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)
202 -- Vectorisation information
203 ; let vect_info = VectInfo
204 (mkNameSet (ifaceVectInfoCCVar (mi_vect_info iface)))
207 ; exports <- ifaceExportNames (mi_exports iface)
210 ; traceIf (vcat [text "Finished typechecking interface for" <+> ppr (mi_module iface),
211 text "Type envt:" <+> ppr type_env])
212 ; return $ ModDetails { md_types = type_env
214 , md_fam_insts = fam_insts
216 , md_vect_info = vect_info
217 , md_exports = exports
218 , md_modBreaks = emptyModBreaks
224 %************************************************************************
226 Type and class declarations
228 %************************************************************************
231 tcHiBootIface :: HscSource -> Module -> TcRn ModDetails
232 -- Load the hi-boot iface for the module being compiled,
233 -- if it indeed exists in the transitive closure of imports
234 -- Return the ModDetails, empty if no hi-boot iface
235 tcHiBootIface hsc_src mod
236 | isHsBoot hsc_src -- Already compiling a hs-boot file
237 = return emptyModDetails
239 = do { traceIf (text "loadHiBootInterface" <+> ppr mod)
242 ; if not (isOneShot mode)
243 -- In --make and interactive mode, if this module has an hs-boot file
244 -- we'll have compiled it already, and it'll be in the HPT
246 -- We check wheher the interface is a *boot* interface.
247 -- It can happen (when using GHC from Visual Studio) that we
248 -- compile a module in TypecheckOnly mode, with a stable,
249 -- fully-populated HPT. In that case the boot interface isn't there
250 -- (it's been replaced by the mother module) so we can't check it.
251 -- And that's fine, because if M's ModInfo is in the HPT, then
252 -- it's been compiled once, and we don't need to check the boot iface
253 then do { hpt <- getHpt
254 ; case lookupUFM hpt (moduleName mod) of
255 Just info | mi_boot (hm_iface info)
256 -> return (hm_details info)
257 other -> return emptyModDetails }
260 -- OK, so we're in one-shot mode.
261 -- In that case, we're read all the direct imports by now,
262 -- so eps_is_boot will record if any of our imports mention us by
263 -- way of hi-boot file
265 ; case lookupUFM (eps_is_boot eps) (moduleName mod) of {
266 Nothing -> return emptyModDetails ; -- The typical case
268 Just (_, False) -> failWithTc moduleLoop ;
269 -- Someone below us imported us!
270 -- This is a loop with no hi-boot in the way
272 Just (_mod, True) -> -- There's a hi-boot interface below us
274 do { read_result <- findAndReadIface
278 ; case read_result of
279 Failed err -> failWithTc (elaborate err)
280 Succeeded (iface, _path) -> typecheckIface iface
283 need = ptext SLIT("Need the hi-boot interface for") <+> ppr mod
284 <+> ptext SLIT("to compare against the Real Thing")
286 moduleLoop = ptext SLIT("Circular imports: module") <+> quotes (ppr mod)
287 <+> ptext SLIT("depends on itself")
289 elaborate err = hang (ptext SLIT("Could not find hi-boot interface for") <+>
290 quotes (ppr mod) <> colon) 4 err
294 %************************************************************************
296 Type and class declarations
298 %************************************************************************
300 When typechecking a data type decl, we *lazily* (via forkM) typecheck
301 the constructor argument types. This is in the hope that we may never
302 poke on those argument types, and hence may never need to load the
303 interface files for types mentioned in the arg types.
306 data Foo.S = MkS Baz.T
307 Mabye we can get away without even loading the interface for Baz!
309 This is not just a performance thing. Suppose we have
310 data Foo.S = MkS Baz.T
311 data Baz.T = MkT Foo.S
312 (in different interface files, of course).
313 Now, first we load and typecheck Foo.S, and add it to the type envt.
314 If we do explore MkS's argument, we'll load and typecheck Baz.T.
315 If we explore MkT's argument we'll find Foo.S already in the envt.
317 If we typechecked constructor args eagerly, when loading Foo.S we'd try to
318 typecheck the type Baz.T. So we'd fault in Baz.T... and then need Foo.S...
319 which isn't done yet.
321 All very cunning. However, there is a rather subtle gotcha which bit
322 me when developing this stuff. When we typecheck the decl for S, we
323 extend the type envt with S, MkS, and all its implicit Ids. Suppose
324 (a bug, but it happened) that the list of implicit Ids depended in
325 turn on the constructor arg types. Then the following sequence of
327 * we build a thunk <t> for the constructor arg tys
328 * we build a thunk for the extended type environment (depends on <t>)
329 * we write the extended type envt into the global EPS mutvar
331 Now we look something up in the type envt
333 * which reads the global type envt out of the global EPS mutvar
334 * but that depends in turn on <t>
336 It's subtle, because, it'd work fine if we typechecked the constructor args
337 eagerly -- they don't need the extended type envt. They just get the extended
338 type envt by accident, because they look at it later.
340 What this means is that the implicitTyThings MUST NOT DEPEND on any of
345 tcIfaceDecl :: Bool -- True <=> discard IdInfo on IfaceId bindings
349 tcIfaceDecl ignore_prags (IfaceId {ifName = occ_name, ifType = iface_type, ifIdInfo = info})
350 = do { name <- lookupIfaceTop occ_name
351 ; ty <- tcIfaceType iface_type
352 ; info <- tcIdInfo ignore_prags name ty info
353 ; return (AnId (mkVanillaGlobal name ty info)) }
355 tcIfaceDecl ignore_prags
356 (IfaceData {ifName = occ_name,
358 ifCtxt = ctxt, ifGadtSyntax = gadt_syn,
361 ifGeneric = want_generic,
362 ifFamInst = mb_family })
363 = do { tc_name <- lookupIfaceTop occ_name
364 ; bindIfaceTyVars tv_bndrs $ \ tyvars -> do
366 { tycon <- fixM ( \ tycon -> do
367 { stupid_theta <- tcIfaceCtxt ctxt
370 Nothing -> return Nothing
372 do { famTyCon <- tcIfaceTyCon fam
373 ; insttys <- mapM tcIfaceType tys
374 ; return $ Just (famTyCon, insttys)
376 ; cons <- tcIfaceDataCons tc_name tycon tyvars rdr_cons
377 ; buildAlgTyCon tc_name tyvars stupid_theta
378 cons is_rec want_generic gadt_syn famInst
380 ; traceIf (text "tcIfaceDecl4" <+> ppr tycon)
381 ; return (ATyCon tycon)
384 tcIfaceDecl ignore_prags
385 (IfaceSyn {ifName = occ_name, ifTyVars = tv_bndrs,
386 ifOpenSyn = isOpen, ifSynRhs = rdr_rhs_ty})
387 = bindIfaceTyVars tv_bndrs $ \ tyvars -> do
388 { tc_name <- lookupIfaceTop occ_name
389 ; rhs_tyki <- tcIfaceType rdr_rhs_ty
390 ; let rhs = if isOpen then OpenSynTyCon rhs_tyki Nothing
391 else SynonymTyCon rhs_tyki
392 -- !!!TODO: read mb_family info from iface and pass as last argument
393 ; tycon <- buildSynTyCon tc_name tyvars rhs Nothing
394 ; return $ ATyCon tycon
397 tcIfaceDecl ignore_prags
398 (IfaceClass {ifCtxt = rdr_ctxt, ifName = occ_name,
399 ifTyVars = tv_bndrs, ifFDs = rdr_fds,
400 ifATs = rdr_ats, ifSigs = rdr_sigs,
402 -- ToDo: in hs-boot files we should really treat abstract classes specially,
403 -- as we do abstract tycons
404 = bindIfaceTyVars tv_bndrs $ \ tyvars -> do
405 { cls_name <- lookupIfaceTop occ_name
406 ; ctxt <- tcIfaceCtxt rdr_ctxt
407 ; sigs <- mappM tc_sig rdr_sigs
408 ; fds <- mappM tc_fd rdr_fds
409 ; ats' <- mappM (tcIfaceDecl ignore_prags) rdr_ats
410 ; let ats = zipWith setTyThingPoss ats' (map ifTyVars rdr_ats)
411 ; cls <- buildClass cls_name tyvars ctxt fds ats sigs tc_isrec
412 ; return (AClass cls) }
414 tc_sig (IfaceClassOp occ dm rdr_ty)
415 = do { op_name <- lookupIfaceTop occ
416 ; op_ty <- forkM (mk_doc op_name rdr_ty) (tcIfaceType rdr_ty)
417 -- Must be done lazily for just the same reason as the
418 -- type of a data con; to avoid sucking in types that
419 -- it mentions unless it's necessray to do so
420 ; return (op_name, dm, op_ty) }
422 mk_doc op_name op_ty = ptext SLIT("Class op") <+> sep [ppr op_name, ppr op_ty]
424 tc_fd (tvs1, tvs2) = do { tvs1' <- mappM tcIfaceTyVar tvs1
425 ; tvs2' <- mappM tcIfaceTyVar tvs2
426 ; return (tvs1', tvs2') }
428 -- For each AT argument compute the position of the corresponding class
429 -- parameter in the class head. This will later serve as a permutation
430 -- vector when checking the validity of instance declarations.
431 setTyThingPoss (ATyCon tycon) atTyVars =
432 let classTyVars = map fst tv_bndrs
434 . map ((`elemIndex` classTyVars) . fst)
436 -- There will be no Nothing, as we already passed renaming
438 ATyCon (setTyConArgPoss tycon poss)
439 setTyThingPoss _ _ = panic "TcIface.setTyThingPoss"
441 tcIfaceDecl ignore_prags (IfaceForeign {ifName = rdr_name, ifExtName = ext_name})
442 = do { name <- lookupIfaceTop rdr_name
443 ; return (ATyCon (mkForeignTyCon name ext_name
446 tcIfaceDataCons tycon_name tycon tc_tyvars if_cons
448 IfAbstractTyCon -> return mkAbstractTyConRhs
449 IfOpenDataTyCon -> return mkOpenDataTyConRhs
450 IfOpenNewTyCon -> return mkOpenNewTyConRhs
451 IfDataTyCon cons -> do { data_cons <- mappM tc_con_decl cons
452 ; return (mkDataTyConRhs data_cons) }
453 IfNewTyCon con -> do { data_con <- tc_con_decl con
454 ; mkNewTyConRhs tycon_name tycon data_con }
456 tc_con_decl (IfCon { ifConInfix = is_infix,
457 ifConUnivTvs = univ_tvs, ifConExTvs = ex_tvs,
458 ifConOcc = occ, ifConCtxt = ctxt, ifConEqSpec = spec,
459 ifConArgTys = args, ifConFields = field_lbls,
460 ifConStricts = stricts})
461 = bindIfaceTyVars univ_tvs $ \ univ_tyvars -> do
462 bindIfaceTyVars ex_tvs $ \ ex_tyvars -> do
463 { name <- lookupIfaceTop occ
464 ; eq_spec <- tcIfaceEqSpec spec
465 ; theta <- tcIfaceCtxt ctxt -- Laziness seems not worth the bother here
466 -- At one stage I thought that this context checking *had*
467 -- to be lazy, because of possible mutual recursion between the
468 -- type and the classe:
470 -- class Real a where { toRat :: a -> Ratio Integer }
471 -- data (Real a) => Ratio a = ...
472 -- But now I think that the laziness in checking class ops breaks
473 -- the loop, so no laziness needed
475 -- Read the argument types, but lazily to avoid faulting in
476 -- the component types unless they are really needed
477 ; arg_tys <- forkM (mk_doc name) (mappM tcIfaceType args)
478 ; lbl_names <- mappM lookupIfaceTop field_lbls
480 ; buildDataCon name is_infix {- Not infix -}
482 univ_tyvars ex_tyvars
486 mk_doc con_name = ptext SLIT("Constructor") <+> ppr con_name
491 do_item (occ, if_ty) = do { tv <- tcIfaceTyVar (occNameFS occ)
492 ; ty <- tcIfaceType if_ty
497 %************************************************************************
501 %************************************************************************
504 tcIfaceInst :: IfaceInst -> IfL Instance
505 tcIfaceInst (IfaceInst { ifDFun = dfun_occ, ifOFlag = oflag,
506 ifInstCls = cls, ifInstTys = mb_tcs,
508 = do { dfun <- forkM (ptext SLIT("Dict fun") <+> ppr dfun_occ) $
509 tcIfaceExtId dfun_occ
510 ; let mb_tcs' = map (fmap ifaceTyConName) mb_tcs
511 ; return (mkImportedInstance cls mb_tcs' dfun oflag) }
513 tcIfaceFamInst :: IfaceFamInst -> IfL FamInst
514 tcIfaceFamInst (IfaceFamInst { ifFamInstTyCon = tycon,
515 ifFamInstFam = fam, ifFamInstTys = mb_tcs })
516 -- = do { tycon' <- forkM (ptext SLIT("Inst tycon") <+> ppr tycon) $
517 -- ^^^this line doesn't work, but vvv this does => CPP in Haskell = evil!
518 = do { tycon' <- forkM (text ("Inst tycon") <+> ppr tycon) $
520 ; let mb_tcs' = map (fmap ifaceTyConName) mb_tcs
521 ; return (mkImportedFamInst fam mb_tcs' tycon') }
525 %************************************************************************
529 %************************************************************************
531 We move a IfaceRule from eps_rules to eps_rule_base when all its LHS free vars
532 are in the type environment. However, remember that typechecking a Rule may
533 (as a side effect) augment the type envt, and so we may need to iterate the process.
536 tcIfaceRules :: Bool -- True <=> ignore rules
539 tcIfaceRules ignore_prags if_rules
540 | ignore_prags = return []
541 | otherwise = mapM tcIfaceRule if_rules
543 tcIfaceRule :: IfaceRule -> IfL CoreRule
544 tcIfaceRule (IfaceRule {ifRuleName = name, ifActivation = act, ifRuleBndrs = bndrs,
545 ifRuleHead = fn, ifRuleArgs = args, ifRuleRhs = rhs,
547 = do { ~(bndrs', args', rhs') <-
548 -- Typecheck the payload lazily, in the hope it'll never be looked at
549 forkM (ptext SLIT("Rule") <+> ftext name) $
550 bindIfaceBndrs bndrs $ \ bndrs' ->
551 do { args' <- mappM tcIfaceExpr args
552 ; rhs' <- tcIfaceExpr rhs
553 ; return (bndrs', args', rhs') }
554 ; let mb_tcs = map ifTopFreeName args
556 ; returnM (Rule { ru_name = name, ru_fn = fn, ru_act = act,
557 ru_bndrs = bndrs', ru_args = args',
560 ru_local = False }) } -- An imported RULE is never for a local Id
561 -- or, even if it is (module loop, perhaps)
562 -- we'll just leave it in the non-local set
564 -- This function *must* mirror exactly what Rules.topFreeName does
565 -- We could have stored the ru_rough field in the iface file
566 -- but that would be redundant, I think.
567 -- The only wrinkle is that we must not be deceived by
568 -- type syononyms at the top of a type arg. Since
569 -- we can't tell at this point, we are careful not
570 -- to write them out in coreRuleToIfaceRule
571 ifTopFreeName :: IfaceExpr -> Maybe Name
572 ifTopFreeName (IfaceType (IfaceTyConApp tc _ )) = Just (ifaceTyConName tc)
573 ifTopFreeName (IfaceApp f a) = ifTopFreeName f
574 ifTopFreeName (IfaceExt n) = Just n
575 ifTopFreeName other = Nothing
579 %************************************************************************
583 %************************************************************************
586 tcIfaceType :: IfaceType -> IfL Type
587 tcIfaceType (IfaceTyVar n) = do { tv <- tcIfaceTyVar n; return (TyVarTy tv) }
588 tcIfaceType (IfaceAppTy t1 t2) = do { t1' <- tcIfaceType t1; t2' <- tcIfaceType t2; return (AppTy t1' t2') }
589 tcIfaceType (IfaceFunTy t1 t2) = do { t1' <- tcIfaceType t1; t2' <- tcIfaceType t2; return (FunTy t1' t2') }
590 tcIfaceType (IfaceTyConApp tc ts) = do { tc' <- tcIfaceTyCon tc; ts' <- tcIfaceTypes ts; return (mkTyConApp tc' ts') }
591 tcIfaceType (IfaceForAllTy tv t) = bindIfaceTyVar tv $ \ tv' -> do { t' <- tcIfaceType t; return (ForAllTy tv' t') }
592 tcIfaceType (IfacePredTy st) = do { st' <- tcIfacePredType st; return (PredTy st') }
594 tcIfaceTypes tys = mapM tcIfaceType tys
596 -----------------------------------------
597 tcIfacePredType :: IfacePredType -> IfL PredType
598 tcIfacePredType (IfaceClassP cls ts) = do { cls' <- tcIfaceClass cls; ts' <- tcIfaceTypes ts; return (ClassP cls' ts') }
599 tcIfacePredType (IfaceIParam ip t) = do { ip' <- newIPName ip; t' <- tcIfaceType t; return (IParam ip' t') }
600 tcIfacePredType (IfaceEqPred t1 t2) = do { t1' <- tcIfaceType t1; t2' <- tcIfaceType t2; return (EqPred t1' t2') }
602 -----------------------------------------
603 tcIfaceCtxt :: IfaceContext -> IfL ThetaType
604 tcIfaceCtxt sts = mappM tcIfacePredType sts
608 %************************************************************************
612 %************************************************************************
615 tcIfaceExpr :: IfaceExpr -> IfL CoreExpr
616 tcIfaceExpr (IfaceType ty)
617 = tcIfaceType ty `thenM` \ ty' ->
620 tcIfaceExpr (IfaceLcl name)
621 = tcIfaceLclId name `thenM` \ id ->
624 tcIfaceExpr (IfaceExt gbl)
625 = tcIfaceExtId gbl `thenM` \ id ->
628 tcIfaceExpr (IfaceLit lit)
631 tcIfaceExpr (IfaceFCall cc ty)
632 = tcIfaceType ty `thenM` \ ty' ->
633 newUnique `thenM` \ u ->
634 returnM (Var (mkFCallId u cc ty'))
636 tcIfaceExpr (IfaceTuple boxity args)
637 = mappM tcIfaceExpr args `thenM` \ args' ->
639 -- Put the missing type arguments back in
640 con_args = map (Type . exprType) args' ++ args'
642 returnM (mkApps (Var con_id) con_args)
645 con_id = dataConWorkId (tupleCon boxity arity)
648 tcIfaceExpr (IfaceLam bndr body)
649 = bindIfaceBndr bndr $ \ bndr' ->
650 tcIfaceExpr body `thenM` \ body' ->
651 returnM (Lam bndr' body')
653 tcIfaceExpr (IfaceApp fun arg)
654 = tcIfaceExpr fun `thenM` \ fun' ->
655 tcIfaceExpr arg `thenM` \ arg' ->
656 returnM (App fun' arg')
658 tcIfaceExpr (IfaceCase scrut case_bndr ty alts)
659 = tcIfaceExpr scrut `thenM` \ scrut' ->
660 newIfaceName (mkVarOccFS case_bndr) `thenM` \ case_bndr_name ->
662 scrut_ty = exprType scrut'
663 case_bndr' = mkLocalId case_bndr_name scrut_ty
664 tc_app = splitTyConApp scrut_ty
665 -- NB: Won't always succeed (polymoprhic case)
666 -- but won't be demanded in those cases
667 -- NB: not tcSplitTyConApp; we are looking at Core here
668 -- look through non-rec newtypes to find the tycon that
669 -- corresponds to the datacon in this case alternative
671 extendIfaceIdEnv [case_bndr'] $
672 mappM (tcIfaceAlt tc_app) alts `thenM` \ alts' ->
673 tcIfaceType ty `thenM` \ ty' ->
674 returnM (Case scrut' case_bndr' ty' alts')
676 tcIfaceExpr (IfaceLet (IfaceNonRec bndr rhs) body)
677 = do { rhs' <- tcIfaceExpr rhs
678 ; id <- tcIfaceLetBndr bndr
679 ; body' <- extendIfaceIdEnv [id] (tcIfaceExpr body)
680 ; return (Let (NonRec id rhs') body') }
682 tcIfaceExpr (IfaceLet (IfaceRec pairs) body)
683 = do { ids <- mapM tcIfaceLetBndr bndrs
684 ; extendIfaceIdEnv ids $ do
685 { rhss' <- mapM tcIfaceExpr rhss
686 ; body' <- tcIfaceExpr body
687 ; return (Let (Rec (ids `zip` rhss')) body') } }
689 (bndrs, rhss) = unzip pairs
691 tcIfaceExpr (IfaceCast expr co) = do
692 expr' <- tcIfaceExpr expr
693 co' <- tcIfaceType co
694 returnM (Cast expr' co')
696 tcIfaceExpr (IfaceNote note expr)
697 = tcIfaceExpr expr `thenM` \ expr' ->
699 IfaceInlineMe -> returnM (Note InlineMe expr')
700 IfaceSCC cc -> returnM (Note (SCC cc) expr')
701 IfaceCoreNote n -> returnM (Note (CoreNote n) expr')
703 -------------------------
704 tcIfaceAlt _ (IfaceDefault, names, rhs)
705 = ASSERT( null names )
706 tcIfaceExpr rhs `thenM` \ rhs' ->
707 returnM (DEFAULT, [], rhs')
709 tcIfaceAlt _ (IfaceLitAlt lit, names, rhs)
710 = ASSERT( null names )
711 tcIfaceExpr rhs `thenM` \ rhs' ->
712 returnM (LitAlt lit, [], rhs')
714 -- A case alternative is made quite a bit more complicated
715 -- by the fact that we omit type annotations because we can
716 -- work them out. True enough, but its not that easy!
717 tcIfaceAlt (tycon, inst_tys) (IfaceDataAlt data_occ, arg_strs, rhs)
718 = do { con <- tcIfaceDataCon data_occ
719 ; ASSERT2( con `elem` tyConDataCons tycon,
720 ppr con $$ ppr tycon $$ ppr (tyConDataCons tycon) )
721 tcIfaceDataAlt con inst_tys arg_strs rhs }
723 tcIfaceAlt (tycon, inst_tys) (IfaceTupleAlt boxity, arg_occs, rhs)
724 = ASSERT( isTupleTyCon tycon )
725 do { let [data_con] = tyConDataCons tycon
726 ; tcIfaceDataAlt data_con inst_tys arg_occs rhs }
728 tcIfaceDataAlt con inst_tys arg_strs rhs
729 = do { us <- newUniqueSupply
730 ; let uniqs = uniqsFromSupply us
731 ; let (ex_tvs, co_tvs, arg_ids)
732 = dataConRepFSInstPat arg_strs uniqs con inst_tys
733 all_tvs = ex_tvs ++ co_tvs
735 ; rhs' <- extendIfaceTyVarEnv all_tvs $
736 extendIfaceIdEnv arg_ids $
738 ; return (DataAlt con, all_tvs ++ arg_ids, rhs') }
743 tcExtCoreBindings :: [IfaceBinding] -> IfL [CoreBind] -- Used for external core
744 tcExtCoreBindings [] = return []
745 tcExtCoreBindings (b:bs) = do_one b (tcExtCoreBindings bs)
747 do_one :: IfaceBinding -> IfL [CoreBind] -> IfL [CoreBind]
748 do_one (IfaceNonRec bndr rhs) thing_inside
749 = do { rhs' <- tcIfaceExpr rhs
750 ; bndr' <- newExtCoreBndr bndr
751 ; extendIfaceIdEnv [bndr'] $ do
752 { core_binds <- thing_inside
753 ; return (NonRec bndr' rhs' : core_binds) }}
755 do_one (IfaceRec pairs) thing_inside
756 = do { bndrs' <- mappM newExtCoreBndr bndrs
757 ; extendIfaceIdEnv bndrs' $ do
758 { rhss' <- mappM tcIfaceExpr rhss
759 ; core_binds <- thing_inside
760 ; return (Rec (bndrs' `zip` rhss') : core_binds) }}
762 (bndrs,rhss) = unzip pairs
766 %************************************************************************
770 %************************************************************************
773 tcIdInfo :: Bool -> Name -> Type -> IfaceIdInfo -> IfL IdInfo
774 tcIdInfo ignore_prags name ty info
775 | ignore_prags = return vanillaIdInfo
776 | otherwise = case info of
777 NoInfo -> return vanillaIdInfo
778 HasInfo info -> foldlM tcPrag init_info info
780 -- Set the CgInfo to something sensible but uninformative before
781 -- we start; default assumption is that it has CAFs
782 init_info = vanillaIdInfo
784 tcPrag info HsNoCafRefs = returnM (info `setCafInfo` NoCafRefs)
785 tcPrag info (HsArity arity) = returnM (info `setArityInfo` arity)
786 tcPrag info (HsStrictness str) = returnM (info `setAllStrictnessInfo` Just str)
788 -- The next two are lazy, so they don't transitively suck stuff in
789 tcPrag info (HsWorker nm arity) = tcWorkerInfo ty info nm arity
790 tcPrag info (HsInline inline_prag) = returnM (info `setInlinePragInfo` inline_prag)
791 tcPrag info (HsUnfold expr)
792 = tcPragExpr name expr `thenM` \ maybe_expr' ->
794 -- maybe_expr' doesn't get looked at if the unfolding
795 -- is never inspected; so the typecheck doesn't even happen
796 unfold_info = case maybe_expr' of
797 Nothing -> noUnfolding
798 Just expr' -> mkTopUnfolding expr'
800 returnM (info `setUnfoldingInfoLazily` unfold_info)
804 tcWorkerInfo ty info wkr arity
805 = do { mb_wkr_id <- forkM_maybe doc (tcIfaceExtId wkr)
807 -- We return without testing maybe_wkr_id, but as soon as info is
808 -- looked at we will test it. That's ok, because its outside the
809 -- knot; and there seems no big reason to further defer the
810 -- tcIfaceId lookup. (Contrast with tcPragExpr, where postponing walking
811 -- over the unfolding until it's actually used does seem worth while.)
812 ; us <- newUniqueSupply
814 ; returnM (case mb_wkr_id of
816 Just wkr_id -> add_wkr_info us wkr_id info) }
818 doc = text "Worker for" <+> ppr wkr
819 add_wkr_info us wkr_id info
820 = info `setUnfoldingInfoLazily` mk_unfolding us wkr_id
821 `setWorkerInfo` HasWorker wkr_id arity
823 mk_unfolding us wkr_id = mkTopUnfolding (initUs_ us (mkWrapper ty strict_sig) wkr_id)
825 -- We are relying here on strictness info always appearing
826 -- before worker info, fingers crossed ....
827 strict_sig = case newStrictnessInfo info of
829 Nothing -> pprPanic "Worker info but no strictness for" (ppr wkr)
832 For unfoldings we try to do the job lazily, so that we never type check
833 an unfolding that isn't going to be looked at.
836 tcPragExpr :: Name -> IfaceExpr -> IfL (Maybe CoreExpr)
839 tcIfaceExpr expr `thenM` \ core_expr' ->
841 -- Check for type consistency in the unfolding
842 ifOptM Opt_DoCoreLinting (
843 get_in_scope_ids `thenM` \ in_scope ->
844 case lintUnfolding noSrcLoc in_scope core_expr' of
845 Nothing -> returnM ()
846 Just fail_msg -> pprPanic "Iface Lint failure" (hang doc 2 fail_msg)
851 doc = text "Unfolding of" <+> ppr name
852 get_in_scope_ids -- Urgh; but just for linting
854 do { env <- getGblEnv
855 ; case if_rec_types env of {
856 Nothing -> return [] ;
857 Just (_, get_env) -> do
858 { type_env <- get_env
859 ; return (typeEnvIds type_env) }}}
864 %************************************************************************
866 Getting from Names to TyThings
868 %************************************************************************
871 tcIfaceGlobal :: Name -> IfL TyThing
873 | Just thing <- wiredInNameTyThing_maybe name
874 -- Wired-in things include TyCons, DataCons, and Ids
875 = do { ifCheckWiredInThing name; return thing }
877 = do { (eps,hpt) <- getEpsAndHpt
879 ; case lookupType dflags hpt (eps_PTE eps) name of {
880 Just thing -> return thing ;
884 ; case if_rec_types env of {
885 Just (mod, get_type_env)
886 | nameIsLocalOrFrom mod name
887 -> do -- It's defined in the module being compiled
888 { type_env <- setLclEnv () get_type_env -- yuk
889 ; case lookupNameEnv type_env name of
890 Just thing -> return thing
891 Nothing -> pprPanic "tcIfaceGlobal (local): not found:"
892 (ppr name $$ ppr type_env) }
896 { mb_thing <- importDecl name -- It's imported; go get it
898 Failed err -> failIfM err
899 Succeeded thing -> return thing
902 ifCheckWiredInThing :: Name -> IfL ()
903 -- Even though we are in an interface file, we want to make
904 -- sure the instances of a wired-in thing are loaded (imagine f :: Double -> Double)
905 -- Ditto want to ensure that RULES are loaded too
906 ifCheckWiredInThing name
907 = do { mod <- getIfModule
908 -- Check whether we are typechecking the interface for this
909 -- very module. E.g when compiling the base library in --make mode
910 -- we may typecheck GHC.Base.hi. At that point, GHC.Base is not in
911 -- the HPT, so without the test we'll demand-load it into the PIT!
912 -- C.f. the same test in checkWiredInTyCon above
913 ; unless (mod == nameModule name)
914 (loadWiredInHomeIface name) }
916 tcIfaceTyCon :: IfaceTyCon -> IfL TyCon
917 tcIfaceTyCon IfaceIntTc = tcWiredInTyCon intTyCon
918 tcIfaceTyCon IfaceBoolTc = tcWiredInTyCon boolTyCon
919 tcIfaceTyCon IfaceCharTc = tcWiredInTyCon charTyCon
920 tcIfaceTyCon IfaceListTc = tcWiredInTyCon listTyCon
921 tcIfaceTyCon IfacePArrTc = tcWiredInTyCon parrTyCon
922 tcIfaceTyCon (IfaceTupTc bx ar) = tcWiredInTyCon (tupleTyCon bx ar)
923 tcIfaceTyCon (IfaceTc name) = do { thing <- tcIfaceGlobal name
924 ; return (check_tc (tyThingTyCon thing)) }
927 check_tc tc = case toIfaceTyCon tc of
929 other -> pprTrace "check_tc" (ppr tc) tc
933 -- we should be okay just returning Kind constructors without extra loading
934 tcIfaceTyCon IfaceLiftedTypeKindTc = return liftedTypeKindTyCon
935 tcIfaceTyCon IfaceOpenTypeKindTc = return openTypeKindTyCon
936 tcIfaceTyCon IfaceUnliftedTypeKindTc = return unliftedTypeKindTyCon
937 tcIfaceTyCon IfaceArgTypeKindTc = return argTypeKindTyCon
938 tcIfaceTyCon IfaceUbxTupleKindTc = return ubxTupleKindTyCon
940 -- Even though we are in an interface file, we want to make
941 -- sure the instances and RULES of this tycon are loaded
942 -- Imagine: f :: Double -> Double
943 tcWiredInTyCon :: TyCon -> IfL TyCon
944 tcWiredInTyCon tc = do { ifCheckWiredInThing (tyConName tc)
947 tcIfaceClass :: Name -> IfL Class
948 tcIfaceClass name = do { thing <- tcIfaceGlobal name
949 ; return (tyThingClass thing) }
951 tcIfaceDataCon :: Name -> IfL DataCon
952 tcIfaceDataCon name = do { thing <- tcIfaceGlobal name
954 ADataCon dc -> return dc
955 other -> pprPanic "tcIfaceExtDC" (ppr name$$ ppr thing) }
957 tcIfaceExtId :: Name -> IfL Id
958 tcIfaceExtId name = do { thing <- tcIfaceGlobal name
961 other -> pprPanic "tcIfaceExtId" (ppr name$$ ppr thing) }
964 %************************************************************************
968 %************************************************************************
971 bindIfaceBndr :: IfaceBndr -> (CoreBndr -> IfL a) -> IfL a
972 bindIfaceBndr (IfaceIdBndr (fs, ty)) thing_inside
973 = do { name <- newIfaceName (mkVarOccFS fs)
974 ; ty' <- tcIfaceType ty
975 ; let id = mkLocalId name ty'
976 ; extendIfaceIdEnv [id] (thing_inside id) }
977 bindIfaceBndr (IfaceTvBndr bndr) thing_inside
978 = bindIfaceTyVar bndr thing_inside
980 bindIfaceBndrs :: [IfaceBndr] -> ([CoreBndr] -> IfL a) -> IfL a
981 bindIfaceBndrs [] thing_inside = thing_inside []
982 bindIfaceBndrs (b:bs) thing_inside
983 = bindIfaceBndr b $ \ b' ->
984 bindIfaceBndrs bs $ \ bs' ->
985 thing_inside (b':bs')
987 -----------------------
988 tcIfaceLetBndr (IfLetBndr fs ty info)
989 = do { name <- newIfaceName (mkVarOccFS fs)
990 ; ty' <- tcIfaceType ty
992 NoInfo -> return (mkLocalId name ty')
993 HasInfo i -> return (mkLocalIdWithInfo name ty' (tc_info i)) }
995 -- Similar to tcIdInfo, but much simpler
996 tc_info [] = vanillaIdInfo
997 tc_info (HsInline p : i) = tc_info i `setInlinePragInfo` p
998 tc_info (HsArity a : i) = tc_info i `setArityInfo` a
999 tc_info (HsStrictness s : i) = tc_info i `setAllStrictnessInfo` Just s
1000 tc_info (other : i) = pprTrace "tcIfaceLetBndr: discarding unexpected IdInfo"
1001 (ppr other) (tc_info i)
1003 -----------------------
1004 newExtCoreBndr :: IfaceLetBndr -> IfL Id
1005 newExtCoreBndr (IfLetBndr var ty _) -- Ignoring IdInfo for now
1006 = do { mod <- getIfModule
1007 ; name <- newGlobalBinder mod (mkVarOccFS var) noSrcLoc
1008 ; ty' <- tcIfaceType ty
1009 ; return (mkLocalId name ty') }
1011 -----------------------
1012 bindIfaceTyVar :: IfaceTvBndr -> (TyVar -> IfL a) -> IfL a
1013 bindIfaceTyVar (occ,kind) thing_inside
1014 = do { name <- newIfaceName (mkTyVarOcc occ)
1015 ; tyvar <- mk_iface_tyvar name kind
1016 ; extendIfaceTyVarEnv [tyvar] (thing_inside tyvar) }
1018 bindIfaceTyVars :: [IfaceTvBndr] -> ([TyVar] -> IfL a) -> IfL a
1019 bindIfaceTyVars bndrs thing_inside
1020 = do { names <- newIfaceNames (map mkTyVarOcc occs)
1021 ; tyvars <- TcRnMonad.zipWithM mk_iface_tyvar names kinds
1022 ; extendIfaceTyVarEnv tyvars (thing_inside tyvars) }
1024 (occs,kinds) = unzip bndrs
1026 mk_iface_tyvar :: Name -> IfaceKind -> IfL TyVar
1027 mk_iface_tyvar name ifKind
1028 = do { kind <- tcIfaceType ifKind
1029 ; if isCoercionKind kind then
1030 return (Var.mkCoVar name kind)
1032 return (Var.mkTyVar name kind) }