% % (c) The University of Glasgow 2006 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998 % \section[TcModule]{Typechecking a whole module} \begin{code} module TcRnDriver ( #ifdef GHCI tcRnStmt, tcRnExpr, tcRnType, tcRnLookupRdrName, tcRnLookupName, tcRnGetInfo, getModuleExports, tcRnRecoverDataCon, #endif tcRnModule, tcTopSrcDecls, tcRnExtCore ) where #include "HsVersions.h" import IO #ifdef GHCI import {-# SOURCE #-} TcSplice ( tcSpliceDecls ) #endif import DynFlags import StaticFlags import HsSyn import RdrHsSyn import PrelNames import RdrName import TcHsSyn import TcExpr import TcRnMonad import TcType import Inst import FamInst import InstEnv import FamInstEnv import TcBinds import TcDefaults import TcEnv import TcRules import TcForeign import TcInstDcls import TcIface import MkIface import IfaceSyn import TcSimplify import TcTyClsDecls import LoadIface import RnNames import RnEnv import RnSource import RnHsDoc import PprCore import CoreSyn import ErrUtils import Id import Var import Module import UniqFM import Name import NameEnv import NameSet import TyCon import SrcLoc import HscTypes import ListSetOps import Outputable import Breakpoints import TysWiredIn #ifdef GHCI import Linker import TcHsType import TcMType import TcMatches import TcGadt import RnTypes import RnExpr import IfaceEnv import MkId import IdInfo import {- Kind parts of -} Type import BasicTypes #endif import FastString import Maybes import Util import Bag import Control.Monad ( unless ) \end{code} %************************************************************************ %* * Typecheck and rename a module %* * %************************************************************************ \begin{code} tcRnModule :: HscEnv -> HscSource -> Bool -- True <=> save renamed syntax -> Located (HsModule RdrName) -> IO (Messages, Maybe TcGblEnv) tcRnModule hsc_env hsc_src save_rn_syntax (L loc (HsModule maybe_mod export_ies import_decls local_decls mod_deprec _ module_info maybe_doc)) = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ; let { this_pkg = thisPackage (hsc_dflags hsc_env) ; this_mod = case maybe_mod of Nothing -> mAIN -- 'module M where' is omitted Just (L _ mod) -> mkModule this_pkg mod } ; -- The normal case initTc hsc_env hsc_src save_rn_syntax this_mod $ setSrcSpan loc $ do { -- Deal with imports; tcg_env <- tcRnImports hsc_env this_mod import_decls ; setGblEnv tcg_env $ do { -- Load the hi-boot interface for this module, if any -- We do this now so that the boot_names can be passed -- to tcTyAndClassDecls, because the boot_names are -- automatically considered to be loop breakers -- -- Do this *after* tcRnImports, so that we know whether -- a module that we import imports us; and hence whether to -- look for a hi-boot file boot_iface <- tcHiBootIface hsc_src this_mod ; -- Rename and type check the declarations traceRn (text "rn1a") ; tcg_env <- if isHsBoot hsc_src then tcRnHsBootDecls local_decls else tcRnSrcDecls boot_iface local_decls ; setGblEnv tcg_env $ do { -- Report the use of any deprecated things -- We do this *before* processsing the export list so -- that we don't bleat about re-exporting a deprecated -- thing (especially via 'module Foo' export item) -- That is, only uses in the *body* of the module are complained about traceRn (text "rn3") ; failIfErrsM ; -- finishDeprecations crashes sometimes -- as a result of typechecker repairs (e.g. unboundNames) tcg_env <- finishDeprecations (hsc_dflags hsc_env) mod_deprec tcg_env ; -- Process the export list tcg_env <- rnExports (isJust maybe_mod) export_ies tcg_env ; traceRn (text "rn4") ; -- Compare the hi-boot iface (if any) with the real thing -- Must be done after processing the exports tcg_env <- checkHiBootIface tcg_env boot_iface ; -- Make the new type env available to stuff slurped from interface files -- Must do this after checkHiBootIface, because the latter might add new -- bindings for boot_dfuns, which may be mentioned in imported unfoldings writeMutVar (tcg_type_env_var tcg_env) (tcg_type_env tcg_env) ; -- Rename the Haddock documentation tcg_env <- rnHaddock module_info maybe_doc tcg_env ; -- Report unused names reportUnusedNames export_ies tcg_env ; -- Dump output and return tcDump tcg_env ; return tcg_env }}}} \end{code} %************************************************************************ %* * Import declarations %* * %************************************************************************ \begin{code} tcRnImports :: HscEnv -> Module -> [LImportDecl RdrName] -> TcM TcGblEnv tcRnImports hsc_env this_mod import_decls = do { (rn_imports, rdr_env, imports) <- rnImports import_decls ; ; let { dep_mods :: ModuleNameEnv (ModuleName, IsBootInterface) ; dep_mods = imp_dep_mods imports -- We want instance declarations from all home-package -- modules below this one, including boot modules, except -- ourselves. The 'except ourselves' is so that we don't -- get the instances from this module's hs-boot file ; want_instances :: ModuleName -> Bool ; want_instances mod = mod `elemUFM` dep_mods && mod /= moduleName this_mod ; home_insts = hptInstances hsc_env want_instances } ; -- Record boot-file info in the EPS, so that it's -- visible to loadHiBootInterface in tcRnSrcDecls, -- and any other incrementally-performed imports ; updateEps_ (\eps -> eps { eps_is_boot = dep_mods }) ; -- Update the gbl env ; updGblEnv ( \ gbl -> gbl { tcg_rdr_env = plusOccEnv (tcg_rdr_env gbl) rdr_env, tcg_imports = tcg_imports gbl `plusImportAvails` imports, tcg_rn_imports = fmap (const rn_imports) (tcg_rn_imports gbl), tcg_inst_env = extendInstEnvList (tcg_inst_env gbl) home_insts }) $ do { ; traceRn (text "rn1" <+> ppr (imp_dep_mods imports)) -- Fail if there are any errors so far -- The error printing (if needed) takes advantage -- of the tcg_env we have now set -- ; traceIf (text "rdr_env: " <+> ppr rdr_env) ; failIfErrsM -- Load any orphan-module and family instance-module -- interfaces, so that their rules and instance decls will be -- found. ; loadOrphanModules (imp_orphs imports) False ; loadOrphanModules (imp_finsts imports) True -- Check type-familily consistency ; traceRn (text "rn1: checking family instance consistency") ; let { dir_imp_mods = map (\ (mod, _, _) -> mod) . moduleEnvElts . imp_mods $ imports } ; checkFamInstConsistency (imp_finsts imports) dir_imp_mods ; ; getGblEnv } } \end{code} %************************************************************************ %* * Type-checking external-core modules %* * %************************************************************************ \begin{code} tcRnExtCore :: HscEnv -> HsExtCore RdrName -> IO (Messages, Maybe ModGuts) -- Nothing => some error occurred tcRnExtCore hsc_env (HsExtCore this_mod decls src_binds) -- The decls are IfaceDecls; all names are original names = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ; initTc hsc_env ExtCoreFile False this_mod $ do { let { ldecls = map noLoc decls } ; -- Deal with the type declarations; first bring their stuff -- into scope, then rname them, then type check them tcg_env <- importsFromLocalDecls (mkFakeGroup ldecls) ; setGblEnv tcg_env $ do { rn_decls <- rnTyClDecls ldecls ; failIfErrsM ; -- Dump trace of renaming part rnDump (ppr rn_decls) ; -- Typecheck them all together so that -- any mutually recursive types are done right tcg_env <- checkNoErrs (tcTyAndClassDecls emptyModDetails rn_decls) ; -- Make the new type env available to stuff slurped from interface files setGblEnv tcg_env $ do { -- Now the core bindings core_binds <- initIfaceExtCore (tcExtCoreBindings src_binds) ; -- Wrap up let { bndrs = bindersOfBinds core_binds ; my_exports = map (Avail . idName) bndrs ; -- ToDo: export the data types also? final_type_env = extendTypeEnvWithIds (tcg_type_env tcg_env) bndrs ; mod_guts = ModGuts { mg_module = this_mod, mg_boot = False, mg_usages = [], -- ToDo: compute usage mg_dir_imps = [], -- ?? mg_deps = noDependencies, -- ?? mg_exports = my_exports, mg_types = final_type_env, mg_insts = tcg_insts tcg_env, mg_fam_insts = tcg_fam_insts tcg_env, mg_fam_inst_env = tcg_fam_inst_env tcg_env, mg_rules = [], mg_binds = core_binds, -- Stubs mg_rdr_env = emptyGlobalRdrEnv, mg_fix_env = emptyFixityEnv, mg_deprecs = NoDeprecs, mg_foreign = NoStubs, mg_hpc_info = noHpcInfo, mg_dbg_sites = noDbgSites } } ; tcCoreDump mod_guts ; return mod_guts }}}} mkFakeGroup decls -- Rather clumsy; lots of unused fields = emptyRdrGroup { hs_tyclds = decls } \end{code} %************************************************************************ %* * Type-checking the top level of a module %* * %************************************************************************ \begin{code} tcRnSrcDecls :: ModDetails -> [LHsDecl RdrName] -> TcM TcGblEnv -- Returns the variables free in the decls -- Reason: solely to report unused imports and bindings tcRnSrcDecls boot_iface decls = do { -- Do all the declarations (tc_envs, lie) <- getLIE $ tc_rn_src_decls boot_iface decls ; -- Finish simplifying class constraints -- -- tcSimplifyTop deals with constant or ambiguous InstIds. -- How could there be ambiguous ones? They can only arise if a -- top-level decl falls under the monomorphism restriction -- and no subsequent decl instantiates its type. -- -- We do this after checkMain, so that we use the type info -- thaat checkMain adds -- -- We do it with both global and local env in scope: -- * the global env exposes the instances to tcSimplifyTop -- * the local env exposes the local Ids to tcSimplifyTop, -- so that we get better error messages (monomorphism restriction) traceTc (text "Tc8") ; inst_binds <- setEnvs tc_envs (tcSimplifyTop lie) ; -- Backsubstitution. This must be done last. -- Even tcSimplifyTop may do some unification. traceTc (text "Tc9") ; let { (tcg_env, _) = tc_envs ; TcGblEnv { tcg_type_env = type_env, tcg_binds = binds, tcg_rules = rules, tcg_fords = fords } = tcg_env ; all_binds = binds `unionBags` inst_binds } ; (bind_ids, binds', fords', rules') <- zonkTopDecls all_binds rules fords ; let { final_type_env = extendTypeEnvWithIds type_env bind_ids ; tcg_env' = tcg_env { tcg_type_env = final_type_env, tcg_binds = binds', tcg_rules = rules', tcg_fords = fords' } } ; return (tcg_env' { tcg_binds = tcg_binds tcg_env' }) } tc_rn_src_decls :: ModDetails -> [LHsDecl RdrName] -> TcM (TcGblEnv, TcLclEnv) -- Loops around dealing with each top level inter-splice group -- in turn, until it's dealt with the entire module tc_rn_src_decls boot_details ds = do { let { (first_group, group_tail) = findSplice ds } ; -- If ds is [] we get ([], Nothing) -- Deal with decls up to, but not including, the first splice (tcg_env, rn_decls) <- checkNoErrs $ rnTopSrcDecls first_group ; -- checkNoErrs: stop if renaming fails (tcg_env, tcl_env) <- setGblEnv tcg_env $ tcTopSrcDecls boot_details rn_decls ; -- If there is no splice, we're nearly done setEnvs (tcg_env, tcl_env) $ case group_tail of { Nothing -> do { tcg_env <- checkMain ; -- Check for `main' return (tcg_env, tcl_env) } ; -- If there's a splice, we must carry on Just (SpliceDecl splice_expr, rest_ds) -> do { #ifndef GHCI failWithTc (text "Can't do a top-level splice; need a bootstrapped compiler") #else -- Rename the splice expression, and get its supporting decls (rn_splice_expr, splice_fvs) <- checkNoErrs (rnLExpr splice_expr) ; -- checkNoErrs: don't typecheck if renaming failed rnDump (ppr rn_splice_expr) ; -- Execute the splice spliced_decls <- tcSpliceDecls rn_splice_expr ; -- Glue them on the front of the remaining decls and loop setGblEnv (tcg_env `addTcgDUs` usesOnly splice_fvs) $ tc_rn_src_decls boot_details (spliced_decls ++ rest_ds) #endif /* GHCI */ } } } \end{code} %************************************************************************ %* * Compiling hs-boot source files, and comparing the hi-boot interface with the real thing %* * %************************************************************************ \begin{code} tcRnHsBootDecls :: [LHsDecl RdrName] -> TcM TcGblEnv tcRnHsBootDecls decls = do { let { (first_group, group_tail) = findSplice decls } ; case group_tail of Just stuff -> spliceInHsBootErr stuff Nothing -> return () -- Rename the declarations ; (tcg_env, rn_group) <- rnTopSrcDecls first_group ; setGblEnv tcg_env $ do { -- Todo: check no foreign decls, no rules, no default decls -- Typecheck type/class decls ; traceTc (text "Tc2") ; let tycl_decls = hs_tyclds rn_group ; tcg_env <- checkNoErrs (tcTyAndClassDecls emptyModDetails tycl_decls) ; setGblEnv tcg_env $ do { -- Typecheck instance decls ; traceTc (text "Tc3") ; (tcg_env, inst_infos, _deriv_binds) <- tcInstDecls1 tycl_decls (hs_instds rn_group) (hs_derivds rn_group) ; setGblEnv tcg_env $ do { -- Typecheck value declarations ; traceTc (text "Tc5") ; val_ids <- tcHsBootSigs (hs_valds rn_group) -- Wrap up -- No simplification or zonking to do ; traceTc (text "Tc7a") ; gbl_env <- getGblEnv -- Make the final type-env -- Include the dfun_ids so that their type sigs -- are written into the interface file ; let { type_env0 = tcg_type_env gbl_env ; type_env1 = extendTypeEnvWithIds type_env0 val_ids ; type_env2 = extendTypeEnvWithIds type_env1 dfun_ids ; dfun_ids = map iDFunId inst_infos } ; return (gbl_env { tcg_type_env = type_env2 }) }}}} spliceInHsBootErr (SpliceDecl (L loc _), _) = addErrAt loc (ptext SLIT("Splices are not allowed in hs-boot files")) \end{code} Once we've typechecked the body of the module, we want to compare what we've found (gathered in a TypeEnv) with the hi-boot details (if any). \begin{code} checkHiBootIface :: TcGblEnv -> ModDetails -> TcM TcGblEnv -- Compare the hi-boot file for this module (if there is one) -- with the type environment we've just come up with -- In the common case where there is no hi-boot file, the list -- of boot_names is empty. -- -- The bindings we return give bindings for the dfuns defined in the -- hs-boot file, such as $fbEqT = $fEqT checkHiBootIface tcg_env@(TcGblEnv { tcg_src = hs_src, tcg_binds = binds, tcg_insts = local_insts, tcg_fam_insts = local_fam_insts, tcg_type_env = local_type_env, tcg_exports = local_exports }) (ModDetails { md_insts = boot_insts, md_fam_insts = boot_fam_insts, md_types = boot_type_env, md_exports = boot_exports }) | isHsBoot hs_src -- Current module is already a hs-boot file! = return tcg_env | otherwise = do { traceTc (text "checkHiBootIface" <+> (ppr boot_type_env $$ ppr boot_insts $$ ppr boot_exports)) ; -- Check the exports of the boot module, one by one ; mapM_ check_export boot_exports -- Check instance declarations ; mb_dfun_prs <- mapM check_inst boot_insts ; let tcg_env' = tcg_env { tcg_binds = binds `unionBags` dfun_binds, tcg_type_env = extendTypeEnvWithIds local_type_env boot_dfuns } dfun_prs = catMaybes mb_dfun_prs boot_dfuns = map fst dfun_prs dfun_binds = listToBag [ noLoc $ VarBind boot_dfun (nlHsVar dfun) | (boot_dfun, dfun) <- dfun_prs ] -- Check for no family instances ; unless (null boot_fam_insts) $ panic ("TcRnDriver.checkHiBootIface: Cannot handle family " ++ "instances in boot files yet...") -- FIXME: Why? The actual comparison is not hard, but what would -- be the equivalent to the dfun bindings returned for class -- instances? We can't easily equate tycons... ; return tcg_env' } where check_export boot_avail -- boot_avail is exported by the boot iface | name `elem` dfun_names = return () | isWiredInName name = return () -- No checking for wired-in names. In particular, -- 'error' is handled by a rather gross hack -- (see comments in GHC.Err.hs-boot) -- Check that the actual module exports the same thing | not (null missing_names) = addErrTc (missingBootThing (head missing_names) "exported by") -- If the boot module does not *define* the thing, we are done -- (it simply re-exports it, and names match, so nothing further to do) | isNothing mb_boot_thing = return () -- Check that the actual module also defines the thing, and -- then compare the definitions | Just real_thing <- lookupTypeEnv local_type_env name = do { let boot_decl = tyThingToIfaceDecl (fromJust mb_boot_thing) real_decl = tyThingToIfaceDecl real_thing ; checkTc (checkBootDecl boot_decl real_decl) (bootMisMatch real_thing boot_decl real_decl) } -- The easiest way to check compatibility is to convert to -- iface syntax, where we already have good comparison functions | otherwise = addErrTc (missingBootThing name "defined in") where name = availName boot_avail mb_boot_thing = lookupTypeEnv boot_type_env name missing_names = case lookupNameEnv local_export_env name of Nothing -> [name] Just avail -> availNames boot_avail `minusList` availNames avail dfun_names = map getName boot_insts local_export_env :: NameEnv AvailInfo local_export_env = availsToNameEnv local_exports check_inst :: Instance -> TcM (Maybe (Id, Id)) -- Returns a pair of the boot dfun in terms of the equivalent real dfun check_inst boot_inst = case [dfun | inst <- local_insts, let dfun = instanceDFunId inst, idType dfun `tcEqType` boot_inst_ty ] of [] -> do { addErrTc (instMisMatch boot_inst); return Nothing } (dfun:_) -> return (Just (local_boot_dfun, dfun)) where boot_dfun = instanceDFunId boot_inst boot_inst_ty = idType boot_dfun local_boot_dfun = Id.mkExportedLocalId (idName boot_dfun) boot_inst_ty ---------------- missingBootThing thing what = ppr thing <+> ptext SLIT("is exported by the hs-boot file, but not") <+> text what <+> ptext SLIT("the module") bootMisMatch thing boot_decl real_decl = vcat [ppr thing <+> ptext SLIT("has conflicting definitions in the module and its hs-boot file"), ptext SLIT("Main module:") <+> ppr real_decl, ptext SLIT("Boot file: ") <+> ppr boot_decl] instMisMatch inst = hang (ppr inst) 2 (ptext SLIT("is defined in the hs-boot file, but not in the module itself")) \end{code} %************************************************************************ %* * Type-checking the top level of a module %* * %************************************************************************ tcRnGroup takes a bunch of top-level source-code declarations, and * renames them * gets supporting declarations from interface files * typechecks them * zonks them * and augments the TcGblEnv with the results In Template Haskell it may be called repeatedly for each group of declarations. It expects there to be an incoming TcGblEnv in the monad; it augments it and returns the new TcGblEnv. \begin{code} ------------------------------------------------ rnTopSrcDecls :: HsGroup RdrName -> TcM (TcGblEnv, HsGroup Name) rnTopSrcDecls group = do { -- Bring top level binders into scope tcg_env <- importsFromLocalDecls group ; setGblEnv tcg_env $ do { failIfErrsM ; -- No point in continuing if (say) we have duplicate declarations -- Rename the source decls (tcg_env, rn_decls) <- rnSrcDecls group ; failIfErrsM ; -- save the renamed syntax, if we want it let { tcg_env' | Just grp <- tcg_rn_decls tcg_env = tcg_env{ tcg_rn_decls = Just (appendGroups grp rn_decls) } | otherwise = tcg_env }; -- Dump trace of renaming part rnDump (ppr rn_decls) ; return (tcg_env', rn_decls) }} ------------------------------------------------ tcTopSrcDecls :: ModDetails -> HsGroup Name -> TcM (TcGblEnv, TcLclEnv) tcTopSrcDecls boot_details (HsGroup { hs_tyclds = tycl_decls, hs_instds = inst_decls, hs_derivds = deriv_decls, hs_fords = foreign_decls, hs_defds = default_decls, hs_ruleds = rule_decls, hs_valds = val_binds }) = do { -- Type-check the type and class decls, and all imported decls -- The latter come in via tycl_decls traceTc (text "Tc2") ; tcg_env <- checkNoErrs (tcTyAndClassDecls boot_details tycl_decls) ; -- tcTyAndClassDecls recovers internally, but if anything gave rise to -- an error we'd better stop now, to avoid a cascade -- Make these type and class decls available to stuff slurped from interface files writeMutVar (tcg_type_env_var tcg_env) (tcg_type_env tcg_env) ; setGblEnv tcg_env $ do { -- Source-language instances, including derivings, -- and import the supporting declarations traceTc (text "Tc3") ; (tcg_env, inst_infos, deriv_binds) <- tcInstDecls1 tycl_decls inst_decls deriv_decls; setGblEnv tcg_env $ do { -- Foreign import declarations next. No zonking necessary -- here; we can tuck them straight into the global environment. traceTc (text "Tc4") ; (fi_ids, fi_decls) <- tcForeignImports foreign_decls ; tcExtendGlobalValEnv fi_ids $ do { -- Default declarations traceTc (text "Tc4a") ; default_tys <- tcDefaults default_decls ; updGblEnv (\gbl -> gbl { tcg_default = default_tys }) $ do { -- Value declarations next -- We also typecheck any extra binds that came out -- of the "deriving" process (deriv_binds) traceTc (text "Tc5") ; (tc_val_binds, tcl_env) <- tcTopBinds (val_binds `plusHsValBinds` deriv_binds) ; setLclTypeEnv tcl_env $ do { -- Second pass over class and instance declarations, traceTc (text "Tc6") ; (inst_binds, tcl_env) <- tcInstDecls2 tycl_decls inst_infos ; showLIE (text "after instDecls2") ; -- Foreign exports -- They need to be zonked, so we return them traceTc (text "Tc7") ; (foe_binds, foe_decls) <- tcForeignExports foreign_decls ; -- Rules rules <- tcRules rule_decls ; -- Wrap up traceTc (text "Tc7a") ; tcg_env <- getGblEnv ; let { all_binds = tc_val_binds `unionBags` inst_binds `unionBags` foe_binds ; -- Extend the GblEnv with the (as yet un-zonked) -- bindings, rules, foreign decls tcg_env' = tcg_env { tcg_binds = tcg_binds tcg_env `unionBags` all_binds, tcg_rules = tcg_rules tcg_env ++ rules, tcg_fords = tcg_fords tcg_env ++ foe_decls ++ fi_decls } } ; return (tcg_env', tcl_env) }}}}}} \end{code} %************************************************************************ %* * Checking for 'main' %* * %************************************************************************ \begin{code} checkMain :: TcM TcGblEnv -- If we are in module Main, check that 'main' is defined. checkMain = do { ghc_mode <- getGhcMode ; tcg_env <- getGblEnv ; dflags <- getDOpts ; let { main_mod = mainModIs dflags ; main_fn = case mainFunIs dflags of { Just fn -> mkRdrUnqual (mkVarOccFS (mkFastString fn)) ; Nothing -> main_RDR_Unqual } } ; check_main ghc_mode tcg_env main_mod main_fn } check_main ghc_mode tcg_env main_mod main_fn | mod /= main_mod = traceTc (text "checkMain not" <+> ppr main_mod <+> ppr mod) >> return tcg_env | otherwise = addErrCtxt mainCtxt $ do { mb_main <- lookupSrcOcc_maybe main_fn -- Check that 'main' is in scope -- It might be imported from another module! ; case mb_main of { Nothing -> do { traceTc (text "checkMain fail" <+> ppr main_mod <+> ppr main_fn) ; complain_no_main ; return tcg_env } ; Just main_name -> do { traceTc (text "checkMain found" <+> ppr main_mod <+> ppr main_fn) ; dflags <- getDOpts ; case hscTarget dflags of { -- We do main as a normal foreign export in java HscJava -> do { uniq <- newUnique ; let { a = mkSystemVarName uniq FSLIT("a") ; rhs = nlHsLam (mkSimpleHsAlt (nlVarPat a) (nlHsApps runMainIOName [nlHsApps withArgvName [nlHsLit (HsStringPrim (moduleNameFS (moduleName main_mod))) ,nlHsVar a ,nlHsApps thenIOName [nlHsVar main_name ,nlHsApps returnIOName [nlHsVar (idName unitDataConId)] ]]])) } -- main$f :: UArray# String# -> IO () -- main$f = \a -> runMainIO (withArgv# "me" a main) ; (main_expr, ty) <- setSrcSpan (srcLocSpan (getSrcLoc main_name)) $ tcInferRho rhs ; uniq <- newUnique ; let { export_main_name = mkInternalName uniq (mkVarOccFS FSLIT("main$f")) (getSrcLoc main_name) ; export_main_id = Id.mkLocalId export_main_name ty ; main_bind = noLoc (VarBind export_main_id main_expr) ; main_export = ForeignExport (noLoc export_main_id) undefined (JVMExport FSLIT("main")) ; main_lexport = L (srcLocSpan (getSrcLoc main_name)) main_export } ; return (tcg_env { tcg_binds = tcg_binds tcg_env `snocBag` main_bind , tcg_fords = main_lexport : tcg_fords tcg_env }) }; _ -> do { ; let { rhs = nlHsApp (nlHsVar runMainIOName) (nlHsVar main_name) } -- :Main.main :: IO () = runMainIO main ; (main_expr, ty) <- setSrcSpan (srcLocSpan (getSrcLoc main_name)) $ tcInferRho rhs -- See Note [Root-main Id] ; let { root_main_name = mkExternalName rootMainKey rOOT_MAIN (mkVarOccFS FSLIT("main")) (getSrcLoc main_name) ; root_main_id = Id.mkExportedLocalId root_main_name ty ; main_bind = noLoc (VarBind root_main_id main_expr) } ; return (tcg_env { tcg_binds = tcg_binds tcg_env `snocBag` main_bind, tcg_dus = tcg_dus tcg_env `plusDU` usesOnly (unitFV main_name) -- Record the use of 'main', so that we don't -- complain about it being defined but not used }) }}}}} where mod = tcg_mod tcg_env complain_no_main | ghc_mode == Interactive = return () | otherwise = failWithTc noMainMsg -- In interactive mode, don't worry about the absence of 'main' -- In other modes, fail altogether, so that we don't go on -- and complain a second time when processing the export list. mainCtxt = ptext SLIT("When checking the type of the main function") <+> quotes (ppr main_fn) noMainMsg = ptext SLIT("The main function") <+> quotes (ppr main_fn) <+> ptext SLIT("is not defined in module") <+> quotes (ppr main_mod) \end{code} Note [Root-main Id] ~~~~~~~~~~~~~~~~~~~ The function that the RTS invokes is always :Main.main, which we call root_main_id. (Because GHC allows the user to have a module not called Main as the main module, we can't rely on the main function being called "Main.main". That's why root_main_id has a fixed module ":Main".) This is unusual: it's a LocalId whose Name has a Module from another module. Tiresomely, we must filter it out again in MkIface, les we get two defns for 'main' in the interface file! %********************************************************* %* * GHCi stuff %* * %********************************************************* \begin{code} #ifdef GHCI setInteractiveContext :: HscEnv -> InteractiveContext -> TcRn a -> TcRn a setInteractiveContext hsc_env icxt thing_inside = let -- Initialise the tcg_inst_env with instances -- from all home modules. This mimics the more selective -- call to hptInstances in tcRnModule dfuns = hptInstances hsc_env (\mod -> True) in updGblEnv (\env -> env { tcg_rdr_env = ic_rn_gbl_env icxt, tcg_type_env = ic_type_env icxt, tcg_inst_env = extendInstEnvList (tcg_inst_env env) dfuns }) $ updLclEnv (\env -> env { tcl_rdr = ic_rn_local_env icxt }) $ do { traceTc (text "setIC" <+> ppr (ic_type_env icxt)) ; thing_inside } \end{code} \begin{code} tcRnStmt :: HscEnv -> InteractiveContext -> LStmt RdrName -> IO (Maybe (InteractiveContext, [Name], LHsExpr Id)) -- The returned [Name] is the same as the input except for -- ExprStmt, in which case the returned [Name] is [itName] -- -- The returned TypecheckedHsExpr is of type IO [ () ], -- a list of the bound values, coerced to (). tcRnStmt hsc_env ictxt rdr_stmt = initTcPrintErrors hsc_env iNTERACTIVE $ setInteractiveContext hsc_env ictxt $ do { -- Rename; use CmdLineMode because tcRnStmt is only used interactively (([rn_stmt], _), fvs) <- rnStmts DoExpr [rdr_stmt] (return ((), emptyFVs)) ; traceRn (text "tcRnStmt" <+> vcat [ppr rdr_stmt, ppr rn_stmt, ppr fvs]) ; failIfErrsM ; -- The real work is done here (bound_ids, tc_expr) <- mkPlan rn_stmt ; zonked_expr <- zonkTopLExpr tc_expr ; zonked_ids <- zonkTopBndrs bound_ids ; -- None of the Ids should be of unboxed type, because we -- cast them all to HValues in the end! mappM bad_unboxed (filter (isUnLiftedType . idType) zonked_ids) ; traceTc (text "tcs 1") ; let { -- (a) Make all the bound ids "global" ids, now that -- they're notionally top-level bindings. This is -- important: otherwise when we come to compile an expression -- using these ids later, the byte code generator will consider -- the occurrences to be free rather than global. -- -- (b) Tidy their types; this is important, because :info may -- ask to look at them, and :info expects the things it looks -- up to have tidy types global_ids = map globaliseAndTidy zonked_ids ; -- Update the interactive context rn_env = ic_rn_local_env ictxt ; type_env = ic_type_env ictxt ; bound_names = map idName global_ids ; new_rn_env = extendLocalRdrEnv rn_env bound_names ; {- --------------------------------------------- At one stage I removed any shadowed bindings from the type_env; they are inaccessible but might, I suppose, cause a space leak if we leave them there. However, with Template Haskell they aren't necessarily inaccessible. Consider this GHCi session Prelude> let f n = n * 2 :: Int Prelude> fName <- runQ [| f |] Prelude> $(return $ AppE fName (LitE (IntegerL 7))) 14 Prelude> let f n = n * 3 :: Int Prelude> $(return $ AppE fName (LitE (IntegerL 7))) In the last line we use 'fName', which resolves to the *first* 'f' in scope. If we delete it from the type env, GHCi crashes because it doesn't expect that. Hence this code is commented out shadowed = [ n | name <- bound_names, let rdr_name = mkRdrUnqual (nameOccName name), Just n <- [lookupLocalRdrEnv rn_env rdr_name] ] ; filtered_type_env = delListFromNameEnv type_env shadowed ; -------------------------------------------------- -} new_type_env = extendTypeEnvWithIds type_env global_ids ; new_ic = ictxt { ic_rn_local_env = new_rn_env, ic_type_env = new_type_env } } ; dumpOptTcRn Opt_D_dump_tc (vcat [text "Bound Ids" <+> pprWithCommas ppr global_ids, text "Typechecked expr" <+> ppr zonked_expr]) ; returnM (new_ic, bound_names, zonked_expr) } where bad_unboxed id = addErr (sep [ptext SLIT("GHCi can't bind a variable of unlifted type:"), nest 2 (ppr id <+> dcolon <+> ppr (idType id))]) globaliseAndTidy :: Id -> Id globaliseAndTidy id -- Give the Id a Global Name, and tidy its type = Id.setIdType (globaliseId VanillaGlobal id) tidy_type where tidy_type = tidyTopType (idType id) \end{code} Here is the grand plan, implemented in tcUserStmt What you type The IO [HValue] that hscStmt returns ------------- ------------------------------------ let pat = expr ==> let pat = expr in return [coerce HVal x, coerce HVal y, ...] bindings: [x,y,...] pat <- expr ==> expr >>= \ pat -> return [coerce HVal x, coerce HVal y, ...] bindings: [x,y,...] expr (of IO type) ==> expr >>= \ it -> return [coerce HVal it] [NB: result not printed] bindings: [it] expr (of non-IO type, ==> let it = expr in print it >> return [coerce HVal it] result showable) bindings: [it] expr (of non-IO type, result not showable) ==> error \begin{code} --------------------------- type PlanResult = ([Id], LHsExpr Id) type Plan = TcM PlanResult runPlans :: [Plan] -> TcM PlanResult -- Try the plans in order. If one fails (by raising an exn), try the next. -- If one succeeds, take it. runPlans [] = panic "runPlans" runPlans [p] = p runPlans (p:ps) = tryTcLIE_ (runPlans ps) p -------------------- mkPlan :: LStmt Name -> TcM PlanResult mkPlan (L loc (ExprStmt expr _ _)) -- An expression typed at the prompt = do { uniq <- newUnique -- is treated very specially ; let fresh_it = itName uniq the_bind = L loc $ mkFunBind (L loc fresh_it) matches matches = [mkMatch [] expr emptyLocalBinds] let_stmt = L loc $ LetStmt (HsValBinds (ValBindsOut [(NonRecursive,unitBag the_bind)] [])) bind_stmt = L loc $ BindStmt (nlVarPat fresh_it) expr (HsVar bindIOName) noSyntaxExpr print_it = L loc $ ExprStmt (nlHsApp (nlHsVar printName) (nlHsVar fresh_it)) (HsVar thenIOName) placeHolderType -- The plans are: -- [it <- e; print it] but not if it::() -- [it <- e] -- [let it = e; print it] ; runPlans [ -- Plan A do { stuff@([it_id], _) <- tcGhciStmts [bind_stmt, print_it] ; it_ty <- zonkTcType (idType it_id) ; ifM (isUnitTy it_ty) failM ; return stuff }, -- Plan B; a naked bind statment tcGhciStmts [bind_stmt], -- Plan C; check that the let-binding is typeable all by itself. -- If not, fail; if so, try to print it. -- The two-step process avoids getting two errors: one from -- the expression itself, and one from the 'print it' part -- This two-step story is very clunky, alas do { checkNoErrs (tcGhciStmts [let_stmt]) --- checkNoErrs defeats the error recovery of let-bindings ; tcGhciStmts [let_stmt, print_it] } ]} mkPlan stmt@(L loc (BindStmt {})) | [L _ v] <- collectLStmtBinders stmt -- One binder, for a bind stmt = do { let print_v = L loc $ ExprStmt (nlHsApp (nlHsVar printName) (nlHsVar v)) (HsVar thenIOName) placeHolderType ; print_bind_result <- doptM Opt_PrintBindResult ; let print_plan = do { stuff@([v_id], _) <- tcGhciStmts [stmt, print_v] ; v_ty <- zonkTcType (idType v_id) ; ifM (isUnitTy v_ty || not (isTauTy v_ty)) failM ; return stuff } -- The plans are: -- [stmt; print v] but not if v::() -- [stmt] ; runPlans ((if print_bind_result then [print_plan] else []) ++ [tcGhciStmts [stmt]]) } mkPlan stmt = tcGhciStmts [stmt] --------------------------- tcGhciStmts :: [LStmt Name] -> TcM PlanResult tcGhciStmts stmts = do { ioTyCon <- tcLookupTyCon ioTyConName ; ret_id <- tcLookupId returnIOName ; -- return @ IO let { io_ty = mkTyConApp ioTyCon [] ; ret_ty = mkListTy unitTy ; io_ret_ty = mkTyConApp ioTyCon [ret_ty] ; tc_io_stmts stmts = tcStmts DoExpr (tcDoStmt io_ty) stmts (emptyRefinement, io_ret_ty) ; names = map unLoc (collectLStmtsBinders stmts) ; -- mk_return builds the expression -- returnIO @ [()] [coerce () x, .., coerce () z] -- -- Despite the inconvenience of building the type applications etc, -- this *has* to be done in type-annotated post-typecheck form -- because we are going to return a list of *polymorphic* values -- coerced to type (). If we built a *source* stmt -- return [coerce x, ..., coerce z] -- then the type checker would instantiate x..z, and we wouldn't -- get their *polymorphic* values. (And we'd get ambiguity errs -- if they were overloaded, since they aren't applied to anything.) mk_return ids = nlHsApp (nlHsTyApp ret_id [ret_ty]) (noLoc $ ExplicitList unitTy (map mk_item ids)) ; mk_item id = nlHsApp (nlHsTyApp unsafeCoerceId [idType id, unitTy]) (nlHsVar id) } ; -- OK, we're ready to typecheck the stmts traceTc (text "tcs 2") ; ((tc_stmts, ids), lie) <- getLIE $ tc_io_stmts stmts $ \ _ -> mappM tcLookupId names ; -- Look up the names right in the middle, -- where they will all be in scope -- Simplify the context const_binds <- checkNoErrs (tcSimplifyInteractive lie) ; -- checkNoErrs ensures that the plan fails if context redn fails return (ids, mkHsDictLet const_binds $ noLoc (HsDo DoExpr tc_stmts (mk_return ids) io_ret_ty)) } \end{code} tcRnExpr just finds the type of an expression \begin{code} tcRnExpr :: HscEnv -> InteractiveContext -> LHsExpr RdrName -> IO (Maybe Type) tcRnExpr hsc_env ictxt rdr_expr = initTcPrintErrors hsc_env iNTERACTIVE $ setInteractiveContext hsc_env ictxt $ do { (rn_expr, fvs) <- rnLExpr rdr_expr ; failIfErrsM ; -- Now typecheck the expression; -- it might have a rank-2 type (e.g. :t runST) ((tc_expr, res_ty), lie) <- getLIE (tcInferRho rn_expr) ; ((qtvs, dict_insts, _), lie_top) <- getLIE (tcSimplifyInfer smpl_doc (tyVarsOfType res_ty) lie) ; tcSimplifyInteractive lie_top ; let { all_expr_ty = mkForAllTys qtvs $ mkFunTys (map (idType . instToId) dict_insts) $ res_ty } ; zonkTcType all_expr_ty } where smpl_doc = ptext SLIT("main expression") \end{code} tcRnType just finds the kind of a type \begin{code} tcRnType :: HscEnv -> InteractiveContext -> LHsType RdrName -> IO (Maybe Kind) tcRnType hsc_env ictxt rdr_type = initTcPrintErrors hsc_env iNTERACTIVE $ setInteractiveContext hsc_env ictxt $ do { rn_type <- rnLHsType doc rdr_type ; failIfErrsM ; -- Now kind-check the type (ty', kind) <- kcHsType rn_type ; return kind } where doc = ptext SLIT("In GHCi input") #endif /* GHCi */ \end{code} %************************************************************************ %* * More GHCi stuff, to do with browsing and getting info %* * %************************************************************************ \begin{code} #ifdef GHCI -- ASSUMES that the module is either in the HomePackageTable or is -- a package module with an interface on disk. If neither of these is -- true, then the result will be an error indicating the interface -- could not be found. getModuleExports :: HscEnv -> Module -> IO (Messages, Maybe [AvailInfo]) getModuleExports hsc_env mod = let ic = hsc_IC hsc_env checkMods = ic_toplev_scope ic ++ ic_exports ic in initTc hsc_env HsSrcFile False iNTERACTIVE (tcGetModuleExports mod checkMods) -- Get the export avail info and also load all orphan and family-instance -- modules. Finally, check that the family instances of all modules in the -- interactive context are consistent (these modules are in the second -- argument). tcGetModuleExports :: Module -> [Module] -> TcM [AvailInfo] tcGetModuleExports mod directlyImpMods = do { let doc = ptext SLIT("context for compiling statements") ; iface <- initIfaceTcRn $ loadSysInterface doc mod -- Load any orphan-module and family instance-module -- interfaces, so their instances are visible. ; loadOrphanModules (dep_orphs (mi_deps iface)) False ; loadOrphanModules (dep_finsts (mi_deps iface)) True -- Check that the family instances of all directly loaded -- modules are consistent. ; checkFamInstConsistency (dep_finsts (mi_deps iface)) directlyImpMods ; ifaceExportNames (mi_exports iface) } tcRnLookupRdrName :: HscEnv -> RdrName -> IO (Maybe [Name]) tcRnLookupRdrName hsc_env rdr_name = initTcPrintErrors hsc_env iNTERACTIVE $ setInteractiveContext hsc_env (hsc_IC hsc_env) $ lookup_rdr_name rdr_name lookup_rdr_name rdr_name = do { -- If the identifier is a constructor (begins with an -- upper-case letter), then we need to consider both -- constructor and type class identifiers. let { rdr_names = dataTcOccs rdr_name } ; -- results :: [Either Messages Name] results <- mapM (tryTcErrs . lookupOccRn) rdr_names ; traceRn (text "xx" <+> vcat [ppr rdr_names, ppr (map snd results)]); -- The successful lookups will be (Just name) let { (warns_s, good_names) = unzip [ (msgs, name) | (msgs, Just name) <- results] ; errs_s = [msgs | (msgs, Nothing) <- results] } ; -- Fail if nothing good happened, else add warnings if null good_names then -- No lookup succeeded, so -- pick the first error message and report it -- ToDo: If one of the errors is "could be Foo.X or Baz.X", -- while the other is "X is not in scope", -- we definitely want the former; but we might pick the latter do { addMessages (head errs_s) ; failM } else -- Add deprecation warnings mapM_ addMessages warns_s ; return good_names } tcRnRecoverDataCon :: HscEnv -> a -> IO (Maybe DataCon) tcRnRecoverDataCon hsc_env a = initTcPrintErrors hsc_env iNTERACTIVE $ setInteractiveContext hsc_env (hsc_IC hsc_env) $ do name <- recoverDataCon a tcLookupDataCon name tcRnLookupName :: HscEnv -> Name -> IO (Maybe TyThing) tcRnLookupName hsc_env name = initTcPrintErrors hsc_env iNTERACTIVE $ setInteractiveContext hsc_env (hsc_IC hsc_env) $ tcLookupGlobal name tcRnGetInfo :: HscEnv -> Name -> IO (Maybe (TyThing, Fixity, [Instance])) -- Used to implemnent :info in GHCi -- -- Look up a RdrName and return all the TyThings it might be -- A capitalised RdrName is given to us in the DataName namespace, -- but we want to treat it as *both* a data constructor -- *and* as a type or class constructor; -- hence the call to dataTcOccs, and we return up to two results tcRnGetInfo hsc_env name = initTcPrintErrors hsc_env iNTERACTIVE $ let ictxt = hsc_IC hsc_env in setInteractiveContext hsc_env ictxt $ do -- Load the interface for all unqualified types and classes -- That way we will find all the instance declarations -- (Packages have not orphan modules, and we assume that -- in the home package all relevant modules are loaded.) loadUnqualIfaces ictxt thing <- tcLookupGlobal name fixity <- lookupFixityRn name ispecs <- lookupInsts (icPrintUnqual ictxt) thing return (thing, fixity, ispecs) lookupInsts :: PrintUnqualified -> TyThing -> TcM [Instance] -- Filter the instances by the ones whose tycons (or clases resp) -- are in scope unqualified. Otherwise we list a whole lot too many! lookupInsts print_unqual (AClass cls) = do { inst_envs <- tcGetInstEnvs ; return [ ispec | ispec <- classInstances inst_envs cls , plausibleDFun print_unqual (instanceDFunId ispec) ] } lookupInsts print_unqual (ATyCon tc) = do { eps <- getEps -- Load all instances for all classes that are -- in the type environment (which are all the ones -- we've seen in any interface file so far) ; (pkg_ie, home_ie) <- tcGetInstEnvs -- Search all ; return [ ispec | ispec <- instEnvElts home_ie ++ instEnvElts pkg_ie , let dfun = instanceDFunId ispec , relevant dfun , plausibleDFun print_unqual dfun ] } where relevant df = tc_name `elemNameSet` tyClsNamesOfDFunHead (idType df) tc_name = tyConName tc lookupInsts print_unqual other = return [] plausibleDFun print_unqual dfun -- Dfun involving only names that print unqualified = all ok (nameSetToList (tyClsNamesOfType (idType dfun))) where ok name | isBuiltInSyntax name = True | isExternalName name = isNothing $ fst print_unqual (nameModule name) (nameOccName name) | otherwise = True loadUnqualIfaces :: InteractiveContext -> TcM () -- Load the home module for everything that is in scope unqualified -- This is so that we can accurately report the instances for -- something loadUnqualIfaces ictxt = initIfaceTcRn $ mapM_ (loadSysInterface doc) (moduleSetElts (mkModuleSet unqual_mods)) where unqual_mods = [ nameModule name | gre <- globalRdrEnvElts (ic_rn_gbl_env ictxt), let name = gre_name gre, not (isInternalName name), isTcOcc (nameOccName name), -- Types and classes only unQualOK gre ] -- In scope unqualified doc = ptext SLIT("Need interface for module whose export(s) are in scope unqualified") #endif /* GHCI */ \end{code} %************************************************************************ %* * Degugging output %* * %************************************************************************ \begin{code} rnDump :: SDoc -> TcRn () -- Dump, with a banner, if -ddump-rn rnDump doc = do { dumpOptTcRn Opt_D_dump_rn (mkDumpDoc "Renamer" doc) } tcDump :: TcGblEnv -> TcRn () tcDump env = do { dflags <- getDOpts ; -- Dump short output if -ddump-types or -ddump-tc ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags) (dumpTcRn short_dump) ; -- Dump bindings if -ddump-tc dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump) } where short_dump = pprTcGblEnv env full_dump = pprLHsBinds (tcg_binds env) -- NB: foreign x-d's have undefined's in their types; -- hence can't show the tc_fords tcCoreDump mod_guts = do { dflags <- getDOpts ; ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags) (dumpTcRn (pprModGuts mod_guts)) ; -- Dump bindings if -ddump-tc dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump) } where full_dump = pprCoreBindings (mg_binds mod_guts) -- It's unpleasant having both pprModGuts and pprModDetails here pprTcGblEnv :: TcGblEnv -> SDoc pprTcGblEnv (TcGblEnv { tcg_type_env = type_env, tcg_insts = insts, tcg_fam_insts = fam_insts, tcg_rules = rules, tcg_imports = imports }) = vcat [ ppr_types insts type_env , ppr_tycons fam_insts type_env , ppr_insts insts , ppr_fam_insts fam_insts , vcat (map ppr rules) , ppr_gen_tycons (typeEnvTyCons type_env) , ptext SLIT("Dependent modules:") <+> ppr (eltsUFM (imp_dep_mods imports)) , ptext SLIT("Dependent packages:") <+> ppr (imp_dep_pkgs imports)] pprModGuts :: ModGuts -> SDoc pprModGuts (ModGuts { mg_types = type_env, mg_rules = rules }) = vcat [ ppr_types [] type_env, ppr_rules rules ] ppr_types :: [Instance] -> TypeEnv -> SDoc ppr_types insts type_env = text "TYPE SIGNATURES" $$ nest 4 (ppr_sigs ids) where dfun_ids = map instanceDFunId insts ids = [id | id <- typeEnvIds type_env, want_sig id] want_sig id | opt_PprStyle_Debug = True | otherwise = isLocalId id && isExternalName (idName id) && not (id `elem` dfun_ids) -- isLocalId ignores data constructors, records selectors etc. -- The isExternalName ignores local dictionary and method bindings -- that the type checker has invented. Top-level user-defined things -- have External names. ppr_tycons :: [FamInst] -> TypeEnv -> SDoc ppr_tycons fam_insts type_env = text "TYPE CONSTRUCTORS" $$ nest 4 (ppr_tydecls tycons) where fi_tycons = map famInstTyCon fam_insts tycons = [tycon | tycon <- typeEnvTyCons type_env, want_tycon tycon] want_tycon tycon | opt_PprStyle_Debug = True | otherwise = not (isImplicitTyCon tycon) && isExternalName (tyConName tycon) && not (tycon `elem` fi_tycons) ppr_insts :: [Instance] -> SDoc ppr_insts [] = empty ppr_insts ispecs = text "INSTANCES" $$ nest 2 (pprInstances ispecs) ppr_fam_insts :: [FamInst] -> SDoc ppr_fam_insts [] = empty ppr_fam_insts fam_insts = text "FAMILY INSTANCES" $$ nest 2 (pprFamInsts fam_insts) ppr_sigs :: [Var] -> SDoc ppr_sigs ids -- Print type signatures; sort by OccName = vcat (map ppr_sig (sortLe le_sig ids)) where le_sig id1 id2 = getOccName id1 <= getOccName id2 ppr_sig id = ppr id <+> dcolon <+> ppr (tidyTopType (idType id)) ppr_tydecls :: [TyCon] -> SDoc ppr_tydecls tycons -- Print type constructor info; sort by OccName = vcat (map ppr_tycon (sortLe le_sig tycons)) where le_sig tycon1 tycon2 = getOccName tycon1 <= getOccName tycon2 ppr_tycon tycon | isCoercionTyCon tycon = ptext SLIT("coercion") <+> ppr tycon | otherwise = ppr (tyThingToIfaceDecl (ATyCon tycon)) ppr_rules :: [CoreRule] -> SDoc ppr_rules [] = empty ppr_rules rs = vcat [ptext SLIT("{-# RULES"), nest 4 (pprRules rs), ptext SLIT("#-}")] ppr_gen_tycons [] = empty ppr_gen_tycons tcs = vcat [ptext SLIT("Tycons with generics:"), nest 2 (fsep (map ppr (filter tyConHasGenerics tcs)))] \end{code}