\begin{code}
module TcClassDcl ( tcClassSigs, tcClassDecl2,
findMethodBind, instantiateMethod, tcInstanceMethodBody,
- mkGenericDefMethBind, getGenericInstances, mkDefMethRdrName,
+ mkGenericDefMethBind, getGenericInstances,
tcAddDeclCtxt, badMethodErr, badATErr, omittedATWarn
) where
import HsSyn
import RnHsSyn
import RnExpr
-import RnEnv
import Inst
import InstEnv
+import TcPat( addInlinePrags )
import TcEnv
import TcBinds
-import TcSimplify
+import TcUnify
import TcHsType
import TcMType
import TcType
import TcRnMonad
+import BuildTyCl( TcMethInfo )
import Generics
import Class
import TyCon
import Var
import NameEnv
import NameSet
-import RdrName
import Outputable
import PrelNames
import DynFlags
-> LHsBinds Name
-> TcM [TcMethInfo]
-type TcMethInfo = (Name, DefMeth, Type) -- A temporary intermediate, to communicate
- -- between tcClassSigs and buildClass
tcClassSigs clas sigs def_methods
- = do { dm_env <- checkDefaultBinds clas op_names def_methods
- ; mapM (tcClassSig dm_env) op_sigs }
+ = do { dm_env <- mapM (addLocM (checkDefaultBind clas op_names))
+ (bagToList def_methods)
+ ; mapM (tcClassSig (mkNameEnv dm_env)) op_sigs }
where
op_sigs = [sig | sig@(L _ (TypeSig _ _)) <- sigs]
op_names = [n | (L _ (TypeSig (L _ n) _)) <- op_sigs]
-
-checkDefaultBinds :: Name -> [Name] -> LHsBinds Name -> TcM (NameEnv Bool)
+checkDefaultBind :: Name -> [Name] -> HsBindLR Name Name -> TcM (Name, DefMethSpec)
-- Check default bindings
-- a) must be for a class op for this class
-- b) must be all generic or all non-generic
- -- and return a mapping from class-op to Bool
- -- where True <=> it's a generic default method
-checkDefaultBinds clas ops binds
- = do dm_infos <- mapM (addLocM (checkDefaultBind clas ops)) (bagToList binds)
- return (mkNameEnv dm_infos)
-
-checkDefaultBind :: Name -> [Name] -> HsBindLR Name Name -> TcM (Name, Bool)
checkDefaultBind clas ops (FunBind {fun_id = L _ op, fun_matches = MatchGroup matches _ })
= do { -- Check that the op is from this class
- checkTc (op `elem` ops) (badMethodErr clas op)
+ checkTc (op `elem` ops) (badMethodErr clas op)
-- Check that all the defns ar generic, or none are
- ; checkTc (all_generic || none_generic) (mixedGenericErr op)
-
- ; return (op, all_generic)
+ ; case (none_generic, all_generic) of
+ (True, _) -> return (op, VanillaDM)
+ (_, True) -> return (op, GenericDM)
+ _ -> failWith (mixedGenericErr op)
}
where
n_generic = count (isJust . maybeGenericMatch) matches
none_generic = n_generic == 0
all_generic = matches `lengthIs` n_generic
+
checkDefaultBind _ _ b = pprPanic "checkDefaultBind" (ppr b)
-tcClassSig :: NameEnv Bool -- Info about default methods;
+tcClassSig :: NameEnv DefMethSpec -- Info about default methods;
-> LSig Name
-> TcM TcMethInfo
tcClassSig dm_env (L loc (TypeSig (L _ op_name) op_hs_ty))
= setSrcSpan loc $ do
{ op_ty <- tcHsKindedType op_hs_ty -- Class tyvars already in scope
- ; let dm = case lookupNameEnv dm_env op_name of
- Nothing -> NoDefMeth
- Just False -> DefMeth
- Just True -> GenDefMeth
+ ; let dm = lookupNameEnv dm_env op_name `orElse` NoDM
; return (op_name, dm, op_ty) }
tcClassSig _ s = pprPanic "tcClassSig" (ppr s)
\end{code}
\begin{code}
tcClassDecl2 :: LTyClDecl Name -- The class declaration
- -> TcM ([Id], LHsBinds Id)
+ -> TcM (LHsBinds Id)
tcClassDecl2 (L loc (ClassDecl {tcdLName = class_name, tcdSigs = sigs,
tcdMeths = default_binds}))
- = recoverM (return ([], emptyLHsBinds)) $
- setSrcSpan loc $
+ = recoverM (return emptyLHsBinds) $
+ setSrcSpan loc $
do { clas <- tcLookupLocatedClass class_name
-- We make a separate binding for each default method.
(tyvars, _, _, op_items) = classBigSig clas
rigid_info = ClsSkol clas
prag_fn = mkPragFun sigs default_binds
- sig_fn = mkTcSigFun sigs
+ sig_fn = mkSigFun sigs
clas_tyvars = tcSkolSigTyVars rigid_info tyvars
pred = mkClassPred clas (mkTyVarTys clas_tyvars)
- ; inst_loc <- getInstLoc (SigOrigin rigid_info)
- ; this_dict <- newDictBndr inst_loc pred
+ ; this_dict <- newEvVar pred
; let tc_dm = tcDefMeth clas clas_tyvars
this_dict default_binds
sig_fn prag_fn
- -- tc_dm is called only for a sel_id
- -- that has a binding in default_binds
-
- dm_sel_ids = [sel_id | (sel_id, DefMeth) <- op_items]
- -- Generate code for polymorphic default methods only (hence DefMeth)
- -- (Generic default methods have turned into instance decls by now.)
- -- This is incompatible with Hugs, which expects a polymorphic
- -- default method for every class op, regardless of whether or not
- -- the programmer supplied an explicit default decl for the class.
- -- (If necessary we can fix that, but we don't have a convenient Id to hand.)
- ; (dm_ids, defm_binds) <- tcExtendTyVarEnv clas_tyvars $
- mapAndUnzipM tc_dm dm_sel_ids
+ ; dm_binds <- tcExtendTyVarEnv clas_tyvars $
+ mapM tc_dm op_items
- ; return (dm_ids, listToBag defm_binds) }
+ ; return (listToBag (catMaybes dm_binds)) }
tcClassDecl2 d = pprPanic "tcClassDecl2" (ppr d)
-tcDefMeth :: Class -> [TyVar] -> Inst -> LHsBinds Name
- -> TcSigFun -> TcPragFun -> Id
- -> TcM (Id, LHsBind Id)
-tcDefMeth clas tyvars this_dict binds_in sig_fn prag_fn sel_id
- = do { let sel_name = idName sel_id
- ; dm_name <- lookupTopBndrRn (mkDefMethRdrName sel_name)
- ; local_dm_name <- newLocalName sel_name
- -- Base the local_dm_name on the selector name, becuase
+tcDefMeth :: Class -> [TyVar] -> EvVar -> LHsBinds Name
+ -> SigFun -> PragFun -> ClassOpItem
+ -> TcM (Maybe (LHsBind Id))
+-- Generate code for polymorphic default methods only (hence DefMeth)
+-- (Generic default methods have turned into instance decls by now.)
+-- This is incompatible with Hugs, which expects a polymorphic
+-- default method for every class op, regardless of whether or not
+-- the programmer supplied an explicit default decl for the class.
+-- (If necessary we can fix that, but we don't have a convenient Id to hand.)
+tcDefMeth clas tyvars this_dict binds_in sig_fn prag_fn (sel_id, dm_info)
+ = case dm_info of
+ NoDefMeth -> return Nothing
+ GenDefMeth -> return Nothing
+ DefMeth dm_name -> do
+ { let sel_name = idName sel_id
+ ; local_dm_name <- newLocalName sel_name
+ -- Base the local_dm_name on the selector name, because
-- type errors from tcInstanceMethodBody come from here
-- See Note [Silly default-method bind]
-- (possibly out of date)
- ; let meth_bind = findMethodBind sel_name local_dm_name binds_in
+ ; let meth_bind = findMethodBind sel_name binds_in
`orElse` pprPanic "tcDefMeth" (ppr sel_id)
- -- We only call tcDefMeth on selectors for which
- -- there is a binding in binds_in
+ -- dm_info = DefMeth dm_name only if there is a binding in binds_in
- dm_sig_fn _ = sig_fn sel_name
- dm_ty = idType sel_id
- dm_id = mkDefaultMethodId dm_name dm_ty
+ dm_sig_fn _ = sig_fn sel_name
+ dm_id = mkDefaultMethodId sel_id dm_name
local_dm_type = instantiateMethod clas sel_id (mkTyVarTys tyvars)
local_dm_id = mkLocalId local_dm_name local_dm_type
+ prags = prag_fn sel_name
- ; (dm_id_w_inline, spec_prags)
- <- tcPrags NonRecursive False True dm_id (prag_fn sel_name)
+ ; dm_id_w_inline <- addInlinePrags dm_id prags
+ ; spec_prags <- tcSpecPrags dm_id prags
; warnTc (not (null spec_prags))
(ptext (sLit "Ignoring SPECIALISE pragmas on default method")
<+> quotes (ppr sel_name))
- ; tcInstanceMethodBody (instLoc this_dict)
- tyvars [this_dict]
- ([], emptyBag)
+ ; liftM Just $
+ tcInstanceMethodBody (ClsSkol clas)
+ tyvars
+ [this_dict]
+ Nothing
dm_id_w_inline local_dm_id
dm_sig_fn IsDefaultMethod meth_bind }
---------------
-tcInstanceMethodBody :: InstLoc -> [TcTyVar] -> [Inst]
- -> ([Inst], LHsBinds Id) -> Id -> Id
- -> TcSigFun -> TcSpecPrags -> LHsBind Name
- -> TcM (Id, LHsBind Id)
-tcInstanceMethodBody inst_loc tyvars dfun_dicts
- (this_dict, this_bind) meth_id local_meth_id
- meth_sig_fn spec_prags bind@(L loc _)
+tcInstanceMethodBody :: SkolemInfo -> [TcTyVar] -> [EvVar]
+ -> Maybe EvBind
+ -> Id -> Id
+ -> SigFun -> TcSpecPrags -> LHsBind Name
+ -> TcM (LHsBind Id)
+tcInstanceMethodBody skol_info tyvars dfun_ev_vars
+ this_dict meth_id local_meth_id
+ meth_sig_fn specs
+ (L loc bind)
= do { -- Typecheck the binding, first extending the envt
-- so that when tcInstSig looks up the local_meth_id to find
-- its signature, we'll find it in the environment
- ; ((tc_bind, _), lie) <- getLIE $
- tcExtendIdEnv [local_meth_id] $
- tcPolyBinds TopLevel meth_sig_fn no_prag_fn
- NonRecursive NonRecursive
- (unitBag bind)
-
- ; let avails = this_dict ++ dfun_dicts
- -- Only need the this_dict stuff if there are type
- -- variables involved; otherwise overlap is not possible
- -- See Note [Subtle interaction of recursion and overlap]
- -- in TcInstDcls
- ; lie_binds <- tcSimplifyCheck inst_loc tyvars avails lie
-
- ; let full_bind = AbsBinds tyvars dfun_lam_vars
- [(tyvars, meth_id, local_meth_id, spec_prags)]
- (this_bind `unionBags` lie_binds
- `unionBags` tc_bind)
-
- dfun_lam_vars = map instToVar dfun_dicts -- Includes equalities
-
- ; return (meth_id, L loc full_bind) }
+ let full_given = case this_dict of
+ Nothing -> dfun_ev_vars
+ Just (EvBind dict _) -> dict : dfun_ev_vars
+ lm_bind = L loc (bind { fun_id = L loc (idName local_meth_id) })
+ -- Substitue the local_meth_name for the binder
+ -- NB: the binding is always a FunBind
+
+ ; (ev_binds, (tc_bind, _))
+ <- checkConstraints skol_info tyvars full_given $
+ tcExtendIdEnv [local_meth_id] $
+ tcPolyBinds TopLevel meth_sig_fn no_prag_fn
+ NonRecursive NonRecursive
+ [lm_bind]
+
+ -- Add the binding for this_dict, if we have one
+ ; ev_binds' <- case this_dict of
+ Nothing -> return ev_binds
+ Just (EvBind self rhs) -> extendTcEvBinds ev_binds self rhs
+
+ ; let full_bind = AbsBinds { abs_tvs = tyvars, abs_ev_vars = dfun_ev_vars
+ , abs_exports = [(tyvars, meth_id, local_meth_id, specs)]
+ , abs_ev_binds = ev_binds'
+ , abs_binds = tc_bind }
+
+ ; return (L loc full_bind) }
where
no_prag_fn _ = [] -- No pragmas for local_meth_id;
-- they are all for meth_id
\end{code}
\begin{code}
-mkDefMethRdrName :: Name -> RdrName
-mkDefMethRdrName sel_name = mkDerivedRdrName sel_name mkDefaultMethodOcc
-
instantiateMethod :: Class -> Id -> [TcType] -> TcType
-- Take a class operation, say
-- op :: forall ab. C a => forall c. Ix c => (b,c) -> a
---------------------------
--- The renamer just puts the selector ID as the binder in the method binding
--- but we must use the method name; so we substitute it here. Crude but simple.
-findMethodBind :: Name -> Name -- Selector and method name
+findMethodBind :: Name -- Selector name
-> LHsBinds Name -- A group of bindings
- -> Maybe (LHsBind Name) -- The binding, with meth_name replacing sel_name
-findMethodBind sel_name meth_name binds
+ -> Maybe (LHsBind Name) -- The binding
+findMethodBind sel_name binds
= foldlBag mplus Nothing (mapBag f binds)
where
- f (L loc1 bind@(FunBind { fun_id = L loc2 op_name }))
- | op_name == sel_name
- = Just (L loc1 (bind { fun_id = L loc2 meth_name }))
- f _other = Nothing
+ f bind@(L _ (FunBind { fun_id = L _ op_name }))
+ | op_name == sel_name
+ = Just bind
+ f _other = Nothing
\end{code}
Note [Polymorphic methods]
op Unit = ...
\begin{code}
-mkGenericDefMethBind :: Class -> [Type] -> Id -> Name -> TcM (LHsBind Name)
-mkGenericDefMethBind clas inst_tys sel_id meth_name
+mkGenericDefMethBind :: Class -> [Type] -> Id -> TcM (LHsBind Name)
+mkGenericDefMethBind clas inst_tys sel_id
= -- A generic default method
-- If the method is defined generically, we can only do the job if the
-- instance declaration is for a single-parameter type class with
-- Rename it before returning it
; (rn_rhs, _) <- rnLExpr rhs
- ; return (noLoc $ mkFunBind (noLoc meth_name) [mkSimpleMatch [] rn_rhs]) }
+ ; return (noLoc $ mkFunBind (noLoc (idName sel_id))
+ [mkSimpleMatch [] rn_rhs]) }
where
rhs = mkGenericRhs sel_id clas_tyvar tycon
badGenericInstanceType :: LHsBinds Name -> SDoc
badGenericInstanceType binds
= vcat [ptext (sLit "Illegal type pattern in the generic bindings"),
- nest 4 (ppr binds)]
+ nest 2 (ppr binds)]
missingGenericInstances :: [Name] -> SDoc
missingGenericInstances missing
dupGenericInsts :: [(TyCon, InstInfo a)] -> SDoc
dupGenericInsts tc_inst_infos
= vcat [ptext (sLit "More than one type pattern for a single generic type constructor:"),
- nest 4 (vcat (map ppr_inst_ty tc_inst_infos)),
+ nest 2 (vcat (map ppr_inst_ty tc_inst_infos)),
ptext (sLit "All the type patterns for a generic type constructor must be identical")
]
where
projects / ghc-hetmet.git / blobdiff