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] -> [LVectDecl TcId] -> [LTcSpecPrag] -> [LForeignDecl TcId]
280 zonkTopDecls ev_binds binds sig_ns rules vects imp_specs fords
281 = do { (env1, ev_binds') <- zonkEvBinds emptyZonkEnv ev_binds
283 -- Warn about missing signatures
284 -- Do this only when we we have a type to offer
285 ; warn_missing_sigs <- doptM Opt_WarnMissingSigs
286 ; let sig_warn | warn_missing_sigs = topSigWarn sig_ns
287 | otherwise = noSigWarn
289 ; (env2, binds') <- zonkRecMonoBinds env1 sig_warn binds
290 -- Top level is implicitly recursive
291 ; rules' <- zonkRules env2 rules
292 ; vects' <- zonkVects env2 vects
293 ; specs' <- zonkLTcSpecPrags env2 imp_specs
294 ; fords' <- zonkForeignExports env2 fords
295 ; return (zonkEnvIds env2, ev_binds', binds', fords', specs', rules', vects') }
297 ---------------------------------------------
298 zonkLocalBinds :: ZonkEnv -> HsLocalBinds TcId -> TcM (ZonkEnv, HsLocalBinds Id)
299 zonkLocalBinds env EmptyLocalBinds
300 = return (env, EmptyLocalBinds)
302 zonkLocalBinds _ (HsValBinds (ValBindsIn {}))
303 = panic "zonkLocalBinds" -- Not in typechecker output
305 zonkLocalBinds env (HsValBinds vb@(ValBindsOut binds sigs))
306 = do { warn_missing_sigs <- doptM Opt_WarnMissingLocalSigs
307 ; let sig_warn | not warn_missing_sigs = noSigWarn
308 | otherwise = localSigWarn sig_ns
309 sig_ns = getTypeSigNames vb
310 ; (env1, new_binds) <- go env sig_warn binds
311 ; return (env1, HsValBinds (ValBindsOut new_binds sigs)) }
315 go env sig_warn ((r,b):bs)
316 = do { (env1, b') <- zonkRecMonoBinds env sig_warn b
317 ; (env2, bs') <- go env1 sig_warn bs
318 ; return (env2, (r,b'):bs') }
320 zonkLocalBinds env (HsIPBinds (IPBinds binds dict_binds))
321 = mappM (wrapLocM zonk_ip_bind) binds `thenM` \ new_binds ->
323 env1 = extendZonkEnv env [ipNameName n | L _ (IPBind n _) <- new_binds]
325 zonkTcEvBinds env1 dict_binds `thenM` \ (env2, new_dict_binds) ->
326 returnM (env2, HsIPBinds (IPBinds new_binds new_dict_binds))
328 zonk_ip_bind (IPBind n e)
329 = mapIPNameTc (zonkIdBndr env) n `thenM` \ n' ->
330 zonkLExpr env e `thenM` \ e' ->
331 returnM (IPBind n' e')
333 ---------------------------------------------
334 zonkRecMonoBinds :: ZonkEnv -> SigWarn -> LHsBinds TcId -> TcM (ZonkEnv, LHsBinds Id)
335 zonkRecMonoBinds env sig_warn binds
336 = fixM (\ ~(_, new_binds) -> do
337 { let env1 = extendZonkEnv env (collectHsBindsBinders new_binds)
338 ; binds' <- zonkMonoBinds env1 sig_warn binds
339 ; return (env1, binds') })
341 ---------------------------------------------
342 type SigWarn = Bool -> [Id] -> TcM ()
343 -- Missing-signature warning
344 -- The Bool is True for an AbsBinds, False otherwise
347 noSigWarn _ _ = return ()
349 topSigWarn :: NameSet -> SigWarn
350 topSigWarn sig_ns _ ids = mapM_ (topSigWarnId sig_ns) ids
352 topSigWarnId :: NameSet -> Id -> TcM ()
353 -- The NameSet is the Ids that *lack* a signature
354 -- We have to do it this way round because there are
355 -- lots of top-level bindings that are generated by GHC
356 -- and that don't have signatures
357 topSigWarnId sig_ns id
358 | idName id `elemNameSet` sig_ns = warnMissingSig msg id
359 | otherwise = return ()
361 msg = ptext (sLit "Top-level binding with no type signature:")
363 localSigWarn :: NameSet -> SigWarn
364 localSigWarn sig_ns is_abs_bind ids
365 | not is_abs_bind = return ()
366 | otherwise = mapM_ (localSigWarnId sig_ns) ids
368 localSigWarnId :: NameSet -> Id -> TcM ()
369 -- NameSet are the Ids that *have* type signatures
370 localSigWarnId sig_ns id
371 | not (isSigmaTy (idType id)) = return ()
372 | idName id `elemNameSet` sig_ns = return ()
373 | otherwise = warnMissingSig msg id
375 msg = ptext (sLit "Polymophic local binding with no type signature:")
377 warnMissingSig :: SDoc -> Id -> TcM ()
378 warnMissingSig msg id
379 = do { env0 <- tcInitTidyEnv
380 ; let (env1, tidy_ty) = tidyOpenType env0 (idType id)
381 ; addWarnTcM (env1, mk_msg tidy_ty) }
383 mk_msg ty = sep [ msg, nest 2 $ pprHsVar (idName id) <+> dcolon <+> ppr ty ]
385 ---------------------------------------------
386 zonkMonoBinds :: ZonkEnv -> SigWarn -> LHsBinds TcId -> TcM (LHsBinds Id)
387 zonkMonoBinds env sig_warn binds = mapBagM (wrapLocM (zonk_bind env sig_warn)) binds
389 zonk_bind :: ZonkEnv -> SigWarn -> HsBind TcId -> TcM (HsBind Id)
390 zonk_bind env sig_warn bind@(PatBind { pat_lhs = pat, pat_rhs = grhss, pat_rhs_ty = ty})
391 = do { (_env, new_pat) <- zonkPat env pat -- Env already extended
392 ; sig_warn False (collectPatBinders new_pat)
393 ; new_grhss <- zonkGRHSs env grhss
394 ; new_ty <- zonkTcTypeToType env ty
395 ; return (bind { pat_lhs = new_pat, pat_rhs = new_grhss, pat_rhs_ty = new_ty }) }
397 zonk_bind env sig_warn (VarBind { var_id = var, var_rhs = expr, var_inline = inl })
398 = do { new_var <- zonkIdBndr env var
399 ; sig_warn False [new_var]
400 ; new_expr <- zonkLExpr env expr
401 ; return (VarBind { var_id = new_var, var_rhs = new_expr, var_inline = inl }) }
403 zonk_bind env sig_warn bind@(FunBind { fun_id = L loc var, fun_matches = ms
404 , fun_co_fn = co_fn })
405 = do { new_var <- zonkIdBndr env var
406 ; sig_warn False [new_var]
407 ; (env1, new_co_fn) <- zonkCoFn env co_fn
408 ; new_ms <- zonkMatchGroup env1 ms
409 ; return (bind { fun_id = L loc new_var, fun_matches = new_ms
410 , fun_co_fn = new_co_fn }) }
412 zonk_bind env sig_warn (AbsBinds { abs_tvs = tyvars, abs_ev_vars = evs
413 , abs_ev_binds = ev_binds
414 , abs_exports = exports
415 , abs_binds = val_binds })
416 = ASSERT( all isImmutableTyVar tyvars )
417 do { (env1, new_evs) <- zonkEvBndrsX env evs
418 ; (env2, new_ev_binds) <- zonkTcEvBinds env1 ev_binds
419 ; (new_val_bind, new_exports) <- fixM $ \ ~(new_val_binds, _) ->
420 do { let env3 = extendZonkEnv env2 (collectHsBindsBinders new_val_binds)
421 ; new_val_binds <- zonkMonoBinds env3 noSigWarn val_binds
422 ; new_exports <- mapM (zonkExport env3) exports
423 ; return (new_val_binds, new_exports) }
424 ; sig_warn True [b | (_,b,_,_) <- new_exports]
425 ; return (AbsBinds { abs_tvs = tyvars, abs_ev_vars = new_evs, abs_ev_binds = new_ev_binds
426 , abs_exports = new_exports, abs_binds = new_val_bind }) }
428 zonkExport env (tyvars, global, local, prags)
429 -- The tyvars are already zonked
430 = zonkIdBndr env global `thenM` \ new_global ->
431 zonkSpecPrags env prags `thenM` \ new_prags ->
432 returnM (tyvars, new_global, zonkIdOcc env local, new_prags)
434 zonkSpecPrags :: ZonkEnv -> TcSpecPrags -> TcM TcSpecPrags
435 zonkSpecPrags _ IsDefaultMethod = return IsDefaultMethod
436 zonkSpecPrags env (SpecPrags ps) = do { ps' <- zonkLTcSpecPrags env ps
437 ; return (SpecPrags ps') }
439 zonkLTcSpecPrags :: ZonkEnv -> [LTcSpecPrag] -> TcM [LTcSpecPrag]
440 zonkLTcSpecPrags env ps
443 zonk_prag (L loc (SpecPrag id co_fn inl))
444 = do { (_, co_fn') <- zonkCoFn env co_fn
445 ; return (L loc (SpecPrag (zonkIdOcc env id) co_fn' inl)) }
448 %************************************************************************
450 \subsection[BackSubst-Match-GRHSs]{Match and GRHSs}
452 %************************************************************************
455 zonkMatchGroup :: ZonkEnv -> MatchGroup TcId-> TcM (MatchGroup Id)
456 zonkMatchGroup env (MatchGroup ms ty)
457 = do { ms' <- mapM (zonkMatch env) ms
458 ; ty' <- zonkTcTypeToType env ty
459 ; return (MatchGroup ms' ty') }
461 zonkMatch :: ZonkEnv -> LMatch TcId-> TcM (LMatch Id)
462 zonkMatch env (L loc (Match pats _ grhss))
463 = do { (env1, new_pats) <- zonkPats env pats
464 ; new_grhss <- zonkGRHSs env1 grhss
465 ; return (L loc (Match new_pats Nothing new_grhss)) }
467 -------------------------------------------------------------------------
468 zonkGRHSs :: ZonkEnv -> GRHSs TcId -> TcM (GRHSs Id)
470 zonkGRHSs env (GRHSs grhss binds)
471 = zonkLocalBinds env binds `thenM` \ (new_env, new_binds) ->
473 zonk_grhs (GRHS guarded rhs)
474 = zonkStmts new_env guarded `thenM` \ (env2, new_guarded) ->
475 zonkLExpr env2 rhs `thenM` \ new_rhs ->
476 returnM (GRHS new_guarded new_rhs)
478 mappM (wrapLocM zonk_grhs) grhss `thenM` \ new_grhss ->
479 returnM (GRHSs new_grhss new_binds)
482 %************************************************************************
484 \subsection[BackSubst-HsExpr]{Running a zonkitution over a TypeCheckedExpr}
486 %************************************************************************
489 zonkLExprs :: ZonkEnv -> [LHsExpr TcId] -> TcM [LHsExpr Id]
490 zonkLExpr :: ZonkEnv -> LHsExpr TcId -> TcM (LHsExpr Id)
491 zonkExpr :: ZonkEnv -> HsExpr TcId -> TcM (HsExpr Id)
493 zonkLExprs env exprs = mappM (zonkLExpr env) exprs
494 zonkLExpr env expr = wrapLocM (zonkExpr env) expr
496 zonkExpr env (HsVar id)
497 = returnM (HsVar (zonkIdOcc env id))
499 zonkExpr env (HsIPVar id)
500 = returnM (HsIPVar (mapIPName (zonkIdOcc env) id))
502 zonkExpr env (HsLit (HsRat f ty))
503 = zonkTcTypeToType env ty `thenM` \ new_ty ->
504 returnM (HsLit (HsRat f new_ty))
506 zonkExpr _ (HsLit lit)
507 = returnM (HsLit lit)
509 zonkExpr env (HsOverLit lit)
510 = do { lit' <- zonkOverLit env lit
511 ; return (HsOverLit lit') }
513 zonkExpr env (HsLam matches)
514 = zonkMatchGroup env matches `thenM` \ new_matches ->
515 returnM (HsLam new_matches)
517 zonkExpr env (HsApp e1 e2)
518 = zonkLExpr env e1 `thenM` \ new_e1 ->
519 zonkLExpr env e2 `thenM` \ new_e2 ->
520 returnM (HsApp new_e1 new_e2)
522 zonkExpr env (HsBracketOut body bs)
523 = mappM zonk_b bs `thenM` \ bs' ->
524 returnM (HsBracketOut body bs')
526 zonk_b (n,e) = zonkLExpr env e `thenM` \ e' ->
529 zonkExpr _ (HsSpliceE s) = WARN( True, ppr s ) -- Should not happen
530 returnM (HsSpliceE s)
532 zonkExpr env (OpApp e1 op fixity e2)
533 = zonkLExpr env e1 `thenM` \ new_e1 ->
534 zonkLExpr env op `thenM` \ new_op ->
535 zonkLExpr env e2 `thenM` \ new_e2 ->
536 returnM (OpApp new_e1 new_op fixity new_e2)
538 zonkExpr env (NegApp expr op)
539 = zonkLExpr env expr `thenM` \ new_expr ->
540 zonkExpr env op `thenM` \ new_op ->
541 returnM (NegApp new_expr new_op)
543 zonkExpr env (HsPar e)
544 = zonkLExpr env e `thenM` \new_e ->
545 returnM (HsPar new_e)
547 zonkExpr env (SectionL expr op)
548 = zonkLExpr env expr `thenM` \ new_expr ->
549 zonkLExpr env op `thenM` \ new_op ->
550 returnM (SectionL new_expr new_op)
552 zonkExpr env (SectionR op expr)
553 = zonkLExpr env op `thenM` \ new_op ->
554 zonkLExpr env expr `thenM` \ new_expr ->
555 returnM (SectionR new_op new_expr)
557 zonkExpr env (ExplicitTuple tup_args boxed)
558 = do { new_tup_args <- mapM zonk_tup_arg tup_args
559 ; return (ExplicitTuple new_tup_args boxed) }
561 zonk_tup_arg (Present e) = do { e' <- zonkLExpr env e; return (Present e') }
562 zonk_tup_arg (Missing t) = do { t' <- zonkTcTypeToType env t; return (Missing t') }
564 zonkExpr env (HsCase expr ms)
565 = zonkLExpr env expr `thenM` \ new_expr ->
566 zonkMatchGroup env ms `thenM` \ new_ms ->
567 returnM (HsCase new_expr new_ms)
569 zonkExpr env (HsIf e0 e1 e2 e3)
570 = do { new_e0 <- fmapMaybeM (zonkExpr env) e0
571 ; new_e1 <- zonkLExpr env e1
572 ; new_e2 <- zonkLExpr env e2
573 ; new_e3 <- zonkLExpr env e3
574 ; returnM (HsIf new_e0 new_e1 new_e2 new_e3) }
576 zonkExpr env (HsLet binds expr)
577 = zonkLocalBinds env binds `thenM` \ (new_env, new_binds) ->
578 zonkLExpr new_env expr `thenM` \ new_expr ->
579 returnM (HsLet new_binds new_expr)
581 zonkExpr env (HsDo do_or_lc stmts ty)
582 = zonkStmts env stmts `thenM` \ (_, new_stmts) ->
583 zonkTcTypeToType env ty `thenM` \ new_ty ->
584 returnM (HsDo do_or_lc new_stmts 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 zonkOverLit :: ZonkEnv -> HsOverLit TcId -> TcM (HsOverLit Id)
693 zonkOverLit env lit@(OverLit { ol_witness = e, ol_type = ty })
694 = do { ty' <- zonkTcTypeToType env ty
695 ; e' <- zonkExpr env e
696 ; return (lit { ol_witness = e', ol_type = ty' }) }
698 -------------------------------------------------------------------------
699 zonkArithSeq :: ZonkEnv -> ArithSeqInfo TcId -> TcM (ArithSeqInfo Id)
701 zonkArithSeq env (From e)
702 = zonkLExpr env e `thenM` \ new_e ->
705 zonkArithSeq env (FromThen e1 e2)
706 = zonkLExpr env e1 `thenM` \ new_e1 ->
707 zonkLExpr env e2 `thenM` \ new_e2 ->
708 returnM (FromThen new_e1 new_e2)
710 zonkArithSeq env (FromTo e1 e2)
711 = zonkLExpr env e1 `thenM` \ new_e1 ->
712 zonkLExpr env e2 `thenM` \ new_e2 ->
713 returnM (FromTo new_e1 new_e2)
715 zonkArithSeq env (FromThenTo e1 e2 e3)
716 = zonkLExpr env e1 `thenM` \ new_e1 ->
717 zonkLExpr env e2 `thenM` \ new_e2 ->
718 zonkLExpr env e3 `thenM` \ new_e3 ->
719 returnM (FromThenTo new_e1 new_e2 new_e3)
722 -------------------------------------------------------------------------
723 zonkStmts :: ZonkEnv -> [LStmt TcId] -> TcM (ZonkEnv, [LStmt Id])
724 zonkStmts env [] = return (env, [])
725 zonkStmts env (s:ss) = do { (env1, s') <- wrapLocSndM (zonkStmt env) s
726 ; (env2, ss') <- zonkStmts env1 ss
727 ; return (env2, s' : ss') }
729 zonkStmt :: ZonkEnv -> Stmt TcId -> TcM (ZonkEnv, Stmt Id)
730 zonkStmt env (ParStmt stmts_w_bndrs mzip_op bind_op return_op)
731 = mappM zonk_branch stmts_w_bndrs `thenM` \ new_stmts_w_bndrs ->
733 new_binders = concat (map snd new_stmts_w_bndrs)
734 env1 = extendZonkEnv env new_binders
736 zonkExpr env1 mzip_op `thenM` \ new_mzip ->
737 zonkExpr env1 bind_op `thenM` \ new_bind ->
738 zonkExpr env1 return_op `thenM` \ new_return ->
739 return (env1, ParStmt new_stmts_w_bndrs new_mzip new_bind new_return)
741 zonk_branch (stmts, bndrs) = zonkStmts env stmts `thenM` \ (env1, new_stmts) ->
742 returnM (new_stmts, zonkIdOccs env1 bndrs)
744 zonkStmt env (RecStmt { recS_stmts = segStmts, recS_later_ids = lvs, recS_rec_ids = rvs
745 , recS_ret_fn = ret_id, recS_mfix_fn = mfix_id, recS_bind_fn = bind_id
746 , recS_rec_rets = rets, recS_ret_ty = ret_ty })
747 = do { new_rvs <- zonkIdBndrs env rvs
748 ; new_lvs <- zonkIdBndrs env lvs
749 ; new_ret_ty <- zonkTcTypeToType env ret_ty
750 ; new_ret_id <- zonkExpr env ret_id
751 ; new_mfix_id <- zonkExpr env mfix_id
752 ; new_bind_id <- zonkExpr env bind_id
753 ; let env1 = extendZonkEnv env new_rvs
754 ; (env2, new_segStmts) <- zonkStmts env1 segStmts
755 -- Zonk the ret-expressions in an envt that
756 -- has the polymorphic bindings in the envt
757 ; new_rets <- mapM (zonkExpr env2) rets
758 ; return (extendZonkEnv env new_lvs, -- Only the lvs are needed
759 RecStmt { recS_stmts = new_segStmts, recS_later_ids = new_lvs
760 , recS_rec_ids = new_rvs, recS_ret_fn = new_ret_id
761 , recS_mfix_fn = new_mfix_id, recS_bind_fn = new_bind_id
762 , recS_rec_rets = new_rets, recS_ret_ty = new_ret_ty }) }
764 zonkStmt env (ExprStmt expr then_op guard_op ty)
765 = zonkLExpr env expr `thenM` \ new_expr ->
766 zonkExpr env then_op `thenM` \ new_then ->
767 zonkExpr env guard_op `thenM` \ new_guard ->
768 zonkTcTypeToType env ty `thenM` \ new_ty ->
769 returnM (env, ExprStmt new_expr new_then new_guard new_ty)
771 zonkStmt env (LastStmt expr ret_op)
772 = zonkLExpr env expr `thenM` \ new_expr ->
773 zonkExpr env ret_op `thenM` \ new_ret ->
774 returnM (env, LastStmt new_expr new_ret)
776 zonkStmt env (TransStmt { trS_stmts = stmts, trS_bndrs = binderMap
777 , trS_by = by, trS_form = form, trS_using = using
778 , trS_ret = return_op, trS_bind = bind_op, trS_fmap = liftM_op })
779 = do { (env', stmts') <- zonkStmts env stmts
780 ; binderMap' <- mappM (zonkBinderMapEntry env') binderMap
781 ; by' <- fmapMaybeM (zonkLExpr env') by
782 ; using' <- zonkLExpr env using
783 ; return_op' <- zonkExpr env' return_op
784 ; bind_op' <- zonkExpr env' bind_op
785 ; liftM_op' <- zonkExpr env' liftM_op
786 ; let env'' = extendZonkEnv env' (map snd binderMap')
787 ; return (env'', TransStmt { trS_stmts = stmts', trS_bndrs = binderMap'
788 , trS_by = by', trS_form = form, trS_using = using'
789 , trS_ret = return_op', trS_bind = bind_op', trS_fmap = liftM_op' }) }
791 zonkBinderMapEntry env (oldBinder, newBinder) = do
792 let oldBinder' = zonkIdOcc env oldBinder
793 newBinder' <- zonkIdBndr env newBinder
794 return (oldBinder', newBinder')
796 zonkStmt env (LetStmt binds)
797 = zonkLocalBinds env binds `thenM` \ (env1, new_binds) ->
798 returnM (env1, LetStmt new_binds)
800 zonkStmt env (BindStmt pat expr bind_op fail_op)
801 = do { new_expr <- zonkLExpr env expr
802 ; (env1, new_pat) <- zonkPat env pat
803 ; new_bind <- zonkExpr env bind_op
804 ; new_fail <- zonkExpr env fail_op
805 ; return (env1, BindStmt new_pat new_expr new_bind new_fail) }
807 -------------------------------------------------------------------------
808 zonkRecFields :: ZonkEnv -> HsRecordBinds TcId -> TcM (HsRecordBinds TcId)
809 zonkRecFields env (HsRecFields flds dd)
810 = do { flds' <- mappM zonk_rbind flds
811 ; return (HsRecFields flds' dd) }
814 = do { new_id <- wrapLocM (zonkIdBndr env) (hsRecFieldId fld)
815 ; new_expr <- zonkLExpr env (hsRecFieldArg fld)
816 ; return (fld { hsRecFieldId = new_id, hsRecFieldArg = new_expr }) }
818 -------------------------------------------------------------------------
819 mapIPNameTc :: (a -> TcM b) -> IPName a -> TcM (IPName b)
820 mapIPNameTc f (IPName n) = f n `thenM` \ r -> returnM (IPName r)
824 %************************************************************************
826 \subsection[BackSubst-Pats]{Patterns}
828 %************************************************************************
831 zonkPat :: ZonkEnv -> OutPat TcId -> TcM (ZonkEnv, OutPat Id)
832 -- Extend the environment as we go, because it's possible for one
833 -- pattern to bind something that is used in another (inside or
835 zonkPat env pat = wrapLocSndM (zonk_pat env) pat
837 zonk_pat :: ZonkEnv -> Pat TcId -> TcM (ZonkEnv, Pat Id)
838 zonk_pat env (ParPat p)
839 = do { (env', p') <- zonkPat env p
840 ; return (env', ParPat p') }
842 zonk_pat env (WildPat ty)
843 = do { ty' <- zonkTcTypeToType env ty
844 ; return (env, WildPat ty') }
846 zonk_pat env (VarPat v)
847 = do { v' <- zonkIdBndr env v
848 ; return (extendZonkEnv1 env v', VarPat v') }
850 zonk_pat env (LazyPat pat)
851 = do { (env', pat') <- zonkPat env pat
852 ; return (env', LazyPat pat') }
854 zonk_pat env (BangPat pat)
855 = do { (env', pat') <- zonkPat env pat
856 ; return (env', BangPat pat') }
858 zonk_pat env (AsPat (L loc v) pat)
859 = do { v' <- zonkIdBndr env v
860 ; (env', pat') <- zonkPat (extendZonkEnv1 env v') pat
861 ; return (env', AsPat (L loc v') pat') }
863 zonk_pat env (ViewPat expr pat ty)
864 = do { expr' <- zonkLExpr env expr
865 ; (env', pat') <- zonkPat env pat
866 ; ty' <- zonkTcTypeToType env ty
867 ; return (env', ViewPat expr' pat' ty') }
869 zonk_pat env (ListPat pats ty)
870 = do { ty' <- zonkTcTypeToType env ty
871 ; (env', pats') <- zonkPats env pats
872 ; return (env', ListPat pats' ty') }
874 zonk_pat env (PArrPat pats ty)
875 = do { ty' <- zonkTcTypeToType env ty
876 ; (env', pats') <- zonkPats env pats
877 ; return (env', PArrPat pats' ty') }
879 zonk_pat env (TuplePat pats boxed ty)
880 = do { ty' <- zonkTcTypeToType env ty
881 ; (env', pats') <- zonkPats env pats
882 ; return (env', TuplePat pats' boxed ty') }
884 zonk_pat env p@(ConPatOut { pat_ty = ty, pat_dicts = evs, pat_binds = binds, pat_args = args })
885 = ASSERT( all isImmutableTyVar (pat_tvs p) )
886 do { new_ty <- zonkTcTypeToType env ty
887 ; (env1, new_evs) <- zonkEvBndrsX env evs
888 ; (env2, new_binds) <- zonkTcEvBinds env1 binds
889 ; (env', new_args) <- zonkConStuff env2 args
890 ; returnM (env', p { pat_ty = new_ty, pat_dicts = new_evs,
891 pat_binds = new_binds, pat_args = new_args }) }
893 zonk_pat env (LitPat lit) = return (env, LitPat lit)
895 zonk_pat env (SigPatOut pat ty)
896 = do { ty' <- zonkTcTypeToType env ty
897 ; (env', pat') <- zonkPat env pat
898 ; return (env', SigPatOut pat' ty') }
900 zonk_pat env (NPat lit mb_neg eq_expr)
901 = do { lit' <- zonkOverLit env lit
902 ; mb_neg' <- fmapMaybeM (zonkExpr env) mb_neg
903 ; eq_expr' <- zonkExpr env eq_expr
904 ; return (env, NPat lit' mb_neg' eq_expr') }
906 zonk_pat env (NPlusKPat (L loc n) lit e1 e2)
907 = do { n' <- zonkIdBndr env n
908 ; lit' <- zonkOverLit env lit
909 ; e1' <- zonkExpr env e1
910 ; e2' <- zonkExpr env e2
911 ; return (extendZonkEnv1 env n', NPlusKPat (L loc n') lit' e1' e2') }
913 zonk_pat env (CoPat co_fn pat ty)
914 = do { (env', co_fn') <- zonkCoFn env co_fn
915 ; (env'', pat') <- zonkPat env' (noLoc pat)
916 ; ty' <- zonkTcTypeToType env'' ty
917 ; return (env'', CoPat co_fn' (unLoc pat') ty') }
919 zonk_pat _ pat = pprPanic "zonk_pat" (ppr pat)
921 ---------------------------
922 zonkConStuff :: ZonkEnv
923 -> HsConDetails (OutPat TcId) (HsRecFields id (OutPat TcId))
925 HsConDetails (OutPat Id) (HsRecFields id (OutPat Id)))
926 zonkConStuff env (PrefixCon pats)
927 = do { (env', pats') <- zonkPats env pats
928 ; return (env', PrefixCon pats') }
930 zonkConStuff env (InfixCon p1 p2)
931 = do { (env1, p1') <- zonkPat env p1
932 ; (env', p2') <- zonkPat env1 p2
933 ; return (env', InfixCon p1' p2') }
935 zonkConStuff env (RecCon (HsRecFields rpats dd))
936 = do { (env', pats') <- zonkPats env (map hsRecFieldArg rpats)
937 ; let rpats' = zipWith (\rp p' -> rp { hsRecFieldArg = p' }) rpats pats'
938 ; returnM (env', RecCon (HsRecFields rpats' dd)) }
939 -- Field selectors have declared types; hence no zonking
941 ---------------------------
942 zonkPats :: ZonkEnv -> [OutPat TcId] -> TcM (ZonkEnv, [OutPat Id])
943 zonkPats env [] = return (env, [])
944 zonkPats env (pat:pats) = do { (env1, pat') <- zonkPat env pat
945 ; (env', pats') <- zonkPats env1 pats
946 ; return (env', pat':pats') }
949 %************************************************************************
951 \subsection[BackSubst-Foreign]{Foreign exports}
953 %************************************************************************
957 zonkForeignExports :: ZonkEnv -> [LForeignDecl TcId] -> TcM [LForeignDecl Id]
958 zonkForeignExports env ls = mappM (wrapLocM (zonkForeignExport env)) ls
960 zonkForeignExport :: ZonkEnv -> ForeignDecl TcId -> TcM (ForeignDecl Id)
961 zonkForeignExport env (ForeignExport i _hs_ty spec) =
962 returnM (ForeignExport (fmap (zonkIdOcc env) i) undefined spec)
963 zonkForeignExport _ for_imp
964 = returnM for_imp -- Foreign imports don't need zonking
968 zonkRules :: ZonkEnv -> [LRuleDecl TcId] -> TcM [LRuleDecl Id]
969 zonkRules env rs = mappM (wrapLocM (zonkRule env)) rs
971 zonkRule :: ZonkEnv -> RuleDecl TcId -> TcM (RuleDecl Id)
972 zonkRule env (HsRule name act (vars{-::[RuleBndr TcId]-}) lhs fv_lhs rhs fv_rhs)
973 = do { (env_rhs, new_bndrs) <- mapAccumLM zonk_bndr env vars
975 ; unbound_tv_set <- newMutVar emptyVarSet
976 ; let env_lhs = setZonkType env_rhs (zonkTypeCollecting unbound_tv_set)
977 -- We need to gather the type variables mentioned on the LHS so we can
978 -- quantify over them. Example:
984 -- {-# RULES "myrule" foo C = 1 #-}
986 -- After type checking the LHS becomes (foo a (C a))
987 -- and we do not want to zap the unbound tyvar 'a' to (), because
988 -- that limits the applicability of the rule. Instead, we
989 -- want to quantify over it!
991 -- It's easiest to find the free tyvars here. Attempts to do so earlier
992 -- are tiresome, because (a) the data type is big and (b) finding the
993 -- free type vars of an expression is necessarily monadic operation.
994 -- (consider /\a -> f @ b, where b is side-effected to a)
996 ; new_lhs <- zonkLExpr env_lhs lhs
997 ; new_rhs <- zonkLExpr env_rhs rhs
999 ; unbound_tvs <- readMutVar unbound_tv_set
1000 ; let final_bndrs :: [RuleBndr Var]
1001 final_bndrs = map (RuleBndr . noLoc) (varSetElems unbound_tvs) ++ new_bndrs
1003 ; return (HsRule name act final_bndrs new_lhs fv_lhs new_rhs fv_rhs) }
1005 zonk_bndr env (RuleBndr (L loc v))
1006 = do { (env', v') <- zonk_it env v; return (env', RuleBndr (L loc v')) }
1007 zonk_bndr _ (RuleBndrSig {}) = panic "zonk_bndr RuleBndrSig"
1010 | isId v = do { v' <- zonkIdBndr env v; return (extendZonkEnv1 env v', v') }
1011 | isCoVar v = do { v' <- zonkEvBndr env v; return (extendZonkEnv1 env v', v') }
1012 | otherwise = ASSERT( isImmutableTyVar v) return (env, v)
1016 zonkVects :: ZonkEnv -> [LVectDecl TcId] -> TcM [LVectDecl Id]
1017 zonkVects env = mappM (wrapLocM (zonkVect env))
1019 zonkVect :: ZonkEnv -> VectDecl TcId -> TcM (VectDecl Id)
1020 zonkVect env (HsVect v Nothing)
1021 = do { v' <- wrapLocM (zonkIdBndr env) v
1022 ; return $ HsVect v' Nothing
1024 zonkVect env (HsVect v (Just e))
1025 = do { v' <- wrapLocM (zonkIdBndr env) v
1026 ; e' <- zonkLExpr env e
1027 ; return $ HsVect v' (Just e')
1031 %************************************************************************
1033 Constraints and evidence
1035 %************************************************************************
1038 zonkEvTerm :: ZonkEnv -> EvTerm -> TcM EvTerm
1039 zonkEvTerm env (EvId v) = ASSERT2( isId v, ppr v )
1040 return (EvId (zonkIdOcc env v))
1041 zonkEvTerm env (EvCoercion co) = do { co' <- zonkTcTypeToType env co
1042 ; return (EvCoercion co') }
1043 zonkEvTerm env (EvCast v co) = ASSERT( isId v)
1044 do { co' <- zonkTcTypeToType env co
1045 ; return (EvCast (zonkIdOcc env v) co') }
1046 zonkEvTerm env (EvSuperClass d n) = return (EvSuperClass (zonkIdOcc env d) n)
1047 zonkEvTerm env (EvDFunApp df tys tms)
1048 = do { tys' <- zonkTcTypeToTypes env tys
1049 ; let tms' = map (zonkEvVarOcc env) tms
1050 ; return (EvDFunApp (zonkIdOcc env df) tys' tms') }
1052 zonkTcEvBinds :: ZonkEnv -> TcEvBinds -> TcM (ZonkEnv, TcEvBinds)
1053 zonkTcEvBinds env (TcEvBinds var) = do { (env', bs') <- zonkEvBindsVar env var
1054 ; return (env', EvBinds bs') }
1055 zonkTcEvBinds env (EvBinds bs) = do { (env', bs') <- zonkEvBinds env bs
1056 ; return (env', EvBinds bs') }
1058 zonkEvBindsVar :: ZonkEnv -> EvBindsVar -> TcM (ZonkEnv, Bag EvBind)
1059 zonkEvBindsVar env (EvBindsVar ref _) = do { bs <- readMutVar ref
1060 ; zonkEvBinds env (evBindMapBinds bs) }
1062 zonkEvBinds :: ZonkEnv -> Bag EvBind -> TcM (ZonkEnv, Bag EvBind)
1063 zonkEvBinds env binds
1064 = fixM (\ ~( _, new_binds) -> do
1065 { let env1 = extendZonkEnv env (collect_ev_bndrs new_binds)
1066 ; binds' <- mapBagM (zonkEvBind env1) binds
1067 ; return (env1, binds') })
1069 collect_ev_bndrs :: Bag EvBind -> [EvVar]
1070 collect_ev_bndrs = foldrBag add []
1071 add (EvBind var _) vars = var : vars
1073 zonkEvBind :: ZonkEnv -> EvBind -> TcM EvBind
1074 zonkEvBind env (EvBind var term)
1075 = do { var' <- zonkEvBndr env var
1076 ; term' <- zonkEvTerm env term
1077 ; return (EvBind var' term') }
1080 %************************************************************************
1084 %************************************************************************
1087 zonkTcTypeToType :: ZonkEnv -> TcType -> TcM Type
1088 zonkTcTypeToType (ZonkEnv zonk_ty _) ty = zonk_ty ty
1090 zonkTcTypeToTypes :: ZonkEnv -> [TcType] -> TcM [Type]
1091 zonkTcTypeToTypes env tys = mapM (zonkTcTypeToType env) tys
1093 zonkTypeCollecting :: TcRef TyVarSet -> TcType -> TcM Type
1094 -- This variant collects unbound type variables in a mutable variable
1095 zonkTypeCollecting unbound_tv_set
1096 = zonkType (mkZonkTcTyVar zonk_unbound_tyvar)
1098 zonk_unbound_tyvar tv
1099 = do { tv' <- zonkQuantifiedTyVar tv
1100 ; tv_set <- readMutVar unbound_tv_set
1101 ; writeMutVar unbound_tv_set (extendVarSet tv_set tv')
1102 ; return (mkTyVarTy tv') }
1104 zonkTypeZapping :: TcType -> TcM Type
1105 -- This variant is used for everything except the LHS of rules
1106 -- It zaps unbound type variables to (), or some other arbitrary type
1108 = zonkType (mkZonkTcTyVar zonk_unbound_tyvar) ty
1110 -- Zonk a mutable but unbound type variable to an arbitrary type
1111 -- We know it's unbound even though we don't carry an environment,
1112 -- because at the binding site for a type variable we bind the
1113 -- mutable tyvar to a fresh immutable one. So the mutable store
1114 -- plays the role of an environment. If we come across a mutable
1115 -- type variable that isn't so bound, it must be completely free.
1116 zonk_unbound_tyvar tv = do { let ty = anyTypeOfKind (tyVarKind tv)
1117 ; writeMetaTyVar tv ty