#include "HsVersions.h"
-import HsSyn ( HsDecl(..), InstDecl(..), HsType(..),
+import HsSyn ( HsDecl(..), InstDecl(..),
HsBinds(..), MonoBinds(..), GRHSsAndBinds(..), GRHS(..),
- HsExpr(..), InPat(..), HsLit(..),
+ HsExpr(..), InPat(..), HsLit(..), Sig(..),
unguardedRHS,
collectMonoBinders, andMonoBinds
)
+import HsBinds ( sigsForMe )
import RnHsSyn ( RenamedHsBinds, RenamedMonoBinds,
- RenamedInstDecl, RenamedFixityDecl, RenamedHsExpr,
- RenamedSig, RenamedSpecInstSig, RenamedHsDecl
+ RenamedInstDecl, RenamedHsExpr,
+ RenamedSig, RenamedHsDecl
+ )
+import TcHsSyn ( TcMonoBinds, TcIdOcc(..), TcIdBndr,
+ maybeBoxedPrimType, tcIdType
)
-import TcHsSyn ( TcHsBinds,
- TcMonoBinds, TcExpr, TcIdOcc(..), TcIdBndr,
- tcIdType, maybeBoxedPrimType,
- mkHsTyLam, mkHsTyApp,
- mkHsDictLam, mkHsDictApp )
-import TcBinds ( tcPragmaSigs, sigThetaCtxt )
+import TcBinds ( tcPragmaSigs )
import TcClassDcl ( tcMethodBind, badMethodErr )
import TcMonad
import RnMonad ( RnNameSupply )
-import Inst ( Inst, InstOrigin(..), InstanceMapper,
- instToId, newDicts, newMethod, LIE, emptyLIE, plusLIE )
-import PragmaInfo ( PragmaInfo(..) )
+import Inst ( Inst, InstOrigin(..),
+ newDicts, LIE, emptyLIE, plusLIE, plusLIEs )
import TcDeriv ( tcDeriving )
-import TcEnv ( tcLookupClass, newLocalId, tcGetGlobalTyVars,
- tcExtendGlobalValEnv, tcAddImportedIdInfo
- )
-import TcInstUtil ( InstInfo(..), mkInstanceRelatedIds, buildInstanceEnvs, classDataCon )
+import TcEnv ( tcExtendGlobalValEnv, tcAddImportedIdInfo )
+import TcInstUtil ( InstInfo(..), mkInstanceRelatedIds, classDataCon )
import TcKind ( TcKind, unifyKind )
-import TcMatches ( tcMatchesFun )
-import TcMonoType ( tcTyVarScope, tcContext, tcHsTypeKind, tcHsType )
+import TcMonoType ( tcHsType )
import TcSimplify ( tcSimplifyAndCheck )
import TcType ( TcType, TcTyVar, TcTyVarSet,
- zonkSigTyVar,
- tcInstSigTyVars, tcInstType, tcInstSigTcType,
- tcInstTheta, tcInstTcType
+ zonkSigTyVar, tcInstSigTyVars, tcInstType, tcInstTheta
)
-import Unify ( unifyTauTy, unifyTauTyLists )
-
import Bag ( emptyBag, unitBag, unionBags, unionManyBags,
- concatBag, foldBag, bagToList, listToBag,
- Bag
+ foldBag, bagToList, Bag
)
-import CmdLineOpts ( opt_GlasgowExts,
- opt_SpecialiseOverloaded, opt_WarnMissingMethods
- )
-import Class ( classBigSig, classTyCon, Class )
-import Id ( idType, replacePragmaInfo,
- isNullaryDataCon, dataConArgTys, Id )
-import ListSetOps ( minusList )
-import Maybes ( maybeToBool, expectJust, seqMaybe, catMaybes )
-import Name ( nameOccName, getSrcLoc, mkLocalName,
+import CmdLineOpts ( opt_GlasgowExts, opt_WarnMissingMethods )
+import Class ( classBigSig, Class )
+import Id ( isNullaryDataCon, dataConArgTys, replaceIdInfo, idName, Id )
+import Maybes ( maybeToBool, seqMaybe, catMaybes )
+import Name ( nameOccName, mkLocalName,
isLocallyDefined, Module,
NamedThing(..)
)
-import PrelVals ( nO_METHOD_BINDING_ERROR_ID )
-import PprType ( pprParendGenType, pprConstraint )
+import PrelVals ( nO_METHOD_BINDING_ERROR_ID, eRROR_ID )
+import PprType ( pprParendType, pprConstraint )
import SrcLoc ( SrcLoc, noSrcLoc )
-import TyCon ( tyConDataCons, isSynTyCon, isDataTyCon, tyConDerivings )
-import Type ( Type, ThetaType, mkTyVarTys, isUnpointedType,
- splitSigmaTy, splitAppTys, isTyVarTy, matchTy, mkSigmaTy,
- splitTyConApp_maybe, getTyVar, splitDictTy_maybe,
- splitAlgTyConApp_maybe, splitRhoTy, isSynTy,
+import TyCon ( isSynTyCon, isDataTyCon, tyConDerivings )
+import Type ( Type, ThetaType, isUnpointedType,
+ splitSigmaTy, isTyVarTy, mkSigmaTy,
+ splitTyConApp_maybe, splitDictTy_maybe,
+ splitAlgTyConApp_maybe, splitRhoTy,
tyVarsOfTypes
)
import TyVar ( zipTyVarEnv, mkTyVarSet, tyVarSetToList, TyVar )
import TysPrim ( byteArrayPrimTyCon, mutableByteArrayPrimTyCon )
import TysWiredIn ( stringTy )
import Unique ( Unique, cCallableClassKey, cReturnableClassKey, Uniquable(..) )
-import Util ( zipEqual, removeDups )
import Outputable
\end{code}
tcInstTheta tenv inst_decl_theta `thenNF_Tc` \ inst_decl_theta' ->
-- Instantiate the super-class context with inst_tys
-
tcInstTheta (zipTyVarEnv class_tyvars inst_tys') sc_theta `thenNF_Tc` \ sc_theta' ->
-- Create dictionary Ids from the specified instance contexts.
newDicts origin inst_decl_theta' `thenNF_Tc` \ (inst_decl_dicts, _) ->
newDicts origin [(clas,inst_tys')] `thenNF_Tc` \ (this_dict, [this_dict_id]) ->
- -- Now process any INLINE or SPECIALIZE pragmas for the methods
- -- ...[NB May 97; all ignored except INLINE]
- tcPragmaSigs uprags `thenTc` \ (prag_fn, spec_binds, spec_lie) ->
-
-- Check that all the method bindings come from this class
let
check_from_this_class (bndr, loc)
tcExtendGlobalValEnv (catMaybes defm_ids) (
-- Default-method Ids may be mentioned in synthesised RHSs
- mapAndUnzip3Tc (tcInstMethodBind clas inst_tys' inst_tyvars' monobinds)
+ mapAndUnzip3Tc (tcInstMethodBind clas inst_tys' inst_tyvars' monobinds uprags)
(op_sel_ids `zip` defm_ids)
) `thenTc` \ (method_binds_s, insts_needed_s, meth_lies_w_ids) ->
+ -- Deal with SPECIALISE instance pragmas
+ let
+ dfun_prags = [Sig (idName dfun_id) ty loc | SpecInstSig ty loc <- uprags]
+ in
+ tcExtendGlobalValEnv [dfun_id] (
+ tcPragmaSigs dfun_prags
+ ) `thenTc` \ (prag_info_fn, prag_binds, prag_lie) ->
+
-- Check the overloading constraints of the methods and superclasses
mapNF_Tc zonkSigTyVar inst_tyvars' `thenNF_Tc` \ zonked_inst_tyvars ->
dfun_arg_dicts `plusLIE`
sc_dicts `plusLIE`
unionManyBags meth_lies
- in
- tcAddErrCtxt superClassCtxt $
- tcAddErrCtxtM (sigThetaCtxt sc_dicts) $
-
-
- -- Deal with the LIE arising from the method bindings
- tcSimplifyAndCheck (text "inst decl1a")
- inst_tyvars_set -- Local tyvars
- avail_insts
- (unionManyBags insts_needed_s) -- Need to get defns for all these
- `thenTc` \ (const_lie1, op_binds) ->
- -- Deal with the super-class bindings
- -- Ignore errors because they come from the *next* tcSimplify
- discardErrsTc (
- tcSimplifyAndCheck (text "inst decl1b")
- inst_tyvars_set
- dfun_arg_dicts -- NB! Don't include this_dict here, else the sc_dicts
- -- get bound by just selecting from this_dict!!
- sc_dicts
- ) `thenTc` \ (const_lie2, sc_binds) ->
-
+ methods_lie = plusLIEs insts_needed_s
+ in
-- Check that we *could* construct the superclass dictionaries,
-- even though we are *actually* going to pass the superclass dicts in;
-- the check ensures that the caller will never have a problem building
-- them.
- tcSimplifyAndCheck (text "inst decl1c")
+ tcAddErrCtxt superClassCtxt (
+ tcSimplifyAndCheck
+ (ptext SLIT("instance declaration context"))
inst_tyvars_set -- Local tyvars
inst_decl_dicts -- The instance dictionaries available
sc_dicts -- The superclass dicationaries reqd
- `thenTc_`
- -- Ignore the result; we're only doing
+ ) `thenTc_`
+ -- Ignore the result; we're only doing
-- this to make sure it can be done.
+ -- Ditto method bindings
+ tcAddErrCtxt methodCtxt (
+ tcSimplifyAndCheck
+ (ptext SLIT("instance declaration context"))
+ inst_tyvars_set -- Local tyvars
+ avail_insts
+ methods_lie
+ ) `thenTc_`
+
+ -- Now do the simplification again, this time to get the
+ -- bindings; this time we use an enhanced "avails"
+ -- Ignore errors because they come from the *previous* tcSimplifys
+ discardErrsTc (
+ tcSimplifyAndCheck
+ (ptext SLIT("instance declaration context"))
+ inst_tyvars_set
+ dfun_arg_dicts -- NB! Don't include this_dict here, else the sc_dicts
+ -- get bound by just selecting from this_dict!!
+ (sc_dicts `plusLIE` methods_lie `plusLIE` prag_lie)
+ ) `thenTc` \ (const_lie, lie_binds) ->
+
+
-- Create the result bindings
let
- const_lie = const_lie1 `plusLIE` const_lie2
- lie_binds = op_binds `AndMonoBinds` sc_binds
-
- dict_constr = classDataCon clas
-
- con_app = foldl HsApp (TyApp (HsVar (RealId dict_constr)) inst_tys')
- (map HsVar (sc_dict_ids ++ meth_ids))
+ dict_constr = classDataCon clas
+ scs_and_meths = sc_dict_ids ++ meth_ids
+
+ dict_rhs
+ | null scs_and_meths
+ = -- Blatant special case for CCallable, CReturnable
+ -- If the dictionary is empty then we should never
+ -- select anything from it, so we make its RHS just
+ -- emit an error message. This in turn means that we don't
+ -- mention the constructor, which doesn't exist for CCallable, CReturnable
+ -- Hardly beautiful, but only three extra lines.
+ HsApp (TyApp (HsVar (RealId eRROR_ID)) [tcIdType this_dict_id])
+ (HsLitOut (HsString msg) stringTy)
+
+ | otherwise -- The common case
+ = foldl HsApp (TyApp (HsVar (RealId dict_constr)) inst_tys')
+ (map HsVar (sc_dict_ids ++ meth_ids))
-- We don't produce a binding for the dict_constr; instead we
-- rely on the simplifier to unfold this saturated application
+ where
+ msg = _PK_ ("Compiler error: bad dictionary " ++ showSDoc (ppr clas))
- dict_bind = VarMonoBind this_dict_id con_app
+ dict_bind = VarMonoBind this_dict_id dict_rhs
method_binds = andMonoBinds method_binds_s
+ final_dfun_id = replaceIdInfo dfun_id (prag_info_fn (idName dfun_id))
+ -- Pretty truesome
main_bind
= AbsBinds
zonked_inst_tyvars
dfun_arg_dicts_ids
- [(inst_tyvars', RealId dfun_id, this_dict_id)]
+ [(inst_tyvars', RealId final_dfun_id, this_dict_id)]
(lie_binds `AndMonoBinds`
method_binds `AndMonoBinds`
+ prag_binds `AndMonoBinds`
dict_bind)
in
- returnTc (const_lie `plusLIE` spec_lie,
- main_bind `AndMonoBinds` spec_binds)
+ returnTc (const_lie,
+ main_bind `AndMonoBinds` prag_binds)
\end{code}
-> [TcType s] -- Instance types
-> [TcTyVar s] -- and their free (sig) tyvars
-> RenamedMonoBinds -- Method binding
+ -> [RenamedSig] -- Pragmas
-> (Id, Maybe Id) -- Selector id and default-method id
-> TcM s (TcMonoBinds s, LIE s, (LIE s, TcIdOcc s))
-tcInstMethodBind clas inst_tys inst_tyvars meth_binds (sel_id, maybe_dm_id)
+tcInstMethodBind clas inst_tys inst_tyvars meth_binds prags (sel_id, maybe_dm_id)
= tcGetSrcLoc `thenNF_Tc` \ loc ->
tcGetUnique `thenNF_Tc` \ uniq ->
let
- meth_occ = getOccName sel_id
+ sel_name = idName sel_id
+ meth_occ = getOccName sel_name
default_meth_name = mkLocalName uniq meth_occ loc
maybe_meth_bind = find meth_occ meth_binds
the_meth_bind = case maybe_meth_bind of
Just stuff -> stuff
Nothing -> mk_default_bind default_meth_name loc
+ meth_prags = sigsForMe (== sel_name) prags
in
-- Warn if no method binding, only if -fwarn-missing-methods
- warnTc (opt_WarnMissingMethods &&
+ warnTc (opt_WarnMissingMethods &&
not (maybeToBool maybe_meth_bind) &&
not (maybeToBool maybe_dm_id))
(omittedMethodWarn sel_id clas) `thenNF_Tc_`
-- Typecheck the method binding
- tcMethodBind clas origin inst_tys inst_tyvars sel_id the_meth_bind
+ tcMethodBind clas origin inst_tys inst_tyvars sel_id the_meth_bind meth_prags
where
origin = InstanceDeclOrigin -- Poor
(HsLit (HsString (_PK_ (error_msg loc))))
error_msg loc = showSDoc (hcat [ppr loc, text "|", ppr sel_id ])
-
\end{code}
%************************************************************************
%* *
-\subsection{Type-checking specialise instance pragmas}
+\subsection{Checking for a decent instance type}
%* *
%************************************************************************
-\begin{code}
-{- LATER
-tcSpecInstSigs :: E -> CE -> TCE
- -> Bag InstInfo -- inst decls seen (declared and derived)
- -> [RenamedSpecInstSig] -- specialise instance upragmas
- -> TcM (Bag InstInfo) -- new, overlapped, inst decls
-
-tcSpecInstSigs e ce tce inst_infos []
- = returnTc emptyBag
-
-tcSpecInstSigs e ce tce inst_infos sigs
- = buildInstanceEnvs inst_infos `thenTc` \ inst_mapper ->
- tc_inst_spec_sigs inst_mapper sigs `thenNF_Tc` \ spec_inst_infos ->
- returnTc spec_inst_infos
- where
- tc_inst_spec_sigs inst_mapper []
- = returnNF_Tc emptyBag
- tc_inst_spec_sigs inst_mapper (sig:sigs)
- = tcSpecInstSig e ce tce inst_infos inst_mapper sig `thenNF_Tc` \ info_sig ->
- tc_inst_spec_sigs inst_mapper sigs `thenNF_Tc` \ info_sigs ->
- returnNF_Tc (info_sig `unionBags` info_sigs)
-
-tcSpecInstSig :: E -> CE -> TCE
- -> Bag InstInfo
- -> InstanceMapper
- -> RenamedSpecInstSig
- -> NF_TcM (Bag InstInfo)
-
-tcSpecInstSig e ce tce inst_infos inst_mapper (SpecInstSig class_name ty src_loc)
- = recoverTc emptyBag (
- tcAddSrcLoc src_loc (
- let
- clas = lookupCE ce class_name -- Renamer ensures this can't fail
-
- -- Make some new type variables, named as in the specialised instance type
- ty_names = extractHsTyNames ???is_tyvarish_name??? ty
- (tmpl_e,inst_tmpls,inst_tmpl_tys) = mkTVE ty_names
- in
- babyTcMtoTcM (tcInstanceType ce tce tmpl_e True src_loc ty)
- `thenTc` \ inst_ty ->
- let
- maybe_tycon = case splitAlgTyConApp_maybe inst_ty of
- Just (tc,_,_) -> Just tc
- Nothing -> Nothing
-
- maybe_unspec_inst = lookup_unspec_inst clas maybe_tycon inst_infos
- in
- -- Check that we have a local instance declaration to specialise
- checkMaybeTc maybe_unspec_inst
- (specInstUnspecInstNotFoundErr clas inst_ty src_loc) `thenTc_`
-
- -- Create tvs to substitute for tmpls while simplifying the context
- copyTyVars inst_tmpls `thenNF_Tc` \ (tv_e, inst_tvs, inst_tv_tys) ->
- let
- Just (InstInfo _ unspec_tyvars unspec_inst_ty unspec_theta
- _ _ binds _ uprag) = maybe_unspec_inst
-
- subst = case matchTy unspec_inst_ty inst_ty of
- Just subst -> subst
- Nothing -> panic "tcSpecInstSig:matchTy"
-
- subst_theta = instantiateThetaTy subst unspec_theta
- subst_tv_theta = instantiateThetaTy tv_e subst_theta
-
- mk_spec_origin clas ty
- = InstanceSpecOrigin inst_mapper clas ty src_loc
- -- I'm VERY SUSPICIOUS ABOUT THIS
- -- the inst-mapper is in a knot at this point so it's no good
- -- looking at it in tcSimplify...
- in
- tcSimplifyThetas mk_spec_origin subst_tv_theta
- `thenTc` \ simpl_tv_theta ->
- let
- simpl_theta = [ (clas, tv_to_tmpl tv) | (clas, tv) <- simpl_tv_theta ]
-
- tv_tmpl_map = zipEqual "tcSpecInstSig" inst_tv_tys inst_tmpl_tys
- tv_to_tmpl tv = assoc "tcSpecInstSig" tv_tmpl_map tv
- in
- mkInstanceRelatedIds clas inst_tmpls inst_ty simpl_theta uprag
- `thenNF_Tc` \ (dfun_id, dfun_theta, const_meth_ids) ->
-
- getSwitchCheckerTc `thenNF_Tc` \ sw_chkr ->
- (if sw_chkr SpecialiseTrace then
- pprTrace "Specialised Instance: "
- (vcat [hsep [if null simpl_theta then empty else ppr simpl_theta,
- if null simpl_theta then empty else ptext SLIT("=>"),
- ppr clas,
- pprParendGenType inst_ty],
- hsep [ptext SLIT(" derived from:"),
- if null unspec_theta then empty else ppr unspec_theta,
- if null unspec_theta then empty else ptext SLIT("=>"),
- ppr clas,
- pprParendGenType unspec_inst_ty]])
- else id) (
-
- returnTc (unitBag (InstInfo clas inst_tmpls inst_ty simpl_theta
- dfun_theta dfun_id
- binds src_loc uprag))
- )))
-
-
-lookup_unspec_inst clas maybe_tycon inst_infos
- = case filter (match_info match_inst_ty) (bagToList inst_infos) of
- [] -> Nothing
- (info:_) -> Just info
- where
- match_info match_ty (InstInfo inst_clas _ inst_ty _ _ _ _ _ from_here _ _ _)
- = from_here && clas == inst_clas &&
- match_ty inst_ty && is_plain_instance inst_ty
-
- match_inst_ty = case maybe_tycon of
- Just tycon -> match_tycon tycon
- Nothing -> match_fun
-
- match_tycon tycon inst_ty = case (splitAlgTyConApp_maybe inst_ty) of
- Just (inst_tc,_,_) -> tycon == inst_tc
- Nothing -> False
-
- match_fun inst_ty = isFunType inst_ty
-
-
-is_plain_instance inst_ty
- = case (splitAlgTyConApp_maybe inst_ty) of
- Just (_,tys,_) -> all isTyVarTemplateTy tys
- Nothing -> case maybeUnpackFunTy inst_ty of
- Just (arg, res) -> isTyVarTemplateTy arg && isTyVarTemplateTy res
- Nothing -> error "TcInstDecls:is_plain_instance"
--}
-\end{code}
-
-
-Checking for a decent instance type
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@scrutiniseInstanceType@ checks the type {\em and} its syntactic constraints:
it must normally look like: @instance Foo (Tycon a b c ...) ...@
--
-- We flag this separately to give a more precise error msg.
--
- (uniqueOf clas == cCallableClassKey && not constructors_visible) ||
- (uniqueOf clas == cReturnableClassKey && not constructors_visible)
+ (uniqueOf clas == cCallableClassKey || uniqueOf clas == cReturnableClassKey)
+ && is_alg_tycon_app && not constructors_visible
= failWithTc (invisibleDataConPrimCCallErr clas first_inst_tau)
| -- CCALL CHECK (b)
-- DERIVING CHECK
-- It is obviously illegal to have an explicit instance
-- for something that we are also planning to `derive'
- | clas `elem` (tyConDerivings inst_tycon)
+ | maybeToBool alg_tycon_app_maybe && clas `elem` (tyConDerivings alg_tycon)
= failWithTc (derivingWhenInstanceExistsErr clas first_inst_tau)
-- Kind check will have ensured inst_taus is of length 1
- -- ALL TYPE VARIABLES => bad
- | all isTyVarTy inst_taus
- = failWithTc (instTypeErr clas inst_taus (text "all the instance types are type variables"))
-
-- WITH HASKELL 1.4, MUST HAVE C (T a b c)
- | not opt_GlasgowExts
+ | not opt_GlasgowExts
&& not (length inst_taus == 1 &&
- maybeToBool tyconapp_maybe &&
- not (isSynTyCon inst_tycon) &&
- all isTyVarTy arg_tys &&
+ maybeToBool maybe_tycon_app && -- Yes, there's a type constuctor
+ not (isSynTyCon tycon) && -- ...but not a synonym
+ all isTyVarTy arg_tys && -- Applied to type variables
length (tyVarSetToList (tyVarsOfTypes arg_tys)) == length arg_tys
-- This last condition checks that all the type variables are distinct
)
= returnTc ()
where
- tyconapp_maybe = splitTyConApp_maybe first_inst_tau
- Just (inst_tycon, arg_tys) = tyconapp_maybe
(first_inst_tau : _) = inst_taus
- constructors_visible =
- case splitAlgTyConApp_maybe first_inst_tau of
- Just (_,_,[]) -> False
- everything_else -> True
+ -- Stuff for algebraic or -> type
+ maybe_tycon_app = splitTyConApp_maybe first_inst_tau
+ Just (tycon, arg_tys) = maybe_tycon_app
+
+ -- Stuff for an *algebraic* data type
+ alg_tycon_app_maybe = splitAlgTyConApp_maybe first_inst_tau
+ -- The "Alg" part looks through synonyms
+ is_alg_tycon_app = maybeToBool alg_tycon_app_maybe
+ Just (alg_tycon, _, data_cons) = alg_tycon_app_maybe
+
+ constructors_visible = not (null data_cons)
+
-- These conditions come directly from what the DsCCall is capable of.
-- Totally grotesque. Green card should solve this.
nest 4 (parens msg)
]
-instBndrErr bndr clas
- = hsep [ptext SLIT("Class"), quotes (ppr clas), ptext SLIT("does not have a method"), quotes (ppr bndr)]
-
derivingWhenInstanceExistsErr clas tycon
= hang (hsep [ptext SLIT("Deriving class"),
quotes (ppr clas),
ppr inst_ty])
omittedMethodWarn sel_id clas
- = sep [ptext SLIT("Warning: no explicit method nor default method for") <+> quotes (ppr sel_id),
+ = sep [ptext SLIT("No explicit method nor default method for") <+> quotes (ppr sel_id),
ptext SLIT("in an instance declaration for") <+> quotes (ppr clas)]
{-
4 (hsep [text "(Try either importing", ppr inst_ty,
text "non-abstractly or compile using -fno-prune-tydecls ..)"])
-instMethodNotInClassErr occ clas
- = hang (ptext SLIT("Instance mentions a method not in the class"))
- 4 (hsep [ptext SLIT("class") <+> quotes (ppr clas),
- ptext SLIT("method") <+> quotes (ppr occ)])
-
-patMonoBindsCtxt pbind
- = hang (ptext SLIT("In a pattern binding:"))
- 4 (ppr pbind)
-
-methodSigCtxt name ty
- = hang (hsep [ptext SLIT("When matching the definition of class method"),
- quotes (ppr name), ptext SLIT("to its signature :") ])
- 4 (ppr ty)
-
-superClassCtxt = ptext SLIT("From the superclasses of the instance declaration")
+methodCtxt = ptext SLIT("When checking the methods of an instance declaration")
+superClassCtxt = ptext SLIT("When checking the superclasses of an instance declaration")
\end{code}
projects / ghc-hetmet.git / blobdiff