X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Frename%2FRnExpr.lhs;h=103badca9e9758e02e212ee9a4b2c5c4e25250d5;hb=174dccda5a8213f9a777ddf5230effef6b5f464d;hp=d9b229dd34ffb941bb794947b07cf2083e7a95f1;hpb=6a05ec5ef5373f61b7f9f5bdc344483417fa801b;p=ghc-hetmet.git diff --git a/compiler/rename/RnExpr.lhs b/compiler/rename/RnExpr.lhs index d9b229d..103badc 100644 --- a/compiler/rename/RnExpr.lhs +++ b/compiler/rename/RnExpr.lhs @@ -10,58 +10,68 @@ general, all of these functions return a renamed thing, and a set of free variables. \begin{code} -{-# OPTIONS -w #-} --- The above warning supression flag is a temporary kludge. --- While working on this module you are encouraged to remove it and fix --- any warnings in the module. See --- http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings --- for details - module RnExpr ( rnLExpr, rnExpr, rnStmts ) where #include "HsVersions.h" +#ifdef GHCI +import {-# SOURCE #-} TcSplice( runQuasiQuoteExpr ) +#endif /* GHCI */ + import RnSource ( rnSrcDecls, rnSplice, checkTH ) import RnBinds ( rnLocalBindsAndThen, rnValBindsLHS, rnValBindsRHS, rnMatchGroup, makeMiniFixityEnv) import HsSyn import TcRnMonad +import TcEnv ( thRnBrack ) import RnEnv -import HscTypes ( availNames ) -import RnNames ( getLocalDeclBinders, extendRdrEnvRn ) import RnTypes ( rnHsTypeFVs, mkOpFormRn, mkOpAppRn, mkNegAppRn, checkSectionPrec) -import RnPat (rnOverLit, rnPatsAndThen_LocalRightwards, rnPat_LocalRec, localNameMaker, - rnLit, - rnHsRecFields_Con, rnHsRecFields_Update, checkTupSize) +import RnPat import DynFlags ( DynFlag(..) ) import BasicTypes ( FixityDirection(..) ) -import SrcLoc ( SrcSpan ) -import PrelNames ( thFAKE, hasKey, assertIdKey, assertErrorName, +import PrelNames ( 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 UniqFM -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 ) +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} @@ -81,12 +91,8 @@ 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. @@ -97,17 +103,20 @@ rnLExpr = wrapLocFstM rnExpr rnExpr :: HsExpr RdrName -> RnM (HsExpr Name, FreeVars) +finishHsVar :: Name -> RnM (HsExpr Name, FreeVars) +-- Separated from rnExpr because it's also used +-- when renaming infix expressions +-- See Note [Adding the implicit parameter to 'assert'] +finishHsVar name + = do { ignore_asserts <- doptM Opt_IgnoreAsserts + ; if ignore_asserts || not (name `hasKey` assertIdKey) + then return (HsVar name, unitFV name) + else do { e <- mkAssertErrorExpr + ; return (e, unitFV name) } } + rnExpr (HsVar v) - = do name <- lookupOccRn v - ignore_asserts <- doptM Opt_IgnoreAsserts - 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) } + = do name <- lookupOccRn v + finishHsVar name rnExpr (HsIPVar v) = newIPNameRn v `thenM` \ name -> @@ -136,21 +145,21 @@ rnExpr (HsApp fun arg) rnLExpr arg `thenM` \ (arg',fvArg) -> returnM (HsApp fun' arg', fvFun `plusFV` fvArg) -rnExpr (OpApp e1 op _ e2) - = rnLExpr e1 `thenM` \ (e1', fv_e1) -> - rnLExpr e2 `thenM` \ (e2', fv_e2) -> - rnLExpr op `thenM` \ (op'@(L _ (HsVar op_name)), fv_op) -> - +rnExpr (OpApp e1 (L op_loc (HsVar op_rdr)) _ e2) + = do { (e1', fv_e1) <- rnLExpr e1 + ; (e2', fv_e2) <- rnLExpr e2 + ; op_name <- setSrcSpan op_loc (lookupOccRn op_rdr) + ; (op', fv_op) <- finishHsVar op_name + -- NB: op' is usually just a variable, but might be + -- an applicatoin (assert "Foo.hs:47") -- Deal with fixity -- When renaming code synthesised from "deriving" declarations -- we used to avoid fixity stuff, but we can't easily tell any -- more, so I've removed the test. Adding HsPars in TcGenDeriv -- should prevent bad things happening. - lookupFixityRn op_name `thenM` \ fixity -> - mkOpAppRn e1' op' fixity e2' `thenM` \ final_e -> - - returnM (final_e, - fv_e1 `plusFV` fv_op `plusFV` fv_e2) + ; fixity <- lookupFixityRn op_name + ; final_e <- mkOpAppRn e1' (L op_loc op') fixity e2' + ; return (final_e, fv_e1 `plusFV` fv_op `plusFV` fv_e2) } rnExpr (NegApp e _) = rnLExpr e `thenM` \ (e', fv_e) -> @@ -158,10 +167,7 @@ rnExpr (NegApp e _) mkNegAppRn e' neg_name `thenM` \ final_e -> returnM (final_e, fv_e `plusFV` fv_neg) -rnExpr (HsPar e) - = rnLExpr e `thenM` \ (e', fvs_e) -> - returnM (HsPar e', fvs_e) - +------------------------------------------ -- Template Haskell extensions -- Don't ifdef-GHCI them because we want to fail gracefully -- (not with an rnExpr crash) in a stage-1 compiler. @@ -170,22 +176,41 @@ 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) -rnExpr section@(SectionL expr op) - = rnLExpr expr `thenM` \ (expr', fvs_expr) -> - rnLExpr op `thenM` \ (op', fvs_op) -> - checkSectionPrec InfixL section op' expr' `thenM_` - returnM (SectionL expr' op', fvs_op `plusFV` fvs_expr) +#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@(SectionR op expr) - = rnLExpr op `thenM` \ (op', fvs_op) -> - rnLExpr expr `thenM` \ (expr', fvs_expr) -> - checkSectionPrec InfixR section op' expr' `thenM_` - returnM (SectionR op' expr', fvs_op `plusFV` fvs_expr) +--------------------------------------------- +-- Sections +-- See Note [Parsing sections] in Parser.y.pp +rnExpr (HsPar (L loc (section@(SectionL {})))) + = do { (section', fvs) <- rnSection section + ; return (HsPar (L loc section'), fvs) } + +rnExpr (HsPar (L loc (section@(SectionR {})))) + = do { (section', fvs) <- rnSection section + ; return (HsPar (L loc section'), fvs) } + +rnExpr (HsPar e) + = do { (e', fvs_e) <- rnLExpr e + ; return (HsPar e', fvs_e) } + +rnExpr expr@(SectionL {}) + = do { addErr (sectionErr expr); rnSection expr } +rnExpr expr@(SectionR {}) + = do { addErr (sectionErr expr); rnSection expr } +--------------------------------------------- rnExpr (HsCoreAnn ann expr) = rnLExpr expr `thenM` \ (expr', fvs_expr) -> returnM (HsCoreAnn ann expr', fvs_expr) @@ -211,7 +236,7 @@ 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) } @@ -224,7 +249,7 @@ rnExpr (ExplicitPArr _ exps) = rnExprs exps `thenM` \ (exps', fvs) -> returnM (ExplicitPArr placeHolderType exps', fvs) -rnExpr e@(ExplicitTuple exps boxity) +rnExpr (ExplicitTuple exps boxity) = checkTupSize (length exps) `thenM_` rnExprs exps `thenM` \ (exps', fvs) -> returnM (ExplicitTuple exps' boxity, fvs) @@ -277,6 +302,7 @@ 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} @@ -289,7 +315,7 @@ rnExpr e@(ELazyPat {}) = patSynErr e \begin{code} rnExpr (HsProc pat body) = newArrowScope $ - rnPatsAndThen_LocalRightwards ProcExpr [pat] $ \ ([pat'],_) -> + rnPatsAndThen_LocalRightwards ProcExpr [pat] $ \ [pat'] -> rnCmdTop body `thenM` \ (body',fvBody) -> returnM (HsProc pat' body', fvBody) @@ -325,8 +351,24 @@ rnExpr (HsArrForm op fixity cmds) rnExpr other = pprPanic "rnExpr: unexpected expression" (ppr other) -- HsWrap -\end{code} +---------------------- +-- See Note [Parsing sections] in Parser.y.pp +rnSection :: HsExpr RdrName -> RnM (HsExpr Name, FreeVars) +rnSection section@(SectionR op expr) + = do { (op', fvs_op) <- rnLExpr op + ; (expr', fvs_expr) <- rnLExpr expr + ; checkSectionPrec InfixR section op' expr' + ; return (SectionR op' expr', fvs_op `plusFV` fvs_expr) } + +rnSection section@(SectionL expr op) + = do { (expr', fvs_expr) <- rnLExpr expr + ; (op', fvs_op) <- rnLExpr op + ; checkSectionPrec InfixL section op' expr' + ; return (SectionL expr' op', fvs_op `plusFV` fvs_expr) } + +rnSection other = pprPanic "rnSection" (ppr other) +\end{code} %************************************************************************ %* * @@ -335,13 +377,14 @@ 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 _ _ _) @@ -375,7 +418,6 @@ convertOpFormsCmd (OpApp c1 op fixity c2) convertOpFormsCmd (HsPar c) = HsPar (convertOpFormsLCmd c) --- gaw 2004 convertOpFormsCmd (HsCase exp matches) = HsCase exp (convertOpFormsMatch matches) @@ -394,6 +436,7 @@ 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 _ _) @@ -402,14 +445,17 @@ 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) @@ -424,60 +470,69 @@ 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} @@ -489,6 +544,7 @@ 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) @@ -518,6 +574,7 @@ rnArithSeq (FromThenTo expr1 expr2 expr3) %************************************************************************ \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 @@ -525,46 +582,28 @@ 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 { addErr (ptext SLIT("Tempate Haskell pattern brackets are not supported yet")); - failM } - +rnBracket (PatBr _) = failWith (ptext (sLit "Tempate Haskell pattern brackets are not supported yet")) 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 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 { - - -- In this situation we want to *shadow* top-level bindings. - -- 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 calling rnSrcDecls with True as the shadowing flag - ; (tcg_env, group') <- rnSrcDecls True group + ; let new_gbl_env = gbl_env { tcg_dus = emptyDUs } + -- The emptyDUs is so that we just collect uses for this + -- group alone in the call to rnSrcDecls below + ; (tcg_env, group') <- setGblEnv new_gbl_env $ + setStage thRnBrack $ + rnSrcDecls group -- Discard the tcg_env; it contains only extra info about fixity - ; return (DecBr group', allUses (tcg_dus tcg_env)) } } + ; return (DecBr group', allUses (tcg_dus tcg_env)) } \end{code} %************************************************************************ @@ -587,14 +626,13 @@ 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) } @@ -602,7 +640,7 @@ 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 @@ -614,93 +652,174 @@ 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_LocalRightwards (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 -- 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 - = - rn_rec_stmts_and_then rec_stmts $ \ 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 { parallel_list_comp <- doptM Opt_ParallelListComp - ; checkM parallel_list_comp 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} @@ -759,8 +878,6 @@ rnMDoStmts stmts thing_inside (stmts', fvs) = segsToStmts grouped_segs fvs_later ; return ((stmts', thing), fvs) } - where - doc = text "In a recursive mdo-expression" --------------------------------------------- @@ -770,33 +887,28 @@ rn_rec_stmts_and_then :: [LStmt RdrName] -- 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 +rn_rec_stmts_and_then s cont + = do { -- (A) Make the mini fixity env for all of the stmts + fix_env <- makeMiniFixityEnv (collectRecStmtsFixities 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 + -- (B) Do the LHSes + ; new_lhs_and_fv <- rn_rec_stmts_lhs fix_env s - -- (C) do the right-hand-sides and thing-inside - segs <- rn_rec_stmts bound_names new_lhs_and_fv - (result, result_fvs) <- cont segs - - -- (D) warn about unusued binders - let unused_bndrs = [ b | b <- bound_names, not (b `elemNameSet` result_fvs)] - warnUnusedLocalBinds unused_bndrs - - -- (E) return - return (result, result_fvs) + -- ...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 loc (LetStmt (HsValBinds (ValBindsIn _ sigs)))) -> + (L _ (LetStmt (HsValBinds (ValBindsIn _ sigs)))) -> foldr (\ sig -> \ acc -> case sig of (L loc (FixSig s)) -> (L loc s) : acc _ -> acc) acc sigs @@ -804,28 +916,26 @@ collectRecStmtsFixities l = -- left-hand sides -rn_rec_stmt_lhs :: UniqFM (Located Fixity) -- mini fixity env for the names we're about to bind - -- these fixities need to be brought into scope with the names +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 fix_env (L loc (ExprStmt expr a b)) = return [(L loc (ExprStmt expr a b), +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) <- rnPat_LocalRec fix_env pat + (pat', fv_pat) <- rnBindPat (localRecNameMaker fix_env) pat return [(L loc (BindStmt pat' expr a b), fv_pat)] -rn_rec_stmt_lhs fix_env (L loc (LetStmt binds@(HsIPBinds _))) - = do { addErr (badIpBinds (ptext SLIT("an mdo expression")) binds) - ; failM } +rn_rec_stmt_lhs _ (L _ (LetStmt binds@(HsIPBinds _))) + = failWith (badIpBinds (ptext (sLit "an mdo expression")) binds) rn_rec_stmt_lhs fix_env (L loc (LetStmt (HsValBinds binds))) = do binds' <- rnValBindsLHS fix_env binds @@ -834,14 +944,22 @@ rn_rec_stmt_lhs fix_env (L loc (LetStmt (HsValBinds binds))) emptyFVs )] -rn_rec_stmt_lhs fix_env (L loc (RecStmt stmts _ _ _ _)) -- Flatten Rec inside Rec +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 :: UniqFM (Located Fixity) -- mini fixity env for the names we're about to bind - -- these fixities need to be brought into scope with the names +rn_rec_stmts_lhs :: MiniFixityEnv -> [LStmt RdrName] -> RnM [(LStmtLR Name RdrName, FreeVars)] rn_rec_stmts_lhs fix_env stmts = @@ -851,7 +969,7 @@ rn_rec_stmts_lhs fix_env stmts = -- 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. - checkDupNames doc boundNames + checkDupRdrNames doc boundNames mappM (rn_rec_stmt_lhs fix_env) stmts `thenM` \ ls -> returnM (concat ls) @@ -861,13 +979,13 @@ rn_rec_stmt :: [Name] -> LStmtLR Name RdrName -> FreeVars -> RnM [Segment (LStmt -- 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 _ _)) _ +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 _ _)) fv_pat +rn_rec_stmt _ (L loc (BindStmt pat' expr _ _)) fv_pat = rnLExpr expr `thenM` \ (expr', fv_expr) -> lookupSyntaxName bindMName `thenM` \ (bind_op, fvs1) -> lookupSyntaxName failMName `thenM` \ (fail_op, fvs2) -> @@ -878,24 +996,32 @@ rn_rec_stmt all_bndrs (L loc (BindStmt pat' expr _ _)) fv_pat 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) - ; failM } +rn_rec_stmt _ (L _ (LetStmt binds@(HsIPBinds _))) _ + = failWith (badIpBinds (ptext (sLit "an mdo expression")) 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' + rnValBindsRHS (mkNameSet all_bndrs) binds' returnM [(duDefs du_binds, duUses du_binds, emptyNameSet, L loc (LetStmt (HsValBinds binds')))] -- no RecStmt case becuase they get flattened above when doing the LHSes -rn_rec_stmt all_bndrs stmt@(L loc (RecStmt stmts _ _ _ _)) _ +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 +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) @@ -1009,19 +1135,26 @@ segsToStmts ((defs, uses, fwds, ss) : segs) fvs_later \begin{code} srcSpanPrimLit :: SrcSpan -> HsExpr Name -srcSpanPrimLit span = HsLit (HsStringPrim (mkFastString (showSDoc (ppr span)))) +srcSpanPrimLit span = HsLit (HsStringPrim (mkFastString (showSDocOneLine (ppr span)))) -mkAssertErrorExpr :: RnM (HsExpr Name, FreeVars) +mkAssertErrorExpr :: RnM (HsExpr Name) -- Return an expression for (assertError "Foo.hs:27") mkAssertErrorExpr = getSrcSpanM `thenM` \ sloc -> - let - expr = HsApp (L sloc (HsVar assertErrorName)) - (L sloc (srcSpanPrimLit sloc)) - in - returnM (expr, emptyFVs) + return (HsApp (L sloc (HsVar assertErrorName)) + (L sloc (srcSpanPrimLit sloc))) \end{code} +Note [Adding the implicit parameter to 'assert'] +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +The renamer transforms (assert e1 e2) to (assert "Foo.hs:27" e1 e2). +By doing this in the renamer we allow the typechecker to just see the +expanded application and do the right thing. But it's not really +the Right Thing because there's no way to "undo" if you want to see +the original source code. We'll have fix this in due course, when +we care more about being able to reconstruct the exact original +program. + %************************************************************************ %* * \subsubsection{Errors} @@ -1029,15 +1162,61 @@ 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 + +--------- +sectionErr :: HsExpr RdrName -> SDoc +sectionErr expr + = hang (ptext (sLit "A section must be enclosed in parentheses")) + 2 (ptext (sLit "thus:") <+> (parens (ppr expr))) + +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 -XParallelListComp")) - +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} - -