%
% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
%
\section[RnExpr]{Renaming of expressions}
Basically dependency analysis.
Handles @Match@, @GRHSs@, @HsExpr@, and @Qualifier@ datatypes. In
general, all of these functions return a renamed thing, and a set of
free variables.
\begin{code}
module RnExpr (
rnLExpr, rnExpr, rnStmts
) where
#include "HsVersions.h"
#ifdef GHCI
import TcSplice( runQuasiQuoteExpr )
#endif /* GHCI */
import RnSource ( rnSrcDecls, findSplice )
import RnBinds ( rnLocalBindsAndThen, rnLocalValBindsLHS, rnLocalValBindsRHS,
rnMatchGroup, makeMiniFixityEnv)
import HsSyn
import TcRnMonad
import TcEnv ( thRnBrack )
import RnEnv
import RnTypes ( rnHsTypeFVs, rnSplice, checkTH,
mkOpFormRn, mkOpAppRn, mkNegAppRn, checkSectionPrec)
import RnPat
import DynFlags
import BasicTypes ( FixityDirection(..) )
import PrelNames
import Name
import NameSet
import RdrName
import LoadIface ( loadInterfaceForName )
import UniqSet
import Data.List
import Util ( isSingleton )
import ListSetOps ( removeDups )
import Outputable
import SrcLoc
import FastString
import Control.Monad
\end{code}
\begin{code}
thenM :: Monad a => a b -> (b -> a c) -> a c
thenM = (>>=)
thenM_ :: Monad a => a b -> a c -> a c
thenM_ = (>>)
\end{code}
%************************************************************************
%* *
\subsubsection{Expressions}
%* *
%************************************************************************
\begin{code}
rnExprs :: [LHsExpr RdrName] -> RnM ([LHsExpr Name], FreeVars)
rnExprs ls = rnExprs' ls emptyUniqSet
where
rnExprs' [] acc = return ([], acc)
rnExprs' (expr:exprs) acc
= rnLExpr expr `thenM` \ (expr', fvExpr) ->
let
acc' = acc `plusFV` fvExpr
in
acc' `seq` rnExprs' exprs acc' `thenM` \ (exprs', fvExprs) ->
return (expr':exprs', fvExprs)
\end{code}
Variables. We look up the variable and return the resulting name.
\begin{code}
rnLExpr :: LHsExpr RdrName -> RnM (LHsExpr Name, FreeVars)
rnLExpr = wrapLocFstM rnExpr
rnExpr :: HsExpr RdrName -> RnM (HsExpr Name, FreeVars)
finishHsVar :: Name -> RnM (HsExpr Name, FreeVars)
finishHsVar name
= do { ignore_asserts <- doptM Opt_IgnoreAsserts
; if ignore_asserts || not (name `hasKey` assertIdKey)
then return (HsVar name, unitFV name)
else do { e <- mkAssertErrorExpr
; return (e, unitFV name) } }
rnExpr (HsVar v)
= do name <- lookupOccRn v
finishHsVar name
rnExpr (HsIPVar v)
= newIPNameRn v `thenM` \ name ->
return (HsIPVar name, emptyFVs)
rnExpr (HsLit lit@(HsString s))
= do {
opt_OverloadedStrings <- xoptM Opt_OverloadedStrings
; if opt_OverloadedStrings then
rnExpr (HsOverLit (mkHsIsString s placeHolderType))
else
rnLit lit `thenM_`
return (HsLit lit, emptyFVs)
}
rnExpr (HsLit lit)
= rnLit lit `thenM_`
return (HsLit lit, emptyFVs)
rnExpr (HsOverLit lit)
= rnOverLit lit `thenM` \ (lit', fvs) ->
return (HsOverLit lit', fvs)
rnExpr (HsApp fun arg)
= rnLExpr fun `thenM` \ (fun',fvFun) ->
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
; (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 ->
return (final_e, fv_e `plusFV` fv_neg)
rnExpr e@(HsBracket br_body)
= checkTH e "bracket" `thenM_`
rnBracket br_body `thenM` \ (body', fvs_e) ->
return (HsBracket body', fvs_e)
rnExpr (HsSpliceE splice)
= rnSplice splice `thenM` \ (splice', fvs) ->
return (HsSpliceE splice', fvs)
#ifndef GHCI
rnExpr e@(HsQuasiQuoteE _) = pprPanic "Cant do quasiquotation without GHCi" (ppr e)
#else
rnExpr (HsQuasiQuoteE qq)
= runQuasiQuoteExpr qq `thenM` \ (L _ expr') ->
rnExpr expr'
#endif /* GHCI */
rnExpr (HsPar (L loc (section@(SectionL {}))))
= do { (section', fvs) <- rnSection section
; return (HsPar (L loc section'), fvs) }
rnExpr (HsPar (L loc (section@(SectionR {}))))
= do { (section', fvs) <- rnSection section
; return (HsPar (L loc section'), fvs) }
rnExpr (HsPar e)
= do { (e', fvs_e) <- rnLExpr e
; return (HsPar e', fvs_e) }
rnExpr expr@(SectionL {})
= do { addErr (sectionErr expr); rnSection expr }
rnExpr expr@(SectionR {})
= do { addErr (sectionErr expr); rnSection expr }
rnExpr (HsCoreAnn ann expr)
= rnLExpr expr `thenM` \ (expr', fvs_expr) ->
return (HsCoreAnn ann expr', fvs_expr)
rnExpr (HsSCC lbl expr)
= rnLExpr expr `thenM` \ (expr', fvs_expr) ->
return (HsSCC lbl expr', fvs_expr)
rnExpr (HsTickPragma info expr)
= rnLExpr expr `thenM` \ (expr', fvs_expr) ->
return (HsTickPragma info expr', fvs_expr)
rnExpr (HsLam matches)
= rnMatchGroup LambdaExpr matches `thenM` \ (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) ->
return (HsCase new_expr new_matches, e_fvs `plusFV` ms_fvs)
rnExpr (HsLet binds expr)
= rnLocalBindsAndThen binds $ \ binds' ->
rnLExpr expr `thenM` \ (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 (ExplicitList _ exps)
= rnExprs exps `thenM` \ (exps', fvs) ->
return (ExplicitList placeHolderType exps', fvs)
rnExpr (ExplicitPArr _ exps)
= rnExprs exps `thenM` \ (exps', fvs) ->
return (ExplicitPArr placeHolderType exps', 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) <- 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) <- rnHsRecBinds HsRecFieldUpd rbinds
; return (RecordUpd expr' rbinds' [] [] [],
fvExpr `plusFV` fvRbinds) }
rnExpr (ExprWithTySig expr pty)
= do { (pty', fvTy) <- rnHsTypeFVs doc pty
; (expr', fvExpr) <- bindSigTyVarsFV (hsExplicitTvs pty') $
rnLExpr expr
; return (ExprWithTySig expr' pty', fvExpr `plusFV` fvTy) }
where
doc = text "In an expression type signature"
rnExpr (HsIf _ p b1 b2)
= do { (p', fvP) <- rnLExpr p
; (b1', fvB1) <- rnLExpr b1
; (b2', fvB2) <- rnLExpr b2
; rebind <- xoptM Opt_RebindableSyntax
; if not rebind
then return (HsIf Nothing p' b1' b2', plusFVs [fvP, fvB1, fvB2])
else do { c <- liftM HsVar (lookupOccRn (mkVarUnqual (fsLit "ifThenElse")))
; return (HsIf (Just c) p' b1' b2', plusFVs [fvP, fvB1, fvB2]) }}
rnExpr (HsType a)
= rnHsTypeFVs doc a `thenM` \ (t, fvT) ->
return (HsType t, fvT)
where
doc = text "In a type argument"
rnExpr (ArithSeq _ seq)
= rnArithSeq seq `thenM` \ (new_seq, fvs) ->
return (ArithSeq noPostTcExpr new_seq, fvs)
rnExpr (PArrSeq _ seq)
= rnArithSeq seq `thenM` \ (new_seq, fvs) ->
return (PArrSeq noPostTcExpr new_seq, fvs)
\end{code}
These three are pattern syntax appearing in expressions.
Since all the symbols are reservedops we can simply reject them.
We return a (bogus) EWildPat in each case.
\begin{code}
rnExpr e@EWildPat = patSynErr e
rnExpr e@(EAsPat {}) = patSynErr e
rnExpr e@(EViewPat {}) = patSynErr e
rnExpr e@(ELazyPat {}) = patSynErr e
\end{code}
%************************************************************************
%* *
Arrow notation
%* *
%************************************************************************
\begin{code}
rnExpr (HsProc pat body)
= newArrowScope $
rnPat ProcExpr pat $ \ pat' ->
rnCmdTop body `thenM` \ (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) ->
return (HsArrApp arrow' arg' placeHolderType ho rtl,
fvArrow `plusFV` fvArg)
where
select_arrow_scope tc = case ho of
HsHigherOrderApp -> tc
HsFirstOrderApp -> escapeArrowScope tc
rnExpr (HsArrForm op (Just _) [arg1, arg2])
= escapeArrowScope (rnLExpr 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 ->
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) ->
return (HsArrForm op' fixity cmds', fvOp `plusFV` fvCmds)
rnExpr other = pprPanic "rnExpr: unexpected expression" (ppr other)
rnSection :: HsExpr RdrName -> RnM (HsExpr Name, FreeVars)
rnSection section@(SectionR op expr)
= do { (op', fvs_op) <- rnLExpr op
; (expr', fvs_expr) <- rnLExpr expr
; checkSectionPrec InfixR section op' expr'
; return (SectionR op' expr', fvs_op `plusFV` fvs_expr) }
rnSection section@(SectionL expr op)
= do { (expr', fvs_expr) <- rnLExpr expr
; (op', fvs_op) <- rnLExpr op
; checkSectionPrec InfixL section op' expr'
; return (SectionL expr' op', fvs_op `plusFV` fvs_expr) }
rnSection other = pprPanic "rnSection" (ppr other)
\end{code}
%************************************************************************
%* *
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 [] = return ([], emptyFVs)
rnCmdArgs (arg:args)
= rnCmdTop arg `thenM` \ (arg',fvArg) ->
rnCmdArgs args `thenM` \ (args',fvArgs) ->
return (arg':args', fvArg `plusFV` fvArgs)
rnCmdTop :: LHsCmdTop RdrName -> RnM (LHsCmdTop Name, FreeVars)
rnCmdTop = wrapLocFstM rnCmdTop'
where
rnCmdTop' (HsCmdTop cmd _ _ _)
= rnLExpr (convertOpFormsLCmd cmd) `thenM` \ (cmd', fvCmd) ->
let
cmd_names = [arrAName, composeAName, firstAName] ++
nameSetToList (methodNamesCmd (unLoc cmd'))
in
lookupSyntaxTable cmd_names `thenM` \ (cmd_names', cmd_fvs) ->
return (HsCmdTop cmd' [] placeHolderType cmd_names',
fvCmd `plusFV` cmd_fvs)
convertOpFormsLCmd :: LHsCmd id -> LHsCmd id
convertOpFormsLCmd = fmap convertOpFormsCmd
convertOpFormsCmd :: HsCmd id -> HsCmd id
convertOpFormsCmd (HsApp c e) = HsApp (convertOpFormsLCmd c) e
convertOpFormsCmd (HsLam match) = HsLam (convertOpFormsMatch match)
convertOpFormsCmd (OpApp c1 op fixity c2)
= let
arg1 = L (getLoc c1) $ HsCmdTop (convertOpFormsLCmd c1) [] placeHolderType []
arg2 = L (getLoc c2) $ HsCmdTop (convertOpFormsLCmd c2) [] placeHolderType []
in
HsArrForm op (Just fixity) [arg1, arg2]
convertOpFormsCmd (HsPar c) = HsPar (convertOpFormsLCmd c)
convertOpFormsCmd (HsCase exp matches)
= HsCase exp (convertOpFormsMatch matches)
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 c = c
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 stmt@(RecStmt { recS_stmts = stmts })
= stmt { recS_stmts = map (fmap convertOpFormsStmt) stmts }
convertOpFormsStmt stmt = stmt
convertOpFormsMatch :: MatchGroup id -> MatchGroup id
convertOpFormsMatch (MatchGroup ms ty)
= MatchGroup (map (fmap convert) ms) ty
where convert (Match pat mty grhss)
= Match pat mty (convertOpFormsGRHSs grhss)
convertOpFormsGRHSs :: GRHSs id -> GRHSs id
convertOpFormsGRHSs (GRHSs grhss binds)
= GRHSs (map convertOpFormsGRHS grhss) binds
convertOpFormsGRHS :: Located (GRHS id) -> Located (GRHS id)
convertOpFormsGRHS = fmap convert
where
convert (GRHS stmts cmd) = GRHS stmts (convertOpFormsLCmd cmd)
type CmdNeeds = FreeVars
methodNamesLCmd :: LHsCmd Name -> CmdNeeds
methodNamesLCmd = methodNamesCmd . unLoc
methodNamesCmd :: HsCmd Name -> CmdNeeds
methodNamesCmd (HsArrApp _arrow _arg _ HsFirstOrderApp _rtl)
= emptyFVs
methodNamesCmd (HsArrApp _arrow _arg _ HsHigherOrderApp _rtl)
= unitFV appAName
methodNamesCmd (HsArrForm {}) = emptyFVs
methodNamesCmd (HsPar c) = methodNamesLCmd c
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 (HsCase _ matches)
= methodNamesMatch matches `addOneFV` choiceAName
methodNamesCmd _ = emptyFVs
methodNamesMatch :: MatchGroup Name -> FreeVars
methodNamesMatch (MatchGroup ms _)
= plusFVs (map do_one ms)
where
do_one (L _ (Match _ _ grhss)) = methodNamesGRHSs grhss
methodNamesGRHSs :: GRHSs Name -> FreeVars
methodNamesGRHSs (GRHSs grhss _) = plusFVs (map methodNamesGRHS grhss)
methodNamesGRHS :: Located (GRHS Name) -> CmdNeeds
methodNamesGRHS (L _ (GRHS _ rhs)) = methodNamesLCmd rhs
methodNamesStmts :: [Located (StmtLR Name Name)] -> FreeVars
methodNamesStmts stmts = plusFVs (map methodNamesLStmt stmts)
methodNamesLStmt :: Located (StmtLR Name Name) -> FreeVars
methodNamesLStmt = methodNamesStmt . unLoc
methodNamesStmt :: StmtLR Name Name -> FreeVars
methodNamesStmt (ExprStmt cmd _ _) = methodNamesLCmd cmd
methodNamesStmt (BindStmt _ cmd _ _) = methodNamesLCmd cmd
methodNamesStmt (RecStmt { recS_stmts = stmts }) = methodNamesStmts stmts `addOneFV` loopAName
methodNamesStmt (LetStmt _) = emptyFVs
methodNamesStmt (ParStmt _) = emptyFVs
methodNamesStmt (TransformStmt {}) = emptyFVs
methodNamesStmt (GroupStmt {}) = emptyFVs
\end{code}
%************************************************************************
%* *
Arithmetic sequences
%* *
%************************************************************************
\begin{code}
rnArithSeq :: ArithSeqInfo RdrName -> RnM (ArithSeqInfo Name, FreeVars)
rnArithSeq (From expr)
= rnLExpr expr `thenM` \ (expr', fvExpr) ->
return (From expr', fvExpr)
rnArithSeq (FromThen expr1 expr2)
= rnLExpr expr1 `thenM` \ (expr1', fvExpr1) ->
rnLExpr expr2 `thenM` \ (expr2', fvExpr2) ->
return (FromThen expr1' expr2', fvExpr1 `plusFV` fvExpr2)
rnArithSeq (FromTo expr1 expr2)
= rnLExpr expr1 `thenM` \ (expr1', fvExpr1) ->
rnLExpr expr2 `thenM` \ (expr2', 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) ->
return (FromThenTo expr1' expr2' expr3',
plusFVs [fvExpr1, fvExpr2, fvExpr3])
\end{code}
%************************************************************************
%* *
Template Haskell brackets
%* *
%************************************************************************
\begin{code}
rnBracket :: HsBracket RdrName -> RnM (HsBracket Name, FreeVars)
rnBracket (VarBr n) = do { name <- lookupOccRn n
; this_mod <- getModule
; unless (nameIsLocalOrFrom this_mod name) $
do { _ <- loadInterfaceForName msg name
; return () }
; 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 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 (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"))
; gbl_env <- getGblEnv
; let new_gbl_env = gbl_env { tcg_dus = emptyDUs }
; (tcg_env, group') <- setGblEnv new_gbl_env $
setStage thRnBrack $
rnSrcDecls group
; 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}
%************************************************************************
%* *
\subsubsection{@Stmt@s: in @do@ expressions}
%* *
%************************************************************************
\begin{code}
rnStmts :: HsStmtContext Name -> [LStmt RdrName]
-> RnM (thing, FreeVars)
-> RnM (([LStmt Name], thing), FreeVars)
rnStmts (MDoExpr _) stmts thing_inside = rnMDoStmts stmts thing_inside
rnStmts ctxt stmts thing_inside = rnNormalStmts ctxt stmts (\ _ -> thing_inside)
rnNormalStmts :: HsStmtContext Name -> [LStmt RdrName]
-> ([Name] -> RnM (thing, FreeVars))
-> RnM (([LStmt Name], thing), FreeVars)
rnNormalStmts _ [] thing_inside
= do { (res, fvs) <- thing_inside []
; return (([], res), fvs) }
rnNormalStmts ctxt (stmt@(L loc _) : stmts) thing_inside
= do { ((stmts1, (stmts2, thing)), fvs)
<- setSrcSpan loc $
rnStmt ctxt stmt $ \ bndrs1 ->
rnNormalStmts ctxt stmts $ \ bndrs2 ->
thing_inside (bndrs1 ++ bndrs2)
; return (((stmts1 ++ stmts2), thing), fvs) }
rnStmt :: HsStmtContext Name -> LStmt RdrName
-> ([Name] -> RnM (thing, FreeVars))
-> RnM (([LStmt Name], thing), FreeVars)
rnStmt _ (L loc (ExprStmt expr _ _)) thing_inside
= do { (expr', fv_expr) <- rnLExpr expr
; (then_op, fvs1) <- lookupSyntaxName thenMName
; (thing, fvs2) <- thing_inside []
; return (([L loc (ExprStmt expr' then_op placeHolderType)], thing),
fv_expr `plusFV` fvs1 `plusFV` fvs2) }
rnStmt ctxt (L loc (BindStmt pat expr _ _)) thing_inside
= do { (expr', fv_expr) <- rnLExpr expr
; (bind_op, fvs1) <- lookupSyntaxName bindMName
; (fail_op, fvs2) <- lookupSyntaxName failMName
; 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) }}
rnStmt ctxt (L loc (LetStmt binds)) thing_inside
= do { checkLetStmt ctxt binds
; rnLocalBindsAndThen binds $ \binds' -> do
{ (thing, fvs) <- thing_inside (collectLocalBinders binds')
; return (([L loc (LetStmt binds')], thing), fvs) } }
rnStmt ctxt (L _ (RecStmt { recS_stmts = rec_stmts })) thing_inside
= do { checkRecStmt ctxt
; rn_rec_stmts_and_then 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
segs_w_fwd_refs = addFwdRefs segs
grouped_segs = glomSegments segs_w_fwd_refs
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 (([L loc (ParStmt segs')], thing), fvs) }
rnStmt ctxt (L loc (TransformStmt stmts _ using by)) thing_inside
= do { checkTransformStmt ctxt
; (using', fvs1) <- rnLExpr using
; ((stmts', (by', used_bndrs, thing)), fvs2)
<- rnNormalStmts (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
; return ((by', used_bndrs, thing), fvs) }
; return (([L loc (TransformStmt stmts' used_bndrs using' by')], thing),
fvs1 `plusFV` fvs2) }
rnStmt ctxt (L loc (GroupStmt stmts _ by using)) thing_inside
= do { checkTransformStmt ctxt
; (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) }
; ((stmts', (by', used_bndrs, thing)), fvs2)
<- rnNormalStmts (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
; 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])
rnParallelStmts :: forall thing. HsStmtContext Name
-> [ParSeg RdrName]
-> ([Name] -> RnM (thing, FreeVars))
-> RnM (([ParSeg Name], thing), FreeVars)
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)
<- rnNormalStmts 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.
%************************************************************************
%* *
\subsubsection{mdo expressions}
%* *
%************************************************************************
\begin{code}
type FwdRefs = NameSet
type Segment stmts = (Defs,
Uses,
FwdRefs,
stmts)
rnMDoStmts :: [LStmt RdrName]
-> RnM (thing, FreeVars)
-> RnM (([LStmt Name], thing), FreeVars)
rnMDoStmts stmts thing_inside
= rn_rec_stmts_and_then stmts $ \ segs -> do
{ (thing, fvs_later) <- thing_inside
; let segs_w_fwd_refs = addFwdRefs segs
grouped_segs = glomSegments segs_w_fwd_refs
(stmts', fvs) = segsToStmts emptyRecStmt grouped_segs fvs_later
; return ((stmts', thing), fvs) }
rn_rec_stmts_and_then :: [LStmt RdrName]
-> ([Segment (LStmt Name)] -> RnM (a, FreeVars))
-> RnM (a, FreeVars)
rn_rec_stmts_and_then s cont
= do {
fix_env <- makeMiniFixityEnv (collectRecStmtsFixities s)
; new_lhs_and_fv <- rn_rec_stmts_lhs fix_env s
; let bound_names = collectLStmtsBinders (map fst new_lhs_and_fv)
; bindLocalNamesFV bound_names $
addLocalFixities fix_env bound_names $ do
{ segs <- rn_rec_stmts bound_names new_lhs_and_fv
; (res, fvs) <- cont segs
; warnUnusedLocalBinds bound_names fvs
; return (res, fvs) }}
collectRecStmtsFixities :: [LStmtLR RdrName RdrName] -> [LFixitySig RdrName]
collectRecStmtsFixities l =
foldr (\ s -> \acc -> case s of
(L _ (LetStmt (HsValBinds (ValBindsIn _ sigs)))) ->
foldr (\ sig -> \ acc -> case sig of
(L loc (FixSig s)) -> (L loc s) : acc
_ -> acc) acc sigs
_ -> acc) [] l
rn_rec_stmt_lhs :: MiniFixityEnv
-> LStmt RdrName
-> RnM [(LStmtLR Name RdrName, FreeVars)]
rn_rec_stmt_lhs _ (L loc (ExprStmt expr a b)) = return [(L loc (ExprStmt expr a b),
emptyFVs)]
rn_rec_stmt_lhs fix_env (L loc (BindStmt pat expr a b))
= do
(pat', fv_pat) <- rnBindPat (localRecNameMaker fix_env) pat
return [(L loc (BindStmt pat' expr a b),
fv_pat)]
rn_rec_stmt_lhs _ (L _ (LetStmt binds@(HsIPBinds _)))
= failWith (badIpBinds (ptext (sLit "an mdo expression")) binds)
rn_rec_stmt_lhs fix_env (L loc (LetStmt (HsValBinds binds)))
= do (_bound_names, binds') <- rnLocalValBindsLHS fix_env binds
return [(L loc (LetStmt (HsValBinds binds')),
emptyFVs
)]
rn_rec_stmt_lhs fix_env (L _ (RecStmt { recS_stmts = stmts }))
= rn_rec_stmts_lhs fix_env stmts
rn_rec_stmt_lhs _ stmt@(L _ (ParStmt _))
= pprPanic "rn_rec_stmt" (ppr stmt)
rn_rec_stmt_lhs _ stmt@(L _ (TransformStmt {}))
= pprPanic "rn_rec_stmt" (ppr stmt)
rn_rec_stmt_lhs _ stmt@(L _ (GroupStmt {}))
= pprPanic "rn_rec_stmt" (ppr stmt)
rn_rec_stmt_lhs _ (L _ (LetStmt EmptyLocalBinds))
= panic "rn_rec_stmt LetStmt EmptyLocalBinds"
rn_rec_stmts_lhs :: MiniFixityEnv
-> [LStmt RdrName]
-> RnM [(LStmtLR Name RdrName, FreeVars)]
rn_rec_stmts_lhs fix_env stmts
= do { ls <- concatMapM (rn_rec_stmt_lhs fix_env) stmts
; let boundNames = collectLStmtsBinders (map fst ls)
; checkDupNames boundNames
; return ls }
rn_rec_stmt :: [Name] -> LStmtLR Name RdrName -> FreeVars -> RnM [Segment (LStmt Name)]
rn_rec_stmt _ (L loc (ExprStmt expr _ _)) _
= rnLExpr expr `thenM` \ (expr', fvs) ->
lookupSyntaxName thenMName `thenM` \ (then_op, fvs1) ->
return [(emptyNameSet, fvs `plusFV` fvs1, emptyNameSet,
L loc (ExprStmt expr' then_op placeHolderType))]
rn_rec_stmt _ (L loc (BindStmt pat' expr _ _)) fv_pat
= rnLExpr expr `thenM` \ (expr', fv_expr) ->
lookupSyntaxName bindMName `thenM` \ (bind_op, fvs1) ->
lookupSyntaxName failMName `thenM` \ (fail_op, fvs2) ->
let
bndrs = mkNameSet (collectPatBinders pat')
fvs = fv_expr `plusFV` fv_pat `plusFV` fvs1 `plusFV` fvs2
in
return [(bndrs, fvs, bndrs `intersectNameSet` fvs,
L loc (BindStmt pat' expr' bind_op fail_op))]
rn_rec_stmt _ (L _ (LetStmt binds@(HsIPBinds _))) _
= failWith (badIpBinds (ptext (sLit "an mdo expression")) binds)
rn_rec_stmt all_bndrs (L loc (LetStmt (HsValBinds binds'))) _ = do
(binds', du_binds) <-
rnLocalValBindsRHS (mkNameSet all_bndrs) binds'
return [(duDefs du_binds, allUses du_binds,
emptyNameSet, L loc (LetStmt (HsValBinds binds')))]
rn_rec_stmt _ stmt@(L _ (RecStmt {})) _
= pprPanic "rn_rec_stmt: RecStmt" (ppr stmt)
rn_rec_stmt _ stmt@(L _ (ParStmt {})) _
= pprPanic "rn_rec_stmt: ParStmt" (ppr stmt)
rn_rec_stmt _ stmt@(L _ (TransformStmt {})) _
= pprPanic "rn_rec_stmt: TransformStmt" (ppr stmt)
rn_rec_stmt _ stmt@(L _ (GroupStmt {})) _
= 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 = mapM (uncurry (rn_rec_stmt bndrs)) stmts `thenM` \ segs_s ->
return (concat segs_s)
addFwdRefs :: [Segment a] -> [Segment a]
addFwdRefs pairs
= fst (foldr mk_seg ([], emptyNameSet) pairs)
where
mk_seg (defs, uses, fwds, stmts) (segs, later_defs)
= (new_seg : segs, all_defs)
where
new_seg = (defs, uses, new_fwds, stmts)
all_defs = later_defs `unionNameSets` defs
new_fwds = fwds `unionNameSets` (uses `intersectNameSet` later_defs)
glomSegments :: [Segment (LStmt Name)] -> [Segment [LStmt Name]]
glomSegments [] = []
glomSegments ((defs,uses,fwds,stmt) : segs)
= (seg_defs, seg_uses, seg_fwds, seg_stmts) : others
where
segs' = glomSegments segs
(extras, others) = grab uses segs'
(ds, us, fs, ss) = unzip4 extras
seg_defs = plusFVs ds `plusFV` defs
seg_uses = plusFVs us `plusFV` uses
seg_fwds = plusFVs fs `plusFV` fwds
seg_stmts = stmt : concat ss
grab :: NameSet
-> [Segment a]
-> ([Segment a],
[Segment a])
grab uses dus
= (reverse yeses, reverse noes)
where
(noes, yeses) = span not_needed (reverse dus)
not_needed (defs,_,_,_) = not (intersectsNameSet defs uses)
segsToStmts :: Stmt Name
-> [Segment [LStmt Name]]
-> FreeVars
-> ([LStmt Name], FreeVars)
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 empty_rec_stmt segs fvs_later
new_stmt | non_rec = head ss
| 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
\end{code}
%************************************************************************
%* *
\subsubsection{Assertion utils}
%* *
%************************************************************************
\begin{code}
srcSpanPrimLit :: SrcSpan -> HsExpr Name
srcSpanPrimLit span = HsLit (HsStringPrim (mkFastString (showSDocOneLine (ppr span))))
mkAssertErrorExpr :: RnM (HsExpr Name)
mkAssertErrorExpr
= getSrcSpanM `thenM` \ sloc ->
return (HsApp (L sloc (HsVar assertErrorName))
(L sloc (srcSpanPrimLit sloc)))
\end{code}
Note [Adding the implicit parameter to 'assert']
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The renamer transforms (assert e1 e2) to (assert "Foo.hs:27" e1 e2).
By doing this in the renamer we allow the typechecker to just see the
expanded application and do the right thing. But it's not really
the Right Thing because there's no way to "undo" if you want to see
the original source code. We'll have fix this in due course, when
we care more about being able to reconstruct the exact original
program.
%************************************************************************
%* *
\subsubsection{Errors}
%* *
%************************************************************************
\begin{code}
checkLetStmt :: HsStmtContext Name -> HsLocalBinds RdrName -> RnM ()
checkLetStmt (ParStmtCtxt _) (HsIPBinds binds) = addErr (badIpBinds (ptext (sLit "a parallel list comprehension:")) binds)
checkLetStmt _ctxt _binds = return ()
checkRecStmt :: HsStmtContext Name -> RnM ()
checkRecStmt (MDoExpr {}) = return ()
checkRecStmt (DoExpr {}) = return ()
checkRecStmt ctxt = addErr msg
where
msg = ptext (sLit "Illegal 'rec' stmt in") <+> pprStmtContext ctxt
checkParStmt :: HsStmtContext Name -> RnM ()
checkParStmt _
= 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
= do { transform_list_comp <- xoptM Opt_TransformListComp
; checkErr transform_list_comp msg }
where
msg = ptext (sLit "Illegal transform or grouping list comprehension: use -XTransformListComp")
checkTransformStmt (ParStmtCtxt ctxt) = checkTransformStmt ctxt
checkTransformStmt (TransformStmtCtxt ctxt) = checkTransformStmt ctxt
checkTransformStmt ctxt = addErr msg
where
msg = ptext (sLit "Illegal transform or grouping in") <+> pprStmtContext ctxt
checkTupleSection :: [HsTupArg RdrName] -> RnM ()
checkTupleSection args
= do { tuple_section <- xoptM Opt_TupleSections
; checkErr (all tupArgPresent args || tuple_section) msg }
where
msg = ptext (sLit "Illegal tuple section: use -XTupleSections")
sectionErr :: HsExpr RdrName -> SDoc
sectionErr expr
= hang (ptext (sLit "A section must be enclosed in parentheses"))
2 (ptext (sLit "thus:") <+> (parens (ppr expr)))
patSynErr :: HsExpr RdrName -> RnM (HsExpr Name, FreeVars)
patSynErr e = do { addErr (sep [ptext (sLit "Pattern syntax in expression context:"),
nest 4 (ppr e)])
; return (EWildPat, emptyFVs) }
badIpBinds :: Outputable a => SDoc -> a -> SDoc
badIpBinds what binds
= hang (ptext (sLit "Implicit-parameter bindings illegal in") <+> what)
2 (ppr binds)
\end{code}