%
-% (c) The GRASP/AQUA Project, Glasgow University, 1992-1996
+% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
%
\section[HsBinds]{Abstract syntax: top-level bindings and signatures}
Datatype for: @HsBinds@, @Bind@, @Sig@, @MonoBinds@.
\begin{code}
-#include "HsVersions.h"
-
module HsBinds where
-IMP_Ubiq()
+#include "HsVersions.h"
+
+import {-# SOURCE #-} HsExpr ( pprExpr, HsExpr )
+import {-# SOURCE #-} HsMatches ( pprMatches, Match, pprGRHSs, GRHSs )
-- friends:
-IMPORT_DELOOPER(HsLoop)
-import HsMatches ( pprMatches, pprGRHSsAndBinds,
- Match, GRHSsAndBinds )
-import HsPat ( collectPatBinders, InPat )
-import HsPragmas ( GenPragmas, ClassOpPragmas )
-import HsTypes ( PolyType )
+import HsTypes ( HsType, cmpHsType )
+import HsImpExp ( IE(..), ieName )
+import CoreSyn ( CoreExpr )
+import PprCore () -- Instances for Outputable
--others:
-import Id ( DictVar(..), Id(..), GenId )
-import Name ( pprNonSym )
-import Outputable ( interpp'SP, ifnotPprForUser,
- Outputable(..){-instance * (,)-}
- )
-import Pretty
-import SrcLoc ( SrcLoc{-instances-} )
---import TyVar ( GenTyVar{-instances-} )
+import Id ( Id )
+import Name ( Name, isUnboundName )
+import NameSet ( NameSet, elemNameSet, nameSetToList )
+import BasicTypes ( RecFlag(..), Fixity )
+import Outputable
+import Bag
+import SrcLoc ( SrcLoc )
+import Var ( TyVar )
+import Util ( thenCmp )
\end{code}
%************************************************************************
Collections of bindings, created by dependency analysis and translation:
\begin{code}
-data HsBinds tyvar uvar id pat -- binders and bindees
+data HsBinds id pat -- binders and bindees
= EmptyBinds
- | ThenBinds (HsBinds tyvar uvar id pat)
- (HsBinds tyvar uvar id pat)
+ | ThenBinds (HsBinds id pat)
+ (HsBinds id pat)
+
+ | MonoBind (MonoBinds id pat)
+ [Sig id] -- Empty on typechecker output
+ RecFlag
+\end{code}
+
+\begin{code}
+nullBinds :: HsBinds id pat -> Bool
+
+nullBinds EmptyBinds = True
+nullBinds (ThenBinds b1 b2) = nullBinds b1 && nullBinds b2
+nullBinds (MonoBind b _ _) = nullMonoBinds b
+
+mkMonoBind :: MonoBinds id pat -> [Sig id] -> RecFlag -> HsBinds id pat
+mkMonoBind EmptyMonoBinds _ _ = EmptyBinds
+mkMonoBind mbinds sigs is_rec = MonoBind mbinds sigs is_rec
+\end{code}
+
+\begin{code}
+instance (Outputable pat, Outputable id) =>
+ Outputable (HsBinds id pat) where
+ ppr binds = ppr_binds binds
+
+ppr_binds EmptyBinds = empty
+ppr_binds (ThenBinds binds1 binds2)
+ = ($$) (ppr_binds binds1) (ppr_binds binds2)
+ppr_binds (MonoBind bind sigs is_rec)
+ = vcat [ifNotPprForUser (ptext rec_str),
+ vcat (map ppr sigs),
+ ppr bind
+ ]
+ where
+ rec_str = case is_rec of
+ Recursive -> SLIT("{- rec -}")
+ NonRecursive -> SLIT("{- nonrec -}")
+\end{code}
- | SingleBind (Bind tyvar uvar id pat)
+%************************************************************************
+%* *
+\subsection{Bindings: @MonoBinds@}
+%* *
+%************************************************************************
- | BindWith -- Bind with a type signature.
- -- These appear only on typechecker input
- -- (PolyType [in Sigs] can't appear on output)
- (Bind tyvar uvar id pat)
- [Sig id]
+Global bindings (where clauses)
- | AbsBinds -- Binds abstraction; TRANSLATION
- [tyvar]
- [id] -- Dicts
- [(id, id)] -- (old, new) pairs
- [(id, HsExpr tyvar uvar id pat)] -- local dictionaries
- (Bind tyvar uvar id pat) -- "the business end"
+\begin{code}
+data MonoBinds id pat
+ = EmptyMonoBinds
+
+ | AndMonoBinds (MonoBinds id pat)
+ (MonoBinds id pat)
+
+ | FunMonoBind id -- Used for both functions f x = e
+ -- and variables f = \x -> e
+ -- Reason: the Match stuff lets us have an optional
+ -- result type sig f :: a->a = ...mentions a...
+ Bool -- True => infix declaration
+ [Match id pat]
+ SrcLoc
+
+ | PatMonoBind pat -- The pattern is never a simple variable;
+ -- That case is done by FunMonoBind
+ (GRHSs id pat)
+ SrcLoc
+
+ | VarMonoBind id -- TRANSLATION
+ (HsExpr id pat)
+
+ | CoreMonoBind id -- TRANSLATION
+ CoreExpr -- No zonking; this is a final CoreExpr with Ids and Types!
+
+ | AbsBinds -- Binds abstraction; TRANSLATION
+ [TyVar] -- Type variables
+ [id] -- Dicts
+ [([TyVar], id, id)] -- (type variables, polymorphic, momonmorphic) triples
+ NameSet -- Set of *polymorphic* variables that have an INLINE pragma
+ (MonoBinds id pat) -- The "business end"
-- Creates bindings for *new* (polymorphic, overloaded) locals
-- in terms of *old* (monomorphic, non-overloaded) ones.
-- of this last construct.)
\end{code}
+What AbsBinds means
+~~~~~~~~~~~~~~~~~~~
+ AbsBinds tvs
+ [d1,d2]
+ [(tvs1, f1p, f1m),
+ (tvs2, f2p, f2m)]
+ BIND
+means
+
+ f1p = /\ tvs -> \ [d1,d2] -> letrec DBINDS and BIND
+ in fm
+
+ gp = ...same again, with gm instead of fm
+
+This is a pretty bad translation, because it duplicates all the bindings.
+So the desugarer tries to do a better job:
+
+ fp = /\ [a,b] -> \ [d1,d2] -> case tp [a,b] [d1,d2] of
+ (fm,gm) -> fm
+ ..ditto for gp..
+
+ p = /\ [a,b] -> \ [d1,d2] -> letrec DBINDS and BIND
+ in (fm,gm)
+
\begin{code}
-nullBinds :: HsBinds tyvar uvar id pat -> Bool
+-- We keep the invariant that a MonoBinds is only empty
+-- if it is exactly EmptyMonoBinds
-nullBinds EmptyBinds = True
-nullBinds (ThenBinds b1 b2) = nullBinds b1 && nullBinds b2
-nullBinds (SingleBind b) = nullBind b
-nullBinds (BindWith b _) = nullBind b
-nullBinds (AbsBinds _ _ _ ds b) = null ds && nullBind b
+nullMonoBinds :: MonoBinds id pat -> Bool
+nullMonoBinds EmptyMonoBinds = True
+nullMonoBinds other_monobind = False
+
+andMonoBinds :: MonoBinds id pat -> MonoBinds id pat -> MonoBinds id pat
+andMonoBinds EmptyMonoBinds mb = mb
+andMonoBinds mb EmptyMonoBinds = mb
+andMonoBinds mb1 mb2 = AndMonoBinds mb1 mb2
+
+andMonoBindList :: [MonoBinds id pat] -> MonoBinds id pat
+andMonoBindList binds
+ = loop1 binds
+ where
+ loop1 [] = EmptyMonoBinds
+ loop1 (EmptyMonoBinds : binds) = loop1 binds
+ loop1 (b:bs) = loop2 b bs
+
+ -- acc is non-empty
+ loop2 acc [] = acc
+ loop2 acc (EmptyMonoBinds : bs) = loop2 acc bs
+ loop2 acc (b:bs) = loop2 (acc `AndMonoBinds` b) bs
\end{code}
+
\begin{code}
-instance (Outputable pat, NamedThing id, Outputable id,
- Eq tyvar, Outputable tyvar, Eq uvar, Outputable uvar) =>
- Outputable (HsBinds tyvar uvar id pat) where
-
- ppr sty EmptyBinds = ppNil
- ppr sty (ThenBinds binds1 binds2)
- = ppAbove (ppr sty binds1) (ppr sty binds2)
- ppr sty (SingleBind bind) = ppr sty bind
- ppr sty (BindWith bind sigs)
- = ppAbove (if null sigs
- then ppNil
- else ppAboves (map (ppr sty) sigs))
- (ppr sty bind)
- ppr sty (AbsBinds tyvars dictvars local_pairs dict_binds val_binds)
- = ppAbove (ppSep [ppPStr SLIT("AbsBinds"),
- ppBesides[ppLbrack, interpp'SP sty tyvars, ppRbrack],
- ppBesides[ppLbrack, interpp'SP sty dictvars, ppRbrack],
- ppBesides[ppLbrack, interpp'SP sty local_pairs, ppRbrack]])
- (ppNest 4 (ppAbove (ppAboves (map (ppr sty) dict_binds)) (ppr sty val_binds)))
+instance (Outputable id, Outputable pat) =>
+ Outputable (MonoBinds id pat) where
+ ppr mbind = ppr_monobind mbind
+
+
+ppr_monobind :: (Outputable id, Outputable pat) => MonoBinds id pat -> SDoc
+ppr_monobind EmptyMonoBinds = empty
+ppr_monobind (AndMonoBinds binds1 binds2)
+ = ppr_monobind binds1 $$ ppr_monobind binds2
+
+ppr_monobind (PatMonoBind pat grhss locn)
+ = sep [ppr pat, nest 4 (pprGRHSs False grhss)]
+
+ppr_monobind (FunMonoBind fun inf matches locn)
+ = pprMatches (False, ppr fun) matches
+ -- ToDo: print infix if appropriate
+
+ppr_monobind (VarMonoBind name expr)
+ = sep [ppr name <+> equals, nest 4 (pprExpr expr)]
+
+ppr_monobind (CoreMonoBind name expr)
+ = sep [ppr name <+> equals, nest 4 (ppr expr)]
+
+ppr_monobind (AbsBinds tyvars dictvars exports inlines val_binds)
+ = sep [ptext SLIT("AbsBinds"),
+ brackets (interpp'SP tyvars),
+ brackets (interpp'SP dictvars),
+ brackets (sep (punctuate comma (map ppr exports))),
+ brackets (interpp'SP (nameSetToList inlines))]
+ $$
+ nest 4 (ppr val_binds)
\end{code}
%************************************************************************
\begin{code}
data Sig name
= Sig name -- a bog-std type signature
- (PolyType name)
- (GenPragmas name) -- only interface ones have pragmas
+ (HsType name)
SrcLoc
- | ClassOpSig name -- class-op sigs have different pragmas
- (PolyType name)
- (ClassOpPragmas name) -- only interface ones have pragmas
+ | ClassOpSig name -- Selector name
+ name -- Default-method name (if any)
+ Bool -- True <=> there is an explicit, programmer-supplied
+ -- default declaration in the class decl
+ (HsType name)
SrcLoc
| SpecSig name -- specialise a function or datatype ...
- (PolyType name) -- ... to these types
- (Maybe name) -- ... maybe using this as the code for it
+ (HsType name) -- ... to these types
SrcLoc
- | InlineSig name -- INLINE f
+ | InlineSig name -- INLINE f
+ (Maybe Int) -- phase
SrcLoc
- -- ToDo: strictly speaking, could omit based on -DOMIT_DEFORESTER
- | DeforestSig name -- Deforest using this function definition
- SrcLoc
+ | NoInlineSig name -- NOINLINE f
+ (Maybe Int) -- phase
+ SrcLoc
+
+ | SpecInstSig (HsType name) -- (Class tys); should be a specialisation of the
+ -- current instance decl
+ SrcLoc
+
+ | FixSig (FixitySig name) -- Fixity declaration
+
+ | DeprecSig (Deprecation name) -- DEPRECATED
+ SrcLoc
- | MagicUnfoldingSig
- name -- Associate the "name"d function with
- FAST_STRING -- the compiler-builtin unfolding (known
- SrcLoc -- by the String name)
+data FixitySig name = FixitySig name Fixity SrcLoc
+
+-- We use exported entities for things to deprecate. Cunning trick (hack?):
+-- `IEModuleContents undefined' is used for module deprecation.
+data Deprecation name = Deprecation (IE name) DeprecTxt
+
+type DeprecTxt = FAST_STRING -- reason/explanation for deprecation
\end{code}
\begin{code}
-instance (NamedThing name, Outputable name) => Outputable (Sig name) where
- ppr sty (Sig var ty pragmas _)
- = ppHang (ppCat [pprNonSym sty var, ppPStr SLIT("::")])
- 4 (ppHang (ppr sty ty)
- 4 (ifnotPprForUser sty (ppr sty pragmas)))
-
- ppr sty (ClassOpSig var ty pragmas _)
- = ppHang (ppCat [pprNonSym sty var, ppPStr SLIT("::")])
- 4 (ppHang (ppr sty ty)
- 4 (ifnotPprForUser sty (ppr sty pragmas)))
-
- ppr sty (DeforestSig var _)
- = ppHang (ppCat [ppStr "{-# DEFOREST", pprNonSym sty var])
- 4 (ppStr "#-}")
-
- ppr sty (SpecSig var ty using _)
- = ppHang (ppCat [ppPStr SLIT("{-# SPECIALIZE"), pprNonSym sty var, ppPStr SLIT("::")])
- 4 (ppCat [ppr sty ty, pp_using using, ppPStr SLIT("#-}")])
- where
- pp_using Nothing = ppNil
- pp_using (Just me) = ppCat [ppChar '=', ppr sty me]
-
- ppr sty (InlineSig var _)
- = ppCat [ppPStr SLIT("{-# INLINE"), pprNonSym sty var, ppPStr SLIT("#-}")]
-
- ppr sty (MagicUnfoldingSig var str _)
- = ppCat [ppPStr SLIT("{-# MAGIC_UNFOLDING"), pprNonSym sty var, ppPStr str, ppPStr SLIT("#-}")]
+okBindSig :: NameSet -> Sig Name -> Bool
+okBindSig ns (ClassOpSig _ _ _ _ _) = False
+okBindSig ns sig = sigForThisGroup ns sig
+
+okClsDclSig :: NameSet -> Sig Name -> Bool
+okClsDclSig ns (Sig _ _ _) = False
+okClsDclSig ns sig = sigForThisGroup ns sig
+
+okInstDclSig :: NameSet -> Sig Name -> Bool
+okInstDclSig ns (Sig _ _ _) = False
+okInstDclSig ns (FixSig _) = False
+okInstDclSig ns (SpecInstSig _ _) = True
+okInstDclSig ns sig = sigForThisGroup ns sig
+
+sigForThisGroup ns sig
+ = case sigName sig of
+ Nothing -> False
+ Just n | isUnboundName n -> True -- Don't complain about an unbound name again
+ | otherwise -> n `elemNameSet` ns
+
+sigsForMe :: (name -> Bool) -> [Sig name] -> [Sig name]
+sigsForMe f sigs
+ = filter sig_for_me sigs
+ where
+ sig_for_me sig = case sigName sig of
+ Nothing -> False
+ Just n -> f n
+
+sigName :: Sig name -> Maybe name
+sigName (Sig n _ _) = Just n
+sigName (ClassOpSig n _ _ _ _) = Just n
+sigName (SpecSig n _ _) = Just n
+sigName (InlineSig n _ _) = Just n
+sigName (NoInlineSig n _ _) = Just n
+sigName (FixSig (FixitySig n _ _)) = Just n
+sigName (DeprecSig (Deprecation d _) _) = case d of
+ IEModuleContents _ -> Nothing
+ other -> Just (ieName d)
+sigName other = Nothing
+
+isFixitySig :: Sig name -> Bool
+isFixitySig (FixSig _) = True
+isFixitySig _ = False
+
+isClassOpSig :: Sig name -> Bool
+isClassOpSig (ClassOpSig _ _ _ _ _) = True
+isClassOpSig _ = False
+
+isPragSig :: Sig name -> Bool
+ -- Identifies pragmas
+isPragSig (SpecSig _ _ _) = True
+isPragSig (InlineSig _ _ _) = True
+isPragSig (NoInlineSig _ _ _) = True
+isPragSig (SpecInstSig _ _) = True
+isPragSig (DeprecSig _ _) = True
+isPragSig other = False
\end{code}
-%************************************************************************
-%* *
-\subsection{Binding: @Bind@}
-%* *
-%************************************************************************
-
\begin{code}
-data Bind tyvar uvar id pat -- binders and bindees
- = EmptyBind -- because it's convenient when parsing signatures
- | NonRecBind (MonoBinds tyvar uvar id pat)
- | RecBind (MonoBinds tyvar uvar id pat)
+hsSigDoc (Sig _ _ loc) = (SLIT("type signature"),loc)
+hsSigDoc (ClassOpSig _ _ _ _ loc) = (SLIT("class-method type signature"), loc)
+hsSigDoc (SpecSig _ _ loc) = (SLIT("SPECIALISE pragma"),loc)
+hsSigDoc (InlineSig _ _ loc) = (SLIT("INLINE pragma"),loc)
+hsSigDoc (NoInlineSig _ _ loc) = (SLIT("NOINLINE pragma"),loc)
+hsSigDoc (SpecInstSig _ loc) = (SLIT("SPECIALISE instance pragma"),loc)
+hsSigDoc (FixSig (FixitySig _ _ loc)) = (SLIT("fixity declaration"), loc)
+hsSigDoc (DeprecSig _ loc) = (SLIT("DEPRECATED pragma"), loc)
\end{code}
\begin{code}
-nullBind :: Bind tyvar uvar id pat -> Bool
+instance (Outputable name) => Outputable (Sig name) where
+ ppr sig = ppr_sig sig
-nullBind EmptyBind = True
-nullBind (NonRecBind bs) = nullMonoBinds bs
-nullBind (RecBind bs) = nullMonoBinds bs
-\end{code}
+ppr_sig :: Outputable name => Sig name -> SDoc
+ppr_sig (Sig var ty _)
+ = sep [ppr var <+> dcolon, nest 4 (ppr ty)]
-\begin{code}
-bindIsRecursive :: Bind tyvar uvar id pat -> Bool
+ppr_sig (ClassOpSig var _ _ ty _)
+ = sep [ppr var <+> dcolon, nest 4 (ppr ty)]
-bindIsRecursive EmptyBind = False
-bindIsRecursive (NonRecBind _) = False
-bindIsRecursive (RecBind _) = True
-\end{code}
+ppr_sig (SpecSig var ty _)
+ = sep [ hsep [text "{-# SPECIALIZE", ppr var, dcolon],
+ nest 4 (ppr ty <+> text "#-}")
+ ]
-\begin{code}
-instance (NamedThing id, Outputable id, Outputable pat,
- Eq tyvar, Outputable tyvar, Eq uvar, Outputable uvar) =>
- Outputable (Bind tyvar uvar id pat) where
- ppr sty EmptyBind = ppNil
- ppr sty (NonRecBind binds)
- = ppAbove (ifnotPprForUser sty (ppStr "{- nonrec -}"))
- (ppr sty binds)
- ppr sty (RecBind binds)
- = ppAbove (ifnotPprForUser sty (ppStr "{- rec -}"))
- (ppr sty binds)
-\end{code}
+ppr_sig (InlineSig var phase _)
+ = hsep [text "{-# INLINE", ppr_phase phase, ppr var, text "#-}"]
-%************************************************************************
-%* *
-\subsection{Bindings: @MonoBinds@}
-%* *
-%************************************************************************
+ppr_sig (NoInlineSig var phase _)
+ = hsep [text "{-# NOINLINE", ppr_phase phase, ppr var, text "#-}"]
-Global bindings (where clauses)
+ppr_sig (SpecInstSig ty _)
+ = hsep [text "{-# SPECIALIZE instance", ppr ty, text "#-}"]
-\begin{code}
-data MonoBinds tyvar uvar id pat
- = EmptyMonoBinds
- | AndMonoBinds (MonoBinds tyvar uvar id pat)
- (MonoBinds tyvar uvar id pat)
- | PatMonoBind pat
- (GRHSsAndBinds tyvar uvar id pat)
- SrcLoc
- | FunMonoBind id
- Bool -- True => infix declaration
- [Match tyvar uvar id pat] -- must have at least one Match
- SrcLoc
- | VarMonoBind id -- TRANSLATION
- (HsExpr tyvar uvar id pat)
-\end{code}
+ppr_sig (FixSig fix_sig) = ppr fix_sig
-\begin{code}
-nullMonoBinds :: MonoBinds tyvar uvar id pat -> Bool
+ppr_sig (DeprecSig deprec _) = ppr deprec
-nullMonoBinds EmptyMonoBinds = True
-nullMonoBinds (AndMonoBinds bs1 bs2) = nullMonoBinds bs1 && nullMonoBinds bs2
-nullMonoBinds other_monobind = False
-\end{code}
+instance Outputable name => Outputable (FixitySig name) where
+ ppr (FixitySig name fixity loc) = sep [ppr fixity, ppr name]
-\begin{code}
-instance (NamedThing id, Outputable id, Outputable pat,
- Eq tyvar, Outputable tyvar, Eq uvar, Outputable uvar) =>
- Outputable (MonoBinds tyvar uvar id pat) where
- ppr sty EmptyMonoBinds = ppNil
- ppr sty (AndMonoBinds binds1 binds2)
- = ppAbove (ppr sty binds1) (ppr sty binds2)
-
- ppr sty (PatMonoBind pat grhss_n_binds locn)
- = ppHang (ppr sty pat) 4 (pprGRHSsAndBinds sty False grhss_n_binds)
-
- ppr sty (FunMonoBind fun inf matches locn)
- = pprMatches sty (False, pprNonSym sty fun) matches
- -- ToDo: print infix if appropriate
+instance Outputable name => Outputable (Deprecation name) where
+ ppr (Deprecation (IEModuleContents _) txt)
+ = hsep [text "{-# DEPRECATED", doubleQuotes (ppr txt), text "#-}"]
+ ppr (Deprecation thing txt)
+ = hsep [text "{-# DEPRECATED", ppr thing, doubleQuotes (ppr txt), text "#-}"]
- ppr sty (VarMonoBind name expr)
- = ppHang (ppCat [pprNonSym sty name, ppEquals]) 4 (ppr sty expr)
+ppr_phase :: Maybe Int -> SDoc
+ppr_phase Nothing = empty
+ppr_phase (Just n) = int n
\end{code}
-%************************************************************************
-%* *
-\subsection{Collecting binders from @HsBinds@}
-%* *
-%************************************************************************
+Checking for distinct signatures; oh, so boring
-Get all the binders in some @MonoBinds@, IN THE ORDER OF
-APPEARANCE; e.g., in:
-\begin{verbatim}
-...
-where
- (x, y) = ...
- f i j = ...
- [a, b] = ...
-\end{verbatim}
-it should return @[x, y, f, a, b]@ (remember, order important).
\begin{code}
-collectTopLevelBinders :: HsBinds tyvar uvar name (InPat name) -> [name]
-collectTopLevelBinders EmptyBinds = []
-collectTopLevelBinders (SingleBind b) = collectBinders b
-collectTopLevelBinders (BindWith b _) = collectBinders b
-collectTopLevelBinders (ThenBinds b1 b2)
- = collectTopLevelBinders b1 ++ collectTopLevelBinders b2
-
-collectBinders :: Bind tyvar uvar name (InPat name) -> [name]
-collectBinders EmptyBind = []
-collectBinders (NonRecBind monobinds) = collectMonoBinders monobinds
-collectBinders (RecBind monobinds) = collectMonoBinders monobinds
-
-collectMonoBinders :: MonoBinds tyvar uvar name (InPat name) -> [name]
-collectMonoBinders EmptyMonoBinds = []
-collectMonoBinders (PatMonoBind pat grhss_w_binds _) = collectPatBinders pat
-collectMonoBinders (FunMonoBind f _ matches _) = [f]
-collectMonoBinders (VarMonoBind v expr) = error "collectMonoBinders"
-collectMonoBinders (AndMonoBinds bs1 bs2)
- = collectMonoBinders bs1 ++ collectMonoBinders bs2
-
--- We'd like the binders -- and where they came from --
--- so we can make new ones with equally-useful origin info.
-
-collectMonoBindersAndLocs
- :: MonoBinds tyvar uvar name (InPat name) -> [(name, SrcLoc)]
-
-collectMonoBindersAndLocs EmptyMonoBinds = []
-
-collectMonoBindersAndLocs (AndMonoBinds bs1 bs2)
- = collectMonoBindersAndLocs bs1 ++ collectMonoBindersAndLocs bs2
-
-collectMonoBindersAndLocs (PatMonoBind pat grhss_w_binds locn)
- = collectPatBinders pat `zip` repeat locn
-
-collectMonoBindersAndLocs (FunMonoBind f _ matches locn) = [(f, locn)]
-
-#ifdef DEBUG
-collectMonoBindersAndLocs (VarMonoBind v expr)
- = trace "collectMonoBindersAndLocs:VarMonoBind" []
- -- ToDo: this is dubious, i.e., wrong, but harmless?
-#endif
+cmpHsSig :: Sig Name -> Sig Name -> Ordering
+cmpHsSig (Sig n1 _ _) (Sig n2 _ _) = n1 `compare` n2
+cmpHsSig (DeprecSig (Deprecation ie1 _) _)
+ (DeprecSig (Deprecation ie2 _) _) = cmp_ie ie1 ie2
+cmpHsSig (InlineSig n1 _ _) (InlineSig n2 _ _) = n1 `compare` n2
+cmpHsSig (NoInlineSig n1 _ _) (NoInlineSig n2 _ _) = n1 `compare` n2
+
+cmpHsSig (SpecInstSig ty1 _) (SpecInstSig ty2 _) = cmpHsType compare ty1 ty2
+cmpHsSig (SpecSig n1 ty1 _) (SpecSig n2 ty2 _)
+ = -- may have many specialisations for one value;
+ -- but not ones that are exactly the same...
+ thenCmp (n1 `compare` n2) (cmpHsType compare ty1 ty2)
+
+cmpHsSig other_1 other_2 -- Tags *must* be different
+ | (sig_tag other_1) _LT_ (sig_tag other_2) = LT
+ | otherwise = GT
+
+cmp_ie :: IE Name -> IE Name -> Ordering
+cmp_ie (IEVar n1 ) (IEVar n2 ) = n1 `compare` n2
+cmp_ie (IEThingAbs n1 ) (IEThingAbs n2 ) = n1 `compare` n2
+cmp_ie (IEThingAll n1 ) (IEThingAll n2 ) = n1 `compare` n2
+-- Hmmm...
+cmp_ie (IEThingWith n1 _) (IEThingWith n2 _) = n1 `compare` n2
+cmp_ie (IEModuleContents _ ) (IEModuleContents _ ) = EQ
+
+sig_tag (Sig n1 _ _) = (ILIT(1) :: FAST_INT)
+sig_tag (SpecSig n1 _ _) = ILIT(2)
+sig_tag (InlineSig n1 _ _) = ILIT(3)
+sig_tag (NoInlineSig n1 _ _) = ILIT(4)
+sig_tag (SpecInstSig _ _) = ILIT(5)
+sig_tag (FixSig _) = ILIT(6)
+sig_tag (DeprecSig _ _) = ILIT(7)
+sig_tag _ = panic# "tag(RnBinds)"
\end{code}