%
-% (c) The GRASP/AQUA Project, Glasgow University, 1992-1996
+% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
%
\section[Inst]{The @Inst@ type: dictionaries or method instances}
\begin{code}
-module Inst (
- LIE, emptyLIE, unitLIE, plusLIE, consLIE, zonkLIE, plusLIEs, mkLIE,
- pprInsts, pprInstsInFull,
+module Inst (
+ LIE, emptyLIE, unitLIE, plusLIE, consLIE, zonkLIE,
+ plusLIEs, mkLIE, isEmptyLIE, lieToList, listToLIE,
- Inst, OverloadedLit(..), pprInst,
+ Inst,
+ pprInst, pprInsts, pprInstsInFull, tidyInst, tidyInsts,
- InstanceMapper,
-
- newDictFromOld, newDicts, newDictsAtLoc,
+ newDictsFromOld, newDicts, newClassDicts,
newMethod, newMethodWithGivenTy, newOverloadedLit,
+ newIPDict, tcInstId,
- tyVarsOfInst, instLoc, getDictClassTys,
+ tyVarsOfInst, tyVarsOfInsts, tyVarsOfLIE, instLoc, getDictClassTys,
+ getIPs,
+ predsOfInsts,
lookupInst, lookupSimpleInst, LookupInstResult(..),
- isDict, isTyVarDict, isStdClassTyVarDict, isMethodFor,
+ isDict, isClassDict, isMethod, instMentionsIPs,
+ isTyVarDict, isStdClassTyVarDict, isMethodFor,
instBindingRequired, instCanBeGeneralised,
- zonkInst, instToId,
+ zonkInst, zonkInsts,
+ instToId,
- InstOrigin(..), pprOrigin
+ InstOrigin(..), InstLoc, pprInstLoc
) where
#include "HsVersions.h"
-import HsSyn ( HsLit(..), HsExpr(..), MonoBinds )
-import RnHsSyn ( RenamedArithSeqInfo, RenamedHsExpr )
-import TcHsSyn ( TcExpr, TcIdOcc(..), TcIdBndr,
- mkHsTyApp, mkHsDictApp, tcIdTyVars, zonkTcId
+import CmdLineOpts ( opt_NoMethodSharing )
+import HsSyn ( HsLit(..), HsOverLit(..), HsExpr(..) )
+import TcHsSyn ( TcExpr, TcId,
+ mkHsTyApp, mkHsDictApp, mkHsConApp, zonkId
)
import TcMonad
-import TcEnv ( tcLookupGlobalValueByKey, tcLookupTyConByKey )
-import TcType ( TcThetaType,
- TcType, TcTauType, TcMaybe, TcTyVarSet,
- tcInstType, zonkTcType, zonkTcTypes, tcSplitForAllTy,
- zonkTcThetaType
- )
-import Bag ( emptyBag, unitBag, unionBags, unionManyBags,
- listToBag, consBag, Bag )
-import Class ( classInstEnv,
- Class, ClassInstEnv
- )
-import Id ( idType, mkUserLocal, mkSysLocal, Id,
- GenIdSet, elementOfIdSet
+import TcEnv ( TcIdSet, tcGetInstEnv, tcLookupSyntaxId )
+import InstEnv ( InstLookupResult(..), lookupInstEnv )
+import TcType ( TcThetaType, TcClassContext,
+ TcType, TcTauType, TcTyVarSet,
+ zonkTcType, zonkTcTypes,
+ zonkTcThetaType, tcInstTyVar, tcInstType
)
+import CoreFVs ( idFreeTyVars )
+import Class ( Class )
+import Id ( Id, idType, mkUserLocal, mkSysLocal, mkLocalId )
import PrelInfo ( isStandardClass, isCcallishClass, isNoDictClass )
-import Name ( OccName(..), Name, occNameString, getOccName )
-import PprType ( TyCon, pprConstraint )
-import SpecEnv ( SpecEnv, matchSpecEnv, addToSpecEnv )
-import SrcLoc ( SrcLoc )
-import Type ( Type, ThetaType, instantiateTy, instantiateThetaTy, matchTys,
- isTyVarTy, mkDictTy, splitForAllTys, splitSigmaTy,
- splitRhoTy, tyVarsOfType, tyVarsOfTypes,
- mkSynTy
+import Name ( mkDictOcc, mkMethodOcc, getOccName, mkLocalName )
+import NameSet ( NameSet )
+import PprType ( pprPred )
+import Type ( Type, PredType(..),
+ isTyVarTy, mkPredTy, mkTyVarTy, mkTyVarTys,
+ splitForAllTys, splitSigmaTy, funArgTy,
+ splitMethodTy, splitRhoTy, classesOfPreds,
+ tyVarsOfType, tyVarsOfTypes, tyVarsOfPred,
+ tidyOpenType, tidyOpenTypes, predMentionsIPs
)
-import TyVar ( zipTyVarEnv, lookupTyVarEnv, unionTyVarSets )
-import TysPrim ( intPrimTy )
-import TysWiredIn ( intDataCon, integerTy, isIntTy, isIntegerTy, inIntRange )
-import Unique ( fromRationalClassOpKey, rationalTyConKey,
- fromIntClassOpKey, fromIntegerClassOpKey, Unique
+import Subst ( emptyInScopeSet, mkSubst,
+ substTy, substClasses, mkTyVarSubst, mkTopTyVarSubst
)
-import Maybes ( MaybeErr, expectJust )
-import Util ( thenCmp, zipWithEqual )
+import Literal ( inIntRange )
+import VarEnv ( TidyEnv, lookupSubstEnv, SubstResult(..) )
+import VarSet ( elemVarSet, emptyVarSet, unionVarSet )
+import TysWiredIn ( isIntTy,
+ floatDataCon, isFloatTy,
+ doubleDataCon, isDoubleTy,
+ isIntegerTy
+ )
+import PrelNames( fromIntegerName, fromRationalName )
+import Util ( thenCmp, zipWithEqual, mapAccumL )
+import Bag
import Outputable
\end{code}
%************************************************************************
\begin{code}
-type LIE s = Bag (Inst s)
+type LIE = Bag Inst
+isEmptyLIE = isEmptyBag
emptyLIE = emptyBag
unitLIE inst = unitBag inst
mkLIE insts = listToBag insts
plusLIE lie1 lie2 = lie1 `unionBags` lie2
consLIE inst lie = inst `consBag` lie
plusLIEs lies = unionManyBags lies
+lieToList = bagToList
+listToLIE = listToBag
-zonkLIE :: LIE s -> NF_TcM s (LIE s)
+zonkLIE :: LIE -> NF_TcM LIE
zonkLIE lie = mapBagNF_Tc zonkInst lie
-pprInsts :: [Inst s] -> SDoc
-pprInsts insts = parens (hsep (punctuate comma (map pprInst insts)))
+pprInsts :: [Inst] -> SDoc
+pprInsts insts = parens (sep (punctuate comma (map pprInst insts)))
pprInstsInFull insts
= vcat (map go insts)
where
- go inst = quotes (ppr inst) <+> pprOrigin inst
+ go inst = quotes (ppr inst) <+> pprInstLoc (instLoc inst)
\end{code}
%************************************************************************
Method 34 doubleId [Int] origin
\begin{code}
-data Inst s
+data Inst
= Dict
- Unique
- Class -- The type of the dict is (c ts), where
- [TcType s] -- c is the class and ts the types;
- (InstOrigin s)
- SrcLoc
+ Id
+ TcPredType
+ InstLoc
| Method
- Unique
+ Id
- (TcIdOcc s) -- The overloaded function
+ TcId -- The overloaded function
-- This function will be a global, local, or ClassOpId;
-- inside instance decls (only) it can also be an InstId!
-- The id needn't be completely polymorphic.
-- You'll probably find its name (for documentation purposes)
-- inside the InstOrigin
- [TcType s] -- The types to which its polymorphic tyvars
+ [TcType] -- The types to which its polymorphic tyvars
-- should be instantiated.
-- These types must saturate the Id's foralls.
- (TcThetaType s) -- The (types of the) dictionaries to which the function
+ TcThetaType -- The (types of the) dictionaries to which the function
-- must be applied to get the method
- (TcTauType s) -- The type of the method
+ TcTauType -- The type of the method
- (InstOrigin s)
- SrcLoc
+ InstLoc
-- INVARIANT: in (Method u f tys theta tau loc)
-- type of (f tys dicts(from theta)) = tau
| LitInst
- Unique
- OverloadedLit
- (TcType s) -- The type at which the literal is used
- (InstOrigin s) -- Always a literal; but more convenient to carry this around
- SrcLoc
-
-data OverloadedLit
- = OverloadedIntegral Integer -- The number
- | OverloadedFractional Rational -- The number
+ Id
+ HsOverLit -- The literal from the occurrence site
+ TcType -- The type at which the literal is used
+ InstLoc
\end{code}
Ordering
maps to do their stuff.
\begin{code}
-instance Ord (Inst s) where
+instance Ord Inst where
compare = cmpInst
-instance Eq (Inst s) where
+instance Eq Inst where
(==) i1 i2 = case i1 `cmpInst` i2 of
EQ -> True
other -> False
-cmpInst (Dict _ clas1 tys1 _ _) (Dict _ clas2 tys2 _ _)
- = (clas1 `compare` clas2) `thenCmp` (tys1 `compare` tys2)
-cmpInst (Dict _ _ _ _ _) other
- = LT
-
+cmpInst (Dict _ pred1 _) (Dict _ pred2 _) = (pred1 `compare` pred2)
+cmpInst (Dict _ _ _) other = LT
-cmpInst (Method _ _ _ _ _ _ _) (Dict _ _ _ _ _)
- = GT
-cmpInst (Method _ id1 tys1 _ _ _ _) (Method _ id2 tys2 _ _ _ _)
- = (id1 `compare` id2) `thenCmp` (tys1 `compare` tys2)
-cmpInst (Method _ _ _ _ _ _ _) other
- = LT
+cmpInst (Method _ _ _ _ _ _) (Dict _ _ _) = GT
+cmpInst (Method _ id1 tys1 _ _ _) (Method _ id2 tys2 _ _ _) = (id1 `compare` id2) `thenCmp` (tys1 `compare` tys2)
+cmpInst (Method _ _ _ _ _ _) other = LT
-cmpInst (LitInst _ lit1 ty1 _ _) (LitInst _ lit2 ty2 _ _)
- = (lit1 `cmpOverLit` lit2) `thenCmp` (ty1 `compare` ty2)
-cmpInst (LitInst _ _ _ _ _) other
- = GT
+cmpInst (LitInst _ lit1 ty1 _) (LitInst _ lit2 ty2 _) = (lit1 `compare` lit2) `thenCmp` (ty1 `compare` ty2)
+cmpInst (LitInst _ _ _ _) other = GT
-cmpOverLit (OverloadedIntegral i1) (OverloadedIntegral i2) = i1 `compare` i2
-cmpOverLit (OverloadedFractional f1) (OverloadedFractional f2) = f1 `compare` f2
-cmpOverLit (OverloadedIntegral _) (OverloadedFractional _) = LT
-cmpOverLit (OverloadedFractional _) (OverloadedIntegral _) = GT
+-- and they can only have HsInt or HsFracs in them.
\end{code}
Selection
~~~~~~~~~
\begin{code}
-instOrigin (Dict u clas tys origin loc) = origin
-instOrigin (Method u clas ty _ _ origin loc) = origin
-instOrigin (LitInst u lit ty origin loc) = origin
+instToId :: Inst -> TcId
+instToId (Dict id _ _) = id
+instToId (Method id _ _ _ _ _) = id
+instToId (LitInst id _ _ _) = id
+
+instLoc (Dict _ _ loc) = loc
+instLoc (Method _ _ _ _ _ loc) = loc
+instLoc (LitInst _ _ _ loc) = loc
+
+getDictClassTys (Dict _ (Class clas tys) _) = (clas, tys)
+
+predsOfInsts :: [Inst] -> [PredType]
+predsOfInsts insts = concatMap predsOfInst insts
+
+predsOfInst (Dict _ pred _) = [pred]
+predsOfInst (Method _ _ _ theta _ _) = theta
+predsOfInst (LitInst _ _ _ _) = []
+ -- The last case is is really a big cheat
+ -- LitInsts to give rise to a (Num a) or (Fractional a) predicate
+ -- But Num and Fractional have only one parameter and no functional
+ -- dependencies, so I think no caller of predsOfInst will care.
-instLoc (Dict u clas tys origin loc) = loc
-instLoc (Method u clas ty _ _ origin loc) = loc
-instLoc (LitInst u lit ty origin loc) = loc
+ipsOfPreds theta = [(n,ty) | IParam n ty <- theta]
-getDictClassTys (Dict u clas tys _ _) = (clas, tys)
+getIPs inst = ipsOfPreds (predsOfInst inst)
-tyVarsOfInst :: Inst s -> TcTyVarSet s
-tyVarsOfInst (Dict _ _ tys _ _) = tyVarsOfTypes tys
-tyVarsOfInst (Method _ id tys _ _ _ _) = tyVarsOfTypes tys `unionTyVarSets` tcIdTyVars id
- -- The id might not be a RealId; in the case of
+tyVarsOfInst :: Inst -> TcTyVarSet
+tyVarsOfInst (LitInst _ _ ty _) = tyVarsOfType ty
+tyVarsOfInst (Dict _ pred _) = tyVarsOfPred pred
+tyVarsOfInst (Method _ id tys _ _ _) = tyVarsOfTypes tys `unionVarSet` idFreeTyVars id
+ -- The id might have free type variables; in the case of
-- locally-overloaded class methods, for example
-tyVarsOfInst (LitInst _ _ ty _ _) = tyVarsOfType ty
+
+tyVarsOfInsts insts = foldr (unionVarSet . tyVarsOfInst) emptyVarSet insts
+tyVarsOfLIE lie = tyVarsOfInsts (lieToList lie)
\end{code}
Predicates
~~~~~~~~~~
\begin{code}
-isDict :: Inst s -> Bool
-isDict (Dict _ _ _ _ _) = True
-isDict other = False
-
-isMethodFor :: GenIdSet (TcType s) -> Inst s -> Bool
-isMethodFor ids (Method uniq (TcId id) tys _ _ orig loc)
- = id `elementOfIdSet` ids
-isMethodFor ids inst
+isDict :: Inst -> Bool
+isDict (Dict _ _ _) = True
+isDict other = False
+
+isClassDict :: Inst -> Bool
+isClassDict (Dict _ (Class _ _) _) = True
+isClassDict other = False
+
+isMethod :: Inst -> Bool
+isMethod (Method _ _ _ _ _ _) = True
+isMethod other = False
+
+isMethodFor :: TcIdSet -> Inst -> Bool
+isMethodFor ids (Method uniq id tys _ _ loc) = id `elemVarSet` ids
+isMethodFor ids inst = False
+
+instMentionsIPs :: Inst -> NameSet -> Bool
+ -- True if the Inst mentions any of the implicit
+ -- parameters in the supplied set of names
+instMentionsIPs (Dict _ pred _) ip_names = pred `predMentionsIPs` ip_names
+instMentionsIPs (Method _ _ _ theta _ _) ip_names = any (`predMentionsIPs` ip_names) theta
+instMentionsIPs other ip_names = False
+
+isTyVarDict :: Inst -> Bool
+isTyVarDict (Dict _ (Class _ tys) _) = all isTyVarTy tys
+isTyVarDict other = False
+
+isStdClassTyVarDict (Dict _ (Class clas [ty]) _)
+ = isStandardClass clas && isTyVarTy ty
+isStdClassTyVarDict other
= False
-
-isTyVarDict :: Inst s -> Bool
-isTyVarDict (Dict _ _ tys _ _) = all isTyVarTy tys
-isTyVarDict other = False
-
-isStdClassTyVarDict (Dict _ clas [ty] _ _) = isStandardClass clas && isTyVarTy ty
-isStdClassTyVarDict other = False
\end{code}
Two predicates which deal with the case where class constraints don't
@Inst@ can be generalised over.
\begin{code}
-instBindingRequired :: Inst s -> Bool
-instBindingRequired (Dict _ clas _ _ _) = not (isNoDictClass clas)
-instBindingRequired other = True
-
-instCanBeGeneralised :: Inst s -> Bool
-instCanBeGeneralised (Dict _ clas _ _ _) = not (isCcallishClass clas)
-instCanBeGeneralised other = True
+instBindingRequired :: Inst -> Bool
+instBindingRequired (Dict _ (Class clas _) _) = not (isNoDictClass clas)
+instBindingRequired (Dict _ (IParam _ _) _) = False
+instBindingRequired other = True
+
+instCanBeGeneralised :: Inst -> Bool
+instCanBeGeneralised (Dict _ (Class clas _) _) = not (isCcallishClass clas)
+instCanBeGeneralised other = True
\end{code}
-Construction
-~~~~~~~~~~~~
+%************************************************************************
+%* *
+\subsection{Building dictionaries}
+%* *
+%************************************************************************
\begin{code}
-newDicts :: InstOrigin s
- -> TcThetaType s
- -> NF_TcM s (LIE s, [TcIdOcc s])
+newDicts :: InstOrigin
+ -> TcThetaType
+ -> NF_TcM [Inst]
newDicts orig theta
- = tcGetSrcLoc `thenNF_Tc` \ loc ->
- newDictsAtLoc orig loc theta `thenNF_Tc` \ (dicts, ids) ->
- returnNF_Tc (listToBag dicts, ids)
+ = tcGetInstLoc orig `thenNF_Tc` \ loc ->
+ newDictsAtLoc loc theta
+
+newClassDicts :: InstOrigin
+ -> TcClassContext
+ -> NF_TcM [Inst]
+newClassDicts orig theta = newDicts orig (map (uncurry Class) theta)
+
+newDictsFromOld :: Inst -> TcClassContext -> NF_TcM [Inst]
+newDictsFromOld (Dict _ _ loc) theta = newDictsAtLoc loc (map (uncurry Class) theta)
-- Local function, similar to newDicts,
-- but with slightly different interface
-newDictsAtLoc :: InstOrigin s
- -> SrcLoc
- -> TcThetaType s
- -> NF_TcM s ([Inst s], [TcIdOcc s])
-newDictsAtLoc orig loc theta =
- tcGetUniques (length theta) `thenNF_Tc` \ new_uniqs ->
- let
- mk_dict u (clas, tys) = Dict u clas tys orig loc
- dicts = zipWithEqual "newDictsAtLoc" mk_dict new_uniqs theta
- in
- returnNF_Tc (dicts, map instToId dicts)
-
-newDictFromOld :: Inst s -> Class -> [TcType s] -> NF_TcM s (Inst s)
-newDictFromOld (Dict _ _ _ orig loc) clas tys
- = tcGetUnique `thenNF_Tc` \ uniq ->
- returnNF_Tc (Dict uniq clas tys orig loc)
-
-
-newMethod :: InstOrigin s
- -> TcIdOcc s
- -> [TcType s]
- -> NF_TcM s (LIE s, TcIdOcc s)
+newDictsAtLoc :: InstLoc
+ -> TcThetaType
+ -> NF_TcM [Inst]
+newDictsAtLoc inst_loc@(_,loc,_) theta
+ = tcGetUniques (length theta) `thenNF_Tc` \ new_uniqs ->
+ returnNF_Tc (zipWithEqual "newDictsAtLoc" mk_dict new_uniqs theta)
+ where
+ mk_dict uniq pred = Dict (mkLocalId (mk_dict_name uniq pred) (mkPredTy pred)) pred inst_loc
+
+ mk_dict_name uniq (Class cls tys) = mkLocalName uniq (mkDictOcc (getOccName cls)) loc
+ mk_dict_name uniq (IParam name ty) = name
+
+newIPDict orig name ty
+ = tcGetInstLoc orig `thenNF_Tc` \ inst_loc ->
+ returnNF_Tc (Dict (mkLocalId name ty) (IParam name ty) inst_loc)
+\end{code}
+
+
+%************************************************************************
+%* *
+\subsection{Building methods (calls of overloaded functions)}
+%* *
+%************************************************************************
+
+tcInstId instantiates an occurrence of an Id.
+The instantiate_it loop runs round instantiating the Id.
+It has to be a loop because we are now prepared to entertain
+types like
+ f:: forall a. Eq a => forall b. Baz b => tau
+We want to instantiate this to
+ f2::tau {f2 = f1 b (Baz b), f1 = f a (Eq a)}
+
+The -fno-method-sharing flag controls what happens so far as the LIE
+is concerned. The default case is that for an overloaded function we
+generate a "method" Id, and add the Method Inst to the LIE. So you get
+something like
+ f :: Num a => a -> a
+ f = /\a (d:Num a) -> let m = (+) a d in \ (x:a) -> m x x
+If you specify -fno-method-sharing, the dictionary application
+isn't shared, so we get
+ f :: Num a => a -> a
+ f = /\a (d:Num a) (x:a) -> (+) a d x x
+This gets a bit less sharing, but
+ a) it's better for RULEs involving overloaded functions
+ b) perhaps fewer separated lambdas
+
+
+\begin{code}
+tcInstId :: Id -> NF_TcM (TcExpr, LIE, TcType)
+tcInstId fun
+ | opt_NoMethodSharing = loop_noshare (HsVar fun) (idType fun)
+ | otherwise = loop_share fun
+ where
+ orig = OccurrenceOf fun
+ loop_noshare fun fun_ty
+ = tcInstType fun_ty `thenNF_Tc` \ (tyvars, theta, tau) ->
+ let
+ ty_app = mkHsTyApp fun (mkTyVarTys tyvars)
+ in
+ if null theta then -- Is it overloaded?
+ returnNF_Tc (ty_app, emptyLIE, tau)
+ else
+ newDicts orig theta `thenNF_Tc` \ dicts ->
+ loop_noshare (mkHsDictApp ty_app (map instToId dicts)) tau `thenNF_Tc` \ (expr, lie, final_tau) ->
+ returnNF_Tc (expr, mkLIE dicts `plusLIE` lie, final_tau)
+
+ loop_share fun
+ = tcInstType (idType fun) `thenNF_Tc` \ (tyvars, theta, tau) ->
+ let
+ arg_tys = mkTyVarTys tyvars
+ in
+ if null theta then -- Is it overloaded?
+ returnNF_Tc (mkHsTyApp (HsVar fun) arg_tys, emptyLIE, tau)
+ else
+ -- Yes, it's overloaded
+ newMethodWithGivenTy orig fun arg_tys theta tau `thenNF_Tc` \ meth ->
+ loop_share (instToId meth) `thenNF_Tc` \ (expr, lie, final_tau) ->
+ returnNF_Tc (expr, unitLIE meth `plusLIE` lie, final_tau)
+
+
+newMethod :: InstOrigin
+ -> TcId
+ -> [TcType]
+ -> NF_TcM Inst
newMethod orig id tys
= -- Get the Id type and instantiate it at the specified types
- (case id of
- RealId id -> let (tyvars, rho) = splitForAllTys (idType id)
- in
- ASSERT( length tyvars == length tys)
- tcInstType (zipTyVarEnv tyvars tys) rho
-
- TcId id -> tcSplitForAllTy (idType id) `thenNF_Tc` \ (tyvars, rho) ->
- returnNF_Tc (instantiateTy (zipTyVarEnv tyvars tys) rho)
- ) `thenNF_Tc` \ rho_ty ->
let
- (theta, tau) = splitRhoTy rho_ty
+ (tyvars, rho) = splitForAllTys (idType id)
+ rho_ty = substTy (mkTyVarSubst tyvars tys) rho
+ (pred, tau) = splitMethodTy rho_ty
in
- -- Our friend does the rest
- newMethodWithGivenTy orig id tys theta tau
-
+ newMethodWithGivenTy orig id tys [pred] tau
newMethodWithGivenTy orig id tys theta tau
- = tcGetSrcLoc `thenNF_Tc` \ loc ->
- tcGetUnique `thenNF_Tc` \ new_uniq ->
+ = tcGetInstLoc orig `thenNF_Tc` \ loc ->
+ newMethodWith loc id tys theta tau
+
+newMethodWith inst_loc@(_,loc,_) id tys theta tau
+ = tcGetUnique `thenNF_Tc` \ new_uniq ->
let
- meth_inst = Method new_uniq id tys theta tau orig loc
+ meth_id = mkUserLocal (mkMethodOcc (getOccName id)) new_uniq tau loc
in
- returnNF_Tc (unitLIE meth_inst, instToId meth_inst)
+ returnNF_Tc (Method meth_id id tys theta tau inst_loc)
-newMethodAtLoc :: InstOrigin s -> SrcLoc
- -> Id -> [TcType s]
- -> NF_TcM s (Inst s, TcIdOcc s)
-newMethodAtLoc orig loc real_id tys -- Local function, similar to newMethod but with
- -- slightly different interface
+newMethodAtLoc :: InstLoc
+ -> Id -> [TcType]
+ -> NF_TcM (Inst, TcId)
+newMethodAtLoc inst_loc real_id tys
+ -- This actually builds the Inst
= -- Get the Id type and instantiate it at the specified types
let
- (tyvars,rho) = splitForAllTys (idType real_id)
- in
- tcInstType (zipTyVarEnv tyvars tys) rho `thenNF_Tc` \ rho_ty ->
- tcGetUnique `thenNF_Tc` \ new_uniq ->
- let
- (theta, tau) = splitRhoTy rho_ty
- meth_inst = Method new_uniq (RealId real_id) tys theta tau orig loc
+ (tyvars,rho) = splitForAllTys (idType real_id)
+ rho_ty = ASSERT( length tyvars == length tys )
+ substTy (mkTopTyVarSubst tyvars tys) rho
+ (theta, tau) = splitRhoTy rho_ty
in
+ newMethodWith inst_loc real_id tys theta tau `thenNF_Tc` \ meth_inst ->
returnNF_Tc (meth_inst, instToId meth_inst)
+\end{code}
-newOverloadedLit :: InstOrigin s
- -> OverloadedLit
- -> TcType s
- -> NF_TcM s (TcExpr s, LIE s)
-newOverloadedLit orig (OverloadedIntegral i) ty
+In newOverloadedLit we convert directly to an Int or Integer if we
+know that's what we want. This may save some time, by not
+temporarily generating overloaded literals, but it won't catch all
+cases (the rest are caught in lookupInst).
+
+\begin{code}
+newOverloadedLit :: InstOrigin
+ -> HsOverLit
+ -> TcType
+ -> NF_TcM (TcExpr, LIE)
+newOverloadedLit orig (HsIntegral i) ty
| isIntTy ty && inIntRange i -- Short cut for Int
= returnNF_Tc (int_lit, emptyLIE)
= returnNF_Tc (integer_lit, emptyLIE)
where
- intprim_lit = HsLitOut (HsIntPrim i) intPrimTy
- integer_lit = HsLitOut (HsInt i) integerTy
- int_lit = HsApp (HsVar (RealId intDataCon)) intprim_lit
+ int_lit = HsLit (HsInt i)
+ integer_lit = HsLit (HsInteger i)
newOverloadedLit orig lit ty -- The general case
- = tcGetSrcLoc `thenNF_Tc` \ loc ->
+ = tcGetInstLoc orig `thenNF_Tc` \ loc ->
tcGetUnique `thenNF_Tc` \ new_uniq ->
let
- lit_inst = LitInst new_uniq lit ty orig loc
+ lit_inst = LitInst lit_id lit ty loc
+ lit_id = mkSysLocal SLIT("lit") new_uniq ty
in
returnNF_Tc (HsVar (instToId lit_inst), unitLIE lit_inst)
\end{code}
-\begin{code}
-instToId :: Inst s -> TcIdOcc s
-instToId (Dict u clas ty orig loc)
- = TcId (mkUserLocal occ u (mkDictTy clas ty) loc)
- where
- occ = VarOcc (SLIT("d.") _APPEND_ (occNameString (getOccName clas)))
-
-instToId (Method u id tys theta tau orig loc)
- = TcId (mkUserLocal (getOccName id) u tau loc)
-
-instToId (LitInst u list ty orig loc)
- = TcId (mkSysLocal SLIT("lit") u ty loc)
-\end{code}
-
+%************************************************************************
+%* *
+\subsection{Zonking}
+%* *
+%************************************************************************
-Zonking
-~~~~~~~
Zonking makes sure that the instance types are fully zonked,
-but doesn't do the same for the Id in a Method. There's no
+but doesn't do the same for any of the Ids in an Inst. There's no
need, and it's a lot of extra work.
\begin{code}
-zonkInst :: Inst s -> NF_TcM s (Inst s)
-zonkInst (Dict u clas tys orig loc)
- = zonkTcTypes tys `thenNF_Tc` \ new_tys ->
- returnNF_Tc (Dict u clas new_tys orig loc)
-
-zonkInst (Method u id tys theta tau orig loc)
- = zonkTcId id `thenNF_Tc` \ new_id ->
- -- Essential to zonk the id in case it's a local variable
+zonkPred :: TcPredType -> NF_TcM TcPredType
+zonkPred (Class clas tys)
+ = zonkTcTypes tys `thenNF_Tc` \ new_tys ->
+ returnNF_Tc (Class clas new_tys)
+zonkPred (IParam n ty)
+ = zonkTcType ty `thenNF_Tc` \ new_ty ->
+ returnNF_Tc (IParam n new_ty)
+
+zonkInst :: Inst -> NF_TcM Inst
+zonkInst (Dict id pred loc)
+ = zonkPred pred `thenNF_Tc` \ new_pred ->
+ returnNF_Tc (Dict id new_pred loc)
+
+zonkInst (Method m id tys theta tau loc)
+ = zonkId id `thenNF_Tc` \ new_id ->
+ -- Essential to zonk the id in case it's a local variable
+ -- Can't use zonkIdOcc because the id might itself be
+ -- an InstId, in which case it won't be in scope
+
zonkTcTypes tys `thenNF_Tc` \ new_tys ->
zonkTcThetaType theta `thenNF_Tc` \ new_theta ->
zonkTcType tau `thenNF_Tc` \ new_tau ->
- returnNF_Tc (Method u new_id new_tys new_theta new_tau orig loc)
+ returnNF_Tc (Method m new_id new_tys new_theta new_tau loc)
-zonkInst (LitInst u lit ty orig loc)
+zonkInst (LitInst id lit ty loc)
= zonkTcType ty `thenNF_Tc` \ new_ty ->
- returnNF_Tc (LitInst u lit new_ty orig loc)
+ returnNF_Tc (LitInst id lit new_ty loc)
+
+zonkInsts insts = mapNF_Tc zonkInst insts
\end{code}
-Printing
-~~~~~~~~
+%************************************************************************
+%* *
+\subsection{Printing}
+%* *
+%************************************************************************
+
ToDo: improve these pretty-printing things. The ``origin'' is really only
relevant in error messages.
\begin{code}
-instance Outputable (Inst s) where
+instance Outputable Inst where
ppr inst = pprInst inst
-pprInst (LitInst u lit ty orig loc)
- = hsep [case lit of
- OverloadedIntegral i -> integer i
- OverloadedFractional f -> rational f,
- ptext SLIT("at"),
- ppr ty,
- show_uniq u]
+pprInst (LitInst u lit ty loc)
+ = hsep [ppr lit, ptext SLIT("at"), ppr ty, show_uniq u]
-pprInst (Dict u clas tys orig loc) = pprConstraint clas tys <+> show_uniq u
+pprInst (Dict u pred loc) = pprPred pred <+> show_uniq u
-pprInst (Method u id tys _ _ orig loc)
+pprInst m@(Method u id tys theta tau loc)
= hsep [ppr id, ptext SLIT("at"),
- interppSP tys,
- show_uniq u]
+ brackets (interppSP tys) {- ,
+ ptext SLIT("theta"), ppr theta,
+ ptext SLIT("tau"), ppr tau
+ show_uniq u,
+ ppr (instToId m) -}]
+
+tidyPred :: TidyEnv -> TcPredType -> (TidyEnv, TcPredType)
+tidyPred env (Class clas tys)
+ = (env', Class clas tys')
+ where
+ (env', tys') = tidyOpenTypes env tys
+tidyPred env (IParam n ty)
+ = (env', IParam n ty')
+ where
+ (env', ty') = tidyOpenType env ty
+
+tidyInst :: TidyEnv -> Inst -> (TidyEnv, Inst)
+tidyInst env (LitInst u lit ty loc)
+ = (env', LitInst u lit ty' loc)
+ where
+ (env', ty') = tidyOpenType env ty
+
+tidyInst env (Dict u pred loc)
+ = (env', Dict u pred' loc)
+ where
+ (env', pred') = tidyPred env pred
+
+tidyInst env (Method u id tys theta tau loc)
+ = (env', Method u id tys' theta tau loc)
+ -- Leave theta, tau alone cos we don't print them
+ where
+ (env', tys') = tidyOpenTypes env tys
+
+tidyInsts env insts = mapAccumL tidyInst env insts
show_uniq u = ifPprDebug (text "{-" <> ppr u <> text "-}")
\end{code}
%************************************************************************
%* *
-\subsection[InstEnv-types]{Type declarations}
+\subsection{Looking up Insts}
%* *
%************************************************************************
\begin{code}
-type InstanceMapper = Class -> ClassInstEnv
-\end{code}
-
-A @ClassInstEnv@ lives inside a class, and identifies all the instances
-of that class. The @Id@ inside a ClassInstEnv mapping is the dfun for
-that instance.
-
-There is an important consistency constraint between the @MatchEnv@s
-in and the dfun @Id@s inside them: the free type variables of the
-@Type@ key in the @MatchEnv@ must be a subset of the universally-quantified
-type variables of the dfun. 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.
-
-\begin{code}
data LookupInstResult s
= NoInstance
- | SimpleInst (TcExpr s) -- Just a variable, type application, or literal
- | GenInst [Inst s] (TcExpr s) -- The expression and its needed insts
-lookupInst :: Inst s
- -> NF_TcM s (LookupInstResult s)
+ | SimpleInst TcExpr -- Just a variable, type application, or literal
+ | GenInst [Inst] TcExpr -- The expression and its needed insts
+
+lookupInst :: Inst
+ -> NF_TcM (LookupInstResult s)
-- Dictionaries
-lookupInst dict@(Dict _ clas tys orig loc)
- = case matchSpecEnv (classInstEnv clas) tys of
+lookupInst dict@(Dict _ (Class clas tys) loc)
+ = tcGetInstEnv `thenNF_Tc` \ inst_env ->
+ case lookupInstEnv inst_env clas tys of
- Just (tenv, dfun_id)
+ FoundInst tenv dfun_id
-> let
(tyvars, rho) = splitForAllTys (idType dfun_id)
- ty_args = map (expectJust "Inst" . lookupTyVarEnv tenv) tyvars
- -- tenv should bind all the tyvars
+ mk_ty_arg tv = case lookupSubstEnv tenv tv of
+ Just (DoneTy ty) -> returnNF_Tc ty
+ Nothing -> tcInstTyVar tv `thenNF_Tc` \ tc_tv ->
+ returnTc (mkTyVarTy tc_tv)
in
- tcInstType tenv rho `thenNF_Tc` \ dfun_rho ->
+ mapNF_Tc mk_ty_arg tyvars `thenNF_Tc` \ ty_args ->
let
- (theta, tau) = splitRhoTy dfun_rho
- ty_app = mkHsTyApp (HsVar (RealId dfun_id)) ty_args
+ subst = mkTyVarSubst tyvars ty_args
+ dfun_rho = substTy subst rho
+ (theta, _) = splitRhoTy dfun_rho
+ ty_app = mkHsTyApp (HsVar dfun_id) ty_args
in
if null theta then
returnNF_Tc (SimpleInst ty_app)
else
- newDictsAtLoc orig loc theta `thenNF_Tc` \ (dicts, dict_ids) ->
+ newDictsAtLoc loc theta `thenNF_Tc` \ dicts ->
let
- rhs = mkHsDictApp ty_app dict_ids
+ rhs = mkHsDictApp ty_app (map instToId dicts)
in
returnNF_Tc (GenInst dicts rhs)
-
- Nothing -> returnNF_Tc NoInstance
+
+ other -> returnNF_Tc NoInstance
+
+lookupInst dict@(Dict _ _ loc) = returnNF_Tc NoInstance
-- Methods
-lookupInst inst@(Method _ id tys theta _ orig loc)
- = newDictsAtLoc orig loc theta `thenNF_Tc` \ (dicts, dict_ids) ->
- returnNF_Tc (GenInst dicts (mkHsDictApp (mkHsTyApp (HsVar id) tys) dict_ids))
+lookupInst inst@(Method _ id tys theta _ loc)
+ = newDictsAtLoc loc theta `thenNF_Tc` \ dicts ->
+ returnNF_Tc (GenInst dicts (mkHsDictApp (mkHsTyApp (HsVar id) tys) (map instToId dicts)))
-- Literals
-lookupInst inst@(LitInst u (OverloadedIntegral i) ty orig loc)
+lookupInst inst@(LitInst u (HsIntegral i) ty loc)
| isIntTy ty && in_int_range -- Short cut for Int
= returnNF_Tc (GenInst [] int_lit)
-- GenInst, not SimpleInst, because int_lit is actually a constructor application
| isIntegerTy ty -- Short cut for Integer
= returnNF_Tc (GenInst [] integer_lit)
- | in_int_range -- It's overloaded but small enough to fit into an Int
- = tcLookupGlobalValueByKey fromIntClassOpKey `thenNF_Tc` \ from_int ->
- newMethodAtLoc orig loc from_int [ty] `thenNF_Tc` \ (method_inst, method_id) ->
- returnNF_Tc (GenInst [method_inst] (HsApp (HsVar method_id) int_lit))
-
| otherwise -- Alas, it is overloaded and a big literal!
- = tcLookupGlobalValueByKey fromIntegerClassOpKey `thenNF_Tc` \ from_integer ->
- newMethodAtLoc orig loc from_integer [ty] `thenNF_Tc` \ (method_inst, method_id) ->
+ = tcLookupSyntaxId fromIntegerName `thenNF_Tc` \ from_integer ->
+ newMethodAtLoc loc from_integer [ty] `thenNF_Tc` \ (method_inst, method_id) ->
returnNF_Tc (GenInst [method_inst] (HsApp (HsVar method_id) integer_lit))
where
in_int_range = inIntRange i
- intprim_lit = HsLitOut (HsIntPrim i) intPrimTy
- integer_lit = HsLitOut (HsInt i) integerTy
- int_lit = HsApp (HsVar (RealId intDataCon)) intprim_lit
+ integer_lit = HsLit (HsInteger i)
+ int_lit = HsLit (HsInt i)
+
+-- similar idea for overloaded floating point literals: if the literal is
+-- *definitely* a float or a double, generate the real thing here.
+-- This is essential (see nofib/spectral/nucleic).
-lookupInst inst@(LitInst u (OverloadedFractional f) ty orig loc)
- = tcLookupGlobalValueByKey fromRationalClassOpKey `thenNF_Tc` \ from_rational ->
+lookupInst inst@(LitInst u (HsFractional f) ty loc)
+ | isFloatTy ty = returnNF_Tc (GenInst [] float_lit)
+ | isDoubleTy ty = returnNF_Tc (GenInst [] double_lit)
- -- The type Rational isn't wired in so we have to conjure it up
- tcLookupTyConByKey rationalTyConKey `thenNF_Tc` \ rational_tycon ->
+ | otherwise
+ = tcLookupSyntaxId fromRationalName `thenNF_Tc` \ from_rational ->
+ newMethodAtLoc loc from_rational [ty] `thenNF_Tc` \ (method_inst, method_id) ->
let
- rational_ty = mkSynTy rational_tycon []
- rational_lit = HsLitOut (HsFrac f) rational_ty
+ rational_ty = funArgTy (idType method_id)
+ rational_lit = HsLit (HsRat f rational_ty)
in
- newMethodAtLoc orig loc from_rational [ty] `thenNF_Tc` \ (method_inst, method_id) ->
returnNF_Tc (GenInst [method_inst] (HsApp (HsVar method_id) rational_lit))
+
+ where
+ floatprim_lit = HsLit (HsFloatPrim f)
+ float_lit = mkHsConApp floatDataCon [] [floatprim_lit]
+ doubleprim_lit = HsLit (HsDoublePrim f)
+ double_lit = mkHsConApp doubleDataCon [] [doubleprim_lit]
\end{code}
There is a second, simpler interface, when you want an instance of a
ambiguous dictionaries.
\begin{code}
-lookupSimpleInst :: ClassInstEnv
- -> Class
- -> [Type] -- Look up (c,t)
- -> NF_TcM s (Maybe ThetaType) -- Here are the needed (c,t)s
-
-lookupSimpleInst class_inst_env clas tys
- = case matchSpecEnv class_inst_env tys of
- Nothing -> returnNF_Tc Nothing
-
- Just (tenv, dfun)
- -> returnNF_Tc (Just (instantiateThetaTy tenv theta))
+lookupSimpleInst :: Class
+ -> [Type] -- Look up (c,t)
+ -> NF_TcM (Maybe [(Class,[Type])]) -- Here are the needed (c,t)s
+
+lookupSimpleInst clas tys
+ = tcGetInstEnv `thenNF_Tc` \ inst_env ->
+ case lookupInstEnv inst_env clas tys of
+ FoundInst tenv dfun
+ -> returnNF_Tc (Just (substClasses (mkSubst emptyInScopeSet tenv) theta'))
where
(_, theta, _) = splitSigmaTy (idType dfun)
-\end{code}
-
+ theta' = classesOfPreds theta
-\begin{code}
-addClassInst
- :: ClassInstEnv -- Incoming envt
- -> [Type] -- The instance types: inst_tys
- -> Id -- Dict fun id to apply. Free tyvars of inst_ty must
- -- be the same as the forall'd tyvars of the dfun id.
- -> MaybeErr
- ClassInstEnv -- Success
- ([Type], Id) -- Offending overlap
-
-addClassInst inst_env inst_tys dfun_id = addToSpecEnv inst_env inst_tys dfun_id
+ other -> returnNF_Tc Nothing
\end{code}
-
-%************************************************************************
-%* *
-\subsection[Inst-origin]{The @InstOrigin@ type}
-%* *
-%************************************************************************
-
-The @InstOrigin@ type gives information about where a dictionary came from.
-This is important for decent error message reporting because dictionaries
-don't appear in the original source code. Doubtless this type will evolve...
-
-\begin{code}
-data InstOrigin s
- = OccurrenceOf (TcIdOcc s) -- Occurrence of an overloaded identifier
- | OccurrenceOfCon Id -- Occurrence of a data constructor
-
- | RecordUpdOrigin
-
- | DataDeclOrigin -- Typechecking a data declaration
-
- | InstanceDeclOrigin -- Typechecking an instance decl
-
- | LiteralOrigin HsLit -- Occurrence of a literal
-
- | ArithSeqOrigin RenamedArithSeqInfo -- [x..], [x..y] etc
-
- | SignatureOrigin -- A dict created from a type signature
- | Rank2Origin -- A dict created when typechecking the argument
- -- of a rank-2 typed function
-
- | DoOrigin -- The monad for a do expression
-
- | ClassDeclOrigin -- Manufactured during a class decl
-
- | InstanceSpecOrigin Class -- in a SPECIALIZE instance pragma
- Type
-
- -- When specialising instances the instance info attached to
- -- each class is not yet ready, so we record it inside the
- -- origin information. This is a bit of a hack, but it works
- -- fine. (Patrick is to blame [WDP].)
-
- | ValSpecOrigin Name -- in a SPECIALIZE pragma for a value
-
- -- Argument or result of a ccall
- -- Dictionaries with this origin aren't actually mentioned in the
- -- translated term, and so need not be bound. Nor should they
- -- be abstracted over.
-
- | CCallOrigin String -- CCall label
- (Maybe RenamedHsExpr) -- Nothing if it's the result
- -- Just arg, for an argument
-
- | LitLitOrigin String -- the litlit
-
- | UnknownOrigin -- Help! I give up...
-\end{code}
-
-\begin{code}
-pprOrigin :: Inst s -> SDoc
-pprOrigin inst
- = hsep [text "arising from", pp_orig orig, text "at", ppr locn]
- where
- (orig, locn) = case inst of
- Dict _ _ _ orig loc -> (orig,loc)
- Method _ _ _ _ _ orig loc -> (orig,loc)
- LitInst _ _ _ orig loc -> (orig,loc)
-
- pp_orig (OccurrenceOf id)
- = hsep [ptext SLIT("use of"), quotes (ppr id)]
- pp_orig (OccurrenceOfCon id)
- = hsep [ptext SLIT("use of"), quotes (ppr id)]
- pp_orig (LiteralOrigin lit)
- = hsep [ptext SLIT("the literal"), quotes (ppr lit)]
- pp_orig (InstanceDeclOrigin)
- = ptext SLIT("an instance declaration")
- pp_orig (ArithSeqOrigin seq)
- = hsep [ptext SLIT("the arithmetic sequence"), quotes (ppr seq)]
- pp_orig (SignatureOrigin)
- = ptext SLIT("a type signature")
- pp_orig (Rank2Origin)
- = ptext SLIT("a function with an overloaded argument type")
- pp_orig (DoOrigin)
- = ptext SLIT("a do statement")
- pp_orig (ClassDeclOrigin)
- = ptext SLIT("a class declaration")
- pp_orig (InstanceSpecOrigin clas ty)
- = hsep [text "a SPECIALIZE instance pragma; class",
- quotes (ppr clas), text "type:", ppr ty]
- pp_orig (ValSpecOrigin name)
- = hsep [ptext SLIT("a SPECIALIZE user-pragma for"), quotes (ppr name)]
- pp_orig (CCallOrigin clabel Nothing{-ccall result-})
- = hsep [ptext SLIT("the result of the _ccall_ to"), quotes (text clabel)]
- pp_orig (CCallOrigin clabel (Just arg_expr))
- = hsep [ptext SLIT("an argument in the _ccall_ to"), quotes (text clabel) <> comma,
- text "namely", quotes (ppr arg_expr)]
- pp_orig (LitLitOrigin s)
- = hsep [ptext SLIT("the ``literal-literal''"), quotes (text s)]
- pp_orig (UnknownOrigin)
- = ptext SLIT("...oops -- I don't know where the overloading came from!")
-\end{code}
projects / ghc-hetmet.git / blobdiff