import RnHsSyn
import TcRnMonad
import RnEnv
+import RnNames ( importsFromLocalDecls )
import RnTypes ( rnHsTypeFVs, rnPat, litFVs, rnOverLit, rnPatsAndThen,
- dupFieldErr, precParseErr, sectionPrecErr, patSigErr )
+ dupFieldErr, precParseErr, sectionPrecErr, patSigErr, checkTupSize )
import CmdLineOpts ( DynFlag(..), opt_IgnoreAsserts )
import BasicTypes ( Fixity(..), FixityDirection(..), IPName(..),
defaultFixity, negateFixity, compareFixity )
foldrName, buildName,
cCallableClassName, cReturnableClassName,
enumClassName,
+ loopAName, choiceAName, appAName, arrAName, composeAName, firstAName,
splitName, fstName, sndName, ioDataConName,
replicatePName, mapPName, filterPName,
crossPName, zipPName, toPName,
enumFromToPName, enumFromThenToPName, assertErrorName,
- negateName, qTyConName, monadNames, mfixName )
-import RdrName ( RdrName )
+ negateName, monadNames, mfixName )
import Name ( Name, nameOccName )
import NameSet
import UnicodeUtil ( stringToUtf8 )
import UniqFM ( isNullUFM )
import UniqSet ( emptyUniqSet )
-import Util ( isSingleton )
+import Util ( isSingleton, mapAndUnzip )
import List ( intersectBy, unzip4 )
import ListSetOps ( removeDups )
import Outputable
+import SrcLoc ( noSrcLoc )
import FastString
\end{code}
************************************************************************
\begin{code}
-rnMatch :: HsMatchContext RdrName -> RdrNameMatch -> RnM (RenamedMatch, FreeVars)
+rnMatch :: HsMatchContext Name -> RdrNameMatch -> RnM (RenamedMatch, FreeVars)
rnMatch ctxt match@(Match pats maybe_rhs_sig grhss)
= addSrcLoc (getMatchLoc match) $
-- Deal with the rhs type signature
- bindPatSigTyVars rhs_sig_tys $
+ bindPatSigTyVarsFV rhs_sig_tys $
doptM Opt_GlasgowExts `thenM` \ opt_GlasgowExts ->
(case maybe_rhs_sig of
Nothing -> returnM (Nothing, emptyFVs)
-- Now the main event
rnPatsAndThen ctxt pats $ \ pats' ->
- rnGRHSs grhss `thenM` \ (grhss', grhss_fvs) ->
+ rnGRHSs ctxt grhss `thenM` \ (grhss', grhss_fvs) ->
returnM (Match pats' maybe_rhs_sig' grhss', grhss_fvs `plusFV` ty_fvs)
- -- The bindPatSigTyVars and rnPatsAndThen will remove the bound FVs
+ -- The bindPatSigTyVarsFV and rnPatsAndThen will remove the bound FVs
where
rhs_sig_tys = case maybe_rhs_sig of
Nothing -> []
%************************************************************************
\begin{code}
-rnGRHSs :: RdrNameGRHSs -> RnM (RenamedGRHSs, FreeVars)
+rnGRHSs :: HsMatchContext Name -> RdrNameGRHSs -> RnM (RenamedGRHSs, FreeVars)
-rnGRHSs (GRHSs grhss binds _)
+rnGRHSs ctxt (GRHSs grhss binds _)
= rnBindsAndThen binds $ \ binds' ->
- mapFvRn rnGRHS grhss `thenM` \ (grhss', fvGRHSs) ->
+ mapFvRn (rnGRHS ctxt) grhss `thenM` \ (grhss', fvGRHSs) ->
returnM (GRHSs grhss' binds' placeHolderType, fvGRHSs)
-rnGRHS (GRHS guarded locn)
+rnGRHS ctxt (GRHS guarded locn)
= addSrcLoc locn $
doptM Opt_GlasgowExts `thenM` \ opt_GlasgowExts ->
checkM (opt_GlasgowExts || is_standard_guard guarded)
(addWarn (nonStdGuardErr guarded)) `thenM_`
- rnStmts PatGuard guarded `thenM` \ (guarded', fvs) ->
+ rnStmts (PatGuard ctxt) guarded `thenM` \ (guarded', fvs) ->
returnM (GRHS guarded' locn, fvs)
where
-- Standard Haskell 1.4 guards are just a single boolean
= lookupOccRn v `thenM` \ name ->
if name `hasKey` assertIdKey && not opt_IgnoreAsserts then
-- We expand it to (GHC.Err.assertError location_string)
- mkAssertErrorExpr
+ mkAssertErrorExpr `thenM` \ (e, fvs) ->
+ returnM (e, fvs `addOneFV` name)
+ -- Keep 'assert' as a free var, to ensure it's not reported as unused!
else
-- The normal case. Even if the Id was 'assert', if we are
-- ignoring assertions we leave it as GHC.Base.assert;
returnM (HsPar e', fvs_e)
-- Template Haskell extensions
-rnExpr (HsBracket br_body)
- = checkGHCI (thErr "bracket") `thenM_`
- rnBracket br_body `thenM` \ (body', fvs_e) ->
- returnM (HsBracket body', fvs_e `addOneFV` qTyConName)
- -- We use the Q tycon as a proxy to haul in all the smart
- -- constructors; see the hack in RnIfaces
-
-rnExpr (HsSplice n e)
- = checkGHCI (thErr "splice") `thenM_`
- getSrcLocM `thenM` \ loc ->
- newLocalsRn [(n,loc)] `thenM` \ [n'] ->
- rnExpr e `thenM` \ (e', fvs_e) ->
- returnM (HsSplice n' e', fvs_e)
+-- Don't ifdef-GHCI them because we want to fail gracefully
+-- (not with an rnExpr crash) in a stage-1 compiler.
+rnExpr e@(HsBracket br_body loc)
+ = addSrcLoc loc $
+ checkTH e "bracket" `thenM_`
+ rnBracket br_body `thenM` \ (body', fvs_e) ->
+ returnM (HsBracket body' loc, fvs_e `plusFV` thProxyName)
+
+rnExpr e@(HsSplice n splice loc)
+ = addSrcLoc loc $
+ checkTH e "splice" `thenM_`
+ newLocalsRn [(n,loc)] `thenM` \ [n'] ->
+ rnExpr splice `thenM` \ (splice', fvs_e) ->
+ returnM (HsSplice n' splice' loc, fvs_e `plusFV` thProxyName)
+
+rnExpr e@(HsReify (Reify flavour name))
+ = checkTH e "reify" `thenM_`
+ lookupGlobalOccRn name `thenM` \ name' ->
+ -- For now, we can only reify top-level things
+ returnM (HsReify (Reify flavour name'), unitFV name' `plusFV` thProxyName)
rnExpr section@(SectionL expr op)
= rnExpr expr `thenM` \ (expr', fvs_expr) ->
cReturnableClassName,
ioDataConName])
+rnExpr (HsCoreAnn ann expr)
+ = rnExpr expr `thenM` \ (expr', fvs_expr) ->
+ returnM (HsCoreAnn ann expr', fvs_expr)
+
rnExpr (HsSCC lbl expr)
= rnExpr expr `thenM` \ (expr', fvs_expr) ->
returnM (HsSCC lbl expr', fvs_expr)
rnExpr expr `thenM` \ (expr',fvExpr) ->
returnM (HsLet binds' expr', fvExpr)
-rnExpr (HsWith expr binds is_with)
- = warnIf is_with withWarning `thenM_`
- rnExpr expr `thenM` \ (expr',fvExpr) ->
- rnIPBinds binds `thenM` \ (binds',fvBinds) ->
- returnM (HsWith expr' binds' is_with, fvExpr `plusFV` fvBinds)
-
rnExpr e@(HsDo do_or_lc stmts _ _ src_loc)
= addSrcLoc src_loc $
rnStmts do_or_lc stmts `thenM` \ (stmts', fvs) ->
-- Check the statement list ends in an expression
case last stmts' of {
ResultStmt _ _ -> returnM () ;
- _ -> addErr (doStmtListErr "do" e)
+ _ -> addErr (doStmtListErr do_or_lc e)
} `thenM_`
-- Generate the rebindable syntax for the monad
- mapAndUnzipM lookupSyntaxName
- (syntax_names do_or_lc) `thenM` \ (monad_names', monad_fvs) ->
+ lookupSyntaxNames syntax_names `thenM` \ (syntax_names', monad_fvs) ->
- returnM (HsDo do_or_lc stmts' monad_names' placeHolderType src_loc,
- fvs `plusFV` implicit_fvs do_or_lc `plusFV` plusFVs monad_fvs)
+ returnM (HsDo do_or_lc stmts' syntax_names' placeHolderType src_loc,
+ fvs `plusFV` implicit_fvs do_or_lc `plusFV` monad_fvs)
where
implicit_fvs PArrComp = mkFVs [replicatePName, mapPName, filterPName, crossPName, zipPName]
implicit_fvs ListComp = mkFVs [foldrName, buildName]
implicit_fvs DoExpr = emptyFVs
implicit_fvs MDoExpr = emptyFVs
- syntax_names DoExpr = monadNames
- syntax_names MDoExpr = monadNames ++ [mfixName]
- syntax_names other = []
+ syntax_names = case do_or_lc of
+ DoExpr -> monadNames
+ MDoExpr -> monadNames ++ [mfixName]
+ other -> []
rnExpr (ExplicitList _ exps)
= rnExprs exps `thenM` \ (exps', fvs) ->
returnM (ExplicitPArr placeHolderType exps',
fvs `addOneFV` toPName `addOneFV` parrTyCon_name)
-rnExpr (ExplicitTuple exps boxity)
- = rnExprs exps `thenM` \ (exps', fvs) ->
+rnExpr e@(ExplicitTuple exps boxity)
+ = checkTupSize tup_size `thenM_`
+ rnExprs exps `thenM` \ (exps', fvs) ->
returnM (ExplicitTuple exps' boxity, fvs `addOneFV` tycon_name)
where
- tycon_name = tupleTyCon_name boxity (length exps)
+ tup_size = length exps
+ tycon_name = tupleTyCon_name boxity tup_size
rnExpr (RecordCon con_id rbinds)
= lookupOccRn con_id `thenM` \ conname ->
%************************************************************************
%* *
+ Arrow notation
+%* *
+%************************************************************************
+
+\begin{code}
+rnExpr (HsProc pat body src_loc)
+ = addSrcLoc src_loc $
+ rnPatsAndThen ProcExpr [pat] $ \ [pat'] ->
+ rnCmdTop body `thenM` \ (body',fvBody) ->
+ returnM (HsProc pat' body' src_loc, fvBody)
+
+rnExpr (HsArrApp arrow arg _ ho rtl srcloc)
+ = rnExpr arrow `thenM` \ (arrow',fvArrow) ->
+ rnExpr arg `thenM` \ (arg',fvArg) ->
+ returnM (HsArrApp arrow' arg' placeHolderType ho rtl srcloc,
+ fvArrow `plusFV` fvArg)
+
+-- infix form
+rnExpr (HsArrForm op (Just _) [arg1, arg2] srcloc)
+ = rnExpr op `thenM` \ (op'@(HsVar op_name),fv_op) ->
+ rnCmdTop arg1 `thenM` \ (arg1',fv_arg1) ->
+ rnCmdTop arg2 `thenM` \ (arg2',fv_arg2) ->
+
+ -- Deal with fixity
+
+ lookupFixityRn op_name `thenM` \ fixity ->
+ mkOpFormRn arg1' op' fixity arg2' `thenM` \ final_e ->
+
+ returnM (final_e,
+ fv_arg1 `plusFV` fv_op `plusFV` fv_arg2)
+
+rnExpr (HsArrForm op fixity cmds srcloc)
+ = rnExpr op `thenM` \ (op',fvOp) ->
+ rnCmdArgs cmds `thenM` \ (cmds',fvCmds) ->
+ returnM (HsArrForm op' fixity cmds' srcloc,
+ fvOp `plusFV` fvCmds)
+
+---------------------------
+-- Deal with fixity (cf mkOpAppRn for the method)
+
+mkOpFormRn :: RenamedHsCmdTop -- Left operand; already rearranged
+ -> RenamedHsExpr -> Fixity -- Operator and fixity
+ -> RenamedHsCmdTop -- Right operand (not an infix)
+ -> RnM RenamedHsCmd
+
+---------------------------
+-- (e11 `op1` e12) `op2` e2
+mkOpFormRn a1@(HsCmdTop (HsArrForm op1 (Just fix1) [a11,a12] loc1) _ _ _) op2 fix2 a2
+ | nofix_error
+ = addErr (precParseErr (ppr_op op1,fix1) (ppr_op op2,fix2)) `thenM_`
+ returnM (HsArrForm op2 (Just fix2) [a1, a2] loc1)
+
+ | associate_right
+ = mkOpFormRn a12 op2 fix2 a2 `thenM` \ new_c ->
+ returnM (HsArrForm op1 (Just fix1)
+ [a11, HsCmdTop new_c [] placeHolderType []] loc1)
+ where
+ (nofix_error, associate_right) = compareFixity fix1 fix2
+
+---------------------------
+-- Default case
+mkOpFormRn arg1 op fix arg2 -- Default case, no rearrangment
+ = returnM (HsArrForm op (Just fix) [arg1, arg2] noSrcLoc)
+
+\end{code}
+
+
+%************************************************************************
+%* *
+ Arrow commands
+%* *
+%************************************************************************
+
+\begin{code}
+rnCmdArgs [] = returnM ([], emptyFVs)
+rnCmdArgs (arg:args)
+ = rnCmdTop arg `thenM` \ (arg',fvArg) ->
+ rnCmdArgs args `thenM` \ (args',fvArgs) ->
+ returnM (arg':args', fvArg `plusFV` fvArgs)
+
+rnCmdTop (HsCmdTop cmd _ _ _)
+ = rnExpr (convertOpFormsCmd cmd) `thenM` \ (cmd', fvCmd) ->
+ let
+ cmd_names = [arrAName, composeAName, firstAName] ++
+ nameSetToList (methodNamesCmd cmd')
+ in
+ -- Generate the rebindable syntax for the monad
+ lookupSyntaxNames cmd_names `thenM` \ (cmd_names', cmd_fvs) ->
+
+ returnM (HsCmdTop cmd' [] placeHolderType cmd_names',
+ fvCmd `plusFV` cmd_fvs)
+
+---------------------------------------------------
+-- convert OpApp's in a command context to HsArrForm's
+
+convertOpFormsCmd :: HsCmd id -> HsCmd id
+
+convertOpFormsCmd (HsApp c e) = HsApp (convertOpFormsCmd c) e
+
+convertOpFormsCmd (HsLam match) = HsLam (convertOpFormsMatch match)
+
+convertOpFormsCmd (OpApp c1 op fixity c2)
+ = let
+ arg1 = HsCmdTop (convertOpFormsCmd c1) [] placeHolderType []
+ arg2 = HsCmdTop (convertOpFormsCmd c2) [] placeHolderType []
+ in
+ HsArrForm op (Just fixity) [arg1, arg2] noSrcLoc
+
+convertOpFormsCmd (HsPar c) = HsPar (convertOpFormsCmd c)
+
+convertOpFormsCmd (HsCase exp matches locn)
+ = HsCase exp (map convertOpFormsMatch matches) locn
+
+convertOpFormsCmd (HsIf exp c1 c2 locn)
+ = HsIf exp (convertOpFormsCmd c1) (convertOpFormsCmd c2) locn
+
+convertOpFormsCmd (HsLet binds cmd)
+ = HsLet binds (convertOpFormsCmd cmd)
+
+convertOpFormsCmd (HsDo ctxt stmts ids ty locn)
+ = HsDo ctxt (map convertOpFormsStmt stmts) ids ty locn
+
+-- Anything else is unchanged. This includes HsArrForm (already done),
+-- things with no sub-commands, and illegal commands (which will be
+-- caught by the type checker)
+convertOpFormsCmd c = c
+
+convertOpFormsStmt (BindStmt pat cmd locn)
+ = BindStmt pat (convertOpFormsCmd cmd) locn
+convertOpFormsStmt (ResultStmt cmd locn)
+ = ResultStmt (convertOpFormsCmd cmd) locn
+convertOpFormsStmt (ExprStmt cmd ty locn)
+ = ExprStmt (convertOpFormsCmd cmd) ty locn
+convertOpFormsStmt (RecStmt stmts lvs rvs es)
+ = RecStmt (map convertOpFormsStmt stmts) lvs rvs es
+convertOpFormsStmt stmt = stmt
+
+convertOpFormsMatch (Match pat mty grhss)
+ = Match pat mty (convertOpFormsGRHSs grhss)
+
+convertOpFormsGRHSs (GRHSs grhss binds ty)
+ = GRHSs (map convertOpFormsGRHS grhss) binds ty
+
+convertOpFormsGRHS (GRHS stmts locn)
+ = let
+ (ResultStmt cmd locn') = last stmts
+ in
+ GRHS (init stmts ++ [ResultStmt (convertOpFormsCmd cmd) locn']) locn
+
+---------------------------------------------------
+type CmdNeeds = FreeVars -- Only inhabitants are
+ -- appAName, choiceAName, loopAName
+
+-- find what methods the Cmd needs (loop, choice, apply)
+methodNamesCmd :: HsCmd Name -> CmdNeeds
+
+methodNamesCmd cmd@(HsArrApp _arrow _arg _ HsFirstOrderApp _rtl _srcloc)
+ = emptyFVs
+methodNamesCmd cmd@(HsArrApp _arrow _arg _ HsHigherOrderApp _rtl _srcloc)
+ = unitFV appAName
+methodNamesCmd cmd@(HsArrForm {}) = emptyFVs
+
+methodNamesCmd (HsPar c) = methodNamesCmd c
+
+methodNamesCmd (HsIf p c1 c2 loc)
+ = methodNamesCmd c1 `plusFV` methodNamesCmd c2 `addOneFV` choiceAName
+
+methodNamesCmd (HsLet b c) = methodNamesCmd c
+
+methodNamesCmd (HsDo sc stmts rbs ty loc) = methodNamesStmts stmts
+
+methodNamesCmd (HsApp c e) = methodNamesCmd c
+
+methodNamesCmd (HsLam match) = methodNamesMatch match
+
+methodNamesCmd (HsCase scrut matches loc)
+ = plusFVs (map methodNamesMatch matches) `addOneFV` choiceAName
+
+methodNamesCmd other = 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 (Match pats sig_ty grhss) = methodNamesGRHSs grhss
+
+-------------------------------------------------
+methodNamesGRHSs (GRHSs grhss binds ty) = plusFVs (map methodNamesGRHS grhss)
+
+-------------------------------------------------
+methodNamesGRHS (GRHS stmts loc) = methodNamesStmt (last stmts)
+
+---------------------------------------------------
+methodNamesStmts stmts = plusFVs (map methodNamesStmt stmts)
+
+---------------------------------------------------
+methodNamesStmt (ResultStmt cmd loc) = methodNamesCmd cmd
+methodNamesStmt (ExprStmt cmd ty loc) = methodNamesCmd cmd
+methodNamesStmt (BindStmt pat cmd loc) = methodNamesCmd cmd
+methodNamesStmt (RecStmt stmts lvs rvs es)
+ = 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
+ -- here so we just do what's convenient
+\end{code}
+
+
+%************************************************************************
+%* *
Arithmetic sequences
%* *
%************************************************************************
%************************************************************************
%* *
-\subsubsection{@rnIPBinds@s: in implicit parameter bindings} *
-%* *
-%************************************************************************
-
-\begin{code}
-rnIPBinds [] = returnM ([], emptyFVs)
-rnIPBinds ((n, expr) : binds)
- = newIPName n `thenM` \ name ->
- rnExpr expr `thenM` \ (expr',fvExpr) ->
- rnIPBinds binds `thenM` \ (binds',fvBinds) ->
- returnM ((name, expr') : binds', fvExpr `plusFV` fvBinds)
-
-\end{code}
-
-%************************************************************************
-%* *
Template Haskell brackets
%* *
%************************************************************************
returnM (TypBr t', fvs)
where
doc = ptext SLIT("In a Template-Haskell quoted type")
-rnBracket (DecBr ds) = rnSrcDecls ds `thenM` \ (tcg_env, ds', fvs) ->
- -- Discard the tcg_env; it contains the extended global RdrEnv
- -- because there is no scope that these decls cover (yet!)
- returnM (DecBr ds', fvs)
+rnBracket (DecBr group)
+ = importsFromLocalDecls group `thenM` \ (rdr_env, avails) ->
+ -- Discard avails (not useful here)
+
+ updGblEnv (\gbl -> gbl { tcg_rdr_env = rdr_env `plusGlobalRdrEnv` tcg_rdr_env gbl }) $
+
+ rnSrcDecls group `thenM` \ (tcg_env, group', dus) ->
+ -- Discard the tcg_env; it contains only extra info about fixity
+
+ returnM (DecBr group', duUses dus `minusNameSet` duDefs dus)
\end{code}
%************************************************************************
%************************************************************************
\begin{code}
-rnStmts :: HsStmtContext
- -> [RdrNameStmt]
- -> RnM ([RenamedStmt], FreeVars)
+rnStmts :: HsStmtContext Name -> [RdrNameStmt] -> RnM ([RenamedStmt], FreeVars)
rnStmts MDoExpr stmts = rnMDoStmts stmts
rnStmts ctxt stmts = rnNormalStmts ctxt stmts
-rnNormalStmts :: HsStmtContext -> [RdrNameStmt] -> RnM ([RenamedStmt], FreeVars)
+rnNormalStmts :: HsStmtContext Name -> [RdrNameStmt] -> RnM ([RenamedStmt], FreeVars)
-- Used for cases *other* than recursive mdo
-- Implements nested scopes
+rnNormalStmts ctxt [] = returnM ([], emptyFVs)
+ -- Happens at the end of the sub-lists of a ParStmts
+
rnNormalStmts ctxt (ExprStmt expr _ src_loc : stmts)
= addSrcLoc src_loc $
rnExpr expr `thenM` \ (expr', fv_expr) ->
-- the rnPatsAndThen, but it does not matter
rnNormalStmts ctxt (LetStmt binds : stmts)
- = rnBindsAndThen binds $ \ binds' ->
- rnNormalStmts ctxt stmts `thenM` \ (stmts', fvs) ->
- returnM (LetStmt binds' : stmts', fvs)
+ = checkErr (ok ctxt binds) (badIpBinds binds) `thenM_`
+ rnBindsAndThen binds ( \ binds' ->
+ rnNormalStmts ctxt stmts `thenM` \ (stmts', fvs) ->
+ returnM (LetStmt binds' : stmts', fvs))
+ where
+ -- We do not allow implicit-parameter bindings in a parallel
+ -- list comprehension. I'm not sure what it might mean.
+ ok (ParStmtCtxt _) (IPBinds _ _) = False
+ ok _ _ = True
rnNormalStmts ctxt (ParStmt stmtss : stmts)
- = mapFvRn (rnNormalStmts ctxt) stmtss `thenM` \ (stmtss', fv_stmtss) ->
+ = doptM Opt_GlasgowExts `thenM` \ opt_GlasgowExts ->
+ checkM opt_GlasgowExts parStmtErr `thenM_`
+ mapFvRn rn_branch stmtss `thenM` \ (stmtss', fv_stmtss) ->
let
- bndrss = map collectStmtsBinders stmtss'
+ bndrss :: [[Name]] -- NB: Name, not RdrName
+ bndrss = map collectStmtsBinders stmtss'
+ (bndrs, dups) = removeDups cmpByOcc (concat bndrss)
in
- foldlM checkBndrs [] bndrss `thenM` \ new_binders ->
- bindLocalNamesFV new_binders $
+ mappM dupErr dups `thenM` \ _ ->
+ bindLocalNamesFV bndrs $
-- Note: binders are returned in scope order, so one may
-- shadow the next; e.g. x <- xs; x <- ys
rnNormalStmts ctxt stmts `thenM` \ (stmts', fvs) ->
- returnM (ParStmtOut (bndrss `zip` stmtss') : stmts',
+
+ -- Cut down the exported binders to just the ones neede in the body
+ let
+ used_bndrs_s = map (filter (`elemNameSet` fvs)) bndrss
+ in
+ returnM (ParStmt (stmtss' `zip` used_bndrs_s) : stmts',
fv_stmtss `plusFV` fvs)
where
- checkBndrs all_bndrs bndrs
- = checkErr (null common) (err (head common)) `thenM_`
- returnM (bndrs ++ all_bndrs)
- where
- common = intersectBy eqOcc all_bndrs bndrs
+ rn_branch (stmts, _) = rnNormalStmts (ParStmtCtxt ctxt) stmts
- eqOcc n1 n2 = nameOccName n1 == nameOccName n2
- err v = ptext SLIT("Duplicate binding in parallel list comprehension for:")
- <+> quotes (ppr v)
+ cmpByOcc n1 n2 = nameOccName n1 `compare` nameOccName n2
+ dupErr (v:_) = addErr (ptext SLIT("Duplicate binding in parallel list comprehension for:")
+ <+> quotes (ppr v))
-rnMDoStmts stmts
- = bindLocalsRn doc (collectStmtsBinders stmts) $ \ _ ->
- mappM rn_mdo_stmt stmts `thenM` \ segs ->
- returnM (segsToStmts (glomSegments (addFwdRefs segs)))
+rnNormalStmts ctxt (RecStmt rec_stmts _ _ _ : stmts)
+ = bindLocalsRn doc (collectStmtsBinders rec_stmts) $ \ _ ->
+ rn_rec_stmts rec_stmts `thenM` \ segs ->
+ rnNormalStmts ctxt stmts `thenM` \ (stmts', 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
+ in
+ returnM (RecStmt rec_stmts' later_vars fwd_vars [] : stmts', uses `plusFV` fvs)
where
- doc = text "In a mdo-expression"
+ doc = text "In a recursive do statement"
+\end{code}
-type Defs = NameSet
-type Uses = NameSet -- Same as FreeVars really
+
+%************************************************************************
+%* *
+\subsubsection{mdo expressions}
+%* *
+%************************************************************************
+
+\begin{code}
type FwdRefs = NameSet
-type Segment = (Defs,
- Uses, -- May include defs
- FwdRefs, -- A subset of uses that are
+type Segment stmts = (Defs,
+ Uses, -- May include defs
+ FwdRefs, -- A subset of uses that are
-- (a) used before they are bound in this segment, or
-- (b) used here, and bound in subsequent segments
- [RenamedStmt])
+ stmts) -- Either Stmt or [Stmt]
+
----------------------------------------------------
-rn_mdo_stmt :: RdrNameStmt -> RnM Segment
+rnMDoStmts :: [RdrNameStmt] -> RnM ([RenamedStmt], FreeVars)
+rnMDoStmts stmts
+ = -- Step1: bring all the binders of the mdo into scope
+ -- Remember that this also removes the binders from the
+ -- finally-returned free-vars
+ bindLocalsRn doc (collectStmtsBinders stmts) $ \ _ ->
+
+ -- Step 2: Rename each individual stmt, making a
+ -- singleton segment. At this stage the FwdRefs field
+ -- isn't finished: it's empty for all except a BindStmt
+ -- for which it's the fwd refs within the bind itself
+ -- (This set may not be empty, because we're in a recursive
+ -- context.)
+ rn_rec_stmts stmts `thenM` \ segs ->
+ let
+ -- Step 3: Fill in the fwd refs.
+ -- The segments are all singletons, but their fwd-ref
+ -- field mentions all the things used by the segment
+ -- that are bound after their use
+ segs_w_fwd_refs = addFwdRefs segs
+
+ -- Step 4: Group together the segments to make bigger segments
+ -- Invariant: in the result, no segment uses a variable
+ -- bound in a later segment
+ grouped_segs = glomSegments segs_w_fwd_refs
+
+ -- Step 5: Turn the segments into Stmts
+ -- 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_w_fvs = segsToStmts grouped_segs
+ in
+ returnM stmts_w_fvs
+ where
+ doc = text "In a mdo-expression"
+
+
+----------------------------------------------------
+rn_rec_stmt :: RdrNameStmt -> RnM [Segment RenamedStmt]
+ -- 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_mdo_stmt (ExprStmt expr _ src_loc)
+rn_rec_stmt (ExprStmt expr _ src_loc)
= addSrcLoc src_loc (rnExpr expr) `thenM` \ (expr', fvs) ->
- returnM (emptyNameSet, fvs, emptyNameSet,
- [ExprStmt expr' placeHolderType src_loc])
+ returnM [(emptyNameSet, fvs, emptyNameSet,
+ ExprStmt expr' placeHolderType src_loc)]
-rn_mdo_stmt (ResultStmt expr src_loc)
+rn_rec_stmt (ResultStmt expr src_loc)
= addSrcLoc src_loc (rnExpr expr) `thenM` \ (expr', fvs) ->
- returnM (emptyNameSet, fvs, emptyNameSet,
- [ResultStmt expr' src_loc])
+ returnM [(emptyNameSet, fvs, emptyNameSet,
+ ResultStmt expr' src_loc)]
-rn_mdo_stmt (BindStmt pat expr src_loc)
+rn_rec_stmt (BindStmt pat expr src_loc)
= addSrcLoc src_loc $
rnExpr expr `thenM` \ (expr', fv_expr) ->
rnPat pat `thenM` \ (pat', fv_pat) ->
bndrs = mkNameSet (collectPatBinders pat')
fvs = fv_expr `plusFV` fv_pat
in
- returnM (bndrs, fvs, bndrs `intersectNameSet` fvs,
- [BindStmt pat' expr' src_loc])
+ returnM [(bndrs, fvs, bndrs `intersectNameSet` fvs,
+ BindStmt pat' expr' src_loc)]
-rn_mdo_stmt (LetStmt binds)
- = rnBinds binds `thenM` \ (binds', fv_binds) ->
- returnM (mkNameSet (collectHsBinders binds'),
- fv_binds, emptyNameSet, [LetStmt binds'])
+rn_rec_stmt (LetStmt binds)
+ = rnBinds binds `thenM` \ (binds', du_binds) ->
+ returnM [(duDefs du_binds, duUses du_binds,
+ emptyNameSet, LetStmt binds')]
-rn_mdo_stmt stmt@(ParStmt _) -- Syntactically illegal in mdo
- = pprPanic "rn_mdo_stmt" (ppr stmt)
+rn_rec_stmt (RecStmt stmts _ _ _) -- Flatten Rec inside Rec
+ = rn_rec_stmts stmts
+rn_rec_stmt stmt@(ParStmt _) -- Syntactically illegal in mdo
+ = pprPanic "rn_rec_stmt" (ppr stmt)
-addFwdRefs :: [Segment] -> [Segment]
+---------------------------------------------
+rn_rec_stmts :: [RdrNameStmt] -> RnM [Segment RenamedStmt]
+rn_rec_stmts stmts = mappM rn_rec_stmt stmts `thenM` \ segs_s ->
+ returnM (concat segs_s)
+
+
+---------------------------------------------
+addFwdRefs :: [Segment a] -> [Segment a]
-- So far the segments only have forward refs *within* the Stmt
-- (which happens for bind: x <- ...x...)
-- This function adds the cross-seg fwd ref info
addFwdRefs pairs
= fst (foldr mk_seg ([], emptyNameSet) pairs)
where
- mk_seg (defs, uses, fwds, stmts) (segs, seg_defs)
+ mk_seg (defs, uses, fwds, stmts) (segs, later_defs)
= (new_seg : segs, all_defs)
where
new_seg = (defs, uses, new_fwds, stmts)
- all_defs = seg_defs `unionNameSets` defs
- new_fwds = fwds `unionNameSets` (uses `intersectNameSet` seg_defs)
+ all_defs = later_defs `unionNameSets` defs
+ new_fwds = fwds `unionNameSets` (uses `intersectNameSet` later_defs)
-- Add the downstream fwd refs here
----------------------------------------------------
--- Breaking a recursive 'do' into segments
+-- Glomming the singleton segments of an mdo into
+-- minimal recursive groups.
+--
+-- At first I thought this was just strongly connected components, but
+-- there's an important constraint: the order of the stmts must not change.
--
-- Consider
-- mdo { x <- ...y...
-- z <- y
-- r <- x }
--
+-- Here, the first stmt mention 'y', which is bound in the third.
+-- But that means that the innocent second stmt (p <- z) gets caught
+-- up in the recursion. And that in turn means that the binding for
+-- 'z' has to be included... and so on.
+--
-- Start at the tail { r <- x }
-- Now add the next one { z <- y ; r <- x }
-- Now add one more { q <- x ; z <- y ; r <- x }
-- q <- x ; z <- y } ;
-- r <- x }
-glomSegments :: [Segment] -> [Segment]
+glomSegments :: [Segment RenamedStmt] -> [Segment [RenamedStmt]]
-glomSegments [seg] = [seg]
-glomSegments ((defs,uses,fwds,stmts) : segs)
+glomSegments [] = []
+glomSegments ((defs,uses,fwds,stmt) : segs)
-- Actually stmts will always be a singleton
= (seg_defs, seg_uses, seg_fwds, seg_stmts) : others
where
seg_defs = plusFVs ds `plusFV` defs
seg_uses = plusFVs us `plusFV` uses
seg_fwds = plusFVs fs `plusFV` fwds
- seg_stmts = stmts ++ concat ss
+ seg_stmts = stmt : concat ss
grab :: NameSet -- The client
- -> [Segment]
- -> ([Segment], -- Needed by the 'client'
- [Segment]) -- Not needed by the client
+ -> [Segment a]
+ -> ([Segment a], -- Needed by the 'client'
+ [Segment a]) -- Not needed by the client
-- The result is simply a split of the input
grab uses dus
= (reverse yeses, reverse noes)
----------------------------------------------------
-segsToStmts :: [Segment] -> ([RenamedStmt], FreeVars)
+segsToStmts :: [Segment [RenamedStmt]] -> ([RenamedStmt], FreeVars)
segsToStmts [] = ([], emptyFVs)
segsToStmts ((defs, uses, fwds, ss) : segs)
where
(later_stmts, later_uses) = segsToStmts segs
new_stmt | non_rec = head ss
- | otherwise = RecStmt rec_names ss
+ | otherwise = RecStmt ss (nameSetToList used_later) (nameSetToList fwds) []
where
- non_rec = isSingleton ss && isEmptyNameSet fwds
- rec_names = nameSetToList (fwds `plusFV` (defs `intersectNameSet` later_uses))
- -- The names for the fixpoint are
- -- (a) the ones needed after the RecStmt
- -- (b) the forward refs within the fixpoint
+ non_rec = isSingleton ss && isEmptyNameSet fwds
+ used_later = defs `intersectNameSet` later_uses
+ -- The ones needed after the RecStmt
\end{code}
%************************************************************************
= sep [ptext SLIT("Pattern syntax in expression context:"),
nest 4 (ppr e)]
-doStmtListErr name e
- = sep [quotes (text name) <+> ptext SLIT("statements must end in expression:"),
+doStmtListErr do_or_lc e
+ = sep [quotes (text binder_name) <+> ptext SLIT("statements must end in expression:"),
nest 4 (ppr e)]
-
-thErr what
- = ptext SLIT("Template Haskell") <+> text what <+>
- ptext SLIT("illegal in a stage-1 compiler")
-
-
-withWarning
- = sep [quotes (ptext SLIT("with")),
- ptext SLIT("is deprecated, use"),
- quotes (ptext SLIT("let")),
- ptext SLIT("instead")]
+ where
+ binder_name = case do_or_lc of
+ MDoExpr -> "mdo"
+ other -> "do"
+
+#ifdef GHCI
+checkTH e what = returnM () -- OK
+#else
+checkTH e what -- Raise an error in a stage-1 compiler
+ = addErr (vcat [ptext SLIT("Template Haskell") <+> text what <+>
+ ptext SLIT("illegal in a stage-1 compiler"),
+ nest 2 (ppr e)])
+#endif
+
+parStmtErr = addErr (ptext SLIT("Illegal parallel list comprehension: use -fglagow-exts"))
+
+badIpBinds binds
+ = hang (ptext SLIT("Implicit-parameter bindings illegal in a parallel list comprehension:")) 4
+ (ppr binds)
\end{code}