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 body return_op ty)
582 = zonkStmts env stmts `thenM` \ (new_env, new_stmts) ->
583 zonkLExpr new_env body `thenM` \ new_body ->
584 zonkExpr new_env return_op `thenM` \ new_return ->
585 zonkTcTypeToType env ty `thenM` \ new_ty ->
586 returnM (HsDo do_or_lc new_stmts new_body new_return new_ty)
588 zonkExpr env (ExplicitList ty exprs)
589 = zonkTcTypeToType env ty `thenM` \ new_ty ->
590 zonkLExprs env exprs `thenM` \ new_exprs ->
591 returnM (ExplicitList new_ty new_exprs)
593 zonkExpr env (ExplicitPArr ty exprs)
594 = zonkTcTypeToType env ty `thenM` \ new_ty ->
595 zonkLExprs env exprs `thenM` \ new_exprs ->
596 returnM (ExplicitPArr new_ty new_exprs)
598 zonkExpr env (RecordCon data_con con_expr rbinds)
599 = do { new_con_expr <- zonkExpr env con_expr
600 ; new_rbinds <- zonkRecFields env rbinds
601 ; return (RecordCon data_con new_con_expr new_rbinds) }
603 zonkExpr env (RecordUpd expr rbinds cons in_tys out_tys)
604 = do { new_expr <- zonkLExpr env expr
605 ; new_in_tys <- mapM (zonkTcTypeToType env) in_tys
606 ; new_out_tys <- mapM (zonkTcTypeToType env) out_tys
607 ; new_rbinds <- zonkRecFields env rbinds
608 ; return (RecordUpd new_expr new_rbinds cons new_in_tys new_out_tys) }
610 zonkExpr env (ExprWithTySigOut e ty)
611 = do { e' <- zonkLExpr env e
612 ; return (ExprWithTySigOut e' ty) }
614 zonkExpr _ (ExprWithTySig _ _) = panic "zonkExpr env:ExprWithTySig"
616 zonkExpr env (ArithSeq expr info)
617 = zonkExpr env expr `thenM` \ new_expr ->
618 zonkArithSeq env info `thenM` \ new_info ->
619 returnM (ArithSeq new_expr new_info)
621 zonkExpr env (PArrSeq expr info)
622 = zonkExpr env expr `thenM` \ new_expr ->
623 zonkArithSeq env info `thenM` \ new_info ->
624 returnM (PArrSeq new_expr new_info)
626 zonkExpr env (HsSCC lbl expr)
627 = zonkLExpr env expr `thenM` \ new_expr ->
628 returnM (HsSCC lbl new_expr)
630 zonkExpr env (HsTickPragma info expr)
631 = zonkLExpr env expr `thenM` \ new_expr ->
632 returnM (HsTickPragma info new_expr)
634 -- hdaume: core annotations
635 zonkExpr env (HsCoreAnn lbl expr)
636 = zonkLExpr env expr `thenM` \ new_expr ->
637 returnM (HsCoreAnn lbl new_expr)
639 -- arrow notation extensions
640 zonkExpr env (HsProc pat body)
641 = do { (env1, new_pat) <- zonkPat env pat
642 ; new_body <- zonkCmdTop env1 body
643 ; return (HsProc new_pat new_body) }
645 zonkExpr env (HsArrApp e1 e2 ty ho rl)
646 = zonkLExpr env e1 `thenM` \ new_e1 ->
647 zonkLExpr env e2 `thenM` \ new_e2 ->
648 zonkTcTypeToType env ty `thenM` \ new_ty ->
649 returnM (HsArrApp new_e1 new_e2 new_ty ho rl)
651 zonkExpr env (HsArrForm op fixity args)
652 = zonkLExpr env op `thenM` \ new_op ->
653 mappM (zonkCmdTop env) args `thenM` \ new_args ->
654 returnM (HsArrForm new_op fixity new_args)
656 zonkExpr env (HsWrap co_fn expr)
657 = zonkCoFn env co_fn `thenM` \ (env1, new_co_fn) ->
658 zonkExpr env1 expr `thenM` \ new_expr ->
659 return (HsWrap new_co_fn new_expr)
661 zonkExpr _ expr = pprPanic "zonkExpr" (ppr expr)
663 zonkCmdTop :: ZonkEnv -> LHsCmdTop TcId -> TcM (LHsCmdTop Id)
664 zonkCmdTop env cmd = wrapLocM (zonk_cmd_top env) cmd
666 zonk_cmd_top :: ZonkEnv -> HsCmdTop TcId -> TcM (HsCmdTop Id)
667 zonk_cmd_top env (HsCmdTop cmd stack_tys ty ids)
668 = zonkLExpr env cmd `thenM` \ new_cmd ->
669 zonkTcTypeToTypes env stack_tys `thenM` \ new_stack_tys ->
670 zonkTcTypeToType env ty `thenM` \ new_ty ->
671 mapSndM (zonkExpr env) ids `thenM` \ new_ids ->
672 returnM (HsCmdTop new_cmd new_stack_tys new_ty new_ids)
674 -------------------------------------------------------------------------
675 zonkCoFn :: ZonkEnv -> HsWrapper -> TcM (ZonkEnv, HsWrapper)
676 zonkCoFn env WpHole = return (env, WpHole)
677 zonkCoFn env (WpCompose c1 c2) = do { (env1, c1') <- zonkCoFn env c1
678 ; (env2, c2') <- zonkCoFn env1 c2
679 ; return (env2, WpCompose c1' c2') }
680 zonkCoFn env (WpCast co) = do { co' <- zonkTcTypeToType env co
681 ; return (env, WpCast co') }
682 zonkCoFn env (WpEvLam ev) = do { (env', ev') <- zonkEvBndrX env ev
683 ; return (env', WpEvLam ev') }
684 zonkCoFn env (WpEvApp arg) = do { arg' <- zonkEvTerm env arg
685 ; return (env, WpEvApp arg') }
686 zonkCoFn env (WpTyLam tv) = ASSERT( isImmutableTyVar tv )
687 return (env, WpTyLam tv)
688 zonkCoFn env (WpTyApp ty) = do { ty' <- zonkTcTypeToType env ty
689 ; return (env, WpTyApp ty') }
690 zonkCoFn env (WpLet bs) = do { (env1, bs') <- zonkTcEvBinds env bs
691 ; return (env1, WpLet bs') }
693 -------------------------------------------------------------------------
694 zonkOverLit :: ZonkEnv -> HsOverLit TcId -> TcM (HsOverLit Id)
695 zonkOverLit env lit@(OverLit { ol_witness = e, ol_type = ty })
696 = do { ty' <- zonkTcTypeToType env ty
697 ; e' <- zonkExpr env e
698 ; return (lit { ol_witness = e', ol_type = ty' }) }
700 -------------------------------------------------------------------------
701 zonkArithSeq :: ZonkEnv -> ArithSeqInfo TcId -> TcM (ArithSeqInfo Id)
703 zonkArithSeq env (From e)
704 = zonkLExpr env e `thenM` \ new_e ->
707 zonkArithSeq env (FromThen e1 e2)
708 = zonkLExpr env e1 `thenM` \ new_e1 ->
709 zonkLExpr env e2 `thenM` \ new_e2 ->
710 returnM (FromThen new_e1 new_e2)
712 zonkArithSeq env (FromTo e1 e2)
713 = zonkLExpr env e1 `thenM` \ new_e1 ->
714 zonkLExpr env e2 `thenM` \ new_e2 ->
715 returnM (FromTo new_e1 new_e2)
717 zonkArithSeq env (FromThenTo e1 e2 e3)
718 = zonkLExpr env e1 `thenM` \ new_e1 ->
719 zonkLExpr env e2 `thenM` \ new_e2 ->
720 zonkLExpr env e3 `thenM` \ new_e3 ->
721 returnM (FromThenTo new_e1 new_e2 new_e3)
724 -------------------------------------------------------------------------
725 zonkStmts :: ZonkEnv -> [LStmt TcId] -> TcM (ZonkEnv, [LStmt Id])
726 zonkStmts env [] = return (env, [])
727 zonkStmts env (s:ss) = do { (env1, s') <- wrapLocSndM (zonkStmt env) s
728 ; (env2, ss') <- zonkStmts env1 ss
729 ; return (env2, s' : ss') }
731 zonkStmt :: ZonkEnv -> Stmt TcId -> TcM (ZonkEnv, Stmt Id)
732 zonkStmt env (ParStmt stmts_w_bndrs mzip_op bind_op return_op)
733 = mappM zonk_branch stmts_w_bndrs `thenM` \ new_stmts_w_bndrs ->
735 new_binders = concat (map snd new_stmts_w_bndrs)
736 env1 = extendZonkEnv env new_binders
738 zonkExpr env1 mzip_op `thenM` \ new_mzip ->
739 zonkExpr env1 bind_op `thenM` \ new_bind ->
740 zonkExpr env1 return_op `thenM` \ new_return ->
741 return (env1, ParStmt new_stmts_w_bndrs new_mzip new_bind new_return)
743 zonk_branch (stmts, bndrs) = zonkStmts env stmts `thenM` \ (env1, new_stmts) ->
744 returnM (new_stmts, zonkIdOccs env1 bndrs)
746 zonkStmt env (RecStmt { recS_stmts = segStmts, recS_later_ids = lvs, recS_rec_ids = rvs
747 , recS_ret_fn = ret_id, recS_mfix_fn = mfix_id, recS_bind_fn = bind_id
748 , recS_rec_rets = rets })
749 = do { new_rvs <- zonkIdBndrs env rvs
750 ; new_lvs <- zonkIdBndrs env lvs
751 ; new_ret_id <- zonkExpr env ret_id
752 ; new_mfix_id <- zonkExpr env mfix_id
753 ; new_bind_id <- zonkExpr env bind_id
754 ; let env1 = extendZonkEnv env new_rvs
755 ; (env2, new_segStmts) <- zonkStmts env1 segStmts
756 -- Zonk the ret-expressions in an envt that
757 -- has the polymorphic bindings in the envt
758 ; new_rets <- mapM (zonkExpr env2) rets
759 ; return (extendZonkEnv env new_lvs, -- Only the lvs are needed
760 RecStmt { recS_stmts = new_segStmts, recS_later_ids = new_lvs
761 , recS_rec_ids = new_rvs, recS_ret_fn = new_ret_id
762 , recS_mfix_fn = new_mfix_id, recS_bind_fn = new_bind_id
763 , recS_rec_rets = new_rets }) }
765 zonkStmt env (ExprStmt expr then_op guard_op ty)
766 = zonkLExpr env expr `thenM` \ new_expr ->
767 zonkExpr env then_op `thenM` \ new_then ->
768 zonkExpr env guard_op `thenM` \ new_guard ->
769 zonkTcTypeToType env ty `thenM` \ new_ty ->
770 returnM (env, ExprStmt new_expr new_then new_guard new_ty)
772 zonkStmt env (TransformStmt stmts binders usingExpr maybeByExpr return_op bind_op)
773 = do { (env', stmts') <- zonkStmts env stmts
774 ; let binders' = zonkIdOccs env' binders
775 ; usingExpr' <- zonkLExpr env' usingExpr
776 ; maybeByExpr' <- zonkMaybeLExpr env' maybeByExpr
777 ; return_op' <- zonkExpr env' return_op
778 ; bind_op' <- zonkExpr env' bind_op
779 ; return (env', TransformStmt stmts' binders' usingExpr' maybeByExpr' return_op' bind_op') }
781 zonkStmt env (GroupStmt stmts binderMap by using return_op bind_op liftM_op)
782 = do { (env', stmts') <- zonkStmts env stmts
783 ; binderMap' <- mappM (zonkBinderMapEntry env') binderMap
784 ; by' <- fmapMaybeM (zonkLExpr env') by
785 ; using' <- fmapEitherM (zonkLExpr env) (zonkExpr env) using
786 ; return_op' <- zonkExpr env' return_op
787 ; bind_op' <- zonkExpr env' bind_op
788 ; liftM_op' <- zonkExpr env' liftM_op
789 ; let env'' = extendZonkEnv env' (map snd binderMap')
790 ; return (env'', GroupStmt stmts' binderMap' by' using' return_op' bind_op' liftM_op') }
792 zonkBinderMapEntry env (oldBinder, newBinder) = do
793 let oldBinder' = zonkIdOcc env oldBinder
794 newBinder' <- zonkIdBndr env newBinder
795 return (oldBinder', newBinder')
797 zonkStmt env (LetStmt binds)
798 = zonkLocalBinds env binds `thenM` \ (env1, new_binds) ->
799 returnM (env1, LetStmt new_binds)
801 zonkStmt env (BindStmt pat expr bind_op fail_op)
802 = do { new_expr <- zonkLExpr env expr
803 ; (env1, new_pat) <- zonkPat env pat
804 ; new_bind <- zonkExpr env bind_op
805 ; new_fail <- zonkExpr env fail_op
806 ; return (env1, BindStmt new_pat new_expr new_bind new_fail) }
808 zonkMaybeLExpr :: ZonkEnv -> Maybe (LHsExpr TcId) -> TcM (Maybe (LHsExpr Id))
809 zonkMaybeLExpr _ Nothing = return Nothing
810 zonkMaybeLExpr env (Just e) = (zonkLExpr env e) >>= (return . Just)
813 -------------------------------------------------------------------------
814 zonkRecFields :: ZonkEnv -> HsRecordBinds TcId -> TcM (HsRecordBinds TcId)
815 zonkRecFields env (HsRecFields flds dd)
816 = do { flds' <- mappM zonk_rbind flds
817 ; return (HsRecFields flds' dd) }
820 = do { new_id <- wrapLocM (zonkIdBndr env) (hsRecFieldId fld)
821 ; new_expr <- zonkLExpr env (hsRecFieldArg fld)
822 ; return (fld { hsRecFieldId = new_id, hsRecFieldArg = new_expr }) }
824 -------------------------------------------------------------------------
825 mapIPNameTc :: (a -> TcM b) -> IPName a -> TcM (IPName b)
826 mapIPNameTc f (IPName n) = f n `thenM` \ r -> returnM (IPName r)
830 %************************************************************************
832 \subsection[BackSubst-Pats]{Patterns}
834 %************************************************************************
837 zonkPat :: ZonkEnv -> OutPat TcId -> TcM (ZonkEnv, OutPat Id)
838 -- Extend the environment as we go, because it's possible for one
839 -- pattern to bind something that is used in another (inside or
841 zonkPat env pat = wrapLocSndM (zonk_pat env) pat
843 zonk_pat :: ZonkEnv -> Pat TcId -> TcM (ZonkEnv, Pat Id)
844 zonk_pat env (ParPat p)
845 = do { (env', p') <- zonkPat env p
846 ; return (env', ParPat p') }
848 zonk_pat env (WildPat ty)
849 = do { ty' <- zonkTcTypeToType env ty
850 ; return (env, WildPat ty') }
852 zonk_pat env (VarPat v)
853 = do { v' <- zonkIdBndr env v
854 ; return (extendZonkEnv1 env v', VarPat v') }
856 zonk_pat env (LazyPat pat)
857 = do { (env', pat') <- zonkPat env pat
858 ; return (env', LazyPat pat') }
860 zonk_pat env (BangPat pat)
861 = do { (env', pat') <- zonkPat env pat
862 ; return (env', BangPat pat') }
864 zonk_pat env (AsPat (L loc v) pat)
865 = do { v' <- zonkIdBndr env v
866 ; (env', pat') <- zonkPat (extendZonkEnv1 env v') pat
867 ; return (env', AsPat (L loc v') pat') }
869 zonk_pat env (ViewPat expr pat ty)
870 = do { expr' <- zonkLExpr env expr
871 ; (env', pat') <- zonkPat env pat
872 ; ty' <- zonkTcTypeToType env ty
873 ; return (env', ViewPat expr' pat' ty') }
875 zonk_pat env (ListPat pats ty)
876 = do { ty' <- zonkTcTypeToType env ty
877 ; (env', pats') <- zonkPats env pats
878 ; return (env', ListPat pats' ty') }
880 zonk_pat env (PArrPat pats ty)
881 = do { ty' <- zonkTcTypeToType env ty
882 ; (env', pats') <- zonkPats env pats
883 ; return (env', PArrPat pats' ty') }
885 zonk_pat env (TuplePat pats boxed ty)
886 = do { ty' <- zonkTcTypeToType env ty
887 ; (env', pats') <- zonkPats env pats
888 ; return (env', TuplePat pats' boxed ty') }
890 zonk_pat env p@(ConPatOut { pat_ty = ty, pat_dicts = evs, pat_binds = binds, pat_args = args })
891 = ASSERT( all isImmutableTyVar (pat_tvs p) )
892 do { new_ty <- zonkTcTypeToType env ty
893 ; (env1, new_evs) <- zonkEvBndrsX env evs
894 ; (env2, new_binds) <- zonkTcEvBinds env1 binds
895 ; (env', new_args) <- zonkConStuff env2 args
896 ; returnM (env', p { pat_ty = new_ty, pat_dicts = new_evs,
897 pat_binds = new_binds, pat_args = new_args }) }
899 zonk_pat env (LitPat lit) = return (env, LitPat lit)
901 zonk_pat env (SigPatOut pat ty)
902 = do { ty' <- zonkTcTypeToType env ty
903 ; (env', pat') <- zonkPat env pat
904 ; return (env', SigPatOut pat' ty') }
906 zonk_pat env (NPat lit mb_neg eq_expr)
907 = do { lit' <- zonkOverLit env lit
908 ; mb_neg' <- fmapMaybeM (zonkExpr env) mb_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 zonkVects :: ZonkEnv -> [LVectDecl TcId] -> TcM [LVectDecl Id]
1023 zonkVects env = mappM (wrapLocM (zonkVect env))
1025 zonkVect :: ZonkEnv -> VectDecl TcId -> TcM (VectDecl Id)
1026 zonkVect env (HsVect v Nothing)
1027 = do { v' <- wrapLocM (zonkIdBndr env) v
1028 ; return $ HsVect v' Nothing
1030 zonkVect env (HsVect v (Just e))
1031 = do { v' <- wrapLocM (zonkIdBndr env) v
1032 ; e' <- zonkLExpr env e
1033 ; return $ HsVect v' (Just e')
1037 %************************************************************************
1039 Constraints and evidence
1041 %************************************************************************
1044 zonkEvTerm :: ZonkEnv -> EvTerm -> TcM EvTerm
1045 zonkEvTerm env (EvId v) = ASSERT2( isId v, ppr v )
1046 return (EvId (zonkIdOcc env v))
1047 zonkEvTerm env (EvCoercion co) = do { co' <- zonkTcTypeToType env co
1048 ; return (EvCoercion co') }
1049 zonkEvTerm env (EvCast v co) = ASSERT( isId v)
1050 do { co' <- zonkTcTypeToType env co
1051 ; return (EvCast (zonkIdOcc env v) co') }
1052 zonkEvTerm env (EvSuperClass d n) = return (EvSuperClass (zonkIdOcc env d) n)
1053 zonkEvTerm env (EvDFunApp df tys tms)
1054 = do { tys' <- zonkTcTypeToTypes env tys
1055 ; let tms' = map (zonkEvVarOcc env) tms
1056 ; return (EvDFunApp (zonkIdOcc env df) tys' tms') }
1058 zonkTcEvBinds :: ZonkEnv -> TcEvBinds -> TcM (ZonkEnv, TcEvBinds)
1059 zonkTcEvBinds env (TcEvBinds var) = do { (env', bs') <- zonkEvBindsVar env var
1060 ; return (env', EvBinds bs') }
1061 zonkTcEvBinds env (EvBinds bs) = do { (env', bs') <- zonkEvBinds env bs
1062 ; return (env', EvBinds bs') }
1064 zonkEvBindsVar :: ZonkEnv -> EvBindsVar -> TcM (ZonkEnv, Bag EvBind)
1065 zonkEvBindsVar env (EvBindsVar ref _) = do { bs <- readMutVar ref
1066 ; zonkEvBinds env (evBindMapBinds bs) }
1068 zonkEvBinds :: ZonkEnv -> Bag EvBind -> TcM (ZonkEnv, Bag EvBind)
1069 zonkEvBinds env binds
1070 = fixM (\ ~( _, new_binds) -> do
1071 { let env1 = extendZonkEnv env (collect_ev_bndrs new_binds)
1072 ; binds' <- mapBagM (zonkEvBind env1) binds
1073 ; return (env1, binds') })
1075 collect_ev_bndrs :: Bag EvBind -> [EvVar]
1076 collect_ev_bndrs = foldrBag add []
1077 add (EvBind var _) vars = var : vars
1079 zonkEvBind :: ZonkEnv -> EvBind -> TcM EvBind
1080 zonkEvBind env (EvBind var term)
1081 = do { var' <- zonkEvBndr env var
1082 ; term' <- zonkEvTerm env term
1083 ; return (EvBind var' term') }
1086 %************************************************************************
1090 %************************************************************************
1093 zonkTcTypeToType :: ZonkEnv -> TcType -> TcM Type
1094 zonkTcTypeToType (ZonkEnv zonk_ty _) ty = zonk_ty ty
1096 zonkTcTypeToTypes :: ZonkEnv -> [TcType] -> TcM [Type]
1097 zonkTcTypeToTypes env tys = mapM (zonkTcTypeToType env) tys
1099 zonkTypeCollecting :: TcRef TyVarSet -> TcType -> TcM Type
1100 -- This variant collects unbound type variables in a mutable variable
1101 zonkTypeCollecting unbound_tv_set
1102 = zonkType (mkZonkTcTyVar zonk_unbound_tyvar)
1104 zonk_unbound_tyvar tv
1105 = do { tv' <- zonkQuantifiedTyVar tv
1106 ; tv_set <- readMutVar unbound_tv_set
1107 ; writeMutVar unbound_tv_set (extendVarSet tv_set tv')
1108 ; return (mkTyVarTy tv') }
1110 zonkTypeZapping :: TcType -> TcM Type
1111 -- This variant is used for everything except the LHS of rules
1112 -- It zaps unbound type variables to (), or some other arbitrary type
1114 = zonkType (mkZonkTcTyVar zonk_unbound_tyvar) ty
1116 -- Zonk a mutable but unbound type variable to an arbitrary type
1117 -- We know it's unbound even though we don't carry an environment,
1118 -- because at the binding site for a type variable we bind the
1119 -- mutable tyvar to a fresh immutable one. So the mutable store
1120 -- plays the role of an environment. If we come across a mutable
1121 -- type variable that isn't so bound, it must be completely free.
1122 zonk_unbound_tyvar tv = do { let ty = anyTypeOfKind (tyVarKind tv)
1123 ; writeMetaTyVar tv ty