+++ /dev/null
-%
-% (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"
-
-import RnSource ( rnSrcDecls, rnSplice, checkTH )
-import RnBinds ( rnLocalBindsAndThen, rnValBinds,
- rnMatchGroup, trimWith )
-import HsSyn
-import RnHsSyn
-import TcRnMonad
-import RnEnv
-import OccName ( plusOccEnv )
-import RnNames ( getLocalDeclBinders, extendRdrEnvRn )
-import RnTypes ( rnHsTypeFVs, rnLPat, rnOverLit, rnPatsAndThen, rnLit,
- mkOpFormRn, mkOpAppRn, mkNegAppRn, checkSectionPrec,
- dupFieldErr, checkTupSize )
-import DynFlags ( DynFlag(..) )
-import BasicTypes ( FixityDirection(..) )
-import PrelNames ( thFAKE, hasKey, assertIdKey, assertErrorName,
- loopAName, choiceAName, appAName, arrAName, composeAName, firstAName,
- negateName, thenMName, bindMName, failMName )
-#if defined(GHCI) && defined(BREAKPOINT)
-import PrelNames ( breakpointJumpName, undefined_RDR, breakpointIdKey )
-import UniqFM ( eltsUFM )
-import DynFlags ( GhcMode(..) )
-import SrcLoc ( srcSpanFile, srcSpanStartLine )
-import Name ( isTyVarName )
-#endif
-import Name ( Name, nameOccName, nameIsLocalOrFrom )
-import NameSet
-import RdrName ( RdrName, emptyGlobalRdrEnv, extendLocalRdrEnv, lookupLocalRdrEnv )
-import LoadIface ( loadHomeInterface )
-import UniqFM ( isNullUFM )
-import UniqSet ( emptyUniqSet )
-import List ( nub )
-import Util ( isSingleton )
-import ListSetOps ( removeDups )
-import Maybes ( expectJust )
-import Outputable
-import SrcLoc ( Located(..), unLoc, getLoc, cmpLocated )
-import FastString
-
-import List ( unzip4 )
-\end{code}
-
-
-%************************************************************************
-%* *
-\subsubsection{Expressions}
-%* *
-%************************************************************************
-
-\begin{code}
-rnExprs :: [LHsExpr RdrName] -> RnM ([LHsExpr Name], FreeVars)
-rnExprs ls = rnExprs' ls emptyUniqSet
- where
- rnExprs' [] acc = returnM ([], acc)
- rnExprs' (expr:exprs) acc
- = rnLExpr expr `thenM` \ (expr', fvExpr) ->
-
- -- Now we do a "seq" on the free vars because typically it's small
- -- or empty, especially in very long lists of constants
- let
- acc' = acc `plusFV` fvExpr
- in
- (grubby_seqNameSet acc' rnExprs') exprs acc' `thenM` \ (exprs', fvExprs) ->
- returnM (expr':exprs', fvExprs)
-
--- Grubby little function to do "seq" on namesets; replace by proper seq when GHC can do seq
-grubby_seqNameSet ns result | isNullUFM ns = result
- | otherwise = result
-\end{code}
-
-Variables. We look up the variable and return the resulting name.
-
-\begin{code}
-rnLExpr :: LHsExpr RdrName -> RnM (LHsExpr Name, FreeVars)
-rnLExpr = wrapLocFstM rnExpr
-
-rnExpr :: HsExpr RdrName -> RnM (HsExpr Name, FreeVars)
-
-rnExpr (HsVar v)
- = do name <- lookupOccRn v
- localRdrEnv <- getLocalRdrEnv
- lclEnv <- getLclEnv
- ignore_asserts <- doptM Opt_IgnoreAsserts
- ignore_breakpoints <- doptM Opt_IgnoreBreakpoints
- let conds = [ (name `hasKey` assertIdKey
- && not ignore_asserts,
- do (e, fvs) <- mkAssertErrorExpr
- return (e, fvs `addOneFV` name))
-#if defined(GHCI) && defined(BREAKPOINT)
- , (name `hasKey` breakpointIdKey
- && not ignore_breakpoints,
- do ghcMode <- getGhcMode
- case ghcMode of
- Interactive
- -> do let isWantedName = not.isTyVarName
- (e, fvs) <- mkBreakPointExpr (filter isWantedName (eltsUFM localRdrEnv))
- return (e, fvs `addOneFV` name)
- _ -> return (HsVar name, unitFV name)
- )
-#endif
- ]
- case lookup True conds of
- Just action -> action
- Nothing -> return (HsVar name, unitFV name)
-
-rnExpr (HsIPVar v)
- = newIPNameRn v `thenM` \ name ->
- returnM (HsIPVar name, emptyFVs)
-
-rnExpr (HsLit lit)
- = rnLit lit `thenM_`
- returnM (HsLit lit, emptyFVs)
-
-rnExpr (HsOverLit lit)
- = rnOverLit lit `thenM` \ (lit', fvs) ->
- returnM (HsOverLit lit', fvs)
-
-rnExpr (HsApp fun arg)
- = rnLExpr fun `thenM` \ (fun',fvFun) ->
- rnLExpr arg `thenM` \ (arg',fvArg) ->
- returnM (HsApp fun' arg', fvFun `plusFV` fvArg)
-
-rnExpr (OpApp e1 op _ e2)
- = rnLExpr e1 `thenM` \ (e1', fv_e1) ->
- rnLExpr e2 `thenM` \ (e2', fv_e2) ->
- rnLExpr op `thenM` \ (op'@(L _ (HsVar op_name)), fv_op) ->
-
- -- Deal with fixity
- -- When renaming code synthesised from "deriving" declarations
- -- we used to avoid fixity stuff, but we can't easily tell any
- -- more, so I've removed the test. Adding HsPars in TcGenDeriv
- -- should prevent bad things happening.
- lookupFixityRn op_name `thenM` \ fixity ->
- mkOpAppRn e1' op' fixity e2' `thenM` \ final_e ->
-
- returnM (final_e,
- fv_e1 `plusFV` fv_op `plusFV` fv_e2)
-
-rnExpr (NegApp e _)
- = rnLExpr e `thenM` \ (e', fv_e) ->
- lookupSyntaxName negateName `thenM` \ (neg_name, fv_neg) ->
- mkNegAppRn e' neg_name `thenM` \ final_e ->
- returnM (final_e, fv_e `plusFV` fv_neg)
-
-rnExpr (HsPar e)
- = rnLExpr e `thenM` \ (e', fvs_e) ->
- returnM (HsPar e', fvs_e)
-
--- Template Haskell extensions
--- Don't ifdef-GHCI them because we want to fail gracefully
--- (not with an rnExpr crash) in a stage-1 compiler.
-rnExpr e@(HsBracket br_body)
- = checkTH e "bracket" `thenM_`
- rnBracket br_body `thenM` \ (body', fvs_e) ->
- returnM (HsBracket body', fvs_e)
-
-rnExpr e@(HsSpliceE splice)
- = rnSplice splice `thenM` \ (splice', fvs) ->
- returnM (HsSpliceE splice', fvs)
-
-rnExpr section@(SectionL expr op)
- = rnLExpr expr `thenM` \ (expr', fvs_expr) ->
- rnLExpr op `thenM` \ (op', fvs_op) ->
- checkSectionPrec InfixL section op' expr' `thenM_`
- returnM (SectionL expr' op', fvs_op `plusFV` fvs_expr)
-
-rnExpr section@(SectionR op expr)
- = rnLExpr op `thenM` \ (op', fvs_op) ->
- rnLExpr expr `thenM` \ (expr', fvs_expr) ->
- checkSectionPrec InfixR section op' expr' `thenM_`
- returnM (SectionR op' expr', fvs_op `plusFV` fvs_expr)
-
-rnExpr (HsCoreAnn ann expr)
- = rnLExpr expr `thenM` \ (expr', fvs_expr) ->
- returnM (HsCoreAnn ann expr', fvs_expr)
-
-rnExpr (HsSCC lbl expr)
- = rnLExpr expr `thenM` \ (expr', fvs_expr) ->
- returnM (HsSCC lbl expr', fvs_expr)
-
-rnExpr (HsLam matches)
- = rnMatchGroup LambdaExpr matches `thenM` \ (matches', fvMatch) ->
- returnM (HsLam matches', fvMatch)
-
-rnExpr (HsCase expr matches)
- = rnLExpr expr `thenM` \ (new_expr, e_fvs) ->
- rnMatchGroup CaseAlt matches `thenM` \ (new_matches, ms_fvs) ->
- returnM (HsCase new_expr new_matches, e_fvs `plusFV` ms_fvs)
-
-rnExpr (HsLet binds expr)
- = rnLocalBindsAndThen binds $ \ binds' ->
- rnLExpr expr `thenM` \ (expr',fvExpr) ->
- returnM (HsLet binds' expr', fvExpr)
-
-rnExpr e@(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) ->
- returnM (ExplicitList placeHolderType exps', fvs `addOneFV` listTyCon_name)
-
-rnExpr (ExplicitPArr _ exps)
- = rnExprs exps `thenM` \ (exps', fvs) ->
- returnM (ExplicitPArr placeHolderType 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
- tup_size = length exps
- tycon_name = tupleTyCon_name boxity tup_size
-
-rnExpr (RecordCon con_id _ rbinds)
- = lookupLocatedOccRn con_id `thenM` \ conname ->
- rnRbinds "construction" rbinds `thenM` \ (rbinds', fvRbinds) ->
- returnM (RecordCon conname noPostTcExpr rbinds',
- fvRbinds `addOneFV` unLoc conname)
-
-rnExpr (RecordUpd expr rbinds _ _)
- = rnLExpr expr `thenM` \ (expr', fvExpr) ->
- rnRbinds "update" rbinds `thenM` \ (rbinds', fvRbinds) ->
- returnM (RecordUpd expr' rbinds' placeHolderType placeHolderType,
- fvExpr `plusFV` fvRbinds)
-
-rnExpr (ExprWithTySig expr pty)
- = rnLExpr expr `thenM` \ (expr', fvExpr) ->
- rnHsTypeFVs doc pty `thenM` \ (pty', fvTy) ->
- returnM (ExprWithTySig expr' pty', fvExpr `plusFV` fvTy)
- where
- doc = text "In an expression type signature"
-
-rnExpr (HsIf p b1 b2)
- = rnLExpr p `thenM` \ (p', fvP) ->
- rnLExpr b1 `thenM` \ (b1', fvB1) ->
- rnLExpr b2 `thenM` \ (b2', fvB2) ->
- returnM (HsIf p' b1' b2', plusFVs [fvP, fvB1, fvB2])
-
-rnExpr (HsType a)
- = rnHsTypeFVs doc a `thenM` \ (t, fvT) ->
- returnM (HsType t, fvT)
- where
- doc = text "In a type argument"
-
-rnExpr (ArithSeq _ seq)
- = rnArithSeq seq `thenM` \ (new_seq, fvs) ->
- returnM (ArithSeq noPostTcExpr new_seq, fvs)
-
-rnExpr (PArrSeq _ seq)
- = rnArithSeq seq `thenM` \ (new_seq, fvs) ->
- returnM (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@(ELazyPat {}) = patSynErr e
-\end{code}
-
-%************************************************************************
-%* *
- Arrow notation
-%* *
-%************************************************************************
-
-\begin{code}
-rnExpr (HsProc pat body)
- = newArrowScope $
- rnPatsAndThen ProcExpr [pat] $ \ [pat'] ->
- rnCmdTop body `thenM` \ (body',fvBody) ->
- returnM (HsProc pat' body', fvBody)
-
-rnExpr (HsArrApp arrow arg _ ho rtl)
- = select_arrow_scope (rnLExpr arrow) `thenM` \ (arrow',fvArrow) ->
- rnLExpr arg `thenM` \ (arg',fvArg) ->
- returnM (HsArrApp arrow' arg' placeHolderType ho rtl,
- fvArrow `plusFV` fvArg)
- where
- select_arrow_scope tc = case ho of
- HsHigherOrderApp -> tc
- HsFirstOrderApp -> escapeArrowScope tc
-
--- infix form
-rnExpr (HsArrForm op (Just _) [arg1, arg2])
- = escapeArrowScope (rnLExpr op)
- `thenM` \ (op'@(L _ (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)
- = escapeArrowScope (rnLExpr op) `thenM` \ (op',fvOp) ->
- rnCmdArgs cmds `thenM` \ (cmds',fvCmds) ->
- returnM (HsArrForm op' fixity cmds', fvOp `plusFV` fvCmds)
-
-rnExpr other = pprPanic "rnExpr: unexpected expression" (ppr other)
- -- DictApp, DictLam, TyApp, TyLam
-\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 = wrapLocFstM rnCmdTop'
- where
- rnCmdTop' (HsCmdTop cmd _ _ _)
- = rnLExpr (convertOpFormsLCmd cmd) `thenM` \ (cmd', fvCmd) ->
- let
- cmd_names = [arrAName, composeAName, firstAName] ++
- nameSetToList (methodNamesCmd (unLoc cmd'))
- in
- -- Generate the rebindable syntax for the monad
- lookupSyntaxTable 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
-
-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)
-
--- gaw 2004
-convertOpFormsCmd (HsCase exp matches)
- = HsCase exp (convertOpFormsMatch matches)
-
-convertOpFormsCmd (HsIf exp c1 c2)
- = HsIf 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
-
--- 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 _ _)
- = 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 = stmt
-
-convertOpFormsMatch (MatchGroup ms ty)
- = MatchGroup (map (fmap convert) ms) ty
- where convert (Match pat mty grhss)
- = Match pat mty (convertOpFormsGRHSs grhss)
-
-convertOpFormsGRHSs (GRHSs grhss binds)
- = GRHSs (map convertOpFormsGRHS grhss) binds
-
-convertOpFormsGRHS = fmap convert
- where
- convert (GRHS stmts cmd) = GRHS stmts (convertOpFormsLCmd cmd)
-
----------------------------------------------------
-type CmdNeeds = FreeVars -- Only inhabitants are
- -- appAName, choiceAName, loopAName
-
--- find what methods the Cmd needs (loop, choice, apply)
-methodNamesLCmd :: LHsCmd Name -> CmdNeeds
-methodNamesLCmd = methodNamesCmd . unLoc
-
-methodNamesCmd :: HsCmd Name -> CmdNeeds
-
-methodNamesCmd cmd@(HsArrApp _arrow _arg _ HsFirstOrderApp _rtl)
- = emptyFVs
-methodNamesCmd cmd@(HsArrApp _arrow _arg _ HsHigherOrderApp _rtl)
- = unitFV appAName
-methodNamesCmd cmd@(HsArrForm {}) = emptyFVs
-
-methodNamesCmd (HsPar c) = methodNamesLCmd c
-
-methodNamesCmd (HsIf p c1 c2)
- = methodNamesLCmd c1 `plusFV` methodNamesLCmd c2 `addOneFV` choiceAName
-
-methodNamesCmd (HsLet b c) = methodNamesLCmd c
-
-methodNamesCmd (HsDo sc stmts body ty)
- = methodNamesStmts stmts `plusFV` methodNamesLCmd body
-
-methodNamesCmd (HsApp c e) = methodNamesLCmd c
-
-methodNamesCmd (HsLam match) = methodNamesMatch match
-
-methodNamesCmd (HsCase scrut matches)
- = 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 (MatchGroup ms ty)
- = plusFVs (map do_one ms)
- where
- do_one (L _ (Match pats sig_ty grhss)) = methodNamesGRHSs grhss
-
--------------------------------------------------
--- gaw 2004
-methodNamesGRHSs (GRHSs grhss binds) = plusFVs (map methodNamesGRHS grhss)
-
--------------------------------------------------
-methodNamesGRHS (L _ (GRHS stmts rhs)) = methodNamesLCmd rhs
-
----------------------------------------------------
-methodNamesStmts stmts = plusFVs (map methodNamesLStmt stmts)
-
----------------------------------------------------
-methodNamesLStmt = methodNamesStmt . unLoc
-
-methodNamesStmt (ExprStmt cmd _ _) = methodNamesLCmd cmd
-methodNamesStmt (BindStmt pat cmd _ _) = methodNamesLCmd cmd
-methodNamesStmt (RecStmt stmts _ _ _ _)
- = methodNamesStmts stmts `addOneFV` loopAName
-methodNamesStmt (LetStmt b) = emptyFVs
-methodNamesStmt (ParStmt ss) = emptyFVs
- -- ParStmt can't occur in commands, but it's not convenient to error
- -- here so we just do what's convenient
-\end{code}
-
-
-%************************************************************************
-%* *
- Arithmetic sequences
-%* *
-%************************************************************************
-
-\begin{code}
-rnArithSeq (From expr)
- = rnLExpr expr `thenM` \ (expr', fvExpr) ->
- returnM (From expr', fvExpr)
-
-rnArithSeq (FromThen expr1 expr2)
- = rnLExpr expr1 `thenM` \ (expr1', fvExpr1) ->
- rnLExpr expr2 `thenM` \ (expr2', fvExpr2) ->
- returnM (FromThen expr1' expr2', fvExpr1 `plusFV` fvExpr2)
-
-rnArithSeq (FromTo expr1 expr2)
- = rnLExpr expr1 `thenM` \ (expr1', fvExpr1) ->
- rnLExpr expr2 `thenM` \ (expr2', fvExpr2) ->
- returnM (FromTo expr1' expr2', fvExpr1 `plusFV` fvExpr2)
-
-rnArithSeq (FromThenTo expr1 expr2 expr3)
- = rnLExpr expr1 `thenM` \ (expr1', fvExpr1) ->
- rnLExpr expr2 `thenM` \ (expr2', fvExpr2) ->
- rnLExpr expr3 `thenM` \ (expr3', fvExpr3) ->
- returnM (FromThenTo expr1' expr2' expr3',
- plusFVs [fvExpr1, fvExpr2, fvExpr3])
-\end{code}
-
-
-%************************************************************************
-%* *
-\subsubsection{@Rbinds@s and @Rpats@s: in record expressions}
-%* *
-%************************************************************************
-
-\begin{code}
-rnRbinds str rbinds
- = mappM_ field_dup_err dup_fields `thenM_`
- mapFvRn rn_rbind rbinds `thenM` \ (rbinds', fvRbind) ->
- returnM (rbinds', fvRbind)
- where
- (_, dup_fields) = removeDups cmpLocated [ f | (f,_) <- rbinds ]
-
- field_dup_err dups = mappM_ (\f -> addLocErr f (dupFieldErr str)) dups
-
- rn_rbind (field, expr)
- = lookupLocatedGlobalOccRn field `thenM` \ fieldname ->
- rnLExpr expr `thenM` \ (expr', fvExpr) ->
- returnM ((fieldname, expr'), fvExpr `addOneFV` unLoc fieldname)
-\end{code}
-
-%************************************************************************
-%* *
- Template Haskell brackets
-%* *
-%************************************************************************
-
-\begin{code}
-rnBracket (VarBr n) = do { name <- lookupOccRn n
- ; this_mod <- getModule
- ; checkM (nameIsLocalOrFrom this_mod name) $ -- Reason: deprecation checking asumes the
- do { loadHomeInterface msg name -- home interface is loaded, and this is the
- ; return () } -- only way that is going to happen
- ; returnM (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) = do { (p', fvs) <- rnLPat p
- ; return (PatBr p', fvs) }
-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 gbl_env1 = gbl_env { tcg_mod = thFAKE }
- -- Note the thFAKE. The top-level names from the bracketed
- -- declarations will go into the name cache, and we don't want them to
- -- confuse the Names for the current module.
- -- By using a pretend module, thFAKE, we keep them safely out of the way.
-
- ; names <- getLocalDeclBinders gbl_env1 group
- ; rdr_env' <- extendRdrEnvRn emptyGlobalRdrEnv names
- -- Furthermore, the names in the bracket shouldn't conflict with
- -- existing top-level names E.g.
- -- foo = 1
- -- bar = [d| foo = 1|]
- -- But both 'foo's get a LocalDef provenance, so we'd get a complaint unless
- -- we start with an emptyGlobalRdrEnv
-
- ; setGblEnv (gbl_env { tcg_rdr_env = tcg_rdr_env gbl_env1 `plusOccEnv` rdr_env',
- tcg_dus = emptyDUs }) $ do
- -- Notice plusOccEnv, not plusGlobalRdrEnv. In this situation we want
- -- to *shadow* top-level bindings. (See the 'foo' example above.)
- -- If we don't shadow, we'll get an ambiguity complaint when we do
- -- a lookupTopBndrRn (which uses lookupGreLocalRn) on the binder of the 'foo'
- --
- -- Furthermore, arguably if the splice does define foo, that should hide
- -- any foo's further out
- --
- -- The emptyDUs is so that we just collect uses for this group alone
-
- { (tcg_env, group') <- rnSrcDecls group
- -- Discard the tcg_env; it contains only extra info about fixity
- ; return (DecBr group', allUses (tcg_dus tcg_env)) } }
-\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 _) = rnMDoStmts
-rnStmts ctxt = rnNormalStmts ctxt
-
-rnNormalStmts :: HsStmtContext Name -> [LStmt RdrName]
- -> RnM (thing, FreeVars)
- -> RnM (([LStmt Name], thing), FreeVars)
--- Used for cases *other* than recursive mdo
--- Implements nested scopes
-
-rnNormalStmts ctxt [] thing_inside
- = do { (thing, fvs) <- thing_inside
- ; return (([],thing), fvs) }
-
-rnNormalStmts ctxt (L loc stmt : stmts) thing_inside
- = do { ((stmt', (stmts', thing)), fvs)
- <- rnStmt ctxt stmt $
- rnNormalStmts ctxt stmts thing_inside
- ; return (((L loc stmt' : stmts'), thing), fvs) }
-
-rnStmt :: HsStmtContext Name -> Stmt RdrName
- -> RnM (thing, FreeVars)
- -> RnM ((Stmt Name, thing), FreeVars)
-
-rnStmt ctxt (ExprStmt expr _ _) thing_inside
- = do { (expr', fv_expr) <- rnLExpr expr
- ; (then_op, fvs1) <- lookupSyntaxName thenMName
- ; (thing, fvs2) <- thing_inside
- ; return ((ExprStmt expr' then_op placeHolderType, thing),
- fv_expr `plusFV` fvs1 `plusFV` fvs2) }
-
-rnStmt ctxt (BindStmt pat expr _ _) thing_inside
- = 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 (StmtCtxt ctxt) [pat] $ \ [pat'] -> do
- { (thing, fvs3) <- thing_inside
- ; return ((BindStmt pat' expr' bind_op fail_op, thing),
- fv_expr `plusFV` fvs1 `plusFV` fvs2 `plusFV` fvs3) }}
- -- fv_expr shouldn't really be filtered by the rnPatsAndThen
- -- but it does not matter because the names are unique
-
-rnStmt ctxt (LetStmt binds) thing_inside
- = do { checkErr (ok ctxt binds)
- (badIpBinds (ptext SLIT("a parallel list comprehension:")) binds)
- ; rnLocalBindsAndThen binds $ \ binds' -> do
- { (thing, fvs) <- thing_inside
- ; return ((LetStmt binds', thing), fvs) }}
- where
- -- We do not allow implicit-parameter bindings in a parallel
- -- list comprehension. I'm not sure what it might mean.
- ok (ParStmtCtxt _) (HsIPBinds _) = False
- ok _ _ = True
-
-rnStmt ctxt (RecStmt rec_stmts _ _ _ _) thing_inside
- = bindLocatedLocalsRn doc (collectLStmtsBinders rec_stmts) $ \ bndrs ->
- rn_rec_stmts bndrs rec_stmts `thenM` \ segs ->
- thing_inside `thenM` \ (thing, fvs) ->
- let
- segs_w_fwd_refs = addFwdRefs segs
- (ds, us, fs, rec_stmts') = unzip4 segs_w_fwd_refs
- later_vars = nameSetToList (plusFVs ds `intersectNameSet` fvs)
- fwd_vars = nameSetToList (plusFVs fs)
- uses = plusFVs us
- rec_stmt = RecStmt rec_stmts' later_vars fwd_vars [] emptyLHsBinds
- in
- returnM ((rec_stmt, thing), uses `plusFV` fvs)
- where
- doc = text "In a recursive do statement"
-
-rnStmt ctxt (ParStmt segs) thing_inside
- = do { opt_GlasgowExts <- doptM Opt_GlasgowExts
- ; checkM opt_GlasgowExts parStmtErr
- ; orig_lcl_env <- getLocalRdrEnv
- ; ((segs',thing), fvs) <- go orig_lcl_env [] segs
- ; return ((ParStmt segs', thing), fvs) }
- where
--- type ParSeg id = [([LStmt id], [id])]
--- go :: NameSet -> [ParSeg RdrName]
--- -> RnM (([ParSeg Name], thing), FreeVars)
-
- go orig_lcl_env bndrs []
- = do { let { (bndrs', dups) = removeDups cmpByOcc bndrs
- ; inner_env = extendLocalRdrEnv orig_lcl_env bndrs' }
- ; mappM dupErr dups
- ; (thing, fvs) <- setLocalRdrEnv inner_env thing_inside
- ; return (([], thing), fvs) }
-
- go orig_lcl_env bndrs_so_far ((stmts, _) : segs)
- = do { ((stmts', (bndrs, segs', thing)), fvs)
- <- rnNormalStmts par_ctxt stmts $ do
- { -- Find the Names that are bound by stmts
- lcl_env <- getLocalRdrEnv
- ; let { rdr_bndrs = collectLStmtsBinders stmts
- ; bndrs = map ( expectJust "rnStmt"
- . lookupLocalRdrEnv lcl_env
- . unLoc) rdr_bndrs
- ; new_bndrs = nub bndrs ++ bndrs_so_far
- -- The nub is because there might be shadowing
- -- x <- e1; x <- e2
- -- So we'll look up (Unqual x) twice, getting
- -- the second binding both times, which is the
- } -- one we want
-
- -- Typecheck the thing inside, passing on all
- -- the Names bound, but separately; revert the envt
- ; ((segs', thing), fvs) <- setLocalRdrEnv orig_lcl_env $
- go orig_lcl_env new_bndrs segs
-
- -- Figure out which of the bound names are used
- ; let used_bndrs = filter (`elemNameSet` fvs) bndrs
- ; return ((used_bndrs, segs', thing), fvs) }
-
- ; let seg' = (stmts', bndrs)
- ; return (((seg':segs'), thing),
- delListFromNameSet fvs bndrs) }
-
- par_ctxt = ParStmtCtxt ctxt
-
- cmpByOcc n1 n2 = nameOccName n1 `compare` nameOccName n2
- dupErr vs = addErr (ptext SLIT("Duplicate binding in parallel list comprehension for:")
- <+> quotes (ppr (head vs)))
-\end{code}
-
-
-%************************************************************************
-%* *
-\subsubsection{mdo expressions}
-%* *
-%************************************************************************
-
-\begin{code}
-type FwdRefs = NameSet
-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
- 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
- bindLocatedLocalsRn doc (collectLStmtsBinders stmts) $ \ bndrs ->
- do {
- -- 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.)
- segs <- rn_rec_stmts bndrs stmts
-
- ; (thing, fvs_later) <- thing_inside
-
- ; 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', fvs) = segsToStmts grouped_segs fvs_later
-
- ; return ((stmts', thing), fvs) }
- where
- doc = text "In a recursive mdo-expression"
-
----------------------------------------------
-rn_rec_stmts :: [Name] -> [LStmt RdrName] -> RnM [Segment (LStmt Name)]
-rn_rec_stmts bndrs stmts = mappM (rn_rec_stmt bndrs) stmts `thenM` \ segs_s ->
- returnM (concat segs_s)
-
-----------------------------------------------------
-rn_rec_stmt :: [Name] -> LStmt RdrName -> RnM [Segment (LStmt Name)]
- -- Rename a Stmt that is inside a RecStmt (or mdo)
- -- Assumes all binders are already in scope
- -- Turns each stmt into a singleton Stmt
-
-rn_rec_stmt all_bndrs (L loc (ExprStmt expr _ _))
- = rnLExpr expr `thenM` \ (expr', fvs) ->
- lookupSyntaxName thenMName `thenM` \ (then_op, fvs1) ->
- returnM [(emptyNameSet, fvs `plusFV` fvs1, emptyNameSet,
- L loc (ExprStmt expr' then_op placeHolderType))]
-
-rn_rec_stmt all_bndrs (L loc (BindStmt pat expr _ _))
- = rnLExpr expr `thenM` \ (expr', fv_expr) ->
- rnLPat pat `thenM` \ (pat', fv_pat) ->
- 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
- returnM [(bndrs, fvs, bndrs `intersectNameSet` fvs,
- L loc (BindStmt pat' expr' bind_op fail_op))]
-
-rn_rec_stmt all_bndrs (L loc (LetStmt binds@(HsIPBinds _)))
- = do { addErr (badIpBinds (ptext SLIT("an mdo expression")) binds)
- ; failM }
-
-rn_rec_stmt all_bndrs (L loc (LetStmt (HsValBinds binds)))
- = rnValBinds (trimWith all_bndrs) binds `thenM` \ (binds', du_binds) ->
- returnM [(duDefs du_binds, duUses du_binds,
- emptyNameSet, L loc (LetStmt (HsValBinds binds')))]
-
-rn_rec_stmt all_bndrs (L loc (RecStmt stmts _ _ _ _)) -- Flatten Rec inside Rec
- = rn_rec_stmts all_bndrs stmts
-
-rn_rec_stmt all_bndrs stmt@(L _ (ParStmt _)) -- Syntactically illegal in mdo
- = pprPanic "rn_rec_stmt" (ppr stmt)
-
----------------------------------------------
-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, 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)
- -- Add the downstream fwd refs here
-
-----------------------------------------------------
--- 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...
--- p <- z
--- y <- ...x...
--- q <- x
--- 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 }
--- Now one more... but this time we have to group a bunch into rec
--- { rec { y <- ...x... ; q <- x ; z <- y } ; r <- x }
--- Now one more, which we can add on without a rec
--- { p <- z ;
--- rec { y <- ...x... ; q <- x ; z <- y } ;
--- r <- x }
--- Finally we add the last one; since it mentions y we have to
--- glom it togeher with the first two groups
--- { rec { x <- ...y...; p <- z ; y <- ...x... ;
--- q <- x ; z <- y } ;
--- r <- x }
-
-glomSegments :: [Segment (LStmt Name)] -> [Segment [LStmt Name]]
-
-glomSegments [] = []
-glomSegments ((defs,uses,fwds,stmt) : segs)
- -- Actually stmts will always be a singleton
- = (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 -- 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)
- where
- (noes, yeses) = span not_needed (reverse dus)
- not_needed (defs,_,_,_) = not (intersectsNameSet defs uses)
-
-
-----------------------------------------------------
-segsToStmts :: [Segment [LStmt Name]]
- -> FreeVars -- Free vars used 'later'
- -> ([LStmt Name], FreeVars)
-
-segsToStmts [] fvs_later = ([], fvs_later)
-segsToStmts ((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
- 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
- -- The ones needed after the RecStmt
-\end{code}
-
-%************************************************************************
-%* *
-\subsubsection{breakpoint utils}
-%* *
-%************************************************************************
-
-\begin{code}
-#if defined(GHCI) && defined(BREAKPOINT)
-mkBreakPointExpr :: [Name] -> RnM (HsExpr Name, FreeVars)
-mkBreakPointExpr scope
- = do sloc <- getSrcSpanM
- undef <- lookupOccRn undefined_RDR
- let inLoc = L sloc
- lHsApp x y = inLoc (HsApp x y)
- mkExpr fnName args = mkExpr' fnName (reverse args)
- mkExpr' fnName [] = inLoc (HsVar fnName)
- mkExpr' fnName (arg:args)
- = lHsApp (mkExpr' fnName args) (inLoc arg)
- expr = unLoc $ mkExpr breakpointJumpName [mkScopeArg scope, HsVar undef, HsLit msg]
- mkScopeArg args
- = unLoc $ mkExpr undef (map HsVar args)
- msg = HsString (mkFastString (unpackFS (srcSpanFile sloc) ++ ":" ++ show (srcSpanStartLine sloc)))
- return (expr, emptyFVs)
-#endif
-\end{code}
-
-%************************************************************************
-%* *
-\subsubsection{Assertion utils}
-%* *
-%************************************************************************
-
-\begin{code}
-mkAssertErrorExpr :: RnM (HsExpr Name, FreeVars)
--- Return an expression for (assertError "Foo.hs:27")
-mkAssertErrorExpr
- = getSrcSpanM `thenM` \ sloc ->
- let
- expr = HsApp (L sloc (HsVar assertErrorName)) (L sloc (HsLit msg))
- msg = HsStringPrim (mkFastString (showSDoc (ppr sloc)))
- in
- returnM (expr, emptyFVs)
-\end{code}
-
-%************************************************************************
-%* *
-\subsubsection{Errors}
-%* *
-%************************************************************************
-
-\begin{code}
-patSynErr e = do { addErr (sep [ptext SLIT("Pattern syntax in expression context:"),
- nest 4 (ppr e)])
- ; return (EWildPat, emptyFVs) }
-
-parStmtErr = addErr (ptext SLIT("Illegal parallel list comprehension: use -fglasgow-exts"))
-
-badIpBinds what binds
- = hang (ptext SLIT("Implicit-parameter bindings illegal in") <+> what)
- 2 (ppr binds)
-\end{code}
projects / ghc-hetmet.git / blobdiff