2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[TcIfaceSig]{Type checking of type signatures in interface files}
8 tcImportDecl, checkWiredInTyCon, tcHiBootIface, typecheckIface,
9 tcIfaceDecl, tcIfaceInst, tcIfaceRule, tcIfaceGlobal,
13 #include "HsVersions.h"
16 import LoadIface ( loadInterface, loadWiredInHomeIface,
17 loadDecls, findAndReadIface )
18 import IfaceEnv ( lookupIfaceTop, lookupIfaceExt, newGlobalBinder,
19 extendIfaceIdEnv, extendIfaceTyVarEnv, newIPName,
20 tcIfaceTyVar, tcIfaceLclId, lookupIfaceTc, refineIfaceIdEnv,
21 newIfaceName, newIfaceNames, ifaceExportNames )
22 import BuildTyCl ( buildSynTyCon, buildAlgTyCon, buildDataCon, buildClass,
23 mkAbstractTyConRhs, mkDataTyConRhs, mkNewTyConRhs )
25 import Type ( liftedTypeKind, splitTyConApp, mkTyConApp,
26 mkTyVarTys, ThetaType )
27 import TypeRep ( Type(..), PredType(..) )
28 import TyCon ( TyCon, tyConName )
29 import HscTypes ( ExternalPackageState(..),
30 TyThing(..), tyThingClass, tyThingTyCon,
31 ModIface(..), ModDetails(..), HomeModInfo(..),
32 emptyModDetails, lookupTypeEnv, lookupType, typeEnvIds )
33 import InstEnv ( Instance(..), mkImportedInstance )
34 import Unify ( coreRefineTys )
36 import CoreUtils ( exprType )
38 import CoreLint ( lintUnfolding )
39 import WorkWrap ( mkWrapper )
40 import Id ( Id, mkVanillaGlobal, mkLocalId )
41 import MkId ( mkFCallId )
42 import IdInfo ( IdInfo, CafInfo(..), WorkerInfo(..),
43 setUnfoldingInfoLazily, setAllStrictnessInfo, setWorkerInfo,
44 setArityInfo, setInlinePragInfo, setCafInfo,
45 vanillaIdInfo, newStrictnessInfo )
46 import Class ( Class )
47 import TyCon ( tyConDataCons, isTupleTyCon, mkForeignTyCon )
48 import DataCon ( DataCon, dataConWorkId, dataConTyVars, dataConInstArgTys, isVanillaDataCon )
49 import TysWiredIn ( tupleCon, tupleTyCon, listTyCon, intTyCon, boolTyCon, charTyCon, parrTyCon )
50 import Var ( TyVar, mkTyVar, tyVarKind )
51 import Name ( Name, nameModule, nameIsLocalOrFrom, isWiredInName,
52 wiredInNameTyThing_maybe, nameParent )
54 import OccName ( OccName, mkVarOccFS, mkTyVarOcc )
55 import FastString ( FastString )
56 import Module ( Module, moduleName )
57 import UniqFM ( lookupUFM )
58 import UniqSupply ( initUs_ )
60 import ErrUtils ( Message )
61 import Maybes ( MaybeErr(..) )
62 import SrcLoc ( noSrcLoc )
63 import Util ( zipWithEqual, equalLength, splitAtList )
64 import DynFlags ( DynFlag(..), isOneShot )
73 An IfaceDecl is populated with RdrNames, and these are not renamed to
74 Names before typechecking, because there should be no scope errors etc.
76 -- For (b) consider: f = $(...h....)
77 -- where h is imported, and calls f via an hi-boot file.
78 -- This is bad! But it is not seen as a staging error, because h
79 -- is indeed imported. We don't want the type-checker to black-hole
80 -- when simplifying and compiling the splice!
82 -- Simple solution: discard any unfolding that mentions a variable
83 -- bound in this module (and hence not yet processed).
84 -- The discarding happens when forkM finds a type error.
86 %************************************************************************
88 %* tcImportDecl is the key function for "faulting in" *
91 %************************************************************************
93 The main idea is this. We are chugging along type-checking source code, and
94 find a reference to GHC.Base.map. We call tcLookupGlobal, which doesn't find
95 it in the EPS type envt. So it
97 2 gets the decl for GHC.Base.map
98 3 typechecks it via tcIfaceDecl
99 4 and adds it to the type env in the EPS
101 Note that DURING STEP 4, we may find that map's type mentions a type
102 constructor that also
104 Notice that for imported things we read the current version from the EPS
105 mutable variable. This is important in situations like
107 where the code that e1 expands to might import some defns that
108 also turn out to be needed by the code that e2 expands to.
111 tcImportDecl :: Name -> TcM TyThing
112 -- Entry point for *source-code* uses of importDecl
114 | Just thing <- wiredInNameTyThing_maybe name
115 = do { initIfaceTcRn (loadWiredInHomeIface name)
118 = do { traceIf (text "tcImportDecl" <+> ppr name)
119 ; mb_thing <- initIfaceTcRn (importDecl name)
121 Succeeded thing -> return thing
122 Failed err -> failWithTc err }
124 checkWiredInTyCon :: TyCon -> TcM ()
125 -- Ensure that the home module of the TyCon (and hence its instances)
126 -- are loaded. It might not be a wired-in tycon (see the calls in TcUnify),
127 -- in which case this is a no-op.
129 | not (isWiredInName tc_name)
132 = do { mod <- getModule
133 ; if nameIsLocalOrFrom mod tc_name then
134 -- Don't look for (non-existent) Float.hi when
135 -- compiling Float.lhs, which mentions Float of course
137 else -- A bit yukky to call initIfaceTcRn here
138 initIfaceTcRn (loadWiredInHomeIface tc_name)
141 tc_name = tyConName tc
143 importDecl :: Name -> IfM lcl (MaybeErr Message TyThing)
144 -- Get the TyThing for this Name from an interface file
145 -- It's not a wired-in thing -- the caller caught that
147 = ASSERT( not (isWiredInName name) )
150 -- Load the interface, which should populate the PTE
151 ; mb_iface <- loadInterface nd_doc (nameModule name) ImportBySystem
153 Failed err_msg -> return (Failed err_msg) ;
154 Succeeded iface -> do
156 -- Now look it up again; this time we should find it
158 ; case lookupTypeEnv (eps_PTE eps) name of
159 Just thing -> return (Succeeded thing)
160 Nothing -> return (Failed not_found_msg)
163 nd_doc = ptext SLIT("Need decl for") <+> ppr name
164 not_found_msg = hang (ptext SLIT("Can't find interface-file declaration for") <+> ppr (nameParent name))
165 2 (vcat [ptext SLIT("Probable cause: bug in .hi-boot file, or inconsistent .hi file"),
166 ptext SLIT("Use -ddump-if-trace to get an idea of which file caused the error")])
169 %************************************************************************
171 Type-checking a complete interface
173 %************************************************************************
175 Suppose we discover we don't need to recompile. Then we must type
176 check the old interface file. This is a bit different to the
177 incremental type checking we do as we suck in interface files. Instead
178 we do things similarly as when we are typechecking source decls: we
179 bring into scope the type envt for the interface all at once, using a
180 knot. Remember, the decls aren't necessarily in dependency order --
181 and even if they were, the type decls might be mutually recursive.
184 typecheckIface :: ModIface -- Get the decls from here
185 -> TcRnIf gbl lcl ModDetails
187 = initIfaceTc iface $ \ tc_env_var -> do
188 -- The tc_env_var is freshly allocated, private to
189 -- type-checking this particular interface
190 { -- Get the right set of decls and rules. If we are compiling without -O
191 -- we discard pragmas before typechecking, so that we don't "see"
192 -- information that we shouldn't. From a versioning point of view
193 -- It's not actually *wrong* to do so, but in fact GHCi is unable
194 -- to handle unboxed tuples, so it must not see unfoldings.
195 ignore_prags <- doptM Opt_IgnoreInterfacePragmas
197 -- Load & typecheck the decls
198 ; decl_things <- loadDecls ignore_prags (mi_decls iface)
200 ; let type_env = mkNameEnv decl_things
201 ; writeMutVar tc_env_var type_env
203 -- Now do those rules and instances
204 ; let { rules | ignore_prags = []
205 | otherwise = mi_rules iface
206 ; dfuns = mi_insts iface
208 ; dfuns <- mapM tcIfaceInst dfuns
209 ; rules <- mapM tcIfaceRule rules
212 ; exports <- ifaceExportNames (mi_exports iface)
215 ; return (ModDetails { md_types = type_env,
218 md_exports = exports })
223 %************************************************************************
225 Type and class declarations
227 %************************************************************************
230 tcHiBootIface :: Module -> TcRn ModDetails
231 -- Load the hi-boot iface for the module being compiled,
232 -- if it indeed exists in the transitive closure of imports
233 -- Return the ModDetails, empty if no hi-boot iface
235 = do { traceIf (text "loadHiBootInterface" <+> ppr mod)
238 ; if not (isOneShot mode)
239 -- In --make and interactive mode, if this module has an hs-boot file
240 -- we'll have compiled it already, and it'll be in the HPT
242 -- We check wheher the interface is a *boot* interface.
243 -- It can happen (when using GHC from Visual Studio) that we
244 -- compile a module in TypecheckOnly mode, with a stable,
245 -- fully-populated HPT. In that case the boot interface isn't there
246 -- (it's been replaced by the mother module) so we can't check it.
247 -- And that's fine, because if M's ModInfo is in the HPT, then
248 -- it's been compiled once, and we don't need to check the boot iface
249 then do { hpt <- getHpt
250 ; case lookupUFM hpt (moduleName mod) of
251 Just info | mi_boot (hm_iface info)
252 -> return (hm_details info)
253 other -> return emptyModDetails }
256 -- OK, so we're in one-shot mode.
257 -- In that case, we're read all the direct imports by now,
258 -- so eps_is_boot will record if any of our imports mention us by
259 -- way of hi-boot file
261 ; case lookupUFM (eps_is_boot eps) (moduleName mod) of {
262 Nothing -> return emptyModDetails ; -- The typical case
264 Just (_, False) -> failWithTc moduleLoop ;
265 -- Someone below us imported us!
266 -- This is a loop with no hi-boot in the way
268 Just (_mod, True) -> -- There's a hi-boot interface below us
270 do { read_result <- findAndReadIface
274 ; case read_result of
275 Failed err -> failWithTc (elaborate err)
276 Succeeded (iface, _path) -> typecheckIface iface
279 need = ptext SLIT("Need the hi-boot interface for") <+> ppr mod
280 <+> ptext SLIT("to compare against the Real Thing")
282 moduleLoop = ptext SLIT("Circular imports: module") <+> quotes (ppr mod)
283 <+> ptext SLIT("depends on itself")
285 elaborate err = hang (ptext SLIT("Could not find hi-boot interface for") <+>
286 quotes (ppr mod) <> colon) 4 err
290 %************************************************************************
292 Type and class declarations
294 %************************************************************************
296 When typechecking a data type decl, we *lazily* (via forkM) typecheck
297 the constructor argument types. This is in the hope that we may never
298 poke on those argument types, and hence may never need to load the
299 interface files for types mentioned in the arg types.
302 data Foo.S = MkS Baz.T
303 Mabye we can get away without even loading the interface for Baz!
305 This is not just a performance thing. Suppose we have
306 data Foo.S = MkS Baz.T
307 data Baz.T = MkT Foo.S
308 (in different interface files, of course).
309 Now, first we load and typecheck Foo.S, and add it to the type envt.
310 If we do explore MkS's argument, we'll load and typecheck Baz.T.
311 If we explore MkT's argument we'll find Foo.S already in the envt.
313 If we typechecked constructor args eagerly, when loading Foo.S we'd try to
314 typecheck the type Baz.T. So we'd fault in Baz.T... and then need Foo.S...
315 which isn't done yet.
317 All very cunning. However, there is a rather subtle gotcha which bit
318 me when developing this stuff. When we typecheck the decl for S, we
319 extend the type envt with S, MkS, and all its implicit Ids. Suppose
320 (a bug, but it happened) that the list of implicit Ids depended in
321 turn on the constructor arg types. Then the following sequence of
323 * we build a thunk <t> for the constructor arg tys
324 * we build a thunk for the extended type environment (depends on <t>)
325 * we write the extended type envt into the global EPS mutvar
327 Now we look something up in the type envt
329 * which reads the global type envt out of the global EPS mutvar
330 * but that depends in turn on <t>
332 It's subtle, because, it'd work fine if we typechecked the constructor args
333 eagerly -- they don't need the extended type envt. They just get the extended
334 type envt by accident, because they look at it later.
336 What this means is that the implicitTyThings MUST NOT DEPEND on any of
341 tcIfaceDecl :: IfaceDecl -> IfL TyThing
343 tcIfaceDecl (IfaceId {ifName = occ_name, ifType = iface_type, ifIdInfo = info})
344 = do { name <- lookupIfaceTop occ_name
345 ; ty <- tcIfaceType iface_type
346 ; info <- tcIdInfo name ty info
347 ; return (AnId (mkVanillaGlobal name ty info)) }
349 tcIfaceDecl (IfaceData {ifName = occ_name,
353 ifVrcs = arg_vrcs, ifRec = is_rec,
354 ifGeneric = want_generic })
355 = do { tc_name <- lookupIfaceTop occ_name
356 ; bindIfaceTyVars tv_bndrs $ \ tyvars -> do
358 { tycon <- fixM ( \ tycon -> do
359 { stupid_theta <- tcIfaceCtxt ctxt
360 ; cons <- tcIfaceDataCons tycon tyvars rdr_cons
361 ; buildAlgTyCon tc_name tyvars stupid_theta
362 cons arg_vrcs is_rec want_generic
364 ; traceIf (text "tcIfaceDecl4" <+> ppr tycon)
365 ; return (ATyCon tycon)
368 tcIfaceDecl (IfaceSyn {ifName = occ_name, ifTyVars = tv_bndrs,
369 ifSynRhs = rdr_rhs_ty, ifVrcs = arg_vrcs})
370 = bindIfaceTyVars tv_bndrs $ \ tyvars -> do
371 { tc_name <- lookupIfaceTop occ_name
372 ; rhs_ty <- tcIfaceType rdr_rhs_ty
373 ; return (ATyCon (buildSynTyCon tc_name tyvars rhs_ty arg_vrcs))
376 tcIfaceDecl (IfaceClass {ifCtxt = rdr_ctxt, ifName = occ_name, ifTyVars = tv_bndrs,
377 ifFDs = rdr_fds, ifSigs = rdr_sigs,
378 ifVrcs = tc_vrcs, ifRec = tc_isrec })
379 = bindIfaceTyVars tv_bndrs $ \ tyvars -> do
380 { cls_name <- lookupIfaceTop occ_name
381 ; ctxt <- tcIfaceCtxt rdr_ctxt
382 ; sigs <- mappM tc_sig rdr_sigs
383 ; fds <- mappM tc_fd rdr_fds
384 ; cls <- buildClass cls_name tyvars ctxt fds sigs tc_isrec tc_vrcs
385 ; return (AClass cls) }
387 tc_sig (IfaceClassOp occ dm rdr_ty)
388 = do { op_name <- lookupIfaceTop occ
389 ; op_ty <- forkM (mk_doc op_name rdr_ty) (tcIfaceType rdr_ty)
390 -- Must be done lazily for just the same reason as the
391 -- context of a data decl: the type sig might mention the
392 -- class being defined
393 ; return (op_name, dm, op_ty) }
395 mk_doc op_name op_ty = ptext SLIT("Class op") <+> sep [ppr op_name, ppr op_ty]
397 tc_fd (tvs1, tvs2) = do { tvs1' <- mappM tcIfaceTyVar tvs1
398 ; tvs2' <- mappM tcIfaceTyVar tvs2
399 ; return (tvs1', tvs2') }
401 tcIfaceDecl (IfaceForeign {ifName = rdr_name, ifExtName = ext_name})
402 = do { name <- lookupIfaceTop rdr_name
403 ; return (ATyCon (mkForeignTyCon name ext_name
404 liftedTypeKind 0 [])) }
406 tcIfaceDataCons tycon tc_tyvars if_cons
408 IfAbstractTyCon -> return mkAbstractTyConRhs
409 IfDataTyCon cons -> do { data_cons <- mappM tc_con_decl cons
410 ; return (mkDataTyConRhs data_cons) }
411 IfNewTyCon con -> do { data_con <- tc_con_decl con
412 ; return (mkNewTyConRhs tycon data_con) }
414 tc_con_decl (IfVanillaCon { ifConOcc = occ, ifConInfix = is_infix, ifConArgTys = args,
415 ifConStricts = stricts, ifConFields = field_lbls})
416 = do { name <- lookupIfaceTop occ
417 -- Read the argument types, but lazily to avoid faulting in
418 -- the component types unless they are really needed
419 ; arg_tys <- forkM (mk_doc name) (mappM tcIfaceType args)
420 ; lbl_names <- mappM lookupIfaceTop field_lbls
421 ; buildDataCon name is_infix True {- Vanilla -}
423 tc_tyvars [] arg_tys tycon
424 (mkTyVarTys tc_tyvars) -- Vanilla => we know result tys
427 tc_con_decl (IfGadtCon { ifConTyVars = con_tvs,
428 ifConOcc = occ, ifConCtxt = ctxt,
429 ifConArgTys = args, ifConResTys = ress,
430 ifConStricts = stricts})
431 = bindIfaceTyVars con_tvs $ \ con_tyvars -> do
432 { name <- lookupIfaceTop occ
433 ; theta <- tcIfaceCtxt ctxt -- Laziness seems not worth the bother here
434 -- At one stage I thought that this context checking *had*
435 -- to be lazy, because of possible mutual recursion between the
436 -- type and the classe:
438 -- class Real a where { toRat :: a -> Ratio Integer }
439 -- data (Real a) => Ratio a = ...
440 -- But now I think that the laziness in checking class ops breaks
441 -- the loop, so no laziness needed
443 -- Read the argument types, but lazily to avoid faulting in
444 -- the component types unless they are really needed
445 ; arg_tys <- forkM (mk_doc name) (mappM tcIfaceType args)
446 ; res_tys <- forkM (mk_doc name) (mappM tcIfaceType ress)
448 ; buildDataCon name False {- Not infix -} False {- Not vanilla -}
449 stricts [{- No fields -}]
451 arg_tys tycon res_tys
453 mk_doc con_name = ptext SLIT("Constructor") <+> ppr con_name
457 %************************************************************************
461 %************************************************************************
464 tcIfaceInst :: IfaceInst -> IfL Instance
465 tcIfaceInst (IfaceInst { ifDFun = dfun_occ, ifOFlag = oflag,
466 ifInstCls = cls, ifInstTys = mb_tcs,
468 = do { dfun <- forkM (ptext SLIT("Dict fun") <+> ppr dfun_occ) $
469 tcIfaceExtId (LocalTop dfun_occ)
470 ; cls' <- lookupIfaceExt cls
471 ; mb_tcs' <- mapM do_tc mb_tcs
472 ; return (mkImportedInstance cls' mb_tcs' orph dfun oflag) }
474 do_tc Nothing = return Nothing
475 do_tc (Just tc) = do { tc' <- lookupIfaceTc tc; return (Just tc') }
479 %************************************************************************
483 %************************************************************************
485 We move a IfaceRule from eps_rules to eps_rule_base when all its LHS free vars
486 are in the type environment. However, remember that typechecking a Rule may
487 (as a side effect) augment the type envt, and so we may need to iterate the process.
490 tcIfaceRule :: IfaceRule -> IfL CoreRule
491 tcIfaceRule (IfaceRule {ifRuleName = name, ifActivation = act, ifRuleBndrs = bndrs,
492 ifRuleHead = fn, ifRuleArgs = args, ifRuleRhs = rhs,
494 = do { fn' <- lookupIfaceExt fn
495 ; ~(bndrs', args', rhs') <-
496 -- Typecheck the payload lazily, in the hope it'll never be looked at
497 forkM (ptext SLIT("Rule") <+> ftext name) $
498 bindIfaceBndrs bndrs $ \ bndrs' ->
499 do { args' <- mappM tcIfaceExpr args
500 ; rhs' <- tcIfaceExpr rhs
501 ; return (bndrs', args', rhs') }
502 ; mb_tcs <- mapM ifTopFreeName args
503 ; returnM (Rule { ru_name = name, ru_fn = fn', ru_act = act,
504 ru_bndrs = bndrs', ru_args = args',
505 ru_rhs = rhs', ru_orph = orph,
507 ru_local = isLocalIfaceExtName fn }) }
509 -- This function *must* mirror exactly what Rules.topFreeName does
510 -- We could have stored the ru_rough field in the iface file
511 -- but that would be redundant, I think.
512 -- The only wrinkle is that we must not be deceived by
513 -- type syononyms at the top of a type arg. Since
514 -- we can't tell at this point, we are careful not
515 -- to write them out in coreRuleToIfaceRule
516 ifTopFreeName :: IfaceExpr -> IfL (Maybe Name)
517 ifTopFreeName (IfaceType (IfaceTyConApp tc _ ))
518 = do { n <- lookupIfaceTc tc
520 ifTopFreeName (IfaceApp f a) = ifTopFreeName f
521 ifTopFreeName (IfaceExt ext) = do { n <- lookupIfaceExt ext
523 ifTopFreeName other = return Nothing
527 %************************************************************************
531 %************************************************************************
534 tcIfaceType :: IfaceType -> IfL Type
535 tcIfaceType (IfaceTyVar n) = do { tv <- tcIfaceTyVar n; return (TyVarTy tv) }
536 tcIfaceType (IfaceAppTy t1 t2) = do { t1' <- tcIfaceType t1; t2' <- tcIfaceType t2; return (AppTy t1' t2') }
537 tcIfaceType (IfaceFunTy t1 t2) = do { t1' <- tcIfaceType t1; t2' <- tcIfaceType t2; return (FunTy t1' t2') }
538 tcIfaceType (IfaceTyConApp tc ts) = do { tc' <- tcIfaceTyCon tc; ts' <- tcIfaceTypes ts; return (mkTyConApp tc' ts') }
539 tcIfaceType (IfaceForAllTy tv t) = bindIfaceTyVar tv $ \ tv' -> do { t' <- tcIfaceType t; return (ForAllTy tv' t') }
540 tcIfaceType (IfacePredTy st) = do { st' <- tcIfacePredType st; return (PredTy st') }
542 tcIfaceTypes tys = mapM tcIfaceType tys
544 -----------------------------------------
545 tcIfacePredType :: IfacePredType -> IfL PredType
546 tcIfacePredType (IfaceClassP cls ts) = do { cls' <- tcIfaceClass cls; ts' <- tcIfaceTypes ts; return (ClassP cls' ts') }
547 tcIfacePredType (IfaceIParam ip t) = do { ip' <- newIPName ip; t' <- tcIfaceType t; return (IParam ip' t') }
549 -----------------------------------------
550 tcIfaceCtxt :: IfaceContext -> IfL ThetaType
551 tcIfaceCtxt sts = mappM tcIfacePredType sts
555 %************************************************************************
559 %************************************************************************
562 tcIfaceExpr :: IfaceExpr -> IfL CoreExpr
563 tcIfaceExpr (IfaceType ty)
564 = tcIfaceType ty `thenM` \ ty' ->
567 tcIfaceExpr (IfaceLcl name)
568 = tcIfaceLclId name `thenM` \ id ->
571 tcIfaceExpr (IfaceExt gbl)
572 = tcIfaceExtId gbl `thenM` \ id ->
575 tcIfaceExpr (IfaceLit lit)
578 tcIfaceExpr (IfaceFCall cc ty)
579 = tcIfaceType ty `thenM` \ ty' ->
580 newUnique `thenM` \ u ->
581 returnM (Var (mkFCallId u cc ty'))
583 tcIfaceExpr (IfaceTuple boxity args)
584 = mappM tcIfaceExpr args `thenM` \ args' ->
586 -- Put the missing type arguments back in
587 con_args = map (Type . exprType) args' ++ args'
589 returnM (mkApps (Var con_id) con_args)
592 con_id = dataConWorkId (tupleCon boxity arity)
595 tcIfaceExpr (IfaceLam bndr body)
596 = bindIfaceBndr bndr $ \ bndr' ->
597 tcIfaceExpr body `thenM` \ body' ->
598 returnM (Lam bndr' body')
600 tcIfaceExpr (IfaceApp fun arg)
601 = tcIfaceExpr fun `thenM` \ fun' ->
602 tcIfaceExpr arg `thenM` \ arg' ->
603 returnM (App fun' arg')
605 tcIfaceExpr (IfaceCase scrut case_bndr ty alts)
606 = tcIfaceExpr scrut `thenM` \ scrut' ->
607 newIfaceName (mkVarOccFS case_bndr) `thenM` \ case_bndr_name ->
609 scrut_ty = exprType scrut'
610 case_bndr' = mkLocalId case_bndr_name scrut_ty
611 tc_app = splitTyConApp scrut_ty
612 -- NB: Won't always succeed (polymoprhic case)
613 -- but won't be demanded in those cases
614 -- NB: not tcSplitTyConApp; we are looking at Core here
615 -- look through non-rec newtypes to find the tycon that
616 -- corresponds to the datacon in this case alternative
618 extendIfaceIdEnv [case_bndr'] $
619 mappM (tcIfaceAlt tc_app) alts `thenM` \ alts' ->
620 tcIfaceType ty `thenM` \ ty' ->
621 returnM (Case scrut' case_bndr' ty' alts')
623 tcIfaceExpr (IfaceLet (IfaceNonRec bndr rhs) body)
624 = tcIfaceExpr rhs `thenM` \ rhs' ->
625 bindIfaceId bndr $ \ bndr' ->
626 tcIfaceExpr body `thenM` \ body' ->
627 returnM (Let (NonRec bndr' rhs') body')
629 tcIfaceExpr (IfaceLet (IfaceRec pairs) body)
630 = bindIfaceIds bndrs $ \ bndrs' ->
631 mappM tcIfaceExpr rhss `thenM` \ rhss' ->
632 tcIfaceExpr body `thenM` \ body' ->
633 returnM (Let (Rec (bndrs' `zip` rhss')) body')
635 (bndrs, rhss) = unzip pairs
637 tcIfaceExpr (IfaceNote note expr)
638 = tcIfaceExpr expr `thenM` \ expr' ->
640 IfaceCoerce to_ty -> tcIfaceType to_ty `thenM` \ to_ty' ->
641 returnM (Note (Coerce to_ty'
642 (exprType expr')) expr')
643 IfaceInlineMe -> returnM (Note InlineMe expr')
644 IfaceSCC cc -> returnM (Note (SCC cc) expr')
645 IfaceCoreNote n -> returnM (Note (CoreNote n) expr')
647 -------------------------
648 tcIfaceAlt _ (IfaceDefault, names, rhs)
649 = ASSERT( null names )
650 tcIfaceExpr rhs `thenM` \ rhs' ->
651 returnM (DEFAULT, [], rhs')
653 tcIfaceAlt _ (IfaceLitAlt lit, names, rhs)
654 = ASSERT( null names )
655 tcIfaceExpr rhs `thenM` \ rhs' ->
656 returnM (LitAlt lit, [], rhs')
658 -- A case alternative is made quite a bit more complicated
659 -- by the fact that we omit type annotations because we can
660 -- work them out. True enough, but its not that easy!
661 tcIfaceAlt (tycon, inst_tys) (IfaceDataAlt data_occ, arg_strs, rhs)
662 = do { let tycon_mod = nameModule (tyConName tycon)
663 ; con <- tcIfaceDataCon (ExtPkg tycon_mod data_occ)
664 ; ASSERT2( con `elem` tyConDataCons tycon,
665 ppr con $$ ppr tycon $$ ppr (tyConDataCons tycon) )
667 if isVanillaDataCon con then
668 tcVanillaAlt con inst_tys arg_strs rhs
671 let (tyvar_strs, id_strs) = splitAtList (dataConTyVars con) arg_strs
672 ; tyvar_names <- mapM (newIfaceName . mkTyVarOcc) tyvar_strs
673 ; id_names <- mapM (newIfaceName . mkVarOccFS) id_strs
674 ; let tyvars = [ mkTyVar name (tyVarKind tv)
675 | (name,tv) <- tyvar_names `zip` dataConTyVars con ]
676 arg_tys = dataConInstArgTys con (mkTyVarTys tyvars)
677 arg_ids = ASSERT2( equalLength id_names arg_tys,
678 ppr (con, tyvar_names++id_names, rhs) $$ ppr tyvars $$ ppr arg_tys )
679 zipWith mkLocalId id_names arg_tys
681 Just refine = coreRefineTys con tyvars (mkTyConApp tycon inst_tys)
683 ; rhs' <- extendIfaceTyVarEnv tyvars $
684 extendIfaceIdEnv arg_ids $
685 refineIfaceIdEnv refine $
686 -- You might think that we don't need to refine the envt here,
687 -- but we do: \(x::a) -> case y of
688 -- MkT -> case x of { True -> ... }
689 -- In the "case x" we need to know x's type, because we use that
690 -- to find which module to look for "True" in. Sigh.
692 ; return (DataAlt con, tyvars ++ arg_ids, rhs') }}
694 tcIfaceAlt (tycon, inst_tys) (IfaceTupleAlt boxity, arg_occs, rhs)
695 = ASSERT( isTupleTyCon tycon )
696 do { let [data_con] = tyConDataCons tycon
697 ; tcVanillaAlt data_con inst_tys arg_occs rhs }
699 tcVanillaAlt data_con inst_tys arg_strs rhs
700 = do { arg_names <- newIfaceNames (map mkVarOccFS arg_strs)
701 ; let arg_tys = dataConInstArgTys data_con inst_tys
702 ; let arg_ids = ASSERT2( equalLength arg_names arg_tys,
703 ppr data_con <+> ppr inst_tys <+> ppr arg_strs $$ ppr rhs )
704 zipWith mkLocalId arg_names arg_tys
705 ; rhs' <- extendIfaceIdEnv arg_ids (tcIfaceExpr rhs)
706 ; returnM (DataAlt data_con, arg_ids, rhs') }
711 tcExtCoreBindings :: [IfaceBinding] -> IfL [CoreBind] -- Used for external core
712 tcExtCoreBindings [] = return []
713 tcExtCoreBindings (b:bs) = do_one b (tcExtCoreBindings bs)
715 do_one :: IfaceBinding -> IfL [CoreBind] -> IfL [CoreBind]
716 do_one (IfaceNonRec bndr rhs) thing_inside
717 = do { rhs' <- tcIfaceExpr rhs
718 ; bndr' <- newExtCoreBndr bndr
719 ; extendIfaceIdEnv [bndr'] $ do
720 { core_binds <- thing_inside
721 ; return (NonRec bndr' rhs' : core_binds) }}
723 do_one (IfaceRec pairs) thing_inside
724 = do { bndrs' <- mappM newExtCoreBndr bndrs
725 ; extendIfaceIdEnv bndrs' $ do
726 { rhss' <- mappM tcIfaceExpr rhss
727 ; core_binds <- thing_inside
728 ; return (Rec (bndrs' `zip` rhss') : core_binds) }}
730 (bndrs,rhss) = unzip pairs
734 %************************************************************************
738 %************************************************************************
741 tcIdInfo :: Name -> Type -> IfaceIdInfo -> IfL IdInfo
742 tcIdInfo name ty NoInfo = return vanillaIdInfo
743 tcIdInfo name ty (HasInfo info) = foldlM tcPrag init_info info
745 -- Set the CgInfo to something sensible but uninformative before
746 -- we start; default assumption is that it has CAFs
747 init_info = vanillaIdInfo
749 tcPrag info HsNoCafRefs = returnM (info `setCafInfo` NoCafRefs)
750 tcPrag info (HsArity arity) = returnM (info `setArityInfo` arity)
751 tcPrag info (HsStrictness str) = returnM (info `setAllStrictnessInfo` Just str)
753 -- The next two are lazy, so they don't transitively suck stuff in
754 tcPrag info (HsWorker nm arity) = tcWorkerInfo ty info nm arity
755 tcPrag info (HsInline inline_prag) = returnM (info `setInlinePragInfo` inline_prag)
756 tcPrag info (HsUnfold expr)
757 = tcPragExpr name expr `thenM` \ maybe_expr' ->
759 -- maybe_expr' doesn't get looked at if the unfolding
760 -- is never inspected; so the typecheck doesn't even happen
761 unfold_info = case maybe_expr' of
762 Nothing -> noUnfolding
763 Just expr' -> mkTopUnfolding expr'
765 returnM (info `setUnfoldingInfoLazily` unfold_info)
769 tcWorkerInfo ty info wkr arity
770 = do { mb_wkr_id <- forkM_maybe doc (tcIfaceExtId wkr)
772 -- We return without testing maybe_wkr_id, but as soon as info is
773 -- looked at we will test it. That's ok, because its outside the
774 -- knot; and there seems no big reason to further defer the
775 -- tcIfaceId lookup. (Contrast with tcPragExpr, where postponing walking
776 -- over the unfolding until it's actually used does seem worth while.)
777 ; us <- newUniqueSupply
779 ; returnM (case mb_wkr_id of
781 Just wkr_id -> add_wkr_info us wkr_id info) }
783 doc = text "Worker for" <+> ppr wkr
784 add_wkr_info us wkr_id info
785 = info `setUnfoldingInfoLazily` mk_unfolding us wkr_id
786 `setWorkerInfo` HasWorker wkr_id arity
788 mk_unfolding us wkr_id = mkTopUnfolding (initUs_ us (mkWrapper ty strict_sig) wkr_id)
790 -- We are relying here on strictness info always appearing
791 -- before worker info, fingers crossed ....
792 strict_sig = case newStrictnessInfo info of
794 Nothing -> pprPanic "Worker info but no strictness for" (ppr wkr)
797 For unfoldings we try to do the job lazily, so that we never type check
798 an unfolding that isn't going to be looked at.
801 tcPragExpr :: Name -> IfaceExpr -> IfL (Maybe CoreExpr)
804 tcIfaceExpr expr `thenM` \ core_expr' ->
806 -- Check for type consistency in the unfolding
807 ifOptM Opt_DoCoreLinting (
808 get_in_scope_ids `thenM` \ in_scope ->
809 case lintUnfolding noSrcLoc in_scope core_expr' of
810 Nothing -> returnM ()
811 Just fail_msg -> pprPanic "Iface Lint failure" (doc <+> fail_msg)
816 doc = text "Unfolding of" <+> ppr name
817 get_in_scope_ids -- Urgh; but just for linting
819 do { env <- getGblEnv
820 ; case if_rec_types env of {
821 Nothing -> return [] ;
822 Just (_, get_env) -> do
823 { type_env <- get_env
824 ; return (typeEnvIds type_env) }}}
829 %************************************************************************
831 Getting from Names to TyThings
833 %************************************************************************
836 tcIfaceGlobal :: Name -> IfL TyThing
838 | Just thing <- wiredInNameTyThing_maybe name
839 -- Wired-in things include TyCons, DataCons, and Ids
840 = do { loadWiredInHomeIface name; return thing }
841 -- Even though we are in an interface file, we want to make
842 -- sure its instances are loaded (imagine f :: Double -> Double)
843 -- and its RULES are loaded too
845 = do { (eps,hpt) <- getEpsAndHpt
847 ; case lookupType dflags hpt (eps_PTE eps) name of {
848 Just thing -> return thing ;
852 ; case if_rec_types env of {
853 Just (mod, get_type_env)
854 | nameIsLocalOrFrom mod name
855 -> do -- It's defined in the module being compiled
856 { type_env <- setLclEnv () get_type_env -- yuk
857 ; case lookupNameEnv type_env name of
858 Just thing -> return thing
859 Nothing -> pprPanic "tcIfaceGlobal (local): not found:"
860 (ppr name $$ ppr type_env) }
864 { mb_thing <- importDecl name -- It's imported; go get it
866 Failed err -> failIfM err
867 Succeeded thing -> return thing
870 tcIfaceTyCon :: IfaceTyCon -> IfL TyCon
871 tcIfaceTyCon IfaceIntTc = tcWiredInTyCon intTyCon
872 tcIfaceTyCon IfaceBoolTc = tcWiredInTyCon boolTyCon
873 tcIfaceTyCon IfaceCharTc = tcWiredInTyCon charTyCon
874 tcIfaceTyCon IfaceListTc = tcWiredInTyCon listTyCon
875 tcIfaceTyCon IfacePArrTc = tcWiredInTyCon parrTyCon
876 tcIfaceTyCon (IfaceTupTc bx ar) = tcWiredInTyCon (tupleTyCon bx ar)
877 tcIfaceTyCon (IfaceTc ext_nm) = do { name <- lookupIfaceExt ext_nm
878 ; thing <- tcIfaceGlobal name
879 ; return (check_tc (tyThingTyCon thing)) }
882 check_tc tc = case toIfaceTyCon (error "urk") tc of
884 other -> pprTrace "check_tc" (ppr tc) tc
889 -- Even though we are in an interface file, we want to make
890 -- sure the instances and RULES of this tycon are loaded
891 -- Imagine: f :: Double -> Double
892 tcWiredInTyCon :: TyCon -> IfL TyCon
893 tcWiredInTyCon tc = do { loadWiredInHomeIface (tyConName tc)
896 tcIfaceClass :: IfaceExtName -> IfL Class
897 tcIfaceClass rdr_name = do { name <- lookupIfaceExt rdr_name
898 ; thing <- tcIfaceGlobal name
899 ; return (tyThingClass thing) }
901 tcIfaceDataCon :: IfaceExtName -> IfL DataCon
902 tcIfaceDataCon gbl = do { name <- lookupIfaceExt gbl
903 ; thing <- tcIfaceGlobal name
905 ADataCon dc -> return dc
906 other -> pprPanic "tcIfaceExtDC" (ppr gbl $$ ppr name$$ ppr thing) }
908 tcIfaceExtId :: IfaceExtName -> IfL Id
909 tcIfaceExtId gbl = do { name <- lookupIfaceExt gbl
910 ; thing <- tcIfaceGlobal name
913 other -> pprPanic "tcIfaceExtId" (ppr gbl $$ ppr name$$ ppr thing) }
916 %************************************************************************
920 %************************************************************************
923 bindIfaceBndr :: IfaceBndr -> (CoreBndr -> IfL a) -> IfL a
924 bindIfaceBndr (IfaceIdBndr bndr) thing_inside
925 = bindIfaceId bndr thing_inside
926 bindIfaceBndr (IfaceTvBndr bndr) thing_inside
927 = bindIfaceTyVar bndr thing_inside
929 bindIfaceBndrs :: [IfaceBndr] -> ([CoreBndr] -> IfL a) -> IfL a
930 bindIfaceBndrs [] thing_inside = thing_inside []
931 bindIfaceBndrs (b:bs) thing_inside
932 = bindIfaceBndr b $ \ b' ->
933 bindIfaceBndrs bs $ \ bs' ->
934 thing_inside (b':bs')
936 -----------------------
937 bindIfaceId :: IfaceIdBndr -> (Id -> IfL a) -> IfL a
938 bindIfaceId (occ, ty) thing_inside
939 = do { name <- newIfaceName (mkVarOccFS occ)
940 ; ty' <- tcIfaceType ty
941 ; let { id = mkLocalId name ty' }
942 ; extendIfaceIdEnv [id] (thing_inside id) }
944 bindIfaceIds :: [IfaceIdBndr] -> ([Id] -> IfL a) -> IfL a
945 bindIfaceIds bndrs thing_inside
946 = do { names <- newIfaceNames (map mkVarOccFS occs)
947 ; tys' <- mappM tcIfaceType tys
948 ; let { ids = zipWithEqual "tcCoreValBndr" mkLocalId names tys' }
949 ; extendIfaceIdEnv ids (thing_inside ids) }
951 (occs,tys) = unzip bndrs
954 -----------------------
955 newExtCoreBndr :: IfaceIdBndr -> IfL Id
956 newExtCoreBndr (var, ty)
957 = do { mod <- getIfModule
958 ; name <- newGlobalBinder mod (mkVarOccFS var) Nothing noSrcLoc
959 ; ty' <- tcIfaceType ty
960 ; return (mkLocalId name ty') }
962 -----------------------
963 bindIfaceTyVar :: IfaceTvBndr -> (TyVar -> IfL a) -> IfL a
964 bindIfaceTyVar (occ,kind) thing_inside
965 = do { name <- newIfaceName (mkTyVarOcc occ)
966 ; let tyvar = mk_iface_tyvar name kind
967 ; extendIfaceTyVarEnv [tyvar] (thing_inside tyvar) }
969 bindIfaceTyVars :: [IfaceTvBndr] -> ([TyVar] -> IfL a) -> IfL a
970 bindIfaceTyVars bndrs thing_inside
971 = do { names <- newIfaceNames (map mkTyVarOcc occs)
972 ; let tyvars = zipWith mk_iface_tyvar names kinds
973 ; extendIfaceTyVarEnv tyvars (thing_inside tyvars) }
975 (occs,kinds) = unzip bndrs
977 mk_iface_tyvar name kind = mkTyVar name kind