X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Ftypecheck%2FTcInstDcls.lhs;h=27de2307747685c126141103d64909fa4582ee82;hp=0dbb77564f29a40a57d55a42ad962761334ddcaa;hb=7fc749a43b4b6b85d234fa95d4928648259584f4;hpb=940524aec90652b5ef81789c9a453c57c0e42cc9 diff --git a/compiler/typecheck/TcInstDcls.lhs b/compiler/typecheck/TcInstDcls.lhs index 0dbb775..27de230 100644 --- a/compiler/typecheck/TcInstDcls.lhs +++ b/compiler/typecheck/TcInstDcls.lhs @@ -6,6 +6,13 @@ TcInstDecls: Typechecking instance declarations \begin{code} +{-# OPTIONS -w #-} +-- The above warning supression flag is a temporary kludge. +-- While working on this module you are encouraged to remove it and fix +-- any warnings in the module. See +-- http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings +-- for details + module TcInstDcls ( tcInstDecls1, tcInstDecls2 ) where #include "HsVersions.h" @@ -29,6 +36,7 @@ import TcSimplify import Type import Coercion import TyCon +import TypeRep import DataCon import Class import Var @@ -179,7 +187,10 @@ tcInstDecls1 tycl_decls inst_decls deriv_decls -- (4) Compute instances from "deriving" clauses; -- This stuff computes a context for the derived instance -- decl, so it needs to know about all the instances possible - ; (deriv_inst_info, deriv_binds) <- tcDeriving tycl_decls deriv_decls + -- NB: class instance declarations can contain derivings as + -- part of associated data type declarations + ; (deriv_inst_info, deriv_binds) <- tcDeriving tycl_decls inst_decls + deriv_decls ; addInsts deriv_inst_info $ do { ; gbl_env <- getGblEnv @@ -254,7 +265,9 @@ tcLocalInstDecl1 decl@(L loc (InstDecl poly_ty binds uprags ats)) -- (This no longer includes the associated types.) ; dfun_name <- newDFunName clas inst_tys loc ; overlap_flag <- getOverlapFlag - ; let dfun = mkDictFunId dfun_name tyvars theta clas inst_tys + ; let (eq_theta,dict_theta) = partition isEqPred theta + theta' = eq_theta ++ dict_theta + dfun = mkDictFunId dfun_name tyvars theta' clas inst_tys ispec = mkLocalInstance dfun overlap_flag ; return ([InstInfo { iSpec = ispec, @@ -600,20 +613,30 @@ tcInstDecl2 (InstInfo { iSpec = ispec, iBinds = VanillaInst monobinds uprags }) -- Instantiate the super-class context with inst_tys sc_theta' = substTheta (zipOpenTvSubst class_tyvars inst_tys') sc_theta + (eq_sc_theta',dict_sc_theta') = partition isEqPred sc_theta' origin = SigOrigin rigid_info + (eq_dfun_theta',dict_dfun_theta') = partition isEqPred dfun_theta' in -- Create dictionary Ids from the specified instance contexts. getInstLoc InstScOrigin `thenM` \ sc_loc -> - newDictBndrs sc_loc sc_theta' `thenM` \ sc_dicts -> + newDictBndrs sc_loc dict_sc_theta' `thenM` \ sc_dicts -> getInstLoc origin `thenM` \ inst_loc -> - newDictBndrs inst_loc dfun_theta' `thenM` \ dfun_arg_dicts -> + mkMetaCoVars eq_sc_theta' `thenM` \ sc_covars -> + mkEqInsts eq_sc_theta' (map mkWantedCo sc_covars) `thenM` \ wanted_sc_eqs -> + mkCoVars eq_dfun_theta' `thenM` \ dfun_covars -> + mkEqInsts eq_dfun_theta' (map mkGivenCo $ mkTyVarTys dfun_covars) `thenM` \ dfun_eqs -> + newDictBndrs inst_loc dict_dfun_theta' `thenM` \ dfun_dicts -> newDictBndr inst_loc (mkClassPred clas inst_tys') `thenM` \ this_dict -> -- Default-method Ids may be mentioned in synthesised RHSs, -- but they'll already be in the environment. -- Typecheck the methods let -- These insts are in scope; quite a few, eh? - avail_insts = [this_dict] ++ dfun_arg_dicts ++ sc_dicts + dfun_insts = dfun_eqs ++ dfun_dicts + wanted_sc_insts = wanted_sc_eqs ++ sc_dicts + given_sc_eqs = map (updateEqInstCoercion (mkGivenCo . TyVarTy . fromWantedCo "tcInstDecl2") ) wanted_sc_eqs + given_sc_insts = given_sc_eqs ++ sc_dicts + avail_insts = [this_dict] ++ dfun_insts ++ given_sc_insts in tcMethods origin clas inst_tyvars' dfun_theta' inst_tys' avail_insts @@ -621,10 +644,10 @@ tcInstDecl2 (InstInfo { iSpec = ispec, iBinds = VanillaInst monobinds uprags }) -- Figure out bindings for the superclass context -- Don't include this_dict in the 'givens', else - -- sc_dicts get bound by just selecting from this_dict!! + -- wanted_sc_insts get bound by just selecting from this_dict!! addErrCtxt superClassCtxt (tcSimplifySuperClasses inst_loc - dfun_arg_dicts sc_dicts) `thenM` \ sc_binds -> + dfun_insts wanted_sc_insts) `thenM` \ sc_binds -> -- It's possible that the superclass stuff might unified one -- of the inst_tyavars' with something in the envt @@ -638,8 +661,8 @@ tcInstDecl2 (InstInfo { iSpec = ispec, iBinds = VanillaInst monobinds uprags }) dict_constr = classDataCon clas scs_and_meths = map instToId sc_dicts ++ meth_ids this_dict_id = instToId this_dict - inline_prag | null dfun_arg_dicts = [] - | otherwise = [L loc (InlinePrag (Inline AlwaysActive True))] + inline_prag | null dfun_insts = [] + | otherwise = [L loc (InlinePrag (Inline AlwaysActive True))] -- Always inline the dfun; this is an experimental decision -- because it makes a big performance difference sometimes. -- Often it means we can do the method selection, and then @@ -652,7 +675,7 @@ tcInstDecl2 (InstInfo { iSpec = ispec, iBinds = VanillaInst monobinds uprags }) -- See Note [Inline dfuns] below dict_rhs - = mkHsConApp dict_constr inst_tys' (map HsVar scs_and_meths) + = mkHsConApp dict_constr (inst_tys' ++ mkTyVarTys sc_covars) (map HsVar scs_and_meths) -- We don't produce a binding for the dict_constr; instead we -- rely on the simplifier to unfold this saturated application -- We do this rather than generate an HsCon directly, because @@ -664,15 +687,32 @@ tcInstDecl2 (InstInfo { iSpec = ispec, iBinds = VanillaInst monobinds uprags }) all_binds = dict_bind `consBag` (sc_binds `unionBags` meth_binds) main_bind = noLoc $ AbsBinds - inst_tyvars' - (map instToId dfun_arg_dicts) - [(inst_tyvars', dfun_id, this_dict_id, - inline_prag ++ prags)] + (inst_tyvars' ++ dfun_covars) + (map instToId dfun_dicts) + [(inst_tyvars' ++ dfun_covars, dfun_id, this_dict_id, inline_prag ++ prags)] all_binds in showLIE (text "instance") `thenM_` returnM (unitBag main_bind) +mkCoVars :: [PredType] -> TcM [TyVar] +mkCoVars [] = return [] +mkCoVars (pred:preds) = + do { uniq <- newUnique + ; let name = mkSysTvName uniq FSLIT("mkCoVars") + ; let tv = mkCoVar name (PredTy pred) + ; tvs <- mkCoVars preds + ; return (tv:tvs) + } + +mkMetaCoVars :: [PredType] -> TcM [TyVar] +mkMetaCoVars [] = return [] +mkMetaCoVars (EqPred ty1 ty2:preds) = + do { tv <- newMetaTyVar TauTv (mkCoKind ty1 ty2) + ; tvs <- mkMetaCoVars preds + ; return (tv:tvs) + } + tcMethods origin clas inst_tyvars' dfun_theta' inst_tys' avail_insts op_items monobinds uprags