X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2FdeSugar%2FCheck.lhs;h=9aac5ce777c04309f4d34bfc7982b5544c3a0bc8;hb=5d3051c66796dcf884b052f9e4afc3ed19b9f514;hp=d1ae572578c04ce53c537ac9c216d2902a403967;hpb=550421384b8364cdaf3135f7859c9f7d7ee1fff1;p=ghc-hetmet.git diff --git a/ghc/compiler/deSugar/Check.lhs b/ghc/compiler/deSugar/Check.lhs index d1ae572..9aac5ce 100644 --- a/ghc/compiler/deSugar/Check.lhs +++ b/ghc/compiler/deSugar/Check.lhs @@ -11,19 +11,20 @@ module Check ( check , ExhaustivePat ) where import HsSyn -import TcHsSyn ( hsPatType ) +import TcHsSyn ( hsPatType, mkVanillaTuplePat ) import TcType ( tcTyConAppTyCon ) -import DsUtils ( EquationInfo(..), MatchResult(..), EqnSet, - CanItFail(..), tidyLitPat, tidyNPat, - ) +import DsUtils ( EquationInfo(..), MatchResult(..), + CanItFail(..), firstPat ) +import MatchLit ( tidyLitPat, tidyNPat ) import Id ( Id, idType ) import DataCon ( DataCon, dataConTyCon, dataConOrigArgTys, dataConFieldLabels ) -import Name ( Name, mkInternalName, getOccName, isDataSymOcc, getName, mkVarOcc ) +import Name ( Name, mkInternalName, getOccName, isDataSymOcc, + getName, mkVarOccFS ) import TysWiredIn import PrelNames ( unboundKey ) import TyCon ( tyConDataCons, tupleTyConBoxity, isTupleTyCon ) import BasicTypes ( Boxity(..) ) -import SrcLoc ( noSrcLoc, Located(..), getLoc, unLoc, noLoc ) +import SrcLoc ( noSrcLoc, Located(..), unLoc, noLoc ) import UniqSet import Util ( takeList, splitAtList, notNull ) import Outputable @@ -96,17 +97,22 @@ Then we need to use InPats. Juan Quintela 5 JUL 1998\\ User-friendliness and compiler writers are no friends. \end{quotation} -\begin{code} +\begin{code} type WarningPat = InPat Name type ExhaustivePat = ([WarningPat], [(Name, [HsLit])]) +type EqnNo = Int +type EqnSet = UniqSet EqnNo -check :: [EquationInfo] -> ([ExhaustivePat],EqnSet) -check qs = (untidy_warns, incomplete) +check :: [EquationInfo] -> ([ExhaustivePat], [EquationInfo]) + -- Second result is the shadowed equations +check qs = (untidy_warns, shadowed_eqns) where - (warns, incomplete) = check' (simplify_eqns qs) + (warns, used_nos) = check' ([1..] `zip` map simplify_eqn qs) untidy_warns = map untidy_exhaustive warns + shadowed_eqns = [eqn | (eqn,i) <- qs `zip` [1..], + not (i `elementOfUniqSet` used_nos)] untidy_exhaustive :: ExhaustivePat -> ExhaustivePat untidy_exhaustive ([pat], messages) = @@ -139,9 +145,9 @@ untidy b (L loc p) = L loc (untidy' b p) untidy' _ p@(ConPatIn name (PrefixCon [])) = p untidy' b (ConPatIn name ps) = pars b (L loc (ConPatIn name (untidy_con ps))) untidy' _ (ListPat pats ty) = ListPat (map untidy_no_pars pats) ty - untidy' _ (TuplePat pats boxed) = TuplePat (map untidy_no_pars pats) boxed + untidy' _ (TuplePat pats box ty) = TuplePat (map untidy_no_pars pats) box ty untidy' _ (PArrPat _ _) = panic "Check.untidy: Shouldn't get a parallel array here!" - untidy' _ (SigPatIn _ _) = panic "Check.untidy: SigPat" + untidy' _ (SigPatIn _ _) = panic "Check.untidy: SigPat" untidy_con (PrefixCon pats) = PrefixCon (map untidy_pars pats) untidy_con (InfixCon p1 p2) = InfixCon (untidy_pars p1) (untidy_pars p2) @@ -184,21 +190,26 @@ There are several cases: \begin{code} -check' :: [EquationInfo] -> ([ExhaustivePat],EqnSet) -check' [] = ([([],[])],emptyUniqSet) +check' :: [(EqnNo, EquationInfo)] + -> ([ExhaustivePat], -- Pattern scheme that might not be matched at all + EqnSet) -- Eqns that are used (others are overlapped) + +check' [] = ([([],[])],emptyUniqSet) + +check' ((n, EqnInfo { eqn_pats = ps, eqn_rhs = MatchResult can_fail _ }) : rs) + | first_eqn_all_vars && case can_fail of { CantFail -> True; CanFail -> False } + = ([], unitUniqSet n) -- One eqn, which can't fail -check' [EqnInfo n ctx ps (MatchResult CanFail _)] - | all_vars ps = ([(takeList ps (repeat wildPat),[])], unitUniqSet n) + | first_eqn_all_vars && null rs -- One eqn, but it can fail + = ([(takeList ps (repeat nlWildPat),[])], unitUniqSet n) -check' qs@((EqnInfo n ctx ps (MatchResult CanFail _)):rs) - | all_vars ps = (pats, addOneToUniqSet indexs n) + | first_eqn_all_vars -- Several eqns, first can fail + = (pats, addOneToUniqSet indexs n) where + first_eqn_all_vars = all_vars ps (pats,indexs) = check' rs -check' qs@((EqnInfo n ctx ps result):_) - | all_vars ps = ([], unitUniqSet n) --- | nplusk = panic "Check.check': Work in progress: nplusk" --- | npat = panic "Check.check': Work in progress: npat ?????" +check' qs | literals = split_by_literals qs | constructors = split_by_constructor qs | only_vars = first_column_only_vars qs @@ -206,12 +217,10 @@ check' qs@((EqnInfo n ctx ps result):_) where -- Note: RecPats will have been simplified to ConPats -- at this stage. - first_pats = ASSERT2( okGroup qs, pprGroup qs ) map firstPat qs + first_pats = ASSERT2( okGroup qs, pprGroup qs ) map firstPatN qs constructors = any is_con first_pats literals = any is_lit first_pats only_vars = all is_var first_pats --- npat = or (map is_npat qs) --- nplusk = or (map is_nplusk qs) \end{code} Here begins the code to deal with literals, we need to split the matrix @@ -219,7 +228,7 @@ in different matrix beginning by each literal and a last matrix with the rest of values. \begin{code} -split_by_literals :: [EquationInfo] -> ([ExhaustivePat],EqnSet) +split_by_literals :: [(EqnNo, EquationInfo)] -> ([ExhaustivePat], EqnSet) split_by_literals qs = process_literals used_lits qs where used_lits = get_used_lits qs @@ -229,12 +238,11 @@ split_by_literals qs = process_literals used_lits qs in the column of the matrix. \begin{code} -process_explicit_literals :: [HsLit] -> [EquationInfo] -> ([ExhaustivePat],EqnSet) +process_explicit_literals :: [HsLit] -> [(EqnNo, EquationInfo)] -> ([ExhaustivePat],EqnSet) process_explicit_literals lits qs = (concat pats, unionManyUniqSets indexs) where pats_indexs = map (\x -> construct_literal_matrix x qs) lits (pats,indexs) = unzip pats_indexs - \end{code} @@ -244,16 +252,16 @@ must be one Variable to be complete. \begin{code} -process_literals :: [HsLit] -> [EquationInfo] -> ([ExhaustivePat],EqnSet) +process_literals :: [HsLit] -> [(EqnNo, EquationInfo)] -> ([ExhaustivePat],EqnSet) process_literals used_lits qs - | null default_eqns = ([make_row_vars used_lits (head qs)]++pats,indexs) + | null default_eqns = ([make_row_vars used_lits (head qs)] ++ pats,indexs) | otherwise = (pats_default,indexs_default) where (pats,indexs) = process_explicit_literals used_lits qs default_eqns = ASSERT2( okGroup qs, pprGroup qs ) - map remove_var (filter (is_var . firstPat) qs) + [remove_var q | q <- qs, is_var (firstPatN q)] (pats',indexs') = check' default_eqns - pats_default = [(wildPat:ps,constraints) | (ps,constraints) <- (pats')] ++ pats + pats_default = [(nlWildPat:ps,constraints) | (ps,constraints) <- (pats')] ++ pats indexs_default = unionUniqSets indexs' indexs \end{code} @@ -261,7 +269,7 @@ Here we have selected the literal and we will select all the equations that begins for that literal and create a new matrix. \begin{code} -construct_literal_matrix :: HsLit -> [EquationInfo] -> ([ExhaustivePat],EqnSet) +construct_literal_matrix :: HsLit -> [(EqnNo, EquationInfo)] -> ([ExhaustivePat],EqnSet) construct_literal_matrix lit qs = (map (\ (xs,ys) -> (new_lit:xs,ys)) pats,indexs) where @@ -269,42 +277,37 @@ construct_literal_matrix lit qs = new_lit = nlLitPat lit remove_first_column_lit :: HsLit - -> [EquationInfo] - -> [EquationInfo] + -> [(EqnNo, EquationInfo)] + -> [(EqnNo, EquationInfo)] remove_first_column_lit lit qs = ASSERT2( okGroup qs, pprGroup qs ) - map shift_pat (filter (is_var_lit lit . firstPat) qs) + [(n, shift_pat eqn) | q@(n,eqn) <- qs, is_var_lit lit (firstPatN q)] where - shift_pat (EqnInfo n ctx [] result) = panic "Check.shift_var: no patterns" - shift_pat (EqnInfo n ctx (_:ps) result) = EqnInfo n ctx ps result - + shift_pat eqn@(EqnInfo { eqn_pats = _:ps}) = eqn { eqn_pats = ps } + shift_pat eqn@(EqnInfo { eqn_pats = []}) = panic "Check.shift_var: no patterns" \end{code} This function splits the equations @qs@ in groups that deal with the same constructor. \begin{code} - -split_by_constructor :: [EquationInfo] -> ([ExhaustivePat],EqnSet) - +split_by_constructor :: [(EqnNo, EquationInfo)] -> ([ExhaustivePat], EqnSet) split_by_constructor qs | notNull unused_cons = need_default_case used_cons unused_cons qs | otherwise = no_need_default_case used_cons qs where used_cons = get_used_cons qs unused_cons = get_unused_cons used_cons - \end{code} The first column of the patterns matrix only have vars, then there is nothing to do. \begin{code} -first_column_only_vars :: [EquationInfo] -> ([ExhaustivePat],EqnSet) -first_column_only_vars qs = (map (\ (xs,ys) -> (wildPat:xs,ys)) pats,indexs) +first_column_only_vars :: [(EqnNo, EquationInfo)] -> ([ExhaustivePat],EqnSet) +first_column_only_vars qs = (map (\ (xs,ys) -> (nlWildPat:xs,ys)) pats,indexs) where - (pats,indexs) = check' (map remove_var qs) - + (pats, indexs) = check' (map remove_var qs) \end{code} This equation takes a matrix of patterns and split the equations by @@ -316,19 +319,20 @@ constructors or not explicitly. The reasoning is similar to @process_literals@, the difference is that here the default case is not always needed. \begin{code} -no_need_default_case :: [Pat Id] -> [EquationInfo] -> ([ExhaustivePat],EqnSet) +no_need_default_case :: [Pat Id] -> [(EqnNo, EquationInfo)] -> ([ExhaustivePat],EqnSet) no_need_default_case cons qs = (concat pats, unionManyUniqSets indexs) where pats_indexs = map (\x -> construct_matrix x qs) cons (pats,indexs) = unzip pats_indexs -need_default_case :: [Pat Id] -> [DataCon] -> [EquationInfo] -> ([ExhaustivePat],EqnSet) +need_default_case :: [Pat Id] -> [DataCon] -> [(EqnNo, EquationInfo)] -> ([ExhaustivePat],EqnSet) need_default_case used_cons unused_cons qs | null default_eqns = (pats_default_no_eqns,indexs) | otherwise = (pats_default,indexs_default) where (pats,indexs) = no_need_default_case used_cons qs - default_eqns = ASSERT2( okGroup qs, pprGroup qs ) map remove_var (filter (is_var . firstPat) qs) + default_eqns = ASSERT2( okGroup qs, pprGroup qs ) + [remove_var q | q <- qs, is_var (firstPatN q)] (pats',indexs') = check' default_eqns pats_default = [(make_whole_con c:ps,constraints) | c <- unused_cons, (ps,constraints) <- pats'] ++ pats @@ -336,7 +340,7 @@ need_default_case used_cons unused_cons qs pats_default_no_eqns = [(make_whole_con c:new_wilds,[]) | c <- unused_cons] ++ pats indexs_default = unionUniqSets indexs' indexs -construct_matrix :: Pat Id -> [EquationInfo] -> ([ExhaustivePat],EqnSet) +construct_matrix :: Pat Id -> [(EqnNo, EquationInfo)] -> ([ExhaustivePat],EqnSet) construct_matrix con qs = (map (make_con con) pats,indexs) where @@ -359,41 +363,47 @@ is transformed in: \begin{code} remove_first_column :: Pat Id -- Constructor - -> [EquationInfo] - -> [EquationInfo] -remove_first_column (ConPatOut con (PrefixCon con_pats) _ _ _) qs + -> [(EqnNo, EquationInfo)] + -> [(EqnNo, EquationInfo)] +remove_first_column (ConPatOut (L _ con) _ _ _ (PrefixCon con_pats) _) qs = ASSERT2( okGroup qs, pprGroup qs ) - map shift_var (filter (is_var_con con . firstPat) qs) + [(n, shift_var eqn) | q@(n, eqn) <- qs, is_var_con con (firstPatN q)] where new_wilds = [WildPat (hsPatType arg_pat) | arg_pat <- con_pats] - shift_var (EqnInfo n ctx (ConPatOut _ (PrefixCon ps') _ _ _:ps) result) = - EqnInfo n ctx (map unLoc ps'++ps) result - shift_var (EqnInfo n ctx (WildPat _ :ps) result) = - EqnInfo n ctx (new_wilds ++ ps) result + shift_var eqn@(EqnInfo { eqn_pats = ConPatOut _ _ _ _ (PrefixCon ps') _ : ps}) + = eqn { eqn_pats = map unLoc ps' ++ ps } + shift_var eqn@(EqnInfo { eqn_pats = WildPat _ : ps }) + = eqn { eqn_pats = new_wilds ++ ps } shift_var _ = panic "Check.Shift_var:No done" -make_row_vars :: [HsLit] -> EquationInfo -> ExhaustivePat -make_row_vars used_lits (EqnInfo _ _ pats _ ) = - (nlVarPat new_var:takeList (tail pats) (repeat wildPat),[(new_var,used_lits)]) - where new_var = hash_x +make_row_vars :: [HsLit] -> (EqnNo, EquationInfo) -> ExhaustivePat +make_row_vars used_lits (_, EqnInfo { eqn_pats = pats}) + = (nlVarPat new_var:takeList (tail pats) (repeat nlWildPat),[(new_var,used_lits)]) + where + new_var = hash_x hash_x = mkInternalName unboundKey {- doesn't matter much -} - (mkVarOcc FSLIT("#x")) + (mkVarOccFS FSLIT("#x")) noSrcLoc -make_row_vars_for_constructor :: EquationInfo -> [WarningPat] -make_row_vars_for_constructor (EqnInfo _ _ pats _ ) = takeList (tail pats) (repeat wildPat) +make_row_vars_for_constructor :: (EqnNo, EquationInfo) -> [WarningPat] +make_row_vars_for_constructor (_, EqnInfo { eqn_pats = pats}) + = takeList (tail pats) (repeat nlWildPat) compare_cons :: Pat Id -> Pat Id -> Bool -compare_cons (ConPatOut id1 _ _ _ _) (ConPatOut id2 _ _ _ _) = id1 == id2 +compare_cons (ConPatOut (L _ id1) _ _ _ _ _) (ConPatOut (L _ id2) _ _ _ _ _) = id1 == id2 remove_dups :: [Pat Id] -> [Pat Id] remove_dups [] = [] remove_dups (x:xs) | or (map (\y -> compare_cons x y) xs) = remove_dups xs | otherwise = x : remove_dups xs -get_used_cons :: [EquationInfo] -> [Pat Id] -get_used_cons qs = remove_dups [con | (EqnInfo _ _ (con@(ConPatOut _ _ _ _ _):_) _) <- qs ] +get_used_cons :: [(EqnNo, EquationInfo)] -> [Pat Id] +get_used_cons qs = remove_dups [pat | q <- qs, let pat = firstPatN q, + isConPatOut pat] + +isConPatOut (ConPatOut {}) = True +isConPatOut other = False remove_dups' :: [HsLit] -> [HsLit] remove_dups' [] = [] @@ -401,27 +411,37 @@ remove_dups' (x:xs) | x `elem` xs = remove_dups' xs | otherwise = x : remove_dups' xs -get_used_lits :: [EquationInfo] -> [HsLit] +get_used_lits :: [(EqnNo, EquationInfo)] -> [HsLit] get_used_lits qs = remove_dups' all_literals where all_literals = get_used_lits' qs -get_used_lits' :: [EquationInfo] -> [HsLit] +get_used_lits' :: [(EqnNo, EquationInfo)] -> [HsLit] get_used_lits' [] = [] -get_used_lits' ((EqnInfo _ _ ((LitPat lit):_) _):qs) = - lit : get_used_lits qs -get_used_lits' ((EqnInfo _ _ ((NPatOut lit _ _):_) _):qs) = - lit : get_used_lits qs -get_used_lits' (q:qs) = - get_used_lits qs +get_used_lits' (q:qs) + | Just lit <- get_lit (firstPatN q) = lit : get_used_lits' qs + | otherwise = get_used_lits qs + +get_lit :: Pat id -> Maybe HsLit +-- Get a representative HsLit to stand for the OverLit +-- It doesn't matter which one, because they will only be compared +-- with other HsLits gotten in the same way +get_lit (LitPat lit) = Just lit +get_lit (NPat (HsIntegral i _) mb _ _) = Just (HsIntPrim (mb_neg mb i)) +get_lit (NPat (HsFractional f _) mb _ _) = Just (HsFloatPrim (mb_neg mb f)) +get_lit other_pat = Nothing + +mb_neg :: Num a => Maybe b -> a -> a +mb_neg Nothing v = v +mb_neg (Just _) v = -v get_unused_cons :: [Pat Id] -> [DataCon] get_unused_cons used_cons = unused_cons where - (ConPatOut _ _ ty _ _) = head used_cons + (ConPatOut _ _ _ _ _ ty) = head used_cons ty_con = tcTyConAppTyCon ty -- Newtype observable all_cons = tyConDataCons ty_con - used_cons_as_id = map (\ (ConPatOut d _ _ _ _) -> d) used_cons + used_cons_as_id = map (\ (ConPatOut (L _ d) _ _ _ _ _) -> d) used_cons unused_cons = uniqSetToList (mkUniqSet all_cons `minusUniqSet` mkUniqSet used_cons_as_id) @@ -430,19 +450,15 @@ all_vars [] = True all_vars (WildPat _:ps) = all_vars ps all_vars _ = False -remove_var :: EquationInfo -> EquationInfo -remove_var (EqnInfo n ctx (WildPat _:ps) result) = EqnInfo n ctx ps result -remove_var _ = - panic "Check.remove_var: equation does not begin with a variable" +remove_var :: (EqnNo, EquationInfo) -> (EqnNo, EquationInfo) +remove_var (n, eqn@(EqnInfo { eqn_pats = WildPat _ : ps})) = (n, eqn { eqn_pats = ps }) +remove_var _ = panic "Check.remove_var: equation does not begin with a variable" ----------------------- -eqnPats :: EquationInfo -> [Pat Id] -eqnPats (EqnInfo _ _ ps _) = ps - -firstPat :: EquationInfo -> Pat Id -firstPat eqn_info = head (eqnPats eqn_info) +eqnPats :: (EqnNo, EquationInfo) -> [Pat Id] +eqnPats (_, eqn) = eqn_pats eqn -okGroup :: [EquationInfo] -> Bool +okGroup :: [(EqnNo, EquationInfo)] -> Bool -- True if all equations have at least one pattern, and -- all have the same number of patterns okGroup [] = True @@ -454,37 +470,33 @@ okGroup (e:es) = n_pats > 0 && and [length (eqnPats e) == n_pats | e <- es] pprGroup es = vcat (map pprEqnInfo es) pprEqnInfo e = ppr (eqnPats e) + +firstPatN :: (EqnNo, EquationInfo) -> Pat Id +firstPatN (_, eqn) = firstPat eqn + is_con :: Pat Id -> Bool -is_con (ConPatOut _ _ _ _ _) = True +is_con (ConPatOut _ _ _ _ _ _) = True is_con _ = False is_lit :: Pat Id -> Bool is_lit (LitPat _) = True -is_lit (NPatOut _ _ _) = True +is_lit (NPat _ _ _ _) = True is_lit _ = False -is_npat :: Pat Id -> Bool -is_npat (NPatOut _ _ _) = True -is_npat _ = False - -is_nplusk :: Pat Id -> Bool -is_nplusk (NPlusKPatOut _ _ _ _) = True -is_nplusk _ = False - is_var :: Pat Id -> Bool is_var (WildPat _) = True is_var _ = False is_var_con :: DataCon -> Pat Id -> Bool -is_var_con con (WildPat _) = True -is_var_con con (ConPatOut id _ _ _ _) | id == con = True -is_var_con con _ = False +is_var_con con (WildPat _) = True +is_var_con con (ConPatOut (L _ id) _ _ _ _ _) | id == con = True +is_var_con con _ = False is_var_lit :: HsLit -> Pat Id -> Bool -is_var_lit lit (WildPat _) = True -is_var_lit lit (LitPat lit') | lit == lit' = True -is_var_lit lit (NPatOut lit' _ _) | lit == lit' = True -is_var_lit lit _ = False +is_var_lit lit (WildPat _) = True +is_var_lit lit pat + | Just lit' <- get_lit pat = lit == lit' + | otherwise = False \end{code} The difference beteewn @make_con@ and @make_whole_con@ is that @@ -540,15 +552,14 @@ make_list p (ListPat ps ty) = ListPat (p:ps) ty make_list _ _ = panic "Check.make_list: Invalid argument" make_con :: Pat Id -> ExhaustivePat -> ExhaustivePat -make_con (ConPatOut id _ _ _ _) (lp:lq:ps, constraints) +make_con (ConPatOut (L _ id) _ _ _ _ _) (lp:lq:ps, constraints) | return_list id q = (noLoc (make_list lp q) : ps, constraints) | isInfixCon id = (nlInfixConPat (getName id) lp lq : ps, constraints) - where p = unLoc lp - q = unLoc lq + where q = unLoc lq -make_con (ConPatOut id (PrefixCon pats) _ _ _) (ps, constraints) - | isTupleTyCon tc = (noLoc (TuplePat pats_con (tupleTyConBoxity tc)) : rest_pats, constraints) - | isPArrFakeCon id = (noLoc (PArrPat pats_con placeHolderType) : rest_pats, constraints) +make_con (ConPatOut (L _ id) _ _ _ (PrefixCon pats) ty) (ps, constraints) + | isTupleTyCon tc = (noLoc (TuplePat pats_con (tupleTyConBoxity tc) ty) : rest_pats, constraints) + | isPArrFakeCon id = (noLoc (PArrPat pats_con placeHolderType) : rest_pats, constraints) | otherwise = (nlConPat name pats_con : rest_pats, constraints) where name = getName id @@ -557,16 +568,16 @@ make_con (ConPatOut id (PrefixCon pats) _ _ _) (ps, constraints) -- reconstruct parallel array pattern -- --- * don't check for the type only; we need to make sure that we are really +-- * don't check for the type only; we need to make sure that we are really -- dealing with one of the fake constructors and not with the real -- representation make_whole_con :: DataCon -> WarningPat -make_whole_con con | isInfixCon con = nlInfixConPat name wildPat wildPat +make_whole_con con | isInfixCon con = nlInfixConPat name nlWildPat nlWildPat | otherwise = nlConPat name pats where name = getName con - pats = [wildPat | t <- dataConOrigArgTys con] + pats = [nlWildPat | t <- dataConOrigArgTys con] \end{code} This equation makes the same thing as @tidy@ in @Match.lhs@, the @@ -576,12 +587,33 @@ constraints. \begin{code} -simplify_eqns :: [EquationInfo] -> [EquationInfo] -simplify_eqns [] = [] -simplify_eqns ((EqnInfo n ctx pats result):qs) = - (EqnInfo n ctx pats' result) : simplify_eqns qs - where - pats' = map simplify_pat pats +simplify_eqn :: EquationInfo -> EquationInfo +simplify_eqn eqn = eqn { eqn_pats = map simplify_pat (eqn_pats eqn), + eqn_rhs = simplify_rhs (eqn_rhs eqn) } + where + -- Horrible hack. The simplify_pat stuff converts NPlusK pats to WildPats + -- which of course loses the info that they can fail to match. So we + -- stick in a CanFail as if it were a guard. + -- The Right Thing to do is for the whole system to treat NPlusK pats properly + simplify_rhs (MatchResult can_fail body) + | any has_nplusk_pat (eqn_pats eqn) = MatchResult CanFail body + | otherwise = MatchResult can_fail body + +has_nplusk_lpat :: LPat Id -> Bool +has_nplusk_lpat (L _ p) = has_nplusk_pat p + +has_nplusk_pat :: Pat Id -> Bool +has_nplusk_pat (NPlusKPat _ _ _ _) = True +has_nplusk_pat (ParPat p) = has_nplusk_lpat p +has_nplusk_pat (AsPat _ p) = has_nplusk_lpat p +has_nplusk_pat (SigPatOut p _ ) = has_nplusk_lpat p +has_nplusk_pat (ConPatOut _ _ _ _ ps ty) = any has_nplusk_lpat (hsConArgs ps) +has_nplusk_pat (ListPat ps _) = any has_nplusk_lpat ps +has_nplusk_pat (TuplePat ps _ _) = any has_nplusk_lpat ps +has_nplusk_pat (PArrPat ps _) = any has_nplusk_lpat ps +has_nplusk_pat (LazyPat p) = False -- Why? +has_nplusk_pat (BangPat p) = has_nplusk_lpat p -- I think +has_nplusk_pat p = False -- VarPat, VarPatOut, WildPat, LitPat, NPat, TypePat, DictPat simplify_lpat :: LPat Id -> LPat Id simplify_lpat p = fmap simplify_pat p @@ -589,13 +621,15 @@ simplify_lpat p = fmap simplify_pat p simplify_pat :: Pat Id -> Pat Id simplify_pat pat@(WildPat gt) = pat simplify_pat (VarPat id) = WildPat (idType id) +simplify_pat (VarPatOut id _) = WildPat (idType id) -- Ignore the bindings +simplify_pat (ParPat p) = unLoc (simplify_lpat p) +simplify_pat (LazyPat p) = unLoc (simplify_lpat p) +simplify_pat (BangPat p) = unLoc (simplify_lpat p) +simplify_pat (AsPat id p) = unLoc (simplify_lpat p) +simplify_pat (SigPatOut p _) = unLoc (simplify_lpat p) -- I'm not sure this is right -simplify_pat (ParPat p) = unLoc (simplify_lpat p) -simplify_pat (LazyPat p) = unLoc (simplify_lpat p) -simplify_pat (AsPat id p) = unLoc (simplify_lpat p) -simplify_pat (SigPatOut p ty fn) = unLoc (simplify_lpat p) -- I'm not sure this is right - -simplify_pat (ConPatOut id ps ty tvs dicts) = ConPatOut id (simplify_con id ps) ty tvs dicts +simplify_pat (ConPatOut (L loc id) tvs dicts binds ps ty) + = ConPatOut (L loc id) tvs dicts binds (simplify_con id ps) ty simplify_pat (ListPat ps ty) = unLoc $ foldr (\ x y -> mkPrefixConPat consDataCon [x,y] list_ty) @@ -607,56 +641,53 @@ simplify_pat (ListPat ps ty) = -- arrays with the existing machinery for constructor pattern -- simplify_pat (PArrPat ps ty) - = ConPatOut (parrFakeCon arity) - (PrefixCon (map simplify_lpat ps)) - (mkPArrTy ty) [] [] + = mk_simple_con_pat (parrFakeCon (length ps)) + (PrefixCon (map simplify_lpat ps)) + (mkPArrTy ty) + +simplify_pat (TuplePat ps boxity ty) + = mk_simple_con_pat (tupleCon boxity arity) + (PrefixCon (map simplify_lpat ps)) + ty where arity = length ps -simplify_pat (TuplePat ps boxity) - = ConPatOut (tupleCon boxity arity) - (PrefixCon (map simplify_lpat ps)) - (mkTupleTy boxity arity (map hsPatType ps)) [] [] - where - arity = length ps - -simplify_pat pat@(LitPat lit) = unLoc (tidyLitPat lit (noLoc pat)) - -- unpack string patterns fully, so we can see when they overlap with -- each other, or even explicit lists of Chars. -simplify_pat pat@(NPatOut (HsString s) _ _) = - foldr (\c pat -> ConPatOut consDataCon (PrefixCon [mk_char_lit c,noLoc pat]) stringTy [] []) - (ConPatOut nilDataCon (PrefixCon []) stringTy [] []) (unpackFS s) +simplify_pat pat@(LitPat (HsString s)) = + foldr (\c pat -> mk_simple_con_pat consDataCon (PrefixCon [mk_char_lit c,noLoc pat]) stringTy) + (mk_simple_con_pat nilDataCon (PrefixCon []) stringTy) (unpackFS s) where - mk_char_lit c = noLoc $ - ConPatOut charDataCon (PrefixCon [nlLitPat (HsCharPrim c)]) - charTy [] [] + mk_char_lit c = noLoc (mk_simple_con_pat charDataCon (PrefixCon [nlLitPat (HsCharPrim c)]) charTy) -simplify_pat pat@(NPatOut lit lit_ty hsexpr) = unLoc (tidyNPat lit lit_ty (noLoc pat)) +simplify_pat pat@(LitPat lit) = unLoc (tidyLitPat lit (noLoc pat)) + +simplify_pat pat@(NPat lit mb_neg _ lit_ty) = unLoc (tidyNPat lit mb_neg lit_ty (noLoc pat)) -simplify_pat (NPlusKPatOut id hslit hsexpr1 hsexpr2) +simplify_pat (NPlusKPat id hslit hsexpr1 hsexpr2) = WildPat (idType (unLoc id)) simplify_pat (DictPat dicts methods) = case num_of_d_and_ms of - 0 -> simplify_pat (TuplePat [] Boxed) + 0 -> simplify_pat (TuplePat [] Boxed unitTy) 1 -> simplify_pat (head dict_and_method_pats) - _ -> simplify_pat (TuplePat (map noLoc dict_and_method_pats) Boxed) + _ -> simplify_pat (mkVanillaTuplePat (map noLoc dict_and_method_pats) Boxed) where num_of_d_and_ms = length dicts + length methods dict_and_method_pats = map VarPat (dicts ++ methods) +mk_simple_con_pat con args ty = ConPatOut (noLoc con) [] [] emptyLHsBinds args ty + ----------------- simplify_con con (PrefixCon ps) = PrefixCon (map simplify_lpat ps) simplify_con con (InfixCon p1 p2) = PrefixCon [simplify_lpat p1, simplify_lpat p2] simplify_con con (RecCon fs) - | null fs = PrefixCon [wildPat | t <- dataConOrigArgTys con] + | null fs = PrefixCon [nlWildPat | t <- dataConOrigArgTys con] -- Special case for null patterns; maybe not a record at all | otherwise = PrefixCon (map (simplify_lpat.snd) all_pats) where -- pad out all the missing fields with WildPats. - field_pats = map (\ f -> (getName f, wildPat)) - (dataConFieldLabels con) + field_pats = map (\ f -> (f, nlWildPat)) (dataConFieldLabels con) all_pats = foldr (\ (id,p) acc -> insertNm (getName (unLoc id)) p acc) field_pats fs