2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[TcIfaceSig]{Type checking of type signatures in interface files}
8 tcImportDecl, typecheckIface,
9 loadImportedInsts, loadImportedRules,
12 #include "HsVersions.h"
15 import LoadIface ( loadHomeInterface, predInstGates )
16 import IfaceEnv ( lookupIfaceTop, newGlobalBinder, lookupOrig,
17 extendIfaceIdEnv, extendIfaceTyVarEnv, newIPName,
18 tcIfaceTyVar, tcIfaceTyCon, tcIfaceClass, tcIfaceExtId,
19 tcIfaceDataCon, tcIfaceLclId,
20 newIfaceName, newIfaceNames )
21 import BuildTyCl ( buildSynTyCon, buildAlgTyCon, buildDataCon, buildClass )
23 import Type ( liftedTypeKind, splitTyConApp,
24 mkTyVarTys, mkGenTyConApp, mkTyVarTys, ThetaType, pprClassPred )
25 import TypeRep ( Type(..), PredType(..) )
26 import TyCon ( TyCon, tyConName )
27 import HscTypes ( ExternalPackageState(..), PackageInstEnv, PackageRuleBase,
28 HscEnv, TyThing(..), implicitTyThings, typeEnvIds,
29 ModIface(..), ModDetails(..), InstPool, ModGuts,
30 TypeEnv, mkTypeEnv, extendTypeEnvList, lookupTypeEnv,
32 import InstEnv ( extendInstEnv )
34 import PprCore ( pprIdRules )
35 import Rules ( extendRuleBaseList )
36 import CoreUtils ( exprType )
38 import CoreLint ( lintUnfolding )
39 import WorkWrap ( mkWrapper )
40 import InstEnv ( DFunId )
41 import Id ( Id, mkVanillaGlobal, mkLocalId )
42 import MkId ( mkFCallId )
43 import IdInfo ( IdInfo, CafInfo(..), WorkerInfo(..),
44 setUnfoldingInfoLazily, setAllStrictnessInfo, setWorkerInfo,
45 setArityInfo, setInlinePragInfo, setCafInfo,
46 vanillaIdInfo, newStrictnessInfo )
47 import Class ( Class )
48 import TyCon ( DataConDetails(..), tyConDataCons, tyConTyVars, isTupleTyCon, mkForeignTyCon )
49 import DataCon ( dataConWorkId, dataConExistentialTyVars, dataConArgTys )
50 import TysWiredIn ( tupleCon )
51 import Var ( TyVar, mkTyVar, tyVarKind )
52 import Name ( Name, NamedThing(..), nameModuleName, nameModule, nameOccName,
53 isWiredInName, wiredInNameTyThing_maybe, nameParent, nameParent_maybe )
55 import OccName ( OccName )
56 import Module ( Module, ModuleName, moduleName )
57 import UniqSupply ( initUs_ )
59 import SrcLoc ( noSrcLoc )
60 import Util ( zipWithEqual, dropList, equalLength, zipLazy )
61 import Maybes ( expectJust )
62 import CmdLineOpts ( DynFlag(..), dopt )
71 An IfaceDecl is populated with RdrNames, and these are not renamed to
72 Names before typechecking, because there should be no scope errors etc.
74 -- For (b) consider: f = $(...h....)
75 -- where h is imported, and calls f via an hi-boot file.
76 -- This is bad! But it is not seen as a staging error, because h
77 -- is indeed imported. We don't want the type-checker to black-hole
78 -- when simplifying and compiling the splice!
80 -- Simple solution: discard any unfolding that mentions a variable
81 -- bound in this module (and hence not yet processed).
82 -- The discarding happens when forkM finds a type error.
84 %************************************************************************
86 %* tcImportDecl is the key function for "faulting in" *
89 %************************************************************************
91 The main idea is this. We are chugging along type-checking source code, and
92 find a reference to GHC.Base.map. We call tcLookupGlobal, which doesn't find
93 it in the EPS type envt. So it
95 2 gets the decl for GHC.Base.map
96 3 typechecks it via tcIfaceDecl
97 4 and adds it to the type env in the EPS
99 Note that DURING STEP 4, we may find that map's type mentions a type
100 constructor that also
102 Notice that for imported things we read the current version from the EPS
103 mutable variable. This is important in situations like
105 where the code that e1 expands to might import some defns that
106 also turn out to be needed by the code that e2 expands to.
109 tcImportDecl :: Name -> IfG TyThing
110 -- Get the TyThing for this Name from an interface file
113 -- Make sure the interface is loaded
114 ; let { nd_doc = ptext SLIT("Need decl for") <+> ppr name }
115 ; traceIf (nd_doc <+> char '{') -- Brace matches the later message
116 ; loadHomeInterface nd_doc name
118 -- Get the real name of the thing, with a correct nameParent field.
119 -- Before the interface is loaded, we may have a non-committal 'Nothing'
120 -- in the namePareent field (made up by IfaceEnv.lookupOrig), but
121 -- loading the interface updates the name cache.
122 -- We need the right nameParent field in getThing
123 ; real_name <- lookupOrig (nameModuleName name) (nameOccName name)
125 -- Get the decl out of the EPS
126 ; main_thing <- ASSERT( real_name == name ) -- Unique should not change!
129 -- Record the import in the type env,
130 -- slurp any rules it allows in
131 ; recordImportOf main_thing
133 ; let { extra | getName main_thing == real_name = empty
134 | otherwise = brackets (ptext SLIT("when seeking") <+> ppr real_name) }
135 ; traceIf (ptext SLIT(" ...imported decl for") <+> ppr main_thing <+> extra <+> char '}')
138 -- Look up the wanted Name in the type envt; it might be
139 -- one of the subordinate members of the input thing
140 ; if real_name == getName main_thing
141 then return main_thing
144 ; return (expectJust "tcImportDecl" $
145 lookupTypeEnv (eps_PTE eps) real_name) }}
147 recordImportOf :: TyThing -> IfG ()
148 -- Update the EPS to record the import of the Thing
149 -- (a) augment the type environment; this is done even for wired-in
150 -- things, so that we don't go through this rigmarole a second time
151 -- (b) slurp in any rules to maintain the invariant that any rule
152 -- whose gates are all in the type envt, is in eps_rule_base
155 = do { new_things <- updateEps (\ eps ->
156 let { new_things = thing : implicitTyThings thing
157 ; new_type_env = extendTypeEnvList (eps_PTE eps) new_things
158 -- NB: opportunity for a very subtle loop here!
159 -- If working out what the implicitTyThings are involves poking
160 -- any of the fork'd thunks in 'thing', then here's what happens
161 -- * recordImportOf succeed, extending type-env with a thunk
162 -- * the next guy to pull on type-env forces the thunk
163 -- * which pokes the suspended forks
164 -- * which, to execute, need to consult type-env (to check
165 -- entirely unrelated types, perhaps)
167 in (eps { eps_PTE = new_type_env }, new_things)
169 ; traceIf (text "tcImport: extend type env" <+> ppr new_things)
172 getThing :: Name -> IfG TyThing
173 -- Find and typecheck the thing; the Name might be a "subordinate name"
174 -- of the "main thing" (e.g. the constructor of a data type declaration)
175 -- The Thing we return is the parent "main thing"
178 | Just thing <- wiredInNameTyThing_maybe name
181 | otherwise = do -- The normal case, not wired in
182 { -- Get the decl from the pool
183 mb_decl <- updateEps (\ eps -> selectDecl eps name)
186 Just decl -> initIfaceLcl (nameModuleName name) (tcIfaceDecl decl)
188 -- Side-effects EPS by faulting in any needed decls
189 -- (via nested calls to tcImportDecl)
192 Nothing -> do { ioToIOEnv (printErrs (msg defaultErrStyle)); failM }
193 -- Declaration not found
194 -- No errors-var to accumulate errors in, so just
195 -- print out the error right now
199 msg = hang (ptext SLIT("Can't find interface-file declaration for") <+> ppr (nameParent name))
200 2 (vcat [ptext SLIT("Probable cause: bug in .hi-boot file, or inconsistent .hi file"),
201 ptext SLIT("Use -ddump-if-trace to get an idea of which file caused the error")])
203 selectDecl :: ExternalPackageState -> Name -> (ExternalPackageState, Maybe IfaceDecl)
204 -- Use nameParent to get the parent name of the thing
205 selectDecl eps@(EPS { eps_decls = Pool decls_map n_in n_out}) name
206 = case lookupNameEnv decls_map name of {
207 -- This first lookup will usually fail for subordinate names, because
208 -- the relevant decl is the parent decl.
209 -- But, if we export a data type decl abstractly, its selectors
210 -- get separate type signatures in the interface file
212 decls' = delFromNameEnv decls_map name
214 (eps {eps_decls = Pool decls' n_in (n_out+1)}, Just decl) ;
217 case nameParent_maybe name of {
218 Nothing -> (eps, Nothing ) ; -- No "parent"
219 Just main_name -> -- Has a parent; try that
221 case lookupNameEnv decls_map main_name of {
223 decls' = delFromNameEnv decls_map main_name
225 (eps {eps_decls = Pool decls' n_in (n_out+1)}, Just decl) ;
226 Nothing -> (eps, Nothing)
230 %************************************************************************
232 Type-checking a complete interface
234 %************************************************************************
236 Suppose we discover we don't need to recompile. Then we must type
237 check the old interface file. This is a bit different to the
238 incremental type checking we do as we suck in interface files. Instead
239 we do things similarly as when we are typechecking source decls: we
240 bring into scope the type envt for the interface all at once, using a
241 knot. Remember, the decls aren't necessarily in dependency order --
242 and even if they were, the type decls might be mutually recursive.
245 typecheckIface :: HscEnv
246 -> ModIface -- Get the decls from here
248 typecheckIface hsc_env iface@(ModIface { mi_module = mod, mi_decls = ver_decls,
249 mi_rules = rules, mi_insts = dfuns })
250 = initIfaceTc hsc_env iface $ \ tc_env_var -> do
251 { -- Typecheck the decls
252 names <- mappM (lookupOrig (moduleName mod) . ifName) decls
253 ; ty_things <- fixM (\ rec_ty_things -> do
254 { writeMutVar tc_env_var (mkNameEnv (names `zipLazy` rec_ty_things))
255 -- This only makes available the "main" things,
256 -- but that's enough for the strictly-checked part
257 ; mapM tcIfaceDecl decls })
259 -- Now augment the type envt with all the implicit things
260 -- These will be needed when type-checking the unfoldings for
261 -- the IfaceIds, but this is done lazily, so writing the thing
263 ; let { add_implicits main_thing = main_thing : implicitTyThings main_thing
264 ; type_env = mkTypeEnv (concatMap add_implicits ty_things) }
265 ; writeMutVar tc_env_var type_env
267 -- Now do those rules and instances
268 ; dfuns <- mapM tcIfaceInst (mi_insts iface)
269 ; rules <- mapM tcIfaceRule (mi_rules iface)
272 ; return (ModDetails { md_types = type_env, md_insts = dfuns, md_rules = rules })
275 decls = map snd ver_decls
279 %************************************************************************
281 Type and class declarations
283 %************************************************************************
285 When typechecking a data type decl, we *lazily* (via forkM) typecheck
286 the constructor argument types. This is in the hope that we may never
287 poke on those argument types, and hence may never need to load the
288 interface files for types mentioned in the arg types.
291 data Foo.S = MkS Baz.T
292 Mabye we can get away without even loading the interface for Baz!
294 This is not just a performance thing. Suppose we have
295 data Foo.S = MkS Baz.T
296 data Baz.T = MkT Foo.S
297 (in different interface files, of course).
298 Now, first we load and typecheck Foo.S, and add it to the type envt.
299 If we do explore MkS's argument, we'll load and typecheck Baz.T.
300 If we explore MkT's argument we'll find Foo.S already in the envt.
302 If we typechecked constructor args eagerly, when loading Foo.S we'd try to
303 typecheck the type Baz.T. So we'd fault in Baz.T... and then need Foo.S...
304 which isn't done yet.
306 All very cunning. However, there is a rather subtle gotcha which bit
307 me when developing this stuff. When we typecheck the decl for S, we
308 extend the type envt with S, MkS, and all its implicit Ids. Suppose
309 (a bug, but it happened) that the list of implicit Ids depended in
310 turn on the constructor arg types. Then the following sequence of
312 * we build a thunk <t> for the constructor arg tys
313 * we build a thunk for the extended type environment (depends on <t>)
314 * we write the extended type envt into the global EPS mutvar
316 Now we look something up in the type envt
318 * which reads the global type envt out of the global EPS mutvar
319 * but that depends in turn on <t>
321 It's subtle, because, it'd work fine if we typechecked the constructor args
322 eagerly -- they don't need the extended type envt. They just get the extended
323 type envt by accident, because they look at it later.
325 What this means is that the implicitTyThings MUST NOT DEPEND on any of
330 tcIfaceDecl :: IfaceDecl -> IfL TyThing
332 tcIfaceDecl (IfaceId {ifName = occ_name, ifType = iface_type, ifIdInfo = info})
333 = do { name <- lookupIfaceTop occ_name
334 ; ty <- tcIfaceType iface_type
335 ; info <- tcIdInfo name ty info
336 ; return (AnId (mkVanillaGlobal name ty info)) }
338 tcIfaceDecl (IfaceData {ifND = new_or_data, ifName = occ_name,
339 ifTyVars = tv_bndrs, ifCtxt = rdr_ctxt,
341 ifVrcs = arg_vrcs, ifRec = is_rec,
342 ifGeneric = want_generic })
343 = do { tc_name <- lookupIfaceTop occ_name
344 ; bindIfaceTyVars tv_bndrs $ \ tyvars -> do
346 { traceIf (text "tcIfaceDecl" <+> ppr rdr_ctxt)
348 ; ctxt <- forkM (ptext SLIT("Ctxt of data decl") <+> ppr tc_name) $
350 -- The reason for laziness here is to postpone
351 -- looking at the context, because the class may not
352 -- be in the type envt yet. E.g.
353 -- class Real a where { toRat :: a -> Ratio Integer }
354 -- data (Real a) => Ratio a = ...
355 -- We suck in the decl for Real, and type check it, which sucks
356 -- in the data type Ratio; but we must postpone typechecking the
359 ; tycon <- fixM ( \ tycon -> do
360 { cons <- tcIfaceDataCons tycon tyvars ctxt rdr_cons
361 ; tycon <- buildAlgTyCon new_or_data tc_name tyvars ctxt cons
362 arg_vrcs is_rec want_generic
365 ; traceIf (text "tcIfaceDecl4" <+> ppr tycon)
366 ; return (ATyCon tycon)
369 tcIfaceDecl (IfaceSyn {ifName = occ_name, ifTyVars = tv_bndrs,
370 ifSynRhs = rdr_rhs_ty, ifVrcs = arg_vrcs})
371 = bindIfaceTyVars tv_bndrs $ \ tyvars -> do
372 { tc_name <- lookupIfaceTop occ_name
373 ; rhs_ty <- tcIfaceType rdr_rhs_ty
374 ; return (ATyCon (buildSynTyCon tc_name tyvars rhs_ty arg_vrcs))
377 tcIfaceDecl (IfaceClass {ifCtxt = rdr_ctxt, ifName = occ_name, ifTyVars = tv_bndrs,
378 ifFDs = rdr_fds, ifSigs = rdr_sigs,
379 ifVrcs = tc_vrcs, ifRec = tc_isrec })
380 = bindIfaceTyVars tv_bndrs $ \ tyvars -> do
381 { cls_name <- lookupIfaceTop occ_name
382 ; ctxt <- tcIfaceCtxt rdr_ctxt
383 ; sigs <- mappM tc_sig rdr_sigs
384 ; fds <- mappM tc_fd rdr_fds
385 ; cls <- buildClass cls_name tyvars ctxt fds sigs tc_isrec tc_vrcs
386 ; return (AClass cls) }
388 tc_sig (IfaceClassOp occ dm rdr_ty)
389 = do { op_name <- lookupIfaceTop occ
390 ; op_ty <- forkM (mk_doc op_name rdr_ty) (tcIfaceType rdr_ty)
391 -- Must be done lazily for just the same reason as the
392 -- context of a data decl: the type sig might mention the
393 -- class being defined
394 ; return (op_name, dm, op_ty) }
396 mk_doc op_name op_ty = ptext SLIT("Class op") <+> sep [ppr op_name, ppr op_ty]
398 tc_fd (tvs1, tvs2) = do { tvs1' <- mappM tcIfaceTyVar tvs1
399 ; tvs2' <- mappM tcIfaceTyVar tvs2
400 ; return (tvs1', tvs2') }
402 tcIfaceDecl (IfaceForeign {ifName = rdr_name, ifExtName = ext_name})
403 = do { name <- lookupIfaceTop rdr_name
404 ; return (ATyCon (mkForeignTyCon name ext_name
405 liftedTypeKind 0 [])) }
407 tcIfaceDataCons tycon tyvars ctxt Unknown
410 tcIfaceDataCons tycon tyvars ctxt (DataCons cs)
411 = mappM tc_con_decl cs `thenM` \ data_cons ->
412 returnM (DataCons data_cons)
414 tc_con_decl (IfaceConDecl occ ex_tvs ex_ctxt args stricts field_lbls)
415 = bindIfaceTyVars ex_tvs $ \ ex_tyvars -> do
416 { name <- lookupIfaceTop occ
417 ; ex_theta <- tcIfaceCtxt ex_ctxt -- Laziness seems not worth the bother here
419 -- Read the argument types, but lazily to avoid faulting in
420 -- the component types unless they are really needed
421 ; arg_tys <- forkM (mk_doc name args) (mappM tcIfaceType args) ;
423 ; lbl_names <- mappM lookupIfaceTop field_lbls
425 ; buildDataCon name stricts lbl_names
426 tyvars ctxt ex_tyvars ex_theta
429 mk_doc con_name args = ptext SLIT("Constructor") <+> sep [ppr con_name, ppr args]
433 %************************************************************************
437 %************************************************************************
439 The gating story for instance declarations
440 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
441 When we are looking for a dict (C t1..tn), we slurp in instance decls for
443 mention at least one of the type constructors
444 at the roots of t1..tn
446 Why "at least one" rather than "all"? Because functional dependencies
447 complicate the picture. Consider
448 class C a b | a->b where ...
449 instance C Foo Baz where ...
450 Here, the gates are really only C and Foo, *not* Baz.
451 That is, if C and Foo are visible, even if Baz isn't, we must
452 slurp the decl, even if Baz is thus far completely unknown to the
455 Why "roots of the types"? Reason is overlap. For example, suppose there
456 are interfaces in the pool for
460 Then, if we are trying to resolve (C Int x), we need (a)
461 if we are trying to resolve (C x [y]), we need *both* (b) and (c),
462 even though T is not involved yet, so that we spot the overlap.
465 NOTE: if you use an instance decl with NO type constructors
466 instance C a where ...
467 and look up an Inst that only has type variables such as (C (n o))
468 then GHC won't necessarily suck in the instances that overlap with this.
472 loadImportedInsts :: Class -> [Type] -> TcM PackageInstEnv
473 loadImportedInsts cls tys
474 = do { -- Get interfaces for wired-in things, such as Integer
475 -- Any non-wired-in tycons will already be loaded, else
476 -- we couldn't have them in the Type
477 ; this_mod <- getModule
478 ; let { (cls_gate, tc_gates) = predInstGates cls tys
479 ; imp_wi n = isWiredInName n && this_mod /= nameModule n
480 ; wired_tcs = filter imp_wi tc_gates }
481 -- Wired-in tycons not from this module. The "this-module"
482 -- test bites only when compiling Base etc, because loadHomeInterface
483 -- barfs if it's asked to load a non-existent interface
484 ; if null wired_tcs then returnM ()
485 else initIfaceTcRn (mapM_ (loadHomeInterface wired_doc) wired_tcs)
487 ; eps_var <- getEpsVar
488 ; eps <- readMutVar eps_var
490 -- For interest: report the no-type-constructor case.
491 -- Don't report when -fallow-undecidable-instances is on, because then
492 -- we call loadImportedInsts when looking up even predicates like (C a)
493 -- But without undecidable instances it's rare to see C (a b) and
494 -- somethat interesting
497 ; WARN( not (dopt Opt_AllowUndecidableInstances dflags) && null tc_gates,
498 ptext SLIT("Interesting! No tycons in Inst:")
499 <+> pprClassPred cls tys )
503 -- Suck in the instances
504 ; let { (inst_pool', iface_insts)
505 = selectInsts (eps_insts eps) cls_gate tc_gates }
507 -- Empty => finish up rapidly, without writing to eps
508 ; if null iface_insts then
509 return (eps_inst_env eps)
511 { writeMutVar eps_var (eps {eps_insts = inst_pool'})
513 ; traceIf (sep [ptext SLIT("Importing instances for") <+> pprClassPred cls tys,
514 nest 2 (vcat (map ppr iface_insts))])
516 -- Typecheck the new instances
517 ; dfuns <- initIfaceTcRn (mappM tc_inst iface_insts)
519 -- And put them in the package instance environment
520 ; updateEps ( \ eps ->
522 inst_env' = foldl extendInstEnv (eps_inst_env eps) dfuns
524 (eps { eps_inst_env = inst_env' }, inst_env')
527 wired_doc = ptext SLIT("Need home inteface for wired-in thing")
529 tc_inst (mod, inst) = initIfaceLcl mod (tcIfaceInst inst)
531 tcIfaceInst :: IfaceInst -> IfL DFunId
532 tcIfaceInst (IfaceInst { ifDFun = dfun_occ })
533 = tcIfaceExtId (LocalTop dfun_occ)
535 selectInsts :: InstPool -> Name -> [Name] -> (InstPool, [(ModuleName, IfaceInst)])
536 selectInsts pool@(Pool insts n_in n_out) cls tycons
537 = (Pool insts' n_in (n_out + length iface_insts), iface_insts)
539 (insts', iface_insts)
540 = case lookupNameEnv insts cls of {
541 Nothing -> (insts, []) ;
544 case choose1 gated_insts of {
545 (_, []) -> (insts, []) ; -- None picked
546 (gated_insts', iface_insts') ->
548 (extendNameEnv insts cls gated_insts', iface_insts') }}
551 | null tycons -- Bizarre special case of C (a b); then there are no tycons
552 = ([], map snd gated_insts) -- Just grab all the instances, no real alternative
553 | otherwise -- Normal case
554 = foldl choose2 ([],[]) gated_insts
556 -- Reverses the gated decls, but that doesn't matter
557 choose2 (gis, decls) (gates, decl)
558 | null gates -- Happens when we have 'instance T a where ...'
559 || any (`elem` tycons) gates = (gis, decl:decls)
560 | otherwise = ((gates,decl) : gis, decls)
563 %************************************************************************
567 %************************************************************************
569 We move a IfaceRule from eps_rules to eps_rule_base when all its LHS free vars
570 are in the type environment. However, remember that typechecking a Rule may
571 (as a side effect) augment the type envt, and so we may need to iterate the process.
574 loadImportedRules :: HscEnv -> ModGuts -> IO PackageRuleBase
575 loadImportedRules hsc_env guts
576 = initIfaceRules hsc_env guts $ do
578 if_rules <- updateEps (\ eps ->
579 let { (new_pool, if_rules) = selectRules (eps_rules eps) (eps_PTE eps) }
580 in (eps { eps_rules = new_pool }, if_rules) )
582 ; traceIf (ptext SLIT("Importing rules:") <+> vcat (map ppr if_rules))
584 ; let tc_rule (mod, rule) = initIfaceLcl mod (tcIfaceRule rule)
585 ; core_rules <- mapM tc_rule if_rules
588 ; traceIf (ptext SLIT("Imported rules:") <+> pprIdRules core_rules)
590 -- Update the rule base and return it
591 ; updateEps (\ eps ->
592 let { new_rule_base = extendRuleBaseList (eps_rule_base eps) core_rules }
593 in (eps { eps_rule_base = new_rule_base }, new_rule_base)
596 -- Strictly speaking, at this point we should go round again, since
597 -- typechecking one set of rules may bring in new things which enable
598 -- some more rules to come in. But we call loadImportedRules several
599 -- times anyway, so I'm going to be lazy and ignore this.
603 selectRules :: RulePool -> TypeEnv -> (RulePool, [(ModuleName, IfaceRule)])
604 -- Not terribly efficient. Look at each rule in the pool to see if
605 -- all its gates are in the type env. If so, take it out of the pool.
606 -- If not, trim its gates for next time.
607 selectRules (Pool rules n_in n_out) type_env
608 = (Pool rules' n_in (n_out + length if_rules), if_rules)
610 (rules', if_rules) = foldl do_one ([], []) rules
612 do_one (pool, if_rules) (gates, rule)
613 | null gates' = (pool, rule:if_rules)
614 | otherwise = ((gates',rule) : pool, if_rules)
616 gates' = filter (not . (`elemNameEnv` type_env)) gates
619 tcIfaceRule :: IfaceRule -> IfL IdCoreRule
620 tcIfaceRule (IfaceRule {ifRuleName = rule_name, ifActivation = act, ifRuleBndrs = bndrs,
621 ifRuleHead = fn_rdr, ifRuleArgs = args, ifRuleRhs = rhs })
622 = bindIfaceBndrs bndrs $ \ bndrs' ->
623 do { fn <- tcIfaceExtId fn_rdr
624 ; args' <- mappM tcIfaceExpr args
625 ; rhs' <- tcIfaceExpr rhs
626 ; returnM (fn, (Rule rule_name act bndrs' args' rhs')) }
628 tcIfaceRule (IfaceBuiltinRule fn_rdr core_rule)
629 = do { fn <- tcIfaceExtId fn_rdr
630 ; returnM (fn, core_rule) }
634 %************************************************************************
638 %************************************************************************
641 tcIfaceType :: IfaceType -> IfL Type
642 tcIfaceType (IfaceTyVar n) = do { tv <- tcIfaceTyVar n; return (TyVarTy tv) }
643 tcIfaceType (IfaceAppTy t1 t2) = do { t1' <- tcIfaceType t1; t2' <- tcIfaceType t2; return (AppTy t1' t2') }
644 tcIfaceType (IfaceFunTy t1 t2) = do { t1' <- tcIfaceType t1; t2' <- tcIfaceType t2; return (FunTy t1' t2') }
645 tcIfaceType (IfaceTyConApp tc ts) = do { tc' <- tcIfaceTyCon tc; ts' <- tcIfaceTypes ts; return (mkGenTyConApp tc' ts') }
646 tcIfaceType (IfaceForAllTy tv t) = bindIfaceTyVar tv $ \ tv' -> do { t' <- tcIfaceType t; return (ForAllTy tv' t') }
647 tcIfaceType (IfacePredTy st) = do { st' <- tcIfacePredType st; return (PredTy st') }
649 tcIfaceTypes tys = mapM tcIfaceType tys
651 -----------------------------------------
652 tcIfacePredType :: IfacePredType -> IfL PredType
653 tcIfacePredType (IfaceClassP cls ts) = do { cls' <- tcIfaceClass cls; ts' <- tcIfaceTypes ts; return (ClassP cls' ts') }
654 tcIfacePredType (IfaceIParam ip t) = do { ip' <- newIPName ip; t' <- tcIfaceType t; return (IParam ip' t') }
656 -----------------------------------------
657 tcIfaceCtxt :: IfaceContext -> IfL ThetaType
658 tcIfaceCtxt sts = mappM tcIfacePredType sts
662 %************************************************************************
666 %************************************************************************
669 tcIfaceExpr :: IfaceExpr -> IfL CoreExpr
670 tcIfaceExpr (IfaceType ty)
671 = tcIfaceType ty `thenM` \ ty' ->
674 tcIfaceExpr (IfaceLcl name)
675 = tcIfaceLclId name `thenM` \ id ->
678 tcIfaceExpr (IfaceExt gbl)
679 = tcIfaceExtId gbl `thenM` \ id ->
682 tcIfaceExpr (IfaceLit lit)
685 tcIfaceExpr (IfaceFCall cc ty)
686 = tcIfaceType ty `thenM` \ ty' ->
687 newUnique `thenM` \ u ->
688 returnM (Var (mkFCallId u cc ty'))
690 tcIfaceExpr (IfaceTuple boxity args)
691 = mappM tcIfaceExpr args `thenM` \ args' ->
693 -- Put the missing type arguments back in
694 con_args = map (Type . exprType) args' ++ args'
696 returnM (mkApps (Var con_id) con_args)
699 con_id = dataConWorkId (tupleCon boxity arity)
702 tcIfaceExpr (IfaceLam bndr body)
703 = bindIfaceBndr bndr $ \ bndr' ->
704 tcIfaceExpr body `thenM` \ body' ->
705 returnM (Lam bndr' body')
707 tcIfaceExpr (IfaceApp fun arg)
708 = tcIfaceExpr fun `thenM` \ fun' ->
709 tcIfaceExpr arg `thenM` \ arg' ->
710 returnM (App fun' arg')
712 tcIfaceExpr (IfaceCase scrut case_bndr alts)
713 = tcIfaceExpr scrut `thenM` \ scrut' ->
714 newIfaceName case_bndr `thenM` \ case_bndr_name ->
716 scrut_ty = exprType scrut'
717 case_bndr' = mkLocalId case_bndr_name scrut_ty
718 tc_app = splitTyConApp scrut_ty
719 -- NB: Won't always succeed (polymoprhic case)
720 -- but won't be demanded in those cases
721 -- NB: not tcSplitTyConApp; we are looking at Core here
722 -- look through non-rec newtypes to find the tycon that
723 -- corresponds to the datacon in this case alternative
725 extendIfaceIdEnv [case_bndr'] $
726 mappM (tcIfaceAlt tc_app) alts `thenM` \ alts' ->
727 returnM (Case scrut' case_bndr' alts')
729 tcIfaceExpr (IfaceLet (IfaceNonRec bndr rhs) body)
730 = tcIfaceExpr rhs `thenM` \ rhs' ->
731 bindIfaceId bndr $ \ bndr' ->
732 tcIfaceExpr body `thenM` \ body' ->
733 returnM (Let (NonRec bndr' rhs') body')
735 tcIfaceExpr (IfaceLet (IfaceRec pairs) body)
736 = bindIfaceIds bndrs $ \ bndrs' ->
737 mappM tcIfaceExpr rhss `thenM` \ rhss' ->
738 tcIfaceExpr body `thenM` \ body' ->
739 returnM (Let (Rec (bndrs' `zip` rhss')) body')
741 (bndrs, rhss) = unzip pairs
743 tcIfaceExpr (IfaceNote note expr)
744 = tcIfaceExpr expr `thenM` \ expr' ->
746 IfaceCoerce to_ty -> tcIfaceType to_ty `thenM` \ to_ty' ->
747 returnM (Note (Coerce to_ty'
748 (exprType expr')) expr')
749 IfaceInlineCall -> returnM (Note InlineCall expr')
750 IfaceInlineMe -> returnM (Note InlineMe expr')
751 IfaceSCC cc -> returnM (Note (SCC cc) expr')
752 IfaceCoreNote n -> returnM (Note (CoreNote n) expr')
754 -------------------------
755 tcIfaceAlt _ (IfaceDefault, names, rhs)
756 = ASSERT( null names )
757 tcIfaceExpr rhs `thenM` \ rhs' ->
758 returnM (DEFAULT, [], rhs')
760 tcIfaceAlt _ (IfaceLitAlt lit, names, rhs)
761 = ASSERT( null names )
762 tcIfaceExpr rhs `thenM` \ rhs' ->
763 returnM (LitAlt lit, [], rhs')
765 -- A case alternative is made quite a bit more complicated
766 -- by the fact that we omit type annotations because we can
767 -- work them out. True enough, but its not that easy!
768 tcIfaceAlt (tycon, inst_tys) (IfaceDataAlt data_occ, arg_occs, rhs)
770 tycon_mod = nameModuleName (tyConName tycon)
772 tcIfaceDataCon (ExtPkg tycon_mod data_occ) `thenM` \ con ->
773 newIfaceNames arg_occs `thenM` \ arg_names ->
775 ex_tyvars = dataConExistentialTyVars con
776 main_tyvars = tyConTyVars tycon
777 ex_tyvars' = [mkTyVar name (tyVarKind tv) | (name,tv) <- arg_names `zip` ex_tyvars]
778 ex_tys' = mkTyVarTys ex_tyvars'
779 arg_tys = dataConArgTys con (inst_tys ++ ex_tys')
780 id_names = dropList ex_tyvars arg_names
783 | not (equalLength id_names arg_tys)
784 = pprPanic "tcIfaceAlts" (ppr (con, arg_names, rhs) $$
785 (ppr main_tyvars <+> ppr ex_tyvars) $$
789 = zipWithEqual "tcIfaceAlts" mkLocalId id_names arg_tys
791 ASSERT2( con `elem` tyConDataCons tycon && equalLength inst_tys main_tyvars,
792 ppr con $$ ppr tycon $$ ppr (tyConDataCons tycon) $$ ppr arg_tys $$ ppr main_tyvars )
793 extendIfaceTyVarEnv ex_tyvars' $
794 extendIfaceIdEnv arg_ids $
795 tcIfaceExpr rhs `thenM` \ rhs' ->
796 returnM (DataAlt con, ex_tyvars' ++ arg_ids, rhs')
798 tcIfaceAlt (tycon, inst_tys) (IfaceTupleAlt boxity, arg_occs, rhs)
799 = newIfaceNames arg_occs `thenM` \ arg_names ->
801 [con] = tyConDataCons tycon
802 arg_ids = zipWithEqual "tcIfaceAlts" mkLocalId arg_names inst_tys
804 ASSERT( isTupleTyCon tycon )
805 extendIfaceIdEnv arg_ids $
806 tcIfaceExpr rhs `thenM` \ rhs' ->
807 returnM (DataAlt con, arg_ids, rhs')
812 tcExtCoreBindings :: Module -> [IfaceBinding] -> IfL [CoreBind] -- Used for external core
813 tcExtCoreBindings mod [] = return []
814 tcExtCoreBindings mod (b:bs) = do_one mod b (tcExtCoreBindings mod bs)
816 do_one :: Module -> IfaceBinding -> IfL [CoreBind] -> IfL [CoreBind]
817 do_one mod (IfaceNonRec bndr rhs) thing_inside
818 = do { rhs' <- tcIfaceExpr rhs
819 ; bndr' <- newExtCoreBndr mod bndr
820 ; extendIfaceIdEnv [bndr'] $ do
821 { core_binds <- thing_inside
822 ; return (NonRec bndr' rhs' : core_binds) }}
824 do_one mod (IfaceRec pairs) thing_inside
825 = do { bndrs' <- mappM (newExtCoreBndr mod) bndrs
826 ; extendIfaceIdEnv bndrs' $ do
827 { rhss' <- mappM tcIfaceExpr rhss
828 ; core_binds <- thing_inside
829 ; return (Rec (bndrs' `zip` rhss') : core_binds) }}
831 (bndrs,rhss) = unzip pairs
835 %************************************************************************
839 %************************************************************************
842 tcIdInfo name ty NoInfo = return vanillaIdInfo
843 tcIdInfo name ty DiscardedInfo = return vanillaIdInfo
844 tcIdInfo name ty (HasInfo iface_info)
845 = foldlM tcPrag init_info iface_info
847 -- Set the CgInfo to something sensible but uninformative before
848 -- we start; default assumption is that it has CAFs
849 init_info = vanillaIdInfo
851 tcPrag info HsNoCafRefs = returnM (info `setCafInfo` NoCafRefs)
852 tcPrag info (HsArity arity) = returnM (info `setArityInfo` arity)
853 tcPrag info (HsStrictness str) = returnM (info `setAllStrictnessInfo` Just str)
855 -- The next two are lazy, so they don't transitively suck stuff in
856 tcPrag info (HsWorker nm arity) = tcWorkerInfo ty info nm arity
857 tcPrag info (HsUnfold inline_prag expr)
858 = tcPragExpr name expr `thenM` \ maybe_expr' ->
860 -- maybe_expr' doesn't get looked at if the unfolding
861 -- is never inspected; so the typecheck doesn't even happen
862 unfold_info = case maybe_expr' of
863 Nothing -> noUnfolding
864 Just expr' -> mkTopUnfolding expr'
866 returnM (info `setUnfoldingInfoLazily` unfold_info
867 `setInlinePragInfo` inline_prag)
871 tcWorkerInfo ty info wkr_name arity
872 = do { mb_wkr_id <- forkM_maybe doc (tcIfaceExtId (LocalTop wkr_name))
874 -- We return without testing maybe_wkr_id, but as soon as info is
875 -- looked at we will test it. That's ok, because its outside the
876 -- knot; and there seems no big reason to further defer the
877 -- tcIfaceId lookup. (Contrast with tcPragExpr, where postponing walking
878 -- over the unfolding until it's actually used does seem worth while.)
879 ; us <- newUniqueSupply
881 ; returnM (case mb_wkr_id of
883 Just wkr_id -> add_wkr_info us wkr_id info) }
885 doc = text "Worker for" <+> ppr wkr_name
886 add_wkr_info us wkr_id info
887 = info `setUnfoldingInfoLazily` mk_unfolding us wkr_id
888 `setWorkerInfo` HasWorker wkr_id arity
890 mk_unfolding us wkr_id = mkTopUnfolding (initUs_ us (mkWrapper ty strict_sig) wkr_id)
892 -- We are relying here on strictness info always appearing
893 -- before worker info, fingers crossed ....
894 strict_sig = case newStrictnessInfo info of
896 Nothing -> pprPanic "Worker info but no strictness for" (ppr wkr_name)
899 For unfoldings we try to do the job lazily, so that we never type check
900 an unfolding that isn't going to be looked at.
903 tcPragExpr :: Name -> IfaceExpr -> IfL (Maybe CoreExpr)
906 tcIfaceExpr expr `thenM` \ core_expr' ->
908 -- Check for type consistency in the unfolding
909 ifOptM Opt_DoCoreLinting (
910 get_in_scope_ids `thenM` \ in_scope ->
911 case lintUnfolding noSrcLoc in_scope core_expr' of
912 Nothing -> returnM ()
913 Just fail_msg -> pprPanic "Iface Lint failure" (doc <+> fail_msg)
918 doc = text "Unfolding of" <+> ppr name
919 get_in_scope_ids -- Urgh; but just for linting
921 do { env <- getGblEnv
922 ; case if_rec_types env of {
923 Nothing -> return [] ;
924 Just (_, get_env) -> do
925 { type_env <- get_env
926 ; return (typeEnvIds type_env) }}}
931 %************************************************************************
935 %************************************************************************
938 bindIfaceBndr :: IfaceBndr -> (CoreBndr -> IfL a) -> IfL a
939 bindIfaceBndr (IfaceIdBndr bndr) thing_inside
940 = bindIfaceId bndr thing_inside
941 bindIfaceBndr (IfaceTvBndr bndr) thing_inside
942 = bindIfaceTyVar bndr thing_inside
944 bindIfaceBndrs :: [IfaceBndr] -> ([CoreBndr] -> IfL a) -> IfL a
945 bindIfaceBndrs [] thing_inside = thing_inside []
946 bindIfaceBndrs (b:bs) thing_inside
947 = bindIfaceBndr b $ \ b' ->
948 bindIfaceBndrs bs $ \ bs' ->
949 thing_inside (b':bs')
951 -----------------------
952 bindIfaceId :: (OccName, IfaceType) -> (Id -> IfL a) -> IfL a
953 bindIfaceId (occ, ty) thing_inside
954 = do { name <- newIfaceName occ
955 ; ty' <- tcIfaceType ty
956 ; let { id = mkLocalId name ty' }
957 ; extendIfaceIdEnv [id] (thing_inside id) }
959 bindIfaceIds :: [(OccName, IfaceType)] -> ([Id] -> IfL a) -> IfL a
960 bindIfaceIds bndrs thing_inside
961 = do { names <- newIfaceNames occs
962 ; tys' <- mappM tcIfaceType tys
963 ; let { ids = zipWithEqual "tcCoreValBndr" mkLocalId names tys' }
964 ; extendIfaceIdEnv ids (thing_inside ids) }
966 (occs,tys) = unzip bndrs
969 -----------------------
970 newExtCoreBndr :: Module -> (OccName, IfaceType) -> IfL Id
971 newExtCoreBndr mod (occ, ty)
972 = do { name <- newGlobalBinder mod occ Nothing noSrcLoc
973 ; ty' <- tcIfaceType ty
974 ; return (mkLocalId name ty') }
976 -----------------------
977 bindIfaceTyVar :: IfaceTvBndr -> (TyVar -> IfL a) -> IfL a
978 bindIfaceTyVar (occ,kind) thing_inside
979 = do { name <- newIfaceName occ
980 ; let tyvar = mk_iface_tyvar name kind
981 ; extendIfaceTyVarEnv [tyvar] (thing_inside tyvar) }
983 bindIfaceTyVars :: [IfaceTvBndr] -> ([TyVar] -> IfL a) -> IfL a
984 bindIfaceTyVars bndrs thing_inside
985 = do { names <- newIfaceNames occs
986 ; let tyvars = zipWith mk_iface_tyvar names kinds
987 ; extendIfaceTyVarEnv tyvars (thing_inside tyvars) }
989 (occs,kinds) = unzip bndrs
991 mk_iface_tyvar name kind = mkTyVar name kind