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,
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 TypeRep ( 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 <- doptM 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 <- doptM 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) }
204 rnLHsTypes :: SDoc -> [LHsType RdrName]
205 -> IOEnv (Env TcGblEnv TcLclEnv) [LHsType Name]
206 rnLHsTypes doc tys = mapM (rnLHsType doc) tys
211 rnForAll :: SDoc -> HsExplicitFlag -> [LHsTyVarBndr RdrName]
212 -> LHsContext RdrName -> LHsType RdrName -> RnM (HsType Name)
214 rnForAll doc _ [] (L _ []) (L _ ty) = rnHsType doc ty
215 -- One reason for this case is that a type like Int#
216 -- starts off as (HsForAllTy Nothing [] Int), in case
217 -- there is some quantification. Now that we have quantified
218 -- and discovered there are no type variables, it's nicer to turn
219 -- it into plain Int. If it were Int# instead of Int, we'd actually
220 -- get an error, because the body of a genuine for-all is
223 rnForAll doc exp forall_tyvars ctxt ty
224 = bindTyVarsRn forall_tyvars $ \ new_tyvars -> do
225 new_ctxt <- rnContext doc ctxt
226 new_ty <- rnLHsType doc ty
227 return (HsForAllTy exp new_tyvars new_ctxt new_ty)
228 -- Retain the same implicit/explicit flag as before
229 -- so that we can later print it correctly
231 rnConDeclFields :: SDoc -> [ConDeclField RdrName] -> RnM [ConDeclField Name]
232 rnConDeclFields doc fields = mapM (rnField doc) fields
234 rnField :: SDoc -> ConDeclField RdrName -> RnM (ConDeclField Name)
235 rnField doc (ConDeclField name ty haddock_doc)
236 = do { new_name <- lookupLocatedTopBndrRn name
237 ; new_ty <- rnLHsType doc ty
238 ; new_haddock_doc <- rnMbLHsDoc haddock_doc
239 ; return (ConDeclField new_name new_ty new_haddock_doc) }
242 %*********************************************************
244 \subsection{Contexts and predicates}
246 %*********************************************************
249 rnContext :: SDoc -> LHsContext RdrName -> RnM (LHsContext Name)
250 rnContext doc = wrapLocM (rnContext' doc)
252 rnContext' :: SDoc -> HsContext RdrName -> RnM (HsContext Name)
253 rnContext' doc ctxt = mapM (rnLPred doc) ctxt
255 rnLPred :: SDoc -> LHsPred RdrName -> RnM (LHsPred Name)
256 rnLPred doc = wrapLocM (rnPred doc)
258 rnPred :: SDoc -> HsPred RdrName
259 -> IOEnv (Env TcGblEnv TcLclEnv) (HsPred Name)
260 rnPred doc (HsClassP clas tys)
261 = do { clas_name <- lookupOccRn clas
262 ; tys' <- rnLHsTypes doc tys
263 ; return (HsClassP clas_name tys')
265 rnPred doc (HsEqualP ty1 ty2)
266 = do { ty1' <- rnLHsType doc ty1
267 ; ty2' <- rnLHsType doc ty2
268 ; return (HsEqualP ty1' ty2')
270 rnPred doc (HsIParam n ty)
271 = do { name <- newIPNameRn n
272 ; ty' <- rnLHsType doc ty
273 ; return (HsIParam name ty')
278 %************************************************************************
280 Fixities and precedence parsing
282 %************************************************************************
284 @mkOpAppRn@ deals with operator fixities. The argument expressions
285 are assumed to be already correctly arranged. It needs the fixities
286 recorded in the OpApp nodes, because fixity info applies to the things
287 the programmer actually wrote, so you can't find it out from the Name.
289 Furthermore, the second argument is guaranteed not to be another
290 operator application. Why? Because the parser parses all
291 operator appications left-associatively, EXCEPT negation, which
292 we need to handle specially.
293 Infix types are read in a *right-associative* way, so that
298 mkHsOpTyRn rearranges where necessary. The two arguments
299 have already been renamed and rearranged. It's made rather tiresome
300 by the presence of ->, which is a separate syntactic construct.
304 -- Building (ty1 `op1` (ty21 `op2` ty22))
305 mkHsOpTyRn :: (LHsType Name -> LHsType Name -> HsType Name)
306 -> Name -> Fixity -> LHsType Name -> LHsType Name
309 mkHsOpTyRn mk1 pp_op1 fix1 ty1 (L loc2 (HsOpTy ty21 op2 ty22))
310 = do { fix2 <- lookupTyFixityRn op2
311 ; mk_hs_op_ty mk1 pp_op1 fix1 ty1
312 (\t1 t2 -> HsOpTy t1 op2 t2)
313 (unLoc op2) fix2 ty21 ty22 loc2 }
315 mkHsOpTyRn mk1 pp_op1 fix1 ty1 (L loc2 (HsFunTy ty21 ty22))
316 = mk_hs_op_ty mk1 pp_op1 fix1 ty1
317 HsFunTy funTyConName funTyFixity ty21 ty22 loc2
319 mkHsOpTyRn mk1 _ _ ty1 ty2 -- Default case, no rearrangment
320 = return (mk1 ty1 ty2)
323 mk_hs_op_ty :: (LHsType Name -> LHsType Name -> HsType Name)
324 -> Name -> Fixity -> LHsType Name
325 -> (LHsType Name -> LHsType Name -> HsType Name)
326 -> Name -> Fixity -> LHsType Name -> LHsType Name -> SrcSpan
328 mk_hs_op_ty mk1 op1 fix1 ty1
329 mk2 op2 fix2 ty21 ty22 loc2
330 | nofix_error = do { precParseErr (op1,fix1) (op2,fix2)
331 ; return (mk1 ty1 (L loc2 (mk2 ty21 ty22))) }
332 | associate_right = return (mk1 ty1 (L loc2 (mk2 ty21 ty22)))
333 | otherwise = do { -- Rearrange to ((ty1 `op1` ty21) `op2` ty22)
334 new_ty <- mkHsOpTyRn mk1 op1 fix1 ty1 ty21
335 ; return (mk2 (noLoc new_ty) ty22) }
337 (nofix_error, associate_right) = compareFixity fix1 fix2
340 ---------------------------
341 mkOpAppRn :: LHsExpr Name -- Left operand; already rearranged
342 -> LHsExpr Name -> Fixity -- Operator and fixity
343 -> LHsExpr Name -- Right operand (not an OpApp, but might
347 -- (e11 `op1` e12) `op2` e2
348 mkOpAppRn e1@(L _ (OpApp e11 op1 fix1 e12)) op2 fix2 e2
350 = do precParseErr (get_op op1,fix1) (get_op op2,fix2)
351 return (OpApp e1 op2 fix2 e2)
353 | associate_right = do
354 new_e <- mkOpAppRn e12 op2 fix2 e2
355 return (OpApp e11 op1 fix1 (L loc' new_e))
357 loc'= combineLocs e12 e2
358 (nofix_error, associate_right) = compareFixity fix1 fix2
360 ---------------------------
361 -- (- neg_arg) `op` e2
362 mkOpAppRn e1@(L _ (NegApp neg_arg neg_name)) op2 fix2 e2
364 = do precParseErr (negateName,negateFixity) (get_op op2,fix2)
365 return (OpApp e1 op2 fix2 e2)
368 = do new_e <- mkOpAppRn neg_arg op2 fix2 e2
369 return (NegApp (L loc' new_e) neg_name)
371 loc' = combineLocs neg_arg e2
372 (nofix_error, associate_right) = compareFixity negateFixity fix2
374 ---------------------------
376 mkOpAppRn e1 op1 fix1 e2@(L _ (NegApp _ _)) -- NegApp can occur on the right
377 | not associate_right -- We *want* right association
378 = do precParseErr (get_op op1, fix1) (negateName, negateFixity)
379 return (OpApp e1 op1 fix1 e2)
381 (_, associate_right) = compareFixity fix1 negateFixity
383 ---------------------------
385 mkOpAppRn e1 op fix e2 -- Default case, no rearrangment
386 = ASSERT2( right_op_ok fix (unLoc e2),
387 ppr e1 $$ text "---" $$ ppr op $$ text "---" $$ ppr fix $$ text "---" $$ ppr e2
389 return (OpApp e1 op fix e2)
391 ----------------------------
392 get_op :: LHsExpr Name -> Name
393 get_op (L _ (HsVar n)) = n
394 get_op other = pprPanic "get_op" (ppr other)
396 -- Parser left-associates everything, but
397 -- derived instances may have correctly-associated things to
398 -- in the right operarand. So we just check that the right operand is OK
399 right_op_ok :: Fixity -> HsExpr Name -> Bool
400 right_op_ok fix1 (OpApp _ _ fix2 _)
401 = not error_please && associate_right
403 (error_please, associate_right) = compareFixity fix1 fix2
407 -- Parser initially makes negation bind more tightly than any other operator
408 -- And "deriving" code should respect this (use HsPar if not)
409 mkNegAppRn :: LHsExpr id -> SyntaxExpr id -> RnM (HsExpr id)
410 mkNegAppRn neg_arg neg_name
411 = ASSERT( not_op_app (unLoc neg_arg) )
412 return (NegApp neg_arg neg_name)
414 not_op_app :: HsExpr id -> Bool
415 not_op_app (OpApp _ _ _ _) = False
418 ---------------------------
419 mkOpFormRn :: LHsCmdTop Name -- Left operand; already rearranged
420 -> LHsExpr Name -> Fixity -- Operator and fixity
421 -> LHsCmdTop Name -- Right operand (not an infix)
424 -- (e11 `op1` e12) `op2` e2
425 mkOpFormRn a1@(L loc (HsCmdTop (L _ (HsArrForm op1 (Just fix1) [a11,a12])) _ _ _))
428 = do precParseErr (get_op op1,fix1) (get_op op2,fix2)
429 return (HsArrForm op2 (Just fix2) [a1, a2])
432 = do new_c <- mkOpFormRn a12 op2 fix2 a2
433 return (HsArrForm op1 (Just fix1)
434 [a11, L loc (HsCmdTop (L loc new_c) [] placeHolderType [])])
435 -- TODO: locs are wrong
437 (nofix_error, associate_right) = compareFixity fix1 fix2
440 mkOpFormRn arg1 op fix arg2 -- Default case, no rearrangment
441 = return (HsArrForm op (Just fix) [arg1, arg2])
444 --------------------------------------
445 mkConOpPatRn :: Located Name -> Fixity -> LPat Name -> LPat Name
448 mkConOpPatRn op2 fix2 p1@(L loc (ConPatIn op1 (InfixCon p11 p12))) p2
449 = do { fix1 <- lookupFixityRn (unLoc op1)
450 ; let (nofix_error, associate_right) = compareFixity fix1 fix2
452 ; if nofix_error then do
453 { precParseErr (unLoc op1,fix1) (unLoc op2,fix2)
454 ; return (ConPatIn op2 (InfixCon p1 p2)) }
456 else if associate_right then do
457 { new_p <- mkConOpPatRn op2 fix2 p12 p2
458 ; return (ConPatIn op1 (InfixCon p11 (L loc new_p))) } -- XXX loc right?
459 else return (ConPatIn op2 (InfixCon p1 p2)) }
461 mkConOpPatRn op _ p1 p2 -- Default case, no rearrangment
462 = ASSERT( not_op_pat (unLoc p2) )
463 return (ConPatIn op (InfixCon p1 p2))
465 not_op_pat :: Pat Name -> Bool
466 not_op_pat (ConPatIn _ (InfixCon _ _)) = False
469 --------------------------------------
470 checkPrecMatch :: Name -> MatchGroup Name -> RnM ()
471 -- Check precedence of a function binding written infix
472 -- eg a `op` b `C` c = ...
473 -- See comments with rnExpr (OpApp ...) about "deriving"
475 checkPrecMatch op (MatchGroup ms _)
478 check (L _ (Match (L l1 p1 : L l2 p2 :_) _ _))
479 = setSrcSpan (combineSrcSpans l1 l2) $
480 do checkPrec op p1 False
484 -- This can happen. Consider
487 -- The infix flag comes from the first binding of the group
488 -- but the second eqn has no args (an error, but not discovered
489 -- until the type checker). So we don't want to crash on the
492 checkPrec :: Name -> Pat Name -> Bool -> IOEnv (Env TcGblEnv TcLclEnv) ()
493 checkPrec op (ConPatIn op1 (InfixCon _ _)) right = do
494 op_fix@(Fixity op_prec op_dir) <- lookupFixityRn op
495 op1_fix@(Fixity op1_prec op1_dir) <- lookupFixityRn (unLoc op1)
497 inf_ok = op1_prec > op_prec ||
498 (op1_prec == op_prec &&
499 (op1_dir == InfixR && op_dir == InfixR && right ||
500 op1_dir == InfixL && op_dir == InfixL && not right))
503 info1 = (unLoc op1, op1_fix)
504 (infol, infor) = if right then (info, info1) else (info1, info)
505 unless inf_ok (precParseErr infol infor)
510 -- Check precedence of (arg op) or (op arg) respectively
511 -- If arg is itself an operator application, then either
512 -- (a) its precedence must be higher than that of op
513 -- (b) its precedency & associativity must be the same as that of op
514 checkSectionPrec :: FixityDirection -> HsExpr RdrName
515 -> LHsExpr Name -> LHsExpr Name -> RnM ()
516 checkSectionPrec direction section op arg
518 OpApp _ op fix _ -> go_for_it (get_op op) fix
519 NegApp _ _ -> go_for_it negateName negateFixity
523 go_for_it arg_op arg_fix@(Fixity arg_prec assoc) = do
524 op_fix@(Fixity op_prec _) <- lookupFixityRn op_name
525 unless (op_prec < arg_prec
526 || (op_prec == arg_prec && direction == assoc))
527 (sectionPrecErr (op_name, op_fix)
528 (arg_op, arg_fix) section)
531 Precedence-related error messages
534 precParseErr :: (Name, Fixity) -> (Name, Fixity) -> RnM ()
535 precParseErr op1@(n1,_) op2@(n2,_)
536 | isUnboundName n1 || isUnboundName n2
537 = return () -- Avoid error cascade
539 = addErr $ hang (ptext (sLit "Precedence parsing error"))
540 4 (hsep [ptext (sLit "cannot mix"), ppr_opfix op1, ptext (sLit "and"),
542 ptext (sLit "in the same infix expression")])
544 sectionPrecErr :: (Name, Fixity) -> (Name, Fixity) -> HsExpr RdrName -> RnM ()
545 sectionPrecErr op@(n1,_) arg_op@(n2,_) section
546 | isUnboundName n1 || isUnboundName n2
547 = return () -- Avoid error cascade
549 = addErr $ vcat [ptext (sLit "The operator") <+> ppr_opfix op <+> ptext (sLit "of a section"),
550 nest 4 (sep [ptext (sLit "must have lower precedence than that of the operand,"),
551 nest 2 (ptext (sLit "namely") <+> ppr_opfix arg_op)]),
552 nest 4 (ptext (sLit "in the section:") <+> quotes (ppr section))]
554 ppr_opfix :: (Name, Fixity) -> SDoc
555 ppr_opfix (op, fixity) = pp_op <+> brackets (ppr fixity)
557 pp_op | op == negateName = ptext (sLit "prefix `-'")
558 | otherwise = quotes (ppr op)
561 %*********************************************************
565 %*********************************************************
568 forAllWarn :: SDoc -> LHsType RdrName -> Located RdrName
569 -> TcRnIf TcGblEnv TcLclEnv ()
570 forAllWarn doc ty (L loc tyvar)
571 = ifOptM Opt_WarnUnusedMatches $
572 addWarnAt loc (sep [ptext (sLit "The universally quantified type variable") <+> quotes (ppr tyvar),
573 nest 4 (ptext (sLit "does not appear in the type") <+> quotes (ppr ty))]
577 opTyErr :: RdrName -> HsType RdrName -> SDoc
578 opTyErr op ty@(HsOpTy ty1 _ _)
579 = hang (ptext (sLit "Illegal operator") <+> quotes (ppr op) <+> ptext (sLit "in type") <+> quotes (ppr ty))
582 extra | op == dot_tv_RDR && forall_head ty1
585 = ptext (sLit "Use -XTypeOperators to allow operators in types")
587 forall_head (L _ (HsTyVar tv)) = tv == forall_tv_RDR
588 forall_head (L _ (HsAppTy ty _)) = forall_head ty
589 forall_head _other = False
590 opTyErr _ ty = pprPanic "opTyErr: Not an op" (ppr ty)
593 %*********************************************************
597 %*********************************************************
603 h = ...$(thing "f")...
605 The splice can expand into literally anything, so when we do dependency
606 analysis we must assume that it might mention 'f'. So we simply treat
607 all locally-defined names as mentioned by any splice. This is terribly
608 brutal, but I don't see what else to do. For example, it'll mean
609 that every locally-defined thing will appear to be used, so no unused-binding
610 warnings. But if we miss the dependency, then we might typecheck 'h' before 'f',
611 and that will crash the type checker because 'f' isn't in scope.
613 Currently, I'm not treating a splice as also mentioning every import,
614 which is a bit inconsistent -- but there are a lot of them. We might
615 thereby get some bogus unused-import warnings, but we won't crash the
616 type checker. Not very satisfactory really.
619 rnSplice :: HsSplice RdrName -> RnM (HsSplice Name, FreeVars)
620 rnSplice (HsSplice n expr)
621 = do { checkTH expr "splice"
623 ; n' <- newLocalBndrRn (L loc n)
624 ; (expr', fvs) <- rnLExpr expr
626 -- Ugh! See Note [Splices] above
627 ; lcl_rdr <- getLocalRdrEnv
628 ; gbl_rdr <- getGlobalRdrEnv
629 ; let gbl_names = mkNameSet [gre_name gre | gre <- globalRdrEnvElts gbl_rdr,
631 lcl_names = mkNameSet (occEnvElts lcl_rdr)
633 ; return (HsSplice n' expr', fvs `plusFV` lcl_names `plusFV` gbl_names) }
635 checkTH :: Outputable a => a -> String -> RnM ()
637 checkTH _ _ = return () -- OK
639 checkTH e what -- Raise an error in a stage-1 compiler
640 = addErr (vcat [ptext (sLit "Template Haskell") <+> text what <+>
641 ptext (sLit "illegal in a stage-1 compiler"),