diff options
Diffstat (limited to 'compiler/deSugar/DsUtils.hs')
| -rw-r--r-- | compiler/deSugar/DsUtils.hs | 78 |
1 files changed, 2 insertions, 76 deletions
diff --git a/compiler/deSugar/DsUtils.hs b/compiler/deSugar/DsUtils.hs index 7bec30acdc..4c30889858 100644 --- a/compiler/deSugar/DsUtils.hs +++ b/compiler/deSugar/DsUtils.hs @@ -282,18 +282,15 @@ data CaseAlt a = MkCaseAlt{ alt_pat :: a, alt_result :: MatchResult } mkCoAlgCaseMatchResult - :: DynFlags - -> Id -- Scrutinee + :: Id -- Scrutinee -> Type -- Type of exp -> [CaseAlt DataCon] -- Alternatives (bndrs *include* tyvars, dicts) -> MatchResult -mkCoAlgCaseMatchResult dflags var ty match_alts +mkCoAlgCaseMatchResult var ty match_alts | isNewtype -- Newtype case; use a let = ASSERT( null (tail match_alts) && null (tail arg_ids1) ) mkCoLetMatchResult (NonRec arg_id1 newtype_rhs) match_result1 - | isPArrFakeAlts match_alts - = MatchResult CanFail $ mkPArrCase dflags var ty (sort_alts match_alts) | otherwise = mkDataConCase var ty match_alts where @@ -311,34 +308,6 @@ mkCoAlgCaseMatchResult dflags var ty match_alts -- (not that splitTyConApp does, these days) newtype_rhs = unwrapNewTypeBody tc ty_args (Var var) - --- Stuff for parallel arrays - -- - -- Concerning `isPArrFakeAlts': - -- - -- * it is *not* sufficient to just check the type of the type - -- constructor, as we have to be careful not to confuse the real - -- representation of parallel arrays with the fake constructors; - -- moreover, a list of alternatives must not mix fake and real - -- constructors (this is checked earlier on) - -- - -- FIXME: We actually go through the whole list and make sure that - -- either all or none of the constructors are fake parallel - -- array constructors. This is to spot equations that mix fake - -- constructors with the real representation defined in - -- `PrelPArr'. It would be nicer to spot this situation - -- earlier and raise a proper error message, but it can really - -- only happen in `PrelPArr' anyway. - -- - - isPArrFakeAlts :: [CaseAlt DataCon] -> Bool - isPArrFakeAlts [alt] = isPArrFakeCon (alt_pat alt) - isPArrFakeAlts (alt:alts) = - case (isPArrFakeCon (alt_pat alt), isPArrFakeAlts alts) of - (True , True ) -> True - (False, False) -> False - _ -> panic "DsUtils: you may not mix `[:...:]' with `PArr' patterns" - isPArrFakeAlts [] = panic "DsUtils: unexpectedly found an empty list of PArr fake alternatives" - mkCoSynCaseMatchResult :: Id -> Type -> CaseAlt PatSyn -> MatchResult mkCoSynCaseMatchResult var ty alt = MatchResult CanFail $ mkPatSynCase var ty alt @@ -412,49 +381,6 @@ mkDataConCase var ty alts@(alt1:_) = MatchResult fail_flag mk_case = mkUniqSet data_cons `minusUniqSet` mentioned_constructors exhaustive_case = isEmptyUniqSet un_mentioned_constructors ---- Stuff for parallel arrays --- --- * the following is to desugar cases over fake constructors for --- parallel arrays, which are introduced by `tidy1' in the `PArrPat' --- case --- -mkPArrCase :: DynFlags -> Id -> Type -> [CaseAlt DataCon] -> CoreExpr - -> DsM CoreExpr -mkPArrCase dflags var ty sorted_alts fail = do - lengthP <- dsDPHBuiltin lengthPVar - alt <- unboxAlt - return (mkWildCase (len lengthP) intTy ty [alt]) - where - elemTy = case splitTyConApp (idType var) of - (_, [elemTy]) -> elemTy - _ -> panic panicMsg - panicMsg = "DsUtils.mkCoAlgCaseMatchResult: not a parallel array?" - len lengthP = mkApps (Var lengthP) [Type elemTy, Var var] - -- - unboxAlt = do - l <- newSysLocalDs intPrimTy - indexP <- dsDPHBuiltin indexPVar - alts <- mapM (mkAlt indexP) sorted_alts - return (DataAlt intDataCon, [l], mkWildCase (Var l) intPrimTy ty (dft : alts)) - where - dft = (DEFAULT, [], fail) - - -- - -- each alternative matches one array length (corresponding to one - -- fake array constructor), so the match is on a literal; each - -- alternative's body is extended by a local binding for each - -- constructor argument, which are bound to array elements starting - -- with the first - -- - mkAlt indexP alt@MkCaseAlt{alt_result = MatchResult _ bodyFun} = do - body <- bodyFun fail - return (LitAlt lit, [], mkCoreLets binds body) - where - lit = MachInt $ toInteger (dataConSourceArity (alt_pat alt)) - binds = [NonRec arg (indexExpr i) | (i, arg) <- zip [1..] (alt_bndrs alt)] - -- - indexExpr i = mkApps (Var indexP) [Type elemTy, Var var, mkIntExpr dflags i] - {- ************************************************************************ * * |