2 % (c) The GRASP/AQUA Project, Glasgow University, 1993-1998
4 \section[CoreLint]{A ``lint'' pass to check for Core correctness}
13 #include "HsVersions.h"
16 import CoreFVs ( idFreeVars )
17 import CoreUtils ( findDefault, exprOkForSpeculation, coreBindsSize )
19 import Literal ( literalType )
20 import DataCon ( dataConRepType, dataConTyCon, dataConWorkId )
21 import TysWiredIn ( tupleCon )
22 import Var ( Var, Id, TyVar, isCoVar, idType, tyVarKind,
23 mustHaveLocalBinding, setTyVarKind, setIdType )
24 import VarEnv ( lookupInScope )
26 import Name ( getSrcLoc )
28 import ErrUtils ( dumpIfSet_core, ghcExit, Message, showPass,
29 mkLocMessage, debugTraceMsg )
30 import SrcLoc ( SrcLoc, noSrcLoc, mkSrcSpan )
31 import Type ( Type, tyVarsOfType, coreEqType,
32 splitFunTy_maybe, mkTyVarTys,
33 splitForAllTy_maybe, splitTyConApp_maybe,
34 isUnLiftedType, typeKind, mkForAllTy, mkFunTy,
35 isUnboxedTupleType, isSubKind,
36 substTyWith, emptyTvSubst, extendTvInScope,
37 TvSubst, TvSubstEnv, mkTvSubst, setTvSubstEnv, substTy,
38 extendTvSubst, composeTvSubst, substTyVarBndr, isInScope,
39 getTvSubstEnv, getTvInScope, mkTyVarTy )
40 import Coercion ( Coercion, coercionKind, coercionKindTyConApp )
41 import TyCon ( isPrimTyCon )
42 import BasicTypes ( RecFlag(..), Boxity(..), isNonRec )
43 import StaticFlags ( opt_PprStyle_Debug )
44 import DynFlags ( DynFlags, DynFlag(..), dopt )
48 import Util ( notNull )
55 %************************************************************************
59 %************************************************************************
61 @showPass@ and @endPass@ don't really belong here, but it makes a convenient
62 place for them. They print out stuff before and after core passes,
63 and do Core Lint when necessary.
66 endPass :: DynFlags -> String -> DynFlag -> [CoreBind] -> IO [CoreBind]
67 endPass dflags pass_name dump_flag binds
69 -- Report result size if required
70 -- This has the side effect of forcing the intermediate to be evaluated
71 debugTraceMsg dflags 2 $
72 (text " Result size =" <+> int (coreBindsSize binds))
74 -- Report verbosely, if required
75 dumpIfSet_core dflags dump_flag pass_name (pprCoreBindings binds)
78 lintCoreBindings dflags pass_name binds
84 %************************************************************************
86 \subsection[lintCoreBindings]{@lintCoreBindings@: Top-level interface}
88 %************************************************************************
90 Checks that a set of core bindings is well-formed. The PprStyle and String
91 just control what we print in the event of an error. The Bool value
92 indicates whether we have done any specialisation yet (in which case we do
97 (b) Out-of-scope type variables
98 (c) Out-of-scope local variables
101 If we have done specialisation the we check that there are
102 (a) No top-level bindings of primitive (unboxed type)
107 -- Things are *not* OK if:
109 -- * Unsaturated type app before specialisation has been done;
111 -- * Oversaturated type app after specialisation (eta reduction
112 -- may well be happening...);
117 In the desugarer, it's very very convenient to be able to say (in effect)
118 let a = Int in <body>
119 That is, use a type let. (See notes just below for why we want this.)
121 We don't have type lets in Core, so the desugarer uses type lambda
123 However, in the lambda form, we'd get lint errors from:
124 (/\a. let x::a = 4 in <body>) Int
125 because (x::a) doesn't look compatible with (4::Int).
127 So (HACK ALERT) the Lint phase does type-beta reduction "on the fly",
128 as it were. It carries a type substitution (in this example [a -> Int])
129 and applies this substitution before comparing types. The functin
130 lintTy :: Type -> LintM Type
131 returns a substituted type; that's the only reason it returns anything.
133 When we encounter a binder (like x::a) we must apply the substitution
134 to the type of the binding variable. lintBinders does this.
136 For Ids, the type-substituted Id is added to the in_scope set (which
137 itself is part of the TvSubst we are carrying down), and when we
138 find an occurence of an Id, we fetch it from the in-scope set.
143 It's needed when dealing with desugarer output for GADTs. Consider
144 data T = forall a. T a (a->Int) Bool
146 f (T x f True) = <e1>
147 f (T y g False) = <e2>
148 After desugaring we get
150 T a (x::a) (f::a->Int) (b:Bool) ->
153 False -> (/\b. let y=x; g=f in <e2>) a
154 And for a reason I now forget, the ...<e2>... can mention a; so
155 we want Lint to know that b=a. Ugh.
157 I tried quite hard to make the necessity for this go away, by changing the
158 desugarer, but the fundamental problem is this:
160 T a (x::a) (y::Int) -> let fail::a = ...
161 in (/\b. ...(case ... of
165 Now the inner case look as though it has incompatible branches.
169 lintCoreBindings :: DynFlags -> String -> [CoreBind] -> IO ()
171 lintCoreBindings dflags whoDunnit binds
172 | not (dopt Opt_DoCoreLinting dflags)
175 lintCoreBindings dflags whoDunnit binds
176 = case (initL (lint_binds binds)) of
177 Nothing -> showPass dflags ("Core Linted result of " ++ whoDunnit)
178 Just bad_news -> printDump (display bad_news) >>
181 -- Put all the top-level binders in scope at the start
182 -- This is because transformation rules can bring something
183 -- into use 'unexpectedly'
184 lint_binds binds = addInScopeVars (bindersOfBinds binds) $
187 lint_bind (Rec prs) = mapM_ (lintSingleBinding Recursive) prs
188 lint_bind (NonRec bndr rhs) = lintSingleBinding NonRecursive (bndr,rhs)
191 = vcat [ text ("*** Core Lint Errors: in result of " ++ whoDunnit ++ " ***"),
193 ptext SLIT("*** Offending Program ***"),
194 pprCoreBindings binds,
195 ptext SLIT("*** End of Offense ***")
199 %************************************************************************
201 \subsection[lintUnfolding]{lintUnfolding}
203 %************************************************************************
205 We use this to check all unfoldings that come in from interfaces
206 (it is very painful to catch errors otherwise):
209 lintUnfolding :: SrcLoc
210 -> [Var] -- Treat these as in scope
212 -> Maybe Message -- Nothing => OK
214 lintUnfolding locn vars expr
215 = initL (addLoc (ImportedUnfolding locn) $
216 addInScopeVars vars $
220 %************************************************************************
222 \subsection[lintCoreBinding]{lintCoreBinding}
224 %************************************************************************
226 Check a core binding, returning the list of variables bound.
229 lintSingleBinding rec_flag (binder,rhs)
230 = addLoc (RhsOf binder) $
232 do { ty <- lintCoreExpr rhs
233 ; lintBinder binder -- Check match to RHS type
234 ; binder_ty <- applySubst binder_ty
235 ; checkTys binder_ty ty (mkRhsMsg binder ty)
236 -- Check (not isUnLiftedType) (also checks for bogus unboxed tuples)
237 ; checkL (not (isUnLiftedType binder_ty)
238 || (isNonRec rec_flag && exprOkForSpeculation rhs))
239 (mkRhsPrimMsg binder rhs)
240 -- Check whether binder's specialisations contain any out-of-scope variables
241 ; mapM_ (checkBndrIdInScope binder) bndr_vars }
243 -- We should check the unfolding, if any, but this is tricky because
244 -- the unfolding is a SimplifiableCoreExpr. Give up for now.
246 binder_ty = idType binder
247 bndr_vars = varSetElems (idFreeVars binder)
248 lintBinder var | isId var = lintIdBndr var $ \_ -> (return ())
249 | otherwise = return ()
252 %************************************************************************
254 \subsection[lintCoreExpr]{lintCoreExpr}
256 %************************************************************************
259 type InType = Type -- Substitution not yet applied
260 type OutType = Type -- Substitution has been applied to this
262 lintCoreExpr :: CoreExpr -> LintM OutType
263 -- The returned type has the substitution from the monad
264 -- already applied to it:
265 -- lintCoreExpr e subst = exprType (subst e)
267 lintCoreExpr (Var var)
268 = do { checkL (not (var == oneTupleDataConId))
269 (ptext SLIT("Illegal one-tuple"))
270 ; var' <- lookupIdInScope var
271 ; return (idType var')
274 lintCoreExpr (Lit lit)
275 = return (literalType lit)
277 --lintCoreExpr (Note (Coerce to_ty from_ty) expr)
278 -- = do { expr_ty <- lintCoreExpr expr
279 -- ; to_ty <- lintTy to_ty
280 -- ; from_ty <- lintTy from_ty
281 -- ; checkTys from_ty expr_ty (mkCoerceErr from_ty expr_ty)
284 lintCoreExpr (Cast expr co)
285 = do { expr_ty <- lintCoreExpr expr
287 ; let (from_ty, to_ty) = coercionKind co'
288 ; checkTys from_ty expr_ty (mkCastErr from_ty expr_ty)
291 lintCoreExpr (Note other_note expr)
294 lintCoreExpr (Let (NonRec bndr rhs) body)
295 = do { lintSingleBinding NonRecursive (bndr,rhs)
296 ; addLoc (BodyOfLetRec [bndr])
297 (lintAndScopeId bndr $ \_ -> (lintCoreExpr body)) }
299 lintCoreExpr (Let (Rec pairs) body)
300 = lintAndScopeIds bndrs $ \_ ->
301 do { mapM (lintSingleBinding Recursive) pairs
302 ; addLoc (BodyOfLetRec bndrs) (lintCoreExpr body) }
304 bndrs = map fst pairs
306 lintCoreExpr e@(App fun (Type ty))
307 -- See Note [Type let] above
308 = addLoc (AnExpr e) $
311 go (App fun (Type ty)) tys
312 = do { go fun (ty:tys) }
313 go (Lam tv body) (ty:tys)
314 = do { checkL (isTyVar tv) (mkKindErrMsg tv ty) -- Not quite accurate
316 ; let kind = tyVarKind tv
317 ; kind' <- lintTy kind
318 ; let tv' = setTyVarKind tv kind'
320 -- Now extend the substitution so we
321 -- take advantage of it in the body
322 ; addInScopeVars [tv'] $
323 extendSubstL tv' ty' $
326 = do { fun_ty <- lintCoreExpr fun
327 ; lintCoreArgs fun_ty (map Type tys) }
329 lintCoreExpr e@(App fun arg)
330 = do { fun_ty <- lintCoreExpr fun
331 ; addLoc (AnExpr e) $
332 lintCoreArg fun_ty arg }
334 lintCoreExpr (Lam var expr)
335 = addLoc (LambdaBodyOf var) $
336 lintBinders [var] $ \[var'] ->
337 do { body_ty <- lintCoreExpr expr
339 return (mkFunTy (idType var') body_ty)
341 return (mkForAllTy var' body_ty)
343 -- The applySubst is needed to apply the subst to var
345 lintCoreExpr e@(Case scrut var alt_ty alts) =
346 -- Check the scrutinee
347 do { scrut_ty <- lintCoreExpr scrut
348 ; alt_ty <- lintTy alt_ty
349 ; var_ty <- lintTy (idType var)
350 -- Don't use lintIdBndr on var, because unboxed tuple is legitimate
352 ; subst <- getTvSubst
353 ; checkTys var_ty scrut_ty (mkScrutMsg var var_ty scrut_ty subst)
355 -- If the binder is an unboxed tuple type, don't put it in scope
356 ; let scope = if (isUnboxedTupleType (idType var)) then
358 else lintAndScopeId var
360 do { -- Check the alternatives
361 checkCaseAlts e scrut_ty alts
362 ; mapM (lintCoreAlt scrut_ty alt_ty) alts
367 lintCoreExpr e@(Type ty)
368 = addErrL (mkStrangeTyMsg e)
371 %************************************************************************
373 \subsection[lintCoreArgs]{lintCoreArgs}
375 %************************************************************************
377 The basic version of these functions checks that the argument is a
378 subtype of the required type, as one would expect.
381 lintCoreArgs :: Type -> [CoreArg] -> LintM Type
382 lintCoreArg :: Type -> CoreArg -> LintM Type
383 -- First argument has already had substitution applied to it
387 lintCoreArgs ty [] = return ty
388 lintCoreArgs ty (a : args) =
389 do { res <- lintCoreArg ty a
390 ; lintCoreArgs res args }
392 lintCoreArg fun_ty a@(Type arg_ty) =
393 do { arg_ty <- lintTy arg_ty
394 ; lintTyApp fun_ty arg_ty }
396 lintCoreArg fun_ty arg =
397 -- Make sure function type matches argument
398 do { arg_ty <- lintCoreExpr arg
399 ; let err = mkAppMsg fun_ty arg_ty arg
400 ; case splitFunTy_maybe fun_ty of
402 do { checkTys arg arg_ty err
408 -- Both args have had substitution applied
410 = case splitForAllTy_maybe ty of
411 Nothing -> addErrL (mkTyAppMsg ty arg_ty)
414 -> do { checkL (isTyVar tyvar) (mkTyAppMsg ty arg_ty)
415 ; checkKinds tyvar arg_ty
416 ; return (substTyWith [tyvar] [arg_ty] body) }
418 lintTyApps fun_ty [] = return fun_ty
420 lintTyApps fun_ty (arg_ty : arg_tys) =
421 do { fun_ty' <- lintTyApp fun_ty arg_ty
422 ; lintTyApps fun_ty' arg_tys }
424 checkKinds tyvar arg_ty
425 -- Arg type might be boxed for a function with an uncommitted
426 -- tyvar; notably this is used so that we can give
427 -- error :: forall a:*. String -> a
428 -- and then apply it to both boxed and unboxed types.
429 = checkL (arg_kind `isSubKind` tyvar_kind)
430 (mkKindErrMsg tyvar arg_ty)
432 tyvar_kind = tyVarKind tyvar
433 arg_kind | isCoVar tyvar = coercionKindTyConApp arg_ty
434 | otherwise = typeKind arg_ty
438 %************************************************************************
440 \subsection[lintCoreAlts]{lintCoreAlts}
442 %************************************************************************
445 checkCaseAlts :: CoreExpr -> OutType -> [CoreAlt] -> LintM ()
446 -- a) Check that the alts are non-empty
447 -- b1) Check that the DEFAULT comes first, if it exists
448 -- b2) Check that the others are in increasing order
449 -- c) Check that there's a default for infinite types
450 -- NB: Algebraic cases are not necessarily exhaustive, because
451 -- the simplifer correctly eliminates case that can't
454 checkCaseAlts e ty []
455 = addErrL (mkNullAltsMsg e)
457 checkCaseAlts e ty alts =
458 do { checkL (all non_deflt con_alts) (mkNonDefltMsg e)
459 ; checkL (increasing_tag con_alts) (mkNonIncreasingAltsMsg e)
460 ; checkL (isJust maybe_deflt || not is_infinite_ty)
461 (nonExhaustiveAltsMsg e) }
463 (con_alts, maybe_deflt) = findDefault alts
465 -- Check that successive alternatives have increasing tags
466 increasing_tag (alt1 : rest@( alt2 : _)) = alt1 `ltAlt` alt2 && increasing_tag rest
467 increasing_tag other = True
469 non_deflt (DEFAULT, _, _) = False
472 is_infinite_ty = case splitTyConApp_maybe ty of
474 Just (tycon, tycon_arg_tys) -> isPrimTyCon tycon
478 checkAltExpr :: CoreExpr -> OutType -> LintM ()
479 checkAltExpr expr ann_ty
480 = do { actual_ty <- lintCoreExpr expr
481 ; checkTys actual_ty ann_ty (mkCaseAltMsg expr actual_ty ann_ty) }
483 lintCoreAlt :: OutType -- Type of scrutinee
484 -> OutType -- Type of the alternative
488 lintCoreAlt scrut_ty alt_ty alt@(DEFAULT, args, rhs) =
489 do { checkL (null args) (mkDefaultArgsMsg args)
490 ; checkAltExpr rhs alt_ty }
492 lintCoreAlt scrut_ty alt_ty alt@(LitAlt lit, args, rhs) =
493 do { checkL (null args) (mkDefaultArgsMsg args)
494 ; checkTys lit_ty scrut_ty (mkBadPatMsg lit_ty scrut_ty)
495 ; checkAltExpr rhs alt_ty }
497 lit_ty = literalType lit
499 lintCoreAlt scrut_ty alt_ty alt@(DataAlt con, args, rhs)
500 | Just (tycon, tycon_arg_tys) <- splitTyConApp_maybe scrut_ty
501 = addLoc (CaseAlt alt) $ lintBinders args $ \ args ->
503 do { addLoc (CasePat alt) $ do
504 { -- Check the pattern
505 -- Scrutinee type must be a tycon applicn; checked by caller
506 -- This code is remarkably compact considering what it does!
507 -- NB: args must be in scope here so that the lintCoreArgs line works.
508 -- NB: relies on existential type args coming *after* ordinary type args
511 lintCoreArgs (dataConRepType con)
512 (map Type tycon_arg_tys ++ varsToCoreExprs args)
513 ; checkTys con_result_ty scrut_ty (mkBadPatMsg con_result_ty scrut_ty)
516 ; checkAltExpr rhs alt_ty }
518 | otherwise -- Scrut-ty is wrong shape
519 = addErrL (mkBadAltMsg scrut_ty alt)
522 %************************************************************************
524 \subsection[lint-types]{Types}
526 %************************************************************************
529 -- When we lint binders, we (one at a time and in order):
530 -- 1. Lint var types or kinds (possibly substituting)
531 -- 2. Add the binder to the in scope set, and if its a coercion var,
532 -- we may extend the substitution to reflect its (possibly) new kind
533 lintBinders :: [Var] -> ([Var] -> LintM a) -> LintM a
534 lintBinders [] linterF = linterF []
535 lintBinders (var:vars) linterF = lintBinder var $ \var' ->
536 lintBinders vars $ \ vars' ->
539 lintBinder :: Var -> (Var -> LintM a) -> LintM a
540 lintBinder var linterF
541 | isTyVar var = lint_ty_bndr
542 | otherwise = lintIdBndr var linterF
544 lint_ty_bndr = do { lintTy (tyVarKind var)
545 ; subst <- getTvSubst
546 ; let (subst', tv') = substTyVarBndr subst var
547 ; updateTvSubst subst' (linterF tv') }
549 lintIdBndr :: Var -> (Var -> LintM a) -> LintM a
550 -- Do substitution on the type of a binder and add the var with this
551 -- new type to the in-scope set of the second argument
552 -- ToDo: lint its rules
553 lintIdBndr id linterF
554 = do { checkL (not (isUnboxedTupleType (idType id)))
555 (mkUnboxedTupleMsg id)
556 -- No variable can be bound to an unboxed tuple.
557 ; lintAndScopeId id $ \id' -> linterF id'
560 lintAndScopeIds :: [Var] -> ([Var] -> LintM a) -> LintM a
561 lintAndScopeIds ids linterF
565 go (id:ids) = do { lintAndScopeId id $ \id ->
566 lintAndScopeIds ids $ \ids ->
569 lintAndScopeId :: Var -> (Var -> LintM a) -> LintM a
570 lintAndScopeId id linterF
571 = do { ty <- lintTy (idType id)
572 ; let id' = setIdType id ty
573 ; addInScopeVars [id'] $ (linterF id')
576 lintTy :: InType -> LintM OutType
577 -- Check the type, and apply the substitution to it
578 -- ToDo: check the kind structure of the type
580 = do { ty' <- applySubst ty
581 ; mapM_ checkTyVarInScope (varSetElems (tyVarsOfType ty'))
586 %************************************************************************
588 \subsection[lint-monad]{The Lint monad}
590 %************************************************************************
595 [LintLocInfo] -> -- Locations
596 TvSubst -> -- Current type substitution; we also use this
597 -- to keep track of all the variables in scope,
598 -- both Ids and TyVars
599 Bag Message -> -- Error messages so far
600 (Maybe a, Bag Message) } -- Result and error messages (if any)
602 instance Monad LintM where
603 return x = LintM (\ loc subst errs -> (Just x, errs))
604 fail err = LintM (\ loc subst errs -> (Nothing, addErr subst errs (text err) loc))
605 m >>= k = LintM (\ loc subst errs ->
606 let (res, errs') = unLintM m loc subst errs in
608 Just r -> unLintM (k r) loc subst errs'
609 Nothing -> (Nothing, errs'))
612 = RhsOf Id -- The variable bound
613 | LambdaBodyOf Id -- The lambda-binder
614 | BodyOfLetRec [Id] -- One of the binders
615 | CaseAlt CoreAlt -- Case alternative
616 | CasePat CoreAlt -- *Pattern* of the case alternative
617 | AnExpr CoreExpr -- Some expression
618 | ImportedUnfolding SrcLoc -- Some imported unfolding (ToDo: say which)
623 initL :: LintM a -> Maybe Message {- errors -}
625 = case unLintM m [] emptyTvSubst emptyBag of
626 (_, errs) | isEmptyBag errs -> Nothing
627 | otherwise -> Just (vcat (punctuate (text "") (bagToList errs)))
631 checkL :: Bool -> Message -> LintM ()
632 checkL True msg = return ()
633 checkL False msg = addErrL msg
635 addErrL :: Message -> LintM a
636 addErrL msg = LintM (\ loc subst errs -> (Nothing, addErr subst errs msg loc))
638 addErr :: TvSubst -> Bag Message -> Message -> [LintLocInfo] -> Bag Message
639 addErr subst errs_so_far msg locs
640 = ASSERT( notNull locs )
641 errs_so_far `snocBag` mk_msg msg
643 (loc, cxt1) = dumpLoc (head locs)
644 cxts = [snd (dumpLoc loc) | loc <- locs]
645 context | opt_PprStyle_Debug = vcat (reverse cxts) $$ cxt1 $$
646 ptext SLIT("Substitution:") <+> ppr subst
649 mk_msg msg = mkLocMessage (mkSrcSpan loc loc) (context $$ msg)
651 addLoc :: LintLocInfo -> LintM a -> LintM a
653 LintM (\ loc subst errs -> unLintM m (extra_loc:loc) subst errs)
655 addInScopeVars :: [Var] -> LintM a -> LintM a
656 addInScopeVars vars m =
657 LintM (\ loc subst errs -> unLintM m loc (extendTvInScope subst vars) errs)
659 updateTvSubst :: TvSubst -> LintM a -> LintM a
660 updateTvSubst subst' m =
661 LintM (\ loc subst errs -> unLintM m loc subst' errs)
663 getTvSubst :: LintM TvSubst
664 getTvSubst = LintM (\ loc subst errs -> (Just subst, errs))
666 applySubst :: Type -> LintM Type
667 applySubst ty = do { subst <- getTvSubst; return (substTy subst ty) }
669 extendSubstL :: TyVar -> Type -> LintM a -> LintM a
671 = LintM (\ loc subst errs -> unLintM m loc (extendTvSubst subst tv ty) errs)
675 lookupIdInScope :: Id -> LintM Id
677 | not (mustHaveLocalBinding id)
678 = return id -- An imported Id
680 = do { subst <- getTvSubst
681 ; case lookupInScope (getTvInScope subst) id of
683 Nothing -> do { addErrL out_of_scope
686 out_of_scope = ppr id <+> ptext SLIT("is out of scope")
689 oneTupleDataConId :: Id -- Should not happen
690 oneTupleDataConId = dataConWorkId (tupleCon Boxed 1)
692 checkBndrIdInScope :: Var -> Var -> LintM ()
693 checkBndrIdInScope binder id
694 = checkInScope msg id
696 msg = ptext SLIT("is out of scope inside info for") <+>
699 checkTyVarInScope :: TyVar -> LintM ()
700 checkTyVarInScope tv = checkInScope (ptext SLIT("is out of scope")) tv
702 checkInScope :: SDoc -> Var -> LintM ()
703 checkInScope loc_msg var =
704 do { subst <- getTvSubst
705 ; checkL (not (mustHaveLocalBinding var) || (var `isInScope` subst))
706 (hsep [ppr var, loc_msg]) }
708 checkTys :: Type -> Type -> Message -> LintM ()
709 -- check ty2 is subtype of ty1 (ie, has same structure but usage
710 -- annotations need only be consistent, not equal)
711 -- Assumes ty1,ty2 are have alrady had the substitution applied
712 checkTys ty1 ty2 msg = checkL (ty1 `coreEqType` ty2) msg
715 %************************************************************************
717 \subsection{Error messages}
719 %************************************************************************
723 = (getSrcLoc v, brackets (ptext SLIT("RHS of") <+> pp_binders [v]))
725 dumpLoc (LambdaBodyOf b)
726 = (getSrcLoc b, brackets (ptext SLIT("in body of lambda with binder") <+> pp_binder b))
728 dumpLoc (BodyOfLetRec [])
729 = (noSrcLoc, brackets (ptext SLIT("In body of a letrec with no binders")))
731 dumpLoc (BodyOfLetRec bs@(_:_))
732 = ( getSrcLoc (head bs), brackets (ptext SLIT("in body of letrec with binders") <+> pp_binders bs))
735 = (noSrcLoc, text "In the expression:" <+> ppr e)
737 dumpLoc (CaseAlt (con, args, rhs))
738 = (noSrcLoc, text "In a case alternative:" <+> parens (ppr con <+> pp_binders args))
740 dumpLoc (CasePat (con, args, rhs))
741 = (noSrcLoc, text "In the pattern of a case alternative:" <+> parens (ppr con <+> pp_binders args))
743 dumpLoc (ImportedUnfolding locn)
744 = (locn, brackets (ptext SLIT("in an imported unfolding")))
746 pp_binders :: [Var] -> SDoc
747 pp_binders bs = sep (punctuate comma (map pp_binder bs))
749 pp_binder :: Var -> SDoc
750 pp_binder b | isId b = hsep [ppr b, dcolon, ppr (idType b)]
751 | isTyVar b = hsep [ppr b, dcolon, ppr (tyVarKind b)]
755 ------------------------------------------------------
756 -- Messages for case expressions
758 mkNullAltsMsg :: CoreExpr -> Message
760 = hang (text "Case expression with no alternatives:")
763 mkDefaultArgsMsg :: [Var] -> Message
764 mkDefaultArgsMsg args
765 = hang (text "DEFAULT case with binders")
768 mkCaseAltMsg :: CoreExpr -> Type -> Type -> Message
769 mkCaseAltMsg e ty1 ty2
770 = hang (text "Type of case alternatives not the same as the annotation on case:")
771 4 (vcat [ppr ty1, ppr ty2, ppr e])
773 mkScrutMsg :: Id -> Type -> Type -> TvSubst -> Message
774 mkScrutMsg var var_ty scrut_ty subst
775 = vcat [text "Result binder in case doesn't match scrutinee:" <+> ppr var,
776 text "Result binder type:" <+> ppr var_ty,--(idType var),
777 text "Scrutinee type:" <+> ppr scrut_ty,
778 hsep [ptext SLIT("Current TV subst"), ppr subst]]
782 = hang (text "Case expression with DEFAULT not at the beginnning") 4 (ppr e)
783 mkNonIncreasingAltsMsg e
784 = hang (text "Case expression with badly-ordered alternatives") 4 (ppr e)
786 nonExhaustiveAltsMsg :: CoreExpr -> Message
787 nonExhaustiveAltsMsg e
788 = hang (text "Case expression with non-exhaustive alternatives") 4 (ppr e)
790 mkBadPatMsg :: Type -> Type -> Message
791 mkBadPatMsg con_result_ty scrut_ty
793 text "In a case alternative, pattern result type doesn't match scrutinee type:",
794 text "Pattern result type:" <+> ppr con_result_ty,
795 text "Scrutinee type:" <+> ppr scrut_ty
798 mkBadAltMsg :: Type -> CoreAlt -> Message
799 mkBadAltMsg scrut_ty alt
800 = vcat [ text "Data alternative when scrutinee is not a tycon application",
801 text "Scrutinee type:" <+> ppr scrut_ty,
802 text "Alternative:" <+> pprCoreAlt alt ]
804 ------------------------------------------------------
805 -- Other error messages
807 mkAppMsg :: Type -> Type -> CoreExpr -> Message
808 mkAppMsg fun_ty arg_ty arg
809 = vcat [ptext SLIT("Argument value doesn't match argument type:"),
810 hang (ptext SLIT("Fun type:")) 4 (ppr fun_ty),
811 hang (ptext SLIT("Arg type:")) 4 (ppr arg_ty),
812 hang (ptext SLIT("Arg:")) 4 (ppr arg)]
814 mkKindErrMsg :: TyVar -> Type -> Message
815 mkKindErrMsg tyvar arg_ty
816 = vcat [ptext SLIT("Kinds don't match in type application:"),
817 hang (ptext SLIT("Type variable:"))
818 4 (ppr tyvar <+> dcolon <+> ppr (tyVarKind tyvar)),
819 hang (ptext SLIT("Arg type:"))
820 4 (ppr arg_ty <+> dcolon <+> ppr (typeKind arg_ty))]
822 mkTyAppMsg :: Type -> Type -> Message
824 = vcat [text "Illegal type application:",
825 hang (ptext SLIT("Exp type:"))
826 4 (ppr ty <+> dcolon <+> ppr (typeKind ty)),
827 hang (ptext SLIT("Arg type:"))
828 4 (ppr arg_ty <+> dcolon <+> ppr (typeKind arg_ty))]
830 mkRhsMsg :: Id -> Type -> Message
833 [hsep [ptext SLIT("The type of this binder doesn't match the type of its RHS:"),
835 hsep [ptext SLIT("Binder's type:"), ppr (idType binder)],
836 hsep [ptext SLIT("Rhs type:"), ppr ty]]
838 mkRhsPrimMsg :: Id -> CoreExpr -> Message
839 mkRhsPrimMsg binder rhs
840 = vcat [hsep [ptext SLIT("The type of this binder is primitive:"),
842 hsep [ptext SLIT("Binder's type:"), ppr (idType binder)]
845 mkUnboxedTupleMsg :: Id -> Message
846 mkUnboxedTupleMsg binder
847 = vcat [hsep [ptext SLIT("A variable has unboxed tuple type:"), ppr binder],
848 hsep [ptext SLIT("Binder's type:"), ppr (idType binder)]]
850 mkCastErr from_ty expr_ty
851 = vcat [ptext SLIT("From-type of Cast differs from type of enclosed expression"),
852 ptext SLIT("From-type:") <+> ppr from_ty,
853 ptext SLIT("Type of enclosed expr:") <+> ppr expr_ty
857 = ptext SLIT("Type where expression expected:") <+> ppr e