
-import Id ( mkSuperDictSelId, mkMethodSelId, mkDefaultMethodId,
- idType )
-import IdInfo ( noIdInfo )
-import Name ( isLocallyDefined, moduleNamePair, getLocalName )
-import PrelVals ( pAT_ERROR_ID )
-import PprStyle
+import TcMonoType ( tcHsType, tcContext )
+import TcSimplify ( tcSimplifyAndCheck )
+import TcType ( TcIdOcc(..), SYN_IE(TcType), SYN_IE(TcTyVar), tcInstType, tcInstSigTyVars,
+ tcInstSigType, tcInstSigTcType )
+import PragmaInfo ( PragmaInfo(..) )
+
+import Bag ( bagToList, unionManyBags )
+import Class ( GenClass, mkClass, classBigSig,
+ classDefaultMethodId,
+ classOpTagByOccName, SYN_IE(Class)
+ )
+import CmdLineOpts ( opt_PprUserLength )
+import Id ( GenId, mkSuperDictSelId, mkMethodSelId,
+ mkDefaultMethodId, getIdUnfolding,
+ idType, SYN_IE(Id)
+ )
+import CoreUnfold ( getUnfoldingTemplate )
+import IdInfo
+import Name ( Name, isLocallyDefined, moduleString, getSrcLoc, nameOccName,
+ nameString, NamedThing(..) )
+import Outputable
import Pretty
-import PprType ( GenType, GenTyVar, GenClassOp )
-import SpecEnv ( SpecEnv(..) )
+import PprType ( GenClass, GenType, GenTyVar )
+import SpecEnv ( SpecEnv )
import SrcLoc ( mkGeneratedSrcLoc )
-import Type ( mkFunTy, mkTyVarTy, mkTyVarTys, mkDictTy,
- mkForAllTy, mkSigmaTy, splitSigmaTy)
+import Type ( mkFunTy, mkTyVarTy, mkTyVarTys, mkDictTy, splitRhoTy,
+ mkForAllTy, mkSigmaTy, splitSigmaTy, SYN_IE(Type)
+ )
import TysWiredIn ( stringTy )
-import TyVar ( GenTyVar )
-import Unique ( Unique )
+import TyVar ( unitTyVarSet, GenTyVar, SYN_IE(TyVar) )
+import Unique ( Unique, Uniquable(..) )
import Util
+
-- import TcPragmas ( tcGenPragmas, tcClassOpPragmas )
tcGenPragmas ty id ps = returnNF_Tc noIdInfo
-tcClassOpPragmas ty sel def spec ps = returnNF_Tc (noIdInfo, noIdInfo)
-
+tcClassOpPragmas ty sel def spec ps = returnNF_Tc (noIdInfo `addSpecInfo` spec,
+ noIdInfo)
\end{code}
+
+
+Dictionary handling
+~~~~~~~~~~~~~~~~~~~
+Every class implicitly declares a new data type, corresponding to dictionaries
+of that class. So, for example:
+
+ class (D a) => C a where
+ op1 :: a -> a
+ op2 :: forall b. Ord b => a -> b -> b
+
+would implicitly declare
+
+ data CDict a = CDict (D a)
+ (a -> a)
+ (forall b. Ord b => a -> b -> b)
+
+(We could use a record decl, but that means changing more of the existing apparatus.
+One step at at time!)
+
+For classes with just one superclass+method, we use a newtype decl instead:
+
+ class C a where
+ op :: forallb. a -> b -> b
+
+generates
+
+ newtype CDict a = CDict (forall b. a -> b -> b)
+
+Now DictTy in Type is just a form of type synomym:
+ DictTy c t = TyConTy CDict `AppTy` t
+
+Death to "ExpandingDicts".
+
+
\begin{code}
-tcClassDecl1 rec_inst_mapper
+tcClassDecl1 rec_env rec_inst_mapper
(ClassDecl context class_name
tyvar_name class_sigs def_methods pragmas src_loc)
= tcAddSrcLoc src_loc $
tcAddErrCtxt (classDeclCtxt class_name) $
-- LOOK THINGS UP IN THE ENVIRONMENT
- tcLookupClass class_name `thenNF_Tc` \ (class_kind, rec_class) ->
- tcLookupTyVar tyvar_name `thenNF_Tc` \ (tyvar_kind, rec_tyvar) ->
+ tcLookupClass class_name `thenTc` \ (class_kind, rec_class) ->
+ tcLookupTyVar (getTyVarName tyvar_name) `thenNF_Tc` \ (tyvar_kind, rec_tyvar) ->
let
- (rec_class_inst_env, rec_class_op_inst_fn) = rec_inst_mapper rec_class
+ rec_class_inst_env = rec_inst_mapper rec_class
in
-- FORCE THE CLASS AND ITS TYVAR TO HAVE SAME KIND
`thenTc` \ (scs, sc_sel_ids) ->
-- CHECK THE CLASS SIGNATURES,
- mapTc (tcClassSig rec_class rec_tyvar rec_class_op_inst_fn) class_sigs
+ mapTc (tcClassSig rec_env rec_class rec_tyvar) class_sigs
`thenTc` \ sig_stuff ->
-- MAKE THE CLASS OBJECT ITSELF
- tcGetUnique `thenNF_Tc` \ uniq ->
let
- (ops, op_sel_ids, defm_ids) = unzip3 sig_stuff
- clas = mkClass uniq (getName class_name) rec_tyvar
- scs sc_sel_ids ops op_sel_ids defm_ids
+ (op_sel_ids, defm_ids) = unzip sig_stuff
+ clas = mkClass (uniqueOf class_name) (getName class_name) rec_tyvar
+ scs sc_sel_ids op_sel_ids defm_ids
rec_class_inst_env
in
returnTc clas
\end{code}
+ let
+ clas_ty = mkTyVarTy clas_tyvar
+ dict_component_tys = classDictArgTys clas_ty
+ new_or_data = case dict_component_tys of
+ [_] -> NewType
+ other -> DataType
+
+ dict_con_id = mkDataCon class_name
+ [NotMarkedStrict]
+ [{- No labelled fields -}]
+ [clas_tyvar]
+ [{-No context-}]
+ dict_component_tys
+ tycon
+
+ tycon = mkDataTyCon class_name
+ (tyVarKind rec_tyvar `mkArrowKind` mkBoxedTypeKind)
+ [rec_tyvar]
+ [{- Empty context -}]
+ [dict_con_id]
+ [{- No derived classes -}]
+ new_or_data
+ in
+
+
\begin{code}
tcClassContext :: Class -> TyVar
-> RenamedContext -- class context
in
-- Make super-class selector ids
- mapTc (mk_super_id rec_class)
- (super_classes `zip` maybe_pragmas) `thenTc` \ sc_sel_ids ->
+ mapTc (mk_super_id rec_class) super_classes `thenTc` \ sc_sel_ids ->
-- Done
returnTc (super_classes, sc_sel_ids)
where
- mk_super_id rec_class (super_class, maybe_pragma)
- = fixTc ( \ rec_super_id ->
- tcGetUnique `thenNF_Tc` \ uniq ->
-
- -- GET THE PRAGMA INFO FOR THE SUPERCLASS
- (case maybe_pragma of
- Nothing -> returnNF_Tc noIdInfo
- Just prag -> tcGenPragmas Nothing{-ty unknown-} rec_super_id prag
- ) `thenNF_Tc` \ id_info ->
- let
- ty = mkForAllTy rec_tyvar (
- mkFunTy (mkDictTy rec_class (mkTyVarTy rec_tyvar))
- (mkDictTy super_class (mkTyVarTy rec_tyvar))
- )
- in
- -- BUILD THE SUPERCLASS ID
- returnTc (mkSuperDictSelId uniq rec_class super_class ty id_info)
- )
-
- maybe_pragmas :: [Maybe RenamedGenPragmas]
- maybe_pragmas = case pragmas of
- NoClassPragmas -> repeat Nothing
- SuperDictPragmas prags -> ASSERT(length prags == length context)
- map Just prags
- -- If there are any pragmas there should
- -- be one for each superclass
+ rec_tyvar_ty = mkTyVarTy rec_tyvar
+ mk_super_id rec_class super_class
+ = tcGetUnique `thenNF_Tc` \ uniq ->
+ let
+ ty = mkForAllTy rec_tyvar $
+ mkFunTy (mkDictTy rec_class rec_tyvar_ty)
+ (mkDictTy super_class rec_tyvar_ty)
+ in
+ returnTc (mkSuperDictSelId uniq rec_class super_class ty)
-tcClassSig :: Class -- Knot tying only!
+tcClassSig :: TcEnv s -- Knot tying only!
+ -> Class -- ...ditto...
-> TyVar -- The class type variable, used for error check only
- -> (ClassOp -> SpecEnv) -- Ditto; the spec info for the class ops
-> RenamedClassOpSig
- -> TcM s (ClassOp, -- class op
- Id, -- selector id
- Id) -- default-method ids
-
-tcClassSig rec_clas rec_clas_tyvar rec_classop_spec_fn
- (ClassOpSig op_name
- (HsForAllTy tyvar_names context monotype)
- pragmas src_loc)
+ -> TcM s (Id, -- selector id
+ Maybe Id) -- default-method ids
+
+tcClassSig rec_env rec_clas rec_clas_tyvar
+ (ClassOpSig op_name maybe_dm_name
+ op_ty
+ src_loc)
= tcAddSrcLoc src_loc $
- fixTc ( \ ~(_, rec_sel_id, rec_defm_id) -> -- Knot for pragmas
-- Check the type signature. NB that the envt *already has*
-- bindings for the type variables; see comments in TcTyAndClassDcls.
- tcContext context `thenTc` \ theta ->
- tcMonoType monotype `thenTc` \ tau ->
- mapAndUnzipNF_Tc tcLookupTyVar tyvar_names `thenNF_Tc` \ (_,tyvars) ->
+
+ -- NB: Renamer checks that the class type variable is mentioned in local_ty,
+ -- and that it is not constrained by theta
+ tcHsType op_ty `thenTc` \ local_ty ->
let
- full_tyvars = rec_clas_tyvar : tyvars
- full_theta = (rec_clas, mkTyVarTy rec_clas_tyvar) : theta
- global_ty = mkSigmaTy full_tyvars full_theta tau
- local_ty = mkSigmaTy tyvars theta tau
- class_op = mkClassOp (getLocalName op_name)
- (panic "(getTagFromClassOpName op_name)TcClassDecl"{-(getTagFromClassOpName op_name)-})
- local_ty
+ global_ty = mkSigmaTy [rec_clas_tyvar]
+ [(rec_clas, mkTyVarTy rec_clas_tyvar)]
+ local_ty
in
- -- Munch the pragmas
- tcClassOpPragmas
- global_ty
- rec_sel_id rec_defm_id
- (rec_classop_spec_fn class_op)
- pragmas `thenNF_Tc` \ (op_info, defm_info) ->
-
-- Build the selector id and default method id
- tcGetUnique `thenNF_Tc` \ d_uniq ->
let
- op_uniq = uniqueOf op_name
- sel_id = mkMethodSelId op_uniq rec_clas class_op global_ty op_info
- defm_id = mkDefaultMethodId d_uniq rec_clas class_op False global_ty defm_info
- -- ToDo: improve the "False"
+ 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)
in
- returnTc (class_op, sel_id, defm_id)
- )
+ returnTc (sel_id, maybe_dm_id)
\end{code}
each local class decl.
\begin{code}
-tcClassDecls2 :: Bag RenamedClassDecl
- -> NF_TcM s (LIE s, TcHsBinds s)
+tcClassDecls2 :: [RenamedHsDecl]
+ -> NF_TcM s (LIE s, TcMonoBinds s)
tcClassDecls2 decls
- = foldBag combine
- tcClassDecl2
- (returnNF_Tc (emptyLIE, EmptyBinds))
- decls
+ = foldr combine
+ (returnNF_Tc (emptyLIE, EmptyMonoBinds))
+ [tcClassDecl2 cls_decl | ClD cls_decl <- decls]
where
combine tc1 tc2 = tc1 `thenNF_Tc` \ (lie1, binds1) ->
tc2 `thenNF_Tc` \ (lie2, binds2) ->
returnNF_Tc (lie1 `plusLIE` lie2,
- binds1 `ThenBinds` binds2)
+ binds1 `AndMonoBinds` binds2)
\end{code}
@tcClassDecl2@ is the business end of things.
\begin{code}
tcClassDecl2 :: RenamedClassDecl -- The class declaration
- -> NF_TcM s (LIE s, TcHsBinds s)
+ -> NF_TcM s (LIE s, TcMonoBinds s)
tcClassDecl2 (ClassDecl context class_name
tyvar_name class_sigs default_binds pragmas src_loc)
| not (isLocallyDefined class_name)
- = returnNF_Tc (emptyLIE, EmptyBinds)
+ = returnNF_Tc (emptyLIE, EmptyMonoBinds)
| otherwise -- It is locally defined
- = recoverNF_Tc (returnNF_Tc (emptyLIE, EmptyBinds)) $
- tcAddSrcLoc src_loc $
+ = recoverNF_Tc (returnNF_Tc (emptyLIE, EmptyMonoBinds)) $
+ tcAddSrcLoc src_loc $
-- Get the relevant class
- tcLookupClass class_name `thenNF_Tc` \ (_, clas) ->
- let
- (tyvar, scs, sc_sel_ids, ops, op_sel_ids, defm_ids)
- = getClassBigSig clas
- in
- tcInstSigTyVars [tyvar] `thenNF_Tc` \ ([clas_tyvar], _, _) ->
-
- -- Generate bindings for the selector functions
- buildSelectors clas tyvar clas_tyvar scs sc_sel_ids ops op_sel_ids
- `thenNF_Tc` \ sel_binds ->
- -- Ditto for the methods
- buildDefaultMethodBinds clas clas_tyvar defm_ids default_binds
- `thenTc` \ (const_insts, meth_binds) ->
-
- returnTc (const_insts, sel_binds `ThenBinds` meth_binds)
-\end{code}
-
-%************************************************************************
-%* *
-\subsection[ClassDcl-bld-sels]{Building the selector functions for methods and superclasses}
-%* *
-%************************************************************************
-
-\begin{code}
-buildSelectors :: Class -- The class object
- -> TyVar -- Class type variable
- -> TcTyVar s -- Instantiated class type variable (TyVarTy)
- -> [Class] -> [Id] -- Superclasses and selectors
- -> [ClassOp] -> [Id] -- Class ops and selectors
- -> NF_TcM s (TcHsBinds s)
-
-buildSelectors clas clas_tyvar clas_tc_tyvar scs sc_sel_ids ops op_sel_ids
- =
- -- Make new Ids for the components of the dictionary
+ tcLookupClass class_name `thenTc` \ (_, clas) ->
let
- clas_tyvar_ty = mkTyVarTy clas_tc_tyvar
- mk_op_ty = tcInstType [(clas_tyvar, clas_tyvar_ty)] . getClassOpLocalType
- in
- mapNF_Tc mk_op_ty ops `thenNF_Tc` \ op_tys ->
- newLocalIds (map getClassOpString ops) op_tys `thenNF_Tc` \ method_ids ->
-
- newDicts ClassDeclOrigin
- [ (super_clas, clas_tyvar_ty)
- | super_clas <- scs ] `thenNF_Tc` \ (_,dict_ids) ->
+ (tyvar, scs, sc_sel_ids, op_sel_ids, defm_ids) = classBigSig clas
- newDicts ClassDeclOrigin
- [ (clas, clas_tyvar_ty) ] `thenNF_Tc` \ (_,[clas_dict]) ->
+ -- The selector binds are already in the selector Id's unfoldings
+ sel_binds = [ CoreMonoBind (RealId sel_id) (getUnfoldingTemplate (getIdUnfolding sel_id))
+ | sel_id <- sc_sel_ids ++ op_sel_ids,
+ isLocallyDefined sel_id
+ ]
- -- Make suitable bindings for the selectors
- let
- mk_sel sel_id method_or_dict
- = mkSelBind sel_id clas_tc_tyvar clas_dict dict_ids method_ids method_or_dict
+ final_sel_binds = andMonoBinds sel_binds
in
- listNF_Tc (zipWithEqual mk_sel op_sel_ids method_ids) `thenNF_Tc` \ op_sel_binds ->
- listNF_Tc (zipWithEqual mk_sel sc_sel_ids dict_ids) `thenNF_Tc` \ sc_sel_binds ->
-
- returnNF_Tc (SingleBind (
- NonRecBind (
- foldr AndMonoBinds
- (foldr AndMonoBinds EmptyMonoBinds op_sel_binds)
- sc_sel_binds
- )))
-\end{code}
+ -- Generate bindings for the default methods
+ tcDefaultMethodBinds clas default_binds `thenTc` \ (const_insts, meth_binds) ->
-%************************************************************************
-%* *
-\subsection[ClassDcl-misc]{Miscellaneous}
-%* *
-%************************************************************************
-
-Make a selector expression for @sel_id@ from a dictionary @clas_dict@
-consisting of @dicts@ and @methods@.
-
-We have to do a bit of jiggery pokery to get the type variables right.
-Suppose we have the class decl:
-\begin{verbatim}
- class Foo a where
- op1 :: Ord b => a -> b -> a
- op2 :: ...
-\end{verbatim}
-Then the method selector for \tr{op1} is like this:
-\begin{verbatim}
- op1_sel = /\a b -> \dFoo dOrd -> case dFoo of
- (op1_method,op2_method) -> op1_method b dOrd
-\end{verbatim}
-Note that the type variable for \tr{b} and the (Ord b) dictionary
-are lifted to the top lambda, and
-\tr{op1_method} is applied to them. This is preferable to the alternative:
-\begin{verbatim}
- op1_sel' = /\a -> \dFoo -> case dFoo of
- (op1_method,op2_method) -> op1_method
-\end{verbatim}
-because \tr{op1_sel'} then has the rather strange type
-\begin{verbatim}
- op1_sel' :: forall a. Foo a -> forall b. Ord b -> a -> b -> a
-\end{verbatim}
-whereas \tr{op1_sel} (the one we use) has the decent type
-\begin{verbatim}
- op1_sel :: forall a b. Foo a -> Ord b -> a -> b -> a
-\end{verbatim}
-
-NOTE that we return a TcMonoBinds (which is later zonked) even though
-there's no real back-substitution to do. It's just simpler this way!
-
-NOTE ALSO that the selector has no free type variables, so we
-don't bother to instantiate the class-op's local type; instead
-we just use the variables inside it.
-
-\begin{code}
-mkSelBind :: Id -- the selector id
- -> TcTyVar s -> TcIdOcc s -- class tyvar and dict
- -> [TcIdOcc s] -> [TcIdOcc s] -- superclasses and methods in class dict
- -> TcIdOcc s -- the superclass/method being slected
- -> NF_TcM s (TcMonoBinds s)
-
-mkSelBind sel_id clas_tyvar clas_dict dicts methods method_or_dict@(TcId op)
- = let
- (op_tyvars,op_theta,op_tau) = splitSigmaTy (idType op)
- op_tys = mkTyVarTys op_tyvars
- in
- newDicts ClassDeclOrigin op_theta `thenNF_Tc` \ (_, op_dicts) ->
-
- -- sel_id = /\ clas_tyvar op_tyvars -> \ clas_dict op_dicts ->
- -- case clas_dict of
- -- <dicts..methods> -> method_or_dict op_tyvars op_dicts
-
- returnNF_Tc (VarMonoBind (RealId sel_id) (
- TyLam (clas_tyvar:op_tyvars) (
- DictLam (clas_dict:op_dicts) (
- HsCase
- (HsVar clas_dict)
- ([PatMatch (DictPat dicts methods) (
- GRHSMatch (GRHSsAndBindsOut
- [OtherwiseGRHS
- (mkHsDictApp (mkHsTyApp (HsVar method_or_dict) op_tys) op_dicts)
- mkGeneratedSrcLoc]
- EmptyBinds
- op_tau))])
- mkGeneratedSrcLoc
- ))))
+ returnTc (const_insts,
+ final_sel_binds `AndMonoBinds` meth_binds)
\end{code}
-
%************************************************************************
%* *
\subsection[Default methods]{Default methods}
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:
const.Foo.Int.op1 = defm.Foo.op1 Int dfun.Foo.Int
const.Foo.Int.op2 :: forall b. Ord b => Int -> b -> b -> b
-const.Foo.Int.op2 = /\b -> defm.Foo.op2 Int b dfun.Foo.Int
+const.Foo.Int.op2 = defm.Foo.op2 Int dfun.Foo.Int
dfun.Foo.Int :: Foo Int
dfun.Foo.Int = (const.Foo.Int.op1, const.Foo.Int.op2)
\end{verbatim}
Notice that, as with method selectors above, we assume that dictionary
application is curried, so there's no need to mention the Ord dictionary
-in const.Foo.Int.op2
+in const.Foo.Int.op2 (or the type variable).
+
\begin{verbatim}
instance Foo a => Foo [a] where {}
= /\ a -> \ dfoo_a ->
let rec
op1 = defm.Foo.op1 [a] dfoo_list
- op2 = /\b -> \dord -> defm.Foo.op2 [a] b dfoo_list dord
+ op2 = defm.Foo.op2 [a] dfoo_list
dfoo_list = (op1, op2)
in
dfoo_list
\end{verbatim}
\begin{code}
-buildDefaultMethodBinds
+tcDefaultMethodBinds
:: Class
- -> TcTyVar s
- -> [Id]
-> RenamedMonoBinds
- -> TcM s (LIE s, TcHsBinds s)
-
-buildDefaultMethodBinds clas clas_tyvar
- default_method_ids default_binds
- = -- Deal with the method declarations themselves
- mapNF_Tc unZonkId default_method_ids `thenNF_Tc` \ tc_defm_ids ->
- processInstBinds
- (makeClassDeclDefaultMethodRhs clas default_method_ids)
- [] -- No tyvars in scope for "this inst decl"
- emptyLIE -- No insts available
- (map TcId tc_defm_ids)
- default_binds `thenTc` \ (dicts_needed, default_binds') ->
-
- returnTc (dicts_needed, SingleBind (NonRecBind default_binds'))
-\end{code}
+ -> TcM s (LIE s, TcMonoBinds s)
-@makeClassDeclDefaultMethodRhs@ builds the default method for a
-class declaration when no explicit default method is given.
+tcDefaultMethodBinds clas default_binds
+ = -- Construct suitable signatures
+ tcInstSigTyVars [tyvar] `thenNF_Tc` \ ([clas_tyvar], [inst_ty], inst_env) ->
-\begin{code}
-makeClassDeclDefaultMethodRhs
- :: Class
- -> [Id]
- -> Int
- -> NF_TcM s (TcExpr s)
-
-makeClassDeclDefaultMethodRhs clas method_ids tag
- = tcInstType [] (idType method_id) `thenNF_Tc` \ method_ty ->
- let
- (tyvars, theta, tau) = splitSigmaTy method_ty
- in
- newDicts ClassDeclOrigin theta `thenNF_Tc` \ (lie, dict_ids) ->
-
- returnNF_Tc (mkHsTyLam tyvars (
- mkHsDictLam dict_ids (
- HsApp (mkHsTyApp (HsVar (RealId pAT_ERROR_ID)) [tau])
- (HsLitOut (HsString (_PK_ error_msg)) stringTy))))
- where
- (clas_mod, clas_name) = moduleNamePair clas
+ -- Typecheck the default bindings
+ let
+ clas_tyvar_set = unitTyVarSet clas_tyvar
+
+ tc_dm meth_bind
+ = let
+ bndr_name = case meth_bind of
+ FunMonoBind name _ _ _ -> name
+ PatMonoBind (VarPatIn name) _ _ -> name
+
+ idx = classOpTagByOccName clas (nameOccName bndr_name) - 1
+ sel_id = op_sel_ids !! idx
+ Just dm_id = defm_ids !! idx
+ in
+ tcMethodBind clas origin inst_ty sel_id meth_bind
+ `thenTc` \ (bind, insts, (_, local_dm_id)) ->
+ returnTc (bind, insts, ([clas_tyvar], RealId dm_id, local_dm_id))
+ in
+ tcExtendGlobalTyVars clas_tyvar_set (
+ mapAndUnzip3Tc tc_dm (flatten default_binds [])
+ ) `thenTc` \ (defm_binds, insts_needed, abs_bind_stuff) ->
+
+ -- Check the context
+ newDicts origin [(clas,inst_ty)] `thenNF_Tc` \ (this_dict, [this_dict_id]) ->
+ let
+ avail_insts = this_dict
+ in
+ tcSimplifyAndCheck
+ clas_tyvar_set
+ avail_insts
+ (unionManyBags insts_needed) `thenTc` \ (const_lie, dict_binds) ->
- method_id = method_ids !! (tag-1)
- class_op = (getClassOps clas) !! (tag-1)
+ let
+ full_binds = AbsBinds
+ [clas_tyvar]
+ [this_dict_id]
+ abs_bind_stuff
+ (dict_binds `AndMonoBinds` andMonoBinds defm_binds)
+ in
+ returnTc (const_lie, full_binds)
- error_msg = "%D" -- => No default method for \"
- ++ unencoded_part_of_msg
+ where
+ (tyvar, scs, sc_sel_ids, op_sel_ids, defm_ids) = classBigSig clas
+ origin = ClassDeclOrigin
- unencoded_part_of_msg = escErrorMsg (
- _UNPK_ clas_mod ++ "." ++ _UNPK_ clas_name ++ "."
- ++ (ppShow 80 (ppr PprForUser class_op))
- ++ "\"" )
+ flatten EmptyMonoBinds rest = rest
+ flatten (AndMonoBinds b1 b2) rest = flatten b1 (flatten b2 rest)
+ flatten a_bind rest = a_bind : rest
\end{code}
+@tcMethodBind@ is used to type-check both default-method and
+instance-decl method declarations. We must type-check methods one at a
+time, because their signatures may have different contexts and
+tyvar sets.
+
+\begin{code}
+tcMethodBind
+ :: Class
+ -> InstOrigin s
+ -> TcType s -- Instance type
+ -> Id -- The method selector
+ -> RenamedMonoBinds -- Method binding (just one)
+ -> TcM s (TcMonoBinds s, LIE s, (LIE s, TcIdOcc s))
+
+tcMethodBind clas origin inst_ty sel_id meth_bind
+ = tcAddSrcLoc src_loc $
+ newMethod origin (RealId sel_id) [inst_ty] `thenNF_Tc` \ meth@(_, TcId local_meth_id) ->
+ tcInstSigTcType (idType local_meth_id) `thenNF_Tc` \ (tyvars', rho_ty') ->
+ let
+ (theta', tau') = splitRhoTy rho_ty'
+ sig_info = TySigInfo bndr_name local_meth_id tyvars' theta' tau' src_loc
+ in
+ tcBindWithSigs [bndr_name] meth_bind [sig_info]
+ nonRecursive (\_ -> NoPragmaInfo) `thenTc` \ (binds, insts, _) ->
+
+ returnTc (binds, insts, meth)
+ where
+ (bndr_name, src_loc) = case meth_bind of
+ FunMonoBind name _ _ loc -> (name, loc)
+ PatMonoBind (VarPatIn name) _ loc -> (name, loc)
+\end{code}
Contexts
~~~~~~~~
\begin{code}
classDeclCtxt class_name sty
- = ppCat [ppStr "In the class declaration for", ppr sty class_name]
+ = hsep [ptext SLIT("In the class declaration for"), ppr sty class_name]
\end{code}
projects / ghc-hetmet.git / blobdiff