#include "HsVersions.h"
-import CmdLineOpts ( opt_GlasgowExts, opt_AllowUndecidableInstances, opt_D_dump_deriv )
+import CmdLineOpts ( DynFlag(..), dopt )
-import HsSyn ( HsDecl(..), InstDecl(..), TyClDecl(..),
- MonoBinds(..), HsExpr(..), HsLit(..), Sig(..),
+import HsSyn ( HsDecl(..), InstDecl(..), TyClDecl(..),
+ MonoBinds(..), HsExpr(..), HsLit(..), Sig(..),
andMonoBindList, collectMonoBinders, isClassDecl
)
-import HsTypes ( HsType (..), HsTyVarBndr(..), toHsTyVar )
-import HsPat ( InPat (..) )
-import HsMatches ( Match (..) )
-import RnHsSyn ( RenamedHsBinds, RenamedInstDecl, RenamedHsDecl, extractHsTyVars )
+import RnHsSyn ( RenamedHsBinds, RenamedInstDecl, RenamedHsDecl, RenamedMonoBinds,
+ RenamedTyClDecl, RenamedHsType,
+ extractHsTyVars, maybeGenericMatch
+ )
import TcHsSyn ( TcMonoBinds, mkHsConApp )
import TcBinds ( tcSpecSigs )
import TcClassDcl ( tcMethodBind, badMethodErr )
import TcMonad
-import RnMonad ( RnNameSupply, FixityEnv )
import Inst ( InstOrigin(..),
newDicts, newClassDicts,
LIE, emptyLIE, plusLIE, plusLIEs )
import TcDeriv ( tcDeriving )
-import TcEnv ( ValueEnv, tcExtendGlobalValEnv,
- tcExtendTyVarEnvForMeths, TyThing (..),
+import TcEnv ( TcEnv, tcExtendGlobalValEnv,
+ tcExtendTyVarEnvForMeths,
tcAddImportedIdInfo, tcInstId, tcLookupClass,
+ InstInfo(..), pprInstInfo, simpleInstInfoTyCon, simpleInstInfoTy,
newDFunName, tcExtendTyVarEnv
)
-import TcInstUtil ( InstInfo(..), pprInstInfo, classDataCon, simpleInstInfoTyCon, simpleInstInfoTy )
-import TcMonoType ( tcTyVars, tcHsSigType, tcHsType, kcHsSigType )
+import InstEnv ( InstEnv, extendInstEnv )
+import TcMonoType ( tcTyVars, tcHsSigType, kcHsSigType )
import TcSimplify ( tcSimplifyAndCheck )
import TcType ( zonkTcSigTyVars )
-
-import Bag ( emptyBag, unitBag, unionBags, unionManyBags,
- foldBag, Bag, listToBag
+import HscTypes ( HomeSymbolTable, DFunId,
+ ModDetails(..), PackageInstEnv, PersistentRenamerState
)
+
+import Bag ( unionManyBags )
+import DataCon ( classDataCon )
import Class ( Class, DefMeth(..), classBigSig )
import Var ( idName, idType )
-import Maybes ( maybeToBool, expectJust )
+import Maybes ( maybeToBool )
import MkId ( mkDictFunId )
import Generics ( validGenericInstanceType )
-import Module ( Module )
-import Name ( isLocallyDefined )
+import Module ( Module, foldModuleEnv )
+import Name ( getSrcLoc )
import NameSet ( emptyNameSet, nameSetToList )
import PrelInfo ( eRROR_ID )
import PprType ( pprConstraint, pprPred )
-import TyCon ( isSynTyCon, tyConDerivings )
-import Type ( mkTyVarTys, splitSigmaTy, isTyVarTy,
- splitTyConApp_maybe, splitDictTy_maybe,
- splitAlgTyConApp_maybe, classesToPreds, classesOfPreds,
- unUsgTy, tyVarsOfTypes, mkClassPred, mkTyVarTy,
+import TyCon ( TyCon, isSynTyCon )
+import Type ( splitDFunTy, isTyVarTy,
+ splitTyConApp_maybe, splitDictTy,
+ splitForAllTys,
+ tyVarsOfTypes, mkClassPred, mkTyVarTy,
getClassTys_maybe
)
-import Subst ( mkTopTyVarSubst, substClasses, substTheta )
+import Subst ( mkTopTyVarSubst, substClasses )
import VarSet ( mkVarSet, varSetElems )
import TysWiredIn ( genericTyCons, isFFIArgumentTy, isFFIResultTy )
import PrelNames ( cCallableClassKey, cReturnableClassKey, hasKey )
-import Name ( Name, NameEnv, extendNameEnv_C, emptyNameEnv,
- plusNameEnv_C, nameEnvElts )
-import FiniteMap ( mapFM )
+import Name ( Name )
import SrcLoc ( SrcLoc )
-import RnHsSyn -- ( RenamedMonoBinds )
import VarSet ( varSetElems )
-import UniqFM ( mapUFM )
import Unique ( Uniquable(..) )
-import BasicTypes ( NewOrData(..) )
-import ErrUtils ( dumpIfSet )
+import BasicTypes ( NewOrData(..), Fixity )
+import ErrUtils ( dumpIfSet_dyn )
import ListSetOps ( Assoc, emptyAssoc, plusAssoc_C, mapAssoc,
assocElts, extendAssoc_C,
equivClassesByUniq, minusList
)
-import List ( intersect, (\\) )
+import List ( partition )
import Outputable
\end{code}
Gather up the instance declarations from their various sources
\begin{code}
-tcInstDecls1 :: PersistentRenamerState
+tcInstDecls1 :: PackageInstEnv
+ -> PersistentRenamerState
+ -> HomeSymbolTable -- Contains instances
-> TcEnv -- Contains IdInfo for dfun ids
- -> [RenamedHsDecl]
+ -> (Name -> Maybe Fixity) -- for deriving Show and Read
-> Module -- Module for deriving
- -> FixityEnv -- For derivings
- -> RnNameSupply -- For renaming derivings
- -> TcM (Bag InstInfo,
- RenamedHsBinds)
-
-tcInstDecls1 prs unf_env decls mod
- = -- (1) Do the ordinary instance declarations
- mapNF_Tc (tcInstDecl1 mod unf_env)
- [inst_decl | InstD inst_decl <- decls] `thenNF_Tc` \ inst_info_bags ->
- let
- decl_inst_info = unionManyBags inst_info_bags
- in
- -- (2) Instances from "deriving" clauses; note that we only do derivings
- -- for things in this module; we ignore deriving decls from
- -- interfaces!
- tcDeriving prs mod decl_inst_info `thenTc` \ (deriv_inst_info, deriv_binds) ->
+ -> [RenamedHsDecl]
+ -> TcM (PackageInstEnv, InstEnv, [InstInfo], RenamedHsBinds)
- -- (3) Instances from generic class declarations
- mapTc (getGenericInstances mod)
- [cl_decl | TyClD cl_decl <- decls, isClassDecl cl_decl] `thenTc` \ cls_inst_info ->
+tcInstDecls1 inst_env0 prs hst unf_env get_fixity mod decls
+ = let
+ inst_decls = [inst_decl | InstD inst_decl <- decls]
+ tycl_decls = [decl | TyClD decl <- decls]
+ clas_decls = filter isClassDecl tycl_decls
+ in
+ -- (1) Do the ordinary instance declarations
+ mapNF_Tc (tcInstDecl1 unf_env) inst_decls `thenNF_Tc` \ inst_infos ->
+
+ -- (2) Instances from generic class declarations
+ getGenericInstances clas_decls `thenTc` \ generic_inst_info ->
+
+ -- Next, construct the instance environment so far, consisting of
+ -- a) cached non-home-package InstEnv (gotten from pcs) pcs_insts pcs
+ -- b) imported instance decls (not in the home package) inst_env1
+ -- c) other modules in this package (gotten from hst) inst_env2
+ -- d) local instance decls inst_env3
+ -- e) generic instances inst_env4
+ -- The result of (b) replaces the cached InstEnv in the PCS
+ let
+ (local_inst_info, imported_inst_info) = partition iLocal (concat inst_infos)
+ imported_dfuns = map (tcAddImportedIdInfo unf_env . iDFunId)
+ imported_inst_info
+ hst_dfuns = foldModuleEnv ((++) . md_insts) [] hst
+ in
+ addInstDFuns inst_env0 imported_dfuns `thenNF_Tc` \ inst_env1 ->
+ addInstDFuns inst_env1 hst_dfuns `thenNF_Tc` \ inst_env2 ->
+ addInstInfos inst_env2 local_inst_info `thenNF_Tc` \ inst_env3 ->
+ addInstInfos inst_env3 generic_inst_info `thenNF_Tc` \ inst_env4 ->
+
+ -- (3) Compute instances from "deriving" clauses;
+ -- note that we only do derivings for things in this module;
+ -- we ignore deriving decls from interfaces!
+ -- This stuff computes a context for the derived instance decl, so it
+ -- needs to know about all the instances possible; hecne inst_env4
+ tcDeriving prs mod inst_env4 get_fixity tycl_decls `thenTc` \ (deriv_inst_info, deriv_binds) ->
+ addInstInfos inst_env4 deriv_inst_info `thenNF_Tc` \ final_inst_env ->
+
+ returnTc (inst_env1,
+ final_inst_env,
+ generic_inst_info ++ deriv_inst_info ++ local_inst_info,
+ deriv_binds)
+
+addInstInfos :: InstEnv -> [InstInfo] -> NF_TcM InstEnv
+addInstInfos inst_env infos = addInstDFuns inst_env (map iDFunId infos)
+
+addInstDFuns :: InstEnv -> [DFunId] -> NF_TcM InstEnv
+addInstDFuns dfuns infos
+ = getDOptsTc `thenTc` \ dflags ->
let
- generic_insts = concat cls_inst_info
- full_inst_info = deriv_inst_info `unionBags`
- unionManyBags inst_info_bags `unionBags`
- (listToBag generic_insts)
+ (inst_env', errs) = extendInstEnv dflags dfuns infos
in
- ioToTc (dumpIfSet opt_D_dump_deriv "Generic instances"
- (vcat (map pprInstInfo generic_insts))) `thenNF_Tc_`
-
- (returnTc (full_inst_info, deriv_binds))
+ addErrsTc errs `thenNF_Tc_`
+ returnTc inst_env'
\end{code}
\begin{code}
-tcInstDecl1 :: Module -> ValueEnv -> RenamedInstDecl -> NF_TcM (Bag InstInfo)
+tcInstDecl1 :: TcEnv -> RenamedInstDecl -> NF_TcM [InstInfo]
-- Deal with a single instance declaration
-tcInstDecl1 mod unf_env (InstDecl poly_ty binds uprags maybe_dfun_name src_loc)
+tcInstDecl1 unf_env (InstDecl poly_ty binds uprags maybe_dfun_name src_loc)
= -- Prime error recovery, set source location
- recoverNF_Tc (returnNF_Tc emptyBag) $
+ recoverNF_Tc (returnNF_Tc []) $
tcAddSrcLoc src_loc $
-- Type-check all the stuff before the "where"
tcHsSigType poly_ty `thenTc` \ poly_ty' ->
let
- (tyvars, theta, dict_ty) = splitSigmaTy poly_ty'
- (clas, inst_tys) = case splitDictTy_maybe dict_ty of
- Just ct -> ct
- Nothing -> pprPanic "tcInstDecl1" (ppr poly_ty)
+ (tyvars, theta, clas, inst_tys) = splitDFunTy poly_ty'
in
(case maybe_dfun_name of
mapNF_Tc scrutiniseInstanceConstraint theta `thenNF_Tc_`
-- Make the dfun id and return it
- newDFunName mod clas inst_tys src_loc `thenNF_Tc` \ dfun_name ->
- returnNF_Tc (mkDictFunId dfun_name clas tyvars inst_tys theta)
+ newDFunName clas inst_tys src_loc `thenNF_Tc` \ dfun_name ->
+ returnNF_Tc (True, dfun_name)
Just dfun_name -> -- An interface-file instance declaration
- -- Make the dfun id and add info from interface file
- let
- dfun_id = mkDictFunId dfun_name clas tyvars inst_tys theta
- in
- returnNF_Tc (tcAddImportedIdInfo unf_env dfun_id)
- ) `thenNF_Tc` \ dfun_id ->
-
- returnTc (unitBag (InstInfo clas tyvars inst_tys theta dfun_id binds src_loc uprags))
+ -- Make the dfun id
+ returnNF_Tc (False, dfun_name)
+ ) `thenNF_Tc` \ (is_local, dfun_name) ->
+
+ let
+ dfun_id = mkDictFunId dfun_name clas tyvars inst_tys theta
+ in
+ returnTc [InstInfo { iLocal = is_local, iDFunId = dfun_id,
+ iBinds = binds, iPrags = uprags }]
\end{code}
\begin{code}
-getGenericInstances :: Module -> RenamedTyClDecl -> TcM [InstInfo]
-getGenericInstances mod decl@(ClassDecl context class_name tyvar_names
- fundeps class_sigs def_methods pragmas
- name_list loc)
+getGenericInstances :: [RenamedTyClDecl] -> TcM [InstInfo]
+getGenericInstances class_decls
+ = mapTc get_generics class_decls `thenTc` \ gen_inst_infos ->
+ let
+ gen_inst_info = concat gen_inst_infos
+ in
+ getDOptsTc `thenTc` \ dflags ->
+ ioToTc (dumpIfSet_dyn dflags Opt_D_dump_deriv "Generic instances"
+ (vcat (map pprInstInfo gen_inst_info)))
+ `thenNF_Tc_`
+ returnTc gen_inst_info
+
+get_generics decl@(ClassDecl {tcdMeths = Nothing})
+ = returnTc [] -- Imported class decls
+
+get_generics decl@(ClassDecl {tcdName = class_name, tcdMeths = Just def_methods, tcdLoc = loc})
| null groups
- = returnTc [] -- The comon case
+ = returnTc [] -- The comon case: no generic default methods
- | otherwise
+ | otherwise -- A local class decl with generic default methods
= recoverNF_Tc (returnNF_Tc []) $
tcAddDeclCtxt decl $
tcLookupClass class_name `thenTc` \ clas ->
-- Make an InstInfo out of each group
- mapTc (mkGenericInstance mod clas loc) groups `thenTc` \ inst_infos ->
+ mapTc (mkGenericInstance clas loc) groups `thenTc` \ inst_infos ->
-- Check that there is only one InstInfo for each type constructor
-- The main way this can fail is if you write
-- f {| x+y |} ... = ...
-- Then at this point we'll have an InstInfo for each
let
- bad_groups = [group | group <- equivClassesByUniq get_uniq inst_infos,
+ tc_inst_infos :: [(TyCon, InstInfo)]
+ tc_inst_infos = [(simpleInstInfoTyCon i, i) | i <- inst_infos]
+
+ bad_groups = [group | group <- equivClassesByUniq get_uniq tc_inst_infos,
length group > 1]
- get_uniq inst = getUnique (simpleInstInfoTyCon inst)
+ get_uniq (tc,_) = getUnique tc
in
mapTc (addErrTc . dupGenericInsts) bad_groups `thenTc_`
-- Check that there is an InstInfo for each generic type constructor
let
- missing = genericTyCons `minusList` map simpleInstInfoTyCon inst_infos
+ missing = genericTyCons `minusList` [tc | (tc,_) <- tc_inst_infos]
in
checkTc (null missing) (missingGenericInstances missing) `thenTc_`
= plusAssoc_C AndMonoBinds (getGenericBinds m1) (getGenericBinds m2)
getGenericBinds (FunMonoBind id infixop matches loc)
- = mapAssoc wrap (foldr add emptyAssoc matches)
+ = mapAssoc wrap (foldl add emptyAssoc matches)
+ -- Using foldl not foldr is vital, else
+ -- we reverse the order of the bindings!
where
- add match env = case maybeGenericMatch match of
+ add env match = case maybeGenericMatch match of
Nothing -> env
Just (ty, match') -> extendAssoc_C (++) env (ty, [match'])
wrap ms = FunMonoBind id infixop ms loc
---------------------------------
-mkGenericInstance :: Module -> Class -> SrcLoc
+mkGenericInstance :: Class -> SrcLoc
-> (RenamedHsType, RenamedMonoBinds)
-> TcM InstInfo
-mkGenericInstance mod clas loc (hs_ty, binds)
+mkGenericInstance clas loc (hs_ty, binds)
-- Make a generic instance declaration
-- For example: instance (C a, C b) => C (a+b) where { binds }
(badGenericInstanceType binds) `thenTc_`
-- Make the dictionary function.
- newDFunName mod clas [inst_ty] loc `thenNF_Tc` \ dfun_name ->
+ newDFunName clas [inst_ty] loc `thenNF_Tc` \ dfun_name ->
let
inst_theta = [mkClassPred clas [mkTyVarTy tv] | tv <- tyvars]
inst_tys = [inst_ty]
dfun_id = mkDictFunId dfun_name clas tyvars inst_tys inst_theta
in
- returnTc (InstInfo clas tyvars inst_tys inst_theta dfun_id binds loc [])
- -- The "[]" means "no pragmas"
+ returnTc (InstInfo { iLocal = True, iDFunId = dfun_id,
+ iBinds = binds, iPrags = [] })
\end{code}
%************************************************************************
\begin{code}
-tcInstDecls2 :: Bag InstInfo
+tcInstDecls2 :: [InstInfo]
-> NF_TcM (LIE, TcMonoBinds)
tcInstDecls2 inst_decls
- = foldBag combine tcInstDecl2 (returnNF_Tc (emptyLIE, EmptyMonoBinds)) inst_decls
+-- = foldBag combine tcInstDecl2 (returnNF_Tc (emptyLIE, EmptyMonoBinds)) inst_decls
+ = foldr combine (returnNF_Tc (emptyLIE, EmptyMonoBinds))
+ (map tcInstDecl2 inst_decls)
where
combine tc1 tc2 = tc1 `thenNF_Tc` \ (lie1, binds1) ->
tc2 `thenNF_Tc` \ (lie2, binds2) ->
\begin{code}
tcInstDecl2 :: InstInfo -> NF_TcM (LIE, TcMonoBinds)
-tcInstDecl2 (InstInfo clas inst_tyvars inst_tys
- inst_decl_theta
- dfun_id monobinds
- locn uprags)
- | not (isLocallyDefined dfun_id)
+tcInstDecl2 (InstInfo { iLocal = is_local, iDFunId = dfun_id,
+ iBinds = monobinds, iPrags = uprags })
+ | not is_local
= returnNF_Tc (emptyLIE, EmptyMonoBinds)
| otherwise
= -- Prime error recovery
recoverNF_Tc (returnNF_Tc (emptyLIE, EmptyMonoBinds)) $
- tcAddSrcLoc locn $
+ tcAddSrcLoc (getSrcLoc dfun_id) $
-- Instantiate the instance decl with tc-style type variables
tcInstId dfun_id `thenNF_Tc` \ (inst_tyvars', dfun_theta', dict_ty') ->
let
- (clas, inst_tys') = expectJust "tcInstDecl2" (splitDictTy_maybe dict_ty')
+ (clas, inst_tys') = splitDictTy dict_ty'
origin = InstanceDeclOrigin
(class_tyvars, sc_theta, _, op_items) = classBigSig clas
dm_ids = [dm_id | (_, DefMeth dm_id) <- op_items]
sel_names = [idName sel_id | (sel_id, _) <- op_items]
- -- Instantiate the theta found in the original instance decl
- inst_decl_theta' = substTheta (mkTopTyVarSubst inst_tyvars (mkTyVarTys inst_tyvars'))
- inst_decl_theta
-
-- Instantiate the super-class context with inst_tys
sc_theta' = substClasses (mkTopTyVarSubst class_tyvars inst_tys') sc_theta
-- Find any definitions in monobinds that aren't from the class
bad_bndrs = collectMonoBinders monobinds `minusList` sel_names
+
+ -- The type variable from the dict fun actually scope
+ -- over the bindings. They were gotten from
+ -- the original instance declaration
+ (inst_tyvars, _) = splitForAllTys (idType dfun_id)
in
-- Check that all the method bindings come from this class
mapTc (addErrTc . badMethodErr clas) bad_bndrs `thenNF_Tc_`
-- Create dictionary Ids from the specified instance contexts.
newClassDicts origin sc_theta' `thenNF_Tc` \ (sc_dicts, sc_dict_ids) ->
newDicts origin dfun_theta' `thenNF_Tc` \ (dfun_arg_dicts, dfun_arg_dicts_ids) ->
- newDicts origin inst_decl_theta' `thenNF_Tc` \ (inst_decl_dicts, _) ->
newClassDicts origin [(clas,inst_tys')] `thenNF_Tc` \ (this_dict, [this_dict_id]) ->
tcExtendTyVarEnvForMeths inst_tyvars inst_tyvars' (
-- Default-method Ids may be mentioned in synthesised RHSs
mapAndUnzip3Tc (tcMethodBind clas origin inst_tyvars' inst_tys'
- inst_decl_theta'
+ dfun_theta'
monobinds uprags True)
op_items
)) `thenTc` \ (method_binds_s, insts_needed_s, meth_lies_w_ids) ->
methods_lie = plusLIEs insts_needed_s
in
- -- Ditto method bindings
+ -- Simplify the constraints from methods
tcAddErrCtxt methodCtxt (
tcSimplifyAndCheck
(ptext SLIT("instance declaration context"))
methods_lie
) `thenTc` \ (const_lie1, lie_binds1) ->
- -- 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.
+ -- Figure out bindings for the superclass context
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
- -- this to make sure it can be done.
-
- -- 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* tcSimplify
- 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!!
-- 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 eRROR_ID) [(unUsgTy . idType) this_dict_id])
+ HsApp (TyApp (HsVar eRROR_ID) [idType this_dict_id])
(HsLit (HsString msg))
| otherwise -- The common case
\begin{code}
scrutiniseInstanceConstraint pred
- | opt_AllowUndecidableInstances
- = returnNF_Tc ()
+ = getDOptsTc `thenTc` \ dflags -> case () of
+ ()
+ | dopt Opt_AllowUndecidableInstances dflags
+ -> returnNF_Tc ()
- | Just (clas,tys) <- getClassTys_maybe pred,
- all isTyVarTy tys
- = returnNF_Tc ()
+ | Just (clas,tys) <- getClassTys_maybe pred,
+ all isTyVarTy tys
+ -> returnNF_Tc ()
- | otherwise
- = addErrTc (instConstraintErr pred)
+ | otherwise
+ -> addErrTc (instConstraintErr pred)
scrutiniseInstanceHead clas inst_taus
- | -- CCALL CHECK
+ = getDOptsTc `thenTc` \ dflags -> case () of
+ ()
+ | -- CCALL CHECK
-- A user declaration of a CCallable/CReturnable instance
-- must be for a "boxed primitive" type.
- (clas `hasKey` cCallableClassKey && not (ccallable_type first_inst_tau)) ||
- (clas `hasKey` cReturnableClassKey && not (creturnable_type first_inst_tau))
- = addErrTc (nonBoxedPrimCCallErr clas first_inst_tau)
-
- -- DERIVING CHECK
- -- It is obviously illegal to have an explicit instance
- -- for something that we are also planning to `derive'
- | maybeToBool alg_tycon_app_maybe && clas `elem` (tyConDerivings alg_tycon)
- = addErrTc (derivingWhenInstanceExistsErr clas first_inst_tau)
- -- Kind check will have ensured inst_taus is of length 1
+ (clas `hasKey` cCallableClassKey
+ && not (ccallable_type dflags first_inst_tau))
+ ||
+ (clas `hasKey` cReturnableClassKey
+ && not (creturnable_type first_inst_tau))
+ -> addErrTc (nonBoxedPrimCCallErr clas first_inst_tau)
-- Allow anything for AllowUndecidableInstances
- | opt_AllowUndecidableInstances
- = returnNF_Tc ()
+ | dopt Opt_AllowUndecidableInstances dflags
+ -> returnNF_Tc ()
-- If GlasgowExts then check at least one isn't a type variable
- | opt_GlasgowExts
- = if all isTyVarTy inst_taus then
- addErrTc (instTypeErr clas inst_taus (text "There must be at least one non-type-variable in the instance head"))
- else
- returnNF_Tc ()
+ | dopt Opt_GlasgowExts dflags
+ -> if all isTyVarTy inst_taus
+ then addErrTc (instTypeErr clas inst_taus
+ (text "There must be at least one non-type-variable in the instance head"))
+ else returnNF_Tc ()
-- WITH HASKELL 1.4, MUST HAVE C (T a b c)
- | not (length inst_taus == 1 &&
- 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 (varSetElems (tyVarsOfTypes arg_tys)) == length arg_tys
- -- This last condition checks that all the type variables are distinct
- )
- = addErrTc (instTypeErr clas inst_taus
- (text "the instance type must be of form (T a b c)" $$
- text "where T is not a synonym, and a,b,c are distinct type variables")
- )
-
- | otherwise
- = returnNF_Tc ()
+ | not (length inst_taus == 1 &&
+ maybeToBool maybe_tycon_app && -- Yes, there's a type constuctor
+ not (isSynTyCon tycon) && -- ...but not a synonym
+ all isTyVarTy arg_tys && -- Applied to type variables
+ length (varSetElems (tyVarsOfTypes arg_tys)) == length arg_tys
+ -- This last condition checks that all the type variables are distinct
+ )
+ -> addErrTc (instTypeErr clas inst_taus
+ (text "the instance type must be of form (T a b c)" $$
+ text "where T is not a synonym, and a,b,c are distinct type variables")
+ )
+
+ | otherwise
+ -> returnNF_Tc ()
where
(first_inst_tau : _) = inst_taus
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
- Just (alg_tycon, _, _) = alg_tycon_app_maybe
-
-ccallable_type ty = isFFIArgumentTy False {- Not safe call -} ty
-creturnable_type ty = isFFIResultTy ty
+ ccallable_type dflags ty = isFFIArgumentTy dflags False {- Not safe call -} ty
+ creturnable_type ty = isFFIResultTy ty
\end{code}
\begin{code}
tcAddDeclCtxt decl thing_inside
- = tcAddSrcLoc loc $
+ = tcAddSrcLoc (tcdLoc decl) $
tcAddErrCtxt ctxt $
thing_inside
where
- (name, loc, thing)
- = case decl of
- (ClassDecl _ name _ _ _ _ _ _ loc) -> (name, loc, "class")
- (TySynonym name _ _ loc) -> (name, loc, "type synonym")
- (TyData NewType _ name _ _ _ _ _ loc _ _) -> (name, loc, "newtype")
- (TyData DataType _ name _ _ _ _ _ loc _ _) -> (name, loc, "data type")
+ thing = case decl of
+ ClassDecl {} -> "class"
+ TySynonym {} -> "type synonym"
+ TyData {tcdND = NewType} -> "newtype"
+ TyData {tcdND = DataType} -> "data type"
ctxt = hsep [ptext SLIT("In the"), text thing,
- ptext SLIT("declaration for"), quotes (ppr name)]
+ ptext SLIT("declaration for"), quotes (ppr (tcdName decl))]
\end{code}
\begin{code}
-dupGenericInsts inst_infos
+dupGenericInsts tc_inst_infos
= vcat [ptext SLIT("More than one type pattern for a single generic type constructor:"),
- nest 4 (vcat (map (ppr . simpleInstInfoTy) inst_infos)),
+ nest 4 (vcat (map ppr_inst_ty tc_inst_infos)),
ptext SLIT("All the type patterns for a generic type constructor must be identical")
]
+ where
+ ppr_inst_ty (tc,inst) = ppr (simpleInstInfoTy inst)
instTypeErr clas tys msg
= sep [ptext SLIT("Illegal instance declaration for") <+> quotes (pprConstraint clas tys),
nest 4 (parens msg)
]
-derivingWhenInstanceExistsErr clas tycon
- = hang (hsep [ptext SLIT("Deriving class"),
- quotes (ppr clas),
- ptext SLIT("type"), quotes (ppr tycon)])
- 4 (ptext SLIT("when an explicit instance exists"))
-
nonBoxedPrimCCallErr clas inst_ty
= hang (ptext SLIT("Unacceptable instance type for ccall-ish class"))
4 (hsep [ ptext SLIT("class"), ppr clas, ptext SLIT("type"),
ppr inst_ty])
methodCtxt = ptext SLIT("When checking the methods of an instance declaration")
-superClassCtxt = ptext SLIT("When checking the superclasses of an instance declaration")
+superClassCtxt = ptext SLIT("When checking the super-classes of an instance declaration")
\end{code}