2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[RnExpr]{Renaming of expressions}
6 Basically dependency analysis.
8 Handles @Match@, @GRHSs@, @HsExpr@, and @Qualifier@ datatypes. In
9 general, all of these functions return a renamed thing, and a set of
14 rnMatch, rnGRHSs, rnPat, rnExpr, rnExprs,
18 #include "HsVersions.h"
20 import {-# SOURCE #-} RnBinds ( rnBinds )
21 import {-# SOURCE #-} RnSource ( rnHsTypeFVs )
28 import RnHiFiles ( lookupFixityRn )
29 import CmdLineOpts ( DynFlag(..), opt_IgnoreAsserts )
30 import Literal ( inIntRange )
31 import BasicTypes ( Fixity(..), FixityDirection(..), defaultFixity, negateFixity )
32 import PrelNames ( hasKey, assertIdKey, minusName, negateName, fromIntName,
33 eqClass_RDR, foldr_RDR, build_RDR, eqString_RDR,
34 cCallableClass_RDR, cReturnableClass_RDR,
35 monadClass_RDR, enumClass_RDR, ordClass_RDR,
36 ratioDataCon_RDR, assertErr_RDR,
37 ioDataCon_RDR, plusInteger_RDR, timesInteger_RDR,
38 fromInteger_RDR, fromRational_RDR,
40 import TysPrim ( charPrimTyCon, addrPrimTyCon, intPrimTyCon,
41 floatPrimTyCon, doublePrimTyCon
43 import TysWiredIn ( intTyCon )
44 import Name ( NamedThing(..), mkSysLocalName, nameSrcLoc )
46 import UniqFM ( isNullUFM )
47 import FiniteMap ( elemFM )
48 import UniqSet ( emptyUniqSet )
49 import List ( intersectBy )
50 import ListSetOps ( unionLists, removeDups )
51 import Maybes ( maybeToBool )
56 *********************************************************
60 *********************************************************
63 rnPat :: RdrNamePat -> RnMS (RenamedPat, FreeVars)
65 rnPat WildPatIn = returnRn (WildPatIn, emptyFVs)
68 = lookupBndrRn name `thenRn` \ vname ->
69 returnRn (VarPatIn vname, emptyFVs)
71 rnPat (SigPatIn pat ty)
72 = doptRn Opt_GlasgowExts `thenRn` \ glaExts ->
75 then rnPat pat `thenRn` \ (pat', fvs1) ->
76 rnHsTypeFVs doc ty `thenRn` \ (ty', fvs2) ->
77 returnRn (SigPatIn pat' ty', fvs1 `plusFV` fvs2)
79 else addErrRn (patSigErr ty) `thenRn_`
82 doc = text "a pattern type-signature"
84 rnPat (LitPatIn s@(HsString _))
85 = lookupOrigName eqString_RDR `thenRn` \ eq ->
86 returnRn (LitPatIn s, unitFV eq)
89 = litFVs lit `thenRn` \ fvs ->
90 returnRn (LitPatIn lit, fvs)
93 = rnOverLit lit `thenRn` \ (lit', fvs1) ->
94 lookupOrigName eqClass_RDR `thenRn` \ eq -> -- Needed to find equality on pattern
95 returnRn (NPatIn lit', fvs1 `addOneFV` eq)
97 rnPat (NPlusKPatIn name lit)
98 = rnOverLit lit `thenRn` \ (lit', fvs) ->
99 lookupOrigName ordClass_RDR `thenRn` \ ord ->
100 lookupBndrRn name `thenRn` \ name' ->
101 returnRn (NPlusKPatIn name' lit', fvs `addOneFV` ord `addOneFV` minusName)
103 rnPat (LazyPatIn pat)
104 = rnPat pat `thenRn` \ (pat', fvs) ->
105 returnRn (LazyPatIn pat', fvs)
107 rnPat (AsPatIn name pat)
108 = rnPat pat `thenRn` \ (pat', fvs) ->
109 lookupBndrRn name `thenRn` \ vname ->
110 returnRn (AsPatIn vname pat', fvs)
112 rnPat (ConPatIn con pats)
113 = lookupOccRn con `thenRn` \ con' ->
114 mapFvRn rnPat pats `thenRn` \ (patslist, fvs) ->
115 returnRn (ConPatIn con' patslist, fvs `addOneFV` con')
117 rnPat (ConOpPatIn pat1 con _ pat2)
118 = rnPat pat1 `thenRn` \ (pat1', fvs1) ->
119 lookupOccRn con `thenRn` \ con' ->
120 rnPat pat2 `thenRn` \ (pat2', fvs2) ->
122 getModeRn `thenRn` \ mode ->
123 -- See comments with rnExpr (OpApp ...)
124 (if isInterfaceMode mode
125 then returnRn (ConOpPatIn pat1' con' defaultFixity pat2')
126 else lookupFixityRn con' `thenRn` \ fixity ->
127 mkConOpPatRn pat1' con' fixity pat2'
129 returnRn (pat', fvs1 `plusFV` fvs2 `addOneFV` con')
132 = rnPat pat `thenRn` \ (pat', fvs) ->
133 returnRn (ParPatIn pat', fvs)
135 rnPat (ListPatIn pats)
136 = mapFvRn rnPat pats `thenRn` \ (patslist, fvs) ->
137 returnRn (ListPatIn patslist, fvs `addOneFV` listTyCon_name)
139 rnPat (TuplePatIn pats boxed)
140 = mapFvRn rnPat pats `thenRn` \ (patslist, fvs) ->
141 returnRn (TuplePatIn patslist boxed, fvs `addOneFV` tycon_name)
143 tycon_name = tupleTyCon_name boxed (length pats)
145 rnPat (RecPatIn con rpats)
146 = lookupOccRn con `thenRn` \ con' ->
147 rnRpats rpats `thenRn` \ (rpats', fvs) ->
148 returnRn (RecPatIn con' rpats', fvs `addOneFV` con')
149 rnPat (TypePatIn name) =
150 (rnHsTypeFVs (text "type pattern") name) `thenRn` \ (name', fvs) ->
151 returnRn (TypePatIn name', fvs)
154 ************************************************************************
158 ************************************************************************
161 rnMatch :: RdrNameMatch -> RnMS (RenamedMatch, FreeVars)
163 rnMatch match@(Match _ pats maybe_rhs_sig grhss)
164 = pushSrcLocRn (getMatchLoc match) $
166 -- Find the universally quantified type variables
167 -- in the pattern type signatures
168 getLocalNameEnv `thenRn` \ name_env ->
170 tyvars_in_sigs = rhs_sig_tyvars `unionLists` tyvars_in_pats
171 rhs_sig_tyvars = case maybe_rhs_sig of
173 Just ty -> extractHsTyRdrTyVars ty
174 tyvars_in_pats = extractPatsTyVars pats
175 forall_tyvars = filter (not . (`elemFM` name_env)) tyvars_in_sigs
176 doc_sig = text "a pattern type-signature"
177 doc_pats = text "a pattern match"
179 bindNakedTyVarsFVRn doc_sig forall_tyvars $ \ sig_tyvars ->
181 -- Note that we do a single bindLocalsRn for all the
182 -- matches together, so that we spot the repeated variable in
184 bindLocalsFVRn doc_pats (collectPatsBinders pats) $ \ new_binders ->
186 mapFvRn rnPat pats `thenRn` \ (pats', pat_fvs) ->
187 rnGRHSs grhss `thenRn` \ (grhss', grhss_fvs) ->
188 doptRn Opt_GlasgowExts `thenRn` \ opt_GlasgowExts ->
189 (case maybe_rhs_sig of
190 Nothing -> returnRn (Nothing, emptyFVs)
191 Just ty | opt_GlasgowExts -> rnHsTypeFVs doc_sig ty `thenRn` \ (ty', ty_fvs) ->
192 returnRn (Just ty', ty_fvs)
193 | otherwise -> addErrRn (patSigErr ty) `thenRn_`
194 returnRn (Nothing, emptyFVs)
195 ) `thenRn` \ (maybe_rhs_sig', ty_fvs) ->
198 binder_set = mkNameSet new_binders
199 unused_binders = nameSetToList (binder_set `minusNameSet` grhss_fvs)
200 all_fvs = grhss_fvs `plusFV` pat_fvs `plusFV` ty_fvs
202 warnUnusedMatches unused_binders `thenRn_`
204 returnRn (Match sig_tyvars pats' maybe_rhs_sig' grhss', all_fvs)
205 -- The bindLocals and bindTyVars will remove the bound FVs
208 %************************************************************************
210 \subsubsection{Guarded right-hand sides (GRHSs)}
212 %************************************************************************
215 rnGRHSs :: RdrNameGRHSs -> RnMS (RenamedGRHSs, FreeVars)
217 rnGRHSs (GRHSs grhss binds maybe_ty)
218 = ASSERT( not (maybeToBool maybe_ty) )
219 rnBinds binds $ \ binds' ->
220 mapFvRn rnGRHS grhss `thenRn` \ (grhss', fvGRHSs) ->
221 returnRn (GRHSs grhss' binds' Nothing, fvGRHSs)
223 rnGRHS (GRHS guarded locn)
224 = doptRn Opt_GlasgowExts `thenRn` \ opt_GlasgowExts ->
226 (if not (opt_GlasgowExts || is_standard_guard guarded) then
227 addWarnRn (nonStdGuardErr guarded)
232 rnStmts rnExpr guarded `thenRn` \ ((_, guarded'), fvs) ->
233 returnRn (GRHS guarded' locn, fvs)
235 -- Standard Haskell 1.4 guards are just a single boolean
236 -- expression, rather than a list of qualifiers as in the
238 is_standard_guard [ExprStmt _ _] = True
239 is_standard_guard [GuardStmt _ _, ExprStmt _ _] = True
240 is_standard_guard other = False
243 %************************************************************************
245 \subsubsection{Expressions}
247 %************************************************************************
250 rnExprs :: [RdrNameHsExpr] -> RnMS ([RenamedHsExpr], FreeVars)
251 rnExprs ls = rnExprs' ls emptyUniqSet
253 rnExprs' [] acc = returnRn ([], acc)
254 rnExprs' (expr:exprs) acc
255 = rnExpr expr `thenRn` \ (expr', fvExpr) ->
257 -- Now we do a "seq" on the free vars because typically it's small
258 -- or empty, especially in very long lists of constants
260 acc' = acc `plusFV` fvExpr
262 (grubby_seqNameSet acc' rnExprs') exprs acc' `thenRn` \ (exprs', fvExprs) ->
263 returnRn (expr':exprs', fvExprs)
265 -- Grubby little function to do "seq" on namesets; replace by proper seq when GHC can do seq
266 grubby_seqNameSet ns result | isNullUFM ns = result
270 Variables. We look up the variable and return the resulting name.
273 rnExpr :: RdrNameHsExpr -> RnMS (RenamedHsExpr, FreeVars)
276 = lookupOccRn v `thenRn` \ name ->
277 if name `hasKey` assertIdKey then
278 -- We expand it to (GHCerr.assert__ location)
282 returnRn (HsVar name, unitFV name)
285 = newIPName v `thenRn` \ name ->
286 returnRn (HsIPVar name, emptyFVs)
289 = litFVs lit `thenRn` \ fvs ->
290 returnRn (HsLit lit, fvs)
292 rnExpr (HsOverLit lit)
293 = rnOverLit lit `thenRn` \ (lit', fvs) ->
294 returnRn (HsOverLit lit', fvs)
297 = rnMatch match `thenRn` \ (match', fvMatch) ->
298 returnRn (HsLam match', fvMatch)
300 rnExpr (HsApp fun arg)
301 = rnExpr fun `thenRn` \ (fun',fvFun) ->
302 rnExpr arg `thenRn` \ (arg',fvArg) ->
303 returnRn (HsApp fun' arg', fvFun `plusFV` fvArg)
305 rnExpr (OpApp e1 op _ e2)
306 = rnExpr e1 `thenRn` \ (e1', fv_e1) ->
307 rnExpr e2 `thenRn` \ (e2', fv_e2) ->
308 rnExpr op `thenRn` \ (op'@(HsVar op_name), fv_op) ->
311 -- When renaming code synthesised from "deriving" declarations
312 -- we're in Interface mode, and we should ignore fixity; assume
313 -- that the deriving code generator got the association correct
314 -- Don't even look up the fixity when in interface mode
315 getModeRn `thenRn` \ mode ->
316 (if isInterfaceMode mode
317 then returnRn (OpApp e1' op' defaultFixity e2')
318 else lookupFixityRn op_name `thenRn` \ fixity ->
319 mkOpAppRn e1' op' fixity e2'
320 ) `thenRn` \ final_e ->
323 fv_e1 `plusFV` fv_op `plusFV` fv_e2)
326 = rnExpr e `thenRn` \ (e', fv_e) ->
327 mkNegAppRn e' `thenRn` \ final_e ->
328 returnRn (final_e, fv_e `addOneFV` negateName)
331 = rnExpr e `thenRn` \ (e', fvs_e) ->
332 returnRn (HsPar e', fvs_e)
334 rnExpr section@(SectionL expr op)
335 = rnExpr expr `thenRn` \ (expr', fvs_expr) ->
336 rnExpr op `thenRn` \ (op', fvs_op) ->
337 checkSectionPrec "left" section op' expr' `thenRn_`
338 returnRn (SectionL expr' op', fvs_op `plusFV` fvs_expr)
340 rnExpr section@(SectionR op expr)
341 = rnExpr op `thenRn` \ (op', fvs_op) ->
342 rnExpr expr `thenRn` \ (expr', fvs_expr) ->
343 checkSectionPrec "right" section op' expr' `thenRn_`
344 returnRn (SectionR op' expr', fvs_op `plusFV` fvs_expr)
346 rnExpr (HsCCall fun args may_gc is_casm fake_result_ty)
347 -- Check out the comment on RnIfaces.getNonWiredDataDecl about ccalls
348 = lookupOrigNames [cCallableClass_RDR,
349 cReturnableClass_RDR,
350 ioDataCon_RDR] `thenRn` \ implicit_fvs ->
351 rnExprs args `thenRn` \ (args', fvs_args) ->
352 returnRn (HsCCall fun args' may_gc is_casm fake_result_ty,
353 fvs_args `plusFV` implicit_fvs)
355 rnExpr (HsSCC lbl expr)
356 = rnExpr expr `thenRn` \ (expr', fvs_expr) ->
357 returnRn (HsSCC lbl expr', fvs_expr)
359 rnExpr (HsCase expr ms src_loc)
360 = pushSrcLocRn src_loc $
361 rnExpr expr `thenRn` \ (new_expr, e_fvs) ->
362 mapFvRn rnMatch ms `thenRn` \ (new_ms, ms_fvs) ->
363 returnRn (HsCase new_expr new_ms src_loc, e_fvs `plusFV` ms_fvs)
365 rnExpr (HsLet binds expr)
366 = rnBinds binds $ \ binds' ->
367 rnExpr expr `thenRn` \ (expr',fvExpr) ->
368 returnRn (HsLet binds' expr', fvExpr)
370 rnExpr (HsWith expr binds)
371 = rnExpr expr `thenRn` \ (expr',fvExpr) ->
372 rnIPBinds binds `thenRn` \ (binds',fvBinds) ->
373 returnRn (HsWith expr' binds', fvExpr `plusFV` fvBinds)
375 rnExpr e@(HsDo do_or_lc stmts src_loc)
376 = pushSrcLocRn src_loc $
377 lookupOrigNames implicit_rdr_names `thenRn` \ implicit_fvs ->
378 rnStmts rnExpr stmts `thenRn` \ ((_, stmts'), fvs) ->
379 -- check the statement list ends in an expression
380 case last stmts' of {
381 ExprStmt _ _ -> returnRn () ;
382 ReturnStmt _ -> returnRn () ; -- for list comprehensions
383 _ -> addErrRn (doStmtListErr e)
385 returnRn (HsDo do_or_lc stmts' src_loc, fvs `plusFV` implicit_fvs)
387 implicit_rdr_names = [foldr_RDR, build_RDR, monadClass_RDR]
388 -- Monad stuff should not be necessary for a list comprehension
389 -- but the typechecker looks up the bind and return Ids anyway
393 rnExpr (ExplicitList exps)
394 = rnExprs exps `thenRn` \ (exps', fvs) ->
395 returnRn (ExplicitList exps', fvs `addOneFV` listTyCon_name)
397 rnExpr (ExplicitTuple exps boxity)
398 = rnExprs exps `thenRn` \ (exps', fvs) ->
399 returnRn (ExplicitTuple exps' boxity, fvs `addOneFV` tycon_name)
401 tycon_name = tupleTyCon_name boxity (length exps)
403 rnExpr (RecordCon con_id rbinds)
404 = lookupOccRn con_id `thenRn` \ conname ->
405 rnRbinds "construction" rbinds `thenRn` \ (rbinds', fvRbinds) ->
406 returnRn (RecordCon conname rbinds', fvRbinds `addOneFV` conname)
408 rnExpr (RecordUpd expr rbinds)
409 = rnExpr expr `thenRn` \ (expr', fvExpr) ->
410 rnRbinds "update" rbinds `thenRn` \ (rbinds', fvRbinds) ->
411 returnRn (RecordUpd expr' rbinds', fvExpr `plusFV` fvRbinds)
413 rnExpr (ExprWithTySig expr pty)
414 = rnExpr expr `thenRn` \ (expr', fvExpr) ->
415 rnHsTypeFVs (text "an expression type signature") pty `thenRn` \ (pty', fvTy) ->
416 returnRn (ExprWithTySig expr' pty', fvExpr `plusFV` fvTy)
418 rnExpr (HsIf p b1 b2 src_loc)
419 = pushSrcLocRn src_loc $
420 rnExpr p `thenRn` \ (p', fvP) ->
421 rnExpr b1 `thenRn` \ (b1', fvB1) ->
422 rnExpr b2 `thenRn` \ (b2', fvB2) ->
423 returnRn (HsIf p' b1' b2' src_loc, plusFVs [fvP, fvB1, fvB2])
426 = rnHsTypeFVs doc a `thenRn` \ (t, fvT) ->
427 returnRn (HsType t, fvT)
429 doc = text "renaming a type pattern"
431 rnExpr (ArithSeqIn seq)
432 = lookupOrigName enumClass_RDR `thenRn` \ enum ->
433 rn_seq seq `thenRn` \ (new_seq, fvs) ->
434 returnRn (ArithSeqIn new_seq, fvs `addOneFV` enum)
437 = rnExpr expr `thenRn` \ (expr', fvExpr) ->
438 returnRn (From expr', fvExpr)
440 rn_seq (FromThen expr1 expr2)
441 = rnExpr expr1 `thenRn` \ (expr1', fvExpr1) ->
442 rnExpr expr2 `thenRn` \ (expr2', fvExpr2) ->
443 returnRn (FromThen expr1' expr2', fvExpr1 `plusFV` fvExpr2)
445 rn_seq (FromTo expr1 expr2)
446 = rnExpr expr1 `thenRn` \ (expr1', fvExpr1) ->
447 rnExpr expr2 `thenRn` \ (expr2', fvExpr2) ->
448 returnRn (FromTo expr1' expr2', fvExpr1 `plusFV` fvExpr2)
450 rn_seq (FromThenTo expr1 expr2 expr3)
451 = rnExpr expr1 `thenRn` \ (expr1', fvExpr1) ->
452 rnExpr expr2 `thenRn` \ (expr2', fvExpr2) ->
453 rnExpr expr3 `thenRn` \ (expr3', fvExpr3) ->
454 returnRn (FromThenTo expr1' expr2' expr3',
455 plusFVs [fvExpr1, fvExpr2, fvExpr3])
458 These three are pattern syntax appearing in expressions.
459 Since all the symbols are reservedops we can simply reject them.
460 We return a (bogus) EWildPat in each case.
463 rnExpr e@EWildPat = addErrRn (patSynErr e) `thenRn_`
464 returnRn (EWildPat, emptyFVs)
466 rnExpr e@(EAsPat _ _) = addErrRn (patSynErr e) `thenRn_`
467 returnRn (EWildPat, emptyFVs)
469 rnExpr e@(ELazyPat _) = addErrRn (patSynErr e) `thenRn_`
470 returnRn (EWildPat, emptyFVs)
475 %************************************************************************
477 \subsubsection{@Rbinds@s and @Rpats@s: in record expressions}
479 %************************************************************************
483 = mapRn_ field_dup_err dup_fields `thenRn_`
484 mapFvRn rn_rbind rbinds `thenRn` \ (rbinds', fvRbind) ->
485 returnRn (rbinds', fvRbind)
487 (_, dup_fields) = removeDups compare [ f | (f,_,_) <- rbinds ]
489 field_dup_err dups = addErrRn (dupFieldErr str dups)
491 rn_rbind (field, expr, pun)
492 = lookupGlobalOccRn field `thenRn` \ fieldname ->
493 rnExpr expr `thenRn` \ (expr', fvExpr) ->
494 returnRn ((fieldname, expr', pun), fvExpr `addOneFV` fieldname)
497 = mapRn_ field_dup_err dup_fields `thenRn_`
498 mapFvRn rn_rpat rpats `thenRn` \ (rpats', fvs) ->
499 returnRn (rpats', fvs)
501 (_, dup_fields) = removeDups compare [ f | (f,_,_) <- rpats ]
503 field_dup_err dups = addErrRn (dupFieldErr "pattern" dups)
505 rn_rpat (field, pat, pun)
506 = lookupGlobalOccRn field `thenRn` \ fieldname ->
507 rnPat pat `thenRn` \ (pat', fvs) ->
508 returnRn ((fieldname, pat', pun), fvs `addOneFV` fieldname)
511 %************************************************************************
513 \subsubsection{@rnIPBinds@s: in implicit parameter bindings} *
515 %************************************************************************
518 rnIPBinds [] = returnRn ([], emptyFVs)
519 rnIPBinds ((n, expr) : binds)
520 = newIPName n `thenRn` \ name ->
521 rnExpr expr `thenRn` \ (expr',fvExpr) ->
522 rnIPBinds binds `thenRn` \ (binds',fvBinds) ->
523 returnRn ((name, expr') : binds', fvExpr `plusFV` fvBinds)
527 %************************************************************************
529 \subsubsection{@Stmt@s: in @do@ expressions}
531 %************************************************************************
533 Note that although some bound vars may appear in the free var set for
534 the first qual, these will eventually be removed by the caller. For
535 example, if we have @[p | r <- s, q <- r, p <- q]@, when doing
536 @[q <- r, p <- q]@, the free var set for @q <- r@ will
537 be @{r}@, and the free var set for the entire Quals will be @{r}@. This
538 @r@ will be removed only when we finally return from examining all the
542 type RnExprTy = RdrNameHsExpr -> RnMS (RenamedHsExpr, FreeVars)
546 -> RnMS (([Name], [RenamedStmt]), FreeVars)
549 = returnRn (([], []), emptyFVs)
551 rnStmts rn_expr (stmt:stmts)
552 = getLocalNameEnv `thenRn` \ name_env ->
553 rnStmt rn_expr stmt $ \ stmt' ->
554 rnStmts rn_expr stmts `thenRn` \ ((binders, stmts'), fvs) ->
555 returnRn ((binders, stmt' : stmts'), fvs)
557 rnStmt :: RnExprTy -> RdrNameStmt
558 -> (RenamedStmt -> RnMS (([Name], a), FreeVars))
559 -> RnMS (([Name], a), FreeVars)
560 -- Because of mutual recursion we have to pass in rnExpr.
562 rnStmt rn_expr (ParStmt stmtss) thing_inside
563 = mapFvRn (rnStmts rn_expr) stmtss `thenRn` \ (bndrstmtss, fv_stmtss) ->
564 let binderss = map fst bndrstmtss
565 checkBndrs all_bndrs bndrs
566 = checkRn (null (intersectBy eqOcc all_bndrs bndrs)) err `thenRn_`
567 returnRn (bndrs ++ all_bndrs)
568 eqOcc n1 n2 = nameOccName n1 == nameOccName n2
569 err = text "duplicate binding in parallel list comprehension"
571 foldlRn checkBndrs [] binderss `thenRn` \ binders ->
572 bindLocalNamesFV binders $
573 thing_inside (ParStmtOut bndrstmtss)`thenRn` \ ((rest_bndrs, result), fv_rest) ->
574 returnRn ((rest_bndrs ++ binders, result), fv_stmtss `plusFV` fv_rest)
576 rnStmt rn_expr (BindStmt pat expr src_loc) thing_inside
577 = pushSrcLocRn src_loc $
578 rn_expr expr `thenRn` \ (expr', fv_expr) ->
579 bindLocalsFVRn doc binders $ \ new_binders ->
580 rnPat pat `thenRn` \ (pat', fv_pat) ->
581 thing_inside (BindStmt pat' expr' src_loc) `thenRn` \ ((rest_binders, result), fvs) ->
582 -- ZZ is shadowing handled correctly?
583 returnRn ((rest_binders ++ new_binders, result),
584 fv_expr `plusFV` fvs `plusFV` fv_pat)
586 binders = collectPatBinders pat
587 doc = text "a pattern in do binding"
589 rnStmt rn_expr (ExprStmt expr src_loc) thing_inside
590 = pushSrcLocRn src_loc $
591 rn_expr expr `thenRn` \ (expr', fv_expr) ->
592 thing_inside (ExprStmt expr' src_loc) `thenRn` \ (result, fvs) ->
593 returnRn (result, fv_expr `plusFV` fvs)
595 rnStmt rn_expr (GuardStmt expr src_loc) thing_inside
596 = pushSrcLocRn src_loc $
597 rn_expr expr `thenRn` \ (expr', fv_expr) ->
598 thing_inside (GuardStmt expr' src_loc) `thenRn` \ (result, fvs) ->
599 returnRn (result, fv_expr `plusFV` fvs)
601 rnStmt rn_expr (ReturnStmt expr) thing_inside
602 = rn_expr expr `thenRn` \ (expr', fv_expr) ->
603 thing_inside (ReturnStmt expr') `thenRn` \ (result, fvs) ->
604 returnRn (result, fv_expr `plusFV` fvs)
606 rnStmt rn_expr (LetStmt binds) thing_inside
607 = rnBinds binds $ \ binds' ->
608 thing_inside (LetStmt binds')
612 %************************************************************************
614 \subsubsection{Precedence Parsing}
616 %************************************************************************
618 @mkOpAppRn@ deals with operator fixities. The argument expressions
619 are assumed to be already correctly arranged. It needs the fixities
620 recorded in the OpApp nodes, because fixity info applies to the things
621 the programmer actually wrote, so you can't find it out from the Name.
623 Furthermore, the second argument is guaranteed not to be another
624 operator application. Why? Because the parser parses all
625 operator appications left-associatively, EXCEPT negation, which
626 we need to handle specially.
629 mkOpAppRn :: RenamedHsExpr -- Left operand; already rearranged
630 -> RenamedHsExpr -> Fixity -- Operator and fixity
631 -> RenamedHsExpr -- Right operand (not an OpApp, but might
633 -> RnMS RenamedHsExpr
635 ---------------------------
636 -- (e11 `op1` e12) `op2` e2
637 mkOpAppRn e1@(OpApp e11 op1 fix1 e12) op2 fix2 e2
639 = addErrRn (precParseErr (ppr_op op1,fix1) (ppr_op op2,fix2)) `thenRn_`
640 returnRn (OpApp e1 op2 fix2 e2)
643 = mkOpAppRn e12 op2 fix2 e2 `thenRn` \ new_e ->
644 returnRn (OpApp e11 op1 fix1 new_e)
646 (nofix_error, associate_right) = compareFixity fix1 fix2
648 ---------------------------
649 -- (- neg_arg) `op` e2
650 mkOpAppRn e1@(NegApp neg_arg) op2 fix2 e2
652 = addErrRn (precParseErr (pp_prefix_minus,negateFixity) (ppr_op op2,fix2)) `thenRn_`
653 returnRn (OpApp e1 op2 fix2 e2)
656 = mkOpAppRn neg_arg op2 fix2 e2 `thenRn` \ new_e ->
657 returnRn (NegApp new_e)
659 (nofix_error, associate_right) = compareFixity negateFixity fix2
661 ---------------------------
663 mkOpAppRn e1 op1 fix1 e2@(NegApp neg_arg) -- NegApp can occur on the right
664 | not associate_right -- We *want* right association
665 = addErrRn (precParseErr (ppr_op op1, fix1) (pp_prefix_minus, negateFixity)) `thenRn_`
666 returnRn (OpApp e1 op1 fix1 e2)
668 (_, associate_right) = compareFixity fix1 negateFixity
670 ---------------------------
672 mkOpAppRn e1 op fix e2 -- Default case, no rearrangment
673 = ASSERT2( right_op_ok fix e2,
674 ppr e1 $$ text "---" $$ ppr op $$ text "---" $$ ppr fix $$ text "---" $$ ppr e2
676 returnRn (OpApp e1 op fix e2)
678 -- Parser left-associates everything, but
679 -- derived instances may have correctly-associated things to
680 -- in the right operarand. So we just check that the right operand is OK
681 right_op_ok fix1 (OpApp _ _ fix2 _)
682 = not error_please && associate_right
684 (error_please, associate_right) = compareFixity fix1 fix2
685 right_op_ok fix1 other
688 -- Parser initially makes negation bind more tightly than any other operator
692 getModeRn `thenRn` \ mode ->
693 ASSERT( not_op_app mode neg_arg )
695 returnRn (NegApp neg_arg)
697 not_op_app SourceMode (OpApp _ _ _ _) = False
698 not_op_app mode other = True
702 mkConOpPatRn :: RenamedPat -> Name -> Fixity -> RenamedPat
705 mkConOpPatRn p1@(ConOpPatIn p11 op1 fix1 p12)
708 = addErrRn (precParseErr (ppr_op op1,fix1) (ppr_op op2,fix2)) `thenRn_`
709 returnRn (ConOpPatIn p1 op2 fix2 p2)
712 = mkConOpPatRn p12 op2 fix2 p2 `thenRn` \ new_p ->
713 returnRn (ConOpPatIn p11 op1 fix1 new_p)
716 (nofix_error, associate_right) = compareFixity fix1 fix2
718 mkConOpPatRn p1 op fix p2 -- Default case, no rearrangment
719 = ASSERT( not_op_pat p2 )
720 returnRn (ConOpPatIn p1 op fix p2)
722 not_op_pat (ConOpPatIn _ _ _ _) = False
723 not_op_pat other = True
727 checkPrecMatch :: Bool -> Name -> RenamedMatch -> RnMS ()
729 checkPrecMatch False fn match
732 checkPrecMatch True op (Match _ (p1:p2:_) _ _)
733 -- True indicates an infix lhs
734 = getModeRn `thenRn` \ mode ->
735 -- See comments with rnExpr (OpApp ...)
736 if isInterfaceMode mode
738 else checkPrec op p1 False `thenRn_`
741 checkPrecMatch True op _ = panic "checkPrecMatch"
743 checkPrec op (ConOpPatIn _ op1 _ _) right
744 = lookupFixityRn op `thenRn` \ op_fix@(Fixity op_prec op_dir) ->
745 lookupFixityRn op1 `thenRn` \ op1_fix@(Fixity op1_prec op1_dir) ->
747 inf_ok = op1_prec > op_prec ||
748 (op1_prec == op_prec &&
749 (op1_dir == InfixR && op_dir == InfixR && right ||
750 op1_dir == InfixL && op_dir == InfixL && not right))
752 info = (ppr_op op, op_fix)
753 info1 = (ppr_op op1, op1_fix)
754 (infol, infor) = if right then (info, info1) else (info1, info)
756 checkRn inf_ok (precParseErr infol infor)
758 checkPrec op pat right
761 -- Check precedence of (arg op) or (op arg) respectively
762 -- If arg is itself an operator application, its precedence should
763 -- be higher than that of op
764 checkSectionPrec left_or_right section op arg
766 OpApp _ op fix _ -> go_for_it (ppr_op op) fix
767 NegApp _ -> go_for_it pp_prefix_minus negateFixity
771 go_for_it pp_arg_op arg_fix@(Fixity arg_prec _)
772 = lookupFixityRn op_name `thenRn` \ op_fix@(Fixity op_prec _) ->
773 checkRn (op_prec < arg_prec)
774 (sectionPrecErr (ppr_op op_name, op_fix) (pp_arg_op, arg_fix) section)
781 @(compareFixity op1 op2)@ tells which way to arrange appication, or
782 whether there's an error.
785 compareFixity :: Fixity -> Fixity
786 -> (Bool, -- Error please
787 Bool) -- Associate to the right: a op1 (b op2 c)
788 compareFixity (Fixity prec1 dir1) (Fixity prec2 dir2)
789 = case prec1 `compare` prec2 of
792 EQ -> case (dir1, dir2) of
793 (InfixR, InfixR) -> right
794 (InfixL, InfixL) -> left
797 right = (False, True)
798 left = (False, False)
799 error_please = (True, False)
802 %************************************************************************
804 \subsubsection{Literals}
806 %************************************************************************
808 When literals occur we have to make sure
809 that the types and classes they involve
813 litFVs (HsChar c) = returnRn (unitFV charTyCon_name)
814 litFVs (HsCharPrim c) = returnRn (unitFV (getName charPrimTyCon))
815 litFVs (HsString s) = returnRn (mkFVs [listTyCon_name, charTyCon_name])
816 litFVs (HsStringPrim s) = returnRn (unitFV (getName addrPrimTyCon))
817 litFVs (HsInt i) = returnRn (unitFV (getName intTyCon))
818 litFVs (HsIntPrim i) = returnRn (unitFV (getName intPrimTyCon))
819 litFVs (HsFloatPrim f) = returnRn (unitFV (getName floatPrimTyCon))
820 litFVs (HsDoublePrim d) = returnRn (unitFV (getName doublePrimTyCon))
821 litFVs (HsLitLit l bogus_ty) = lookupOrigName cCallableClass_RDR `thenRn` \ cc ->
823 litFVs lit = pprPanic "RnExpr.litFVs" (ppr lit) -- HsInteger and HsRat only appear
824 -- in post-typechecker translations
826 rnOverLit (HsIntegral i)
828 = returnRn (HsIntegral i, unitFV fromIntName)
830 = lookupOrigNames [fromInteger_RDR, plusInteger_RDR, timesInteger_RDR] `thenRn` \ ns ->
831 -- Big integers are built, using + and *, out of small integers
832 returnRn (HsIntegral i, ns)
834 rnOverLit (HsFractional i)
835 = lookupOrigNames [fromRational_RDR, ratioDataCon_RDR,
836 plusInteger_RDR, timesInteger_RDR] `thenRn` \ ns ->
837 -- We have to make sure that the Ratio type is imported with
838 -- its constructor, because literals of type Ratio t are
839 -- built with that constructor.
840 -- The Rational type is needed too, but that will come in
841 -- when fractionalClass does.
842 -- The plus/times integer operations may be needed to construct the numerator
843 -- and denominator (see DsUtils.mkIntegerLit)
844 returnRn (HsFractional i, ns)
847 %************************************************************************
849 \subsubsection{Assertion utils}
851 %************************************************************************
854 mkAssertExpr :: RnMS (RenamedHsExpr, FreeVars)
856 lookupOrigName assertErr_RDR `thenRn` \ name ->
857 getSrcLocRn `thenRn` \ sloc ->
859 -- if we're ignoring asserts, return (\ _ e -> e)
860 -- if not, return (assertError "src-loc")
862 if opt_IgnoreAsserts then
863 getUniqRn `thenRn` \ uniq ->
865 vname = mkSysLocalName uniq SLIT("v")
866 expr = HsLam ignorePredMatch
867 loc = nameSrcLoc vname
868 ignorePredMatch = Match [] [WildPatIn, VarPatIn vname] Nothing
869 (GRHSs [GRHS [ExprStmt (HsVar vname) loc] loc]
872 returnRn (expr, unitFV name)
877 (HsLit (HsString (_PK_ (showSDoc (ppr sloc)))))
880 returnRn (expr, unitFV name)
884 %************************************************************************
886 \subsubsection{Errors}
888 %************************************************************************
891 ppr_op op = quotes (ppr op) -- Here, op can be a Name or a (Var n), where n is a Name
892 ppr_opfix (pp_op, fixity) = pp_op <+> brackets (ppr fixity)
893 pp_prefix_minus = ptext SLIT("prefix `-'")
895 dupFieldErr str (dup:rest)
896 = hsep [ptext SLIT("duplicate field name"),
898 ptext SLIT("in record"), text str]
901 = hang (ptext SLIT("precedence parsing error"))
902 4 (hsep [ptext SLIT("cannot mix"), ppr_opfix op1, ptext SLIT("and"),
904 ptext SLIT("in the same infix expression")])
906 sectionPrecErr op arg_op section
907 = vcat [ptext SLIT("The operator") <+> ppr_opfix op <+> ptext SLIT("of a section"),
908 nest 4 (ptext SLIT("must have lower precedence than the operand") <+> ppr_opfix arg_op),
909 nest 4 (ptext SLIT("In the section:") <+> quotes (ppr section))]
913 SLIT("accepting non-standard pattern guards (-fglasgow-exts to suppress this message)")
917 = (ptext SLIT("Illegal signature in pattern:") <+> ppr ty)
918 $$ nest 4 (ptext SLIT("Use -fglasgow-exts to permit it"))
921 = sep [ptext SLIT("Pattern syntax in expression context:"),
925 = sep [ptext SLIT("`do' statements must end in expression:"),