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,
21 newIfaceName, newIfaceNames, ifaceExportNames )
22 import BuildTyCl ( buildSynTyCon, buildAlgTyCon, buildDataCon, buildClass,
23 mkAbstractTyConRhs, mkDataTyConRhs, mkNewTyConRhs )
25 import TcType ( hoistForAllTys ) -- TEMPORARY HACK
26 import Type ( liftedTypeKind, splitTyConApp, mkSynTy, mkTyConApp,
27 mkTyVarTys, ThetaType,
28 mkGenTyConApp ) -- Don't remove this... see mkIfTcApp
29 import TypeRep ( Type(..), PredType(..) )
30 import TyCon ( TyCon, tyConName, isSynTyCon )
31 import HscTypes ( ExternalPackageState(..),
32 TyThing(..), tyThingClass, tyThingTyCon,
33 ModIface(..), ModDetails(..), HomeModInfo(..),
34 emptyModDetails, lookupTypeEnv, lookupType, typeEnvIds )
35 import InstEnv ( Instance(..), mkImportedInstance )
37 import CoreUtils ( exprType )
39 import CoreLint ( lintUnfolding )
40 import WorkWrap ( mkWrapper )
41 import Id ( Id, mkVanillaGlobal, mkLocalId )
42 import MkId ( mkFCallId )
43 import IdInfo ( IdInfo, CafInfo(..), WorkerInfo(..),
44 setUnfoldingInfoLazily, setAllStrictnessInfo, setWorkerInfo,
45 setArityInfo, setInlinePragInfo, setCafInfo,
46 vanillaIdInfo, newStrictnessInfo )
47 import Class ( Class )
48 import TyCon ( tyConDataCons, isTupleTyCon, mkForeignTyCon )
49 import DataCon ( DataCon, dataConWorkId, dataConTyVars, dataConArgTys, isVanillaDataCon )
50 import TysWiredIn ( tupleCon, tupleTyCon, listTyCon, intTyCon, boolTyCon, charTyCon, parrTyCon )
51 import Var ( TyVar, mkTyVar, tyVarKind )
52 import Name ( Name, nameModule, nameIsLocalOrFrom, isWiredInName,
53 wiredInNameTyThing_maybe, nameParent )
55 import OccName ( OccName )
56 import Module ( Module, lookupModuleEnv )
57 import UniqSupply ( initUs_ )
59 import ErrUtils ( Message )
60 import Maybes ( MaybeErr(..) )
61 import SrcLoc ( noSrcLoc )
62 import Util ( zipWithEqual, dropList, equalLength )
63 import DynFlags ( DynFlag(..), isOneShot )
72 An IfaceDecl is populated with RdrNames, and these are not renamed to
73 Names before typechecking, because there should be no scope errors etc.
75 -- For (b) consider: f = $(...h....)
76 -- where h is imported, and calls f via an hi-boot file.
77 -- This is bad! But it is not seen as a staging error, because h
78 -- is indeed imported. We don't want the type-checker to black-hole
79 -- when simplifying and compiling the splice!
81 -- Simple solution: discard any unfolding that mentions a variable
82 -- bound in this module (and hence not yet processed).
83 -- The discarding happens when forkM finds a type error.
85 %************************************************************************
87 %* tcImportDecl is the key function for "faulting in" *
90 %************************************************************************
92 The main idea is this. We are chugging along type-checking source code, and
93 find a reference to GHC.Base.map. We call tcLookupGlobal, which doesn't find
94 it in the EPS type envt. So it
96 2 gets the decl for GHC.Base.map
97 3 typechecks it via tcIfaceDecl
98 4 and adds it to the type env in the EPS
100 Note that DURING STEP 4, we may find that map's type mentions a type
101 constructor that also
103 Notice that for imported things we read the current version from the EPS
104 mutable variable. This is important in situations like
106 where the code that e1 expands to might import some defns that
107 also turn out to be needed by the code that e2 expands to.
110 tcImportDecl :: Name -> TcM TyThing
111 -- Entry point for *source-code* uses of importDecl
113 | Just thing <- wiredInNameTyThing_maybe name
114 = do { initIfaceTcRn (loadWiredInHomeIface name)
117 = do { traceIf (text "tcLookupGlobal" <+> ppr name)
118 ; mb_thing <- initIfaceTcRn (importDecl name)
120 Succeeded thing -> return thing
121 Failed err -> failWithTc err }
123 checkWiredInTyCon :: TyCon -> TcM ()
124 -- Ensure that the home module of the TyCon (and hence its instances)
125 -- are loaded. It might not be a wired-in tycon (see the calls in TcUnify),
126 -- in which case this is a no-op.
128 | not (isWiredInName tc_name)
131 = do { mod <- getModule
132 ; if nameIsLocalOrFrom mod tc_name then
133 -- Don't look for (non-existent) Float.hi when
134 -- compiling Float.lhs, which mentions Float of course
136 else -- A bit yukky to call initIfaceTcRn here
137 initIfaceTcRn (loadWiredInHomeIface tc_name)
140 tc_name = tyConName tc
142 importDecl :: Name -> IfM lcl (MaybeErr Message TyThing)
143 -- Get the TyThing for this Name from an interface file
144 -- It's not a wired-in thing -- the caller caught that
146 = ASSERT( not (isWiredInName name) )
149 -- Load the interface, which should populate the PTE
150 ; mb_iface <- loadInterface nd_doc (nameModule name) ImportBySystem
152 Failed err_msg -> return (Failed err_msg) ;
153 Succeeded iface -> do
155 -- Now look it up again; this time we should find it
157 ; case lookupTypeEnv (eps_PTE eps) name of
158 Just thing -> return (Succeeded thing)
159 Nothing -> return (Failed not_found_msg)
162 nd_doc = ptext SLIT("Need decl for") <+> ppr name
163 not_found_msg = hang (ptext SLIT("Can't find interface-file declaration for") <+> ppr (nameParent name))
164 2 (vcat [ptext SLIT("Probable cause: bug in .hi-boot file, or inconsistent .hi file"),
165 ptext SLIT("Use -ddump-if-trace to get an idea of which file caused the error")])
168 %************************************************************************
170 Type-checking a complete interface
172 %************************************************************************
174 Suppose we discover we don't need to recompile. Then we must type
175 check the old interface file. This is a bit different to the
176 incremental type checking we do as we suck in interface files. Instead
177 we do things similarly as when we are typechecking source decls: we
178 bring into scope the type envt for the interface all at once, using a
179 knot. Remember, the decls aren't necessarily in dependency order --
180 and even if they were, the type decls might be mutually recursive.
183 typecheckIface :: ModIface -- Get the decls from here
184 -> TcRnIf gbl lcl ModDetails
186 = initIfaceTc iface $ \ tc_env_var -> do
187 -- The tc_env_var is freshly allocated, private to
188 -- type-checking this particular interface
189 { -- Get the right set of decls and rules. If we are compiling without -O
190 -- we discard pragmas before typechecking, so that we don't "see"
191 -- information that we shouldn't. From a versioning point of view
192 -- It's not actually *wrong* to do so, but in fact GHCi is unable
193 -- to handle unboxed tuples, so it must not see unfoldings.
194 ignore_prags <- doptM Opt_IgnoreInterfacePragmas
196 -- Load & typecheck the decls
197 ; decl_things <- loadDecls ignore_prags (mi_decls iface)
199 ; let type_env = mkNameEnv decl_things
200 ; writeMutVar tc_env_var type_env
202 -- Now do those rules and instances
203 ; let { rules | ignore_prags = []
204 | otherwise = mi_rules iface
205 ; dfuns = mi_insts iface
207 ; dfuns <- mapM tcIfaceInst dfuns
208 ; rules <- mapM tcIfaceRule rules
211 ; exports <- ifaceExportNames (mi_exports iface)
214 ; return (ModDetails { md_types = type_env,
217 md_exports = exports })
222 %************************************************************************
224 Type and class declarations
226 %************************************************************************
229 tcHiBootIface :: Module -> TcRn ModDetails
230 -- Load the hi-boot iface for the module being compiled,
231 -- if it indeed exists in the transitive closure of imports
232 -- Return the ModDetails, empty if no hi-boot iface
234 = do { traceIf (text "loadHiBootInterface" <+> ppr mod)
236 ; mode <- getGhciMode
237 ; if not (isOneShot mode)
238 -- In --make and interactive mode, if this module has an hs-boot file
239 -- we'll have compiled it already, and it'll be in the HPT
240 then do { hpt <- getHpt
241 ; case lookupModuleEnv hpt mod of
242 Just info -> return (hm_details info)
243 Nothing -> return emptyModDetails }
246 -- OK, so we're in one-shot mode.
247 -- In that case, we're read all the direct imports by now,
248 -- so eps_is_boot will record if any of our imports mention us by
249 -- way of hi-boot file
251 ; case lookupModuleEnv (eps_is_boot eps) mod of {
252 Nothing -> return emptyModDetails ; -- The typical case
254 Just (_, False) -> failWithTc moduleLoop ;
255 -- Someone below us imported us!
256 -- This is a loop with no hi-boot in the way
258 Just (mod, True) -> -- There's a hi-boot interface below us
260 do { read_result <- findAndReadIface
261 True -- Explicit import?
265 ; case read_result of
266 Failed err -> failWithTc (elaborate err)
267 Succeeded (iface, _path) -> typecheckIface iface
270 need = ptext SLIT("Need the hi-boot interface for") <+> ppr mod
271 <+> ptext SLIT("to compare against the Real Thing")
273 moduleLoop = ptext SLIT("Circular imports: module") <+> quotes (ppr mod)
274 <+> ptext SLIT("depends on itself")
276 elaborate err = hang (ptext SLIT("Could not find hi-boot interface for") <+>
277 quotes (ppr mod) <> colon) 4 err
281 %************************************************************************
283 Type and class declarations
285 %************************************************************************
287 When typechecking a data type decl, we *lazily* (via forkM) typecheck
288 the constructor argument types. This is in the hope that we may never
289 poke on those argument types, and hence may never need to load the
290 interface files for types mentioned in the arg types.
293 data Foo.S = MkS Baz.T
294 Mabye we can get away without even loading the interface for Baz!
296 This is not just a performance thing. Suppose we have
297 data Foo.S = MkS Baz.T
298 data Baz.T = MkT Foo.S
299 (in different interface files, of course).
300 Now, first we load and typecheck Foo.S, and add it to the type envt.
301 If we do explore MkS's argument, we'll load and typecheck Baz.T.
302 If we explore MkT's argument we'll find Foo.S already in the envt.
304 If we typechecked constructor args eagerly, when loading Foo.S we'd try to
305 typecheck the type Baz.T. So we'd fault in Baz.T... and then need Foo.S...
306 which isn't done yet.
308 All very cunning. However, there is a rather subtle gotcha which bit
309 me when developing this stuff. When we typecheck the decl for S, we
310 extend the type envt with S, MkS, and all its implicit Ids. Suppose
311 (a bug, but it happened) that the list of implicit Ids depended in
312 turn on the constructor arg types. Then the following sequence of
314 * we build a thunk <t> for the constructor arg tys
315 * we build a thunk for the extended type environment (depends on <t>)
316 * we write the extended type envt into the global EPS mutvar
318 Now we look something up in the type envt
320 * which reads the global type envt out of the global EPS mutvar
321 * but that depends in turn on <t>
323 It's subtle, because, it'd work fine if we typechecked the constructor args
324 eagerly -- they don't need the extended type envt. They just get the extended
325 type envt by accident, because they look at it later.
327 What this means is that the implicitTyThings MUST NOT DEPEND on any of
332 tcIfaceDecl :: IfaceDecl -> IfL TyThing
334 tcIfaceDecl (IfaceId {ifName = occ_name, ifType = iface_type, ifIdInfo = info})
335 = do { name <- lookupIfaceTop occ_name
336 ; ty <- tcIfaceType iface_type
337 ; info <- tcIdInfo name ty info
338 ; return (AnId (mkVanillaGlobal name ty info)) }
340 tcIfaceDecl (IfaceData {ifName = occ_name,
344 ifVrcs = arg_vrcs, ifRec = is_rec,
345 ifGeneric = want_generic })
346 = do { tc_name <- lookupIfaceTop occ_name
347 ; bindIfaceTyVars tv_bndrs $ \ tyvars -> do
349 { tycon <- fixM ( \ tycon -> do
350 { stupid_theta <- tcIfaceCtxt ctxt
351 ; cons <- tcIfaceDataCons tycon tyvars rdr_cons
352 ; buildAlgTyCon tc_name tyvars stupid_theta
353 cons arg_vrcs is_rec want_generic
355 ; traceIf (text "tcIfaceDecl4" <+> ppr tycon)
356 ; return (ATyCon tycon)
359 tcIfaceDecl (IfaceSyn {ifName = occ_name, ifTyVars = tv_bndrs,
360 ifSynRhs = rdr_rhs_ty, ifVrcs = arg_vrcs})
361 = bindIfaceTyVars tv_bndrs $ \ tyvars -> do
362 { tc_name <- lookupIfaceTop occ_name
363 ; rhs_ty <- tcIfaceType rdr_rhs_ty
364 ; return (ATyCon (buildSynTyCon tc_name tyvars rhs_ty arg_vrcs))
367 tcIfaceDecl (IfaceClass {ifCtxt = rdr_ctxt, ifName = occ_name, ifTyVars = tv_bndrs,
368 ifFDs = rdr_fds, ifSigs = rdr_sigs,
369 ifVrcs = tc_vrcs, ifRec = tc_isrec })
370 = bindIfaceTyVars tv_bndrs $ \ tyvars -> do
371 { cls_name <- lookupIfaceTop occ_name
372 ; ctxt <- tcIfaceCtxt rdr_ctxt
373 ; sigs <- mappM tc_sig rdr_sigs
374 ; fds <- mappM tc_fd rdr_fds
375 ; cls <- buildClass cls_name tyvars ctxt fds sigs tc_isrec tc_vrcs
376 ; return (AClass cls) }
378 tc_sig (IfaceClassOp occ dm rdr_ty)
379 = do { op_name <- lookupIfaceTop occ
380 ; op_ty <- forkM (mk_doc op_name rdr_ty) (tcIfaceType rdr_ty)
381 -- Must be done lazily for just the same reason as the
382 -- context of a data decl: the type sig might mention the
383 -- class being defined
384 ; return (op_name, dm, op_ty) }
386 mk_doc op_name op_ty = ptext SLIT("Class op") <+> sep [ppr op_name, ppr op_ty]
388 tc_fd (tvs1, tvs2) = do { tvs1' <- mappM tcIfaceTyVar tvs1
389 ; tvs2' <- mappM tcIfaceTyVar tvs2
390 ; return (tvs1', tvs2') }
392 tcIfaceDecl (IfaceForeign {ifName = rdr_name, ifExtName = ext_name})
393 = do { name <- lookupIfaceTop rdr_name
394 ; return (ATyCon (mkForeignTyCon name ext_name
395 liftedTypeKind 0 [])) }
397 tcIfaceDataCons tycon tc_tyvars if_cons
399 IfAbstractTyCon -> return mkAbstractTyConRhs
400 IfDataTyCon cons -> do { data_cons <- mappM tc_con_decl cons
401 ; return (mkDataTyConRhs data_cons) }
402 IfNewTyCon con -> do { data_con <- tc_con_decl con
403 ; return (mkNewTyConRhs tycon data_con) }
405 tc_con_decl (IfVanillaCon { ifConOcc = occ, ifConInfix = is_infix, ifConArgTys = args,
406 ifConStricts = stricts, ifConFields = field_lbls})
407 = do { name <- lookupIfaceTop occ
408 -- Read the argument types, but lazily to avoid faulting in
409 -- the component types unless they are really needed
410 ; arg_tys <- forkM (mk_doc name) (mappM tcIfaceType args)
411 ; lbl_names <- mappM lookupIfaceTop field_lbls
412 ; buildDataCon name is_infix True {- Vanilla -}
414 tc_tyvars [] arg_tys tycon
415 (mkTyVarTys tc_tyvars) -- Vanilla => we know result tys
418 tc_con_decl (IfGadtCon { ifConTyVars = con_tvs,
419 ifConOcc = occ, ifConCtxt = ctxt,
420 ifConArgTys = args, ifConResTys = ress,
421 ifConStricts = stricts})
422 = bindIfaceTyVars con_tvs $ \ con_tyvars -> do
423 { name <- lookupIfaceTop occ
424 ; theta <- tcIfaceCtxt ctxt -- Laziness seems not worth the bother here
425 -- At one stage I thought that this context checking *had*
426 -- to be lazy, because of possible mutual recursion between the
427 -- type and the classe:
429 -- class Real a where { toRat :: a -> Ratio Integer }
430 -- data (Real a) => Ratio a = ...
431 -- But now I think that the laziness in checking class ops breaks
432 -- the loop, so no laziness needed
434 -- Read the argument types, but lazily to avoid faulting in
435 -- the component types unless they are really needed
436 ; arg_tys <- forkM (mk_doc name) (mappM tcIfaceType args)
437 ; res_tys <- forkM (mk_doc name) (mappM tcIfaceType ress)
439 ; buildDataCon name False {- Not infix -} False {- Not vanilla -}
440 stricts [{- No fields -}]
442 arg_tys tycon res_tys
444 mk_doc con_name = ptext SLIT("Constructor") <+> ppr con_name
448 %************************************************************************
452 %************************************************************************
455 tcIfaceInst :: IfaceInst -> IfL Instance
456 tcIfaceInst (IfaceInst { ifDFun = dfun_occ, ifOFlag = oflag,
457 ifInstCls = cls, ifInstTys = mb_tcs,
459 = do { dfun <- forkM (ptext SLIT("Dict fun") <+> ppr dfun_occ) $
460 tcIfaceExtId (LocalTop dfun_occ)
461 ; cls' <- lookupIfaceExt cls
462 ; mb_tcs' <- mapM do_tc mb_tcs
463 ; return (mkImportedInstance cls' mb_tcs' orph dfun oflag) }
465 do_tc Nothing = return Nothing
466 do_tc (Just tc) = do { tc' <- lookupIfaceTc tc; return (Just tc') }
470 %************************************************************************
474 %************************************************************************
476 We move a IfaceRule from eps_rules to eps_rule_base when all its LHS free vars
477 are in the type environment. However, remember that typechecking a Rule may
478 (as a side effect) augment the type envt, and so we may need to iterate the process.
481 tcIfaceRule :: IfaceRule -> IfL CoreRule
482 tcIfaceRule (IfaceRule {ifRuleName = name, ifActivation = act, ifRuleBndrs = bndrs,
483 ifRuleHead = fn, ifRuleArgs = args, ifRuleRhs = rhs,
485 = do { fn' <- lookupIfaceExt fn
486 ; ~(bndrs', args', rhs') <-
487 -- Typecheck the payload lazily, in the hope it'll never be looked at
488 forkM (ptext SLIT("Rule") <+> ftext name) $
489 bindIfaceBndrs bndrs $ \ bndrs' ->
490 do { args' <- mappM tcIfaceExpr args
491 ; rhs' <- tcIfaceExpr rhs
492 ; return (bndrs', args', rhs') }
493 ; mb_tcs <- mapM ifTopFreeName args
494 ; returnM (Rule { ru_name = name, ru_fn = fn', ru_act = act,
495 ru_bndrs = bndrs', ru_args = args',
496 ru_rhs = rhs', ru_orph = orph,
498 ru_local = isLocalIfaceExtName fn }) }
500 -- This function *must* mirror exactly what Rules.topFreeName does
501 -- We could have stored the ru_rough field in the iface file
502 -- but that would be redundant, I think.
503 -- The only wrinkle is that we must not be deceived by
504 -- type syononyms at the top of a type arg. Since
505 -- we can't tell at this point, we are careful not
506 -- to write them out in coreRuleToIfaceRule
507 ifTopFreeName :: IfaceExpr -> IfL (Maybe Name)
508 ifTopFreeName (IfaceType (IfaceTyConApp tc _ ))
509 = do { n <- lookupIfaceTc tc
511 ifTopFreeName (IfaceApp f a) = ifTopFreeName f
512 ifTopFreeName (IfaceExt ext) = do { n <- lookupIfaceExt ext
514 ifTopFreeName other = return Nothing
518 %************************************************************************
522 %************************************************************************
525 tcIfaceType :: IfaceType -> IfL Type
526 tcIfaceType (IfaceTyVar n) = do { tv <- tcIfaceTyVar n; return (TyVarTy tv) }
527 tcIfaceType (IfaceAppTy t1 t2) = do { t1' <- tcIfaceType t1; t2' <- tcIfaceType t2; return (AppTy t1' t2') }
528 tcIfaceType (IfaceFunTy t1 t2) = do { t1' <- tcIfaceType t1; t2' <- tcIfaceType t2; return (FunTy t1' t2') }
529 tcIfaceType (IfaceTyConApp tc ts) = do { tc' <- tcIfaceTyCon tc; ts' <- tcIfaceTypes ts; return (mkIfTcApp tc' ts') }
530 tcIfaceType (IfaceForAllTy tv t) = bindIfaceTyVar tv $ \ tv' -> do { t' <- tcIfaceType t; return (ForAllTy tv' t') }
531 tcIfaceType (IfacePredTy st) = do { st' <- tcIfacePredType st; return (PredTy st') }
533 tcIfaceTypes tys = mapM tcIfaceType tys
535 mkIfTcApp :: TyCon -> [Type] -> Type
536 -- In interface files we retain type synonyms (for brevity and better error
537 -- messages), but type synonyms can expand into non-hoisted types (ones with
538 -- foralls to the right of an arrow), so we must be careful to hoist them here.
539 -- This hack should go away when we get rid of hoisting.
540 -- Then we should go back to mkGenTyConApp or something like it
542 | isSynTyCon tc = hoistForAllTys (mkSynTy tc tys)
543 | otherwise = mkTyConApp tc tys
545 -----------------------------------------
546 tcIfacePredType :: IfacePredType -> IfL PredType
547 tcIfacePredType (IfaceClassP cls ts) = do { cls' <- tcIfaceClass cls; ts' <- tcIfaceTypes ts; return (ClassP cls' ts') }
548 tcIfacePredType (IfaceIParam ip t) = do { ip' <- newIPName ip; t' <- tcIfaceType t; return (IParam ip' t') }
550 -----------------------------------------
551 tcIfaceCtxt :: IfaceContext -> IfL ThetaType
552 tcIfaceCtxt sts = mappM tcIfacePredType sts
556 %************************************************************************
560 %************************************************************************
563 tcIfaceExpr :: IfaceExpr -> IfL CoreExpr
564 tcIfaceExpr (IfaceType ty)
565 = tcIfaceType ty `thenM` \ ty' ->
568 tcIfaceExpr (IfaceLcl name)
569 = tcIfaceLclId name `thenM` \ id ->
572 tcIfaceExpr (IfaceExt gbl)
573 = tcIfaceExtId gbl `thenM` \ id ->
576 tcIfaceExpr (IfaceLit lit)
579 tcIfaceExpr (IfaceFCall cc ty)
580 = tcIfaceType ty `thenM` \ ty' ->
581 newUnique `thenM` \ u ->
582 returnM (Var (mkFCallId u cc ty'))
584 tcIfaceExpr (IfaceTuple boxity args)
585 = mappM tcIfaceExpr args `thenM` \ args' ->
587 -- Put the missing type arguments back in
588 con_args = map (Type . exprType) args' ++ args'
590 returnM (mkApps (Var con_id) con_args)
593 con_id = dataConWorkId (tupleCon boxity arity)
596 tcIfaceExpr (IfaceLam bndr body)
597 = bindIfaceBndr bndr $ \ bndr' ->
598 tcIfaceExpr body `thenM` \ body' ->
599 returnM (Lam bndr' body')
601 tcIfaceExpr (IfaceApp fun arg)
602 = tcIfaceExpr fun `thenM` \ fun' ->
603 tcIfaceExpr arg `thenM` \ arg' ->
604 returnM (App fun' arg')
606 tcIfaceExpr (IfaceCase scrut case_bndr ty alts)
607 = tcIfaceExpr scrut `thenM` \ scrut' ->
608 newIfaceName case_bndr `thenM` \ case_bndr_name ->
610 scrut_ty = exprType scrut'
611 case_bndr' = mkLocalId case_bndr_name scrut_ty
612 tc_app = splitTyConApp scrut_ty
613 -- NB: Won't always succeed (polymoprhic case)
614 -- but won't be demanded in those cases
615 -- NB: not tcSplitTyConApp; we are looking at Core here
616 -- look through non-rec newtypes to find the tycon that
617 -- corresponds to the datacon in this case alternative
619 extendIfaceIdEnv [case_bndr'] $
620 mappM (tcIfaceAlt tc_app) alts `thenM` \ alts' ->
621 tcIfaceType ty `thenM` \ ty' ->
622 returnM (Case scrut' case_bndr' ty' alts')
624 tcIfaceExpr (IfaceLet (IfaceNonRec bndr rhs) body)
625 = tcIfaceExpr rhs `thenM` \ rhs' ->
626 bindIfaceId bndr $ \ bndr' ->
627 tcIfaceExpr body `thenM` \ body' ->
628 returnM (Let (NonRec bndr' rhs') body')
630 tcIfaceExpr (IfaceLet (IfaceRec pairs) body)
631 = bindIfaceIds bndrs $ \ bndrs' ->
632 mappM tcIfaceExpr rhss `thenM` \ rhss' ->
633 tcIfaceExpr body `thenM` \ body' ->
634 returnM (Let (Rec (bndrs' `zip` rhss')) body')
636 (bndrs, rhss) = unzip pairs
638 tcIfaceExpr (IfaceNote note expr)
639 = tcIfaceExpr expr `thenM` \ expr' ->
641 IfaceCoerce to_ty -> tcIfaceType to_ty `thenM` \ to_ty' ->
642 returnM (Note (Coerce to_ty'
643 (exprType expr')) expr')
644 IfaceInlineCall -> returnM (Note InlineCall expr')
645 IfaceInlineMe -> returnM (Note InlineMe expr')
646 IfaceSCC cc -> returnM (Note (SCC cc) expr')
647 IfaceCoreNote n -> returnM (Note (CoreNote n) expr')
649 -------------------------
650 tcIfaceAlt _ (IfaceDefault, names, rhs)
651 = ASSERT( null names )
652 tcIfaceExpr rhs `thenM` \ rhs' ->
653 returnM (DEFAULT, [], rhs')
655 tcIfaceAlt _ (IfaceLitAlt lit, names, rhs)
656 = ASSERT( null names )
657 tcIfaceExpr rhs `thenM` \ rhs' ->
658 returnM (LitAlt lit, [], rhs')
660 -- A case alternative is made quite a bit more complicated
661 -- by the fact that we omit type annotations because we can
662 -- work them out. True enough, but its not that easy!
663 tcIfaceAlt (tycon, inst_tys) (IfaceDataAlt data_occ, arg_occs, rhs)
664 = do { let tycon_mod = nameModule (tyConName tycon)
665 ; con <- tcIfaceDataCon (ExtPkg tycon_mod data_occ)
666 ; ASSERT2( con `elem` tyConDataCons tycon,
667 ppr con $$ ppr tycon $$ ppr (tyConDataCons tycon) )
669 if isVanillaDataCon con then
670 tcVanillaAlt con inst_tys arg_occs rhs
673 arg_names <- newIfaceNames arg_occs
674 ; let tyvars = [ mkTyVar name (tyVarKind tv)
675 | (name,tv) <- arg_names `zip` dataConTyVars con]
676 arg_tys = dataConArgTys con (mkTyVarTys tyvars)
677 id_names = dropList tyvars arg_names
678 arg_ids = ASSERT2( equalLength id_names arg_tys,
679 ppr (con, arg_names, rhs) $$ ppr tyvars $$ ppr arg_tys )
680 zipWith mkLocalId id_names arg_tys
682 ; rhs' <- extendIfaceTyVarEnv tyvars $
683 extendIfaceIdEnv arg_ids $
685 ; return (DataAlt con, tyvars ++ arg_ids, rhs') }}
687 tcIfaceAlt (tycon, inst_tys) (IfaceTupleAlt boxity, arg_occs, rhs)
688 = ASSERT( isTupleTyCon tycon )
689 do { let [data_con] = tyConDataCons tycon
690 ; tcVanillaAlt data_con inst_tys arg_occs rhs }
692 tcVanillaAlt data_con inst_tys arg_occs rhs
693 = do { arg_names <- newIfaceNames arg_occs
694 ; let arg_tys = dataConArgTys data_con inst_tys
695 ; let arg_ids = ASSERT2( equalLength arg_names arg_tys,
696 ppr data_con <+> ppr inst_tys <+> ppr arg_occs $$ ppr rhs )
697 zipWith mkLocalId arg_names arg_tys
698 ; rhs' <- extendIfaceIdEnv arg_ids (tcIfaceExpr rhs)
699 ; returnM (DataAlt data_con, arg_ids, rhs') }
704 tcExtCoreBindings :: [IfaceBinding] -> IfL [CoreBind] -- Used for external core
705 tcExtCoreBindings [] = return []
706 tcExtCoreBindings (b:bs) = do_one b (tcExtCoreBindings bs)
708 do_one :: IfaceBinding -> IfL [CoreBind] -> IfL [CoreBind]
709 do_one (IfaceNonRec bndr rhs) thing_inside
710 = do { rhs' <- tcIfaceExpr rhs
711 ; bndr' <- newExtCoreBndr bndr
712 ; extendIfaceIdEnv [bndr'] $ do
713 { core_binds <- thing_inside
714 ; return (NonRec bndr' rhs' : core_binds) }}
716 do_one (IfaceRec pairs) thing_inside
717 = do { bndrs' <- mappM newExtCoreBndr bndrs
718 ; extendIfaceIdEnv bndrs' $ do
719 { rhss' <- mappM tcIfaceExpr rhss
720 ; core_binds <- thing_inside
721 ; return (Rec (bndrs' `zip` rhss') : core_binds) }}
723 (bndrs,rhss) = unzip pairs
727 %************************************************************************
731 %************************************************************************
734 tcIdInfo :: Name -> Type -> IfaceIdInfo -> IfL IdInfo
735 tcIdInfo name ty NoInfo = return vanillaIdInfo
736 tcIdInfo name ty (HasInfo info) = foldlM tcPrag init_info info
738 -- Set the CgInfo to something sensible but uninformative before
739 -- we start; default assumption is that it has CAFs
740 init_info = vanillaIdInfo
742 tcPrag info HsNoCafRefs = returnM (info `setCafInfo` NoCafRefs)
743 tcPrag info (HsArity arity) = returnM (info `setArityInfo` arity)
744 tcPrag info (HsStrictness str) = returnM (info `setAllStrictnessInfo` Just str)
746 -- The next two are lazy, so they don't transitively suck stuff in
747 tcPrag info (HsWorker nm arity) = tcWorkerInfo ty info nm arity
748 tcPrag info (HsUnfold inline_prag expr)
749 = tcPragExpr name expr `thenM` \ maybe_expr' ->
751 -- maybe_expr' doesn't get looked at if the unfolding
752 -- is never inspected; so the typecheck doesn't even happen
753 unfold_info = case maybe_expr' of
754 Nothing -> noUnfolding
755 Just expr' -> mkTopUnfolding expr'
757 returnM (info `setUnfoldingInfoLazily` unfold_info
758 `setInlinePragInfo` inline_prag)
762 tcWorkerInfo ty info wkr arity
763 = do { mb_wkr_id <- forkM_maybe doc (tcIfaceExtId wkr)
765 -- We return without testing maybe_wkr_id, but as soon as info is
766 -- looked at we will test it. That's ok, because its outside the
767 -- knot; and there seems no big reason to further defer the
768 -- tcIfaceId lookup. (Contrast with tcPragExpr, where postponing walking
769 -- over the unfolding until it's actually used does seem worth while.)
770 ; us <- newUniqueSupply
772 ; returnM (case mb_wkr_id of
774 Just wkr_id -> add_wkr_info us wkr_id info) }
776 doc = text "Worker for" <+> ppr wkr
777 add_wkr_info us wkr_id info
778 = info `setUnfoldingInfoLazily` mk_unfolding us wkr_id
779 `setWorkerInfo` HasWorker wkr_id arity
781 mk_unfolding us wkr_id = mkTopUnfolding (initUs_ us (mkWrapper ty strict_sig) wkr_id)
783 -- We are relying here on strictness info always appearing
784 -- before worker info, fingers crossed ....
785 strict_sig = case newStrictnessInfo info of
787 Nothing -> pprPanic "Worker info but no strictness for" (ppr wkr)
790 For unfoldings we try to do the job lazily, so that we never type check
791 an unfolding that isn't going to be looked at.
794 tcPragExpr :: Name -> IfaceExpr -> IfL (Maybe CoreExpr)
797 tcIfaceExpr expr `thenM` \ core_expr' ->
799 -- Check for type consistency in the unfolding
800 ifOptM Opt_DoCoreLinting (
801 get_in_scope_ids `thenM` \ in_scope ->
802 case lintUnfolding noSrcLoc in_scope core_expr' of
803 Nothing -> returnM ()
804 Just fail_msg -> pprPanic "Iface Lint failure" (doc <+> fail_msg)
809 doc = text "Unfolding of" <+> ppr name
810 get_in_scope_ids -- Urgh; but just for linting
812 do { env <- getGblEnv
813 ; case if_rec_types env of {
814 Nothing -> return [] ;
815 Just (_, get_env) -> do
816 { type_env <- get_env
817 ; return (typeEnvIds type_env) }}}
822 %************************************************************************
824 Getting from Names to TyThings
826 %************************************************************************
829 tcIfaceGlobal :: Name -> IfL TyThing
831 | Just thing <- wiredInNameTyThing_maybe name
832 = do { loadWiredInHomeIface name; return thing }
833 -- Even though we are in an interface file, we want to make
834 -- sure its instances are loaded (imagine f :: Double -> Double)
835 -- and its RULES are loaded too
837 = do { (eps,hpt) <- getEpsAndHpt
838 ; case lookupType hpt (eps_PTE eps) name of {
839 Just thing -> return thing ;
843 ; case if_rec_types env of {
844 Just (mod, get_type_env)
845 | nameIsLocalOrFrom mod name
846 -> do -- It's defined in the module being compiled
847 { type_env <- setLclEnv () get_type_env -- yuk
848 ; case lookupNameEnv type_env name of
849 Just thing -> return thing
850 Nothing -> pprPanic "tcIfaceGlobal (local): not found:"
851 (ppr name $$ ppr type_env) }
855 { mb_thing <- importDecl name -- It's imported; go get it
857 Failed err -> failIfM err
858 Succeeded thing -> return thing
861 tcIfaceTyCon :: IfaceTyCon -> IfL TyCon
862 tcIfaceTyCon IfaceIntTc = return intTyCon
863 tcIfaceTyCon IfaceBoolTc = return boolTyCon
864 tcIfaceTyCon IfaceCharTc = return charTyCon
865 tcIfaceTyCon IfaceListTc = return listTyCon
866 tcIfaceTyCon IfacePArrTc = return parrTyCon
867 tcIfaceTyCon (IfaceTupTc bx ar) = return (tupleTyCon bx ar)
868 tcIfaceTyCon (IfaceTc ext_nm) = do { name <- lookupIfaceExt ext_nm
869 ; thing <- tcIfaceGlobal name
870 ; return (tyThingTyCon thing) }
872 tcIfaceClass :: IfaceExtName -> IfL Class
873 tcIfaceClass rdr_name = do { name <- lookupIfaceExt rdr_name
874 ; thing <- tcIfaceGlobal name
875 ; return (tyThingClass thing) }
877 tcIfaceDataCon :: IfaceExtName -> IfL DataCon
878 tcIfaceDataCon gbl = do { name <- lookupIfaceExt gbl
879 ; thing <- tcIfaceGlobal name
881 ADataCon dc -> return dc
882 other -> pprPanic "tcIfaceExtDC" (ppr gbl $$ ppr name$$ ppr thing) }
884 tcIfaceExtId :: IfaceExtName -> IfL Id
885 tcIfaceExtId gbl = do { name <- lookupIfaceExt gbl
886 ; thing <- tcIfaceGlobal name
889 other -> pprPanic "tcIfaceExtId" (ppr gbl $$ ppr name$$ ppr thing) }
892 %************************************************************************
896 %************************************************************************
899 bindIfaceBndr :: IfaceBndr -> (CoreBndr -> IfL a) -> IfL a
900 bindIfaceBndr (IfaceIdBndr bndr) thing_inside
901 = bindIfaceId bndr thing_inside
902 bindIfaceBndr (IfaceTvBndr bndr) thing_inside
903 = bindIfaceTyVar bndr thing_inside
905 bindIfaceBndrs :: [IfaceBndr] -> ([CoreBndr] -> IfL a) -> IfL a
906 bindIfaceBndrs [] thing_inside = thing_inside []
907 bindIfaceBndrs (b:bs) thing_inside
908 = bindIfaceBndr b $ \ b' ->
909 bindIfaceBndrs bs $ \ bs' ->
910 thing_inside (b':bs')
912 -----------------------
913 bindIfaceId :: (OccName, IfaceType) -> (Id -> IfL a) -> IfL a
914 bindIfaceId (occ, ty) thing_inside
915 = do { name <- newIfaceName occ
916 ; ty' <- tcIfaceType ty
917 ; let { id = mkLocalId name ty' }
918 ; extendIfaceIdEnv [id] (thing_inside id) }
920 bindIfaceIds :: [(OccName, IfaceType)] -> ([Id] -> IfL a) -> IfL a
921 bindIfaceIds bndrs thing_inside
922 = do { names <- newIfaceNames occs
923 ; tys' <- mappM tcIfaceType tys
924 ; let { ids = zipWithEqual "tcCoreValBndr" mkLocalId names tys' }
925 ; extendIfaceIdEnv ids (thing_inside ids) }
927 (occs,tys) = unzip bndrs
930 -----------------------
931 newExtCoreBndr :: (OccName, IfaceType) -> IfL Id
932 newExtCoreBndr (occ, ty)
933 = do { mod <- getIfModule
934 ; name <- newGlobalBinder mod occ Nothing noSrcLoc
935 ; ty' <- tcIfaceType ty
936 ; return (mkLocalId name ty') }
938 -----------------------
939 bindIfaceTyVar :: IfaceTvBndr -> (TyVar -> IfL a) -> IfL a
940 bindIfaceTyVar (occ,kind) thing_inside
941 = do { name <- newIfaceName occ
942 ; let tyvar = mk_iface_tyvar name kind
943 ; extendIfaceTyVarEnv [tyvar] (thing_inside tyvar) }
945 bindIfaceTyVars :: [IfaceTvBndr] -> ([TyVar] -> IfL a) -> IfL a
946 bindIfaceTyVars bndrs thing_inside
947 = do { names <- newIfaceNames occs
948 ; let tyvars = zipWith mk_iface_tyvar names kinds
949 ; extendIfaceTyVarEnv tyvars (thing_inside tyvars) }
951 (occs,kinds) = unzip bndrs
953 mk_iface_tyvar name kind = mkTyVar name kind