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(..) )
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 -- Suck in the instances
491 ; let { (inst_pool', iface_insts)
492 = WARN( null tc_gates, ptext SLIT("Interesting! No tycons in Inst:")
493 <+> pprClassPred cls tys )
494 selectInsts (eps_insts eps) cls_gate tc_gates }
496 -- Empty => finish up rapidly, without writing to eps
497 ; if null iface_insts then
498 return (eps_inst_env eps)
500 { writeMutVar eps_var (eps {eps_insts = inst_pool'})
502 ; traceIf (sep [ptext SLIT("Importing instances for") <+> pprClassPred cls tys,
503 nest 2 (vcat (map ppr iface_insts))])
505 -- Typecheck the new instances
506 ; dfuns <- initIfaceTcRn (mappM tc_inst iface_insts)
508 -- And put them in the package instance environment
509 ; updateEps ( \ eps ->
511 inst_env' = foldl extendInstEnv (eps_inst_env eps) dfuns
513 (eps { eps_inst_env = inst_env' }, inst_env')
516 wired_doc = ptext SLIT("Need home inteface for wired-in thing")
518 tc_inst (mod, inst) = initIfaceLcl mod (tcIfaceInst inst)
520 tcIfaceInst :: IfaceInst -> IfL DFunId
521 tcIfaceInst (IfaceInst { ifDFun = dfun_occ })
522 = tcIfaceExtId (LocalTop dfun_occ)
524 selectInsts :: InstPool -> Name -> [Name] -> (InstPool, [(ModuleName, IfaceInst)])
525 selectInsts pool@(Pool insts n_in n_out) cls tycons
526 = (Pool insts' n_in (n_out + length iface_insts), iface_insts)
528 (insts', iface_insts)
529 = case lookupNameEnv insts cls of {
530 Nothing -> (insts, []) ;
533 case choose1 gated_insts of {
534 (_, []) -> (insts, []) ; -- None picked
535 (gated_insts', iface_insts') ->
537 (extendNameEnv insts cls gated_insts', iface_insts') }}
540 | null tycons -- Bizarre special case of C (a b); then there are no tycons
541 = ([], map snd gated_insts) -- Just grab all the instances, no real alternative
542 | otherwise -- Normal case
543 = foldl choose2 ([],[]) gated_insts
545 -- Reverses the gated decls, but that doesn't matter
546 choose2 (gis, decls) (gates, decl)
547 | null gates -- Happens when we have 'instance T a where ...'
548 || any (`elem` tycons) gates = (gis, decl:decls)
549 | otherwise = ((gates,decl) : gis, decls)
552 %************************************************************************
556 %************************************************************************
558 We move a IfaceRule from eps_rules to eps_rule_base when all its LHS free vars
559 are in the type environment. However, remember that typechecking a Rule may
560 (as a side effect) augment the type envt, and so we may need to iterate the process.
563 loadImportedRules :: HscEnv -> ModGuts -> IO PackageRuleBase
564 loadImportedRules hsc_env guts
565 = initIfaceRules hsc_env guts $ do
567 if_rules <- updateEps (\ eps ->
568 let { (new_pool, if_rules) = selectRules (eps_rules eps) (eps_PTE eps) }
569 in (eps { eps_rules = new_pool }, if_rules) )
571 ; traceIf (ptext SLIT("Importing rules:") <+> vcat (map ppr if_rules))
573 ; let tc_rule (mod, rule) = initIfaceLcl mod (tcIfaceRule rule)
574 ; core_rules <- mapM tc_rule if_rules
577 ; traceIf (ptext SLIT("Imported rules:") <+> pprIdRules core_rules)
579 -- Update the rule base and return it
580 ; updateEps (\ eps ->
581 let { new_rule_base = extendRuleBaseList (eps_rule_base eps) core_rules }
582 in (eps { eps_rule_base = new_rule_base }, new_rule_base)
585 -- Strictly speaking, at this point we should go round again, since
586 -- typechecking one set of rules may bring in new things which enable
587 -- some more rules to come in. But we call loadImportedRules several
588 -- times anyway, so I'm going to be lazy and ignore this.
592 selectRules :: RulePool -> TypeEnv -> (RulePool, [(ModuleName, IfaceRule)])
593 -- Not terribly efficient. Look at each rule in the pool to see if
594 -- all its gates are in the type env. If so, take it out of the pool.
595 -- If not, trim its gates for next time.
596 selectRules (Pool rules n_in n_out) type_env
597 = (Pool rules' n_in (n_out + length if_rules), if_rules)
599 (rules', if_rules) = foldl do_one ([], []) rules
601 do_one (pool, if_rules) (gates, rule)
602 | null gates' = (pool, rule:if_rules)
603 | otherwise = ((gates',rule) : pool, if_rules)
605 gates' = filter (not . (`elemNameEnv` type_env)) gates
608 tcIfaceRule :: IfaceRule -> IfL IdCoreRule
609 tcIfaceRule (IfaceRule {ifRuleName = rule_name, ifActivation = act, ifRuleBndrs = bndrs,
610 ifRuleHead = fn_rdr, ifRuleArgs = args, ifRuleRhs = rhs })
611 = bindIfaceBndrs bndrs $ \ bndrs' ->
612 do { fn <- tcIfaceExtId fn_rdr
613 ; args' <- mappM tcIfaceExpr args
614 ; rhs' <- tcIfaceExpr rhs
615 ; returnM (fn, (Rule rule_name act bndrs' args' rhs')) }
617 tcIfaceRule (IfaceBuiltinRule fn_rdr core_rule)
618 = do { fn <- tcIfaceExtId fn_rdr
619 ; returnM (fn, core_rule) }
623 %************************************************************************
627 %************************************************************************
630 tcIfaceType :: IfaceType -> IfL Type
631 tcIfaceType (IfaceTyVar n) = do { tv <- tcIfaceTyVar n; return (TyVarTy tv) }
632 tcIfaceType (IfaceAppTy t1 t2) = do { t1' <- tcIfaceType t1; t2' <- tcIfaceType t2; return (AppTy t1' t2') }
633 tcIfaceType (IfaceFunTy t1 t2) = do { t1' <- tcIfaceType t1; t2' <- tcIfaceType t2; return (FunTy t1' t2') }
634 tcIfaceType (IfaceTyConApp tc ts) = do { tc' <- tcIfaceTyCon tc; ts' <- tcIfaceTypes ts; return (mkGenTyConApp tc' ts') }
635 tcIfaceType (IfaceForAllTy tv t) = bindIfaceTyVar tv $ \ tv' -> do { t' <- tcIfaceType t; return (ForAllTy tv' t') }
636 tcIfaceType (IfacePredTy st) = do { st' <- tcIfacePredType st; return (PredTy st') }
638 tcIfaceTypes tys = mapM tcIfaceType tys
640 -----------------------------------------
641 tcIfacePredType :: IfacePredType -> IfL PredType
642 tcIfacePredType (IfaceClassP cls ts) = do { cls' <- tcIfaceClass cls; ts' <- tcIfaceTypes ts; return (ClassP cls' ts') }
643 tcIfacePredType (IfaceIParam ip t) = do { ip' <- newIPName ip; t' <- tcIfaceType t; return (IParam ip' t') }
645 -----------------------------------------
646 tcIfaceCtxt :: IfaceContext -> IfL ThetaType
647 tcIfaceCtxt sts = mappM tcIfacePredType sts
651 %************************************************************************
655 %************************************************************************
658 tcIfaceExpr :: IfaceExpr -> IfL CoreExpr
659 tcIfaceExpr (IfaceType ty)
660 = tcIfaceType ty `thenM` \ ty' ->
663 tcIfaceExpr (IfaceLcl name)
664 = tcIfaceLclId name `thenM` \ id ->
667 tcIfaceExpr (IfaceExt gbl)
668 = tcIfaceExtId gbl `thenM` \ id ->
671 tcIfaceExpr (IfaceLit lit)
674 tcIfaceExpr (IfaceFCall cc ty)
675 = tcIfaceType ty `thenM` \ ty' ->
676 newUnique `thenM` \ u ->
677 returnM (Var (mkFCallId u cc ty'))
679 tcIfaceExpr (IfaceTuple boxity args)
680 = mappM tcIfaceExpr args `thenM` \ args' ->
682 -- Put the missing type arguments back in
683 con_args = map (Type . exprType) args' ++ args'
685 returnM (mkApps (Var con_id) con_args)
688 con_id = dataConWorkId (tupleCon boxity arity)
691 tcIfaceExpr (IfaceLam bndr body)
692 = bindIfaceBndr bndr $ \ bndr' ->
693 tcIfaceExpr body `thenM` \ body' ->
694 returnM (Lam bndr' body')
696 tcIfaceExpr (IfaceApp fun arg)
697 = tcIfaceExpr fun `thenM` \ fun' ->
698 tcIfaceExpr arg `thenM` \ arg' ->
699 returnM (App fun' arg')
701 tcIfaceExpr (IfaceCase scrut case_bndr alts)
702 = tcIfaceExpr scrut `thenM` \ scrut' ->
703 newIfaceName case_bndr `thenM` \ case_bndr_name ->
705 scrut_ty = exprType scrut'
706 case_bndr' = mkLocalId case_bndr_name scrut_ty
707 tc_app = splitTyConApp scrut_ty
708 -- NB: Won't always succeed (polymoprhic case)
709 -- but won't be demanded in those cases
710 -- NB: not tcSplitTyConApp; we are looking at Core here
711 -- look through non-rec newtypes to find the tycon that
712 -- corresponds to the datacon in this case alternative
714 extendIfaceIdEnv [case_bndr'] $
715 mappM (tcIfaceAlt tc_app) alts `thenM` \ alts' ->
716 returnM (Case scrut' case_bndr' alts')
718 tcIfaceExpr (IfaceLet (IfaceNonRec bndr rhs) body)
719 = tcIfaceExpr rhs `thenM` \ rhs' ->
720 bindIfaceId bndr $ \ bndr' ->
721 tcIfaceExpr body `thenM` \ body' ->
722 returnM (Let (NonRec bndr' rhs') body')
724 tcIfaceExpr (IfaceLet (IfaceRec pairs) body)
725 = bindIfaceIds bndrs $ \ bndrs' ->
726 mappM tcIfaceExpr rhss `thenM` \ rhss' ->
727 tcIfaceExpr body `thenM` \ body' ->
728 returnM (Let (Rec (bndrs' `zip` rhss')) body')
730 (bndrs, rhss) = unzip pairs
732 tcIfaceExpr (IfaceNote note expr)
733 = tcIfaceExpr expr `thenM` \ expr' ->
735 IfaceCoerce to_ty -> tcIfaceType to_ty `thenM` \ to_ty' ->
736 returnM (Note (Coerce to_ty'
737 (exprType expr')) expr')
738 IfaceInlineCall -> returnM (Note InlineCall expr')
739 IfaceInlineMe -> returnM (Note InlineMe expr')
740 IfaceSCC cc -> returnM (Note (SCC cc) expr')
741 IfaceCoreNote n -> returnM (Note (CoreNote n) expr')
743 -------------------------
744 tcIfaceAlt _ (IfaceDefault, names, rhs)
745 = ASSERT( null names )
746 tcIfaceExpr rhs `thenM` \ rhs' ->
747 returnM (DEFAULT, [], rhs')
749 tcIfaceAlt _ (IfaceLitAlt lit, names, rhs)
750 = ASSERT( null names )
751 tcIfaceExpr rhs `thenM` \ rhs' ->
752 returnM (LitAlt lit, [], rhs')
754 -- A case alternative is made quite a bit more complicated
755 -- by the fact that we omit type annotations because we can
756 -- work them out. True enough, but its not that easy!
757 tcIfaceAlt (tycon, inst_tys) (IfaceDataAlt data_occ, arg_occs, rhs)
759 tycon_mod = nameModuleName (tyConName tycon)
761 tcIfaceDataCon (ExtPkg tycon_mod data_occ) `thenM` \ con ->
762 newIfaceNames arg_occs `thenM` \ arg_names ->
764 ex_tyvars = dataConExistentialTyVars con
765 main_tyvars = tyConTyVars tycon
766 ex_tyvars' = [mkTyVar name (tyVarKind tv) | (name,tv) <- arg_names `zip` ex_tyvars]
767 ex_tys' = mkTyVarTys ex_tyvars'
768 arg_tys = dataConArgTys con (inst_tys ++ ex_tys')
769 id_names = dropList ex_tyvars arg_names
772 | not (equalLength id_names arg_tys)
773 = pprPanic "tcIfaceAlts" (ppr (con, arg_names, rhs) $$
774 (ppr main_tyvars <+> ppr ex_tyvars) $$
778 = zipWithEqual "tcIfaceAlts" mkLocalId id_names arg_tys
780 ASSERT2( con `elem` tyConDataCons tycon && equalLength inst_tys main_tyvars,
781 ppr con $$ ppr tycon $$ ppr (tyConDataCons tycon) $$ ppr arg_tys $$ ppr main_tyvars )
782 extendIfaceTyVarEnv ex_tyvars' $
783 extendIfaceIdEnv arg_ids $
784 tcIfaceExpr rhs `thenM` \ rhs' ->
785 returnM (DataAlt con, ex_tyvars' ++ arg_ids, rhs')
787 tcIfaceAlt (tycon, inst_tys) (IfaceTupleAlt boxity, arg_occs, rhs)
788 = newIfaceNames arg_occs `thenM` \ arg_names ->
790 [con] = tyConDataCons tycon
791 arg_ids = zipWithEqual "tcIfaceAlts" mkLocalId arg_names inst_tys
793 ASSERT( isTupleTyCon tycon )
794 extendIfaceIdEnv arg_ids $
795 tcIfaceExpr rhs `thenM` \ rhs' ->
796 returnM (DataAlt con, arg_ids, rhs')
801 tcExtCoreBindings :: Module -> [IfaceBinding] -> IfL [CoreBind] -- Used for external core
802 tcExtCoreBindings mod [] = return []
803 tcExtCoreBindings mod (b:bs) = do_one mod b (tcExtCoreBindings mod bs)
805 do_one :: Module -> IfaceBinding -> IfL [CoreBind] -> IfL [CoreBind]
806 do_one mod (IfaceNonRec bndr rhs) thing_inside
807 = do { rhs' <- tcIfaceExpr rhs
808 ; bndr' <- newExtCoreBndr mod bndr
809 ; extendIfaceIdEnv [bndr'] $ do
810 { core_binds <- thing_inside
811 ; return (NonRec bndr' rhs' : core_binds) }}
813 do_one mod (IfaceRec pairs) thing_inside
814 = do { bndrs' <- mappM (newExtCoreBndr mod) bndrs
815 ; extendIfaceIdEnv bndrs' $ do
816 { rhss' <- mappM tcIfaceExpr rhss
817 ; core_binds <- thing_inside
818 ; return (Rec (bndrs' `zip` rhss') : core_binds) }}
820 (bndrs,rhss) = unzip pairs
824 %************************************************************************
828 %************************************************************************
831 tcIdInfo name ty NoInfo = return vanillaIdInfo
832 tcIdInfo name ty DiscardedInfo = return vanillaIdInfo
833 tcIdInfo name ty (HasInfo iface_info)
834 = foldlM tcPrag init_info iface_info
836 -- Set the CgInfo to something sensible but uninformative before
837 -- we start; default assumption is that it has CAFs
838 init_info = vanillaIdInfo
840 tcPrag info HsNoCafRefs = returnM (info `setCafInfo` NoCafRefs)
841 tcPrag info (HsArity arity) = returnM (info `setArityInfo` arity)
842 tcPrag info (HsStrictness str) = returnM (info `setAllStrictnessInfo` Just str)
844 -- The next two are lazy, so they don't transitively suck stuff in
845 tcPrag info (HsWorker nm arity) = tcWorkerInfo ty info nm arity
846 tcPrag info (HsUnfold inline_prag expr)
847 = tcPragExpr name expr `thenM` \ maybe_expr' ->
849 -- maybe_expr' doesn't get looked at if the unfolding
850 -- is never inspected; so the typecheck doesn't even happen
851 unfold_info = case maybe_expr' of
852 Nothing -> noUnfolding
853 Just expr' -> mkTopUnfolding expr'
855 returnM (info `setUnfoldingInfoLazily` unfold_info
856 `setInlinePragInfo` inline_prag)
860 tcWorkerInfo ty info wkr_name arity
861 = do { mb_wkr_id <- forkM_maybe doc (tcIfaceExtId (LocalTop wkr_name))
863 -- We return without testing maybe_wkr_id, but as soon as info is
864 -- looked at we will test it. That's ok, because its outside the
865 -- knot; and there seems no big reason to further defer the
866 -- tcIfaceId lookup. (Contrast with tcPragExpr, where postponing walking
867 -- over the unfolding until it's actually used does seem worth while.)
868 ; us <- newUniqueSupply
870 ; returnM (case mb_wkr_id of
872 Just wkr_id -> add_wkr_info us wkr_id info) }
874 doc = text "Worker for" <+> ppr wkr_name
875 add_wkr_info us wkr_id info
876 = info `setUnfoldingInfoLazily` mk_unfolding us wkr_id
877 `setWorkerInfo` HasWorker wkr_id arity
879 mk_unfolding us wkr_id = mkTopUnfolding (initUs_ us (mkWrapper ty strict_sig) wkr_id)
881 -- We are relying here on strictness info always appearing
882 -- before worker info, fingers crossed ....
883 strict_sig = case newStrictnessInfo info of
885 Nothing -> pprPanic "Worker info but no strictness for" (ppr wkr_name)
888 For unfoldings we try to do the job lazily, so that we never type check
889 an unfolding that isn't going to be looked at.
892 tcPragExpr :: Name -> IfaceExpr -> IfL (Maybe CoreExpr)
895 tcIfaceExpr expr `thenM` \ core_expr' ->
897 -- Check for type consistency in the unfolding
898 ifOptM Opt_DoCoreLinting (
899 get_in_scope_ids `thenM` \ in_scope ->
900 case lintUnfolding noSrcLoc in_scope core_expr' of
901 Nothing -> returnM ()
902 Just fail_msg -> pprPanic "Iface Lint failure" (doc <+> fail_msg)
907 doc = text "Unfolding of" <+> ppr name
908 get_in_scope_ids -- Urgh; but just for linting
910 do { env <- getGblEnv
911 ; case if_rec_types env of {
912 Nothing -> return [] ;
913 Just (_, get_env) -> do
914 { type_env <- get_env
915 ; return (typeEnvIds type_env) }}}
920 %************************************************************************
924 %************************************************************************
927 bindIfaceBndr :: IfaceBndr -> (CoreBndr -> IfL a) -> IfL a
928 bindIfaceBndr (IfaceIdBndr bndr) thing_inside
929 = bindIfaceId bndr thing_inside
930 bindIfaceBndr (IfaceTvBndr bndr) thing_inside
931 = bindIfaceTyVar bndr thing_inside
933 bindIfaceBndrs :: [IfaceBndr] -> ([CoreBndr] -> IfL a) -> IfL a
934 bindIfaceBndrs [] thing_inside = thing_inside []
935 bindIfaceBndrs (b:bs) thing_inside
936 = bindIfaceBndr b $ \ b' ->
937 bindIfaceBndrs bs $ \ bs' ->
938 thing_inside (b':bs')
940 -----------------------
941 bindIfaceId :: (OccName, IfaceType) -> (Id -> IfL a) -> IfL a
942 bindIfaceId (occ, ty) thing_inside
943 = do { name <- newIfaceName occ
944 ; ty' <- tcIfaceType ty
945 ; let { id = mkLocalId name ty' }
946 ; extendIfaceIdEnv [id] (thing_inside id) }
948 bindIfaceIds :: [(OccName, IfaceType)] -> ([Id] -> IfL a) -> IfL a
949 bindIfaceIds bndrs thing_inside
950 = do { names <- newIfaceNames occs
951 ; tys' <- mappM tcIfaceType tys
952 ; let { ids = zipWithEqual "tcCoreValBndr" mkLocalId names tys' }
953 ; extendIfaceIdEnv ids (thing_inside ids) }
955 (occs,tys) = unzip bndrs
958 -----------------------
959 newExtCoreBndr :: Module -> (OccName, IfaceType) -> IfL Id
960 newExtCoreBndr mod (occ, ty)
961 = do { name <- newGlobalBinder mod occ Nothing noSrcLoc
962 ; ty' <- tcIfaceType ty
963 ; return (mkLocalId name ty') }
965 -----------------------
966 bindIfaceTyVar :: IfaceTvBndr -> (TyVar -> IfL a) -> IfL a
967 bindIfaceTyVar (occ,kind) thing_inside
968 = do { name <- newIfaceName occ
969 ; let tyvar = mk_iface_tyvar name kind
970 ; extendIfaceTyVarEnv [tyvar] (thing_inside tyvar) }
972 bindIfaceTyVars :: [IfaceTvBndr] -> ([TyVar] -> IfL a) -> IfL a
973 bindIfaceTyVars bndrs thing_inside
974 = do { names <- newIfaceNames occs
975 ; let tyvars = zipWith mk_iface_tyvar names kinds
976 ; extendIfaceTyVarEnv tyvars (thing_inside tyvars) }
978 (occs,kinds) = unzip bndrs
980 mk_iface_tyvar name kind = mkTyVar name kind