import {-# SOURCE #-} TcSplice( runQuasiQuoteExpr )
#endif /* GHCI */
-import RnSource ( rnSrcDecls )
-import RnBinds ( rnLocalBindsAndThen, rnValBindsLHS, rnValBindsRHS,
+import RnSource ( rnSrcDecls, findSplice )
+import RnBinds ( rnLocalBindsAndThen, rnLocalValBindsLHS, rnLocalValBindsRHS,
rnMatchGroup, makeMiniFixityEnv)
import HsSyn
import TcRnMonad
-import TcEnv ( thRnBrack )
+import TcEnv ( thRnBrack, getHetMetLevel )
import RnEnv
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 Var ( TyVar, varName )
import Name
import NameSet
import RdrName
import LoadIface ( loadInterfaceForName )
import UniqSet
-import List ( nub )
+import Data.List
import Util ( isSingleton )
import ListSetOps ( removeDups )
-import Maybes ( expectJust )
import Outputable
import SrcLoc
import FastString
-
-import List ( unzip4 )
+import Control.Monad
\end{code}
Variables. We look up the variable and return the resulting name.
\begin{code}
+
+-- during the renamer phase we only care about the length of the
+-- current HetMet level; the actual tyvars don't
+-- matter, so we use bottoms for them
+dummyTyVar :: TyVar
+dummyTyVar = error "tried to force RnExpr.dummyTyVar"
+
rnLExpr :: LHsExpr RdrName -> RnM (LHsExpr Name, FreeVars)
rnLExpr = wrapLocFstM rnExpr
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
rnLExpr arg `thenM` \ (arg',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) ->
mkNegAppRn e' neg_name `thenM` \ final_e ->
return (final_e, fv_e `plusFV` fv_neg)
+rnExpr (HsHetMetBrak c e)
+ = do { (e', fv_e) <- updLclEnv (\x -> x { tcl_hetMetLevel = dummyTyVar:(tcl_hetMetLevel x) }) $ rnLExpr e
+ ; return (HsHetMetBrak c e', fv_e)
+ }
+rnExpr (HsHetMetEsc c t e)
+ = do { (e', fv_e) <- updLclEnv (\x -> x { tcl_hetMetLevel = tail (tcl_hetMetLevel x) }) $ rnLExpr e
+ ; return (HsHetMetEsc c t e', fv_e)
+ }
+rnExpr (HsHetMetCSP c e)
+ = do { (e', fv_e) <- updLclEnv (\x -> x { tcl_hetMetLevel = tail (tcl_hetMetLevel x) }) $ rnLExpr e
+ ; return (HsHetMetCSP c e', fv_e)
+ }
+
+
+
------------------------------------------
-- Template Haskell extensions
-- Don't ifdef-GHCI them because we want to fail gracefully
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) ->
- return (expr'', fvs_qq `plusFV` fvs_expr)
+ = runQuasiQuoteExpr qq `thenM` \ (L _ expr') ->
+ rnExpr expr'
#endif /* GHCI */
---------------------------------------------
return (HsLet binds' expr', fvExpr)
rnExpr (HsDo do_or_lc stmts body _)
- = do { ((stmts', body'), fvs) <- rnStmts do_or_lc stmts $
+ = do { ((stmts', body'), fvs) <- rnStmts do_or_lc stmts $ \ _ ->
rnLExpr body
; return (HsDo do_or_lc stmts' body' placeHolderType, fvs) }
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) ->
- return (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) ->
\begin{code}
rnExpr (HsProc pat body)
= newArrowScope $
- rnPatsAndThen_LocalRightwards ProcExpr [pat] $ \ [pat'] ->
+ rnPat ProcExpr pat $ \ pat' ->
rnCmdTop body `thenM` \ (body',fvBody) ->
return (HsProc pat' body', fvBody)
-- 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) ->
%************************************************************************
%* *
+ 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
%* *
%************************************************************************
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)
= 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 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
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 (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}
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
+ ; 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
; return (VarBr name, unitFV 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)
+rnStmts :: HsStmtContext Name -> [LStmt RdrName]
+ -> ([Name] -> RnM (thing, FreeVars))
-> RnM (([LStmt Name], thing), FreeVars)
--- Used for cases *other* than recursive mdo
--- Implements nested scopes
+-- Variables bound by the Stmts, and mentioned in thing_inside,
+-- do not appear in the result FreeVars
+--
+-- Renaming a single RecStmt can give a sequence of smaller Stmts
-rnNormalStmts _ [] thing_inside
- = do { (thing, fvs) <- thing_inside
- ; return (([],thing), fvs) }
+rnStmts _ [] thing_inside
+ = do { (res, fvs) <- thing_inside []
+ ; return (([], res), 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 ctxt (stmt@(L loc _) : stmts) thing_inside
+ = do { ((stmts1, (stmts2, thing)), fvs)
+ <- setSrcSpan loc $
+ rnStmt ctxt stmt $ \ bndrs1 ->
+ rnStmts ctxt stmts $ \ 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 _ (ExprStmt expr _ _) thing_inside
+rnStmt _ (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),
+ ; (thing, fvs2) <- thing_inside []
+ ; return (([L loc (ExprStmt expr' then_op placeHolderType)], thing),
fv_expr `plusFV` fvs1 `plusFV` fvs2) }
-rnStmt ctxt (BindStmt pat expr _ _) thing_inside
+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
+rnStmt ctxt (L loc (LetStmt binds)) thing_inside
= do { checkLetStmt ctxt binds
; rnLocalBindsAndThen binds $ \binds' -> do
- { (thing, fvs) <- thing_inside
- ; return ((LetStmt binds', thing), fvs) } }
+ { (thing, fvs) <- thing_inside (collectLocalBinders binds')
+ ; return (([L loc (LetStmt binds')], thing), fvs) } }
-rnStmt ctxt (RecStmt rec_stmts _ _ _ _) thing_inside
+rnStmt ctxt (L _ (RecStmt { recS_stmts = rec_stmts })) thing_inside
= do { checkRecStmt ctxt
- ; rn_rec_stmts_and_then rec_stmts $ \ segs -> do
- { (thing, fvs) <- 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.)
+ ; 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
+
+ -- 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 { checkParStmt ctxt
; ((segs', thing), fvs) <- rnParallelStmts (ParStmtCtxt ctxt) segs thing_inside
- ; return ((ParStmt segs', thing), fvs) }
+ ; return (([L loc (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)
+rnStmt ctxt (L loc (TransformStmt stmts _ using by)) thing_inside
+ = do { checkTransformStmt ctxt
- 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)
+ ; (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) }
+
+ ; return (([L loc (TransformStmt stmts' used_bndrs using' by')], thing),
+ fvs1 `plusFV` fvs2) }
-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)
+rnStmt ctxt (L loc (GroupStmt stmts _ by using)) thing_inside
+ = do { checkTransformStmt ctxt
- -- 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'
-
- mapM_ 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:")
+ -- Rename the 'using' expression in the context before the transform is begun
+ ; (using', fvs1) <- case using of
+ Left e -> do { (e', fvs) <- rnLExpr e; return (Left e', fvs) }
+ Right _ -> do { (e', fvs) <- lookupSyntaxName groupWithName
+ ; return (Right 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) }
+
+ ; let all_fvs = fvs1 `plusFV` fvs2
+ 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 stmts' bndr_map by' using')], 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
= 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
= 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
- mapM (rn_rec_stmt_lhs fix_env) stmts `thenM` \ ls -> return (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
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'
- return [(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)) _
----------------------------------------------------
-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}
---------
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
+checkRecStmt MDoExpr = return () -- Recursive stmt ok in 'mdo'
+checkRecStmt DoExpr = return () -- and in 'do'
+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
+ = do { parallel_list_comp <- xoptM 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
+ = do { transform_list_comp <- xoptM Opt_TransformListComp
; checkErr transform_list_comp msg }
where
msg = ptext (sLit "Illegal transform or grouping list comprehension: use -XTransformListComp")
---------
checkTupleSection :: [HsTupArg RdrName] -> RnM ()
checkTupleSection args
- = do { tuple_section <- doptM Opt_TupleSections
+ = do { tuple_section <- xoptM Opt_TupleSections
; checkErr (all tupArgPresent args || tuple_section) msg }
where
msg = ptext (sLit "Illegal tuple section: use -XTupleSections")
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