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
239 top_hpt :: HomePackageTable,
240 -- The home package table that we've accumulated while
241 -- compiling the home package,
242 -- *excluding* the module we are compiling right now.
243 -- (In one-shot mode the current module is the only
244 -- home-package module, so tc_hpt is empty. All other
245 -- modules count as "external-package" modules.)
246 -- tc_hpt is not mutable because we only demand-load
247 -- external packages; the home package is eagerly
248 -- loaded by the compilation manager.
250 -- The global name supply
251 top_nc :: TcRef NameCache, -- Maps original names to Names
252 top_us :: TcRef UniqSupply, -- Unique supply for this module
253 top_errs :: TcRef Messages
256 -- TcGblEnv describes the top-level of the module at the
257 -- point at which the typechecker is finished work.
258 -- It is this structure that is handed on to the desugarer
262 tcg_mod :: Module, -- Module being compiled
263 tcg_usages :: TcRef EntityUsage, -- What version of what entities
264 -- have been used from other home-pkg modules
265 tcg_rdr_env :: GlobalRdrEnv, -- Top level envt; used during renaming
266 tcg_fix_env :: FixityEnv, -- Ditto
267 tcg_default :: [Type], -- Types used for defaulting
269 tcg_type_env :: TypeEnv, -- Global type env for the module we are compiling now
270 -- All TyCons and Classes (for this module) end up in here right away,
271 -- along with their derived constructors, selectors.
273 -- (Ids defined in this module start in the local envt,
274 -- though they move to the global envt during zonking)
277 tcg_ist :: Name -> Maybe TyThing, -- Imported symbol table
278 -- Global type env: a combination of tcg_eps, tcg_hpt
279 -- (but *not* tcg_type_env; no deep reason)
280 -- When the PCS changes this must be refreshed,
281 -- notably after running some compile-time code
283 tcg_inst_env :: InstEnv, -- Global instance env: a combination of
284 -- tc_pcs, tc_hpt, *and* tc_insts
286 -- Now a bunch of things about this module that are simply
287 -- accumulated, but never consulted until the end.
288 -- Nevertheless, it's convenient to accumulate them along
289 -- with the rest of the info from this module.
290 tcg_exports :: Avails, -- What is exported
291 tcg_imports :: ImportAvails, -- Information about what was imported
292 -- from where, including things bound
294 -- The next fields are always fully zonked
295 tcg_binds :: MonoBinds Id, -- Value bindings in this module
296 tcg_deprecs :: Deprecations, -- ...Deprecations
297 tcg_insts :: [DFunId], -- ...Instances
298 tcg_rules :: [RuleDecl Id], -- ...Rules
299 tcg_fords :: [ForeignDecl Id] -- ...Foreign import & exports
304 %************************************************************************
306 The local typechecker environment
308 %************************************************************************
310 The Global-Env/Local-Env story
311 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
312 During type checking, we keep in the tcg_type_env
313 * All types and classes
314 * All Ids derived from types and classes (constructors, selectors)
316 At the end of type checking, we zonk the local bindings,
317 and as we do so we add to the tcg_type_env
318 * Locally defined top-level Ids
320 Why? Because they are now Ids not TcIds. This final GlobalEnv is
321 a) fed back (via the knot) to typechecking the
322 unfoldings of interface signatures
323 b) used in the ModDetails of this module
328 tcl_ctxt :: ErrCtxt, -- Error context
330 tcl_level :: Stage, -- Template Haskell context
332 tcl_env :: NameEnv TcTyThing, -- The local type environment: Ids and TyVars
333 -- defined in this module
335 tcl_tyvars :: TcRef TcTyVarSet, -- The "global tyvars"
336 -- Namely, the in-scope TyVars bound in tcl_lenv,
337 -- plus the tyvars mentioned in the types of
338 -- Ids bound in tcl_lenv
339 -- Why mutable? see notes with tcGetGlobalTyVars
341 tcl_lie :: TcRef LIE -- Place to accumulate type constraints
347 = Comp -- Ordinary compiling, at level topLevel
348 | Splice Level -- Inside a splice
349 | Brack Level -- Inside brackets;
350 (TcRef [PendingSplice]) -- accumulate pending splices here
351 (TcRef LIE) -- and type constraints here
352 topStage, topSpliceStage :: Stage
354 topSpliceStage = Splice (topLevel - 1) -- Stage for the body of a top-level splice
357 impLevel, topLevel :: Level
358 topLevel = 1 -- Things dedined at top level of this module
359 impLevel = 0 -- Imported things; they can be used inside a top level splice
363 -- g1 = $(map ...) is OK
364 -- g2 = $(f ...) is not OK; because we havn't compiled f yet
367 = AGlobal TyThing -- Used only in the return type of a lookup
368 | ATcId TcId Level -- Ids defined in this module; may not be fully zonked
369 | ATyVar TyVar -- Type variables
370 | AThing TcKind -- Used temporarily, during kind checking
371 -- Here's an example of how the AThing guy is used
372 -- Suppose we are checking (forall a. T a Int):
373 -- 1. We first bind (a -> AThink kv), where kv is a kind variable.
374 -- 2. Then we kind-check the (T a Int) part.
375 -- 3. Then we zonk the kind variable.
376 -- 4. Now we know the kind for 'a', and we add (a -> ATyVar a::K) to the environment
378 instance Outputable TcTyThing where -- Debugging only
379 ppr (AGlobal g) = text "AGlobal" <+> ppr g
380 ppr (ATcId g l) = text "ATcId" <+> ppr g <+> ppr l
381 ppr (ATyVar t) = text "ATyVar" <+> ppr t
382 ppr (AThing k) = text "AThing" <+> ppr k
386 type ErrCtxt = [TidyEnv -> TcM (TidyEnv, Message)]
387 -- Innermost first. Monadic so that we have a chance
388 -- to deal with bound type variables just before error
389 -- message construction
393 %************************************************************************
395 The local renamer environment
397 %************************************************************************
403 rn_lenv :: LocalRdrEnv -- Local name envt
404 -- Does *not* include global name envt; may shadow it
405 -- Includes both ordinary variables and type variables;
406 -- they are kept distinct because tyvar have a different
407 -- occurrence contructor (Name.TvOcc)
408 -- We still need the unsullied global name env so that
409 -- we can look up record field names
412 data RnMode = SourceMode -- Renaming source code
413 | InterfaceMode Module -- Renaming interface declarations from M
414 | CmdLineMode -- Renaming a command-line expression
416 isInterfaceMode (InterfaceMode _) = True
417 isInterfaceMode _ = False
419 isCmdLineMode CmdLineMode = True
420 isCmdLineMode _ = False
424 %************************************************************************
428 %************************************************************************
430 EntityUsage tells what things are actually need in order to compile this
431 module. It is used for generating the usage-version field of the ModIface.
433 Note that we do not record version info for entities from
434 other (non-home) packages. If the package changes, GHC doesn't help.
437 type EntityUsage = NameSet
438 -- The Names are all the (a) home-package
439 -- (b) "big" (i.e. no data cons, class ops)
440 -- (c) non-locally-defined
442 -- names that have been slurped in so far.
443 -- This is used to generate the "usage" information for this module.
445 emptyUsages :: EntityUsage
446 emptyUsages = emptyNameSet
450 %************************************************************************
452 Operations over ImportAvails
454 %************************************************************************
456 ImportAvails summarises what was imported from where, irrespective
457 of whether the imported htings are actually used or not
458 It is used * when porcessing the export list
459 * when constructing usage info for the inteface file
460 * to identify the list of directly imported modules
461 for initialisation purposes
467 -- All the things that are available from the import
468 -- Its domain is all the "main" things;
469 -- i.e. *excluding* class ops and constructors
470 -- (which appear inside their parent AvailTC)
472 imp_qual :: ModuleEnv AvailEnv,
473 -- Used to figure out "module M" export specifiers
474 -- (see 1.4 Report Section 5.1.1). Ultimately, we want to find
475 -- everything that is unambiguously in scope as 'M.x'
476 -- and where plain 'x' is (perhaps ambiguously) in scope.
477 -- So the starting point is all things that are in scope as 'M.x',
478 -- which is what this field tells us.
480 -- Domain is the *module qualifier* for imports.
481 -- e.g. import List as Foo
482 -- would add a binding Foo |-> ...stuff from List...
484 -- We keep the stuff as an AvailEnv so that it's easy to
485 -- combine stuff coming from different (unqualified)
486 -- imports of the same module
488 imp_mods :: ModuleEnv (Module, Bool),
489 -- Domain is all directly-imported modules
490 -- Bool is True if there was an unrestricted import
491 -- (i.e. not a selective list)
492 -- We need the Module in the range because we can't get
493 -- the keys of a ModuleEnv
495 -- (a) to help construct the usage information in
496 -- the interface file; if we import everything we
497 -- need to recompile if the module version changes
498 -- (b) to specify what child modules to initialise
500 imp_dep_mods :: ModuleEnv (ModuleName, IsBootInterface),
501 -- Home-package modules needed by the module being compiled
503 -- It doesn't matter whether any of these dependencies are actually
504 -- *used* when compiling the module; they are listed if they are below
505 -- it at all. For example, suppose M imports A which imports X. Then
506 -- compiling M might not need to consult X.hi, but X is still listed
507 -- in M's dependencies.
509 imp_dep_pkgs :: [PackageName],
510 -- Packages needed by the module being compiled, whether
511 -- directly, or via other modules in this package, or via
512 -- modules imported from other packages.
514 imp_orphs :: [ModuleName]
515 -- Orphan modules below us in the import tree
518 emptyImportAvails :: ImportAvails
519 emptyImportAvails = ImportAvails { imp_env = emptyAvailEnv,
520 imp_qual = emptyModuleEnv,
521 imp_mods = emptyModuleEnv,
522 imp_dep_mods = emptyModuleEnv,
526 plusImportAvails :: ImportAvails -> ImportAvails -> ImportAvails
528 (ImportAvails { imp_env = env1, imp_qual = unqual1, imp_mods = mods1,
529 imp_dep_mods = dmods1, imp_dep_pkgs = dpkgs1, imp_orphs = orphs1 })
530 (ImportAvails { imp_env = env2, imp_qual = unqual2, imp_mods = mods2,
531 imp_dep_mods = dmods2, imp_dep_pkgs = dpkgs2, imp_orphs = orphs2 })
532 = ImportAvails { imp_env = env1 `plusAvailEnv` env2,
533 imp_qual = plusModuleEnv_C plusAvailEnv unqual1 unqual2,
534 imp_mods = mods1 `plusModuleEnv` mods2,
535 imp_dep_mods = plusModuleEnv_C plus_mod_dep dmods1 dmods2,
536 imp_dep_pkgs = dpkgs1 `unionLists` dpkgs2,
537 imp_orphs = orphs1 `unionLists` orphs2 }
539 plus_mod_dep (m1, boot1) (m2, boot2)
540 = WARN( not (m1 == m2), (ppr m1 <+> ppr m2) $$ (ppr boot1 <+> ppr boot2) )
541 -- Check mod-names match
542 (m1, boot1 && boot2) -- If either side can "see" a non-hi-boot interface, use that
545 %************************************************************************
547 Avails, AvailEnv, etc
549 v%************************************************************************
552 plusAvail (Avail n1) (Avail n2) = Avail n1
553 plusAvail (AvailTC n1 ns1) (AvailTC n2 ns2) = AvailTC n2 (ns1 `unionLists` ns2)
556 plusAvail a1 a2 = pprPanic "RnEnv.plusAvail" (hsep [ppr a1,ppr a2])
559 -------------------------
560 pruneAvails :: (Name -> Bool) -- Keep if this is True
563 pruneAvails keep avails
564 = mapMaybe del avails
566 del :: AvailInfo -> Maybe AvailInfo -- Nothing => nothing left!
567 del (Avail n) | keep n = Just (Avail n)
568 | otherwise = Nothing
569 del (AvailTC n ns) | null ns' = Nothing
570 | otherwise = Just (AvailTC n ns')
575 ---------------------------------------
577 ---------------------------------------
580 type AvailEnv = NameEnv AvailInfo -- Maps a Name to the AvailInfo that contains it
582 emptyAvailEnv :: AvailEnv
583 emptyAvailEnv = emptyNameEnv
585 unitAvailEnv :: AvailInfo -> AvailEnv
586 unitAvailEnv a = unitNameEnv (availName a) a
588 plusAvailEnv :: AvailEnv -> AvailEnv -> AvailEnv
589 plusAvailEnv = plusNameEnv_C plusAvail
591 lookupAvailEnv = lookupNameEnv
593 availEnvElts = nameEnvElts
595 addAvail :: AvailEnv -> AvailInfo -> AvailEnv
596 addAvail avails avail = extendNameEnv_C plusAvail avails (availName avail) avail
598 mkAvailEnv :: [AvailInfo] -> AvailEnv
599 -- 'avails' may have several items with the same availName
600 -- E.g import Ix( Ix(..), index )
601 -- will give Ix(Ix,index,range) and Ix(index)
602 -- We want to combine these; addAvail does that
603 mkAvailEnv avails = foldl addAvail emptyAvailEnv avails
606 %************************************************************************
608 \subsection{Where from}
610 %************************************************************************
612 The @WhereFrom@ type controls where the renamer looks for an interface file
616 = ImportByUser IsBootInterface -- Ordinary user import (perhaps {-# SOURCE #-})
618 | ImportForUsage IsBootInterface -- Import when chasing usage info from an interaface file
619 -- Failure in this case is not an error
621 | ImportBySystem -- Non user import.
623 instance Outputable WhereFrom where
624 ppr (ImportByUser is_boot) | is_boot = ptext SLIT("{- SOURCE -}")
626 ppr (ImportForUsage is_boot) | is_boot = ptext SLIT("{- USAGE SOURCE -}")
627 | otherwise = ptext SLIT("{- USAGE -}")
628 ppr ImportBySystem = ptext SLIT("{- SYSTEM -}")
632 %************************************************************************
634 \subsection[Inst-types]{@Inst@ types}
636 v%************************************************************************
638 An @Inst@ is either a dictionary, an instance of an overloaded
639 literal, or an instance of an overloaded value. We call the latter a
640 ``method'' even though it may not correspond to a class operation.
641 For example, we might have an instance of the @double@ function at
642 type Int, represented by
644 Method 34 doubleId [Int] origin
656 TcId -- The overloaded function
657 -- This function will be a global, local, or ClassOpId;
658 -- inside instance decls (only) it can also be an InstId!
659 -- The id needn't be completely polymorphic.
660 -- You'll probably find its name (for documentation purposes)
661 -- inside the InstOrigin
663 [TcType] -- The types to which its polymorphic tyvars
664 -- should be instantiated.
665 -- These types must saturate the Id's foralls.
667 TcThetaType -- The (types of the) dictionaries to which the function
668 -- must be applied to get the method
670 TcTauType -- The type of the method
674 -- INVARIANT: in (Method u f tys theta tau loc)
675 -- type of (f tys dicts(from theta)) = tau
679 HsOverLit -- The literal from the occurrence site
680 -- INVARIANT: never a rebindable-syntax literal
681 -- Reason: tcSyntaxName does unification, and we
682 -- don't want to deal with that during tcSimplify
683 TcType -- The type at which the literal is used
687 @Insts@ are ordered by their class/type info, rather than by their
688 unique. This allows the context-reduction mechanism to use standard finite
689 maps to do their stuff.
692 instance Ord Inst where
695 instance Eq Inst where
696 (==) i1 i2 = case i1 `cmpInst` i2 of
700 cmpInst (Dict _ pred1 _) (Dict _ pred2 _) = pred1 `tcCmpPred` pred2
701 cmpInst (Dict _ _ _) other = LT
703 cmpInst (Method _ _ _ _ _ _) (Dict _ _ _) = GT
704 cmpInst (Method _ id1 tys1 _ _ _) (Method _ id2 tys2 _ _ _) = (id1 `compare` id2) `thenCmp` (tys1 `tcCmpTypes` tys2)
705 cmpInst (Method _ _ _ _ _ _) other = LT
707 cmpInst (LitInst _ _ _ _) (Dict _ _ _) = GT
708 cmpInst (LitInst _ _ _ _) (Method _ _ _ _ _ _) = GT
709 cmpInst (LitInst _ lit1 ty1 _) (LitInst _ lit2 ty2 _) = (lit1 `compare` lit2) `thenCmp` (ty1 `tcCmpType` ty2)
713 %************************************************************************
715 \subsection[Inst-collections]{LIE: a collection of Insts}
717 %************************************************************************
722 isEmptyLIE = isEmptyBag
724 unitLIE inst = unitBag inst
725 mkLIE insts = listToBag insts
726 plusLIE lie1 lie2 = lie1 `unionBags` lie2
727 consLIE inst lie = inst `consBag` lie
728 plusLIEs lies = unionManyBags lies
729 lieToList = bagToList
730 listToLIE = listToBag
734 %************************************************************************
736 \subsection[Inst-origin]{The @InstOrigin@ type}
738 %************************************************************************
740 The @InstOrigin@ type gives information about where a dictionary came from.
741 This is important for decent error message reporting because dictionaries
742 don't appear in the original source code. Doubtless this type will evolve...
744 It appears in TcMonad because there are a couple of error-message-generation
745 functions that deal with it.
748 data InstLoc = InstLoc InstOrigin SrcLoc ErrCtxt
750 instLocSrcLoc :: InstLoc -> SrcLoc
751 instLocSrcLoc (InstLoc _ src_loc _) = src_loc
754 = OccurrenceOf Name -- Occurrence of an overloaded identifier
756 | IPOcc (IPName Name) -- Occurrence of an implicit parameter
757 | IPBind (IPName Name) -- Binding site of an implicit parameter
761 | DataDeclOrigin -- Typechecking a data declaration
763 | InstanceDeclOrigin -- Typechecking an instance decl
765 | LiteralOrigin HsOverLit -- Occurrence of a literal
767 | PatOrigin RenamedPat
769 | ArithSeqOrigin RenamedArithSeqInfo -- [x..], [x..y] etc
770 | PArrSeqOrigin RenamedArithSeqInfo -- [:x..y:] and [:x,y..z:]
772 | SignatureOrigin -- A dict created from a type signature
773 | Rank2Origin -- A dict created when typechecking the argument
774 -- of a rank-2 typed function
776 | DoOrigin -- The monad for a do expression
778 | ClassDeclOrigin -- Manufactured during a class decl
780 | InstanceSpecOrigin Class -- in a SPECIALIZE instance pragma
783 -- When specialising instances the instance info attached to
784 -- each class is not yet ready, so we record it inside the
785 -- origin information. This is a bit of a hack, but it works
786 -- fine. (Patrick is to blame [WDP].)
788 | ValSpecOrigin Name -- in a SPECIALIZE pragma for a value
790 -- Argument or result of a ccall
791 -- Dictionaries with this origin aren't actually mentioned in the
792 -- translated term, and so need not be bound. Nor should they
793 -- be abstracted over.
795 | CCallOrigin String -- CCall label
796 (Maybe RenamedHsExpr) -- Nothing if it's the result
797 -- Just arg, for an argument
799 | LitLitOrigin String -- the litlit
801 | UnknownOrigin -- Help! I give up...
805 pprInstLoc :: InstLoc -> SDoc
806 pprInstLoc (InstLoc orig locn ctxt)
807 = hsep [text "arising from", pp_orig orig, text "at", ppr locn]
809 pp_orig (OccurrenceOf name)
810 = hsep [ptext SLIT("use of"), quotes (ppr name)]
812 = hsep [ptext SLIT("use of implicit parameter"), quotes (ppr name)]
813 pp_orig (IPBind name)
814 = hsep [ptext SLIT("binding for implicit parameter"), quotes (ppr name)]
815 pp_orig RecordUpdOrigin
816 = ptext SLIT("a record update")
817 pp_orig DataDeclOrigin
818 = ptext SLIT("the data type declaration")
819 pp_orig InstanceDeclOrigin
820 = ptext SLIT("the instance declaration")
821 pp_orig (LiteralOrigin lit)
822 = hsep [ptext SLIT("the literal"), quotes (ppr lit)]
823 pp_orig (PatOrigin pat)
824 = hsep [ptext SLIT("the pattern"), quotes (ppr pat)]
825 pp_orig (ArithSeqOrigin seq)
826 = hsep [ptext SLIT("the arithmetic sequence"), quotes (ppr seq)]
827 pp_orig (PArrSeqOrigin seq)
828 = hsep [ptext SLIT("the parallel array sequence"), quotes (ppr seq)]
829 pp_orig (SignatureOrigin)
830 = ptext SLIT("a type signature")
831 pp_orig (Rank2Origin)
832 = ptext SLIT("a function with an overloaded argument type")
834 = ptext SLIT("a do statement")
835 pp_orig (ClassDeclOrigin)
836 = ptext SLIT("a class declaration")
837 pp_orig (InstanceSpecOrigin clas ty)
838 = hsep [text "a SPECIALIZE instance pragma; class",
839 quotes (ppr clas), text "type:", ppr ty]
840 pp_orig (ValSpecOrigin name)
841 = hsep [ptext SLIT("a SPECIALIZE user-pragma for"), quotes (ppr name)]
842 pp_orig (CCallOrigin clabel Nothing{-ccall result-})
843 = hsep [ptext SLIT("the result of the _ccall_ to"), quotes (text clabel)]
844 pp_orig (CCallOrigin clabel (Just arg_expr))
845 = hsep [ptext SLIT("an argument in the _ccall_ to"), quotes (text clabel) <> comma,
846 text "namely", quotes (ppr arg_expr)]
847 pp_orig (LitLitOrigin s)
848 = hsep [ptext SLIT("the ``literal-literal''"), quotes (text s)]
849 pp_orig (UnknownOrigin)
850 = ptext SLIT("...oops -- I don't know where the overloading came from!")