2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[RnMonad]{The monad used by the renamer}
10 module RdrName, -- Re-exports
11 module Name, -- from these two
24 #include "HsVersions.h"
26 #if defined(__GLASGOW_HASKELL__) && __GLASGOW_HASKELL__ >= 405
27 import IOExts ( fixIO )
28 #elif defined(__GLASGOW_HASKELL__) && __GLASGOW_HASKELL__ >= 302
29 import PrelIOBase ( fixIO ) -- Should be in GlaExts
31 import IOBase ( fixIO )
33 import IOExts ( IORef, newIORef, readIORef, writeIORef, unsafePerformIO )
34 import IO ( hPutStr, stderr )
38 import RnHsSyn ( RenamedFixitySig )
39 import HscTypes ( AvailEnv, emptyAvailEnv, lookupType,
41 ImportedModuleInfo, WhetherHasOrphans, ImportVersion,
42 PersistentRenamerState(..), Avails,
43 DeclsMap, IfaceInsts, IfaceRules,
44 HomeSymbolTable, TyThing,
45 PersistentCompilerState(..), GlobalRdrEnv, LocalRdrEnv,
46 HomeIfaceTable, PackageIfaceTable,
48 import BasicTypes ( Version, defaultFixity )
49 import ErrUtils ( addShortErrLocLine, addShortWarnLocLine,
50 Message, Messages, errorsFound, warningsFound,
51 printErrorsAndWarnings
53 import RdrName ( RdrName, dummyRdrVarName, rdrNameModule, rdrNameOcc,
54 RdrNameEnv, emptyRdrEnv, extendRdrEnv,
55 addListToRdrEnv, rdrEnvToList, rdrEnvElts
57 import Name ( Name, OccName, NamedThing(..),
59 decode, mkLocalName, mkKnownKeyGlobal
61 import NameEnv ( NameEnv, lookupNameEnv, emptyNameEnv, extendNameEnvList )
62 import Module ( Module, ModuleName, ModuleSet, emptyModuleSet )
64 import CmdLineOpts ( DynFlags, DynFlag(..), dopt )
65 import SrcLoc ( SrcLoc, generatedSrcLoc, noSrcLoc )
66 import Unique ( Unique )
67 import FiniteMap ( FiniteMap )
68 import Maybes ( seqMaybe )
69 import Bag ( Bag, emptyBag, isEmptyBag, snocBag )
72 import PrelNames ( mkUnboundName )
74 infixr 9 `thenRn`, `thenRn_`
78 %************************************************************************
80 \subsection{Somewhat magical interface to other monads}
82 %************************************************************************
85 ioToRnM :: IO r -> RnM d (Either IOError r)
86 ioToRnM io rn_down g_down = (io >>= \ ok -> return (Right ok))
88 (\ err -> return (Left err))
90 ioToRnM_no_fail :: IO r -> RnM d r
91 ioToRnM_no_fail io rn_down g_down
92 = (io >>= \ ok -> return ok)
94 (\ err -> panic "ioToRnM_no_fail: the I/O operation failed!")
96 traceRn :: SDoc -> RnM d ()
97 traceRn msg = ifOptRn Opt_D_dump_rn_trace (putDocRn msg)
99 traceHiDiffsRn :: SDoc -> RnM d ()
100 traceHiDiffsRn msg = ifOptRn Opt_D_dump_hi_diffs (putDocRn msg)
102 putDocRn :: SDoc -> RnM d ()
103 putDocRn msg = ioToRnM (printErrs alwaysQualify msg) `thenRn_`
108 %************************************************************************
110 \subsection{Data types}
112 %************************************************************************
114 %===================================================
115 \subsubsection{ MONAD TYPES}
116 %===================================================
119 type RnM d r = RnDown -> d -> IO r
120 type RnMS r = RnM SDown r -- Renaming source
121 type RnMG r = RnM () r -- Getting global names etc
126 rn_mod :: Module, -- This module
127 rn_loc :: SrcLoc, -- Current locn
129 rn_dflags :: DynFlags,
131 rn_hit :: HomeIfaceTable,
132 rn_done :: Name -> Maybe TyThing, -- Tells what things (both in the
133 -- home package and other packages)
134 -- were already available (i.e. in
135 -- the relevant SymbolTable) before
136 -- compiling this module
137 -- The Name passed to rn_done is guaranteed to be a Global,
138 -- so it has a Module, so it can be looked up
140 rn_errs :: IORef Messages,
141 rn_ns :: IORef NameSupply,
142 rn_ifaces :: IORef Ifaces
145 -- For renaming source code
149 rn_genv :: GlobalRdrEnv, -- Top level environment
151 rn_avails :: AvailEnv,
152 -- Top level AvailEnv; contains all the things that
153 -- are nameable in the top-level scope, regardless of
154 -- *how* they can be named (qualified, unqualified...)
155 -- It is used only to map a Class to its class ops, and
156 -- hence to resolve the binders in an instance decl
158 rn_lenv :: LocalRdrEnv, -- Local name envt
159 -- Does *not* include global name envt; may shadow it
160 -- Includes both ordinary variables and type variables;
161 -- they are kept distinct because tyvar have a different
162 -- occurrence contructor (Name.TvOcc)
163 -- We still need the unsullied global name env so that
164 -- we can look up record field names
166 rn_fixenv :: LocalFixityEnv -- Local fixities (for non-top-level
168 -- The global fixities are held in the
169 -- HIT or PIT. Why? See the comments
170 -- with RnIfaces.lookupLocalFixity
173 data RnMode = SourceMode -- Renaming source code
174 | InterfaceMode -- Renaming interface declarations.
175 | CmdLineMode -- Renaming a command-line expression
177 isInterfaceMode InterfaceMode = True
178 isInterfaceMode _ = False
180 isCmdLineMode CmdLineMode = True
181 isCmdLineMode _ = False
184 %===================================================
185 \subsubsection{ ENVIRONMENTS}
186 %===================================================
189 --------------------------------
190 type LocalFixityEnv = NameEnv RenamedFixitySig
191 -- We keep the whole fixity sig so that we
192 -- can report line-number info when there is a duplicate
193 -- fixity declaration
195 emptyLocalFixityEnv :: LocalFixityEnv
196 emptyLocalFixityEnv = emptyNameEnv
198 lookupLocalFixity :: LocalFixityEnv -> Name -> Fixity
199 lookupLocalFixity env name
200 = case lookupNameEnv env name of
201 Just (FixitySig _ fix _) -> fix
202 Nothing -> defaultFixity
206 type ExportAvails = (FiniteMap ModuleName Avails,
207 -- Used to figure out "module M" export specifiers
208 -- Includes avails only from *unqualified* imports
209 -- (see 1.4 Report Section 5.1.1)
211 AvailEnv) -- Used to figure out all other export specifiers.
214 %===================================================
215 \subsubsection{ INTERFACE FILE STUFF}
216 %===================================================
219 type ExportItem = (ModuleName, [RdrAvailInfo])
220 type IfaceDeprecs = Maybe (Either DeprecTxt [(RdrName,DeprecTxt)])
221 -- Nothing => NoDeprecs
222 -- Just (Left t) => DeprecAll
223 -- Just (Right p) => DeprecSome
227 pi_mod :: Module, -- Complete with package info
228 pi_vers :: Version, -- Module version number
229 pi_orphan :: WhetherHasOrphans, -- Whether this module has orphans
230 pi_usages :: [ImportVersion OccName], -- Usages
231 pi_exports :: (Version, [ExportItem]), -- Exports
232 pi_decls :: [(Version, RdrNameTyClDecl)], -- Local definitions
233 pi_fixity :: [RdrNameFixitySig], -- Local fixity declarations,
234 pi_insts :: [RdrNameInstDecl], -- Local instance declarations
235 pi_rules :: (Version, [RdrNameRuleDecl]), -- Rules, with their version
236 pi_deprecs :: IfaceDeprecs -- Deprecations
240 %************************************************************************
242 \subsection{The renamer state}
244 %************************************************************************
247 data Ifaces = Ifaces {
249 iPIT :: PackageIfaceTable,
250 -- The ModuleIFaces for modules in other packages
251 -- whose interfaces we have opened
252 -- The declarations in these interface files are held in
253 -- iDecls, iInsts, iRules (below), not in the mi_decls fields
254 -- of the iPIT. What _is_ in the iPIT is:
260 -- The iPIT field is initialised from the compiler's persistent
261 -- package symbol table, and the renamer incrementally adds
264 iImpModInfo :: ImportedModuleInfo,
265 -- Modules that we know something about, because they are mentioned
266 -- in interface files, BUT which we have not loaded yet.
267 -- No module is both in here and in the PIT
270 -- A single, global map of Names to unslurped decls
272 iInsts :: IfaceInsts,
273 -- The as-yet un-slurped instance decls; this bag is depleted when we
274 -- slurp an instance decl so that we don't slurp the same one twice.
275 -- Each is 'gated' by the names that must be available before
276 -- this instance decl is needed.
278 iRules :: IfaceRules,
279 -- Similar to instance decls, only for rules
282 -- These fields persist during the compilation of a single module only
284 -- All the names (whether "big" or "small", whether wired-in or not,
285 -- whether locally defined or not) that have been slurped in so far.
287 -- It's used for two things:
288 -- a) To record what we've already slurped, so
289 -- we can no-op if we try to slurp it again
290 -- b) As the 'gates' for importing rules. We import a rule
291 -- if all its LHS free vars have been slurped
293 iVSlurp :: (ModuleSet, NameSet)
294 -- The Names are all the (a) non-wired-in
296 -- (c) non-locally-defined
298 -- names that have been slurped in so far, with their versions.
299 -- This is used to generate the "usage" information for this module.
300 -- Subset of the previous field.
302 -- The module set is the non-home-package modules from which we have
303 -- slurped at least one name.
304 -- It's worth keeping separately, because there's no very easy
305 -- way to distinguish the "big" names from the "non-big" ones.
306 -- But this is a decision we might want to revisit.
311 %************************************************************************
313 \subsection{Main monad code}
315 %************************************************************************
318 runRn dflags hit hst pcs mod do_rn
319 = do { (pcs, msgs, r) <- initRn dflags hit hst pcs mod do_rn ;
320 printErrorsAndWarnings alwaysQualify msgs ;
321 return (pcs, errorsFound msgs, r)
325 -> HomeIfaceTable -> HomeSymbolTable
326 -> PersistentCompilerState
329 -> IO (PersistentCompilerState, Messages, t)
331 initRn dflags hit hst pcs mod do_rn
333 let prs = pcs_PRS pcs
334 let pte = pcs_PTE pcs
335 let ifaces = Ifaces { iPIT = pcs_PIT pcs,
336 iDecls = prsDecls prs,
337 iInsts = prsInsts prs,
338 iRules = prsRules prs,
340 iImpModInfo = prsImpMods prs,
341 iSlurp = unitNameSet (mkUnboundName dummyRdrVarName),
342 -- Pretend that the dummy unbound name has already been
343 -- slurped. This is what's returned for an out-of-scope name,
344 -- and we don't want thereby to try to suck it in!
345 iVSlurp = (emptyModuleSet, emptyNameSet)
347 names_var <- newIORef (prsOrig prs)
348 errs_var <- newIORef (emptyBag,emptyBag)
349 iface_var <- newIORef ifaces
350 let rn_down = RnDown { rn_mod = mod,
355 rn_done = lookupType hst pte,
359 rn_ifaces = iface_var,
363 res <- do_rn rn_down ()
365 -- Grab state and record it
366 (warns, errs) <- readIORef errs_var
367 new_ifaces <- readIORef iface_var
368 new_orig <- readIORef names_var
369 let new_prs = prs { prsOrig = new_orig,
370 prsImpMods = iImpModInfo new_ifaces,
371 prsDecls = iDecls new_ifaces,
372 prsInsts = iInsts new_ifaces,
373 prsRules = iRules new_ifaces }
374 let new_pcs = pcs { pcs_PIT = iPIT new_ifaces,
377 return (new_pcs, (warns, errs), res)
379 initRnMS :: GlobalRdrEnv -> AvailEnv -> LocalRdrEnv -> LocalFixityEnv -> RnMode
382 initRnMS rn_env avails local_env fixity_env mode thing_inside rn_down g_down
383 -- The fixity_env appears in both the rn_fixenv field
384 -- and in the HIT. See comments with RnHiFiles.lookupFixityRn
386 s_down = SDown { rn_genv = rn_env, rn_avails = avails,
387 rn_lenv = local_env, rn_fixenv = fixity_env,
390 thing_inside rn_down s_down
392 initIfaceRnMS :: Module -> RnMS r -> RnM d r
393 initIfaceRnMS mod thing_inside
394 = initRnMS emptyRdrEnv emptyAvailEnv emptyRdrEnv
395 emptyLocalFixityEnv InterfaceMode
396 (setModuleRn mod thing_inside)
399 @renameDerivedCode@ is used to rename stuff ``out-of-line'';
400 that is, not as part of the main renamer.
401 Sole examples: derived definitions,
402 which are only generated in the type checker.
404 The @NameSupply@ includes a @UniqueSupply@, so if you call it more than
405 once you must either split it, or install a fresh unique supply.
408 renameDerivedCode :: DynFlags
410 -> PersistentRenamerState
414 renameDerivedCode dflags mod prs thing_inside
416 -- It's not really unsafe! When renaming source code we
417 -- only do any I/O if we need to read in a fixity declaration;
418 -- and that doesn't happen in pragmas etc
420 do { us <- mkSplitUniqSupply 'r'
421 ; names_var <- newIORef ((prsOrig prs) { nsUniqs = us })
422 ; errs_var <- newIORef (emptyBag,emptyBag)
424 ; let rn_down = RnDown { rn_dflags = dflags,
425 rn_loc = generatedSrcLoc, rn_ns = names_var,
428 rn_done = bogus "rn_done",
429 rn_hit = bogus "rn_hit",
430 rn_ifaces = bogus "rn_ifaces"
432 ; let s_down = SDown { rn_mode = InterfaceMode,
433 -- So that we can refer to PrelBase.True etc
434 rn_avails = emptyAvailEnv,
435 rn_genv = emptyRdrEnv, rn_lenv = emptyRdrEnv,
436 rn_fixenv = emptyLocalFixityEnv }
438 ; result <- thing_inside rn_down s_down
439 ; messages <- readIORef errs_var
441 ; if bad messages then
442 do { hPutStr stderr "Urk! renameDerivedCode found errors or warnings"
443 ; printErrorsAndWarnings alwaysQualify messages
452 bad messages = errorsFound messages || warningsFound messages
454 bad messages = errorsFound messages
457 bogus s = panic ("rnameSourceCode: " ++ s) -- Used for unused record fields
459 {-# INLINE thenRn #-}
460 {-# INLINE thenRn_ #-}
461 {-# INLINE returnRn #-}
464 returnRn :: a -> RnM d a
465 thenRn :: RnM d a -> (a -> RnM d b) -> RnM d b
466 thenRn_ :: RnM d a -> RnM d b -> RnM d b
467 andRn :: (a -> a -> a) -> RnM d a -> RnM d a -> RnM d a
468 mapRn :: (a -> RnM d b) -> [a] -> RnM d [b]
469 mapRn_ :: (a -> RnM d b) -> [a] -> RnM d ()
470 mapMaybeRn :: (a -> RnM d (Maybe b)) -> [a] -> RnM d [b]
471 flatMapRn :: (a -> RnM d [b]) -> [a] -> RnM d [b]
472 sequenceRn :: [RnM d a] -> RnM d [a]
473 sequenceRn_ :: [RnM d a] -> RnM d ()
474 foldlRn :: (b -> a -> RnM d b) -> b -> [a] -> RnM d b
475 mapAndUnzipRn :: (a -> RnM d (b,c)) -> [a] -> RnM d ([b],[c])
476 fixRn :: (a -> RnM d a) -> RnM d a
478 returnRn v gdown ldown = return v
479 thenRn m k gdown ldown = m gdown ldown >>= \ r -> k r gdown ldown
480 thenRn_ m k gdown ldown = m gdown ldown >> k gdown ldown
481 fixRn m gdown ldown = fixIO (\r -> m r gdown ldown)
482 andRn combiner m1 m2 gdown ldown
483 = m1 gdown ldown >>= \ res1 ->
484 m2 gdown ldown >>= \ res2 ->
485 return (combiner res1 res2)
487 sequenceRn [] = returnRn []
488 sequenceRn (m:ms) = m `thenRn` \ r ->
489 sequenceRn ms `thenRn` \ rs ->
492 sequenceRn_ [] = returnRn ()
493 sequenceRn_ (m:ms) = m `thenRn_` sequenceRn_ ms
495 mapRn f [] = returnRn []
497 = f x `thenRn` \ r ->
498 mapRn f xs `thenRn` \ rs ->
501 mapRn_ f [] = returnRn ()
506 foldlRn k z [] = returnRn z
507 foldlRn k z (x:xs) = k z x `thenRn` \ z' ->
510 mapAndUnzipRn f [] = returnRn ([],[])
511 mapAndUnzipRn f (x:xs)
512 = f x `thenRn` \ (r1, r2) ->
513 mapAndUnzipRn f xs `thenRn` \ (rs1, rs2) ->
514 returnRn (r1:rs1, r2:rs2)
516 mapAndUnzip3Rn f [] = returnRn ([],[],[])
517 mapAndUnzip3Rn f (x:xs)
518 = f x `thenRn` \ (r1, r2, r3) ->
519 mapAndUnzip3Rn f xs `thenRn` \ (rs1, rs2, rs3) ->
520 returnRn (r1:rs1, r2:rs2, r3:rs3)
522 mapMaybeRn f [] = returnRn []
523 mapMaybeRn f (x:xs) = f x `thenRn` \ maybe_r ->
524 mapMaybeRn f xs `thenRn` \ rs ->
526 Nothing -> returnRn rs
527 Just r -> returnRn (r:rs)
529 flatMapRn f [] = returnRn []
530 flatMapRn f (x:xs) = f x `thenRn` \ r ->
531 flatMapRn f xs `thenRn` \ rs ->
537 %************************************************************************
539 \subsection{Boring plumbing for common part}
541 %************************************************************************
545 \subsubsection{ Errors and warnings}
546 %=====================
549 failWithRn :: a -> Message -> RnM d a
550 failWithRn res msg (RnDown {rn_errs = errs_var, rn_loc = loc}) l_down
551 = readIORef errs_var >>= \ (warns,errs) ->
552 writeIORef errs_var (warns, errs `snocBag` err) >>
555 err = addShortErrLocLine loc msg
557 warnWithRn :: a -> Message -> RnM d a
558 warnWithRn res msg (RnDown {rn_errs = errs_var, rn_loc = loc}) l_down
559 = readIORef errs_var >>= \ (warns,errs) ->
560 writeIORef errs_var (warns `snocBag` warn, errs) >>
563 warn = addShortWarnLocLine loc msg
565 tryRn :: RnM d a -> RnM d (Either Messages a)
566 tryRn try_this down@(RnDown {rn_errs = errs_var}) l_down
567 = do current_msgs <- readIORef errs_var
568 writeIORef errs_var (emptyBag,emptyBag)
569 a <- try_this down l_down
570 (warns, errs) <- readIORef errs_var
571 writeIORef errs_var current_msgs
573 then return (Right a)
574 else return (Left (warns,errs))
576 setErrsRn :: Messages -> RnM d ()
577 setErrsRn msgs down@(RnDown {rn_errs = errs_var}) l_down
578 = do writeIORef errs_var msgs; return ()
580 addErrRn :: Message -> RnM d ()
581 addErrRn err = failWithRn () err
583 checkRn :: Bool -> Message -> RnM d () -- Check that a condition is true
584 checkRn False err = addErrRn err
585 checkRn True err = returnRn ()
587 warnCheckRn :: Bool -> Message -> RnM d () -- Check that a condition is true
588 warnCheckRn False err = addWarnRn err
589 warnCheckRn True err = returnRn ()
591 addWarnRn :: Message -> RnM d ()
592 addWarnRn warn = warnWithRn () warn
594 checkErrsRn :: RnM d Bool -- True <=> no errors so far
595 checkErrsRn (RnDown {rn_errs = errs_var}) l_down
596 = readIORef errs_var >>= \ (warns,errs) ->
597 return (isEmptyBag errs)
599 doptRn :: DynFlag -> RnM d Bool
600 doptRn dflag (RnDown { rn_dflags = dflags}) l_down
601 = return (dopt dflag dflags)
603 ifOptRn :: DynFlag -> RnM d a -> RnM d ()
604 ifOptRn dflag thing_inside down@(RnDown { rn_dflags = dflags}) l_down
605 | dopt dflag dflags = thing_inside down l_down >> return ()
606 | otherwise = return ()
608 getDOptsRn :: RnM d DynFlags
609 getDOptsRn (RnDown { rn_dflags = dflags}) l_down
615 \subsubsection{Source location}
616 %=====================
619 pushSrcLocRn :: SrcLoc -> RnM d a -> RnM d a
620 pushSrcLocRn loc' m down l_down
621 = m (down {rn_loc = loc'}) l_down
623 getSrcLocRn :: RnM d SrcLoc
624 getSrcLocRn down l_down
625 = return (rn_loc down)
629 \subsubsection{The finder and home symbol table}
630 %=====================
633 getHomeIfaceTableRn :: RnM d HomeIfaceTable
634 getHomeIfaceTableRn down l_down = return (rn_hit down)
636 getTypeEnvRn :: RnM d (Name -> Maybe TyThing)
637 getTypeEnvRn down l_down = return (rn_done down)
639 extendTypeEnvRn :: NameEnv TyThing -> RnM d a -> RnM d a
640 extendTypeEnvRn env inside down l_down
641 = inside down{rn_done=new_rn_done} l_down
642 where new_rn_done = \nm -> lookupNameEnv env nm `seqMaybe` rn_done down nm
646 \subsubsection{Name supply}
647 %=====================
650 getNameSupplyRn :: RnM d NameSupply
651 getNameSupplyRn rn_down l_down
652 = readIORef (rn_ns rn_down)
654 setNameSupplyRn :: NameSupply -> RnM d ()
655 setNameSupplyRn names' (RnDown {rn_ns = names_var}) l_down
656 = writeIORef names_var names'
658 getUniqRn :: RnM d Unique
659 getUniqRn (RnDown {rn_ns = names_var}) l_down
660 = readIORef names_var >>= \ ns ->
662 (us1,us') = splitUniqSupply (nsUniqs ns)
664 writeIORef names_var (ns {nsUniqs = us'}) >>
665 return (uniqFromSupply us1)
669 \subsubsection{ Module}
670 %=====================
673 getModuleRn :: RnM d Module
674 getModuleRn (RnDown {rn_mod = mod}) l_down
677 setModuleRn :: Module -> RnM d a -> RnM d a
678 setModuleRn new_mod enclosed_thing rn_down l_down
679 = enclosed_thing (rn_down {rn_mod = new_mod}) l_down
683 %************************************************************************
685 \subsection{Plumbing for rename-source part}
687 %************************************************************************
690 \subsubsection{ RnEnv}
691 %=====================
694 getLocalNameEnv :: RnMS LocalRdrEnv
695 getLocalNameEnv rn_down (SDown {rn_lenv = local_env})
698 getGlobalNameEnv :: RnMS GlobalRdrEnv
699 getGlobalNameEnv rn_down (SDown {rn_genv = global_env})
702 getGlobalAvails :: RnMS AvailEnv
703 getGlobalAvails rn_down (SDown {rn_avails = avails})
706 setLocalNameEnv :: LocalRdrEnv -> RnMS a -> RnMS a
707 setLocalNameEnv local_env' m rn_down l_down
708 = m rn_down (l_down {rn_lenv = local_env'})
710 getFixityEnv :: RnMS LocalFixityEnv
711 getFixityEnv rn_down (SDown {rn_fixenv = fixity_env})
714 extendFixityEnv :: [(Name, RenamedFixitySig)] -> RnMS a -> RnMS a
715 extendFixityEnv fixes enclosed_scope
716 rn_down l_down@(SDown {rn_fixenv = fixity_env})
718 new_fixity_env = extendNameEnvList fixity_env fixes
720 enclosed_scope rn_down (l_down {rn_fixenv = new_fixity_env})
724 \subsubsection{ Mode}
725 %=====================
728 getModeRn :: RnMS RnMode
729 getModeRn rn_down (SDown {rn_mode = mode})
732 setModeRn :: RnMode -> RnMS a -> RnMS a
733 setModeRn new_mode thing_inside rn_down l_down
734 = thing_inside rn_down (l_down {rn_mode = new_mode})
738 %************************************************************************
740 \subsection{Plumbing for rename-globals part}
742 %************************************************************************
745 getIfacesRn :: RnM d Ifaces
746 getIfacesRn (RnDown {rn_ifaces = iface_var}) _
747 = readIORef iface_var
749 setIfacesRn :: Ifaces -> RnM d ()
750 setIfacesRn ifaces (RnDown {rn_ifaces = iface_var}) _
751 = writeIORef iface_var ifaces