X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Frename%2FRnExpr.lhs;h=3b85b3df4d3d4947e1980fd8faf6213c823c8f41;hp=1c80bc0101bb4c28af993991731ced3f96ece765;hb=c24a860db326c7c1c7bab837b62147a984d5aecd;hpb=3a99fa889bdff0c86df20cb18c71d30e30a79b43 diff --git a/compiler/rename/RnExpr.lhs b/compiler/rename/RnExpr.lhs index 1c80bc0..3b85b3d 100644 --- a/compiler/rename/RnExpr.lhs +++ b/compiler/rename/RnExpr.lhs @@ -16,44 +16,61 @@ module RnExpr ( #include "HsVersions.h" +#ifdef GHCI +import {-# SOURCE #-} TcSplice( runQuasiQuoteExpr ) +#endif /* GHCI */ + import RnSource ( rnSrcDecls, rnSplice, checkTH ) -import RnBinds ( rnLocalBindsAndThen, rnValBinds, - rnMatchGroup, trimWith ) +import RnBinds ( rnLocalBindsAndThen, rnValBindsLHS, rnValBindsRHS, + rnMatchGroup, makeMiniFixityEnv) import HsSyn -import RnHsSyn import TcRnMonad import RnEnv -import HscTypes ( availNames ) -import OccName ( plusOccEnv ) -import RnNames ( getLocalDeclBinders, extendRdrEnvRn ) -import RnTypes ( rnHsTypeFVs, rnLPat, rnOverLit, rnPatsAndThen, rnLit, - mkOpFormRn, mkOpAppRn, mkNegAppRn, checkSectionPrec, - dupFieldErr, checkTupSize ) +import RnTypes ( rnHsTypeFVs, + mkOpFormRn, mkOpAppRn, mkNegAppRn, checkSectionPrec) +import RnPat import DynFlags ( DynFlag(..) ) import BasicTypes ( FixityDirection(..) ) -import SrcLoc ( SrcSpan ) import PrelNames ( thFAKE, hasKey, assertIdKey, assertErrorName, loopAName, choiceAName, appAName, arrAName, composeAName, firstAName, - negateName, thenMName, bindMName, failMName ) + negateName, thenMName, bindMName, failMName, groupWithName ) -import Name ( Name, nameOccName, nameIsLocalOrFrom ) +import Name import NameSet -import RdrName ( RdrName, extendLocalRdrEnv, lookupLocalRdrEnv, hideSomeUnquals ) +import RdrName import LoadIface ( loadInterfaceForName ) -import UniqFM ( isNullUFM ) -import UniqSet ( emptyUniqSet ) +import UniqSet import List ( nub ) import Util ( isSingleton ) import ListSetOps ( removeDups ) import Maybes ( expectJust ) import Outputable -import SrcLoc ( Located(..), unLoc, getLoc, cmpLocated ) +import SrcLoc import FastString import List ( unzip4 ) +import Control.Monad \end{code} +\begin{code} +-- XXX +thenM :: Monad a => a b -> (b -> a c) -> a c +thenM = (>>=) + +thenM_ :: Monad a => a b -> a c -> a c +thenM_ = (>>) + +returnM :: Monad m => a -> m a +returnM = return + +mappM :: (Monad m) => (a -> m b) -> [a] -> m [b] +mappM = mapM + +checkM :: Monad m => Bool -> m () -> m () +checkM = unless +\end{code} + %************************************************************************ %* * \subsubsection{Expressions} @@ -73,12 +90,8 @@ rnExprs ls = rnExprs' ls emptyUniqSet let acc' = acc `plusFV` fvExpr in - (grubby_seqNameSet acc' rnExprs') exprs acc' `thenM` \ (exprs', fvExprs) -> + acc' `seq` rnExprs' exprs acc' `thenM` \ (exprs', fvExprs) -> returnM (expr':exprs', fvExprs) - --- Grubby little function to do "seq" on namesets; replace by proper seq when GHC can do seq -grubby_seqNameSet ns result | isNullUFM ns = result - | otherwise = result \end{code} Variables. We look up the variable and return the resulting name. @@ -91,24 +104,30 @@ rnExpr :: HsExpr RdrName -> RnM (HsExpr Name, FreeVars) rnExpr (HsVar v) = do name <- lookupOccRn v - localRdrEnv <- getLocalRdrEnv - lclEnv <- getLclEnv ignore_asserts <- doptM Opt_IgnoreAsserts - ignore_breakpoints <- doptM Opt_IgnoreBreakpoints - ghcMode <- getGhcMode - let conds = [ (name `hasKey` assertIdKey - && not ignore_asserts, - do (e, fvs) <- mkAssertErrorExpr - return (e, fvs `addOneFV` name)) - ] - case lookup True conds of - Just action -> action - Nothing -> return (HsVar name, unitFV name) + finish_var ignore_asserts name + where + finish_var ignore_asserts name + | ignore_asserts || not (name `hasKey` assertIdKey) + = return (HsVar name, unitFV name) + | otherwise + = do { (e, fvs) <- mkAssertErrorExpr + ; return (e, fvs `addOneFV` name) } rnExpr (HsIPVar v) = newIPNameRn v `thenM` \ name -> returnM (HsIPVar name, emptyFVs) +rnExpr (HsLit lit@(HsString s)) + = do { + opt_OverloadedStrings <- doptM Opt_OverloadedStrings + ; if opt_OverloadedStrings then + rnExpr (HsOverLit (mkHsIsString s placeHolderType)) + else -- Same as below + rnLit lit `thenM_` + returnM (HsLit lit, emptyFVs) + } + rnExpr (HsLit lit) = rnLit lit `thenM_` returnM (HsLit lit, emptyFVs) @@ -156,10 +175,20 @@ rnExpr e@(HsBracket br_body) rnBracket br_body `thenM` \ (body', fvs_e) -> returnM (HsBracket body', fvs_e) -rnExpr e@(HsSpliceE splice) +rnExpr (HsSpliceE splice) = rnSplice splice `thenM` \ (splice', fvs) -> returnM (HsSpliceE splice', fvs) +#ifndef GHCI +rnExpr e@(HsQuasiQuoteE _) = pprPanic "Cant do quasiquotation without GHCi" (ppr e) +#else +rnExpr (HsQuasiQuoteE qq) + = rnQuasiQuote qq `thenM` \ (qq', fvs_qq) -> + runQuasiQuoteExpr qq' `thenM` \ (L _ expr') -> + rnExpr expr' `thenM` \ (expr'', fvs_expr) -> + returnM (expr'', fvs_qq `plusFV` fvs_expr) +#endif /* GHCI */ + rnExpr section@(SectionL expr op) = rnLExpr expr `thenM` \ (expr', fvs_expr) -> rnLExpr op `thenM` \ (op', fvs_op) -> @@ -179,6 +208,9 @@ rnExpr (HsCoreAnn ann expr) rnExpr (HsSCC lbl expr) = rnLExpr expr `thenM` \ (expr', fvs_expr) -> returnM (HsSCC lbl expr', fvs_expr) +rnExpr (HsTickPragma info expr) + = rnLExpr expr `thenM` \ (expr', fvs_expr) -> + returnM (HsTickPragma info expr', fvs_expr) rnExpr (HsLam matches) = rnMatchGroup LambdaExpr matches `thenM` \ (matches', fvMatch) -> @@ -194,38 +226,35 @@ rnExpr (HsLet binds expr) rnLExpr expr `thenM` \ (expr',fvExpr) -> returnM (HsLet binds' expr', fvExpr) -rnExpr e@(HsDo do_or_lc stmts body _) +rnExpr (HsDo do_or_lc stmts body _) = do { ((stmts', body'), fvs) <- rnStmts do_or_lc stmts $ rnLExpr body ; return (HsDo do_or_lc stmts' body' placeHolderType, fvs) } rnExpr (ExplicitList _ exps) = rnExprs exps `thenM` \ (exps', fvs) -> - returnM (ExplicitList placeHolderType exps', fvs `addOneFV` listTyCon_name) + returnM (ExplicitList placeHolderType exps', fvs) rnExpr (ExplicitPArr _ exps) = rnExprs exps `thenM` \ (exps', fvs) -> returnM (ExplicitPArr placeHolderType exps', fvs) -rnExpr e@(ExplicitTuple exps boxity) - = checkTupSize tup_size `thenM_` +rnExpr (ExplicitTuple exps boxity) + = checkTupSize (length exps) `thenM_` rnExprs exps `thenM` \ (exps', fvs) -> - returnM (ExplicitTuple exps' boxity, fvs `addOneFV` tycon_name) - where - tup_size = length exps - tycon_name = tupleTyCon_name boxity tup_size + returnM (ExplicitTuple exps' boxity, fvs) rnExpr (RecordCon con_id _ rbinds) - = lookupLocatedOccRn con_id `thenM` \ conname -> - rnRbinds "construction" rbinds `thenM` \ (rbinds', fvRbinds) -> - returnM (RecordCon conname noPostTcExpr rbinds', - fvRbinds `addOneFV` unLoc conname) + = do { conname <- lookupLocatedOccRn con_id + ; (rbinds', fvRbinds) <- rnHsRecFields_Con conname rnLExpr rbinds + ; return (RecordCon conname noPostTcExpr rbinds', + fvRbinds `addOneFV` unLoc conname) } -rnExpr (RecordUpd expr rbinds _ _) - = rnLExpr expr `thenM` \ (expr', fvExpr) -> - rnRbinds "update" rbinds `thenM` \ (rbinds', fvRbinds) -> - returnM (RecordUpd expr' rbinds' placeHolderType placeHolderType, - fvExpr `plusFV` fvRbinds) +rnExpr (RecordUpd expr rbinds _ _ _) + = do { (expr', fvExpr) <- rnLExpr expr + ; (rbinds', fvRbinds) <- rnHsRecFields_Update rnLExpr rbinds + ; return (RecordUpd expr' rbinds' [] [] [], + fvExpr `plusFV` fvRbinds) } rnExpr (ExprWithTySig expr pty) = do { (pty', fvTy) <- rnHsTypeFVs doc pty @@ -263,6 +292,7 @@ We return a (bogus) EWildPat in each case. \begin{code} rnExpr e@EWildPat = patSynErr e rnExpr e@(EAsPat {}) = patSynErr e +rnExpr e@(EViewPat {}) = patSynErr e rnExpr e@(ELazyPat {}) = patSynErr e \end{code} @@ -275,7 +305,7 @@ rnExpr e@(ELazyPat {}) = patSynErr e \begin{code} rnExpr (HsProc pat body) = newArrowScope $ - rnPatsAndThen ProcExpr [pat] $ \ [pat'] -> + rnPatsAndThen_LocalRightwards ProcExpr [pat] $ \ [pat'] -> rnCmdTop body `thenM` \ (body',fvBody) -> returnM (HsProc pat' body', fvBody) @@ -321,13 +351,14 @@ rnExpr other = pprPanic "rnExpr: unexpected expression" (ppr other) %************************************************************************ \begin{code} +rnCmdArgs :: [LHsCmdTop RdrName] -> RnM ([LHsCmdTop Name], FreeVars) rnCmdArgs [] = returnM ([], emptyFVs) rnCmdArgs (arg:args) = rnCmdTop arg `thenM` \ (arg',fvArg) -> rnCmdArgs args `thenM` \ (args',fvArgs) -> returnM (arg':args', fvArg `plusFV` fvArgs) - +rnCmdTop :: LHsCmdTop RdrName -> RnM (LHsCmdTop Name, FreeVars) rnCmdTop = wrapLocFstM rnCmdTop' where rnCmdTop' (HsCmdTop cmd _ _ _) @@ -361,7 +392,6 @@ convertOpFormsCmd (OpApp c1 op fixity c2) convertOpFormsCmd (HsPar c) = HsPar (convertOpFormsLCmd c) --- gaw 2004 convertOpFormsCmd (HsCase exp matches) = HsCase exp (convertOpFormsMatch matches) @@ -380,6 +410,7 @@ convertOpFormsCmd (HsDo ctxt stmts body ty) -- caught by the type checker) convertOpFormsCmd c = c +convertOpFormsStmt :: StmtLR id id -> StmtLR id id convertOpFormsStmt (BindStmt pat cmd _ _) = BindStmt pat (convertOpFormsLCmd cmd) noSyntaxExpr noSyntaxExpr convertOpFormsStmt (ExprStmt cmd _ _) @@ -388,14 +419,17 @@ convertOpFormsStmt (RecStmt stmts lvs rvs es binds) = RecStmt (map (fmap convertOpFormsStmt) stmts) lvs rvs es binds convertOpFormsStmt stmt = stmt +convertOpFormsMatch :: MatchGroup id -> MatchGroup id convertOpFormsMatch (MatchGroup ms ty) = MatchGroup (map (fmap convert) ms) ty where convert (Match pat mty grhss) = Match pat mty (convertOpFormsGRHSs grhss) +convertOpFormsGRHSs :: GRHSs id -> GRHSs id convertOpFormsGRHSs (GRHSs grhss binds) = GRHSs (map convertOpFormsGRHS grhss) binds +convertOpFormsGRHS :: Located (GRHS id) -> Located (GRHS id) convertOpFormsGRHS = fmap convert where convert (GRHS stmts cmd) = GRHS stmts (convertOpFormsLCmd cmd) @@ -410,60 +444,69 @@ methodNamesLCmd = methodNamesCmd . unLoc methodNamesCmd :: HsCmd Name -> CmdNeeds -methodNamesCmd cmd@(HsArrApp _arrow _arg _ HsFirstOrderApp _rtl) +methodNamesCmd (HsArrApp _arrow _arg _ HsFirstOrderApp _rtl) = emptyFVs -methodNamesCmd cmd@(HsArrApp _arrow _arg _ HsHigherOrderApp _rtl) +methodNamesCmd (HsArrApp _arrow _arg _ HsHigherOrderApp _rtl) = unitFV appAName -methodNamesCmd cmd@(HsArrForm {}) = emptyFVs +methodNamesCmd (HsArrForm {}) = emptyFVs methodNamesCmd (HsPar c) = methodNamesLCmd c -methodNamesCmd (HsIf p c1 c2) +methodNamesCmd (HsIf _ c1 c2) = methodNamesLCmd c1 `plusFV` methodNamesLCmd c2 `addOneFV` choiceAName -methodNamesCmd (HsLet b c) = methodNamesLCmd c +methodNamesCmd (HsLet _ c) = methodNamesLCmd c -methodNamesCmd (HsDo sc stmts body ty) +methodNamesCmd (HsDo _ stmts body _) = methodNamesStmts stmts `plusFV` methodNamesLCmd body -methodNamesCmd (HsApp c e) = methodNamesLCmd c +methodNamesCmd (HsApp c _) = methodNamesLCmd c methodNamesCmd (HsLam match) = methodNamesMatch match -methodNamesCmd (HsCase scrut matches) +methodNamesCmd (HsCase _ matches) = methodNamesMatch matches `addOneFV` choiceAName -methodNamesCmd other = emptyFVs +methodNamesCmd _ = emptyFVs -- Other forms can't occur in commands, but it's not convenient -- to error here so we just do what's convenient. -- The type checker will complain later --------------------------------------------------- +methodNamesMatch :: MatchGroup Name -> FreeVars methodNamesMatch (MatchGroup ms _) = plusFVs (map do_one ms) where - do_one (L _ (Match pats sig_ty grhss)) = methodNamesGRHSs grhss + do_one (L _ (Match _ _ grhss)) = methodNamesGRHSs grhss ------------------------------------------------- -- gaw 2004 -methodNamesGRHSs (GRHSs grhss binds) = plusFVs (map methodNamesGRHS grhss) +methodNamesGRHSs :: GRHSs Name -> FreeVars +methodNamesGRHSs (GRHSs grhss _) = plusFVs (map methodNamesGRHS grhss) ------------------------------------------------- -methodNamesGRHS (L _ (GRHS stmts rhs)) = methodNamesLCmd rhs + +methodNamesGRHS :: Located (GRHS Name) -> CmdNeeds +methodNamesGRHS (L _ (GRHS _ rhs)) = methodNamesLCmd rhs --------------------------------------------------- +methodNamesStmts :: [Located (StmtLR Name Name)] -> FreeVars methodNamesStmts stmts = plusFVs (map methodNamesLStmt stmts) --------------------------------------------------- +methodNamesLStmt :: Located (StmtLR Name Name) -> FreeVars methodNamesLStmt = methodNamesStmt . unLoc +methodNamesStmt :: StmtLR Name Name -> FreeVars methodNamesStmt (ExprStmt cmd _ _) = methodNamesLCmd cmd -methodNamesStmt (BindStmt pat cmd _ _) = methodNamesLCmd cmd +methodNamesStmt (BindStmt _ cmd _ _) = methodNamesLCmd cmd methodNamesStmt (RecStmt stmts _ _ _ _) = methodNamesStmts stmts `addOneFV` loopAName -methodNamesStmt (LetStmt b) = emptyFVs -methodNamesStmt (ParStmt ss) = emptyFVs - -- ParStmt can't occur in commands, but it's not convenient to error +methodNamesStmt (LetStmt _) = emptyFVs +methodNamesStmt (ParStmt _) = emptyFVs +methodNamesStmt (TransformStmt _ _ _) = emptyFVs +methodNamesStmt (GroupStmt _ _) = emptyFVs + -- ParStmt, TransformStmt and GroupStmt can't occur in commands, but it's not convenient to error -- here so we just do what's convenient \end{code} @@ -475,6 +518,7 @@ methodNamesStmt (ParStmt ss) = emptyFVs %************************************************************************ \begin{code} +rnArithSeq :: ArithSeqInfo RdrName -> RnM (ArithSeqInfo Name, FreeVars) rnArithSeq (From expr) = rnLExpr expr `thenM` \ (expr', fvExpr) -> returnM (From expr', fvExpr) @@ -497,29 +541,6 @@ rnArithSeq (FromThenTo expr1 expr2 expr3) plusFVs [fvExpr1, fvExpr2, fvExpr3]) \end{code} - -%************************************************************************ -%* * -\subsubsection{@Rbinds@s and @Rpats@s: in record expressions} -%* * -%************************************************************************ - -\begin{code} -rnRbinds str rbinds - = mappM_ field_dup_err dup_fields `thenM_` - mapFvRn rn_rbind rbinds `thenM` \ (rbinds', fvRbind) -> - returnM (rbinds', fvRbind) - where - (_, dup_fields) = removeDups cmpLocated [ f | (f,_) <- rbinds ] - - field_dup_err dups = mappM_ (\f -> addLocErr f (dupFieldErr str)) dups - - rn_rbind (field, expr) - = lookupLocatedGlobalOccRn field `thenM` \ fieldname -> - rnLExpr expr `thenM` \ (expr', fvExpr) -> - returnM ((fieldname, expr'), fvExpr `addOneFV` unLoc fieldname) -\end{code} - %************************************************************************ %* * Template Haskell brackets @@ -527,6 +548,7 @@ rnRbinds str rbinds %************************************************************************ \begin{code} +rnBracket :: HsBracket RdrName -> RnM (HsBracket Name, FreeVars) rnBracket (VarBr n) = do { name <- lookupOccRn n ; this_mod <- getModule ; checkM (nameIsLocalOrFrom this_mod name) $ -- Reason: deprecation checking asumes the @@ -534,50 +556,45 @@ rnBracket (VarBr n) = do { name <- lookupOccRn n ; return () } -- only way that is going to happen ; returnM (VarBr name, unitFV name) } where - msg = ptext SLIT("Need interface for Template Haskell quoted Name") + msg = ptext (sLit "Need interface for Template Haskell quoted Name") rnBracket (ExpBr e) = do { (e', fvs) <- rnLExpr e ; return (ExpBr e', fvs) } -rnBracket (PatBr p) = do { (p', fvs) <- rnLPat p - ; return (PatBr p', fvs) } + +rnBracket (PatBr _) = do { addErr (ptext (sLit "Tempate Haskell pattern brackets are not supported yet")); + failM } + rnBracket (TypBr t) = do { (t', fvs) <- rnHsTypeFVs doc t ; return (TypBr t', fvs) } where - doc = ptext SLIT("In a Template-Haskell quoted type") + doc = ptext (sLit "In a Template-Haskell quoted type") rnBracket (DecBr group) - = do { gbl_env <- getGblEnv - - ; let gbl_env1 = gbl_env { tcg_mod = thFAKE } - -- Note the thFAKE. The top-level names from the bracketed - -- declarations will go into the name cache, and we don't want them to - -- confuse the Names for the current module. - -- By using a pretend module, thFAKE, we keep them safely out of the way. - - ; avails <- getLocalDeclBinders gbl_env1 group - ; let names = concatMap availNames avails + = do { gbl_env <- getGblEnv + + ; let new_gbl_env = gbl_env { -- Set the module to thFAKE. The top-level names from the bracketed + -- declarations will go into the name cache, and we don't want them to + -- confuse the Names for the current module. + -- By using a pretend module, thFAKE, we keep them safely out of the way. + tcg_mod = thFAKE, + + -- The emptyDUs is so that we just collect uses for this group alone + -- in the call to rnSrcDecls below + tcg_dus = emptyDUs } + ; setGblEnv new_gbl_env $ do { - ; let new_occs = map nameOccName names - trimmed_rdr_env = hideSomeUnquals (tcg_rdr_env gbl_env) new_occs - - ; rdr_env' <- extendRdrEnvRn trimmed_rdr_env avails -- In this situation we want to *shadow* top-level bindings. -- foo = 1 - -- bar = [d| foo = 1|] + -- bar = [d| foo = 1 |] -- If we don't shadow, we'll get an ambiguity complaint when we do -- a lookupTopBndrRn (which uses lookupGreLocalRn) on the binder of the 'foo' -- -- Furthermore, arguably if the splice does define foo, that should hide -- any foo's further out -- - -- The shadowing is acheived by the call to hideSomeUnquals, which removes - -- the unqualified bindings of things defined by the bracket - - ; setGblEnv (gbl_env { tcg_rdr_env = rdr_env', - tcg_dus = emptyDUs }) $ do - -- The emptyDUs is so that we just collect uses for this group alone + -- The shadowing is acheived by calling rnSrcDecls with True as the shadowing flag + ; (tcg_env, group') <- rnSrcDecls True group - { (tcg_env, group') <- rnSrcDecls group - -- Discard the tcg_env; it contains only extra info about fixity + -- Discard the tcg_env; it contains only extra info about fixity ; return (DecBr group', allUses (tcg_dus tcg_env)) } } \end{code} @@ -601,21 +618,21 @@ rnNormalStmts :: HsStmtContext Name -> [LStmt RdrName] -- Used for cases *other* than recursive mdo -- Implements nested scopes -rnNormalStmts ctxt [] thing_inside - = do { (thing, fvs) <- thing_inside +rnNormalStmts _ [] thing_inside + = do { (thing, fvs) <- thing_inside ; return (([],thing), fvs) } rnNormalStmts ctxt (L loc stmt : stmts) thing_inside - = do { ((stmt', (stmts', thing)), fvs) - <- rnStmt ctxt stmt $ - rnNormalStmts ctxt stmts thing_inside + = do { ((stmt', (stmts', thing)), fvs) <- rnStmt ctxt stmt $ + rnNormalStmts ctxt stmts thing_inside ; return (((L loc stmt' : stmts'), thing), fvs) } - + + rnStmt :: HsStmtContext Name -> Stmt RdrName -> RnM (thing, FreeVars) -> RnM ((Stmt Name, thing), FreeVars) -rnStmt ctxt (ExprStmt expr _ _) thing_inside +rnStmt _ (ExprStmt expr _ _) thing_inside = do { (expr', fv_expr) <- rnLExpr expr ; (then_op, fvs1) <- lookupSyntaxName thenMName ; (thing, fvs2) <- thing_inside @@ -627,93 +644,174 @@ rnStmt ctxt (BindStmt pat expr _ _) thing_inside -- The binders do not scope over the expression ; (bind_op, fvs1) <- lookupSyntaxName bindMName ; (fail_op, fvs2) <- lookupSyntaxName failMName - ; rnPatsAndThen (StmtCtxt ctxt) [pat] $ \ [pat'] -> do + ; rnPatsAndThen_LocalRightwards (StmtCtxt ctxt) [pat] $ \ [pat'] -> do { (thing, fvs3) <- thing_inside ; return ((BindStmt pat' expr' bind_op fail_op, thing), fv_expr `plusFV` fvs1 `plusFV` fvs2 `plusFV` fvs3) }} - -- fv_expr shouldn't really be filtered by the rnPatsAndThen + -- fv_expr shouldn't really be filtered by the rnPatsAndThen -- but it does not matter because the names are unique -rnStmt ctxt (LetStmt binds) thing_inside - = do { checkErr (ok ctxt binds) - (badIpBinds (ptext SLIT("a parallel list comprehension:")) binds) - ; rnLocalBindsAndThen binds $ \ binds' -> do +rnStmt ctxt (LetStmt binds) thing_inside + = do { checkLetStmt ctxt binds + ; rnLocalBindsAndThen binds $ \binds' -> do { (thing, fvs) <- thing_inside - ; return ((LetStmt binds', thing), fvs) }} - where - -- We do not allow implicit-parameter bindings in a parallel - -- list comprehension. I'm not sure what it might mean. - ok (ParStmtCtxt _) (HsIPBinds _) = False - ok _ _ = True + ; return ((LetStmt binds', thing), fvs) } } rnStmt ctxt (RecStmt rec_stmts _ _ _ _) thing_inside - = bindLocatedLocalsRn doc (collectLStmtsBinders rec_stmts) $ \ bndrs -> - rn_rec_stmts bndrs rec_stmts `thenM` \ segs -> - thing_inside `thenM` \ (thing, fvs) -> - let - segs_w_fwd_refs = addFwdRefs segs - (ds, us, fs, rec_stmts') = unzip4 segs_w_fwd_refs - later_vars = nameSetToList (plusFVs ds `intersectNameSet` fvs) - fwd_vars = nameSetToList (plusFVs fs) - uses = plusFVs us - rec_stmt = RecStmt rec_stmts' later_vars fwd_vars [] emptyLHsBinds - in - returnM ((rec_stmt, thing), uses `plusFV` fvs) - where - doc = text "In a recursive do statement" + = do { checkRecStmt ctxt + ; rn_rec_stmts_and_then rec_stmts $ \ segs -> do + { (thing, fvs) <- thing_inside + ; let + segs_w_fwd_refs = addFwdRefs segs + (ds, us, fs, rec_stmts') = unzip4 segs_w_fwd_refs + later_vars = nameSetToList (plusFVs ds `intersectNameSet` fvs) + fwd_vars = nameSetToList (plusFVs fs) + uses = plusFVs us + rec_stmt = RecStmt rec_stmts' later_vars fwd_vars [] emptyLHsBinds + ; return ((rec_stmt, thing), uses `plusFV` fvs) } } rnStmt ctxt (ParStmt segs) thing_inside - = do { opt_GlasgowExts <- doptM Opt_GlasgowExts - ; checkM opt_GlasgowExts parStmtErr - ; orig_lcl_env <- getLocalRdrEnv - ; ((segs',thing), fvs) <- go orig_lcl_env [] segs + = do { checkParStmt ctxt + ; ((segs', thing), fvs) <- rnParallelStmts (ParStmtCtxt ctxt) segs thing_inside ; return ((ParStmt segs', thing), fvs) } + +rnStmt ctxt (TransformStmt (stmts, _) usingExpr maybeByExpr) thing_inside = do + checkTransformStmt ctxt + + (usingExpr', fv_usingExpr) <- rnLExpr usingExpr + ((stmts', binders, (maybeByExpr', thing)), fvs) <- + rnNormalStmtsAndFindUsedBinders (TransformStmtCtxt ctxt) stmts $ \_unshadowed_bndrs -> do + (maybeByExpr', fv_maybeByExpr) <- rnMaybeLExpr maybeByExpr + (thing, fv_thing) <- thing_inside + + return ((maybeByExpr', thing), fv_maybeByExpr `plusFV` fv_thing) + + return ((TransformStmt (stmts', binders) usingExpr' maybeByExpr', thing), fv_usingExpr `plusFV` fvs) where --- type ParSeg id = [([LStmt id], [id])] --- go :: NameSet -> [ParSeg RdrName] --- -> RnM (([ParSeg Name], thing), FreeVars) - - go orig_lcl_env bndrs [] - = do { let { (bndrs', dups) = removeDups cmpByOcc bndrs - ; inner_env = extendLocalRdrEnv orig_lcl_env bndrs' } - ; mappM dupErr dups - ; (thing, fvs) <- setLocalRdrEnv inner_env thing_inside - ; return (([], thing), fvs) } - - go orig_lcl_env bndrs_so_far ((stmts, _) : segs) - = do { ((stmts', (bndrs, segs', thing)), fvs) - <- rnNormalStmts par_ctxt stmts $ do - { -- Find the Names that are bound by stmts - lcl_env <- getLocalRdrEnv - ; let { rdr_bndrs = collectLStmtsBinders stmts - ; bndrs = map ( expectJust "rnStmt" - . lookupLocalRdrEnv lcl_env - . unLoc) rdr_bndrs - ; new_bndrs = nub bndrs ++ bndrs_so_far - -- The nub is because there might be shadowing - -- x <- e1; x <- e2 - -- So we'll look up (Unqual x) twice, getting - -- the second binding both times, which is the - } -- one we want - - -- Typecheck the thing inside, passing on all - -- the Names bound, but separately; revert the envt - ; ((segs', thing), fvs) <- setLocalRdrEnv orig_lcl_env $ - go orig_lcl_env new_bndrs segs - - -- Figure out which of the bound names are used - ; let used_bndrs = filter (`elemNameSet` fvs) bndrs - ; return ((used_bndrs, segs', thing), fvs) } - - ; let seg' = (stmts', bndrs) - ; return (((seg':segs'), thing), - delListFromNameSet fvs bndrs) } - - par_ctxt = ParStmtCtxt ctxt - - cmpByOcc n1 n2 = nameOccName n1 `compare` nameOccName n2 - dupErr vs = addErr (ptext SLIT("Duplicate binding in parallel list comprehension for:") - <+> quotes (ppr (head vs))) + rnMaybeLExpr Nothing = return (Nothing, emptyFVs) + rnMaybeLExpr (Just expr) = do + (expr', fv_expr) <- rnLExpr expr + return (Just expr', fv_expr) + +rnStmt ctxt (GroupStmt (stmts, _) groupByClause) thing_inside = do + checkTransformStmt ctxt + + -- We must rename the using expression in the context before the transform is begun + groupByClauseAction <- + case groupByClause of + GroupByNothing usingExpr -> do + (usingExpr', fv_usingExpr) <- rnLExpr usingExpr + (return . return) (GroupByNothing usingExpr', fv_usingExpr) + GroupBySomething eitherUsingExpr byExpr -> do + (eitherUsingExpr', fv_eitherUsingExpr) <- + case eitherUsingExpr of + Right _ -> return (Right $ HsVar groupWithName, unitNameSet groupWithName) + Left usingExpr -> do + (usingExpr', fv_usingExpr) <- rnLExpr usingExpr + return (Left usingExpr', fv_usingExpr) + + return $ do + (byExpr', fv_byExpr) <- rnLExpr byExpr + return (GroupBySomething eitherUsingExpr' byExpr', fv_eitherUsingExpr `plusFV` fv_byExpr) + + -- We only use rnNormalStmtsAndFindUsedBinders to get unshadowed_bndrs, so + -- perhaps we could refactor this to use rnNormalStmts directly? + ((stmts', _, (groupByClause', usedBinderMap, thing)), fvs) <- + rnNormalStmtsAndFindUsedBinders (TransformStmtCtxt ctxt) stmts $ \unshadowed_bndrs -> do + (groupByClause', fv_groupByClause) <- groupByClauseAction + + unshadowed_bndrs' <- mapM newLocalName unshadowed_bndrs + let binderMap = zip unshadowed_bndrs unshadowed_bndrs' + + -- Bind the "thing" inside a context where we have REBOUND everything + -- bound by the statements before the group. This is necessary since after + -- the grouping the same identifiers actually have different meanings + -- i.e. they refer to lists not singletons! + (thing, fv_thing) <- bindLocalNames unshadowed_bndrs' thing_inside + + -- We remove entries from the binder map that are not used in the thing_inside. + -- We can then use that usage information to ensure that the free variables do + -- not contain the things we just bound, but do contain the things we need to + -- make those bindings (i.e. the corresponding non-listy variables) + + -- Note that we also retain those entries which have an old binder in our + -- own free variables (the using or by expression). This is because this map + -- is reused in the desugarer to create the type to bind from the statements + -- that occur before this one. If the binders we need are not in the map, they + -- will never get bound into our desugared expression and hence the simplifier + -- crashes as we refer to variables that don't exist! + let usedBinderMap = filter + (\(old_binder, new_binder) -> + (new_binder `elemNameSet` fv_thing) || + (old_binder `elemNameSet` fv_groupByClause)) binderMap + (usedOldBinders, usedNewBinders) = unzip usedBinderMap + real_fv_thing = (delListFromNameSet fv_thing usedNewBinders) `plusFV` (mkNameSet usedOldBinders) + + return ((groupByClause', usedBinderMap, thing), fv_groupByClause `plusFV` real_fv_thing) + + traceRn (text "rnStmt: implicitly rebound these used binders:" <+> ppr usedBinderMap) + return ((GroupStmt (stmts', usedBinderMap) groupByClause', thing), fvs) + +rnNormalStmtsAndFindUsedBinders :: HsStmtContext Name + -> [LStmt RdrName] + -> ([Name] -> RnM (thing, FreeVars)) + -> RnM (([LStmt Name], [Name], thing), FreeVars) +rnNormalStmtsAndFindUsedBinders ctxt stmts thing_inside = do + ((stmts', (used_bndrs, inner_thing)), fvs) <- rnNormalStmts ctxt stmts $ do + -- Find the Names that are bound by stmts that + -- by assumption we have just renamed + local_env <- getLocalRdrEnv + let + stmts_binders = collectLStmtsBinders stmts + bndrs = map (expectJust "rnStmt" + . lookupLocalRdrEnv local_env + . unLoc) stmts_binders + + -- If shadow, we'll look up (Unqual x) twice, getting + -- the second binding both times, which is the + -- one we want + unshadowed_bndrs = nub bndrs + + -- Typecheck the thing inside, passing on all + -- the Names bound before it for its information + (thing, fvs) <- thing_inside unshadowed_bndrs + + -- Figure out which of the bound names are used + -- after the statements we renamed + let used_bndrs = filter (`elemNameSet` fvs) bndrs + return ((used_bndrs, thing), fvs) + + -- Flatten the tuple returned by the above call a bit! + return ((stmts', used_bndrs, inner_thing), fvs) + +rnParallelStmts :: HsStmtContext Name -> [([LStmt RdrName], [RdrName])] + -> RnM (thing, FreeVars) + -> RnM (([([LStmt Name], [Name])], thing), FreeVars) +rnParallelStmts ctxt segs thing_inside = do + orig_lcl_env <- getLocalRdrEnv + go orig_lcl_env [] segs + where + go orig_lcl_env bndrs [] = do + let (bndrs', dups) = removeDups cmpByOcc bndrs + inner_env = extendLocalRdrEnv orig_lcl_env bndrs' + + mappM dupErr dups + (thing, fvs) <- setLocalRdrEnv inner_env thing_inside + return (([], thing), fvs) + + go orig_lcl_env bndrs_so_far ((stmts, _) : segs) = do + ((stmts', bndrs, (segs', thing)), fvs) <- rnNormalStmtsAndFindUsedBinders ctxt stmts $ \new_bndrs -> do + -- Typecheck the thing inside, passing on all + -- the Names bound, but separately; revert the envt + setLocalRdrEnv orig_lcl_env $ do + go orig_lcl_env (new_bndrs ++ bndrs_so_far) segs + + let seg' = (stmts', bndrs) + return (((seg':segs'), thing), delListFromNameSet fvs bndrs) + + cmpByOcc n1 n2 = nameOccName n1 `compare` nameOccName n2 + dupErr vs = addErr (ptext (sLit "Duplicate binding in parallel list comprehension for:") + <+> quotes (ppr (head vs))) \end{code} @@ -734,38 +832,37 @@ type Segment stmts = (Defs, ---------------------------------------------------- + rnMDoStmts :: [LStmt RdrName] -> RnM (thing, FreeVars) -> RnM (([LStmt Name], thing), FreeVars) rnMDoStmts stmts thing_inside - = -- Step1: bring all the binders of the mdo into scope - -- Remember that this also removes the binders from the - -- finally-returned free-vars - bindLocatedLocalsRn doc (collectLStmtsBinders stmts) $ \ bndrs -> - do { - -- Step 2: Rename each individual stmt, making a - -- singleton segment. At this stage the FwdRefs field - -- isn't finished: it's empty for all except a BindStmt - -- for which it's the fwd refs within the bind itself - -- (This set may not be empty, because we're in a recursive - -- context.) - segs <- rn_rec_stmts bndrs stmts + = -- Step1: Bring all the binders of the mdo into scope + -- (Remember that this also removes the binders from the + -- finally-returned free-vars.) + -- And rename each individual stmt, making a + -- singleton segment. At this stage the FwdRefs field + -- isn't finished: it's empty for all except a BindStmt + -- for which it's the fwd refs within the bind itself + -- (This set may not be empty, because we're in a recursive + -- context.) + rn_rec_stmts_and_then stmts $ \ segs -> do { ; (thing, fvs_later) <- thing_inside ; let - -- Step 3: Fill in the fwd refs. + -- Step 2: Fill in the fwd refs. -- The segments are all singletons, but their fwd-ref -- field mentions all the things used by the segment -- that are bound after their use segs_w_fwd_refs = addFwdRefs segs - -- Step 4: Group together the segments to make bigger segments + -- Step 3: Group together the segments to make bigger segments -- Invariant: in the result, no segment uses a variable -- bound in a later segment grouped_segs = glomSegments segs_w_fwd_refs - -- Step 5: Turn the segments into Stmts + -- Step 4: Turn the segments into Stmts -- Use RecStmt when and only when there are fwd refs -- Also gather up the uses from the end towards the -- start, so we can tell the RecStmt which things are @@ -773,29 +870,116 @@ rnMDoStmts stmts thing_inside (stmts', fvs) = segsToStmts grouped_segs fvs_later ; return ((stmts', thing), fvs) } - where - doc = text "In a recursive mdo-expression" --------------------------------------------- -rn_rec_stmts :: [Name] -> [LStmt RdrName] -> RnM [Segment (LStmt Name)] -rn_rec_stmts bndrs stmts = mappM (rn_rec_stmt bndrs) stmts `thenM` \ segs_s -> - returnM (concat segs_s) ----------------------------------------------------- -rn_rec_stmt :: [Name] -> LStmt RdrName -> RnM [Segment (LStmt Name)] +-- wrapper that does both the left- and right-hand sides +rn_rec_stmts_and_then :: [LStmt RdrName] + -- assumes that the FreeVars returned includes + -- the FreeVars of the Segments + -> ([Segment (LStmt Name)] -> RnM (a, FreeVars)) + -> RnM (a, FreeVars) +rn_rec_stmts_and_then s cont + = do { -- (A) Make the mini fixity env for all of the stmts + fix_env <- makeMiniFixityEnv (collectRecStmtsFixities s) + + -- (B) Do the LHSes + ; new_lhs_and_fv <- rn_rec_stmts_lhs fix_env s + + -- ...bring them and their fixities into scope + ; let bound_names = map unLoc $ collectLStmtsBinders (map fst new_lhs_and_fv) + ; bindLocalNamesFV_WithFixities bound_names fix_env $ do + + -- (C) do the right-hand-sides and thing-inside + { segs <- rn_rec_stmts bound_names new_lhs_and_fv + ; (res, fvs) <- cont segs + ; warnUnusedLocalBinds bound_names fvs + ; return (res, fvs) }} + +-- get all the fixity decls in any Let stmt +collectRecStmtsFixities :: [LStmtLR RdrName RdrName] -> [LFixitySig RdrName] +collectRecStmtsFixities l = + foldr (\ s -> \acc -> case s of + (L _ (LetStmt (HsValBinds (ValBindsIn _ sigs)))) -> + foldr (\ sig -> \ acc -> case sig of + (L loc (FixSig s)) -> (L loc s) : acc + _ -> acc) acc sigs + _ -> acc) [] l + +-- left-hand sides + +rn_rec_stmt_lhs :: MiniFixityEnv + -> LStmt RdrName + -- rename LHS, and return its FVs + -- Warning: we will only need the FreeVars below in the case of a BindStmt, + -- so we don't bother to compute it accurately in the other cases + -> RnM [(LStmtLR Name RdrName, FreeVars)] + +rn_rec_stmt_lhs _ (L loc (ExprStmt expr a b)) = return [(L loc (ExprStmt expr a b), + -- this is actually correct + emptyFVs)] + +rn_rec_stmt_lhs fix_env (L loc (BindStmt pat expr a b)) + = do + -- should the ctxt be MDo instead? + (pat', fv_pat) <- rnBindPat (localRecNameMaker fix_env) pat + return [(L loc (BindStmt pat' expr a b), + fv_pat)] + +rn_rec_stmt_lhs _ (L _ (LetStmt binds@(HsIPBinds _))) + = do { addErr (badIpBinds (ptext (sLit "an mdo expression")) binds) + ; failM } + +rn_rec_stmt_lhs fix_env (L loc (LetStmt (HsValBinds binds))) + = do binds' <- rnValBindsLHS fix_env binds + return [(L loc (LetStmt (HsValBinds binds')), + -- Warning: this is bogus; see function invariant + emptyFVs + )] + +rn_rec_stmt_lhs fix_env (L _ (RecStmt stmts _ _ _ _)) -- Flatten Rec inside Rec + = rn_rec_stmts_lhs fix_env stmts + +rn_rec_stmt_lhs _ stmt@(L _ (ParStmt _)) -- Syntactically illegal in mdo + = pprPanic "rn_rec_stmt" (ppr stmt) + +rn_rec_stmt_lhs _ stmt@(L _ (TransformStmt _ _ _)) -- Syntactically illegal in mdo + = pprPanic "rn_rec_stmt" (ppr stmt) + +rn_rec_stmt_lhs _ stmt@(L _ (GroupStmt _ _)) -- Syntactically illegal in mdo + = pprPanic "rn_rec_stmt" (ppr stmt) + +rn_rec_stmt_lhs _ (L _ (LetStmt EmptyLocalBinds)) + = panic "rn_rec_stmt LetStmt EmptyLocalBinds" + +rn_rec_stmts_lhs :: MiniFixityEnv + -> [LStmt RdrName] + -> RnM [(LStmtLR Name RdrName, FreeVars)] +rn_rec_stmts_lhs fix_env stmts = + let boundNames = collectLStmtsBinders stmts + doc = text "In a recursive mdo-expression" + in do + -- First do error checking: we need to check for dups here because we + -- don't bind all of the variables from the Stmt at once + -- with bindLocatedLocals. + checkDupRdrNames doc boundNames + mappM (rn_rec_stmt_lhs fix_env) stmts `thenM` \ ls -> returnM (concat ls) + + +-- right-hand-sides + +rn_rec_stmt :: [Name] -> LStmtLR Name RdrName -> FreeVars -> RnM [Segment (LStmt Name)] -- Rename a Stmt that is inside a RecStmt (or mdo) -- Assumes all binders are already in scope -- Turns each stmt into a singleton Stmt - -rn_rec_stmt all_bndrs (L loc (ExprStmt expr _ _)) - = rnLExpr expr `thenM` \ (expr', fvs) -> +rn_rec_stmt _ (L loc (ExprStmt expr _ _)) _ + = rnLExpr expr `thenM` \ (expr', fvs) -> lookupSyntaxName thenMName `thenM` \ (then_op, fvs1) -> returnM [(emptyNameSet, fvs `plusFV` fvs1, emptyNameSet, L loc (ExprStmt expr' then_op placeHolderType))] -rn_rec_stmt all_bndrs (L loc (BindStmt pat expr _ _)) +rn_rec_stmt _ (L loc (BindStmt pat' expr _ _)) fv_pat = rnLExpr expr `thenM` \ (expr', fv_expr) -> - rnLPat pat `thenM` \ (pat', fv_pat) -> lookupSyntaxName bindMName `thenM` \ (bind_op, fvs1) -> lookupSyntaxName failMName `thenM` \ (fail_op, fvs2) -> let @@ -805,20 +989,36 @@ rn_rec_stmt all_bndrs (L loc (BindStmt pat expr _ _)) returnM [(bndrs, fvs, bndrs `intersectNameSet` fvs, L loc (BindStmt pat' expr' bind_op fail_op))] -rn_rec_stmt all_bndrs (L loc (LetStmt binds@(HsIPBinds _))) - = do { addErr (badIpBinds (ptext SLIT("an mdo expression")) binds) +rn_rec_stmt _ (L _ (LetStmt binds@(HsIPBinds _))) _ + = do { addErr (badIpBinds (ptext (sLit "an mdo expression")) binds) ; failM } -rn_rec_stmt all_bndrs (L loc (LetStmt (HsValBinds binds))) - = rnValBinds (trimWith all_bndrs) binds `thenM` \ (binds', du_binds) -> - returnM [(duDefs du_binds, duUses du_binds, - emptyNameSet, L loc (LetStmt (HsValBinds binds')))] +rn_rec_stmt all_bndrs (L loc (LetStmt (HsValBinds binds'))) _ = do + (binds', du_binds) <- + -- fixities and unused are handled above in rn_rec_stmts_and_then + rnValBindsRHS all_bndrs binds' + returnM [(duDefs du_binds, duUses du_binds, + emptyNameSet, L loc (LetStmt (HsValBinds binds')))] -rn_rec_stmt all_bndrs (L loc (RecStmt stmts _ _ _ _)) -- Flatten Rec inside Rec - = rn_rec_stmts all_bndrs stmts +-- no RecStmt case becuase they get flattened above when doing the LHSes +rn_rec_stmt _ stmt@(L _ (RecStmt _ _ _ _ _)) _ + = pprPanic "rn_rec_stmt: RecStmt" (ppr stmt) -rn_rec_stmt all_bndrs stmt@(L _ (ParStmt _)) -- Syntactically illegal in mdo - = pprPanic "rn_rec_stmt" (ppr stmt) +rn_rec_stmt _ stmt@(L _ (ParStmt _)) _ -- Syntactically illegal in mdo + = pprPanic "rn_rec_stmt: ParStmt" (ppr stmt) + +rn_rec_stmt _ stmt@(L _ (TransformStmt _ _ _)) _ -- Syntactically illegal in mdo + = pprPanic "rn_rec_stmt: TransformStmt" (ppr stmt) + +rn_rec_stmt _ stmt@(L _ (GroupStmt _ _)) _ -- Syntactically illegal in mdo + = pprPanic "rn_rec_stmt: GroupStmt" (ppr stmt) + +rn_rec_stmt _ (L _ (LetStmt EmptyLocalBinds)) _ + = panic "rn_rec_stmt: LetStmt EmptyLocalBinds" + +rn_rec_stmts :: [Name] -> [(LStmtLR Name RdrName, FreeVars)] -> RnM [Segment (LStmt Name)] +rn_rec_stmts bndrs stmts = mappM (uncurry (rn_rec_stmt bndrs)) stmts `thenM` \ segs_s -> + returnM (concat segs_s) --------------------------------------------- addFwdRefs :: [Segment a] -> [Segment a] @@ -949,15 +1149,56 @@ mkAssertErrorExpr %************************************************************************ \begin{code} -patSynErr e = do { addErr (sep [ptext SLIT("Pattern syntax in expression context:"), + +---------------------- +-- Checking when a particular Stmt is ok +checkLetStmt :: HsStmtContext Name -> HsLocalBinds RdrName -> RnM () +checkLetStmt (ParStmtCtxt _) (HsIPBinds binds) = addErr (badIpBinds (ptext (sLit "a parallel list comprehension:")) binds) +checkLetStmt _ctxt _binds = return () + -- We do not allow implicit-parameter bindings in a parallel + -- list comprehension. I'm not sure what it might mean. + +--------- +checkRecStmt :: HsStmtContext Name -> RnM () +checkRecStmt (MDoExpr {}) = return () -- Recursive stmt ok in 'mdo' +checkRecStmt (DoExpr {}) = return () -- ..and in 'do' but only because of arrows: + -- proc x -> do { ...rec... } + -- We don't have enough context to distinguish this situation here + -- so we leave it to the type checker +checkRecStmt ctxt = addErr msg + where + msg = ptext (sLit "Illegal 'rec' stmt in") <+> pprStmtContext ctxt + +--------- +checkParStmt :: HsStmtContext Name -> RnM () +checkParStmt _ + = do { parallel_list_comp <- doptM Opt_ParallelListComp + ; checkErr parallel_list_comp msg } + where + msg = ptext (sLit "Illegal parallel list comprehension: use -XParallelListComp") + +--------- +checkTransformStmt :: HsStmtContext Name -> RnM () +checkTransformStmt ListComp -- Ensure we are really within a list comprehension because otherwise the + -- desugarer will break when we come to operate on a parallel array + = do { transform_list_comp <- doptM Opt_TransformListComp + ; checkErr transform_list_comp msg } + where + msg = ptext (sLit "Illegal transform or grouping list comprehension: use -XTransformListComp") +checkTransformStmt (ParStmtCtxt ctxt) = checkTransformStmt ctxt -- Ok to nest inside a parallel comprehension +checkTransformStmt (TransformStmtCtxt ctxt) = checkTransformStmt ctxt -- Ok to nest inside a parallel comprehension +checkTransformStmt ctxt = addErr msg + where + msg = ptext (sLit "Illegal transform or grouping in") <+> pprStmtContext ctxt + +--------- +patSynErr :: HsExpr RdrName -> RnM (HsExpr Name, FreeVars) +patSynErr e = do { addErr (sep [ptext (sLit "Pattern syntax in expression context:"), nest 4 (ppr e)]) ; return (EWildPat, emptyFVs) } -parStmtErr = addErr (ptext SLIT("Illegal parallel list comprehension: use -fglasgow-exts")) - +badIpBinds :: Outputable a => SDoc -> a -> SDoc badIpBinds what binds - = hang (ptext SLIT("Implicit-parameter bindings illegal in") <+> what) + = hang (ptext (sLit "Implicit-parameter bindings illegal in") <+> what) 2 (ppr binds) \end{code} - -