% % (c) The University of Glasgow 2006 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998 % Type checking of type signatures in interface files \begin{code} module TcIface ( tcImportDecl, importDecl, checkWiredInTyCon, tcHiBootIface, typecheckIface, tcIfaceDecl, tcIfaceInst, tcIfaceFamInst, tcIfaceRules, tcIfaceVectInfo, tcIfaceAnnotations, tcIfaceGlobal, tcExtCoreBindings ) where #include "HsVersions.h" import IfaceSyn import LoadIface import IfaceEnv import BuildTyCl import TcRnMonad import TcType import Type import Coercion import TypeRep import HscTypes import Annotations import InstEnv import FamInstEnv import CoreSyn import CoreUtils import CoreUnfold import CoreLint import WorkWrap import MkCore( castBottomExpr ) import Id import MkId import IdInfo import Class import TyCon import CoAxiom import DataCon import PrelNames import TysWiredIn import TysPrim ( superKindTyConName ) import BasicTypes ( Arity, strongLoopBreaker ) import Literal import qualified Var import VarEnv import VarSet import Name import NameEnv import NameSet import OccurAnal ( occurAnalyseExpr ) import Demand ( isBottomingSig ) import Module import UniqFM import UniqSupply import Outputable import ErrUtils import Maybes import SrcLoc import DynFlags import Util import FastString import Control.Monad \end{code} This module takes IfaceDecl -> TyThing IfaceType -> Type etc An IfaceDecl is populated with RdrNames, and these are not renamed to Names before typechecking, because there should be no scope errors etc. -- For (b) consider: f = \$(...h....) -- where h is imported, and calls f via an hi-boot file. -- This is bad! But it is not seen as a staging error, because h -- is indeed imported. We don't want the type-checker to black-hole -- when simplifying and compiling the splice! -- -- Simple solution: discard any unfolding that mentions a variable -- bound in this module (and hence not yet processed). -- The discarding happens when forkM finds a type error. %************************************************************************ %* * %* tcImportDecl is the key function for "faulting in" * %* imported things %* * %************************************************************************ The main idea is this. We are chugging along type-checking source code, and find a reference to GHC.Base.map. We call tcLookupGlobal, which doesn't find it in the EPS type envt. So it 1 loads GHC.Base.hi 2 gets the decl for GHC.Base.map 3 typechecks it via tcIfaceDecl 4 and adds it to the type env in the EPS Note that DURING STEP 4, we may find that map's type mentions a type constructor that also Notice that for imported things we read the current version from the EPS mutable variable. This is important in situations like ...$(e1)...$(e2)... where the code that e1 expands to might import some defns that also turn out to be needed by the code that e2 expands to. \begin{code} tcImportDecl :: Name -> TcM TyThing -- Entry point for *source-code* uses of importDecl tcImportDecl name | Just thing <- wiredInNameTyThing_maybe name = do { when (needWiredInHomeIface thing) (initIfaceTcRn (loadWiredInHomeIface name)) -- See Note [Loading instances for wired-in things] ; return thing } | otherwise = do { traceIf (text "tcImportDecl" <+> ppr name) ; mb_thing <- initIfaceTcRn (importDecl name) ; case mb_thing of Succeeded thing -> return thing Failed err -> failWithTc err } importDecl :: Name -> IfM lcl (MaybeErr MsgDoc TyThing) -- Get the TyThing for this Name from an interface file -- It's not a wired-in thing -- the caller caught that importDecl name = ASSERT( not (isWiredInName name) ) do { traceIf nd_doc -- Load the interface, which should populate the PTE ; mb_iface <- ASSERT2( isExternalName name, ppr name ) loadInterface nd_doc (nameModule name) ImportBySystem ; case mb_iface of { Failed err_msg -> return (Failed err_msg) ; Succeeded _ -> do -- Now look it up again; this time we should find it { eps <- getEps ; case lookupTypeEnv (eps_PTE eps) name of Just thing -> return (Succeeded thing) Nothing -> return (Failed not_found_msg) }}} where nd_doc = ptext (sLit "Need decl for") <+> ppr name not_found_msg = hang (ptext (sLit "Can't find interface-file declaration for") <+> pprNameSpace (occNameSpace (nameOccName name)) <+> ppr name) 2 (vcat [ptext (sLit "Probable cause: bug in .hi-boot file, or inconsistent .hi file"), ptext (sLit "Use -ddump-if-trace to get an idea of which file caused the error")]) \end{code} %************************************************************************ %* * Checks for wired-in things %* * %************************************************************************ Note [Loading instances for wired-in things] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ We need to make sure that we have at least *read* the interface files for any module with an instance decl or RULE that we might want. * If the instance decl is an orphan, we have a whole separate mechanism (loadOprhanModules) * If the instance decl not an orphan, then the act of looking at the TyCon or Class will force in the defining module for the TyCon/Class, and hence the instance decl * BUT, if the TyCon is a wired-in TyCon, we don't really need its interface; but we must make sure we read its interface in case it has instances or rules. That is what LoadIface.loadWiredInHomeInterface does. It's called from TcIface.{tcImportDecl, checkWiredInTyCon, ifCheckWiredInThing} * HOWEVER, only do this for TyCons. There are no wired-in Classes. There are some wired-in Ids, but we don't want to load their interfaces. For example, Control.Exception.Base.recSelError is wired in, but that module is compiled late in the base library, and we don't want to force it to load before it's been compiled! All of this is done by the type checker. The renamer plays no role. (It used to, but no longer.) \begin{code} checkWiredInTyCon :: TyCon -> TcM () -- Ensure that the home module of the TyCon (and hence its instances) -- are loaded. See Note [Loading instances for wired-in things] -- It might not be a wired-in tycon (see the calls in TcUnify), -- in which case this is a no-op. checkWiredInTyCon tc | not (isWiredInName tc_name) = return () | otherwise = do { mod <- getModule ; ASSERT( isExternalName tc_name ) when (mod /= nameModule tc_name) (initIfaceTcRn (loadWiredInHomeIface tc_name)) -- Don't look for (non-existent) Float.hi when -- compiling Float.lhs, which mentions Float of course -- A bit yukky to call initIfaceTcRn here } where tc_name = tyConName tc ifCheckWiredInThing :: TyThing -> IfL () -- Even though we are in an interface file, we want to make -- sure the instances of a wired-in thing are loaded (imagine f :: Double -> Double) -- Ditto want to ensure that RULES are loaded too -- See Note [Loading instances for wired-in things] ifCheckWiredInThing thing = do { mod <- getIfModule -- Check whether we are typechecking the interface for this -- very module. E.g when compiling the base library in --make mode -- we may typecheck GHC.Base.hi. At that point, GHC.Base is not in -- the HPT, so without the test we'll demand-load it into the PIT! -- C.f. the same test in checkWiredInTyCon above ; let name = getName thing ; ASSERT2( isExternalName name, ppr name ) when (needWiredInHomeIface thing && mod /= nameModule name) (loadWiredInHomeIface name) } needWiredInHomeIface :: TyThing -> Bool -- Only for TyCons; see Note [Loading instances for wired-in things] needWiredInHomeIface (ATyCon {}) = True needWiredInHomeIface _ = False \end{code} %************************************************************************ %* * Type-checking a complete interface %* * %************************************************************************ Suppose we discover we don't need to recompile. Then we must type check the old interface file. This is a bit different to the incremental type checking we do as we suck in interface files. Instead we do things similarly as when we are typechecking source decls: we bring into scope the type envt for the interface all at once, using a knot. Remember, the decls aren't necessarily in dependency order -- and even if they were, the type decls might be mutually recursive. \begin{code} typecheckIface :: ModIface -- Get the decls from here -> TcRnIf gbl lcl ModDetails typecheckIface iface = initIfaceTc iface $ \ tc_env_var -> do -- The tc_env_var is freshly allocated, private to -- type-checking this particular interface { -- Get the right set of decls and rules. If we are compiling without -O -- we discard pragmas before typechecking, so that we don't "see" -- information that we shouldn't. From a versioning point of view -- It's not actually *wrong* to do so, but in fact GHCi is unable -- to handle unboxed tuples, so it must not see unfoldings. ignore_prags <- goptM Opt_IgnoreInterfacePragmas -- Typecheck the decls. This is done lazily, so that the knot-tying -- within this single module work out right. In the If monad there is -- no global envt for the current interface; instead, the knot is tied -- through the if_rec_types field of IfGblEnv ; names_w_things <- loadDecls ignore_prags (mi_decls iface) ; let type_env = mkNameEnv names_w_things ; writeMutVar tc_env_var type_env -- Now do those rules, instances and annotations ; insts <- mapM tcIfaceInst (mi_insts iface) ; fam_insts <- mapM tcIfaceFamInst (mi_fam_insts iface) ; rules <- tcIfaceRules ignore_prags (mi_rules iface) ; anns <- tcIfaceAnnotations (mi_anns iface) -- Vectorisation information ; vect_info <- tcIfaceVectInfo (mi_module iface) type_env (mi_vect_info iface) -- Exports ; exports <- ifaceExportNames (mi_exports iface) -- Finished ; traceIf (vcat [text "Finished typechecking interface for" <+> ppr (mi_module iface), text "Type envt:" <+> ppr type_env]) ; return $ ModDetails { md_types = type_env , md_insts = insts , md_fam_insts = fam_insts , md_rules = rules , md_anns = anns , md_vect_info = vect_info , md_exports = exports } } \end{code} %************************************************************************ %* * Type and class declarations %* * %************************************************************************ \begin{code} tcHiBootIface :: HscSource -> Module -> TcRn ModDetails -- Load the hi-boot iface for the module being compiled, -- if it indeed exists in the transitive closure of imports -- Return the ModDetails, empty if no hi-boot iface tcHiBootIface hsc_src mod | isHsBoot hsc_src -- Already compiling a hs-boot file = return emptyModDetails | otherwise = do { traceIf (text "loadHiBootInterface" <+> ppr mod) ; mode <- getGhcMode ; if not (isOneShot mode) -- In --make and interactive mode, if this module has an hs-boot file -- we'll have compiled it already, and it'll be in the HPT -- -- We check wheher the interface is a *boot* interface. -- It can happen (when using GHC from Visual Studio) that we -- compile a module in TypecheckOnly mode, with a stable, -- fully-populated HPT. In that case the boot interface isn't there -- (it's been replaced by the mother module) so we can't check it. -- And that's fine, because if M's ModInfo is in the HPT, then -- it's been compiled once, and we don't need to check the boot iface then do { hpt <- getHpt ; case lookupUFM hpt (moduleName mod) of Just info | mi_boot (hm_iface info) -> return (hm_details info) _ -> return emptyModDetails } else do -- OK, so we're in one-shot mode. -- In that case, we're read all the direct imports by now, -- so eps_is_boot will record if any of our imports mention us by -- way of hi-boot file { eps <- getEps ; case lookupUFM (eps_is_boot eps) (moduleName mod) of { Nothing -> return emptyModDetails ; -- The typical case Just (_, False) -> failWithTc moduleLoop ; -- Someone below us imported us! -- This is a loop with no hi-boot in the way Just (_mod, True) -> -- There's a hi-boot interface below us do { read_result <- findAndReadIface need mod True -- Hi-boot file ; case read_result of Failed err -> failWithTc (elaborate err) Succeeded (iface, _path) -> typecheckIface iface }}}} where need = ptext (sLit "Need the hi-boot interface for") <+> ppr mod <+> ptext (sLit "to compare against the Real Thing") moduleLoop = ptext (sLit "Circular imports: module") <+> quotes (ppr mod) <+> ptext (sLit "depends on itself") elaborate err = hang (ptext (sLit "Could not find hi-boot interface for") <+> quotes (ppr mod) <> colon) 4 err \end{code} %************************************************************************ %* * Type and class declarations %* * %************************************************************************ When typechecking a data type decl, we *lazily* (via forkM) typecheck the constructor argument types. This is in the hope that we may never poke on those argument types, and hence may never need to load the interface files for types mentioned in the arg types. E.g. data Foo.S = MkS Baz.T Mabye we can get away without even loading the interface for Baz! This is not just a performance thing. Suppose we have data Foo.S = MkS Baz.T data Baz.T = MkT Foo.S (in different interface files, of course). Now, first we load and typecheck Foo.S, and add it to the type envt. If we do explore MkS's argument, we'll load and typecheck Baz.T. If we explore MkT's argument we'll find Foo.S already in the envt. If we typechecked constructor args eagerly, when loading Foo.S we'd try to typecheck the type Baz.T. So we'd fault in Baz.T... and then need Foo.S... which isn't done yet. All very cunning. However, there is a rather subtle gotcha which bit me when developing this stuff. When we typecheck the decl for S, we extend the type envt with S, MkS, and all its implicit Ids. Suppose (a bug, but it happened) that the list of implicit Ids depended in turn on the constructor arg types. Then the following sequence of events takes place: * we build a thunk for the constructor arg tys * we build a thunk for the extended type environment (depends on ) * we write the extended type envt into the global EPS mutvar Now we look something up in the type envt * that pulls on * which reads the global type envt out of the global EPS mutvar * but that depends in turn on It's subtle, because, it'd work fine if we typechecked the constructor args eagerly -- they don't need the extended type envt. They just get the extended type envt by accident, because they look at it later. What this means is that the implicitTyThings MUST NOT DEPEND on any of the forkM stuff. \begin{code} tcIfaceDecl :: Bool -- True <=> discard IdInfo on IfaceId bindings -> IfaceDecl -> IfL TyThing tcIfaceDecl = tc_iface_decl NoParentTyCon tc_iface_decl :: TyConParent -- For nested declarations -> Bool -- True <=> discard IdInfo on IfaceId bindings -> IfaceDecl -> IfL TyThing tc_iface_decl _ ignore_prags (IfaceId {ifName = occ_name, ifType = iface_type, ifIdDetails = details, ifIdInfo = info}) = do { name <- lookupIfaceTop occ_name ; ty <- tcIfaceType iface_type ; details <- tcIdDetails ty details ; info <- tcIdInfo ignore_prags name ty info ; return (AnId (mkGlobalId details name ty info)) } tc_iface_decl parent _ (IfaceData {ifName = occ_name, ifCType = cType, ifTyVars = tv_bndrs, ifCtxt = ctxt, ifGadtSyntax = gadt_syn, ifCons = rdr_cons, ifRec = is_rec, ifAxiom = mb_axiom_name }) = bindIfaceTyVars_AT tv_bndrs $ \ tyvars -> do { tc_name <- lookupIfaceTop occ_name ; tycon <- fixM $ \ tycon -> do { stupid_theta <- tcIfaceCtxt ctxt ; parent' <- tc_parent tyvars mb_axiom_name ; cons <- tcIfaceDataCons tc_name tycon tyvars rdr_cons ; return (buildAlgTyCon tc_name tyvars cType stupid_theta cons is_rec gadt_syn parent') } ; traceIf (text "tcIfaceDecl4" <+> ppr tycon) ; return (ATyCon tycon) } where tc_parent :: [TyVar] -> Maybe Name -> IfL TyConParent tc_parent _ Nothing = return parent tc_parent tyvars (Just ax_name) = ASSERT( isNoParent parent ) do { ax <- tcIfaceCoAxiom ax_name ; let fam_tc = coAxiomTyCon ax ax_unbr = toUnbranchedAxiom ax -- data families don't have branches: branch = coAxiomSingleBranch ax_unbr ax_tvs = coAxBranchTyVars branch ax_lhs = coAxBranchLHS branch subst = zipTopTvSubst ax_tvs (mkTyVarTys tyvars) -- The subst matches the tyvar of the TyCon -- with those from the CoAxiom. They aren't -- necessarily the same, since the two may be -- gotten from separate interface-file declarations ; return (FamInstTyCon ax_unbr fam_tc (substTys subst ax_lhs)) } tc_iface_decl parent _ (IfaceSyn {ifName = occ_name, ifTyVars = tv_bndrs, ifSynRhs = mb_rhs_ty, ifSynKind = kind }) = bindIfaceTyVars_AT tv_bndrs $ \ tyvars -> do { tc_name <- lookupIfaceTop occ_name ; rhs_kind <- tcIfaceKind kind -- Note [Synonym kind loop] ; rhs <- forkM (mk_doc tc_name) $ tc_syn_rhs mb_rhs_ty ; tycon <- buildSynTyCon tc_name tyvars rhs rhs_kind parent ; return (ATyCon tycon) } where mk_doc n = ptext (sLit "Type syonym") <+> ppr n tc_syn_rhs (SynFamilyTyCon a b) = return (SynFamilyTyCon a b) tc_syn_rhs (SynonymTyCon ty) = do { rhs_ty <- tcIfaceType ty ; return (SynonymTyCon rhs_ty) } tc_iface_decl _parent ignore_prags (IfaceClass {ifCtxt = rdr_ctxt, ifName = tc_occ, ifTyVars = tv_bndrs, ifFDs = rdr_fds, ifATs = rdr_ats, ifSigs = rdr_sigs, ifRec = tc_isrec }) -- ToDo: in hs-boot files we should really treat abstract classes specially, -- as we do abstract tycons = bindIfaceTyVars tv_bndrs $ \ tyvars -> do { tc_name <- lookupIfaceTop tc_occ ; traceIf (text "tc-iface-class1" <+> ppr tc_occ) ; ctxt <- mapM tc_sc rdr_ctxt ; traceIf (text "tc-iface-class2" <+> ppr tc_occ) ; sigs <- mapM tc_sig rdr_sigs ; fds <- mapM tc_fd rdr_fds ; traceIf (text "tc-iface-class3" <+> ppr tc_occ) ; cls <- fixM $ \ cls -> do { ats <- mapM (tc_at cls) rdr_ats ; traceIf (text "tc-iface-class4" <+> ppr tc_occ) ; buildClass ignore_prags tc_name tyvars ctxt fds ats sigs tc_isrec } ; return (ATyCon (classTyCon cls)) } where tc_sc pred = forkM (mk_sc_doc pred) (tcIfaceType pred) -- The *length* of the superclasses is used by buildClass, and hence must -- not be inside the thunk. But the *content* maybe recursive and hence -- must be lazy (via forkM). Example: -- class C (T a) => D a where -- data T a -- Here the associated type T is knot-tied with the class, and -- so we must not pull on T too eagerly. See Trac #5970 mk_sc_doc pred = ptext (sLit "Superclass") <+> ppr pred tc_sig (IfaceClassOp occ dm rdr_ty) = do { op_name <- lookupIfaceTop occ ; op_ty <- forkM (mk_op_doc op_name rdr_ty) (tcIfaceType rdr_ty) -- Must be done lazily for just the same reason as the -- type of a data con; to avoid sucking in types that -- it mentions unless it's necessary to do so ; return (op_name, dm, op_ty) } tc_at cls (IfaceAT tc_decl defs_decls) = do ATyCon tc <- tc_iface_decl (AssocFamilyTyCon cls) ignore_prags tc_decl defs <- mapM tc_iface_at_def defs_decls return (tc, defs) tc_iface_at_def (IfaceATD tvs pat_tys ty) = bindIfaceTyVars_AT tvs $ \tvs' -> liftM2 (\pats tys -> ATD tvs' pats tys noSrcSpan) (mapM tcIfaceType pat_tys) (tcIfaceType ty) mk_op_doc op_name op_ty = ptext (sLit "Class op") <+> sep [ppr op_name, ppr op_ty] tc_fd (tvs1, tvs2) = do { tvs1' <- mapM tcIfaceTyVar tvs1 ; tvs2' <- mapM tcIfaceTyVar tvs2 ; return (tvs1', tvs2') } tc_iface_decl _ _ (IfaceForeign {ifName = rdr_name, ifExtName = ext_name}) = do { name <- lookupIfaceTop rdr_name ; return (ATyCon (mkForeignTyCon name ext_name liftedTypeKind 0)) } tc_iface_decl _ _ (IfaceAxiom {ifName = ax_occ, ifTyCon = tc, ifAxBranches = branches}) = do { tc_name <- lookupIfaceTop ax_occ ; tc_tycon <- tcIfaceTyCon tc ; tc_branches <- mapM tc_branch branches ; let axiom = CoAxiom { co_ax_unique = nameUnique tc_name , co_ax_name = tc_name , co_ax_tc = tc_tycon , co_ax_branches = toBranchList tc_branches , co_ax_implicit = False } ; return (ACoAxiom axiom) } where tc_branch :: IfaceAxBranch -> IfL CoAxBranch tc_branch (IfaceAxBranch { ifaxbTyVars = tv_bndrs, ifaxbLHS = lhs, ifaxbRHS = rhs }) = bindIfaceTyVars tv_bndrs $ \ tvs -> do { tc_lhs <- mapM tcIfaceType lhs ; tc_rhs <- tcIfaceType rhs ; let branch = CoAxBranch { cab_loc = noSrcSpan , cab_tvs = tvs , cab_lhs = tc_lhs , cab_rhs = tc_rhs } ; return branch } tcIfaceDataCons :: Name -> TyCon -> [TyVar] -> IfaceConDecls -> IfL AlgTyConRhs tcIfaceDataCons tycon_name tycon _ if_cons = case if_cons of IfAbstractTyCon dis -> return (AbstractTyCon dis) IfDataFamTyCon -> return DataFamilyTyCon IfDataTyCon cons -> do { data_cons <- mapM tc_con_decl cons ; return (mkDataTyConRhs data_cons) } IfNewTyCon con -> do { data_con <- tc_con_decl con ; mkNewTyConRhs tycon_name tycon data_con } where tc_con_decl (IfCon { ifConInfix = is_infix, ifConUnivTvs = univ_tvs, ifConExTvs = ex_tvs, ifConOcc = occ, ifConCtxt = ctxt, ifConEqSpec = spec, ifConArgTys = args, ifConFields = field_lbls, ifConStricts = if_stricts}) = bindIfaceTyVars univ_tvs $ \ univ_tyvars -> do bindIfaceTyVars ex_tvs $ \ ex_tyvars -> do { name <- lookupIfaceTop occ -- Read the context and argument types, but lazily for two reasons -- (a) to avoid looking tugging on a recursive use of -- the type itself, which is knot-tied -- (b) to avoid faulting in the component types unless -- they are really needed ; ~(eq_spec, theta, arg_tys) <- forkM (mk_doc name) $ do { eq_spec <- tcIfaceEqSpec spec ; theta <- tcIfaceCtxt ctxt ; arg_tys <- mapM tcIfaceType args ; return (eq_spec, theta, arg_tys) } ; lbl_names <- mapM lookupIfaceTop field_lbls ; stricts <- mapM tc_strict if_stricts -- Remember, tycon is the representation tycon ; let orig_res_ty = mkFamilyTyConApp tycon (substTyVars (mkTopTvSubst eq_spec) univ_tyvars) ; buildDataCon (pprPanic "tcIfaceDataCons: FamInstEnvs" (ppr name)) name is_infix stricts lbl_names univ_tyvars ex_tyvars eq_spec theta arg_tys orig_res_ty tycon } mk_doc con_name = ptext (sLit "Constructor") <+> ppr con_name tc_strict IfNoBang = return HsNoBang tc_strict IfStrict = return HsStrict tc_strict IfUnpack = return (HsUnpack Nothing) tc_strict (IfUnpackCo if_co) = do { co <- tcIfaceCo if_co ; return (HsUnpack (Just co)) } tcIfaceEqSpec :: [(OccName, IfaceType)] -> IfL [(TyVar, Type)] tcIfaceEqSpec spec = mapM do_item spec where do_item (occ, if_ty) = do { tv <- tcIfaceTyVar (occNameFS occ) ; ty <- tcIfaceType if_ty ; return (tv,ty) } \end{code} Note [Synonym kind loop] ~~~~~~~~~~~~~~~~~~~~~~~~ Notice that we eagerly grab the *kind* from the interface file, but build a forkM thunk for the *rhs* (and family stuff). To see why, consider this (Trac #2412) M.hs: module M where { import X; data T = MkT S } X.hs: module X where { import {-# SOURCE #-} M; type S = T } M.hs-boot: module M where { data T } When kind-checking M.hs we need S's kind. But we do not want to find S's kind from (typeKind S-rhs), because we don't want to look at S-rhs yet! Since S is imported from X.hi, S gets just one chance to be defined, and we must not do that until we've finished with M.T. Solution: record S's kind in the interface file; now we can safely look at it. %************************************************************************ %* * Instances %* * %************************************************************************ \begin{code} tcIfaceInst :: IfaceClsInst -> IfL ClsInst tcIfaceInst (IfaceClsInst { ifDFun = dfun_occ, ifOFlag = oflag , ifInstCls = cls, ifInstTys = mb_tcs }) = do { dfun <- forkM (ptext (sLit "Dict fun") <+> ppr dfun_occ) $ tcIfaceExtId dfun_occ ; let mb_tcs' = map (fmap ifaceTyConName) mb_tcs ; return (mkImportedInstance cls mb_tcs' dfun oflag) } tcIfaceFamInst :: IfaceFamInst -> IfL (FamInst Branched) tcIfaceFamInst (IfaceFamInst { ifFamInstFam = fam, ifFamInstTys = mb_tcss , ifFamInstGroup = group, ifFamInstAxiom = axiom_name } ) = do { axiom' <- forkM (ptext (sLit "Axiom") <+> ppr axiom_name) $ tcIfaceCoAxiom axiom_name ; let mb_tcss' = map (map (fmap ifaceTyConName)) mb_tcss ; return (mkImportedFamInst fam group mb_tcss' axiom') } \end{code} %************************************************************************ %* * Rules %* * %************************************************************************ We move a IfaceRule from eps_rules to eps_rule_base when all its LHS free vars are in the type environment. However, remember that typechecking a Rule may (as a side effect) augment the type envt, and so we may need to iterate the process. \begin{code} tcIfaceRules :: Bool -- True <=> ignore rules -> [IfaceRule] -> IfL [CoreRule] tcIfaceRules ignore_prags if_rules | ignore_prags = return [] | otherwise = mapM tcIfaceRule if_rules tcIfaceRule :: IfaceRule -> IfL CoreRule tcIfaceRule (IfaceRule {ifRuleName = name, ifActivation = act, ifRuleBndrs = bndrs, ifRuleHead = fn, ifRuleArgs = args, ifRuleRhs = rhs, ifRuleAuto = auto }) = do { ~(bndrs', args', rhs') <- -- Typecheck the payload lazily, in the hope it'll never be looked at forkM (ptext (sLit "Rule") <+> ftext name) $ bindIfaceBndrs bndrs $ \ bndrs' -> do { args' <- mapM tcIfaceExpr args ; rhs' <- tcIfaceExpr rhs ; return (bndrs', args', rhs') } ; let mb_tcs = map ifTopFreeName args ; return (Rule { ru_name = name, ru_fn = fn, ru_act = act, ru_bndrs = bndrs', ru_args = args', ru_rhs = occurAnalyseExpr rhs', ru_rough = mb_tcs, ru_auto = auto, ru_local = False }) } -- An imported RULE is never for a local Id -- or, even if it is (module loop, perhaps) -- we'll just leave it in the non-local set where -- This function *must* mirror exactly what Rules.topFreeName does -- We could have stored the ru_rough field in the iface file -- but that would be redundant, I think. -- The only wrinkle is that we must not be deceived by -- type syononyms at the top of a type arg. Since -- we can't tell at this point, we are careful not -- to write them out in coreRuleToIfaceRule ifTopFreeName :: IfaceExpr -> Maybe Name ifTopFreeName (IfaceType (IfaceTyConApp tc _ )) = Just (ifaceTyConName tc) ifTopFreeName (IfaceApp f _) = ifTopFreeName f ifTopFreeName (IfaceExt n) = Just n ifTopFreeName _ = Nothing \end{code} %************************************************************************ %* * Annotations %* * %************************************************************************ \begin{code} tcIfaceAnnotations :: [IfaceAnnotation] -> IfL [Annotation] tcIfaceAnnotations = mapM tcIfaceAnnotation tcIfaceAnnotation :: IfaceAnnotation -> IfL Annotation tcIfaceAnnotation (IfaceAnnotation target serialized) = do target' <- tcIfaceAnnTarget target return $ Annotation { ann_target = target', ann_value = serialized } tcIfaceAnnTarget :: IfaceAnnTarget -> IfL (AnnTarget Name) tcIfaceAnnTarget (NamedTarget occ) = do name <- lookupIfaceTop occ return $ NamedTarget name tcIfaceAnnTarget (ModuleTarget mod) = do return $ ModuleTarget mod \end{code} %************************************************************************ %* * Vectorisation information %* * %************************************************************************ \begin{code} -- We need access to the type environment as we need to look up information about type constructors -- (i.e., their data constructors and whether they are class type constructors). If a vectorised -- type constructor or class is defined in the same module as where it is vectorised, we cannot -- look that information up from the type constructor that we obtained via a 'forkM'ed -- 'tcIfaceTyCon' without recursively loading the interface that we are already type checking again -- and again and again... -- tcIfaceVectInfo :: Module -> TypeEnv -> IfaceVectInfo -> IfL VectInfo tcIfaceVectInfo mod typeEnv (IfaceVectInfo { ifaceVectInfoVar = vars , ifaceVectInfoTyCon = tycons , ifaceVectInfoTyConReuse = tyconsReuse , ifaceVectInfoScalarVars = scalarVars , ifaceVectInfoScalarTyCons = scalarTyCons }) = do { let scalarTyConsSet = mkNameSet scalarTyCons ; vVars <- mapM vectVarMapping vars ; let varsSet = mkVarSet (map fst vVars) ; tyConRes1 <- mapM (vectTyConVectMapping varsSet) tycons ; tyConRes2 <- mapM (vectTyConReuseMapping varsSet) tyconsReuse ; vScalarVars <- mapM vectVar scalarVars ; let (vTyCons, vDataCons, vScSels) = unzip3 (tyConRes1 ++ tyConRes2) ; return $ VectInfo { vectInfoVar = mkVarEnv vVars `extendVarEnvList` concat vScSels , vectInfoTyCon = mkNameEnv vTyCons , vectInfoDataCon = mkNameEnv (concat vDataCons) , vectInfoScalarVars = mkVarSet vScalarVars , vectInfoScalarTyCons = scalarTyConsSet } } where vectVarMapping name = do { vName <- lookupOrig mod (mkLocalisedOccName mod mkVectOcc name) ; var <- forkM (ptext (sLit "vect var") <+> ppr name) $ tcIfaceExtId name ; vVar <- forkM (ptext (sLit "vect vVar [mod =") <+> ppr mod <> ptext (sLit "; nameModule =") <+> ppr (nameModule name) <> ptext (sLit "]") <+> ppr vName) $ tcIfaceExtId vName ; return (var, (var, vVar)) } -- where -- lookupLocalOrExternalId name -- = do { let mb_id = lookupTypeEnv typeEnv name -- ; case mb_id of -- -- id is local -- Just (AnId id) -> return id -- -- name is not an Id => internal inconsistency -- Just _ -> notAnIdErr -- -- Id is external -- Nothing -> tcIfaceExtId name -- } -- -- notAnIdErr = pprPanic "TcIface.tcIfaceVectInfo: not an id" (ppr name) vectVar name = forkM (ptext (sLit "vect scalar var") <+> ppr name) $ tcIfaceExtId name vectTyConVectMapping vars name = do { vName <- lookupOrig mod (mkLocalisedOccName mod mkVectTyConOcc name) ; vectTyConMapping vars name vName } vectTyConReuseMapping vars name = vectTyConMapping vars name name vectTyConMapping vars name vName = do { tycon <- lookupLocalOrExternalTyCon name ; vTycon <- forkM (ptext (sLit "vTycon of") <+> ppr vName) $ lookupLocalOrExternalTyCon vName -- Map the data constructors of the original type constructor to those of the -- vectorised type constructor /unless/ the type constructor was vectorised -- abstractly; if it was vectorised abstractly, the workers of its data constructors -- do not appear in the set of vectorised variables. -- -- NB: This is lazy! We don't pull at the type constructors before we actually use -- the data constructor mapping. ; let isAbstract | isClassTyCon tycon = False | datacon:_ <- tyConDataCons tycon = not $ dataConWrapId datacon `elemVarSet` vars | otherwise = True vDataCons | isAbstract = [] | otherwise = [ (dataConName datacon, (datacon, vDatacon)) | (datacon, vDatacon) <- zip (tyConDataCons tycon) (tyConDataCons vTycon) ] -- Map the (implicit) superclass and methods selectors as they don't occur in -- the var map. vScSels | Just cls <- tyConClass_maybe tycon , Just vCls <- tyConClass_maybe vTycon = [ (sel, (sel, vSel)) | (sel, vSel) <- zip (classAllSelIds cls) (classAllSelIds vCls) ] | otherwise = [] ; return ( (name, (tycon, vTycon)) -- (T, T_v) , vDataCons -- list of (Ci, Ci_v) , vScSels -- list of (seli, seli_v) ) } where -- we need a fully defined version of the type constructor to be able to extract -- its data constructors etc. lookupLocalOrExternalTyCon name = do { let mb_tycon = lookupTypeEnv typeEnv name ; case mb_tycon of -- tycon is local Just (ATyCon tycon) -> return tycon -- name is not a tycon => internal inconsistency Just _ -> notATyConErr -- tycon is external Nothing -> tcIfaceTyCon (IfaceTc name) } notATyConErr = pprPanic "TcIface.tcIfaceVectInfo: not a tycon" (ppr name) \end{code} %************************************************************************ %* * Types %* * %************************************************************************ \begin{code} tcIfaceType :: IfaceType -> IfL Type tcIfaceType (IfaceTyVar n) = do { tv <- tcIfaceTyVar n; return (TyVarTy tv) } tcIfaceType (IfaceAppTy t1 t2) = do { t1' <- tcIfaceType t1; t2' <- tcIfaceType t2; return (AppTy t1' t2') } tcIfaceType (IfaceLitTy l) = do { l1 <- tcIfaceTyLit l; return (LitTy l1) } tcIfaceType (IfaceFunTy t1 t2) = do { t1' <- tcIfaceType t1; t2' <- tcIfaceType t2; return (FunTy t1' t2') } tcIfaceType (IfaceTyConApp tc tks) = do { tc' <- tcIfaceTyCon tc ; tks' <- tcIfaceTcArgs (tyConKind tc') tks ; return (mkTyConApp tc' tks') } tcIfaceType (IfaceForAllTy tv t) = bindIfaceTyVar tv $ \ tv' -> do { t' <- tcIfaceType t; return (ForAllTy tv' t') } tcIfaceType t@(IfaceCoConApp {}) = pprPanic "tcIfaceType" (ppr t) tcIfaceTypes :: [IfaceType] -> IfL [Type] tcIfaceTypes tys = mapM tcIfaceType tys tcIfaceTcArgs :: Kind -> [IfaceType] -> IfL [Type] tcIfaceTcArgs _ [] = return [] tcIfaceTcArgs kind (tk:tks) = case splitForAllTy_maybe kind of Nothing -> tcIfaceTypes (tk:tks) Just (_, kind') -> do { k' <- tcIfaceKind tk ; tks' <- tcIfaceTcArgs kind' tks ; return (k':tks') } ----------------------------------------- tcIfaceCtxt :: IfaceContext -> IfL ThetaType tcIfaceCtxt sts = mapM tcIfaceType sts ----------------------------------------- tcIfaceTyLit :: IfaceTyLit -> IfL TyLit tcIfaceTyLit (IfaceNumTyLit n) = return (NumTyLit n) tcIfaceTyLit (IfaceStrTyLit n) = return (StrTyLit n) ----------------------------------------- tcIfaceKind :: IfaceKind -> IfL Kind -- See Note [Checking IfaceTypes vs IfaceKinds] tcIfaceKind (IfaceTyVar n) = do { tv <- tcIfaceTyVar n; return (TyVarTy tv) } tcIfaceKind (IfaceAppTy t1 t2) = do { t1' <- tcIfaceKind t1; t2' <- tcIfaceKind t2; return (AppTy t1' t2') } tcIfaceKind (IfaceFunTy t1 t2) = do { t1' <- tcIfaceKind t1; t2' <- tcIfaceKind t2; return (FunTy t1' t2') } tcIfaceKind (IfaceTyConApp tc ts) = do { tc' <- tcIfaceKindCon tc; ts' <- tcIfaceKinds ts; return (mkTyConApp tc' ts') } tcIfaceKind (IfaceForAllTy tv t) = bindIfaceTyVar tv $ \ tv' -> do { t' <- tcIfaceKind t; return (ForAllTy tv' t') } tcIfaceKind t = pprPanic "tcIfaceKind" (ppr t) -- IfaceCoApp, IfaceLitTy tcIfaceKinds :: [IfaceKind] -> IfL [Kind] tcIfaceKinds tys = mapM tcIfaceKind tys \end{code} Note [Checking IfaceTypes vs IfaceKinds] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ We need to know whether we are checking a *type* or a *kind*. Consider module M where Proxy :: forall k. k -> * data T = T and consider the two IfaceTypes M.Proxy * M.T{tc} M.Proxy 'M.T{tc} 'M.T(d} The first is conventional, but in the latter we use the promoted type constructor (as a kind) and data constructor (as a type). However, the Name of the promoted type constructor is just M.T; it's the *same name* as the ordinary type constructor. We could add a "promoted" flag to an IfaceTyCon, but that's a bit heavy. Instead we use context to distinguish, as in the source language. - When checking a kind, we look up M.T{tc} and promote it - When checking a type, we look up M.T{tc} and don't promote it and M.T{d} and promote it See tcIfaceKindCon and tcIfaceKTyCon respectively This context business is why we need tcIfaceTcArgs. %************************************************************************ %* * Coercions %* * %************************************************************************ \begin{code} tcIfaceCo :: IfaceType -> IfL Coercion tcIfaceCo (IfaceTyVar n) = mkCoVarCo <$> tcIfaceCoVar n tcIfaceCo (IfaceAppTy t1 t2) = mkAppCo <$> tcIfaceCo t1 <*> tcIfaceCo t2 tcIfaceCo (IfaceFunTy t1 t2) = mkFunCo <$> tcIfaceCo t1 <*> tcIfaceCo t2 tcIfaceCo (IfaceTyConApp tc ts) = mkTyConAppCo <$> tcIfaceTyCon tc <*> mapM tcIfaceCo ts tcIfaceCo t@(IfaceLitTy _) = mkReflCo <$> tcIfaceType t tcIfaceCo (IfaceCoConApp tc ts) = tcIfaceCoApp tc ts tcIfaceCo (IfaceForAllTy tv t) = bindIfaceTyVar tv $ \ tv' -> mkForAllCo tv' <$> tcIfaceCo t tcIfaceCoApp :: IfaceCoCon -> [IfaceType] -> IfL Coercion tcIfaceCoApp IfaceReflCo [t] = Refl <$> tcIfaceType t tcIfaceCoApp (IfaceCoAx n i) ts = AxiomInstCo <$> tcIfaceCoAxiom n <*> pure i <*> mapM tcIfaceCo ts tcIfaceCoApp IfaceUnsafeCo [t1,t2] = UnsafeCo <$> tcIfaceType t1 <*> tcIfaceType t2 tcIfaceCoApp IfaceSymCo [t] = SymCo <$> tcIfaceCo t tcIfaceCoApp IfaceTransCo [t1,t2] = TransCo <$> tcIfaceCo t1 <*> tcIfaceCo t2 tcIfaceCoApp IfaceInstCo [t1,t2] = InstCo <$> tcIfaceCo t1 <*> tcIfaceType t2 tcIfaceCoApp (IfaceNthCo d) [t] = NthCo d <$> tcIfaceCo t tcIfaceCoApp (IfaceLRCo lr) [t] = LRCo lr <$> tcIfaceCo t tcIfaceCoApp cc ts = pprPanic "toIfaceCoApp" (ppr cc <+> ppr ts) tcIfaceCoVar :: FastString -> IfL CoVar tcIfaceCoVar = tcIfaceLclId \end{code} %************************************************************************ %* * Core %* * %************************************************************************ \begin{code} tcIfaceExpr :: IfaceExpr -> IfL CoreExpr tcIfaceExpr (IfaceType ty) = Type <$> tcIfaceType ty tcIfaceExpr (IfaceCo co) = Coercion <$> tcIfaceCo co tcIfaceExpr (IfaceCast expr co) = Cast <$> tcIfaceExpr expr <*> tcIfaceCo co tcIfaceExpr (IfaceLcl name) = Var <$> tcIfaceLclId name tcIfaceExpr (IfaceExt gbl) = Var <$> tcIfaceExtId gbl tcIfaceExpr (IfaceLit lit) = do lit' <- tcIfaceLit lit return (Lit lit') tcIfaceExpr (IfaceFCall cc ty) = do ty' <- tcIfaceType ty u <- newUnique dflags <- getDynFlags return (Var (mkFCallId dflags u cc ty')) tcIfaceExpr (IfaceTuple boxity args) = do args' <- mapM tcIfaceExpr args -- Put the missing type arguments back in let con_args = map (Type . exprType) args' ++ args' return (mkApps (Var con_id) con_args) where arity = length args con_id = dataConWorkId (tupleCon boxity arity) tcIfaceExpr (IfaceLam bndr body) = bindIfaceBndr bndr $ \bndr' -> Lam bndr' <$> tcIfaceExpr body tcIfaceExpr (IfaceApp fun arg) = App <$> tcIfaceExpr fun <*> tcIfaceExpr arg tcIfaceExpr (IfaceECase scrut ty) = do { scrut' <- tcIfaceExpr scrut ; ty' <- tcIfaceType ty ; return (castBottomExpr scrut' ty') } tcIfaceExpr (IfaceCase scrut case_bndr alts) = do scrut' <- tcIfaceExpr scrut case_bndr_name <- newIfaceName (mkVarOccFS case_bndr) let scrut_ty = exprType scrut' case_bndr' = mkLocalId case_bndr_name scrut_ty tc_app = splitTyConApp scrut_ty -- NB: Won't always succeed (polymoprhic case) -- but won't be demanded in those cases -- NB: not tcSplitTyConApp; we are looking at Core here -- look through non-rec newtypes to find the tycon that -- corresponds to the datacon in this case alternative extendIfaceIdEnv [case_bndr'] $ do alts' <- mapM (tcIfaceAlt scrut' tc_app) alts return (Case scrut' case_bndr' (coreAltsType alts') alts') tcIfaceExpr (IfaceLet (IfaceNonRec (IfLetBndr fs ty info) rhs) body) = do { name <- newIfaceName (mkVarOccFS fs) ; ty' <- tcIfaceType ty ; id_info <- tcIdInfo False {- Don't ignore prags; we are inside one! -} name ty' info ; let id = mkLocalIdWithInfo name ty' id_info ; rhs' <- tcIfaceExpr rhs ; body' <- extendIfaceIdEnv [id] (tcIfaceExpr body) ; return (Let (NonRec id rhs') body') } tcIfaceExpr (IfaceLet (IfaceRec pairs) body) = do { ids <- mapM tc_rec_bndr (map fst pairs) ; extendIfaceIdEnv ids $ do { pairs' <- zipWithM tc_pair pairs ids ; body' <- tcIfaceExpr body ; return (Let (Rec pairs') body') } } where tc_rec_bndr (IfLetBndr fs ty _) = do { name <- newIfaceName (mkVarOccFS fs) ; ty' <- tcIfaceType ty ; return (mkLocalId name ty') } tc_pair (IfLetBndr _ _ info, rhs) id = do { rhs' <- tcIfaceExpr rhs ; id_info <- tcIdInfo False {- Don't ignore prags; we are inside one! -} (idName id) (idType id) info ; return (setIdInfo id id_info, rhs') } tcIfaceExpr (IfaceTick tickish expr) = do expr' <- tcIfaceExpr expr tickish' <- tcIfaceTickish tickish return (Tick tickish' expr') ------------------------- tcIfaceTickish :: IfaceTickish -> IfM lcl (Tickish Id) tcIfaceTickish (IfaceHpcTick modl ix) = return (HpcTick modl ix) tcIfaceTickish (IfaceSCC cc tick push) = return (ProfNote cc tick push) ------------------------- tcIfaceLit :: Literal -> IfL Literal -- Integer literals deserialise to (LitInteger i ) -- so tcIfaceLit just fills in the type. -- See Note [Integer literals] in Literal tcIfaceLit (LitInteger i _) = do t <- tcIfaceTyCon (IfaceTc integerTyConName) return (mkLitInteger i (mkTyConTy t)) tcIfaceLit lit = return lit ------------------------- tcIfaceAlt :: CoreExpr -> (TyCon, [Type]) -> (IfaceConAlt, [FastString], IfaceExpr) -> IfL (AltCon, [TyVar], CoreExpr) tcIfaceAlt _ _ (IfaceDefault, names, rhs) = ASSERT( null names ) do rhs' <- tcIfaceExpr rhs return (DEFAULT, [], rhs') tcIfaceAlt _ _ (IfaceLitAlt lit, names, rhs) = ASSERT( null names ) do lit' <- tcIfaceLit lit rhs' <- tcIfaceExpr rhs return (LitAlt lit', [], rhs') -- A case alternative is made quite a bit more complicated -- by the fact that we omit type annotations because we can -- work them out. True enough, but its not that easy! tcIfaceAlt scrut (tycon, inst_tys) (IfaceDataAlt data_occ, arg_strs, rhs) = do { con <- tcIfaceDataCon data_occ ; when (debugIsOn && not (con `elem` tyConDataCons tycon)) (failIfM (ppr scrut $$ ppr con $$ ppr tycon $$ ppr (tyConDataCons tycon))) ; tcIfaceDataAlt con inst_tys arg_strs rhs } tcIfaceDataAlt :: DataCon -> [Type] -> [FastString] -> IfaceExpr -> IfL (AltCon, [TyVar], CoreExpr) tcIfaceDataAlt con inst_tys arg_strs rhs = do { us <- newUniqueSupply ; let uniqs = uniqsFromSupply us ; let (ex_tvs, arg_ids) = dataConRepFSInstPat arg_strs uniqs con inst_tys ; rhs' <- extendIfaceTyVarEnv ex_tvs $ extendIfaceIdEnv arg_ids $ tcIfaceExpr rhs ; return (DataAlt con, ex_tvs ++ arg_ids, rhs') } \end{code} \begin{code} tcExtCoreBindings :: [IfaceBinding] -> IfL CoreProgram -- Used for external core tcExtCoreBindings [] = return [] tcExtCoreBindings (b:bs) = do_one b (tcExtCoreBindings bs) do_one :: IfaceBinding -> IfL [CoreBind] -> IfL [CoreBind] do_one (IfaceNonRec bndr rhs) thing_inside = do { rhs' <- tcIfaceExpr rhs ; bndr' <- newExtCoreBndr bndr ; extendIfaceIdEnv [bndr'] $ do { core_binds <- thing_inside ; return (NonRec bndr' rhs' : core_binds) }} do_one (IfaceRec pairs) thing_inside = do { bndrs' <- mapM newExtCoreBndr bndrs ; extendIfaceIdEnv bndrs' $ do { rhss' <- mapM tcIfaceExpr rhss ; core_binds <- thing_inside ; return (Rec (bndrs' `zip` rhss') : core_binds) }} where (bndrs,rhss) = unzip pairs \end{code} %************************************************************************ %* * IdInfo %* * %************************************************************************ \begin{code} tcIdDetails :: Type -> IfaceIdDetails -> IfL IdDetails tcIdDetails _ IfVanillaId = return VanillaId tcIdDetails ty (IfDFunId ns) = return (DFunId ns (isNewTyCon (classTyCon cls))) where (_, _, cls, _) = tcSplitDFunTy ty tcIdDetails _ (IfRecSelId tc naughty) = do { tc' <- tcIfaceTyCon tc ; return (RecSelId { sel_tycon = tc', sel_naughty = naughty }) } tcIdInfo :: Bool -> Name -> Type -> IfaceIdInfo -> IfL IdInfo tcIdInfo ignore_prags name ty info | ignore_prags = return vanillaIdInfo | otherwise = case info of NoInfo -> return vanillaIdInfo HasInfo info -> foldlM tcPrag init_info info where -- Set the CgInfo to something sensible but uninformative before -- we start; default assumption is that it has CAFs init_info = vanillaIdInfo tcPrag :: IdInfo -> IfaceInfoItem -> IfL IdInfo tcPrag info HsNoCafRefs = return (info `setCafInfo` NoCafRefs) tcPrag info (HsArity arity) = return (info `setArityInfo` arity) tcPrag info (HsStrictness str) = return (info `setStrictnessInfo` Just str) tcPrag info (HsInline prag) = return (info `setInlinePragInfo` prag) -- The next two are lazy, so they don't transitively suck stuff in tcPrag info (HsUnfold lb if_unf) = do { unf <- tcUnfolding name ty info if_unf ; let info1 | lb = info `setOccInfo` strongLoopBreaker | otherwise = info ; return (info1 `setUnfoldingInfoLazily` unf) } \end{code} \begin{code} tcUnfolding :: Name -> Type -> IdInfo -> IfaceUnfolding -> IfL Unfolding tcUnfolding name _ info (IfCoreUnfold stable if_expr) = do { dflags <- getDynFlags ; mb_expr <- tcPragExpr name if_expr ; let unf_src = if stable then InlineStable else InlineRhs ; return (case mb_expr of Nothing -> NoUnfolding Just expr -> mkUnfolding dflags unf_src True {- Top level -} is_bottoming expr) } where -- Strictness should occur before unfolding! is_bottoming = case strictnessInfo info of Just sig -> isBottomingSig sig Nothing -> False tcUnfolding name _ _ (IfCompulsory if_expr) = do { mb_expr <- tcPragExpr name if_expr ; return (case mb_expr of Nothing -> NoUnfolding Just expr -> mkCompulsoryUnfolding expr) } tcUnfolding name _ _ (IfInlineRule arity unsat_ok boring_ok if_expr) = do { mb_expr <- tcPragExpr name if_expr ; return (case mb_expr of Nothing -> NoUnfolding Just expr -> mkCoreUnfolding InlineStable True expr arity (UnfWhen unsat_ok boring_ok)) } tcUnfolding name dfun_ty _ (IfDFunUnfold ops) = do { mb_ops1 <- forkM_maybe doc $ mapM tc_arg ops ; return (case mb_ops1 of Nothing -> noUnfolding Just ops1 -> mkDFunUnfolding dfun_ty ops1) } where doc = text "Class ops for dfun" <+> ppr name tc_arg (DFunPolyArg e) = do { e' <- tcIfaceExpr e; return (DFunPolyArg e') } tc_arg (DFunLamArg i) = return (DFunLamArg i) tcUnfolding name ty info (IfExtWrapper arity wkr) = tcIfaceWrapper name ty info arity (tcIfaceExtId wkr) tcUnfolding name ty info (IfLclWrapper arity wkr) = tcIfaceWrapper name ty info arity (tcIfaceLclId wkr) ------------- tcIfaceWrapper :: Name -> Type -> IdInfo -> Arity -> IfL Id -> IfL Unfolding tcIfaceWrapper name ty info arity get_worker = do { mb_wkr_id <- forkM_maybe doc get_worker ; us <- newUniqueSupply ; dflags <- getDynFlags ; return (case mb_wkr_id of Nothing -> noUnfolding Just wkr_id -> make_inline_rule dflags wkr_id us) } where doc = text "Worker for" <+> ppr name make_inline_rule dflags wkr_id us = mkWwInlineRule wkr_id (initUs_ us (mkWrapper dflags ty strict_sig) wkr_id) arity -- Again we rely here on strictness info always appearing -- before unfolding strict_sig = case strictnessInfo info of Just sig -> sig Nothing -> pprPanic "Worker info but no strictness for" (ppr name) \end{code} For unfoldings we try to do the job lazily, so that we never type check an unfolding that isn't going to be looked at. \begin{code} tcPragExpr :: Name -> IfaceExpr -> IfL (Maybe CoreExpr) tcPragExpr name expr = forkM_maybe doc $ do core_expr' <- tcIfaceExpr expr -- Check for type consistency in the unfolding whenGOptM Opt_DoCoreLinting $ do in_scope <- get_in_scope case lintUnfolding noSrcLoc in_scope core_expr' of Nothing -> return () Just fail_msg -> do { mod <- getIfModule ; pprPanic "Iface Lint failure" (vcat [ ptext (sLit "In interface for") <+> ppr mod , hang doc 2 fail_msg , ppr name <+> equals <+> ppr core_expr' , ptext (sLit "Iface expr =") <+> ppr expr ]) } return core_expr' where doc = text "Unfolding of" <+> ppr name get_in_scope :: IfL [Var] -- Totally disgusting; but just for linting get_in_scope = do { (gbl_env, lcl_env) <- getEnvs ; rec_ids <- case if_rec_types gbl_env of Nothing -> return [] Just (_, get_env) -> do { type_env <- setLclEnv () get_env ; return (typeEnvIds type_env) } ; return (varEnvElts (if_tv_env lcl_env) ++ varEnvElts (if_id_env lcl_env) ++ rec_ids) } \end{code} %************************************************************************ %* * Getting from Names to TyThings %* * %************************************************************************ \begin{code} tcIfaceGlobal :: Name -> IfL TyThing tcIfaceGlobal name | Just thing <- wiredInNameTyThing_maybe name -- Wired-in things include TyCons, DataCons, and Ids -- Even though we are in an interface file, we want to make -- sure the instances and RULES of this thing (particularly TyCon) are loaded -- Imagine: f :: Double -> Double = do { ifCheckWiredInThing thing; return thing } | otherwise = do { env <- getGblEnv ; case if_rec_types env of { -- Note [Tying the knot] Just (mod, get_type_env) | nameIsLocalOrFrom mod name -> do -- It's defined in the module being compiled { type_env <- setLclEnv () get_type_env -- yuk ; case lookupNameEnv type_env name of Just thing -> return thing Nothing -> pprPanic "tcIfaceGlobal (local): not found:" (ppr name $$ ppr type_env) } ; _ -> do { hsc_env <- getTopEnv ; mb_thing <- liftIO (lookupTypeHscEnv hsc_env name) ; case mb_thing of { Just thing -> return thing ; Nothing -> do { mb_thing <- importDecl name -- It's imported; go get it ; case mb_thing of Failed err -> failIfM err Succeeded thing -> return thing }}}}} -- Note [Tying the knot] -- ~~~~~~~~~~~~~~~~~~~~~ -- The if_rec_types field is used in two situations: -- -- a) Compiling M.hs, which indiretly imports Foo.hi, which mentions M.T -- Then we look up M.T in M's type environment, which is splatted into if_rec_types -- after we've built M's type envt. -- -- b) In ghc --make, during the upsweep, we encounter M.hs, whose interface M.hi -- is up to date. So we call typecheckIface on M.hi. This splats M.T into -- if_rec_types so that the (lazily typechecked) decls see all the other decls -- -- In case (b) it's important to do the if_rec_types check *before* looking in the HPT -- Because if M.hs also has M.hs-boot, M.T will *already be* in the HPT, but in its -- emasculated form (e.g. lacking data constructors). tcIfaceTyCon :: IfaceTyCon -> IfL TyCon tcIfaceTyCon (IfaceTc name) = do { thing <- tcIfaceGlobal name ; case thing of -- A "type constructor" can be a promoted data constructor -- c.f. Trac #5881 ATyCon tc -> return tc ADataCon dc -> return (promoteDataCon dc) _ -> pprPanic "tcIfaceTyCon" (ppr name $$ ppr thing) } tcIfaceKindCon :: IfaceTyCon -> IfL TyCon tcIfaceKindCon (IfaceTc name) = do { thing <- tcIfaceGlobal name ; case thing of -- A "type constructor" here is a promoted type constructor -- c.f. Trac #5881 ATyCon tc | isSuperKind (tyConKind tc) -> return tc -- Mainly just '*' or 'AnyK' | otherwise -> return (promoteTyCon tc) _ -> pprPanic "tcIfaceKindCon" (ppr name $$ ppr thing) } tcIfaceCoAxiom :: Name -> IfL (CoAxiom Branched) tcIfaceCoAxiom name = do { thing <- tcIfaceGlobal name ; return (tyThingCoAxiom thing) } tcIfaceDataCon :: Name -> IfL DataCon tcIfaceDataCon name = do { thing <- tcIfaceGlobal name ; case thing of ADataCon dc -> return dc _ -> pprPanic "tcIfaceExtDC" (ppr name$$ ppr thing) } tcIfaceExtId :: Name -> IfL Id tcIfaceExtId name = do { thing <- tcIfaceGlobal name ; case thing of AnId id -> return id _ -> pprPanic "tcIfaceExtId" (ppr name$$ ppr thing) } \end{code} %************************************************************************ %* * Bindings %* * %************************************************************************ \begin{code} bindIfaceBndr :: IfaceBndr -> (CoreBndr -> IfL a) -> IfL a bindIfaceBndr (IfaceIdBndr (fs, ty)) thing_inside = do { name <- newIfaceName (mkVarOccFS fs) ; ty' <- tcIfaceType ty ; let id = mkLocalId name ty' ; extendIfaceIdEnv [id] (thing_inside id) } bindIfaceBndr (IfaceTvBndr bndr) thing_inside = bindIfaceTyVar bndr thing_inside bindIfaceBndrs :: [IfaceBndr] -> ([CoreBndr] -> IfL a) -> IfL a bindIfaceBndrs [] thing_inside = thing_inside [] bindIfaceBndrs (b:bs) thing_inside = bindIfaceBndr b $ \ b' -> bindIfaceBndrs bs $ \ bs' -> thing_inside (b':bs') ----------------------- newExtCoreBndr :: IfaceLetBndr -> IfL Id newExtCoreBndr (IfLetBndr var ty _) -- Ignoring IdInfo for now = do { mod <- getIfModule ; name <- newGlobalBinder mod (mkVarOccFS var) noSrcSpan ; ty' <- tcIfaceType ty ; return (mkLocalId name ty') } ----------------------- bindIfaceTyVar :: IfaceTvBndr -> (TyVar -> IfL a) -> IfL a bindIfaceTyVar (occ,kind) thing_inside = do { name <- newIfaceName (mkTyVarOccFS occ) ; tyvar <- mk_iface_tyvar name kind ; extendIfaceTyVarEnv [tyvar] (thing_inside tyvar) } bindIfaceTyVars :: [IfaceTvBndr] -> ([TyVar] -> IfL a) -> IfL a bindIfaceTyVars bndrs thing_inside = do { names <- newIfaceNames (map mkTyVarOccFS occs) ; let (kis_kind, tys_kind) = span isSuperIfaceKind kinds (kis_name, tys_name) = splitAt (length kis_kind) names -- We need to bring the kind variables in scope since type -- variables may mention them. ; kvs <- zipWithM mk_iface_tyvar kis_name kis_kind ; extendIfaceTyVarEnv kvs $ do { tvs <- zipWithM mk_iface_tyvar tys_name tys_kind ; extendIfaceTyVarEnv tvs (thing_inside (kvs ++ tvs)) } } where (occs,kinds) = unzip bndrs isSuperIfaceKind :: IfaceKind -> Bool isSuperIfaceKind (IfaceTyConApp (IfaceTc n) []) = n == superKindTyConName isSuperIfaceKind _ = False mk_iface_tyvar :: Name -> IfaceKind -> IfL TyVar mk_iface_tyvar name ifKind = do { kind <- tcIfaceKind ifKind ; return (Var.mkTyVar name kind) } bindIfaceTyVars_AT :: [IfaceTvBndr] -> ([TyVar] -> IfL a) -> IfL a -- Used for type variable in nested associated data/type declarations -- where some of the type variables are already in scope -- class C a where { data T a b } -- Here 'a' is in scope when we look at the 'data T' bindIfaceTyVars_AT [] thing_inside = thing_inside [] bindIfaceTyVars_AT (b@(tv_occ,_) : bs) thing_inside = do { mb_tv <- lookupIfaceTyVar tv_occ ; let bind_b :: (TyVar -> IfL a) -> IfL a bind_b = case mb_tv of Just b' -> \k -> k b' Nothing -> bindIfaceTyVar b ; bind_b $ \b' -> bindIfaceTyVars_AT bs $ \bs' -> thing_inside (b':bs') } \end{code}