2 % (c) The University of Glasgow 2006
3 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
6 Type checking of type signatures in interface files
10 tcImportDecl, checkWiredInTyCon, tcHiBootIface, typecheckIface,
11 tcIfaceDecl, tcIfaceInst, tcIfaceFamInst, tcIfaceRules, tcIfaceGlobal,
15 #include "HsVersions.h"
65 An IfaceDecl is populated with RdrNames, and these are not renamed to
66 Names before typechecking, because there should be no scope errors etc.
68 -- For (b) consider: f = $(...h....)
69 -- where h is imported, and calls f via an hi-boot file.
70 -- This is bad! But it is not seen as a staging error, because h
71 -- is indeed imported. We don't want the type-checker to black-hole
72 -- when simplifying and compiling the splice!
74 -- Simple solution: discard any unfolding that mentions a variable
75 -- bound in this module (and hence not yet processed).
76 -- The discarding happens when forkM finds a type error.
78 %************************************************************************
80 %* tcImportDecl is the key function for "faulting in" *
83 %************************************************************************
85 The main idea is this. We are chugging along type-checking source code, and
86 find a reference to GHC.Base.map. We call tcLookupGlobal, which doesn't find
87 it in the EPS type envt. So it
89 2 gets the decl for GHC.Base.map
90 3 typechecks it via tcIfaceDecl
91 4 and adds it to the type env in the EPS
93 Note that DURING STEP 4, we may find that map's type mentions a type
96 Notice that for imported things we read the current version from the EPS
97 mutable variable. This is important in situations like
99 where the code that e1 expands to might import some defns that
100 also turn out to be needed by the code that e2 expands to.
103 tcImportDecl :: Name -> TcM TyThing
104 -- Entry point for *source-code* uses of importDecl
106 | Just thing <- wiredInNameTyThing_maybe name
107 = do { initIfaceTcRn (loadWiredInHomeIface name)
110 = do { traceIf (text "tcImportDecl" <+> ppr name)
111 ; mb_thing <- initIfaceTcRn (importDecl name)
113 Succeeded thing -> return thing
114 Failed err -> failWithTc err }
116 checkWiredInTyCon :: TyCon -> TcM ()
117 -- Ensure that the home module of the TyCon (and hence its instances)
118 -- are loaded. It might not be a wired-in tycon (see the calls in TcUnify),
119 -- in which case this is a no-op.
121 | not (isWiredInName tc_name)
124 = do { mod <- getModule
125 ; unless (mod == nameModule tc_name)
126 (initIfaceTcRn (loadWiredInHomeIface tc_name))
127 -- Don't look for (non-existent) Float.hi when
128 -- compiling Float.lhs, which mentions Float of course
129 -- A bit yukky to call initIfaceTcRn here
132 tc_name = tyConName tc
134 importDecl :: Name -> IfM lcl (MaybeErr Message TyThing)
135 -- Get the TyThing for this Name from an interface file
136 -- It's not a wired-in thing -- the caller caught that
138 = ASSERT( not (isWiredInName name) )
141 -- Load the interface, which should populate the PTE
142 ; mb_iface <- loadInterface nd_doc (nameModule name) ImportBySystem
144 Failed err_msg -> return (Failed err_msg) ;
145 Succeeded iface -> do
147 -- Now look it up again; this time we should find it
149 ; case lookupTypeEnv (eps_PTE eps) name of
150 Just thing -> return (Succeeded thing)
151 Nothing -> return (Failed not_found_msg)
154 nd_doc = ptext SLIT("Need decl for") <+> ppr name
155 not_found_msg = hang (ptext SLIT("Can't find interface-file declaration for") <+>
156 pprNameSpace (occNameSpace (nameOccName name)) <+> ppr name)
157 2 (vcat [ptext SLIT("Probable cause: bug in .hi-boot file, or inconsistent .hi file"),
158 ptext SLIT("Use -ddump-if-trace to get an idea of which file caused the error")])
161 %************************************************************************
163 Type-checking a complete interface
165 %************************************************************************
167 Suppose we discover we don't need to recompile. Then we must type
168 check the old interface file. This is a bit different to the
169 incremental type checking we do as we suck in interface files. Instead
170 we do things similarly as when we are typechecking source decls: we
171 bring into scope the type envt for the interface all at once, using a
172 knot. Remember, the decls aren't necessarily in dependency order --
173 and even if they were, the type decls might be mutually recursive.
176 typecheckIface :: ModIface -- Get the decls from here
177 -> TcRnIf gbl lcl ModDetails
179 = initIfaceTc iface $ \ tc_env_var -> do
180 -- The tc_env_var is freshly allocated, private to
181 -- type-checking this particular interface
182 { -- Get the right set of decls and rules. If we are compiling without -O
183 -- we discard pragmas before typechecking, so that we don't "see"
184 -- information that we shouldn't. From a versioning point of view
185 -- It's not actually *wrong* to do so, but in fact GHCi is unable
186 -- to handle unboxed tuples, so it must not see unfoldings.
187 ignore_prags <- doptM Opt_IgnoreInterfacePragmas
189 -- Typecheck the decls. This is done lazily, so that the knot-tying
190 -- within this single module work out right. In the If monad there is
191 -- no global envt for the current interface; instead, the knot is tied
192 -- through the if_rec_types field of IfGblEnv
193 ; names_w_things <- loadDecls ignore_prags (mi_decls iface)
194 ; let type_env = mkNameEnv names_w_things
195 ; writeMutVar tc_env_var type_env
197 -- Now do those rules and instances
198 ; insts <- mapM tcIfaceInst (mi_insts iface)
199 ; fam_insts <- mapM tcIfaceFamInst (mi_fam_insts iface)
200 ; rules <- tcIfaceRules ignore_prags (mi_rules iface)
203 ; exports <- ifaceExportNames (mi_exports iface)
206 ; traceIf (vcat [text "Finished typechecking interface for" <+> ppr (mi_module iface),
207 text "Type envt:" <+> ppr type_env])
208 ; return $ ModDetails { md_types = type_env
210 , md_fam_insts = fam_insts
212 , md_exports = exports
213 , md_modBreaks = emptyModBreaks
219 %************************************************************************
221 Type and class declarations
223 %************************************************************************
226 tcHiBootIface :: HscSource -> Module -> TcRn ModDetails
227 -- Load the hi-boot iface for the module being compiled,
228 -- if it indeed exists in the transitive closure of imports
229 -- Return the ModDetails, empty if no hi-boot iface
230 tcHiBootIface hsc_src mod
231 | isHsBoot hsc_src -- Already compiling a hs-boot file
232 = return emptyModDetails
234 = do { traceIf (text "loadHiBootInterface" <+> ppr mod)
237 ; if not (isOneShot mode)
238 -- In --make and interactive mode, if this module has an hs-boot file
239 -- we'll have compiled it already, and it'll be in the HPT
241 -- We check wheher the interface is a *boot* interface.
242 -- It can happen (when using GHC from Visual Studio) that we
243 -- compile a module in TypecheckOnly mode, with a stable,
244 -- fully-populated HPT. In that case the boot interface isn't there
245 -- (it's been replaced by the mother module) so we can't check it.
246 -- And that's fine, because if M's ModInfo is in the HPT, then
247 -- it's been compiled once, and we don't need to check the boot iface
248 then do { hpt <- getHpt
249 ; case lookupUFM hpt (moduleName mod) of
250 Just info | mi_boot (hm_iface info)
251 -> return (hm_details info)
252 other -> return emptyModDetails }
255 -- OK, so we're in one-shot mode.
256 -- In that case, we're read all the direct imports by now,
257 -- so eps_is_boot will record if any of our imports mention us by
258 -- way of hi-boot file
260 ; case lookupUFM (eps_is_boot eps) (moduleName mod) of {
261 Nothing -> return emptyModDetails ; -- The typical case
263 Just (_, False) -> failWithTc moduleLoop ;
264 -- Someone below us imported us!
265 -- This is a loop with no hi-boot in the way
267 Just (_mod, True) -> -- There's a hi-boot interface below us
269 do { read_result <- findAndReadIface
273 ; case read_result of
274 Failed err -> failWithTc (elaborate err)
275 Succeeded (iface, _path) -> typecheckIface iface
278 need = ptext SLIT("Need the hi-boot interface for") <+> ppr mod
279 <+> ptext SLIT("to compare against the Real Thing")
281 moduleLoop = ptext SLIT("Circular imports: module") <+> quotes (ppr mod)
282 <+> ptext SLIT("depends on itself")
284 elaborate err = hang (ptext SLIT("Could not find hi-boot interface for") <+>
285 quotes (ppr mod) <> colon) 4 err
289 %************************************************************************
291 Type and class declarations
293 %************************************************************************
295 When typechecking a data type decl, we *lazily* (via forkM) typecheck
296 the constructor argument types. This is in the hope that we may never
297 poke on those argument types, and hence may never need to load the
298 interface files for types mentioned in the arg types.
301 data Foo.S = MkS Baz.T
302 Mabye we can get away without even loading the interface for Baz!
304 This is not just a performance thing. Suppose we have
305 data Foo.S = MkS Baz.T
306 data Baz.T = MkT Foo.S
307 (in different interface files, of course).
308 Now, first we load and typecheck Foo.S, and add it to the type envt.
309 If we do explore MkS's argument, we'll load and typecheck Baz.T.
310 If we explore MkT's argument we'll find Foo.S already in the envt.
312 If we typechecked constructor args eagerly, when loading Foo.S we'd try to
313 typecheck the type Baz.T. So we'd fault in Baz.T... and then need Foo.S...
314 which isn't done yet.
316 All very cunning. However, there is a rather subtle gotcha which bit
317 me when developing this stuff. When we typecheck the decl for S, we
318 extend the type envt with S, MkS, and all its implicit Ids. Suppose
319 (a bug, but it happened) that the list of implicit Ids depended in
320 turn on the constructor arg types. Then the following sequence of
322 * we build a thunk <t> for the constructor arg tys
323 * we build a thunk for the extended type environment (depends on <t>)
324 * we write the extended type envt into the global EPS mutvar
326 Now we look something up in the type envt
328 * which reads the global type envt out of the global EPS mutvar
329 * but that depends in turn on <t>
331 It's subtle, because, it'd work fine if we typechecked the constructor args
332 eagerly -- they don't need the extended type envt. They just get the extended
333 type envt by accident, because they look at it later.
335 What this means is that the implicitTyThings MUST NOT DEPEND on any of
340 tcIfaceDecl :: Bool -- True <=> discard IdInfo on IfaceId bindings
344 tcIfaceDecl ignore_prags (IfaceId {ifName = occ_name, ifType = iface_type, ifIdInfo = info})
345 = do { name <- lookupIfaceTop occ_name
346 ; ty <- tcIfaceType iface_type
347 ; info <- tcIdInfo ignore_prags name ty info
348 ; return (AnId (mkVanillaGlobal name ty info)) }
350 tcIfaceDecl ignore_prags
351 (IfaceData {ifName = occ_name,
353 ifCtxt = ctxt, ifGadtSyntax = gadt_syn,
356 ifGeneric = want_generic,
357 ifFamInst = mb_family })
358 = do { tc_name <- lookupIfaceTop occ_name
359 ; bindIfaceTyVars tv_bndrs $ \ tyvars -> do
361 { tycon <- fixM ( \ tycon -> do
362 { stupid_theta <- tcIfaceCtxt ctxt
365 Nothing -> return Nothing
367 do { famTyCon <- tcIfaceTyCon fam
368 ; insttys <- mapM tcIfaceType tys
369 ; return $ Just (famTyCon, insttys)
371 ; cons <- tcIfaceDataCons tc_name tycon tyvars rdr_cons
372 ; buildAlgTyCon tc_name tyvars stupid_theta
373 cons is_rec want_generic gadt_syn famInst
375 ; traceIf (text "tcIfaceDecl4" <+> ppr tycon)
376 ; return (ATyCon tycon)
379 tcIfaceDecl ignore_prags
380 (IfaceSyn {ifName = occ_name, ifTyVars = tv_bndrs,
381 ifOpenSyn = isOpen, ifSynRhs = rdr_rhs_ty})
382 = bindIfaceTyVars tv_bndrs $ \ tyvars -> do
383 { tc_name <- lookupIfaceTop occ_name
384 ; rhs_tyki <- tcIfaceType rdr_rhs_ty
385 ; let rhs = if isOpen then OpenSynTyCon rhs_tyki Nothing
386 else SynonymTyCon rhs_tyki
387 ; return (ATyCon (buildSynTyCon tc_name tyvars rhs))
390 tcIfaceDecl ignore_prags
391 (IfaceClass {ifCtxt = rdr_ctxt, ifName = occ_name,
392 ifTyVars = tv_bndrs, ifFDs = rdr_fds,
393 ifATs = rdr_ats, ifSigs = rdr_sigs,
395 -- ToDo: in hs-boot files we should really treat abstract classes specially,
396 -- as we do abstract tycons
397 = bindIfaceTyVars tv_bndrs $ \ tyvars -> do
398 { cls_name <- lookupIfaceTop occ_name
399 ; ctxt <- tcIfaceCtxt rdr_ctxt
400 ; sigs <- mappM tc_sig rdr_sigs
401 ; fds <- mappM tc_fd rdr_fds
402 ; ats' <- mappM (tcIfaceDecl ignore_prags) rdr_ats
403 ; let ats = zipWith setTyThingPoss ats' (map ifTyVars rdr_ats)
404 ; cls <- buildClass cls_name tyvars ctxt fds ats sigs tc_isrec
405 ; return (AClass cls) }
407 tc_sig (IfaceClassOp occ dm rdr_ty)
408 = do { op_name <- lookupIfaceTop occ
409 ; op_ty <- forkM (mk_doc op_name rdr_ty) (tcIfaceType rdr_ty)
410 -- Must be done lazily for just the same reason as the
411 -- type of a data con; to avoid sucking in types that
412 -- it mentions unless it's necessray to do so
413 ; return (op_name, dm, op_ty) }
415 mk_doc op_name op_ty = ptext SLIT("Class op") <+> sep [ppr op_name, ppr op_ty]
417 tc_fd (tvs1, tvs2) = do { tvs1' <- mappM tcIfaceTyVar tvs1
418 ; tvs2' <- mappM tcIfaceTyVar tvs2
419 ; return (tvs1', tvs2') }
421 -- For each AT argument compute the position of the corresponding class
422 -- parameter in the class head. This will later serve as a permutation
423 -- vector when checking the validity of instance declarations.
424 setTyThingPoss (ATyCon tycon) atTyVars =
425 let classTyVars = map fst tv_bndrs
427 . map ((`elemIndex` classTyVars) . fst)
429 -- There will be no Nothing, as we already passed renaming
431 ATyCon (setTyConArgPoss tycon poss)
432 setTyThingPoss _ _ = panic "TcIface.setTyThingPoss"
434 tcIfaceDecl ignore_prags (IfaceForeign {ifName = rdr_name, ifExtName = ext_name})
435 = do { name <- lookupIfaceTop rdr_name
436 ; return (ATyCon (mkForeignTyCon name ext_name
439 tcIfaceDataCons tycon_name tycon tc_tyvars if_cons
441 IfAbstractTyCon -> return mkAbstractTyConRhs
442 IfOpenDataTyCon -> return mkOpenDataTyConRhs
443 IfOpenNewTyCon -> return mkOpenNewTyConRhs
444 IfDataTyCon cons -> do { data_cons <- mappM tc_con_decl cons
445 ; return (mkDataTyConRhs data_cons) }
446 IfNewTyCon con -> do { data_con <- tc_con_decl con
447 ; mkNewTyConRhs tycon_name tycon data_con }
449 tc_con_decl (IfCon { ifConInfix = is_infix,
450 ifConUnivTvs = univ_tvs, ifConExTvs = ex_tvs,
451 ifConOcc = occ, ifConCtxt = ctxt, ifConEqSpec = spec,
452 ifConArgTys = args, ifConFields = field_lbls,
453 ifConStricts = stricts})
454 = bindIfaceTyVars univ_tvs $ \ univ_tyvars -> do
455 bindIfaceTyVars ex_tvs $ \ ex_tyvars -> do
456 { name <- lookupIfaceTop occ
457 ; eq_spec <- tcIfaceEqSpec spec
458 ; theta <- tcIfaceCtxt ctxt -- Laziness seems not worth the bother here
459 -- At one stage I thought that this context checking *had*
460 -- to be lazy, because of possible mutual recursion between the
461 -- type and the classe:
463 -- class Real a where { toRat :: a -> Ratio Integer }
464 -- data (Real a) => Ratio a = ...
465 -- But now I think that the laziness in checking class ops breaks
466 -- the loop, so no laziness needed
468 -- Read the argument types, but lazily to avoid faulting in
469 -- the component types unless they are really needed
470 ; arg_tys <- forkM (mk_doc name) (mappM tcIfaceType args)
471 ; lbl_names <- mappM lookupIfaceTop field_lbls
473 ; buildDataCon name is_infix {- Not infix -}
475 univ_tyvars ex_tyvars
479 mk_doc con_name = ptext SLIT("Constructor") <+> ppr con_name
484 do_item (occ, if_ty) = do { tv <- tcIfaceTyVar (occNameFS occ)
485 ; ty <- tcIfaceType if_ty
490 %************************************************************************
494 %************************************************************************
497 tcIfaceInst :: IfaceInst -> IfL Instance
498 tcIfaceInst (IfaceInst { ifDFun = dfun_occ, ifOFlag = oflag,
499 ifInstCls = cls, ifInstTys = mb_tcs,
501 = do { dfun <- forkM (ptext SLIT("Dict fun") <+> ppr dfun_occ) $
502 tcIfaceExtId dfun_occ
503 ; let mb_tcs' = map (fmap ifaceTyConName) mb_tcs
504 ; return (mkImportedInstance cls mb_tcs' dfun oflag) }
506 tcIfaceFamInst :: IfaceFamInst -> IfL FamInst
507 tcIfaceFamInst (IfaceFamInst { ifFamInstTyCon = tycon,
508 ifFamInstFam = fam, ifFamInstTys = mb_tcs })
509 -- = do { tycon' <- forkM (ptext SLIT("Inst tycon") <+> ppr tycon) $
510 -- ^^^this line doesn't work, but vvv this does => CPP in Haskell = evil!
511 = do { tycon' <- forkM (text ("Inst tycon") <+> ppr tycon) $
513 ; let mb_tcs' = map (fmap ifaceTyConName) mb_tcs
514 ; return (mkImportedFamInst fam mb_tcs' tycon') }
518 %************************************************************************
522 %************************************************************************
524 We move a IfaceRule from eps_rules to eps_rule_base when all its LHS free vars
525 are in the type environment. However, remember that typechecking a Rule may
526 (as a side effect) augment the type envt, and so we may need to iterate the process.
529 tcIfaceRules :: Bool -- True <=> ignore rules
532 tcIfaceRules ignore_prags if_rules
533 | ignore_prags = return []
534 | otherwise = mapM tcIfaceRule if_rules
536 tcIfaceRule :: IfaceRule -> IfL CoreRule
537 tcIfaceRule (IfaceRule {ifRuleName = name, ifActivation = act, ifRuleBndrs = bndrs,
538 ifRuleHead = fn, ifRuleArgs = args, ifRuleRhs = rhs,
540 = do { ~(bndrs', args', rhs') <-
541 -- Typecheck the payload lazily, in the hope it'll never be looked at
542 forkM (ptext SLIT("Rule") <+> ftext name) $
543 bindIfaceBndrs bndrs $ \ bndrs' ->
544 do { args' <- mappM tcIfaceExpr args
545 ; rhs' <- tcIfaceExpr rhs
546 ; return (bndrs', args', rhs') }
547 ; let mb_tcs = map ifTopFreeName args
549 ; returnM (Rule { ru_name = name, ru_fn = fn, ru_act = act,
550 ru_bndrs = bndrs', ru_args = args',
553 ru_local = False }) } -- An imported RULE is never for a local Id
554 -- or, even if it is (module loop, perhaps)
555 -- we'll just leave it in the non-local set
557 -- This function *must* mirror exactly what Rules.topFreeName does
558 -- We could have stored the ru_rough field in the iface file
559 -- but that would be redundant, I think.
560 -- The only wrinkle is that we must not be deceived by
561 -- type syononyms at the top of a type arg. Since
562 -- we can't tell at this point, we are careful not
563 -- to write them out in coreRuleToIfaceRule
564 ifTopFreeName :: IfaceExpr -> Maybe Name
565 ifTopFreeName (IfaceType (IfaceTyConApp tc _ )) = Just (ifaceTyConName tc)
566 ifTopFreeName (IfaceApp f a) = ifTopFreeName f
567 ifTopFreeName (IfaceExt n) = Just n
568 ifTopFreeName other = Nothing
572 %************************************************************************
576 %************************************************************************
579 tcIfaceType :: IfaceType -> IfL Type
580 tcIfaceType (IfaceTyVar n) = do { tv <- tcIfaceTyVar n; return (TyVarTy tv) }
581 tcIfaceType (IfaceAppTy t1 t2) = do { t1' <- tcIfaceType t1; t2' <- tcIfaceType t2; return (AppTy t1' t2') }
582 tcIfaceType (IfaceFunTy t1 t2) = do { t1' <- tcIfaceType t1; t2' <- tcIfaceType t2; return (FunTy t1' t2') }
583 tcIfaceType (IfaceTyConApp tc ts) = do { tc' <- tcIfaceTyCon tc; ts' <- tcIfaceTypes ts; return (mkTyConApp tc' ts') }
584 tcIfaceType (IfaceForAllTy tv t) = bindIfaceTyVar tv $ \ tv' -> do { t' <- tcIfaceType t; return (ForAllTy tv' t') }
585 tcIfaceType (IfacePredTy st) = do { st' <- tcIfacePredType st; return (PredTy st') }
587 tcIfaceTypes tys = mapM tcIfaceType tys
589 -----------------------------------------
590 tcIfacePredType :: IfacePredType -> IfL PredType
591 tcIfacePredType (IfaceClassP cls ts) = do { cls' <- tcIfaceClass cls; ts' <- tcIfaceTypes ts; return (ClassP cls' ts') }
592 tcIfacePredType (IfaceIParam ip t) = do { ip' <- newIPName ip; t' <- tcIfaceType t; return (IParam ip' t') }
593 tcIfacePredType (IfaceEqPred t1 t2) = do { t1' <- tcIfaceType t1; t2' <- tcIfaceType t2; return (EqPred t1' t2') }
595 -----------------------------------------
596 tcIfaceCtxt :: IfaceContext -> IfL ThetaType
597 tcIfaceCtxt sts = mappM tcIfacePredType sts
601 %************************************************************************
605 %************************************************************************
608 tcIfaceExpr :: IfaceExpr -> IfL CoreExpr
609 tcIfaceExpr (IfaceType ty)
610 = tcIfaceType ty `thenM` \ ty' ->
613 tcIfaceExpr (IfaceLcl name)
614 = tcIfaceLclId name `thenM` \ id ->
617 tcIfaceExpr (IfaceExt gbl)
618 = tcIfaceExtId gbl `thenM` \ id ->
621 tcIfaceExpr (IfaceLit lit)
624 tcIfaceExpr (IfaceFCall cc ty)
625 = tcIfaceType ty `thenM` \ ty' ->
626 newUnique `thenM` \ u ->
627 returnM (Var (mkFCallId u cc ty'))
629 tcIfaceExpr (IfaceTuple boxity args)
630 = mappM tcIfaceExpr args `thenM` \ args' ->
632 -- Put the missing type arguments back in
633 con_args = map (Type . exprType) args' ++ args'
635 returnM (mkApps (Var con_id) con_args)
638 con_id = dataConWorkId (tupleCon boxity arity)
641 tcIfaceExpr (IfaceLam bndr body)
642 = bindIfaceBndr bndr $ \ bndr' ->
643 tcIfaceExpr body `thenM` \ body' ->
644 returnM (Lam bndr' body')
646 tcIfaceExpr (IfaceApp fun arg)
647 = tcIfaceExpr fun `thenM` \ fun' ->
648 tcIfaceExpr arg `thenM` \ arg' ->
649 returnM (App fun' arg')
651 tcIfaceExpr (IfaceCase scrut case_bndr ty alts)
652 = tcIfaceExpr scrut `thenM` \ scrut' ->
653 newIfaceName (mkVarOccFS case_bndr) `thenM` \ case_bndr_name ->
655 scrut_ty = exprType scrut'
656 case_bndr' = mkLocalId case_bndr_name scrut_ty
657 tc_app = splitTyConApp scrut_ty
658 -- NB: Won't always succeed (polymoprhic case)
659 -- but won't be demanded in those cases
660 -- NB: not tcSplitTyConApp; we are looking at Core here
661 -- look through non-rec newtypes to find the tycon that
662 -- corresponds to the datacon in this case alternative
664 extendIfaceIdEnv [case_bndr'] $
665 mappM (tcIfaceAlt tc_app) alts `thenM` \ alts' ->
666 tcIfaceType ty `thenM` \ ty' ->
667 returnM (Case scrut' case_bndr' ty' alts')
669 tcIfaceExpr (IfaceLet (IfaceNonRec bndr rhs) body)
670 = tcIfaceExpr rhs `thenM` \ rhs' ->
671 bindIfaceId bndr $ \ bndr' ->
672 tcIfaceExpr body `thenM` \ body' ->
673 returnM (Let (NonRec bndr' rhs') body')
675 tcIfaceExpr (IfaceLet (IfaceRec pairs) body)
676 = bindIfaceIds bndrs $ \ bndrs' ->
677 mappM tcIfaceExpr rhss `thenM` \ rhss' ->
678 tcIfaceExpr body `thenM` \ body' ->
679 returnM (Let (Rec (bndrs' `zip` rhss')) body')
681 (bndrs, rhss) = unzip pairs
683 tcIfaceExpr (IfaceCast expr co) = do
684 expr' <- tcIfaceExpr expr
685 co' <- tcIfaceType co
686 returnM (Cast expr' co')
688 tcIfaceExpr (IfaceNote note expr)
689 = tcIfaceExpr expr `thenM` \ expr' ->
691 IfaceInlineMe -> returnM (Note InlineMe expr')
692 IfaceSCC cc -> returnM (Note (SCC cc) expr')
693 IfaceCoreNote n -> returnM (Note (CoreNote n) expr')
695 -------------------------
696 tcIfaceAlt _ (IfaceDefault, names, rhs)
697 = ASSERT( null names )
698 tcIfaceExpr rhs `thenM` \ rhs' ->
699 returnM (DEFAULT, [], rhs')
701 tcIfaceAlt _ (IfaceLitAlt lit, names, rhs)
702 = ASSERT( null names )
703 tcIfaceExpr rhs `thenM` \ rhs' ->
704 returnM (LitAlt lit, [], rhs')
706 -- A case alternative is made quite a bit more complicated
707 -- by the fact that we omit type annotations because we can
708 -- work them out. True enough, but its not that easy!
709 tcIfaceAlt (tycon, inst_tys) (IfaceDataAlt data_occ, arg_strs, rhs)
710 = do { con <- tcIfaceDataCon data_occ
711 ; ASSERT2( con `elem` tyConDataCons tycon,
712 ppr con $$ ppr tycon $$ ppr (tyConDataCons tycon) )
713 tcIfaceDataAlt con inst_tys arg_strs rhs }
715 tcIfaceAlt (tycon, inst_tys) (IfaceTupleAlt boxity, arg_occs, rhs)
716 = ASSERT( isTupleTyCon tycon )
717 do { let [data_con] = tyConDataCons tycon
718 ; tcIfaceDataAlt data_con inst_tys arg_occs rhs }
720 tcIfaceDataAlt con inst_tys arg_strs rhs
721 = do { us <- newUniqueSupply
722 ; let uniqs = uniqsFromSupply us
723 ; let (ex_tvs, co_tvs, arg_ids)
724 = dataConRepFSInstPat arg_strs uniqs con inst_tys
725 all_tvs = ex_tvs ++ co_tvs
727 ; rhs' <- extendIfaceTyVarEnv all_tvs $
728 extendIfaceIdEnv arg_ids $
730 ; return (DataAlt con, all_tvs ++ arg_ids, rhs') }
735 tcExtCoreBindings :: [IfaceBinding] -> IfL [CoreBind] -- Used for external core
736 tcExtCoreBindings [] = return []
737 tcExtCoreBindings (b:bs) = do_one b (tcExtCoreBindings bs)
739 do_one :: IfaceBinding -> IfL [CoreBind] -> IfL [CoreBind]
740 do_one (IfaceNonRec bndr rhs) thing_inside
741 = do { rhs' <- tcIfaceExpr rhs
742 ; bndr' <- newExtCoreBndr bndr
743 ; extendIfaceIdEnv [bndr'] $ do
744 { core_binds <- thing_inside
745 ; return (NonRec bndr' rhs' : core_binds) }}
747 do_one (IfaceRec pairs) thing_inside
748 = do { bndrs' <- mappM newExtCoreBndr bndrs
749 ; extendIfaceIdEnv bndrs' $ do
750 { rhss' <- mappM tcIfaceExpr rhss
751 ; core_binds <- thing_inside
752 ; return (Rec (bndrs' `zip` rhss') : core_binds) }}
754 (bndrs,rhss) = unzip pairs
758 %************************************************************************
762 %************************************************************************
765 tcIdInfo :: Bool -> Name -> Type -> IfaceIdInfo -> IfL IdInfo
766 tcIdInfo ignore_prags name ty info
767 | ignore_prags = return vanillaIdInfo
768 | otherwise = case info of
769 NoInfo -> return vanillaIdInfo
770 HasInfo info -> foldlM tcPrag init_info info
772 -- Set the CgInfo to something sensible but uninformative before
773 -- we start; default assumption is that it has CAFs
774 init_info = vanillaIdInfo
776 tcPrag info HsNoCafRefs = returnM (info `setCafInfo` NoCafRefs)
777 tcPrag info (HsArity arity) = returnM (info `setArityInfo` arity)
778 tcPrag info (HsStrictness str) = returnM (info `setAllStrictnessInfo` Just str)
780 -- The next two are lazy, so they don't transitively suck stuff in
781 tcPrag info (HsWorker nm arity) = tcWorkerInfo ty info nm arity
782 tcPrag info (HsInline inline_prag) = returnM (info `setInlinePragInfo` inline_prag)
783 tcPrag info (HsUnfold expr)
784 = tcPragExpr name expr `thenM` \ maybe_expr' ->
786 -- maybe_expr' doesn't get looked at if the unfolding
787 -- is never inspected; so the typecheck doesn't even happen
788 unfold_info = case maybe_expr' of
789 Nothing -> noUnfolding
790 Just expr' -> mkTopUnfolding expr'
792 returnM (info `setUnfoldingInfoLazily` unfold_info)
796 tcWorkerInfo ty info wkr arity
797 = do { mb_wkr_id <- forkM_maybe doc (tcIfaceExtId wkr)
799 -- We return without testing maybe_wkr_id, but as soon as info is
800 -- looked at we will test it. That's ok, because its outside the
801 -- knot; and there seems no big reason to further defer the
802 -- tcIfaceId lookup. (Contrast with tcPragExpr, where postponing walking
803 -- over the unfolding until it's actually used does seem worth while.)
804 ; us <- newUniqueSupply
806 ; returnM (case mb_wkr_id of
808 Just wkr_id -> add_wkr_info us wkr_id info) }
810 doc = text "Worker for" <+> ppr wkr
811 add_wkr_info us wkr_id info
812 = info `setUnfoldingInfoLazily` mk_unfolding us wkr_id
813 `setWorkerInfo` HasWorker wkr_id arity
815 mk_unfolding us wkr_id = mkTopUnfolding (initUs_ us (mkWrapper ty strict_sig) wkr_id)
817 -- We are relying here on strictness info always appearing
818 -- before worker info, fingers crossed ....
819 strict_sig = case newStrictnessInfo info of
821 Nothing -> pprPanic "Worker info but no strictness for" (ppr wkr)
824 For unfoldings we try to do the job lazily, so that we never type check
825 an unfolding that isn't going to be looked at.
828 tcPragExpr :: Name -> IfaceExpr -> IfL (Maybe CoreExpr)
831 tcIfaceExpr expr `thenM` \ core_expr' ->
833 -- Check for type consistency in the unfolding
834 ifOptM Opt_DoCoreLinting (
835 get_in_scope_ids `thenM` \ in_scope ->
836 case lintUnfolding noSrcLoc in_scope core_expr' of
837 Nothing -> returnM ()
838 Just fail_msg -> pprPanic "Iface Lint failure" (hang doc 2 fail_msg)
843 doc = text "Unfolding of" <+> ppr name
844 get_in_scope_ids -- Urgh; but just for linting
846 do { env <- getGblEnv
847 ; case if_rec_types env of {
848 Nothing -> return [] ;
849 Just (_, get_env) -> do
850 { type_env <- get_env
851 ; return (typeEnvIds type_env) }}}
856 %************************************************************************
858 Getting from Names to TyThings
860 %************************************************************************
863 tcIfaceGlobal :: Name -> IfL TyThing
865 | Just thing <- wiredInNameTyThing_maybe name
866 -- Wired-in things include TyCons, DataCons, and Ids
867 = do { ifCheckWiredInThing name; return thing }
869 = do { (eps,hpt) <- getEpsAndHpt
871 ; case lookupType dflags hpt (eps_PTE eps) name of {
872 Just thing -> return thing ;
876 ; case if_rec_types env of {
877 Just (mod, get_type_env)
878 | nameIsLocalOrFrom mod name
879 -> do -- It's defined in the module being compiled
880 { type_env <- setLclEnv () get_type_env -- yuk
881 ; case lookupNameEnv type_env name of
882 Just thing -> return thing
883 Nothing -> pprPanic "tcIfaceGlobal (local): not found:"
884 (ppr name $$ ppr type_env) }
888 { mb_thing <- importDecl name -- It's imported; go get it
890 Failed err -> failIfM err
891 Succeeded thing -> return thing
894 ifCheckWiredInThing :: Name -> IfL ()
895 -- Even though we are in an interface file, we want to make
896 -- sure the instances of a wired-in thing are loaded (imagine f :: Double -> Double)
897 -- Ditto want to ensure that RULES are loaded too
898 ifCheckWiredInThing name
899 = do { mod <- getIfModule
900 -- Check whether we are typechecking the interface for this
901 -- very module. E.g when compiling the base library in --make mode
902 -- we may typecheck GHC.Base.hi. At that point, GHC.Base is not in
903 -- the HPT, so without the test we'll demand-load it into the PIT!
904 -- C.f. the same test in checkWiredInTyCon above
905 ; unless (mod == nameModule name)
906 (loadWiredInHomeIface name) }
908 tcIfaceTyCon :: IfaceTyCon -> IfL TyCon
909 tcIfaceTyCon IfaceIntTc = tcWiredInTyCon intTyCon
910 tcIfaceTyCon IfaceBoolTc = tcWiredInTyCon boolTyCon
911 tcIfaceTyCon IfaceCharTc = tcWiredInTyCon charTyCon
912 tcIfaceTyCon IfaceListTc = tcWiredInTyCon listTyCon
913 tcIfaceTyCon IfacePArrTc = tcWiredInTyCon parrTyCon
914 tcIfaceTyCon (IfaceTupTc bx ar) = tcWiredInTyCon (tupleTyCon bx ar)
915 tcIfaceTyCon (IfaceTc name) = do { thing <- tcIfaceGlobal name
916 ; return (check_tc (tyThingTyCon thing)) }
919 check_tc tc = case toIfaceTyCon tc of
921 other -> pprTrace "check_tc" (ppr tc) tc
925 -- we should be okay just returning Kind constructors without extra loading
926 tcIfaceTyCon IfaceLiftedTypeKindTc = return liftedTypeKindTyCon
927 tcIfaceTyCon IfaceOpenTypeKindTc = return openTypeKindTyCon
928 tcIfaceTyCon IfaceUnliftedTypeKindTc = return unliftedTypeKindTyCon
929 tcIfaceTyCon IfaceArgTypeKindTc = return argTypeKindTyCon
930 tcIfaceTyCon IfaceUbxTupleKindTc = return ubxTupleKindTyCon
932 -- Even though we are in an interface file, we want to make
933 -- sure the instances and RULES of this tycon are loaded
934 -- Imagine: f :: Double -> Double
935 tcWiredInTyCon :: TyCon -> IfL TyCon
936 tcWiredInTyCon tc = do { ifCheckWiredInThing (tyConName tc)
939 tcIfaceClass :: Name -> IfL Class
940 tcIfaceClass name = do { thing <- tcIfaceGlobal name
941 ; return (tyThingClass thing) }
943 tcIfaceDataCon :: Name -> IfL DataCon
944 tcIfaceDataCon name = do { thing <- tcIfaceGlobal name
946 ADataCon dc -> return dc
947 other -> pprPanic "tcIfaceExtDC" (ppr name$$ ppr thing) }
949 tcIfaceExtId :: Name -> IfL Id
950 tcIfaceExtId name = do { thing <- tcIfaceGlobal name
953 other -> pprPanic "tcIfaceExtId" (ppr name$$ ppr thing) }
956 %************************************************************************
960 %************************************************************************
963 bindIfaceBndr :: IfaceBndr -> (CoreBndr -> IfL a) -> IfL a
964 bindIfaceBndr (IfaceIdBndr bndr) thing_inside
965 = bindIfaceId bndr thing_inside
966 bindIfaceBndr (IfaceTvBndr bndr) thing_inside
967 = bindIfaceTyVar bndr thing_inside
969 bindIfaceBndrs :: [IfaceBndr] -> ([CoreBndr] -> IfL a) -> IfL a
970 bindIfaceBndrs [] thing_inside = thing_inside []
971 bindIfaceBndrs (b:bs) thing_inside
972 = bindIfaceBndr b $ \ b' ->
973 bindIfaceBndrs bs $ \ bs' ->
974 thing_inside (b':bs')
976 -----------------------
977 bindIfaceId :: IfaceIdBndr -> (Id -> IfL a) -> IfL a
978 bindIfaceId (occ, ty) thing_inside
979 = do { name <- newIfaceName (mkVarOccFS occ)
980 ; ty' <- tcIfaceType ty
981 ; let { id = mkLocalId name ty' }
982 ; extendIfaceIdEnv [id] (thing_inside id) }
984 bindIfaceIds :: [IfaceIdBndr] -> ([Id] -> IfL a) -> IfL a
985 bindIfaceIds bndrs thing_inside
986 = do { names <- newIfaceNames (map mkVarOccFS occs)
987 ; tys' <- mappM tcIfaceType tys
988 ; let { ids = zipWithEqual "tcCoreValBndr" mkLocalId names tys' }
989 ; extendIfaceIdEnv ids (thing_inside ids) }
991 (occs,tys) = unzip bndrs
994 -----------------------
995 newExtCoreBndr :: IfaceIdBndr -> IfL Id
996 newExtCoreBndr (var, ty)
997 = do { mod <- getIfModule
998 ; name <- newGlobalBinder mod (mkVarOccFS var) noSrcLoc
999 ; ty' <- tcIfaceType ty
1000 ; return (mkLocalId name ty') }
1002 -----------------------
1003 bindIfaceTyVar :: IfaceTvBndr -> (TyVar -> IfL a) -> IfL a
1004 bindIfaceTyVar (occ,kind) thing_inside
1005 = do { name <- newIfaceName (mkTyVarOcc occ)
1006 ; tyvar <- mk_iface_tyvar name kind
1007 ; extendIfaceTyVarEnv [tyvar] (thing_inside tyvar) }
1009 bindIfaceTyVars :: [IfaceTvBndr] -> ([TyVar] -> IfL a) -> IfL a
1010 bindIfaceTyVars bndrs thing_inside
1011 = do { names <- newIfaceNames (map mkTyVarOcc occs)
1012 ; tyvars <- TcRnMonad.zipWithM mk_iface_tyvar names kinds
1013 ; extendIfaceTyVarEnv tyvars (thing_inside tyvars) }
1015 (occs,kinds) = unzip bndrs
1017 mk_iface_tyvar :: Name -> IfaceKind -> IfL TyVar
1018 mk_iface_tyvar name ifKind
1019 = do { kind <- tcIfaceType ifKind
1020 ; if isCoercionKind kind then
1021 return (Var.mkCoVar name kind)
1023 return (Var.mkTyVar name kind) }