X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2FhsSyn%2FHsPat.lhs;h=3efcd59ecf514354e6ad137633ff439d768472c1;hb=478e69b303eb2e653a2ebf5c888b5efdfef1fb9d;hp=c025a8dc35627b0619d0a9cef24a5b0643a82358;hpb=f278f0676579f67075033a4f9857715909c4b71e;p=ghc-hetmet.git diff --git a/compiler/hsSyn/HsPat.lhs b/compiler/hsSyn/HsPat.lhs index c025a8d..3efcd59 100644 --- a/compiler/hsSyn/HsPat.lhs +++ b/compiler/hsSyn/HsPat.lhs @@ -20,11 +20,11 @@ module HsPat ( HsConPatDetails, hsConPatArgs, HsRecFields(..), HsRecField(..), hsRecFields, - mkPrefixConPat, mkCharLitPat, mkNilPat, mkCoPat, mkCoPatCoI, + mkPrefixConPat, mkCharLitPat, mkNilPat, - isBangHsBind, hsPatNeedsParens, - patsAreAllCons, isConPat, isSigPat, isWildPat, - patsAreAllLits, isLitPat, isIrrefutableHsPat, + isBangHsBind, isLiftedPatBind, + isBangLPat, hsPatNeedsParens, + isIrrefutableHsPat, pprParendLPat ) where @@ -37,7 +37,6 @@ import HsLit import HsTypes import BasicTypes -- others: -import Coercion import PprCore ( {- instance OutputableBndr TyVar -} ) import TysWiredIn import Var @@ -49,6 +48,7 @@ import SrcLoc import FastString -- libraries: import Data.Data hiding (TyCon) +import Data.Maybe \end{code} @@ -65,8 +65,6 @@ data Pat id -- support hsPatType :: Pat Id -> Type | VarPat id -- Variable - | VarPatOut id (DictBinds id) -- Used only for overloaded Ids; the - -- bindings give its overloaded instances | LazyPat (LPat id) -- Lazy pattern | AsPat (Located id) (LPat id) -- As pattern | ParPat (LPat id) -- Parenthesised pattern @@ -101,10 +99,10 @@ data Pat id | ConPatOut { pat_con :: Located DataCon, pat_tvs :: [TyVar], -- Existentially bound type variables (tyvars only) - pat_dicts :: [id], -- Ditto *coercion variables* and *dictionaries* + pat_dicts :: [EvVar], -- Ditto *coercion variables* and *dictionaries* -- One reason for putting coercion variable here, I think, -- is to ensure their kinds are zonked - pat_binds :: DictBinds id, -- Bindings involving those dictionaries + pat_binds :: TcEvBinds, -- Bindings involving those dictionaries pat_args :: HsConPatDetails id, pat_ty :: Type -- The type of the pattern } @@ -124,7 +122,9 @@ data Pat id | LitPat HsLit -- Used for *non-overloaded* literal patterns: -- Int#, Char#, Int, Char, String, etc. - | NPat (HsOverLit id) -- ALWAYS positive + | NPat -- Used for all overloaded literals, + -- including overloaded strings with -XOverloadedStrings + (HsOverLit id) -- ALWAYS positive (Maybe (SyntaxExpr id)) -- Just (Name of 'negate') for negative -- patterns, Nothing otherwise (SyntaxExpr id) -- Equality checker, of type t->t->Bool @@ -148,7 +148,7 @@ data Pat id Type ------------ Pattern coercions (translation only) --------------- - | CoPat HsWrapper -- If co::t1 -> t2, p::t2, + | CoPat HsWrapper -- If co :: t1 ~ t2, p :: t2, -- then (CoPat co p) :: t1 (Pat id) -- Why not LPat? Ans: existing locn will do Type -- Type of whole pattern, t1 @@ -258,7 +258,6 @@ patNeedsParens _ = False pprPat :: (OutputableBndr name) => Pat name -> SDoc pprPat (VarPat var) = pprPatBndr var -pprPat (VarPatOut var bs) = pprPatBndr var <+> braces (ppr bs) pprPat (WildPat _) = char '_' pprPat (LazyPat pat) = char '~' <> pprParendLPat pat pprPat (BangPat pat) = char '!' <> pprParendLPat pat @@ -276,7 +275,7 @@ pprPat (ConPatOut { pat_con = con, pat_tvs = tvs, pat_dicts = dicts, if debugStyle sty then -- typechecked Pat in an error message, -- and we want to make sure it prints nicely ppr con <+> sep [ hsep (map pprPatBndr tvs) <+> hsep (map pprPatBndr dicts), - pprLHsBinds binds, pprConArgs details] + ppr binds, pprConArgs details] else pprUserCon con details pprPat (LitPat s) = ppr s @@ -331,7 +330,7 @@ mkPrefixConPat :: DataCon -> [OutPat id] -> Type -> OutPat id -- Make a vanilla Prefix constructor pattern mkPrefixConPat dc pats ty = noLoc $ ConPatOut { pat_con = noLoc dc, pat_tvs = [], pat_dicts = [], - pat_binds = emptyLHsBinds, pat_args = PrefixCon pats, + pat_binds = emptyTcEvBinds, pat_args = PrefixCon pats, pat_ty = ty } mkNilPat :: Type -> OutPat id @@ -339,15 +338,6 @@ mkNilPat ty = mkPrefixConPat nilDataCon [] ty mkCharLitPat :: Char -> OutPat id mkCharLitPat c = mkPrefixConPat charDataCon [noLoc $ LitPat (HsCharPrim c)] charTy - -mkCoPat :: HsWrapper -> Pat id -> Type -> Pat id -mkCoPat co pat ty - | isIdHsWrapper co = pat - | otherwise = CoPat co pat ty - -mkCoPatCoI :: CoercionI -> Pat id -> Type -> Pat id -mkCoPatCoI IdCo pat _ = pat -mkCoPatCoI (ACo co) pat ty = mkCoPat (WpCast co) pat ty \end{code} @@ -381,41 +371,34 @@ patterns are treated specially, of course. The 1.3 report defines what ``irrefutable'' and ``failure-free'' patterns are. \begin{code} -isWildPat :: Pat id -> Bool -isWildPat (WildPat _) = True -isWildPat _ = False - -patsAreAllCons :: [Pat id] -> Bool -patsAreAllCons pat_list = all isConPat pat_list - -isConPat :: Pat id -> Bool -isConPat (AsPat _ pat) = isConPat (unLoc pat) -isConPat (ConPatIn {}) = True -isConPat (ConPatOut {}) = True -isConPat (ListPat {}) = True -isConPat (PArrPat {}) = True -isConPat (TuplePat {}) = True -isConPat _ = False - -isSigPat :: Pat id -> Bool -isSigPat (SigPatIn _ _) = True -isSigPat (SigPatOut _ _) = True -isSigPat _ = False - -patsAreAllLits :: [Pat id] -> Bool -patsAreAllLits pat_list = all isLitPat pat_list - -isLitPat :: Pat id -> Bool -isLitPat (AsPat _ pat) = isLitPat (unLoc pat) -isLitPat (LitPat _) = True -isLitPat (NPat _ _ _) = True -isLitPat (NPlusKPat _ _ _ _) = True -isLitPat _ = False +isBangLPat :: LPat id -> Bool +isBangLPat (L _ (BangPat {})) = True +isBangLPat (L _ (ParPat p)) = isBangLPat p +isBangLPat _ = False isBangHsBind :: HsBind id -> Bool --- In this module because HsPat is above HsBinds in the import graph -isBangHsBind (PatBind { pat_lhs = L _ (BangPat _) }) = True -isBangHsBind _ = False +-- A pattern binding with an outermost bang +-- Defined in this module because HsPat is above HsBinds in the import graph +isBangHsBind (PatBind { pat_lhs = p }) = isBangLPat p +isBangHsBind _ = False + +isLiftedPatBind :: HsBind id -> Bool +-- A pattern binding with a compound pattern, not just a variable +-- (I# x) yes +-- (# a, b #) no, even if a::Int# +-- x no, even if x::Int# +-- We want to warn about a missing bang-pattern on the yes's +isLiftedPatBind (PatBind { pat_lhs = p }) = isLiftedLPat p +isLiftedPatBind _ = False + +isLiftedLPat :: LPat id -> Bool +isLiftedLPat (L _ (ParPat p)) = isLiftedLPat p +isLiftedLPat (L _ (BangPat p)) = isLiftedLPat p +isLiftedLPat (L _ (AsPat _ p)) = isLiftedLPat p +isLiftedLPat (L _ (TuplePat _ Unboxed _)) = False +isLiftedLPat (L _ (VarPat {})) = False +isLiftedLPat (L _ (WildPat {})) = False +isLiftedLPat _ = True isIrrefutableHsPat :: OutputableBndr id => LPat id -> Bool -- (isIrrefutableHsPat p) is true if matching against p cannot fail, @@ -433,7 +416,6 @@ isIrrefutableHsPat pat go1 (WildPat {}) = True go1 (VarPat {}) = True - go1 (VarPatOut {}) = True go1 (LazyPat {}) = True go1 (BangPat pat) = go pat go1 (CoPat _ pat _) = go1 pat @@ -448,7 +430,9 @@ isIrrefutableHsPat pat go1 (ConPatIn {}) = False -- Conservative go1 (ConPatOut{ pat_con = L _ con, pat_args = details }) - = isProductTyCon (dataConTyCon con) + = isJust (tyConSingleDataCon_maybe (dataConTyCon con)) + -- NB: tyConSingleDataCon_maybe, *not* isProductTyCon, because + -- the latter is false of existentials. See Trac #4439 && all go (hsConPatArgs details) go1 (LitPat {}) = False @@ -464,7 +448,6 @@ isIrrefutableHsPat pat hsPatNeedsParens :: Pat a -> Bool hsPatNeedsParens (WildPat {}) = False hsPatNeedsParens (VarPat {}) = False -hsPatNeedsParens (VarPatOut {}) = True hsPatNeedsParens (LazyPat {}) = False hsPatNeedsParens (BangPat {}) = False hsPatNeedsParens (CoPat {}) = True