2 % (c) The GRASP/AQUA Project, Glasgow University, 1992-1998
4 \section[TcModule]{Typechecking a whole module}
9 mkGlobalContext, getModuleContents, tcRnStmt, tcRnThing, tcRnExpr,
11 tcRnModule, checkOldIface,
12 importSupportingDecls, tcTopSrcDecls,
13 tcRnIface, tcRnExtCore
16 #include "HsVersions.h"
19 import {-# SOURCE #-} TcSplice ( tcSpliceDecls )
20 import DsMeta ( templateHaskellNames )
23 import CmdLineOpts ( DynFlag(..), opt_PprStyle_Debug, dopt )
24 import DriverState ( v_MainModIs, v_MainFunIs )
25 import HsSyn ( HsModule(..), HsBinds(..), MonoBinds(..), HsExpr(..),
26 Stmt(..), Pat(VarPat), HsStmtContext(..), RuleDecl(..),
27 HsGroup(..), SpliceDecl(..),
28 mkSimpleMatch, placeHolderType, toHsType, andMonoBinds,
29 isSrcRule, collectStmtsBinders
31 import RdrHsSyn ( RdrNameHsModule, RdrNameHsDecl, RdrNameStmt, RdrNameHsExpr,
32 emptyGroup, mkGroup, findSplice, addImpDecls, main_RDR_Unqual )
34 import PrelNames ( iNTERACTIVE, ioTyConName, printName, monadNames,
35 returnIOName, runIOName,
36 rootMainName, itName, mAIN_Name
38 import RdrName ( RdrName, getRdrName, mkRdrUnqual,
39 lookupRdrEnv, elemRdrEnv )
41 import RnHsSyn ( RenamedStmt, RenamedTyClDecl,
42 ruleDeclFVs, instDeclFVs, tyClDeclFVs )
43 import TcHsSyn ( TypecheckedHsExpr, TypecheckedRuleDecl,
44 zonkTopDecls, mkHsLet,
45 zonkTopExpr, zonkTopBndrs
48 import TcExpr ( tcInferRho, tcCheckRho )
51 tyVarsOfType, tcFunResultTy, tidyTopType,
52 mkForAllTys, mkFunTys, mkTyConApp, tcSplitForAllTys
54 import Inst ( showLIE, tcStdSyntaxName )
55 import MkId ( unsafeCoerceId )
56 import TcBinds ( tcTopBinds )
57 import TcClassDcl ( tcClassDecls2 )
58 import TcDefaults ( tcDefaults )
59 import TcEnv ( tcExtendGlobalValEnv,
60 tcExtendInstEnv, tcExtendRules,
61 tcLookupTyCon, tcLookupGlobal,
64 import TcRules ( tcRules )
65 import TcForeign ( tcForeignImports, tcForeignExports )
66 import TcIfaceSig ( tcInterfaceSigs, tcCoreBinds )
67 import TcInstDcls ( tcInstDecls1, tcIfaceInstDecls, tcInstDecls2 )
68 import TcSimplify ( tcSimplifyTop, tcSimplifyInteractive, tcSimplifyInfer )
69 import TcTyClsDecls ( tcTyAndClassDecls )
71 import RnNames ( importsFromLocalDecls, rnImports, exportsFromAvail,
73 import RnIfaces ( slurpImpDecls, checkVersions, RecompileRequired, outOfDate )
74 import RnHiFiles ( readIface, loadOldIface )
75 import RnEnv ( lookupSrcName, lookupOccRn, plusGlobalRdrEnv,
76 ubiquitousNames, implicitModuleFVs, implicitStmtFVs, dataTcOccs )
77 import RnSource ( rnSrcDecls, checkModDeprec, rnStats )
79 import CoreUnfold ( unfoldingTemplate )
80 import CoreSyn ( IdCoreRule, Bind(..) )
81 import PprCore ( pprIdRules, pprCoreBindings )
82 import ErrUtils ( mkDumpDoc, showPass, pprBagOfErrors )
83 import Id ( Id, mkLocalId, isLocalId, idName, idType, idUnfolding, setIdLocalExported )
84 import Var ( Var, setGlobalIdDetails )
85 import Module ( Module, mkHomeModule, mkModuleName, moduleName, moduleUserString, moduleEnvElts )
86 import OccName ( mkVarOcc )
87 import Name ( Name, isExternalName, getSrcLoc, nameOccName )
89 import TyCon ( tyConGenInfo )
90 import BasicTypes ( EP(..), RecFlag(..) )
92 import HscTypes ( PersistentCompilerState(..), InteractiveContext(..),
93 ModIface, ModDetails(..), ModGuts(..),
95 ModIface(..), ModDetails(..), IfaceDecls(..),
96 GhciMode(..), noDependencies,
97 Deprecations(..), plusDeprecs,
99 GenAvailInfo(Avail), availsToNameSet,
101 TypeEnv, TyThing, typeEnvTyCons,
102 extendTypeEnvWithIds, typeEnvIds, typeEnvTyCons,
103 extendLocalRdrEnv, emptyFixityEnv
106 import TcMType ( zonkTcType )
107 import TcMatches ( tcStmtsAndThen, TcStmtCtxt(..) )
108 import RdrName ( rdrEnvElts )
109 import RnExpr ( rnStmts, rnExpr )
110 import RnHiFiles ( loadInterface )
111 import RnEnv ( mkGlobalRdrEnv )
112 import TysWiredIn ( mkListTy, unitTy )
113 import IdInfo ( GlobalIdDetails(..) )
114 import SrcLoc ( noSrcLoc )
115 import NameEnv ( delListFromNameEnv )
116 import HscTypes ( GlobalRdrElt(..), GlobalRdrEnv, ImportReason(..), Provenance(..),
120 import FastString ( mkFastString )
121 import Panic ( showException )
122 import List ( partition )
123 import Util ( sortLt )
128 %************************************************************************
130 Typecheck and rename a module
132 %************************************************************************
136 tcRnModule :: HscEnv -> PersistentCompilerState
138 -> IO (PersistentCompilerState, Maybe TcGblEnv)
140 tcRnModule hsc_env pcs
141 (HsModule maybe_mod exports import_decls local_decls mod_deprec loc)
142 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
144 let { this_mod = case maybe_mod of
145 Nothing -> mkHomeModule mAIN_Name -- 'module M where' is omitted
146 Just mod -> mod } ; -- The normal case
148 initTc hsc_env pcs this_mod $ addSrcLoc loc $
149 do { -- Deal with imports; sets tcg_rdr_env, tcg_imports
150 (rdr_env, imports) <- rnImports import_decls ;
151 updGblEnv ( \ gbl -> gbl { tcg_rdr_env = rdr_env,
152 tcg_imports = tcg_imports gbl `plusImportAvails` imports })
154 traceRn (text "rn1" <+> ppr (imp_dep_mods imports)) ;
155 -- Fail if there are any errors so far
156 -- The error printing (if needed) takes advantage
157 -- of the tcg_env we have now set
160 traceRn (text "rn1a") ;
161 -- Rename and type check the declarations
162 (tcg_env, src_dus) <- tcRnSrcDecls local_decls ;
163 setGblEnv tcg_env $ do {
165 traceRn (text "rn3") ;
166 -- Check whether the entire module is deprecated
167 -- This happens only once per module
168 -- Returns the full new deprecations; a module deprecation
169 -- over-rides the earlier ones
170 let { mod_deprecs = checkModDeprec mod_deprec } ;
171 updGblEnv (\gbl -> gbl { tcg_deprecs = tcg_deprecs gbl `plusDeprecs` mod_deprecs })
174 -- Process the export list
175 export_avails <- exportsFromAvail maybe_mod exports ;
176 updGblEnv (\gbl -> gbl { tcg_exports = export_avails })
179 -- Get any supporting decls for the exports that have not already
180 -- been sucked in for the declarations in the body of the module.
181 -- (This can happen if something is imported only to be re-exported.)
183 -- Importing these supporting declarations is required
184 -- *only* to gether usage information
185 -- (see comments with MkIface.mkImportInfo for why)
186 -- For OneShot compilation we could just throw away the decls
187 -- but for Batch or Interactive we must put them in the type
188 -- envt because they've been removed from the holding pen
189 let { export_fvs = availsToNameSet export_avails } ;
190 tcg_env <- importSupportingDecls export_fvs ;
191 setGblEnv tcg_env $ do {
193 -- Report unused names
194 let { all_dus = src_dus `plusDU` usesOnly export_fvs } ;
195 reportUnusedNames tcg_env all_dus ;
197 -- Dump output and return
204 %*********************************************************
206 \subsection{Closing up the interface decls}
208 %*********************************************************
210 Suppose we discover we don't need to recompile. Then we start from the
211 IfaceDecls in the ModIface, and fluff them up by sucking in all the decls they need.
215 -> PersistentCompilerState
216 -> ModIface -- Get the decls from here
217 -> IO (PersistentCompilerState, Maybe ModDetails)
218 -- Nothing <=> errors happened
219 tcRnIface hsc_env pcs
220 (ModIface {mi_module = mod, mi_decls = iface_decls})
221 = initTc hsc_env pcs mod $ do {
223 -- Get the supporting decls, and typecheck them all together
224 -- so that any mutually recursive types are done right
225 extra_decls <- slurpImpDecls needed ;
226 env <- typecheckIfaceDecls (group `addImpDecls` extra_decls) ;
228 returnM (ModDetails { md_types = tcg_type_env env,
229 md_insts = tcg_insts env,
230 md_rules = hsCoreRules (tcg_rules env)
231 -- All the rules from an interface are of the IfaceRuleOut form
234 rule_decls = dcl_rules iface_decls
235 inst_decls = dcl_insts iface_decls
236 tycl_decls = dcl_tycl iface_decls
237 group = emptyGroup { hs_ruleds = rule_decls,
238 hs_instds = inst_decls,
239 hs_tyclds = tycl_decls }
240 needed = unionManyNameSets (map ruleDeclFVs rule_decls) `unionNameSets`
241 unionManyNameSets (map instDeclFVs inst_decls) `unionNameSets`
242 unionManyNameSets (map tyClDeclFVs tycl_decls) `unionNameSets`
244 -- Data type decls with record selectors,
245 -- which may appear in the decls, need unpackCString
246 -- and friends. It's easier to just grab them right now.
248 hsCoreRules :: [TypecheckedRuleDecl] -> [IdCoreRule]
249 -- All post-typechecking Iface rules have the form IfaceRuleOut
250 hsCoreRules rules = [(id,rule) | IfaceRuleOut id rule <- rules]
254 %************************************************************************
256 The interactive interface
258 %************************************************************************
262 tcRnStmt :: HscEnv -> PersistentCompilerState
263 -> InteractiveContext
265 -> IO (PersistentCompilerState,
266 Maybe (InteractiveContext, [Name], TypecheckedHsExpr))
267 -- The returned [Name] is the same as the input except for
268 -- ExprStmt, in which case the returned [Name] is [itName]
270 -- The returned TypecheckedHsExpr is of type IO [ () ],
271 -- a list of the bound values, coerced to ().
273 tcRnStmt hsc_env pcs ictxt rdr_stmt
274 = initTc hsc_env pcs iNTERACTIVE $
275 setInteractiveContext ictxt $ do {
277 -- Rename; use CmdLineMode because tcRnStmt is only used interactively
278 ([rn_stmt], fvs) <- initRnInteractive ictxt
279 (rnStmts DoExpr [rdr_stmt]) ;
280 traceRn (text "tcRnStmt" <+> vcat [ppr rdr_stmt, ppr rn_stmt, ppr fvs]) ;
283 -- Suck in the supporting declarations and typecheck them
284 tcg_env <- importSupportingDecls (fvs `plusFV` implicitStmtFVs fvs) ;
285 -- NB: an earlier version deleted (rdrEnvElts local_env) from
286 -- the fvs. But (a) that isn't necessary, because previously
287 -- bound things in the local_env will be in the TypeEnv, and
288 -- the renamer doesn't re-slurp such things, and
289 -- (b) it's WRONG to delete them. Consider in GHCi:
290 -- Mod> let x = e :: T
291 -- Mod> let y = x + 3
292 -- We need to pass 'x' among the fvs to slurpImpDecls, so that
293 -- the latter can see that T is a gate, and hence import the Num T
294 -- instance decl. (See the InTypEnv case in RnIfaces.slurpSourceRefs.)
295 setGblEnv tcg_env $ do {
297 -- The real work is done here
298 (bound_ids, tc_expr) <- tcUserStmt rn_stmt ;
300 traceTc (text "tcs 1") ;
301 let { -- Make all the bound ids "global" ids, now that
302 -- they're notionally top-level bindings. This is
303 -- important: otherwise when we come to compile an expression
304 -- using these ids later, the byte code generator will consider
305 -- the occurrences to be free rather than global.
306 global_ids = map globaliseId bound_ids ;
307 globaliseId id = setGlobalIdDetails id VanillaGlobal ;
309 -- Update the interactive context
310 rn_env = ic_rn_local_env ictxt ;
311 type_env = ic_type_env ictxt ;
313 bound_names = map idName global_ids ;
314 new_rn_env = extendLocalRdrEnv rn_env bound_names ;
316 -- Remove any shadowed bindings from the type_env;
317 -- they are inaccessible but might, I suppose, cause
318 -- a space leak if we leave them there
319 shadowed = [ n | name <- bound_names,
320 let rdr_name = mkRdrUnqual (nameOccName name),
321 Just n <- [lookupRdrEnv rn_env rdr_name] ] ;
323 filtered_type_env = delListFromNameEnv type_env shadowed ;
324 new_type_env = extendTypeEnvWithIds filtered_type_env global_ids ;
326 new_ic = ictxt { ic_rn_local_env = new_rn_env,
327 ic_type_env = new_type_env }
330 dumpOptTcRn Opt_D_dump_tc
331 (vcat [text "Bound Ids" <+> pprWithCommas ppr global_ids,
332 text "Typechecked expr" <+> ppr tc_expr]) ;
334 returnM (new_ic, bound_names, tc_expr)
339 Here is the grand plan, implemented in tcUserStmt
341 What you type The IO [HValue] that hscStmt returns
342 ------------- ------------------------------------
343 let pat = expr ==> let pat = expr in return [coerce HVal x, coerce HVal y, ...]
346 pat <- expr ==> expr >>= \ pat -> return [coerce HVal x, coerce HVal y, ...]
349 expr (of IO type) ==> expr >>= \ v -> return [coerce HVal v]
350 [NB: result not printed] bindings: [it]
352 expr (of non-IO type, ==> let v = expr in print v >> return [coerce HVal v]
353 result showable) bindings: [it]
355 expr (of non-IO type,
356 result not showable) ==> error
360 ---------------------------
361 tcUserStmt :: RenamedStmt -> TcM ([Id], TypecheckedHsExpr)
362 tcUserStmt (ExprStmt expr _ loc)
363 = newUnique `thenM` \ uniq ->
365 fresh_it = itName uniq
366 the_bind = FunMonoBind fresh_it False
367 [ mkSimpleMatch [] expr placeHolderType loc ] loc
369 tryTcLIE_ (do { -- Try this if the other fails
370 traceTc (text "tcs 1b") ;
372 LetStmt (MonoBind the_bind [] NonRecursive),
373 ExprStmt (HsApp (HsVar printName) (HsVar fresh_it))
374 placeHolderType loc] })
375 (do { -- Try this first
376 traceTc (text "tcs 1a") ;
377 tc_stmts [BindStmt (VarPat fresh_it) expr loc] })
379 tcUserStmt stmt = tc_stmts [stmt]
381 ---------------------------
383 = do { ioTyCon <- tcLookupTyCon ioTyConName ;
385 ret_ty = mkListTy unitTy ;
386 io_ret_ty = mkTyConApp ioTyCon [ret_ty] ;
388 names = collectStmtsBinders stmts ;
390 stmt_ctxt = SC { sc_what = DoExpr,
392 sc_body = check_body,
395 check_rhs rhs rhs_ty = tcCheckRho rhs (mkTyConApp ioTyCon [rhs_ty]) ;
396 check_body body = tcCheckRho body io_ret_ty ;
398 -- mk_return builds the expression
399 -- returnIO @ [()] [coerce () x, .., coerce () z]
401 -- Despite the inconvenience of building the type applications etc,
402 -- this *has* to be done in type-annotated post-typecheck form
403 -- because we are going to return a list of *polymorphic* values
404 -- coerced to type (). If we built a *source* stmt
405 -- return [coerce x, ..., coerce z]
406 -- then the type checker would instantiate x..z, and we wouldn't
407 -- get their *polymorphic* values. (And we'd get ambiguity errs
408 -- if they were overloaded, since they aren't applied to anything.)
409 mk_return ret_id ids = HsApp (TyApp (HsVar ret_id) [ret_ty])
410 (ExplicitList unitTy (map mk_item ids)) ;
411 mk_item id = HsApp (TyApp (HsVar unsafeCoerceId) [idType id, unitTy])
414 io_ty = mkTyConApp ioTyCon []
417 -- OK, we're ready to typecheck the stmts
418 traceTc (text "tcs 2") ;
419 ((ids, tc_expr), lie) <- getLIE $ do {
420 (ids, tc_stmts) <- tcStmtsAndThen combine stmt_ctxt stmts $
422 -- Look up the names right in the middle,
423 -- where they will all be in scope
424 ids <- mappM tcLookupId names ;
425 ret_id <- tcLookupId returnIOName ; -- return @ IO
426 return (ids, [ResultStmt (mk_return ret_id ids) noSrcLoc]) } ;
428 io_ids <- mappM (tcStdSyntaxName DoOrigin io_ty) monadNames ;
429 return (ids, HsDo DoExpr tc_stmts io_ids io_ret_ty noSrcLoc)
432 -- Simplify the context right here, so that we fail
433 -- if there aren't enough instances. Notably, when we see
435 -- we use recoverTc_ to try it <- e
436 -- and then let it = e
437 -- It's the simplify step that rejects the first.
438 traceTc (text "tcs 3") ;
439 const_binds <- tcSimplifyInteractive lie ;
441 -- Build result expression and zonk it
442 let { expr = mkHsLet const_binds tc_expr } ;
443 zonked_expr <- zonkTopExpr expr ;
444 zonked_ids <- zonkTopBndrs ids ;
446 return (zonked_ids, zonked_expr)
449 combine stmt (ids, stmts) = (ids, stmt:stmts)
453 tcRnExpr just finds the type of an expression
456 tcRnExpr :: HscEnv -> PersistentCompilerState
457 -> InteractiveContext
459 -> IO (PersistentCompilerState, Maybe Type)
460 tcRnExpr hsc_env pcs ictxt rdr_expr
461 = initTc hsc_env pcs iNTERACTIVE $
462 setInteractiveContext ictxt $ do {
464 (rn_expr, fvs) <- initRnInteractive ictxt (rnExpr rdr_expr) ;
467 -- Suck in the supporting declarations and typecheck them
468 tcg_env <- importSupportingDecls (fvs `plusFV` ubiquitousNames) ;
469 setGblEnv tcg_env $ do {
471 -- Now typecheck the expression;
472 -- it might have a rank-2 type (e.g. :t runST)
473 ((tc_expr, res_ty), lie) <- getLIE (tcInferRho rn_expr) ;
474 ((qtvs, _, dict_ids), lie_top) <- getLIE (tcSimplifyInfer smpl_doc (tyVarsOfType res_ty) lie) ;
475 tcSimplifyInteractive lie_top ;
477 let { all_expr_ty = mkForAllTys qtvs $
478 mkFunTys (map idType dict_ids) $
480 zonkTcType all_expr_ty
483 smpl_doc = ptext SLIT("main expression")
488 tcRnThing :: HscEnv -> PersistentCompilerState
489 -> InteractiveContext
491 -> IO (PersistentCompilerState, Maybe [TyThing])
492 -- Look up a RdrName and return all the TyThings it might be
493 -- A capitalised RdrName is given to us in the DataName namespace,
494 -- but we want to treat it as *both* a data constructor
495 -- *and* as a type or class constructor;
496 -- hence the call to dataTcOccs, and we return up to two results
497 tcRnThing hsc_env pcs ictxt rdr_name
498 = initTc hsc_env pcs iNTERACTIVE $
499 setInteractiveContext ictxt $ do {
501 -- If the identifier is a constructor (begins with an
502 -- upper-case letter), then we need to consider both
503 -- constructor and type class identifiers.
504 let { rdr_names = dataTcOccs rdr_name } ;
506 -- results :: [(Messages, Maybe Name)]
507 results <- initRnInteractive ictxt
508 (mapM (tryTc . lookupOccRn) rdr_names) ;
510 -- The successful lookups will be (Just name)
511 let { (warns_s, good_names) = unzip [ (msgs, name)
512 | (msgs, Just name) <- results] ;
513 errs_s = [msgs | (msgs, Nothing) <- results] } ;
515 -- Fail if nothing good happened, else add warnings
516 if null good_names then
517 -- No lookup succeeded, so
518 -- pick the first error message and report it
519 -- ToDo: If one of the errors is "could be Foo.X or Baz.X",
520 -- while the other is "X is not in scope",
521 -- we definitely want the former; but we might pick the latter
522 do { addMessages (head errs_s) ; failM }
523 else -- Add deprecation warnings
524 mapM_ addMessages warns_s ;
526 -- Slurp in the supporting declarations
527 tcg_env <- importSupportingDecls (mkFVs good_names) ;
528 setGblEnv tcg_env $ do {
530 -- And lookup up the entities
531 mapM tcLookupGlobal good_names
537 setInteractiveContext :: InteractiveContext -> TcRn m a -> TcRn m a
538 setInteractiveContext icxt thing_inside
539 = traceTc (text "setIC" <+> ppr (ic_type_env icxt)) `thenM_`
540 updGblEnv (\ env -> env { tcg_rdr_env = ic_rn_gbl_env icxt,
541 tcg_type_env = ic_type_env icxt })
544 initRnInteractive :: InteractiveContext -> RnM a -> TcM a
545 -- Set the local RdrEnv from the interactive context
546 initRnInteractive ictxt rn_thing
547 = initRn CmdLineMode $
548 setLocalRdrEnv (ic_rn_local_env ictxt) $
553 %************************************************************************
555 Type-checking external-core modules
557 %************************************************************************
560 tcRnExtCore :: HscEnv -> PersistentCompilerState
562 -> IO (PersistentCompilerState, Maybe ModGuts)
563 -- Nothing => some error occurred
565 tcRnExtCore hsc_env pcs (HsModule (Just this_mod) _ _ decls _ loc)
566 -- For external core, the module name is syntactically reqd
567 -- Rename the (Core) module. It's a bit like an interface
568 -- file: all names are original names
569 = do { showPass (hsc_dflags hsc_env) "Renamer/typechecker" ;
571 initTc hsc_env pcs this_mod $ addSrcLoc loc $ do {
573 -- Rename the source, only in interface mode.
574 -- rnSrcDecls handles fixity decls etc too, which won't occur
575 -- but that doesn't matter
576 let { local_group = mkGroup decls } ;
577 (_, rn_src_decls, dus) <- initRn (InterfaceMode this_mod)
578 (rnSrcDecls local_group) ;
581 -- Get the supporting decls
582 rn_imp_decls <- slurpImpDecls (duUses dus) ;
583 let { rn_decls = rn_src_decls `addImpDecls` rn_imp_decls } ;
585 -- Dump trace of renaming part
586 rnDump (ppr rn_decls) ;
587 rnStats rn_imp_decls ;
589 -- Typecheck them all together so that
590 -- any mutually recursive types are done right
591 tcg_env <- typecheckIfaceDecls rn_decls ;
592 setGblEnv tcg_env $ do {
594 -- Now the core bindings
595 core_prs <- tcCoreBinds (hs_coreds rn_decls) ;
596 tcExtendGlobalValEnv (map fst core_prs) $ do {
600 bndrs = map fst core_prs ;
601 my_exports = map (Avail . idName) bndrs ;
602 -- ToDo: export the data types also?
604 final_type_env = extendTypeEnvWithIds (tcg_type_env tcg_env) bndrs ;
606 mod_guts = ModGuts { mg_module = this_mod,
607 mg_usages = [], -- ToDo: compute usage
608 mg_dir_imps = [], -- ??
609 mg_deps = noDependencies, -- ??
610 mg_exports = my_exports,
611 mg_types = final_type_env,
612 mg_insts = tcg_insts tcg_env,
613 mg_rules = hsCoreRules (tcg_rules tcg_env),
614 mg_binds = [Rec core_prs],
617 mg_rdr_env = emptyGlobalRdrEnv,
618 mg_fix_env = emptyFixityEnv,
619 mg_deprecs = NoDeprecs,
623 tcCoreDump mod_guts ;
630 %************************************************************************
632 Type-checking the top level of a module
634 %************************************************************************
637 tcRnSrcDecls :: [RdrNameHsDecl] -> TcM (TcGblEnv, DefUses)
638 -- Returns the variables free in the decls
639 -- Reason: solely to report unused imports and bindings
641 = do { -- Do all the declarations
642 ((tc_envs, dus), lie) <- getLIE (tc_rn_src_decls decls) ;
644 -- tcSimplifyTop deals with constant or ambiguous InstIds.
645 -- How could there be ambiguous ones? They can only arise if a
646 -- top-level decl falls under the monomorphism
647 -- restriction, and no subsequent decl instantiates its
648 -- type. (Usually, ambiguous type variables are resolved
649 -- during the generalisation step.)
650 traceTc (text "Tc8") ;
651 setEnvs tc_envs $ do {
652 -- Setting the global env exposes the instances to tcSimplifyTop
653 -- Setting the local env exposes the local Ids, so that
654 -- we get better error messages (monomorphism restriction)
655 inst_binds <- tcSimplifyTop lie ;
657 -- Backsubstitution. This must be done last.
658 -- Even tcSimplifyTop may do some unification.
659 traceTc (text "Tc9") ;
660 let { (tcg_env, _) = tc_envs ;
661 TcGblEnv { tcg_type_env = type_env, tcg_binds = binds,
662 tcg_rules = rules, tcg_fords = fords } = tcg_env } ;
664 (bind_ids, binds', fords', rules') <- zonkTopDecls (binds `andMonoBinds` inst_binds)
667 return (tcg_env { tcg_type_env = extendTypeEnvWithIds type_env bind_ids,
668 tcg_binds = binds', tcg_rules = rules', tcg_fords = fords' },
672 tc_rn_src_decls :: [RdrNameHsDecl] -> TcM ((TcGblEnv, TcLclEnv), DefUses)
675 = do { let { (first_group, group_tail) = findSplice ds } ;
676 -- If ds is [] we get ([], Nothing)
678 -- Type check the decls up to, but not including, the first splice
679 (tc_envs@(_,tcl_env), src_dus1) <- tcRnGroup first_group ;
681 -- Bale out if errors; for example, error recovery when checking
682 -- the RHS of 'main' can mean that 'main' is not in the envt for
683 -- the subsequent checkMain test
688 -- If there is no splice, we're nearly done
690 Nothing -> do { -- Last thing: check for `main'
691 (tcg_env, main_fvs) <- checkMain ;
692 return ((tcg_env, tcl_env),
693 src_dus1 `plusDU` usesOnly main_fvs)
696 -- If there's a splice, we must carry on
697 Just (SpliceDecl splice_expr splice_loc, rest_ds) -> do {
699 failWithTc (text "Can't do a top-level splice; need a bootstrapped compiler")
702 -- Rename the splice expression, and get its supporting decls
703 (rn_splice_expr, splice_fvs) <- initRn SourceMode $
704 addSrcLoc splice_loc $
706 tcg_env <- importSupportingDecls (splice_fvs `plusFV` templateHaskellNames) ;
707 setGblEnv tcg_env $ do {
709 -- Execute the splice
710 spliced_decls <- tcSpliceDecls rn_splice_expr ;
712 -- Glue them on the front of the remaining decls and loop
713 (tc_envs, src_dus2) <- tc_rn_src_decls (spliced_decls ++ rest_ds) ;
715 return (tc_envs, src_dus1 `plusDU` usesOnly splice_fvs `plusDU` src_dus2)
722 %************************************************************************
724 Type-checking the top level of a module
726 %************************************************************************
728 tcRnGroup takes a bunch of top-level source-code declarations, and
730 * gets supporting declarations from interface files
733 * and augments the TcGblEnv with the results
735 In Template Haskell it may be called repeatedly for each group of
736 declarations. It expects there to be an incoming TcGblEnv in the
737 monad; it augments it and returns the new TcGblEnv.
740 tcRnGroup :: HsGroup RdrName -> TcM ((TcGblEnv, TcLclEnv), DefUses)
741 -- Returns the variables free in the decls, for unused-binding reporting
743 = do { -- Rename the declarations
744 (tcg_env, rn_decls, src_dus) <- rnTopSrcDecls decls ;
745 setGblEnv tcg_env $ do {
747 -- Typecheck the declarations
748 tc_envs <- tcTopSrcDecls rn_decls ;
750 return (tc_envs, src_dus)
753 ------------------------------------------------
754 rnTopSrcDecls :: HsGroup RdrName -> TcM (TcGblEnv, HsGroup Name, DefUses)
756 = do { -- Bring top level binders into scope
757 (rdr_env, imports) <- importsFromLocalDecls group ;
758 updGblEnv (\gbl -> gbl { tcg_rdr_env = rdr_env `plusGlobalRdrEnv`
760 tcg_imports = imports `plusImportAvails`
764 failIfErrsM ; -- No point in continuing if (say) we have duplicate declarations
766 -- Rename the source decls
767 (tcg_env, rn_src_decls, src_dus) <- initRn SourceMode (rnSrcDecls group) ;
768 setGblEnv tcg_env $ do {
772 -- Import consquential imports
773 let { src_fvs = duUses src_dus } ;
774 rn_imp_decls <- slurpImpDecls (src_fvs `plusFV` implicitModuleFVs src_fvs) ;
775 let { rn_decls = rn_src_decls `addImpDecls` rn_imp_decls } ;
777 -- Dump trace of renaming part
778 rnDump (ppr rn_decls) ;
779 rnStats rn_imp_decls ;
781 return (tcg_env, rn_decls, src_dus)
784 ------------------------------------------------
785 tcTopSrcDecls :: HsGroup Name -> TcM (TcGblEnv, TcLclEnv)
787 (HsGroup { hs_tyclds = tycl_decls,
788 hs_instds = inst_decls,
789 hs_fords = foreign_decls,
790 hs_defds = default_decls,
791 hs_ruleds = rule_decls,
792 hs_valds = val_binds })
793 = do { -- Type-check the type and class decls, and all imported decls
794 -- The latter come in via tycl_decls
795 traceTc (text "Tc2") ;
796 tcg_env <- tcTyClDecls tycl_decls ;
797 setGblEnv tcg_env $ do {
799 -- Source-language instances, including derivings,
800 -- and import the supporting declarations
801 traceTc (text "Tc3") ;
802 (tcg_env, inst_infos, deriv_binds, fvs) <- tcInstDecls1 tycl_decls inst_decls ;
803 setGblEnv tcg_env $ do {
804 tcg_env <- importSupportingDecls fvs ;
805 setGblEnv tcg_env $ do {
807 -- Foreign import declarations next. No zonking necessary
808 -- here; we can tuck them straight into the global environment.
809 traceTc (text "Tc4") ;
810 (fi_ids, fi_decls) <- tcForeignImports foreign_decls ;
811 tcExtendGlobalValEnv fi_ids $
812 updGblEnv (\gbl -> gbl { tcg_fords = tcg_fords gbl ++ fi_decls })
815 -- Default declarations
816 traceTc (text "Tc4a") ;
817 default_tys <- tcDefaults default_decls ;
818 updGblEnv (\gbl -> gbl { tcg_default = default_tys }) $ do {
820 -- Value declarations next
821 -- We also typecheck any extra binds that came out
822 -- of the "deriving" process
823 traceTc (text "Tc5") ;
824 (tc_val_binds, lcl_env) <- tcTopBinds (val_binds `ThenBinds` deriv_binds) ;
825 setLclTypeEnv lcl_env $ do {
827 -- Second pass over class and instance declarations,
828 -- plus rules and foreign exports, to generate bindings
829 traceTc (text "Tc6") ;
830 (cls_dm_binds, dm_ids) <- tcClassDecls2 tycl_decls ;
831 tcExtendGlobalValEnv dm_ids $ do {
832 inst_binds <- tcInstDecls2 inst_infos ;
833 showLIE (text "after instDecls2") ;
836 -- They need to be zonked, so we return them
837 traceTc (text "Tc7") ;
838 (foe_binds, foe_decls) <- tcForeignExports foreign_decls ;
841 -- Need to partition them because the source rules
842 -- must be zonked before adding them to tcg_rules
843 -- NB: built-in rules come in as IfaceRuleOut's, and
844 -- get added to tcg_rules right here by tcExtendRules
845 rules <- tcRules rule_decls ;
846 let { (src_rules, iface_rules) = partition isSrcRule rules } ;
847 tcExtendRules iface_rules $ do {
850 tcg_env <- getGblEnv ;
851 let { all_binds = tc_val_binds `AndMonoBinds`
852 inst_binds `AndMonoBinds`
853 cls_dm_binds `AndMonoBinds`
856 -- Extend the GblEnv with the (as yet un-zonked)
857 -- bindings, rules, foreign decls
858 tcg_env' = tcg_env { tcg_binds = tcg_binds tcg_env `andMonoBinds` all_binds,
859 tcg_rules = tcg_rules tcg_env ++ src_rules,
860 tcg_fords = tcg_fords tcg_env ++ foe_decls } } ;
862 return (tcg_env', lcl_env)
867 tcTyClDecls :: [RenamedTyClDecl]
870 -- tcTyClDecls deals with
871 -- type and class decls (some source, some imported)
872 -- interface signatures (checked lazily)
874 -- It returns the TcGblEnv for this module, and side-effects the
875 -- persistent compiler state to reflect the things imported from
878 tcTyClDecls tycl_decls
880 -- tcTyAndClassDecls recovers internally, but if anything gave rise to
881 -- an error we'd better stop now, to avoid a cascade
883 traceTc (text "TyCl1") `thenM_`
884 tcTyAndClassDecls tycl_decls `thenM` \ tcg_env ->
885 -- Returns the extended environment
888 traceTc (text "TyCl2") `thenM_`
889 tcInterfaceSigs tycl_decls `thenM` \ tcg_env ->
890 -- Returns the extended environment
897 %************************************************************************
899 Load the old interface file for this module (unless
900 we have it aleady), and check whether it is up to date
903 %************************************************************************
906 checkOldIface :: HscEnv
907 -> PersistentCompilerState
909 -> FilePath -- Where the interface file is
910 -> Bool -- Source unchanged
911 -> Maybe ModIface -- Old interface from compilation manager, if any
912 -> IO (PersistentCompilerState, Maybe (RecompileRequired, Maybe ModIface))
913 -- Nothing <=> errors happened
915 checkOldIface hsc_env pcs mod iface_path source_unchanged maybe_iface
916 = do { showPass (hsc_dflags hsc_env)
917 ("Checking old interface for " ++ moduleUserString mod) ;
919 initTc hsc_env pcs mod
920 (check_old_iface iface_path source_unchanged maybe_iface)
923 check_old_iface iface_path source_unchanged maybe_iface
924 = -- CHECK WHETHER THE SOURCE HAS CHANGED
925 ifM (not source_unchanged)
926 (traceHiDiffs (nest 4 (text "Source file changed or recompilation check turned off")))
929 -- If the source has changed and we're in interactive mode, avoid reading
930 -- an interface; just return the one we might have been supplied with.
931 getGhciMode `thenM` \ ghci_mode ->
932 if (ghci_mode == Interactive) && not source_unchanged then
933 returnM (outOfDate, maybe_iface)
936 case maybe_iface of {
937 Just old_iface -> -- Use the one we already have
938 checkVersions source_unchanged old_iface `thenM` \ recomp ->
939 returnM (recomp, Just old_iface)
943 -- Try and read the old interface for the current module
944 -- from the .hi file left from the last time we compiled it
945 getModule `thenM` \ this_mod ->
946 readIface this_mod iface_path False `thenM` \ read_result ->
947 case read_result of {
948 Left err -> -- Old interface file not found, or garbled; give up
949 traceHiDiffs (text "FYI: cannot read old interface file:"
950 $$ nest 4 (text (showException err))) `thenM_`
951 returnM (outOfDate, Nothing)
953 ; Right parsed_iface ->
955 -- We found the file and parsed it; now load it
956 tryTc (initRn (InterfaceMode this_mod)
957 (loadOldIface parsed_iface)) `thenM` \ ((_,errs), mb_iface) ->
959 Nothing -> -- Something went wrong in loading. The main likely thing
960 -- is that the usages mentioned B.f, where B.hi and B.hs no
961 -- longer exist. Then newGlobalName2 fails with an error message
962 -- This isn't an error; we just don't have an old iface file to
963 -- look at. Spit out a traceHiDiffs for info though.
964 traceHiDiffs (text "FYI: loading old interface file failed"
965 $$ nest 4 (docToSDoc (pprBagOfErrors errs))) `thenM_`
966 return (outOfDate, Nothing)
970 -- At last, we have got the old iface; check its versions
971 checkVersions source_unchanged iface `thenM` \ recomp ->
972 returnM (recomp, Just iface)
977 %************************************************************************
979 Type-check and rename supporting declarations
980 This is used to deal with the free vars of a splice,
981 or derived code: slurp in the necessary declarations,
982 typecheck them, and add them to the EPS
984 %************************************************************************
987 importSupportingDecls :: FreeVars -> TcM TcGblEnv
988 -- Completely deal with the supporting imports needed
989 -- by the specified free-var set
990 importSupportingDecls fvs
991 = do { traceRn (text "Import supporting decls for" <+> ppr (nameSetToList fvs)) ;
992 decls <- slurpImpDecls fvs ;
993 traceRn (text "...namely:" <+> vcat (map ppr decls)) ;
994 typecheckIfaceDecls (mkGroup decls) }
996 typecheckIfaceDecls :: HsGroup Name -> TcM TcGblEnv
997 -- The decls are all interface-file declarations
998 -- Usually they are all from other modules, but when we are reading
999 -- this module's interface from a file, it's possible that some of
1000 -- them are for the module being compiled.
1001 -- That is why the tcExtendX functions need to do partitioning.
1003 -- If all the decls are from other modules, the returned TcGblEnv
1004 -- will have an empty tc_genv, but its tc_inst_env
1005 -- cache may have been augmented.
1006 typecheckIfaceDecls (HsGroup { hs_tyclds = tycl_decls,
1007 hs_instds = inst_decls,
1008 hs_ruleds = rule_decls })
1009 = do { -- Typecheck the type, class, and interface-sig decls
1010 tcg_env <- tcTyClDecls tycl_decls ;
1011 setGblEnv tcg_env $ do {
1013 -- Typecheck the instance decls, and rules
1014 -- Note that imported dictionary functions are already
1015 -- in scope from the preceding tcTyClDecls
1016 tcIfaceInstDecls inst_decls `thenM` \ dfuns ->
1017 tcExtendInstEnv dfuns $
1018 tcRules rule_decls `thenM` \ rules ->
1019 tcExtendRules rules $
1021 getGblEnv -- Return the environment
1027 %*********************************************************
1029 mkGlobalContext: make up an interactive context
1031 Used for initialising the lexical environment
1032 of the interactive read-eval-print loop
1034 %*********************************************************
1039 :: HscEnv -> PersistentCompilerState
1040 -> [Module] -- Expose these modules' top-level scope
1041 -> [Module] -- Expose these modules' exports only
1042 -> IO (PersistentCompilerState, Maybe GlobalRdrEnv)
1044 mkGlobalContext hsc_env pcs toplevs exports
1045 = initTc hsc_env pcs iNTERACTIVE $ do {
1047 toplev_envs <- mappM getTopLevScope toplevs ;
1048 export_envs <- mappM getModuleExports exports ;
1049 returnM (foldr plusGlobalRdrEnv emptyGlobalRdrEnv
1050 (toplev_envs ++ export_envs))
1053 getTopLevScope :: Module -> TcRn m GlobalRdrEnv
1055 = do { iface <- loadInterface contextDoc (moduleName mod) (ImportByUser False) ;
1056 case mi_globals iface of
1057 Nothing -> panic "getTopLevScope"
1058 Just env -> returnM env }
1060 getModuleExports :: Module -> TcRn m GlobalRdrEnv
1061 getModuleExports mod
1062 = do { iface <- loadInterface contextDoc (moduleName mod) (ImportByUser False) ;
1063 returnM (foldl add emptyGlobalRdrEnv (mi_exports iface)) }
1065 prov_fn n = NonLocalDef ImplicitImport
1066 add env (mod,avails)
1067 = plusGlobalRdrEnv env (mkGlobalRdrEnv mod True prov_fn avails NoDeprecs)
1069 contextDoc = text "context for compiling statements"
1075 -> PersistentCompilerState -- IN: persistent compiler state
1076 -> Module -- module to inspect
1077 -> Bool -- grab just the exports, or the whole toplev
1078 -> IO (PersistentCompilerState, Maybe [TyThing])
1080 getModuleContents hsc_env pcs mod exports_only
1081 = initTc hsc_env pcs iNTERACTIVE $ do {
1083 -- Load the interface if necessary (a home module will certainly
1084 -- alraedy be loaded, but a package module might not be)
1085 iface <- loadInterface contextDoc (moduleName mod) (ImportByUser False) ;
1087 let { export_names = availsToNameSet export_avails ;
1088 export_avails = [ avail | (mn, avails) <- mi_exports iface,
1089 avail <- avails ] } ;
1091 all_names <- if exports_only then
1093 else case mi_globals iface of {
1095 return (get_locals rdr_env) ;
1097 Nothing -> do { addErr (noRdrEnvErr mod) ;
1098 return export_names } } ;
1099 -- Invariant; we only have (not exports_only)
1100 -- for a home module so it must already be in the HIT
1101 -- So the Nothing case is a bug
1103 env <- importSupportingDecls all_names ;
1104 setGblEnv env (mappM tcLookupGlobal (nameSetToList all_names))
1107 -- Grab all the things from the global env that are locally def'd
1108 get_locals rdr_env = mkNameSet [ gre_name gre
1109 | elts <- rdrEnvElts rdr_env,
1112 -- Make a set because a name is often in the envt in
1113 -- both qualified and unqualified forms
1115 noRdrEnvErr mod = ptext SLIT("No top-level environment available for module")
1116 <+> quotes (ppr mod)
1120 %************************************************************************
1124 %************************************************************************
1128 = do { ghci_mode <- getGhciMode ;
1129 tcg_env <- getGblEnv ;
1131 mb_main_mod <- readMutVar v_MainModIs ;
1132 mb_main_fn <- readMutVar v_MainFunIs ;
1133 let { main_mod = case mb_main_mod of {
1134 Just mod -> mkModuleName mod ;
1135 Nothing -> mAIN_Name } ;
1136 main_fn = case mb_main_fn of {
1137 Just fn -> mkRdrUnqual (mkVarOcc (mkFastString fn)) ;
1138 Nothing -> main_RDR_Unqual } } ;
1140 check_main ghci_mode tcg_env main_mod main_fn
1144 check_main ghci_mode tcg_env main_mod main_fn
1145 -- If we are in module Main, check that 'main' is defined.
1146 -- It may be imported from another module, in which case
1147 -- we have to drag in its.
1149 -- Also form the definition
1150 -- $main = runIO main
1151 -- so we need to slurp in runIO too.
1153 -- ToDo: We have to return the main_name separately, because it's a
1154 -- bona fide 'use', and should be recorded as such, but the others
1157 -- Blimey: a whole page of code to do this...
1159 | mod_name /= main_mod
1160 = return (tcg_env, emptyFVs)
1162 -- Check that 'main' is in scope
1163 -- It might be imported from another module!
1165 -- We use a guard for this (rather than letting lookupSrcName fail)
1166 -- because it's not an error in ghci)
1167 | not (main_fn `elemRdrEnv` rdr_env)
1168 = do { complain_no_main; return (tcg_env, emptyFVs) }
1170 | otherwise -- OK, so the appropriate 'main' is in scope
1172 = do { main_name <- lookupSrcName main_fn ;
1174 tcg_env <- importSupportingDecls (unitFV runIOName) ;
1176 addSrcLoc (getSrcLoc main_name) $
1177 addErrCtxt mainCtxt $
1178 setGblEnv tcg_env $ do {
1180 -- :Main.main :: IO () = runIO main
1181 let { rhs = HsApp (HsVar runIOName) (HsVar main_name) } ;
1182 (main_expr, ty) <- tcInferRho rhs ;
1184 let { root_main_id = setIdLocalExported (mkLocalId rootMainName ty) ;
1185 main_bind = VarMonoBind root_main_id main_expr ;
1186 tcg_env' = tcg_env { tcg_binds = tcg_binds tcg_env
1187 `andMonoBinds` main_bind } } ;
1189 return (tcg_env', unitFV main_name)
1192 mod_name = moduleName (tcg_mod tcg_env)
1193 rdr_env = tcg_rdr_env tcg_env
1195 complain_no_main | ghci_mode == Interactive = return ()
1196 | otherwise = failWithTc noMainMsg
1197 -- In interactive mode, don't worry about the absence of 'main'
1198 -- In other modes, fail altogether, so that we don't go on
1199 -- and complain a second time when processing the export list.
1201 mainCtxt = ptext SLIT("When checking the type of the main function") <+> quotes (ppr main_fn)
1202 noMainMsg = ptext SLIT("The main function") <+> quotes (ppr main_fn)
1203 <+> ptext SLIT("is not defined in module") <+> quotes (ppr main_mod)
1207 %************************************************************************
1211 %************************************************************************
1214 rnDump :: SDoc -> TcRn m ()
1215 -- Dump, with a banner, if -ddump-rn
1216 rnDump doc = dumpOptTcRn Opt_D_dump_rn (mkDumpDoc "Renamer" doc)
1218 tcDump :: TcGblEnv -> TcRn m ()
1220 = do { dflags <- getDOpts ;
1222 -- Dump short output if -ddump-types or -ddump-tc
1223 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1224 (dumpTcRn short_dump) ;
1226 -- Dump bindings if -ddump-tc
1227 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump)
1230 short_dump = pprTcGblEnv env
1231 full_dump = ppr (tcg_binds env)
1232 -- NB: foreign x-d's have undefined's in their types;
1233 -- hence can't show the tc_fords
1236 = do { dflags <- getDOpts ;
1237 ifM (dopt Opt_D_dump_types dflags || dopt Opt_D_dump_tc dflags)
1238 (dumpTcRn (pprModGuts mod_guts)) ;
1240 -- Dump bindings if -ddump-tc
1241 dumpOptTcRn Opt_D_dump_tc (mkDumpDoc "Typechecker" full_dump) }
1243 full_dump = pprCoreBindings (mg_binds mod_guts)
1245 -- It's unpleasant having both pprModGuts and pprModDetails here
1246 pprTcGblEnv :: TcGblEnv -> SDoc
1247 pprTcGblEnv (TcGblEnv { tcg_type_env = type_env,
1248 tcg_insts = dfun_ids,
1250 tcg_imports = imports })
1251 = vcat [ ppr_types dfun_ids type_env
1252 , ppr_insts dfun_ids
1253 , vcat (map ppr rules)
1254 , ppr_gen_tycons (typeEnvTyCons type_env)
1255 , ptext SLIT("Dependent modules:") <+> ppr (moduleEnvElts (imp_dep_mods imports))
1256 , ptext SLIT("Dependent packages:") <+> ppr (imp_dep_pkgs imports)]
1258 pprModGuts :: ModGuts -> SDoc
1259 pprModGuts (ModGuts { mg_types = type_env,
1261 = vcat [ ppr_types [] type_env,
1265 ppr_types :: [Var] -> TypeEnv -> SDoc
1266 ppr_types dfun_ids type_env
1267 = text "TYPE SIGNATURES" $$ nest 4 (ppr_sigs ids)
1269 ids = [id | id <- typeEnvIds type_env, want_sig id]
1270 want_sig id | opt_PprStyle_Debug = True
1271 | otherwise = isLocalId id &&
1272 isExternalName (idName id) &&
1273 not (id `elem` dfun_ids)
1274 -- isLocalId ignores data constructors, records selectors etc.
1275 -- The isExternalName ignores local dictionary and method bindings
1276 -- that the type checker has invented. Top-level user-defined things
1277 -- have External names.
1279 ppr_insts :: [Var] -> SDoc
1280 ppr_insts [] = empty
1281 ppr_insts dfun_ids = text "INSTANCES" $$ nest 4 (ppr_sigs dfun_ids)
1283 ppr_sigs :: [Var] -> SDoc
1285 -- Print type signatures
1286 -- Convert to HsType so that we get source-language style printing
1287 -- And sort by RdrName
1288 = vcat $ map ppr_sig $ sortLt lt_sig $
1289 [ (getRdrName id, toHsType (tidyTopType (idType id)))
1292 lt_sig (n1,_) (n2,_) = n1 < n2
1293 ppr_sig (n,t) = ppr n <+> dcolon <+> ppr t
1296 ppr_rules :: [IdCoreRule] -> SDoc
1297 ppr_rules [] = empty
1298 ppr_rules rs = vcat [ptext SLIT("{-# RULES"),
1299 nest 4 (pprIdRules rs),
1302 ppr_gen_tycons [] = empty
1303 ppr_gen_tycons tcs = vcat [ptext SLIT("Generic type constructor details:"),
1304 nest 2 (vcat (map ppr_gen_tycon tcs))
1307 -- x&y are now Id's, not CoreExpr's
1309 | Just ep <- tyConGenInfo tycon
1310 = (ppr tycon <> colon) $$ nest 4 (ppr_ep ep)
1312 | otherwise = ppr tycon <> colon <+> ptext SLIT("Not derivable")
1315 = vcat [ ptext SLIT("Rep type:") <+> ppr (tcFunResultTy from_tau),
1316 ptext SLIT("From:") <+> ppr (unfoldingTemplate (idUnfolding from)),
1317 ptext SLIT("To:") <+> ppr (unfoldingTemplate (idUnfolding to))
1320 (_,from_tau) = tcSplitForAllTys (idType from)