RnSource.lhs 25.7 KB
Newer Older
1
%
2
% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
3 4 5 6
%
\section[RnSource]{Main pass of renamer}

\begin{code}
7
module RnSource ( 
8 9
	rnSrcDecls, addTcgDUs, 
	rnTyClDecls, checkModDeprec,
10
	rnSplice, checkTH
11
    ) where
12

13
#include "HsVersions.h"
sof's avatar
sof committed
14

15 16
import {-# SOURCE #-} RnExpr( rnLExpr )

17
import HsSyn
18 19
import RdrName		( RdrName, isRdrDataCon, elemLocalRdrEnv, globalRdrEnvElts,
			  GlobalRdrElt(..), isLocalGRE )
20
import RdrHsSyn		( extractGenericPatTyVars, extractHsRhoRdrTyVars )
21
import RnHsSyn
22
import RnTypes		( rnLHsType, rnLHsTypes, rnHsSigType, rnHsTypeFVs, rnContext )
23
import RnBinds		( rnTopBinds, rnMethodBinds, renameSigs, mkSigTvFn )
24
import RnEnv		( lookupLocalDataTcNames,
25
			  lookupLocatedTopBndrRn, lookupLocatedOccRn,
26
			  lookupOccRn, newLocalsRn, 
27
			  bindLocatedLocalsFV, bindPatSigTyVarsFV,
28
			  bindTyVarsRn, extendTyVarEnvFVRn,
29
			  bindLocalNames, checkDupNames, mapFvRn
30
			)
31
import TcRnMonad
32

33 34 35
import HscTypes		( FixityEnv, FixItem(..),
			  Deprecations, Deprecs(..), DeprecTxt, plusDeprecs )
import Class		( FunDep )
36
import Name		( Name, nameOccName )
37
import NameSet
38
import NameEnv
39
import OccName		( occEnvElts )
40
import Outputable
41
import SrcLoc		( Located(..), unLoc, noLoc )
42
import DynFlags	( DynFlag(..) )
43
import Maybes		( seqMaybe )
44
import Maybe            ( isNothing )
45
import BasicTypes       ( Boxity(..) )
46 47
\end{code}

48
@rnSourceDecl@ `renames' declarations.
49 50 51 52 53 54
It simultaneously performs dependency analysis and precedence parsing.
It also does the following error checks:
\begin{enumerate}
\item
Checks that tyvars are used properly. This includes checking
for undefined tyvars, and tyvars in contexts that are ambiguous.
55 56
(Some of this checking has now been moved to module @TcMonoType@,
since we don't have functional dependency information at this point.)
57 58 59
\item
Checks that all variable occurences are defined.
\item 
60
Checks the @(..)@ etc constraints in the export list.
61 62 63
\end{enumerate}


64
\begin{code}
65
rnSrcDecls :: HsGroup RdrName -> RnM (TcGblEnv, HsGroup Name)
66

67
rnSrcDecls (HsGroup { hs_valds  = val_decls,
68 69 70 71 72 73
		      hs_tyclds = tycl_decls,
		      hs_instds = inst_decls,
		      hs_fixds  = fix_decls,
		      hs_depds  = deprec_decls,
		      hs_fords  = foreign_decls,
		      hs_defds  = default_decls,
74
		      hs_ruleds = rule_decls })
75 76 77

 = do {		-- Deal with deprecations (returns only the extra deprecations)
	deprecs <- rnSrcDeprecDecls deprec_decls ;
78 79 80 81 82
	updGblEnv (\gbl -> gbl { tcg_deprecs = tcg_deprecs gbl `plusDeprecs` deprecs })
		  $ do {

		-- Deal with top-level fixity decls 
		-- (returns the total new fixity env)
83
        rn_fix_decls <- rnSrcFixityDecls fix_decls ;
84
	fix_env <- rnSrcFixityDeclsEnv rn_fix_decls ;
85 86 87
	updGblEnv (\gbl -> gbl { tcg_fix_env = fix_env })
		  $ do {

88
		-- Rename other declarations
89
	traceRn (text "Start rnmono") ;
90
	(rn_val_decls, bind_dus) <- rnTopBinds val_decls ;
91
	traceRn (text "finish rnmono" <+> ppr rn_val_decls) ;
92 93 94 95 96 97 98 99

		-- You might think that we could build proper def/use information
		-- for type and class declarations, but they can be involved
		-- in mutual recursion across modules, and we only do the SCC
		-- analysis for them in the type checker.
		-- So we content ourselves with gathering uses only; that
		-- means we'll only report a declaration as unused if it isn't
		-- mentioned at all.  Ah well.
100 101 102 103 104 105 106 107 108 109
	(rn_tycl_decls,    src_fvs1)
	   <- mapFvRn (wrapLocFstM rnTyClDecl) tycl_decls ;
	(rn_inst_decls,    src_fvs2)
	   <- mapFvRn (wrapLocFstM rnSrcInstDecl) inst_decls ;
	(rn_rule_decls,    src_fvs3)
	   <- mapFvRn (wrapLocFstM rnHsRuleDecl) rule_decls ;
	(rn_foreign_decls, src_fvs4)
	   <- mapFvRn (wrapLocFstM rnHsForeignDecl) foreign_decls ;
	(rn_default_decls, src_fvs5)
	   <- mapFvRn (wrapLocFstM rnDefaultDecl) default_decls ;
110 111 112 113 114
	
	let {
	   rn_group = HsGroup { hs_valds  = rn_val_decls,
			    	hs_tyclds = rn_tycl_decls,
			    	hs_instds = rn_inst_decls,
115
			    	hs_fixds  = rn_fix_decls,
116 117 118
			    	hs_depds  = [],
			    	hs_fords  = rn_foreign_decls,
			    	hs_defds  = rn_default_decls,
119
			    	hs_ruleds = rn_rule_decls } ;
120

121
	   other_fvs = plusFVs [src_fvs1, src_fvs2, src_fvs3, 
122
				src_fvs4, src_fvs5] ;
123
	   src_dus = bind_dus `plusDU` usesOnly other_fvs 
124 125 126 127
		-- Note: src_dus will contain *uses* for locally-defined types
		-- and classes, but no *defs* for them.  (Because rnTyClDecl 
		-- returns only the uses.)  This is a little 
		-- surprising but it doesn't actually matter at all.
128 129
	} ;

130
	traceRn (text "finish rnSrc" <+> ppr rn_group) ;
131
	traceRn (text "finish Dus" <+> ppr src_dus ) ;
132
	tcg_env <- getGblEnv ;
133
	return (tcg_env `addTcgDUs` src_dus, rn_group)
134
    }}}
135 136 137 138 139

rnTyClDecls :: [LTyClDecl RdrName] -> RnM [LTyClDecl Name]
rnTyClDecls tycl_decls = do 
  (decls', fvs) <- mapFvRn (wrapLocFstM rnTyClDecl) tycl_decls
  return decls'
140 141 142

addTcgDUs :: TcGblEnv -> DefUses -> TcGblEnv 
addTcgDUs tcg_env dus = tcg_env { tcg_dus = tcg_dus tcg_env `plusDU` dus }
143 144 145 146 147 148 149 150 151 152
\end{code}


%*********************************************************
%*						 	 *
	Source-code fixity declarations
%*							 *
%*********************************************************

\begin{code}
153
rnSrcFixityDecls :: [LFixitySig RdrName] -> RnM [LFixitySig Name]
154
rnSrcFixityDecls fix_decls
155 156 157 158 159
    = do fix_decls <- mapM rnFixityDecl fix_decls
         return (concat fix_decls)

rnFixityDecl :: LFixitySig RdrName -> RnM [LFixitySig Name]
rnFixityDecl (L loc (FixitySig (L nameLoc rdr_name) fixity))
160 161 162 163 164 165
    = setSrcSpan nameLoc $
        -- GHC extension: look up both the tycon and data con 
	-- for con-like things
	-- If neither are in scope, report an error; otherwise
	-- add both to the fixity env
      do names <- lookupLocalDataTcNames rdr_name
166 167 168
         return [ L loc (FixitySig (L nameLoc name) fixity)
                      | name <- names ]

169
rnSrcFixityDeclsEnv :: [LFixitySig Name] -> RnM FixityEnv
170
rnSrcFixityDeclsEnv fix_decls
171
  = getGblEnv					`thenM` \ gbl_env ->
172
    foldlM rnFixityDeclEnv (tcg_fix_env gbl_env) 
173 174
	    fix_decls				 	`thenM` \ fix_env ->
    traceRn (text "fixity env" <+> pprFixEnv fix_env)	`thenM_`
175 176
    returnM fix_env

177 178 179 180 181 182 183 184 185
rnFixityDeclEnv :: FixityEnv -> LFixitySig Name -> RnM FixityEnv
rnFixityDeclEnv fix_env (L loc (FixitySig (L nameLoc name) fixity))
  = case lookupNameEnv fix_env name of
      Just (FixItem _ _ loc') 
	  -> do addLocErr (L nameLoc name) (dupFixityDecl loc')
    	        return fix_env
      Nothing
          -> return (extendNameEnv fix_env name fix_item)
    where fix_item = FixItem (nameOccName name) fixity nameLoc
186 187 188 189 190

pprFixEnv :: FixityEnv -> SDoc
pprFixEnv env 
  = pprWithCommas (\ (FixItem n f _) -> ppr f <+> ppr n)
		  (nameEnvElts env)
191

192
dupFixityDecl loc rdr_name
193
  = vcat [ptext SLIT("Multiple fixity declarations for") <+> quotes (ppr rdr_name),
194 195
	  ptext SLIT("also at ") <+> ppr loc
	]
196 197 198 199 200 201 202 203 204 205 206 207 208 209
\end{code}


%*********************************************************
%*						 	 *
	Source-code deprecations declarations
%*							 *
%*********************************************************

For deprecations, all we do is check that the names are in scope.
It's only imported deprecations, dealt with in RnIfaces, that we
gather them together.

\begin{code}
210
rnSrcDeprecDecls :: [LDeprecDecl RdrName] -> RnM Deprecations
211 212 213 214
rnSrcDeprecDecls [] 
  = returnM NoDeprecs

rnSrcDeprecDecls decls
215 216
  = mappM (addLocM rn_deprec) decls	`thenM` \ pairs_s ->
    returnM (DeprecSome (mkNameEnv (concat pairs_s)))
217
 where
218
   rn_deprec (Deprecation rdr_name txt)
219 220
     = lookupLocalDataTcNames rdr_name	`thenM` \ names ->
       returnM [(name, (nameOccName name, txt)) | name <- names]
221 222 223 224

checkModDeprec :: Maybe DeprecTxt -> Deprecations
-- Check for a module deprecation; done once at top level
checkModDeprec Nothing    = NoDeprecs
225
checkModDeprec (Just txt) = DeprecAll txt
226
\end{code}
227

228 229 230 231 232
%*********************************************************
%*							*
\subsection{Source code declarations}
%*							*
%*********************************************************
233

234
\begin{code}
235 236 237
rnDefaultDecl (DefaultDecl tys)
  = mapFvRn (rnHsTypeFVs doc_str) tys	`thenM` \ (tys', fvs) ->
    returnM (DefaultDecl tys', fvs)
238
  where
239
    doc_str = text "In a `default' declaration"
240 241
\end{code}

242 243 244 245 246 247 248
%*********************************************************
%*							*
\subsection{Foreign declarations}
%*							*
%*********************************************************

\begin{code}
Simon Marlow's avatar
Simon Marlow committed
249
rnHsForeignDecl (ForeignImport name ty spec)
250
  = lookupLocatedTopBndrRn name	        `thenM` \ name' ->
251
    rnHsTypeFVs (fo_decl_msg name) ty	`thenM` \ (ty', fvs) ->
Simon Marlow's avatar
Simon Marlow committed
252
    returnM (ForeignImport name' ty' spec, fvs)
253

Simon Marlow's avatar
Simon Marlow committed
254
rnHsForeignDecl (ForeignExport name ty spec)
255
  = lookupLocatedOccRn name	        `thenM` \ name' ->
256
    rnHsTypeFVs (fo_decl_msg name) ty  	`thenM` \ (ty', fvs) ->
Simon Marlow's avatar
Simon Marlow committed
257
    returnM (ForeignExport name' ty' spec, fvs )
258 259 260
	-- NB: a foreign export is an *occurrence site* for name, so 
	--     we add it to the free-variable list.  It might, for example,
	--     be imported from another module
261

262
fo_decl_msg name = ptext SLIT("In the foreign declaration for") <+> ppr name
263 264 265 266 267 268 269 270 271 272
\end{code}


%*********************************************************
%*							*
\subsection{Instance declarations}
%*							*
%*********************************************************

\begin{code}
273
rnSrcInstDecl (InstDecl inst_ty mbinds uprags)
274
	-- Used for both source and interface file decls
275
  = rnHsSigType (text "an instance decl") inst_ty	`thenM` \ inst_ty' ->
276

277 278 279
	-- Rename the bindings
	-- The typechecker (not the renamer) checks that all 
	-- the bindings are for the right class
280
    let
281
	meth_doc    = text "In the bindings in an instance declaration"
282 283
	meth_names  = collectHsBindLocatedBinders mbinds
	(inst_tyvars, _, cls,_) = splitHsInstDeclTy (unLoc inst_ty')
284
    in
285
    checkDupNames meth_doc meth_names 	`thenM_`
286
    extendTyVarEnvForMethodBinds inst_tyvars (		
287 288
	-- (Slightly strangely) the forall-d tyvars scope over
	-- the method bindings too
289 290
	rnMethodBinds cls (\n->[]) 	-- No scoped tyvars
		      [] mbinds
291
    )						`thenM` \ (mbinds', meth_fvs) ->
292 293 294 295 296 297 298
	-- Rename the prags and signatures.
	-- Note that the type variables are not in scope here,
	-- so that	instance Eq a => Eq (T a) where
	--			{-# SPECIALISE instance Eq a => Eq (T [a]) #-}
	-- works OK. 
	--
	-- But the (unqualified) method names are in scope
299
    let 
300
	binders = collectHsBindBinders mbinds'
301
	ok_sig  = okInstDclSig (mkNameSet binders)
302
    in
303
    bindLocalNames binders (renameSigs ok_sig uprags)	`thenM` \ uprags' ->
304

305 306
    returnM (InstDecl inst_ty' mbinds' uprags',
	     meth_fvs `plusFV` hsSigsFVs uprags'
307
		      `plusFV` extractHsTyNames inst_ty')
308 309
\end{code}

310 311 312 313 314 315 316
For the method bindings in class and instance decls, we extend the 
type variable environment iff -fglasgow-exts

\begin{code}
extendTyVarEnvForMethodBinds tyvars thing_inside
  = doptM Opt_GlasgowExts			`thenM` \ opt_GlasgowExts ->
    if opt_GlasgowExts then
317
	extendTyVarEnvFVRn (map hsLTyVarName tyvars) thing_inside
318 319 320 321 322
    else
	thing_inside
\end{code}


323 324 325 326 327 328 329
%*********************************************************
%*							*
\subsection{Rules}
%*							*
%*********************************************************

\begin{code}
330
rnHsRuleDecl (HsRule rule_name act vars lhs fv_lhs rhs fv_rhs)
331
  = bindPatSigTyVarsFV (collectRuleBndrSigTys vars)	$
332

333
    bindLocatedLocalsFV doc (map get_var vars)		$ \ ids ->
334
    mapFvRn rn_var (vars `zip` ids)		`thenM` \ (vars', fv_vars) ->
335

336 337
    rnLExpr lhs					`thenM` \ (lhs', fv_lhs') ->
    rnLExpr rhs					`thenM` \ (rhs', fv_rhs') ->
338 339 340 341 342
    let
	mb_bad = validRuleLhs ids lhs'
    in
    checkErr (isNothing mb_bad)
	     (badRuleLhsErr rule_name lhs' mb_bad)	`thenM_`
343
    let
344
	bad_vars = [var | var <- ids, not (var `elemNameSet` fv_lhs')]
345
    in
346
    mappM (addErr . badRuleVar rule_name) bad_vars	`thenM_`
347 348
    returnM (HsRule rule_name act vars' lhs' fv_lhs' rhs' fv_rhs',
	     fv_vars `plusFV` fv_lhs' `plusFV` fv_rhs')
349
  where
350
    doc = text "In the transformation rule" <+> ftext rule_name
351 352 353 354
  
    get_var (RuleBndr v)      = v
    get_var (RuleBndrSig v _) = v

355 356 357 358 359
    rn_var (RuleBndr (L loc v), id)
	= returnM (RuleBndr (L loc id), emptyFVs)
    rn_var (RuleBndrSig (L loc v) t, id)
	= rnHsTypeFVs doc t	`thenM` \ (t', fvs) ->
	  returnM (RuleBndrSig (L loc id) t', fvs)
360 361 362 363 364

badRuleVar name var
  = sep [ptext SLIT("Rule") <+> doubleQuotes (ftext name) <> colon,
	 ptext SLIT("Forall'd variable") <+> quotes (ppr var) <+> 
		ptext SLIT("does not appear on left hand side")]
365 366
\end{code}

367 368 369 370 371
Note [Rule LHS validity checking]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Check the shape of a transformation rule LHS.  Currently we only allow
LHSs of the form @(f e1 .. en)@, where @f@ is not one of the
@forall@'d variables.  
372

373 374 375
We used restrict the form of the 'ei' to prevent you writing rules
with LHSs with a complicated desugaring (and hence unlikely to match);
(e.g. a case expression is not allowed: too elaborate.)
376

377 378 379 380
But there are legitimate non-trivial args ei, like sections and
lambdas.  So it seems simmpler not to check at all, and that is why
check_e is commented out.
	
381
\begin{code}
382
validRuleLhs :: [Name] -> LHsExpr Name -> Maybe (HsExpr Name)
383 384
-- Nothing => OK
-- Just e  => Not ok, and e is the offending expression
385
validRuleLhs foralls lhs
386
  = checkl lhs
387
  where
388 389 390 391
    checkl (L loc e) = check e

    check (OpApp e1 op _ e2)		  = checkl op `seqMaybe` checkl_e e1 `seqMaybe` checkl_e e2
    check (HsApp e1 e2) 		  = checkl e1 `seqMaybe` checkl_e e2
392 393 394
    check (HsVar v) | v `notElem` foralls = Nothing
    check other				  = Just other 	-- Failure

395 396
	-- Check an argument
    checkl_e (L loc e) = Nothing 	-- Was (check_e e); see Note [Rule LHS validity checking]
397

398
{-	Commented out; see Note [Rule LHS validity checking] above 
399
    check_e (HsVar v)     = Nothing
400
    check_e (HsPar e) 	  = checkl_e e
401 402 403
    check_e (HsLit e) 	  = Nothing
    check_e (HsOverLit e) = Nothing

404 405 406 407 408
    check_e (OpApp e1 op _ e2) 	 = checkl_e e1 `seqMaybe` checkl_e op `seqMaybe` checkl_e e2
    check_e (HsApp e1 e2)      	 = checkl_e e1 `seqMaybe` checkl_e e2
    check_e (NegApp e _)       	 = checkl_e e
    check_e (ExplicitList _ es)	 = checkl_es es
    check_e (ExplicitTuple es _) = checkl_es es
409 410
    check_e other		 = Just other	-- Fails

411
    checkl_es es = foldr (seqMaybe . checkl_e) Nothing es
412
-}
413 414 415 416 417 418 419

badRuleLhsErr name lhs (Just bad_e)
  = sep [ptext SLIT("Rule") <+> ftext name <> colon,
	 nest 4 (vcat [ptext SLIT("Illegal expression:") <+> ppr bad_e, 
		       ptext SLIT("in left-hand side:") <+> ppr lhs])]
    $$
    ptext SLIT("LHS must be of form (f e1 .. en) where f is not forall'd")
420 421
\end{code}

422

423 424
%*********************************************************
%*							*
425
\subsection{Type, class and iface sig declarations}
426 427 428 429 430 431 432 433 434
%*							*
%*********************************************************

@rnTyDecl@ uses the `global name function' to create a new type
declaration in which local names have been replaced by their original
names, reporting any unknown names.

Renaming type variables is a pain. Because they now contain uniques,
it is necessary to pass in an association list which maps a parsed
435 436 437 438 439 440
tyvar to its @Name@ representation.
In some cases (type signatures of values),
it is even necessary to go over the type first
in order to get the set of tyvars used by it, make an assoc list,
and then go over it again to rename the tyvars!
However, we can also do some scoping checks at the same time.
441 442

\begin{code}
443 444 445
rnTyClDecl (ForeignType {tcdLName = name, tcdFoType = fo_type, tcdExtName = ext_name})
  = lookupLocatedTopBndrRn name		`thenM` \ name' ->
    returnM (ForeignType {tcdLName = name', tcdFoType = fo_type, tcdExtName = ext_name},
446
	     emptyFVs)
447

448
rnTyClDecl (TyData {tcdND = new_or_data, tcdCtxt = context, tcdLName = tycon,
449
		    tcdTyVars = tyvars, tcdCons = condecls, 
450
		    tcdKindSig = sig, tcdDerivs = derivs})
451
  | is_vanilla	-- Normal Haskell data type decl
452 453 454
  = ASSERT( isNothing sig )	-- In normal H98 form, kind signature on the 
				-- data type is syntactically illegal
    bindTyVarsRn data_doc tyvars		$ \ tyvars' ->
455 456 457 458 459 460
    do	{ tycon' <- lookupLocatedTopBndrRn tycon
	; context' <- rnContext data_doc context
	; (derivs', deriv_fvs) <- rn_derivs derivs
	; checkDupNames data_doc con_names
	; condecls' <- rnConDecls (unLoc tycon') condecls
	; returnM (TyData {tcdND = new_or_data, tcdCtxt = context', tcdLName = tycon',
461
			   tcdTyVars = tyvars', tcdKindSig = Nothing, tcdCons = condecls', 
462 463 464 465 466 467 468
			   tcdDerivs = derivs'}, 
		   delFVs (map hsLTyVarName tyvars')	$
	     	   extractHsCtxtTyNames context'	`plusFV`
	     	   plusFVs (map conDeclFVs condecls') `plusFV`
	     	   deriv_fvs) }

  | otherwise	-- GADT
469 470 471
  = do	{ tycon' <- lookupLocatedTopBndrRn tycon
	; checkTc (null (unLoc context)) (badGadtStupidTheta tycon)
    	; tyvars' <- bindTyVarsRn data_doc tyvars 
472 473 474 475 476 477 478 479
				  (\ tyvars' -> return tyvars')
		-- For GADTs, the type variables in the declaration 
		-- do not scope over the constructor signatures
		-- 	data T a where { T1 :: forall b. b-> b }
	; (derivs', deriv_fvs) <- rn_derivs derivs
	; checkDupNames data_doc con_names
	; condecls' <- rnConDecls (unLoc tycon') condecls
	; returnM (TyData {tcdND = new_or_data, tcdCtxt = noLoc [], tcdLName = tycon',
480
			   tcdTyVars = tyvars', tcdCons = condecls', tcdKindSig = sig,
481 482 483
			   tcdDerivs = derivs'}, 
	     	   plusFVs (map conDeclFVs condecls') `plusFV` deriv_fvs) }

sof's avatar
sof committed
484
  where
485 486
    is_vanilla = case condecls of	-- Yuk
		     [] 		   -> True
487
		     L _ (ConDecl { con_res = ResTyH98 }) : _  -> True
488 489
		     other		   -> False

490
    data_doc = text "In the data type declaration for" <+> quotes (ppr tycon)
491 492
    con_names = map con_names_helper condecls

493
    con_names_helper (L _ c) = con_name c
494

495
    rn_derivs Nothing   = returnM (Nothing, emptyFVs)
496 497
    rn_derivs (Just ds) = rnLHsTypes data_doc ds	`thenM` \ ds' -> 
			  returnM (Just ds', extractHsTyNames_s ds')
498
    
499 500
rnTyClDecl (TySynonym {tcdLName = name, tcdTyVars = tyvars, tcdSynRhs = ty})
  = lookupLocatedTopBndrRn name			`thenM` \ name' ->
501
    bindTyVarsRn syn_doc tyvars 		$ \ tyvars' ->
502
    rnHsTypeFVs syn_doc ty			`thenM` \ (ty', fvs) ->
503 504 505
    returnM (TySynonym {tcdLName = name', tcdTyVars = tyvars', 
			tcdSynRhs = ty'},
	     delFVs (map hsLTyVarName tyvars') fvs)
sof's avatar
sof committed
506
  where
507
    syn_doc = text "In the declaration for type synonym" <+> quotes (ppr name)
508

509
rnTyClDecl (ClassDecl {tcdCtxt = context, tcdLName = cname, 
510
		       tcdTyVars = tyvars, tcdFDs = fds, tcdSigs = sigs, 
511 512
		       tcdMeths = mbinds})
  = lookupLocatedTopBndrRn cname		`thenM` \ cname' ->
sof's avatar
sof committed
513

514
	-- Tyvars scope over superclass context and method signatures
515 516 517
    bindTyVarsRn cls_doc tyvars			( \ tyvars' ->
	rnContext cls_doc context	`thenM` \ context' ->
	rnFds cls_doc fds		`thenM` \ fds' ->
518
	renameSigs okClsDclSig sigs	`thenM` \ sigs' ->
519 520
	returnM   (tyvars', context', fds', sigs')
    )	`thenM` \ (tyvars', context', fds', sigs') ->
521

522
	-- Check the signatures
523
	-- First process the class op sigs (op_sigs), then the fixity sigs (non_op_sigs).
524
    let
525
	sig_rdr_names_w_locs   = [op | L _ (TypeSig op _) <- sigs]
526
    in
527
    checkDupNames sig_doc sig_rdr_names_w_locs	`thenM_` 
528 529 530 531 532
	-- Typechecker is responsible for checking that we only
	-- give default-method bindings for things in this class.
	-- The renamer *could* check this for class decls, but can't
	-- for instance decls.

533
   	-- The newLocals call is tiresome: given a generic class decl
534 535 536 537 538 539 540
	--	class C a where
	--	  op :: a -> a
	--	  op {| x+y |} (Inl a) = ...
	--	  op {| x+y |} (Inr b) = ...
	--	  op {| a*b |} (a*b)   = ...
	-- we want to name both "x" tyvars with the same unique, so that they are
	-- easy to group together in the typechecker.  
541 542 543
    extendTyVarEnvForMethodBinds tyvars' (
   	 getLocalRdrEnv					`thenM` \ name_env ->
   	 let
544 545 546 547
 	     meth_rdr_names_w_locs = collectHsBindLocatedBinders mbinds
 	     gen_rdr_tyvars_w_locs = 
		[ tv | tv <- extractGenericPatTyVars mbinds,
 		      not (unLoc tv `elemLocalRdrEnv` name_env) ]
548 549
   	 in
   	 checkDupNames meth_doc meth_rdr_names_w_locs	`thenM_`
550
   	 newLocalsRn gen_rdr_tyvars_w_locs	`thenM` \ gen_tyvars ->
551
   	 rnMethodBinds (unLoc cname') (mkSigTvFn sigs') gen_tyvars mbinds
552 553 554 555 556
    ) `thenM` \ (mbinds', meth_fvs) ->

    returnM (ClassDecl { tcdCtxt = context', tcdLName = cname', tcdTyVars = tyvars',
			 tcdFDs = fds', tcdSigs = sigs', tcdMeths = mbinds'},
	     delFVs (map hsLTyVarName tyvars')	$
557
	     extractHsCtxtTyNames context'	    `plusFV`
558
	     plusFVs (map extractFunDepNames (map unLoc fds'))  `plusFV`
559 560 561 562 563 564
	     hsSigsFVs sigs'		  	    `plusFV`
	     meth_fvs)
  where
    meth_doc = text "In the default-methods for class"	<+> ppr cname
    cls_doc  = text "In the declaration for class" 	<+> ppr cname
    sig_doc  = text "In the signatures for class"  	<+> ppr cname
565 566 567 568

badGadtStupidTheta tycon
  = vcat [ptext SLIT("No context is allowed on a GADT-style data declaration"),
	  ptext SLIT("(You can put a context on each contructor, though.)")]
569 570
\end{code}

571 572
%*********************************************************
%*							*
573
\subsection{Support code for type/data declarations}
574 575 576 577
%*							*
%*********************************************************

\begin{code}
578
rnConDecls :: Name -> [LConDecl RdrName] -> RnM [LConDecl Name]
579
rnConDecls tycon condecls
580
  = mappM (wrapLocM rnConDecl) condecls
581

582
rnConDecl :: ConDecl RdrName -> RnM (ConDecl Name)
583 584
rnConDecl (ConDecl name expl tvs cxt details res_ty)
  = do	{ addLocM checkConName name
sof's avatar
sof committed
585

586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604
	; new_name <- lookupLocatedTopBndrRn name
	; name_env <- getLocalRdrEnv
	
	-- For H98 syntax, the tvs are the existential ones
	-- For GADT syntax, the tvs are all the quantified tyvars
	-- Hence the 'filter' in the ResTyH98 case only
	; let not_in_scope  = not . (`elemLocalRdrEnv` name_env) . unLoc
	      arg_tys       = hsConArgs details
	      implicit_tvs  = case res_ty of
	      	    		ResTyH98 -> filter not_in_scope $
						get_rdr_tvs arg_tys
	      	    		ResTyGADT ty -> get_rdr_tvs (ty : arg_tys)
	      tvs' = case expl of
	        	Explicit -> tvs
		    	Implicit -> userHsTyVarBndrs implicit_tvs

	; bindTyVarsRn doc tvs' $ \new_tyvars -> do
	{ new_context <- rnContext doc cxt
        ; new_details <- rnConDetails doc details
605 606
        ; (new_details', new_res_ty)  <- rnConResult doc new_details res_ty
        ; return (ConDecl new_name expl new_tyvars new_context new_details' new_res_ty) }}
607 608
  where
    doc = text "In the definition of data constructor" <+> quotes (ppr name)
609 610
    get_rdr_tvs tys  = extractHsRhoRdrTyVars cxt (noLoc (HsTupleTy Boxed tys))

611 612 613
rnConResult _ details ResTyH98 = return (details, ResTyH98)

rnConResult doc details (ResTyGADT ty) = do
614
    ty' <- rnHsSigType doc ty
615 616 617 618 619 620
    let (arg_tys, res_ty) = splitHsFunType ty'
	-- We can split it up, now the renamer has dealt with fixities
    case details of
	PrefixCon _xs -> ASSERT( null _xs ) return (PrefixCon arg_tys, ResTyGADT res_ty)
	RecCon fields -> return (details, ResTyGADT ty')
	InfixCon {}   -> panic "rnConResult"
621

622
rnConDetails doc (PrefixCon tys)
623
  = mappM (rnLHsType doc) tys	`thenM` \ new_tys  ->
624
    returnM (PrefixCon new_tys)
sof's avatar
sof committed
625

626
rnConDetails doc (InfixCon ty1 ty2)
627 628
  = rnLHsType doc ty1  		`thenM` \ new_ty1 ->
    rnLHsType doc ty2  		`thenM` \ new_ty2 ->
629
    returnM (InfixCon new_ty1 new_ty2)
630

631
rnConDetails doc (RecCon fields)
632
  = checkDupNames doc field_names	`thenM_`
633 634
    mappM (rnField doc) fields		`thenM` \ new_fields ->
    returnM (RecCon new_fields)
sof's avatar
sof committed
635
  where
636
    field_names = [fld | (fld, _) <- fields]
637

638
rnField doc (name, ty)
639
  = lookupLocatedTopBndrRn name	`thenM` \ new_name ->
640
    rnLHsType doc ty		`thenM` \ new_ty ->
641
    returnM (new_name, new_ty) 
642

643 644 645 646 647 648 649 650 651 652
-- This data decl will parse OK
--	data T = a Int
-- treating "a" as the constructor.
-- It is really hard to make the parser spot this malformation.
-- So the renamer has to check that the constructor is legal
--
-- We can get an operator as the constructor, even in the prefix form:
--	data T = :% Int Int
-- from interface files, which always print in prefix form

653 654 655 656
checkConName name = checkErr (isRdrDataCon name) (badDataCon name)

badDataCon name
   = hsep [ptext SLIT("Illegal data constructor name"), quotes (ppr name)]
657 658
\end{code}

659

660 661 662 663 664
%*********************************************************
%*							*
\subsection{Support code to rename types}
%*							*
%*********************************************************
665

666
\begin{code}
667
rnFds :: SDoc -> [Located (FunDep RdrName)] -> RnM [Located (FunDep Name)]
668 669

rnFds doc fds
670
  = mappM (wrapLocM rn_fds) fds
671 672
  where
    rn_fds (tys1, tys2)
673 674 675
      =	rnHsTyVars doc tys1		`thenM` \ tys1' ->
	rnHsTyVars doc tys2		`thenM` \ tys2' ->
	returnM (tys1', tys2')
676

677
rnHsTyVars doc tvs  = mappM (rnHsTyvar doc) tvs
678
rnHsTyvar doc tyvar = lookupOccRn tyvar
679
\end{code}
680

681 682 683 684 685 686 687

%*********************************************************
%*							*
		Splices
%*							*
%*********************************************************

688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706
Note [Splices]
~~~~~~~~~~~~~~
Consider
	f = ...
	h = ...$(thing "f")...

The splice can expand into literally anything, so when we do dependency
analysis we must assume that it might mention 'f'.  So we simply treat
all locally-defined names as mentioned by any splice.  This is terribly
brutal, but I don't see what else to do.  For example, it'll mean
that every locally-defined thing will appear to be used, so no unused-binding
warnings.  But if we miss the dependency, then we might typecheck 'h' before 'f',
and that will crash the type checker because 'f' isn't in scope.

Currently, I'm not treating a splice as also mentioning every import,
which is a bit inconsistent -- but there are a lot of them.  We might
thereby get some bogus unused-import warnings, but we won't crash the
type checker.  Not very satisfactory really.

707 708 709
\begin{code}
rnSplice :: HsSplice RdrName -> RnM (HsSplice Name, FreeVars)
rnSplice (HsSplice n expr)
710 711 712 713 714 715 716 717 718 719 720 721 722
  = do	{ checkTH expr "splice"
	; loc  <- getSrcSpanM
	; [n'] <- newLocalsRn [L loc n]
	; (expr', fvs) <- rnLExpr expr

	-- Ugh!  See Note [Splices] above
	; lcl_rdr <- getLocalRdrEnv
	; gbl_rdr <- getGlobalRdrEnv
	; let gbl_names = mkNameSet [gre_name gre | gre <- globalRdrEnvElts gbl_rdr, 
						    isLocalGRE gre]
	      lcl_names = mkNameSet (occEnvElts lcl_rdr)

	; return (HsSplice n' expr', fvs `plusFV` lcl_names `plusFV` gbl_names) }
723 724 725 726 727 728 729 730 731

#ifdef GHCI 
checkTH e what = returnM ()	-- OK
#else
checkTH e what 	-- Raise an error in a stage-1 compiler
  = addErr (vcat [ptext SLIT("Template Haskell") <+> text what <+>  
	          ptext SLIT("illegal in a stage-1 compiler"),
	          nest 2 (ppr e)])
#endif   
732
\end{code}