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 (VarPatOut var _) = idType var
86 hsPatType (BangPat pat) = hsLPatType pat
87 hsPatType (LazyPat pat) = hsLPatType pat
88 hsPatType (LitPat lit) = hsLitType lit
89 hsPatType (AsPat var _) = idType (unLoc var)
90 hsPatType (ViewPat _ _ ty) = ty
91 hsPatType (ListPat _ ty) = mkListTy ty
92 hsPatType (PArrPat _ ty) = mkPArrTy ty
93 hsPatType (TuplePat _ _ ty) = ty
94 hsPatType (ConPatOut { pat_ty = ty }) = ty
95 hsPatType (SigPatOut _ ty) = ty
96 hsPatType (NPat lit _ _) = overLitType lit
97 hsPatType (NPlusKPat id _ _ _) = idType (unLoc id)
98 hsPatType (CoPat _ _ ty) = ty
99 hsPatType p = pprPanic "hsPatType" (ppr p)
101 hsLitType :: HsLit -> TcType
102 hsLitType (HsChar _) = charTy
103 hsLitType (HsCharPrim _) = charPrimTy
104 hsLitType (HsString _) = stringTy
105 hsLitType (HsStringPrim _) = addrPrimTy
106 hsLitType (HsInt _) = intTy
107 hsLitType (HsIntPrim _) = intPrimTy
108 hsLitType (HsWordPrim _) = wordPrimTy
109 hsLitType (HsInteger _ ty) = ty
110 hsLitType (HsRat _ ty) = ty
111 hsLitType (HsFloatPrim _) = floatPrimTy
112 hsLitType (HsDoublePrim _) = doublePrimTy
115 Overloaded literals. Here mainly becuase it uses isIntTy etc
118 shortCutLit :: OverLitVal -> TcType -> Maybe (HsExpr TcId)
119 shortCutLit (HsIntegral i) ty
120 | isIntTy ty && inIntRange i = Just (HsLit (HsInt i))
121 | isWordTy ty && inWordRange i = Just (mkLit wordDataCon (HsWordPrim i))
122 | isIntegerTy ty = Just (HsLit (HsInteger i ty))
123 | otherwise = shortCutLit (HsFractional (fromInteger i)) ty
124 -- The 'otherwise' case is important
125 -- Consider (3 :: Float). Syntactically it looks like an IntLit,
126 -- so we'll call shortCutIntLit, but of course it's a float
127 -- This can make a big difference for programs with a lot of
128 -- literals, compiled without -O
130 shortCutLit (HsFractional f) ty
131 | isFloatTy ty = Just (mkLit floatDataCon (HsFloatPrim f))
132 | isDoubleTy ty = Just (mkLit doubleDataCon (HsDoublePrim f))
133 | otherwise = Nothing
135 shortCutLit (HsIsString s) ty
136 | isStringTy ty = Just (HsLit (HsString s))
137 | otherwise = Nothing
139 mkLit :: DataCon -> HsLit -> HsExpr Id
140 mkLit con lit = HsApp (nlHsVar (dataConWrapId con)) (nlHsLit lit)
142 ------------------------------
143 hsOverLitName :: OverLitVal -> Name
144 -- Get the canonical 'fromX' name for a particular OverLitVal
145 hsOverLitName (HsIntegral {}) = fromIntegerName
146 hsOverLitName (HsFractional {}) = fromRationalName
147 hsOverLitName (HsIsString {}) = fromStringName
150 %************************************************************************
152 \subsection[BackSubst-HsBinds]{Running a substitution over @HsBinds@}
154 %************************************************************************
157 -- zonkId is used *during* typechecking just to zonk the Id's type
158 zonkId :: TcId -> TcM TcId
160 = zonkTcType (idType id) `thenM` \ ty' ->
161 returnM (Id.setIdType id ty')
164 The rest of the zonking is done *after* typechecking.
165 The main zonking pass runs over the bindings
167 a) to convert TcTyVars to TyVars etc, dereferencing any bindings etc
168 b) convert unbound TcTyVar to Void
169 c) convert each TcId to an Id by zonking its type
171 The type variables are converted by binding mutable tyvars to immutable ones
172 and then zonking as normal.
174 The Ids are converted by binding them in the normal Tc envt; that
175 way we maintain sharing; eg an Id is zonked at its binding site and they
176 all occurrences of that Id point to the common zonked copy
178 It's all pretty boring stuff, because HsSyn is such a large type, and
179 the environment manipulation is tiresome.
182 data ZonkEnv = ZonkEnv (TcType -> TcM Type) -- How to zonk a type
183 (VarEnv Var) -- What variables are in scope
184 -- Maps an Id or EvVar to its zonked version; both have the same Name
185 -- Note that all evidence (coercion variables as well as dictionaries)
186 -- are kept in the ZonkEnv
187 -- Only *type* abstraction is done by side effect
188 -- Is only consulted lazily; hence knot-tying
190 emptyZonkEnv :: ZonkEnv
191 emptyZonkEnv = ZonkEnv zonkTypeZapping emptyVarEnv
193 extendZonkEnv :: ZonkEnv -> [Var] -> ZonkEnv
194 extendZonkEnv (ZonkEnv zonk_ty env) ids
195 = ZonkEnv zonk_ty (extendVarEnvList env [(id,id) | id <- ids])
197 extendZonkEnv1 :: ZonkEnv -> Var -> ZonkEnv
198 extendZonkEnv1 (ZonkEnv zonk_ty env) id
199 = ZonkEnv zonk_ty (extendVarEnv env id id)
201 setZonkType :: ZonkEnv -> (TcType -> TcM Type) -> ZonkEnv
202 setZonkType (ZonkEnv _ env) zonk_ty = ZonkEnv zonk_ty env
204 zonkEnvIds :: ZonkEnv -> [Id]
205 zonkEnvIds (ZonkEnv _ env) = varEnvElts env
207 zonkIdOcc :: ZonkEnv -> TcId -> Id
208 -- Ids defined in this module should be in the envt;
209 -- ignore others. (Actually, data constructors are also
210 -- not LocalVars, even when locally defined, but that is fine.)
211 -- (Also foreign-imported things aren't currently in the ZonkEnv;
212 -- that's ok because they don't need zonking.)
214 -- Actually, Template Haskell works in 'chunks' of declarations, and
215 -- an earlier chunk won't be in the 'env' that the zonking phase
216 -- carries around. Instead it'll be in the tcg_gbl_env, already fully
217 -- zonked. There's no point in looking it up there (except for error
218 -- checking), and it's not conveniently to hand; hence the simple
219 -- 'orElse' case in the LocalVar branch.
221 -- Even without template splices, in module Main, the checking of
222 -- 'main' is done as a separate chunk.
223 zonkIdOcc (ZonkEnv _zonk_ty env) id
224 | isLocalVar id = lookupVarEnv env id `orElse` id
227 zonkIdOccs :: ZonkEnv -> [TcId] -> [Id]
228 zonkIdOccs env ids = map (zonkIdOcc env) ids
230 -- zonkIdBndr is used *after* typechecking to get the Id's type
231 -- to its final form. The TyVarEnv give
232 zonkIdBndr :: ZonkEnv -> TcId -> TcM Id
234 = zonkTcTypeToType env (idType id) `thenM` \ ty' ->
235 returnM (Id.setIdType id ty')
237 zonkIdBndrs :: ZonkEnv -> [TcId] -> TcM [Id]
238 zonkIdBndrs env ids = mappM (zonkIdBndr env) ids
240 zonkTopBndrs :: [TcId] -> TcM [Id]
241 zonkTopBndrs ids = zonkIdBndrs emptyZonkEnv ids
243 zonkEvBndrsX :: ZonkEnv -> [EvVar] -> TcM (ZonkEnv, [Var])
244 zonkEvBndrsX = mapAccumLM zonkEvBndrX
246 zonkEvBndrX :: ZonkEnv -> EvVar -> TcM (ZonkEnv, EvVar)
247 -- Works for dictionaries and coercions
249 = do { var' <- zonkEvBndr env var
250 ; return (extendZonkEnv1 env var', var') }
252 zonkEvBndr :: ZonkEnv -> EvVar -> TcM EvVar
253 -- Works for dictionaries and coercions
254 -- Does not extend the ZonkEnv
256 = do { ty' <- zonkTcTypeToType env (varType var)
257 ; return (setVarType var ty') }
259 zonkEvVarOcc :: ZonkEnv -> EvVar -> EvVar
260 zonkEvVarOcc env v = zonkIdOcc env v
265 zonkTopExpr :: HsExpr TcId -> TcM (HsExpr Id)
266 zonkTopExpr e = zonkExpr emptyZonkEnv e
268 zonkTopLExpr :: LHsExpr TcId -> TcM (LHsExpr Id)
269 zonkTopLExpr e = zonkLExpr emptyZonkEnv e
271 zonkTopDecls :: Bag EvBind
272 -> LHsBinds TcId -> NameSet
273 -> [LRuleDecl TcId] -> [LForeignDecl TcId]
279 zonkTopDecls ev_binds binds sig_ns rules 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 ; fords' <- zonkForeignExports env2 fords
292 ; return (zonkEnvIds env2, ev_binds', binds', fords', rules') }
294 ---------------------------------------------
295 zonkLocalBinds :: ZonkEnv -> HsLocalBinds TcId -> TcM (ZonkEnv, HsLocalBinds Id)
296 zonkLocalBinds env EmptyLocalBinds
297 = return (env, EmptyLocalBinds)
299 zonkLocalBinds _ (HsValBinds (ValBindsIn {}))
300 = panic "zonkLocalBinds" -- Not in typechecker output
302 zonkLocalBinds env (HsValBinds vb@(ValBindsOut binds sigs))
303 = do { warn_missing_sigs <- doptM Opt_WarnMissingLocalSigs
304 ; let sig_warn | not warn_missing_sigs = noSigWarn
305 | otherwise = localSigWarn sig_ns
306 sig_ns = getTypeSigNames vb
307 ; (env1, new_binds) <- go env sig_warn binds
308 ; return (env1, HsValBinds (ValBindsOut new_binds sigs)) }
312 go env sig_warn ((r,b):bs)
313 = do { (env1, b') <- zonkRecMonoBinds env sig_warn b
314 ; (env2, bs') <- go env1 sig_warn bs
315 ; return (env2, (r,b'):bs') }
317 zonkLocalBinds env (HsIPBinds (IPBinds binds dict_binds))
318 = mappM (wrapLocM zonk_ip_bind) binds `thenM` \ new_binds ->
320 env1 = extendZonkEnv env [ipNameName n | L _ (IPBind n _) <- new_binds]
322 zonkTcEvBinds env1 dict_binds `thenM` \ (env2, new_dict_binds) ->
323 returnM (env2, HsIPBinds (IPBinds new_binds new_dict_binds))
325 zonk_ip_bind (IPBind n e)
326 = mapIPNameTc (zonkIdBndr env) n `thenM` \ n' ->
327 zonkLExpr env e `thenM` \ e' ->
328 returnM (IPBind n' e')
330 ---------------------------------------------
331 zonkRecMonoBinds :: ZonkEnv -> SigWarn -> LHsBinds TcId -> TcM (ZonkEnv, LHsBinds Id)
332 zonkRecMonoBinds env sig_warn binds
333 = fixM (\ ~(_, new_binds) -> do
334 { let env1 = extendZonkEnv env (collectHsBindsBinders new_binds)
335 ; binds' <- zonkMonoBinds env1 sig_warn binds
336 ; return (env1, binds') })
338 ---------------------------------------------
339 type SigWarn = Bool -> [Id] -> TcM ()
340 -- Missing-signature warning
341 -- The Bool is True for an AbsBinds, False otherwise
344 noSigWarn _ _ = return ()
346 topSigWarn :: NameSet -> SigWarn
347 topSigWarn sig_ns _ ids = mapM_ (topSigWarnId sig_ns) ids
349 topSigWarnId :: NameSet -> Id -> TcM ()
350 -- The NameSet is the Ids that *lack* a signature
351 -- We have to do it this way round because there are
352 -- lots of top-level bindings that are generated by GHC
353 -- and that don't have signatures
354 topSigWarnId sig_ns id
355 | idName id `elemNameSet` sig_ns = warnMissingSig msg id
356 | otherwise = return ()
358 msg = ptext (sLit "Top-level binding with no type signature:")
360 localSigWarn :: NameSet -> SigWarn
361 localSigWarn sig_ns is_abs_bind ids
362 | not is_abs_bind = return ()
363 | otherwise = mapM_ (localSigWarnId sig_ns) ids
365 localSigWarnId :: NameSet -> Id -> TcM ()
366 -- NameSet are the Ids that *have* type signatures
367 localSigWarnId sig_ns id
368 | not (isSigmaTy (idType id)) = return ()
369 | idName id `elemNameSet` sig_ns = return ()
370 | otherwise = warnMissingSig msg id
372 msg = ptext (sLit "Polymophic local binding with no type signature:")
374 warnMissingSig :: SDoc -> Id -> TcM ()
375 warnMissingSig msg id
376 = do { env0 <- tcInitTidyEnv
377 ; let (env1, tidy_ty) = tidyOpenType env0 (idType id)
378 ; addWarnTcM (env1, mk_msg tidy_ty) }
380 mk_msg ty = sep [ msg, nest 2 $ pprHsVar (idName id) <+> dcolon <+> ppr ty ]
382 ---------------------------------------------
383 zonkMonoBinds :: ZonkEnv -> SigWarn -> LHsBinds TcId -> TcM (LHsBinds Id)
384 zonkMonoBinds env sig_warn binds = mapBagM (wrapLocM (zonk_bind env sig_warn)) binds
386 zonk_bind :: ZonkEnv -> SigWarn -> HsBind TcId -> TcM (HsBind Id)
387 zonk_bind env sig_warn bind@(PatBind { pat_lhs = pat, pat_rhs = grhss, pat_rhs_ty = ty})
388 = do { (_env, new_pat) <- zonkPat env pat -- Env already extended
389 ; sig_warn False (collectPatBinders new_pat)
390 ; new_grhss <- zonkGRHSs env grhss
391 ; new_ty <- zonkTcTypeToType env ty
392 ; return (bind { pat_lhs = new_pat, pat_rhs = new_grhss, pat_rhs_ty = new_ty }) }
394 zonk_bind env sig_warn (VarBind { var_id = var, var_rhs = expr, var_inline = inl })
395 = do { new_var <- zonkIdBndr env var
396 ; sig_warn False [new_var]
397 ; new_expr <- zonkLExpr env expr
398 ; return (VarBind { var_id = new_var, var_rhs = new_expr, var_inline = inl }) }
400 zonk_bind env sig_warn bind@(FunBind { fun_id = L loc var, fun_matches = ms
401 , fun_co_fn = co_fn })
402 = do { new_var <- zonkIdBndr env var
403 ; sig_warn False [new_var]
404 ; (env1, new_co_fn) <- zonkCoFn env co_fn
405 ; new_ms <- zonkMatchGroup env1 ms
406 ; return (bind { fun_id = L loc new_var, fun_matches = new_ms
407 , fun_co_fn = new_co_fn }) }
409 zonk_bind env sig_warn (AbsBinds { abs_tvs = tyvars, abs_ev_vars = evs
410 , abs_ev_binds = ev_binds
411 , abs_exports = exports
412 , abs_binds = val_binds })
413 = ASSERT( all isImmutableTyVar tyvars )
414 do { (env1, new_evs) <- zonkEvBndrsX env evs
415 ; (env2, new_ev_binds) <- zonkTcEvBinds env1 ev_binds
416 ; (new_val_bind, new_exports) <- fixM $ \ ~(new_val_binds, _) ->
417 do { let env3 = extendZonkEnv env2 (collectHsBindsBinders new_val_binds)
418 ; new_val_binds <- zonkMonoBinds env3 noSigWarn val_binds
419 ; new_exports <- mapM (zonkExport env3) exports
420 ; return (new_val_binds, new_exports) }
421 ; sig_warn True [b | (_,b,_,_) <- new_exports]
422 ; return (AbsBinds { abs_tvs = tyvars, abs_ev_vars = new_evs, abs_ev_binds = new_ev_binds
423 , abs_exports = new_exports, abs_binds = new_val_bind }) }
425 zonkExport env (tyvars, global, local, prags)
426 -- The tyvars are already zonked
427 = zonkIdBndr env global `thenM` \ new_global ->
428 zonkSpecPrags env prags `thenM` \ new_prags ->
429 returnM (tyvars, new_global, zonkIdOcc env local, new_prags)
431 zonkSpecPrags :: ZonkEnv -> TcSpecPrags -> TcM TcSpecPrags
432 zonkSpecPrags _ IsDefaultMethod = return IsDefaultMethod
433 zonkSpecPrags env (SpecPrags ps) = do { ps' <- mapM zonk_prag ps
434 ; return (SpecPrags ps') }
436 zonk_prag (L loc (SpecPrag co_fn inl))
437 = do { (_, co_fn') <- zonkCoFn env co_fn
438 ; return (L loc (SpecPrag co_fn' inl)) }
441 %************************************************************************
443 \subsection[BackSubst-Match-GRHSs]{Match and GRHSs}
445 %************************************************************************
448 zonkMatchGroup :: ZonkEnv -> MatchGroup TcId-> TcM (MatchGroup Id)
449 zonkMatchGroup env (MatchGroup ms ty)
450 = do { ms' <- mapM (zonkMatch env) ms
451 ; ty' <- zonkTcTypeToType env ty
452 ; return (MatchGroup ms' ty') }
454 zonkMatch :: ZonkEnv -> LMatch TcId-> TcM (LMatch Id)
455 zonkMatch env (L loc (Match pats _ grhss))
456 = do { (env1, new_pats) <- zonkPats env pats
457 ; new_grhss <- zonkGRHSs env1 grhss
458 ; return (L loc (Match new_pats Nothing new_grhss)) }
460 -------------------------------------------------------------------------
461 zonkGRHSs :: ZonkEnv -> GRHSs TcId -> TcM (GRHSs Id)
463 zonkGRHSs env (GRHSs grhss binds)
464 = zonkLocalBinds env binds `thenM` \ (new_env, new_binds) ->
466 zonk_grhs (GRHS guarded rhs)
467 = zonkStmts new_env guarded `thenM` \ (env2, new_guarded) ->
468 zonkLExpr env2 rhs `thenM` \ new_rhs ->
469 returnM (GRHS new_guarded new_rhs)
471 mappM (wrapLocM zonk_grhs) grhss `thenM` \ new_grhss ->
472 returnM (GRHSs new_grhss new_binds)
475 %************************************************************************
477 \subsection[BackSubst-HsExpr]{Running a zonkitution over a TypeCheckedExpr}
479 %************************************************************************
482 zonkLExprs :: ZonkEnv -> [LHsExpr TcId] -> TcM [LHsExpr Id]
483 zonkLExpr :: ZonkEnv -> LHsExpr TcId -> TcM (LHsExpr Id)
484 zonkExpr :: ZonkEnv -> HsExpr TcId -> TcM (HsExpr Id)
486 zonkLExprs env exprs = mappM (zonkLExpr env) exprs
487 zonkLExpr env expr = wrapLocM (zonkExpr env) expr
489 zonkExpr env (HsVar id)
490 = returnM (HsVar (zonkIdOcc env id))
492 zonkExpr env (HsIPVar id)
493 = returnM (HsIPVar (mapIPName (zonkIdOcc env) id))
495 zonkExpr env (HsLit (HsRat f ty))
496 = zonkTcTypeToType env ty `thenM` \ new_ty ->
497 returnM (HsLit (HsRat f new_ty))
499 zonkExpr _ (HsLit lit)
500 = returnM (HsLit lit)
502 zonkExpr env (HsOverLit lit)
503 = do { lit' <- zonkOverLit env lit
504 ; return (HsOverLit lit') }
506 zonkExpr env (HsLam matches)
507 = zonkMatchGroup env matches `thenM` \ new_matches ->
508 returnM (HsLam new_matches)
510 zonkExpr env (HsApp e1 e2)
511 = zonkLExpr env e1 `thenM` \ new_e1 ->
512 zonkLExpr env e2 `thenM` \ new_e2 ->
513 returnM (HsApp new_e1 new_e2)
515 zonkExpr env (HsBracketOut body bs)
516 = mappM zonk_b bs `thenM` \ bs' ->
517 returnM (HsBracketOut body bs')
519 zonk_b (n,e) = zonkLExpr env e `thenM` \ e' ->
522 zonkExpr _ (HsSpliceE s) = WARN( True, ppr s ) -- Should not happen
523 returnM (HsSpliceE s)
525 zonkExpr env (OpApp e1 op fixity e2)
526 = zonkLExpr env e1 `thenM` \ new_e1 ->
527 zonkLExpr env op `thenM` \ new_op ->
528 zonkLExpr env e2 `thenM` \ new_e2 ->
529 returnM (OpApp new_e1 new_op fixity new_e2)
531 zonkExpr env (NegApp expr op)
532 = zonkLExpr env expr `thenM` \ new_expr ->
533 zonkExpr env op `thenM` \ new_op ->
534 returnM (NegApp new_expr new_op)
536 zonkExpr env (HsPar e)
537 = zonkLExpr env e `thenM` \new_e ->
538 returnM (HsPar new_e)
540 zonkExpr env (SectionL expr op)
541 = zonkLExpr env expr `thenM` \ new_expr ->
542 zonkLExpr env op `thenM` \ new_op ->
543 returnM (SectionL new_expr new_op)
545 zonkExpr env (SectionR op expr)
546 = zonkLExpr env op `thenM` \ new_op ->
547 zonkLExpr env expr `thenM` \ new_expr ->
548 returnM (SectionR new_op new_expr)
550 zonkExpr env (ExplicitTuple tup_args boxed)
551 = do { new_tup_args <- mapM zonk_tup_arg tup_args
552 ; return (ExplicitTuple new_tup_args boxed) }
554 zonk_tup_arg (Present e) = do { e' <- zonkLExpr env e; return (Present e') }
555 zonk_tup_arg (Missing t) = do { t' <- zonkTcTypeToType env t; return (Missing t') }
557 zonkExpr env (HsCase expr ms)
558 = zonkLExpr env expr `thenM` \ new_expr ->
559 zonkMatchGroup env ms `thenM` \ new_ms ->
560 returnM (HsCase new_expr new_ms)
562 zonkExpr env (HsIf e1 e2 e3)
563 = zonkLExpr env e1 `thenM` \ new_e1 ->
564 zonkLExpr env e2 `thenM` \ new_e2 ->
565 zonkLExpr env e3 `thenM` \ new_e3 ->
566 returnM (HsIf new_e1 new_e2 new_e3)
568 zonkExpr env (HsLet binds expr)
569 = zonkLocalBinds env binds `thenM` \ (new_env, new_binds) ->
570 zonkLExpr new_env expr `thenM` \ new_expr ->
571 returnM (HsLet new_binds new_expr)
573 zonkExpr env (HsDo do_or_lc stmts body ty)
574 = zonkStmts env stmts `thenM` \ (new_env, new_stmts) ->
575 zonkLExpr new_env body `thenM` \ new_body ->
576 zonkTcTypeToType env ty `thenM` \ new_ty ->
577 zonkDo env do_or_lc `thenM` \ new_do_or_lc ->
578 returnM (HsDo new_do_or_lc new_stmts new_body new_ty)
580 zonkExpr env (ExplicitList ty exprs)
581 = zonkTcTypeToType env ty `thenM` \ new_ty ->
582 zonkLExprs env exprs `thenM` \ new_exprs ->
583 returnM (ExplicitList new_ty new_exprs)
585 zonkExpr env (ExplicitPArr ty exprs)
586 = zonkTcTypeToType env ty `thenM` \ new_ty ->
587 zonkLExprs env exprs `thenM` \ new_exprs ->
588 returnM (ExplicitPArr new_ty new_exprs)
590 zonkExpr env (RecordCon data_con con_expr rbinds)
591 = do { new_con_expr <- zonkExpr env con_expr
592 ; new_rbinds <- zonkRecFields env rbinds
593 ; return (RecordCon data_con new_con_expr new_rbinds) }
595 zonkExpr env (RecordUpd expr rbinds cons in_tys out_tys)
596 = do { new_expr <- zonkLExpr env expr
597 ; new_in_tys <- mapM (zonkTcTypeToType env) in_tys
598 ; new_out_tys <- mapM (zonkTcTypeToType env) out_tys
599 ; new_rbinds <- zonkRecFields env rbinds
600 ; return (RecordUpd new_expr new_rbinds cons new_in_tys new_out_tys) }
602 zonkExpr env (ExprWithTySigOut e ty)
603 = do { e' <- zonkLExpr env e
604 ; return (ExprWithTySigOut e' ty) }
606 zonkExpr _ (ExprWithTySig _ _) = panic "zonkExpr env:ExprWithTySig"
608 zonkExpr env (ArithSeq expr info)
609 = zonkExpr env expr `thenM` \ new_expr ->
610 zonkArithSeq env info `thenM` \ new_info ->
611 returnM (ArithSeq new_expr new_info)
613 zonkExpr env (PArrSeq expr info)
614 = zonkExpr env expr `thenM` \ new_expr ->
615 zonkArithSeq env info `thenM` \ new_info ->
616 returnM (PArrSeq new_expr new_info)
618 zonkExpr env (HsSCC lbl expr)
619 = zonkLExpr env expr `thenM` \ new_expr ->
620 returnM (HsSCC lbl new_expr)
622 zonkExpr env (HsTickPragma info expr)
623 = zonkLExpr env expr `thenM` \ new_expr ->
624 returnM (HsTickPragma info new_expr)
626 -- hdaume: core annotations
627 zonkExpr env (HsCoreAnn lbl expr)
628 = zonkLExpr env expr `thenM` \ new_expr ->
629 returnM (HsCoreAnn lbl new_expr)
631 -- arrow notation extensions
632 zonkExpr env (HsProc pat body)
633 = do { (env1, new_pat) <- zonkPat env pat
634 ; new_body <- zonkCmdTop env1 body
635 ; return (HsProc new_pat new_body) }
637 zonkExpr env (HsArrApp e1 e2 ty ho rl)
638 = zonkLExpr env e1 `thenM` \ new_e1 ->
639 zonkLExpr env e2 `thenM` \ new_e2 ->
640 zonkTcTypeToType env ty `thenM` \ new_ty ->
641 returnM (HsArrApp new_e1 new_e2 new_ty ho rl)
643 zonkExpr env (HsArrForm op fixity args)
644 = zonkLExpr env op `thenM` \ new_op ->
645 mappM (zonkCmdTop env) args `thenM` \ new_args ->
646 returnM (HsArrForm new_op fixity new_args)
648 zonkExpr env (HsWrap co_fn expr)
649 = zonkCoFn env co_fn `thenM` \ (env1, new_co_fn) ->
650 zonkExpr env1 expr `thenM` \ new_expr ->
651 return (HsWrap new_co_fn new_expr)
653 zonkExpr _ expr = pprPanic "zonkExpr" (ppr expr)
655 zonkCmdTop :: ZonkEnv -> LHsCmdTop TcId -> TcM (LHsCmdTop Id)
656 zonkCmdTop env cmd = wrapLocM (zonk_cmd_top env) cmd
658 zonk_cmd_top :: ZonkEnv -> HsCmdTop TcId -> TcM (HsCmdTop Id)
659 zonk_cmd_top env (HsCmdTop cmd stack_tys ty ids)
660 = zonkLExpr env cmd `thenM` \ new_cmd ->
661 zonkTcTypeToTypes env stack_tys `thenM` \ new_stack_tys ->
662 zonkTcTypeToType env ty `thenM` \ new_ty ->
663 mapSndM (zonkExpr env) ids `thenM` \ new_ids ->
664 returnM (HsCmdTop new_cmd new_stack_tys new_ty new_ids)
666 -------------------------------------------------------------------------
667 zonkCoFn :: ZonkEnv -> HsWrapper -> TcM (ZonkEnv, HsWrapper)
668 zonkCoFn env WpHole = return (env, WpHole)
669 zonkCoFn env (WpCompose c1 c2) = do { (env1, c1') <- zonkCoFn env c1
670 ; (env2, c2') <- zonkCoFn env1 c2
671 ; return (env2, WpCompose c1' c2') }
672 zonkCoFn env (WpCast co) = do { co' <- zonkTcTypeToType env co
673 ; return (env, WpCast co') }
674 zonkCoFn env (WpEvLam ev) = do { (env', ev') <- zonkEvBndrX env ev
675 ; return (env', WpEvLam ev') }
676 zonkCoFn env (WpEvApp arg) = do { arg' <- zonkEvTerm env arg
677 ; return (env, WpEvApp arg') }
678 zonkCoFn env (WpTyLam tv) = ASSERT( isImmutableTyVar tv )
679 return (env, WpTyLam tv)
680 zonkCoFn env (WpTyApp ty) = do { ty' <- zonkTcTypeToType env ty
681 ; return (env, WpTyApp ty') }
682 zonkCoFn env (WpLet bs) = do { (env1, bs') <- zonkTcEvBinds env bs
683 ; return (env1, WpLet bs') }
685 -------------------------------------------------------------------------
686 zonkDo :: ZonkEnv -> HsStmtContext Name -> TcM (HsStmtContext Name)
687 -- Only used for 'do', so the only Ids are in a MDoExpr table
688 zonkDo env (MDoExpr tbl) = do { tbl' <- mapSndM (zonkExpr env) tbl
689 ; return (MDoExpr tbl') }
690 zonkDo _ do_or_lc = return do_or_lc
692 -------------------------------------------------------------------------
693 zonkOverLit :: ZonkEnv -> HsOverLit TcId -> TcM (HsOverLit Id)
694 zonkOverLit env lit@(OverLit { ol_witness = e, ol_type = ty })
695 = do { ty' <- zonkTcTypeToType env ty
696 ; e' <- zonkExpr env e
697 ; return (lit { ol_witness = e', ol_type = ty' }) }
699 -------------------------------------------------------------------------
700 zonkArithSeq :: ZonkEnv -> ArithSeqInfo TcId -> TcM (ArithSeqInfo Id)
702 zonkArithSeq env (From e)
703 = zonkLExpr env e `thenM` \ new_e ->
706 zonkArithSeq env (FromThen e1 e2)
707 = zonkLExpr env e1 `thenM` \ new_e1 ->
708 zonkLExpr env e2 `thenM` \ new_e2 ->
709 returnM (FromThen new_e1 new_e2)
711 zonkArithSeq env (FromTo e1 e2)
712 = zonkLExpr env e1 `thenM` \ new_e1 ->
713 zonkLExpr env e2 `thenM` \ new_e2 ->
714 returnM (FromTo new_e1 new_e2)
716 zonkArithSeq env (FromThenTo e1 e2 e3)
717 = zonkLExpr env e1 `thenM` \ new_e1 ->
718 zonkLExpr env e2 `thenM` \ new_e2 ->
719 zonkLExpr env e3 `thenM` \ new_e3 ->
720 returnM (FromThenTo new_e1 new_e2 new_e3)
723 -------------------------------------------------------------------------
724 zonkStmts :: ZonkEnv -> [LStmt TcId] -> TcM (ZonkEnv, [LStmt Id])
725 zonkStmts env [] = return (env, [])
726 zonkStmts env (s:ss) = do { (env1, s') <- wrapLocSndM (zonkStmt env) s
727 ; (env2, ss') <- zonkStmts env1 ss
728 ; return (env2, s' : ss') }
730 zonkStmt :: ZonkEnv -> Stmt TcId -> TcM (ZonkEnv, Stmt Id)
731 zonkStmt env (ParStmt stmts_w_bndrs)
732 = mappM zonk_branch stmts_w_bndrs `thenM` \ new_stmts_w_bndrs ->
734 new_binders = concat (map snd new_stmts_w_bndrs)
735 env1 = extendZonkEnv env new_binders
737 return (env1, ParStmt new_stmts_w_bndrs)
739 zonk_branch (stmts, bndrs) = zonkStmts env stmts `thenM` \ (env1, new_stmts) ->
740 returnM (new_stmts, zonkIdOccs env1 bndrs)
742 zonkStmt env (RecStmt { recS_stmts = segStmts, recS_later_ids = lvs, recS_rec_ids = rvs
743 , recS_ret_fn = ret_id, recS_mfix_fn = mfix_id, recS_bind_fn = bind_id
744 , recS_rec_rets = rets, recS_dicts = binds })
745 = do { new_rvs <- zonkIdBndrs env rvs
746 ; new_lvs <- zonkIdBndrs env lvs
747 ; new_ret_id <- zonkExpr env ret_id
748 ; new_mfix_id <- zonkExpr env mfix_id
749 ; new_bind_id <- zonkExpr env bind_id
750 ; let env1 = extendZonkEnv env new_rvs
751 ; (env2, new_segStmts) <- zonkStmts env1 segStmts
752 -- Zonk the ret-expressions in an envt that
753 -- has the polymorphic bindings in the envt
754 ; new_rets <- mapM (zonkExpr env2) rets
755 ; let env3 = extendZonkEnv env new_lvs -- Only the lvs are needed
756 ; (env4, new_binds) <- zonkTcEvBinds env3 binds
758 RecStmt { recS_stmts = new_segStmts, recS_later_ids = new_lvs
759 , recS_rec_ids = new_rvs, recS_ret_fn = new_ret_id
760 , recS_mfix_fn = new_mfix_id, recS_bind_fn = new_bind_id
761 , recS_rec_rets = new_rets, recS_dicts = new_binds }) }
763 zonkStmt env (ExprStmt expr then_op ty)
764 = zonkLExpr env expr `thenM` \ new_expr ->
765 zonkExpr env then_op `thenM` \ new_then ->
766 zonkTcTypeToType env ty `thenM` \ new_ty ->
767 returnM (env, ExprStmt new_expr new_then new_ty)
769 zonkStmt env (TransformStmt stmts binders usingExpr maybeByExpr)
770 = do { (env', stmts') <- zonkStmts env stmts
771 ; let binders' = zonkIdOccs env' binders
772 ; usingExpr' <- zonkLExpr env' usingExpr
773 ; maybeByExpr' <- zonkMaybeLExpr env' maybeByExpr
774 ; return (env', TransformStmt stmts' binders' usingExpr' maybeByExpr') }
776 zonkStmt env (GroupStmt stmts binderMap by using)
777 = do { (env', stmts') <- zonkStmts env stmts
778 ; binderMap' <- mappM (zonkBinderMapEntry env') binderMap
779 ; by' <- fmapMaybeM (zonkLExpr env') by
780 ; using' <- fmapEitherM (zonkLExpr env) (zonkExpr env) using
781 ; let env'' = extendZonkEnv env' (map snd binderMap')
782 ; return (env'', GroupStmt stmts' binderMap' by' using') }
784 zonkBinderMapEntry env (oldBinder, newBinder) = do
785 let oldBinder' = zonkIdOcc env oldBinder
786 newBinder' <- zonkIdBndr env newBinder
787 return (oldBinder', newBinder')
789 zonkStmt env (LetStmt binds)
790 = zonkLocalBinds env binds `thenM` \ (env1, new_binds) ->
791 returnM (env1, LetStmt new_binds)
793 zonkStmt env (BindStmt pat expr bind_op fail_op)
794 = do { new_expr <- zonkLExpr env expr
795 ; (env1, new_pat) <- zonkPat env pat
796 ; new_bind <- zonkExpr env bind_op
797 ; new_fail <- zonkExpr env fail_op
798 ; return (env1, BindStmt new_pat new_expr new_bind new_fail) }
800 zonkMaybeLExpr :: ZonkEnv -> Maybe (LHsExpr TcId) -> TcM (Maybe (LHsExpr Id))
801 zonkMaybeLExpr _ Nothing = return Nothing
802 zonkMaybeLExpr env (Just e) = (zonkLExpr env e) >>= (return . Just)
805 -------------------------------------------------------------------------
806 zonkRecFields :: ZonkEnv -> HsRecordBinds TcId -> TcM (HsRecordBinds TcId)
807 zonkRecFields env (HsRecFields flds dd)
808 = do { flds' <- mappM zonk_rbind flds
809 ; return (HsRecFields flds' dd) }
812 = do { new_id <- wrapLocM (zonkIdBndr env) (hsRecFieldId fld)
813 ; new_expr <- zonkLExpr env (hsRecFieldArg fld)
814 ; return (fld { hsRecFieldId = new_id, hsRecFieldArg = new_expr }) }
816 -------------------------------------------------------------------------
817 mapIPNameTc :: (a -> TcM b) -> IPName a -> TcM (IPName b)
818 mapIPNameTc f (IPName n) = f n `thenM` \ r -> returnM (IPName r)
822 %************************************************************************
824 \subsection[BackSubst-Pats]{Patterns}
826 %************************************************************************
829 zonkPat :: ZonkEnv -> OutPat TcId -> TcM (ZonkEnv, OutPat Id)
830 -- Extend the environment as we go, because it's possible for one
831 -- pattern to bind something that is used in another (inside or
833 zonkPat env pat = wrapLocSndM (zonk_pat env) pat
835 zonk_pat :: ZonkEnv -> Pat TcId -> TcM (ZonkEnv, Pat Id)
836 zonk_pat env (ParPat p)
837 = do { (env', p') <- zonkPat env p
838 ; return (env', ParPat p') }
840 zonk_pat env (WildPat ty)
841 = do { ty' <- zonkTcTypeToType env ty
842 ; return (env, WildPat ty') }
844 zonk_pat env (VarPat v)
845 = do { v' <- zonkIdBndr env v
846 ; return (extendZonkEnv1 env v', VarPat v') }
848 zonk_pat env (VarPatOut v binds)
849 = do { v' <- zonkIdBndr env v
850 ; (env', binds') <- zonkTcEvBinds (extendZonkEnv1 env v') binds
851 ; returnM (env', VarPatOut v' binds') }
853 zonk_pat env (LazyPat pat)
854 = do { (env', pat') <- zonkPat env pat
855 ; return (env', LazyPat pat') }
857 zonk_pat env (BangPat pat)
858 = do { (env', pat') <- zonkPat env pat
859 ; return (env', BangPat pat') }
861 zonk_pat env (AsPat (L loc v) pat)
862 = do { v' <- zonkIdBndr env v
863 ; (env', pat') <- zonkPat (extendZonkEnv1 env v') pat
864 ; return (env', AsPat (L loc v') pat') }
866 zonk_pat env (ViewPat expr pat ty)
867 = do { expr' <- zonkLExpr env expr
868 ; (env', pat') <- zonkPat env pat
869 ; ty' <- zonkTcTypeToType env ty
870 ; return (env', ViewPat expr' pat' ty') }
872 zonk_pat env (ListPat pats ty)
873 = do { ty' <- zonkTcTypeToType env ty
874 ; (env', pats') <- zonkPats env pats
875 ; return (env', ListPat pats' ty') }
877 zonk_pat env (PArrPat pats ty)
878 = do { ty' <- zonkTcTypeToType env ty
879 ; (env', pats') <- zonkPats env pats
880 ; return (env', PArrPat pats' ty') }
882 zonk_pat env (TuplePat pats boxed ty)
883 = do { ty' <- zonkTcTypeToType env ty
884 ; (env', pats') <- zonkPats env pats
885 ; return (env', TuplePat pats' boxed ty') }
887 zonk_pat env p@(ConPatOut { pat_ty = ty, pat_dicts = evs, pat_binds = binds, pat_args = args })
888 = ASSERT( all isImmutableTyVar (pat_tvs p) )
889 do { new_ty <- zonkTcTypeToType env ty
890 ; (env1, new_evs) <- zonkEvBndrsX env evs
891 ; (env2, new_binds) <- zonkTcEvBinds env1 binds
892 ; (env', new_args) <- zonkConStuff env2 args
893 ; returnM (env', p { pat_ty = new_ty, pat_dicts = new_evs,
894 pat_binds = new_binds, pat_args = new_args }) }
896 zonk_pat env (LitPat lit) = return (env, LitPat lit)
898 zonk_pat env (SigPatOut pat ty)
899 = do { ty' <- zonkTcTypeToType env ty
900 ; (env', pat') <- zonkPat env pat
901 ; return (env', SigPatOut pat' ty') }
903 zonk_pat env (NPat lit mb_neg eq_expr)
904 = do { lit' <- zonkOverLit env lit
905 ; mb_neg' <- case mb_neg of
906 Nothing -> return Nothing
907 Just neg -> do { neg' <- zonkExpr env neg
908 ; return (Just neg') }
909 ; eq_expr' <- zonkExpr env eq_expr
910 ; return (env, NPat lit' mb_neg' eq_expr') }
912 zonk_pat env (NPlusKPat (L loc n) lit e1 e2)
913 = do { n' <- zonkIdBndr env n
914 ; lit' <- zonkOverLit env lit
915 ; e1' <- zonkExpr env e1
916 ; e2' <- zonkExpr env e2
917 ; return (extendZonkEnv1 env n', NPlusKPat (L loc n') lit' e1' e2') }
919 zonk_pat env (CoPat co_fn pat ty)
920 = do { (env', co_fn') <- zonkCoFn env co_fn
921 ; (env'', pat') <- zonkPat env' (noLoc pat)
922 ; ty' <- zonkTcTypeToType env'' ty
923 ; return (env'', CoPat co_fn' (unLoc pat') ty') }
925 zonk_pat _ pat = pprPanic "zonk_pat" (ppr pat)
927 ---------------------------
928 zonkConStuff :: ZonkEnv
929 -> HsConDetails (OutPat TcId) (HsRecFields id (OutPat TcId))
931 HsConDetails (OutPat Id) (HsRecFields id (OutPat Id)))
932 zonkConStuff env (PrefixCon pats)
933 = do { (env', pats') <- zonkPats env pats
934 ; return (env', PrefixCon pats') }
936 zonkConStuff env (InfixCon p1 p2)
937 = do { (env1, p1') <- zonkPat env p1
938 ; (env', p2') <- zonkPat env1 p2
939 ; return (env', InfixCon p1' p2') }
941 zonkConStuff env (RecCon (HsRecFields rpats dd))
942 = do { (env', pats') <- zonkPats env (map hsRecFieldArg rpats)
943 ; let rpats' = zipWith (\rp p' -> rp { hsRecFieldArg = p' }) rpats pats'
944 ; returnM (env', RecCon (HsRecFields rpats' dd)) }
945 -- Field selectors have declared types; hence no zonking
947 ---------------------------
948 zonkPats :: ZonkEnv -> [OutPat TcId] -> TcM (ZonkEnv, [OutPat Id])
949 zonkPats env [] = return (env, [])
950 zonkPats env (pat:pats) = do { (env1, pat') <- zonkPat env pat
951 ; (env', pats') <- zonkPats env1 pats
952 ; return (env', pat':pats') }
955 %************************************************************************
957 \subsection[BackSubst-Foreign]{Foreign exports}
959 %************************************************************************
963 zonkForeignExports :: ZonkEnv -> [LForeignDecl TcId] -> TcM [LForeignDecl Id]
964 zonkForeignExports env ls = mappM (wrapLocM (zonkForeignExport env)) ls
966 zonkForeignExport :: ZonkEnv -> ForeignDecl TcId -> TcM (ForeignDecl Id)
967 zonkForeignExport env (ForeignExport i _hs_ty spec) =
968 returnM (ForeignExport (fmap (zonkIdOcc env) i) undefined spec)
969 zonkForeignExport _ for_imp
970 = returnM for_imp -- Foreign imports don't need zonking
974 zonkRules :: ZonkEnv -> [LRuleDecl TcId] -> TcM [LRuleDecl Id]
975 zonkRules env rs = mappM (wrapLocM (zonkRule env)) rs
977 zonkRule :: ZonkEnv -> RuleDecl TcId -> TcM (RuleDecl Id)
978 zonkRule env (HsRule name act (vars{-::[RuleBndr TcId]-}) lhs fv_lhs rhs fv_rhs)
979 = do { (env_rhs, new_bndrs) <- mapAccumLM zonk_bndr env vars
981 ; unbound_tv_set <- newMutVar emptyVarSet
982 ; let env_lhs = setZonkType env_rhs (zonkTypeCollecting unbound_tv_set)
983 -- We need to gather the type variables mentioned on the LHS so we can
984 -- quantify over them. Example:
990 -- {-# RULES "myrule" foo C = 1 #-}
992 -- After type checking the LHS becomes (foo a (C a))
993 -- and we do not want to zap the unbound tyvar 'a' to (), because
994 -- that limits the applicability of the rule. Instead, we
995 -- want to quantify over it!
997 -- It's easiest to find the free tyvars here. Attempts to do so earlier
998 -- are tiresome, because (a) the data type is big and (b) finding the
999 -- free type vars of an expression is necessarily monadic operation.
1000 -- (consider /\a -> f @ b, where b is side-effected to a)
1002 ; new_lhs <- zonkLExpr env_lhs lhs
1003 ; new_rhs <- zonkLExpr env_rhs rhs
1005 ; unbound_tvs <- readMutVar unbound_tv_set
1006 ; let final_bndrs :: [RuleBndr Var]
1007 final_bndrs = map (RuleBndr . noLoc) (varSetElems unbound_tvs) ++ new_bndrs
1009 ; return (HsRule name act final_bndrs new_lhs fv_lhs new_rhs fv_rhs) }
1011 zonk_bndr env (RuleBndr (L loc v))
1012 = do { (env', v') <- zonk_it env v; return (env', RuleBndr (L loc v')) }
1013 zonk_bndr _ (RuleBndrSig {}) = panic "zonk_bndr RuleBndrSig"
1016 | isId v = do { v' <- zonkIdBndr env v; return (extendZonkEnv1 env v', v') }
1017 | isCoVar v = do { v' <- zonkEvBndr env v; return (extendZonkEnv1 env v', v') }
1018 | otherwise = ASSERT( isImmutableTyVar v) return (env, v)
1022 %************************************************************************
1024 Constraints and evidence
1026 %************************************************************************
1029 zonkEvTerm :: ZonkEnv -> EvTerm -> TcM EvTerm
1030 zonkEvTerm env (EvId v) = ASSERT2( isId v, ppr v )
1031 return (EvId (zonkIdOcc env v))
1032 zonkEvTerm env (EvCoercion co) = do { co' <- zonkTcTypeToType env co
1033 ; return (EvCoercion co') }
1034 zonkEvTerm env (EvCast v co) = ASSERT( isId v)
1035 do { co' <- zonkTcTypeToType env co
1036 ; return (EvCast (zonkIdOcc env v) co') }
1037 zonkEvTerm env (EvSuperClass d n) = return (EvSuperClass (zonkIdOcc env d) n)
1038 zonkEvTerm env (EvDFunApp df tys tms)
1039 = do { tys' <- zonkTcTypeToTypes env tys
1040 ; let tms' = map (zonkEvVarOcc env) tms
1041 ; return (EvDFunApp (zonkIdOcc env df) tys' tms') }
1043 zonkTcEvBinds :: ZonkEnv -> TcEvBinds -> TcM (ZonkEnv, TcEvBinds)
1044 zonkTcEvBinds env (TcEvBinds var) = do { (env', bs') <- zonkEvBindsVar env var
1045 ; return (env', EvBinds bs') }
1046 zonkTcEvBinds env (EvBinds bs) = do { (env', bs') <- zonkEvBinds env bs
1047 ; return (env', EvBinds bs') }
1049 zonkEvBindsVar :: ZonkEnv -> EvBindsVar -> TcM (ZonkEnv, Bag EvBind)
1050 zonkEvBindsVar env (EvBindsVar ref _) = do { bs <- readMutVar ref
1051 ; zonkEvBinds env (evBindMapBinds bs) }
1053 zonkEvBinds :: ZonkEnv -> Bag EvBind -> TcM (ZonkEnv, Bag EvBind)
1054 zonkEvBinds env binds
1055 = fixM (\ ~( _, new_binds) -> do
1056 { let env1 = extendZonkEnv env (collect_ev_bndrs new_binds)
1057 ; binds' <- mapBagM (zonkEvBind env1) binds
1058 ; return (env1, binds') })
1060 collect_ev_bndrs :: Bag EvBind -> [EvVar]
1061 collect_ev_bndrs = foldrBag add []
1062 add (EvBind var _) vars = var : vars
1064 zonkEvBind :: ZonkEnv -> EvBind -> TcM EvBind
1065 zonkEvBind env (EvBind var term)
1066 = do { var' <- zonkEvBndr env var
1067 ; term' <- zonkEvTerm env term
1068 ; return (EvBind var' term') }
1071 %************************************************************************
1073 \subsection[BackSubst-Foreign]{Foreign exports}
1075 %************************************************************************
1078 zonkTcTypeToType :: ZonkEnv -> TcType -> TcM Type
1079 zonkTcTypeToType (ZonkEnv zonk_ty _) ty = zonk_ty ty
1081 zonkTcTypeToTypes :: ZonkEnv -> [TcType] -> TcM [Type]
1082 zonkTcTypeToTypes env tys = mapM (zonkTcTypeToType env) tys
1084 zonkTypeCollecting :: TcRef TyVarSet -> TcType -> TcM Type
1085 -- This variant collects unbound type variables in a mutable variable
1086 zonkTypeCollecting unbound_tv_set
1087 = zonkType (mkZonkTcTyVar zonk_unbound_tyvar)
1089 zonk_unbound_tyvar tv
1090 = do { tv' <- zonkQuantifiedTyVar tv
1091 ; tv_set <- readMutVar unbound_tv_set
1092 ; writeMutVar unbound_tv_set (extendVarSet tv_set tv')
1093 ; return (mkTyVarTy tv') }
1095 zonkTypeZapping :: TcType -> TcM Type
1096 -- This variant is used for everything except the LHS of rules
1097 -- It zaps unbound type variables to (), or some other arbitrary type
1099 = zonkType (mkZonkTcTyVar zonk_unbound_tyvar) ty
1101 -- Zonk a mutable but unbound type variable to an arbitrary type
1102 -- We know it's unbound even though we don't carry an environment,
1103 -- because at the binding site for a type variable we bind the
1104 -- mutable tyvar to a fresh immutable one. So the mutable store
1105 -- plays the role of an environment. If we come across a mutable
1106 -- type variable that isn't so bound, it must be completely free.
1107 zonk_unbound_tyvar tv = do { let ty = anyTypeOfKind (tyVarKind tv)
1108 ; writeMetaTyVar tv ty