%
-% (c) The GRASP/AQUA Project, Glasgow University, 1992-1996
+% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
%
\section[TcModule]{Typechecking a whole module}
\begin{code}
-#include "HsVersions.h"
-
module TcModule (
typecheckModule,
- SYN_IE(TcResults),
- SYN_IE(TcSpecialiseRequests),
- SYN_IE(TcDDumpDeriv)
+ TcResults(..)
) where
-IMP_Ubiq(){-uitous-}
+#include "HsVersions.h"
-import CmdLineOpts ( opt_D_dump_tc, opt_D_dump_deriv )
-import HsSyn ( HsDecl(..), HsModule(..), HsBinds(..), HsExpr, MonoBinds(..),
- TyDecl, SpecDataSig, ClassDecl, InstDecl, IfaceSig,
- SpecInstSig, DefaultDecl, Sig, Fake, InPat,
- SYN_IE(RecFlag), nonRecursive, GRHSsAndBinds, Match,
- FixityDecl, IE, ImportDecl, OutPat
+import CmdLineOpts ( DynFlag(..), DynFlags, opt_PprStyle_Debug )
+import HsSyn ( HsBinds(..), MonoBinds(..), HsDecl(..) )
+import HsTypes ( toHsType )
+import RnHsSyn ( RenamedHsDecl )
+import TcHsSyn ( TypecheckedMonoBinds,
+ TypecheckedForeignDecl, TypecheckedRuleDecl,
+ zonkTopBinds, zonkForeignExports, zonkRules
)
-import RnHsSyn ( SYN_IE(RenamedHsModule), RenamedFixityDecl(..) )
-import TcHsSyn ( SYN_IE(TypecheckedHsBinds), SYN_IE(TypecheckedHsExpr),
- SYN_IE(TypecheckedDictBinds), SYN_IE(TcMonoBinds),
- SYN_IE(TypecheckedMonoBinds),
- zonkTopBinds )
import TcMonad
-import Inst ( Inst, emptyLIE, plusLIE )
-import TcBinds ( tcBindsAndThen )
-import TcClassDcl ( tcClassDecls2 )
+import Inst ( plusLIE )
+import TcBinds ( tcTopBinds )
+import TcClassDcl ( tcClassDecls2, mkImplicitClassBinds )
import TcDefaults ( tcDefaults )
-import TcEnv ( tcExtendGlobalValEnv, getEnv_LocalIds,
- getEnv_TyCons, getEnv_Classes, tcLookupLocalValue,
- tcLookupLocalValueByKey, tcLookupTyCon,
- tcLookupGlobalValueByKeyMaybe )
-import SpecEnv ( SpecEnv )
-import TcExpr ( tcId )
+import TcEnv ( TcEnv, tcExtendGlobalValEnv, tcLookupGlobal_maybe,
+ tcEnvTyCons, tcEnvClasses,
+ tcSetEnv, tcSetInstEnv, initTcEnv, getTcGEnv
+ )
+import TcRules ( tcRules )
+import TcForeign ( tcForeignImports, tcForeignExports )
import TcIfaceSig ( tcInterfaceSigs )
import TcInstDcls ( tcInstDecls1, tcInstDecls2 )
-import TcInstUtil ( buildInstanceEnvs, InstInfo )
+import InstEnv ( InstInfo(..) )
import TcSimplify ( tcSimplifyTop )
-import TcTyClsDecls ( tcTyAndClassDecls1 )
-import TcTyDecls ( mkDataBinds )
-import TcType ( TcIdOcc(..), SYN_IE(TcType), tcInstType )
-import TcKind ( TcKind )
-
-import RnMonad ( RnNameSupply(..) )
-import Bag ( listToBag )
-import ErrUtils ( SYN_IE(Warning), SYN_IE(Error),
- pprBagOfErrors, dumpIfSet, ghcExit
+import TcTyClsDecls ( tcTyAndClassDecls )
+import TcTyDecls ( mkImplicitDataBinds )
+
+import CoreUnfold ( unfoldingTemplate )
+import Type ( funResultTy, splitForAllTys )
+import Bag ( isEmptyBag )
+import ErrUtils ( printErrorsAndWarnings, dumpIfSet_dyn )
+import Id ( idType, idName, idUnfolding )
+import Module ( Module, moduleName, plusModuleEnv )
+import Name ( Name, nameOccName, isLocallyDefined, isGlobalName,
+ toRdrName, nameEnvElts, emptyNameEnv, lookupNameEnv
)
-import Id ( idType, GenId, SYN_IE(IdEnv), nullIdEnv )
-import Maybes ( catMaybes, MaybeErr(..) )
-import Name ( Name, isLocallyDefined, pprModule )
-import Pretty
-import TyCon ( TyCon, isSynTyCon )
-import Class ( GenClass, SYN_IE(Class), classSelIds )
-import Type ( applyTyCon, mkSynTy, SYN_IE(Type) )
-import PprType ( GenType, GenTyVar )
-import TysWiredIn ( unitTy )
-import PrelMods ( gHC_MAIN, mAIN )
-import PrelInfo ( main_NAME, ioTyCon_NAME )
-import TyVar ( GenTyVar, SYN_IE(TyVarEnv), nullTyVarEnv )
-import Unify ( unifyTauTy )
-import UniqFM ( lookupUFM_Directly, lookupWithDefaultUFM_Directly,
- filterUFM, eltsUFM )
-import Unique ( Unique )
-import UniqSupply ( UniqSupply )
+import TyCon ( tyConGenInfo, isClassTyCon )
+import OccName ( isSysOcc )
+import PrelNames ( mAIN_Name, mainName )
+import Maybes ( thenMaybe )
import Util
-import Bag ( Bag, isEmptyBag )
-
-import FiniteMap ( emptyFM, FiniteMap )
-
-import Outputable ( Outputable(..), PprStyle, printErrs, pprDumpStyle, pprErrorsStyle )
-
-tycon_specs = emptyFM
+import BasicTypes ( EP(..), Fixity )
+import Bag ( isEmptyBag )
+import Outputable
+import HscTypes ( PersistentCompilerState(..), HomeSymbolTable, HomeIfaceTable,
+ PackageSymbolTable, PackageIfaceTable, DFunId, ModIface(..),
+ TypeEnv, extendTypeEnv, lookupTable,
+ TyThing(..), groupTyThings )
+import FiniteMap ( FiniteMap, delFromFM, lookupWithDefaultFM )
\end{code}
Outside-world interface:
\begin{code}
---ToDo: put this in HsVersions
-#if __GLASGOW_HASKELL__ >= 200
-# define REAL_WORLD RealWorld
-#else
-# define REAL_WORLD _RealWorld
-#endif
-
-- Convenient type synonyms first:
-type TcResults
- = (TypecheckedMonoBinds,
- [TyCon], [Class],
- Bag InstInfo, -- Instance declaration information
- TcSpecialiseRequests,
- TcDDumpDeriv)
-
-type TcSpecialiseRequests
- = FiniteMap TyCon [(Bool, [Maybe Type])]
- -- source tycon specialisation requests
-
-type TcDDumpDeriv
- = PprStyle -> Doc
+data TcResults
+ = TcResults {
+ tc_pcs :: PersistentCompilerState, -- Augmented with imported information,
+ -- (but not stuff from this module)
+
+ -- All these fields have info *just for this module*
+ tc_env :: TypeEnv, -- The top level TypeEnv
+ tc_insts :: [DFunId], -- Instances
+ tc_binds :: TypecheckedMonoBinds, -- Bindings
+ tc_fords :: [TypecheckedForeignDecl], -- Foreign import & exports.
+ tc_rules :: [TypecheckedRuleDecl] -- Transformation rules
+ }
---------------
typecheckModule
- :: UniqSupply
- -> RnNameSupply
- -> RenamedHsModule
+ :: DynFlags
+ -> Module
+ -> PersistentCompilerState
+ -> HomeSymbolTable -> HomeIfaceTable
+ -> [RenamedHsDecl]
-> IO (Maybe TcResults)
-typecheckModule us rn_name_supply mod
- = case initTc us (tcModule rn_name_supply mod) of
- Failed (errs, warns) ->
- print_errs warns >>
- print_errs errs >>
- return Nothing
+typecheckModule dflags this_mod pcs hst hit decls
+ = do env <- initTcEnv global_symbol_table
+
+ (maybe_result, (errs,warns)) <- initTc dflags env tc_module
- Succeeded (results@(binds, _, _, _, _, dump_deriv), warns) ->
- print_errs warns >>
+ let { maybe_tc_result :: Maybe TcResults ;
+ maybe_tc_result = case maybe_result of
+ Nothing -> Nothing
+ Just (_,r) -> Just r }
- dumpIfSet opt_D_dump_tc "Typechecked"
- (ppr pprDumpStyle binds) >>
+ printErrorsAndWarnings (errs,warns)
+ printTcDump dflags maybe_tc_result
- dumpIfSet opt_D_dump_deriv "Derived instances"
- (dump_deriv pprDumpStyle) >>
+ if isEmptyBag errs then
+ return Nothing
+ else
+ return maybe_tc_result
+ where
+ global_symbol_table = pcs_PST pcs `plusModuleEnv` hst
- return (Just results)
+ tc_module :: TcM (TcEnv, TcResults)
+ tc_module = fixTc (\ ~(unf_env ,_) -> tcModule pcs hst get_fixity this_mod decls unf_env)
-print_errs errs
- | isEmptyBag errs = return ()
- | otherwise = printErrs (pprBagOfErrors pprErrorsStyle errs)
+ pit = pcs_PIT pcs
+
+ get_fixity :: Name -> Maybe Fixity
+ get_fixity nm = lookupTable hit pit nm `thenMaybe` \ iface ->
+ lookupNameEnv (mi_fixities iface) nm
\end{code}
The internal monster:
\begin{code}
-tcModule :: RnNameSupply -- for renaming derivings
- -> RenamedHsModule -- input
- -> TcM s TcResults -- output
-
-tcModule rn_name_supply
- (HsModule mod_name verion exports imports fixities decls src_loc)
- = tcAddSrcLoc src_loc $ -- record where we're starting
-
- fixTc (\ ~(unf_env ,_) ->
- -- unf_env is used for type-checking interface pragmas
- -- which is done lazily [ie failure just drops the pragma
- -- without having any global-failure effect].
- --
- -- unf_env is also used to get the pragam info for dfuns.
-
- -- The knot for instance information. This isn't used at all
- -- till we type-check value declarations
- fixTc ( \ ~(rec_inst_mapper, _, _, _, _) ->
+tcModule :: PersistentCompilerState
+ -> HomeSymbolTable
+ -> (Name -> Maybe Fixity)
+ -> Module
+ -> [RenamedHsDecl]
+ -> TcEnv -- The knot-tied environment
+ -> TcM (TcEnv, TcResults)
+
+ -- (unf_env :: TcEnv) is used for type-checking interface pragmas
+ -- which is done lazily [ie failure just drops the pragma
+ -- without having any global-failure effect].
+ --
+ -- unf_env is also used to get the pragama info
+ -- for imported dfuns and default methods
+
+tcModule pcs hst get_fixity this_mod decls unf_env
+ = -- Type-check the type and class decls
+ tcTyAndClassDecls unf_env decls `thenTc` \ env ->
+ tcSetEnv env $
+ let
+ classes = tcEnvClasses env
+ tycons = tcEnvTyCons env -- INCLUDES tycons derived from classes
+ local_tycons = [ tc | tc <- tycons,
+ isLocallyDefined tc,
+ not (isClassTyCon tc)
+ ]
+ -- For local_tycons, filter out the ones derived from classes
+ -- Otherwise the latter show up in interface files
+ in
- -- Type-check the type and class decls
- -- trace "tcTyAndClassDecls:" $
- tcTyAndClassDecls1 unf_env rec_inst_mapper decls `thenTc` \ env ->
+ -- Typecheck the instance decls, includes deriving
+ tcInstDecls1 (pcs_insts pcs) (pcs_PRS pcs)
+ hst unf_env get_fixity this_mod
+ local_tycons decls `thenTc` \ (new_pcs_insts, inst_env, local_inst_info, deriv_binds) ->
+ tcSetInstEnv inst_env $
- -- trace "tc3" $
- -- Typecheck the instance decls, includes deriving
- tcSetEnv env (
- -- trace "tcInstDecls:" $
- tcInstDecls1 unf_env decls mod_name rn_name_supply
- ) `thenTc` \ (inst_info, deriv_binds, ddump_deriv) ->
+ -- Default declarations
+ tcDefaults decls `thenTc` \ defaulting_tys ->
+ tcSetDefaultTys defaulting_tys $
- -- trace "tc4" $
- buildInstanceEnvs inst_info `thenTc` \ inst_mapper ->
+ -- Interface type signatures
+ -- We tie a knot so that the Ids read out of interfaces are in scope
+ -- when we read their pragmas.
+ -- What we rely on is that pragmas are typechecked lazily; if
+ -- any type errors are found (ie there's an inconsistency)
+ -- we silently discard the pragma
+ -- We must do this before mkImplicitDataBinds (which comes next), since
+ -- the latter looks up unpackCStringId, for example, which is usually
+ -- imported
+ tcInterfaceSigs unf_env decls `thenTc` \ sig_ids ->
+ tcExtendGlobalValEnv sig_ids $
- returnTc (inst_mapper, env, inst_info, deriv_binds, ddump_deriv)
+ -- Create any necessary record selector Ids and their bindings
+ -- "Necessary" includes data and newtype declarations
+ -- We don't create bindings for dictionary constructors;
+ -- they are always fully applied, and the bindings are just there
+ -- to support partial applications
+ mkImplicitDataBinds tycons `thenTc` \ (data_ids, imp_data_binds) ->
+ mkImplicitClassBinds classes `thenNF_Tc` \ (cls_ids, imp_cls_binds) ->
- -- End of inner fix loop
- ) `thenTc` \ (_, env, inst_info, deriv_binds, ddump_deriv) ->
+ -- Extend the global value environment with
+ -- (a) constructors
+ -- (b) record selectors
+ -- (c) class op selectors
+ -- (d) default-method ids... where? I can't see where these are
+ -- put into the envt, and I'm worried that the zonking phase
+ -- will find they aren't there and complain.
+ tcExtendGlobalValEnv data_ids $
+ tcExtendGlobalValEnv cls_ids $
- -- trace "tc5" $
- tcSetEnv env $
-
- -- Default declarations
- tcDefaults decls `thenTc` \ defaulting_tys ->
- tcSetDefaultTys defaulting_tys $
-
- -- Create any necessary record selector Ids and their bindings
- -- "Necessary" includes data and newtype declarations
- let
- tycons = getEnv_TyCons env
- classes = getEnv_Classes env
- in
- mkDataBinds tycons `thenTc` \ (data_ids, data_binds) ->
-
- -- Extend the global value environment with
- -- (a) constructors
- -- (b) record selectors
- -- (c) class op selectors
- -- (d) default-method ids
- tcExtendGlobalValEnv data_ids $
- tcExtendGlobalValEnv (concat (map classSelIds classes)) $
-
-
- -- Interface type signatures
- -- We tie a knot so that the Ids read out of interfaces are in scope
- -- when we read their pragmas.
- -- What we rely on is that pragmas are typechecked lazily; if
- -- any type errors are found (ie there's an inconsistency)
- -- we silently discard the pragma
- tcInterfaceSigs unf_env decls `thenTc` \ sig_ids ->
- tcExtendGlobalValEnv sig_ids $
-
-
- -- Value declarations next.
- -- We also typecheck any extra binds that came out of the "deriving" process
- -- trace "tcBinds:" $
- tcBindsAndThen
- (\ is_rec binds1 (binds2, thing) -> (binds1 `AndMonoBinds` binds2, thing))
- (get_val_decls decls `ThenBinds` deriv_binds)
- ( tcGetEnv `thenNF_Tc` \ env ->
- returnTc ((EmptyMonoBinds, env), emptyLIE)
- ) `thenTc` \ ((val_binds, final_env), lie_valdecls) ->
- tcSetEnv final_env $
-
-
- -- Second pass over class and instance declarations,
- -- to compile the bindings themselves.
- -- trace "tc8" $
- tcInstDecls2 inst_info `thenNF_Tc` \ (lie_instdecls, inst_binds) ->
- tcClassDecls2 decls `thenNF_Tc` \ (lie_clasdecls, cls_binds) ->
-
-
-
- -- Check that "main" has the right signature
- tcCheckMainSig mod_name `thenTc_`
-
- -- Deal 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. (Usually, ambiguous type variables are resolved
- -- during the generalisation step.)
- -- trace "tc9" $
- let
- lie_alldecls = lie_valdecls `plusLIE` lie_instdecls `plusLIE` lie_clasdecls
- in
- tcSimplifyTop lie_alldecls `thenTc` \ const_inst_binds ->
-
-
- -- Backsubstitution. This must be done last.
- -- Even tcCheckMainSig and tcSimplifyTop may do some unification.
- let
- all_binds = data_binds `AndMonoBinds`
- val_binds `AndMonoBinds`
- inst_binds `AndMonoBinds`
- cls_binds `AndMonoBinds`
- const_inst_binds
- in
- zonkTopBinds all_binds `thenNF_Tc` \ (all_binds', really_final_env) ->
-
- returnTc (really_final_env, (all_binds', inst_info, ddump_deriv))
-
- -- End of outer fix loop
- ) `thenTc` \ (final_env, (all_binds', inst_info, ddump_deriv)) ->
-
-
+ -- Foreign import declarations next
+ tcForeignImports decls `thenTc` \ (fo_ids, foi_decls) ->
+ tcExtendGlobalValEnv fo_ids $
+
+ -- Value declarations next.
+ -- We also typecheck any extra binds that came out of the "deriving" process
+ tcTopBinds (get_binds decls `ThenBinds` deriv_binds) `thenTc` \ ((val_binds, env), lie_valdecls) ->
+ tcSetEnv env $
+
+ -- Foreign export declarations next
+ tcForeignExports decls `thenTc` \ (lie_fodecls, foe_binds, foe_decls) ->
+
+ -- Second pass over class and instance declarations,
+ -- to compile the bindings themselves.
+ tcInstDecls2 local_inst_info `thenNF_Tc` \ (lie_instdecls, inst_binds) ->
+ tcClassDecls2 decls `thenNF_Tc` \ (lie_clasdecls, cls_dm_binds) ->
+ tcRules (pcs_rules pcs) decls `thenNF_Tc` \ (new_pcs_rules, lie_rules, local_rules) ->
+
+ -- Deal 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. (Usually, ambiguous type variables are resolved
+ -- during the generalisation step.)
let
- tycons = getEnv_TyCons final_env
- classes = getEnv_Classes final_env
-
- local_tycons = filter isLocallyDefined tycons
- local_classes = filter isLocallyDefined classes
+ lie_alldecls = lie_valdecls `plusLIE`
+ lie_instdecls `plusLIE`
+ lie_clasdecls `plusLIE`
+ lie_fodecls `plusLIE`
+ lie_rules
in
- -- FINISHED AT LAST
- returnTc (
- all_binds',
-
- local_tycons, local_classes, inst_info, tycon_specs,
+ tcSimplifyTop lie_alldecls `thenTc` \ const_inst_binds ->
+
+ -- Check that Main defines main
+ checkMain this_mod `thenTc_`
+
+ -- Backsubstitution. This must be done last.
+ -- Even tcSimplifyTop may do some unification.
+ let
+ all_binds = imp_data_binds `AndMonoBinds`
+ imp_cls_binds `AndMonoBinds`
+ val_binds `AndMonoBinds`
+ inst_binds `AndMonoBinds`
+ cls_dm_binds `AndMonoBinds`
+ const_inst_binds `AndMonoBinds`
+ foe_binds
+ in
+ zonkTopBinds all_binds `thenNF_Tc` \ (all_binds', final_env) ->
+ tcSetEnv final_env $
+ -- zonkTopBinds puts all the top-level Ids into the tcGEnv
+ zonkForeignExports foe_decls `thenNF_Tc` \ foe_decls' ->
+ zonkRules local_rules `thenNF_Tc` \ local_rules' ->
+
+
+ let groups :: FiniteMap Module TypeEnv
+ groups = groupTyThings (nameEnvElts (getTcGEnv final_env))
+
+ local_type_env :: TypeEnv
+ local_type_env = lookupWithDefaultFM groups emptyNameEnv this_mod
+
+ new_pst :: PackageSymbolTable
+ new_pst = extendTypeEnv (pcs_PST pcs) (delFromFM groups this_mod)
+
+ final_pcs :: PersistentCompilerState
+ final_pcs = pcs { pcs_PST = new_pst,
+ pcs_insts = new_pcs_insts,
+ pcs_rules = new_pcs_rules
+ }
+ in
+ returnTc (final_env,
+ TcResults { tc_pcs = final_pcs,
+ tc_env = local_type_env,
+ tc_binds = all_binds',
+ tc_insts = map iDFunId local_inst_info,
+ tc_fords = foi_decls ++ foe_decls',
+ tc_rules = rules'
+ })
+
+get_binds decls = foldr ThenBinds EmptyBinds [binds | ValD binds <- decls]
+\end{code}
- ddump_deriv
- )
-get_val_decls decls = foldr ThenBinds EmptyBinds [binds | ValD binds <- decls]
+\begin{code}
+checkMain :: Module -> TcM ()
+checkMain this_mod
+ | moduleName this_mod == mAIN_Name
+ = tcLookupGlobal_maybe mainName `thenNF_Tc` \ maybe_main ->
+ case maybe_main of
+ Just (AnId _) -> returnTc ()
+ other -> addErrTc noMainErr
+
+ | otherwise = returnTc ()
+
+noMainErr
+ = hsep [ptext SLIT("Module"), quotes (ppr mAIN_Name),
+ ptext SLIT("must include a definition for"), quotes (ptext SLIT("main"))]
\end{code}
-\begin{code}
-tcCheckMainSig mod_name
- | mod_name /= mAIN
- = returnTc () -- A non-main module
-
- | otherwise
- = -- Check that main is defined
- tcLookupTyCon ioTyCon_NAME `thenTc` \ (_,_,ioTyCon) ->
- tcLookupLocalValue main_NAME `thenNF_Tc` \ maybe_main_id ->
- case maybe_main_id of {
- Nothing -> failTc noMainErr;
- Just main_id ->
-
- -- Check that it has the right type (or a more general one)
- let expected_ty = applyTyCon ioTyCon [unitTy] in
- tcInstType [] expected_ty `thenNF_Tc` \ expected_tau ->
- tcId main_NAME `thenNF_Tc` \ (_, lie, main_tau) ->
- tcSetErrCtxt mainTyCheckCtxt $
- unifyTauTy expected_tau
- main_tau `thenTc_`
- checkTc (isEmptyBag lie) (mainTyMisMatch expected_ty (idType main_id))
- }
+%************************************************************************
+%* *
+\subsection{Dumping output}
+%* *
+%************************************************************************
-mainTyCheckCtxt sty
- = hsep [ptext SLIT("When checking that"), ppr sty main_NAME,
- ptext SLIT("has the required type")]
-
-noMainErr sty
- = hsep [ptext SLIT("Module"), pprModule sty mAIN,
- ptext SLIT("must include a definition for"), ppr sty main_NAME]
-
-mainTyMisMatch :: Type -> TcType s -> Error
-mainTyMisMatch expected actual sty
- = hang (hsep [ppr sty main_NAME, ptext SLIT("has the wrong type")])
- 4 (vcat [
- hsep [ptext SLIT("Expected:"), ppr sty expected],
- hsep [ptext SLIT("Inferred:"), ppr sty actual]
- ])
+\begin{code}
+printTcDump dflags Nothing = return ()
+printTcDump dflags (Just results)
+ = do dumpIfSet_dyn dflags Opt_D_dump_types
+ "Type signatures" (dump_sigs results)
+ dumpIfSet_dyn dflags Opt_D_dump_tc
+ "Typechecked" (dump_tc results)
+
+dump_tc results
+ = vcat [ppr (tc_binds results),
+ pp_rules (tc_rules results),
+ ppr_gen_tycons [tc | ATyCon tc <- nameEnvElts (tc_env results)]
+ ]
+
+dump_sigs results -- Print type signatures
+ = -- Convert to HsType so that we get source-language style printing
+ -- And sort by RdrName
+ vcat $ map ppr_sig $ sortLt lt_sig $
+ [(toRdrName id, toHsType (idType id))
+ | AnId id <- nameEnvElts (tc_env results),
+ want_sig id
+ ]
+ where
+ lt_sig (n1,_) (n2,_) = n1 < n2
+ ppr_sig (n,t) = ppr n <+> dcolon <+> ppr t
+
+ want_sig id | opt_PprStyle_Debug = True
+ | otherwise = isLocallyDefined n &&
+ isGlobalName n &&
+ not (isSysOcc (nameOccName n))
+ where
+ n = idName id
+
+ppr_gen_tycons tcs = vcat [ptext SLIT("{-# Generic type constructor details"),
+ vcat (map ppr_gen_tycon (filter isLocallyDefined tcs)),
+ ptext SLIT("#-}")
+ ]
+
+-- x&y are now Id's, not CoreExpr's
+ppr_gen_tycon tycon
+ | Just ep <- tyConGenInfo tycon
+ = (ppr tycon <> colon) $$ nest 4 (ppr_ep ep)
+
+ | otherwise = ppr tycon <> colon <+> ptext SLIT("Not derivable")
+
+ppr_ep (EP from to)
+ = vcat [ ptext SLIT("Rep type:") <+> ppr (funResultTy from_tau),
+ ptext SLIT("From:") <+> ppr (unfoldingTemplate (idUnfolding from)),
+ ptext SLIT("To:") <+> ppr (unfoldingTemplate (idUnfolding to))
+ ]
+ where
+ (_,from_tau) = splitForAllTys (idType from)
+
+pp_rules [] = empty
+pp_rules rs = vcat [ptext SLIT("{-# RULES"),
+ nest 4 (vcat (map ppr rs)),
+ ptext SLIT("#-}")]
\end{code}