X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Ftypecheck%2FTcClassDcl.lhs;h=2d113b7bb57c030026948d6ba72c058b54347016;hp=b36192cf03b3e8d8dd75a30a56105382171c930b;hb=77166b1729061531eeb77c33f4d3b2581f7d4c41;hpb=901f574d7b472053cae3bece13c1e4dd31810667 diff --git a/compiler/typecheck/TcClassDcl.lhs b/compiler/typecheck/TcClassDcl.lhs index b36192c..2d113b7 100644 --- a/compiler/typecheck/TcClassDcl.lhs +++ b/compiler/typecheck/TcClassDcl.lhs @@ -7,7 +7,7 @@ Typechecking class declarations \begin{code} module TcClassDcl ( tcClassSigs, tcClassDecl2, - findMethodBind, tcMethodBind, + findMethodBind, instantiateMethod, tcInstanceMethodBody, mkGenericDefMethBind, getGenericInstances, mkDefMethRdrName, tcAddDeclCtxt, badMethodErr, badATErr, omittedATWarn ) where @@ -22,6 +22,7 @@ import Inst import InstEnv import TcEnv import TcBinds +import TcSimplify import TcHsType import TcMType import TcType @@ -29,30 +30,27 @@ import TcRnMonad import Generics import Class import TyCon -import Type import MkId import Id import Name import Var import NameEnv import NameSet -import OccName import RdrName import Outputable import PrelNames import DynFlags import ErrUtils import Util -import Unique import ListSetOps import SrcLoc import Maybes -import List import BasicTypes import Bag import FastString import Control.Monad +import Data.List \end{code} @@ -162,13 +160,13 @@ tcClassSig _ s = pprPanic "tcClassSig" (ppr s) \begin{code} tcClassDecl2 :: LTyClDecl Name -- The class declaration - -> TcM (LHsBinds Id, [Id]) + -> TcM ([Id], LHsBinds Id) tcClassDecl2 (L loc (ClassDecl {tcdLName = class_name, tcdSigs = sigs, tcdMeths = default_binds})) - = recoverM (return (emptyLHsBinds, [])) $ - setSrcSpan loc $ do - clas <- tcLookupLocatedClass class_name + = recoverM (return ([], emptyLHsBinds)) $ + setSrcSpan loc $ + do { clas <- tcLookupLocatedClass class_name -- We make a separate binding for each default method. -- At one time I used a single AbsBinds for all of them, thus @@ -178,63 +176,138 @@ tcClassDecl2 (L loc (ClassDecl {tcdLName = class_name, tcdSigs = sigs, -- dm1 = \d -> case ds d of (a,b,c) -> a -- And since ds is big, it doesn't get inlined, so we don't get good -- default methods. Better to make separate AbsBinds for each - let - (tyvars, _, _, op_items) = classBigSig clas - rigid_info = ClsSkol clas - prag_fn = mkPragFun sigs - sig_fn = mkTcSigFun sigs - clas_tyvars = tcSkolSigTyVars rigid_info tyvars - tc_dm = tcDefMeth clas_tyvars default_binds - sig_fn prag_fn - -- tc_dm is called only for a sel_id - -- that has a binding in default_binds - - dm_sel_ids = [sel_id | (sel_id, DefMeth) <- op_items] - -- Generate code for polymorphic default methods only - -- (Generic default methods have turned into instance decls by now.) - -- This is incompatible with Hugs, which expects a polymorphic - -- default method for every class op, regardless of whether or not - -- the programmer supplied an explicit default decl for the class. - -- (If necessary we can fix that, but we don't have a convenient Id to hand.) - - (defm_binds, dm_ids) <- mapAndUnzipM tc_dm dm_sel_ids - return (unionManyBags defm_binds, dm_ids) + ; let + (tyvars, _, _, op_items) = classBigSig clas + rigid_info = ClsSkol clas + prag_fn = mkPragFun sigs default_binds + sig_fn = mkTcSigFun sigs + clas_tyvars = tcSkolSigTyVars rigid_info tyvars + pred = mkClassPred clas (mkTyVarTys clas_tyvars) + ; inst_loc <- getInstLoc (SigOrigin rigid_info) + ; this_dict <- newDictBndr inst_loc pred + + ; let tc_dm = tcDefMeth clas clas_tyvars + this_dict default_binds + sig_fn prag_fn + -- tc_dm is called only for a sel_id + -- that has a binding in default_binds + + dm_sel_ids = [sel_id | (sel_id, DefMeth) <- op_items] + -- Generate code for polymorphic default methods only (hence DefMeth) + -- (Generic default methods have turned into instance decls by now.) + -- This is incompatible with Hugs, which expects a polymorphic + -- default method for every class op, regardless of whether or not + -- the programmer supplied an explicit default decl for the class. + -- (If necessary we can fix that, but we don't have a convenient Id to hand.) + + ; (dm_ids, defm_binds) <- tcExtendTyVarEnv clas_tyvars $ + mapAndUnzipM tc_dm dm_sel_ids + + ; return (dm_ids, listToBag defm_binds) } + tcClassDecl2 d = pprPanic "tcClassDecl2" (ppr d) -tcDefMeth :: [TyVar] -> LHsBinds Name +tcDefMeth :: Class -> [TyVar] -> Inst -> LHsBinds Name -> TcSigFun -> TcPragFun -> Id - -> TcM (LHsBinds Id, Id) -tcDefMeth tyvars binds_in sig_fn prag_fn sel_id + -> TcM (Id, LHsBind Id) +tcDefMeth clas tyvars this_dict binds_in sig_fn prag_fn sel_id = do { let sel_name = idName sel_id ; dm_name <- lookupTopBndrRn (mkDefMethRdrName sel_name) - ; uniq <- newUnique - ; let dm_ty = idType sel_id -- Same as dict selector! - local_dm_name = setNameUnique sel_name uniq - local_dm_id = mkLocalId local_dm_name dm_ty - top_dm_id = mkDefaultMethodId dm_name dm_ty - all_tvs = map tyVarName tyvars ++ (sig_fn sel_name `orElse` []) - -- Tyvars in scope are *both* the ones from the - -- class decl *and* ones from the method sig + ; local_dm_name <- newLocalName sel_name + -- Base the local_dm_name on the selector name, becuase + -- type errors from tcInstanceMethodBody come from here + + -- See Note [Silly default-method bind] + -- (possibly out of date) ; let meth_bind = findMethodBind sel_name local_dm_name binds_in `orElse` pprPanic "tcDefMeth" (ppr sel_id) -- We only call tcDefMeth on selectors for which -- there is a binding in binds_in - ; tc_meth_bind <- tcMethodBind all_tvs (prag_fn sel_name) - local_dm_id meth_bind - - -- See Note [Silly default-method bind] - ; let loc = getLoc meth_bind - top_bind = L loc $ VarBind top_dm_id $ - L loc $ HsWrap (WpLet tc_meth_bind) $ - HsVar local_dm_id - - ; return (unitBag top_bind, top_dm_id) } + dm_sig_fn _ = sig_fn sel_name + dm_ty = idType sel_id + dm_id = mkDefaultMethodId dm_name dm_ty + local_dm_type = instantiateMethod clas sel_id (mkTyVarTys tyvars) + local_dm_id = mkLocalId local_dm_name local_dm_type + + ; (dm_id_w_inline, spec_prags) + <- tcPrags NonRecursive False True dm_id (prag_fn sel_name) + + ; warnTc (not (null spec_prags)) + (ptext (sLit "Ignoring SPECIALISE pragmas on default method") + <+> quotes (ppr sel_name)) + + ; tcInstanceMethodBody (instLoc this_dict) + tyvars [this_dict] + ([], emptyBag) + dm_id_w_inline local_dm_id + dm_sig_fn IsDefaultMethod meth_bind } + +--------------- +tcInstanceMethodBody :: InstLoc -> [TcTyVar] -> [Inst] + -> ([Inst], LHsBinds Id) -> Id -> Id + -> TcSigFun -> TcSpecPrags -> LHsBind Name + -> TcM (Id, LHsBind Id) +tcInstanceMethodBody inst_loc tyvars dfun_dicts + (this_dict, this_bind) meth_id local_meth_id + meth_sig_fn spec_prags bind@(L loc _) + = do { -- Typecheck the binding, first extending the envt + -- so that when tcInstSig looks up the local_meth_id to find + -- its signature, we'll find it in the environment + ; ((tc_bind, _), lie) <- getLIE $ + tcExtendIdEnv [local_meth_id] $ + tcPolyBinds TopLevel meth_sig_fn no_prag_fn + NonRecursive NonRecursive + (unitBag bind) + + ; let avails = this_dict ++ dfun_dicts + -- Only need the this_dict stuff if there are type + -- variables involved; otherwise overlap is not possible + -- See Note [Subtle interaction of recursion and overlap] + -- in TcInstDcls + ; lie_binds <- tcSimplifyCheck inst_loc tyvars avails lie + + ; let full_bind = AbsBinds tyvars dfun_lam_vars + [(tyvars, meth_id, local_meth_id, spec_prags)] + (this_bind `unionBags` lie_binds + `unionBags` tc_bind) + + dfun_lam_vars = map instToVar dfun_dicts -- Includes equalities + + ; return (meth_id, L loc full_bind) } + where + no_prag_fn _ = [] -- No pragmas for local_meth_id; + -- they are all for meth_id +\end{code} +\begin{code} mkDefMethRdrName :: Name -> RdrName mkDefMethRdrName sel_name = mkDerivedRdrName sel_name mkDefaultMethodOcc +instantiateMethod :: Class -> Id -> [TcType] -> TcType +-- Take a class operation, say +-- op :: forall ab. C a => forall c. Ix c => (b,c) -> a +-- Instantiate it at [ty1,ty2] +-- Return the "local method type": +-- forall c. Ix x => (ty2,c) -> ty1 +instantiateMethod clas sel_id inst_tys + = ASSERT( ok_first_pred ) local_meth_ty + where + (sel_tyvars,sel_rho) = tcSplitForAllTys (idType sel_id) + rho_ty = ASSERT( length sel_tyvars == length inst_tys ) + substTyWith sel_tyvars inst_tys sel_rho + + (first_pred, local_meth_ty) = tcSplitPredFunTy_maybe rho_ty + `orElse` pprPanic "tcInstanceMethod" (ppr sel_id) + + ok_first_pred = case getClassPredTys_maybe first_pred of + Just (clas1, _tys) -> clas == clas1 + Nothing -> False + -- The first predicate should be of form (C a b) + -- where C is the class in question + + --------------------------- -- The renamer just puts the selector ID as the binder in the method binding -- but we must use the method name; so we substitute it here. Crude but simple. @@ -248,30 +321,6 @@ findMethodBind sel_name meth_name binds | op_name == sel_name = Just (L loc1 (bind { fun_id = L loc2 meth_name })) f _other = Nothing - ---------------------------- -tcMethodBind :: [Name] -> [LSig Name] -> Id - -> LHsBind Name -> TcM (LHsBinds Id) -tcMethodBind tyvars prags meth_id bind - = do { let sig_fn _ = Just tyvars - prag_fn _ = prags - - -- Typecheck the binding, first extending the envt - -- so that when tcInstSig looks up the meth_id to find - -- its signature, we'll find it in the environment - -- - -- If scoped type variables is on, they are brought - -- into scope by tcPolyBinds (via sig_fn) - -- - -- See Note [Polymorphic methods] - ; traceTc (text "tcMethodBind" <+> ppr meth_id <+> ppr tyvars) - ; (tc_binds, ids) <- tcExtendIdEnv [meth_id] $ - tcPolyBinds TopLevel sig_fn prag_fn - NonRecursive NonRecursive - (unitBag bind) - - ; ASSERT( ids == [meth_id] ) -- Binding for ONE method - return tc_binds } \end{code} Note [Polymorphic methods] @@ -330,7 +379,6 @@ gives rise to the instance declarations instance C 1 where op Unit = ... - \begin{code} mkGenericDefMethBind :: Class -> [Type] -> Id -> Name -> TcM (LHsBind Name) mkGenericDefMethBind clas inst_tys sel_id meth_name @@ -416,7 +464,7 @@ get_generics decl@(ClassDecl {tcdLName = class_name, tcdMeths = def_methods}) group `lengthExceeds` 1] get_uniq (tc,_) = getUnique tc - mapM (addErrTc . dupGenericInsts) bad_groups + mapM_ (addErrTc . dupGenericInsts) bad_groups -- Check that there is an InstInfo for each generic type constructor let @@ -500,7 +548,7 @@ mkGenericInstance clas (hs_ty, binds) = do dfun_id = mkDictFunId dfun_name tyvars inst_theta clas [inst_ty] ispec = mkLocalInstance dfun_id overlap_flag - return (InstInfo { iSpec = ispec, iBinds = VanillaInst binds [] }) + return (InstInfo { iSpec = ispec, iBinds = VanillaInst binds [] False }) \end{code}