import {-# SOURCE #-} TcSplice( runQuasiQuoteExpr )
#endif /* GHCI */
-import RnSource ( rnSrcDecls, rnSplice, checkTH )
-import RnBinds ( rnLocalBindsAndThen, rnValBindsLHS, rnValBindsRHS,
+import RnSource ( rnSrcDecls, findSplice )
+import RnBinds ( rnLocalBindsAndThen, rnLocalValBindsLHS, rnLocalValBindsRHS,
rnMatchGroup, makeMiniFixityEnv)
import HsSyn
import TcRnMonad
import TcEnv ( thRnBrack )
import RnEnv
-import RnTypes ( rnHsTypeFVs,
+import RnTypes ( rnHsTypeFVs, rnSplice, checkTH,
mkOpFormRn, mkOpAppRn, mkNegAppRn, checkSectionPrec)
import RnPat
-import DynFlags ( DynFlag(..) )
+import DynFlags
import BasicTypes ( FixityDirection(..) )
-import PrelNames ( hasKey, assertIdKey, assertErrorName,
- loopAName, choiceAName, appAName, arrAName, composeAName, firstAName,
- negateName, thenMName, bindMName, failMName, groupWithName )
+import PrelNames
import Name
import NameSet
import RdrName
import LoadIface ( loadInterfaceForName )
import UniqSet
-import List ( nub )
-import Util ( isSingleton )
+import Data.List
+import Util ( isSingleton, snocView )
import ListSetOps ( removeDups )
-import Maybes ( expectJust )
import Outputable
import SrcLoc
import FastString
-
-import List ( unzip4 )
import Control.Monad
\end{code}
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}
%************************************************************************
rnExprs :: [LHsExpr RdrName] -> RnM ([LHsExpr Name], FreeVars)
rnExprs ls = rnExprs' ls emptyUniqSet
where
- rnExprs' [] acc = returnM ([], acc)
+ rnExprs' [] acc = return ([], acc)
rnExprs' (expr:exprs) acc
= rnLExpr expr `thenM` \ (expr', fvExpr) ->
acc' = acc `plusFV` fvExpr
in
acc' `seq` rnExprs' exprs acc' `thenM` \ (exprs', fvExprs) ->
- returnM (expr':exprs', fvExprs)
+ return (expr':exprs', fvExprs)
\end{code}
Variables. We look up the variable and return the resulting name.
rnExpr (HsIPVar v)
= newIPNameRn v `thenM` \ name ->
- returnM (HsIPVar name, emptyFVs)
+ return (HsIPVar name, emptyFVs)
rnExpr (HsLit lit@(HsString s))
= do {
- opt_OverloadedStrings <- doptM Opt_OverloadedStrings
+ opt_OverloadedStrings <- xoptM Opt_OverloadedStrings
; if opt_OverloadedStrings then
rnExpr (HsOverLit (mkHsIsString s placeHolderType))
else -- Same as below
rnLit lit `thenM_`
- returnM (HsLit lit, emptyFVs)
+ return (HsLit lit, emptyFVs)
}
rnExpr (HsLit lit)
= rnLit lit `thenM_`
- returnM (HsLit lit, emptyFVs)
+ return (HsLit lit, emptyFVs)
rnExpr (HsOverLit lit)
= rnOverLit lit `thenM` \ (lit', fvs) ->
- returnM (HsOverLit lit', fvs)
+ return (HsOverLit lit', fvs)
rnExpr (HsApp fun arg)
= rnLExpr fun `thenM` \ (fun',fvFun) ->
rnLExpr arg `thenM` \ (arg',fvArg) ->
- returnM (HsApp fun' arg', fvFun `plusFV` fvArg)
+ return (HsApp fun' arg', fvFun `plusFV` fvArg)
-rnExpr (OpApp e1 (L op_loc (HsVar op_rdr)) _ e2)
- = do { (e1', fv_e1) <- rnLExpr e1
+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
; 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 (OpApp _ other_op _ _)
+ = failWith (vcat [ hang (ptext (sLit "Operator application with a non-variable operator:"))
+ 2 (ppr other_op)
+ , ptext (sLit "(Probably resulting from a Template Haskell splice)") ])
rnExpr (NegApp e _)
= rnLExpr e `thenM` \ (e', fv_e) ->
lookupSyntaxName negateName `thenM` \ (neg_name, fv_neg) ->
mkNegAppRn e' neg_name `thenM` \ final_e ->
- returnM (final_e, fv_e `plusFV` fv_neg)
+ return (final_e, fv_e `plusFV` fv_neg)
------------------------------------------
-- Template Haskell extensions
rnExpr e@(HsBracket br_body)
= checkTH e "bracket" `thenM_`
rnBracket br_body `thenM` \ (body', fvs_e) ->
- returnM (HsBracket body', fvs_e)
+ return (HsBracket body', fvs_e)
rnExpr (HsSpliceE splice)
= rnSplice splice `thenM` \ (splice', fvs) ->
- returnM (HsSpliceE splice', fvs)
+ return (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)
+ = runQuasiQuoteExpr qq `thenM` \ (L _ expr') ->
+ rnExpr expr'
#endif /* GHCI */
---------------------------------------------
---------------------------------------------
rnExpr (HsCoreAnn ann expr)
= rnLExpr expr `thenM` \ (expr', fvs_expr) ->
- returnM (HsCoreAnn ann expr', fvs_expr)
+ return (HsCoreAnn ann expr', fvs_expr)
rnExpr (HsSCC lbl expr)
= rnLExpr expr `thenM` \ (expr', fvs_expr) ->
- returnM (HsSCC lbl expr', fvs_expr)
+ return (HsSCC lbl expr', fvs_expr)
rnExpr (HsTickPragma info expr)
= rnLExpr expr `thenM` \ (expr', fvs_expr) ->
- returnM (HsTickPragma info expr', fvs_expr)
+ return (HsTickPragma info expr', fvs_expr)
rnExpr (HsLam matches)
= rnMatchGroup LambdaExpr matches `thenM` \ (matches', fvMatch) ->
- returnM (HsLam matches', fvMatch)
+ return (HsLam matches', fvMatch)
rnExpr (HsCase expr matches)
= rnLExpr expr `thenM` \ (new_expr, e_fvs) ->
rnMatchGroup CaseAlt matches `thenM` \ (new_matches, ms_fvs) ->
- returnM (HsCase new_expr new_matches, e_fvs `plusFV` ms_fvs)
+ return (HsCase new_expr new_matches, e_fvs `plusFV` ms_fvs)
rnExpr (HsLet binds expr)
= rnLocalBindsAndThen binds $ \ binds' ->
rnLExpr expr `thenM` \ (expr',fvExpr) ->
- returnM (HsLet binds' expr', fvExpr)
+ return (HsLet binds' expr', fvExpr)
-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 (HsDo do_or_lc stmts _)
+ = do { ((stmts', _), fvs) <- rnStmts do_or_lc stmts (\ _ -> return ((), emptyFVs))
+ ; return ( HsDo do_or_lc stmts' placeHolderType, fvs ) }
rnExpr (ExplicitList _ exps)
= rnExprs exps `thenM` \ (exps', fvs) ->
- returnM (ExplicitList placeHolderType exps', fvs)
+ return (ExplicitList placeHolderType exps', fvs)
rnExpr (ExplicitPArr _ exps)
= rnExprs exps `thenM` \ (exps', fvs) ->
- returnM (ExplicitPArr placeHolderType exps', fvs)
+ return (ExplicitPArr placeHolderType exps', fvs)
-rnExpr (ExplicitTuple exps boxity)
- = checkTupSize (length exps) `thenM_`
- rnExprs exps `thenM` \ (exps', fvs) ->
- returnM (ExplicitTuple exps' boxity, fvs)
+rnExpr (ExplicitTuple tup_args boxity)
+ = do { checkTupleSection tup_args
+ ; checkTupSize (length tup_args)
+ ; (tup_args', fvs) <- mapAndUnzipM rnTupArg tup_args
+ ; return (ExplicitTuple tup_args' boxity, plusFVs fvs) }
+ where
+ rnTupArg (Present e) = do { (e',fvs) <- rnLExpr e; return (Present e', fvs) }
+ rnTupArg (Missing _) = return (Missing placeHolderType, emptyFVs)
rnExpr (RecordCon con_id _ rbinds)
= do { conname <- lookupLocatedOccRn con_id
- ; (rbinds', fvRbinds) <- rnHsRecFields_Con conname rnLExpr rbinds
+ ; (rbinds', fvRbinds) <- rnHsRecBinds (HsRecFieldCon (unLoc conname)) rbinds
; return (RecordCon conname noPostTcExpr rbinds',
fvRbinds `addOneFV` unLoc conname) }
rnExpr (RecordUpd expr rbinds _ _ _)
= do { (expr', fvExpr) <- rnLExpr expr
- ; (rbinds', fvRbinds) <- rnHsRecFields_Update rnLExpr rbinds
+ ; (rbinds', fvRbinds) <- rnHsRecBinds HsRecFieldUpd rbinds
; return (RecordUpd expr' rbinds' [] [] [],
fvExpr `plusFV` fvRbinds) }
where
doc = text "In an expression type signature"
-rnExpr (HsIf p b1 b2)
- = rnLExpr p `thenM` \ (p', fvP) ->
- rnLExpr b1 `thenM` \ (b1', fvB1) ->
- rnLExpr b2 `thenM` \ (b2', fvB2) ->
- returnM (HsIf p' b1' b2', plusFVs [fvP, fvB1, fvB2])
+rnExpr (HsIf _ p b1 b2)
+ = do { (p', fvP) <- rnLExpr p
+ ; (b1', fvB1) <- rnLExpr b1
+ ; (b2', fvB2) <- rnLExpr b2
+ ; (mb_ite, fvITE) <- lookupIfThenElse
+ ; return (HsIf mb_ite p' b1' b2', plusFVs [fvITE, fvP, fvB1, fvB2]) }
rnExpr (HsType a)
= rnHsTypeFVs doc a `thenM` \ (t, fvT) ->
- returnM (HsType t, fvT)
+ return (HsType t, fvT)
where
doc = text "In a type argument"
rnExpr (ArithSeq _ seq)
= rnArithSeq seq `thenM` \ (new_seq, fvs) ->
- returnM (ArithSeq noPostTcExpr new_seq, fvs)
+ return (ArithSeq noPostTcExpr new_seq, fvs)
rnExpr (PArrSeq _ seq)
= rnArithSeq seq `thenM` \ (new_seq, fvs) ->
- returnM (PArrSeq noPostTcExpr new_seq, fvs)
+ return (PArrSeq noPostTcExpr new_seq, fvs)
\end{code}
These three are pattern syntax appearing in expressions.
\begin{code}
rnExpr (HsProc pat body)
= newArrowScope $
- rnPatsAndThen_LocalRightwards ProcExpr [pat] $ \ [pat'] ->
+ rnPat ProcExpr pat $ \ pat' ->
rnCmdTop body `thenM` \ (body',fvBody) ->
- returnM (HsProc pat' body', fvBody)
+ return (HsProc pat' body', fvBody)
rnExpr (HsArrApp arrow arg _ ho rtl)
= select_arrow_scope (rnLExpr arrow) `thenM` \ (arrow',fvArrow) ->
rnLExpr arg `thenM` \ (arg',fvArg) ->
- returnM (HsArrApp arrow' arg' placeHolderType ho rtl,
+ return (HsArrApp arrow' arg' placeHolderType ho rtl,
fvArrow `plusFV` fvArg)
where
select_arrow_scope tc = case ho of
-- infix form
rnExpr (HsArrForm op (Just _) [arg1, arg2])
= escapeArrowScope (rnLExpr op)
- `thenM` \ (op'@(L _ (HsVar op_name)),fv_op) ->
+ `thenM` \ (op',fv_op) ->
+ let L _ (HsVar op_name) = op' in
rnCmdTop arg1 `thenM` \ (arg1',fv_arg1) ->
rnCmdTop arg2 `thenM` \ (arg2',fv_arg2) ->
lookupFixityRn op_name `thenM` \ fixity ->
mkOpFormRn arg1' op' fixity arg2' `thenM` \ final_e ->
- returnM (final_e,
+ return (final_e,
fv_arg1 `plusFV` fv_op `plusFV` fv_arg2)
rnExpr (HsArrForm op fixity cmds)
= escapeArrowScope (rnLExpr op) `thenM` \ (op',fvOp) ->
rnCmdArgs cmds `thenM` \ (cmds',fvCmds) ->
- returnM (HsArrForm op' fixity cmds', fvOp `plusFV` fvCmds)
+ return (HsArrForm op' fixity cmds', fvOp `plusFV` fvCmds)
rnExpr other = pprPanic "rnExpr: unexpected expression" (ppr other)
-- HsWrap
%************************************************************************
%* *
+ Records
+%* *
+%************************************************************************
+
+\begin{code}
+rnHsRecBinds :: HsRecFieldContext -> HsRecordBinds RdrName
+ -> RnM (HsRecordBinds Name, FreeVars)
+rnHsRecBinds ctxt rec_binds@(HsRecFields { rec_dotdot = dd })
+ = do { (flds, fvs) <- rnHsRecFields1 ctxt HsVar rec_binds
+ ; (flds', fvss) <- mapAndUnzipM rn_field flds
+ ; return (HsRecFields { rec_flds = flds', rec_dotdot = dd },
+ fvs `plusFV` plusFVs fvss) }
+ where
+ rn_field fld = do { (arg', fvs) <- rnLExpr (hsRecFieldArg fld)
+ ; return (fld { hsRecFieldArg = arg' }, fvs) }
+\end{code}
+
+
+%************************************************************************
+%* *
Arrow commands
%* *
%************************************************************************
\begin{code}
rnCmdArgs :: [LHsCmdTop RdrName] -> RnM ([LHsCmdTop Name], FreeVars)
-rnCmdArgs [] = returnM ([], emptyFVs)
+rnCmdArgs [] = return ([], emptyFVs)
rnCmdArgs (arg:args)
= rnCmdTop arg `thenM` \ (arg',fvArg) ->
rnCmdArgs args `thenM` \ (args',fvArgs) ->
- returnM (arg':args', fvArg `plusFV` fvArgs)
+ return (arg':args', fvArg `plusFV` fvArgs)
rnCmdTop :: LHsCmdTop RdrName -> RnM (LHsCmdTop Name, FreeVars)
rnCmdTop = wrapLocFstM rnCmdTop'
-- Generate the rebindable syntax for the monad
lookupSyntaxTable cmd_names `thenM` \ (cmd_names', cmd_fvs) ->
- returnM (HsCmdTop cmd' [] placeHolderType cmd_names',
+ return (HsCmdTop cmd' [] placeHolderType cmd_names',
fvCmd `plusFV` cmd_fvs)
---------------------------------------------------
convertOpFormsCmd (HsCase exp matches)
= HsCase exp (convertOpFormsMatch matches)
-convertOpFormsCmd (HsIf exp c1 c2)
- = HsIf exp (convertOpFormsLCmd c1) (convertOpFormsLCmd c2)
+convertOpFormsCmd (HsIf f exp c1 c2)
+ = HsIf f exp (convertOpFormsLCmd c1) (convertOpFormsLCmd c2)
convertOpFormsCmd (HsLet binds cmd)
= HsLet binds (convertOpFormsLCmd cmd)
-convertOpFormsCmd (HsDo ctxt stmts body ty)
- = HsDo ctxt (map (fmap convertOpFormsStmt) stmts)
- (convertOpFormsLCmd body) ty
+convertOpFormsCmd (HsDo ctxt stmts ty)
+ = HsDo ctxt (map (fmap convertOpFormsStmt) stmts) ty
-- Anything else is unchanged. This includes HsArrForm (already done),
-- things with no sub-commands, and illegal commands (which will be
convertOpFormsStmt :: StmtLR id id -> StmtLR id id
convertOpFormsStmt (BindStmt pat cmd _ _)
= BindStmt pat (convertOpFormsLCmd cmd) noSyntaxExpr noSyntaxExpr
-convertOpFormsStmt (ExprStmt cmd _ _)
- = ExprStmt (convertOpFormsLCmd cmd) noSyntaxExpr placeHolderType
-convertOpFormsStmt (RecStmt stmts lvs rvs es binds)
- = RecStmt (map (fmap convertOpFormsStmt) stmts) lvs rvs es binds
+convertOpFormsStmt (ExprStmt cmd _ _ _)
+ = ExprStmt (convertOpFormsLCmd cmd) noSyntaxExpr noSyntaxExpr placeHolderType
+convertOpFormsStmt stmt@(RecStmt { recS_stmts = stmts })
+ = stmt { recS_stmts = map (fmap convertOpFormsStmt) stmts }
convertOpFormsStmt stmt = stmt
convertOpFormsMatch :: MatchGroup id -> MatchGroup id
methodNamesCmd (HsPar c) = methodNamesLCmd c
-methodNamesCmd (HsIf _ c1 c2)
+methodNamesCmd (HsIf _ _ c1 c2)
= methodNamesLCmd c1 `plusFV` methodNamesLCmd c2 `addOneFV` choiceAName
-methodNamesCmd (HsLet _ c) = methodNamesLCmd c
-
-methodNamesCmd (HsDo _ stmts body _)
- = methodNamesStmts stmts `plusFV` methodNamesLCmd body
-
-methodNamesCmd (HsApp c _) = methodNamesLCmd c
-
-methodNamesCmd (HsLam match) = methodNamesMatch match
+methodNamesCmd (HsLet _ c) = methodNamesLCmd c
+methodNamesCmd (HsDo _ stmts _) = methodNamesStmts stmts
+methodNamesCmd (HsApp c _) = methodNamesLCmd c
+methodNamesCmd (HsLam match) = methodNamesMatch match
methodNamesCmd (HsCase _ matches)
= methodNamesMatch matches `addOneFV` choiceAName
methodNamesLStmt = methodNamesStmt . unLoc
methodNamesStmt :: StmtLR Name Name -> FreeVars
-methodNamesStmt (ExprStmt cmd _ _) = methodNamesLCmd cmd
-methodNamesStmt (BindStmt _ cmd _ _) = methodNamesLCmd cmd
-methodNamesStmt (RecStmt stmts _ _ _ _)
- = methodNamesStmts stmts `addOneFV` loopAName
-methodNamesStmt (LetStmt _) = emptyFVs
-methodNamesStmt (ParStmt _) = emptyFVs
-methodNamesStmt (TransformStmt _ _ _) = emptyFVs
-methodNamesStmt (GroupStmt _ _) = emptyFVs
+methodNamesStmt (LastStmt cmd _) = methodNamesLCmd cmd
+methodNamesStmt (ExprStmt cmd _ _ _) = methodNamesLCmd cmd
+methodNamesStmt (BindStmt _ cmd _ _) = methodNamesLCmd cmd
+methodNamesStmt (RecStmt { recS_stmts = stmts }) = methodNamesStmts stmts `addOneFV` loopAName
+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}
rnArithSeq :: ArithSeqInfo RdrName -> RnM (ArithSeqInfo Name, FreeVars)
rnArithSeq (From expr)
= rnLExpr expr `thenM` \ (expr', fvExpr) ->
- returnM (From expr', fvExpr)
+ return (From expr', fvExpr)
rnArithSeq (FromThen expr1 expr2)
= rnLExpr expr1 `thenM` \ (expr1', fvExpr1) ->
rnLExpr expr2 `thenM` \ (expr2', fvExpr2) ->
- returnM (FromThen expr1' expr2', fvExpr1 `plusFV` fvExpr2)
+ return (FromThen expr1' expr2', fvExpr1 `plusFV` fvExpr2)
rnArithSeq (FromTo expr1 expr2)
= rnLExpr expr1 `thenM` \ (expr1', fvExpr1) ->
rnLExpr expr2 `thenM` \ (expr2', fvExpr2) ->
- returnM (FromTo expr1' expr2', fvExpr1 `plusFV` fvExpr2)
+ return (FromTo expr1' expr2', fvExpr1 `plusFV` fvExpr2)
rnArithSeq (FromThenTo expr1 expr2 expr3)
= rnLExpr expr1 `thenM` \ (expr1', fvExpr1) ->
rnLExpr expr2 `thenM` \ (expr2', fvExpr2) ->
rnLExpr expr3 `thenM` \ (expr3', fvExpr3) ->
- returnM (FromThenTo expr1' expr2' expr3',
+ return (FromThenTo expr1' expr2' expr3',
plusFVs [fvExpr1, fvExpr2, fvExpr3])
\end{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
- do { loadInterfaceForName msg name -- home interface is loaded, and this is the
+ ; unless (nameIsLocalOrFrom this_mod name) $ -- Reason: deprecation checking asumes the
+ do { _ <- loadInterfaceForName msg name -- home interface is loaded, and this is the
; return () } -- only way that is going to happen
- ; returnM (VarBr name, unitFV name) }
+ ; return (VarBr name, unitFV name) }
where
msg = ptext (sLit "Need interface for Template Haskell quoted Name")
rnBracket (ExpBr e) = do { (e', fvs) <- rnLExpr e
; return (ExpBr e', fvs) }
-rnBracket (PatBr _) = failWith (ptext (sLit "Tempate Haskell pattern brackets are not supported yet"))
+rnBracket (PatBr p) = rnPat ThPatQuote p $ \ p' -> return (PatBr p', emptyFVs)
+
rnBracket (TypBr t) = do { (t', fvs) <- rnHsTypeFVs doc t
; return (TypBr t', fvs) }
where
doc = ptext (sLit "In a Template-Haskell quoted type")
-rnBracket (DecBr group)
- = do { gbl_env <- getGblEnv
- ; let new_gbl_env = gbl_env { tcg_dus = emptyDUs }
+rnBracket (DecBrL decls)
+ = do { (group, mb_splice) <- findSplice decls
+ ; case mb_splice of
+ Nothing -> return ()
+ Just (SpliceDecl (L loc _) _, _)
+ -> setSrcSpan loc $
+ addErr (ptext (sLit "Declaration splices are not permitted inside declaration brackets"))
+ -- Why not? See Section 7.3 of the TH paper.
+
+ ; gbl_env <- getGblEnv
+ ; 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)) }
+ -- Discard the tcg_env; it contains only extra info about fixity
+ ; traceRn (text "rnBracket dec" <+> (ppr (tcg_dus tcg_env) $$ ppr (duUses (tcg_dus tcg_env))))
+ ; return (DecBrG group', duUses (tcg_dus tcg_env)) }
+
+rnBracket (DecBrG _) = panic "rnBracket: unexpected DecBrG"
\end{code}
%************************************************************************
%************************************************************************
\begin{code}
-rnStmts :: HsStmtContext Name -> [LStmt RdrName]
- -> RnM (thing, FreeVars)
- -> RnM (([LStmt Name], thing), FreeVars)
-
-rnStmts (MDoExpr _) = rnMDoStmts
-rnStmts ctxt = rnNormalStmts ctxt
-
-rnNormalStmts :: HsStmtContext Name -> [LStmt RdrName]
- -> RnM (thing, FreeVars)
- -> RnM (([LStmt Name], thing), FreeVars)
--- Used for cases *other* than recursive mdo
--- Implements nested scopes
-
-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
- ; return (((L loc stmt' : stmts'), thing), fvs) }
-
+rnStmts :: HsStmtContext Name -> [LStmt RdrName]
+ -> ([Name] -> RnM (thing, FreeVars))
+ -> RnM (([LStmt Name], thing), FreeVars)
+-- Variables bound by the Stmts, and mentioned in thing_inside,
+-- do not appear in the result FreeVars
+
+rnStmts ctxt [] thing_inside
+ = do { checkEmptyStmts ctxt
+ ; (thing, fvs) <- thing_inside []
+ ; return (([], thing), fvs) }
+
+rnStmts MDoExpr stmts thing_inside -- Deal with mdo
+ = -- Behave like do { rec { ...all but last... }; last }
+ do { ((stmts1, (stmts2, thing)), fvs)
+ <- rnStmt MDoExpr (noLoc $ mkRecStmt all_but_last) $ \ _ ->
+ do { checkStmt MDoExpr True last_stmt
+ ; rnStmt MDoExpr last_stmt thing_inside }
+ ; return (((stmts1 ++ stmts2), thing), fvs) }
+ where
+ Just (all_but_last, last_stmt) = snocView stmts
+
+rnStmts ctxt (lstmt@(L loc stmt) : lstmts) thing_inside
+ | null lstmts
+ = setSrcSpan loc $
+ do { -- Turn a final ExprStmt into a LastStmt
+ -- This is the first place it's convenient to do this
+ -- (In principle the parser could do it, but it's
+ -- just not very convenient to do so.)
+ let stmt' | okEmpty ctxt
+ = lstmt
+ | otherwise
+ = case stmt of
+ ExprStmt e _ _ _ -> L loc (mkLastStmt e)
+ _ -> lstmt
+ ; checkStmt ctxt True {- last stmt -} stmt'
+ ; rnStmt ctxt stmt' thing_inside }
+
+ | otherwise
+ = do { ((stmts1, (stmts2, thing)), fvs)
+ <- setSrcSpan loc $
+ do { checkStmt ctxt False {- Not last -} lstmt
+ ; rnStmt ctxt lstmt $ \ bndrs1 ->
+ rnStmts ctxt lstmts $ \ bndrs2 ->
+ thing_inside (bndrs1 ++ bndrs2) }
+ ; return (((stmts1 ++ stmts2), thing), fvs) }
-rnStmt :: HsStmtContext Name -> Stmt RdrName
- -> RnM (thing, FreeVars)
- -> RnM ((Stmt Name, thing), FreeVars)
+----------------------
+rnStmt :: HsStmtContext Name
+ -> LStmt RdrName
+ -> ([Name] -> RnM (thing, FreeVars))
+ -> RnM (([LStmt Name], thing), FreeVars)
+-- Variables bound by the Stmt, and mentioned in thing_inside,
+-- do not appear in the result FreeVars
+
+rnStmt _ (L loc (LastStmt expr _)) thing_inside
+ = do { (expr', fv_expr) <- rnLExpr expr
+ ; (ret_op, fvs1) <- lookupSyntaxName returnMName
+ ; (thing, fvs3) <- thing_inside []
+ ; return (([L loc (LastStmt expr' ret_op)], thing),
+ fv_expr `plusFV` fvs1 `plusFV` fvs3) }
-rnStmt _ (ExprStmt expr _ _) thing_inside
+rnStmt ctxt (L loc (ExprStmt expr _ _ _)) thing_inside
= do { (expr', fv_expr) <- rnLExpr expr
; (then_op, fvs1) <- lookupSyntaxName thenMName
- ; (thing, fvs2) <- thing_inside
- ; return ((ExprStmt expr' then_op placeHolderType, thing),
- fv_expr `plusFV` fvs1 `plusFV` fvs2) }
-
-rnStmt ctxt (BindStmt pat expr _ _) thing_inside
+ ; (guard_op, fvs2) <- if isMonadCompExpr ctxt
+ then lookupSyntaxName guardMName
+ else return (noSyntaxExpr, emptyFVs)
+ ; (thing, fvs3) <- thing_inside []
+ ; return (([L loc (ExprStmt expr' then_op guard_op placeHolderType)], thing),
+ fv_expr `plusFV` fvs1 `plusFV` fvs2 `plusFV` fvs3) }
+
+rnStmt ctxt (L loc (BindStmt pat expr _ _)) thing_inside
= do { (expr', fv_expr) <- rnLExpr expr
-- 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
- { (thing, fvs3) <- thing_inside
- ; return ((BindStmt pat' expr' bind_op fail_op, thing),
+ ; rnPat (StmtCtxt ctxt) pat $ \ pat' -> do
+ { (thing, fvs3) <- thing_inside (collectPatBinders pat')
+ ; return (([L loc (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 { checkLetStmt ctxt binds
- ; rnLocalBindsAndThen binds $ \binds' -> do
- { (thing, fvs) <- thing_inside
- ; return ((LetStmt binds', thing), fvs) } }
+rnStmt _ (L loc (LetStmt binds)) thing_inside
+ = do { rnLocalBindsAndThen binds $ \binds' -> do
+ { (thing, fvs) <- thing_inside (collectLocalBinders binds')
+ ; return (([L loc (LetStmt binds')], thing), fvs) } }
-rnStmt ctxt (RecStmt rec_stmts _ _ _ _) thing_inside
- = do { checkRecStmt ctxt
- ; rn_rec_stmts_and_then rec_stmts $ \ segs -> do
- { (thing, fvs) <- thing_inside
+rnStmt _ (L _ (RecStmt { recS_stmts = rec_stmts })) thing_inside
+ = do {
+ -- 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.)
+ ; rnRecStmtsAndThen rec_stmts $ \ segs -> do
+
+ { let bndrs = nameSetToList $ foldr (unionNameSets . (\(ds,_,_,_) -> ds))
+ emptyNameSet segs
+ ; (thing, fvs_later) <- thing_inside bndrs
+ ; (return_op, fvs1) <- lookupSyntaxName returnMName
+ ; (mfix_op, fvs2) <- lookupSyntaxName mfixName
+ ; (bind_op, fvs3) <- lookupSyntaxName bindMName
; let
+ -- 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
- (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 { 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
- rnMaybeLExpr Nothing = return (Nothing, emptyFVs)
- rnMaybeLExpr (Just expr) = do
- (expr', fv_expr) <- rnLExpr expr
- return (Just expr', fv_expr)
+
+ -- 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 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
+ -- used 'after' the RecStmt
+ empty_rec_stmt = emptyRecStmt { recS_ret_fn = return_op
+ , recS_mfix_fn = mfix_op
+ , recS_bind_fn = bind_op }
+ (rec_stmts', fvs) = segsToStmts empty_rec_stmt grouped_segs fvs_later
+
+ ; return ((rec_stmts', thing), fvs `plusFV` fvs1 `plusFV` fvs2 `plusFV` fvs3) } }
+
+rnStmt ctxt (L loc (ParStmt segs _ _ _)) thing_inside
+ = do { ((mzip_op, fvs1), (bind_op, fvs2), (return_op, fvs3)) <- if isMonadCompExpr ctxt
+ then (,,) <$> lookupSyntaxName mzipName
+ <*> lookupSyntaxName bindMName
+ <*> lookupSyntaxName returnMName
+ else return ( (noSyntaxExpr, emptyFVs)
+ , (noSyntaxExpr, emptyFVs)
+ , (noSyntaxExpr, emptyFVs) )
+ ; ((segs', thing), fvs4) <- rnParallelStmts (ParStmtCtxt ctxt) segs thing_inside
+ ; return ( ([L loc (ParStmt segs' mzip_op bind_op return_op)], thing)
+ , fvs1 `plusFV` fvs2 `plusFV` fvs3 `plusFV` fvs4) }
+
+rnStmt ctxt (L loc (TransformStmt stmts _ using by _ _)) thing_inside
+ = do { (using', fvs1) <- rnLExpr using
+
+ ; ((stmts', (by', used_bndrs, thing)), fvs2)
+ <- rnStmts (TransformStmtCtxt ctxt) stmts $ \ bndrs ->
+ do { (by', fvs_by) <- case by of
+ Nothing -> return (Nothing, emptyFVs)
+ Just e -> do { (e', fvs) <- rnLExpr e; return (Just e', fvs) }
+ ; (thing, fvs_thing) <- thing_inside bndrs
+ ; let fvs = fvs_by `plusFV` fvs_thing
+ used_bndrs = filter (`elemNameSet` fvs) bndrs
+ -- The paper (Fig 5) has a bug here; we must treat any free varaible of
+ -- the "thing inside", **or of the by-expression**, as used
+ ; return ((by', used_bndrs, thing), fvs) }
+
+ -- Lookup `(>>=)` and `fail` for monad comprehensions
+ ; ((return_op, fvs3), (bind_op, fvs4)) <-
+ if isMonadCompExpr ctxt
+ then (,) <$> lookupSyntaxName returnMName
+ <*> lookupSyntaxName bindMName
+ else return ( (noSyntaxExpr, emptyFVs)
+ , (noSyntaxExpr, emptyFVs) )
+
+ ; return (([L loc (TransformStmt stmts' used_bndrs using' by' return_op bind_op)], thing),
+ fvs1 `plusFV` fvs2 `plusFV` fvs3 `plusFV` fvs4) }
-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:")
+rnStmt ctxt (L loc (GroupStmt { grpS_stmts = stmts, grpS_by = by, grpS_explicit = explicit
+ , grpS_using = using })) thing_inside
+ = do { -- Rename the 'using' expression in the context before the transform is begun
+ let implicit_name | isMonadCompExpr ctxt = groupMName
+ | otherwise = groupWithName
+ ; (using', fvs1) <- if explicit
+ then rnLExpr using
+ else do { (e,fvs) <- lookupSyntaxName implicit_name
+ ; return (noLoc e, fvs) }
+
+ -- Rename the stmts and the 'by' expression
+ -- Keep track of the variables mentioned in the 'by' expression
+ ; ((stmts', (by', used_bndrs, thing)), fvs2)
+ <- rnStmts (TransformStmtCtxt ctxt) stmts $ \ bndrs ->
+ do { (by', fvs_by) <- mapMaybeFvRn rnLExpr by
+ ; (thing, fvs_thing) <- thing_inside bndrs
+ ; let fvs = fvs_by `plusFV` fvs_thing
+ used_bndrs = filter (`elemNameSet` fvs) bndrs
+ ; return ((by', used_bndrs, thing), fvs) }
+
+ -- Lookup `return`, `(>>=)` and `liftM` for monad comprehensions
+ ; ((return_op, fvs3), (bind_op, fvs4), (fmap_op, fvs5)) <-
+ if isMonadCompExpr ctxt
+ then (,,) <$> lookupSyntaxName returnMName
+ <*> lookupSyntaxName bindMName
+ <*> lookupSyntaxName fmapName
+ else return ( (noSyntaxExpr, emptyFVs)
+ , (noSyntaxExpr, emptyFVs)
+ , (noSyntaxExpr, emptyFVs) )
+
+ ; let all_fvs = fvs1 `plusFV` fvs2 `plusFV` fvs3 `plusFV` fvs4
+ `plusFV` fvs5
+ bndr_map = used_bndrs `zip` used_bndrs
+ -- See Note [GroupStmt binder map] in HsExpr
+
+ ; traceRn (text "rnStmt: implicitly rebound these used binders:" <+> ppr bndr_map)
+ ; return (([L loc (GroupStmt { grpS_stmts = stmts', grpS_bndrs = bndr_map
+ , grpS_by = by', grpS_using = using', grpS_explicit = explicit
+ , grpS_ret = return_op, grpS_bind = bind_op
+ , grpS_fmap = fmap_op })], thing), all_fvs) }
+
+type ParSeg id = ([LStmt id], [id]) -- The Names are bound by the Stmts
+
+rnParallelStmts :: forall thing. HsStmtContext Name
+ -> [ParSeg RdrName]
+ -> ([Name] -> RnM (thing, FreeVars))
+ -> RnM (([ParSeg Name], thing), FreeVars)
+-- Note [Renaming parallel Stmts]
+rnParallelStmts ctxt segs thing_inside
+ = do { orig_lcl_env <- getLocalRdrEnv
+ ; rn_segs orig_lcl_env [] segs }
+ where
+ rn_segs :: LocalRdrEnv
+ -> [Name] -> [ParSeg RdrName]
+ -> RnM (([ParSeg Name], thing), FreeVars)
+ rn_segs _ bndrs_so_far []
+ = do { let (bndrs', dups) = removeDups cmpByOcc bndrs_so_far
+ ; mapM_ dupErr dups
+ ; (thing, fvs) <- bindLocalNames bndrs' (thing_inside bndrs')
+ ; return (([], thing), fvs) }
+
+ rn_segs env bndrs_so_far ((stmts,_) : segs)
+ = do { ((stmts', (used_bndrs, segs', thing)), fvs)
+ <- rnStmts ctxt stmts $ \ bndrs ->
+ setLocalRdrEnv env $ do
+ { ((segs', thing), fvs) <- rn_segs env (bndrs ++ bndrs_so_far) segs
+ ; let used_bndrs = filter (`elemNameSet` fvs) bndrs
+ ; return ((used_bndrs, segs', thing), fvs) }
+
+ ; let seg' = (stmts', used_bndrs)
+ ; return ((seg':segs', thing), fvs) }
+
+ 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}
+Note [Renaming parallel Stmts]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Renaming parallel statements is painful. Given, say
+ [ a+c | a <- as, bs <- bss
+ | c <- bs, a <- ds ]
+Note that
+ (a) In order to report "Defined by not used" about 'bs', we must rename
+ each group of Stmts with a thing_inside whose FreeVars include at least {a,c}
+
+ (b) We want to report that 'a' is illegally bound in both branches
+
+ (c) The 'bs' in the second group must obviously not be captured by
+ the binding in the first group
+
+To satisfy (a) we nest the segements.
+To satisfy (b) we check for duplicates just before thing_inside.
+To satisfy (c) we reset the LocalRdrEnv each time.
%************************************************************************
%* *
stmts) -- Either Stmt or [Stmt]
-----------------------------------------------------
-
-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.)
- -- 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 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 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 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
- -- used 'after' the RecStmt
- (stmts', fvs) = segsToStmts grouped_segs fvs_later
-
- ; return ((stmts', thing), fvs) }
-
----------------------------------------------
-
-- wrapper that does both the left- and right-hand sides
-rn_rec_stmts_and_then :: [LStmt RdrName]
+rnRecStmtsAndThen :: [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
+rnRecStmtsAndThen s cont
= do { -- (A) Make the mini fixity env for all of the stmts
fix_env <- makeMiniFixityEnv (collectRecStmtsFixities s)
; 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
+ ; let bound_names = collectLStmtsBinders (map fst new_lhs_and_fv)
+ -- Fake uses of variables introduced implicitly (warning suppression, see #4404)
+ implicit_uses = lStmtsImplicits (map fst new_lhs_and_fv)
+ ; bindLocalNamesFV bound_names $
+ addLocalFixities fix_env bound_names $ 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
+ ; warnUnusedLocalBinds bound_names (fvs `unionNameSets` implicit_uses)
; return (res, fvs) }}
-- get all the fixity decls in any Let stmt
-- 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 _ (L loc (ExprStmt expr a b c))
+ = return [(L loc (ExprStmt expr a b c), emptyFVs)]
+
+rn_rec_stmt_lhs _ (L loc (LastStmt expr a))
+ = return [(L loc (LastStmt expr a), emptyFVs)]
rn_rec_stmt_lhs fix_env (L loc (BindStmt pat expr a b))
= do
= 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
+ = do (_bound_names, binds') <- rnLocalValBindsLHS 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
+-- XXX Do we need to do something with the return and mfix names?
+rn_rec_stmt_lhs fix_env (L _ (RecStmt { recS_stmts = stmts })) -- Flatten Rec inside Rec
= rn_rec_stmts_lhs fix_env stmts
-rn_rec_stmt_lhs _ stmt@(L _ (ParStmt _)) -- Syntactically illegal in mdo
+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
+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
+rn_rec_stmt_lhs _ stmt@(L _ (GroupStmt {})) -- Syntactically illegal in mdo
= pprPanic "rn_rec_stmt" (ppr stmt)
rn_rec_stmt_lhs _ (L _ (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)
+rn_rec_stmts_lhs fix_env stmts
+ = do { ls <- concatMapM (rn_rec_stmt_lhs fix_env) stmts
+ ; let boundNames = collectLStmtsBinders (map fst ls)
+ -- 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 boundNames
+ ; return ls }
-- right-hand-sides
-- 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 _ (L loc (ExprStmt expr _ _)) _
+rn_rec_stmt _ (L loc (LastStmt expr _)) _
+ = do { (expr', fv_expr) <- rnLExpr expr
+ ; (ret_op, fvs1) <- lookupSyntaxName returnMName
+ ; return [(emptyNameSet, fv_expr `plusFV` fvs1, emptyNameSet,
+ L loc (LastStmt expr' ret_op))] }
+
+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))]
+ return [(emptyNameSet, fvs `plusFV` fvs1, emptyNameSet,
+ L loc (ExprStmt expr' then_op noSyntaxExpr placeHolderType))]
rn_rec_stmt _ (L loc (BindStmt pat' expr _ _)) fv_pat
= rnLExpr expr `thenM` \ (expr', fv_expr) ->
bndrs = mkNameSet (collectPatBinders pat')
fvs = fv_expr `plusFV` fv_pat `plusFV` fvs1 `plusFV` fvs2
in
- returnM [(bndrs, fvs, bndrs `intersectNameSet` fvs,
+ return [(bndrs, fvs, bndrs `intersectNameSet` fvs,
L loc (BindStmt pat' expr' bind_op fail_op))]
rn_rec_stmt _ (L _ (LetStmt binds@(HsIPBinds _))) _
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 (mkNameSet all_bndrs) binds'
- returnM [(duDefs du_binds, duUses du_binds,
- emptyNameSet, L loc (LetStmt (HsValBinds binds')))]
+ -- fixities and unused are handled above in rnRecStmtsAndThen
+ rnLocalValBindsRHS (mkNameSet all_bndrs) binds'
+ return [(duDefs du_binds, allUses du_binds,
+ emptyNameSet, L loc (LetStmt (HsValBinds binds')))]
-- no RecStmt case becuase they get flattened above when doing the LHSes
-rn_rec_stmt _ stmt@(L _ (RecStmt _ _ _ _ _)) _
+rn_rec_stmt _ stmt@(L _ (RecStmt {})) _
= pprPanic "rn_rec_stmt: RecStmt" (ppr stmt)
-rn_rec_stmt _ 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
+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
+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)
+rn_rec_stmts bndrs stmts = mapM (uncurry (rn_rec_stmt bndrs)) stmts `thenM` \ segs_s ->
+ return (concat segs_s)
---------------------------------------------
addFwdRefs :: [Segment a] -> [Segment a]
----------------------------------------------------
-segsToStmts :: [Segment [LStmt Name]]
+segsToStmts :: Stmt Name -- A RecStmt with the SyntaxOps filled in
+ -> [Segment [LStmt Name]]
-> FreeVars -- Free vars used 'later'
-> ([LStmt Name], FreeVars)
-segsToStmts [] fvs_later = ([], fvs_later)
-segsToStmts ((defs, uses, fwds, ss) : segs) fvs_later
+segsToStmts _ [] fvs_later = ([], fvs_later)
+segsToStmts empty_rec_stmt ((defs, uses, fwds, ss) : segs) fvs_later
= ASSERT( not (null ss) )
(new_stmt : later_stmts, later_uses `plusFV` uses)
where
- (later_stmts, later_uses) = segsToStmts segs fvs_later
+ (later_stmts, later_uses) = segsToStmts empty_rec_stmt segs fvs_later
new_stmt | non_rec = head ss
- | otherwise = L (getLoc (head ss)) $
- RecStmt ss (nameSetToList used_later) (nameSetToList fwds)
- [] emptyLHsBinds
- where
- non_rec = isSingleton ss && isEmptyNameSet fwds
- used_later = defs `intersectNameSet` later_uses
+ | otherwise = L (getLoc (head ss)) rec_stmt
+ rec_stmt = empty_rec_stmt { recS_stmts = ss
+ , recS_later_ids = nameSetToList used_later
+ , recS_rec_ids = nameSetToList fwds }
+ non_rec = isSingleton ss && isEmptyNameSet fwds
+ used_later = defs `intersectNameSet` later_uses
-- The ones needed after the RecStmt
\end{code}
\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)
-- Return an expression for (assertError "Foo.hs:27")
%************************************************************************
\begin{code}
+checkEmptyStmts :: HsStmtContext Name -> RnM ()
+-- We've seen an empty sequence of Stmts... is that ok?
+checkEmptyStmts ctxt
+ = unless (okEmpty ctxt) (addErr (emptyErr ctxt))
+
+okEmpty :: HsStmtContext Name -> Bool
+okEmpty (PatGuard {}) = True
+okEmpty _ = False
+
+emptyErr :: HsStmtContext Name -> SDoc
+emptyErr (ParStmtCtxt {}) = ptext (sLit "Empty statement group in parallel comprehension")
+emptyErr (TransformStmtCtxt {}) = ptext (sLit "Empty statement group preceding 'group' or 'then'")
+emptyErr ctxt = ptext (sLit "Empty") <+> pprStmtContext ctxt
----------------------
-- 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
+checkStmt :: HsStmtContext Name
+ -> Bool -- True <=> this is the last Stmt in the sequence
+ -> LStmt RdrName
+ -> RnM ()
+checkStmt ctxt is_last (L _ stmt)
+ = do { dflags <- getDOpts
+ ; case okStmt dflags ctxt is_last stmt of
+ Nothing -> return ()
+ Just extra -> addErr (msg $$ extra) }
where
- msg = ptext (sLit "Illegal 'rec' stmt in") <+> pprStmtContext ctxt
+ msg = sep [ ptext (sLit "Unexpected") <+> pprStmtCat stmt <+> ptext (sLit "statement")
+ , ptext (sLit "in") <+> pprAStmtContext ctxt ]
+
+pprStmtCat :: Stmt a -> SDoc
+pprStmtCat (TransformStmt {}) = ptext (sLit "transform")
+pprStmtCat (GroupStmt {}) = ptext (sLit "group")
+pprStmtCat (LastStmt {}) = ptext (sLit "return expression")
+pprStmtCat (ExprStmt {}) = ptext (sLit "exprssion")
+pprStmtCat (BindStmt {}) = ptext (sLit "binding")
+pprStmtCat (LetStmt {}) = ptext (sLit "let")
+pprStmtCat (RecStmt {}) = ptext (sLit "rec")
+pprStmtCat (ParStmt {}) = ptext (sLit "parallel")
+
+------------
+isOK, notOK :: Maybe SDoc
+isOK = Nothing
+notOK = Just empty
+
+okStmt, okDoStmt, okCompStmt :: DynFlags -> HsStmtContext Name -> Bool
+ -> Stmt RdrName -> Maybe SDoc
+-- Return Nothing if OK, (Just extra) if not ok
+-- The "extra" is an SDoc that is appended to an generic error message
+okStmt _ (PatGuard {}) _ stmt
+ = case stmt of
+ ExprStmt {} -> isOK
+ BindStmt {} -> isOK
+ LetStmt {} -> isOK
+ _ -> notOK
+
+okStmt dflags (ParStmtCtxt ctxt) _ stmt
+ = case stmt of
+ LetStmt (HsIPBinds {}) -> notOK
+ _ -> okStmt dflags ctxt False stmt
+ -- NB: is_last=False in recursive
+ -- call; the branches of of a Par
+ -- not finish with a LastStmt
+
+okStmt dflags (TransformStmtCtxt ctxt) _ stmt
+ = okStmt dflags ctxt False stmt
+
+okStmt dflags ctxt is_last stmt
+ | isDoExpr ctxt = okDoStmt dflags ctxt is_last stmt
+ | isListCompExpr ctxt = okCompStmt dflags ctxt is_last stmt
+ | otherwise = pprPanic "okStmt" (pprStmtContext ctxt)
+
+----------------
+okDoStmt dflags ctxt is_last stmt
+ | is_last
+ = case stmt of
+ LastStmt {} -> isOK
+ _ -> Just (ptext (sLit "The last statement in") <+> pprAStmtContext ctxt
+ <+> ptext (sLit "must be an expression"))
+
+ | otherwise
+ = case stmt of
+ RecStmt {}
+ | Opt_DoRec `xopt` dflags -> isOK
+ | otherwise -> Just (ptext (sLit "Use -XDoRec"))
+ BindStmt {} -> isOK
+ LetStmt {} -> isOK
+ ExprStmt {} -> isOK
+ _ -> notOK
+
+
+----------------
+okCompStmt dflags _ is_last stmt
+ | is_last
+ = case stmt of
+ LastStmt {} -> Nothing
+ _ -> pprPanic "Unexpected stmt" (ppr stmt) -- Not a user error
+
+ | otherwise
+ = case stmt of
+ BindStmt {} -> isOK
+ LetStmt {} -> isOK
+ ExprStmt {} -> isOK
+ ParStmt {}
+ | Opt_ParallelListComp `xopt` dflags -> isOK
+ | otherwise -> Just (ptext (sLit "Use -XParallelListComp"))
+ TransformStmt {}
+ | Opt_TransformListComp `xopt` dflags -> isOK
+ | otherwise -> Just (ptext (sLit "Use -XTransformListComp"))
+ GroupStmt {}
+ | Opt_TransformListComp `xopt` dflags -> isOK
+ | otherwise -> Just (ptext (sLit "Use -XTransformListComp"))
+ LastStmt {} -> notOK
+ RecStmt {} -> notOK
---------
-checkParStmt :: HsStmtContext Name -> RnM ()
-checkParStmt _
- = do { parallel_list_comp <- doptM Opt_ParallelListComp
- ; checkErr parallel_list_comp msg }
+checkTupleSection :: [HsTupArg RdrName] -> RnM ()
+checkTupleSection args
+ = do { tuple_section <- xoptM Opt_TupleSections
+ ; checkErr (all tupArgPresent args || tuple_section) msg }
where
- msg = ptext (sLit "Illegal parallel list comprehension: use -XParallelListComp")
+ msg = ptext (sLit "Illegal tuple section: use -XTupleSections")
---------
-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"))
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