#include "HsVersions.h"
-import CmdLineOpts ( DynFlag(..), dopt )
+import CmdLineOpts ( DynFlag(..) )
import HsSyn ( HsDecl(..), InstDecl(..), TyClDecl(..), HsType(..),
MonoBinds(..), HsExpr(..), HsLit(..), Sig(..), HsTyVarBndr(..),
import TcBinds ( tcSpecSigs )
import TcClassDcl ( tcMethodBind, badMethodErr )
import TcMonad
-import TcMType ( tcInstTyVars, checkValidTheta, UserTypeCtxt(..), SourceTyCtxt(..) )
-import TcType ( tcSplitDFunTy, tcIsTyVarTy, tcSplitTyConApp_maybe,
- tyVarsOfTypes, mkClassPred, mkTyVarTy,
- tcSplitSigmaTy, tcSplitPredTy_maybe, getClassPredTys_maybe
+import TcMType ( tcInstSigTyVars, checkValidTheta, checkValidInstHead, instTypeErr,
+ UserTypeCtxt(..), SourceTyCtxt(..) )
+import TcType ( tcSplitDFunTy, mkClassPred, mkTyVarTy, mkTyVarTys,
+ tcSplitSigmaTy, tcSplitPredTy_maybe, getClassPredTys,
+ TyVarDetails(..)
)
import Inst ( InstOrigin(..),
newDicts, instToId,
isLocalThing,
)
import InstEnv ( InstEnv, extendInstEnv )
+import PprType ( pprClassPred )
import TcMonoType ( tcHsTyVars, kcHsSigType, tcHsType, tcHsSigType, checkSigTyVars )
import TcSimplify ( tcSimplifyCheck )
import HscTypes ( HomeSymbolTable, DFunId,
import Class ( Class, DefMeth(..), classBigSig )
import Var ( idName, idType )
import VarSet ( emptyVarSet )
-import Maybes ( maybeToBool )
+import Id ( setIdLocalExported )
import MkId ( mkDictFunId )
import FunDeps ( checkInstFDs )
import Generics ( validGenericInstanceType )
import Module ( Module, foldModuleEnv )
import Name ( getSrcLoc )
-import NameSet ( unitNameSet, nameSetToList )
+import NameSet ( unitNameSet, emptyNameSet, nameSetToList )
import PrelInfo ( eRROR_ID )
-import PprType ( pprClassPred )
-import TyCon ( TyCon, isSynTyCon )
+import TyCon ( TyCon )
import Subst ( mkTopTyVarSubst, substTheta )
-import VarSet ( varSetElems )
-import TysWiredIn ( genericTyCons, isFFIArgumentTy, isFFIImportResultTy )
-import ForeignCall ( Safety(..) )
-import PrelNames ( cCallableClassKey, cReturnableClassKey, hasKey )
+import TysWiredIn ( genericTyCons )
import Name ( Name )
import SrcLoc ( SrcLoc )
-import VarSet ( varSetElems )
import Unique ( Uniquable(..) )
+import Util ( lengthExceeds )
import BasicTypes ( NewOrData(..), Fixity )
import ErrUtils ( dumpIfSet_dyn )
import ListSetOps ( Assoc, emptyAssoc, plusAssoc_C, mapAssoc,
tcHsType poly_ty `thenTc` \ poly_ty' ->
let
(tyvars, theta, tau) = tcSplitSigmaTy poly_ty'
- maybe_cls_tys = case tcSplitPredTy_maybe tau of
- Just pred -> getClassPredTys_maybe pred
- Nothing -> Nothing
- Just (clas, inst_tys) = maybe_cls_tys
+ (clas,inst_tys) = case tcSplitPredTy_maybe tau of { Just st -> getClassPredTys st }
+ -- The checkValidInstHead makes sure these splits succeed
in
- checkTc (maybeToBool maybe_cls_tys) (instHeadErr tau) `thenTc_`
-
(case maybe_dfun_name of
Nothing -> -- A source-file instance declaration
-
-- Check for respectable instance type, and context
-- but only do this for non-imported instance decls.
-- Imported ones should have been checked already, and may indeed
-- contain something illegal in normal Haskell, notably
-- instance CCallable [Char]
- getDOptsTc `thenTc` \ dflags ->
- checkValidTheta InstDeclCtxt theta `thenTc_`
- checkValidInstHead dflags theta clas inst_tys `thenTc_`
+ checkValidTheta InstThetaCtxt theta `thenTc_`
+ checkValidInstHead tau `thenTc_`
+ checkTc (checkInstFDs theta clas inst_tys)
+ (instTypeErr (pprClassPred clas inst_tys) msg) `thenTc_`
newDFunName clas inst_tys src_loc
Just dfun_name -> -- An interface-file instance declaration
returnNF_Tc dfun_name
- ) `thenNF_Tc` \ dfun_name ->
-
+ ) `thenNF_Tc` \ dfun_name ->
let
dfun_id = mkDictFunId dfun_name clas tyvars inst_tys theta
in
returnTc [InstInfo { iDFunId = dfun_id, iBinds = binds, iPrags = uprags }]
+ where
+ msg = parens (ptext SLIT("the instance types do not agree with the functional dependencies of the class"))
\end{code}
| null groups
= returnTc [] -- The comon case: no generic default methods
- | otherwise -- A local class decl with generic default methods
+ | otherwise -- A source class decl with generic default methods
= recoverNF_Tc (returnNF_Tc []) $
tcAddDeclCtxt decl $
tcLookupClass class_name `thenTc` \ clas ->
tc_inst_infos = [(simpleInstInfoTyCon i, i) | i <- inst_infos]
bad_groups = [group | group <- equivClassesByUniq get_uniq tc_inst_infos,
- length group > 1]
+ group `lengthExceeds` 1]
get_uniq (tc,_) = getUnique tc
in
mapTc (addErrTc . dupGenericInsts) bad_groups `thenTc_`
let
(inst_tyvars, dfun_theta, clas, inst_tys) = tcSplitDFunTy (idType dfun_id)
in
- tcInstTyVars inst_tyvars `thenNF_Tc` \ (inst_tyvars', _, tenv) ->
+ tcInstSigTyVars InstTv inst_tyvars `thenNF_Tc` \ inst_tyvars' ->
let
+ tenv = mkTopTyVarSubst inst_tyvars (mkTyVarTys inst_tyvars')
inst_tys' = map (substTy tenv) inst_tys
dfun_theta' = substTheta tenv dfun_theta
origin = InstanceDeclOrigin
-- Create the result bindings
let
+ local_dfun_id = setIdLocalExported dfun_id
+ -- Reason for setIdLocalExported: see notes with MkId.mkDictFunId
+
dict_constr = classDataCon clas
scs_and_meths = map instToId (sc_dicts ++ meth_insts)
this_dict_id = instToId this_dict
- inlines = unitNameSet (idName dfun_id)
+ inlines | null dfun_arg_dicts = emptyNameSet
+ | otherwise = unitNameSet (idName dfun_id)
-- Always inline the dfun; this is an experimental decision
-- because it makes a big performance difference sometimes.
-- Often it means we can do the method selection, and then
-- inline the method as well. Marcin's idea; see comments below.
+ --
+ -- BUT: don't inline it if it's a constant dictionary;
+ -- we'll get all the benefit without inlining, and we get
+ -- a **lot** of code duplication if we inline it
dict_rhs
| null scs_and_meths
= AbsBinds
zonked_inst_tyvars
(map instToId dfun_arg_dicts)
- [(inst_tyvars', dfun_id, this_dict_id)]
+ [(inst_tyvars', local_dfun_id, this_dict_id)]
inlines
(lie_binds1 `AndMonoBinds`
lie_binds2 `AndMonoBinds`
%************************************************************************
%* *
-\subsection{Checking for a decent instance type}
-%* *
-%************************************************************************
-
-@checkValidInstHead@ checks the type {\em and} its syntactic constraints:
-it must normally look like: @instance Foo (Tycon a b c ...) ...@
-
-The exceptions to this syntactic checking: (1)~if the @GlasgowExts@
-flag is on, or (2)~the instance is imported (they must have been
-compiled elsewhere). In these cases, we let them go through anyway.
-
-We can also have instances for functions: @instance Foo (a -> b) ...@.
-
-\begin{code}
-checkValidInstHead dflags theta clas inst_tys
- | null errs = returnTc ()
- | otherwise = addErrsTc errs `thenNF_Tc_` failTc
- where
- errs = check_inst_head dflags theta clas inst_tys
-
-check_inst_head dflags theta clas inst_taus
- | -- CCALL CHECK
- -- A user declaration of a CCallable/CReturnable instance
- -- must be for a "boxed primitive" type.
- (clas `hasKey` cCallableClassKey
- && not (ccallable_type dflags first_inst_tau))
- ||
- (clas `hasKey` cReturnableClassKey
- && not (creturnable_type first_inst_tau))
- = [nonBoxedPrimCCallErr clas first_inst_tau]
-
- -- If GlasgowExts then check at least one isn't a type variable
- | dopt Opt_GlasgowExts dflags
- = -- GlasgowExts case
- check_tyvars dflags clas inst_taus ++ check_fundeps dflags theta clas inst_taus
-
- -- 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 tcIsTyVarTy 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
- )
- = [instTypeErr clas inst_taus
- (text "the instance type must be of form (T a b c)" $$
- text "where T is not a synonym, and a,b,c are distinct type variables")]
-
- | otherwise
- = []
-
- where
- (first_inst_tau : _) = inst_taus
-
- -- Stuff for algebraic or -> type
- maybe_tycon_app = tcSplitTyConApp_maybe first_inst_tau
- Just (tycon, arg_tys) = maybe_tycon_app
-
- ccallable_type dflags ty = isFFIArgumentTy dflags PlayRisky ty
- creturnable_type ty = isFFIImportResultTy dflags ty
-
-check_tyvars dflags clas inst_taus
- -- Check that at least one isn't a type variable
- -- unless -fallow-undecideable-instances
- | dopt Opt_AllowUndecidableInstances dflags = []
- | not (all tcIsTyVarTy inst_taus) = []
- | otherwise = [the_err]
- where
- the_err = instTypeErr clas inst_taus msg
- msg = ptext SLIT("There must be at least one non-type-variable in the instance head")
- $$ ptext SLIT("Use -fallow-undecidable-instances to lift this restriction")
-
-check_fundeps dflags theta clas inst_taus
- | checkInstFDs theta clas inst_taus = []
- | otherwise = [the_err]
- where
- the_err = instTypeErr clas inst_taus msg
- msg = ptext SLIT("the instance types do not agree with the functional dependencies of the class")
-\end{code}
-
-
-%************************************************************************
-%* *
\subsection{Error messages}
%* *
%************************************************************************
missingGenericInstances missing
= ptext SLIT("Missing type patterns for") <+> pprQuotedList missing
-
-
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)),
where
ppr_inst_ty (tc,inst) = ppr (simpleInstInfoTy inst)
-instHeadErr ty
- = vcat [ptext SLIT("Illegal instance head:") <+> ppr ty,
- ptext SLIT("Instance head must be of form <context> => <class> <types>")]
-
-instTypeErr clas tys msg
- = sep [ptext SLIT("Illegal instance declaration for") <+>
- quotes (pprClassPred clas tys),
- nest 4 (parens msg)
- ]
-
-nonBoxedPrimCCallErr clas inst_ty
- = hang (ptext SLIT("Unacceptable instance type for ccall-ish class"))
- 4 (pprClassPred clas [inst_ty])
-
methodCtxt = ptext SLIT("When checking the methods of an instance declaration")
superClassCtxt = ptext SLIT("When checking the super-classes of an instance declaration")
\end{code}
projects / ghc-hetmet.git / blobdiff