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, rnConDeclFields, rnLPred,
12 -- Precence related stuff
13 mkOpAppRn, mkNegAppRn, mkOpFormRn, mkConOpPatRn,
14 checkPrecMatch, checkSectionPrec,
16 -- Splice related stuff
20 import {-# SOURCE #-} RnExpr( rnLExpr )
22 import {-# SOURCE #-} TcSplice( runQuasiQuoteType )
27 import RdrHsSyn ( extractHsRhoRdrTyVars )
28 import RnHsSyn ( extractHsTyNames )
29 import RnHsDoc ( rnLHsDoc, rnMbLHsDoc )
34 import TysPrim ( funTyConName )
39 import BasicTypes ( compareFixity, funTyFixity, negateFixity,
40 Fixity(..), FixityDirection(..) )
43 import Control.Monad ( unless )
45 #include "HsVersions.h"
48 These type renamers are in a separate module, rather than in (say) RnSource,
49 to break several loop.
51 %*********************************************************
53 \subsection{Renaming types}
55 %*********************************************************
58 rnHsTypeFVs :: SDoc -> LHsType RdrName -> RnM (LHsType Name, FreeVars)
59 rnHsTypeFVs doc_str ty = do
60 ty' <- rnLHsType doc_str ty
61 return (ty', extractHsTyNames ty')
63 rnHsSigType :: SDoc -> LHsType RdrName -> RnM (LHsType Name)
64 -- rnHsSigType is used for source-language type signatures,
65 -- which use *implicit* universal quantification.
66 rnHsSigType doc_str ty
67 = rnLHsType (text "In the type signature for" <+> doc_str) ty
70 rnHsType is here because we call it from loadInstDecl, and I didn't
71 want a gratuitous knot.
74 rnLHsType :: SDoc -> LHsType RdrName -> RnM (LHsType Name)
75 rnLHsType doc = wrapLocM (rnHsType doc)
77 rnHsType :: SDoc -> HsType RdrName -> RnM (HsType Name)
79 rnHsType doc (HsForAllTy Implicit _ ctxt ty) = do
80 -- Implicit quantifiction in source code (no kinds on tyvars)
81 -- Given the signature C => T we universally quantify
82 -- over FV(T) \ {in-scope-tyvars}
83 name_env <- getLocalRdrEnv
85 mentioned = extractHsRhoRdrTyVars ctxt ty
87 -- Don't quantify over type variables that are in scope;
88 -- when GlasgowExts is off, there usually won't be any, except for
90 -- class C a where { op :: a -> a }
91 forall_tyvars = filter (not . (`elemLocalRdrEnv` name_env) . unLoc) mentioned
92 tyvar_bndrs = userHsTyVarBndrs forall_tyvars
94 rnForAll doc Implicit tyvar_bndrs ctxt ty
96 rnHsType doc (HsForAllTy Explicit forall_tyvars ctxt tau) = do
97 -- Explicit quantification.
98 -- Check that the forall'd tyvars are actually
99 -- mentioned in the type, and produce a warning if not
101 mentioned = map unLoc (extractHsRhoRdrTyVars ctxt tau)
102 forall_tyvar_names = hsLTyVarLocNames forall_tyvars
104 -- Explicitly quantified but not mentioned in ctxt or tau
105 warn_guys = filter ((`notElem` mentioned) . unLoc) forall_tyvar_names
107 mapM_ (forAllWarn doc tau) warn_guys
108 rnForAll doc Explicit forall_tyvars ctxt tau
110 rnHsType _ (HsTyVar tyvar) = do
111 tyvar' <- lookupOccRn tyvar
112 return (HsTyVar tyvar')
114 -- If we see (forall a . ty), without foralls on, the forall will give
115 -- a sensible error message, but we don't want to complain about the dot too
116 -- Hence the jiggery pokery with ty1
117 rnHsType doc ty@(HsOpTy ty1 (L loc op) ty2)
119 do { ops_ok <- xoptM Opt_TypeOperators
122 else do { addErr (opTyErr op ty)
123 ; return (mkUnboundName op) } -- Avoid double complaint
124 ; let l_op' = L loc op'
125 ; fix <- lookupTyFixityRn l_op'
126 ; ty1' <- rnLHsType doc ty1
127 ; ty2' <- rnLHsType doc ty2
128 ; mkHsOpTyRn (\t1 t2 -> HsOpTy t1 l_op' t2) op' fix ty1' ty2' }
130 rnHsType doc (HsParTy ty) = do
131 ty' <- rnLHsType doc ty
134 rnHsType doc (HsBangTy b ty)
135 = do { ty' <- rnLHsType doc ty
136 ; return (HsBangTy b ty') }
138 rnHsType doc (HsRecTy flds)
139 = do { flds' <- rnConDeclFields doc flds
140 ; return (HsRecTy flds') }
142 rnHsType _ (HsNumTy i)
143 | i == 1 = return (HsNumTy i)
144 | otherwise = addErr err_msg >> return (HsNumTy i)
146 err_msg = ptext (sLit "Only unit numeric type pattern is valid")
149 rnHsType doc (HsFunTy ty1 ty2) = do
150 ty1' <- rnLHsType doc ty1
151 -- Might find a for-all as the arg of a function type
152 ty2' <- rnLHsType doc ty2
153 -- Or as the result. This happens when reading Prelude.hi
154 -- when we find return :: forall m. Monad m -> forall a. a -> m a
156 -- Check for fixity rearrangements
157 mkHsOpTyRn HsFunTy funTyConName funTyFixity ty1' ty2'
159 rnHsType doc (HsListTy ty) = do
160 ty' <- rnLHsType doc ty
161 return (HsListTy ty')
163 rnHsType doc (HsKindSig ty k)
164 = do { kind_sigs_ok <- xoptM Opt_KindSignatures
165 ; unless kind_sigs_ok (addErr (kindSigErr ty))
166 ; ty' <- rnLHsType doc ty
167 ; return (HsKindSig ty' k) }
169 rnHsType doc (HsPArrTy ty) = do
170 ty' <- rnLHsType doc ty
171 return (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) = do
176 tys' <- mapM (rnLHsType doc) tys
177 return (HsTupleTy tup_con tys')
179 rnHsType doc (HsAppTy ty1 ty2) = do
180 ty1' <- rnLHsType doc ty1
181 ty2' <- rnLHsType doc ty2
182 return (HsAppTy ty1' ty2')
184 rnHsType doc (HsPredTy pred) = do
185 pred' <- rnPred doc pred
186 return (HsPredTy pred')
188 rnHsType _ (HsSpliceTy sp _ k)
189 = do { (sp', fvs) <- rnSplice sp -- ToDo: deal with fvs
190 ; return (HsSpliceTy sp' fvs k) }
192 rnHsType doc (HsDocTy ty haddock_doc) = do
193 ty' <- rnLHsType doc ty
194 haddock_doc' <- rnLHsDoc haddock_doc
195 return (HsDocTy ty' haddock_doc')
198 rnHsType _ ty@(HsQuasiQuoteTy _) = pprPanic "Can't do quasiquotation without GHCi" (ppr ty)
200 rnHsType doc (HsQuasiQuoteTy qq) = do { ty <- runQuasiQuoteType qq
201 ; rnHsType doc (unLoc ty) }
203 rnHsType _ (HsCoreTy ty) = return (HsCoreTy ty)
206 rnLHsTypes :: SDoc -> [LHsType RdrName]
207 -> IOEnv (Env TcGblEnv TcLclEnv) [LHsType Name]
208 rnLHsTypes doc tys = mapM (rnLHsType doc) tys
213 rnForAll :: SDoc -> HsExplicitFlag -> [LHsTyVarBndr RdrName]
214 -> LHsContext RdrName -> LHsType RdrName -> RnM (HsType Name)
216 rnForAll doc _ [] (L _ []) (L _ ty) = rnHsType doc ty
217 -- One reason for this case is that a type like Int#
218 -- starts off as (HsForAllTy Nothing [] Int), in case
219 -- there is some quantification. Now that we have quantified
220 -- and discovered there are no type variables, it's nicer to turn
221 -- it into plain Int. If it were Int# instead of Int, we'd actually
222 -- get an error, because the body of a genuine for-all is
225 rnForAll doc exp forall_tyvars ctxt ty
226 = bindTyVarsRn forall_tyvars $ \ new_tyvars -> do
227 new_ctxt <- rnContext doc ctxt
228 new_ty <- rnLHsType doc ty
229 return (HsForAllTy exp new_tyvars new_ctxt new_ty)
230 -- Retain the same implicit/explicit flag as before
231 -- so that we can later print it correctly
233 rnConDeclFields :: SDoc -> [ConDeclField RdrName] -> RnM [ConDeclField Name]
234 rnConDeclFields doc fields = mapM (rnField doc) fields
236 rnField :: SDoc -> ConDeclField RdrName -> RnM (ConDeclField Name)
237 rnField doc (ConDeclField name ty haddock_doc)
238 = do { new_name <- lookupLocatedTopBndrRn name
239 ; new_ty <- rnLHsType doc ty
240 ; new_haddock_doc <- rnMbLHsDoc haddock_doc
241 ; return (ConDeclField new_name new_ty new_haddock_doc) }
244 %*********************************************************
246 \subsection{Contexts and predicates}
248 %*********************************************************
251 rnContext :: SDoc -> LHsContext RdrName -> RnM (LHsContext Name)
252 rnContext doc = wrapLocM (rnContext' doc)
254 rnContext' :: SDoc -> HsContext RdrName -> RnM (HsContext Name)
255 rnContext' doc ctxt = mapM (rnLPred doc) ctxt
257 rnLPred :: SDoc -> LHsPred RdrName -> RnM (LHsPred Name)
258 rnLPred doc = wrapLocM (rnPred doc)
260 rnPred :: SDoc -> HsPred RdrName
261 -> IOEnv (Env TcGblEnv TcLclEnv) (HsPred Name)
262 rnPred doc (HsClassP clas tys)
263 = do { clas_name <- lookupOccRn clas
264 ; tys' <- rnLHsTypes doc tys
265 ; return (HsClassP clas_name tys')
267 rnPred doc (HsEqualP ty1 ty2)
268 = do { ty1' <- rnLHsType doc ty1
269 ; ty2' <- rnLHsType doc ty2
270 ; return (HsEqualP ty1' ty2')
272 rnPred doc (HsIParam n ty)
273 = do { name <- newIPNameRn n
274 ; ty' <- rnLHsType doc ty
275 ; return (HsIParam name ty')
280 %************************************************************************
282 Fixities and precedence parsing
284 %************************************************************************
286 @mkOpAppRn@ deals with operator fixities. The argument expressions
287 are assumed to be already correctly arranged. It needs the fixities
288 recorded in the OpApp nodes, because fixity info applies to the things
289 the programmer actually wrote, so you can't find it out from the Name.
291 Furthermore, the second argument is guaranteed not to be another
292 operator application. Why? Because the parser parses all
293 operator appications left-associatively, EXCEPT negation, which
294 we need to handle specially.
295 Infix types are read in a *right-associative* way, so that
300 mkHsOpTyRn rearranges where necessary. The two arguments
301 have already been renamed and rearranged. It's made rather tiresome
302 by the presence of ->, which is a separate syntactic construct.
306 -- Building (ty1 `op1` (ty21 `op2` ty22))
307 mkHsOpTyRn :: (LHsType Name -> LHsType Name -> HsType Name)
308 -> Name -> Fixity -> LHsType Name -> LHsType Name
311 mkHsOpTyRn mk1 pp_op1 fix1 ty1 (L loc2 (HsOpTy ty21 op2 ty22))
312 = do { fix2 <- lookupTyFixityRn op2
313 ; mk_hs_op_ty mk1 pp_op1 fix1 ty1
314 (\t1 t2 -> HsOpTy t1 op2 t2)
315 (unLoc op2) fix2 ty21 ty22 loc2 }
317 mkHsOpTyRn mk1 pp_op1 fix1 ty1 (L loc2 (HsFunTy ty21 ty22))
318 = mk_hs_op_ty mk1 pp_op1 fix1 ty1
319 HsFunTy funTyConName funTyFixity ty21 ty22 loc2
321 mkHsOpTyRn mk1 _ _ ty1 ty2 -- Default case, no rearrangment
322 = return (mk1 ty1 ty2)
325 mk_hs_op_ty :: (LHsType Name -> LHsType Name -> HsType Name)
326 -> Name -> Fixity -> LHsType Name
327 -> (LHsType Name -> LHsType Name -> HsType Name)
328 -> Name -> Fixity -> LHsType Name -> LHsType Name -> SrcSpan
330 mk_hs_op_ty mk1 op1 fix1 ty1
331 mk2 op2 fix2 ty21 ty22 loc2
332 | nofix_error = do { precParseErr (op1,fix1) (op2,fix2)
333 ; return (mk1 ty1 (L loc2 (mk2 ty21 ty22))) }
334 | associate_right = return (mk1 ty1 (L loc2 (mk2 ty21 ty22)))
335 | otherwise = do { -- Rearrange to ((ty1 `op1` ty21) `op2` ty22)
336 new_ty <- mkHsOpTyRn mk1 op1 fix1 ty1 ty21
337 ; return (mk2 (noLoc new_ty) ty22) }
339 (nofix_error, associate_right) = compareFixity fix1 fix2
342 ---------------------------
343 mkOpAppRn :: LHsExpr Name -- Left operand; already rearranged
344 -> LHsExpr Name -> Fixity -- Operator and fixity
345 -> LHsExpr Name -- Right operand (not an OpApp, but might
349 -- (e11 `op1` e12) `op2` e2
350 mkOpAppRn e1@(L _ (OpApp e11 op1 fix1 e12)) op2 fix2 e2
352 = do precParseErr (get_op op1,fix1) (get_op op2,fix2)
353 return (OpApp e1 op2 fix2 e2)
355 | associate_right = do
356 new_e <- mkOpAppRn e12 op2 fix2 e2
357 return (OpApp e11 op1 fix1 (L loc' new_e))
359 loc'= combineLocs e12 e2
360 (nofix_error, associate_right) = compareFixity fix1 fix2
362 ---------------------------
363 -- (- neg_arg) `op` e2
364 mkOpAppRn e1@(L _ (NegApp neg_arg neg_name)) op2 fix2 e2
366 = do precParseErr (negateName,negateFixity) (get_op op2,fix2)
367 return (OpApp e1 op2 fix2 e2)
370 = do new_e <- mkOpAppRn neg_arg op2 fix2 e2
371 return (NegApp (L loc' new_e) neg_name)
373 loc' = combineLocs neg_arg e2
374 (nofix_error, associate_right) = compareFixity negateFixity fix2
376 ---------------------------
378 mkOpAppRn e1 op1 fix1 e2@(L _ (NegApp _ _)) -- NegApp can occur on the right
379 | not associate_right -- We *want* right association
380 = do precParseErr (get_op op1, fix1) (negateName, negateFixity)
381 return (OpApp e1 op1 fix1 e2)
383 (_, associate_right) = compareFixity fix1 negateFixity
385 ---------------------------
387 mkOpAppRn e1 op fix e2 -- Default case, no rearrangment
388 = ASSERT2( right_op_ok fix (unLoc e2),
389 ppr e1 $$ text "---" $$ ppr op $$ text "---" $$ ppr fix $$ text "---" $$ ppr e2
391 return (OpApp e1 op fix e2)
393 ----------------------------
394 get_op :: LHsExpr Name -> Name
395 get_op (L _ (HsVar n)) = n
396 get_op other = pprPanic "get_op" (ppr other)
398 -- Parser left-associates everything, but
399 -- derived instances may have correctly-associated things to
400 -- in the right operarand. So we just check that the right operand is OK
401 right_op_ok :: Fixity -> HsExpr Name -> Bool
402 right_op_ok fix1 (OpApp _ _ fix2 _)
403 = not error_please && associate_right
405 (error_please, associate_right) = compareFixity fix1 fix2
409 -- Parser initially makes negation bind more tightly than any other operator
410 -- And "deriving" code should respect this (use HsPar if not)
411 mkNegAppRn :: LHsExpr id -> SyntaxExpr id -> RnM (HsExpr id)
412 mkNegAppRn neg_arg neg_name
413 = ASSERT( not_op_app (unLoc neg_arg) )
414 return (NegApp neg_arg neg_name)
416 not_op_app :: HsExpr id -> Bool
417 not_op_app (OpApp _ _ _ _) = False
420 ---------------------------
421 mkOpFormRn :: LHsCmdTop Name -- Left operand; already rearranged
422 -> LHsExpr Name -> Fixity -- Operator and fixity
423 -> LHsCmdTop Name -- Right operand (not an infix)
426 -- (e11 `op1` e12) `op2` e2
427 mkOpFormRn a1@(L loc (HsCmdTop (L _ (HsArrForm op1 (Just fix1) [a11,a12])) _ _ _))
430 = do precParseErr (get_op op1,fix1) (get_op op2,fix2)
431 return (HsArrForm op2 (Just fix2) [a1, a2])
434 = do new_c <- mkOpFormRn a12 op2 fix2 a2
435 return (HsArrForm op1 (Just fix1)
436 [a11, L loc (HsCmdTop (L loc new_c) [] placeHolderType [])])
437 -- TODO: locs are wrong
439 (nofix_error, associate_right) = compareFixity fix1 fix2
442 mkOpFormRn arg1 op fix arg2 -- Default case, no rearrangment
443 = return (HsArrForm op (Just fix) [arg1, arg2])
446 --------------------------------------
447 mkConOpPatRn :: Located Name -> Fixity -> LPat Name -> LPat Name
450 mkConOpPatRn op2 fix2 p1@(L loc (ConPatIn op1 (InfixCon p11 p12))) p2
451 = do { fix1 <- lookupFixityRn (unLoc op1)
452 ; let (nofix_error, associate_right) = compareFixity fix1 fix2
454 ; if nofix_error then do
455 { precParseErr (unLoc op1,fix1) (unLoc op2,fix2)
456 ; return (ConPatIn op2 (InfixCon p1 p2)) }
458 else if associate_right then do
459 { new_p <- mkConOpPatRn op2 fix2 p12 p2
460 ; return (ConPatIn op1 (InfixCon p11 (L loc new_p))) } -- XXX loc right?
461 else return (ConPatIn op2 (InfixCon p1 p2)) }
463 mkConOpPatRn op _ p1 p2 -- Default case, no rearrangment
464 = ASSERT( not_op_pat (unLoc p2) )
465 return (ConPatIn op (InfixCon p1 p2))
467 not_op_pat :: Pat Name -> Bool
468 not_op_pat (ConPatIn _ (InfixCon _ _)) = False
471 --------------------------------------
472 checkPrecMatch :: Name -> MatchGroup Name -> RnM ()
473 -- Check precedence of a function binding written infix
474 -- eg a `op` b `C` c = ...
475 -- See comments with rnExpr (OpApp ...) about "deriving"
477 checkPrecMatch op (MatchGroup ms _)
480 check (L _ (Match (L l1 p1 : L l2 p2 :_) _ _))
481 = setSrcSpan (combineSrcSpans l1 l2) $
482 do checkPrec op p1 False
486 -- This can happen. Consider
489 -- The infix flag comes from the first binding of the group
490 -- but the second eqn has no args (an error, but not discovered
491 -- until the type checker). So we don't want to crash on the
494 checkPrec :: Name -> Pat Name -> Bool -> IOEnv (Env TcGblEnv TcLclEnv) ()
495 checkPrec op (ConPatIn op1 (InfixCon _ _)) right = do
496 op_fix@(Fixity op_prec op_dir) <- lookupFixityRn op
497 op1_fix@(Fixity op1_prec op1_dir) <- lookupFixityRn (unLoc op1)
499 inf_ok = op1_prec > op_prec ||
500 (op1_prec == op_prec &&
501 (op1_dir == InfixR && op_dir == InfixR && right ||
502 op1_dir == InfixL && op_dir == InfixL && not right))
505 info1 = (unLoc op1, op1_fix)
506 (infol, infor) = if right then (info, info1) else (info1, info)
507 unless inf_ok (precParseErr infol infor)
512 -- Check precedence of (arg op) or (op arg) respectively
513 -- If arg is itself an operator application, then either
514 -- (a) its precedence must be higher than that of op
515 -- (b) its precedency & associativity must be the same as that of op
516 checkSectionPrec :: FixityDirection -> HsExpr RdrName
517 -> LHsExpr Name -> LHsExpr Name -> RnM ()
518 checkSectionPrec direction section op arg
520 OpApp _ op fix _ -> go_for_it (get_op op) fix
521 NegApp _ _ -> go_for_it negateName negateFixity
525 go_for_it arg_op arg_fix@(Fixity arg_prec assoc) = do
526 op_fix@(Fixity op_prec _) <- lookupFixityRn op_name
527 unless (op_prec < arg_prec
528 || (op_prec == arg_prec && direction == assoc))
529 (sectionPrecErr (op_name, op_fix)
530 (arg_op, arg_fix) section)
533 Precedence-related error messages
536 precParseErr :: (Name, Fixity) -> (Name, Fixity) -> RnM ()
537 precParseErr op1@(n1,_) op2@(n2,_)
538 | isUnboundName n1 || isUnboundName n2
539 = return () -- Avoid error cascade
541 = addErr $ hang (ptext (sLit "Precedence parsing error"))
542 4 (hsep [ptext (sLit "cannot mix"), ppr_opfix op1, ptext (sLit "and"),
544 ptext (sLit "in the same infix expression")])
546 sectionPrecErr :: (Name, Fixity) -> (Name, Fixity) -> HsExpr RdrName -> RnM ()
547 sectionPrecErr op@(n1,_) arg_op@(n2,_) section
548 | isUnboundName n1 || isUnboundName n2
549 = return () -- Avoid error cascade
551 = addErr $ vcat [ptext (sLit "The operator") <+> ppr_opfix op <+> ptext (sLit "of a section"),
552 nest 4 (sep [ptext (sLit "must have lower precedence than that of the operand,"),
553 nest 2 (ptext (sLit "namely") <+> ppr_opfix arg_op)]),
554 nest 4 (ptext (sLit "in the section:") <+> quotes (ppr section))]
556 ppr_opfix :: (Name, Fixity) -> SDoc
557 ppr_opfix (op, fixity) = pp_op <+> brackets (ppr fixity)
559 pp_op | op == negateName = ptext (sLit "prefix `-'")
560 | otherwise = quotes (ppr op)
563 %*********************************************************
567 %*********************************************************
570 forAllWarn :: SDoc -> LHsType RdrName -> Located RdrName
571 -> TcRnIf TcGblEnv TcLclEnv ()
572 forAllWarn doc ty (L loc tyvar)
573 = ifDOptM Opt_WarnUnusedMatches $
574 addWarnAt loc (sep [ptext (sLit "The universally quantified type variable") <+> quotes (ppr tyvar),
575 nest 4 (ptext (sLit "does not appear in the type") <+> quotes (ppr ty))]
579 opTyErr :: RdrName -> HsType RdrName -> SDoc
580 opTyErr op ty@(HsOpTy ty1 _ _)
581 = hang (ptext (sLit "Illegal operator") <+> quotes (ppr op) <+> ptext (sLit "in type") <+> quotes (ppr ty))
584 extra | op == dot_tv_RDR && forall_head ty1
587 = ptext (sLit "Use -XTypeOperators to allow operators in types")
589 forall_head (L _ (HsTyVar tv)) = tv == forall_tv_RDR
590 forall_head (L _ (HsAppTy ty _)) = forall_head ty
591 forall_head _other = False
592 opTyErr _ ty = pprPanic "opTyErr: Not an op" (ppr ty)
595 %*********************************************************
599 %*********************************************************
605 h = ...$(thing "f")...
607 The splice can expand into literally anything, so when we do dependency
608 analysis we must assume that it might mention 'f'. So we simply treat
609 all locally-defined names as mentioned by any splice. This is terribly
610 brutal, but I don't see what else to do. For example, it'll mean
611 that every locally-defined thing will appear to be used, so no unused-binding
612 warnings. But if we miss the dependency, then we might typecheck 'h' before 'f',
613 and that will crash the type checker because 'f' isn't in scope.
615 Currently, I'm not treating a splice as also mentioning every import,
616 which is a bit inconsistent -- but there are a lot of them. We might
617 thereby get some bogus unused-import warnings, but we won't crash the
618 type checker. Not very satisfactory really.
621 rnSplice :: HsSplice RdrName -> RnM (HsSplice Name, FreeVars)
622 rnSplice (HsSplice n expr)
623 = do { checkTH expr "splice"
625 ; n' <- newLocalBndrRn (L loc n)
626 ; (expr', fvs) <- rnLExpr expr
628 -- Ugh! See Note [Splices] above
629 ; lcl_rdr <- getLocalRdrEnv
630 ; gbl_rdr <- getGlobalRdrEnv
631 ; let gbl_names = mkNameSet [gre_name gre | gre <- globalRdrEnvElts gbl_rdr,
633 lcl_names = mkNameSet (occEnvElts lcl_rdr)
635 ; return (HsSplice n' expr', fvs `plusFV` lcl_names `plusFV` gbl_names) }
637 checkTH :: Outputable a => a -> String -> RnM ()
639 checkTH _ _ = return () -- OK
641 checkTH e what -- Raise an error in a stage-1 compiler
642 = addErr (vcat [ptext (sLit "Template Haskell") <+> text what <+>
643 ptext (sLit "illegal in a stage-1 compiler"),