2 % (c) The GRASP Project, Glasgow University, 1992-2002
6 TcRn, TcM, RnM, -- The monad is opaque outside this module
8 -- Standard monadic operations
9 thenM, thenM_, returnM, failM,
11 -- Non-standard operations
12 runTcRn, fixM, tryM, ioToTcRn,
13 newMutVar, readMutVar, writeMutVar,
14 getEnv, setEnv, updEnv, unsafeInterleaveM,
16 -- The environment types
17 Env(..), TopEnv(..), TcGblEnv(..),
18 TcLclEnv(..), RnLclEnv(..),
21 RnMode(..), isInterfaceMode, isCmdLineMode,
22 EntityUsage, emptyUsages, ErrCtxt,
23 ImportAvails(..), emptyImportAvails, plusImportAvails,
24 plusAvail, pruneAvails,
25 AvailEnv, emptyAvailEnv, unitAvailEnv, plusAvailEnv,
26 mkAvailEnv, lookupAvailEnv, availEnvElts, addAvail,
33 Stage(..), topStage, topSpliceStage,
34 Level, impLevel, topLevel,
37 Inst(..), InstOrigin(..), InstLoc(..), pprInstLoc, instLocSrcLoc,
38 LIE, emptyLIE, unitLIE, plusLIE, consLIE,
39 plusLIEs, mkLIE, isEmptyLIE, lieToList, listToLIE,
45 #include "HsVersions.h"
47 import HsSyn ( PendingSplice, HsOverLit, MonoBinds, RuleDecl, ForeignDecl )
48 import RnHsSyn ( RenamedHsExpr, RenamedPat, RenamedArithSeqInfo )
49 import HscTypes ( GhciMode, ExternalPackageState, HomePackageTable, NameCache,
50 GlobalRdrEnv, LocalRdrEnv, FixityEnv, TypeEnv, TyThing,
51 Avails, GenAvailInfo(..), AvailInfo, availName,
52 IsBootInterface, Deprecations )
53 import Packages ( PackageName )
54 import TcType ( TcTyVarSet, TcType, TcTauType, TcThetaType, TcPredType, TcKind,
55 tcCmpPred, tcCmpType, tcCmpTypes )
56 import InstEnv ( DFunId, InstEnv )
59 import NameSet ( NameSet, emptyNameSet )
61 import Class ( Class )
62 import Var ( Id, TyVar )
63 import VarEnv ( TidyEnv )
65 import SrcLoc ( SrcLoc )
66 import VarSet ( IdSet )
67 import ErrUtils ( Messages, Message )
68 import CmdLineOpts ( DynFlags )
69 import UniqSupply ( UniqSupply )
70 import BasicTypes ( IPName )
71 import Util ( thenCmp )
74 import DATA_IOREF ( IORef, newIORef, readIORef, writeIORef )
75 import UNSAFE_IO ( unsafeInterleaveIO )
76 import FIX_IO ( fixIO )
77 import EXCEPTION ( Exception )
78 import Maybe ( mapMaybe )
79 import ListSetOps ( unionLists )
80 import Panic ( tryMost )
85 type TcRef a = IORef a
86 type TcId = Id -- Type may be a TcType
90 %************************************************************************
92 Standard monad definition for TcRn
93 All the combinators for the monad can be found in TcRnMonad
95 %************************************************************************
97 The monad itself has to be defined here,
98 because it is mentioned by ErrCtxt
101 newtype TcRn m a = TcRn (Env m -> IO a)
104 type TcM a = TcRn TcLclEnv a
105 type RnM a = TcRn RnLclEnv a
107 returnM :: a -> TcRn m a
108 returnM a = TcRn (\ env -> return a)
110 thenM :: TcRn m a -> (a -> TcRn m b) -> TcRn m b
111 thenM (TcRn m) f = TcRn (\ env -> do { r <- m env ;
114 thenM_ :: TcRn m a -> TcRn m b -> TcRn m b
115 thenM_ (TcRn m) f = TcRn (\ env -> do { m env ; unTcRn f env })
118 failM = TcRn (\ env -> ioError (userError "TcRn failure"))
120 instance Monad (TcRn m) where
124 fail s = failM -- Ignore the string
128 %************************************************************************
130 Fundmantal combinators specific to the monad
132 %************************************************************************
137 runTcRn :: Env m -> TcRn m a -> IO a
138 runTcRn env (TcRn m) = m env
141 The fixpoint combinator
144 {-# NOINLINE fixM #-}
145 -- Aargh! Not inlining fixTc alleviates a space leak problem.
146 -- Normally fixTc is used with a lazy tuple match: if the optimiser is
147 -- shown the definition of fixTc, it occasionally transforms the code
148 -- in such a way that the code generator doesn't spot the selector
151 fixM :: (a -> TcRn m a) -> TcRn m a
152 fixM f = TcRn (\ env -> fixIO (\ r -> unTcRn (f r) env))
158 tryM :: TcRn m r -> TcRn m (Either Exception r)
159 -- Reflect exception into TcRn monad
160 tryM (TcRn thing) = TcRn (\ env -> tryMost (thing env))
166 unsafeInterleaveM :: TcRn m a -> TcRn m a
167 unsafeInterleaveM (TcRn m) = TcRn (\ env -> unsafeInterleaveIO (m env))
172 Performing arbitrary I/O, plus the read/write var (for efficiency)
175 ioToTcRn :: IO a -> TcRn m a
176 ioToTcRn io = TcRn (\ env -> io)
178 newMutVar :: a -> TcRn m (TcRef a)
179 newMutVar val = TcRn (\ env -> newIORef val)
181 writeMutVar :: TcRef a -> a -> TcRn m ()
182 writeMutVar var val = TcRn (\ env -> writeIORef var val)
184 readMutVar :: TcRef a -> TcRn m a
185 readMutVar var = TcRn (\ env -> readIORef var)
188 Getting the environment
191 getEnv :: TcRn m (Env m)
192 {-# INLINE getEnv #-}
193 getEnv = TcRn (\ env -> return env)
195 setEnv :: Env n -> TcRn n a -> TcRn m a
196 {-# INLINE setEnv #-}
197 setEnv new_env (TcRn m) = TcRn (\ env -> m new_env)
199 updEnv :: (Env m -> Env n) -> TcRn n a -> TcRn m a
200 {-# INLINE updEnv #-}
201 updEnv upd (TcRn m) = TcRn (\ env -> m (upd env))
205 %************************************************************************
207 The main environment types
209 %************************************************************************
212 data Env a -- Changes as we move into an expression
214 env_top :: TopEnv, -- Top-level stuff that never changes
215 -- Mainly a bunch of updatable refs
216 -- Includes all info about imported things
217 env_gbl :: TcGblEnv, -- Info about things defined at the top leve
218 -- of the module being compiled
220 env_lcl :: a, -- Different for the type checker
223 env_loc :: SrcLoc -- Source location
226 data TopEnv -- Built once at top level then does not change
227 -- Concerns imported stuff
228 -- Exceptions: error recovery points, meta computation points
230 top_mode :: GhciMode,
231 top_dflags :: DynFlags,
233 -- Stuff about imports
234 top_eps :: TcRef ExternalPackageState,
235 -- PIT, ImportedModuleInfo
236 -- DeclsMap, IfaceRules, IfaceInsts, InstGates
237 -- TypeEnv, InstEnv, RuleBase
238 -- Mutable, because we demand-load declarations that extend the state
240 top_hpt :: HomePackageTable,
241 -- The home package table that we've accumulated while
242 -- compiling the home package,
243 -- *excluding* the module we are compiling right now.
244 -- (In one-shot mode the current module is the only
245 -- home-package module, so tc_hpt is empty. All other
246 -- modules count as "external-package" modules.)
247 -- tc_hpt is not mutable because we only demand-load
248 -- external packages; the home package is eagerly
249 -- loaded by the compilation manager.
251 -- The global name supply
252 top_nc :: TcRef NameCache, -- Maps original names to Names
253 top_us :: TcRef UniqSupply, -- Unique supply for this module
254 top_errs :: TcRef Messages
257 -- TcGblEnv describes the top-level of the module at the
258 -- point at which the typechecker is finished work.
259 -- It is this structure that is handed on to the desugarer
263 tcg_mod :: Module, -- Module being compiled
264 tcg_usages :: TcRef EntityUsage, -- What version of what entities
265 -- have been used from other home-pkg modules
266 tcg_rdr_env :: GlobalRdrEnv, -- Top level envt; used during renaming
267 tcg_fix_env :: FixityEnv, -- Ditto
268 tcg_default :: [Type], -- Types used for defaulting
270 tcg_type_env :: TypeEnv, -- Global type env for the module we are compiling now
271 -- All TyCons and Classes (for this module) end up in here right away,
272 -- along with their derived constructors, selectors.
274 -- (Ids defined in this module start in the local envt,
275 -- though they move to the global envt during zonking)
277 tcg_inst_env :: TcRef InstEnv, -- Global instance env: a combination of
278 -- tc_pcs, tc_hpt, *and* tc_insts
279 -- This field is mutable so that it can be updated inside a
280 -- Template Haskell splice, which might suck in some new
281 -- instance declarations. This is a slightly differen strategy
282 -- than for the type envt, where we look up first in tcg_type_env
283 -- and then in the mutable EPS, because the InstEnv for this module
284 -- is constructed (in principle at least) only from the modules
285 -- 'below' this one, so it's this-module-specific
287 -- Now a bunch of things about this module that are simply
288 -- accumulated, but never consulted until the end.
289 -- Nevertheless, it's convenient to accumulate them along
290 -- with the rest of the info from this module.
291 tcg_exports :: Avails, -- What is exported
292 tcg_imports :: ImportAvails, -- Information about what was imported
293 -- from where, including things bound
295 -- The next fields are always fully zonked
296 tcg_binds :: MonoBinds Id, -- Value bindings in this module
297 tcg_deprecs :: Deprecations, -- ...Deprecations
298 tcg_insts :: [DFunId], -- ...Instances
299 tcg_rules :: [RuleDecl Id], -- ...Rules
300 tcg_fords :: [ForeignDecl Id] -- ...Foreign import & exports
305 %************************************************************************
307 The local typechecker environment
309 %************************************************************************
311 The Global-Env/Local-Env story
312 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
313 During type checking, we keep in the tcg_type_env
314 * All types and classes
315 * All Ids derived from types and classes (constructors, selectors)
317 At the end of type checking, we zonk the local bindings,
318 and as we do so we add to the tcg_type_env
319 * Locally defined top-level Ids
321 Why? Because they are now Ids not TcIds. This final GlobalEnv is
322 a) fed back (via the knot) to typechecking the
323 unfoldings of interface signatures
324 b) used in the ModDetails of this module
329 tcl_ctxt :: ErrCtxt, -- Error context
331 tcl_level :: Stage, -- Template Haskell context
333 tcl_env :: NameEnv TcTyThing, -- The local type environment: Ids and TyVars
334 -- defined in this module
336 tcl_tyvars :: TcRef TcTyVarSet, -- The "global tyvars"
337 -- Namely, the in-scope TyVars bound in tcl_lenv,
338 -- plus the tyvars mentioned in the types of
339 -- Ids bound in tcl_lenv
340 -- Why mutable? see notes with tcGetGlobalTyVars
342 tcl_lie :: TcRef LIE -- Place to accumulate type constraints
348 = Comp -- Ordinary compiling, at level topLevel
349 | Splice Level -- Inside a splice
350 | Brack Level -- Inside brackets;
351 (TcRef [PendingSplice]) -- accumulate pending splices here
352 (TcRef LIE) -- and type constraints here
353 topStage, topSpliceStage :: Stage
355 topSpliceStage = Splice (topLevel - 1) -- Stage for the body of a top-level splice
358 impLevel, topLevel :: Level
359 topLevel = 1 -- Things defined at top level of this module
360 impLevel = 0 -- Imported things; they can be used inside a top level splice
364 -- g1 = $(map ...) is OK
365 -- g2 = $(f ...) is not OK; because we havn't compiled f yet
368 = AGlobal TyThing -- Used only in the return type of a lookup
369 | ATcId TcId Level -- Ids defined in this module; may not be fully zonked
370 | ATyVar TyVar -- Type variables
371 | AThing TcKind -- Used temporarily, during kind checking
372 -- Here's an example of how the AThing guy is used
373 -- Suppose we are checking (forall a. T a Int):
374 -- 1. We first bind (a -> AThink kv), where kv is a kind variable.
375 -- 2. Then we kind-check the (T a Int) part.
376 -- 3. Then we zonk the kind variable.
377 -- 4. Now we know the kind for 'a', and we add (a -> ATyVar a::K) to the environment
379 instance Outputable TcTyThing where -- Debugging only
380 ppr (AGlobal g) = text "AGlobal" <+> ppr g
381 ppr (ATcId g l) = text "ATcId" <+> ppr g <+> ppr l
382 ppr (ATyVar t) = text "ATyVar" <+> ppr t
383 ppr (AThing k) = text "AThing" <+> ppr k
387 type ErrCtxt = [TidyEnv -> TcM (TidyEnv, Message)]
388 -- Innermost first. Monadic so that we have a chance
389 -- to deal with bound type variables just before error
390 -- message construction
394 %************************************************************************
396 The local renamer environment
398 %************************************************************************
404 rn_lenv :: LocalRdrEnv -- Local name envt
405 -- Does *not* include global name envt; may shadow it
406 -- Includes both ordinary variables and type variables;
407 -- they are kept distinct because tyvar have a different
408 -- occurrence contructor (Name.TvOcc)
409 -- We still need the unsullied global name env so that
410 -- we can look up record field names
413 data RnMode = SourceMode -- Renaming source code
414 | InterfaceMode Module -- Renaming interface declarations from M
415 | CmdLineMode -- Renaming a command-line expression
417 isInterfaceMode (InterfaceMode _) = True
418 isInterfaceMode _ = False
420 isCmdLineMode CmdLineMode = True
421 isCmdLineMode _ = False
425 %************************************************************************
429 %************************************************************************
431 EntityUsage tells what things are actually need in order to compile this
432 module. It is used for generating the usage-version field of the ModIface.
434 Note that we do not record version info for entities from
435 other (non-home) packages. If the package changes, GHC doesn't help.
438 type EntityUsage = NameSet
439 -- The Names are all the (a) home-package
440 -- (b) "big" (i.e. no data cons, class ops)
441 -- (c) non-locally-defined
443 -- names that have been slurped in so far.
444 -- This is used to generate the "usage" information for this module.
446 emptyUsages :: EntityUsage
447 emptyUsages = emptyNameSet
451 %************************************************************************
453 Operations over ImportAvails
455 %************************************************************************
457 ImportAvails summarises what was imported from where, irrespective
458 of whether the imported htings are actually used or not
459 It is used * when porcessing the export list
460 * when constructing usage info for the inteface file
461 * to identify the list of directly imported modules
462 for initialisation purposes
468 -- All the things that are available from the import
469 -- Its domain is all the "main" things;
470 -- i.e. *excluding* class ops and constructors
471 -- (which appear inside their parent AvailTC)
473 imp_qual :: ModuleEnv AvailEnv,
474 -- Used to figure out "module M" export specifiers
475 -- (see 1.4 Report Section 5.1.1). Ultimately, we want to find
476 -- everything that is unambiguously in scope as 'M.x'
477 -- and where plain 'x' is (perhaps ambiguously) in scope.
478 -- So the starting point is all things that are in scope as 'M.x',
479 -- which is what this field tells us.
481 -- Domain is the *module qualifier* for imports.
482 -- e.g. import List as Foo
483 -- would add a binding Foo |-> ...stuff from List...
485 -- We keep the stuff as an AvailEnv so that it's easy to
486 -- combine stuff coming from different (unqualified)
487 -- imports of the same module
489 imp_mods :: ModuleEnv (Module, Bool),
490 -- Domain is all directly-imported modules
491 -- Bool is True if there was an unrestricted import
492 -- (i.e. not a selective list)
493 -- We need the Module in the range because we can't get
494 -- the keys of a ModuleEnv
496 -- (a) to help construct the usage information in
497 -- the interface file; if we import everything we
498 -- need to recompile if the module version changes
499 -- (b) to specify what child modules to initialise
501 imp_dep_mods :: ModuleEnv (ModuleName, IsBootInterface),
502 -- Home-package modules needed by the module being compiled
504 -- It doesn't matter whether any of these dependencies are actually
505 -- *used* when compiling the module; they are listed if they are below
506 -- it at all. For example, suppose M imports A which imports X. Then
507 -- compiling M might not need to consult X.hi, but X is still listed
508 -- in M's dependencies.
510 imp_dep_pkgs :: [PackageName],
511 -- Packages needed by the module being compiled, whether
512 -- directly, or via other modules in this package, or via
513 -- modules imported from other packages.
515 imp_orphs :: [ModuleName]
516 -- Orphan modules below us in the import tree
519 emptyImportAvails :: ImportAvails
520 emptyImportAvails = ImportAvails { imp_env = emptyAvailEnv,
521 imp_qual = emptyModuleEnv,
522 imp_mods = emptyModuleEnv,
523 imp_dep_mods = emptyModuleEnv,
527 plusImportAvails :: ImportAvails -> ImportAvails -> ImportAvails
529 (ImportAvails { imp_env = env1, imp_qual = unqual1, imp_mods = mods1,
530 imp_dep_mods = dmods1, imp_dep_pkgs = dpkgs1, imp_orphs = orphs1 })
531 (ImportAvails { imp_env = env2, imp_qual = unqual2, imp_mods = mods2,
532 imp_dep_mods = dmods2, imp_dep_pkgs = dpkgs2, imp_orphs = orphs2 })
533 = ImportAvails { imp_env = env1 `plusAvailEnv` env2,
534 imp_qual = plusModuleEnv_C plusAvailEnv unqual1 unqual2,
535 imp_mods = mods1 `plusModuleEnv` mods2,
536 imp_dep_mods = plusModuleEnv_C plus_mod_dep dmods1 dmods2,
537 imp_dep_pkgs = dpkgs1 `unionLists` dpkgs2,
538 imp_orphs = orphs1 `unionLists` orphs2 }
540 plus_mod_dep (m1, boot1) (m2, boot2)
541 = WARN( not (m1 == m2), (ppr m1 <+> ppr m2) $$ (ppr boot1 <+> ppr boot2) )
542 -- Check mod-names match
543 (m1, boot1 && boot2) -- If either side can "see" a non-hi-boot interface, use that
546 %************************************************************************
548 Avails, AvailEnv, etc
550 v%************************************************************************
553 plusAvail (Avail n1) (Avail n2) = Avail n1
554 plusAvail (AvailTC n1 ns1) (AvailTC n2 ns2) = AvailTC n2 (ns1 `unionLists` ns2)
557 plusAvail a1 a2 = pprPanic "RnEnv.plusAvail" (hsep [ppr a1,ppr a2])
560 -------------------------
561 pruneAvails :: (Name -> Bool) -- Keep if this is True
564 pruneAvails keep avails
565 = mapMaybe del avails
567 del :: AvailInfo -> Maybe AvailInfo -- Nothing => nothing left!
568 del (Avail n) | keep n = Just (Avail n)
569 | otherwise = Nothing
570 del (AvailTC n ns) | null ns' = Nothing
571 | otherwise = Just (AvailTC n ns')
576 ---------------------------------------
578 ---------------------------------------
581 type AvailEnv = NameEnv AvailInfo -- Maps a Name to the AvailInfo that contains it
583 emptyAvailEnv :: AvailEnv
584 emptyAvailEnv = emptyNameEnv
586 unitAvailEnv :: AvailInfo -> AvailEnv
587 unitAvailEnv a = unitNameEnv (availName a) a
589 plusAvailEnv :: AvailEnv -> AvailEnv -> AvailEnv
590 plusAvailEnv = plusNameEnv_C plusAvail
592 lookupAvailEnv = lookupNameEnv
594 availEnvElts = nameEnvElts
596 addAvail :: AvailEnv -> AvailInfo -> AvailEnv
597 addAvail avails avail = extendNameEnv_C plusAvail avails (availName avail) avail
599 mkAvailEnv :: [AvailInfo] -> AvailEnv
600 -- 'avails' may have several items with the same availName
601 -- E.g import Ix( Ix(..), index )
602 -- will give Ix(Ix,index,range) and Ix(index)
603 -- We want to combine these; addAvail does that
604 mkAvailEnv avails = foldl addAvail emptyAvailEnv avails
607 %************************************************************************
609 \subsection{Where from}
611 %************************************************************************
613 The @WhereFrom@ type controls where the renamer looks for an interface file
617 = ImportByUser IsBootInterface -- Ordinary user import (perhaps {-# SOURCE #-})
619 | ImportForUsage IsBootInterface -- Import when chasing usage info from an interaface file
620 -- Failure in this case is not an error
622 | ImportBySystem -- Non user import.
624 instance Outputable WhereFrom where
625 ppr (ImportByUser is_boot) | is_boot = ptext SLIT("{- SOURCE -}")
627 ppr (ImportForUsage is_boot) | is_boot = ptext SLIT("{- USAGE SOURCE -}")
628 | otherwise = ptext SLIT("{- USAGE -}")
629 ppr ImportBySystem = ptext SLIT("{- SYSTEM -}")
633 %************************************************************************
635 \subsection[Inst-types]{@Inst@ types}
637 v%************************************************************************
639 An @Inst@ is either a dictionary, an instance of an overloaded
640 literal, or an instance of an overloaded value. We call the latter a
641 ``method'' even though it may not correspond to a class operation.
642 For example, we might have an instance of the @double@ function at
643 type Int, represented by
645 Method 34 doubleId [Int] origin
657 TcId -- The overloaded function
658 -- This function will be a global, local, or ClassOpId;
659 -- inside instance decls (only) it can also be an InstId!
660 -- The id needn't be completely polymorphic.
661 -- You'll probably find its name (for documentation purposes)
662 -- inside the InstOrigin
664 [TcType] -- The types to which its polymorphic tyvars
665 -- should be instantiated.
666 -- These types must saturate the Id's foralls.
668 TcThetaType -- The (types of the) dictionaries to which the function
669 -- must be applied to get the method
671 TcTauType -- The tau-type of the method
675 -- INVARIANT 1: in (Method u f tys theta tau loc)
676 -- type of (f tys dicts(from theta)) = tau
678 -- INVARIANT 2: tau must not be of form (Pred -> Tau)
679 -- Reason: two methods are considerd equal if the
680 -- base Id matches, and the instantiating types
681 -- match. The TcThetaType should then match too.
682 -- This only bites in the call to tcInstClassOp in TcClassDcl.mkMethodBind
686 HsOverLit -- The literal from the occurrence site
687 -- INVARIANT: never a rebindable-syntax literal
688 -- Reason: tcSyntaxName does unification, and we
689 -- don't want to deal with that during tcSimplify
690 TcType -- The type at which the literal is used
694 @Insts@ are ordered by their class/type info, rather than by their
695 unique. This allows the context-reduction mechanism to use standard finite
696 maps to do their stuff.
699 instance Ord Inst where
702 instance Eq Inst where
703 (==) i1 i2 = case i1 `cmpInst` i2 of
707 cmpInst (Dict _ pred1 _) (Dict _ pred2 _) = pred1 `tcCmpPred` pred2
708 cmpInst (Dict _ _ _) other = LT
710 cmpInst (Method _ _ _ _ _ _) (Dict _ _ _) = GT
711 cmpInst (Method _ id1 tys1 _ _ _) (Method _ id2 tys2 _ _ _) = (id1 `compare` id2) `thenCmp` (tys1 `tcCmpTypes` tys2)
712 cmpInst (Method _ _ _ _ _ _) other = LT
714 cmpInst (LitInst _ _ _ _) (Dict _ _ _) = GT
715 cmpInst (LitInst _ _ _ _) (Method _ _ _ _ _ _) = GT
716 cmpInst (LitInst _ lit1 ty1 _) (LitInst _ lit2 ty2 _) = (lit1 `compare` lit2) `thenCmp` (ty1 `tcCmpType` ty2)
720 %************************************************************************
722 \subsection[Inst-collections]{LIE: a collection of Insts}
724 %************************************************************************
729 isEmptyLIE = isEmptyBag
731 unitLIE inst = unitBag inst
732 mkLIE insts = listToBag insts
733 plusLIE lie1 lie2 = lie1 `unionBags` lie2
734 consLIE inst lie = inst `consBag` lie
735 plusLIEs lies = unionManyBags lies
736 lieToList = bagToList
737 listToLIE = listToBag
741 %************************************************************************
743 \subsection[Inst-origin]{The @InstOrigin@ type}
745 %************************************************************************
747 The @InstOrigin@ type gives information about where a dictionary came from.
748 This is important for decent error message reporting because dictionaries
749 don't appear in the original source code. Doubtless this type will evolve...
751 It appears in TcMonad because there are a couple of error-message-generation
752 functions that deal with it.
755 data InstLoc = InstLoc InstOrigin SrcLoc ErrCtxt
757 instLocSrcLoc :: InstLoc -> SrcLoc
758 instLocSrcLoc (InstLoc _ src_loc _) = src_loc
761 = OccurrenceOf Name -- Occurrence of an overloaded identifier
763 | IPOcc (IPName Name) -- Occurrence of an implicit parameter
764 | IPBind (IPName Name) -- Binding site of an implicit parameter
768 | DataDeclOrigin -- Typechecking a data declaration
770 | InstanceDeclOrigin -- Typechecking an instance decl
772 | LiteralOrigin HsOverLit -- Occurrence of a literal
774 | PatOrigin RenamedPat
776 | ArithSeqOrigin RenamedArithSeqInfo -- [x..], [x..y] etc
777 | PArrSeqOrigin RenamedArithSeqInfo -- [:x..y:] and [:x,y..z:]
779 | SignatureOrigin -- A dict created from a type signature
780 | Rank2Origin -- A dict created when typechecking the argument
781 -- of a rank-2 typed function
783 | DoOrigin -- The monad for a do expression
785 | ClassDeclOrigin -- Manufactured during a class decl
787 | InstanceSpecOrigin Class -- in a SPECIALIZE instance pragma
790 -- When specialising instances the instance info attached to
791 -- each class is not yet ready, so we record it inside the
792 -- origin information. This is a bit of a hack, but it works
793 -- fine. (Patrick is to blame [WDP].)
795 | ValSpecOrigin Name -- in a SPECIALIZE pragma for a value
797 -- Argument or result of a ccall
798 -- Dictionaries with this origin aren't actually mentioned in the
799 -- translated term, and so need not be bound. Nor should they
800 -- be abstracted over.
802 | CCallOrigin String -- CCall label
803 (Maybe RenamedHsExpr) -- Nothing if it's the result
804 -- Just arg, for an argument
806 | LitLitOrigin String -- the litlit
808 | UnknownOrigin -- Help! I give up...
812 pprInstLoc :: InstLoc -> SDoc
813 pprInstLoc (InstLoc orig locn ctxt)
814 = hsep [text "arising from", pp_orig orig, text "at", ppr locn]
816 pp_orig (OccurrenceOf name)
817 = hsep [ptext SLIT("use of"), quotes (ppr name)]
819 = hsep [ptext SLIT("use of implicit parameter"), quotes (ppr name)]
820 pp_orig (IPBind name)
821 = hsep [ptext SLIT("binding for implicit parameter"), quotes (ppr name)]
822 pp_orig RecordUpdOrigin
823 = ptext SLIT("a record update")
824 pp_orig DataDeclOrigin
825 = ptext SLIT("the data type declaration")
826 pp_orig InstanceDeclOrigin
827 = ptext SLIT("the instance declaration")
828 pp_orig (LiteralOrigin lit)
829 = hsep [ptext SLIT("the literal"), quotes (ppr lit)]
830 pp_orig (PatOrigin pat)
831 = hsep [ptext SLIT("the pattern"), quotes (ppr pat)]
832 pp_orig (ArithSeqOrigin seq)
833 = hsep [ptext SLIT("the arithmetic sequence"), quotes (ppr seq)]
834 pp_orig (PArrSeqOrigin seq)
835 = hsep [ptext SLIT("the parallel array sequence"), quotes (ppr seq)]
836 pp_orig (SignatureOrigin)
837 = ptext SLIT("a type signature")
838 pp_orig (Rank2Origin)
839 = ptext SLIT("a function with an overloaded argument type")
841 = ptext SLIT("a do statement")
842 pp_orig (ClassDeclOrigin)
843 = ptext SLIT("a class declaration")
844 pp_orig (InstanceSpecOrigin clas ty)
845 = hsep [text "a SPECIALIZE instance pragma; class",
846 quotes (ppr clas), text "type:", ppr ty]
847 pp_orig (ValSpecOrigin name)
848 = hsep [ptext SLIT("a SPECIALIZE user-pragma for"), quotes (ppr name)]
849 pp_orig (CCallOrigin clabel Nothing{-ccall result-})
850 = hsep [ptext SLIT("the result of the _ccall_ to"), quotes (text clabel)]
851 pp_orig (CCallOrigin clabel (Just arg_expr))
852 = hsep [ptext SLIT("an argument in the _ccall_ to"), quotes (text clabel) <> comma,
853 text "namely", quotes (ppr arg_expr)]
854 pp_orig (LitLitOrigin s)
855 = hsep [ptext SLIT("the ``literal-literal''"), quotes (text s)]
856 pp_orig (UnknownOrigin)
857 = ptext SLIT("...oops -- I don't know where the overloading came from!")