2 % (c) The University of Glasgow 2006
3 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
5 \section[HsBinds]{Abstract syntax: top-level bindings and signatures}
7 Datatype for: @BindGroup@, @Bind@, @Sig@, @Bind@.
10 {-# OPTIONS -fno-warn-incomplete-patterns #-}
11 -- The above warning supression flag is a temporary kludge.
12 -- While working on this module you are encouraged to remove it and fix
13 -- any warnings in the module. See
14 -- http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings
16 {-# LANGUAGE DeriveDataTypeable #-}
20 import {-# SOURCE #-} HsExpr ( pprExpr, LHsExpr,
21 MatchGroup, pprFunBind,
23 import {-# SOURCE #-} HsPat ( LPat )
41 import Data.IORef( IORef )
42 import Data.Data hiding ( Fixity )
45 %************************************************************************
47 \subsection{Bindings: @BindGroup@}
49 %************************************************************************
51 Global bindings (where clauses)
54 -- During renaming, we need bindings where the left-hand sides
55 -- have been renamed but the the right-hand sides have not.
56 -- the ...LR datatypes are parametrized by two id types,
57 -- one for the left and one for the right.
58 -- Other than during renaming, these will be the same.
60 type HsLocalBinds id = HsLocalBindsLR id id
62 data HsLocalBindsLR idL idR -- Bindings in a 'let' expression
63 -- or a 'where' clause
64 = HsValBinds (HsValBindsLR idL idR)
65 | HsIPBinds (HsIPBinds idR)
67 deriving (Data, Typeable)
69 type HsValBinds id = HsValBindsLR id id
71 data HsValBindsLR idL idR -- Value bindings (not implicit parameters)
72 = ValBindsIn -- Before renaming
73 (LHsBindsLR idL idR) [LSig idR] -- Not dependency analysed
74 -- Recursive by default
76 | ValBindsOut -- After renaming
77 [(RecFlag, LHsBinds idL)] -- Dependency analysed, later bindings
78 -- in the list may depend on earlier
81 deriving (Data, Typeable)
83 type LHsBinds id = Bag (LHsBind id)
84 type LHsBind id = Located (HsBind id)
85 type HsBind id = HsBindLR id id
87 type LHsBindLR idL idR = Located (HsBindLR idL idR)
88 type LHsBindsLR idL idR = Bag (LHsBindLR idL idR)
91 = -- | FunBind is used for both functions @f x = e@
92 -- and variables @f = \x -> e@
94 -- Reason 1: Special case for type inference: see 'TcBinds.tcMonoBinds'.
96 -- Reason 2: Instance decls can only have FunBinds, which is convenient.
97 -- If you change this, you'll need to change e.g. rnMethodBinds
99 -- But note that the form @f :: a->a = ...@
100 -- parses as a pattern binding, just like
101 -- @(f :: a -> a) = ... @
104 fun_id :: Located idL,
106 fun_infix :: Bool, -- ^ True => infix declaration
108 fun_matches :: MatchGroup idR, -- ^ The payload
110 fun_co_fn :: HsWrapper, -- ^ Coercion from the type of the MatchGroup to the type of
113 -- f :: Int -> forall a. a -> a
116 -- Then the MatchGroup will have type (Int -> a' -> a')
117 -- (with a free type variable a'). The coercion will take
118 -- a CoreExpr of this type and convert it to a CoreExpr of
119 -- type Int -> forall a'. a' -> a'
120 -- Notice that the coercion captures the free a'.
122 bind_fvs :: NameSet, -- ^ After the renamer, this contains a superset of the
123 -- Names of the other binders in this binding group that
124 -- are free in the RHS of the defn
125 -- Before renaming, and after typechecking,
126 -- the field is unused; it's just an error thunk
128 fun_tick :: Maybe (Int,[Id]) -- ^ This is the (optional) module-local tick number.
131 | PatBind { -- The pattern is never a simple variable;
132 -- That case is done by FunBind
134 pat_rhs :: GRHSs idR,
135 pat_rhs_ty :: PostTcType, -- Type of the GRHSs
136 bind_fvs :: NameSet -- Same as for FunBind
139 | VarBind { -- Dictionary binding and suchlike
140 var_id :: idL, -- All VarBinds are introduced by the type checker
141 var_rhs :: LHsExpr idR, -- Located only for consistency
142 var_inline :: Bool -- True <=> inline this binding regardless
143 -- (used for implication constraints only)
146 | AbsBinds { -- Binds abstraction; TRANSLATION
148 abs_ev_vars :: [EvVar], -- Includes equality constraints
150 -- AbsBinds only gets used when idL = idR after renaming,
151 -- but these need to be idL's for the collect... code in HsUtil to have
153 abs_exports :: [([TyVar], idL, idL, TcSpecPrags)], -- (tvs, poly_id, mono_id, prags)
155 abs_ev_binds :: TcEvBinds, -- Evidence bindings
156 abs_binds :: LHsBinds idL -- Typechecked user bindings
158 deriving (Data, Typeable)
159 -- Consider (AbsBinds tvs ds [(ftvs, poly_f, mono_f) binds]
161 -- Creates bindings for (polymorphic, overloaded) poly_f
162 -- in terms of monomorphic, non-overloaded mono_f
165 -- 1. 'binds' binds mono_f
166 -- 2. ftvs is a subset of tvs
167 -- 3. ftvs includes all tyvars free in ds
169 -- See section 9 of static semantics paper for more details.
170 -- (You can get a PhD for explaining the True Meaning
171 -- of this last construct.)
173 placeHolderNames :: NameSet
174 -- Used for the NameSet in FunBind and PatBind prior to the renamer
175 placeHolderNames = panic "placeHolderNames"
178 instance (OutputableBndr idL, OutputableBndr idR) => Outputable (HsLocalBindsLR idL idR) where
179 ppr (HsValBinds bs) = ppr bs
180 ppr (HsIPBinds bs) = ppr bs
181 ppr EmptyLocalBinds = empty
183 instance (OutputableBndr idL, OutputableBndr idR) => Outputable (HsValBindsLR idL idR) where
184 ppr (ValBindsIn binds sigs)
185 = pprValBindsForUser binds sigs
187 ppr (ValBindsOut sccs sigs)
188 = getPprStyle $ \ sty ->
189 if debugStyle sty then -- Print with sccs showing
190 vcat (map ppr sigs) $$ vcat (map ppr_scc sccs)
192 pprValBindsForUser (unionManyBags (map snd sccs)) sigs
194 ppr_scc (rec_flag, binds) = pp_rec rec_flag <+> pprLHsBinds binds
195 pp_rec Recursive = ptext (sLit "rec")
196 pp_rec NonRecursive = ptext (sLit "nonrec")
198 -- *not* pprLHsBinds because we don't want braces; 'let' and
199 -- 'where' include a list of HsBindGroups and we don't want
200 -- several groups of bindings each with braces around.
201 -- Sort by location before printing
202 pprValBindsForUser :: (OutputableBndr idL, OutputableBndr idR, OutputableBndr id2)
203 => LHsBindsLR idL idR -> [LSig id2] -> SDoc
204 pprValBindsForUser binds sigs
205 = pprDeeperList vcat (map snd (sort_by_loc decls))
208 decls :: [(SrcSpan, SDoc)]
209 decls = [(loc, ppr sig) | L loc sig <- sigs] ++
210 [(loc, ppr bind) | L loc bind <- bagToList binds]
212 sort_by_loc decls = sortLe (\(l1,_) (l2,_) -> l1 <= l2) decls
214 pprLHsBinds :: (OutputableBndr idL, OutputableBndr idR) => LHsBindsLR idL idR -> SDoc
216 | isEmptyLHsBinds binds = empty
217 | otherwise = lbrace <+> pprDeeperList vcat (map ppr (bagToList binds)) <+> rbrace
220 emptyLocalBinds :: HsLocalBindsLR a b
221 emptyLocalBinds = EmptyLocalBinds
223 isEmptyLocalBinds :: HsLocalBindsLR a b -> Bool
224 isEmptyLocalBinds (HsValBinds ds) = isEmptyValBinds ds
225 isEmptyLocalBinds (HsIPBinds ds) = isEmptyIPBinds ds
226 isEmptyLocalBinds EmptyLocalBinds = True
228 isEmptyValBinds :: HsValBindsLR a b -> Bool
229 isEmptyValBinds (ValBindsIn ds sigs) = isEmptyLHsBinds ds && null sigs
230 isEmptyValBinds (ValBindsOut ds sigs) = null ds && null sigs
232 emptyValBindsIn, emptyValBindsOut :: HsValBindsLR a b
233 emptyValBindsIn = ValBindsIn emptyBag []
234 emptyValBindsOut = ValBindsOut [] []
236 emptyLHsBinds :: LHsBindsLR idL idR
237 emptyLHsBinds = emptyBag
239 isEmptyLHsBinds :: LHsBindsLR idL idR -> Bool
240 isEmptyLHsBinds = isEmptyBag
243 plusHsValBinds :: HsValBinds a -> HsValBinds a -> HsValBinds a
244 plusHsValBinds (ValBindsIn ds1 sigs1) (ValBindsIn ds2 sigs2)
245 = ValBindsIn (ds1 `unionBags` ds2) (sigs1 ++ sigs2)
246 plusHsValBinds (ValBindsOut ds1 sigs1) (ValBindsOut ds2 sigs2)
247 = ValBindsOut (ds1 ++ ds2) (sigs1 ++ sigs2)
249 getTypeSigNames :: HsValBinds a -> NameSet
250 -- Get the names that have a user type sig
251 getTypeSigNames (ValBindsIn {})
252 = panic "getTypeSigNames"
253 getTypeSigNames (ValBindsOut _ sigs)
254 = mkNameSet [unLoc n | L _ (TypeSig n _) <- sigs]
266 f1p = /\ tvs -> \ [d1,d2] -> letrec DBINDS and BIND
269 gp = ...same again, with gm instead of fm
271 This is a pretty bad translation, because it duplicates all the bindings.
272 So the desugarer tries to do a better job:
274 fp = /\ [a,b] -> \ [d1,d2] -> case tp [a,b] [d1,d2] of
278 tp = /\ [a,b] -> \ [d1,d2] -> letrec DBINDS and BIND
282 instance (OutputableBndr idL, OutputableBndr idR) => Outputable (HsBindLR idL idR) where
283 ppr mbind = ppr_monobind mbind
285 ppr_monobind :: (OutputableBndr idL, OutputableBndr idR) => HsBindLR idL idR -> SDoc
287 ppr_monobind (PatBind { pat_lhs = pat, pat_rhs = grhss })
288 = pprPatBind pat grhss
289 ppr_monobind (VarBind { var_id = var, var_rhs = rhs })
290 = sep [pprBndr CaseBind var, nest 2 $ equals <+> pprExpr (unLoc rhs)]
291 ppr_monobind (FunBind { fun_id = fun, fun_infix = inf,
293 fun_matches = matches,
295 = pprTicks empty (case tick of
297 Just t -> text "-- tick id = " <> ppr t)
298 $$ ifPprDebug (pprBndr LetBind (unLoc fun))
299 $$ pprFunBind (unLoc fun) inf matches
300 $$ ifPprDebug (ppr wrap)
302 ppr_monobind (AbsBinds { abs_tvs = tyvars, abs_ev_vars = dictvars
303 , abs_exports = exports, abs_binds = val_binds
304 , abs_ev_binds = ev_binds })
305 = sep [ptext (sLit "AbsBinds"),
306 brackets (interpp'SP tyvars),
307 brackets (interpp'SP dictvars),
308 brackets (sep (punctuate comma (map ppr_exp exports)))]
310 nest 2 ( vcat [pprBndr LetBind x | (_,x,_,_) <- exports]
311 -- Print type signatures
312 $$ pprLHsBinds val_binds )
314 ifPprDebug (ppr ev_binds)
316 ppr_exp (tvs, gbl, lcl, prags)
317 = vcat [ppr gbl <+> ptext (sLit "<=") <+> ppr tvs <+> ppr lcl,
318 nest 2 (pprTcSpecPrags prags)]
323 pprTicks :: SDoc -> SDoc -> SDoc
324 -- Print stuff about ticks only when -dppr-debug is on, to avoid
325 -- them appearing in error messages (from the desugarer); see Trac # 3263
326 pprTicks pp_no_debug pp_when_debug
327 = getPprStyle (\ sty -> if debugStyle sty then pp_when_debug
331 %************************************************************************
333 Implicit parameter bindings
335 %************************************************************************
341 TcEvBinds -- Only in typechecker output; binds
342 -- uses of the implicit parameters
343 deriving (Data, Typeable)
345 isEmptyIPBinds :: HsIPBinds id -> Bool
346 isEmptyIPBinds (IPBinds is ds) = null is && isEmptyTcEvBinds ds
348 type LIPBind id = Located (IPBind id)
350 -- | Implicit parameter bindings.
355 deriving (Data, Typeable)
357 instance (OutputableBndr id) => Outputable (HsIPBinds id) where
358 ppr (IPBinds bs ds) = pprDeeperList vcat (map ppr bs)
359 $$ ifPprDebug (ppr ds)
361 instance (OutputableBndr id) => Outputable (IPBind id) where
362 ppr (IPBind id rhs) = pprBndr LetBind id <+> equals <+> pprExpr (unLoc rhs)
366 %************************************************************************
368 \subsection{Coercion functions}
370 %************************************************************************
373 -- A HsWrapper is an expression with a hole in it
374 -- We need coercions to have concrete form so that we can zonk them
377 = WpHole -- The identity coercion
379 | WpCompose HsWrapper HsWrapper
380 -- (wrap1 `WpCompse` wrap2)[e] = wrap1[ wrap2[ e ]]
382 -- Hence (\a. []) `WpCompose` (\b. []) = (\a b. [])
383 -- But ([] a) `WpCompose` ([] b) = ([] b a)
385 | WpCast Coercion -- A cast: [] `cast` co
386 -- Guaranteed not the identity coercion
388 -- Evidence abstraction and application
389 -- (both dictionaries and coercions)
390 | WpEvLam EvVar -- \d. [] the 'd' is an evidence variable
391 | WpEvApp EvTerm -- [] d the 'd' is evidence for a constraint
393 -- Type abstraction and application
394 | WpTyLam TyVar -- \a. [] the 'a' is a type variable (not coercion var)
395 | WpTyApp Type -- [] t the 't' is a type (not coercion)
398 | WpLet TcEvBinds -- Non-empty (or possibly non-empty) evidence bindings,
399 -- so that the identity coercion is always exactly WpHole
400 deriving (Data, Typeable)
404 = TcEvBinds -- Mutable evidence bindings
405 EvBindsVar -- Mutable because they are updated "later"
406 -- when an implication constraint is solved
408 | EvBinds -- Immutable after zonking
413 data EvBindsVar = EvBindsVar (IORef EvBindMap) Unique
414 -- The Unique is only for debug printing
417 type EvBindMap = VarEnv EvBind
419 emptyEvBindMap :: EvBindMap
420 emptyEvBindMap = emptyVarEnv
422 extendEvBinds :: EvBindMap -> EvVar -> EvTerm -> EvBindMap
423 extendEvBinds bs v t = extendVarEnv bs v (EvBind v t)
425 lookupEvBind :: EvBindMap -> EvVar -> Maybe EvBind
426 lookupEvBind = lookupVarEnv
428 evBindMapBinds :: EvBindMap -> Bag EvBind
429 evBindMapBinds = foldVarEnv consBag emptyBag
432 instance Data TcEvBinds where
433 -- Placeholder; we can't travers into TcEvBinds
434 toConstr _ = abstractConstr "TcEvBinds"
435 gunfold _ _ = error "gunfold"
436 dataTypeOf _ = mkNoRepType "TcEvBinds"
438 -- All evidence is bound by EvBinds; no side effects
439 data EvBind = EvBind EvVar EvTerm
442 = EvId EvId -- Term-level variable-to-variable bindings
443 -- (no coercion variables! they come via EvCoercion)
445 | EvCoercion Coercion -- Coercion bindings
447 | EvCast EvVar Coercion -- d |> co
449 | EvDFunApp DFunId -- Dictionary instance application
452 | EvSuperClass DictId Int -- n'th superclass. Used for both equalities and
453 -- dictionaries, even though the former have no
454 -- selector Id. We count up from _0_
456 deriving( Data, Typeable)
458 evVarTerm :: EvVar -> EvTerm
459 evVarTerm v | isCoVar v = EvCoercion (mkCoVarCoercion v)
463 Note [EvBinds/EvTerm]
464 ~~~~~~~~~~~~~~~~~~~~~
465 How evidence is created and updated. Bindings for dictionaries,
466 and coercions and implicit parameters are carried around in TcEvBinds
467 which during constraint generation and simplification is always of the
468 form (TcEvBinds ref). After constraint simplification is finished it
469 will be transformed to t an (EvBinds ev_bag).
471 Evidence for coercions *SHOULD* be filled in using the TcEvBinds
472 However, all EvVars that correspond to *wanted* coercion terms in
473 an EvBind must be mutable variables so that they can be readily
474 inlined (by zonking) after constraint simplification is finished.
476 Conclusion: a new wanted coercion variable should be made mutable.
477 [Notice though that evidence variables that bind coercion terms
478 from super classes will be "given" and hence rigid]
482 emptyTcEvBinds :: TcEvBinds
483 emptyTcEvBinds = EvBinds emptyBag
485 isEmptyTcEvBinds :: TcEvBinds -> Bool
486 isEmptyTcEvBinds (EvBinds b) = isEmptyBag b
487 isEmptyTcEvBinds (TcEvBinds {}) = panic "isEmptyTcEvBinds"
489 (<.>) :: HsWrapper -> HsWrapper -> HsWrapper
492 c1 <.> c2 = c1 `WpCompose` c2
494 mkWpTyApps :: [Type] -> HsWrapper
495 mkWpTyApps tys = mk_co_app_fn WpTyApp tys
497 mkWpEvApps :: [EvTerm] -> HsWrapper
498 mkWpEvApps args = mk_co_app_fn WpEvApp args
500 mkWpEvVarApps :: [EvVar] -> HsWrapper
501 mkWpEvVarApps vs = mkWpEvApps (map evVarTerm vs)
503 mkWpTyLams :: [TyVar] -> HsWrapper
504 mkWpTyLams ids = mk_co_lam_fn WpTyLam ids
506 mkWpLams :: [Var] -> HsWrapper
507 mkWpLams ids = mk_co_lam_fn WpEvLam ids
509 mkWpLet :: TcEvBinds -> HsWrapper
510 -- This no-op is a quite a common case
511 mkWpLet (EvBinds b) | isEmptyBag b = WpHole
512 mkWpLet ev_binds = WpLet ev_binds
514 mk_co_lam_fn :: (a -> HsWrapper) -> [a] -> HsWrapper
515 mk_co_lam_fn f as = foldr (\x wrap -> f x `WpCompose` wrap) WpHole as
517 mk_co_app_fn :: (a -> HsWrapper) -> [a] -> HsWrapper
518 -- For applications, the *first* argument must
519 -- come *last* in the composition sequence
520 mk_co_app_fn f as = foldr (\x wrap -> wrap `WpCompose` f x) WpHole as
522 idHsWrapper :: HsWrapper
525 isIdHsWrapper :: HsWrapper -> Bool
526 isIdHsWrapper WpHole = True
527 isIdHsWrapper _ = False
533 instance Outputable HsWrapper where
534 ppr co_fn = pprHsWrapper (ptext (sLit "<>")) co_fn
536 pprHsWrapper :: SDoc -> HsWrapper -> SDoc
537 -- In debug mode, print the wrapper
538 -- otherwise just print what's inside
539 pprHsWrapper doc wrap
540 = getPprStyle (\ s -> if debugStyle s then (help (add_parens doc) wrap False) else doc)
542 help :: (Bool -> SDoc) -> HsWrapper -> Bool -> SDoc
543 -- True <=> appears in function application position
544 -- False <=> appears as body of let or lambda
546 help it (WpCompose f1 f2) = help (help it f2) f1
547 help it (WpCast co) = add_parens $ sep [it False, nest 2 (ptext (sLit "|>")
548 <+> pprParendType co)]
549 help it (WpEvApp id) = no_parens $ sep [it True, nest 2 (ppr id)]
550 help it (WpTyApp ty) = no_parens $ sep [it True, ptext (sLit "@") <+> pprParendType ty]
551 help it (WpEvLam id) = add_parens $ sep [ ptext (sLit "\\") <> pp_bndr id, it False]
552 help it (WpTyLam tv) = add_parens $ sep [ptext (sLit "/\\") <> pp_bndr tv, it False]
553 help it (WpLet binds) = add_parens $ sep [ptext (sLit "let") <+> braces (ppr binds), it False]
555 pp_bndr v = pprBndr LambdaBind v <> dot
557 add_parens, no_parens :: SDoc -> Bool -> SDoc
558 add_parens d True = parens d
559 add_parens d False = d
562 instance Outputable TcEvBinds where
563 ppr (TcEvBinds v) = ppr v
564 ppr (EvBinds bs) = ptext (sLit "EvBinds") <> braces (ppr bs)
566 instance Outputable EvBindsVar where
567 ppr (EvBindsVar _ u) = ptext (sLit "EvBindsVar") <> angleBrackets (ppr u)
569 instance Outputable EvBind where
570 ppr (EvBind v e) = ppr v <+> equals <+> ppr e
572 instance Outputable EvTerm where
574 ppr (EvCast v co) = ppr v <+> (ptext (sLit "`cast`")) <+> pprParendType co
575 ppr (EvCoercion co) = ppr co
576 ppr (EvSuperClass d n) = ptext (sLit "sc") <> parens (ppr (d,n))
577 ppr (EvDFunApp df tys ts) = ppr df <+> sep [ char '@' <> ppr tys
581 %************************************************************************
583 \subsection{@Sig@: type signatures and value-modifying user pragmas}
585 %************************************************************************
587 It is convenient to lump ``value-modifying'' user-pragmas (e.g.,
588 ``specialise this function to these four types...'') in with type
589 signatures. Then all the machinery to move them into place, etc.,
593 type LSig name = Located (Sig name)
595 data Sig name -- Signatures and pragmas
596 = -- An ordinary type signature
597 -- f :: Num a => a -> a
598 TypeSig (Located name) (LHsType name)
600 -- A type signature in generated code, notably the code
601 -- generated for record selectors. We simply record
602 -- the desired Id itself, replete with its name, type
603 -- and IdDetails. Otherwise it's just like a type
604 -- signature: there should be an accompanying binding
607 -- An ordinary fixity declaration
609 | FixSig (FixitySig name)
613 | InlineSig (Located name) -- Function name
614 InlinePragma -- Never defaultInlinePragma
616 -- A specialisation pragma
617 -- {-# SPECIALISE f :: Int -> Int #-}
618 | SpecSig (Located name) -- Specialise a function or datatype ...
619 (LHsType name) -- ... to these types
620 InlinePragma -- The pragma on SPECIALISE_INLINE form
621 -- If it's just defaultInlinePragma, then we said
622 -- SPECIALISE, not SPECIALISE_INLINE
624 -- A specialisation pragma for instance declarations only
625 -- {-# SPECIALISE instance Eq [Int] #-}
626 | SpecInstSig (LHsType name) -- (Class tys); should be a specialisation of the
627 -- current instance decl
628 deriving (Data, Typeable)
631 type LFixitySig name = Located (FixitySig name)
632 data FixitySig name = FixitySig (Located name) Fixity
633 deriving (Data, Typeable)
635 -- TsSpecPrags conveys pragmas from the type checker to the desugarer
637 = IsDefaultMethod -- Super-specialised: a default method should
638 -- be macro-expanded at every call site
639 | SpecPrags [LTcSpecPrag]
640 deriving (Data, Typeable)
642 type LTcSpecPrag = Located TcSpecPrag
646 Id -- The Id to be specialised
647 HsWrapper -- An wrapper, that specialises the polymorphic function
648 InlinePragma -- Inlining spec for the specialised function
649 deriving (Data, Typeable)
651 noSpecPrags :: TcSpecPrags
652 noSpecPrags = SpecPrags []
654 hasSpecPrags :: TcSpecPrags -> Bool
655 hasSpecPrags (SpecPrags ps) = not (null ps)
656 hasSpecPrags IsDefaultMethod = False
658 isDefaultMethod :: TcSpecPrags -> Bool
659 isDefaultMethod IsDefaultMethod = True
660 isDefaultMethod (SpecPrags {}) = False
665 okBindSig :: Sig a -> Bool
668 okHsBootSig :: Sig a -> Bool
669 okHsBootSig (TypeSig _ _) = True
670 okHsBootSig (FixSig _) = True
671 okHsBootSig _ = False
673 okClsDclSig :: Sig a -> Bool
674 okClsDclSig (SpecInstSig _) = False
675 okClsDclSig _ = True -- All others OK
677 okInstDclSig :: Sig a -> Bool
678 okInstDclSig (TypeSig _ _) = False
679 okInstDclSig (FixSig _) = False
680 okInstDclSig _ = True
682 sigForThisGroup :: NameSet -> LSig Name -> Bool
683 sigForThisGroup ns sig
684 = case sigName sig of
686 Just n -> n `elemNameSet` ns
688 sigName :: LSig name -> Maybe name
689 sigName (L _ sig) = sigNameNoLoc sig
691 sigNameNoLoc :: Sig name -> Maybe name
692 sigNameNoLoc (TypeSig n _) = Just (unLoc n)
693 sigNameNoLoc (SpecSig n _ _) = Just (unLoc n)
694 sigNameNoLoc (InlineSig n _) = Just (unLoc n)
695 sigNameNoLoc (FixSig (FixitySig n _)) = Just (unLoc n)
696 sigNameNoLoc _ = Nothing
698 isFixityLSig :: LSig name -> Bool
699 isFixityLSig (L _ (FixSig {})) = True
700 isFixityLSig _ = False
702 isVanillaLSig :: LSig name -> Bool -- User type signatures
703 -- A badly-named function, but it's part of the GHCi (used
704 -- by Haddock) so I don't want to change it gratuitously.
705 isVanillaLSig (L _(TypeSig {})) = True
706 isVanillaLSig _ = False
708 isTypeLSig :: LSig name -> Bool -- Type signatures
709 isTypeLSig (L _(TypeSig {})) = True
710 isTypeLSig (L _(IdSig {})) = True
713 isSpecLSig :: LSig name -> Bool
714 isSpecLSig (L _(SpecSig {})) = True
717 isSpecInstLSig :: LSig name -> Bool
718 isSpecInstLSig (L _ (SpecInstSig {})) = True
719 isSpecInstLSig _ = False
721 isPragLSig :: LSig name -> Bool
722 -- Identifies pragmas
723 isPragLSig (L _ (SpecSig {})) = True
724 isPragLSig (L _ (InlineSig {})) = True
727 isInlineLSig :: LSig name -> Bool
728 -- Identifies inline pragmas
729 isInlineLSig (L _ (InlineSig {})) = True
730 isInlineLSig _ = False
732 hsSigDoc :: Sig name -> SDoc
733 hsSigDoc (TypeSig {}) = ptext (sLit "type signature")
734 hsSigDoc (IdSig {}) = ptext (sLit "id signature")
735 hsSigDoc (SpecSig {}) = ptext (sLit "SPECIALISE pragma")
736 hsSigDoc (InlineSig {}) = ptext (sLit "INLINE pragma")
737 hsSigDoc (SpecInstSig {}) = ptext (sLit "SPECIALISE instance pragma")
738 hsSigDoc (FixSig {}) = ptext (sLit "fixity declaration")
741 Signature equality is used when checking for duplicate signatures
744 eqHsSig :: Eq a => LSig a -> LSig a -> Bool
745 eqHsSig (L _ (FixSig (FixitySig n1 _))) (L _ (FixSig (FixitySig n2 _))) = unLoc n1 == unLoc n2
746 eqHsSig (L _ (IdSig n1)) (L _ (IdSig n2)) = n1 == n2
747 eqHsSig (L _ (TypeSig n1 _)) (L _ (TypeSig n2 _)) = unLoc n1 == unLoc n2
748 eqHsSig (L _ (InlineSig n1 _)) (L _ (InlineSig n2 _)) = unLoc n1 == unLoc n2
749 -- For specialisations, we don't have equality over
750 -- HsType, so it's not convenient to spot duplicate
751 -- specialisations here. Check for this later, when we're in Type land
752 eqHsSig _other1 _other2 = False
756 instance (OutputableBndr name) => Outputable (Sig name) where
757 ppr sig = ppr_sig sig
759 ppr_sig :: OutputableBndr name => Sig name -> SDoc
760 ppr_sig (TypeSig var ty) = pprVarSig (unLoc var) (ppr ty)
761 ppr_sig (IdSig id) = pprVarSig id (ppr (varType id))
762 ppr_sig (FixSig fix_sig) = ppr fix_sig
763 ppr_sig (SpecSig var ty inl) = pragBrackets (pprSpec var (ppr ty) inl)
764 ppr_sig (InlineSig var inl) = pragBrackets (ppr inl <+> ppr var)
765 ppr_sig (SpecInstSig ty) = pragBrackets (ptext (sLit "SPECIALIZE instance") <+> ppr ty)
767 instance Outputable name => Outputable (FixitySig name) where
768 ppr (FixitySig name fixity) = sep [ppr fixity, ppr name]
770 pragBrackets :: SDoc -> SDoc
771 pragBrackets doc = ptext (sLit "{-#") <+> doc <+> ptext (sLit "#-}")
773 pprVarSig :: (Outputable id) => id -> SDoc -> SDoc
774 pprVarSig var pp_ty = sep [ppr var <+> dcolon, nest 2 pp_ty]
776 pprSpec :: (Outputable id) => id -> SDoc -> InlinePragma -> SDoc
777 pprSpec var pp_ty inl = ptext (sLit "SPECIALIZE") <+> pp_inl <+> pprVarSig var pp_ty
779 pp_inl | isDefaultInlinePragma inl = empty
780 | otherwise = ppr inl
782 pprTcSpecPrags :: TcSpecPrags -> SDoc
783 pprTcSpecPrags IsDefaultMethod = ptext (sLit "<default method>")
784 pprTcSpecPrags (SpecPrags ps) = vcat (map (ppr . unLoc) ps)
786 instance Outputable TcSpecPrag where
787 ppr (SpecPrag var _ inl) = pprSpec var (ptext (sLit "<type>")) inl