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"
64 An IfaceDecl is populated with RdrNames, and these are not renamed to
65 Names before typechecking, because there should be no scope errors etc.
67 -- For (b) consider: f = $(...h....)
68 -- where h is imported, and calls f via an hi-boot file.
69 -- This is bad! But it is not seen as a staging error, because h
70 -- is indeed imported. We don't want the type-checker to black-hole
71 -- when simplifying and compiling the splice!
73 -- Simple solution: discard any unfolding that mentions a variable
74 -- bound in this module (and hence not yet processed).
75 -- The discarding happens when forkM finds a type error.
77 %************************************************************************
79 %* tcImportDecl is the key function for "faulting in" *
82 %************************************************************************
84 The main idea is this. We are chugging along type-checking source code, and
85 find a reference to GHC.Base.map. We call tcLookupGlobal, which doesn't find
86 it in the EPS type envt. So it
88 2 gets the decl for GHC.Base.map
89 3 typechecks it via tcIfaceDecl
90 4 and adds it to the type env in the EPS
92 Note that DURING STEP 4, we may find that map's type mentions a type
95 Notice that for imported things we read the current version from the EPS
96 mutable variable. This is important in situations like
98 where the code that e1 expands to might import some defns that
99 also turn out to be needed by the code that e2 expands to.
102 tcImportDecl :: Name -> TcM TyThing
103 -- Entry point for *source-code* uses of importDecl
105 | Just thing <- wiredInNameTyThing_maybe name
106 = do { initIfaceTcRn (loadWiredInHomeIface name)
109 = do { traceIf (text "tcImportDecl" <+> ppr name)
110 ; mb_thing <- initIfaceTcRn (importDecl name)
112 Succeeded thing -> return thing
113 Failed err -> failWithTc err }
115 checkWiredInTyCon :: TyCon -> TcM ()
116 -- Ensure that the home module of the TyCon (and hence its instances)
117 -- are loaded. It might not be a wired-in tycon (see the calls in TcUnify),
118 -- in which case this is a no-op.
120 | not (isWiredInName tc_name)
123 = do { mod <- getModule
124 ; unless (mod == nameModule tc_name)
125 (initIfaceTcRn (loadWiredInHomeIface tc_name))
126 -- Don't look for (non-existent) Float.hi when
127 -- compiling Float.lhs, which mentions Float of course
128 -- A bit yukky to call initIfaceTcRn here
131 tc_name = tyConName tc
133 importDecl :: Name -> IfM lcl (MaybeErr Message TyThing)
134 -- Get the TyThing for this Name from an interface file
135 -- It's not a wired-in thing -- the caller caught that
137 = ASSERT( not (isWiredInName name) )
140 -- Load the interface, which should populate the PTE
141 ; mb_iface <- loadInterface nd_doc (nameModule name) ImportBySystem
143 Failed err_msg -> return (Failed err_msg) ;
144 Succeeded iface -> do
146 -- Now look it up again; this time we should find it
148 ; case lookupTypeEnv (eps_PTE eps) name of
149 Just thing -> return (Succeeded thing)
150 Nothing -> return (Failed not_found_msg)
153 nd_doc = ptext SLIT("Need decl for") <+> ppr name
154 not_found_msg = hang (ptext SLIT("Can't find interface-file declaration for") <+>
155 pprNameSpace (occNameSpace (nameOccName name)) <+> ppr name)
156 2 (vcat [ptext SLIT("Probable cause: bug in .hi-boot file, or inconsistent .hi file"),
157 ptext SLIT("Use -ddump-if-trace to get an idea of which file caused the error")])
160 %************************************************************************
162 Type-checking a complete interface
164 %************************************************************************
166 Suppose we discover we don't need to recompile. Then we must type
167 check the old interface file. This is a bit different to the
168 incremental type checking we do as we suck in interface files. Instead
169 we do things similarly as when we are typechecking source decls: we
170 bring into scope the type envt for the interface all at once, using a
171 knot. Remember, the decls aren't necessarily in dependency order --
172 and even if they were, the type decls might be mutually recursive.
175 typecheckIface :: ModIface -- Get the decls from here
176 -> TcRnIf gbl lcl ModDetails
178 = initIfaceTc iface $ \ tc_env_var -> do
179 -- The tc_env_var is freshly allocated, private to
180 -- type-checking this particular interface
181 { -- Get the right set of decls and rules. If we are compiling without -O
182 -- we discard pragmas before typechecking, so that we don't "see"
183 -- information that we shouldn't. From a versioning point of view
184 -- It's not actually *wrong* to do so, but in fact GHCi is unable
185 -- to handle unboxed tuples, so it must not see unfoldings.
186 ignore_prags <- doptM Opt_IgnoreInterfacePragmas
188 -- Typecheck the decls. This is done lazily, so that the knot-tying
189 -- within this single module work out right. In the If monad there is
190 -- no global envt for the current interface; instead, the knot is tied
191 -- through the if_rec_types field of IfGblEnv
192 ; names_w_things <- loadDecls ignore_prags (mi_decls iface)
193 ; let type_env = mkNameEnv names_w_things
194 ; writeMutVar tc_env_var type_env
196 -- Now do those rules and instances
197 ; insts <- mapM tcIfaceInst (mi_insts iface)
198 ; fam_insts <- mapM tcIfaceFamInst (mi_fam_insts iface)
199 ; rules <- tcIfaceRules ignore_prags (mi_rules iface)
202 ; exports <- ifaceExportNames (mi_exports iface)
205 ; traceIf (vcat [text "Finished typechecking interface for" <+> ppr (mi_module iface),
206 text "Type envt:" <+> ppr type_env])
207 ; return $ ModDetails { md_types = type_env
209 , md_fam_insts = fam_insts
211 , md_exports = exports
212 , md_modBreaks = emptyModBreaks
218 %************************************************************************
220 Type and class declarations
222 %************************************************************************
225 tcHiBootIface :: HscSource -> Module -> TcRn ModDetails
226 -- Load the hi-boot iface for the module being compiled,
227 -- if it indeed exists in the transitive closure of imports
228 -- Return the ModDetails, empty if no hi-boot iface
229 tcHiBootIface hsc_src mod
230 | isHsBoot hsc_src -- Already compiling a hs-boot file
231 = return emptyModDetails
233 = do { traceIf (text "loadHiBootInterface" <+> ppr mod)
236 ; if not (isOneShot mode)
237 -- In --make and interactive mode, if this module has an hs-boot file
238 -- we'll have compiled it already, and it'll be in the HPT
240 -- We check wheher the interface is a *boot* interface.
241 -- It can happen (when using GHC from Visual Studio) that we
242 -- compile a module in TypecheckOnly mode, with a stable,
243 -- fully-populated HPT. In that case the boot interface isn't there
244 -- (it's been replaced by the mother module) so we can't check it.
245 -- And that's fine, because if M's ModInfo is in the HPT, then
246 -- it's been compiled once, and we don't need to check the boot iface
247 then do { hpt <- getHpt
248 ; case lookupUFM hpt (moduleName mod) of
249 Just info | mi_boot (hm_iface info)
250 -> return (hm_details info)
251 other -> return emptyModDetails }
254 -- OK, so we're in one-shot mode.
255 -- In that case, we're read all the direct imports by now,
256 -- so eps_is_boot will record if any of our imports mention us by
257 -- way of hi-boot file
259 ; case lookupUFM (eps_is_boot eps) (moduleName mod) of {
260 Nothing -> return emptyModDetails ; -- The typical case
262 Just (_, False) -> failWithTc moduleLoop ;
263 -- Someone below us imported us!
264 -- This is a loop with no hi-boot in the way
266 Just (_mod, True) -> -- There's a hi-boot interface below us
268 do { read_result <- findAndReadIface
272 ; case read_result of
273 Failed err -> failWithTc (elaborate err)
274 Succeeded (iface, _path) -> typecheckIface iface
277 need = ptext SLIT("Need the hi-boot interface for") <+> ppr mod
278 <+> ptext SLIT("to compare against the Real Thing")
280 moduleLoop = ptext SLIT("Circular imports: module") <+> quotes (ppr mod)
281 <+> ptext SLIT("depends on itself")
283 elaborate err = hang (ptext SLIT("Could not find hi-boot interface for") <+>
284 quotes (ppr mod) <> colon) 4 err
288 %************************************************************************
290 Type and class declarations
292 %************************************************************************
294 When typechecking a data type decl, we *lazily* (via forkM) typecheck
295 the constructor argument types. This is in the hope that we may never
296 poke on those argument types, and hence may never need to load the
297 interface files for types mentioned in the arg types.
300 data Foo.S = MkS Baz.T
301 Mabye we can get away without even loading the interface for Baz!
303 This is not just a performance thing. Suppose we have
304 data Foo.S = MkS Baz.T
305 data Baz.T = MkT Foo.S
306 (in different interface files, of course).
307 Now, first we load and typecheck Foo.S, and add it to the type envt.
308 If we do explore MkS's argument, we'll load and typecheck Baz.T.
309 If we explore MkT's argument we'll find Foo.S already in the envt.
311 If we typechecked constructor args eagerly, when loading Foo.S we'd try to
312 typecheck the type Baz.T. So we'd fault in Baz.T... and then need Foo.S...
313 which isn't done yet.
315 All very cunning. However, there is a rather subtle gotcha which bit
316 me when developing this stuff. When we typecheck the decl for S, we
317 extend the type envt with S, MkS, and all its implicit Ids. Suppose
318 (a bug, but it happened) that the list of implicit Ids depended in
319 turn on the constructor arg types. Then the following sequence of
321 * we build a thunk <t> for the constructor arg tys
322 * we build a thunk for the extended type environment (depends on <t>)
323 * we write the extended type envt into the global EPS mutvar
325 Now we look something up in the type envt
327 * which reads the global type envt out of the global EPS mutvar
328 * but that depends in turn on <t>
330 It's subtle, because, it'd work fine if we typechecked the constructor args
331 eagerly -- they don't need the extended type envt. They just get the extended
332 type envt by accident, because they look at it later.
334 What this means is that the implicitTyThings MUST NOT DEPEND on any of
339 tcIfaceDecl :: Bool -- True <=> discard IdInfo on IfaceId bindings
343 tcIfaceDecl ignore_prags (IfaceId {ifName = occ_name, ifType = iface_type, ifIdInfo = info})
344 = do { name <- lookupIfaceTop occ_name
345 ; ty <- tcIfaceType iface_type
346 ; info <- tcIdInfo ignore_prags name ty info
347 ; return (AnId (mkVanillaGlobal name ty info)) }
349 tcIfaceDecl ignore_prags
350 (IfaceData {ifName = occ_name,
352 ifCtxt = ctxt, ifGadtSyntax = gadt_syn,
355 ifGeneric = want_generic,
356 ifFamInst = mb_family })
357 = do { tc_name <- lookupIfaceTop occ_name
358 ; bindIfaceTyVars tv_bndrs $ \ tyvars -> do
360 { tycon <- fixM ( \ tycon -> do
361 { stupid_theta <- tcIfaceCtxt ctxt
364 Nothing -> return Nothing
366 do { famTyCon <- tcIfaceTyCon fam
367 ; insttys <- mapM tcIfaceType tys
368 ; return $ Just (famTyCon, insttys)
370 ; cons <- tcIfaceDataCons tc_name tycon tyvars rdr_cons
371 ; buildAlgTyCon tc_name tyvars stupid_theta
372 cons is_rec want_generic gadt_syn famInst
374 ; traceIf (text "tcIfaceDecl4" <+> ppr tycon)
375 ; return (ATyCon tycon)
378 tcIfaceDecl ignore_prags
379 (IfaceSyn {ifName = occ_name, ifTyVars = tv_bndrs,
380 ifOpenSyn = isOpen, ifSynRhs = rdr_rhs_ty})
381 = bindIfaceTyVars tv_bndrs $ \ tyvars -> do
382 { tc_name <- lookupIfaceTop occ_name
383 ; rhs_tyki <- tcIfaceType rdr_rhs_ty
384 ; let rhs = if isOpen then OpenSynTyCon rhs_tyki Nothing
385 else SynonymTyCon rhs_tyki
386 -- !!!TODO: read mb_family info from iface and pass as last argument
387 ; tycon <- buildSynTyCon tc_name tyvars rhs Nothing
388 ; return $ ATyCon tycon
391 tcIfaceDecl ignore_prags
392 (IfaceClass {ifCtxt = rdr_ctxt, ifName = occ_name,
393 ifTyVars = tv_bndrs, ifFDs = rdr_fds,
394 ifATs = rdr_ats, ifSigs = rdr_sigs,
396 -- ToDo: in hs-boot files we should really treat abstract classes specially,
397 -- as we do abstract tycons
398 = bindIfaceTyVars tv_bndrs $ \ tyvars -> do
399 { cls_name <- lookupIfaceTop occ_name
400 ; ctxt <- tcIfaceCtxt rdr_ctxt
401 ; sigs <- mappM tc_sig rdr_sigs
402 ; fds <- mappM tc_fd rdr_fds
403 ; ats' <- mappM (tcIfaceDecl ignore_prags) rdr_ats
404 ; let ats = zipWith setTyThingPoss ats' (map ifTyVars rdr_ats)
405 ; cls <- buildClass cls_name tyvars ctxt fds ats sigs tc_isrec
406 ; return (AClass cls) }
408 tc_sig (IfaceClassOp occ dm rdr_ty)
409 = do { op_name <- lookupIfaceTop occ
410 ; op_ty <- forkM (mk_doc op_name rdr_ty) (tcIfaceType rdr_ty)
411 -- Must be done lazily for just the same reason as the
412 -- type of a data con; to avoid sucking in types that
413 -- it mentions unless it's necessray to do so
414 ; return (op_name, dm, op_ty) }
416 mk_doc op_name op_ty = ptext SLIT("Class op") <+> sep [ppr op_name, ppr op_ty]
418 tc_fd (tvs1, tvs2) = do { tvs1' <- mappM tcIfaceTyVar tvs1
419 ; tvs2' <- mappM tcIfaceTyVar tvs2
420 ; return (tvs1', tvs2') }
422 -- For each AT argument compute the position of the corresponding class
423 -- parameter in the class head. This will later serve as a permutation
424 -- vector when checking the validity of instance declarations.
425 setTyThingPoss (ATyCon tycon) atTyVars =
426 let classTyVars = map fst tv_bndrs
428 . map ((`elemIndex` classTyVars) . fst)
430 -- There will be no Nothing, as we already passed renaming
432 ATyCon (setTyConArgPoss tycon poss)
433 setTyThingPoss _ _ = panic "TcIface.setTyThingPoss"
435 tcIfaceDecl ignore_prags (IfaceForeign {ifName = rdr_name, ifExtName = ext_name})
436 = do { name <- lookupIfaceTop rdr_name
437 ; return (ATyCon (mkForeignTyCon name ext_name
440 tcIfaceDataCons tycon_name tycon tc_tyvars if_cons
442 IfAbstractTyCon -> return mkAbstractTyConRhs
443 IfOpenDataTyCon -> return mkOpenDataTyConRhs
444 IfOpenNewTyCon -> return mkOpenNewTyConRhs
445 IfDataTyCon cons -> do { data_cons <- mappM tc_con_decl cons
446 ; return (mkDataTyConRhs data_cons) }
447 IfNewTyCon con -> do { data_con <- tc_con_decl con
448 ; mkNewTyConRhs tycon_name tycon data_con }
450 tc_con_decl (IfCon { ifConInfix = is_infix,
451 ifConUnivTvs = univ_tvs, ifConExTvs = ex_tvs,
452 ifConOcc = occ, ifConCtxt = ctxt, ifConEqSpec = spec,
453 ifConArgTys = args, ifConFields = field_lbls,
454 ifConStricts = stricts})
455 = bindIfaceTyVars univ_tvs $ \ univ_tyvars -> do
456 bindIfaceTyVars ex_tvs $ \ ex_tyvars -> do
457 { name <- lookupIfaceTop occ
458 ; eq_spec <- tcIfaceEqSpec spec
459 ; theta <- tcIfaceCtxt ctxt -- Laziness seems not worth the bother here
460 -- At one stage I thought that this context checking *had*
461 -- to be lazy, because of possible mutual recursion between the
462 -- type and the classe:
464 -- class Real a where { toRat :: a -> Ratio Integer }
465 -- data (Real a) => Ratio a = ...
466 -- But now I think that the laziness in checking class ops breaks
467 -- the loop, so no laziness needed
469 -- Read the argument types, but lazily to avoid faulting in
470 -- the component types unless they are really needed
471 ; arg_tys <- forkM (mk_doc name) (mappM tcIfaceType args)
472 ; lbl_names <- mappM lookupIfaceTop field_lbls
474 ; buildDataCon name is_infix {- Not infix -}
476 univ_tyvars ex_tyvars
480 mk_doc con_name = ptext SLIT("Constructor") <+> ppr con_name
485 do_item (occ, if_ty) = do { tv <- tcIfaceTyVar (occNameFS occ)
486 ; ty <- tcIfaceType if_ty
491 %************************************************************************
495 %************************************************************************
498 tcIfaceInst :: IfaceInst -> IfL Instance
499 tcIfaceInst (IfaceInst { ifDFun = dfun_occ, ifOFlag = oflag,
500 ifInstCls = cls, ifInstTys = mb_tcs,
502 = do { dfun <- forkM (ptext SLIT("Dict fun") <+> ppr dfun_occ) $
503 tcIfaceExtId dfun_occ
504 ; let mb_tcs' = map (fmap ifaceTyConName) mb_tcs
505 ; return (mkImportedInstance cls mb_tcs' dfun oflag) }
507 tcIfaceFamInst :: IfaceFamInst -> IfL FamInst
508 tcIfaceFamInst (IfaceFamInst { ifFamInstTyCon = tycon,
509 ifFamInstFam = fam, ifFamInstTys = mb_tcs })
510 -- = do { tycon' <- forkM (ptext SLIT("Inst tycon") <+> ppr tycon) $
511 -- ^^^this line doesn't work, but vvv this does => CPP in Haskell = evil!
512 = do { tycon' <- forkM (text ("Inst tycon") <+> ppr tycon) $
514 ; let mb_tcs' = map (fmap ifaceTyConName) mb_tcs
515 ; return (mkImportedFamInst fam mb_tcs' tycon') }
519 %************************************************************************
523 %************************************************************************
525 We move a IfaceRule from eps_rules to eps_rule_base when all its LHS free vars
526 are in the type environment. However, remember that typechecking a Rule may
527 (as a side effect) augment the type envt, and so we may need to iterate the process.
530 tcIfaceRules :: Bool -- True <=> ignore rules
533 tcIfaceRules ignore_prags if_rules
534 | ignore_prags = return []
535 | otherwise = mapM tcIfaceRule if_rules
537 tcIfaceRule :: IfaceRule -> IfL CoreRule
538 tcIfaceRule (IfaceRule {ifRuleName = name, ifActivation = act, ifRuleBndrs = bndrs,
539 ifRuleHead = fn, ifRuleArgs = args, ifRuleRhs = rhs,
541 = do { ~(bndrs', args', rhs') <-
542 -- Typecheck the payload lazily, in the hope it'll never be looked at
543 forkM (ptext SLIT("Rule") <+> ftext name) $
544 bindIfaceBndrs bndrs $ \ bndrs' ->
545 do { args' <- mappM tcIfaceExpr args
546 ; rhs' <- tcIfaceExpr rhs
547 ; return (bndrs', args', rhs') }
548 ; let mb_tcs = map ifTopFreeName args
550 ; returnM (Rule { ru_name = name, ru_fn = fn, ru_act = act,
551 ru_bndrs = bndrs', ru_args = args',
554 ru_local = False }) } -- An imported RULE is never for a local Id
555 -- or, even if it is (module loop, perhaps)
556 -- we'll just leave it in the non-local set
558 -- This function *must* mirror exactly what Rules.topFreeName does
559 -- We could have stored the ru_rough field in the iface file
560 -- but that would be redundant, I think.
561 -- The only wrinkle is that we must not be deceived by
562 -- type syononyms at the top of a type arg. Since
563 -- we can't tell at this point, we are careful not
564 -- to write them out in coreRuleToIfaceRule
565 ifTopFreeName :: IfaceExpr -> Maybe Name
566 ifTopFreeName (IfaceType (IfaceTyConApp tc _ )) = Just (ifaceTyConName tc)
567 ifTopFreeName (IfaceApp f a) = ifTopFreeName f
568 ifTopFreeName (IfaceExt n) = Just n
569 ifTopFreeName other = Nothing
573 %************************************************************************
577 %************************************************************************
580 tcIfaceType :: IfaceType -> IfL Type
581 tcIfaceType (IfaceTyVar n) = do { tv <- tcIfaceTyVar n; return (TyVarTy tv) }
582 tcIfaceType (IfaceAppTy t1 t2) = do { t1' <- tcIfaceType t1; t2' <- tcIfaceType t2; return (AppTy t1' t2') }
583 tcIfaceType (IfaceFunTy t1 t2) = do { t1' <- tcIfaceType t1; t2' <- tcIfaceType t2; return (FunTy t1' t2') }
584 tcIfaceType (IfaceTyConApp tc ts) = do { tc' <- tcIfaceTyCon tc; ts' <- tcIfaceTypes ts; return (mkTyConApp tc' ts') }
585 tcIfaceType (IfaceForAllTy tv t) = bindIfaceTyVar tv $ \ tv' -> do { t' <- tcIfaceType t; return (ForAllTy tv' t') }
586 tcIfaceType (IfacePredTy st) = do { st' <- tcIfacePredType st; return (PredTy st') }
588 tcIfaceTypes tys = mapM tcIfaceType tys
590 -----------------------------------------
591 tcIfacePredType :: IfacePredType -> IfL PredType
592 tcIfacePredType (IfaceClassP cls ts) = do { cls' <- tcIfaceClass cls; ts' <- tcIfaceTypes ts; return (ClassP cls' ts') }
593 tcIfacePredType (IfaceIParam ip t) = do { ip' <- newIPName ip; t' <- tcIfaceType t; return (IParam ip' t') }
594 tcIfacePredType (IfaceEqPred t1 t2) = do { t1' <- tcIfaceType t1; t2' <- tcIfaceType t2; return (EqPred t1' t2') }
596 -----------------------------------------
597 tcIfaceCtxt :: IfaceContext -> IfL ThetaType
598 tcIfaceCtxt sts = mappM tcIfacePredType sts
602 %************************************************************************
606 %************************************************************************
609 tcIfaceExpr :: IfaceExpr -> IfL CoreExpr
610 tcIfaceExpr (IfaceType ty)
611 = tcIfaceType ty `thenM` \ ty' ->
614 tcIfaceExpr (IfaceLcl name)
615 = tcIfaceLclId name `thenM` \ id ->
618 tcIfaceExpr (IfaceExt gbl)
619 = tcIfaceExtId gbl `thenM` \ id ->
622 tcIfaceExpr (IfaceLit lit)
625 tcIfaceExpr (IfaceFCall cc ty)
626 = tcIfaceType ty `thenM` \ ty' ->
627 newUnique `thenM` \ u ->
628 returnM (Var (mkFCallId u cc ty'))
630 tcIfaceExpr (IfaceTuple boxity args)
631 = mappM tcIfaceExpr args `thenM` \ args' ->
633 -- Put the missing type arguments back in
634 con_args = map (Type . exprType) args' ++ args'
636 returnM (mkApps (Var con_id) con_args)
639 con_id = dataConWorkId (tupleCon boxity arity)
642 tcIfaceExpr (IfaceLam bndr body)
643 = bindIfaceBndr bndr $ \ bndr' ->
644 tcIfaceExpr body `thenM` \ body' ->
645 returnM (Lam bndr' body')
647 tcIfaceExpr (IfaceApp fun arg)
648 = tcIfaceExpr fun `thenM` \ fun' ->
649 tcIfaceExpr arg `thenM` \ arg' ->
650 returnM (App fun' arg')
652 tcIfaceExpr (IfaceCase scrut case_bndr ty alts)
653 = tcIfaceExpr scrut `thenM` \ scrut' ->
654 newIfaceName (mkVarOccFS case_bndr) `thenM` \ case_bndr_name ->
656 scrut_ty = exprType scrut'
657 case_bndr' = mkLocalId case_bndr_name scrut_ty
658 tc_app = splitTyConApp scrut_ty
659 -- NB: Won't always succeed (polymoprhic case)
660 -- but won't be demanded in those cases
661 -- NB: not tcSplitTyConApp; we are looking at Core here
662 -- look through non-rec newtypes to find the tycon that
663 -- corresponds to the datacon in this case alternative
665 extendIfaceIdEnv [case_bndr'] $
666 mappM (tcIfaceAlt tc_app) alts `thenM` \ alts' ->
667 tcIfaceType ty `thenM` \ ty' ->
668 returnM (Case scrut' case_bndr' ty' alts')
670 tcIfaceExpr (IfaceLet (IfaceNonRec bndr rhs) body)
671 = do { rhs' <- tcIfaceExpr rhs
672 ; id <- tcIfaceLetBndr bndr
673 ; body' <- extendIfaceIdEnv [id] (tcIfaceExpr body)
674 ; return (Let (NonRec id rhs') body') }
676 tcIfaceExpr (IfaceLet (IfaceRec pairs) body)
677 = do { ids <- mapM tcIfaceLetBndr bndrs
678 ; extendIfaceIdEnv ids $ do
679 { rhss' <- mapM tcIfaceExpr rhss
680 ; body' <- tcIfaceExpr body
681 ; return (Let (Rec (ids `zip` rhss')) body') } }
683 (bndrs, rhss) = unzip pairs
685 tcIfaceExpr (IfaceCast expr co) = do
686 expr' <- tcIfaceExpr expr
687 co' <- tcIfaceType co
688 returnM (Cast expr' co')
690 tcIfaceExpr (IfaceNote note expr)
691 = tcIfaceExpr expr `thenM` \ expr' ->
693 IfaceInlineMe -> returnM (Note InlineMe expr')
694 IfaceSCC cc -> returnM (Note (SCC cc) expr')
695 IfaceCoreNote n -> returnM (Note (CoreNote n) expr')
697 -------------------------
698 tcIfaceAlt _ (IfaceDefault, names, rhs)
699 = ASSERT( null names )
700 tcIfaceExpr rhs `thenM` \ rhs' ->
701 returnM (DEFAULT, [], rhs')
703 tcIfaceAlt _ (IfaceLitAlt lit, names, rhs)
704 = ASSERT( null names )
705 tcIfaceExpr rhs `thenM` \ rhs' ->
706 returnM (LitAlt lit, [], rhs')
708 -- A case alternative is made quite a bit more complicated
709 -- by the fact that we omit type annotations because we can
710 -- work them out. True enough, but its not that easy!
711 tcIfaceAlt (tycon, inst_tys) (IfaceDataAlt data_occ, arg_strs, rhs)
712 = do { con <- tcIfaceDataCon data_occ
713 ; ASSERT2( con `elem` tyConDataCons tycon,
714 ppr con $$ ppr tycon $$ ppr (tyConDataCons tycon) )
715 tcIfaceDataAlt con inst_tys arg_strs rhs }
717 tcIfaceAlt (tycon, inst_tys) (IfaceTupleAlt boxity, arg_occs, rhs)
718 = ASSERT( isTupleTyCon tycon )
719 do { let [data_con] = tyConDataCons tycon
720 ; tcIfaceDataAlt data_con inst_tys arg_occs rhs }
722 tcIfaceDataAlt con inst_tys arg_strs rhs
723 = do { us <- newUniqueSupply
724 ; let uniqs = uniqsFromSupply us
725 ; let (ex_tvs, co_tvs, arg_ids)
726 = dataConRepFSInstPat arg_strs uniqs con inst_tys
727 all_tvs = ex_tvs ++ co_tvs
729 ; rhs' <- extendIfaceTyVarEnv all_tvs $
730 extendIfaceIdEnv arg_ids $
732 ; return (DataAlt con, all_tvs ++ arg_ids, rhs') }
737 tcExtCoreBindings :: [IfaceBinding] -> IfL [CoreBind] -- Used for external core
738 tcExtCoreBindings [] = return []
739 tcExtCoreBindings (b:bs) = do_one b (tcExtCoreBindings bs)
741 do_one :: IfaceBinding -> IfL [CoreBind] -> IfL [CoreBind]
742 do_one (IfaceNonRec bndr rhs) thing_inside
743 = do { rhs' <- tcIfaceExpr rhs
744 ; bndr' <- newExtCoreBndr bndr
745 ; extendIfaceIdEnv [bndr'] $ do
746 { core_binds <- thing_inside
747 ; return (NonRec bndr' rhs' : core_binds) }}
749 do_one (IfaceRec pairs) thing_inside
750 = do { bndrs' <- mappM newExtCoreBndr bndrs
751 ; extendIfaceIdEnv bndrs' $ do
752 { rhss' <- mappM tcIfaceExpr rhss
753 ; core_binds <- thing_inside
754 ; return (Rec (bndrs' `zip` rhss') : core_binds) }}
756 (bndrs,rhss) = unzip pairs
760 %************************************************************************
764 %************************************************************************
767 tcIdInfo :: Bool -> Name -> Type -> IfaceIdInfo -> IfL IdInfo
768 tcIdInfo ignore_prags name ty info
769 | ignore_prags = return vanillaIdInfo
770 | otherwise = case info of
771 NoInfo -> return vanillaIdInfo
772 HasInfo info -> foldlM tcPrag init_info info
774 -- Set the CgInfo to something sensible but uninformative before
775 -- we start; default assumption is that it has CAFs
776 init_info = vanillaIdInfo
778 tcPrag info HsNoCafRefs = returnM (info `setCafInfo` NoCafRefs)
779 tcPrag info (HsArity arity) = returnM (info `setArityInfo` arity)
780 tcPrag info (HsStrictness str) = returnM (info `setAllStrictnessInfo` Just str)
782 -- The next two are lazy, so they don't transitively suck stuff in
783 tcPrag info (HsWorker nm arity) = tcWorkerInfo ty info nm arity
784 tcPrag info (HsInline inline_prag) = returnM (info `setInlinePragInfo` inline_prag)
785 tcPrag info (HsUnfold expr)
786 = tcPragExpr name expr `thenM` \ maybe_expr' ->
788 -- maybe_expr' doesn't get looked at if the unfolding
789 -- is never inspected; so the typecheck doesn't even happen
790 unfold_info = case maybe_expr' of
791 Nothing -> noUnfolding
792 Just expr' -> mkTopUnfolding expr'
794 returnM (info `setUnfoldingInfoLazily` unfold_info)
798 tcWorkerInfo ty info wkr arity
799 = do { mb_wkr_id <- forkM_maybe doc (tcIfaceExtId wkr)
801 -- We return without testing maybe_wkr_id, but as soon as info is
802 -- looked at we will test it. That's ok, because its outside the
803 -- knot; and there seems no big reason to further defer the
804 -- tcIfaceId lookup. (Contrast with tcPragExpr, where postponing walking
805 -- over the unfolding until it's actually used does seem worth while.)
806 ; us <- newUniqueSupply
808 ; returnM (case mb_wkr_id of
810 Just wkr_id -> add_wkr_info us wkr_id info) }
812 doc = text "Worker for" <+> ppr wkr
813 add_wkr_info us wkr_id info
814 = info `setUnfoldingInfoLazily` mk_unfolding us wkr_id
815 `setWorkerInfo` HasWorker wkr_id arity
817 mk_unfolding us wkr_id = mkTopUnfolding (initUs_ us (mkWrapper ty strict_sig) wkr_id)
819 -- We are relying here on strictness info always appearing
820 -- before worker info, fingers crossed ....
821 strict_sig = case newStrictnessInfo info of
823 Nothing -> pprPanic "Worker info but no strictness for" (ppr wkr)
826 For unfoldings we try to do the job lazily, so that we never type check
827 an unfolding that isn't going to be looked at.
830 tcPragExpr :: Name -> IfaceExpr -> IfL (Maybe CoreExpr)
833 tcIfaceExpr expr `thenM` \ core_expr' ->
835 -- Check for type consistency in the unfolding
836 ifOptM Opt_DoCoreLinting (
837 get_in_scope_ids `thenM` \ in_scope ->
838 case lintUnfolding noSrcLoc in_scope core_expr' of
839 Nothing -> returnM ()
840 Just fail_msg -> pprPanic "Iface Lint failure" (hang doc 2 fail_msg)
845 doc = text "Unfolding of" <+> ppr name
846 get_in_scope_ids -- Urgh; but just for linting
848 do { env <- getGblEnv
849 ; case if_rec_types env of {
850 Nothing -> return [] ;
851 Just (_, get_env) -> do
852 { type_env <- get_env
853 ; return (typeEnvIds type_env) }}}
858 %************************************************************************
860 Getting from Names to TyThings
862 %************************************************************************
865 tcIfaceGlobal :: Name -> IfL TyThing
867 | Just thing <- wiredInNameTyThing_maybe name
868 -- Wired-in things include TyCons, DataCons, and Ids
869 = do { ifCheckWiredInThing name; return thing }
871 = do { (eps,hpt) <- getEpsAndHpt
873 ; case lookupType dflags hpt (eps_PTE eps) name of {
874 Just thing -> return thing ;
878 ; case if_rec_types env of {
879 Just (mod, get_type_env)
880 | nameIsLocalOrFrom mod name
881 -> do -- It's defined in the module being compiled
882 { type_env <- setLclEnv () get_type_env -- yuk
883 ; case lookupNameEnv type_env name of
884 Just thing -> return thing
885 Nothing -> pprPanic "tcIfaceGlobal (local): not found:"
886 (ppr name $$ ppr type_env) }
890 { mb_thing <- importDecl name -- It's imported; go get it
892 Failed err -> failIfM err
893 Succeeded thing -> return thing
896 ifCheckWiredInThing :: Name -> IfL ()
897 -- Even though we are in an interface file, we want to make
898 -- sure the instances of a wired-in thing are loaded (imagine f :: Double -> Double)
899 -- Ditto want to ensure that RULES are loaded too
900 ifCheckWiredInThing name
901 = do { mod <- getIfModule
902 -- Check whether we are typechecking the interface for this
903 -- very module. E.g when compiling the base library in --make mode
904 -- we may typecheck GHC.Base.hi. At that point, GHC.Base is not in
905 -- the HPT, so without the test we'll demand-load it into the PIT!
906 -- C.f. the same test in checkWiredInTyCon above
907 ; unless (mod == nameModule name)
908 (loadWiredInHomeIface name) }
910 tcIfaceTyCon :: IfaceTyCon -> IfL TyCon
911 tcIfaceTyCon IfaceIntTc = tcWiredInTyCon intTyCon
912 tcIfaceTyCon IfaceBoolTc = tcWiredInTyCon boolTyCon
913 tcIfaceTyCon IfaceCharTc = tcWiredInTyCon charTyCon
914 tcIfaceTyCon IfaceListTc = tcWiredInTyCon listTyCon
915 tcIfaceTyCon IfacePArrTc = tcWiredInTyCon parrTyCon
916 tcIfaceTyCon (IfaceTupTc bx ar) = tcWiredInTyCon (tupleTyCon bx ar)
917 tcIfaceTyCon (IfaceTc name) = do { thing <- tcIfaceGlobal name
918 ; return (check_tc (tyThingTyCon thing)) }
921 check_tc tc = case toIfaceTyCon tc of
923 other -> pprTrace "check_tc" (ppr tc) tc
927 -- we should be okay just returning Kind constructors without extra loading
928 tcIfaceTyCon IfaceLiftedTypeKindTc = return liftedTypeKindTyCon
929 tcIfaceTyCon IfaceOpenTypeKindTc = return openTypeKindTyCon
930 tcIfaceTyCon IfaceUnliftedTypeKindTc = return unliftedTypeKindTyCon
931 tcIfaceTyCon IfaceArgTypeKindTc = return argTypeKindTyCon
932 tcIfaceTyCon IfaceUbxTupleKindTc = return ubxTupleKindTyCon
934 -- Even though we are in an interface file, we want to make
935 -- sure the instances and RULES of this tycon are loaded
936 -- Imagine: f :: Double -> Double
937 tcWiredInTyCon :: TyCon -> IfL TyCon
938 tcWiredInTyCon tc = do { ifCheckWiredInThing (tyConName tc)
941 tcIfaceClass :: Name -> IfL Class
942 tcIfaceClass name = do { thing <- tcIfaceGlobal name
943 ; return (tyThingClass thing) }
945 tcIfaceDataCon :: Name -> IfL DataCon
946 tcIfaceDataCon name = do { thing <- tcIfaceGlobal name
948 ADataCon dc -> return dc
949 other -> pprPanic "tcIfaceExtDC" (ppr name$$ ppr thing) }
951 tcIfaceExtId :: Name -> IfL Id
952 tcIfaceExtId name = do { thing <- tcIfaceGlobal name
955 other -> pprPanic "tcIfaceExtId" (ppr name$$ ppr thing) }
958 %************************************************************************
962 %************************************************************************
965 bindIfaceBndr :: IfaceBndr -> (CoreBndr -> IfL a) -> IfL a
966 bindIfaceBndr (IfaceIdBndr (fs, ty)) thing_inside
967 = do { name <- newIfaceName (mkVarOccFS fs)
968 ; ty' <- tcIfaceType ty
969 ; let id = mkLocalId name ty'
970 ; extendIfaceIdEnv [id] (thing_inside id) }
971 bindIfaceBndr (IfaceTvBndr bndr) thing_inside
972 = bindIfaceTyVar bndr thing_inside
974 bindIfaceBndrs :: [IfaceBndr] -> ([CoreBndr] -> IfL a) -> IfL a
975 bindIfaceBndrs [] thing_inside = thing_inside []
976 bindIfaceBndrs (b:bs) thing_inside
977 = bindIfaceBndr b $ \ b' ->
978 bindIfaceBndrs bs $ \ bs' ->
979 thing_inside (b':bs')
981 -----------------------
982 tcIfaceLetBndr (IfLetBndr fs ty info)
983 = do { name <- newIfaceName (mkVarOccFS fs)
984 ; ty' <- tcIfaceType ty
986 NoInfo -> return (mkLocalId name ty')
987 HasInfo i -> return (mkLocalIdWithInfo name ty' (tc_info i)) }
989 -- Similar to tcIdInfo, but much simpler
990 tc_info [] = vanillaIdInfo
991 tc_info (HsInline p : i) = tc_info i `setInlinePragInfo` p
992 tc_info (HsArity a : i) = tc_info i `setArityInfo` a
993 tc_info (HsStrictness s : i) = tc_info i `setAllStrictnessInfo` Just s
994 tc_info (other : i) = pprTrace "tcIfaceLetBndr: discarding unexpected IdInfo"
995 (ppr other) (tc_info i)
997 -----------------------
998 newExtCoreBndr :: IfaceLetBndr -> IfL Id
999 newExtCoreBndr (IfLetBndr var ty _) -- Ignoring IdInfo for now
1000 = do { mod <- getIfModule
1001 ; name <- newGlobalBinder mod (mkVarOccFS var) noSrcLoc
1002 ; ty' <- tcIfaceType ty
1003 ; return (mkLocalId name ty') }
1005 -----------------------
1006 bindIfaceTyVar :: IfaceTvBndr -> (TyVar -> IfL a) -> IfL a
1007 bindIfaceTyVar (occ,kind) thing_inside
1008 = do { name <- newIfaceName (mkTyVarOcc occ)
1009 ; tyvar <- mk_iface_tyvar name kind
1010 ; extendIfaceTyVarEnv [tyvar] (thing_inside tyvar) }
1012 bindIfaceTyVars :: [IfaceTvBndr] -> ([TyVar] -> IfL a) -> IfL a
1013 bindIfaceTyVars bndrs thing_inside
1014 = do { names <- newIfaceNames (map mkTyVarOcc occs)
1015 ; tyvars <- TcRnMonad.zipWithM mk_iface_tyvar names kinds
1016 ; extendIfaceTyVarEnv tyvars (thing_inside tyvars) }
1018 (occs,kinds) = unzip bndrs
1020 mk_iface_tyvar :: Name -> IfaceKind -> IfL TyVar
1021 mk_iface_tyvar name ifKind
1022 = do { kind <- tcIfaceType ifKind
1023 ; if isCoercionKind kind then
1024 return (Var.mkCoVar name kind)
1026 return (Var.mkTyVar name kind) }