2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[RnBinds]{Renaming and dependency analysis of bindings}
6 This module does renaming and dependency analysis on value bindings in
7 the abstract syntax. It does {\em not} do cycle-checks on class or
8 type-synonym declarations; those cannot be done at this stage because
9 they may be affected by renaming (which isn't fully worked out yet).
14 rnLocalBindsAndThen, rnValBindsAndThen, rnValBinds, trimWith,
15 rnMethodBinds, renameSigs,
19 #include "HsVersions.h"
21 import {-# SOURCE #-} RnExpr( rnLExpr, rnStmts )
27 import RnTypes ( rnHsSigType, rnLHsType, rnHsTypeFVs,
28 rnLPat, rnPatsAndThen, patSigErr, checkPrecMatch )
29 import RnEnv ( bindLocatedLocalsRn, lookupLocatedBndrRn,
30 lookupLocatedInstDeclBndr, newIPNameRn,
31 lookupLocatedSigOccRn, bindPatSigTyVars, bindPatSigTyVarsFV,
32 bindLocalFixities, bindSigTyVarsFV,
33 warnUnusedLocalBinds, mapFvRn, extendTyVarEnvFVRn,
35 import DynFlags ( DynFlag(..) )
36 import Name ( Name, nameOccName, nameSrcLoc )
39 import PrelNames ( isUnboundName )
40 import RdrName ( RdrName, rdrNameOcc )
41 import SrcLoc ( mkSrcSpan, Located(..), unLoc )
42 import ListSetOps ( findDupsEq )
43 import BasicTypes ( RecFlag(..) )
44 import Digraph ( SCC(..), stronglyConnComp )
47 import Maybes ( orElse, fromJust, isJust )
48 import Monad ( foldM )
51 -- ToDo: Put the annotations into the monad, so that they arrive in the proper
52 -- place and can be used when complaining.
54 The code tree received by the function @rnBinds@ contains definitions
55 in where-clauses which are all apparently mutually recursive, but which may
56 not really depend upon each other. For example, in the top level program
61 the definitions of @a@ and @y@ do not depend on each other at all.
62 Unfortunately, the typechecker cannot always check such definitions.
63 \footnote{Mycroft, A. 1984. Polymorphic type schemes and recursive
64 definitions. In Proceedings of the International Symposium on Programming,
65 Toulouse, pp. 217-39. LNCS 167. Springer Verlag.}
66 However, the typechecker usually can check definitions in which only the
67 strongly connected components have been collected into recursive bindings.
68 This is precisely what the function @rnBinds@ does.
70 ToDo: deal with case where a single monobinds binds the same variable
73 The vertag tag is a unique @Int@; the tags only need to be unique
74 within one @MonoBinds@, so that unique-Int plumbing is done explicitly
75 (heavy monad machinery not needed).
78 %************************************************************************
80 %* naming conventions *
82 %************************************************************************
84 \subsection[name-conventions]{Name conventions}
86 The basic algorithm involves walking over the tree and returning a tuple
87 containing the new tree plus its free variables. Some functions, such
88 as those walking polymorphic bindings (HsBinds) and qualifier lists in
89 list comprehensions (@Quals@), return the variables bound in local
90 environments. These are then used to calculate the free variables of the
91 expression evaluated in these environments.
93 Conventions for variable names are as follows:
96 new code is given a prime to distinguish it from the old.
99 a set of variables defined in @Exp@ is written @dvExp@
102 a set of variables free in @Exp@ is written @fvExp@
105 %************************************************************************
107 %* analysing polymorphic bindings (HsBindGroup, HsBind)
109 %************************************************************************
111 \subsubsection[dep-HsBinds]{Polymorphic bindings}
113 Non-recursive expressions are reconstructed without any changes at top
114 level, although their component expressions may have to be altered.
115 However, non-recursive expressions are currently not expected as
116 \Haskell{} programs, and this code should not be executed.
118 Monomorphic bindings contain information that is returned in a tuple
119 (a @FlatMonoBinds@) containing:
123 a unique @Int@ that serves as the ``vertex tag'' for this binding.
126 the name of a function or the names in a pattern. These are a set
127 referred to as @dvLhs@, the defined variables of the left hand side.
130 the free variables of the body. These are referred to as @fvBody@.
133 the definition's actual code. This is referred to as just @code@.
136 The function @nonRecDvFv@ returns two sets of variables. The first is
137 the set of variables defined in the set of monomorphic bindings, while the
138 second is the set of free variables in those bindings.
140 The set of variables defined in a non-recursive binding is just the
141 union of all of them, as @union@ removes duplicates. However, the
142 free variables in each successive set of cumulative bindings is the
143 union of those in the previous set plus those of the newest binding after
144 the defined variables of the previous set have been removed.
146 @rnMethodBinds@ deals only with the declarations in class and
147 instance declarations. It expects only to see @FunMonoBind@s, and
148 it expects the global environment to contain bindings for the binders
149 (which are all class operations).
151 %************************************************************************
153 \subsubsection{ Top-level bindings}
155 %************************************************************************
157 @rnTopMonoBinds@ assumes that the environment already
158 contains bindings for the binders of this particular binding.
161 rnTopBinds :: HsValBinds RdrName -> RnM (HsValBinds Name, DefUses)
163 -- The binders of the binding are in scope already;
164 -- the top level scope resolution does that
167 = do { is_boot <- tcIsHsBoot
168 ; if is_boot then rnTopBindsBoot binds
169 else rnTopBindsSrc binds }
171 rnTopBindsBoot :: HsValBinds RdrName -> RnM (HsValBinds Name, DefUses)
172 -- A hs-boot file has no bindings.
173 -- Return a single HsBindGroup with empty binds and renamed signatures
174 rnTopBindsBoot (ValBindsIn mbinds sigs)
175 = do { checkErr (isEmptyLHsBinds mbinds) (bindsInHsBootFile mbinds)
176 ; sigs' <- renameSigs okHsBootSig sigs
177 ; return (ValBindsIn emptyLHsBinds sigs', usesOnly (hsSigsFVs sigs')) }
179 rnTopBindsSrc :: HsValBinds RdrName -> RnM (HsValBinds Name, DefUses)
180 rnTopBindsSrc binds@(ValBindsIn mbinds _)
181 = bindPatSigTyVars (collectSigTysFromHsBinds mbinds) $ \ _ ->
182 -- Hmm; by analogy with Ids, this doesn't look right
183 -- Top-level bound type vars should really scope over
184 -- everything, but we only scope them over the other bindings
186 do { (binds', dus) <- rnValBinds noTrim binds
188 -- Warn about missing signatures,
189 ; let { ValBindsOut _ sigs' = binds'
190 ; ty_sig_vars = mkNameSet [ unLoc n | L _ (Sig n _) <- sigs']
191 ; un_sigd_bndrs = duDefs dus `minusNameSet` ty_sig_vars }
193 ; warn_missing_sigs <- doptM Opt_WarnMissingSigs
194 ; ifM (warn_missing_sigs)
195 (mappM_ missingSigWarn (nameSetToList un_sigd_bndrs))
197 ; return (binds', dus)
203 %*********************************************************
207 %*********************************************************
211 :: HsLocalBinds RdrName
212 -> (HsLocalBinds Name -> RnM (result, FreeVars))
213 -> RnM (result, FreeVars)
214 -- This version (a) assumes that the binding vars are not already in scope
215 -- (b) removes the binders from the free vars of the thing inside
216 -- The parser doesn't produce ThenBinds
217 rnLocalBindsAndThen EmptyLocalBinds thing_inside
218 = thing_inside EmptyLocalBinds
220 rnLocalBindsAndThen (HsValBinds val_binds) thing_inside
221 = rnValBindsAndThen val_binds $ \ val_binds' ->
222 thing_inside (HsValBinds val_binds')
224 rnLocalBindsAndThen (HsIPBinds binds) thing_inside
225 = rnIPBinds binds `thenM` \ (binds',fv_binds) ->
226 thing_inside (HsIPBinds binds') `thenM` \ (thing, fvs_thing) ->
227 returnM (thing, fvs_thing `plusFV` fv_binds)
230 rnIPBinds (IPBinds ip_binds _no_dict_binds)
231 = do { (ip_binds', fvs_s) <- mapAndUnzipM (wrapLocFstM rnIPBind) ip_binds
232 ; return (IPBinds ip_binds' emptyLHsBinds, plusFVs fvs_s) }
234 rnIPBind (IPBind n expr)
235 = newIPNameRn n `thenM` \ name ->
236 rnLExpr expr `thenM` \ (expr',fvExpr) ->
237 return (IPBind name expr', fvExpr)
241 %************************************************************************
245 %************************************************************************
248 rnValBindsAndThen :: HsValBinds RdrName
249 -> (HsValBinds Name -> RnM (result, FreeVars))
250 -> RnM (result, FreeVars)
252 rnValBindsAndThen binds@(ValBindsIn mbinds sigs) thing_inside
253 = -- Extract all the binders in this group, and extend the
254 -- current scope, inventing new names for the new binders
255 -- This also checks that the names form a set
256 bindLocatedLocalsRn doc mbinders_w_srclocs $ \ bndrs ->
257 bindPatSigTyVarsFV (collectSigTysFromHsBinds mbinds) $
259 -- Then install local fixity declarations
260 -- Notice that they scope over thing_inside too
261 bindLocalFixities [sig | L _ (FixSig sig) <- sigs ] $
264 rnValBinds (trimWith bndrs) binds `thenM` \ (binds, bind_dus) ->
266 -- Now do the "thing inside"
267 thing_inside binds `thenM` \ (result,result_fvs) ->
269 -- Final error checking
271 all_uses = duUses bind_dus `plusFV` result_fvs
272 -- duUses: It's important to return all the uses, not the 'real uses'
273 -- used for warning about unused bindings. Otherwise consider:
275 -- y = let p = x in 'x' -- NB: p not used
276 -- If we don't "see" the dependency of 'y' on 'x', we may put the
277 -- bindings in the wrong order, and the type checker will complain
278 -- that x isn't in scope
280 unused_bndrs = [ b | b <- bndrs, not (b `elemNameSet` all_uses)]
282 warnUnusedLocalBinds unused_bndrs `thenM_`
284 returnM (result, delListFromNameSet all_uses bndrs)
286 mbinders_w_srclocs = collectHsBindLocatedBinders mbinds
287 doc = text "In the binding group for:"
288 <+> pprWithCommas ppr (map unLoc mbinders_w_srclocs)
290 ---------------------
291 rnValBinds :: (FreeVars -> FreeVars)
292 -> HsValBinds RdrName
293 -> RnM (HsValBinds Name, DefUses)
294 -- Assumes the binders of the binding are in scope already
296 rnValBinds trim (ValBindsIn mbinds sigs)
297 = do { sigs' <- rename_sigs sigs
299 ; binds_w_dus <- mapBagM (rnBind (mkSigTvFn sigs') trim) mbinds
301 ; let (binds', bind_dus) = depAnalBinds binds_w_dus
303 -- We do the check-sigs after renaming the bindings,
304 -- so that we have convenient access to the binders
305 ; check_sigs (okBindSig (duDefs bind_dus)) sigs'
307 ; return (ValBindsOut binds' sigs',
308 usesOnly (hsSigsFVs sigs') `plusDU` bind_dus) }
311 ---------------------
312 depAnalBinds :: Bag (LHsBind Name, [Name], Uses)
313 -> ([(RecFlag, LHsBinds Name)], DefUses)
314 -- Dependency analysis; this is important so that
315 -- unused-binding reporting is accurate
316 depAnalBinds binds_w_dus
317 = (map get_binds sccs, map get_du sccs)
319 sccs = stronglyConnComp edges
321 keyd_nodes = bagToList binds_w_dus `zip` [0::Int ..]
323 edges = [ (node, key, [fromJust mb_key | n <- nameSetToList uses,
324 let mb_key = lookupNameEnv key_map n,
326 | (node@(_,_,uses), key) <- keyd_nodes ]
328 key_map :: NameEnv Int -- Which binding it comes from
329 key_map = mkNameEnv [(bndr, key) | ((_, bndrs, _), key) <- keyd_nodes
332 get_binds (AcyclicSCC (bind, _, _)) = (NonRecursive, unitBag bind)
333 get_binds (CyclicSCC binds_w_dus) = (Recursive, listToBag [b | (b,d,u) <- binds_w_dus])
335 get_du (AcyclicSCC (_, bndrs, uses)) = (Just (mkNameSet bndrs), uses)
336 get_du (CyclicSCC binds_w_dus) = (Just defs, uses)
338 defs = mkNameSet [b | (_,bs,_) <- binds_w_dus, b <- bs]
339 uses = unionManyNameSets [u | (_,_,u) <- binds_w_dus]
342 ---------------------
343 -- Bind the top-level forall'd type variables in the sigs.
346 -- The 'a' scopes over the rhs
348 -- NB: there'll usually be just one (for a function binding)
349 -- but if there are many, one may shadow the rest; too bad!
350 -- e.g x :: [a] -> [a]
353 -- In e, 'a' will be in scope, and it'll be the one from 'y'!
355 mkSigTvFn :: [LSig Name] -> (Name -> [Name])
356 -- Return a lookup function that maps an Id Name to the names
357 -- of the type variables that should scope over its body..
359 = \n -> lookupNameEnv env n `orElse` []
361 env :: NameEnv [Name]
362 env = mkNameEnv [ (name, map hsLTyVarName ltvs)
363 | L _ (Sig (L _ name)
364 (L _ (HsForAllTy Explicit ltvs _ _))) <- sigs]
365 -- Note the pattern-match on "Explicit"; we only bind
366 -- type variables from signatures with an explicit top-level for-all
368 -- The trimming function trims the free vars we attach to a
369 -- binding so that it stays reasonably small
370 noTrim :: FreeVars -> FreeVars
371 noTrim fvs = fvs -- Used at top level
373 trimWith :: [Name] -> FreeVars -> FreeVars
374 -- Nested bindings; trim by intersection with the names bound here
375 trimWith bndrs = intersectNameSet (mkNameSet bndrs)
377 ---------------------
378 rnBind :: (Name -> [Name]) -- Signature tyvar function
379 -> (FreeVars -> FreeVars) -- Trimming function for rhs free vars
381 -> RnM (LHsBind Name, [Name], Uses)
382 rnBind sig_fn trim (L loc (PatBind pat grhss ty _))
384 do { (pat', pat_fvs) <- rnLPat pat
386 ; let bndrs = collectPatBinders pat'
388 ; (grhss', fvs) <- bindSigTyVarsFV (concatMap sig_fn bndrs) $
389 rnGRHSs PatBindRhs grhss
391 ; return (L loc (PatBind pat' grhss' ty (trim fvs)), bndrs, pat_fvs `plusFV` fvs) }
393 rnBind sig_fn trim (L loc (FunBind name inf matches _))
395 do { new_name <- lookupLocatedBndrRn name
396 ; let plain_name = unLoc new_name
398 ; (matches', fvs) <- bindSigTyVarsFV (sig_fn plain_name) $
399 rnMatchGroup (FunRhs plain_name) matches
401 ; checkPrecMatch inf plain_name matches'
403 ; return (L loc (FunBind new_name inf matches' (trim fvs)), [plain_name], fvs)
408 @rnMethodBinds@ is used for the method bindings of a class and an instance
409 declaration. Like @rnBinds@ but without dependency analysis.
411 NOTA BENE: we record each {\em binder} of a method-bind group as a free variable.
412 That's crucial when dealing with an instance decl:
414 instance Foo (T a) where
417 This might be the {\em sole} occurrence of @op@ for an imported class @Foo@,
418 and unless @op@ occurs we won't treat the type signature of @op@ in the class
419 decl for @Foo@ as a source of instance-decl gates. But we should! Indeed,
420 in many ways the @op@ in an instance decl is just like an occurrence, not
424 rnMethodBinds :: Name -- Class name
425 -> [Name] -- Names for generic type variables
427 -> RnM (LHsBinds Name, FreeVars)
429 rnMethodBinds cls gen_tyvars binds
430 = foldM do_one (emptyBag,emptyFVs) (bagToList binds)
431 where do_one (binds,fvs) bind = do
432 (bind', fvs_bind) <- rnMethodBind cls gen_tyvars bind
433 return (bind' `unionBags` binds, fvs_bind `plusFV` fvs)
435 rnMethodBind cls gen_tyvars (L loc (FunBind name inf (MatchGroup matches _) _))
437 lookupLocatedInstDeclBndr cls name `thenM` \ sel_name ->
438 let plain_name = unLoc sel_name in
439 -- We use the selector name as the binder
441 mapFvRn (rn_match plain_name) matches `thenM` \ (new_matches, fvs) ->
443 new_group = MatchGroup new_matches placeHolderType
445 checkPrecMatch inf plain_name new_group `thenM_`
446 returnM (unitBag (L loc (FunBind sel_name inf new_group fvs)), fvs `addOneFV` plain_name)
447 -- The 'fvs' field isn't used for method binds
449 -- Truly gruesome; bring into scope the correct members of the generic
450 -- type variables. See comments in RnSource.rnSourceDecl(ClassDecl)
451 rn_match sel_name match@(L _ (Match (L _ (TypePat ty) : _) _ _))
452 = extendTyVarEnvFVRn gen_tvs $
453 rnMatch (FunRhs sel_name) match
455 tvs = map (rdrNameOcc.unLoc) (extractHsTyRdrTyVars ty)
456 gen_tvs = [tv | tv <- gen_tyvars, nameOccName tv `elem` tvs]
458 rn_match sel_name match = rnMatch (FunRhs sel_name) match
461 -- Can't handle method pattern-bindings which bind multiple methods.
462 rnMethodBind cls gen_tyvars mbind@(L loc (PatBind other_pat _ _ _))
463 = addLocErr mbind methodBindErr `thenM_`
464 returnM (emptyBag, emptyFVs)
468 %************************************************************************
470 \subsubsection[dep-Sigs]{Signatures (and user-pragmas for values)}
472 %************************************************************************
474 @renameSigs@ checks for:
476 \item more than one sig for one thing;
477 \item signatures given for things not bound here;
478 \item with suitably flaggery, that all top-level things have type signatures.
481 At the moment we don't gather free-var info from the types in
482 signatures. We'd only need this if we wanted to report unused tyvars.
485 renameSigs :: (LSig Name -> Bool) -> [LSig RdrName] -> RnM [LSig Name]
486 -- Renames the signatures and performs error checks
487 renameSigs ok_sig sigs
488 = do { sigs' <- rename_sigs sigs
489 ; check_sigs ok_sig sigs'
492 ----------------------
493 rename_sigs :: [LSig RdrName] -> RnM [LSig Name]
494 rename_sigs sigs = mappM (wrapLocM renameSig)
495 (filter (not . isFixityLSig) sigs)
496 -- Remove fixity sigs which have been dealt with already
498 ----------------------
499 check_sigs :: (LSig Name -> Bool) -> [LSig Name] -> RnM ()
500 -- Used for class and instance decls, as well as regular bindings
501 check_sigs ok_sig sigs
502 -- Check for (a) duplicate signatures
503 -- (b) signatures for things not in this group
504 = do { mappM_ unknownSigErr (filter bad sigs)
505 ; mappM_ dupSigDeclErr (findDupsEq eqHsSig sigs) }
507 -- Don't complain about an unbound name again
508 bad sig = not (ok_sig sig) &&
510 Just n | isUnboundName n -> False
513 -- We use lookupLocatedSigOccRn in the signatures, which is a little bit unsatisfactory
514 -- because this won't work for:
515 -- instance Foo T where
518 -- We'll just rename the INLINE prag to refer to whatever other 'op'
519 -- is in scope. (I'm assuming that Baz.op isn't in scope unqualified.)
520 -- Doesn't seem worth much trouble to sort this.
522 renameSig :: Sig RdrName -> RnM (Sig Name)
523 -- FixitSig is renamed elsewhere.
525 = lookupLocatedSigOccRn v `thenM` \ new_v ->
526 rnHsSigType (quotes (ppr v)) ty `thenM` \ new_ty ->
527 returnM (Sig new_v new_ty)
529 renameSig (SpecInstSig ty)
530 = rnLHsType (text "A SPECIALISE instance pragma") ty `thenM` \ new_ty ->
531 returnM (SpecInstSig new_ty)
533 renameSig (SpecSig v ty)
534 = lookupLocatedSigOccRn v `thenM` \ new_v ->
535 rnHsSigType (quotes (ppr v)) ty `thenM` \ new_ty ->
536 returnM (SpecSig new_v new_ty)
538 renameSig (InlineSig b v p)
539 = lookupLocatedSigOccRn v `thenM` \ new_v ->
540 returnM (InlineSig b new_v p)
544 ************************************************************************
548 ************************************************************************
551 rnMatchGroup :: HsMatchContext Name -> MatchGroup RdrName -> RnM (MatchGroup Name, FreeVars)
552 rnMatchGroup ctxt (MatchGroup ms _)
553 = mapFvRn (rnMatch ctxt) ms `thenM` \ (new_ms, ms_fvs) ->
554 returnM (MatchGroup new_ms placeHolderType, ms_fvs)
556 rnMatch :: HsMatchContext Name -> LMatch RdrName -> RnM (LMatch Name, FreeVars)
557 rnMatch ctxt = wrapLocFstM (rnMatch' ctxt)
559 rnMatch' ctxt match@(Match pats maybe_rhs_sig grhss)
561 -- Deal with the rhs type signature
562 bindPatSigTyVarsFV rhs_sig_tys $
563 doptM Opt_GlasgowExts `thenM` \ opt_GlasgowExts ->
564 (case maybe_rhs_sig of
565 Nothing -> returnM (Nothing, emptyFVs)
566 Just ty | opt_GlasgowExts -> rnHsTypeFVs doc_sig ty `thenM` \ (ty', ty_fvs) ->
567 returnM (Just ty', ty_fvs)
568 | otherwise -> addLocErr ty patSigErr `thenM_`
569 returnM (Nothing, emptyFVs)
570 ) `thenM` \ (maybe_rhs_sig', ty_fvs) ->
572 -- Now the main event
573 rnPatsAndThen ctxt pats $ \ pats' ->
574 rnGRHSs ctxt grhss `thenM` \ (grhss', grhss_fvs) ->
576 returnM (Match pats' maybe_rhs_sig' grhss', grhss_fvs `plusFV` ty_fvs)
577 -- The bindPatSigTyVarsFV and rnPatsAndThen will remove the bound FVs
579 rhs_sig_tys = case maybe_rhs_sig of
582 doc_sig = text "In a result type-signature"
586 %************************************************************************
588 \subsubsection{Guarded right-hand sides (GRHSs)}
590 %************************************************************************
593 rnGRHSs :: HsMatchContext Name -> GRHSs RdrName -> RnM (GRHSs Name, FreeVars)
595 rnGRHSs ctxt (GRHSs grhss binds)
596 = rnLocalBindsAndThen binds $ \ binds' ->
597 mapFvRn (rnGRHS ctxt) grhss `thenM` \ (grhss', fvGRHSs) ->
598 returnM (GRHSs grhss' binds', fvGRHSs)
600 rnGRHS :: HsMatchContext Name -> LGRHS RdrName -> RnM (LGRHS Name, FreeVars)
601 rnGRHS ctxt = wrapLocFstM (rnGRHS' ctxt)
603 rnGRHS' ctxt (GRHS guards rhs)
604 = do { opt_GlasgowExts <- doptM Opt_GlasgowExts
605 ; checkM (opt_GlasgowExts || is_standard_guard guards)
606 (addWarn (nonStdGuardErr guards))
608 ; ((guards', rhs'), fvs) <- rnStmts (PatGuard ctxt) guards $
610 ; return (GRHS guards' rhs', fvs) }
612 -- Standard Haskell 1.4 guards are just a single boolean
613 -- expression, rather than a list of qualifiers as in the
615 is_standard_guard [] = True
616 is_standard_guard [L _ (ExprStmt _ _ _)] = True
617 is_standard_guard other = False
620 %************************************************************************
622 \subsection{Error messages}
624 %************************************************************************
627 dupSigDeclErr sigs@(L loc sig : _)
629 vcat [ptext SLIT("Duplicate") <+> what_it_is <> colon,
630 nest 2 (vcat (map ppr_sig sigs))]
632 what_it_is = hsSigDoc sig
633 ppr_sig (L loc sig) = ppr loc <> colon <+> ppr sig
635 unknownSigErr (L loc sig)
637 sep [ptext SLIT("Misplaced") <+> what_it_is <> colon, ppr sig]
639 what_it_is = hsSigDoc sig
642 = addWarnAt (mkSrcSpan loc loc) $
643 sep [ptext SLIT("Definition but no type signature for"), quotes (ppr var)]
645 loc = nameSrcLoc var -- TODO: make a proper span
648 = hang (ptext SLIT("Pattern bindings (except simple variables) not allowed in instance declarations"))
651 bindsInHsBootFile mbinds
652 = hang (ptext SLIT("Bindings in hs-boot files are not allowed"))
657 SLIT("accepting non-standard pattern guards (-fglasgow-exts to suppress this message)")