X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Ftypecheck%2FTcEnv.lhs;h=cf86e56718eebfe79ffc5b1ca3fa0d34bc8d9198;hb=f714e6b642fd614a9971717045ae47c3d871275e;hp=bde67bacf5116a33ac4075f285963b5c42f10862;hpb=710e207487929c4a5977b5ee3bc6e539091953db;p=ghc-hetmet.git diff --git a/ghc/compiler/typecheck/TcEnv.lhs b/ghc/compiler/typecheck/TcEnv.lhs index bde67ba..cf86e56 100644 --- a/ghc/compiler/typecheck/TcEnv.lhs +++ b/ghc/compiler/typecheck/TcEnv.lhs @@ -1,766 +1,617 @@ \begin{code} module TcEnv( - TcId, TcIdSet, tcInstId, - tcLookupDataCon, - - TcEnv, ValueEnv, TyThing(..), TyThingDetails(..), tyThingKind, - - initEnv, getEnvTyCons, getEnvClasses, + TyThing(..), TcTyThing(..), TcId, + + -- Instance environment, and InstInfo type + InstInfo(..), pprInstInfo, pprInstInfoDetails, + simpleInstInfoTy, simpleInstInfoTyCon, + InstBindings(..), + + -- Global environment + tcExtendGlobalEnv, + tcExtendGlobalValEnv, + tcLookupLocatedGlobal, tcLookupGlobal, + tcLookupGlobalId, tcLookupTyCon, tcLookupClass, tcLookupDataCon, + tcLookupLocatedGlobalId, tcLookupLocatedTyCon, + tcLookupLocatedClass, tcLookupLocatedDataCon, - tcExtendUVarEnv, tcLookupUVar, + getInGlobalScope, - tcExtendKindEnv, tcExtendTyVarEnv, - tcExtendTyVarEnvForMeths, tcExtendTypeEnv, tcGetInScopeTyVars, + -- Local environment + tcExtendKindEnv, + tcExtendTyVarEnv, tcExtendTyVarEnv2, + tcExtendLocalValEnv, tcExtendLocalValEnv2, + tcLookup, tcLookupLocated, tcLookupLocalIds, + tcLookupId, tcLookupTyVar, + lclEnvElts, getInLocalScope, findGlobals, + wrongThingErr, - tcLookupTy, - tcLookupTyConByKey, - tcLookupClassByKey, tcLookupClassByKey_maybe, + tcExtendRecEnv, -- For knot-tying - tcExtendGlobalValEnv, tcExtendLocalValEnv, - tcGetValueEnv, tcSetValueEnv, - tcAddImportedIdInfo, + -- Rules + tcExtendRules, - tcLookupValue, tcLookupValueMaybe, - tcLookupValueByKey, tcLookupValueByKeyMaybe, - explicitLookupValueByKey, explicitLookupValue, - valueEnvIds, + -- Global type variables + tcGetGlobalTyVars, - newLocalId, newSpecPragmaId, - newDefaultMethodName, newDFunName, - tcGetGlobalTyVars, tcExtendGlobalTyVars, + -- Template Haskell stuff + checkWellStaged, spliceOK, bracketOK, tcMetaTy, thLevel, + topIdLvl, - InstEnv, emptyInstEnv, addToInstEnv, - lookupInstEnv, InstLookupResult(..), - tcGetInstEnv, tcSetInstEnv, classInstEnv, + -- Arrow stuff + checkProcLevel, - badCon, badPrimOp + -- New Ids + newLocalName, newDFunName ) where #include "HsVersions.h" -import Id ( mkUserLocal, isDataConWrapId_maybe ) -import MkId ( mkSpecPragmaId ) -import Var ( TyVar, Id, setVarName, - idType, lazySetIdInfo, idInfo, tyVarKind, UVar, - ) -import TcType ( TcType, TcTyVar, TcTyVarSet, TcThetaType, - tcInstTyVars, zonkTcTyVars, - TcKind, - ) -import VarSet -import Type ( Kind, Type, superKind, - tyVarsOfType, tyVarsOfTypes, - splitForAllTys, splitRhoTy, splitFunTys, - splitAlgTyConApp_maybe, getTyVar, getDFunTyKey - ) -import Subst ( substTy ) -import UsageSPUtils ( unannotTy ) -import DataCon ( DataCon ) -import TyCon ( TyCon, tyConKind, tyConArity, isSynTyCon ) -import Class ( Class, ClassOpItem, ClassContext, classTyCon ) - -import TcMonad - -import IdInfo ( vanillaIdInfo ) -import Name ( Name, OccName, Provenance(..), ExportFlag(..), NamedThing(..), - nameOccName, nameModule, getSrcLoc, mkGlobalName, - maybeWiredInTyConName, maybeWiredInIdName, isLocallyDefined, - NameEnv, emptyNameEnv, lookupNameEnv, nameEnvElts, - extendNameEnv, extendNameEnvList +import HsSyn ( LRuleDecl, LHsBinds, LSig ) +import TcIface ( tcImportDecl ) +import TcRnMonad +import TcMType ( zonkTcType, zonkTcTyVar, zonkTcTyVarsAndFV ) +import TcType ( Type, TcKind, TcTyVar, TcTyVarSet, + tyVarsOfType, tyVarsOfTypes, tcSplitDFunTy, mkGenTyConApp, + getDFunTyKey, tcTyConAppTyCon, tyVarBindingInfo, + tidyOpenType, tidyOpenTyVar ) -import OccName ( mkDFunOcc, mkDefaultMethodOcc, occNameString ) -import Module ( Module ) -import Unify ( unifyTyListsX, matchTys ) -import Unique ( pprUnique10, Unique, Uniquable(..) ) -import UniqFM -import Unique ( Uniquable(..) ) -import Util ( zipEqual, zipWith3Equal, mapAccumL ) -import VarEnv ( TyVarSubstEnv ) -import SrcLoc ( SrcLoc ) -import FastString ( FastString ) -import Maybes +import qualified Type ( getTyVar_maybe ) +import Id ( idName, isLocalId ) +import Var ( TyVar, Id, idType ) +import VarSet +import VarEnv +import RdrName ( extendLocalRdrEnv ) +import DataCon ( DataCon ) +import TyCon ( TyCon ) +import Class ( Class ) +import Name ( Name, NamedThing(..), getSrcLoc, mkInternalName, nameIsLocalOrFrom ) +import NameEnv +import OccName ( mkDFunOcc, occNameString ) +import HscTypes ( DFunId, extendTypeEnvList, lookupType, + TyThing(..), tyThingId, tyThingDataCon, + ExternalPackageState(..) ) + +import SrcLoc ( SrcLoc, Located(..) ) import Outputable +import Maybe ( isJust ) \end{code} + %************************************************************************ %* * -\subsection{TcId} +%* tcLookupGlobal * %* * %************************************************************************ +Using the Located versions (eg. tcLookupLocatedGlobal) is preferred, +unless you know that the SrcSpan in the monad is already set to the +span of the Name. \begin{code} -type TcId = Id -- Type may be a TcType -type TcIdSet = IdSet +tcLookupLocatedGlobal :: Located Name -> TcM TyThing +-- c.f. IfaceEnvEnv.tcIfaceGlobal +tcLookupLocatedGlobal name + = addLocM tcLookupGlobal name + +tcLookupGlobal :: Name -> TcM TyThing +tcLookupGlobal name + = do { env <- getGblEnv + ; if nameIsLocalOrFrom (tcg_mod env) name + + then -- It's defined in this module + case lookupNameEnv (tcg_type_env env) name of + Just thing -> return thing + Nothing -> notFound "tcLookupGlobal" name + + else do -- It's imported + { eps <- getEps + ; hpt <- getHpt + ; case lookupType hpt (eps_PTE eps) name of + Just thing -> return thing + Nothing -> do { traceIf (text "tcLookupGlobal" <+> ppr name) + ; initIfaceTcRn (tcImportDecl name) } + }} +\end{code} + +\begin{code} +tcLookupGlobalId :: Name -> TcM Id +-- Never used for Haskell-source DataCons, hence no ADataCon case +tcLookupGlobalId name + = tcLookupGlobal name `thenM` \ thing -> + return (tyThingId thing) -tcLookupDataCon :: Name -> TcM s (DataCon, [TcType], TcType) +tcLookupDataCon :: Name -> TcM DataCon tcLookupDataCon con_name - = tcLookupValue con_name `thenNF_Tc` \ con_id -> - case isDataConWrapId_maybe con_id of { - Nothing -> failWithTc (badCon con_id); - Just data_con -> - - tcInstId con_id `thenNF_Tc` \ (_, _, con_tau) -> - -- Ignore the con_theta; overloaded constructors only - -- behave differently when called, not when used for - -- matching. - let - (arg_tys, result_ty) = splitFunTys con_tau - in - ASSERT( maybeToBool (splitAlgTyConApp_maybe result_ty) ) - returnTc (data_con, arg_tys, result_ty) } - --- A useful function that takes an occurrence of a global thing --- and instantiates its type with fresh type variables -tcInstId :: Id - -> NF_TcM s ([TcTyVar], -- It's instantiated type - TcThetaType, -- - TcType) -- -tcInstId id - = let - (tyvars, rho) = splitForAllTys (unannotTy (idType id)) - in - tcInstTyVars tyvars `thenNF_Tc` \ (tyvars', arg_tys, tenv) -> - let - rho' = substTy tenv rho - (theta', tau') = splitRhoTy rho' - in - returnNF_Tc (tyvars', theta', tau') -\end{code} + = tcLookupGlobal con_name `thenM` \ thing -> + return (tyThingDataCon thing) + +tcLookupClass :: Name -> TcM Class +tcLookupClass name + = tcLookupGlobal name `thenM` \ thing -> + case thing of + AClass cls -> return cls + other -> wrongThingErr "class" (AGlobal thing) name + +tcLookupTyCon :: Name -> TcM TyCon +tcLookupTyCon name + = tcLookupGlobal name `thenM` \ thing -> + case thing of + ATyCon tc -> return tc + other -> wrongThingErr "type constructor" (AGlobal thing) name + +tcLookupLocatedGlobalId :: Located Name -> TcM Id +tcLookupLocatedGlobalId = addLocM tcLookupId -Between the renamer and the first invocation of the UsageSP inference, -identifiers read from interface files will have usage information in -their types, whereas other identifiers will not. The unannotTy here -in @tcInstId@ prevents this information from pointlessly propagating -further prior to the first usage inference. +tcLookupLocatedDataCon :: Located Name -> TcM DataCon +tcLookupLocatedDataCon = addLocM tcLookupDataCon +tcLookupLocatedClass :: Located Name -> TcM Class +tcLookupLocatedClass = addLocM tcLookupClass + +tcLookupLocatedTyCon :: Located Name -> TcM TyCon +tcLookupLocatedTyCon = addLocM tcLookupTyCon +\end{code} %************************************************************************ %* * -\subsection{TcEnv} + Extending the global environment %* * %************************************************************************ -Data type declarations -~~~~~~~~~~~~~~~~~~~~~ \begin{code} -data TcEnv = TcEnv - UsageEnv - TypeEnv - ValueEnv - InstEnv - (TcTyVarSet, -- The in-scope TyVars - TcRef TcTyVarSet) -- Free type variables of the value env - -- ...why mutable? see notes with tcGetGlobalTyVars - -- Includes the in-scope tyvars - -type UsageEnv = NameEnv UVar -type TypeEnv = NameEnv TyThing -type ValueEnv = NameEnv Id - -valueEnvIds :: ValueEnv -> [Id] -valueEnvIds ve = nameEnvElts ve - -data TyThing = ATyVar TyVar - | ATyCon TyCon - | AClass Class - | AThing TcKind -- Used temporarily, during kind checking --- For example, when checking (forall a. T a Int): --- 1. We first bind (a -> AThink kv), where kv is a kind variable. --- 2. Then we kind-check the (T a Int) part. --- 3. Then we zonk the kind variable. --- 4. Now we know the kind for 'a', and we add (a -> ATyVar a::K) to the environment - -tyThingKind :: TyThing -> TcKind -tyThingKind (ATyVar tv) = tyVarKind tv -tyThingKind (ATyCon tc) = tyConKind tc -tyThingKind (AClass cl) = tyConKind (classTyCon cl) -- For some odd reason, - -- a class doesn't include its kind -tyThingKind (AThing k) = k - -data TyThingDetails = SynTyDetails Type - | DataTyDetails ClassContext [DataCon] [Class] - | ClassDetails ClassContext [Id] [ClassOpItem] DataCon - -initEnv :: TcRef TcTyVarSet -> TcEnv -initEnv mut = TcEnv emptyNameEnv emptyNameEnv emptyNameEnv emptyInstEnv (emptyVarSet, mut) - -getEnvClasses (TcEnv _ te _ _ _) = [cl | AClass cl <- nameEnvElts te] -getEnvTyCons (TcEnv _ te _ _ _) = [tc | ATyCon tc <- nameEnvElts te] +tcExtendGlobalEnv :: [TyThing] -> TcM r -> TcM r + -- Given a mixture of Ids, TyCons, Classes, all from the + -- module being compiled, extend the global environment +tcExtendGlobalEnv things thing_inside + = do { env <- getGblEnv + ; let ge' = extendTypeEnvList (tcg_type_env env) things + ; setGblEnv (env {tcg_type_env = ge'}) thing_inside } + +tcExtendGlobalValEnv :: [Id] -> TcM a -> TcM a + -- Same deal as tcExtendGlobalEnv, but for Ids +tcExtendGlobalValEnv ids thing_inside + = tcExtendGlobalEnv [AnId id | id <- ids] thing_inside \end{code} -%************************************************************************ -%* * -\subsection{The usage environment} -%* * -%************************************************************************ - -Extending the usage environment +A variety of global lookups, when we know what we are looking for. \begin{code} -tcExtendUVarEnv :: Name -> UVar -> TcM s r -> TcM s r -tcExtendUVarEnv uv_name uv scope - = tcGetEnv `thenNF_Tc` \ (TcEnv ue te ve ie gtvs) -> - tcSetEnv (TcEnv (extendNameEnv ue uv_name uv) te ve ie gtvs) scope +getInGlobalScope :: TcM (Name -> Bool) +-- Get all things in the global environment; used for deciding what +-- rules to suck in. Anything defined in this module (nameIsLocalOrFrom) +-- is certainly in the envt, so we don't bother to look. +getInGlobalScope + = do { mod <- getModule + ; eps <- getEps + ; hpt <- getHpt + ; return (\n -> nameIsLocalOrFrom mod n || + isJust (lookupType hpt (eps_PTE eps) n)) } \end{code} -Looking up in the environments. \begin{code} -tcLookupUVar :: Name -> NF_TcM s UVar -tcLookupUVar uv_name - = tcGetEnv `thenNF_Tc` \ (TcEnv ue te ve _ gtvs) -> - case lookupNameEnv ue uv_name of - Just uv -> returnNF_Tc uv - Nothing -> failWithTc (uvNameOutOfScope uv_name) -\end{code} +tcExtendRecEnv :: [(Name,TyThing)] -> TcM r -> TcM r +-- Extend the global environments for the type/class knot tying game +tcExtendRecEnv gbl_stuff thing_inside + = updGblEnv upd thing_inside + where + upd env = env { tcg_type_env = extend (tcg_type_env env) } + extend env = extendNameEnvList env gbl_stuff +\end{code} %************************************************************************ %* * -\subsection{The type environment} +\subsection{The local environment} %* * %************************************************************************ \begin{code} -tcExtendKindEnv :: [(Name,TcKind)] -> TcM s r -> TcM s r -tcExtendKindEnv pairs scope - = tcGetEnv `thenNF_Tc` \ (TcEnv ue te ve ie gtvs) -> - let - te' = extendNameEnvList te [(n, AThing k) | (n,k) <- pairs] - -- No need to extend global tyvars for kind checking - in - tcSetEnv (TcEnv ue te' ve ie gtvs) scope - -tcExtendTyVarEnv :: [TyVar] -> TcM s r -> TcM s r -tcExtendTyVarEnv tyvars scope - = tcGetEnv `thenNF_Tc` \ (TcEnv ue te ve ie (in_scope_tvs, gtvs)) -> +tcLookupLocated :: Located Name -> TcM TcTyThing +tcLookupLocated = addLocM tcLookup + +tcLookup :: Name -> TcM TcTyThing +tcLookup name + = getLclEnv `thenM` \ local_env -> + case lookupNameEnv (tcl_env local_env) name of + Just thing -> returnM thing + Nothing -> tcLookupGlobal name `thenM` \ thing -> + returnM (AGlobal thing) + +tcLookupTyVar :: Name -> TcM Id +tcLookupTyVar name + = tcLookup name `thenM` \ thing -> + case thing of + ATyVar tv -> returnM tv + other -> pprPanic "tcLookupTyVar" (ppr name) + +tcLookupId :: Name -> TcM Id +-- Used when we aren't interested in the binding level +-- Never a DataCon. (Why does that matter? see TcExpr.tcId) +tcLookupId name + = tcLookup name `thenM` \ thing -> + case thing of + ATcId tc_id _ _ -> returnM tc_id + AGlobal (AnId id) -> returnM id + other -> pprPanic "tcLookupId" (ppr name) + +tcLookupLocalIds :: [Name] -> TcM [TcId] +-- We expect the variables to all be bound, and all at +-- the same level as the lookup. Only used in one place... +tcLookupLocalIds ns + = getLclEnv `thenM` \ env -> + returnM (map (lookup (tcl_env env) (thLevel (tcl_th_ctxt env))) ns) + where + lookup lenv lvl name + = case lookupNameEnv lenv name of + Just (ATcId id lvl1 _) -> ASSERT( lvl == lvl1 ) id + other -> pprPanic "tcLookupLocalIds" (ppr name) + +lclEnvElts :: TcLclEnv -> [TcTyThing] +lclEnvElts env = nameEnvElts (tcl_env env) + +getInLocalScope :: TcM (Name -> Bool) + -- Ids only +getInLocalScope = getLclEnv `thenM` \ env -> + let + lcl_env = tcl_env env + in + return (`elemNameEnv` lcl_env) +\end{code} + +\begin{code} +tcExtendKindEnv :: [(Name, TcKind)] -> TcM r -> TcM r +tcExtendKindEnv things thing_inside + = updLclEnv upd thing_inside + where + upd lcl_env = lcl_env { tcl_env = extend (tcl_env lcl_env) } + extend env = extendNameEnvList env [(n, AThing k) | (n,k) <- things] + +tcExtendTyVarEnv :: [TyVar] -> TcM r -> TcM r +tcExtendTyVarEnv tvs thing_inside + = tc_extend_tv_env [(getName tv, ATyVar tv) | tv <- tvs] tvs thing_inside + +tcExtendTyVarEnv2 :: [(TyVar,TcTyVar)] -> TcM r -> TcM r +tcExtendTyVarEnv2 tv_pairs thing_inside + = tc_extend_tv_env [(getName tv1, ATyVar tv2) | (tv1,tv2) <- tv_pairs] + [tv | (_,tv) <- tv_pairs] + thing_inside + +tc_extend_tv_env binds tyvars thing_inside + = getLclEnv `thenM` \ env@(TcLclEnv {tcl_env = le, + tcl_tyvars = gtvs, + tcl_rdr = rdr_env}) -> let - te' = extendNameEnvList te [ (getName tv, ATyVar tv) | tv <- tyvars] - new_tv_set = mkVarSet tyvars - in_scope_tvs' = in_scope_tvs `unionVarSet` new_tv_set + le' = extendNameEnvList le binds + rdr_env' = extendLocalRdrEnv rdr_env (map fst binds) + new_tv_set = mkVarSet tyvars in -- It's important to add the in-scope tyvars to the global tyvar set -- as well. Consider - -- f (x::r) = let g y = y::r in ... + -- f (_::r) = let g y = y::r in ... -- Here, g mustn't be generalised. This is also important during -- class and instance decls, when we mustn't generalise the class tyvars -- when typechecking the methods. - tc_extend_gtvs gtvs new_tv_set `thenNF_Tc` \ gtvs' -> - tcSetEnv (TcEnv ue te' ve ie (in_scope_tvs', gtvs')) scope - --- This variant, tcExtendTyVarEnvForMeths, takes *two* bunches of tyvars: --- the signature tyvars contain the original names --- the instance tyvars are what those names should be mapped to --- It's needed when typechecking the method bindings of class and instance decls --- It does *not* extend the global tyvars; tcMethodBind does that for itself - -tcExtendTyVarEnvForMeths :: [TyVar] -> [TcTyVar] -> TcM s r -> TcM s r -tcExtendTyVarEnvForMeths sig_tyvars inst_tyvars thing_inside - = tcGetEnv `thenNF_Tc` \ (TcEnv ue te ve ie gtvs) -> - let - te' = extendNameEnvList te stuff - in - tcSetEnv (TcEnv ue te' ve ie gtvs) thing_inside - where - stuff = [ (getName sig_tv, ATyVar inst_tv) - | (sig_tv, inst_tv) <- zipEqual "tcMeth" sig_tyvars inst_tyvars - ] - -tcExtendGlobalTyVars extra_global_tvs scope - = tcGetEnv `thenNF_Tc` \ (TcEnv ue te ve ie (in_scope,gtvs)) -> - tc_extend_gtvs gtvs extra_global_tvs `thenNF_Tc` \ gtvs' -> - tcSetEnv (TcEnv ue te ve ie (in_scope,gtvs')) scope - -tc_extend_gtvs gtvs extra_global_tvs - = tcReadMutVar gtvs `thenNF_Tc` \ global_tvs -> - let - new_global_tyvars = global_tvs `unionVarSet` extra_global_tvs - in - tcNewMutVar new_global_tyvars + tc_extend_gtvs gtvs new_tv_set `thenM` \ gtvs' -> + setLclEnv (env {tcl_env = le', tcl_tyvars = gtvs', tcl_rdr = rdr_env'}) thing_inside \end{code} -@tcGetGlobalTyVars@ returns a fully-zonked set of tyvars free in the environment. -To improve subsequent calls to the same function it writes the zonked set back into -the environment. \begin{code} -tcGetGlobalTyVars :: NF_TcM s TcTyVarSet -tcGetGlobalTyVars - = tcGetEnv `thenNF_Tc` \ (TcEnv ue te ve ie (_,gtvs)) -> - tcReadMutVar gtvs `thenNF_Tc` \ global_tvs -> - zonkTcTyVars (varSetElems global_tvs) `thenNF_Tc` \ global_tys' -> +tcExtendLocalValEnv :: [TcId] -> TcM a -> TcM a +tcExtendLocalValEnv ids thing_inside + = getLclEnv `thenM` \ env -> let - global_tvs' = (tyVarsOfTypes global_tys') + extra_global_tyvars = tyVarsOfTypes [idType id | id <- ids] + th_lvl = thLevel (tcl_th_ctxt env) + proc_lvl = proc_level (tcl_arrow_ctxt env) + extra_env = [(idName id, ATcId id th_lvl proc_lvl) | id <- ids] + le' = extendNameEnvList (tcl_env env) extra_env + rdr_env' = extendLocalRdrEnv (tcl_rdr env) (map idName ids) in - tcWriteMutVar gtvs global_tvs' `thenNF_Tc_` - returnNF_Tc global_tvs' - -tcGetInScopeTyVars :: NF_TcM s [TcTyVar] -tcGetInScopeTyVars - = tcGetEnv `thenNF_Tc` \ (TcEnv ue te ve ie (in_scope_tvs, gtvs)) -> - returnNF_Tc (varSetElems in_scope_tvs) -\end{code} + tc_extend_gtvs (tcl_tyvars env) extra_global_tyvars `thenM` \ gtvs' -> + setLclEnv (env {tcl_env = le', tcl_tyvars = gtvs', tcl_rdr = rdr_env'}) thing_inside - -Type constructors and classes - -\begin{code} -tcExtendTypeEnv :: [(Name, TyThing)] -> TcM s r -> TcM s r -tcExtendTypeEnv bindings scope - = ASSERT( null [tv | (_, ATyVar tv) <- bindings] ) - -- Not for tyvars; use tcExtendTyVarEnv - tcGetEnv `thenNF_Tc` \ (TcEnv ue te ve ie gtvs) -> +tcExtendLocalValEnv2 :: [(Name,TcId)] -> TcM a -> TcM a +tcExtendLocalValEnv2 names_w_ids thing_inside + = getLclEnv `thenM` \ env -> let - te' = extendNameEnvList te bindings + extra_global_tyvars = tyVarsOfTypes [idType id | (name,id) <- names_w_ids] + th_lvl = thLevel (tcl_th_ctxt env) + proc_lvl = proc_level (tcl_arrow_ctxt env) + extra_env = [(name, ATcId id th_lvl proc_lvl) | (name,id) <- names_w_ids] + le' = extendNameEnvList (tcl_env env) extra_env + rdr_env' = extendLocalRdrEnv (tcl_rdr env) (map fst names_w_ids) in - tcSetEnv (TcEnv ue te' ve ie gtvs) scope + tc_extend_gtvs (tcl_tyvars env) extra_global_tyvars `thenM` \ gtvs' -> + setLclEnv (env {tcl_env = le', tcl_tyvars = gtvs', tcl_rdr = rdr_env'}) thing_inside \end{code} -Looking up in the environments. - \begin{code} -tcLookupTy :: Name -> NF_TcM s TyThing -tcLookupTy name - = tcGetEnv `thenNF_Tc` \ (TcEnv ue te ve ie gtvs) -> - case lookupNameEnv te name of { - Just thing -> returnNF_Tc thing ; - Nothing -> - - case maybeWiredInTyConName name of - Just tc -> returnNF_Tc (ATyCon tc) - - Nothing -> -- This can happen if an interface-file - -- unfolding is screwed up - failWithTc (tyNameOutOfScope name) - } +----------------------- +-- findGlobals looks at the value environment and finds values +-- whose types mention the offending type variable. It has to be +-- careful to zonk the Id's type first, so it has to be in the monad. +-- We must be careful to pass it a zonked type variable, too. + +findGlobals :: TcTyVarSet + -> TidyEnv + -> TcM (TidyEnv, [SDoc]) + +findGlobals tvs tidy_env + = getLclEnv `thenM` \ lcl_env -> + go tidy_env [] (lclEnvElts lcl_env) + where + go tidy_env acc [] = returnM (tidy_env, acc) + go tidy_env acc (thing : things) + = find_thing ignore_it tidy_env thing `thenM` \ (tidy_env1, maybe_doc) -> + case maybe_doc of + Just d -> go tidy_env1 (d:acc) things + Nothing -> go tidy_env1 acc things + + ignore_it ty = not (tvs `intersectsVarSet` tyVarsOfType ty) + +----------------------- +find_thing ignore_it tidy_env (ATcId id _ _) + = zonkTcType (idType id) `thenM` \ id_ty -> + if ignore_it id_ty then + returnM (tidy_env, Nothing) + else let + (tidy_env', tidy_ty) = tidyOpenType tidy_env id_ty + msg = sep [ppr id <+> dcolon <+> ppr tidy_ty, + nest 2 (parens (ptext SLIT("bound at") <+> + ppr (getSrcLoc id)))] + in + returnM (tidy_env', Just msg) + +find_thing ignore_it tidy_env (ATyVar tv) + = zonkTcTyVar tv `thenM` \ tv_ty -> + if ignore_it tv_ty then + returnM (tidy_env, Nothing) + else let + (tidy_env1, tv1) = tidyOpenTyVar tidy_env tv + (tidy_env2, tidy_ty) = tidyOpenType tidy_env1 tv_ty + msg = sep [ppr tv1 <+> eq_stuff, nest 2 bound_at] + + eq_stuff | Just tv' <- Type.getTyVar_maybe tv_ty, + tv == tv' = empty + | otherwise = equals <+> ppr tidy_ty + -- It's ok to use Type.getTyVar_maybe because ty is zonked by now -tcLookupClassByKey :: Unique -> NF_TcM s Class -tcLookupClassByKey key - = tcGetEnv `thenNF_Tc` \ (TcEnv ue te ve ie gtvs) -> - case lookupUFM_Directly te key of - Just (AClass cl) -> returnNF_Tc cl - other -> pprPanic "tcLookupClassByKey:" (pprUnique10 key) - -tcLookupClassByKey_maybe :: Unique -> NF_TcM s (Maybe Class) -tcLookupClassByKey_maybe key - = tcGetEnv `thenNF_Tc` \ (TcEnv ue te ve ie gtvs) -> - case lookupUFM_Directly te key of - Just (AClass cl) -> returnNF_Tc (Just cl) - other -> returnNF_Tc Nothing - -tcLookupTyConByKey :: Unique -> NF_TcM s TyCon -tcLookupTyConByKey key - = tcGetEnv `thenNF_Tc` \ (TcEnv ue te ve ie gtvs) -> - case lookupUFM_Directly te key of - Just (ATyCon tc) -> returnNF_Tc tc - other -> pprPanic "tcLookupTyConByKey:" (pprUnique10 key) + bound_at = tyVarBindingInfo tv + in + returnM (tidy_env2, Just msg) \end{code} - - %************************************************************************ %* * -\subsection{The value environment} +\subsection{The global tyvars} %* * %************************************************************************ \begin{code} -tcExtendGlobalValEnv :: [Id] -> TcM s a -> TcM s a -tcExtendGlobalValEnv ids scope - = tcGetEnv `thenNF_Tc` \ (TcEnv ue te ve ie gtvs) -> - let - ve' = addListToUFM_Directly ve [(getUnique id, id) | id <- ids] - in - tcSetEnv (TcEnv ue te ve' ie gtvs) scope - -tcExtendLocalValEnv :: [(Name,TcId)] -> TcM s a -> TcM s a -tcExtendLocalValEnv names_w_ids scope - = tcGetEnv `thenNF_Tc` \ (TcEnv ue te ve ie (in_scope_tvs,gtvs)) -> - tcReadMutVar gtvs `thenNF_Tc` \ global_tvs -> - let - ve' = extendNameEnvList ve names_w_ids - extra_global_tyvars = tyVarsOfTypes (map (idType . snd) names_w_ids) - in - tc_extend_gtvs gtvs extra_global_tyvars `thenNF_Tc` \ gtvs' -> - tcSetEnv (TcEnv ue te ve' ie (in_scope_tvs,gtvs')) scope +tc_extend_gtvs gtvs extra_global_tvs + = readMutVar gtvs `thenM` \ global_tvs -> + newMutVar (global_tvs `unionVarSet` extra_global_tvs) \end{code} +@tcGetGlobalTyVars@ returns a fully-zonked set of tyvars free in the environment. +To improve subsequent calls to the same function it writes the zonked set back into +the environment. \begin{code} -tcLookupValue :: Name -> NF_TcM s Id -- Panics if not found -tcLookupValue name - = case maybeWiredInIdName name of - Just id -> returnNF_Tc id - Nothing -> tcGetEnv `thenNF_Tc` \ (TcEnv ue te ve ie gtvs) -> - returnNF_Tc (lookupWithDefaultUFM ve def name) - where - wired_in = case maybeWiredInIdName name of - Just id -> True - Nothing -> False - def = pprPanic "tcLookupValue:" (ppr name <+> ppr wired_in) - -tcLookupValueMaybe :: Name -> NF_TcM s (Maybe Id) -tcLookupValueMaybe name - = case maybeWiredInIdName name of - Just id -> returnNF_Tc (Just id) - Nothing -> tcGetEnv `thenNF_Tc` \ (TcEnv ue te ve ie gtvs) -> - returnNF_Tc (lookupNameEnv ve name) - -tcLookupValueByKey :: Unique -> NF_TcM s Id -- Panics if not found -tcLookupValueByKey key - = tcGetEnv `thenNF_Tc` \ (TcEnv ue te ve ie gtvs) -> - returnNF_Tc (explicitLookupValueByKey ve key) - -tcLookupValueByKeyMaybe :: Unique -> NF_TcM s (Maybe Id) -tcLookupValueByKeyMaybe key - = tcGetEnv `thenNF_Tc` \ (TcEnv ue te ve ie gtvs) -> - returnNF_Tc (lookupUFM_Directly ve key) - -tcGetValueEnv :: NF_TcM s ValueEnv -tcGetValueEnv - = tcGetEnv `thenNF_Tc` \ (TcEnv ue te ve ie gtvs) -> - returnNF_Tc ve - - -tcSetValueEnv :: ValueEnv -> TcM s a -> TcM s a -tcSetValueEnv ve scope - = tcGetEnv `thenNF_Tc` \ (TcEnv ue te _ ie gtvs) -> - tcSetEnv (TcEnv ue te ve ie gtvs) scope - --- Non-monadic version, environment given explicitly -explicitLookupValueByKey :: ValueEnv -> Unique -> Id -explicitLookupValueByKey ve key - = lookupWithDefaultUFM_Directly ve def key - where - def = pprPanic "lookupValueByKey:" (pprUnique10 key) - -explicitLookupValue :: ValueEnv -> Name -> Maybe Id -explicitLookupValue ve name - = case maybeWiredInIdName name of - Just id -> Just id - Nothing -> lookupNameEnv ve name - - -- Extract the IdInfo from an IfaceSig imported from an interface file -tcAddImportedIdInfo :: ValueEnv -> Id -> Id -tcAddImportedIdInfo unf_env id - | isLocallyDefined id -- Don't look up locally defined Ids, because they - -- have explicit local definitions, so we get a black hole! - = id - | otherwise - = id `lazySetIdInfo` new_info - -- The Id must be returned without a data dependency on maybe_id - where - new_info = case explicitLookupValue unf_env (getName id) of - Nothing -> vanillaIdInfo - Just imported_id -> idInfo imported_id - -- ToDo: could check that types are the same +tcGetGlobalTyVars :: TcM TcTyVarSet +tcGetGlobalTyVars + = getLclEnv `thenM` \ (TcLclEnv {tcl_tyvars = gtv_var}) -> + readMutVar gtv_var `thenM` \ gbl_tvs -> + zonkTcTyVarsAndFV (varSetElems gbl_tvs) `thenM` \ gbl_tvs' -> + writeMutVar gtv_var gbl_tvs' `thenM_` + returnM gbl_tvs' \end{code} -Constructing new Ids + +%************************************************************************ +%* * +\subsection{Rules} +%* * +%************************************************************************ \begin{code} -newLocalId :: OccName -> TcType -> SrcLoc -> NF_TcM s TcId -newLocalId name ty loc - = tcGetUnique `thenNF_Tc` \ uniq -> - returnNF_Tc (mkUserLocal name uniq ty loc) - -newSpecPragmaId :: Name -> TcType -> NF_TcM s TcId -newSpecPragmaId name ty - = tcGetUnique `thenNF_Tc` \ uniq -> - returnNF_Tc (mkSpecPragmaId (nameOccName name) uniq ty (getSrcLoc name)) +tcExtendRules :: [LRuleDecl Id] -> TcM a -> TcM a + -- Just pop the new rules into the EPS and envt resp + -- All the rules come from an interface file, not soruce + -- Nevertheless, some may be for this module, if we read + -- its interface instead of its source code +tcExtendRules lcl_rules thing_inside + = do { env <- getGblEnv + ; let + env' = env { tcg_rules = lcl_rules ++ tcg_rules env } + ; setGblEnv env' thing_inside } \end{code} %************************************************************************ %* * -\subsection{The instance environment} + Arrow notation proc levels %* * %************************************************************************ \begin{code} -tcGetInstEnv :: NF_TcM s InstEnv -tcGetInstEnv = tcGetEnv `thenNF_Tc` \ (TcEnv ue te ve ie (_,gtvs)) -> - returnNF_Tc ie - -tcSetInstEnv :: InstEnv -> TcM s a -> TcM s a -tcSetInstEnv ie scope - = tcGetEnv `thenNF_Tc` \ (TcEnv ue te ve _ gtvs) -> - tcSetEnv (TcEnv ue te ve ie gtvs) scope -\end{code} +checkProcLevel :: TcId -> ProcLevel -> TcM () +checkProcLevel id id_lvl + = do { banned <- getBannedProcLevels + ; checkTc (not (id_lvl `elem` banned)) + (procLevelErr id id_lvl) } + +procLevelErr id id_lvl + = hang (ptext SLIT("Command-bound variable") <+> quotes (ppr id) <+> ptext SLIT("is not in scope here")) + 4 (ptext SLIT("Reason: it is used in the left argument of (-<)")) +\end{code} + +%************************************************************************ +%* * + Meta level +%* * +%************************************************************************ \begin{code} -type InstEnv = UniqFM ClsInstEnv -- Maps Class to instances for that class -type ClsInstEnv = [(TyVarSet, [Type], Id)] -- The instances for a particular class - -classInstEnv :: InstEnv -> Class -> ClsInstEnv -classInstEnv env cls = lookupWithDefaultUFM env [] cls +instance Outputable ThStage where + ppr Comp = text "Comp" + ppr (Brack l _ _) = text "Brack" <+> int l + ppr (Splice l) = text "Splice" <+> int l + + +thLevel :: ThStage -> ThLevel +thLevel Comp = topLevel +thLevel (Splice l) = l +thLevel (Brack l _ _) = l + + +checkWellStaged :: SDoc -- What the stage check is for + -> ThLevel -- Binding level + -> ThStage -- Use stage + -> TcM () -- Fail if badly staged, adding an error +checkWellStaged pp_thing bind_lvl use_stage + | bind_lvl <= use_lvl -- OK! + = returnM () + + | bind_lvl == topLevel -- GHC restriction on top level splices + = failWithTc $ + sep [ptext SLIT("GHC stage restriction:") <+> pp_thing, + nest 2 (ptext SLIT("is used in a top-level splice, and must be imported, not defined locally"))] + + | otherwise -- Badly staged + = failWithTc $ + ptext SLIT("Stage error:") <+> pp_thing <+> + hsep [ptext SLIT("is bound at stage") <+> ppr bind_lvl, + ptext SLIT("but used at stage") <+> ppr use_lvl] + where + use_lvl = thLevel use_stage + + +topIdLvl :: Id -> ThLevel +-- Globals may either be imported, or may be from an earlier "chunk" +-- (separated by declaration splices) of this module. The former +-- *can* be used inside a top-level splice, but the latter cannot. +-- Hence we give the former impLevel, but the latter topLevel +-- E.g. this is bad: +-- x = [| foo |] +-- $( f x ) +-- By the time we are prcessing the $(f x), the binding for "x" +-- will be in the global env, not the local one. +topIdLvl id | isLocalId id = topLevel + | otherwise = impLevel + +-- Indicates the legal transitions on bracket( [| |] ). +bracketOK :: ThStage -> Maybe ThLevel +bracketOK (Brack _ _ _) = Nothing -- Bracket illegal inside a bracket +bracketOK stage = (Just (thLevel stage + 1)) + +-- Indicates the legal transitions on splice($). +spliceOK :: ThStage -> Maybe ThLevel +spliceOK (Splice _) = Nothing -- Splice illegal inside splice +spliceOK stage = Just (thLevel stage - 1) + +tcMetaTy :: Name -> TcM Type +-- Given the name of a Template Haskell data type, +-- return the type +-- E.g. given the name "Expr" return the type "Expr" +tcMetaTy tc_name + = tcLookupTyCon tc_name `thenM` \ t -> + returnM (mkGenTyConApp t []) + -- Use mkGenTyConApp because it might be a synonym \end{code} -A @ClsInstEnv@ lives inside a class, and identifies all the instances -of that class. The @Id@ inside a ClsInstEnv mapping is the dfun for -that instance. - -If class C maps to a list containing the item ([a,b], [t1,t2,t3], dfun), then - - forall a b, C t1 t2 t3 can be constructed by dfun - -or, to put it another way, we have - - instance (...) => C t1 t2 t3, witnessed by dfun - -There is an important consistency constraint in the elements of a ClsInstEnv: - - * [a,b] must be a superset of the free vars of [t1,t2,t3] - - * The dfun must itself be quantified over [a,b] - -Thus, the @ClassInstEnv@ for @Eq@ might contain the following entry: - [a] ===> dfun_Eq_List :: forall a. Eq a => Eq [a] -The "a" in the pattern must be one of the forall'd variables in -the dfun type. - - - -Notes on overlapping instances -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ -In some ClsInstEnvs, overlap is prohibited; that is, no pair of templates unify. - -In others, overlap is permitted, but only in such a way that one can make -a unique choice when looking up. That is, overlap is only permitted if -one template matches the other, or vice versa. So this is ok: - - [a] [Int] - -but this is not - - (Int,a) (b,Int) - -If overlap is permitted, the list is kept most specific first, so that -the first lookup is the right choice. - - -For now we just use association lists. - -\subsection{Avoiding a problem with overlapping} - -Consider this little program: - -\begin{pseudocode} - class C a where c :: a - class C a => D a where d :: a - - instance C Int where c = 17 - instance D Int where d = 13 - - instance C a => C [a] where c = [c] - instance ({- C [a], -} D a) => D [a] where d = c - - instance C [Int] where c = [37] - - main = print (d :: [Int]) -\end{pseudocode} -What do you think `main' prints (assuming we have overlapping instances, and -all that turned on)? Well, the instance for `D' at type `[a]' is defined to -be `c' at the same type, and we've got an instance of `C' at `[Int]', so the -answer is `[37]', right? (the generic `C [a]' instance shouldn't apply because -the `C [Int]' instance is more specific). - -Ghc-4.04 gives `[37]', while ghc-4.06 gives `[17]', so 4.06 is wrong. That -was easy ;-) Let's just consult hugs for good measure. Wait - if I use old -hugs (pre-September99), I get `[17]', and stranger yet, if I use hugs98, it -doesn't even compile! What's going on!? - -What hugs complains about is the `D [a]' instance decl. - -\begin{pseudocode} - ERROR "mj.hs" (line 10): Cannot build superclass instance - *** Instance : D [a] - *** Context supplied : D a - *** Required superclass : C [a] -\end{pseudocode} - -You might wonder what hugs is complaining about. It's saying that you -need to add `C [a]' to the context of the `D [a]' instance (as appears -in comments). But there's that `C [a]' instance decl one line above -that says that I can reduce the need for a `C [a]' instance to the -need for a `C a' instance, and in this case, I already have the -necessary `C a' instance (since we have `D a' explicitly in the -context, and `C' is a superclass of `D'). +%************************************************************************ +%* * +\subsection{Making new Ids} +%* * +%************************************************************************ -Unfortunately, the above reasoning indicates a premature commitment to the -generic `C [a]' instance. I.e., it prematurely rules out the more specific -instance `C [Int]'. This is the mistake that ghc-4.06 makes. The fix is to -add the context that hugs suggests (uncomment the `C [a]'), effectively -deferring the decision about which instance to use. +Constructing new Ids -Now, interestingly enough, 4.04 has this same bug, but it's covered up -in this case by a little known `optimization' that was disabled in -4.06. Ghc-4.04 silently inserts any missing superclass context into -an instance declaration. In this case, it silently inserts the `C -[a]', and everything happens to work out. +\begin{code} +newLocalName :: Name -> TcM Name +newLocalName name -- Make a clone + = newUnique `thenM` \ uniq -> + returnM (mkInternalName uniq (getOccName name) (getSrcLoc name)) +\end{code} -(See `basicTypes/MkId:mkDictFunId' for the code in question. Search for -`Mark Jones', although Mark claims no credit for the `optimization' in -question, and would rather it stopped being called the `Mark Jones -optimization' ;-) +Make a name for the dict fun for an instance decl. It's a *local* +name for the moment. The CoreTidy pass will externalise it. Even in +--make and ghci stuff, we rebuild the instance environment each time, +so the dfun id is internal to begin with, and external when compiling +other modules -So, what's the fix? I think hugs has it right. Here's why. Let's try -something else out with ghc-4.04. Let's add the following line: +\begin{code} +newDFunName :: Class -> [Type] -> SrcLoc -> TcM Name +newDFunName clas (ty:_) loc + = newUnique `thenM` \ uniq -> + returnM (mkInternalName uniq (mkDFunOcc dfun_string) loc) + where + -- Any string that is somewhat unique will do + dfun_string = occNameString (getOccName clas) ++ occNameString (getDFunTyKey ty) - d' :: D a => [a] - d' = c +newDFunName clas [] loc = pprPanic "newDFunName" (ppr clas <+> ppr loc) +\end{code} -Everyone raise their hand who thinks that `d :: [Int]' should give a -different answer from `d' :: [Int]'. Well, in ghc-4.04, it does. The -`optimization' only applies to instance decls, not to regular -bindings, giving inconsistent behavior. -Old hugs had this same bug. Here's how we fixed it: like GHC, the -list of instances for a given class is ordered, so that more specific -instances come before more generic ones. For example, the instance -list for C might contain: - ..., C Int, ..., C a, ... -When we go to look for a `C Int' instance we'll get that one first. -But what if we go looking for a `C b' (`b' is unconstrained)? We'll -pass the `C Int' instance, and keep going. But if `b' is -unconstrained, then we don't know yet if the more specific instance -will eventually apply. GHC keeps going, and matches on the generic `C -a'. The fix is to, at each step, check to see if there's a reverse -match, and if so, abort the search. This prevents hugs from -prematurely chosing a generic instance when a more specific one -exists. +%************************************************************************ +%* * +\subsection{The InstInfo type} +%* * +%************************************************************************ ---Jeff +The InstInfo type summarises the information in an instance declaration -\begin{code} -emptyInstEnv :: InstEnv -emptyInstEnv = emptyUFM -\end{code} + instance c => k (t tvs) where b -@lookupInstEnv@ looks up in a @InstEnv@, using a one-way match. Since -the env is kept ordered, the first match must be the only one. The -thing we are looking up can have an arbitrary "flexi" part. +It is used just for *local* instance decls (not ones from interface files). +But local instance decls includes + - derived ones + - generic ones +as well as explicit user written ones. \begin{code} -lookupInstEnv :: InstEnv -- The envt - -> Class -> [Type] -- Key - -> InstLookupResult - -data InstLookupResult - = FoundInst -- There is a (template,substitution) pair - -- that makes the template match the key, - -- and no template is an instance of the key - TyVarSubstEnv Id - - | NoMatch Bool -- Boolean is true iff there is at least one - -- template that matches the key. - -- (but there are other template(s) that are - -- instances of the key, so we don't report - -- FoundInst) - -- The NoMatch True case happens when we look up - -- Foo [a] - -- in an InstEnv that has entries for - -- Foo [Int] - -- Foo [b] - -- Then which we choose would depend on the way in which 'a' - -- is instantiated. So we say there is no match, but identify - -- it as ambiguous case in the hope of giving a better error msg. - -- See the notes above from Jeff Lewis - -lookupInstEnv env key_cls key_tys - = find (classInstEnv env key_cls) - where - key_vars = tyVarsOfTypes key_tys - - find [] = NoMatch False - find ((tpl_tyvars, tpl, val) : rest) - = case matchTys tpl_tyvars tpl key_tys of - Nothing -> - case matchTys key_vars key_tys tpl of - Nothing -> find rest - Just (_, _) -> NoMatch (any_match rest) - Just (subst, leftovers) -> ASSERT( null leftovers ) - FoundInst subst val - - any_match rest = or [ maybeToBool (matchTys tvs tpl key_tys) - | (tvs,tpl,_) <- rest - ] -\end{code} +data InstInfo + = InstInfo { + iDFunId :: DFunId, -- The dfun id + iBinds :: InstBindings + } -@addToClsInstEnv@ extends a @ClsInstEnv@, checking for overlaps. +data InstBindings + = VanillaInst -- The normal case + (LHsBinds Name) -- Bindings + [LSig Name] -- User pragmas recorded for generating + -- specialised instances -A boolean flag controls overlap reporting. + | NewTypeDerived -- Used for deriving instances of newtypes, where the + [Type] -- witness dictionary is identical to the argument + -- dictionary. Hence no bindings, no pragmas + -- The [Type] are the representation types + -- See notes in TcDeriv -True => overlap is permitted, but only if one template matches the other; - not if they unify but neither is +pprInstInfo info = vcat [ptext SLIT("InstInfo:") <+> ppr (idType (iDFunId info))] -\begin{code} -addToInstEnv :: Bool -- True <=> overlap permitted - -> InstEnv -- Envt - -> Class -> [TyVar] -> [Type] -> Id -- New item - -> MaybeErr InstEnv -- Success... - ([Type], Id) -- Failure: Offending overlap - -addToInstEnv overlap_ok inst_env clas ins_tvs ins_tys value - = case insert_into (classInstEnv inst_env clas) of - Failed stuff -> Failed stuff - Succeeded new_env -> Succeeded (addToUFM inst_env clas new_env) - +pprInstInfoDetails info = pprInstInfo info $$ nest 2 (details (iBinds info)) where - ins_tv_set = mkVarSet ins_tvs - ins_item = (ins_tv_set, ins_tys, value) - - insert_into [] = returnMaB [ins_item] - insert_into env@(cur_item@(tpl_tvs, tpl_tys, val) : rest) - - -- FAIL if: - -- (a) they are the same, or - -- (b) they unify, and any sort of overlap is prohibited, - -- (c) they unify but neither is more specific than t'other - | identical - || (unifiable && not overlap_ok) - || (unifiable && not (ins_item_more_specific || cur_item_more_specific)) - = failMaB (tpl_tys, val) - - -- New item is an instance of current item, so drop it here - | ins_item_more_specific = returnMaB (ins_item : env) - - -- Otherwise carry on - | otherwise = insert_into rest `thenMaB` \ rest' -> - returnMaB (cur_item : rest') - where - unifiable = maybeToBool (unifyTyListsX (ins_tv_set `unionVarSet` tpl_tvs) tpl_tys ins_tys) - ins_item_more_specific = maybeToBool (matchTys tpl_tvs tpl_tys ins_tys) - cur_item_more_specific = maybeToBool (matchTys ins_tv_set ins_tys tpl_tys) - identical = ins_item_more_specific && cur_item_more_specific -\end{code} - -Make a name for the dict fun for an instance decl + details (VanillaInst b _) = ppr b + details (NewTypeDerived _) = text "Derived from the representation type" -\begin{code} -newDFunName :: Module -> Class -> [Type] -> SrcLoc -> NF_TcM s Name -newDFunName mod clas (ty:_) loc - = tcGetDFunUniq dfun_string `thenNF_Tc` \ inst_uniq -> - tcGetUnique `thenNF_Tc` \ uniq -> - returnNF_Tc (mkGlobalName uniq mod - (mkDFunOcc dfun_string inst_uniq) - (LocalDef loc Exported)) - where - -- Any string that is somewhat unique will do - dfun_string = occNameString (getOccName clas) ++ occNameString (getDFunTyKey ty) +simpleInstInfoTy :: InstInfo -> Type +simpleInstInfoTy info = case tcSplitDFunTy (idType (iDFunId info)) of + (_, _, _, [ty]) -> ty -newDefaultMethodName :: Name -> SrcLoc -> NF_TcM s Name -newDefaultMethodName op_name loc - = tcGetUnique `thenNF_Tc` \ uniq -> - returnNF_Tc (mkGlobalName uniq (nameModule op_name) - (mkDefaultMethodOcc (getOccName op_name)) - (LocalDef loc Exported)) +simpleInstInfoTyCon :: InstInfo -> TyCon + -- Gets the type constructor for a simple instance declaration, + -- i.e. one of the form instance (...) => C (T a b c) where ... +simpleInstInfoTyCon inst = tcTyConAppTyCon (simpleInstInfoTy inst) \end{code} @@ -771,14 +622,17 @@ newDefaultMethodName op_name loc %************************************************************************ \begin{code} -badCon con_id - = quotes (ppr con_id) <+> ptext SLIT("is not a data constructor") -badPrimOp op - = quotes (ppr op) <+> ptext SLIT("is not a primop") +notFound wheRe name = failWithTc (text wheRe <> colon <+> quotes (ppr name) <+> + ptext SLIT("is not in scope")) -uvNameOutOfScope name - = ptext SLIT("UVar") <+> quotes (ppr name) <+> ptext SLIT("is not in scope") - -tyNameOutOfScope name - = quotes (ppr name) <+> ptext SLIT("is not in scope") +wrongThingErr expected thing name + = failWithTc (pp_thing thing <+> quotes (ppr name) <+> + ptext SLIT("used as a") <+> text expected) + where + pp_thing (AGlobal (ATyCon _)) = ptext SLIT("Type constructor") + pp_thing (AGlobal (AClass _)) = ptext SLIT("Class") + pp_thing (AGlobal (AnId _)) = ptext SLIT("Identifier") + pp_thing (AGlobal (ADataCon _)) = ptext SLIT("Data constructor") + pp_thing (ATyVar _) = ptext SLIT("Type variable") + pp_thing (ATcId _ _ _) = ptext SLIT("Local identifier") \end{code}