2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[RnSource]{Main pass of renamer}
9 rnHsType, rnLHsType, rnLHsTypes, rnContext,
10 rnHsSigType, rnHsTypeFVs,
12 -- Patterns and literals
13 rnLPat, rnPat, rnPatsAndThen, -- Here because it's not part
14 rnLit, rnOverLit, -- of any mutual recursion
16 -- Precence related stuff
17 mkOpAppRn, mkNegAppRn, mkOpFormRn,
18 checkPrecMatch, checkSectionPrec,
21 dupFieldErr, patSigErr, checkTupSize
24 import DynFlags ( DynFlag(Opt_WarnUnusedMatches, Opt_GlasgowExts) )
27 import RdrHsSyn ( extractHsRhoRdrTyVars )
28 import RnHsSyn ( extractHsTyNames, parrTyCon_name, tupleTyCon_name,
31 import RnEnv ( lookupOccRn, lookupBndrRn, lookupSyntaxName,
32 lookupLocatedOccRn, lookupLocatedBndrRn,
33 lookupLocatedGlobalOccRn, bindTyVarsRn,
34 lookupFixityRn, lookupTyFixityRn,
35 mapFvRn, warnUnusedMatches,
36 newIPNameRn, bindPatSigTyVarsFV, bindLocatedLocalsFV )
38 import RdrName ( RdrName, elemLocalRdrEnv )
39 import PrelNames ( eqClassName, integralClassName, geName, eqName,
40 negateName, minusName, lengthPName, indexPName,
41 plusIntegerName, fromIntegerName, timesIntegerName,
42 ratioDataConName, fromRationalName )
43 import TypeRep ( funTyCon )
44 import Constants ( mAX_TUPLE_SIZE )
46 import SrcLoc ( SrcSpan, Located(..), unLoc, noLoc, combineLocs )
49 import Literal ( inIntRange, inCharRange )
50 import BasicTypes ( compareFixity, funTyFixity, negateFixity, compareFixity,
51 Fixity(..), FixityDirection(..) )
52 import ListSetOps ( removeDups )
55 #include "HsVersions.h"
58 These type renamers are in a separate module, rather than in (say) RnSource,
59 to break several loop.
61 %*********************************************************
63 \subsection{Renaming types}
65 %*********************************************************
68 rnHsTypeFVs :: SDoc -> LHsType RdrName -> RnM (LHsType Name, FreeVars)
69 rnHsTypeFVs doc_str ty
70 = rnLHsType doc_str ty `thenM` \ ty' ->
71 returnM (ty', extractHsTyNames ty')
73 rnHsSigType :: SDoc -> LHsType RdrName -> RnM (LHsType Name)
74 -- rnHsSigType is used for source-language type signatures,
75 -- which use *implicit* universal quantification.
76 rnHsSigType doc_str ty
77 = rnLHsType (text "In the type signature for" <+> doc_str) ty
80 rnHsType is here because we call it from loadInstDecl, and I didn't
81 want a gratuitous knot.
84 rnLHsType :: SDoc -> LHsType RdrName -> RnM (LHsType Name)
85 rnLHsType doc = wrapLocM (rnHsType doc)
87 rnHsType :: SDoc -> HsType RdrName -> RnM (HsType Name)
89 rnHsType doc (HsForAllTy Implicit _ ctxt ty)
90 -- Implicit quantifiction in source code (no kinds on tyvars)
91 -- Given the signature C => T we universally quantify
92 -- over FV(T) \ {in-scope-tyvars}
93 = getLocalRdrEnv `thenM` \ name_env ->
95 mentioned = extractHsRhoRdrTyVars ctxt ty
97 -- Don't quantify over type variables that are in scope;
98 -- when GlasgowExts is off, there usually won't be any, except for
100 -- class C a where { op :: a -> a }
101 forall_tyvars = filter (not . (`elemLocalRdrEnv` name_env) . unLoc) mentioned
102 tyvar_bndrs = userHsTyVarBndrs forall_tyvars
104 rnForAll doc Implicit tyvar_bndrs ctxt ty
106 rnHsType doc (HsForAllTy Explicit forall_tyvars ctxt tau)
107 -- Explicit quantification.
108 -- Check that the forall'd tyvars are actually
109 -- mentioned in the type, and produce a warning if not
111 mentioned = map unLoc (extractHsRhoRdrTyVars ctxt tau)
112 forall_tyvar_names = hsLTyVarLocNames forall_tyvars
114 -- Explicitly quantified but not mentioned in ctxt or tau
115 warn_guys = filter ((`notElem` mentioned) . unLoc) forall_tyvar_names
117 mappM_ (forAllWarn doc tau) warn_guys `thenM_`
118 rnForAll doc Explicit forall_tyvars ctxt tau
120 rnHsType doc (HsTyVar tyvar)
121 = lookupOccRn tyvar `thenM` \ tyvar' ->
122 returnM (HsTyVar tyvar')
124 rnHsType doc (HsOpTy ty1 (L loc op) ty2)
126 lookupOccRn op `thenM` \ op' ->
130 lookupTyFixityRn l_op' `thenM` \ fix ->
131 rnLHsType doc ty1 `thenM` \ ty1' ->
132 rnLHsType doc ty2 `thenM` \ ty2' ->
133 mkHsOpTyRn (\t1 t2 -> HsOpTy t1 l_op' t2) (ppr op') fix ty1' ty2'
136 rnHsType doc (HsParTy ty)
137 = rnLHsType doc ty `thenM` \ ty' ->
138 returnM (HsParTy ty')
140 rnHsType doc (HsBangTy b ty)
141 = rnLHsType doc ty `thenM` \ ty' ->
142 returnM (HsBangTy b ty')
144 rnHsType doc (HsNumTy i)
145 | i == 1 = returnM (HsNumTy i)
146 | otherwise = addErr err_msg `thenM_` returnM (HsNumTy i)
148 err_msg = ptext SLIT("Only unit numeric type pattern is valid")
151 rnHsType doc (HsFunTy ty1 ty2)
152 = rnLHsType doc ty1 `thenM` \ ty1' ->
153 -- Might find a for-all as the arg of a function type
154 rnLHsType doc ty2 `thenM` \ ty2' ->
155 -- Or as the result. This happens when reading Prelude.hi
156 -- when we find return :: forall m. Monad m -> forall a. a -> m a
158 -- Check for fixity rearrangements
159 mkHsOpTyRn HsFunTy (ppr funTyCon) funTyFixity ty1' ty2'
161 rnHsType doc (HsListTy ty)
162 = rnLHsType doc ty `thenM` \ ty' ->
163 returnM (HsListTy ty')
165 rnHsType doc (HsKindSig ty k)
166 = rnLHsType doc ty `thenM` \ ty' ->
167 returnM (HsKindSig ty' k)
169 rnHsType doc (HsPArrTy ty)
170 = rnLHsType doc ty `thenM` \ ty' ->
171 returnM (HsPArrTy ty')
173 -- Unboxed tuples are allowed to have poly-typed arguments. These
174 -- sometimes crop up as a result of CPR worker-wrappering dictionaries.
175 rnHsType doc (HsTupleTy tup_con tys)
176 = mappM (rnLHsType doc) tys `thenM` \ tys' ->
177 returnM (HsTupleTy tup_con tys')
179 rnHsType doc (HsAppTy ty1 ty2)
180 = rnLHsType doc ty1 `thenM` \ ty1' ->
181 rnLHsType doc ty2 `thenM` \ ty2' ->
182 returnM (HsAppTy ty1' ty2')
184 rnHsType doc (HsPredTy pred)
185 = rnPred doc pred `thenM` \ pred' ->
186 returnM (HsPredTy pred')
188 rnLHsTypes doc tys = mappM (rnLHsType doc) tys
193 rnForAll :: SDoc -> HsExplicitForAll -> [LHsTyVarBndr RdrName]
194 -> LHsContext RdrName -> LHsType RdrName -> RnM (HsType Name)
196 rnForAll doc exp [] (L _ []) (L _ ty) = rnHsType doc ty
197 -- One reason for this case is that a type like Int#
198 -- starts off as (HsForAllTy Nothing [] Int), in case
199 -- there is some quantification. Now that we have quantified
200 -- and discovered there are no type variables, it's nicer to turn
201 -- it into plain Int. If it were Int# instead of Int, we'd actually
202 -- get an error, because the body of a genuine for-all is
205 rnForAll doc exp forall_tyvars ctxt ty
206 = bindTyVarsRn doc forall_tyvars $ \ new_tyvars ->
207 rnContext doc ctxt `thenM` \ new_ctxt ->
208 rnLHsType doc ty `thenM` \ new_ty ->
209 returnM (HsForAllTy exp new_tyvars new_ctxt new_ty)
210 -- Retain the same implicit/explicit flag as before
211 -- so that we can later print it correctly
215 %************************************************************************
217 Fixities and precedence parsing
219 %************************************************************************
221 @mkOpAppRn@ deals with operator fixities. The argument expressions
222 are assumed to be already correctly arranged. It needs the fixities
223 recorded in the OpApp nodes, because fixity info applies to the things
224 the programmer actually wrote, so you can't find it out from the Name.
226 Furthermore, the second argument is guaranteed not to be another
227 operator application. Why? Because the parser parses all
228 operator appications left-associatively, EXCEPT negation, which
229 we need to handle specially.
230 Infix types are read in a *right-associative* way, so that
235 mkHsOpTyRn rearranges where necessary. The two arguments
236 have already been renamed and rearranged. It's made rather tiresome
237 by the presence of ->, which is a separate syntactic construct.
241 -- Building (ty1 `op1` (ty21 `op2` ty22))
242 mkHsOpTyRn :: (LHsType Name -> LHsType Name -> HsType Name)
243 -> SDoc -> Fixity -> LHsType Name -> LHsType Name
246 mkHsOpTyRn mk1 pp_op1 fix1 ty1 (L loc2 (HsOpTy ty21 op2 ty22))
247 = do { fix2 <- lookupTyFixityRn op2
248 ; mk_hs_op_ty mk1 pp_op1 fix1 ty1
249 (\t1 t2 -> HsOpTy t1 op2 t2)
250 (ppr op2) fix2 ty21 ty22 loc2 }
252 mkHsOpTyRn mk1 pp_op1 fix1 ty1 ty2@(L loc2 (HsFunTy ty21 ty22))
253 = mk_hs_op_ty mk1 pp_op1 fix1 ty1
254 HsFunTy (ppr funTyCon) funTyFixity ty21 ty22 loc2
256 mkHsOpTyRn mk1 pp_op1 fix1 ty1 ty2 -- Default case, no rearrangment
257 = return (mk1 ty1 ty2)
260 mk_hs_op_ty :: (LHsType Name -> LHsType Name -> HsType Name)
261 -> SDoc -> Fixity -> LHsType Name
262 -> (LHsType Name -> LHsType Name -> HsType Name)
263 -> SDoc -> Fixity -> LHsType Name -> LHsType Name -> SrcSpan
265 mk_hs_op_ty mk1 pp_op1 fix1 ty1
266 mk2 pp_op2 fix2 ty21 ty22 loc2
267 | nofix_error = do { addErr (precParseErr (quotes pp_op1,fix1)
268 (quotes pp_op2,fix2))
269 ; return (mk1 ty1 (L loc2 (mk2 ty21 ty22))) }
270 | associate_right = return (mk1 ty1 (L loc2 (mk2 ty21 ty22)))
271 | otherwise = do { -- Rearrange to ((ty1 `op1` ty21) `op2` ty22)
272 new_ty <- mkHsOpTyRn mk1 pp_op1 fix1 ty1 ty21
273 ; return (mk2 (noLoc new_ty) ty22) }
275 (nofix_error, associate_right) = compareFixity fix1 fix2
278 ---------------------------
279 mkOpAppRn :: LHsExpr Name -- Left operand; already rearranged
280 -> LHsExpr Name -> Fixity -- Operator and fixity
281 -> LHsExpr Name -- Right operand (not an OpApp, but might
285 -- (e11 `op1` e12) `op2` e2
286 mkOpAppRn e1@(L _ (OpApp e11 op1 fix1 e12)) op2 fix2 e2
288 = addErr (precParseErr (ppr_op op1,fix1) (ppr_op op2,fix2)) `thenM_`
289 returnM (OpApp e1 op2 fix2 e2)
292 = mkOpAppRn e12 op2 fix2 e2 `thenM` \ new_e ->
293 returnM (OpApp e11 op1 fix1 (L loc' new_e))
295 loc'= combineLocs e12 e2
296 (nofix_error, associate_right) = compareFixity fix1 fix2
298 ---------------------------
299 -- (- neg_arg) `op` e2
300 mkOpAppRn e1@(L _ (NegApp neg_arg neg_name)) op2 fix2 e2
302 = addErr (precParseErr (pp_prefix_minus,negateFixity) (ppr_op op2,fix2)) `thenM_`
303 returnM (OpApp e1 op2 fix2 e2)
306 = mkOpAppRn neg_arg op2 fix2 e2 `thenM` \ new_e ->
307 returnM (NegApp (L loc' new_e) neg_name)
309 loc' = combineLocs neg_arg e2
310 (nofix_error, associate_right) = compareFixity negateFixity fix2
312 ---------------------------
314 mkOpAppRn e1 op1 fix1 e2@(L _ (NegApp neg_arg _)) -- NegApp can occur on the right
315 | not associate_right -- We *want* right association
316 = addErr (precParseErr (ppr_op op1, fix1) (pp_prefix_minus, negateFixity)) `thenM_`
317 returnM (OpApp e1 op1 fix1 e2)
319 (_, associate_right) = compareFixity fix1 negateFixity
321 ---------------------------
323 mkOpAppRn e1 op fix e2 -- Default case, no rearrangment
324 = ASSERT2( right_op_ok fix (unLoc e2),
325 ppr e1 $$ text "---" $$ ppr op $$ text "---" $$ ppr fix $$ text "---" $$ ppr e2
327 returnM (OpApp e1 op fix e2)
329 -- Parser left-associates everything, but
330 -- derived instances may have correctly-associated things to
331 -- in the right operarand. So we just check that the right operand is OK
332 right_op_ok fix1 (OpApp _ _ fix2 _)
333 = not error_please && associate_right
335 (error_please, associate_right) = compareFixity fix1 fix2
336 right_op_ok fix1 other
339 -- Parser initially makes negation bind more tightly than any other operator
340 -- And "deriving" code should respect this (use HsPar if not)
341 mkNegAppRn :: LHsExpr id -> SyntaxExpr id -> RnM (HsExpr id)
342 mkNegAppRn neg_arg neg_name
343 = ASSERT( not_op_app (unLoc neg_arg) )
344 returnM (NegApp neg_arg neg_name)
346 not_op_app (OpApp _ _ _ _) = False
347 not_op_app other = True
349 ---------------------------
350 mkOpFormRn :: LHsCmdTop Name -- Left operand; already rearranged
351 -> LHsExpr Name -> Fixity -- Operator and fixity
352 -> LHsCmdTop Name -- Right operand (not an infix)
355 -- (e11 `op1` e12) `op2` e2
356 mkOpFormRn a1@(L loc (HsCmdTop (L _ (HsArrForm op1 (Just fix1) [a11,a12])) _ _ _))
359 = addErr (precParseErr (ppr_op op1,fix1) (ppr_op op2,fix2)) `thenM_`
360 returnM (HsArrForm op2 (Just fix2) [a1, a2])
363 = mkOpFormRn a12 op2 fix2 a2 `thenM` \ new_c ->
364 returnM (HsArrForm op1 (Just fix1)
365 [a11, L loc (HsCmdTop (L loc new_c) [] placeHolderType [])])
366 -- TODO: locs are wrong
368 (nofix_error, associate_right) = compareFixity fix1 fix2
371 mkOpFormRn arg1 op fix arg2 -- Default case, no rearrangment
372 = returnM (HsArrForm op (Just fix) [arg1, arg2])
375 --------------------------------------
376 mkConOpPatRn :: Located Name -> Fixity -> LPat Name -> LPat Name
379 mkConOpPatRn op2 fix2 p1@(L loc (ConPatIn op1 (InfixCon p11 p12))) p2
380 = lookupFixityRn (unLoc op1) `thenM` \ fix1 ->
382 (nofix_error, associate_right) = compareFixity fix1 fix2
385 addErr (precParseErr (ppr_op op1,fix1) (ppr_op op2,fix2)) `thenM_`
386 returnM (ConPatIn op2 (InfixCon p1 p2))
388 if associate_right then
389 mkConOpPatRn op2 fix2 p12 p2 `thenM` \ new_p ->
390 returnM (ConPatIn op1 (InfixCon p11 (L loc new_p))) -- XXX loc right?
392 returnM (ConPatIn op2 (InfixCon p1 p2))
394 mkConOpPatRn op fix p1 p2 -- Default case, no rearrangment
395 = ASSERT( not_op_pat (unLoc p2) )
396 returnM (ConPatIn op (InfixCon p1 p2))
398 not_op_pat (ConPatIn _ (InfixCon _ _)) = False
399 not_op_pat other = True
401 --------------------------------------
402 checkPrecMatch :: Bool -> Name -> MatchGroup Name -> RnM ()
403 -- True indicates an infix lhs
404 -- See comments with rnExpr (OpApp ...) about "deriving"
406 checkPrecMatch False fn match
408 checkPrecMatch True op (MatchGroup ms _)
411 check (L _ (Match (p1:p2:_) _ _))
412 = checkPrec op (unLoc p1) False `thenM_`
413 checkPrec op (unLoc p2) True
415 check _ = panic "checkPrecMatch"
417 checkPrec op (ConPatIn op1 (InfixCon _ _)) right
418 = lookupFixityRn op `thenM` \ op_fix@(Fixity op_prec op_dir) ->
419 lookupFixityRn (unLoc op1) `thenM` \ op1_fix@(Fixity op1_prec op1_dir) ->
421 inf_ok = op1_prec > op_prec ||
422 (op1_prec == op_prec &&
423 (op1_dir == InfixR && op_dir == InfixR && right ||
424 op1_dir == InfixL && op_dir == InfixL && not right))
426 info = (ppr_op op, op_fix)
427 info1 = (ppr_op op1, op1_fix)
428 (infol, infor) = if right then (info, info1) else (info1, info)
430 checkErr inf_ok (precParseErr infol infor)
432 checkPrec op pat right
435 -- Check precedence of (arg op) or (op arg) respectively
436 -- If arg is itself an operator application, then either
437 -- (a) its precedence must be higher than that of op
438 -- (b) its precedency & associativity must be the same as that of op
439 checkSectionPrec :: FixityDirection -> HsExpr RdrName
440 -> LHsExpr Name -> LHsExpr Name -> RnM ()
441 checkSectionPrec direction section op arg
443 OpApp _ op fix _ -> go_for_it (ppr_op op) fix
444 NegApp _ _ -> go_for_it pp_prefix_minus negateFixity
447 L _ (HsVar op_name) = op
448 go_for_it pp_arg_op arg_fix@(Fixity arg_prec assoc)
449 = lookupFixityRn op_name `thenM` \ op_fix@(Fixity op_prec _) ->
450 checkErr (op_prec < arg_prec
451 || op_prec == arg_prec && direction == assoc)
452 (sectionPrecErr (ppr_op op_name, op_fix)
453 (pp_arg_op, arg_fix) section)
456 Precedence-related error messages
460 = hang (ptext SLIT("precedence parsing error"))
461 4 (hsep [ptext SLIT("cannot mix"), ppr_opfix op1, ptext SLIT("and"),
463 ptext SLIT("in the same infix expression")])
465 sectionPrecErr op arg_op section
466 = vcat [ptext SLIT("The operator") <+> ppr_opfix op <+> ptext SLIT("of a section"),
467 nest 4 (ptext SLIT("must have lower precedence than the operand") <+> ppr_opfix arg_op),
468 nest 4 (ptext SLIT("in the section:") <+> quotes (ppr section))]
470 pp_prefix_minus = ptext SLIT("prefix `-'")
471 ppr_op op = quotes (ppr op) -- Here, op can be a Name or a (Var n), where n is a Name
472 ppr_opfix (pp_op, fixity) = pp_op <+> brackets (ppr fixity)
475 %*********************************************************
477 \subsection{Contexts and predicates}
479 %*********************************************************
482 rnContext :: SDoc -> LHsContext RdrName -> RnM (LHsContext Name)
483 rnContext doc = wrapLocM (rnContext' doc)
485 rnContext' :: SDoc -> HsContext RdrName -> RnM (HsContext Name)
486 rnContext' doc ctxt = mappM (rnLPred doc) ctxt
488 rnLPred :: SDoc -> LHsPred RdrName -> RnM (LHsPred Name)
489 rnLPred doc = wrapLocM (rnPred doc)
491 rnPred doc (HsClassP clas tys)
492 = lookupOccRn clas `thenM` \ clas_name ->
493 rnLHsTypes doc tys `thenM` \ tys' ->
494 returnM (HsClassP clas_name tys')
496 rnPred doc (HsIParam n ty)
497 = newIPNameRn n `thenM` \ name ->
498 rnLHsType doc ty `thenM` \ ty' ->
499 returnM (HsIParam name ty')
503 *********************************************************
505 \subsection{Patterns}
507 *********************************************************
510 rnPatsAndThen :: HsMatchContext Name
512 -> ([LPat Name] -> RnM (a, FreeVars))
514 -- Bring into scope all the binders and type variables
515 -- bound by the patterns; then rename the patterns; then
516 -- do the thing inside.
518 -- Note that we do a single bindLocalsRn for all the
519 -- matches together, so that we spot the repeated variable in
522 rnPatsAndThen ctxt pats thing_inside
523 = bindPatSigTyVarsFV pat_sig_tys $
524 bindLocatedLocalsFV doc_pat bndrs $ \ new_bndrs ->
525 rnLPats pats `thenM` \ (pats', pat_fvs) ->
526 thing_inside pats' `thenM` \ (res, res_fvs) ->
529 unused_binders = filter (not . (`elemNameSet` res_fvs)) new_bndrs
531 warnUnusedMatches unused_binders `thenM_`
532 returnM (res, res_fvs `plusFV` pat_fvs)
534 pat_sig_tys = collectSigTysFromPats pats
535 bndrs = collectLocatedPatsBinders pats
536 doc_pat = ptext SLIT("In") <+> pprMatchContext ctxt
538 rnLPats :: [LPat RdrName] -> RnM ([LPat Name], FreeVars)
539 rnLPats ps = mapFvRn rnLPat ps
541 rnLPat :: LPat RdrName -> RnM (LPat Name, FreeVars)
542 rnLPat = wrapLocFstM rnPat
544 -- -----------------------------------------------------------------------------
547 rnPat :: Pat RdrName -> RnM (Pat Name, FreeVars)
549 rnPat (WildPat _) = returnM (WildPat placeHolderType, emptyFVs)
552 = lookupBndrRn name `thenM` \ vname ->
553 returnM (VarPat vname, emptyFVs)
555 rnPat (SigPatIn pat ty)
556 = doptM Opt_GlasgowExts `thenM` \ glaExts ->
559 then rnLPat pat `thenM` \ (pat', fvs1) ->
560 rnHsTypeFVs doc ty `thenM` \ (ty', fvs2) ->
561 returnM (SigPatIn pat' ty', fvs1 `plusFV` fvs2)
563 else addErr (patSigErr ty) `thenM_`
564 rnPat (unLoc pat) -- XXX shouldn't throw away the loc
566 doc = text "In a pattern type-signature"
570 returnM (LitPat lit, emptyFVs)
572 rnPat (NPat lit mb_neg eq _)
573 = rnOverLit lit `thenM` \ (lit', fvs1) ->
575 Nothing -> returnM (Nothing, emptyFVs)
576 Just _ -> lookupSyntaxName negateName `thenM` \ (neg, fvs) ->
577 returnM (Just neg, fvs)
578 ) `thenM` \ (mb_neg', fvs2) ->
579 lookupSyntaxName eqName `thenM` \ (eq', fvs3) ->
580 returnM (NPat lit' mb_neg' eq' placeHolderType,
581 fvs1 `plusFV` fvs2 `plusFV` fvs3 `addOneFV` eqClassName)
582 -- Needed to find equality on pattern
584 rnPat (NPlusKPat name lit _ _)
585 = rnOverLit lit `thenM` \ (lit', fvs1) ->
586 lookupLocatedBndrRn name `thenM` \ name' ->
587 lookupSyntaxName minusName `thenM` \ (minus, fvs2) ->
588 lookupSyntaxName geName `thenM` \ (ge, fvs3) ->
589 returnM (NPlusKPat name' lit' ge minus,
590 fvs1 `plusFV` fvs2 `plusFV` fvs3 `addOneFV` integralClassName)
591 -- The Report says that n+k patterns must be in Integral
594 = rnLPat pat `thenM` \ (pat', fvs) ->
595 returnM (LazyPat pat', fvs)
597 rnPat (AsPat name pat)
598 = rnLPat pat `thenM` \ (pat', fvs) ->
599 lookupLocatedBndrRn name `thenM` \ vname ->
600 returnM (AsPat vname pat', fvs)
602 rnPat (ConPatIn con stuff) = rnConPat con stuff
606 = rnLPat pat `thenM` \ (pat', fvs) ->
607 returnM (ParPat pat', fvs)
609 rnPat (ListPat pats _)
610 = rnLPats pats `thenM` \ (patslist, fvs) ->
611 returnM (ListPat patslist placeHolderType, fvs `addOneFV` listTyCon_name)
613 rnPat (PArrPat pats _)
614 = rnLPats pats `thenM` \ (patslist, fvs) ->
615 returnM (PArrPat patslist placeHolderType,
616 fvs `plusFV` implicit_fvs `addOneFV` parrTyCon_name)
618 implicit_fvs = mkFVs [lengthPName, indexPName]
620 rnPat (TuplePat pats boxed)
621 = checkTupSize tup_size `thenM_`
622 rnLPats pats `thenM` \ (patslist, fvs) ->
623 returnM (TuplePat patslist boxed, fvs `addOneFV` tycon_name)
625 tup_size = length pats
626 tycon_name = tupleTyCon_name boxed tup_size
628 rnPat (TypePat name) =
629 rnHsTypeFVs (text "In a type pattern") name `thenM` \ (name', fvs) ->
630 returnM (TypePat name', fvs)
632 -- -----------------------------------------------------------------------------
635 rnConPat con (PrefixCon pats)
636 = lookupLocatedOccRn con `thenM` \ con' ->
637 rnLPats pats `thenM` \ (pats', fvs) ->
638 returnM (ConPatIn con' (PrefixCon pats'), fvs `addOneFV` unLoc con')
640 rnConPat con (RecCon rpats)
641 = lookupLocatedOccRn con `thenM` \ con' ->
642 rnRpats rpats `thenM` \ (rpats', fvs) ->
643 returnM (ConPatIn con' (RecCon rpats'), fvs `addOneFV` unLoc con')
645 rnConPat con (InfixCon pat1 pat2)
646 = lookupLocatedOccRn con `thenM` \ con' ->
647 rnLPat pat1 `thenM` \ (pat1', fvs1) ->
648 rnLPat pat2 `thenM` \ (pat2', fvs2) ->
649 lookupFixityRn (unLoc con') `thenM` \ fixity ->
650 mkConOpPatRn con' fixity pat1' pat2' `thenM` \ pat' ->
651 returnM (pat', fvs1 `plusFV` fvs2 `addOneFV` unLoc con')
653 -- -----------------------------------------------------------------------------
656 rnRpats :: [(Located RdrName, LPat RdrName)]
657 -> RnM ([(Located Name, LPat Name)], FreeVars)
659 = mappM_ field_dup_err dup_fields `thenM_`
660 mapFvRn rn_rpat rpats `thenM` \ (rpats', fvs) ->
661 returnM (rpats', fvs)
663 (_, dup_fields) = removeDups compare [ unLoc f | (f,_) <- rpats ]
665 field_dup_err dups = addErr (dupFieldErr "pattern" dups)
668 = lookupLocatedGlobalOccRn field `thenM` \ fieldname ->
669 rnLPat pat `thenM` \ (pat', fvs) ->
670 returnM ((fieldname, pat'), fvs `addOneFV` unLoc fieldname)
675 %************************************************************************
677 \subsubsection{Literals}
679 %************************************************************************
681 When literals occur we have to make sure
682 that the types and classes they involve
686 rnLit :: HsLit -> RnM ()
687 rnLit (HsChar c) = checkErr (inCharRange c) (bogusCharError c)
688 rnLit other = returnM ()
690 rnOverLit (HsIntegral i _)
691 = lookupSyntaxName fromIntegerName `thenM` \ (from_integer_name, fvs) ->
693 returnM (HsIntegral i from_integer_name, fvs)
695 extra_fvs = mkFVs [plusIntegerName, timesIntegerName]
696 -- Big integer literals are built, using + and *,
697 -- out of small integers (DsUtils.mkIntegerLit)
698 -- [NB: plusInteger, timesInteger aren't rebindable...
699 -- they are used to construct the argument to fromInteger,
700 -- which is the rebindable one.]
702 returnM (HsIntegral i from_integer_name, fvs `plusFV` extra_fvs)
704 rnOverLit (HsFractional i _)
705 = lookupSyntaxName fromRationalName `thenM` \ (from_rat_name, fvs) ->
707 extra_fvs = mkFVs [ratioDataConName, plusIntegerName, timesIntegerName]
708 -- We have to make sure that the Ratio type is imported with
709 -- its constructor, because literals of type Ratio t are
710 -- built with that constructor.
711 -- The Rational type is needed too, but that will come in
712 -- as part of the type for fromRational.
713 -- The plus/times integer operations may be needed to construct the numerator
714 -- and denominator (see DsUtils.mkIntegerLit)
716 returnM (HsFractional i from_rat_name, fvs `plusFV` extra_fvs)
721 %*********************************************************
725 %*********************************************************
728 checkTupSize :: Int -> RnM ()
729 checkTupSize tup_size
730 | tup_size <= mAX_TUPLE_SIZE
733 = addErr (sep [ptext SLIT("A") <+> int tup_size <> ptext SLIT("-tuple is too large for GHC"),
734 nest 2 (parens (ptext SLIT("max size is") <+> int mAX_TUPLE_SIZE)),
735 nest 2 (ptext SLIT("Workaround: use nested tuples or define a data type"))])
737 forAllWarn doc ty (L loc tyvar)
738 = ifOptM Opt_WarnUnusedMatches $
740 addWarn (sep [ptext SLIT("The universally quantified type variable") <+> quotes (ppr tyvar),
741 nest 4 (ptext SLIT("does not appear in the type") <+> quotes (ppr ty))]
747 = ptext SLIT("character literal out of range: '\\") <> char c <> char '\''
750 = (ptext SLIT("Illegal signature in pattern:") <+> ppr ty)
751 $$ nest 4 (ptext SLIT("Use -fglasgow-exts to permit it"))
754 = hsep [ptext SLIT("duplicate field name"),
756 ptext SLIT("in record"), text str]