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
47 import DynFlags( DynFlag(..) )
55 import Data.Traversable( traverse )
60 thenM :: Monad a => a b -> (b -> a c) -> a c
63 returnM :: Monad m => a -> m a
66 mappM :: (Monad m) => (a -> m b) -> [a] -> m [b]
71 %************************************************************************
73 \subsection[mkFailurePair]{Code for pattern-matching and other failures}
75 %************************************************************************
77 Note: If @hsLPatType@ doesn't bear a strong resemblance to @exprType@,
78 then something is wrong.
80 hsLPatType :: OutPat Id -> Type
81 hsLPatType (L _ pat) = hsPatType pat
83 hsPatType :: Pat Id -> Type
84 hsPatType (ParPat pat) = hsLPatType pat
85 hsPatType (WildPat ty) = ty
86 hsPatType (VarPat var) = idType var
87 hsPatType (BangPat pat) = hsLPatType pat
88 hsPatType (LazyPat pat) = hsLPatType pat
89 hsPatType (LitPat lit) = hsLitType lit
90 hsPatType (AsPat var _) = idType (unLoc var)
91 hsPatType (ViewPat _ _ ty) = ty
92 hsPatType (ListPat _ ty) = mkListTy ty
93 hsPatType (PArrPat _ ty) = mkPArrTy ty
94 hsPatType (TuplePat _ _ ty) = ty
95 hsPatType (ConPatOut { pat_ty = ty }) = ty
96 hsPatType (SigPatOut _ ty) = ty
97 hsPatType (NPat lit _ _) = overLitType lit
98 hsPatType (NPlusKPat id _ _ _) = idType (unLoc id)
99 hsPatType (CoPat _ _ ty) = ty
100 hsPatType p = pprPanic "hsPatType" (ppr p)
102 hsLitType :: HsLit -> TcType
103 hsLitType (HsChar _) = charTy
104 hsLitType (HsCharPrim _) = charPrimTy
105 hsLitType (HsString _) = stringTy
106 hsLitType (HsStringPrim _) = addrPrimTy
107 hsLitType (HsInt _) = intTy
108 hsLitType (HsIntPrim _) = intPrimTy
109 hsLitType (HsWordPrim _) = wordPrimTy
110 hsLitType (HsInteger _ ty) = ty
111 hsLitType (HsRat _ ty) = ty
112 hsLitType (HsFloatPrim _) = floatPrimTy
113 hsLitType (HsDoublePrim _) = doublePrimTy
116 Overloaded literals. Here mainly becuase it uses isIntTy etc
119 shortCutLit :: OverLitVal -> TcType -> Maybe (HsExpr TcId)
120 shortCutLit (HsIntegral i) ty
121 | isIntTy ty && inIntRange i = Just (HsLit (HsInt i))
122 | isWordTy ty && inWordRange i = Just (mkLit wordDataCon (HsWordPrim i))
123 | isIntegerTy ty = Just (HsLit (HsInteger i ty))
124 | otherwise = shortCutLit (HsFractional (fromInteger i)) ty
125 -- The 'otherwise' case is important
126 -- Consider (3 :: Float). Syntactically it looks like an IntLit,
127 -- so we'll call shortCutIntLit, but of course it's a float
128 -- This can make a big difference for programs with a lot of
129 -- literals, compiled without -O
131 shortCutLit (HsFractional f) ty
132 | isFloatTy ty = Just (mkLit floatDataCon (HsFloatPrim f))
133 | isDoubleTy ty = Just (mkLit doubleDataCon (HsDoublePrim f))
134 | otherwise = Nothing
136 shortCutLit (HsIsString s) ty
137 | isStringTy ty = Just (HsLit (HsString s))
138 | otherwise = Nothing
140 mkLit :: DataCon -> HsLit -> HsExpr Id
141 mkLit con lit = HsApp (nlHsVar (dataConWrapId con)) (nlHsLit lit)
143 ------------------------------
144 hsOverLitName :: OverLitVal -> Name
145 -- Get the canonical 'fromX' name for a particular OverLitVal
146 hsOverLitName (HsIntegral {}) = fromIntegerName
147 hsOverLitName (HsFractional {}) = fromRationalName
148 hsOverLitName (HsIsString {}) = fromStringName
151 %************************************************************************
153 \subsection[BackSubst-HsBinds]{Running a substitution over @HsBinds@}
155 %************************************************************************
158 -- zonkId is used *during* typechecking just to zonk the Id's type
159 zonkId :: TcId -> TcM TcId
161 = zonkTcType (idType id) `thenM` \ ty' ->
162 returnM (Id.setIdType id ty')
165 The rest of the zonking is done *after* typechecking.
166 The main zonking pass runs over the bindings
168 a) to convert TcTyVars to TyVars etc, dereferencing any bindings etc
169 b) convert unbound TcTyVar to Void
170 c) convert each TcId to an Id by zonking its type
172 The type variables are converted by binding mutable tyvars to immutable ones
173 and then zonking as normal.
175 The Ids are converted by binding them in the normal Tc envt; that
176 way we maintain sharing; eg an Id is zonked at its binding site and they
177 all occurrences of that Id point to the common zonked copy
179 It's all pretty boring stuff, because HsSyn is such a large type, and
180 the environment manipulation is tiresome.
183 data ZonkEnv = ZonkEnv (TcType -> TcM Type) -- How to zonk a type
184 (VarEnv Var) -- What variables are in scope
185 -- Maps an Id or EvVar to its zonked version; both have the same Name
186 -- Note that all evidence (coercion variables as well as dictionaries)
187 -- are kept in the ZonkEnv
188 -- Only *type* abstraction is done by side effect
189 -- Is only consulted lazily; hence knot-tying
191 emptyZonkEnv :: ZonkEnv
192 emptyZonkEnv = ZonkEnv zonkTypeZapping emptyVarEnv
194 extendZonkEnv :: ZonkEnv -> [Var] -> ZonkEnv
195 extendZonkEnv (ZonkEnv zonk_ty env) ids
196 = ZonkEnv zonk_ty (extendVarEnvList env [(id,id) | id <- ids])
198 extendZonkEnv1 :: ZonkEnv -> Var -> ZonkEnv
199 extendZonkEnv1 (ZonkEnv zonk_ty env) id
200 = ZonkEnv zonk_ty (extendVarEnv env id id)
202 setZonkType :: ZonkEnv -> (TcType -> TcM Type) -> ZonkEnv
203 setZonkType (ZonkEnv _ env) zonk_ty = ZonkEnv zonk_ty env
205 zonkEnvIds :: ZonkEnv -> [Id]
206 zonkEnvIds (ZonkEnv _ env) = varEnvElts env
208 zonkIdOcc :: ZonkEnv -> TcId -> Id
209 -- Ids defined in this module should be in the envt;
210 -- ignore others. (Actually, data constructors are also
211 -- not LocalVars, even when locally defined, but that is fine.)
212 -- (Also foreign-imported things aren't currently in the ZonkEnv;
213 -- that's ok because they don't need zonking.)
215 -- Actually, Template Haskell works in 'chunks' of declarations, and
216 -- an earlier chunk won't be in the 'env' that the zonking phase
217 -- carries around. Instead it'll be in the tcg_gbl_env, already fully
218 -- zonked. There's no point in looking it up there (except for error
219 -- checking), and it's not conveniently to hand; hence the simple
220 -- 'orElse' case in the LocalVar branch.
222 -- Even without template splices, in module Main, the checking of
223 -- 'main' is done as a separate chunk.
224 zonkIdOcc (ZonkEnv _zonk_ty env) id
225 | isLocalVar id = lookupVarEnv env id `orElse` id
228 zonkIdOccs :: ZonkEnv -> [TcId] -> [Id]
229 zonkIdOccs env ids = map (zonkIdOcc env) ids
231 -- zonkIdBndr is used *after* typechecking to get the Id's type
232 -- to its final form. The TyVarEnv give
233 zonkIdBndr :: ZonkEnv -> TcId -> TcM Id
235 = zonkTcTypeToType env (idType id) `thenM` \ ty' ->
236 returnM (Id.setIdType id ty')
238 zonkIdBndrs :: ZonkEnv -> [TcId] -> TcM [Id]
239 zonkIdBndrs env ids = mappM (zonkIdBndr env) ids
241 zonkTopBndrs :: [TcId] -> TcM [Id]
242 zonkTopBndrs ids = zonkIdBndrs emptyZonkEnv ids
244 zonkEvBndrsX :: ZonkEnv -> [EvVar] -> TcM (ZonkEnv, [Var])
245 zonkEvBndrsX = mapAccumLM zonkEvBndrX
247 zonkEvBndrX :: ZonkEnv -> EvVar -> TcM (ZonkEnv, EvVar)
248 -- Works for dictionaries and coercions
250 = do { var' <- zonkEvBndr env var
251 ; return (extendZonkEnv1 env var', var') }
253 zonkEvBndr :: ZonkEnv -> EvVar -> TcM EvVar
254 -- Works for dictionaries and coercions
255 -- Does not extend the ZonkEnv
257 = do { ty' <- zonkTcTypeToType env (varType var)
258 ; return (setVarType var ty') }
260 zonkEvVarOcc :: ZonkEnv -> EvVar -> EvVar
261 zonkEvVarOcc env v = zonkIdOcc env v
266 zonkTopExpr :: HsExpr TcId -> TcM (HsExpr Id)
267 zonkTopExpr e = zonkExpr emptyZonkEnv e
269 zonkTopLExpr :: LHsExpr TcId -> TcM (LHsExpr Id)
270 zonkTopLExpr e = zonkLExpr emptyZonkEnv e
272 zonkTopDecls :: Bag EvBind
273 -> LHsBinds TcId -> NameSet
274 -> [LRuleDecl TcId] -> [LVectDecl TcId] -> [LTcSpecPrag] -> [LForeignDecl TcId]
282 zonkTopDecls ev_binds binds sig_ns rules vects imp_specs fords
283 = do { (env1, ev_binds') <- zonkEvBinds emptyZonkEnv ev_binds
285 -- Warn about missing signatures
286 -- Do this only when we we have a type to offer
287 ; warn_missing_sigs <- doptM Opt_WarnMissingSigs
288 ; let sig_warn | warn_missing_sigs = topSigWarn sig_ns
289 | otherwise = noSigWarn
291 ; (env2, binds') <- zonkRecMonoBinds env1 sig_warn binds
292 -- Top level is implicitly recursive
293 ; rules' <- zonkRules env2 rules
294 ; vects' <- zonkVects env2 vects
295 ; specs' <- zonkLTcSpecPrags env2 imp_specs
296 ; fords' <- zonkForeignExports env2 fords
297 ; return (zonkEnvIds env2, ev_binds', binds', fords', specs', rules', vects') }
299 ---------------------------------------------
300 zonkLocalBinds :: ZonkEnv -> HsLocalBinds TcId -> TcM (ZonkEnv, HsLocalBinds Id)
301 zonkLocalBinds env EmptyLocalBinds
302 = return (env, EmptyLocalBinds)
304 zonkLocalBinds _ (HsValBinds (ValBindsIn {}))
305 = panic "zonkLocalBinds" -- Not in typechecker output
307 zonkLocalBinds env (HsValBinds vb@(ValBindsOut binds sigs))
308 = do { warn_missing_sigs <- doptM Opt_WarnMissingLocalSigs
309 ; let sig_warn | not warn_missing_sigs = noSigWarn
310 | otherwise = localSigWarn sig_ns
311 sig_ns = getTypeSigNames vb
312 ; (env1, new_binds) <- go env sig_warn binds
313 ; return (env1, HsValBinds (ValBindsOut new_binds sigs)) }
317 go env sig_warn ((r,b):bs)
318 = do { (env1, b') <- zonkRecMonoBinds env sig_warn b
319 ; (env2, bs') <- go env1 sig_warn bs
320 ; return (env2, (r,b'):bs') }
322 zonkLocalBinds env (HsIPBinds (IPBinds binds dict_binds))
323 = mappM (wrapLocM zonk_ip_bind) binds `thenM` \ new_binds ->
325 env1 = extendZonkEnv env [ipNameName n | L _ (IPBind n _) <- new_binds]
327 zonkTcEvBinds env1 dict_binds `thenM` \ (env2, new_dict_binds) ->
328 returnM (env2, HsIPBinds (IPBinds new_binds new_dict_binds))
330 zonk_ip_bind (IPBind n e)
331 = mapIPNameTc (zonkIdBndr env) n `thenM` \ n' ->
332 zonkLExpr env e `thenM` \ e' ->
333 returnM (IPBind n' e')
335 ---------------------------------------------
336 zonkRecMonoBinds :: ZonkEnv -> SigWarn -> LHsBinds TcId -> TcM (ZonkEnv, LHsBinds Id)
337 zonkRecMonoBinds env sig_warn binds
338 = fixM (\ ~(_, new_binds) -> do
339 { let env1 = extendZonkEnv env (collectHsBindsBinders new_binds)
340 ; binds' <- zonkMonoBinds env1 sig_warn binds
341 ; return (env1, binds') })
343 ---------------------------------------------
344 type SigWarn = Bool -> [Id] -> TcM ()
345 -- Missing-signature warning
346 -- The Bool is True for an AbsBinds, False otherwise
349 noSigWarn _ _ = return ()
351 topSigWarn :: NameSet -> SigWarn
352 topSigWarn sig_ns _ ids = mapM_ (topSigWarnId sig_ns) ids
354 topSigWarnId :: NameSet -> Id -> TcM ()
355 -- The NameSet is the Ids that *lack* a signature
356 -- We have to do it this way round because there are
357 -- lots of top-level bindings that are generated by GHC
358 -- and that don't have signatures
359 topSigWarnId sig_ns id
360 | idName id `elemNameSet` sig_ns = warnMissingSig msg id
361 | otherwise = return ()
363 msg = ptext (sLit "Top-level binding with no type signature:")
365 localSigWarn :: NameSet -> SigWarn
366 localSigWarn sig_ns is_abs_bind ids
367 | not is_abs_bind = return ()
368 | otherwise = mapM_ (localSigWarnId sig_ns) ids
370 localSigWarnId :: NameSet -> Id -> TcM ()
371 -- NameSet are the Ids that *have* type signatures
372 localSigWarnId sig_ns id
373 | not (isSigmaTy (idType id)) = return ()
374 | idName id `elemNameSet` sig_ns = return ()
375 | otherwise = warnMissingSig msg id
377 msg = ptext (sLit "Polymophic local binding with no type signature:")
379 warnMissingSig :: SDoc -> Id -> TcM ()
380 warnMissingSig msg id
381 = do { env0 <- tcInitTidyEnv
382 ; let (env1, tidy_ty) = tidyOpenType env0 (idType id)
383 ; addWarnTcM (env1, mk_msg tidy_ty) }
385 mk_msg ty = sep [ msg, nest 2 $ pprHsVar (idName id) <+> dcolon <+> ppr ty ]
387 ---------------------------------------------
388 zonkMonoBinds :: ZonkEnv -> SigWarn -> LHsBinds TcId -> TcM (LHsBinds Id)
389 zonkMonoBinds env sig_warn binds = mapBagM (wrapLocM (zonk_bind env sig_warn)) binds
391 zonk_bind :: ZonkEnv -> SigWarn -> HsBind TcId -> TcM (HsBind Id)
392 zonk_bind env sig_warn bind@(PatBind { pat_lhs = pat, pat_rhs = grhss, pat_rhs_ty = ty})
393 = do { (_env, new_pat) <- zonkPat env pat -- Env already extended
394 ; sig_warn False (collectPatBinders new_pat)
395 ; new_grhss <- zonkGRHSs env grhss
396 ; new_ty <- zonkTcTypeToType env ty
397 ; return (bind { pat_lhs = new_pat, pat_rhs = new_grhss, pat_rhs_ty = new_ty }) }
399 zonk_bind env sig_warn (VarBind { var_id = var, var_rhs = expr, var_inline = inl })
400 = do { new_var <- zonkIdBndr env var
401 ; sig_warn False [new_var]
402 ; new_expr <- zonkLExpr env expr
403 ; return (VarBind { var_id = new_var, var_rhs = new_expr, var_inline = inl }) }
405 zonk_bind env sig_warn bind@(FunBind { fun_id = L loc var, fun_matches = ms
406 , fun_co_fn = co_fn })
407 = do { new_var <- zonkIdBndr env var
408 ; sig_warn False [new_var]
409 ; (env1, new_co_fn) <- zonkCoFn env co_fn
410 ; new_ms <- zonkMatchGroup env1 ms
411 ; return (bind { fun_id = L loc new_var, fun_matches = new_ms
412 , fun_co_fn = new_co_fn }) }
414 zonk_bind env sig_warn (AbsBinds { abs_tvs = tyvars, abs_ev_vars = evs
415 , abs_ev_binds = ev_binds
416 , abs_exports = exports
417 , abs_binds = val_binds })
418 = ASSERT( all isImmutableTyVar tyvars )
419 do { (env1, new_evs) <- zonkEvBndrsX env evs
420 ; (env2, new_ev_binds) <- zonkTcEvBinds env1 ev_binds
421 ; (new_val_bind, new_exports) <- fixM $ \ ~(new_val_binds, _) ->
422 do { let env3 = extendZonkEnv env2 (collectHsBindsBinders new_val_binds)
423 ; new_val_binds <- zonkMonoBinds env3 noSigWarn val_binds
424 ; new_exports <- mapM (zonkExport env3) exports
425 ; return (new_val_binds, new_exports) }
426 ; sig_warn True [b | (_,b,_,_) <- new_exports]
427 ; return (AbsBinds { abs_tvs = tyvars, abs_ev_vars = new_evs, abs_ev_binds = new_ev_binds
428 , abs_exports = new_exports, abs_binds = new_val_bind }) }
430 zonkExport env (tyvars, global, local, prags)
431 -- The tyvars are already zonked
432 = zonkIdBndr env global `thenM` \ new_global ->
433 zonkSpecPrags env prags `thenM` \ new_prags ->
434 returnM (tyvars, new_global, zonkIdOcc env local, new_prags)
436 zonkSpecPrags :: ZonkEnv -> TcSpecPrags -> TcM TcSpecPrags
437 zonkSpecPrags _ IsDefaultMethod = return IsDefaultMethod
438 zonkSpecPrags env (SpecPrags ps) = do { ps' <- zonkLTcSpecPrags env ps
439 ; return (SpecPrags ps') }
441 zonkLTcSpecPrags :: ZonkEnv -> [LTcSpecPrag] -> TcM [LTcSpecPrag]
442 zonkLTcSpecPrags env ps
445 zonk_prag (L loc (SpecPrag id co_fn inl))
446 = do { (_, co_fn') <- zonkCoFn env co_fn
447 ; return (L loc (SpecPrag (zonkIdOcc env id) co_fn' inl)) }
450 %************************************************************************
452 \subsection[BackSubst-Match-GRHSs]{Match and GRHSs}
454 %************************************************************************
457 zonkMatchGroup :: ZonkEnv -> MatchGroup TcId-> TcM (MatchGroup Id)
458 zonkMatchGroup env (MatchGroup ms ty)
459 = do { ms' <- mapM (zonkMatch env) ms
460 ; ty' <- zonkTcTypeToType env ty
461 ; return (MatchGroup ms' ty') }
463 zonkMatch :: ZonkEnv -> LMatch TcId-> TcM (LMatch Id)
464 zonkMatch env (L loc (Match pats _ grhss))
465 = do { (env1, new_pats) <- zonkPats env pats
466 ; new_grhss <- zonkGRHSs env1 grhss
467 ; return (L loc (Match new_pats Nothing new_grhss)) }
469 -------------------------------------------------------------------------
470 zonkGRHSs :: ZonkEnv -> GRHSs TcId -> TcM (GRHSs Id)
472 zonkGRHSs env (GRHSs grhss binds)
473 = zonkLocalBinds env binds `thenM` \ (new_env, new_binds) ->
475 zonk_grhs (GRHS guarded rhs)
476 = zonkStmts new_env guarded `thenM` \ (env2, new_guarded) ->
477 zonkLExpr env2 rhs `thenM` \ new_rhs ->
478 returnM (GRHS new_guarded new_rhs)
480 mappM (wrapLocM zonk_grhs) grhss `thenM` \ new_grhss ->
481 returnM (GRHSs new_grhss new_binds)
484 %************************************************************************
486 \subsection[BackSubst-HsExpr]{Running a zonkitution over a TypeCheckedExpr}
488 %************************************************************************
491 zonkLExprs :: ZonkEnv -> [LHsExpr TcId] -> TcM [LHsExpr Id]
492 zonkLExpr :: ZonkEnv -> LHsExpr TcId -> TcM (LHsExpr Id)
493 zonkExpr :: ZonkEnv -> HsExpr TcId -> TcM (HsExpr Id)
495 zonkLExprs env exprs = mappM (zonkLExpr env) exprs
496 zonkLExpr env expr = wrapLocM (zonkExpr env) expr
498 zonkExpr env (HsVar id)
499 = returnM (HsVar (zonkIdOcc env id))
501 zonkExpr env (HsIPVar id)
502 = returnM (HsIPVar (mapIPName (zonkIdOcc env) id))
504 zonkExpr env (HsLit (HsRat f ty))
505 = zonkTcTypeToType env ty `thenM` \ new_ty ->
506 returnM (HsLit (HsRat f new_ty))
508 zonkExpr _ (HsLit lit)
509 = returnM (HsLit lit)
511 zonkExpr env (HsOverLit lit)
512 = do { lit' <- zonkOverLit env lit
513 ; return (HsOverLit lit') }
515 zonkExpr env (HsLam matches)
516 = zonkMatchGroup env matches `thenM` \ new_matches ->
517 returnM (HsLam new_matches)
519 zonkExpr env (HsApp e1 e2)
520 = zonkLExpr env e1 `thenM` \ new_e1 ->
521 zonkLExpr env e2 `thenM` \ new_e2 ->
522 returnM (HsApp new_e1 new_e2)
524 zonkExpr env (HsBracketOut body bs)
525 = mappM zonk_b bs `thenM` \ bs' ->
526 returnM (HsBracketOut body bs')
528 zonk_b (n,e) = zonkLExpr env e `thenM` \ e' ->
531 zonkExpr _ (HsSpliceE s) = WARN( True, ppr s ) -- Should not happen
532 returnM (HsSpliceE s)
534 zonkExpr env (OpApp e1 op fixity e2)
535 = zonkLExpr env e1 `thenM` \ new_e1 ->
536 zonkLExpr env op `thenM` \ new_op ->
537 zonkLExpr env e2 `thenM` \ new_e2 ->
538 returnM (OpApp new_e1 new_op fixity new_e2)
540 zonkExpr env (NegApp expr op)
541 = zonkLExpr env expr `thenM` \ new_expr ->
542 zonkExpr env op `thenM` \ new_op ->
543 returnM (NegApp new_expr new_op)
545 zonkExpr env (HsPar e)
546 = zonkLExpr env e `thenM` \new_e ->
547 returnM (HsPar new_e)
549 zonkExpr env (SectionL expr op)
550 = zonkLExpr env expr `thenM` \ new_expr ->
551 zonkLExpr env op `thenM` \ new_op ->
552 returnM (SectionL new_expr new_op)
554 zonkExpr env (SectionR op expr)
555 = zonkLExpr env op `thenM` \ new_op ->
556 zonkLExpr env expr `thenM` \ new_expr ->
557 returnM (SectionR new_op new_expr)
559 zonkExpr env (ExplicitTuple tup_args boxed)
560 = do { new_tup_args <- mapM zonk_tup_arg tup_args
561 ; return (ExplicitTuple new_tup_args boxed) }
563 zonk_tup_arg (Present e) = do { e' <- zonkLExpr env e; return (Present e') }
564 zonk_tup_arg (Missing t) = do { t' <- zonkTcTypeToType env t; return (Missing t') }
566 zonkExpr env (HsCase expr ms)
567 = zonkLExpr env expr `thenM` \ new_expr ->
568 zonkMatchGroup env ms `thenM` \ new_ms ->
569 returnM (HsCase new_expr new_ms)
571 zonkExpr env (HsIf e0 e1 e2 e3)
572 = do { new_e0 <- fmapMaybeM (zonkExpr env) e0
573 ; new_e1 <- zonkLExpr env e1
574 ; new_e2 <- zonkLExpr env e2
575 ; new_e3 <- zonkLExpr env e3
576 ; returnM (HsIf new_e0 new_e1 new_e2 new_e3) }
578 zonkExpr env (HsLet binds expr)
579 = zonkLocalBinds env binds `thenM` \ (new_env, new_binds) ->
580 zonkLExpr new_env expr `thenM` \ new_expr ->
581 returnM (HsLet new_binds new_expr)
583 zonkExpr env (HsDo do_or_lc stmts body ty)
584 = zonkStmts env stmts `thenM` \ (new_env, new_stmts) ->
585 zonkLExpr new_env body `thenM` \ new_body ->
586 zonkTcTypeToType env ty `thenM` \ new_ty ->
587 returnM (HsDo do_or_lc new_stmts new_body new_ty)
589 zonkExpr env (ExplicitList ty exprs)
590 = zonkTcTypeToType env ty `thenM` \ new_ty ->
591 zonkLExprs env exprs `thenM` \ new_exprs ->
592 returnM (ExplicitList new_ty new_exprs)
594 zonkExpr env (ExplicitPArr ty exprs)
595 = zonkTcTypeToType env ty `thenM` \ new_ty ->
596 zonkLExprs env exprs `thenM` \ new_exprs ->
597 returnM (ExplicitPArr new_ty new_exprs)
599 zonkExpr env (RecordCon data_con con_expr rbinds)
600 = do { new_con_expr <- zonkExpr env con_expr
601 ; new_rbinds <- zonkRecFields env rbinds
602 ; return (RecordCon data_con new_con_expr new_rbinds) }
604 zonkExpr env (RecordUpd expr rbinds cons in_tys out_tys)
605 = do { new_expr <- zonkLExpr env expr
606 ; new_in_tys <- mapM (zonkTcTypeToType env) in_tys
607 ; new_out_tys <- mapM (zonkTcTypeToType env) out_tys
608 ; new_rbinds <- zonkRecFields env rbinds
609 ; return (RecordUpd new_expr new_rbinds cons new_in_tys new_out_tys) }
611 zonkExpr env (ExprWithTySigOut e ty)
612 = do { e' <- zonkLExpr env e
613 ; return (ExprWithTySigOut e' ty) }
615 zonkExpr _ (ExprWithTySig _ _) = panic "zonkExpr env:ExprWithTySig"
617 zonkExpr env (ArithSeq expr info)
618 = zonkExpr env expr `thenM` \ new_expr ->
619 zonkArithSeq env info `thenM` \ new_info ->
620 returnM (ArithSeq new_expr new_info)
622 zonkExpr env (PArrSeq expr info)
623 = zonkExpr env expr `thenM` \ new_expr ->
624 zonkArithSeq env info `thenM` \ new_info ->
625 returnM (PArrSeq new_expr new_info)
627 zonkExpr env (HsSCC lbl expr)
628 = zonkLExpr env expr `thenM` \ new_expr ->
629 returnM (HsSCC lbl new_expr)
631 zonkExpr env (HsTickPragma info expr)
632 = zonkLExpr env expr `thenM` \ new_expr ->
633 returnM (HsTickPragma info new_expr)
635 -- hdaume: core annotations
636 zonkExpr env (HsCoreAnn lbl expr)
637 = zonkLExpr env expr `thenM` \ new_expr ->
638 returnM (HsCoreAnn lbl new_expr)
640 -- arrow notation extensions
641 zonkExpr env (HsProc pat body)
642 = do { (env1, new_pat) <- zonkPat env pat
643 ; new_body <- zonkCmdTop env1 body
644 ; return (HsProc new_pat new_body) }
646 zonkExpr env (HsArrApp e1 e2 ty ho rl)
647 = zonkLExpr env e1 `thenM` \ new_e1 ->
648 zonkLExpr env e2 `thenM` \ new_e2 ->
649 zonkTcTypeToType env ty `thenM` \ new_ty ->
650 returnM (HsArrApp new_e1 new_e2 new_ty ho rl)
652 zonkExpr env (HsArrForm op fixity args)
653 = zonkLExpr env op `thenM` \ new_op ->
654 mappM (zonkCmdTop env) args `thenM` \ new_args ->
655 returnM (HsArrForm new_op fixity new_args)
657 zonkExpr env (HsWrap co_fn expr)
658 = zonkCoFn env co_fn `thenM` \ (env1, new_co_fn) ->
659 zonkExpr env1 expr `thenM` \ new_expr ->
660 return (HsWrap new_co_fn new_expr)
662 zonkExpr _ expr = pprPanic "zonkExpr" (ppr expr)
664 zonkCmdTop :: ZonkEnv -> LHsCmdTop TcId -> TcM (LHsCmdTop Id)
665 zonkCmdTop env cmd = wrapLocM (zonk_cmd_top env) cmd
667 zonk_cmd_top :: ZonkEnv -> HsCmdTop TcId -> TcM (HsCmdTop Id)
668 zonk_cmd_top env (HsCmdTop cmd stack_tys ty ids)
669 = zonkLExpr env cmd `thenM` \ new_cmd ->
670 zonkTcTypeToTypes env stack_tys `thenM` \ new_stack_tys ->
671 zonkTcTypeToType env ty `thenM` \ new_ty ->
672 mapSndM (zonkExpr env) ids `thenM` \ new_ids ->
673 returnM (HsCmdTop new_cmd new_stack_tys new_ty new_ids)
675 -------------------------------------------------------------------------
676 zonkCoFn :: ZonkEnv -> HsWrapper -> TcM (ZonkEnv, HsWrapper)
677 zonkCoFn env WpHole = return (env, WpHole)
678 zonkCoFn env (WpCompose c1 c2) = do { (env1, c1') <- zonkCoFn env c1
679 ; (env2, c2') <- zonkCoFn env1 c2
680 ; return (env2, WpCompose c1' c2') }
681 zonkCoFn env (WpCast co) = do { co' <- zonkTcCoToCo env co
682 ; return (env, WpCast co') }
683 zonkCoFn env (WpEvLam ev) = do { (env', ev') <- zonkEvBndrX env ev
684 ; return (env', WpEvLam ev') }
685 zonkCoFn env (WpEvApp arg) = do { arg' <- zonkEvTerm env arg
686 ; return (env, WpEvApp arg') }
687 zonkCoFn env (WpTyLam tv) = ASSERT( isImmutableTyVar tv )
688 return (env, WpTyLam tv)
689 zonkCoFn env (WpTyApp ty) = do { ty' <- zonkTcTypeToType env ty
690 ; return (env, WpTyApp ty') }
691 zonkCoFn env (WpLet bs) = do { (env1, bs') <- zonkTcEvBinds env bs
692 ; return (env1, WpLet bs') }
694 -------------------------------------------------------------------------
695 zonkOverLit :: ZonkEnv -> HsOverLit TcId -> TcM (HsOverLit Id)
696 zonkOverLit env lit@(OverLit { ol_witness = e, ol_type = ty })
697 = do { ty' <- zonkTcTypeToType env ty
698 ; e' <- zonkExpr env e
699 ; return (lit { ol_witness = e', ol_type = ty' }) }
701 -------------------------------------------------------------------------
702 zonkArithSeq :: ZonkEnv -> ArithSeqInfo TcId -> TcM (ArithSeqInfo Id)
704 zonkArithSeq env (From e)
705 = zonkLExpr env e `thenM` \ new_e ->
708 zonkArithSeq env (FromThen e1 e2)
709 = zonkLExpr env e1 `thenM` \ new_e1 ->
710 zonkLExpr env e2 `thenM` \ new_e2 ->
711 returnM (FromThen new_e1 new_e2)
713 zonkArithSeq env (FromTo e1 e2)
714 = zonkLExpr env e1 `thenM` \ new_e1 ->
715 zonkLExpr env e2 `thenM` \ new_e2 ->
716 returnM (FromTo new_e1 new_e2)
718 zonkArithSeq env (FromThenTo e1 e2 e3)
719 = zonkLExpr env e1 `thenM` \ new_e1 ->
720 zonkLExpr env e2 `thenM` \ new_e2 ->
721 zonkLExpr env e3 `thenM` \ new_e3 ->
722 returnM (FromThenTo new_e1 new_e2 new_e3)
725 -------------------------------------------------------------------------
726 zonkStmts :: ZonkEnv -> [LStmt TcId] -> TcM (ZonkEnv, [LStmt Id])
727 zonkStmts env [] = return (env, [])
728 zonkStmts env (s:ss) = do { (env1, s') <- wrapLocSndM (zonkStmt env) s
729 ; (env2, ss') <- zonkStmts env1 ss
730 ; return (env2, s' : ss') }
732 zonkStmt :: ZonkEnv -> Stmt TcId -> TcM (ZonkEnv, Stmt Id)
733 zonkStmt env (ParStmt stmts_w_bndrs)
734 = mappM zonk_branch stmts_w_bndrs `thenM` \ new_stmts_w_bndrs ->
736 new_binders = concat (map snd new_stmts_w_bndrs)
737 env1 = extendZonkEnv env new_binders
739 return (env1, ParStmt new_stmts_w_bndrs)
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 })
747 = do { new_rvs <- zonkIdBndrs env rvs
748 ; new_lvs <- zonkIdBndrs env lvs
749 ; new_ret_id <- zonkExpr env ret_id
750 ; new_mfix_id <- zonkExpr env mfix_id
751 ; new_bind_id <- zonkExpr env bind_id
752 ; let env1 = extendZonkEnv env new_rvs
753 ; (env2, new_segStmts) <- zonkStmts env1 segStmts
754 -- Zonk the ret-expressions in an envt that
755 -- has the polymorphic bindings in the envt
756 ; new_rets <- mapM (zonkExpr env2) rets
757 ; return (extendZonkEnv env new_lvs, -- Only the lvs are needed
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 }) }
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 (LazyPat pat)
849 = do { (env', pat') <- zonkPat env pat
850 ; return (env', LazyPat pat') }
852 zonk_pat env (BangPat pat)
853 = do { (env', pat') <- zonkPat env pat
854 ; return (env', BangPat pat') }
856 zonk_pat env (AsPat (L loc v) pat)
857 = do { v' <- zonkIdBndr env v
858 ; (env', pat') <- zonkPat (extendZonkEnv1 env v') pat
859 ; return (env', AsPat (L loc v') pat') }
861 zonk_pat env (ViewPat expr pat ty)
862 = do { expr' <- zonkLExpr env expr
863 ; (env', pat') <- zonkPat env pat
864 ; ty' <- zonkTcTypeToType env ty
865 ; return (env', ViewPat expr' pat' ty') }
867 zonk_pat env (ListPat pats ty)
868 = do { ty' <- zonkTcTypeToType env ty
869 ; (env', pats') <- zonkPats env pats
870 ; return (env', ListPat pats' ty') }
872 zonk_pat env (PArrPat pats ty)
873 = do { ty' <- zonkTcTypeToType env ty
874 ; (env', pats') <- zonkPats env pats
875 ; return (env', PArrPat pats' ty') }
877 zonk_pat env (TuplePat pats boxed ty)
878 = do { ty' <- zonkTcTypeToType env ty
879 ; (env', pats') <- zonkPats env pats
880 ; return (env', TuplePat pats' boxed ty') }
882 zonk_pat env p@(ConPatOut { pat_ty = ty, pat_dicts = evs, pat_binds = binds, pat_args = args })
883 = ASSERT( all isImmutableTyVar (pat_tvs p) )
884 do { new_ty <- zonkTcTypeToType env ty
885 ; (env1, new_evs) <- zonkEvBndrsX env evs
886 ; (env2, new_binds) <- zonkTcEvBinds env1 binds
887 ; (env', new_args) <- zonkConStuff env2 args
888 ; returnM (env', p { pat_ty = new_ty, pat_dicts = new_evs,
889 pat_binds = new_binds, pat_args = new_args }) }
891 zonk_pat env (LitPat lit) = return (env, LitPat lit)
893 zonk_pat env (SigPatOut pat ty)
894 = do { ty' <- zonkTcTypeToType env ty
895 ; (env', pat') <- zonkPat env pat
896 ; return (env', SigPatOut pat' ty') }
898 zonk_pat env (NPat lit mb_neg eq_expr)
899 = do { lit' <- zonkOverLit env lit
900 ; mb_neg' <- fmapMaybeM (zonkExpr env) mb_neg
901 ; eq_expr' <- zonkExpr env eq_expr
902 ; return (env, NPat lit' mb_neg' eq_expr') }
904 zonk_pat env (NPlusKPat (L loc n) lit e1 e2)
905 = do { n' <- zonkIdBndr env n
906 ; lit' <- zonkOverLit env lit
907 ; e1' <- zonkExpr env e1
908 ; e2' <- zonkExpr env e2
909 ; return (extendZonkEnv1 env n', NPlusKPat (L loc n') lit' e1' e2') }
911 zonk_pat env (CoPat co_fn pat ty)
912 = do { (env', co_fn') <- zonkCoFn env co_fn
913 ; (env'', pat') <- zonkPat env' (noLoc pat)
914 ; ty' <- zonkTcTypeToType env'' ty
915 ; return (env'', CoPat co_fn' (unLoc pat') ty') }
917 zonk_pat _ pat = pprPanic "zonk_pat" (ppr pat)
919 ---------------------------
920 zonkConStuff :: ZonkEnv
921 -> HsConDetails (OutPat TcId) (HsRecFields id (OutPat TcId))
923 HsConDetails (OutPat Id) (HsRecFields id (OutPat Id)))
924 zonkConStuff env (PrefixCon pats)
925 = do { (env', pats') <- zonkPats env pats
926 ; return (env', PrefixCon pats') }
928 zonkConStuff env (InfixCon p1 p2)
929 = do { (env1, p1') <- zonkPat env p1
930 ; (env', p2') <- zonkPat env1 p2
931 ; return (env', InfixCon p1' p2') }
933 zonkConStuff env (RecCon (HsRecFields rpats dd))
934 = do { (env', pats') <- zonkPats env (map hsRecFieldArg rpats)
935 ; let rpats' = zipWith (\rp p' -> rp { hsRecFieldArg = p' }) rpats pats'
936 ; returnM (env', RecCon (HsRecFields rpats' dd)) }
937 -- Field selectors have declared types; hence no zonking
939 ---------------------------
940 zonkPats :: ZonkEnv -> [OutPat TcId] -> TcM (ZonkEnv, [OutPat Id])
941 zonkPats env [] = return (env, [])
942 zonkPats env (pat:pats) = do { (env1, pat') <- zonkPat env pat
943 ; (env', pats') <- zonkPats env1 pats
944 ; return (env', pat':pats') }
947 %************************************************************************
949 \subsection[BackSubst-Foreign]{Foreign exports}
951 %************************************************************************
955 zonkForeignExports :: ZonkEnv -> [LForeignDecl TcId] -> TcM [LForeignDecl Id]
956 zonkForeignExports env ls = mappM (wrapLocM (zonkForeignExport env)) ls
958 zonkForeignExport :: ZonkEnv -> ForeignDecl TcId -> TcM (ForeignDecl Id)
959 zonkForeignExport env (ForeignExport i _hs_ty spec) =
960 returnM (ForeignExport (fmap (zonkIdOcc env) i) undefined spec)
961 zonkForeignExport _ for_imp
962 = returnM for_imp -- Foreign imports don't need zonking
966 zonkRules :: ZonkEnv -> [LRuleDecl TcId] -> TcM [LRuleDecl Id]
967 zonkRules env rs = mappM (wrapLocM (zonkRule env)) rs
969 zonkRule :: ZonkEnv -> RuleDecl TcId -> TcM (RuleDecl Id)
970 zonkRule env (HsRule name act (vars{-::[RuleBndr TcId]-}) lhs fv_lhs rhs fv_rhs)
971 = do { (env_rhs, new_bndrs) <- mapAccumLM zonk_bndr env vars
973 ; unbound_tv_set <- newMutVar emptyVarSet
974 ; let env_lhs = setZonkType env_rhs (zonkTypeCollecting unbound_tv_set)
975 -- We need to gather the type variables mentioned on the LHS so we can
976 -- quantify over them. Example:
982 -- {-# RULES "myrule" foo C = 1 #-}
984 -- After type checking the LHS becomes (foo a (C a))
985 -- and we do not want to zap the unbound tyvar 'a' to (), because
986 -- that limits the applicability of the rule. Instead, we
987 -- want to quantify over it!
989 -- It's easiest to find the free tyvars here. Attempts to do so earlier
990 -- are tiresome, because (a) the data type is big and (b) finding the
991 -- free type vars of an expression is necessarily monadic operation.
992 -- (consider /\a -> f @ b, where b is side-effected to a)
994 ; new_lhs <- zonkLExpr env_lhs lhs
995 ; new_rhs <- zonkLExpr env_rhs rhs
997 ; unbound_tvs <- readMutVar unbound_tv_set
998 ; let final_bndrs :: [RuleBndr Var]
999 final_bndrs = map (RuleBndr . noLoc) (varSetElems unbound_tvs) ++ new_bndrs
1001 ; return (HsRule name act final_bndrs new_lhs fv_lhs new_rhs fv_rhs) }
1003 zonk_bndr env (RuleBndr (L loc v))
1004 = do { (env', v') <- zonk_it env v; return (env', RuleBndr (L loc v')) }
1005 zonk_bndr _ (RuleBndrSig {}) = panic "zonk_bndr RuleBndrSig"
1008 | isId v = do { v' <- zonkIdBndr env v; return (extendZonkEnv1 env v', v') }
1009 | otherwise = ASSERT( isImmutableTyVar v) return (env, v)
1013 zonkVects :: ZonkEnv -> [LVectDecl TcId] -> TcM [LVectDecl Id]
1014 zonkVects env = mappM (wrapLocM (zonkVect env))
1016 zonkVect :: ZonkEnv -> VectDecl TcId -> TcM (VectDecl Id)
1017 zonkVect env (HsVect v Nothing)
1018 = do { v' <- wrapLocM (zonkIdBndr env) v
1019 ; return $ HsVect v' Nothing
1021 zonkVect env (HsVect v (Just e))
1022 = do { v' <- wrapLocM (zonkIdBndr env) v
1023 ; e' <- zonkLExpr env e
1024 ; return $ HsVect v' (Just e')
1028 %************************************************************************
1030 Constraints and evidence
1032 %************************************************************************
1035 zonkEvTerm :: ZonkEnv -> EvTerm -> TcM EvTerm
1036 zonkEvTerm env (EvId v) = ASSERT2( isId v, ppr v )
1037 return (EvId (zonkIdOcc env v))
1038 zonkEvTerm env (EvCoercion co) = do { co' <- zonkTcCoToCo env co
1039 ; return (EvCoercion co') }
1040 zonkEvTerm env (EvCast v co) = ASSERT( isId v)
1041 do { co' <- zonkTcCoToCo env co
1042 ; return (EvCast (zonkIdOcc env v) co') }
1043 zonkEvTerm env (EvSuperClass d n) = return (EvSuperClass (zonkIdOcc env d) n)
1044 zonkEvTerm env (EvDFunApp df tys tms)
1045 = do { tys' <- zonkTcTypeToTypes env tys
1046 ; let tms' = map (zonkEvVarOcc env) tms
1047 ; return (EvDFunApp (zonkIdOcc env df) tys' tms') }
1049 zonkTcEvBinds :: ZonkEnv -> TcEvBinds -> TcM (ZonkEnv, TcEvBinds)
1050 zonkTcEvBinds env (TcEvBinds var) = do { (env', bs') <- zonkEvBindsVar env var
1051 ; return (env', EvBinds bs') }
1052 zonkTcEvBinds env (EvBinds bs) = do { (env', bs') <- zonkEvBinds env bs
1053 ; return (env', EvBinds bs') }
1055 zonkEvBindsVar :: ZonkEnv -> EvBindsVar -> TcM (ZonkEnv, Bag EvBind)
1056 zonkEvBindsVar env (EvBindsVar ref _) = do { bs <- readMutVar ref
1057 ; zonkEvBinds env (evBindMapBinds bs) }
1059 zonkEvBinds :: ZonkEnv -> Bag EvBind -> TcM (ZonkEnv, Bag EvBind)
1060 zonkEvBinds env binds
1061 = fixM (\ ~( _, new_binds) -> do
1062 { let env1 = extendZonkEnv env (collect_ev_bndrs new_binds)
1063 ; binds' <- mapBagM (zonkEvBind env1) binds
1064 ; return (env1, binds') })
1066 collect_ev_bndrs :: Bag EvBind -> [EvVar]
1067 collect_ev_bndrs = foldrBag add []
1068 add (EvBind var _) vars = var : vars
1070 zonkEvBind :: ZonkEnv -> EvBind -> TcM EvBind
1071 zonkEvBind env (EvBind var term)
1072 = do { var' <- zonkEvBndr env var
1073 ; term' <- zonkEvTerm env term
1074 ; return (EvBind var' term') }
1077 %************************************************************************
1081 %************************************************************************
1084 zonkTcTypeToType :: ZonkEnv -> TcType -> TcM Type
1085 zonkTcTypeToType (ZonkEnv zonk_ty _) ty = zonk_ty ty
1087 zonkTcTypeToTypes :: ZonkEnv -> [TcType] -> TcM [Type]
1088 zonkTcTypeToTypes env tys = mapM (zonkTcTypeToType env) tys
1090 zonkTypeCollecting :: TcRef TyVarSet -> TcType -> TcM Type
1091 -- This variant collects unbound type variables in a mutable variable
1092 zonkTypeCollecting unbound_tv_set
1093 = zonkType (mkZonkTcTyVar zonk_unbound_tyvar)
1095 zonk_unbound_tyvar tv
1096 = do { tv' <- zonkQuantifiedTyVar tv
1097 ; tv_set <- readMutVar unbound_tv_set
1098 ; writeMutVar unbound_tv_set (extendVarSet tv_set tv')
1099 ; return (mkTyVarTy tv') }
1101 zonkTypeZapping :: TcType -> TcM Type
1102 -- This variant is used for everything except the LHS of rules
1103 -- It zaps unbound type variables to (), or some other arbitrary type
1105 = zonkType (mkZonkTcTyVar zonk_unbound_tyvar) ty
1107 -- Zonk a mutable but unbound type variable to an arbitrary type
1108 -- We know it's unbound even though we don't carry an environment,
1109 -- because at the binding site for a type variable we bind the
1110 -- mutable tyvar to a fresh immutable one. So the mutable store
1111 -- plays the role of an environment. If we come across a mutable
1112 -- type variable that isn't so bound, it must be completely free.
1113 zonk_unbound_tyvar tv = do { let ty = anyTypeOfKind (tyVarKind tv)
1114 ; writeMetaTyVar tv ty
1117 zonkTcCoToCo :: ZonkEnv -> Coercion -> TcM Coercion
1121 go (CoVarCo cv) = return (CoVarCo (zonkEvVarOcc env cv))
1122 go (Refl ty) = do { ty' <- zonkTcTypeToType env ty
1123 ; return (Refl ty') }
1124 go (TyConAppCo tc cos) = do { cos' <- mapM go cos; return (mkTyConAppCo tc cos') }
1125 go (AxiomInstCo ax cos) = do { cos' <- mapM go cos; return (AxiomInstCo ax cos') }
1126 go (AppCo co1 co2) = do { co1' <- go co1; co2' <- go co2
1127 ; return (mkAppCo co1' co2') }
1128 go (PredCo pco) = do { pco' <- go `traverse` pco; return (mkPredCo pco') }
1129 go (UnsafeCo t1 t2) = do { t1' <- zonkTcTypeToType env t1
1130 ; t2' <- zonkTcTypeToType env t2
1131 ; return (mkUnsafeCo t1' t2') }
1132 go (SymCo co) = do { co' <- go co; return (mkSymCo co') }
1133 go (NthCo n co) = do { co' <- go co; return (mkNthCo n co') }
1134 go (TransCo co1 co2) = do { co1' <- go co1; co2' <- go co2
1135 ; return (mkTransCo co1' co2') }
1136 go (InstCo co ty) = do { co' <- go co; ty' <- zonkTcTypeToType env ty
1137 ; return (mkInstCo co' ty') }
1138 go (ForAllCo tv co) = ASSERT( isImmutableTyVar tv )
1139 do { co' <- go co; return (mkForAllCo tv co') }