Instead, we simply rely on the fact that casts are cheap:
$df :: forall a. C a => C [a]
- {-# INLINE df #} -- NB: INLINE this
+ {-# INLINE df #-} -- NB: INLINE this
$df = /\a. \d. MkC [a] ($cop_list a d)
= $cop_list |> forall a. C a -> (sym (Co:C [a]))
; let { (local_info,
at_tycons_s) = unzip local_info_tycons
; at_idx_tycons = concat at_tycons_s ++ idx_tycons
- ; clas_decls = filter (isClassDecl . unLoc) tycl_decls
- ; implicit_things = concatMap implicitTyThings at_idx_tycons
- ; aux_binds = mkRecSelBinds at_idx_tycons
- }
+ ; implicit_things = concatMap implicitTyConThings at_idx_tycons
+ ; aux_binds = mkRecSelBinds at_idx_tycons }
-- (2) Add the tycons of indexed types and their implicit
-- tythings to the global environment
- ; tcExtendGlobalEnv (at_idx_tycons ++ implicit_things) $ do {
+ ; tcExtendGlobalEnv (map ATyCon at_idx_tycons ++ implicit_things) $ do {
- -- (3) Instances from generic class declarations
- ; generic_inst_info <- getGenericInstances clas_decls
-- Next, construct the instance environment so far, consisting
-- of
-- (a) local instance decls
- -- (b) generic instances
- -- (c) local family instance decls
+ -- (b) local family instance decls
; addInsts local_info $
- addInsts generic_inst_info $
addFamInsts at_idx_tycons $ do {
- -- (4) Compute instances from "deriving" clauses;
+ -- (3) Compute instances from "deriving" clauses;
-- This stuff computes a context for the derived instance
-- decl, so it needs to know about all the instances possible
-- NB: class instance declarations can contain derivings as
-- part of associated data type declarations
- failIfErrsM -- If the addInsts stuff gave any errors, don't
- -- try the deriving stuff, becuase that may give
- -- more errors still
- ; (deriv_inst_info, deriv_binds, deriv_dus)
+ failIfErrsM -- If the addInsts stuff gave any errors, don't
+ -- try the deriving stuff, because that may give
+ -- more errors still
+ ; (deriv_inst_info, deriv_binds, deriv_dus, deriv_tys, deriv_ty_insts)
<- tcDeriving tycl_decls inst_decls deriv_decls
- ; gbl_env <- addInsts deriv_inst_info getGblEnv
+
+ -- Extend the global environment also with the generated datatypes for
+ -- the generic representation
+ ; let all_tycons = map ATyCon (deriv_tys ++ deriv_ty_insts)
+ ; gbl_env <- tcExtendGlobalEnv all_tycons $
+ tcExtendGlobalEnv (concatMap implicitTyThings all_tycons) $
+ addFamInsts deriv_ty_insts $
+ addInsts deriv_inst_info getGblEnv
; return ( addTcgDUs gbl_env deriv_dus,
- generic_inst_info ++ deriv_inst_info ++ local_info,
+ deriv_inst_info ++ local_info,
aux_binds `plusHsValBinds` deriv_binds)
}}}
addInsts infos thing_inside
= tcExtendLocalInstEnv (map iSpec infos) thing_inside
-addFamInsts :: [TyThing] -> TcM a -> TcM a
+addFamInsts :: [TyCon] -> TcM a -> TcM a
addFamInsts tycons thing_inside
- = tcExtendLocalFamInstEnv (map mkLocalFamInstTyThing tycons) thing_inside
- where
- mkLocalFamInstTyThing (ATyCon tycon) = mkLocalFamInst tycon
- mkLocalFamInstTyThing tything = pprPanic "TcInstDcls.addFamInsts"
- (ppr tything)
+ = tcExtendLocalFamInstEnv (map mkLocalFamInst tycons) thing_inside
\end{code}
\begin{code}
tcLocalInstDecl1 :: LInstDecl Name
- -> TcM (InstInfo Name, [TyThing])
+ -> TcM (InstInfo Name, [TyCon])
-- A source-file instance declaration
-- Type-check all the stuff before the "where"
--
checkValidAndMissingATs :: Class
-> ([TyVar], [TcType]) -- instance types
-> [(LTyClDecl Name, -- source form of AT
- TyThing)] -- Core form of AT
+ TyCon)] -- Core form of AT
-> TcM ()
checkValidAndMissingATs clas inst_tys ats
= do { -- Issue a warning for each class AT that is not defined in this
; mapM_ (checkIndexes clas inst_tys) ats
}
- checkIndexes clas inst_tys (hsAT, ATyCon tycon)
+ checkIndexes clas inst_tys (hsAT, tycon)
-- !!!TODO: check that this does the Right Thing for indexed synonyms, too!
= checkIndexes' clas inst_tys hsAT
(tyConTyVars tycon,
snd . fromJust . tyConFamInst_maybe $ tycon)
- checkIndexes _ _ _ = panic "checkIndexes"
checkIndexes' clas (instTvs, instTys) hsAT (atTvs, atTys)
= let atName = tcdName . unLoc $ hsAT
GADTs).
\begin{code}
-tcFamInstDecl :: TopLevelFlag -> LTyClDecl Name -> TcM TyThing
+tcFamInstDecl :: TopLevelFlag -> LTyClDecl Name -> TcM TyCon
tcFamInstDecl top_lvl (L loc decl)
= -- Prime error recovery, set source location
setSrcSpan loc $
; when (isTopLevel top_lvl && isAssocFamily tc)
(addErr $ assocInClassErr (tcdName decl))
- ; return (ATyCon tc) }
+ ; return tc }
isAssocFamily :: TyCon -> Bool -- Is an assocaited type
isAssocFamily tycon
NewType -> ASSERT( not (null data_cons) )
mkNewTyConRhs rep_tc_name rep_tycon (head data_cons)
; buildAlgTyCon rep_tc_name t_tvs stupid_theta tc_rhs Recursive
- False h98_syntax NoParentTyCon (Just (fam_tycon, t_typats))
+ h98_syntax NoParentTyCon (Just (fam_tycon, t_typats))
-- We always assume that indexed types are recursive. Why?
-- (1) Due to their open nature, we can never be sure that a
-- further instance might not introduce a new recursive
addErrCtxt (instDeclCtxt2 (idType dfun_id)) $
do { -- Instantiate the instance decl with skolem constants
; (inst_tyvars, dfun_theta, inst_head) <- tcSkolDFunType (idType dfun_id)
+ -- We instantiate the dfun_id with superSkolems.
+ -- See Note [Subtle interaction of recursion and overlap]
+ -- and Note [Binding when looking up instances]
; let (clas, inst_tys) = tcSplitDFunHead inst_head
(class_tyvars, sc_theta, _, op_items) = classBigSig clas
sc_theta' = substTheta (zipOpenTvSubst class_tyvars inst_tys) sc_theta
listToBag meth_binds)
}
where
- skol_info = InstSkol -- See Note [Subtle interaction of recursion and overlap]
+ skol_info = InstSkol
dfun_ty = idType dfun_id
dfun_id = instanceDFunId ispec
loc = getSrcSpan dfun_id
----------------------
tc_default :: Id -> DefMeth -> TcM (TcId, LHsBind Id)
+
+ tc_default sel_id (GenDefMeth dm_name)
+ = do { meth_bind <- mkGenericDefMethBind clas inst_tys sel_id dm_name
+ ; tc_body sel_id False {- Not generated code? -} meth_bind }
+{-
tc_default sel_id GenDefMeth -- Derivable type classes stuff
= do { meth_bind <- mkGenericDefMethBind clas inst_tys sel_id
; tc_body sel_id False {- Not generated code? -} meth_bind }
-
+-}
tc_default sel_id NoDefMeth -- No default method at all
= do { warnMissingMethod sel_id
; (meth_id, _) <- mkMethIds clas tyvars dfun_ev_vars
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