2 % (c) The AQUA Project, Glasgow University, 1998
4 \section[StdIdInfo]{Standard unfoldings}
6 This module contains definitions for the IdInfo for things that
7 have a standard form, namely:
11 * method and superclass selectors
12 * primitive operations
16 mkSpecPragmaId, mkWorkerId,
18 mkDictFunId, mkDefaultMethodId,
21 mkDataConId, mkDataConWrapId,
23 mkPrimOpId, mkCCallOpId,
25 -- And some particular Ids; see below for why they are wired in
27 unsafeCoerceId, realWorldPrimId,
28 eRROR_ID, rEC_SEL_ERROR_ID, pAT_ERROR_ID, rEC_CON_ERROR_ID,
29 rEC_UPD_ERROR_ID, iRREFUT_PAT_ERROR_ID, nON_EXHAUSTIVE_GUARDS_ERROR_ID,
30 nO_METHOD_BINDING_ERROR_ID, aBSENT_ERROR_ID, pAR_ERROR_ID
33 #include "HsVersions.h"
36 import TysPrim ( openAlphaTyVars, alphaTyVar, alphaTy,
37 intPrimTy, realWorldStatePrimTy
39 import TysWiredIn ( boolTy, charTy, mkListTy )
40 import PrelNames ( pREL_ERR, pREL_GHC )
41 import PrelRules ( primOpRule )
42 import Rules ( addRule )
43 import Type ( Type, ClassContext, mkDictTy, mkDictTys, mkTyConApp, mkTyVarTys,
44 mkFunTys, mkFunTy, mkSigmaTy, classesToPreds,
45 isUnLiftedType, mkForAllTys, mkTyVarTy, tyVarsOfType, tyVarsOfTypes,
46 splitSigmaTy, splitFunTy_maybe,
47 splitFunTys, splitForAllTys, unUsgTy,
50 import Module ( Module )
51 import CoreUtils ( exprType, mkInlineMe )
52 import CoreUnfold ( mkTopUnfolding, mkCompulsoryUnfolding, mkOtherCon )
53 import Literal ( Literal(..) )
54 import Subst ( mkTopTyVarSubst, substClasses )
55 import TyCon ( TyCon, isNewTyCon, tyConTyVars, tyConDataCons, isDataTyCon,
56 tyConTheta, isProductTyCon, isUnboxedTupleTyCon )
57 import Class ( Class, classBigSig, classTyCon, classTyVars, classSelIds )
58 import Var ( Id, TyVar )
59 import VarSet ( isEmptyVarSet )
60 import Name ( mkDerivedName, mkWiredInIdName, mkLocalName,
61 mkWorkerOcc, mkSuperDictSelOcc, mkCCallName,
64 import OccName ( mkSrcVarOcc )
65 import PrimOp ( PrimOp(DataToTagOp, CCallOp),
66 primOpSig, mkPrimOpIdName,
69 import Demand ( wwStrict, wwPrim, mkStrictnessInfo )
70 import DataCon ( DataCon, StrictnessMark(..),
71 dataConFieldLabels, dataConRepArity, dataConTyCon,
72 dataConArgTys, dataConRepType, dataConRepStrictness,
73 dataConName, dataConTheta,
74 dataConSig, dataConStrictMarks, dataConId
76 import Id ( idType, mkId,
77 mkVanillaId, mkTemplateLocals,
78 mkTemplateLocal, setInlinePragma, idCprInfo
80 import IdInfo ( IdInfo, vanillaIdInfo, mkIdInfo,
81 exactArity, setUnfoldingInfo, setCafInfo, setCprInfo,
82 setArityInfo, setInlinePragInfo, setSpecInfo,
83 mkStrictnessInfo, setStrictnessInfo,
84 IdFlavour(..), InlinePragInfo(..), CafInfo(..), StrictnessInfo(..), CprInfo(..)
86 import FieldLabel ( FieldLabel, FieldLabelTag, mkFieldLabel, fieldLabelName,
87 firstFieldLabelTag, allFieldLabelTags, fieldLabelType
92 import Maybe ( isJust )
95 import UnicodeUtil ( stringToUtf8 )
100 %************************************************************************
102 \subsection{Wired in Ids}
104 %************************************************************************
108 = [ -- These error-y things are wired in because we don't yet have
109 -- a way to express in an interface file that the result type variable
110 -- is 'open'; that is can be unified with an unboxed type
112 -- [The interface file format now carry such information, but there's
113 -- no way yet of expressing at the definition site for these error-reporting
114 -- functions that they have an 'open' result type. -- sof 1/99]
118 , iRREFUT_PAT_ERROR_ID
119 , nON_EXHAUSTIVE_GUARDS_ERROR_ID
120 , nO_METHOD_BINDING_ERROR_ID
126 -- These two can't be defined in Haskell
133 %************************************************************************
135 \subsection{Easy ones}
137 %************************************************************************
140 mkSpecPragmaId occ uniq ty loc
141 = mkId (mkLocalName uniq occ loc) ty (mkIdInfo SpecPragmaId)
142 -- Maybe a SysLocal? But then we'd lose the location
144 mkDefaultMethodId dm_name rec_c ty
145 = mkVanillaId dm_name ty
147 mkWorkerId uniq unwrkr ty
148 = mkVanillaId (mkDerivedName mkWorkerOcc (getName unwrkr) uniq) ty
151 %************************************************************************
153 \subsection{Data constructors}
155 %************************************************************************
158 mkDataConId :: Name -> DataCon -> Id
159 -- Makes the *worker* for the data constructor; that is, the function
160 -- that takes the reprsentation arguments and builds the constructor.
161 mkDataConId work_name data_con
162 = mkId work_name (dataConRepType data_con) info
164 info = mkIdInfo (DataConId data_con)
165 `setArityInfo` exactArity arity
166 `setStrictnessInfo` strict_info
167 `setCprInfo` cpr_info
169 arity = dataConRepArity data_con
171 strict_info = mkStrictnessInfo (dataConRepStrictness data_con, False)
173 cpr_info | isProductTyCon tycon &&
174 not (isUnboxedTupleTyCon tycon) &&
175 arity > 0 = ReturnsCPR
176 | otherwise = NoCPRInfo
178 tycon = dataConTyCon data_con
179 -- Newtypes don't have a worker at all
181 -- If we are a product with 0 args we must be void(like)
182 -- We can't create an unboxed tuple with 0 args for this
183 -- and since Void has only one, constant value it should
184 -- just mean returning a pointer to a pre-existing cell.
185 -- So we won't really gain from doing anything fancy
186 -- and we treat this case as Top.
189 The wrapper for a constructor is an ordinary top-level binding that evaluates
190 any strict args, unboxes any args that are going to be flattened, and calls
193 We're going to build a constructor that looks like:
195 data (Data a, C b) => T a b = T1 !a !Int b
198 \d1::Data a, d2::C b ->
199 \p q r -> case p of { p ->
201 Con T1 [a,b] [p,q,r]}}
205 * d2 is thrown away --- a context in a data decl is used to make sure
206 one *could* construct dictionaries at the site the constructor
207 is used, but the dictionary isn't actually used.
209 * We have to check that we can construct Data dictionaries for
210 the types a and Int. Once we've done that we can throw d1 away too.
212 * We use (case p of q -> ...) to evaluate p, rather than "seq" because
213 all that matters is that the arguments are evaluated. "seq" is
214 very careful to preserve evaluation order, which we don't need
217 You might think that we could simply give constructors some strictness
218 info, like PrimOps, and let CoreToStg do the let-to-case transformation.
219 But we don't do that because in the case of primops and functions strictness
220 is a *property* not a *requirement*. In the case of constructors we need to
221 do something active to evaluate the argument.
223 Making an explicit case expression allows the simplifier to eliminate
224 it in the (common) case where the constructor arg is already evaluated.
227 mkDataConWrapId data_con
230 wrap_id = mkId (dataConName data_con) wrap_ty info
231 work_id = dataConId data_con
233 info = mkIdInfo (DataConWrapId data_con)
234 `setUnfoldingInfo` mkTopUnfolding (mkInlineMe wrap_rhs)
235 `setCprInfo` cpr_info
236 -- The Cpr info can be important inside INLINE rhss, where the
237 -- wrapper constructor isn't inlined
238 `setArityInfo` exactArity arity
239 -- It's important to specify the arity, so that partial
240 -- applications are treated as values
241 `setCafInfo` NoCafRefs
242 -- The wrapper Id ends up in STG code as an argument,
243 -- sometimes before its definition, so we want to
244 -- signal that it has no CAFs
246 wrap_ty = mkForAllTys all_tyvars $
250 cpr_info = idCprInfo work_id
252 wrap_rhs | isNewTyCon tycon
253 = ASSERT( null ex_tyvars && null ex_dict_args && length orig_arg_tys == 1 )
254 -- No existentials on a newtype, but it can have a context
255 -- e.g. newtype Eq a => T a = MkT (...)
257 mkLams tyvars $ mkLams dict_args $ Lam id_arg1 $
258 Note (Coerce result_ty (head orig_arg_tys)) (Var id_arg1)
260 {- I nuked this because map (:) xs would create a
261 new local lambda for the (:) in core-to-stg.
262 There isn't a defn for the worker!
264 | null dict_args && all not_marked_strict strict_marks
265 = Var work_id -- The common case. Not only is this efficient,
266 -- but it also ensures that the wrapper is replaced
267 -- by the worker even when there are no args.
271 -- This is really important in rule matching,
272 -- which is a bit sad. (We could match on the wrappers,
273 -- but that makes it less likely that rules will match
274 -- when we bring bits of unfoldings together
278 = mkLams all_tyvars $ mkLams dict_args $
279 mkLams ex_dict_args $ mkLams id_args $
280 foldr mk_case con_app
281 (zip (ex_dict_args++id_args) strict_marks) i3 []
283 con_app i rep_ids = mkApps (Var work_id)
284 (map varToCoreExpr (all_tyvars ++ reverse rep_ids))
286 (tyvars, theta, ex_tyvars, ex_theta, orig_arg_tys, tycon) = dataConSig data_con
287 all_tyvars = tyvars ++ ex_tyvars
289 dict_tys = mkDictTys theta
290 ex_dict_tys = mkDictTys ex_theta
291 all_arg_tys = dict_tys ++ ex_dict_tys ++ orig_arg_tys
292 result_ty = mkTyConApp tycon (mkTyVarTys tyvars)
294 mkLocals i tys = (zipWith mkTemplateLocal [i..i+n-1] tys, i+n)
298 (dict_args, i1) = mkLocals 1 dict_tys
299 (ex_dict_args,i2) = mkLocals i1 ex_dict_tys
300 (id_args,i3) = mkLocals i2 orig_arg_tys
302 (id_arg1:_) = id_args -- Used for newtype only
304 strict_marks = dataConStrictMarks data_con
305 not_marked_strict NotMarkedStrict = True
306 not_marked_strict other = False
310 :: (Id, StrictnessMark) -- arg, strictness
311 -> (Int -> [Id] -> CoreExpr) -- body
312 -> Int -- next rep arg id
313 -> [Id] -- rep args so far
315 mk_case (arg,strict) body i rep_args
317 NotMarkedStrict -> body i (arg:rep_args)
319 | isUnLiftedType (idType arg) -> body i (arg:rep_args)
321 Case (Var arg) arg [(DEFAULT,[], body i (arg:rep_args))]
323 MarkedUnboxed con tys ->
324 Case (Var arg) arg [(DataAlt con, con_args,
325 body i' (reverse con_args++rep_args))]
327 (con_args,i') = mkLocals i tys
331 %************************************************************************
333 \subsection{Record selectors}
335 %************************************************************************
337 We're going to build a record selector unfolding that looks like this:
339 data T a b c = T1 { ..., op :: a, ...}
340 | T2 { ..., op :: a, ...}
343 sel = /\ a b c -> \ d -> case d of
348 Similarly for newtypes
350 newtype N a = MkN { unN :: a->a }
353 unN n = coerce (a->a) n
355 We need to take a little care if the field has a polymorphic type:
357 data R = R { f :: forall a. a->a }
361 f :: forall a. R -> a -> a
362 f = /\ a \ r = case r of
365 (not f :: R -> forall a. a->a, which gives the type inference mechanism
366 problems at call sites)
368 Similarly for newtypes
370 newtype N = MkN { unN :: forall a. a->a }
372 unN :: forall a. N -> a -> a
373 unN = /\a -> \n:N -> coerce (a->a) n
376 mkRecordSelId tycon field_label unpack_id unpackUtf8_id
377 -- Assumes that all fields with the same field label have the same type
379 -- Annoyingly, we have to pass in the unpackCString# Id, because
380 -- we can't conjure it up out of thin air
383 sel_id = mkId (fieldLabelName field_label) selector_ty info
385 field_ty = fieldLabelType field_label
386 data_cons = tyConDataCons tycon
387 tyvars = tyConTyVars tycon -- These scope over the types in
388 -- the FieldLabels of constructors of this type
389 tycon_theta = tyConTheta tycon -- The context on the data decl
390 -- eg data (Eq a, Ord b) => T a b = ...
391 (field_tyvars,field_tau) = splitForAllTys field_ty
393 data_ty = mkTyConApp tycon tyvar_tys
394 tyvar_tys = mkTyVarTys tyvars
396 -- Very tiresomely, the selectors are (unnecessarily!) overloaded over
397 -- just the dictionaries in the types of the constructors that contain
398 -- the relevant field. Urgh.
399 -- NB: this code relies on the fact that DataCons are quantified over
400 -- the identical type variables as their parent TyCon
401 dict_tys = [mkDictTy cls tys | (cls, tys) <- tycon_theta, needed_dict (cls, tys)]
402 needed_dict pred = or [ pred `elem` (dataConTheta dc)
403 | (DataAlt dc, _, _) <- the_alts]
406 selector_ty = mkForAllTys tyvars $ mkForAllTys field_tyvars $
407 mkFunTys dict_tys $ mkFunTy data_ty field_tau
409 info = mkIdInfo (RecordSelId field_label)
410 `setArityInfo` exactArity (1 + length dict_tys)
411 `setUnfoldingInfo` unfolding
412 `setCafInfo` NoCafRefs
413 -- ToDo: consider adding further IdInfo
415 unfolding = mkTopUnfolding sel_rhs
418 (data_id:dict_ids) = mkTemplateLocals (data_ty:dict_tys)
419 alts = map mk_maybe_alt data_cons
420 the_alts = catMaybes alts
421 default_alt | all isJust alts = [] -- No default needed
422 | otherwise = [(DEFAULT, [], error_expr)]
424 sel_rhs | isNewTyCon tycon = new_sel_rhs
425 | otherwise = data_sel_rhs
427 data_sel_rhs = mkLams tyvars $ mkLams field_tyvars $
428 mkLams dict_ids $ Lam data_id $
429 Case (Var data_id) data_id (the_alts ++ default_alt)
431 new_sel_rhs = mkLams tyvars $ mkLams field_tyvars $ Lam data_id $
432 Note (Coerce (unUsgTy field_tau) (unUsgTy data_ty)) (Var data_id)
434 mk_maybe_alt data_con
435 = case maybe_the_arg_id of
437 Just the_arg_id -> Just (DataAlt data_con, arg_ids,
438 mkVarApps (Var the_arg_id) field_tyvars)
440 arg_ids = mkTemplateLocals (dataConArgTys data_con tyvar_tys)
441 -- The first one will shadow data_id, but who cares
442 field_lbls = dataConFieldLabels data_con
443 maybe_the_arg_id = assocMaybe (field_lbls `zip` arg_ids) field_label
445 error_expr = mkApps (Var rEC_SEL_ERROR_ID) [Type (unUsgTy field_tau), err_string]
446 -- preserves invariant that type args are *not* usage-annotated on top. KSW 1999-04.
448 | all safeChar full_msg
449 = App (Var unpack_id) (Lit (MachStr (_PK_ full_msg)))
451 = App (Var unpackUtf8_id) (Lit (MachStr (_PK_ (stringToUtf8 (map ord full_msg)))))
453 safeChar c = c >= '\1' && c <= '\xFF'
454 -- TODO: Putting this Unicode stuff here is ugly. Find a better
455 -- generic place to make string literals. This logic is repeated
457 full_msg = showSDoc (sep [text "No match in record selector", ppr sel_id])
461 %************************************************************************
463 \subsection{Dictionary selectors}
465 %************************************************************************
467 Selecting a field for a dictionary. If there is just one field, then
468 there's nothing to do.
470 ToDo: unify with mkRecordSelId.
473 mkDictSelId :: Name -> Class -> Id
474 mkDictSelId name clas
478 sel_id = mkId name ty info
479 field_lbl = mkFieldLabel name tycon ty tag
480 tag = assoc "MkId.mkDictSelId" (classSelIds clas `zip` allFieldLabelTags) sel_id
482 info = mkIdInfo (RecordSelId field_lbl)
483 `setArityInfo` exactArity 1
484 `setUnfoldingInfo` unfolding
485 `setCafInfo` NoCafRefs
487 -- We no longer use 'must-inline' on record selectors. They'll
488 -- inline like crazy if they scrutinise a constructor
490 unfolding = mkTopUnfolding rhs
492 tyvars = classTyVars clas
494 tycon = classTyCon clas
495 [data_con] = tyConDataCons tycon
496 tyvar_tys = mkTyVarTys tyvars
497 arg_tys = dataConArgTys data_con tyvar_tys
498 the_arg_id = arg_ids !! (tag - firstFieldLabelTag)
500 dict_ty = mkDictTy clas tyvar_tys
501 (dict_id:arg_ids) = mkTemplateLocals (dict_ty : arg_tys)
503 rhs | isNewTyCon tycon = mkLams tyvars $ Lam dict_id $
504 Note (Coerce (head arg_tys) dict_ty) (Var dict_id)
505 | otherwise = mkLams tyvars $ Lam dict_id $
506 Case (Var dict_id) dict_id
507 [(DataAlt data_con, arg_ids, Var the_arg_id)]
511 %************************************************************************
513 \subsection{Primitive operations
515 %************************************************************************
518 mkPrimOpId :: PrimOp -> Id
522 (tyvars,arg_tys,res_ty, arity, strict_info) = primOpSig prim_op
523 ty = mkForAllTys tyvars (mkFunTys arg_tys res_ty)
524 name = mkPrimOpIdName prim_op id
525 id = mkId name ty info
527 info = mkIdInfo (PrimOpId prim_op)
529 `setArityInfo` exactArity arity
530 `setStrictnessInfo` strict_info
532 rules = addRule id emptyCoreRules (primOpRule prim_op)
535 -- For each ccall we manufacture a separate CCallOpId, giving it
536 -- a fresh unique, a type that is correct for this particular ccall,
537 -- and a CCall structure that gives the correct details about calling
540 -- The *name* of this Id is a local name whose OccName gives the full
541 -- details of the ccall, type and all. This means that the interface
542 -- file reader can reconstruct a suitable Id
544 mkCCallOpId :: Unique -> CCall -> Type -> Id
545 mkCCallOpId uniq ccall ty
546 = ASSERT( isEmptyVarSet (tyVarsOfType ty) )
547 -- A CCallOpId should have no free type variables;
548 -- when doing substitutions won't substitute over it
551 occ_str = showSDocIface (braces (pprCCallOp ccall <+> ppr ty))
552 -- The "occurrence name" of a ccall is the full info about the
553 -- ccall; it is encoded, but may have embedded spaces etc!
555 name = mkCCallName uniq occ_str
556 prim_op = CCallOp ccall
558 info = mkIdInfo (PrimOpId prim_op)
559 `setArityInfo` exactArity arity
560 `setStrictnessInfo` strict_info
562 (_, tau) = splitForAllTys ty
563 (arg_tys, _) = splitFunTys tau
564 arity = length arg_tys
565 strict_info = mkStrictnessInfo (take arity (repeat wwPrim), False)
569 %************************************************************************
571 \subsection{DictFuns}
573 %************************************************************************
576 mkDictFunId :: Name -- Name to use for the dict fun;
583 mkDictFunId dfun_name clas inst_tyvars inst_tys inst_decl_theta
584 = mkVanillaId dfun_name dfun_ty
586 dfun_theta = classesToPreds inst_decl_theta
588 {- 1 dec 99: disable the Mark Jones optimisation for the sake
589 of compatibility with Hugs.
590 See `types/InstEnv' for a discussion related to this.
592 (class_tyvars, sc_theta, _, _) = classBigSig clas
593 not_const (clas, tys) = not (isEmptyVarSet (tyVarsOfTypes tys))
594 sc_theta' = substClasses (mkTopTyVarSubst class_tyvars inst_tys) sc_theta
595 dfun_theta = case inst_decl_theta of
596 [] -> [] -- If inst_decl_theta is empty, then we don't
597 -- want to have any dict arguments, so that we can
598 -- expose the constant methods.
600 other -> nub (inst_decl_theta ++ filter not_const sc_theta')
601 -- Otherwise we pass the superclass dictionaries to
602 -- the dictionary function; the Mark Jones optimisation.
604 -- NOTE the "nub". I got caught by this one:
605 -- class Monad m => MonadT t m where ...
606 -- instance Monad m => MonadT (EnvT env) m where ...
607 -- Here, the inst_decl_theta has (Monad m); but so
608 -- does the sc_theta'!
610 -- NOTE the "not_const". I got caught by this one too:
611 -- class Foo a => Baz a b where ...
612 -- instance Wob b => Baz T b where..
613 -- Now sc_theta' has Foo T
615 dfun_ty = mkSigmaTy inst_tyvars dfun_theta (mkDictTy clas inst_tys)
619 %************************************************************************
621 \subsection{Un-definable}
623 %************************************************************************
625 These two can't be defined in Haskell.
627 unsafeCoerce# isn't so much a PrimOp as a phantom identifier, that
628 just gets expanded into a type coercion wherever it occurs. Hence we
629 add it as a built-in Id with an unfolding here.
631 The type variables we use here are "open" type variables: this means
632 they can unify with both unlifted and lifted types. Hence we provide
633 another gun with which to shoot yourself in the foot.
637 = pcMiscPrelId unsafeCoerceIdKey pREL_GHC SLIT("unsafeCoerce#") ty info
640 `setUnfoldingInfo` mkCompulsoryUnfolding rhs
643 ty = mkForAllTys [openAlphaTyVar,openBetaTyVar]
644 (mkFunTy openAlphaTy openBetaTy)
645 [x] = mkTemplateLocals [openAlphaTy]
646 rhs = mkLams [openAlphaTyVar,openBetaTyVar,x] $
647 Note (Coerce openBetaTy openAlphaTy) (Var x)
651 @getTag#@ is another function which can't be defined in Haskell. It needs to
652 evaluate its argument and call the dataToTag# primitive.
656 = pcMiscPrelId getTagIdKey pREL_GHC SLIT("getTag#") ty info
659 `setUnfoldingInfo` mkCompulsoryUnfolding rhs
660 -- We don't provide a defn for this; you must inline it
662 ty = mkForAllTys [alphaTyVar] (mkFunTy alphaTy intPrimTy)
663 [x,y] = mkTemplateLocals [alphaTy,alphaTy]
664 rhs = mkLams [alphaTyVar,x] $
665 Case (Var x) y [ (DEFAULT, [], mkApps (Var dataToTagId) [Type alphaTy, Var y]) ]
667 dataToTagId = mkPrimOpId DataToTagOp
670 @realWorld#@ used to be a magic literal, \tr{void#}. If things get
671 nasty as-is, change it back to a literal (@Literal@).
674 realWorldPrimId -- :: State# RealWorld
675 = pcMiscPrelId realWorldPrimIdKey pREL_GHC SLIT("realWorld#")
677 (noCafIdInfo `setUnfoldingInfo` mkOtherCon [])
678 -- The mkOtherCon makes it look that realWorld# is evaluated
679 -- which in turn makes Simplify.interestingArg return True,
680 -- which in turn makes INLINE things applied to realWorld# likely
685 %************************************************************************
687 \subsection[PrelVals-error-related]{@error@ and friends; @trace@}
689 %************************************************************************
691 GHC randomly injects these into the code.
693 @patError@ is just a version of @error@ for pattern-matching
694 failures. It knows various ``codes'' which expand to longer
695 strings---this saves space!
697 @absentErr@ is a thing we put in for ``absent'' arguments. They jolly
698 well shouldn't be yanked on, but if one is, then you will get a
699 friendly message from @absentErr@ (rather than a totally random
702 @parError@ is a special version of @error@ which the compiler does
703 not know to be a bottoming Id. It is used in the @_par_@ and @_seq_@
704 templates, but we don't ever expect to generate code for it.
708 = pc_bottoming_Id errorIdKey pREL_ERR SLIT("error") errorTy
710 = generic_ERROR_ID patErrorIdKey SLIT("patError")
712 = generic_ERROR_ID recSelErrIdKey SLIT("recSelError")
714 = generic_ERROR_ID recConErrorIdKey SLIT("recConError")
716 = generic_ERROR_ID recUpdErrorIdKey SLIT("recUpdError")
718 = generic_ERROR_ID irrefutPatErrorIdKey SLIT("irrefutPatError")
719 nON_EXHAUSTIVE_GUARDS_ERROR_ID
720 = generic_ERROR_ID nonExhaustiveGuardsErrorIdKey SLIT("nonExhaustiveGuardsError")
721 nO_METHOD_BINDING_ERROR_ID
722 = generic_ERROR_ID noMethodBindingErrorIdKey SLIT("noMethodBindingError")
725 = pc_bottoming_Id absentErrorIdKey pREL_ERR SLIT("absentErr")
726 (mkSigmaTy [openAlphaTyVar] [] openAlphaTy)
729 = pcMiscPrelId parErrorIdKey pREL_ERR SLIT("parError")
730 (mkSigmaTy [openAlphaTyVar] [] openAlphaTy) noCafIdInfo
735 %************************************************************************
737 \subsection{Utilities}
739 %************************************************************************
742 pcMiscPrelId :: Unique{-IdKey-} -> Module -> FAST_STRING -> Type -> IdInfo -> Id
743 pcMiscPrelId key mod str ty info
745 name = mkWiredInIdName key mod (mkSrcVarOcc str) imp
746 imp = mkId name ty info -- the usual case...
749 -- We lie and say the thing is imported; otherwise, we get into
750 -- a mess with dependency analysis; e.g., core2stg may heave in
751 -- random calls to GHCbase.unpackPS__. If GHCbase is the module
752 -- being compiled, then it's just a matter of luck if the definition
753 -- will be in "the right place" to be in scope.
755 pc_bottoming_Id key mod name ty
756 = pcMiscPrelId key mod name ty bottoming_info
758 bottoming_info = noCafIdInfo
759 `setStrictnessInfo` mkStrictnessInfo ([wwStrict], True)
761 -- these "bottom" out, no matter what their arguments
763 generic_ERROR_ID u n = pc_bottoming_Id u pREL_ERR n errorTy
766 noCafIdInfo = vanillaIdInfo `setCafInfo` NoCafRefs
768 (openAlphaTyVar:openBetaTyVar:_) = openAlphaTyVars
769 openAlphaTy = mkTyVarTy openAlphaTyVar
770 openBetaTy = mkTyVarTy openBetaTyVar
773 errorTy = mkUsgTy UsMany $
774 mkSigmaTy [openAlphaTyVar] [] (mkFunTys [mkUsgTy UsOnce (mkListTy charTy)]
775 (mkUsgTy UsMany openAlphaTy))
776 -- Notice the openAlphaTyVar. It says that "error" can be applied
777 -- to unboxed as well as boxed types. This is OK because it never
778 -- returns, so the return type is irrelevant.