2 % (c) The University of Glasgow 2006
3 % (c) The AQUA Project, Glasgow University, 1996-1998
6 TcHsSyn: Specialisations of the @HsSyn@ syntax for the typechecker
8 This module is an extension of @HsSyn@ syntax, for use in the type
13 mkHsConApp, mkHsDictLet, mkHsApp,
14 hsLitType, hsLPatType, hsPatType,
15 mkHsAppTy, mkSimpleHsAlt,
17 shortCutLit, hsOverLitName,
19 -- re-exported from TcMonad
22 zonkTopDecls, zonkTopExpr, zonkTopLExpr,
26 #include "HsVersions.h"
29 import HsSyn -- oodles of it
50 import DynFlags( DynFlag(..) )
58 thenM :: Monad a => a b -> (b -> a c) -> a c
61 returnM :: Monad m => a -> m a
64 mappM :: (Monad m) => (a -> m b) -> [a] -> m [b]
69 %************************************************************************
71 \subsection[mkFailurePair]{Code for pattern-matching and other failures}
73 %************************************************************************
75 Note: If @hsLPatType@ doesn't bear a strong resemblance to @exprType@,
76 then something is wrong.
78 hsLPatType :: OutPat Id -> Type
79 hsLPatType (L _ pat) = hsPatType pat
81 hsPatType :: Pat Id -> Type
82 hsPatType (ParPat pat) = hsLPatType pat
83 hsPatType (WildPat ty) = ty
84 hsPatType (VarPat var) = idType var
85 hsPatType (BangPat pat) = hsLPatType pat
86 hsPatType (LazyPat pat) = hsLPatType pat
87 hsPatType (LitPat lit) = hsLitType lit
88 hsPatType (AsPat var _) = idType (unLoc var)
89 hsPatType (ViewPat _ _ ty) = ty
90 hsPatType (ListPat _ ty) = mkListTy ty
91 hsPatType (PArrPat _ ty) = mkPArrTy ty
92 hsPatType (TuplePat _ _ ty) = ty
93 hsPatType (ConPatOut { pat_ty = ty }) = ty
94 hsPatType (SigPatOut _ ty) = ty
95 hsPatType (NPat lit _ _) = overLitType lit
96 hsPatType (NPlusKPat id _ _ _) = idType (unLoc id)
97 hsPatType (CoPat _ _ ty) = ty
98 hsPatType p = pprPanic "hsPatType" (ppr p)
100 hsLitType :: HsLit -> TcType
101 hsLitType (HsChar _) = charTy
102 hsLitType (HsCharPrim _) = charPrimTy
103 hsLitType (HsString _) = stringTy
104 hsLitType (HsStringPrim _) = addrPrimTy
105 hsLitType (HsInt _) = intTy
106 hsLitType (HsIntPrim _) = intPrimTy
107 hsLitType (HsWordPrim _) = wordPrimTy
108 hsLitType (HsInteger _ ty) = ty
109 hsLitType (HsRat _ ty) = ty
110 hsLitType (HsFloatPrim _) = floatPrimTy
111 hsLitType (HsDoublePrim _) = doublePrimTy
114 Overloaded literals. Here mainly becuase it uses isIntTy etc
117 shortCutLit :: OverLitVal -> TcType -> Maybe (HsExpr TcId)
118 shortCutLit (HsIntegral i) ty
119 | isIntTy ty && inIntRange i = Just (HsLit (HsInt i))
120 | isWordTy ty && inWordRange i = Just (mkLit wordDataCon (HsWordPrim i))
121 | isIntegerTy ty = Just (HsLit (HsInteger i ty))
122 | otherwise = shortCutLit (HsFractional (fromInteger i)) ty
123 -- The 'otherwise' case is important
124 -- Consider (3 :: Float). Syntactically it looks like an IntLit,
125 -- so we'll call shortCutIntLit, but of course it's a float
126 -- This can make a big difference for programs with a lot of
127 -- literals, compiled without -O
129 shortCutLit (HsFractional f) ty
130 | isFloatTy ty = Just (mkLit floatDataCon (HsFloatPrim f))
131 | isDoubleTy ty = Just (mkLit doubleDataCon (HsDoublePrim f))
132 | otherwise = Nothing
134 shortCutLit (HsIsString s) ty
135 | isStringTy ty = Just (HsLit (HsString s))
136 | otherwise = Nothing
138 mkLit :: DataCon -> HsLit -> HsExpr Id
139 mkLit con lit = HsApp (nlHsVar (dataConWrapId con)) (nlHsLit lit)
141 ------------------------------
142 hsOverLitName :: OverLitVal -> Name
143 -- Get the canonical 'fromX' name for a particular OverLitVal
144 hsOverLitName (HsIntegral {}) = fromIntegerName
145 hsOverLitName (HsFractional {}) = fromRationalName
146 hsOverLitName (HsIsString {}) = fromStringName
149 %************************************************************************
151 \subsection[BackSubst-HsBinds]{Running a substitution over @HsBinds@}
153 %************************************************************************
156 -- zonkId is used *during* typechecking just to zonk the Id's type
157 zonkId :: TcId -> TcM TcId
159 = zonkTcType (idType id) `thenM` \ ty' ->
160 returnM (Id.setIdType id ty')
163 The rest of the zonking is done *after* typechecking.
164 The main zonking pass runs over the bindings
166 a) to convert TcTyVars to TyVars etc, dereferencing any bindings etc
167 b) convert unbound TcTyVar to Void
168 c) convert each TcId to an Id by zonking its type
170 The type variables are converted by binding mutable tyvars to immutable ones
171 and then zonking as normal.
173 The Ids are converted by binding them in the normal Tc envt; that
174 way we maintain sharing; eg an Id is zonked at its binding site and they
175 all occurrences of that Id point to the common zonked copy
177 It's all pretty boring stuff, because HsSyn is such a large type, and
178 the environment manipulation is tiresome.
181 data ZonkEnv = ZonkEnv (TcType -> TcM Type) -- How to zonk a type
182 (VarEnv Var) -- What variables are in scope
183 -- Maps an Id or EvVar to its zonked version; both have the same Name
184 -- Note that all evidence (coercion variables as well as dictionaries)
185 -- are kept in the ZonkEnv
186 -- Only *type* abstraction is done by side effect
187 -- Is only consulted lazily; hence knot-tying
189 emptyZonkEnv :: ZonkEnv
190 emptyZonkEnv = ZonkEnv zonkTypeZapping emptyVarEnv
192 extendZonkEnv :: ZonkEnv -> [Var] -> ZonkEnv
193 extendZonkEnv (ZonkEnv zonk_ty env) ids
194 = ZonkEnv zonk_ty (extendVarEnvList env [(id,id) | id <- ids])
196 extendZonkEnv1 :: ZonkEnv -> Var -> ZonkEnv
197 extendZonkEnv1 (ZonkEnv zonk_ty env) id
198 = ZonkEnv zonk_ty (extendVarEnv env id id)
200 setZonkType :: ZonkEnv -> (TcType -> TcM Type) -> ZonkEnv
201 setZonkType (ZonkEnv _ env) zonk_ty = ZonkEnv zonk_ty env
203 zonkEnvIds :: ZonkEnv -> [Id]
204 zonkEnvIds (ZonkEnv _ env) = varEnvElts env
206 zonkIdOcc :: ZonkEnv -> TcId -> Id
207 -- Ids defined in this module should be in the envt;
208 -- ignore others. (Actually, data constructors are also
209 -- not LocalVars, even when locally defined, but that is fine.)
210 -- (Also foreign-imported things aren't currently in the ZonkEnv;
211 -- that's ok because they don't need zonking.)
213 -- Actually, Template Haskell works in 'chunks' of declarations, and
214 -- an earlier chunk won't be in the 'env' that the zonking phase
215 -- carries around. Instead it'll be in the tcg_gbl_env, already fully
216 -- zonked. There's no point in looking it up there (except for error
217 -- checking), and it's not conveniently to hand; hence the simple
218 -- 'orElse' case in the LocalVar branch.
220 -- Even without template splices, in module Main, the checking of
221 -- 'main' is done as a separate chunk.
222 zonkIdOcc (ZonkEnv _zonk_ty env) id
223 | isLocalVar id = lookupVarEnv env id `orElse` id
226 zonkIdOccs :: ZonkEnv -> [TcId] -> [Id]
227 zonkIdOccs env ids = map (zonkIdOcc env) ids
229 -- zonkIdBndr is used *after* typechecking to get the Id's type
230 -- to its final form. The TyVarEnv give
231 zonkIdBndr :: ZonkEnv -> TcId -> TcM Id
233 = zonkTcTypeToType env (idType id) `thenM` \ ty' ->
234 returnM (Id.setIdType id ty')
236 zonkIdBndrs :: ZonkEnv -> [TcId] -> TcM [Id]
237 zonkIdBndrs env ids = mappM (zonkIdBndr env) ids
239 zonkTopBndrs :: [TcId] -> TcM [Id]
240 zonkTopBndrs ids = zonkIdBndrs emptyZonkEnv ids
242 zonkEvBndrsX :: ZonkEnv -> [EvVar] -> TcM (ZonkEnv, [Var])
243 zonkEvBndrsX = mapAccumLM zonkEvBndrX
245 zonkEvBndrX :: ZonkEnv -> EvVar -> TcM (ZonkEnv, EvVar)
246 -- Works for dictionaries and coercions
248 = do { var' <- zonkEvBndr env var
249 ; return (extendZonkEnv1 env var', var') }
251 zonkEvBndr :: ZonkEnv -> EvVar -> TcM EvVar
252 -- Works for dictionaries and coercions
253 -- Does not extend the ZonkEnv
255 = do { ty' <- zonkTcTypeToType env (varType var)
256 ; return (setVarType var ty') }
258 zonkEvVarOcc :: ZonkEnv -> EvVar -> EvVar
259 zonkEvVarOcc env v = zonkIdOcc env v
264 zonkTopExpr :: HsExpr TcId -> TcM (HsExpr Id)
265 zonkTopExpr e = zonkExpr emptyZonkEnv e
267 zonkTopLExpr :: LHsExpr TcId -> TcM (LHsExpr Id)
268 zonkTopLExpr e = zonkLExpr emptyZonkEnv e
270 zonkTopDecls :: Bag EvBind
271 -> LHsBinds TcId -> NameSet
272 -> [LRuleDecl TcId] -> [LTcSpecPrag] -> [LForeignDecl TcId]
279 zonkTopDecls ev_binds binds sig_ns rules imp_specs fords
280 = do { (env1, ev_binds') <- zonkEvBinds emptyZonkEnv ev_binds
282 -- Warn about missing signatures
283 -- Do this only when we we have a type to offer
284 ; warn_missing_sigs <- doptM Opt_WarnMissingSigs
285 ; let sig_warn | warn_missing_sigs = topSigWarn sig_ns
286 | otherwise = noSigWarn
288 ; (env2, binds') <- zonkRecMonoBinds env1 sig_warn binds
289 -- Top level is implicitly recursive
290 ; rules' <- zonkRules env2 rules
291 ; specs' <- zonkLTcSpecPrags env2 imp_specs
292 ; fords' <- zonkForeignExports env2 fords
293 ; return (zonkEnvIds env2, ev_binds', binds', fords', specs', rules') }
295 ---------------------------------------------
296 zonkLocalBinds :: ZonkEnv -> HsLocalBinds TcId -> TcM (ZonkEnv, HsLocalBinds Id)
297 zonkLocalBinds env EmptyLocalBinds
298 = return (env, EmptyLocalBinds)
300 zonkLocalBinds _ (HsValBinds (ValBindsIn {}))
301 = panic "zonkLocalBinds" -- Not in typechecker output
303 zonkLocalBinds env (HsValBinds vb@(ValBindsOut binds sigs))
304 = do { warn_missing_sigs <- doptM Opt_WarnMissingLocalSigs
305 ; let sig_warn | not warn_missing_sigs = noSigWarn
306 | otherwise = localSigWarn sig_ns
307 sig_ns = getTypeSigNames vb
308 ; (env1, new_binds) <- go env sig_warn binds
309 ; return (env1, HsValBinds (ValBindsOut new_binds sigs)) }
313 go env sig_warn ((r,b):bs)
314 = do { (env1, b') <- zonkRecMonoBinds env sig_warn b
315 ; (env2, bs') <- go env1 sig_warn bs
316 ; return (env2, (r,b'):bs') }
318 zonkLocalBinds env (HsIPBinds (IPBinds binds dict_binds))
319 = mappM (wrapLocM zonk_ip_bind) binds `thenM` \ new_binds ->
321 env1 = extendZonkEnv env [ipNameName n | L _ (IPBind n _) <- new_binds]
323 zonkTcEvBinds env1 dict_binds `thenM` \ (env2, new_dict_binds) ->
324 returnM (env2, HsIPBinds (IPBinds new_binds new_dict_binds))
326 zonk_ip_bind (IPBind n e)
327 = mapIPNameTc (zonkIdBndr env) n `thenM` \ n' ->
328 zonkLExpr env e `thenM` \ e' ->
329 returnM (IPBind n' e')
331 ---------------------------------------------
332 zonkRecMonoBinds :: ZonkEnv -> SigWarn -> LHsBinds TcId -> TcM (ZonkEnv, LHsBinds Id)
333 zonkRecMonoBinds env sig_warn binds
334 = fixM (\ ~(_, new_binds) -> do
335 { let env1 = extendZonkEnv env (collectHsBindsBinders new_binds)
336 ; binds' <- zonkMonoBinds env1 sig_warn binds
337 ; return (env1, binds') })
339 ---------------------------------------------
340 type SigWarn = Bool -> [Id] -> TcM ()
341 -- Missing-signature warning
342 -- The Bool is True for an AbsBinds, False otherwise
345 noSigWarn _ _ = return ()
347 topSigWarn :: NameSet -> SigWarn
348 topSigWarn sig_ns _ ids = mapM_ (topSigWarnId sig_ns) ids
350 topSigWarnId :: NameSet -> Id -> TcM ()
351 -- The NameSet is the Ids that *lack* a signature
352 -- We have to do it this way round because there are
353 -- lots of top-level bindings that are generated by GHC
354 -- and that don't have signatures
355 topSigWarnId sig_ns id
356 | idName id `elemNameSet` sig_ns = warnMissingSig msg id
357 | otherwise = return ()
359 msg = ptext (sLit "Top-level binding with no type signature:")
361 localSigWarn :: NameSet -> SigWarn
362 localSigWarn sig_ns is_abs_bind ids
363 | not is_abs_bind = return ()
364 | otherwise = mapM_ (localSigWarnId sig_ns) ids
366 localSigWarnId :: NameSet -> Id -> TcM ()
367 -- NameSet are the Ids that *have* type signatures
368 localSigWarnId sig_ns id
369 | not (isSigmaTy (idType id)) = return ()
370 | idName id `elemNameSet` sig_ns = return ()
371 | otherwise = warnMissingSig msg id
373 msg = ptext (sLit "Polymophic local binding with no type signature:")
375 warnMissingSig :: SDoc -> Id -> TcM ()
376 warnMissingSig msg id
377 = do { env0 <- tcInitTidyEnv
378 ; let (env1, tidy_ty) = tidyOpenType env0 (idType id)
379 ; addWarnTcM (env1, mk_msg tidy_ty) }
381 mk_msg ty = sep [ msg, nest 2 $ pprHsVar (idName id) <+> dcolon <+> ppr ty ]
383 ---------------------------------------------
384 zonkMonoBinds :: ZonkEnv -> SigWarn -> LHsBinds TcId -> TcM (LHsBinds Id)
385 zonkMonoBinds env sig_warn binds = mapBagM (wrapLocM (zonk_bind env sig_warn)) binds
387 zonk_bind :: ZonkEnv -> SigWarn -> HsBind TcId -> TcM (HsBind Id)
388 zonk_bind env sig_warn bind@(PatBind { pat_lhs = pat, pat_rhs = grhss, pat_rhs_ty = ty})
389 = do { (_env, new_pat) <- zonkPat env pat -- Env already extended
390 ; sig_warn False (collectPatBinders new_pat)
391 ; new_grhss <- zonkGRHSs env grhss
392 ; new_ty <- zonkTcTypeToType env ty
393 ; return (bind { pat_lhs = new_pat, pat_rhs = new_grhss, pat_rhs_ty = new_ty }) }
395 zonk_bind env sig_warn (VarBind { var_id = var, var_rhs = expr, var_inline = inl })
396 = do { new_var <- zonkIdBndr env var
397 ; sig_warn False [new_var]
398 ; new_expr <- zonkLExpr env expr
399 ; return (VarBind { var_id = new_var, var_rhs = new_expr, var_inline = inl }) }
401 zonk_bind env sig_warn bind@(FunBind { fun_id = L loc var, fun_matches = ms
402 , fun_co_fn = co_fn })
403 = do { new_var <- zonkIdBndr env var
404 ; sig_warn False [new_var]
405 ; (env1, new_co_fn) <- zonkCoFn env co_fn
406 ; new_ms <- zonkMatchGroup env1 ms
407 ; return (bind { fun_id = L loc new_var, fun_matches = new_ms
408 , fun_co_fn = new_co_fn }) }
410 zonk_bind env sig_warn (AbsBinds { abs_tvs = tyvars, abs_ev_vars = evs
411 , abs_ev_binds = ev_binds
412 , abs_exports = exports
413 , abs_binds = val_binds })
414 = ASSERT( all isImmutableTyVar tyvars )
415 do { (env1, new_evs) <- zonkEvBndrsX env evs
416 ; (env2, new_ev_binds) <- zonkTcEvBinds env1 ev_binds
417 ; (new_val_bind, new_exports) <- fixM $ \ ~(new_val_binds, _) ->
418 do { let env3 = extendZonkEnv env2 (collectHsBindsBinders new_val_binds)
419 ; new_val_binds <- zonkMonoBinds env3 noSigWarn val_binds
420 ; new_exports <- mapM (zonkExport env3) exports
421 ; return (new_val_binds, new_exports) }
422 ; sig_warn True [b | (_,b,_,_) <- new_exports]
423 ; return (AbsBinds { abs_tvs = tyvars, abs_ev_vars = new_evs, abs_ev_binds = new_ev_binds
424 , abs_exports = new_exports, abs_binds = new_val_bind }) }
426 zonkExport env (tyvars, global, local, prags)
427 -- The tyvars are already zonked
428 = zonkIdBndr env global `thenM` \ new_global ->
429 zonkSpecPrags env prags `thenM` \ new_prags ->
430 returnM (tyvars, new_global, zonkIdOcc env local, new_prags)
432 zonkSpecPrags :: ZonkEnv -> TcSpecPrags -> TcM TcSpecPrags
433 zonkSpecPrags _ IsDefaultMethod = return IsDefaultMethod
434 zonkSpecPrags env (SpecPrags ps) = do { ps' <- zonkLTcSpecPrags env ps
435 ; return (SpecPrags ps') }
437 zonkLTcSpecPrags :: ZonkEnv -> [LTcSpecPrag] -> TcM [LTcSpecPrag]
438 zonkLTcSpecPrags env ps
441 zonk_prag (L loc (SpecPrag id co_fn inl))
442 = do { (_, co_fn') <- zonkCoFn env co_fn
443 ; return (L loc (SpecPrag (zonkIdOcc env id) co_fn' inl)) }
446 %************************************************************************
448 \subsection[BackSubst-Match-GRHSs]{Match and GRHSs}
450 %************************************************************************
453 zonkMatchGroup :: ZonkEnv -> MatchGroup TcId-> TcM (MatchGroup Id)
454 zonkMatchGroup env (MatchGroup ms ty)
455 = do { ms' <- mapM (zonkMatch env) ms
456 ; ty' <- zonkTcTypeToType env ty
457 ; return (MatchGroup ms' ty') }
459 zonkMatch :: ZonkEnv -> LMatch TcId-> TcM (LMatch Id)
460 zonkMatch env (L loc (Match pats _ grhss))
461 = do { (env1, new_pats) <- zonkPats env pats
462 ; new_grhss <- zonkGRHSs env1 grhss
463 ; return (L loc (Match new_pats Nothing new_grhss)) }
465 -------------------------------------------------------------------------
466 zonkGRHSs :: ZonkEnv -> GRHSs TcId -> TcM (GRHSs Id)
468 zonkGRHSs env (GRHSs grhss binds)
469 = zonkLocalBinds env binds `thenM` \ (new_env, new_binds) ->
471 zonk_grhs (GRHS guarded rhs)
472 = zonkStmts new_env guarded `thenM` \ (env2, new_guarded) ->
473 zonkLExpr env2 rhs `thenM` \ new_rhs ->
474 returnM (GRHS new_guarded new_rhs)
476 mappM (wrapLocM zonk_grhs) grhss `thenM` \ new_grhss ->
477 returnM (GRHSs new_grhss new_binds)
480 %************************************************************************
482 \subsection[BackSubst-HsExpr]{Running a zonkitution over a TypeCheckedExpr}
484 %************************************************************************
487 zonkLExprs :: ZonkEnv -> [LHsExpr TcId] -> TcM [LHsExpr Id]
488 zonkLExpr :: ZonkEnv -> LHsExpr TcId -> TcM (LHsExpr Id)
489 zonkExpr :: ZonkEnv -> HsExpr TcId -> TcM (HsExpr Id)
491 zonkLExprs env exprs = mappM (zonkLExpr env) exprs
492 zonkLExpr env expr = wrapLocM (zonkExpr env) expr
494 zonkExpr env (HsVar id)
495 = returnM (HsVar (zonkIdOcc env id))
497 zonkExpr env (HsIPVar id)
498 = returnM (HsIPVar (mapIPName (zonkIdOcc env) id))
500 zonkExpr env (HsLit (HsRat f ty))
501 = zonkTcTypeToType env ty `thenM` \ new_ty ->
502 returnM (HsLit (HsRat f new_ty))
504 zonkExpr _ (HsLit lit)
505 = returnM (HsLit lit)
507 zonkExpr env (HsOverLit lit)
508 = do { lit' <- zonkOverLit env lit
509 ; return (HsOverLit lit') }
511 zonkExpr env (HsLam matches)
512 = zonkMatchGroup env matches `thenM` \ new_matches ->
513 returnM (HsLam new_matches)
515 zonkExpr env (HsApp e1 e2)
516 = zonkLExpr env e1 `thenM` \ new_e1 ->
517 zonkLExpr env e2 `thenM` \ new_e2 ->
518 returnM (HsApp new_e1 new_e2)
520 zonkExpr env (HsBracketOut body bs)
521 = mappM zonk_b bs `thenM` \ bs' ->
522 returnM (HsBracketOut body bs')
524 zonk_b (n,e) = zonkLExpr env e `thenM` \ e' ->
527 zonkExpr _ (HsSpliceE s) = WARN( True, ppr s ) -- Should not happen
528 returnM (HsSpliceE s)
530 zonkExpr env (OpApp e1 op fixity e2)
531 = zonkLExpr env e1 `thenM` \ new_e1 ->
532 zonkLExpr env op `thenM` \ new_op ->
533 zonkLExpr env e2 `thenM` \ new_e2 ->
534 returnM (OpApp new_e1 new_op fixity new_e2)
536 zonkExpr env (NegApp expr op)
537 = zonkLExpr env expr `thenM` \ new_expr ->
538 zonkExpr env op `thenM` \ new_op ->
539 returnM (NegApp new_expr new_op)
541 zonkExpr env (HsPar e)
542 = zonkLExpr env e `thenM` \new_e ->
543 returnM (HsPar new_e)
545 zonkExpr env (SectionL expr op)
546 = zonkLExpr env expr `thenM` \ new_expr ->
547 zonkLExpr env op `thenM` \ new_op ->
548 returnM (SectionL new_expr new_op)
550 zonkExpr env (SectionR op expr)
551 = zonkLExpr env op `thenM` \ new_op ->
552 zonkLExpr env expr `thenM` \ new_expr ->
553 returnM (SectionR new_op new_expr)
555 zonkExpr env (ExplicitTuple tup_args boxed)
556 = do { new_tup_args <- mapM zonk_tup_arg tup_args
557 ; return (ExplicitTuple new_tup_args boxed) }
559 zonk_tup_arg (Present e) = do { e' <- zonkLExpr env e; return (Present e') }
560 zonk_tup_arg (Missing t) = do { t' <- zonkTcTypeToType env t; return (Missing t') }
562 zonkExpr env (HsCase expr ms)
563 = zonkLExpr env expr `thenM` \ new_expr ->
564 zonkMatchGroup env ms `thenM` \ new_ms ->
565 returnM (HsCase new_expr new_ms)
567 zonkExpr env (HsIf e0 e1 e2 e3)
568 = do { new_e0 <- fmapMaybeM (zonkExpr env) e0
569 ; new_e1 <- zonkLExpr env e1
570 ; new_e2 <- zonkLExpr env e2
571 ; new_e3 <- zonkLExpr env e3
572 ; returnM (HsIf new_e0 new_e1 new_e2 new_e3) }
574 zonkExpr env (HsLet binds expr)
575 = zonkLocalBinds env binds `thenM` \ (new_env, new_binds) ->
576 zonkLExpr new_env expr `thenM` \ new_expr ->
577 returnM (HsLet new_binds new_expr)
579 zonkExpr env (HsDo do_or_lc stmts body ty)
580 = zonkStmts env stmts `thenM` \ (new_env, new_stmts) ->
581 zonkLExpr new_env body `thenM` \ new_body ->
582 zonkTcTypeToType env ty `thenM` \ new_ty ->
583 zonkDo env do_or_lc `thenM` \ new_do_or_lc ->
584 returnM (HsDo new_do_or_lc new_stmts new_body new_ty)
586 zonkExpr env (ExplicitList ty exprs)
587 = zonkTcTypeToType env ty `thenM` \ new_ty ->
588 zonkLExprs env exprs `thenM` \ new_exprs ->
589 returnM (ExplicitList new_ty new_exprs)
591 zonkExpr env (ExplicitPArr ty exprs)
592 = zonkTcTypeToType env ty `thenM` \ new_ty ->
593 zonkLExprs env exprs `thenM` \ new_exprs ->
594 returnM (ExplicitPArr new_ty new_exprs)
596 zonkExpr env (RecordCon data_con con_expr rbinds)
597 = do { new_con_expr <- zonkExpr env con_expr
598 ; new_rbinds <- zonkRecFields env rbinds
599 ; return (RecordCon data_con new_con_expr new_rbinds) }
601 zonkExpr env (RecordUpd expr rbinds cons in_tys out_tys)
602 = do { new_expr <- zonkLExpr env expr
603 ; new_in_tys <- mapM (zonkTcTypeToType env) in_tys
604 ; new_out_tys <- mapM (zonkTcTypeToType env) out_tys
605 ; new_rbinds <- zonkRecFields env rbinds
606 ; return (RecordUpd new_expr new_rbinds cons new_in_tys new_out_tys) }
608 zonkExpr env (ExprWithTySigOut e ty)
609 = do { e' <- zonkLExpr env e
610 ; return (ExprWithTySigOut e' ty) }
612 zonkExpr _ (ExprWithTySig _ _) = panic "zonkExpr env:ExprWithTySig"
614 zonkExpr env (ArithSeq expr info)
615 = zonkExpr env expr `thenM` \ new_expr ->
616 zonkArithSeq env info `thenM` \ new_info ->
617 returnM (ArithSeq new_expr new_info)
619 zonkExpr env (PArrSeq expr info)
620 = zonkExpr env expr `thenM` \ new_expr ->
621 zonkArithSeq env info `thenM` \ new_info ->
622 returnM (PArrSeq new_expr new_info)
624 zonkExpr env (HsSCC lbl expr)
625 = zonkLExpr env expr `thenM` \ new_expr ->
626 returnM (HsSCC lbl new_expr)
628 zonkExpr env (HsTickPragma info expr)
629 = zonkLExpr env expr `thenM` \ new_expr ->
630 returnM (HsTickPragma info new_expr)
632 -- hdaume: core annotations
633 zonkExpr env (HsCoreAnn lbl expr)
634 = zonkLExpr env expr `thenM` \ new_expr ->
635 returnM (HsCoreAnn lbl new_expr)
637 -- arrow notation extensions
638 zonkExpr env (HsProc pat body)
639 = do { (env1, new_pat) <- zonkPat env pat
640 ; new_body <- zonkCmdTop env1 body
641 ; return (HsProc new_pat new_body) }
643 zonkExpr env (HsArrApp e1 e2 ty ho rl)
644 = zonkLExpr env e1 `thenM` \ new_e1 ->
645 zonkLExpr env e2 `thenM` \ new_e2 ->
646 zonkTcTypeToType env ty `thenM` \ new_ty ->
647 returnM (HsArrApp new_e1 new_e2 new_ty ho rl)
649 zonkExpr env (HsArrForm op fixity args)
650 = zonkLExpr env op `thenM` \ new_op ->
651 mappM (zonkCmdTop env) args `thenM` \ new_args ->
652 returnM (HsArrForm new_op fixity new_args)
654 zonkExpr env (HsWrap co_fn expr)
655 = zonkCoFn env co_fn `thenM` \ (env1, new_co_fn) ->
656 zonkExpr env1 expr `thenM` \ new_expr ->
657 return (HsWrap new_co_fn new_expr)
659 zonkExpr _ expr = pprPanic "zonkExpr" (ppr expr)
661 zonkCmdTop :: ZonkEnv -> LHsCmdTop TcId -> TcM (LHsCmdTop Id)
662 zonkCmdTop env cmd = wrapLocM (zonk_cmd_top env) cmd
664 zonk_cmd_top :: ZonkEnv -> HsCmdTop TcId -> TcM (HsCmdTop Id)
665 zonk_cmd_top env (HsCmdTop cmd stack_tys ty ids)
666 = zonkLExpr env cmd `thenM` \ new_cmd ->
667 zonkTcTypeToTypes env stack_tys `thenM` \ new_stack_tys ->
668 zonkTcTypeToType env ty `thenM` \ new_ty ->
669 mapSndM (zonkExpr env) ids `thenM` \ new_ids ->
670 returnM (HsCmdTop new_cmd new_stack_tys new_ty new_ids)
672 -------------------------------------------------------------------------
673 zonkCoFn :: ZonkEnv -> HsWrapper -> TcM (ZonkEnv, HsWrapper)
674 zonkCoFn env WpHole = return (env, WpHole)
675 zonkCoFn env (WpCompose c1 c2) = do { (env1, c1') <- zonkCoFn env c1
676 ; (env2, c2') <- zonkCoFn env1 c2
677 ; return (env2, WpCompose c1' c2') }
678 zonkCoFn env (WpCast co) = do { co' <- zonkTcTypeToType env co
679 ; return (env, WpCast co') }
680 zonkCoFn env (WpEvLam ev) = do { (env', ev') <- zonkEvBndrX env ev
681 ; return (env', WpEvLam ev') }
682 zonkCoFn env (WpEvApp arg) = do { arg' <- zonkEvTerm env arg
683 ; return (env, WpEvApp arg') }
684 zonkCoFn env (WpTyLam tv) = ASSERT( isImmutableTyVar tv )
685 return (env, WpTyLam tv)
686 zonkCoFn env (WpTyApp ty) = do { ty' <- zonkTcTypeToType env ty
687 ; return (env, WpTyApp ty') }
688 zonkCoFn env (WpLet bs) = do { (env1, bs') <- zonkTcEvBinds env bs
689 ; return (env1, WpLet bs') }
691 -------------------------------------------------------------------------
692 zonkDo :: ZonkEnv -> HsStmtContext Name -> TcM (HsStmtContext Name)
693 -- Only used for 'do', so the only Ids are in a MDoExpr table
694 zonkDo env (MDoExpr tbl) = do { tbl' <- mapSndM (zonkExpr env) tbl
695 ; return (MDoExpr tbl') }
696 zonkDo _ do_or_lc = return do_or_lc
698 -------------------------------------------------------------------------
699 zonkOverLit :: ZonkEnv -> HsOverLit TcId -> TcM (HsOverLit Id)
700 zonkOverLit env lit@(OverLit { ol_witness = e, ol_type = ty })
701 = do { ty' <- zonkTcTypeToType env ty
702 ; e' <- zonkExpr env e
703 ; return (lit { ol_witness = e', ol_type = ty' }) }
705 -------------------------------------------------------------------------
706 zonkArithSeq :: ZonkEnv -> ArithSeqInfo TcId -> TcM (ArithSeqInfo Id)
708 zonkArithSeq env (From e)
709 = zonkLExpr env e `thenM` \ new_e ->
712 zonkArithSeq env (FromThen e1 e2)
713 = zonkLExpr env e1 `thenM` \ new_e1 ->
714 zonkLExpr env e2 `thenM` \ new_e2 ->
715 returnM (FromThen new_e1 new_e2)
717 zonkArithSeq env (FromTo e1 e2)
718 = zonkLExpr env e1 `thenM` \ new_e1 ->
719 zonkLExpr env e2 `thenM` \ new_e2 ->
720 returnM (FromTo new_e1 new_e2)
722 zonkArithSeq env (FromThenTo e1 e2 e3)
723 = zonkLExpr env e1 `thenM` \ new_e1 ->
724 zonkLExpr env e2 `thenM` \ new_e2 ->
725 zonkLExpr env e3 `thenM` \ new_e3 ->
726 returnM (FromThenTo new_e1 new_e2 new_e3)
729 -------------------------------------------------------------------------
730 zonkStmts :: ZonkEnv -> [LStmt TcId] -> TcM (ZonkEnv, [LStmt Id])
731 zonkStmts env [] = return (env, [])
732 zonkStmts env (s:ss) = do { (env1, s') <- wrapLocSndM (zonkStmt env) s
733 ; (env2, ss') <- zonkStmts env1 ss
734 ; return (env2, s' : ss') }
736 zonkStmt :: ZonkEnv -> Stmt TcId -> TcM (ZonkEnv, Stmt Id)
737 zonkStmt env (ParStmt stmts_w_bndrs)
738 = mappM zonk_branch stmts_w_bndrs `thenM` \ new_stmts_w_bndrs ->
740 new_binders = concat (map snd new_stmts_w_bndrs)
741 env1 = extendZonkEnv env new_binders
743 return (env1, ParStmt new_stmts_w_bndrs)
745 zonk_branch (stmts, bndrs) = zonkStmts env stmts `thenM` \ (env1, new_stmts) ->
746 returnM (new_stmts, zonkIdOccs env1 bndrs)
748 zonkStmt env (RecStmt { recS_stmts = segStmts, recS_later_ids = lvs, recS_rec_ids = rvs
749 , recS_ret_fn = ret_id, recS_mfix_fn = mfix_id, recS_bind_fn = bind_id
750 , recS_rec_rets = rets, recS_dicts = binds })
751 = do { new_rvs <- zonkIdBndrs env rvs
752 ; new_lvs <- zonkIdBndrs env lvs
753 ; new_ret_id <- zonkExpr env ret_id
754 ; new_mfix_id <- zonkExpr env mfix_id
755 ; new_bind_id <- zonkExpr env bind_id
756 ; let env1 = extendZonkEnv env new_rvs
757 ; (env2, new_segStmts) <- zonkStmts env1 segStmts
758 -- Zonk the ret-expressions in an envt that
759 -- has the polymorphic bindings in the envt
760 ; new_rets <- mapM (zonkExpr env2) rets
761 ; let env3 = extendZonkEnv env new_lvs -- Only the lvs are needed
762 ; (env4, new_binds) <- zonkTcEvBinds env3 binds
764 RecStmt { recS_stmts = new_segStmts, recS_later_ids = new_lvs
765 , recS_rec_ids = new_rvs, recS_ret_fn = new_ret_id
766 , recS_mfix_fn = new_mfix_id, recS_bind_fn = new_bind_id
767 , recS_rec_rets = new_rets, recS_dicts = new_binds }) }
769 zonkStmt env (ExprStmt expr then_op ty)
770 = zonkLExpr env expr `thenM` \ new_expr ->
771 zonkExpr env then_op `thenM` \ new_then ->
772 zonkTcTypeToType env ty `thenM` \ new_ty ->
773 returnM (env, ExprStmt new_expr new_then new_ty)
775 zonkStmt env (TransformStmt stmts binders usingExpr maybeByExpr)
776 = do { (env', stmts') <- zonkStmts env stmts
777 ; let binders' = zonkIdOccs env' binders
778 ; usingExpr' <- zonkLExpr env' usingExpr
779 ; maybeByExpr' <- zonkMaybeLExpr env' maybeByExpr
780 ; return (env', TransformStmt stmts' binders' usingExpr' maybeByExpr') }
782 zonkStmt env (GroupStmt stmts binderMap by using)
783 = do { (env', stmts') <- zonkStmts env stmts
784 ; binderMap' <- mappM (zonkBinderMapEntry env') binderMap
785 ; by' <- fmapMaybeM (zonkLExpr env') by
786 ; using' <- fmapEitherM (zonkLExpr env) (zonkExpr env) using
787 ; let env'' = extendZonkEnv env' (map snd binderMap')
788 ; return (env'', GroupStmt stmts' binderMap' by' using') }
790 zonkBinderMapEntry env (oldBinder, newBinder) = do
791 let oldBinder' = zonkIdOcc env oldBinder
792 newBinder' <- zonkIdBndr env newBinder
793 return (oldBinder', newBinder')
795 zonkStmt env (LetStmt binds)
796 = zonkLocalBinds env binds `thenM` \ (env1, new_binds) ->
797 returnM (env1, LetStmt new_binds)
799 zonkStmt env (BindStmt pat expr bind_op fail_op)
800 = do { new_expr <- zonkLExpr env expr
801 ; (env1, new_pat) <- zonkPat env pat
802 ; new_bind <- zonkExpr env bind_op
803 ; new_fail <- zonkExpr env fail_op
804 ; return (env1, BindStmt new_pat new_expr new_bind new_fail) }
806 zonkMaybeLExpr :: ZonkEnv -> Maybe (LHsExpr TcId) -> TcM (Maybe (LHsExpr Id))
807 zonkMaybeLExpr _ Nothing = return Nothing
808 zonkMaybeLExpr env (Just e) = (zonkLExpr env e) >>= (return . Just)
811 -------------------------------------------------------------------------
812 zonkRecFields :: ZonkEnv -> HsRecordBinds TcId -> TcM (HsRecordBinds TcId)
813 zonkRecFields env (HsRecFields flds dd)
814 = do { flds' <- mappM zonk_rbind flds
815 ; return (HsRecFields flds' dd) }
818 = do { new_id <- wrapLocM (zonkIdBndr env) (hsRecFieldId fld)
819 ; new_expr <- zonkLExpr env (hsRecFieldArg fld)
820 ; return (fld { hsRecFieldId = new_id, hsRecFieldArg = new_expr }) }
822 -------------------------------------------------------------------------
823 mapIPNameTc :: (a -> TcM b) -> IPName a -> TcM (IPName b)
824 mapIPNameTc f (IPName n) = f n `thenM` \ r -> returnM (IPName r)
828 %************************************************************************
830 \subsection[BackSubst-Pats]{Patterns}
832 %************************************************************************
835 zonkPat :: ZonkEnv -> OutPat TcId -> TcM (ZonkEnv, OutPat Id)
836 -- Extend the environment as we go, because it's possible for one
837 -- pattern to bind something that is used in another (inside or
839 zonkPat env pat = wrapLocSndM (zonk_pat env) pat
841 zonk_pat :: ZonkEnv -> Pat TcId -> TcM (ZonkEnv, Pat Id)
842 zonk_pat env (ParPat p)
843 = do { (env', p') <- zonkPat env p
844 ; return (env', ParPat p') }
846 zonk_pat env (WildPat ty)
847 = do { ty' <- zonkTcTypeToType env ty
848 ; return (env, WildPat ty') }
850 zonk_pat env (VarPat v)
851 = do { v' <- zonkIdBndr env v
852 ; return (extendZonkEnv1 env v', VarPat v') }
854 zonk_pat env (LazyPat pat)
855 = do { (env', pat') <- zonkPat env pat
856 ; return (env', LazyPat pat') }
858 zonk_pat env (BangPat pat)
859 = do { (env', pat') <- zonkPat env pat
860 ; return (env', BangPat pat') }
862 zonk_pat env (AsPat (L loc v) pat)
863 = do { v' <- zonkIdBndr env v
864 ; (env', pat') <- zonkPat (extendZonkEnv1 env v') pat
865 ; return (env', AsPat (L loc v') pat') }
867 zonk_pat env (ViewPat expr pat ty)
868 = do { expr' <- zonkLExpr env expr
869 ; (env', pat') <- zonkPat env pat
870 ; ty' <- zonkTcTypeToType env ty
871 ; return (env', ViewPat expr' pat' ty') }
873 zonk_pat env (ListPat pats ty)
874 = do { ty' <- zonkTcTypeToType env ty
875 ; (env', pats') <- zonkPats env pats
876 ; return (env', ListPat pats' ty') }
878 zonk_pat env (PArrPat pats ty)
879 = do { ty' <- zonkTcTypeToType env ty
880 ; (env', pats') <- zonkPats env pats
881 ; return (env', PArrPat pats' ty') }
883 zonk_pat env (TuplePat pats boxed ty)
884 = do { ty' <- zonkTcTypeToType env ty
885 ; (env', pats') <- zonkPats env pats
886 ; return (env', TuplePat pats' boxed ty') }
888 zonk_pat env p@(ConPatOut { pat_ty = ty, pat_dicts = evs, pat_binds = binds, pat_args = args })
889 = ASSERT( all isImmutableTyVar (pat_tvs p) )
890 do { new_ty <- zonkTcTypeToType env ty
891 ; (env1, new_evs) <- zonkEvBndrsX env evs
892 ; (env2, new_binds) <- zonkTcEvBinds env1 binds
893 ; (env', new_args) <- zonkConStuff env2 args
894 ; returnM (env', p { pat_ty = new_ty, pat_dicts = new_evs,
895 pat_binds = new_binds, pat_args = new_args }) }
897 zonk_pat env (LitPat lit) = return (env, LitPat lit)
899 zonk_pat env (SigPatOut pat ty)
900 = do { ty' <- zonkTcTypeToType env ty
901 ; (env', pat') <- zonkPat env pat
902 ; return (env', SigPatOut pat' ty') }
904 zonk_pat env (NPat lit mb_neg eq_expr)
905 = do { lit' <- zonkOverLit env lit
906 ; mb_neg' <- fmapMaybeM (zonkExpr env) mb_neg
907 ; eq_expr' <- zonkExpr env eq_expr
908 ; return (env, NPat lit' mb_neg' eq_expr') }
910 zonk_pat env (NPlusKPat (L loc n) lit e1 e2)
911 = do { n' <- zonkIdBndr env n
912 ; lit' <- zonkOverLit env lit
913 ; e1' <- zonkExpr env e1
914 ; e2' <- zonkExpr env e2
915 ; return (extendZonkEnv1 env n', NPlusKPat (L loc n') lit' e1' e2') }
917 zonk_pat env (CoPat co_fn pat ty)
918 = do { (env', co_fn') <- zonkCoFn env co_fn
919 ; (env'', pat') <- zonkPat env' (noLoc pat)
920 ; ty' <- zonkTcTypeToType env'' ty
921 ; return (env'', CoPat co_fn' (unLoc pat') ty') }
923 zonk_pat _ pat = pprPanic "zonk_pat" (ppr pat)
925 ---------------------------
926 zonkConStuff :: ZonkEnv
927 -> HsConDetails (OutPat TcId) (HsRecFields id (OutPat TcId))
929 HsConDetails (OutPat Id) (HsRecFields id (OutPat Id)))
930 zonkConStuff env (PrefixCon pats)
931 = do { (env', pats') <- zonkPats env pats
932 ; return (env', PrefixCon pats') }
934 zonkConStuff env (InfixCon p1 p2)
935 = do { (env1, p1') <- zonkPat env p1
936 ; (env', p2') <- zonkPat env1 p2
937 ; return (env', InfixCon p1' p2') }
939 zonkConStuff env (RecCon (HsRecFields rpats dd))
940 = do { (env', pats') <- zonkPats env (map hsRecFieldArg rpats)
941 ; let rpats' = zipWith (\rp p' -> rp { hsRecFieldArg = p' }) rpats pats'
942 ; returnM (env', RecCon (HsRecFields rpats' dd)) }
943 -- Field selectors have declared types; hence no zonking
945 ---------------------------
946 zonkPats :: ZonkEnv -> [OutPat TcId] -> TcM (ZonkEnv, [OutPat Id])
947 zonkPats env [] = return (env, [])
948 zonkPats env (pat:pats) = do { (env1, pat') <- zonkPat env pat
949 ; (env', pats') <- zonkPats env1 pats
950 ; return (env', pat':pats') }
953 %************************************************************************
955 \subsection[BackSubst-Foreign]{Foreign exports}
957 %************************************************************************
961 zonkForeignExports :: ZonkEnv -> [LForeignDecl TcId] -> TcM [LForeignDecl Id]
962 zonkForeignExports env ls = mappM (wrapLocM (zonkForeignExport env)) ls
964 zonkForeignExport :: ZonkEnv -> ForeignDecl TcId -> TcM (ForeignDecl Id)
965 zonkForeignExport env (ForeignExport i _hs_ty spec) =
966 returnM (ForeignExport (fmap (zonkIdOcc env) i) undefined spec)
967 zonkForeignExport _ for_imp
968 = returnM for_imp -- Foreign imports don't need zonking
972 zonkRules :: ZonkEnv -> [LRuleDecl TcId] -> TcM [LRuleDecl Id]
973 zonkRules env rs = mappM (wrapLocM (zonkRule env)) rs
975 zonkRule :: ZonkEnv -> RuleDecl TcId -> TcM (RuleDecl Id)
976 zonkRule env (HsRule name act (vars{-::[RuleBndr TcId]-}) lhs fv_lhs rhs fv_rhs)
977 = do { (env_rhs, new_bndrs) <- mapAccumLM zonk_bndr env vars
979 ; unbound_tv_set <- newMutVar emptyVarSet
980 ; let env_lhs = setZonkType env_rhs (zonkTypeCollecting unbound_tv_set)
981 -- We need to gather the type variables mentioned on the LHS so we can
982 -- quantify over them. Example:
988 -- {-# RULES "myrule" foo C = 1 #-}
990 -- After type checking the LHS becomes (foo a (C a))
991 -- and we do not want to zap the unbound tyvar 'a' to (), because
992 -- that limits the applicability of the rule. Instead, we
993 -- want to quantify over it!
995 -- It's easiest to find the free tyvars here. Attempts to do so earlier
996 -- are tiresome, because (a) the data type is big and (b) finding the
997 -- free type vars of an expression is necessarily monadic operation.
998 -- (consider /\a -> f @ b, where b is side-effected to a)
1000 ; new_lhs <- zonkLExpr env_lhs lhs
1001 ; new_rhs <- zonkLExpr env_rhs rhs
1003 ; unbound_tvs <- readMutVar unbound_tv_set
1004 ; let final_bndrs :: [RuleBndr Var]
1005 final_bndrs = map (RuleBndr . noLoc) (varSetElems unbound_tvs) ++ new_bndrs
1007 ; return (HsRule name act final_bndrs new_lhs fv_lhs new_rhs fv_rhs) }
1009 zonk_bndr env (RuleBndr (L loc v))
1010 = do { (env', v') <- zonk_it env v; return (env', RuleBndr (L loc v')) }
1011 zonk_bndr _ (RuleBndrSig {}) = panic "zonk_bndr RuleBndrSig"
1014 | isId v = do { v' <- zonkIdBndr env v; return (extendZonkEnv1 env v', v') }
1015 | isCoVar v = do { v' <- zonkEvBndr env v; return (extendZonkEnv1 env v', v') }
1016 | otherwise = ASSERT( isImmutableTyVar v) return (env, v)
1020 %************************************************************************
1022 Constraints and evidence
1024 %************************************************************************
1027 zonkEvTerm :: ZonkEnv -> EvTerm -> TcM EvTerm
1028 zonkEvTerm env (EvId v) = ASSERT2( isId v, ppr v )
1029 return (EvId (zonkIdOcc env v))
1030 zonkEvTerm env (EvCoercion co) = do { co' <- zonkTcTypeToType env co
1031 ; return (EvCoercion co') }
1032 zonkEvTerm env (EvCast v co) = ASSERT( isId v)
1033 do { co' <- zonkTcTypeToType env co
1034 ; return (EvCast (zonkIdOcc env v) co') }
1035 zonkEvTerm env (EvSuperClass d n) = return (EvSuperClass (zonkIdOcc env d) n)
1036 zonkEvTerm env (EvDFunApp df tys tms)
1037 = do { tys' <- zonkTcTypeToTypes env tys
1038 ; let tms' = map (zonkEvVarOcc env) tms
1039 ; return (EvDFunApp (zonkIdOcc env df) tys' tms') }
1041 zonkTcEvBinds :: ZonkEnv -> TcEvBinds -> TcM (ZonkEnv, TcEvBinds)
1042 zonkTcEvBinds env (TcEvBinds var) = do { (env', bs') <- zonkEvBindsVar env var
1043 ; return (env', EvBinds bs') }
1044 zonkTcEvBinds env (EvBinds bs) = do { (env', bs') <- zonkEvBinds env bs
1045 ; return (env', EvBinds bs') }
1047 zonkEvBindsVar :: ZonkEnv -> EvBindsVar -> TcM (ZonkEnv, Bag EvBind)
1048 zonkEvBindsVar env (EvBindsVar ref _) = do { bs <- readMutVar ref
1049 ; zonkEvBinds env (evBindMapBinds bs) }
1051 zonkEvBinds :: ZonkEnv -> Bag EvBind -> TcM (ZonkEnv, Bag EvBind)
1052 zonkEvBinds env binds
1053 = fixM (\ ~( _, new_binds) -> do
1054 { let env1 = extendZonkEnv env (collect_ev_bndrs new_binds)
1055 ; binds' <- mapBagM (zonkEvBind env1) binds
1056 ; return (env1, binds') })
1058 collect_ev_bndrs :: Bag EvBind -> [EvVar]
1059 collect_ev_bndrs = foldrBag add []
1060 add (EvBind var _) vars = var : vars
1062 zonkEvBind :: ZonkEnv -> EvBind -> TcM EvBind
1063 zonkEvBind env (EvBind var term)
1064 = do { var' <- zonkEvBndr env var
1065 ; term' <- zonkEvTerm env term
1066 ; return (EvBind var' term') }
1069 %************************************************************************
1073 %************************************************************************
1076 zonkTcTypeToType :: ZonkEnv -> TcType -> TcM Type
1077 zonkTcTypeToType (ZonkEnv zonk_ty _) ty = zonk_ty ty
1079 zonkTcTypeToTypes :: ZonkEnv -> [TcType] -> TcM [Type]
1080 zonkTcTypeToTypes env tys = mapM (zonkTcTypeToType env) tys
1082 zonkTypeCollecting :: TcRef TyVarSet -> TcType -> TcM Type
1083 -- This variant collects unbound type variables in a mutable variable
1084 zonkTypeCollecting unbound_tv_set
1085 = zonkType (mkZonkTcTyVar zonk_unbound_tyvar)
1087 zonk_unbound_tyvar tv
1088 = do { tv' <- zonkQuantifiedTyVar tv
1089 ; tv_set <- readMutVar unbound_tv_set
1090 ; writeMutVar unbound_tv_set (extendVarSet tv_set tv')
1091 ; return (mkTyVarTy tv') }
1093 zonkTypeZapping :: TcType -> TcM Type
1094 -- This variant is used for everything except the LHS of rules
1095 -- It zaps unbound type variables to (), or some other arbitrary type
1097 = zonkType (mkZonkTcTyVar zonk_unbound_tyvar) ty
1099 -- Zonk a mutable but unbound type variable to an arbitrary type
1100 -- We know it's unbound even though we don't carry an environment,
1101 -- because at the binding site for a type variable we bind the
1102 -- mutable tyvar to a fresh immutable one. So the mutable store
1103 -- plays the role of an environment. If we come across a mutable
1104 -- type variable that isn't so bound, it must be completely free.
1105 zonk_unbound_tyvar tv = do { let ty = anyTypeOfKind (tyVarKind tv)
1106 ; writeMetaTyVar tv ty