RnSource.lhs 31.6 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, isRdrTyVar, 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 Monad		( liftM )
46
import BasicTypes       ( Boxity(..) )
47 48
\end{code}

49
@rnSourceDecl@ `renames' declarations.
50 51 52 53 54 55
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.
56 57
(Some of this checking has now been moved to module @TcMonoType@,
since we don't have functional dependency information at this point.)
58 59 60
\item
Checks that all variable occurences are defined.
\item 
61
Checks the @(..)@ etc constraints in the export list.
62 63 64
\end{enumerate}


65
\begin{code}
66
rnSrcDecls :: HsGroup RdrName -> RnM (TcGblEnv, HsGroup Name)
67

68
rnSrcDecls (HsGroup { hs_valds  = val_decls,
69 70 71 72 73 74
		      hs_tyclds = tycl_decls,
		      hs_instds = inst_decls,
		      hs_fixds  = fix_decls,
		      hs_depds  = deprec_decls,
		      hs_fords  = foreign_decls,
		      hs_defds  = default_decls,
75
		      hs_ruleds = rule_decls })
76 77 78

 = do {		-- Deal with deprecations (returns only the extra deprecations)
	deprecs <- rnSrcDeprecDecls deprec_decls ;
79 80 81 82 83
	updGblEnv (\gbl -> gbl { tcg_deprecs = tcg_deprecs gbl `plusDeprecs` deprecs })
		  $ do {

		-- Deal with top-level fixity decls 
		-- (returns the total new fixity env)
84
        rn_fix_decls <- rnSrcFixityDecls fix_decls ;
85
	fix_env <- rnSrcFixityDeclsEnv rn_fix_decls ;
86 87 88
	updGblEnv (\gbl -> gbl { tcg_fix_env = fix_env })
		  $ do {

89
		-- Rename other declarations
90
	traceRn (text "Start rnmono") ;
91
	(rn_val_decls, bind_dus) <- rnTopBinds val_decls ;
92
	traceRn (text "finish rnmono" <+> ppr rn_val_decls) ;
93 94 95 96 97 98 99 100

		-- 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.
101 102 103 104 105 106 107 108 109 110
	(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 ;
111 112
	
	let {
113 114
           rn_at_decls = concat 
			   [ats | L _ (InstDecl _ _ _ ats) <- rn_inst_decls] ;
115
	   rn_group = HsGroup { hs_valds  = rn_val_decls,
116
			    	hs_tyclds = rn_tycl_decls ++ rn_at_decls,
117
			    	hs_instds = rn_inst_decls,
118
			    	hs_fixds  = rn_fix_decls,
119 120 121
			    	hs_depds  = [],
			    	hs_fords  = rn_foreign_decls,
			    	hs_defds  = rn_default_decls,
122
			    	hs_ruleds = rn_rule_decls } ;
123

124
	   other_fvs = plusFVs [src_fvs1, src_fvs2, src_fvs3, 
125
				src_fvs4, src_fvs5] ;
126
	   src_dus = bind_dus `plusDU` usesOnly other_fvs 
127 128 129 130
		-- 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.
131 132
	} ;

133
	traceRn (text "finish rnSrc" <+> ppr rn_group) ;
134
	traceRn (text "finish Dus" <+> ppr src_dus ) ;
135
	tcg_env <- getGblEnv ;
136
	return (tcg_env `addTcgDUs` src_dus, rn_group)
137
    }}}
138 139 140 141 142

rnTyClDecls :: [LTyClDecl RdrName] -> RnM [LTyClDecl Name]
rnTyClDecls tycl_decls = do 
  (decls', fvs) <- mapFvRn (wrapLocFstM rnTyClDecl) tycl_decls
  return decls'
143 144 145

addTcgDUs :: TcGblEnv -> DefUses -> TcGblEnv 
addTcgDUs tcg_env dus = tcg_env { tcg_dus = tcg_dus tcg_env `plusDU` dus }
146 147 148 149 150 151 152 153 154 155
\end{code}


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

\begin{code}
156
rnSrcFixityDecls :: [LFixitySig RdrName] -> RnM [LFixitySig Name]
157
rnSrcFixityDecls fix_decls
158 159 160 161 162
    = 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))
163 164 165 166 167 168
    = 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
169 170 171
         return [ L loc (FixitySig (L nameLoc name) fixity)
                      | name <- names ]

172
rnSrcFixityDeclsEnv :: [LFixitySig Name] -> RnM FixityEnv
173
rnSrcFixityDeclsEnv fix_decls
174
  = getGblEnv					`thenM` \ gbl_env ->
175
    foldlM rnFixityDeclEnv (tcg_fix_env gbl_env) 
176 177
	    fix_decls				 	`thenM` \ fix_env ->
    traceRn (text "fixity env" <+> pprFixEnv fix_env)	`thenM_`
178 179
    returnM fix_env

180 181 182 183 184 185 186 187 188
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
189 190 191 192 193

pprFixEnv :: FixityEnv -> SDoc
pprFixEnv env 
  = pprWithCommas (\ (FixItem n f _) -> ppr f <+> ppr n)
		  (nameEnvElts env)
194

195
dupFixityDecl loc rdr_name
196
  = vcat [ptext SLIT("Multiple fixity declarations for") <+> quotes (ppr rdr_name),
197 198
	  ptext SLIT("also at ") <+> ppr loc
	]
199 200 201 202 203 204 205 206 207 208 209 210 211 212
\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}
213
rnSrcDeprecDecls :: [LDeprecDecl RdrName] -> RnM Deprecations
214 215 216 217
rnSrcDeprecDecls [] 
  = returnM NoDeprecs

rnSrcDeprecDecls decls
218 219
  = mappM (addLocM rn_deprec) decls	`thenM` \ pairs_s ->
    returnM (DeprecSome (mkNameEnv (concat pairs_s)))
220
 where
221
   rn_deprec (Deprecation rdr_name txt)
222 223
     = lookupLocalDataTcNames rdr_name	`thenM` \ names ->
       returnM [(name, (nameOccName name, txt)) | name <- names]
224 225 226 227

checkModDeprec :: Maybe DeprecTxt -> Deprecations
-- Check for a module deprecation; done once at top level
checkModDeprec Nothing    = NoDeprecs
228
checkModDeprec (Just txt) = DeprecAll txt
229
\end{code}
230

231 232 233 234 235
%*********************************************************
%*							*
\subsection{Source code declarations}
%*							*
%*********************************************************
236

237
\begin{code}
238 239 240
rnDefaultDecl (DefaultDecl tys)
  = mapFvRn (rnHsTypeFVs doc_str) tys	`thenM` \ (tys', fvs) ->
    returnM (DefaultDecl tys', fvs)
241
  where
242
    doc_str = text "In a `default' declaration"
243 244
\end{code}

245 246 247 248 249 250 251
%*********************************************************
%*							*
\subsection{Foreign declarations}
%*							*
%*********************************************************

\begin{code}
Simon Marlow's avatar
Simon Marlow committed
252
rnHsForeignDecl (ForeignImport name ty spec)
253
  = lookupLocatedTopBndrRn name	        `thenM` \ name' ->
254
    rnHsTypeFVs (fo_decl_msg name) ty	`thenM` \ (ty', fvs) ->
Simon Marlow's avatar
Simon Marlow committed
255
    returnM (ForeignImport name' ty' spec, fvs)
256

Simon Marlow's avatar
Simon Marlow committed
257
rnHsForeignDecl (ForeignExport name ty spec)
258
  = lookupLocatedOccRn name	        `thenM` \ name' ->
259
    rnHsTypeFVs (fo_decl_msg name) ty  	`thenM` \ (ty', fvs) ->
Simon Marlow's avatar
Simon Marlow committed
260
    returnM (ForeignExport name' ty' spec, fvs )
261 262 263
	-- 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
264

265
fo_decl_msg name = ptext SLIT("In the foreign declaration for") <+> ppr name
266 267 268 269 270 271 272 273 274 275
\end{code}


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

\begin{code}
276
rnSrcInstDecl (InstDecl inst_ty mbinds uprags ats)
277
	-- Used for both source and interface file decls
278
  = rnHsSigType (text "an instance decl") inst_ty	`thenM` \ inst_ty' ->
279

280 281 282 283 284 285 286 287 288 289 290
	-- Rename the associated types
	-- The typechecker (not the renamer) checks that all 
	-- the declarations are for the right class
    let
	at_doc   = text "In the associated types in an instance declaration"
	at_names = map (head . tyClDeclNames . unLoc) ats
	(_, rdrCtxt, _, _) = splitHsInstDeclTy (unLoc inst_ty)
    in
    checkDupNames at_doc at_names		`thenM_`
    rnATDefs rdrCtxt ats			`thenM` \ (ats', at_fvs) ->

291 292 293
	-- Rename the bindings
	-- The typechecker (not the renamer) checks that all 
	-- the bindings are for the right class
294
    let
295
	meth_doc    = text "In the bindings in an instance declaration"
296 297
	meth_names  = collectHsBindLocatedBinders mbinds
	(inst_tyvars, _, cls,_) = splitHsInstDeclTy (unLoc inst_ty')
298
    in
299
    checkDupNames meth_doc meth_names 	`thenM_`
300
    extendTyVarEnvForMethodBinds inst_tyvars (		
301 302
	-- (Slightly strangely) the forall-d tyvars scope over
	-- the method bindings too
303 304
	rnMethodBinds cls (\n->[]) 	-- No scoped tyvars
		      [] mbinds
305
    )						`thenM` \ (mbinds', meth_fvs) ->
306 307 308 309 310 311 312
	-- 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
313
    let 
314
	binders = collectHsBindBinders mbinds'
315
	ok_sig  = okInstDclSig (mkNameSet binders)
316
    in
317
    bindLocalNames binders (renameSigs ok_sig uprags)	`thenM` \ uprags' ->
318

319 320 321
    returnM (InstDecl inst_ty' mbinds' uprags' ats',
	     meth_fvs `plusFV` at_fvs
		      `plusFV` hsSigsFVs uprags'
322
		      `plusFV` extractHsTyNames inst_ty')
323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348
             -- We return the renamed associated data type declarations so
             -- that they can be entered into the list of type declarations
             -- for the binding group, but we also keep a copy in the instance.
             -- The latter is needed for well-formedness checks in the type
             -- checker (eg, to ensure that all ATs of the instance actually
             -- receive a declaration). 
	     -- NB: Even the copies in the instance declaration carry copies of
	     --     the instance context after renaming.  This is a bit
	     --     strange, but should not matter (and it would be more work
	     --     to remove the context).
\end{code}

Renaming of the associated data definitions requires adding the instance
context, as the rhs of an AT declaration may use ATs from classes in the
context.

\begin{code}
rnATDefs :: HsContext RdrName -> [LTyClDecl RdrName] 
	  -> RnM ([LTyClDecl Name], FreeVars)
rnATDefs ctxt atDecls = 
  mapFvRn (wrapLocFstM addCtxtAndRename) atDecls
  where
    -- The parser won't accept anything, but a data declaration
    addCtxtAndRename ty@TyData {tcdCtxt = L l tyCtxt} = 
      rnTyClDecl (ty {tcdCtxt = L l (ctxt ++ tyCtxt)})
      -- The source loc is somewhat half hearted... -=chak
349 350
\end{code}

351 352 353 354 355 356 357
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
358
	extendTyVarEnvFVRn (map hsLTyVarName tyvars) thing_inside
359 360 361 362 363
    else
	thing_inside
\end{code}


364 365 366 367 368 369 370
%*********************************************************
%*							*
\subsection{Rules}
%*							*
%*********************************************************

\begin{code}
371
rnHsRuleDecl (HsRule rule_name act vars lhs fv_lhs rhs fv_rhs)
372
  = bindPatSigTyVarsFV (collectRuleBndrSigTys vars)	$
373

374
    bindLocatedLocalsFV doc (map get_var vars)		$ \ ids ->
375
    mapFvRn rn_var (vars `zip` ids)		`thenM` \ (vars', fv_vars) ->
376

377 378
    rnLExpr lhs					`thenM` \ (lhs', fv_lhs') ->
    rnLExpr rhs					`thenM` \ (rhs', fv_rhs') ->
379 380 381

    checkValidRule rule_name ids lhs' fv_lhs'	`thenM_`

382 383
    returnM (HsRule rule_name act vars' lhs' fv_lhs' rhs' fv_rhs',
	     fv_vars `plusFV` fv_lhs' `plusFV` fv_rhs')
384
  where
385
    doc = text "In the transformation rule" <+> ftext rule_name
386 387 388 389
  
    get_var (RuleBndr v)      = v
    get_var (RuleBndrSig v _) = v

390 391 392 393 394
    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)
395 396 397 398 399

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")]
400 401
\end{code}

402 403 404 405 406
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.  
407

408 409 410
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.)
411

412 413 414 415
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.
	
416
\begin{code}
417 418 419 420 421 422 423 424 425 426
checkValidRule rule_name ids lhs' fv_lhs'
  = do 	{ 	-- Check for the form of the LHS
	  case (validRuleLhs ids lhs') of
		Nothing  -> return ()
		Just bad -> failWithTc (badRuleLhsErr rule_name lhs' bad)

		-- Check that LHS vars are all bound
	; let bad_vars = [var | var <- ids, not (var `elemNameSet` fv_lhs')]
	; mappM (addErr . badRuleVar rule_name) bad_vars }

427
validRuleLhs :: [Name] -> LHsExpr Name -> Maybe (HsExpr Name)
428 429
-- Nothing => OK
-- Just e  => Not ok, and e is the offending expression
430
validRuleLhs foralls lhs
431
  = checkl lhs
432
  where
433 434 435 436
    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
437 438 439
    check (HsVar v) | v `notElem` foralls = Nothing
    check other				  = Just other 	-- Failure

440 441
	-- Check an argument
    checkl_e (L loc e) = Nothing 	-- Was (check_e e); see Note [Rule LHS validity checking]
442

443
{-	Commented out; see Note [Rule LHS validity checking] above 
444
    check_e (HsVar v)     = Nothing
445
    check_e (HsPar e) 	  = checkl_e e
446 447 448
    check_e (HsLit e) 	  = Nothing
    check_e (HsOverLit e) = Nothing

449 450 451 452 453
    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
454 455
    check_e other		 = Just other	-- Fails

456
    checkl_es es = foldr (seqMaybe . checkl_e) Nothing es
457
-}
458

459
badRuleLhsErr name lhs bad_e
460 461 462 463 464
  = 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")
465 466
\end{code}

467

468 469
%*********************************************************
%*							*
470
\subsection{Type, class and iface sig declarations}
471 472 473 474 475 476 477 478 479
%*							*
%*********************************************************

@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
480 481 482 483 484 485
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.
486 487

\begin{code}
488 489 490
rnTyClDecl (ForeignType {tcdLName = name, tcdFoType = fo_type, tcdExtName = ext_name})
  = lookupLocatedTopBndrRn name		`thenM` \ name' ->
    returnM (ForeignType {tcdLName = name', tcdFoType = fo_type, tcdExtName = ext_name},
491
	     emptyFVs)
492

493
rnTyClDecl (TyData {tcdND = new_or_data, tcdCtxt = context, tcdLName = tycon,
494 495
		    tcdTyVars = tyvars, tcdTyPats = typatsMaybe, 
		    tcdCons = condecls, tcdKindSig = sig, tcdDerivs = derivs})
496
  | is_vanilla	-- Normal Haskell data type decl
497 498 499
  = ASSERT( isNothing sig )	-- In normal H98 form, kind signature on the 
				-- data type is syntactically illegal
    bindTyVarsRn data_doc tyvars		$ \ tyvars' ->
500 501
    do	{ tycon' <- lookupLocatedTopBndrRn tycon
	; context' <- rnContext data_doc context
502
	; typats' <- rnTyPats data_doc typatsMaybe
503 504 505
	; (derivs', deriv_fvs) <- rn_derivs derivs
	; checkDupNames data_doc con_names
	; condecls' <- rnConDecls (unLoc tycon') condecls
506 507 508 509
	; returnM (TyData {tcdND = new_or_data, tcdCtxt = context', 
			   tcdLName = tycon', tcdTyVars = tyvars', 
			   tcdTyPats = typats', tcdKindSig = Nothing, 
			   tcdCons = condecls', tcdDerivs = derivs'}, 
510 511
		   delFVs (map hsLTyVarName tyvars')	$
	     	   extractHsCtxtTyNames context'	`plusFV`
512
	     	   plusFVs (map conDeclFVs condecls')   `plusFV`
513 514 515
	     	   deriv_fvs) }

  | otherwise	-- GADT
516 517
  = ASSERT( null typats )       -- GADTs cannot have type patterns for now
    do	{ tycon' <- lookupLocatedTopBndrRn tycon
518 519
	; checkTc (null (unLoc context)) (badGadtStupidTheta tycon)
    	; tyvars' <- bindTyVarsRn data_doc tyvars 
520 521 522 523 524 525 526
				  (\ 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
527 528 529 530
	; returnM (TyData {tcdND = new_or_data, tcdCtxt = noLoc [], 
			   tcdLName = tycon', tcdTyVars = tyvars', 
			   tcdTyPats = Nothing, tcdKindSig = sig,
			   tcdCons = condecls', tcdDerivs = derivs'}, 
531 532
	     	   plusFVs (map conDeclFVs condecls') `plusFV` deriv_fvs) }

sof's avatar
sof committed
533
  where
534 535
    is_vanilla = case condecls of	-- Yuk
		     [] 		   -> True
536
		     L _ (ConDecl { con_res = ResTyH98 }) : _  -> True
537 538
		     other		   -> False

539
    data_doc = text "In the data type declaration for" <+> quotes (ppr tycon)
540 541
    con_names = map con_names_helper condecls

542
    con_names_helper (L _ c) = con_name c
543

544
    rn_derivs Nothing   = returnM (Nothing, emptyFVs)
545 546
    rn_derivs (Just ds) = rnLHsTypes data_doc ds	`thenM` \ ds' -> 
			  returnM (Just ds', extractHsTyNames_s ds')
547
    
548 549
rnTyClDecl (TySynonym {tcdLName = name, tcdTyVars = tyvars, tcdSynRhs = ty})
  = lookupLocatedTopBndrRn name			`thenM` \ name' ->
550
    bindTyVarsRn syn_doc tyvars 		$ \ tyvars' ->
551
    rnHsTypeFVs syn_doc ty			`thenM` \ (ty', fvs) ->
552 553 554
    returnM (TySynonym {tcdLName = name', tcdTyVars = tyvars', 
			tcdSynRhs = ty'},
	     delFVs (map hsLTyVarName tyvars') fvs)
sof's avatar
sof committed
555
  where
556
    syn_doc = text "In the declaration for type synonym" <+> quotes (ppr name)
557

558
rnTyClDecl (ClassDecl {tcdCtxt = context, tcdLName = cname, 
559
		       tcdTyVars = tyvars, tcdFDs = fds, tcdSigs = sigs, 
560
		       tcdMeths = mbinds, tcdATs = ats})
561
  = lookupLocatedTopBndrRn cname		`thenM` \ cname' ->
sof's avatar
sof committed
562

563
	-- Tyvars scope over superclass context and method signatures
564 565 566
    bindTyVarsRn cls_doc tyvars			( \ tyvars' ->
	rnContext cls_doc context	`thenM` \ context' ->
	rnFds cls_doc fds		`thenM` \ fds' ->
567
	rnATs tyvars' ats		`thenM` \ (ats', ats_fvs) ->
568
	renameSigs okClsDclSig sigs	`thenM` \ sigs' ->
569 570 571 572 573 574 575 576
	returnM   (tyvars', context', fds', (ats', ats_fvs), sigs')
    )	`thenM` \ (tyvars', context', fds', (ats', ats_fvs), sigs') ->

	-- Check for duplicates among the associated types
    let
      at_rdr_names_w_locs      = [tcdLName ty | L _ ty <- ats]
    in
    checkDupNames at_doc at_rdr_names_w_locs   `thenM_`
577

578
	-- Check the signatures
579
	-- First process the class op sigs (op_sigs), then the fixity sigs (non_op_sigs).
580
    let
581
	sig_rdr_names_w_locs   = [op | L _ (TypeSig op _) <- sigs]
582
    in
583
    checkDupNames sig_doc sig_rdr_names_w_locs	`thenM_` 
584 585 586 587 588
	-- 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.

589
   	-- The newLocals call is tiresome: given a generic class decl
590 591 592 593 594 595 596
	--	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.  
597 598 599
    extendTyVarEnvForMethodBinds tyvars' (
   	 getLocalRdrEnv					`thenM` \ name_env ->
   	 let
600 601 602 603
 	     meth_rdr_names_w_locs = collectHsBindLocatedBinders mbinds
 	     gen_rdr_tyvars_w_locs = 
		[ tv | tv <- extractGenericPatTyVars mbinds,
 		      not (unLoc tv `elemLocalRdrEnv` name_env) ]
604 605
   	 in
   	 checkDupNames meth_doc meth_rdr_names_w_locs	`thenM_`
606
   	 newLocalsRn gen_rdr_tyvars_w_locs	`thenM` \ gen_tyvars ->
607
   	 rnMethodBinds (unLoc cname') (mkSigTvFn sigs') gen_tyvars mbinds
608 609
    ) `thenM` \ (mbinds', meth_fvs) ->

610 611 612
    returnM (ClassDecl { tcdCtxt = context', tcdLName = cname', 
			 tcdTyVars = tyvars', tcdFDs = fds', tcdSigs = sigs',
			 tcdMeths = mbinds', tcdATs = ats'},
613
	     delFVs (map hsLTyVarName tyvars')	$
614
	     extractHsCtxtTyNames context'	    `plusFV`
615
	     plusFVs (map extractFunDepNames (map unLoc fds'))  `plusFV`
616
	     hsSigsFVs sigs'		  	    `plusFV`
617 618
	     meth_fvs				    `plusFV`
	     ats_fvs)
619 620 621 622
  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
623
    at_doc   = text "In the associated types for class"	<+> ppr cname
624 625 626 627

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.)")]
628 629
\end{code}

630 631
%*********************************************************
%*							*
632
\subsection{Support code for type/data declarations}
633 634 635 636
%*							*
%*********************************************************

\begin{code}
637 638 639 640 641 642 643 644
-- Although, we are processing type patterns here, all type variables should
-- already be in scope (they are the same as in the 'tcdTyVars' field of the
-- type declaration to which these patterns belong)
--
rnTyPats :: SDoc -> Maybe [LHsType RdrName] -> RnM (Maybe [LHsType Name])
rnTyPats _   Nothing       = return Nothing
rnTyPats doc (Just typats) = liftM Just $ rnLHsTypes doc typats

645
rnConDecls :: Name -> [LConDecl RdrName] -> RnM [LConDecl Name]
646
rnConDecls tycon condecls
647
  = mappM (wrapLocM rnConDecl) condecls
648

649
rnConDecl :: ConDecl RdrName -> RnM (ConDecl Name)
650 651
rnConDecl (ConDecl name expl tvs cxt details res_ty)
  = do	{ addLocM checkConName name
sof's avatar
sof committed
652

653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671
	; 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
672 673
        ; (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) }}
674 675
  where
    doc = text "In the definition of data constructor" <+> quotes (ppr name)
676 677
    get_rdr_tvs tys  = extractHsRhoRdrTyVars cxt (noLoc (HsTupleTy Boxed tys))

678 679 680
rnConResult _ details ResTyH98 = return (details, ResTyH98)

rnConResult doc details (ResTyGADT ty) = do
681
    ty' <- rnHsSigType doc ty
682 683 684 685 686 687
    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"
688

689
rnConDetails doc (PrefixCon tys)
690
  = mappM (rnLHsType doc) tys	`thenM` \ new_tys  ->
691
    returnM (PrefixCon new_tys)
sof's avatar
sof committed
692

693
rnConDetails doc (InfixCon ty1 ty2)
694 695
  = rnLHsType doc ty1  		`thenM` \ new_ty1 ->
    rnLHsType doc ty2  		`thenM` \ new_ty2 ->
696
    returnM (InfixCon new_ty1 new_ty2)
697

698
rnConDetails doc (RecCon fields)
699
  = checkDupNames doc field_names	`thenM_`
700 701
    mappM (rnField doc) fields		`thenM` \ new_fields ->
    returnM (RecCon new_fields)
sof's avatar
sof committed
702
  where
703
    field_names = [fld | (fld, _) <- fields]
704

705
rnField doc (name, ty)
706
  = lookupLocatedTopBndrRn name	`thenM` \ new_name ->
707
    rnLHsType doc ty		`thenM` \ new_ty ->
708
    returnM (new_name, new_ty) 
709

710 711 712 713 714 715 716 717 718 719
-- 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

720 721 722 723
checkConName name = checkErr (isRdrDataCon name) (badDataCon name)

badDataCon name
   = hsep [ptext SLIT("Illegal data constructor name"), quotes (ppr name)]
724 725
\end{code}

726

727 728 729 730 731
%*********************************************************
%*							*
\subsection{Support code to rename types}
%*							*
%*********************************************************
732

733
\begin{code}
734
rnFds :: SDoc -> [Located (FunDep RdrName)] -> RnM [Located (FunDep Name)]
735 736

rnFds doc fds
737
  = mappM (wrapLocM rn_fds) fds
738 739
  where
    rn_fds (tys1, tys2)
740 741 742
      =	rnHsTyVars doc tys1		`thenM` \ tys1' ->
	rnHsTyVars doc tys2		`thenM` \ tys2' ->
	returnM (tys1', tys2')
743

744
rnHsTyVars doc tvs  = mappM (rnHsTyvar doc) tvs
745
rnHsTyvar doc tyvar = lookupOccRn tyvar
746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816

-- Rename associated data type declarations
--
rnATs :: [LHsTyVarBndr Name] -> [LTyClDecl RdrName] 
      -> RnM ([LTyClDecl Name], FreeVars)
rnATs classLTyVars ats
  = mapFvRn (wrapLocFstM rn_at) ats
  where
    -- The parser won't accept anything, but a data declarations
    rn_at (tydecl@TyData {tcdCtxt = L ctxtL ctxt, tcdLName = tycon, 
			  tcdTyPats = Just typats, tcdCons = condecls,
			  tcdDerivs = derivs}) =
      do { checkM (null ctxt    ) $ addErr atNoCtxt	-- no context
         ; checkM (null condecls) $ addErr atNoCons	-- no constructors
	 -- check and collect type parameters
         ; let (idxParms, excessParms) = splitAt (length classLTyVars) typats
	 ; zipWithM_ cmpTyVar idxParms classLTyVars
	 ; excessTyVars <- liftM catMaybes $ mappM chkTyVar excessParms
	 -- bind excess parameters
	 ; bindTyVarsRn data_doc excessTyVars	$ \ excessTyVars' -> do {
	 ; tycon' <- lookupLocatedTopBndrRn tycon
	 ; (derivs', deriv_fvs) <- rn_derivs derivs
	 ; returnM (TyData {tcdND = tcdND tydecl, tcdCtxt = L ctxtL [], 
			    tcdLName = tycon', 
			    tcdTyVars = classLTyVars ++ excessTyVars',
			    tcdTyPats = Nothing, tcdKindSig = Nothing, 
			    tcdCons = [], tcdDerivs = derivs'}, 
		    delFVs (map hsLTyVarName (classLTyVars ++ excessTyVars')) $
	     	    deriv_fvs) } }
      where
	    -- Check that the name space is correct!
	cmpTyVar (L l ty@(HsTyVar tv)) classTV =      -- just a type variable
	  checkM (rdrNameOcc tv == nameOccName classTVName) $ 
	    mustMatchErr l ty classTVName
          where
	    classTVName = hsLTyVarName classTV
	cmpTyVar (L l ty@(HsKindSig (L _ (HsTyVar tv)) k)) _ | isRdrTyVar tv = 
	  noKindSigErr l tv   -- additional kind sig not allowed at class parms
	cmpTyVar (L l otherTy) _ = 
	  tyVarExpectedErr l  -- parameter must be a type variable

	    -- Check that the name space is correct!
	chkTyVar (L l (HsKindSig (L _ (HsTyVar tv)) k))
	  | isRdrTyVar tv      = return $ Just (L l (KindedTyVar tv k))
	chkTyVar (L l (HsTyVar tv))
	  | isRdrTyVar tv      = return $ Just (L l (UserTyVar tv))
	chkTyVar (L l otherTy) = tyVarExpectedErr l >> return Nothing
				 -- drop parameter; we stop after renaming anyways

        rn_derivs Nothing   = returnM (Nothing, emptyFVs)
        rn_derivs (Just ds) = do
			        ds' <- rnLHsTypes data_doc ds
				returnM (Just ds', extractHsTyNames_s ds')
    
        atNoCtxt = text "Associated data type declarations cannot have a context"
        atNoCons = text "Associated data type declarations cannot have any constructors"
        data_doc = text "In the data type declaration for" <+> quotes (ppr tycon)

noKindSigErr l ty =
  addErrAt l $
    sep [ptext SLIT("No kind signature allowed at copies of class parameters:"),
         nest 2 $ ppr ty]

mustMatchErr l ty classTV =
  addErrAt l $
    sep [ptext SLIT("Type variable"), quotes (ppr ty), 
	 ptext SLIT("must match corresponding class parameter"), 
	 quotes (ppr classTV)]

tyVarExpectedErr l = 
  addErrAt l (ptext SLIT("Type found where type variable expected"))
817
\end{code}
818

819 820 821 822 823 824 825

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

826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844
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.

845 846 847
\begin{code}
rnSplice :: HsSplice RdrName -> RnM (HsSplice Name, FreeVars)
rnSplice (HsSplice n expr)
848 849 850 851 852 853 854 855 856 857 858 859 860
  = 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) }
861 862 863 864 865 866 867 868 869

#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   
870
\end{code}