TcRnDriver.lhs 34.8 KB
Newer Older
1
2
3
4
5
6
7
8
%
% (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
%
\section[TcModule]{Typechecking a whole module}

\begin{code}
module TcRnDriver (
#ifdef GHCI
9
	mkExportEnv, getModuleContents, tcRnStmt, tcRnThing, tcRnExpr,
10
#endif
11
12
	tcRnModule, 
	tcTopSrcDecls,
13
	tcRnIface, tcRnExtCore
14
15
16
17
    ) where

#include "HsVersions.h"

18
#ifdef GHCI
chak's avatar
chak committed
19
import {-# SOURCE #-} TcSplice ( tcSpliceDecls )
20
21
#endif

22
import CmdLineOpts	( DynFlag(..), opt_PprStyle_Debug, dopt )
23
import DriverState	( v_MainModIs, v_MainFunIs )
24
import HsSyn		( HsModule(..), HsBinds(..), MonoBinds(..), HsExpr(..),
25
26
			  HsGroup(..), SpliceDecl(..), HsExtCore(..),
			  andMonoBinds
27
			)
28
29
30
31
32
33
34
35
import RdrHsSyn		( RdrNameHsModule, RdrNameHsDecl, 
			  findSplice, main_RDR_Unqual )

import PrelNames	( runIOName, rootMainName, mAIN_Name )
import RdrName		( RdrName, mkRdrUnqual, emptyGlobalRdrEnv, 
			  plusGlobalRdrEnv )
import TcHsSyn		( zonkTopDecls )
import TcExpr 		( tcInferRho )
36
import TcRnMonad
37
38
import TcType		( tidyTopType )
import Inst		( showLIE )
39
40
import TcBinds		( tcTopBinds )
import TcDefaults	( tcDefaults )
41
import TcEnv		( tcExtendGlobalValEnv, tcLookupGlobal )
42
43
import TcRules		( tcRules )
import TcForeign	( tcForeignImports, tcForeignExports )
44
45
46
import TcInstDcls	( tcInstDecls1, tcInstDecls2 )
import TcIface		( typecheckIface, tcExtCoreBindings )
import TcSimplify	( tcSimplifyTop )
47
import TcTyClsDecls	( tcTyAndClassDecls )
48
import LoadIface	( loadOrphanModules )
49
import RnNames		( importsFromLocalDecls, rnImports, exportsFromAvail, 
50
			  reportUnusedNames )
51
52
import RnEnv		( lookupSrcOcc_maybe )
import RnSource		( rnSrcDecls, rnTyClDecls, checkModDeprec )
53
import PprCore		( pprIdRules, pprCoreBindings )
54
55
56
57
58
import CoreSyn		( IdCoreRule, bindersOfBinds )
import ErrUtils		( mkDumpDoc, showPass )
import Id		( mkLocalId, isLocalId, idName, idType, setIdLocalExported )
import Var		( Var )
import Module           ( mkHomeModule, mkModuleName, moduleName, moduleEnvElts )
59
import OccName		( mkVarOcc )
60
import Name		( Name, isExternalName, getSrcLoc, getOccName )
61
import NameSet
62
import TyCon		( tyConHasGenerics )
63
import Outputable
64
65
import HscTypes		( ModIface, ModDetails(..), ModGuts(..),
			  HscEnv(..), ModIface(..), ModDetails(..), 
66
			  GhciMode(..), noDependencies,
67
68
69
			  Deprecs( NoDeprecs ), plusDeprecs,
			  GenAvailInfo(Avail), availsToNameSet, availName,
			  ForeignStubs(NoStubs), TypeEnv, typeEnvTyCons, 
70
			  extendTypeEnvWithIds, typeEnvIds, typeEnvTyCons,
71
			  emptyFixityEnv
72
73
			)
#ifdef GHCI
74
75
76
77
78
79
80
81
82
83
84
import HsSyn		( HsStmtContext(..), 
			  Stmt(..), Pat(VarPat), 
			  collectStmtsBinders, mkSimpleMatch, placeHolderType )
import RdrHsSyn		( RdrNameHsExpr, RdrNameStmt )
import RdrName		( GlobalRdrEnv, mkGlobalRdrEnv, GlobalRdrElt(..),
			  Provenance(..), ImportSpec(..),
			  lookupLocalRdrEnv, extendLocalRdrEnv )
import RnHsSyn		( RenamedStmt ) 
import RnSource		( addTcgDUs )
import TcHsSyn		( TypecheckedHsExpr, mkHsLet, zonkTopExpr, zonkTopBndrs )
import TcExpr		( tcCheckRho )
85
86
import TcMType		( zonkTcType )
import TcMatches	( tcStmtsAndThen, TcStmtCtxt(..) )
87
88
89
90
91
import TcSimplify	( tcSimplifyInteractive, tcSimplifyInfer )
import TcType		( Type, mkForAllTys, mkFunTys, mkTyConApp, tyVarsOfType )
import TcEnv		( tcLookupTyCon, tcLookupId )
import TyCon		( DataConDetails(..) )
import Inst		( tcStdSyntaxName )
92
import RnExpr		( rnStmts, rnExpr )
93
94
95
96
97
98
99
100
import RnNames		( exportsToAvails )
import LoadIface	( loadSysInterface )
import IfaceSyn		( IfaceDecl(..), IfaceClassOp(..), IfaceConDecl(..), IfaceExtName(..),
			  tyThingToIfaceDecl )
import IfaceEnv		( tcIfaceGlobal )
import RnEnv		( lookupOccRn, dataTcOccs, lookupFixityRn )
import Id		( Id, isImplicitId )
import MkId		( unsafeCoerceId )
101
102
import TysWiredIn	( mkListTy, unitTy )
import IdInfo		( GlobalIdDetails(..) )
103
104
105
import SrcLoc		( interactiveSrcLoc )
import Var		( setGlobalIdDetails )
import Name		( nameOccName, nameModuleName )
106
import NameEnv		( delListFromNameEnv )
107
108
109
110
111
112
113
import PrelNames	( iNTERACTIVE, ioTyConName, printName, monadNames, itName, returnIOName )
import Module		( ModuleName, lookupModuleEnvByName )
import HscTypes		( InteractiveContext(..),
			  HomeModInfo(..), typeEnvElts, 
			  TyThing(..), availNames, icPrintUnqual )
import BasicTypes	( RecFlag(..), Fixity )
import Panic		( ghcError, GhcException(..) )
114
115
#endif

116
import FastString	( mkFastString )
117
118
119
120
121
122
123
124
125
126
127
128
129
import Util		( sortLt )
\end{code}



%************************************************************************
%*									*
	Typecheck and rename a module
%*									*
%************************************************************************


\begin{code}
130
tcRnModule :: HscEnv 
131
	   -> RdrNameHsModule 
132
	   -> IO (Maybe TcGblEnv)
133

134
tcRnModule hsc_env
135
	   (HsModule maybe_mod exports import_decls local_decls mod_deprec loc)
136
137
 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;

138
139
140
141
   let { this_mod = case maybe_mod of
			Nothing  -> mkHomeModule mAIN_Name	-- 'module M where' is omitted
			Just mod -> mod } ;			-- The normal case
		
142
   initTc hsc_env this_mod $ addSrcLoc loc $
143
144
145
   do { 	-- Deal with imports; sets tcg_rdr_env, tcg_imports
	(rdr_env, imports) <- rnImports import_decls ;
	updGblEnv ( \ gbl -> gbl { tcg_rdr_env = rdr_env,
146
				   tcg_imports = tcg_imports gbl `plusImportAvails` imports }) 
147
		     $ do {
148
	traceRn (text "rn1" <+> ppr (imp_dep_mods imports)) ;
149
150
151
152
153
		-- Fail if there are any errors so far
		-- The error printing (if needed) takes advantage 
		-- of the tcg_env we have now set
	failIfErrsM ;

154
155
156
157
		-- Load any orphan-module interfaces, so that
		-- their rules and instance decls will be found
	loadOrphanModules (imp_orphs imports) ;

158
159
	traceRn (text "rn1a") ;
		-- Rename and type check the declarations
160
	tcg_env <- tcRnSrcDecls local_decls ;
161
162
163
164
165
	setGblEnv tcg_env		$ do {

	traceRn (text "rn3") ;

		-- Process the export list
166
	export_avails <- exportsFromAvail maybe_mod exports ;
167

168
169
170
171
172
173
		-- Get any supporting decls for the exports that have not already
		-- been sucked in for the declarations in the body of the module.
		-- (This can happen if something is imported only to be re-exported.)
		--
		-- Importing these supporting declarations is required 
		--	*only* to gether usage information
174
		--	(see comments with MkIface.mkImportInfo for why)
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
		-- We don't need the results, but sucking them in may side-effect
		-- the ExternalPackageState, apart from recording usage
	mappM (tcLookupGlobal . availName) export_avails ;

		-- Check whether the entire module is deprecated
		-- This happens only once per module
	let { mod_deprecs = checkModDeprec mod_deprec } ;

		-- Add exports and deprecations to envt
	let { export_fvs = availsToNameSet export_avails ;
	      final_env  = tcg_env { tcg_exports = export_avails,
				     tcg_dus = tcg_dus tcg_env `plusDU` usesOnly export_fvs,
				     tcg_deprecs = tcg_deprecs tcg_env `plusDeprecs` 
						   mod_deprecs }
		-- A module deprecation over-rides the earlier ones
	     } ;
191
192

		-- Report unused names
193
 	reportUnusedNames final_env ;
194
195

		-- Dump output and return
196
197
198
	tcDump final_env ;
	return final_env
    }}}}
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
\end{code}


%*********************************************************
%*						 	 *
\subsection{Closing up the interface decls}
%*							 *
%*********************************************************

Suppose we discover we don't need to recompile.   Then we start from the
IfaceDecls in the ModIface, and fluff them up by sucking in all the decls they need.

\begin{code}
tcRnIface :: HscEnv
	  -> ModIface 	-- Get the decls from here
214
215
216
	  -> IO ModDetails
tcRnIface hsc_env iface
  = initIfaceIO hsc_env (typecheckIface iface)
217
218
219
220
221
222
223
224
225
226
\end{code}


%************************************************************************
%*									*
		The interactive interface 
%*									*
%************************************************************************

\begin{code}
227
#ifdef GHCI
228
tcRnStmt :: HscEnv
229
230
	 -> InteractiveContext
	 -> RdrNameStmt
231
	 -> IO (Maybe (InteractiveContext, [Name], TypecheckedHsExpr))
232
		-- The returned [Name] is the same as the input except for
233
		-- ExprStmt, in which case the returned [Name] is [itName]
234
235
236
		--
		-- The returned TypecheckedHsExpr is of type IO [ () ],
		-- a list of the bound values, coerced to ().
237

238
239
tcRnStmt hsc_env ictxt rdr_stmt
  = initTc hsc_env iNTERACTIVE $ 
240
241
242
    setInteractiveContext ictxt $ do {

    -- Rename; use CmdLineMode because tcRnStmt is only used interactively
243
    ([rn_stmt], fvs) <- rnStmts DoExpr [rdr_stmt] ;
244
245
246
247
    traceRn (text "tcRnStmt" <+> vcat [ppr rdr_stmt, ppr rn_stmt, ppr fvs]) ;
    failIfErrsM ;
    
    -- The real work is done here
248
    (bound_ids, tc_expr) <- tcUserStmt rn_stmt ;
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
    
    traceTc (text "tcs 1") ;
    let {	-- Make all the bound ids "global" ids, now that
    		-- they're notionally top-level bindings.  This is
	    	-- important: otherwise when we come to compile an expression
	    	-- using these ids later, the byte code generator will consider
	    	-- the occurrences to be free rather than global.
	global_ids     = map globaliseId bound_ids ;
	globaliseId id = setGlobalIdDetails id VanillaGlobal ;
    
		-- Update the interactive context
	rn_env   = ic_rn_local_env ictxt ;
	type_env = ic_type_env ictxt ;

	bound_names = map idName global_ids ;
	new_rn_env  = extendLocalRdrEnv rn_env bound_names ;

		-- Remove any shadowed bindings from the type_env;
		-- they are inaccessible but might, I suppose, cause 
		-- a space leak if we leave them there
	shadowed = [ n | name <- bound_names,
			 let rdr_name = mkRdrUnqual (nameOccName name),
271
			 Just n <- [lookupLocalRdrEnv rn_env rdr_name] ] ;
272
273
274
275
276
277
278
279
280
281
282
283
284

	filtered_type_env = delListFromNameEnv type_env shadowed ;
	new_type_env = extendTypeEnvWithIds filtered_type_env global_ids ;

	new_ic = ictxt { ic_rn_local_env = new_rn_env, 
		  	 ic_type_env     = new_type_env }
    } ;

    dumpOptTcRn Opt_D_dump_tc 
    	(vcat [text "Bound Ids" <+> pprWithCommas ppr global_ids,
    	       text "Typechecked expr" <+> ppr tc_expr]) ;

    returnM (new_ic, bound_names, tc_expr)
285
    }
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
\end{code}		


Here is the grand plan, implemented in tcUserStmt

	What you type			The IO [HValue] that hscStmt returns
	-------------			------------------------------------
	let pat = expr		==> 	let pat = expr in return [coerce HVal x, coerce HVal y, ...]
					bindings: [x,y,...]

	pat <- expr		==> 	expr >>= \ pat -> return [coerce HVal x, coerce HVal y, ...]
					bindings: [x,y,...]

	expr (of IO type)	==>	expr >>= \ v -> return [coerce HVal v]
	  [NB: result not printed]	bindings: [it]
	  
	expr (of non-IO type,	==>	let v = expr in print v >> return [coerce HVal v]
	  result showable)		bindings: [it]

	expr (of non-IO type, 
	  result not showable)	==>	error


\begin{code}
---------------------------
311
312
313
tcUserStmt :: RenamedStmt -> TcM ([Id], TypecheckedHsExpr)
tcUserStmt (ExprStmt expr _ loc)
  = newUnique 		`thenM` \ uniq ->
314
315
316
317
318
    let 
	fresh_it = itName uniq
        the_bind = FunMonoBind fresh_it False 
			[ mkSimpleMatch [] expr placeHolderType loc ] loc
    in
319
    tryTcLIE_ (do { 	-- Try this if the other fails
320
		traceTc (text "tcs 1b") ;
321
		tc_stmts [
322
323
324
325
326
		    LetStmt (MonoBind the_bind [] NonRecursive),
		    ExprStmt (HsApp (HsVar printName) (HsVar fresh_it)) 
			     placeHolderType loc] })
	  (do { 	-- Try this first 
		traceTc (text "tcs 1a") ;
327
		tc_stmts [BindStmt (VarPat fresh_it) expr loc] })
328

329
tcUserStmt stmt = tc_stmts [stmt]
330
331

---------------------------
332
tc_stmts stmts
333
 = do { ioTyCon <- tcLookupTyCon ioTyConName ;
334
	let {
335
336
337
338
	    ret_ty    = mkListTy unitTy ;
	    io_ret_ty = mkTyConApp ioTyCon [ret_ty] ;

	    names = collectStmtsBinders stmts ;
339
340
341
342
343

	    stmt_ctxt = SC { sc_what = DoExpr, 
			     sc_rhs  = check_rhs,
			     sc_body = check_body,
			     sc_ty   = ret_ty } ;
344

345
	    check_rhs rhs rhs_ty = tcCheckRho rhs  (mkTyConApp ioTyCon [rhs_ty]) ;
346
	    check_body body      = tcCheckRho body io_ret_ty ;
347

348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
		-- mk_return builds the expression
		--	returnIO @ [()] [coerce () x, ..,  coerce () z]
		--
		-- Despite the inconvenience of building the type applications etc,
		-- this *has* to be done in type-annotated post-typecheck form
		-- because we are going to return a list of *polymorphic* values
		-- coerced to type (). If we built a *source* stmt
		--	return [coerce x, ..., coerce z]
		-- then the type checker would instantiate x..z, and we wouldn't
		-- get their *polymorphic* values.  (And we'd get ambiguity errs
		-- if they were overloaded, since they aren't applied to anything.)
	    mk_return ret_id ids = HsApp (TyApp (HsVar ret_id) [ret_ty]) 
			      		 (ExplicitList unitTy (map mk_item ids)) ;
	    mk_item id = HsApp (TyApp (HsVar unsafeCoerceId) [idType id, unitTy])
		    	       (HsVar id) ;
363
364

	    io_ty = mkTyConApp ioTyCon []
365
	 } ;
366
367
368

	-- OK, we're ready to typecheck the stmts
	traceTc (text "tcs 2") ;
369
	((ids, tc_expr), lie) <- getLIE $ do {
370
	    (ids, tc_stmts) <- tcStmtsAndThen combine stmt_ctxt stmts	$ 
371
372
373
374
			do {
			    -- Look up the names right in the middle,
			    -- where they will all be in scope
			    ids <- mappM tcLookupId names ;
375
			    ret_id <- tcLookupId returnIOName ;		-- return @ IO
376
			    return (ids, [ResultStmt (mk_return ret_id ids) interactiveSrcLoc]) } ;
377

378
	    io_ids <- mappM (tcStdSyntaxName DoOrigin io_ty) monadNames ;
379
	    return (ids, HsDo DoExpr tc_stmts io_ids io_ret_ty interactiveSrcLoc) 
380
	} ;
381
382
383
384

	-- Simplify the context right here, so that we fail
	-- if there aren't enough instances.  Notably, when we see
	--		e
385
	-- we use recoverTc_ to try	it <- e
386
387
388
	-- and then			let it = e
	-- It's the simplify step that rejects the first.
	traceTc (text "tcs 3") ;
389
	const_binds <- tcSimplifyInteractive lie ;
390
391

	-- Build result expression and zonk it
392
	let { expr = mkHsLet const_binds tc_expr } ;
393
	zonked_expr <- zonkTopExpr expr ;
394
	zonked_ids  <- zonkTopBndrs ids ;
395
396
397
398
399
400
401
402
403
404
405

	return (zonked_ids, zonked_expr)
	}
  where
    combine stmt (ids, stmts) = (ids, stmt:stmts)
\end{code}


tcRnExpr just finds the type of an expression

\begin{code}
406
tcRnExpr :: HscEnv
407
408
	 -> InteractiveContext
	 -> RdrNameHsExpr
409
410
411
	 -> IO (Maybe Type)
tcRnExpr hsc_env ictxt rdr_expr
  = initTc hsc_env iNTERACTIVE $ 
412
413
    setInteractiveContext ictxt $ do {

414
    (rn_expr, fvs) <- rnExpr rdr_expr ;
415
416
417
418
    failIfErrsM ;

	-- Now typecheck the expression; 
	-- it might have a rank-2 type (e.g. :t runST)
419
    ((tc_expr, res_ty), lie)	   <- getLIE (tcInferRho rn_expr) ;
420
    ((qtvs, _, dict_ids), lie_top) <- getLIE (tcSimplifyInfer smpl_doc (tyVarsOfType res_ty) lie)  ;
421
    tcSimplifyInteractive lie_top ;
422
423
424
425
426

    let { all_expr_ty = mkForAllTys qtvs 		$
    		        mkFunTys (map idType dict_ids)	$
    		        res_ty } ;
    zonkTcType all_expr_ty
427
    }
428
429
430
431
432
433
  where
    smpl_doc = ptext SLIT("main expression")
\end{code}


\begin{code}
434
tcRnThing :: HscEnv
435
436
	  -> InteractiveContext
	  -> RdrName
437
	  -> IO (Maybe [(IfaceDecl, Fixity)])
438
-- Look up a RdrName and return all the TyThings it might be
439
440
441
442
-- A capitalised RdrName is given to us in the DataName namespace,
-- but we want to treat it as *both* a data constructor 
-- *and* as a type or class constructor; 
-- hence the call to dataTcOccs, and we return up to two results
443
444
tcRnThing hsc_env ictxt rdr_name
  = initTc hsc_env iNTERACTIVE $ 
445
446
447
448
449
450
451
    setInteractiveContext ictxt $ do {

	-- If the identifier is a constructor (begins with an
	-- upper-case letter), then we need to consider both
	-- constructor and type class identifiers.
    let { rdr_names = dataTcOccs rdr_name } ;

452
	-- results :: [(Messages, Maybe Name)]
453
    results <- mapM (tryTc . lookupOccRn) rdr_names ;
454
455
456
457
458
459
460

	-- The successful lookups will be (Just name)
    let { (warns_s, good_names) = unzip [ (msgs, name) 
					| (msgs, Just name) <- results] ;
	  errs_s = [msgs | (msgs, Nothing) <- results] } ;

	-- Fail if nothing good happened, else add warnings
461
462
463
464
465
466
    if null good_names then
		-- No lookup succeeded, so
		-- pick the first error message and report it
		-- ToDo: If one of the errors is "could be Foo.X or Baz.X",
		--	 while the other is "X is not in scope", 
		--	 we definitely want the former; but we might pick the latter
467
468
469
470
	do { addMessages (head errs_s) ; failM }
      else 			-- Add deprecation warnings
	mapM_ addMessages warns_s ;
	
471
	-- And lookup up the entities
472
473
474
475
476
477
478
479
480
481
482
483
484
485
    mapM do_one good_names
    }
  where
    do_one name = do { thing <- tcLookupGlobal name
		     ; fixity <- lookupFixityRn name
		     ; return (toIfaceDecl ictxt thing, fixity) }

toIfaceDecl :: InteractiveContext -> TyThing -> IfaceDecl
toIfaceDecl ictxt thing
  = tyThingToIfaceDecl True {- Discard IdInfo -} ext_nm thing
  where
    unqual = icPrintUnqual ictxt
    ext_nm n | unqual n  = LocalTop (nameOccName n)	-- What a hack
	     | otherwise = ExtPkg (nameModuleName n) (nameOccName n)
486
487
488
489
\end{code}


\begin{code}
490
setInteractiveContext :: InteractiveContext -> TcRn a -> TcRn a
491
492
setInteractiveContext icxt thing_inside 
  = traceTc (text "setIC" <+> ppr (ic_type_env icxt))	`thenM_`
493
494
495
496
    (updGblEnv (\env -> env {tcg_rdr_env  = ic_rn_gbl_env icxt,
			     tcg_type_env = ic_type_env   icxt}) $
     updLclEnv (\env -> env {tcl_rdr = ic_rn_local_env icxt})	$
	       thing_inside)
497
#endif /* GHCI */
498
499
500
501
502
503
504
505
506
\end{code}

%************************************************************************
%*									*
	Type-checking external-core modules
%*									*
%************************************************************************

\begin{code}
507
508
509
tcRnExtCore :: HscEnv 
	    -> HsExtCore RdrName
	    -> IO (Maybe ModGuts)
510
511
	-- Nothing => some error occurred 

512
513
tcRnExtCore hsc_env (HsExtCore this_mod decls src_binds)
	-- The decls are IfaceDecls; all names are original names
514
515
 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;

516
   initTc hsc_env this_mod $ do {
517

518
519
	-- Deal with the type declarations; first bring their stuff
	-- into scope, then rname them, then type check them
520
   (rdr_env, imports) <- importsFromLocalDecls (mkFakeGroup decls) ;
521

522
523
524
525
526
527
   updGblEnv (\gbl -> gbl { tcg_rdr_env = rdr_env `plusGlobalRdrEnv` tcg_rdr_env gbl,
			    tcg_imports = imports `plusImportAvails` tcg_imports gbl }) 
		  $ do {

   rn_decls <- rnTyClDecls decls ;
   failIfErrsM ;
528
529
530
531
532
533

	-- Dump trace of renaming part
   rnDump (ppr rn_decls) ;

	-- Typecheck them all together so that
	-- any mutually recursive types are done right
534
535
536
   tcg_env <- checkNoErrs (tcTyAndClassDecls rn_decls) ;
	-- Make the new type env available to stuff slurped from interface files

537
538
539
   setGblEnv tcg_env $ do {
   
	-- Now the core bindings
540
541
   core_binds <- initIfaceExtCore (tcExtCoreBindings this_mod src_binds) ;

542
543
	-- Wrap up
   let {
544
	bndrs 	   = bindersOfBinds core_binds ;
545
546
547
548
549
550
	my_exports = map (Avail . idName) bndrs ;
		-- ToDo: export the data types also?

	final_type_env = extendTypeEnvWithIds (tcg_type_env tcg_env) bndrs ;

	mod_guts = ModGuts {	mg_module   = this_mod,
551
552
				mg_usages   = [],		-- ToDo: compute usage
				mg_dir_imps = [],		-- ??
553
				mg_deps     = noDependencies,	-- ??
554
555
556
				mg_exports  = my_exports,
				mg_types    = final_type_env,
				mg_insts    = tcg_insts tcg_env,
557
558
				mg_rules    = [],
				mg_binds    = core_binds,
559
560
561
562
563
564
565
566
567
568
569
570

				-- Stubs
				mg_rdr_env  = emptyGlobalRdrEnv,
				mg_fix_env  = emptyFixityEnv,
				mg_deprecs  = NoDeprecs,
				mg_foreign  = NoStubs
		    } } ;

   tcCoreDump mod_guts ;

   return mod_guts
   }}}}
571
572
573
574
575
576

mkFakeGroup decls -- Rather clumsy; lots of unused fields
  = HsGroup {	hs_tyclds = decls, 	-- This is the one we want
		hs_valds = EmptyBinds, hs_fords = [],
		hs_instds = [], hs_fixds = [], hs_depds = [],
		hs_ruleds = [] }
577
578
579
580
581
582
583
584
585
\end{code}


%************************************************************************
%*									*
	Type-checking the top level of a module
%*									*
%************************************************************************

586
\begin{code}
587
tcRnSrcDecls :: [RdrNameHsDecl] -> TcM TcGblEnv
588
	-- Returns the variables free in the decls
589
	-- Reason: solely to report unused imports and bindings
590
tcRnSrcDecls decls
591
592
 = do {  	-- Do all the declarations
	(tc_envs, lie) <- getLIE (tc_rn_src_decls decls) ;
593
594
595
596
597
598
599
600

	     -- tcSimplifyTop deals with constant or ambiguous InstIds.  
	     -- How could there be ambiguous ones?  They can only arise if a
	     -- top-level decl falls under the monomorphism
	     -- restriction, and no subsequent decl instantiates its
	     -- type.  (Usually, ambiguous type variables are resolved
	     -- during the generalisation step.)
        traceTc (text "Tc8") ;
601
	inst_binds <- setEnvs tc_envs (tcSimplifyTop lie) ;
602
		-- Setting the global env exposes the instances to tcSimplifyTop
603
604
		-- Setting the local env exposes the local Ids to tcSimplifyTop, 
		-- so that we get better error messages (monomorphism restriction)
605
606
607
608
609
610
611
612
613
614
615

	    -- Backsubstitution.  This must be done last.
	    -- Even tcSimplifyTop may do some unification.
        traceTc (text "Tc9") ;
	let { (tcg_env, _) = tc_envs ;
	      TcGblEnv { tcg_type_env = type_env, tcg_binds = binds, 
		         tcg_rules = rules, tcg_fords = fords } = tcg_env } ;

	(bind_ids, binds', fords', rules') <- zonkTopDecls (binds `andMonoBinds` inst_binds)
							   rules fords ;

616
	let { final_type_env = extendTypeEnvWithIds type_env bind_ids } ;
617

618
619
620
621
622
623
	-- Make the new type env available to stuff slurped from interface files
	writeMutVar (tcg_type_env_var tcg_env) final_type_env ;

	return (tcg_env { tcg_type_env = final_type_env,
			  tcg_binds = binds', tcg_rules = rules', tcg_fords = fords' }) 
   }
624

625
626
627
tc_rn_src_decls :: [RdrNameHsDecl] -> TcM (TcGblEnv, TcLclEnv)
-- Loops around dealing with each top level inter-splice group 
-- in turn, until it's dealt with the entire module
628
tc_rn_src_decls ds
629
 = do { let { (first_group, group_tail) = findSplice ds } ;
630
		-- If ds is [] we get ([], Nothing)
631

632
	-- Type check the decls up to, but not including, the first splice
633
	tc_envs@(tcg_env,tcl_env) <- tcRnGroup first_group ;
634

635
636
637
638
	-- Bale out if errors; for example, error recovery when checking
	-- the RHS of 'main' can mean that 'main' is not in the envt for 
	-- the subsequent checkMain test
	failIfErrsM ;
639

640
641
	setEnvs tc_envs $

642
	-- If there is no splice, we're nearly done
643
	case group_tail of {
644
	   Nothing -> do { 	-- Last thing: check for `main'
645
646
			   tcg_env <- checkMain ;
			   return (tcg_env, tcl_env) 
647
648
649
		      } ;

	-- If there's a splice, we must carry on
650
	   Just (SpliceDecl splice_expr splice_loc, rest_ds) -> do {
651
652
653
#ifndef GHCI
	failWithTc (text "Can't do a top-level splice; need a bootstrapped compiler")
#else
654

655
	-- Rename the splice expression, and get its supporting decls
656
	(rn_splice_expr, splice_fvs) <- addSrcLoc splice_loc $
657
				 	rnExpr splice_expr ;
658
659
660
661
	-- Execute the splice
	spliced_decls <- tcSpliceDecls rn_splice_expr ;

	-- Glue them on the front of the remaining decls and loop
662
663
	setGblEnv (tcg_env `addTcgDUs` usesOnly splice_fvs) $
	tc_rn_src_decls (spliced_decls ++ rest_ds)
664
#endif /* GHCI */
665
    }}}
666
\end{code}
667
668
669
670
671
672
673
674


%************************************************************************
%*									*
	Type-checking the top level of a module
%*									*
%************************************************************************

675
tcRnGroup takes a bunch of top-level source-code declarations, and
676
677
678
679
680
681
682
683
684
685
686
 * renames them
 * gets supporting declarations from interface files
 * typechecks them
 * zonks them
 * and augments the TcGblEnv with the results

In Template Haskell it may be called repeatedly for each group of
declarations.  It expects there to be an incoming TcGblEnv in the
monad; it augments it and returns the new TcGblEnv.

\begin{code}
687
tcRnGroup :: HsGroup RdrName -> TcM (TcGblEnv, TcLclEnv)
688
	-- Returns the variables free in the decls, for unused-binding reporting
689
tcRnGroup decls
690
 = do {		-- Rename the declarations
691
	(tcg_env, rn_decls) <- rnTopSrcDecls decls ;
692
693
694
	setGblEnv tcg_env $ do {

		-- Typecheck the declarations
695
	tcTopSrcDecls rn_decls 
696
697
698
  }}

------------------------------------------------
699
rnTopSrcDecls :: HsGroup RdrName -> TcM (TcGblEnv, HsGroup Name)
700
701
702
rnTopSrcDecls group
 = do { 	-- Bring top level binders into scope
	(rdr_env, imports) <- importsFromLocalDecls group ;
703
704
705
	updGblEnv (\gbl -> gbl { tcg_rdr_env = rdr_env `plusGlobalRdrEnv` tcg_rdr_env gbl,
				 tcg_imports = imports `plusImportAvails` tcg_imports gbl }) 
		  $ do {
706

707
708
	failIfErrsM ;	-- No point in continuing if (say) we have duplicate declarations

709
		-- Rename the source decls
710
	(tcg_env, rn_decls) <- rnSrcDecls group ;
711
712
713
	failIfErrsM ;

		-- Dump trace of renaming part
714
	rnDump (ppr rn_decls) ;
715

716
717
	return (tcg_env, rn_decls)
   }}
718
719

------------------------------------------------
720
721
tcTopSrcDecls :: HsGroup Name -> TcM (TcGblEnv, TcLclEnv)
tcTopSrcDecls
722
723
724
725
726
727
	(HsGroup { hs_tyclds = tycl_decls, 
		   hs_instds = inst_decls,
		   hs_fords  = foreign_decls,
		   hs_defds  = default_decls,
		   hs_ruleds = rule_decls,
		   hs_valds  = val_binds })
728
 = do {		-- Type-check the type and class decls, and all imported decls
729
		-- The latter come in via tycl_decls
730
731
        traceTc (text "Tc2") ;

732
733
734
735
736
737
738
739
740
	tcg_env <- checkNoErrs (tcTyAndClassDecls tycl_decls) ;
	-- tcTyAndClassDecls recovers internally, but if anything gave rise to
	-- an error we'd better stop now, to avoid a cascade
	
	-- Make these type and class decls available to stuff slurped from interface files
	writeMutVar (tcg_type_env_var tcg_env) (tcg_type_env tcg_env) ;


	setGblEnv tcg_env	$ do {
741
742
743
		-- Source-language instances, including derivings,
		-- and import the supporting declarations
        traceTc (text "Tc3") ;
744
	(tcg_env, inst_infos, deriv_binds) <- tcInstDecls1 tycl_decls inst_decls ;
745
746
747
748
749
	setGblEnv tcg_env	$ do {

	        -- Foreign import declarations next.  No zonking necessary
		-- here; we can tuck them straight into the global environment.
        traceTc (text "Tc4") ;
750
	(fi_ids, fi_decls) <- tcForeignImports foreign_decls ;
751
	tcExtendGlobalValEnv fi_ids	$ do {
752
753
754

		-- Default declarations
        traceTc (text "Tc4a") ;
755
	default_tys <- tcDefaults default_decls ;
756
757
758
759
	updGblEnv (\gbl -> gbl { tcg_default = default_tys }) $ do {
	
		-- Value declarations next
		-- We also typecheck any extra binds that came out 
760
		-- of the "deriving" process (deriv_binds)
761
762
763
764
765
766
        traceTc (text "Tc5") ;
	(tc_val_binds, lcl_env) <- tcTopBinds (val_binds `ThenBinds` deriv_binds) ;
	setLclTypeEnv lcl_env 	$ do {

	     	-- Second pass over class and instance declarations, 
        traceTc (text "Tc6") ;
767
	(tcl_env, inst_binds) <- tcInstDecls2 tycl_decls inst_infos ;
768
	showLIE (text "after instDecls2") ;
769
770
771
772

		-- Foreign exports
		-- They need to be zonked, so we return them
        traceTc (text "Tc7") ;
773
	(foe_binds, foe_decls) <- tcForeignExports foreign_decls ;
774
775
776
777
778

		-- Rules
	rules <- tcRules rule_decls ;

		-- Wrap up
779
        traceTc (text "Tc7a") ;
780
781
782
	tcg_env <- getGblEnv ;
	let { all_binds = tc_val_binds	 `AndMonoBinds`
			  inst_binds	 `AndMonoBinds`
783
			  foe_binds  ;
784

785
786
787
		-- Extend the GblEnv with the (as yet un-zonked) 
		-- bindings, rules, foreign decls
	      tcg_env' = tcg_env {  tcg_binds = tcg_binds tcg_env `andMonoBinds` all_binds,
788
789
				    tcg_rules = tcg_rules tcg_env ++ rules,
				    tcg_fords = tcg_fords tcg_env ++ foe_decls ++ fi_decls } } ;
790
  	return (tcg_env', lcl_env)
791
    }}}}}}
792
793
794
795
796
797
798
799
800
801
802
803
804
805
\end{code}


%*********************************************************
%*						 	 *
	mkGlobalContext: make up an interactive context

	Used for initialising the lexical environment
	of the interactive read-eval-print loop
%*							 *
%*********************************************************

\begin{code}
#ifdef GHCI
806
807
mkExportEnv :: HscEnv -> [ModuleName]	-- Expose these modules' exports only
 	    -> IO GlobalRdrEnv
808

809
810
mkExportEnv hsc_env exports
  = initIfaceIO hsc_env $ do {
811
    export_envs <- mappM getModuleExports exports ;
812
    returnM (foldr plusGlobalRdrEnv emptyGlobalRdrEnv export_envs)
813
814
    }

815
getModuleExports :: ModuleName -> IfG GlobalRdrEnv
816
getModuleExports mod 
817
818
819
820
821
822
823
824
825
826
827
  = do	{ iface <- load_iface mod
	; avails <- exportsToAvails (mi_exports iface)
	; let { gres = [ GRE  { gre_name = name, gre_prov = vanillaProv mod,
				gre_deprec = mi_dep_fn iface name }
			| avail <- avails, name <- availNames avail ] }
	; returnM (mkGlobalRdrEnv gres) }

vanillaProv :: ModuleName -> Provenance
-- We're building a GlobalRdrEnv as if the user imported
-- all the specified modules into the global interactive module
vanillaProv mod = Imported [ImportSpec mod mod False interactiveSrcLoc] False
828
829
830
831
832
\end{code}

\begin{code}
getModuleContents
  :: HscEnv
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
  -> InteractiveContext
  -> ModuleName			-- Module to inspect
  -> Bool			-- Grab just the exports, or the whole toplev
  -> IO [IfaceDecl]

getModuleContents hsc_env ictxt mod exports_only
 = initIfaceIO hsc_env (get_mod_contents exports_only)
 where
   get_mod_contents exports_only
      | not exports_only	-- We want the whole top-level type env
 			  -- so it had better be a home module
      = do { hpt <- getHpt
 	   ; case lookupModuleEnvByName hpt mod of
 	       Just mod_info -> return (map (toIfaceDecl ictxt) $
					filter wantToSee $
 				        typeEnvElts $
 				        md_types (hm_details mod_info))
 	       Nothing -> ghcError (ProgramError (showSDoc (noRdrEnvErr mod)))
 			  -- This is a system error; the module should be in the HPT
 	   }
  
      | otherwise		-- Want the exports only
      = do { iface <- load_iface mod
 	   ; avails <- exportsToAvails (mi_exports iface)
 	   ; mappM get_decl avails
    	}

   get_decl avail 
	= do { thing <- tcIfaceGlobal (availName avail)
	     ; return (filter_decl (availOccs avail) (toIfaceDecl ictxt thing)) }

---------------------
filter_decl occs decl@(IfaceClass {ifSigs = sigs})
  = decl { ifSigs = filter (keep_sig occs) sigs }
filter_decl occs decl@(IfaceData {ifCons = DataCons cons})
  = decl { ifCons = DataCons (filter (keep_con occs) cons) }
filter_decl occs decl
  = decl

keep_sig occs (IfaceClassOp occ _ _)	   = occ `elem` occs
keep_con occs (IfaceConDecl occ _ _ _ _ _) = occ `elem` occs

availOccs avail = map nameOccName (availNames avail)

wantToSee (AnId id)    = not (isImplicitId id)
wantToSee (ADataCon _) = False	-- They'll come via their TyCon
wantToSee _ 	       = True

---------------------
load_iface mod = loadSysInterface (text "context for compiling statements") mod

---------------------
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
noRdrEnvErr mod = ptext SLIT("No top-level environment available for module") 
		  <+> quotes (ppr mod)
#endif
\end{code}

%************************************************************************
%*									*
	Checking for 'main'
%*									*
%************************************************************************

\begin{code}
checkMain 
  = do { ghci_mode <- getGhciMode ;
	 tcg_env   <- getGblEnv ;
900
901
902
903
904
905
906
907
908
909
910

	 mb_main_mod <- readMutVar v_MainModIs ;
	 mb_main_fn  <- readMutVar v_MainFunIs ;
	 let { main_mod = case mb_main_mod of {
				Just mod -> mkModuleName mod ;
				Nothing  -> mAIN_Name } ;
	        main_fn  = case mb_main_fn of {
				Just fn -> mkRdrUnqual (mkVarOcc (mkFastString fn)) ;
				Nothing -> main_RDR_Unqual } } ;
	
	 check_main ghci_mode tcg_env main_mod main_fn
911
912
    }

913
914

check_main ghci_mode tcg_env main_mod main_fn
915
     -- If we are in module Main, check that 'main' is defined.
916
     -- It may be imported from another module!
917
918
919
920
921
922
     --
     -- ToDo: We have to return the main_name separately, because it's a
     -- bona fide 'use', and should be recorded as such, but the others
     -- aren't 
     -- 
     -- Blimey: a whole page of code to do this...
923
 | mod_name /= main_mod
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
 = return tcg_env

 | otherwise
 = addErrCtxt mainCtxt			$
   do	{ mb_main <- lookupSrcOcc_maybe main_fn
		-- Check that 'main' is in scope
		-- It might be imported from another module!
	; case mb_main of {
	     Nothing -> do { complain_no_main	
			   ; return tcg_env } ;
	     Just main_name -> do
	{ let { rhs = HsApp (HsVar runIOName) (HsVar main_name) }
		   	-- :Main.main :: IO () = runIO main 

	; (main_expr, ty) <- addSrcLoc (getSrcLoc main_name)	$
			     tcInferRho rhs

	; let { root_main_id = setIdLocalExported (mkLocalId rootMainName ty) ;
	        main_bind    = VarMonoBind root_main_id main_expr }

	; return (tcg_env { tcg_binds = tcg_binds tcg_env 
					`andMonoBinds` main_bind,
			    tcg_dus   = tcg_dus tcg_env
				        `plusDU` usesOnly (unitFV main_name)
		 }) 
    }}}
950
951
952
953
  where
    mod_name = moduleName (tcg_mod tcg_env) 
 
    complain_no_main | ghci_mode == Interactive = return ()
954
		     | otherwise 		= failWithTc noMainMsg
955
	-- In interactive mode, don't worry about the absence of 'main'
956
957
	-- In other modes, fail altogether, so that we don't go on
	-- and complain a second time when processing the export list.
958

959
960
961
    mainCtxt  = ptext SLIT("When checking the type of the main function") <+> quotes (ppr main_fn)
    noMainMsg = ptext SLIT("The main function") <+> quotes (ppr main_fn) 
		<+> ptext SLIT("is not defined in module") <+> quotes (ppr main_mod)
962
963
964
965
966
967
968
969
970
971
\end{code}


%************************************************************************
%*									*
		Degugging output
%*									*
%************************************************************************

\begin{code}
972
rnDump :: SDoc -> TcRn ()
973
-- Dump, with a banner, if -ddump-rn
974
rnDump doc = do { dumpOptTcRn Opt_D_dump_rn (mkDumpDoc "Renamer" doc) }
975

976
tcDump :: TcGblEnv -> TcRn ()
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
tcDump env
 = do { dflags <- getDOpts ;

	-- Dump short output if -ddump-types or -ddump-tc
	ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
	    (dumpTcRn short_dump) ;

	-- Dump bindings if -ddump-tc
	dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump)
   }
  where
    short_dump = pprTcGblEnv env
    full_dump  = ppr (tcg_binds env)
	-- NB: foreign x-d's have undefined's in their types; 
	--     hence can't show the tc_fords

tcCoreDump mod_guts
 = do { dflags <- getDOpts ;
	ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
 	    (dumpTcRn (pprModGuts mod_guts)) ;

	-- Dump bindings if -ddump-tc
	dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump) }
  where
    full_dump = pprCoreBindings (mg_binds mod_guts)

-- It's unpleasant having both pprModGuts and pprModDetails here
pprTcGblEnv :: TcGblEnv -> SDoc
pprTcGblEnv (TcGblEnv { tcg_type_env = type_env, 
		        tcg_insts    = dfun_ids, 
1007
1008
		        tcg_rules    = rules,
			tcg_imports  = imports })
1009
1010
1011
  = vcat [ ppr_types dfun_ids type_env
	 , ppr_insts dfun_ids
	 , vcat (map ppr rules)
1012
	 , ppr_gen_tycons (typeEnvTyCons type_env)
1013
1014
	 , ptext SLIT("Dependent modules:") <+> ppr (moduleEnvElts (imp_dep_mods imports))
	 , ptext SLIT("Dependent packages:") <+> ppr (imp_dep_pkgs imports)]
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042

pprModGuts :: ModGuts -> SDoc
pprModGuts (ModGuts { mg_types = type_env,
		      mg_rules = rules })
  = vcat [ ppr_types [] type_env,
	   ppr_rules rules ]


ppr_types :: [Var] -> TypeEnv -> SDoc
ppr_types dfun_ids type_env
  = text "TYPE SIGNATURES" $$ nest 4 (ppr_sigs ids)
  where
    ids = [id | id <- typeEnvIds type_env, want_sig id]
    want_sig id | opt_PprStyle_Debug = True
	        | otherwise	     = isLocalId id && 
				       isExternalName (idName id) && 
				       not (id `elem` dfun_ids)
	-- isLocalId ignores data constructors, records selectors etc.
	-- The isExternalName ignores local dictionary and method bindings
	-- that the type checker has invented.  Top-level user-defined things 
	-- have External names.

ppr_insts :: [Var] -> SDoc
ppr_insts []       = empty
ppr_insts dfun_ids = text "INSTANCES" $$ nest 4 (ppr_sigs dfun_ids)

ppr_sigs :: [Var] -> SDoc
ppr_sigs ids
1043
1044
	-- Print type signatures; sort by OccName 
  = vcat (map ppr_sig (sortLt lt_sig ids))
1045
  where
1046
1047
    lt_sig id1 id2 = getOccName id1 < getOccName id2
    ppr_sig id = ppr id <+> dcolon <+> ppr (tidyTopType (idType id))
1048
1049
1050
1051
1052
1053
1054
1055

ppr_rules :: [IdCoreRule] -> SDoc
ppr_rules [] = empty
ppr_rules rs = vcat [ptext SLIT("{-# RULES"),
		      nest 4 (pprIdRules rs),
		      ptext SLIT("#-}")]

ppr_gen_tycons []  = empty
1056
1057
ppr_gen_tycons tcs = vcat [ptext SLIT("Tycons with generics:"),
			   nest 2 (fsep (map ppr (filter tyConHasGenerics tcs)))]
1058
\end{code}