X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2Ftypecheck%2FInst.lhs;h=64f831aca702ea2727d2c8b1128b7766ffa67c37;hb=9dd6e1c216993624a2cd74b62ca0f0569c02c26b;hp=9e23da42ff06517bd0456c86a74fef3260efd5b7;hpb=9c26739695219d8343505a88457cb55c76b65449;p=ghc-hetmet.git diff --git a/ghc/compiler/typecheck/Inst.lhs b/ghc/compiler/typecheck/Inst.lhs index 9e23da4..64f831a 100644 --- a/ghc/compiler/typecheck/Inst.lhs +++ b/ghc/compiler/typecheck/Inst.lhs @@ -4,77 +4,72 @@ \section[Inst]{The @Inst@ type: dictionaries or method instances} \begin{code} -#include "HsVersions.h" - module Inst ( - Inst(..), -- Visible only to TcSimplify + LIE, emptyLIE, unitLIE, plusLIE, consLIE, zonkLIE, plusLIEs, mkLIE, + pprInsts, pprInstsInFull, - InstOrigin(..), OverloadedLit(..), - SYN_IE(LIE), emptyLIE, unitLIE, plusLIE, consLIE, zonkLIE, plusLIEs, + Inst, OverloadedLit(..), pprInst, - SYN_IE(InstanceMapper), + InstanceMapper, - newDicts, newDictsAtLoc, newMethod, newMethodWithGivenTy, newOverloadedLit, + newDictFromOld, newDicts, newDictsAtLoc, + newMethod, newMethodWithGivenTy, newOverloadedLit, - instType, tyVarsOfInst, lookupInst, lookupSimpleInst, + tyVarsOfInst, instLoc, getDictClassTys, - isDict, isTyVarDict, + lookupInst, lookupSimpleInst, LookupInstResult(..), + + isDict, isTyVarDict, isStdClassTyVarDict, isMethodFor, + instBindingRequired, instCanBeGeneralised, zonkInst, instToId, - matchesInst, - instBindingRequired, instCanBeGeneralised, - - pprInst + InstOrigin(..), pprOrigin ) where -IMP_Ubiq() -IMPORT_1_3(Ratio(Rational)) - -import HsSyn ( HsLit(..), HsExpr(..), HsBinds, Fixity, MonoBinds(..), - InPat, OutPat, Stmt, DoOrListComp, Match, GRHSsAndBinds, - ArithSeqInfo, HsType, Fake ) -import RnHsSyn ( SYN_IE(RenamedArithSeqInfo), SYN_IE(RenamedHsExpr) ) -import TcHsSyn ( TcIdOcc(..), SYN_IE(TcExpr), SYN_IE(TcIdBndr), - SYN_IE(TcDictBinds), SYN_IE(TcMonoBinds), - mkHsTyApp, mkHsDictApp, tcIdTyVars ) +#include "HsVersions.h" +import HsSyn ( HsLit(..), HsExpr(..), MonoBinds(..) ) +import RnHsSyn ( RenamedArithSeqInfo, RenamedHsExpr ) +import TcHsSyn ( TcExpr, TcIdOcc(..), TcIdBndr, + TcDictBinds, TcMonoBinds, + mkHsTyApp, mkHsDictApp, tcIdTyVars, zonkTcId + ) import TcMonad import TcEnv ( tcLookupGlobalValueByKey, tcLookupTyConByKey ) -import TcType ( SYN_IE(TcType), SYN_IE(TcRhoType), TcMaybe, SYN_IE(TcTyVarSet), - tcInstType, zonkTcType, tcSplitForAllTy, tcSplitRhoTy ) - -import Bag ( emptyBag, unitBag, unionBags, unionManyBags, +import TcType ( TcThetaType, + TcType, TcRhoType, TcTauType, TcMaybe, TcTyVarSet, + tcInstType, zonkTcType, zonkTcTypes, tcSplitForAllTy, tcSplitRhoTy, + zonkTcThetaType + ) +import Bag ( emptyBag, unitBag, unionBags, unionManyBags, bagToList, listToBag, consBag, Bag ) import Class ( classInstEnv, - SYN_IE(Class), GenClass, SYN_IE(ClassInstEnv), SYN_IE(ClassOp) + Class, ClassInstEnv ) -import ErrUtils ( addErrLoc, SYN_IE(Error) ) -import Id ( GenId, idType, mkInstId, SYN_IE(Id) ) -import PrelInfo ( isCcallishClass, isNoDictClass ) -import MatchEnv ( lookupMEnv, insertMEnv ) +import Id ( idType, mkUserLocal, mkSysLocal, Id, + GenIdSet, elementOfIdSet + ) +import PrelInfo ( isStandardClass, isCcallishClass, isNoDictClass ) import Name ( OccName(..), Name, mkLocalName, mkSysLocalName, occNameString, getOccName ) -import Outputable -import PprType ( GenClass, TyCon, GenType, GenTyVar, pprParendGenType ) -import Pretty -import SpecEnv ( SpecEnv ) -import SrcLoc ( SrcLoc, noSrcLoc ) -import Type ( GenType, eqSimpleTy, instantiateTy, - isTyVarTy, mkDictTy, splitForAllTy, splitSigmaTy, +import PprType ( TyCon, pprConstraint ) +import SpecEnv ( SpecEnv, matchSpecEnv, addToSpecEnv ) +import SrcLoc ( SrcLoc ) +import Type ( Type, ThetaType, instantiateTy, instantiateThetaTy, matchTys, + isTyVarTy, mkDictTy, splitForAllTys, splitSigmaTy, splitRhoTy, matchTy, tyVarsOfType, tyVarsOfTypes, - mkSynTy, SYN_IE(Type) + mkSynTy ) -import TyVar ( unionTyVarSets, GenTyVar ) +import TyVar ( zipTyVarEnv, lookupTyVarEnv, unionTyVarSets ) import TysPrim ( intPrimTy ) -import TysWiredIn ( intDataCon, integerTy ) -import Unique ( showUnique, fromRationalClassOpKey, rationalTyConKey, +import TysWiredIn ( intDataCon, integerTy, isIntTy, isIntegerTy, inIntRange ) +import Unique ( fromRationalClassOpKey, rationalTyConKey, fromIntClassOpKey, fromIntegerClassOpKey, Unique ) -import Util ( panic, zipEqual, zipWithEqual, assoc, assertPanic, pprTrace{-ToDo:rm-} ) -#if __GLASGOW_HASKELL__ >= 202 -import Maybes -#endif +import Maybes ( MaybeErr, expectJust ) +import Util ( thenCmp, zipEqual, zipWithEqual, isIn ) +import Outputable \end{code} %************************************************************************ @@ -88,12 +83,22 @@ type LIE s = Bag (Inst s) 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 zonkLIE :: LIE s -> NF_TcM s (LIE s) zonkLIE lie = mapBagNF_Tc zonkInst lie + +pprInsts :: [Inst s] -> SDoc +pprInsts insts = parens (hsep (punctuate comma (map pprInst insts))) + + +pprInstsInFull insts + = vcat (map go insts) + where + go inst = quotes (ppr inst) <+> pprOrigin inst \end{code} %************************************************************************ @@ -114,8 +119,8 @@ type Int, represented by data Inst s = Dict Unique - Class -- The type of the dict is (c t), where - (TcType s) -- c is the class and t the type; + Class -- The type of the dict is (c ts), where + [TcType s] -- c is the class and ts the types; (InstOrigin s) SrcLoc @@ -133,15 +138,17 @@ data Inst s -- should be instantiated. -- These types must saturate the Id's foralls. - (TcRhoType s) -- Cached: (type-of-id applied to inst_tys) - -- If this type is (theta => tau) then the type of the Method - -- is tau, and the method can be built by saying - -- id inst_tys dicts - -- where dicts are constructed from theta + (TcThetaType s) -- The (types of the) dictionaries to which the function + -- must be applied to get the method + + (TcTauType s) -- The type of the method (InstOrigin s) SrcLoc + -- INVARIANT: in (Method u f tys theta tau loc) + -- type of (f tys dicts(from theta)) = tau + | LitInst Unique OverloadedLit @@ -152,46 +159,138 @@ data Inst s data OverloadedLit = OverloadedIntegral Integer -- The number | OverloadedFractional Rational -- The number +\end{code} + +Ordering +~~~~~~~~ +@Insts@ are ordered by their class/type info, rather than by their +unique. This allows the context-reduction mechanism to use standard finite +maps to do their stuff. + +\begin{code} +instance Ord (Inst s) where + compare = cmpInst + +instance Eq (Inst s) 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 (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 + +cmpOverLit (OverloadedIntegral i1) (OverloadedIntegral i2) = i1 `compare` i2 +cmpOverLit (OverloadedFractional f1) (OverloadedFractional f2) = f1 `compare` f2 +cmpOverLit (OverloadedIntegral _) (OverloadedFractional _) = LT +cmpOverLit (OverloadedFractional _) (OverloadedIntegral _) = GT +\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 -getInstOrigin (Dict u clas ty origin loc) = origin -getInstOrigin (Method u clas ty rho origin loc) = origin -getInstOrigin (LitInst u lit ty origin loc) = origin +instLoc (Dict u clas tys origin loc) = loc +instLoc (Method u clas ty _ _ origin loc) = loc +instLoc (LitInst u lit ty origin loc) = loc + +getDictClassTys (Dict u clas tys _ _) = (clas, tys) + +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 + -- locally-overloaded class methods, for example +tyVarsOfInst (LitInst _ _ ty _ _) = tyVarsOfType ty \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 + = 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 +necessarily result in bindings. The first tells whether an @Inst@ +must be witnessed by an actual binding; the second tells whether an +@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 +\end{code} + + Construction ~~~~~~~~~~~~ \begin{code} newDicts :: InstOrigin s - -> [(Class, TcType s)] + -> TcThetaType s -> NF_TcM s (LIE s, [TcIdOcc s]) newDicts orig theta = tcGetSrcLoc `thenNF_Tc` \ loc -> newDictsAtLoc orig loc theta `thenNF_Tc` \ (dicts, ids) -> returnNF_Tc (listToBag dicts, ids) -{- - tcGetUniques (length theta) `thenNF_Tc` \ new_uniqs -> - let - mk_dict u (clas, ty) = Dict u clas ty orig loc - dicts = zipWithEqual "newDicts" mk_dict new_uniqs theta - in - returnNF_Tc (listToBag dicts, map instToId dicts) --} -- Local function, similar to newDicts, -- but with slightly different interface newDictsAtLoc :: InstOrigin s -> SrcLoc - -> [(Class, TcType s)] + -> 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, ty) = Dict u clas ty orig loc + 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] @@ -199,77 +298,84 @@ newMethod :: InstOrigin s newMethod orig id tys = -- Get the Id type and instantiate it at the specified types (case id of - RealId id -> let (tyvars, rho) = splitForAllTy (idType id) + RealId id -> let (tyvars, rho) = splitForAllTys (idType id) in - (if length tyvars /= length tys then pprTrace "newMethod" (ppr PprDebug (idType id)) else \x->x) $ - tcInstType (zip{-Equal "newMethod"-} tyvars tys) rho + ASSERT( length tyvars == length tys) + tcInstType (zipTyVarEnv tyvars tys) rho + TcId id -> tcSplitForAllTy (idType id) `thenNF_Tc` \ (tyvars, rho) -> - returnNF_Tc (instantiateTy (zipEqual "newMethod(2)" tyvars tys) rho) + returnNF_Tc (instantiateTy (zipTyVarEnv tyvars tys) rho) ) `thenNF_Tc` \ rho_ty -> + let + (theta, tau) = splitRhoTy rho_ty + in -- Our friend does the rest - newMethodWithGivenTy orig id tys rho_ty + newMethodWithGivenTy orig id tys theta tau -newMethodWithGivenTy orig id tys rho_ty +newMethodWithGivenTy orig id tys theta tau = tcGetSrcLoc `thenNF_Tc` \ loc -> tcGetUnique `thenNF_Tc` \ new_uniq -> let - meth_inst = Method new_uniq id tys rho_ty orig loc + meth_inst = Method new_uniq id tys theta tau orig loc in returnNF_Tc (unitLIE meth_inst, instToId meth_inst) -newMethodAtLoc :: InstOrigin s -> SrcLoc -> Id -> [TcType s] -> NF_TcM s (Inst s, TcIdOcc s) +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 = -- Get the Id type and instantiate it at the specified types let - (tyvars,rho) = splitForAllTy (idType real_id) + (tyvars,rho) = splitForAllTys (idType real_id) in - tcInstType (zipEqual "newMethodAtLoc" tyvars tys) rho `thenNF_Tc` \ rho_ty -> - tcGetUnique `thenNF_Tc` \ new_uniq -> + tcInstType (zipTyVarEnv tyvars tys) rho `thenNF_Tc` \ rho_ty -> + tcGetUnique `thenNF_Tc` \ new_uniq -> let - meth_inst = Method new_uniq (RealId real_id) tys rho_ty orig loc + (theta, tau) = splitRhoTy rho_ty + meth_inst = Method new_uniq (RealId real_id) tys theta tau orig loc in returnNF_Tc (meth_inst, instToId meth_inst) newOverloadedLit :: InstOrigin s -> OverloadedLit -> TcType s - -> NF_TcM s (LIE s, TcIdOcc s) -newOverloadedLit orig lit ty + -> NF_TcM s (TcExpr s, LIE s) +newOverloadedLit orig (OverloadedIntegral i) ty + | isIntTy ty && inIntRange i -- Short cut for Int + = returnNF_Tc (int_lit, emptyLIE) + + | isIntegerTy ty -- Short cut for Integer + = 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 + +newOverloadedLit orig lit ty -- The general case = tcGetSrcLoc `thenNF_Tc` \ loc -> tcGetUnique `thenNF_Tc` \ new_uniq -> let lit_inst = LitInst new_uniq lit ty orig loc in - returnNF_Tc (unitLIE lit_inst, instToId lit_inst) + 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 (mkInstId u (mkDictTy clas ty) (mkLocalName u str loc)) + = TcId (mkUserLocal occ u (mkDictTy clas ty) loc) where - str = VarOcc (SLIT("d.") _APPEND_ (occNameString (getOccName clas))) + occ = VarOcc (SLIT("d.") _APPEND_ (occNameString (getOccName clas))) -instToId (Method u id tys rho_ty orig loc) - = TcId (mkInstId u tau_ty (mkLocalName u occ loc)) - where - occ = getOccName id - (_, tau_ty) = splitRhoTy rho_ty - -- I hope we don't need tcSplitRhoTy... - -- NB The method Id has just the tau type +instToId (Method u id tys theta tau orig loc) + = TcId (mkUserLocal (getOccName id) u tau loc) instToId (LitInst u list ty orig loc) - = TcId (mkInstId u ty (mkSysLocalName u SLIT("lit") loc)) -\end{code} - -\begin{code} -instType :: Inst s -> TcType s -instType (Dict _ clas ty _ _) = mkDictTy clas ty -instType (LitInst _ _ ty _ _) = ty -instType (Method _ id tys ty _ _) = ty + = TcId (mkSysLocal SLIT("lit") u ty loc) \end{code} @@ -281,14 +387,17 @@ need, and it's a lot of extra work. \begin{code} zonkInst :: Inst s -> NF_TcM s (Inst s) -zonkInst (Dict u clas ty orig loc) - = zonkTcType ty `thenNF_Tc` \ new_ty -> - returnNF_Tc (Dict u clas new_ty orig loc) - -zonkInst (Method u id tys rho orig loc) -- Doesn't zonk the id! - = mapNF_Tc zonkTcType tys `thenNF_Tc` \ new_tys -> - zonkTcType rho `thenNF_Tc` \ new_rho -> - returnNF_Tc (Method u id new_tys new_rho orig loc) +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 + 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) zonkInst (LitInst u lit ty orig loc) = zonkTcType ty `thenNF_Tc` \ new_ty -> @@ -296,68 +405,6 @@ zonkInst (LitInst u lit ty orig loc) \end{code} -\begin{code} -tyVarsOfInst :: Inst s -> TcTyVarSet s -tyVarsOfInst (Dict _ _ ty _ _) = tyVarsOfType ty -tyVarsOfInst (Method _ id tys rho _ _) = tyVarsOfTypes tys `unionTyVarSets` tcIdTyVars id - -- The id might not be a RealId; in the case of - -- locally-overloaded class methods, for example -tyVarsOfInst (LitInst _ _ ty _ _) = tyVarsOfType ty -\end{code} - -@matchesInst@ checks when two @Inst@s are instances of the same -thing at the same type, even if their uniques differ. - -\begin{code} -matchesInst :: Inst s -> Inst s -> Bool - -matchesInst (Dict _ clas1 ty1 _ _) (Dict _ clas2 ty2 _ _) - = clas1 == clas2 && ty1 `eqSimpleTy` ty2 - -matchesInst (Method _ id1 tys1 _ _ _) (Method _ id2 tys2 _ _ _) - = id1 == id2 - && and (zipWith eqSimpleTy tys1 tys2) - && length tys1 == length tys2 - -matchesInst (LitInst _ lit1 ty1 _ _) (LitInst _ lit2 ty2 _ _) - = lit1 `eq` lit2 && ty1 `eqSimpleTy` ty2 - where - (OverloadedIntegral i1) `eq` (OverloadedIntegral i2) = i1 == i2 - (OverloadedFractional f1) `eq` (OverloadedFractional f2) = f1 == f2 - _ `eq` _ = False - -matchesInst other1 other2 = False -\end{code} - - -Predicates -~~~~~~~~~~ -\begin{code} -isDict :: Inst s -> Bool -isDict (Dict _ _ _ _ _) = True -isDict other = False - -isTyVarDict :: Inst s -> Bool -isTyVarDict (Dict _ _ ty _ _) = isTyVarTy ty -isTyVarDict other = False -\end{code} - -Two predicates which deal with the case where class constraints don't -necessarily result in bindings. The first tells whether an @Inst@ -must be witnessed by an actual binding; the second tells whether an -@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 -\end{code} - - Printing ~~~~~~~~ ToDo: improve these pretty-printing things. The ``origin'' is really only @@ -365,40 +412,27 @@ relevant in error messages. \begin{code} instance Outputable (Inst s) where - ppr sty inst = pprQuote sty (\ sty -> ppr_inst sty (\ o l -> empty) inst) - -pprInst sty inst = ppr_inst sty (\ o l -> pprOrigin o l sty) inst - -ppr_inst sty ppr_orig (LitInst u lit ty orig loc) - = hang (ppr_orig orig loc) - 4 (hsep [case lit of - OverloadedIntegral i -> integer i - OverloadedFractional f -> rational f, - ptext SLIT("at"), - ppr sty ty, - show_uniq sty u]) - -ppr_inst sty ppr_orig (Dict u clas ty orig loc) - = hang (ppr_orig orig loc) - 4 (pprQuote sty $ \ sty -> - hsep [ppr sty clas, pprParendGenType sty ty, show_uniq sty u]) - -ppr_inst sty ppr_orig (Method u id tys rho orig loc) - = hang (ppr_orig orig loc) - 4 (hsep [ppr sty id, ptext SLIT("at"), - pprQuote sty $ \ sty -> interppSP sty tys, - show_uniq sty u]) - -show_uniq PprDebug u = ppr PprDebug u -show_uniq sty u = empty -\end{code} + ppr inst = pprInst inst -Printing in error messages +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] -\begin{code} -noInstanceErr inst sty = hang (ptext SLIT("No instance for:")) 4 (ppr sty inst) +pprInst (Dict u clas tys orig loc) = pprConstraint clas tys <+> show_uniq u + +pprInst (Method u id tys _ _ orig loc) + = hsep [ppr id, ptext SLIT("at"), + interppSP tys, + show_uniq u] + +show_uniq u = ifPprDebug (text "{-" <> ppr u <> text "-}") \end{code} + %************************************************************************ %* * \subsection[InstEnv-types]{Type declarations} @@ -406,7 +440,7 @@ noInstanceErr inst sty = hang (ptext SLIT("No instance for:")) 4 (ppr sty inst) %************************************************************************ \begin{code} -type InstanceMapper = Class -> (ClassInstEnv, ClassOp -> SpecEnv) +type InstanceMapper = Class -> ClassInstEnv \end{code} A @ClassInstEnv@ lives inside a class, and identifies all the instances @@ -425,58 +459,69 @@ 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 - -> TcM s ([Inst s], - TcDictBinds s) -- The new binding + -> NF_TcM s (LookupInstResult s) -- Dictionaries -lookupInst dict@(Dict _ clas ty orig loc) - = case lookupMEnv matchTy (get_inst_env clas orig) ty of - Nothing -> tcAddSrcLoc loc $ - tcAddErrCtxt (pprOrigin orig loc) $ - failTc (noInstanceErr dict) +lookupInst dict@(Dict _ clas tys orig loc) + = case matchSpecEnv (classInstEnv clas) tys of - Just (dfun_id, tenv) + Just (tenv, dfun_id) -> let - (tyvars, rho) = splitForAllTy (idType dfun_id) - ty_args = map (assoc "lookupInst" tenv) tyvars - -- tenv should bind all the tyvars + (tyvars, rho) = splitForAllTys (idType dfun_id) + ty_args = map (expectJust "Inst" . lookupTyVarEnv tenv) tyvars + -- tenv should bind all the tyvars in tcInstType tenv rho `thenNF_Tc` \ dfun_rho -> let (theta, tau) = splitRhoTy dfun_rho + ty_app = mkHsTyApp (HsVar (RealId dfun_id)) ty_args in + if null theta then + returnNF_Tc (SimpleInst ty_app) + else newDictsAtLoc orig loc theta `thenNF_Tc` \ (dicts, dict_ids) -> let - rhs = mkHsDictApp (mkHsTyApp (HsVar (RealId dfun_id)) ty_args) dict_ids + rhs = mkHsDictApp ty_app dict_ids in - returnTc (dicts, VarMonoBind (instToId dict) rhs) + returnNF_Tc (GenInst dicts rhs) + Nothing -> returnNF_Tc NoInstance -- Methods -lookupInst inst@(Method _ id tys rho orig loc) - = tcSplitRhoTy rho `thenNF_Tc` \ (theta, _) -> - newDictsAtLoc orig loc theta `thenNF_Tc` \ (dicts, dict_ids) -> - returnTc (dicts, VarMonoBind (instToId inst) (mkHsDictApp (mkHsTyApp (HsVar id) tys) dict_ids)) +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)) -- Literals lookupInst inst@(LitInst u (OverloadedIntegral i) ty orig loc) - | i >= toInteger minInt && i <= toInteger maxInt - = -- 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) -> - returnTc ([method_inst], VarMonoBind (instToId inst) (HsApp (HsVar method_id) int_lit)) - - | otherwise - = -- Alas, it is overloaded and a big literal! - tcLookupGlobalValueByKey fromIntegerClassOpKey `thenNF_Tc` \ from_integer -> + | 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) -> - returnTc ([method_inst], VarMonoBind (instToId inst) (HsApp (HsVar method_id) (HsLitOut (HsInt i) integerTy))) + 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 lookupInst inst@(LitInst u (OverloadedFractional f) ty orig loc) @@ -489,7 +534,7 @@ lookupInst inst@(LitInst u (OverloadedFractional f) ty orig loc) rational_lit = HsLitOut (HsFrac f) rational_ty in newMethodAtLoc orig loc from_rational [ty] `thenNF_Tc` \ (method_inst, method_id) -> - returnTc ([method_inst], VarMonoBind (instToId inst) (HsApp (HsVar method_id) rational_lit)) + returnNF_Tc (GenInst [method_inst] (HsApp (HsVar method_id) rational_lit)) \end{code} There is a second, simpler interface, when you want an instance of a @@ -500,59 +545,31 @@ ambiguous dictionaries. \begin{code} lookupSimpleInst :: ClassInstEnv -> Class - -> Type -- Look up (c,t) - -> TcM s [(Class,Type)] -- Here are the needed (c,t)s - -lookupSimpleInst class_inst_env clas ty - = case (lookupMEnv matchTy class_inst_env ty) of - Nothing -> failTc (noSimpleInst clas ty) - Just (dfun,tenv) -> returnTc [(c,instantiateTy tenv t) | (c,t) <- theta] - where - (_, theta, _) = splitSigmaTy (idType dfun) - -noSimpleInst clas ty sty - = sep [ptext SLIT("No instance for class"), ppr sty clas, - ptext SLIT("at type"), ppr sty ty] -\end{code} - + -> [Type] -- Look up (c,t) + -> NF_TcM s (Maybe ThetaType) -- Here are the needed (c,t)s -@mkInstSpecEnv@ is used to construct the @SpecEnv@ for a dfun. -It does it by filtering the class's @InstEnv@. All pretty shady stuff. +lookupSimpleInst class_inst_env clas tys + = case matchSpecEnv class_inst_env tys of + Nothing -> returnNF_Tc Nothing -\begin{code} -mkInstSpecEnv clas inst_ty inst_tvs inst_theta = panic "mkInstSpecEnv" + Just (tenv, dfun) + -> returnNF_Tc (Just (instantiateThetaTy tenv theta)) + where + (_, theta, _) = splitSigmaTy (idType dfun) \end{code} -\begin{pseudocode} -mkInstSpecEnv :: Class -- class - -> Type -- instance type - -> [TyVarTemplate] -- instance tyvars - -> ThetaType -- superclasses dicts - -> SpecEnv -- specenv for dfun of instance - -mkInstSpecEnv clas inst_ty inst_tvs inst_theta - = mkSpecEnv (catMaybes (map maybe_spec_info matches)) - where - matches = matchMEnv matchTy (classInstEnv clas) inst_ty - - maybe_spec_info (_, match_info, MkInstTemplate dfun _ []) - = Just (SpecInfo (map (assocMaybe match_info) inst_tvs) (length inst_theta) dfun) - maybe_spec_info (_, match_info, _) - = Nothing -\end{pseudocode} - \begin{code} addClassInst :: ClassInstEnv -- Incoming envt - -> Type -- The instance type: inst_ty + -> [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 + ([Type], Id) -- Offending overlap -addClassInst inst_env inst_ty dfun_id = insertMEnv matchTy inst_env inst_ty dfun_id +addClassInst inst_env inst_tys dfun_id = addToSpecEnv inst_env inst_tys dfun_id \end{code} @@ -583,23 +600,14 @@ data InstOrigin s | 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 --- NO MORE! --- | DerivingOrigin InstanceMapper --- Class --- TyCon - - -- During "deriving" operations we have an ever changing - -- mapping of classes to instances, so we record it inside the - -- origin information. This is a bit of a hack, but it works - -- fine. (Simon is to blame [WDP].) - - | InstanceSpecOrigin InstanceMapper - Class -- in a SPECIALIZE instance pragma + | InstanceSpecOrigin Class -- in a SPECIALIZE instance pragma Type -- When specialising instances the instance info attached to @@ -607,8 +615,6 @@ data InstOrigin s -- origin information. This is a bit of a hack, but it works -- fine. (Patrick is to blame [WDP].) --- | DefaultDeclOrigin -- Related to a `default' declaration - | ValSpecOrigin Name -- in a SPECIALIZE pragma for a value -- Argument or result of a ccall @@ -626,53 +632,45 @@ data InstOrigin s \end{code} \begin{code} --- During deriving and instance specialisation operations --- we can't get the instances of the class from inside the --- class, because the latter ain't ready yet. Instead we --- find a mapping from classes to envts inside the dict origin. - -get_inst_env :: Class -> InstOrigin s -> ClassInstEnv --- get_inst_env clas (DerivingOrigin inst_mapper _ _) --- = fst (inst_mapper clas) -get_inst_env clas (InstanceSpecOrigin inst_mapper _ _) - = fst (inst_mapper clas) -get_inst_env clas other_orig = classInstEnv clas - - -pprOrigin :: InstOrigin s -> SrcLoc -> Error - -pprOrigin orig locn sty - = hsep [text "arising from", pp_orig, text "at", ppr sty locn] +pprOrigin :: Inst s -> SDoc +pprOrigin inst + = hsep [text "arising from", pp_orig orig <> comma, text "at", ppr locn] where - pp_orig - = case orig of - OccurrenceOf id -> - hsep [ptext SLIT("use of"), ppr sty id] - OccurrenceOfCon id -> - hsep [ptext SLIT("use of"), ppr sty id] - LiteralOrigin lit -> - hsep [ptext SLIT("the literal"), ppr sty lit] - InstanceDeclOrigin -> - ptext SLIT("an instance declaration") - ArithSeqOrigin seq -> - hsep [ptext SLIT("the arithmetic sequence:"), ppr sty seq] - SignatureOrigin -> - ptext SLIT("a type signature") - DoOrigin -> - ptext SLIT("a do statement") - ClassDeclOrigin -> - ptext SLIT("a class declaration") - InstanceSpecOrigin _ clas ty -> - hsep [text "a SPECIALIZE instance pragma; class", - ppr sty clas, text "type:", ppr sty ty] - ValSpecOrigin name -> - hsep [ptext SLIT("a SPECIALIZE user-pragma for"), ppr sty name] - CCallOrigin clabel Nothing{-ccall result-} -> - hsep [ptext SLIT("the result of the _ccall_ to"), text clabel] - CCallOrigin clabel (Just arg_expr) -> - hsep [ptext SLIT("an argument in the _ccall_ to"), text clabel <> comma, text "namely", ppr sty arg_expr] - LitLitOrigin s -> - hcat [ptext SLIT("the ``literal-literal''"), text s] - UnknownOrigin -> - ptext SLIT("...oops -- I don't know where the overloading came from!") + (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", + ppr clas, text "type:", ppr ty] + pp_orig (ValSpecOrigin name) + = hsep [ptext SLIT("a SPECIALIZE user-pragma for"), ppr name] + pp_orig (CCallOrigin clabel Nothing{-ccall result-}) + = hsep [ptext SLIT("the result of the _ccall_ to"), 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}