\begin{code}
module TcClassDcl ( tcClassSigs, tcClassDecl2,
findMethodBind, instantiateMethod, tcInstanceMethodBody,
- mkGenericDefMethBind, getGenericInstances,
+ mkGenericDefMethBind,
tcAddDeclCtxt, badMethodErr, badATErr, omittedATWarn
) where
#include "HsVersions.h"
import HsSyn
-import RnHsSyn
-import RnExpr
-import Inst
-import InstEnv
-import TcPat( addInlinePrags )
import TcEnv
+import TcPat( addInlinePrags )
import TcBinds
import TcUnify
import TcHsType
import TcType
import TcRnMonad
import BuildTyCl( TcMethInfo )
-import Generics
import Class
-import TyCon
-import MkId
import Id
import Name
-import Var
-import VarSet
import NameEnv
import NameSet
+import Var
import Outputable
-import PrelNames
import DynFlags
import ErrUtils
-import Util
-import ListSetOps
import SrcLoc
import Maybes
import BasicTypes
import FastString
import Control.Monad
-import Data.List
\end{code}
%************************************************************************
\begin{code}
-tcClassSigs :: Name -- Name of the class
+tcClassSigs :: Name -- Name of the class
-> [LSig Name]
-> LHsBinds Name
- -> TcM [TcMethInfo]
-
+ -> TcM ([TcMethInfo], -- Exactly one for each method
+ NameEnv Type) -- Types of the generic-default methods
tcClassSigs clas sigs def_methods
- = 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]
-
-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
-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)
-
- -- Check that all the defns ar generic, or none are
- ; 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
+ = do { gen_dm_prs <- mapM (addLocM tc_gen_sig) gen_sigs
+ ; let gen_dm_env = mkNameEnv gen_dm_prs
-checkDefaultBind _ _ b = pprPanic "checkDefaultBind" (ppr b)
+ ; op_info <- mapM (addLocM (tc_sig gen_dm_env)) vanilla_sigs
+ ; let op_names = mkNameSet [ n | (n,_,_) <- op_info ]
+ ; sequence_ [ failWithTc (badMethodErr clas n)
+ | n <- dm_bind_names, not (n `elemNameSet` op_names) ]
+ -- Value binding for non class-method (ie no TypeSig)
-tcClassSig :: NameEnv DefMethSpec -- Info about default methods;
- -> LSig Name
- -> TcM TcMethInfo
+ ; sequence_ [ failWithTc (badGenericMethod clas n)
+ | (n,_) <- gen_dm_prs, not (n `elem` dm_bind_names) ]
+ -- Generic signature without value binding
-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 = lookupNameEnv dm_env op_name `orElse` NoDM
- ; return (op_name, dm, op_ty) }
-tcClassSig _ s = pprPanic "tcClassSig" (ppr s)
+ ; return (op_info, gen_dm_env) }
+ where
+ vanilla_sigs = [L loc (nm,ty) | L loc (TypeSig nm ty) <- sigs]
+ gen_sigs = [L loc (nm,ty) | L loc (GenericSig nm ty) <- sigs]
+ dm_bind_names :: [Name] -- These ones have a value binding in the class decl
+ dm_bind_names = [op | L _ (FunBind {fun_id = L _ op}) <- bagToList def_methods]
+
+ tc_sig genop_env (L _ op_name, op_hs_ty)
+ = do { op_ty <- tcHsKindedType op_hs_ty -- Class tyvars already in scope
+ ; let dm | op_name `elemNameEnv` genop_env = GenericDM
+ | op_name `elem` dm_bind_names = VanillaDM
+ | otherwise = NoDM
+ ; return (op_name, dm, op_ty) }
+
+ tc_gen_sig (L _ op_name, gen_hs_ty)
+ = do { gen_op_ty <- tcHsKindedType gen_hs_ty
+ ; return (op_name, gen_op_ty) }
\end{code}
-- default methods. Better to make separate AbsBinds for each
; let
(tyvars, _, _, op_items) = classBigSig clas
- rigid_info = ClsSkol clas
- prag_fn = mkPragFun sigs default_binds
+ prag_fn = mkPragFun sigs default_binds
sig_fn = mkSigFun sigs
- clas_tyvars = tcSkolSigTyVars rigid_info tyvars
+ clas_tyvars = tcSuperSkolTyVars tyvars
pred = mkClassPred clas (mkTyVarTys clas_tyvars)
; this_dict <- newEvVar pred
+ ; traceTc "TIM2" (ppr sigs)
; let tc_dm = tcDefMeth clas clas_tyvars
- this_dict default_binds
+ this_dict default_binds
sig_fn prag_fn
; dm_binds <- tcExtendTyVarEnv clas_tyvars $
mapM tc_dm op_items
- ; return (listToBag (catMaybes dm_binds)) }
+ ; return (unionManyBags dm_binds) }
tcClassDecl2 d = pprPanic "tcClassDecl2" (ppr d)
tcDefMeth :: Class -> [TyVar] -> EvVar -> LHsBinds Name
-> SigFun -> PragFun -> ClassOpItem
- -> TcM (Maybe (LHsBind Id))
+ -> TcM (LHsBinds TcId)
-- 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
-- (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 binds_in
- `orElse` pprPanic "tcDefMeth" (ppr sel_id)
- -- dm_info = DefMeth dm_name only if there is a binding in binds_in
-
- 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 <- 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))
-
- ; liftM Just $
- tcInstanceMethodBody (ClsSkol clas)
- tyvars
- [this_dict]
- Nothing
- dm_id_w_inline local_dm_id
- dm_sig_fn IsDefaultMethod meth_bind }
+ NoDefMeth -> do { mapM_ (addLocM (badDmPrag sel_id)) prags
+ ; return emptyBag }
+ DefMeth dm_name -> tc_dm dm_name
+ GenDefMeth dm_name -> tc_dm dm_name
+ where
+ sel_name = idName sel_id
+ prags = prag_fn sel_name
+ dm_sig_fn _ = sig_fn sel_name
+ dm_bind = findMethodBind sel_name binds_in
+ `orElse` pprPanic "tcDefMeth" (ppr sel_id)
+
+ -- Eg. class C a where
+ -- op :: forall b. Eq b => a -> [b] -> a
+ -- gen_op :: a -> a
+ -- generic gen_op :: D a => a -> a
+ -- The "local_dm_ty" is precisely the type in the above
+ -- type signatures, ie with no "forall a. C a =>" prefix
+
+ tc_dm dm_name
+ = do { dm_id <- tcLookupId dm_name
+ ; local_dm_name <- newLocalName sel_name
+ -- Base the local_dm_name on the selector name, because
+ -- type errors from tcInstanceMethodBody come from here
+
+ ; let local_dm_ty = instantiateMethod clas dm_id (mkTyVarTys tyvars)
+ local_dm_id = mkLocalId local_dm_name local_dm_ty
+
+ ; 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))
+
+ ; tc_bind <- tcInstanceMethodBody (ClsSkol clas) tyvars [this_dict]
+ dm_id_w_inline local_dm_id dm_sig_fn
+ IsDefaultMethod dm_bind
+
+ ; return (unitBag tc_bind) }
---------------
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_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
- 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
+ let lm_bind = L loc (bind { fun_id = L loc (idName local_meth_id) })
+ -- Substitute the local_meth_name for the binder
-- NB: the binding is always a FunBind
-
+ ; traceTc "TIM" (ppr local_meth_id $$ ppr (meth_sig_fn (idName local_meth_id)))
; (ev_binds, (tc_bind, _))
- <- checkConstraints skol_info emptyVarSet tyvars full_given $
+ <- checkConstraints skol_info tyvars dfun_ev_vars $
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
+ ; 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_ev_binds = ev_binds
, abs_binds = tc_bind }
; return (L loc full_bind) }
op Unit = ...
\begin{code}
-mkGenericDefMethBind :: Class -> [Type] -> Id -> TcM (LHsBind Name)
-mkGenericDefMethBind clas inst_tys sel_id
+mkGenericDefMethBind :: Class -> [Type] -> Id -> Name -> TcM (LHsBind Name)
+mkGenericDefMethBind clas inst_tys sel_id dm_name
= -- 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
- -- a type constructor applied to type arguments in the instance decl
- -- (checkTc, so False provokes the error)
- do { checkTc (isJust maybe_tycon)
- (badGenericInstance sel_id (notSimple inst_tys))
- ; checkTc (tyConHasGenerics tycon)
- (badGenericInstance sel_id (notGeneric tycon))
-
- ; dflags <- getDOpts
+ -- If the method is defined generically, we only have to call the
+ -- dm_name.
+ do { dflags <- getDOpts
; liftIO (dumpIfSet_dyn dflags Opt_D_dump_deriv "Filling in method body"
(vcat [ppr clas <+> ppr inst_tys,
nest 2 (ppr sel_id <+> equals <+> ppr rhs)]))
- -- Rename it before returning it
- ; (rn_rhs, _) <- rnLExpr rhs
; return (noLoc $ mkFunBind (noLoc (idName sel_id))
- [mkSimpleMatch [] rn_rhs]) }
+ [mkSimpleMatch [] rhs]) }
where
- rhs = mkGenericRhs sel_id clas_tyvar tycon
-
- -- The tycon is only used in the generic case, and in that
- -- case we require that the instance decl is for a single-parameter
- -- type class with type variable arguments:
- -- instance (...) => C (T a b)
- clas_tyvar = ASSERT (not (null (classTyVars clas))) head (classTyVars clas)
- Just tycon = maybe_tycon
- maybe_tycon = case inst_tys of
- [ty] -> case tcSplitTyConApp_maybe ty of
- Just (tycon, arg_tys) | all tcIsTyVarTy arg_tys -> Just tycon
- _ -> Nothing
- _ -> Nothing
-
-
----------------------------
-getGenericInstances :: [LTyClDecl Name] -> TcM [InstInfo Name]
-getGenericInstances class_decls
- = do { gen_inst_infos <- mapM (addLocM get_generics) class_decls
- ; let { gen_inst_info = concat gen_inst_infos }
-
- -- Return right away if there is no generic stuff
- ; if null gen_inst_info then return []
- else do
-
- -- Otherwise print it out
- { dflags <- getDOpts
- ; liftIO (dumpIfSet_dyn dflags Opt_D_dump_deriv "Generic instances"
- (vcat (map pprInstInfoDetails gen_inst_info)))
- ; return gen_inst_info }}
-
-get_generics :: TyClDecl Name -> TcM [InstInfo Name]
-get_generics decl@(ClassDecl {tcdLName = class_name, tcdMeths = def_methods})
- | null generic_binds
- = return [] -- The comon case: no generic default methods
-
- | otherwise -- A source class decl with generic default methods
- = recoverM (return []) $
- tcAddDeclCtxt decl $ do
- clas <- tcLookupLocatedClass class_name
-
- -- Group by type, and
- -- make an InstInfo out of each group
- let
- groups = groupWith listToBag generic_binds
-
- inst_infos <- mapM (mkGenericInstance clas) groups
-
- -- Check that there is only one InstInfo for each type constructor
- -- The main way this can fail is if you write
- -- f {| a+b |} ... = ...
- -- f {| x+y |} ... = ...
- -- Then at this point we'll have an InstInfo for each
- --
- -- The class should be unary, which is why simpleInstInfoTyCon should be ok
- let
- tc_inst_infos :: [(TyCon, InstInfo Name)]
- tc_inst_infos = [(simpleInstInfoTyCon i, i) | i <- inst_infos]
-
- bad_groups = [group | group <- equivClassesByUniq get_uniq tc_inst_infos,
- group `lengthExceeds` 1]
- get_uniq (tc,_) = getUnique tc
-
- mapM_ (addErrTc . dupGenericInsts) bad_groups
-
- -- Check that there is an InstInfo for each generic type constructor
- let
- missing = genericTyConNames `minusList` [tyConName tc | (tc,_) <- tc_inst_infos]
-
- checkTc (null missing) (missingGenericInstances missing)
-
- return inst_infos
- where
- generic_binds :: [(HsType Name, LHsBind Name)]
- generic_binds = getGenericBinds def_methods
-get_generics decl = pprPanic "get_generics" (ppr decl)
-
-
----------------------------------
-getGenericBinds :: LHsBinds Name -> [(HsType Name, LHsBind Name)]
- -- Takes a group of method bindings, finds the generic ones, and returns
- -- them in finite map indexed by the type parameter in the definition.
-getGenericBinds binds = concat (map getGenericBind (bagToList binds))
-
-getGenericBind :: LHsBindLR Name Name -> [(HsType Name, LHsBindLR Name Name)]
-getGenericBind (L loc bind@(FunBind { fun_matches = MatchGroup matches ty }))
- = groupWith wrap (mapCatMaybes maybeGenericMatch matches)
- where
- wrap ms = L loc (bind { fun_matches = MatchGroup ms ty })
-getGenericBind _
- = []
-
-groupWith :: ([a] -> b) -> [(HsType Name, a)] -> [(HsType Name, b)]
-groupWith _ [] = []
-groupWith op ((t,v):prs) = (t, op (v:vs)) : groupWith op rest
- where
- vs = map snd this
- (this,rest) = partition same_t prs
- same_t (t', _v) = t `eqPatType` t'
-
-eqPatLType :: LHsType Name -> LHsType Name -> Bool
-eqPatLType t1 t2 = unLoc t1 `eqPatType` unLoc t2
-
-eqPatType :: HsType Name -> HsType Name -> Bool
--- A very simple equality function, only for
--- type patterns in generic function definitions.
-eqPatType (HsTyVar v1) (HsTyVar v2) = v1==v2
-eqPatType (HsAppTy s1 t1) (HsAppTy s2 t2) = s1 `eqPatLType` s2 && t1 `eqPatLType` t2
-eqPatType (HsOpTy s1 op1 t1) (HsOpTy s2 op2 t2) = s1 `eqPatLType` s2 && t1 `eqPatLType` t2 && unLoc op1 == unLoc op2
-eqPatType (HsNumTy n1) (HsNumTy n2) = n1 == n2
-eqPatType (HsParTy t1) t2 = unLoc t1 `eqPatType` t2
-eqPatType t1 (HsParTy t2) = t1 `eqPatType` unLoc t2
-eqPatType _ _ = False
-
----------------------------------
-mkGenericInstance :: Class
- -> (HsType Name, LHsBinds Name)
- -> TcM (InstInfo Name)
-
-mkGenericInstance clas (hs_ty, binds) = do
- -- Make a generic instance declaration
- -- For example: instance (C a, C b) => C (a+b) where { binds }
-
- -- Extract the universally quantified type variables
- -- and wrap them as forall'd tyvars, so that kind inference
- -- works in the standard way
- let
- sig_tvs = userHsTyVarBndrs $ map noLoc $ nameSetToList $
- extractHsTyVars (noLoc hs_ty)
- hs_forall_ty = noLoc $ mkExplicitHsForAllTy sig_tvs (noLoc []) (noLoc hs_ty)
-
- -- Type-check the instance type, and check its form
- forall_inst_ty <- tcHsSigType GenPatCtxt hs_forall_ty
- let
- (tyvars, inst_ty) = tcSplitForAllTys forall_inst_ty
-
- checkTc (validGenericInstanceType inst_ty)
- (badGenericInstanceType binds)
-
- -- Make the dictionary function.
- span <- getSrcSpanM
- overlap_flag <- getOverlapFlag
- dfun_name <- newDFunName clas [inst_ty] span
- let
- inst_theta = [mkClassPred clas [mkTyVarTy tv] | tv <- tyvars]
- dfun_id = mkDictFunId dfun_name tyvars inst_theta clas [inst_ty]
- ispec = mkLocalInstance dfun_id overlap_flag
-
- return (InstInfo { iSpec = ispec, iBinds = VanillaInst binds [] False })
+ rhs = nlHsVar dm_name
\end{code}
-
%************************************************************************
%* *
Error messages
= hsep [ptext (sLit "Class"), quotes (ppr clas),
ptext (sLit "does not have a method"), quotes (ppr op)]
+badGenericMethod :: Outputable a => a -> Name -> SDoc
+badGenericMethod clas op
+ = hsep [ptext (sLit "Class"), quotes (ppr clas),
+ ptext (sLit "has a generic-default signature without a binding"), quotes (ppr op)]
+
badATErr :: Class -> Name -> SDoc
badATErr clas at
= hsep [ptext (sLit "Class"), quotes (ppr clas),
omittedATWarn :: Name -> SDoc
omittedATWarn at
= ptext (sLit "No explicit AT declaration for") <+> quotes (ppr at)
-
-badGenericInstance :: Var -> SDoc -> SDoc
-badGenericInstance sel_id because
- = sep [ptext (sLit "Can't derive generic code for") <+> quotes (ppr sel_id),
- because]
-
-notSimple :: [Type] -> SDoc
-notSimple inst_tys
- = vcat [ptext (sLit "because the instance type(s)"),
- nest 2 (ppr inst_tys),
- ptext (sLit "is not a simple type of form (T a1 ... an)")]
-
-notGeneric :: TyCon -> SDoc
-notGeneric tycon
- = vcat [ptext (sLit "because the instance type constructor") <+> quotes (ppr tycon) <+>
- ptext (sLit "was not compiled with -XGenerics")]
-
+{-
badGenericInstanceType :: LHsBinds Name -> SDoc
badGenericInstanceType binds
= vcat [ptext (sLit "Illegal type pattern in the generic bindings"),
]
where
ppr_inst_ty (_,inst) = ppr (simpleInstInfoTy inst)
-
-mixedGenericErr :: Name -> SDoc
-mixedGenericErr op
- = ptext (sLit "Can't mix generic and non-generic equations for class method") <+> quotes (ppr op)
+-}
+badDmPrag :: Id -> Sig Name -> TcM ()
+badDmPrag sel_id prag
+ = addErrTc (ptext (sLit "The") <+> hsSigDoc prag <+> ptext (sLit "for default method")
+ <+> quotes (ppr sel_id)
+ <+> ptext (sLit "lacks an accompanying binding"))
\end{code}
projects / ghc-hetmet.git / blobdiff