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, discardDeclPrags )
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,
22 mkAbstractTyConRhs, mkDataTyConRhs, mkNewTyConRhs )
24 import Type ( liftedTypeKind, splitTyConApp,
25 mkTyVarTys, mkGenTyConApp, mkTyVarTys, ThetaType, pprClassPred )
26 import TypeRep ( Type(..), PredType(..) )
27 import TyCon ( TyCon, tyConName )
28 import HscTypes ( ExternalPackageState(..), PackageInstEnv,
29 HscEnv, TyThing(..), implicitTyThings, typeEnvIds,
30 ModIface(..), ModDetails(..), InstPool, ModGuts,
31 TypeEnv, mkTypeEnv, extendTypeEnvList, lookupTypeEnv,
33 import InstEnv ( extendInstEnv )
35 import PprCore ( pprIdRules )
36 import Rules ( extendRuleBaseList )
37 import CoreUtils ( exprType )
39 import CoreLint ( lintUnfolding )
40 import WorkWrap ( mkWrapper )
41 import InstEnv ( DFunId )
42 import Id ( Id, mkVanillaGlobal, mkLocalId )
43 import MkId ( mkFCallId )
44 import IdInfo ( IdInfo, CafInfo(..), WorkerInfo(..),
45 setUnfoldingInfoLazily, setAllStrictnessInfo, setWorkerInfo,
46 setArityInfo, setInlinePragInfo, setCafInfo,
47 vanillaIdInfo, newStrictnessInfo )
48 import Class ( Class )
49 import TyCon ( tyConDataCons, tyConTyVars, isTupleTyCon, mkForeignTyCon )
50 import DataCon ( dataConWorkId, dataConExistentialTyVars, dataConArgTys )
51 import TysWiredIn ( tupleCon )
52 import Var ( TyVar, mkTyVar, tyVarKind )
53 import Name ( Name, NamedThing(..), nameModuleName, nameModule, nameOccName,
54 isWiredInName, wiredInNameTyThing_maybe, nameParent, nameParent_maybe )
56 import OccName ( OccName )
57 import Module ( Module, ModuleName, moduleName )
58 import UniqSupply ( initUs_ )
60 import SrcLoc ( noSrcLoc )
61 import Util ( zipWithEqual, dropList, equalLength, zipLazy )
62 import Maybes ( expectJust )
63 import CmdLineOpts ( DynFlag(..) )
72 An IfaceDecl is populated with RdrNames, and these are not renamed to
73 Names before typechecking, because there should be no scope errors etc.
75 -- For (b) consider: f = $(...h....)
76 -- where h is imported, and calls f via an hi-boot file.
77 -- This is bad! But it is not seen as a staging error, because h
78 -- is indeed imported. We don't want the type-checker to black-hole
79 -- when simplifying and compiling the splice!
81 -- Simple solution: discard any unfolding that mentions a variable
82 -- bound in this module (and hence not yet processed).
83 -- The discarding happens when forkM finds a type error.
85 %************************************************************************
87 %* tcImportDecl is the key function for "faulting in" *
90 %************************************************************************
92 The main idea is this. We are chugging along type-checking source code, and
93 find a reference to GHC.Base.map. We call tcLookupGlobal, which doesn't find
94 it in the EPS type envt. So it
96 2 gets the decl for GHC.Base.map
97 3 typechecks it via tcIfaceDecl
98 4 and adds it to the type env in the EPS
100 Note that DURING STEP 4, we may find that map's type mentions a type
101 constructor that also
103 Notice that for imported things we read the current version from the EPS
104 mutable variable. This is important in situations like
106 where the code that e1 expands to might import some defns that
107 also turn out to be needed by the code that e2 expands to.
110 tcImportDecl :: Name -> IfG TyThing
111 -- Get the TyThing for this Name from an interface file
114 -- Make sure the interface is loaded
115 ; let { nd_doc = ptext SLIT("Need decl for") <+> ppr name }
116 ; traceIf (nd_doc <+> char '{') -- Brace matches the later message
117 ; loadHomeInterface nd_doc name
119 -- Get the real name of the thing, with a correct nameParent field.
120 -- Before the interface is loaded, we may have a non-committal 'Nothing'
121 -- in the namePareent field (made up by IfaceEnv.lookupOrig), but
122 -- loading the interface updates the name cache.
123 -- We need the right nameParent field in getThing
124 ; real_name <- lookupOrig (nameModuleName name) (nameOccName name)
126 -- Get the decl out of the EPS
127 ; main_thing <- ASSERT( real_name == name ) -- Unique should not change!
130 -- Record the import in the type env,
131 -- slurp any rules it allows in
132 ; recordImportOf main_thing
134 ; let { extra | getName main_thing == real_name = empty
135 | otherwise = brackets (ptext SLIT("when seeking") <+> ppr real_name) }
136 ; traceIf (ptext SLIT(" ...imported decl for") <+> ppr main_thing <+> extra <+> char '}')
139 -- Look up the wanted Name in the type envt; it might be
140 -- one of the subordinate members of the input thing
141 ; if real_name == getName main_thing
142 then return main_thing
145 ; return (expectJust "tcImportDecl" $
146 lookupTypeEnv (eps_PTE eps) real_name) }}
148 recordImportOf :: TyThing -> IfG ()
149 -- Update the EPS to record the import of the Thing
150 -- (a) augment the type environment; this is done even for wired-in
151 -- things, so that we don't go through this rigmarole a second time
152 -- (b) slurp in any rules to maintain the invariant that any rule
153 -- whose gates are all in the type envt, is in eps_rule_base
156 = do { new_things <- updateEps (\ eps ->
157 let { new_things = thing : implicitTyThings thing
158 ; new_type_env = extendTypeEnvList (eps_PTE eps) new_things
159 -- NB: opportunity for a very subtle loop here!
160 -- If working out what the implicitTyThings are involves poking
161 -- any of the fork'd thunks in 'thing', then here's what happens
162 -- * recordImportOf succeed, extending type-env with a thunk
163 -- * the next guy to pull on type-env forces the thunk
164 -- * which pokes the suspended forks
165 -- * which, to execute, need to consult type-env (to check
166 -- entirely unrelated types, perhaps)
168 in (eps { eps_PTE = new_type_env }, new_things)
170 ; traceIf (text "tcImport: extend type env" <+> ppr new_things)
173 getThing :: Name -> IfG TyThing
174 -- Find and typecheck the thing; the Name might be a "subordinate name"
175 -- of the "main thing" (e.g. the constructor of a data type declaration)
176 -- The Thing we return is the parent "main thing"
179 | Just thing <- wiredInNameTyThing_maybe name
182 | otherwise = do -- The normal case, not wired in
183 { -- Get the decl from the pool
184 mb_decl <- updateEps (\ eps -> selectDecl eps name)
187 Just decl -> initIfaceLcl (nameModuleName name) (tcIfaceDecl decl)
189 -- Side-effects EPS by faulting in any needed decls
190 -- (via nested calls to tcImportDecl)
193 Nothing -> do { ioToIOEnv (printErrs (msg defaultErrStyle)); failM }
194 -- Declaration not found
195 -- No errors-var to accumulate errors in, so just
196 -- print out the error right now
200 msg = hang (ptext SLIT("Can't find interface-file declaration for") <+> ppr (nameParent name))
201 2 (vcat [ptext SLIT("Probable cause: bug in .hi-boot file, or inconsistent .hi file"),
202 ptext SLIT("Use -ddump-if-trace to get an idea of which file caused the error")])
204 selectDecl :: ExternalPackageState -> Name -> (ExternalPackageState, Maybe IfaceDecl)
205 -- Use nameParent to get the parent name of the thing
206 selectDecl eps@(EPS { eps_decls = Pool decls_map n_in n_out}) name
207 = case lookupNameEnv decls_map name of {
208 -- This first lookup will usually fail for subordinate names, because
209 -- the relevant decl is the parent decl.
210 -- But, if we export a data type decl abstractly, its selectors
211 -- get separate type signatures in the interface file
213 decls' = delFromNameEnv decls_map name
215 (eps {eps_decls = Pool decls' n_in (n_out+1)}, Just decl) ;
218 case nameParent_maybe name of {
219 Nothing -> (eps, Nothing ) ; -- No "parent"
220 Just main_name -> -- Has a parent; try that
222 case lookupNameEnv decls_map main_name of {
224 decls' = delFromNameEnv decls_map main_name
226 (eps {eps_decls = Pool decls' n_in (n_out+1)}, Just decl) ;
227 Nothing -> (eps, Nothing)
231 %************************************************************************
233 Type-checking a complete interface
235 %************************************************************************
237 Suppose we discover we don't need to recompile. Then we must type
238 check the old interface file. This is a bit different to the
239 incremental type checking we do as we suck in interface files. Instead
240 we do things similarly as when we are typechecking source decls: we
241 bring into scope the type envt for the interface all at once, using a
242 knot. Remember, the decls aren't necessarily in dependency order --
243 and even if they were, the type decls might be mutually recursive.
246 typecheckIface :: HscEnv
247 -> ModIface -- Get the decls from here
249 typecheckIface hsc_env iface
250 = initIfaceTc hsc_env iface $ \ tc_env_var -> do
251 { -- Get the right set of decls and rules. If we are compiling without -O
252 -- we discard pragmas before typechecking, so that we don't "see"
253 -- information that we shouldn't. From a versioning point of view
254 -- It's not actually *wrong* to do so, but in fact GHCi is unable
255 -- to handle unboxed tuples, so it must not see unfoldings.
256 ignore_prags <- doptM Opt_IgnoreInterfacePragmas
257 ; let { decls | ignore_prags = map (discardDeclPrags . snd) (mi_decls iface)
258 | otherwise = map snd (mi_decls iface)
259 ; rules | ignore_prags = []
260 | otherwise = mi_rules iface
261 ; dfuns = mi_insts iface
262 ; mod_name = moduleName (mi_module iface)
264 -- Typecheck the decls
265 ; names <- mappM (lookupOrig mod_name . ifName) decls
266 ; ty_things <- fixM (\ rec_ty_things -> do
267 { writeMutVar tc_env_var (mkNameEnv (names `zipLazy` rec_ty_things))
268 -- This only makes available the "main" things,
269 -- but that's enough for the strictly-checked part
270 ; mapM tcIfaceDecl decls })
272 -- Now augment the type envt with all the implicit things
273 -- These will be needed when type-checking the unfoldings for
274 -- the IfaceIds, but this is done lazily, so writing the thing
276 ; let { add_implicits main_thing = main_thing : implicitTyThings main_thing
277 ; type_env = mkTypeEnv (concatMap add_implicits ty_things) }
278 ; writeMutVar tc_env_var type_env
280 -- Now do those rules and instances
281 ; dfuns <- mapM tcIfaceInst dfuns
282 ; rules <- mapM tcIfaceRule rules
285 ; return (ModDetails { md_types = type_env, md_insts = dfuns, md_rules = rules })
290 %************************************************************************
292 Type and class declarations
294 %************************************************************************
296 When typechecking a data type decl, we *lazily* (via forkM) typecheck
297 the constructor argument types. This is in the hope that we may never
298 poke on those argument types, and hence may never need to load the
299 interface files for types mentioned in the arg types.
302 data Foo.S = MkS Baz.T
303 Mabye we can get away without even loading the interface for Baz!
305 This is not just a performance thing. Suppose we have
306 data Foo.S = MkS Baz.T
307 data Baz.T = MkT Foo.S
308 (in different interface files, of course).
309 Now, first we load and typecheck Foo.S, and add it to the type envt.
310 If we do explore MkS's argument, we'll load and typecheck Baz.T.
311 If we explore MkT's argument we'll find Foo.S already in the envt.
313 If we typechecked constructor args eagerly, when loading Foo.S we'd try to
314 typecheck the type Baz.T. So we'd fault in Baz.T... and then need Foo.S...
315 which isn't done yet.
317 All very cunning. However, there is a rather subtle gotcha which bit
318 me when developing this stuff. When we typecheck the decl for S, we
319 extend the type envt with S, MkS, and all its implicit Ids. Suppose
320 (a bug, but it happened) that the list of implicit Ids depended in
321 turn on the constructor arg types. Then the following sequence of
323 * we build a thunk <t> for the constructor arg tys
324 * we build a thunk for the extended type environment (depends on <t>)
325 * we write the extended type envt into the global EPS mutvar
327 Now we look something up in the type envt
329 * which reads the global type envt out of the global EPS mutvar
330 * but that depends in turn on <t>
332 It's subtle, because, it'd work fine if we typechecked the constructor args
333 eagerly -- they don't need the extended type envt. They just get the extended
334 type envt by accident, because they look at it later.
336 What this means is that the implicitTyThings MUST NOT DEPEND on any of
341 tcIfaceDecl :: IfaceDecl -> IfL TyThing
343 tcIfaceDecl (IfaceId {ifName = occ_name, ifType = iface_type, ifIdInfo = info})
344 = do { name <- lookupIfaceTop occ_name
345 ; ty <- tcIfaceType iface_type
346 ; info <- tcIdInfo name ty info
347 ; return (AnId (mkVanillaGlobal name ty info)) }
349 tcIfaceDecl (IfaceData {ifName = occ_name,
350 ifTyVars = tv_bndrs, ifCtxt = rdr_ctxt,
352 ifVrcs = arg_vrcs, ifRec = is_rec,
353 ifGeneric = want_generic })
354 = do { tc_name <- lookupIfaceTop occ_name
355 ; bindIfaceTyVars tv_bndrs $ \ tyvars -> do
357 { traceIf (text "tcIfaceDecl" <+> ppr rdr_ctxt)
359 ; ctxt <- forkM (ptext SLIT("Ctxt of data decl") <+> ppr tc_name) $
361 -- The reason for laziness here is to postpone
362 -- looking at the context, because the class may not
363 -- be in the type envt yet. E.g.
364 -- class Real a where { toRat :: a -> Ratio Integer }
365 -- data (Real a) => Ratio a = ...
366 -- We suck in the decl for Real, and type check it, which sucks
367 -- in the data type Ratio; but we must postpone typechecking the
370 ; tycon <- fixM ( \ tycon -> do
371 { cons <- tcIfaceDataCons tycon tyvars ctxt rdr_cons
372 ; tycon <- buildAlgTyCon tc_name tyvars ctxt cons
373 arg_vrcs is_rec want_generic
376 ; traceIf (text "tcIfaceDecl4" <+> ppr tycon)
377 ; return (ATyCon tycon)
380 tcIfaceDecl (IfaceSyn {ifName = occ_name, ifTyVars = tv_bndrs,
381 ifSynRhs = rdr_rhs_ty, ifVrcs = arg_vrcs})
382 = bindIfaceTyVars tv_bndrs $ \ tyvars -> do
383 { tc_name <- lookupIfaceTop occ_name
384 ; rhs_ty <- tcIfaceType rdr_rhs_ty
385 ; return (ATyCon (buildSynTyCon tc_name tyvars rhs_ty arg_vrcs))
388 tcIfaceDecl (IfaceClass {ifCtxt = rdr_ctxt, ifName = occ_name, ifTyVars = tv_bndrs,
389 ifFDs = rdr_fds, ifSigs = rdr_sigs,
390 ifVrcs = tc_vrcs, ifRec = tc_isrec })
391 = bindIfaceTyVars tv_bndrs $ \ tyvars -> do
392 { cls_name <- lookupIfaceTop occ_name
393 ; ctxt <- tcIfaceCtxt rdr_ctxt
394 ; sigs <- mappM tc_sig rdr_sigs
395 ; fds <- mappM tc_fd rdr_fds
396 ; cls <- buildClass cls_name tyvars ctxt fds sigs tc_isrec tc_vrcs
397 ; return (AClass cls) }
399 tc_sig (IfaceClassOp occ dm rdr_ty)
400 = do { op_name <- lookupIfaceTop occ
401 ; op_ty <- forkM (mk_doc op_name rdr_ty) (tcIfaceType rdr_ty)
402 -- Must be done lazily for just the same reason as the
403 -- context of a data decl: the type sig might mention the
404 -- class being defined
405 ; return (op_name, dm, op_ty) }
407 mk_doc op_name op_ty = ptext SLIT("Class op") <+> sep [ppr op_name, ppr op_ty]
409 tc_fd (tvs1, tvs2) = do { tvs1' <- mappM tcIfaceTyVar tvs1
410 ; tvs2' <- mappM tcIfaceTyVar tvs2
411 ; return (tvs1', tvs2') }
413 tcIfaceDecl (IfaceForeign {ifName = rdr_name, ifExtName = ext_name})
414 = do { name <- lookupIfaceTop rdr_name
415 ; return (ATyCon (mkForeignTyCon name ext_name
416 liftedTypeKind 0 [])) }
418 tcIfaceDataCons tycon tyvars ctxt if_cons
420 IfAbstractTyCon -> return mkAbstractTyConRhs
421 IfDataTyCon cons -> do { data_cons <- mappM tc_con_decl cons
422 ; return (mkDataTyConRhs data_cons) }
423 IfNewTyCon con -> do { data_con <- tc_con_decl con
424 ; return (mkNewTyConRhs data_con) }
426 tc_con_decl (IfaceConDecl occ ex_tvs ex_ctxt args stricts field_lbls)
427 = bindIfaceTyVars ex_tvs $ \ ex_tyvars -> do
428 { name <- lookupIfaceTop occ
429 ; ex_theta <- tcIfaceCtxt ex_ctxt -- Laziness seems not worth the bother here
431 -- Read the argument types, but lazily to avoid faulting in
432 -- the component types unless they are really needed
433 ; arg_tys <- forkM (mk_doc name args) (mappM tcIfaceType args) ;
435 ; lbl_names <- mappM lookupIfaceTop field_lbls
437 ; buildDataCon name stricts lbl_names
438 tyvars ctxt ex_tyvars ex_theta
441 mk_doc con_name args = ptext SLIT("Constructor") <+> sep [ppr con_name, ppr args]
445 %************************************************************************
449 %************************************************************************
451 The gating story for instance declarations
452 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
453 When we are looking for a dict (C t1..tn), we slurp in instance decls for
455 mention at least one of the type constructors
456 at the roots of t1..tn
458 Why "at least one" rather than "all"? Because functional dependencies
459 complicate the picture. Consider
460 class C a b | a->b where ...
461 instance C Foo Baz where ...
462 Here, the gates are really only C and Foo, *not* Baz.
463 That is, if C and Foo are visible, even if Baz isn't, we must
464 slurp the decl, even if Baz is thus far completely unknown to the
467 Why "roots of the types"? Reason is overlap. For example, suppose there
468 are interfaces in the pool for
472 Then, if we are trying to resolve (C Int x), we need (a)
473 if we are trying to resolve (C x [y]), we need *both* (b) and (c),
474 even though T is not involved yet, so that we spot the overlap.
477 NOTE: if you use an instance decl with NO type constructors
478 instance C a where ...
479 and look up an Inst that only has type variables such as (C (n o))
480 then GHC won't necessarily suck in the instances that overlap with this.
484 loadImportedInsts :: Class -> [Type] -> TcM PackageInstEnv
485 loadImportedInsts cls tys
486 = do { -- Get interfaces for wired-in things, such as Integer
487 -- Any non-wired-in tycons will already be loaded, else
488 -- we couldn't have them in the Type
489 ; this_mod <- getModule
490 ; let { (cls_gate, tc_gates) = predInstGates cls tys
491 ; imp_wi n = isWiredInName n && this_mod /= nameModule n
492 ; wired_tcs = filter imp_wi tc_gates }
493 -- Wired-in tycons not from this module. The "this-module"
494 -- test bites only when compiling Base etc, because loadHomeInterface
495 -- barfs if it's asked to load a non-existent interface
496 ; if null wired_tcs then returnM ()
497 else initIfaceTcRn (mapM_ (loadHomeInterface wired_doc) wired_tcs)
499 ; eps_var <- getEpsVar
500 ; eps <- readMutVar eps_var
502 -- For interest: report the no-type-constructor case.
503 -- Don't report when -fallow-undecidable-instances is on, because then
504 -- we call loadImportedInsts when looking up even predicates like (C a)
505 -- But without undecidable instances it's rare to see C (a b) and
506 -- somethat interesting
507 {- (comment out; happens a lot in some code)
510 ; WARN( not (dopt Opt_AllowUndecidableInstances dflags) && null tc_gates,
511 ptext SLIT("Interesting! No tycons in Inst:")
512 <+> pprClassPred cls tys )
516 -- Suck in the instances
517 ; let { (inst_pool', iface_insts)
518 = selectInsts (eps_insts eps) cls_gate tc_gates }
520 -- Empty => finish up rapidly, without writing to eps
521 ; if null iface_insts then
522 return (eps_inst_env eps)
524 { writeMutVar eps_var (eps {eps_insts = inst_pool'})
526 ; traceIf (sep [ptext SLIT("Importing instances for") <+> pprClassPred cls tys,
527 nest 2 (vcat (map ppr iface_insts))])
529 -- Typecheck the new instances
530 ; dfuns <- initIfaceTcRn (mappM tc_inst iface_insts)
532 -- And put them in the package instance environment
533 ; updateEps ( \ eps ->
535 inst_env' = foldl extendInstEnv (eps_inst_env eps) dfuns
537 (eps { eps_inst_env = inst_env' }, inst_env')
540 wired_doc = ptext SLIT("Need home inteface for wired-in thing")
542 tc_inst (mod, inst) = initIfaceLcl mod (tcIfaceInst inst)
544 tcIfaceInst :: IfaceInst -> IfL DFunId
545 tcIfaceInst (IfaceInst { ifDFun = dfun_occ })
546 = tcIfaceExtId (LocalTop dfun_occ)
548 selectInsts :: InstPool -> Name -> [Name] -> (InstPool, [(ModuleName, IfaceInst)])
549 selectInsts pool@(Pool insts n_in n_out) cls tycons
550 = (Pool insts' n_in (n_out + length iface_insts), iface_insts)
552 (insts', iface_insts)
553 = case lookupNameEnv insts cls of {
554 Nothing -> (insts, []) ;
557 case choose1 gated_insts of {
558 (_, []) -> (insts, []) ; -- None picked
559 (gated_insts', iface_insts') ->
561 (extendNameEnv insts cls gated_insts', iface_insts') }}
564 | null tycons -- Bizarre special case of C (a b); then there are no tycons
565 = ([], map snd gated_insts) -- Just grab all the instances, no real alternative
566 | otherwise -- Normal case
567 = foldl choose2 ([],[]) gated_insts
569 -- Reverses the gated decls, but that doesn't matter
570 choose2 (gis, decls) (gates, decl)
571 | null gates -- Happens when we have 'instance T a where ...'
572 || any (`elem` tycons) gates = (gis, decl:decls)
573 | otherwise = ((gates,decl) : gis, decls)
576 %************************************************************************
580 %************************************************************************
582 We move a IfaceRule from eps_rules to eps_rule_base when all its LHS free vars
583 are in the type environment. However, remember that typechecking a Rule may
584 (as a side effect) augment the type envt, and so we may need to iterate the process.
587 loadImportedRules :: HscEnv -> ModGuts -> IO [IdCoreRule]
588 -- Returns just the new rules added
589 loadImportedRules hsc_env guts
590 = initIfaceRules hsc_env guts $ do
592 if_rules <- updateEps (\ eps ->
593 let { (new_pool, if_rules) = selectRules (eps_rules eps) (eps_PTE eps) }
594 in (eps { eps_rules = new_pool }, if_rules) )
596 ; traceIf (ptext SLIT("Importing rules:") <+> vcat (map ppr if_rules))
598 ; let tc_rule (mod, rule) = initIfaceLcl mod (tcIfaceRule rule)
599 ; core_rules <- mapM tc_rule if_rules
602 ; traceIf (ptext SLIT("Imported rules:") <+> pprIdRules core_rules)
604 -- Update the rule base and return it
605 ; updateEps (\ eps ->
606 let { new_rule_base = extendRuleBaseList (eps_rule_base eps) core_rules }
607 in (eps { eps_rule_base = new_rule_base }, new_rule_base)
610 -- Strictly speaking, at this point we should go round again, since
611 -- typechecking one set of rules may bring in new things which enable
612 -- some more rules to come in. But we call loadImportedRules several
613 -- times anyway, so I'm going to be lazy and ignore this.
618 selectRules :: RulePool -> TypeEnv -> (RulePool, [(ModuleName, IfaceRule)])
619 -- Not terribly efficient. Look at each rule in the pool to see if
620 -- all its gates are in the type env. If so, take it out of the pool.
621 -- If not, trim its gates for next time.
622 selectRules (Pool rules n_in n_out) type_env
623 = (Pool rules' n_in (n_out + length if_rules), if_rules)
625 (rules', if_rules) = foldl do_one ([], []) rules
627 do_one (pool, if_rules) (gates, rule)
628 | null gates' = (pool, rule:if_rules)
629 | otherwise = ((gates',rule) : pool, if_rules)
631 gates' = filter (not . (`elemNameEnv` type_env)) gates
634 tcIfaceRule :: IfaceRule -> IfL IdCoreRule
635 tcIfaceRule (IfaceRule {ifRuleName = rule_name, ifActivation = act, ifRuleBndrs = bndrs,
636 ifRuleHead = fn_rdr, ifRuleArgs = args, ifRuleRhs = rhs })
637 = bindIfaceBndrs bndrs $ \ bndrs' ->
638 do { fn <- tcIfaceExtId fn_rdr
639 ; args' <- mappM tcIfaceExpr args
640 ; rhs' <- tcIfaceExpr rhs
641 ; returnM (fn, (Rule rule_name act bndrs' args' rhs')) }
643 tcIfaceRule (IfaceBuiltinRule fn_rdr core_rule)
644 = do { fn <- tcIfaceExtId fn_rdr
645 ; returnM (fn, core_rule) }
649 %************************************************************************
653 %************************************************************************
656 tcIfaceType :: IfaceType -> IfL Type
657 tcIfaceType (IfaceTyVar n) = do { tv <- tcIfaceTyVar n; return (TyVarTy tv) }
658 tcIfaceType (IfaceAppTy t1 t2) = do { t1' <- tcIfaceType t1; t2' <- tcIfaceType t2; return (AppTy t1' t2') }
659 tcIfaceType (IfaceFunTy t1 t2) = do { t1' <- tcIfaceType t1; t2' <- tcIfaceType t2; return (FunTy t1' t2') }
660 tcIfaceType (IfaceTyConApp tc ts) = do { tc' <- tcIfaceTyCon tc; ts' <- tcIfaceTypes ts; return (mkGenTyConApp tc' ts') }
661 tcIfaceType (IfaceForAllTy tv t) = bindIfaceTyVar tv $ \ tv' -> do { t' <- tcIfaceType t; return (ForAllTy tv' t') }
662 tcIfaceType (IfacePredTy st) = do { st' <- tcIfacePredType st; return (PredTy st') }
664 tcIfaceTypes tys = mapM tcIfaceType tys
666 -----------------------------------------
667 tcIfacePredType :: IfacePredType -> IfL PredType
668 tcIfacePredType (IfaceClassP cls ts) = do { cls' <- tcIfaceClass cls; ts' <- tcIfaceTypes ts; return (ClassP cls' ts') }
669 tcIfacePredType (IfaceIParam ip t) = do { ip' <- newIPName ip; t' <- tcIfaceType t; return (IParam ip' t') }
671 -----------------------------------------
672 tcIfaceCtxt :: IfaceContext -> IfL ThetaType
673 tcIfaceCtxt sts = mappM tcIfacePredType sts
677 %************************************************************************
681 %************************************************************************
684 tcIfaceExpr :: IfaceExpr -> IfL CoreExpr
685 tcIfaceExpr (IfaceType ty)
686 = tcIfaceType ty `thenM` \ ty' ->
689 tcIfaceExpr (IfaceLcl name)
690 = tcIfaceLclId name `thenM` \ id ->
693 tcIfaceExpr (IfaceExt gbl)
694 = tcIfaceExtId gbl `thenM` \ id ->
697 tcIfaceExpr (IfaceLit lit)
700 tcIfaceExpr (IfaceFCall cc ty)
701 = tcIfaceType ty `thenM` \ ty' ->
702 newUnique `thenM` \ u ->
703 returnM (Var (mkFCallId u cc ty'))
705 tcIfaceExpr (IfaceTuple boxity args)
706 = mappM tcIfaceExpr args `thenM` \ args' ->
708 -- Put the missing type arguments back in
709 con_args = map (Type . exprType) args' ++ args'
711 returnM (mkApps (Var con_id) con_args)
714 con_id = dataConWorkId (tupleCon boxity arity)
717 tcIfaceExpr (IfaceLam bndr body)
718 = bindIfaceBndr bndr $ \ bndr' ->
719 tcIfaceExpr body `thenM` \ body' ->
720 returnM (Lam bndr' body')
722 tcIfaceExpr (IfaceApp fun arg)
723 = tcIfaceExpr fun `thenM` \ fun' ->
724 tcIfaceExpr arg `thenM` \ arg' ->
725 returnM (App fun' arg')
727 tcIfaceExpr (IfaceCase scrut case_bndr alts)
728 = tcIfaceExpr scrut `thenM` \ scrut' ->
729 newIfaceName case_bndr `thenM` \ case_bndr_name ->
731 scrut_ty = exprType scrut'
732 case_bndr' = mkLocalId case_bndr_name scrut_ty
733 tc_app = splitTyConApp scrut_ty
734 -- NB: Won't always succeed (polymoprhic case)
735 -- but won't be demanded in those cases
736 -- NB: not tcSplitTyConApp; we are looking at Core here
737 -- look through non-rec newtypes to find the tycon that
738 -- corresponds to the datacon in this case alternative
740 extendIfaceIdEnv [case_bndr'] $
741 mappM (tcIfaceAlt tc_app) alts `thenM` \ alts' ->
742 returnM (Case scrut' case_bndr' alts')
744 tcIfaceExpr (IfaceLet (IfaceNonRec bndr rhs) body)
745 = tcIfaceExpr rhs `thenM` \ rhs' ->
746 bindIfaceId bndr $ \ bndr' ->
747 tcIfaceExpr body `thenM` \ body' ->
748 returnM (Let (NonRec bndr' rhs') body')
750 tcIfaceExpr (IfaceLet (IfaceRec pairs) body)
751 = bindIfaceIds bndrs $ \ bndrs' ->
752 mappM tcIfaceExpr rhss `thenM` \ rhss' ->
753 tcIfaceExpr body `thenM` \ body' ->
754 returnM (Let (Rec (bndrs' `zip` rhss')) body')
756 (bndrs, rhss) = unzip pairs
758 tcIfaceExpr (IfaceNote note expr)
759 = tcIfaceExpr expr `thenM` \ expr' ->
761 IfaceCoerce to_ty -> tcIfaceType to_ty `thenM` \ to_ty' ->
762 returnM (Note (Coerce to_ty'
763 (exprType expr')) expr')
764 IfaceInlineCall -> returnM (Note InlineCall expr')
765 IfaceInlineMe -> returnM (Note InlineMe expr')
766 IfaceSCC cc -> returnM (Note (SCC cc) expr')
767 IfaceCoreNote n -> returnM (Note (CoreNote n) expr')
769 -------------------------
770 tcIfaceAlt _ (IfaceDefault, names, rhs)
771 = ASSERT( null names )
772 tcIfaceExpr rhs `thenM` \ rhs' ->
773 returnM (DEFAULT, [], rhs')
775 tcIfaceAlt _ (IfaceLitAlt lit, names, rhs)
776 = ASSERT( null names )
777 tcIfaceExpr rhs `thenM` \ rhs' ->
778 returnM (LitAlt lit, [], rhs')
780 -- A case alternative is made quite a bit more complicated
781 -- by the fact that we omit type annotations because we can
782 -- work them out. True enough, but its not that easy!
783 tcIfaceAlt (tycon, inst_tys) (IfaceDataAlt data_occ, arg_occs, rhs)
785 tycon_mod = nameModuleName (tyConName tycon)
787 tcIfaceDataCon (ExtPkg tycon_mod data_occ) `thenM` \ con ->
788 newIfaceNames arg_occs `thenM` \ arg_names ->
790 ex_tyvars = dataConExistentialTyVars con
791 main_tyvars = tyConTyVars tycon
792 ex_tyvars' = [mkTyVar name (tyVarKind tv) | (name,tv) <- arg_names `zip` ex_tyvars]
793 ex_tys' = mkTyVarTys ex_tyvars'
794 arg_tys = dataConArgTys con (inst_tys ++ ex_tys')
795 id_names = dropList ex_tyvars arg_names
798 | not (equalLength id_names arg_tys)
799 = pprPanic "tcIfaceAlts" (ppr (con, arg_names, rhs) $$
800 (ppr main_tyvars <+> ppr ex_tyvars) $$
804 = zipWithEqual "tcIfaceAlts" mkLocalId id_names arg_tys
806 ASSERT2( con `elem` tyConDataCons tycon && equalLength inst_tys main_tyvars,
807 ppr con $$ ppr tycon $$ ppr (tyConDataCons tycon) $$ ppr arg_tys $$ ppr main_tyvars )
808 extendIfaceTyVarEnv ex_tyvars' $
809 extendIfaceIdEnv arg_ids $
810 tcIfaceExpr rhs `thenM` \ rhs' ->
811 returnM (DataAlt con, ex_tyvars' ++ arg_ids, rhs')
813 tcIfaceAlt (tycon, inst_tys) (IfaceTupleAlt boxity, arg_occs, rhs)
814 = newIfaceNames arg_occs `thenM` \ arg_names ->
816 [con] = tyConDataCons tycon
817 arg_ids = zipWithEqual "tcIfaceAlts" mkLocalId arg_names inst_tys
819 ASSERT( isTupleTyCon tycon )
820 extendIfaceIdEnv arg_ids $
821 tcIfaceExpr rhs `thenM` \ rhs' ->
822 returnM (DataAlt con, arg_ids, rhs')
827 tcExtCoreBindings :: Module -> [IfaceBinding] -> IfL [CoreBind] -- Used for external core
828 tcExtCoreBindings mod [] = return []
829 tcExtCoreBindings mod (b:bs) = do_one mod b (tcExtCoreBindings mod bs)
831 do_one :: Module -> IfaceBinding -> IfL [CoreBind] -> IfL [CoreBind]
832 do_one mod (IfaceNonRec bndr rhs) thing_inside
833 = do { rhs' <- tcIfaceExpr rhs
834 ; bndr' <- newExtCoreBndr mod bndr
835 ; extendIfaceIdEnv [bndr'] $ do
836 { core_binds <- thing_inside
837 ; return (NonRec bndr' rhs' : core_binds) }}
839 do_one mod (IfaceRec pairs) thing_inside
840 = do { bndrs' <- mappM (newExtCoreBndr mod) bndrs
841 ; extendIfaceIdEnv bndrs' $ do
842 { rhss' <- mappM tcIfaceExpr rhss
843 ; core_binds <- thing_inside
844 ; return (Rec (bndrs' `zip` rhss') : core_binds) }}
846 (bndrs,rhss) = unzip pairs
850 %************************************************************************
854 %************************************************************************
857 tcIdInfo :: Name -> Type -> IfaceIdInfo -> IfL IdInfo
858 tcIdInfo name ty NoInfo = return vanillaIdInfo
859 tcIdInfo name ty (HasInfo info) = foldlM tcPrag init_info info
861 -- Set the CgInfo to something sensible but uninformative before
862 -- we start; default assumption is that it has CAFs
863 init_info = vanillaIdInfo
865 tcPrag info HsNoCafRefs = returnM (info `setCafInfo` NoCafRefs)
866 tcPrag info (HsArity arity) = returnM (info `setArityInfo` arity)
867 tcPrag info (HsStrictness str) = returnM (info `setAllStrictnessInfo` Just str)
869 -- The next two are lazy, so they don't transitively suck stuff in
870 tcPrag info (HsWorker nm arity) = tcWorkerInfo ty info nm arity
871 tcPrag info (HsUnfold inline_prag expr)
872 = tcPragExpr name expr `thenM` \ maybe_expr' ->
874 -- maybe_expr' doesn't get looked at if the unfolding
875 -- is never inspected; so the typecheck doesn't even happen
876 unfold_info = case maybe_expr' of
877 Nothing -> noUnfolding
878 Just expr' -> mkTopUnfolding expr'
880 returnM (info `setUnfoldingInfoLazily` unfold_info
881 `setInlinePragInfo` inline_prag)
885 tcWorkerInfo ty info wkr arity
886 = do { mb_wkr_id <- forkM_maybe doc (tcIfaceExtId wkr)
888 -- We return without testing maybe_wkr_id, but as soon as info is
889 -- looked at we will test it. That's ok, because its outside the
890 -- knot; and there seems no big reason to further defer the
891 -- tcIfaceId lookup. (Contrast with tcPragExpr, where postponing walking
892 -- over the unfolding until it's actually used does seem worth while.)
893 ; us <- newUniqueSupply
895 ; returnM (case mb_wkr_id of
897 Just wkr_id -> add_wkr_info us wkr_id info) }
899 doc = text "Worker for" <+> ppr wkr
900 add_wkr_info us wkr_id info
901 = info `setUnfoldingInfoLazily` mk_unfolding us wkr_id
902 `setWorkerInfo` HasWorker wkr_id arity
904 mk_unfolding us wkr_id = mkTopUnfolding (initUs_ us (mkWrapper ty strict_sig) wkr_id)
906 -- We are relying here on strictness info always appearing
907 -- before worker info, fingers crossed ....
908 strict_sig = case newStrictnessInfo info of
910 Nothing -> pprPanic "Worker info but no strictness for" (ppr wkr)
913 For unfoldings we try to do the job lazily, so that we never type check
914 an unfolding that isn't going to be looked at.
917 tcPragExpr :: Name -> IfaceExpr -> IfL (Maybe CoreExpr)
920 tcIfaceExpr expr `thenM` \ core_expr' ->
922 -- Check for type consistency in the unfolding
923 ifOptM Opt_DoCoreLinting (
924 get_in_scope_ids `thenM` \ in_scope ->
925 case lintUnfolding noSrcLoc in_scope core_expr' of
926 Nothing -> returnM ()
927 Just fail_msg -> pprPanic "Iface Lint failure" (doc <+> fail_msg)
932 doc = text "Unfolding of" <+> ppr name
933 get_in_scope_ids -- Urgh; but just for linting
935 do { env <- getGblEnv
936 ; case if_rec_types env of {
937 Nothing -> return [] ;
938 Just (_, get_env) -> do
939 { type_env <- get_env
940 ; return (typeEnvIds type_env) }}}
945 %************************************************************************
949 %************************************************************************
952 bindIfaceBndr :: IfaceBndr -> (CoreBndr -> IfL a) -> IfL a
953 bindIfaceBndr (IfaceIdBndr bndr) thing_inside
954 = bindIfaceId bndr thing_inside
955 bindIfaceBndr (IfaceTvBndr bndr) thing_inside
956 = bindIfaceTyVar bndr thing_inside
958 bindIfaceBndrs :: [IfaceBndr] -> ([CoreBndr] -> IfL a) -> IfL a
959 bindIfaceBndrs [] thing_inside = thing_inside []
960 bindIfaceBndrs (b:bs) thing_inside
961 = bindIfaceBndr b $ \ b' ->
962 bindIfaceBndrs bs $ \ bs' ->
963 thing_inside (b':bs')
965 -----------------------
966 bindIfaceId :: (OccName, IfaceType) -> (Id -> IfL a) -> IfL a
967 bindIfaceId (occ, ty) thing_inside
968 = do { name <- newIfaceName occ
969 ; ty' <- tcIfaceType ty
970 ; let { id = mkLocalId name ty' }
971 ; extendIfaceIdEnv [id] (thing_inside id) }
973 bindIfaceIds :: [(OccName, IfaceType)] -> ([Id] -> IfL a) -> IfL a
974 bindIfaceIds bndrs thing_inside
975 = do { names <- newIfaceNames occs
976 ; tys' <- mappM tcIfaceType tys
977 ; let { ids = zipWithEqual "tcCoreValBndr" mkLocalId names tys' }
978 ; extendIfaceIdEnv ids (thing_inside ids) }
980 (occs,tys) = unzip bndrs
983 -----------------------
984 newExtCoreBndr :: Module -> (OccName, IfaceType) -> IfL Id
985 newExtCoreBndr mod (occ, ty)
986 = do { name <- newGlobalBinder mod occ Nothing noSrcLoc
987 ; ty' <- tcIfaceType ty
988 ; return (mkLocalId name ty') }
990 -----------------------
991 bindIfaceTyVar :: IfaceTvBndr -> (TyVar -> IfL a) -> IfL a
992 bindIfaceTyVar (occ,kind) thing_inside
993 = do { name <- newIfaceName occ
994 ; let tyvar = mk_iface_tyvar name kind
995 ; extendIfaceTyVarEnv [tyvar] (thing_inside tyvar) }
997 bindIfaceTyVars :: [IfaceTvBndr] -> ([TyVar] -> IfL a) -> IfL a
998 bindIfaceTyVars bndrs thing_inside
999 = do { names <- newIfaceNames occs
1000 ; let tyvars = zipWith mk_iface_tyvar names kinds
1001 ; extendIfaceTyVarEnv tyvars (thing_inside tyvars) }
1003 (occs,kinds) = unzip bndrs
1005 mk_iface_tyvar name kind = mkTyVar name kind