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,
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
380 type ErrCtxt = [TidyEnv -> TcM (TidyEnv, Message)]
381 -- Innermost first. Monadic so that we have a chance
382 -- to deal with bound type variables just before error
383 -- message construction
387 %************************************************************************
389 The local renamer environment
391 %************************************************************************
397 rn_lenv :: LocalRdrEnv -- Local name envt
398 -- Does *not* include global name envt; may shadow it
399 -- Includes both ordinary variables and type variables;
400 -- they are kept distinct because tyvar have a different
401 -- occurrence contructor (Name.TvOcc)
402 -- We still need the unsullied global name env so that
403 -- we can look up record field names
406 data RnMode = SourceMode -- Renaming source code
407 | InterfaceMode Module -- Renaming interface declarations from M
408 | CmdLineMode -- Renaming a command-line expression
410 isInterfaceMode (InterfaceMode _) = True
411 isInterfaceMode _ = False
413 isCmdLineMode CmdLineMode = True
414 isCmdLineMode _ = False
418 %************************************************************************
422 %************************************************************************
424 EntityUsage tells what things are actually need in order to compile this
425 module. It is used for generating the usage-version field of the ModIface.
427 Note that we do not record version info for entities from
428 other (non-home) packages. If the package changes, GHC doesn't help.
431 type EntityUsage = NameSet
432 -- The Names are all the (a) home-package
433 -- (b) "big" (i.e. no data cons, class ops)
434 -- (c) non-locally-defined
436 -- names that have been slurped in so far.
437 -- This is used to generate the "usage" information for this module.
439 emptyUsages :: EntityUsage
440 emptyUsages = emptyNameSet
444 %************************************************************************
446 Operations over ImportAvails
448 %************************************************************************
450 ImportAvails summarises what was imported from where, irrespective
451 of whether the imported htings are actually used or not
452 It is used * when porcessing the export list
453 * when constructing usage info for the inteface file
454 * to identify the list of directly imported modules
455 for initialisation purposes
461 -- All the things that are available from the import
462 -- Its domain is all the "main" things;
463 -- i.e. *excluding* class ops and constructors
464 -- (which appear inside their parent AvailTC)
466 imp_qual :: ModuleEnv AvailEnv,
467 -- Used to figure out "module M" export specifiers
468 -- (see 1.4 Report Section 5.1.1). Ultimately, we want to find
469 -- everything that is unambiguously in scope as 'M.x'
470 -- and where plain 'x' is (perhaps ambiguously) in scope.
471 -- So the starting point is all things that are in scope as 'M.x',
472 -- which is what this field tells us.
474 -- Domain is the *module qualifier* for imports.
475 -- e.g. import List as Foo
476 -- would add a binding Foo |-> ...stuff from List...
478 -- We keep the stuff as an AvailEnv so that it's easy to
479 -- combine stuff coming from different (unqualified)
480 -- imports of the same module
482 imp_mods :: ModuleEnv (Module, Bool),
483 -- Domain is all directly-imported modules
484 -- Bool is True if there was an unrestricted import
485 -- (i.e. not a selective list)
486 -- We need the Module in the range because we can't get
487 -- the keys of a ModuleEnv
489 -- (a) to help construct the usage information in
490 -- the interface file; if we import everything we
491 -- need to recompile if the module version changes
492 -- (b) to specify what child modules to initialise
494 imp_dep_mods :: ModuleEnv (ModuleName, IsBootInterface),
495 -- Home-package modules needed by the module being compiled
497 -- It doesn't matter whether any of these dependencies are actually
498 -- *used* when compiling the module; they are listed if they are below
499 -- it at all. For example, suppose M imports A which imports X. Then
500 -- compiling M might not need to consult X.hi, but X is still listed
501 -- in M's dependencies.
503 imp_dep_pkgs :: [PackageName],
504 -- Packages needed by the module being compiled, whether
505 -- directly, or via other modules in this package, or via
506 -- modules imported from other packages.
508 imp_orphs :: [ModuleName]
509 -- Orphan modules below us in the import tree
512 emptyImportAvails :: ImportAvails
513 emptyImportAvails = ImportAvails { imp_env = emptyAvailEnv,
514 imp_qual = emptyModuleEnv,
515 imp_mods = emptyModuleEnv,
516 imp_dep_mods = emptyModuleEnv,
520 plusImportAvails :: ImportAvails -> ImportAvails -> ImportAvails
522 (ImportAvails { imp_env = env1, imp_qual = unqual1, imp_mods = mods1,
523 imp_dep_mods = dmods1, imp_dep_pkgs = dpkgs1, imp_orphs = orphs1 })
524 (ImportAvails { imp_env = env2, imp_qual = unqual2, imp_mods = mods2,
525 imp_dep_mods = dmods2, imp_dep_pkgs = dpkgs2, imp_orphs = orphs2 })
526 = ImportAvails { imp_env = env1 `plusAvailEnv` env2,
527 imp_qual = plusModuleEnv_C plusAvailEnv unqual1 unqual2,
528 imp_mods = mods1 `plusModuleEnv` mods2,
529 imp_dep_mods = plusModuleEnv_C plus_mod_dep dmods1 dmods2,
530 imp_dep_pkgs = dpkgs1 `unionLists` dpkgs2,
531 imp_orphs = orphs1 `unionLists` orphs2 }
533 plus_mod_dep (m1, boot1) (m2, boot2)
534 = WARN( not (m1 == m2), (ppr m1 <+> ppr m2) $$ (ppr boot1 <+> ppr boot2) )
535 -- Check mod-names match
536 (m1, boot1 && boot2) -- If either side can "see" a non-hi-boot interface, use that
539 %************************************************************************
541 Avails, AvailEnv, etc
543 v%************************************************************************
546 plusAvail (Avail n1) (Avail n2) = Avail n1
547 plusAvail (AvailTC n1 ns1) (AvailTC n2 ns2) = AvailTC n2 (ns1 `unionLists` ns2)
550 plusAvail a1 a2 = pprPanic "RnEnv.plusAvail" (hsep [ppr a1,ppr a2])
553 -------------------------
554 pruneAvails :: (Name -> Bool) -- Keep if this is True
557 pruneAvails keep avails
558 = mapMaybe del avails
560 del :: AvailInfo -> Maybe AvailInfo -- Nothing => nothing left!
561 del (Avail n) | keep n = Just (Avail n)
562 | otherwise = Nothing
563 del (AvailTC n ns) | null ns' = Nothing
564 | otherwise = Just (AvailTC n ns')
569 ---------------------------------------
571 ---------------------------------------
574 type AvailEnv = NameEnv AvailInfo -- Maps a Name to the AvailInfo that contains it
576 emptyAvailEnv :: AvailEnv
577 emptyAvailEnv = emptyNameEnv
579 unitAvailEnv :: AvailInfo -> AvailEnv
580 unitAvailEnv a = unitNameEnv (availName a) a
582 plusAvailEnv :: AvailEnv -> AvailEnv -> AvailEnv
583 plusAvailEnv = plusNameEnv_C plusAvail
585 lookupAvailEnv = lookupNameEnv
587 availEnvElts = nameEnvElts
589 addAvail :: AvailEnv -> AvailInfo -> AvailEnv
590 addAvail avails avail = extendNameEnv_C plusAvail avails (availName avail) avail
592 mkAvailEnv :: [AvailInfo] -> AvailEnv
593 -- 'avails' may have several items with the same availName
594 -- E.g import Ix( Ix(..), index )
595 -- will give Ix(Ix,index,range) and Ix(index)
596 -- We want to combine these; addAvail does that
597 mkAvailEnv avails = foldl addAvail emptyAvailEnv avails
600 %************************************************************************
602 \subsection{Where from}
604 %************************************************************************
606 The @WhereFrom@ type controls where the renamer looks for an interface file
610 = ImportByUser IsBootInterface -- Ordinary user import (perhaps {-# SOURCE #-})
612 | ImportForUsage IsBootInterface -- Import when chasing usage info from an interaface file
613 -- Failure in this case is not an error
615 | ImportBySystem -- Non user import.
617 instance Outputable WhereFrom where
618 ppr (ImportByUser is_boot) | is_boot = ptext SLIT("{- SOURCE -}")
620 ppr (ImportForUsage is_boot) | is_boot = ptext SLIT("{- USAGE SOURCE -}")
621 | otherwise = ptext SLIT("{- USAGE -}")
622 ppr ImportBySystem = ptext SLIT("{- SYSTEM -}")
626 %************************************************************************
628 \subsection[Inst-types]{@Inst@ types}
630 v%************************************************************************
632 An @Inst@ is either a dictionary, an instance of an overloaded
633 literal, or an instance of an overloaded value. We call the latter a
634 ``method'' even though it may not correspond to a class operation.
635 For example, we might have an instance of the @double@ function at
636 type Int, represented by
638 Method 34 doubleId [Int] origin
650 TcId -- The overloaded function
651 -- This function will be a global, local, or ClassOpId;
652 -- inside instance decls (only) it can also be an InstId!
653 -- The id needn't be completely polymorphic.
654 -- You'll probably find its name (for documentation purposes)
655 -- inside the InstOrigin
657 [TcType] -- The types to which its polymorphic tyvars
658 -- should be instantiated.
659 -- These types must saturate the Id's foralls.
661 TcThetaType -- The (types of the) dictionaries to which the function
662 -- must be applied to get the method
664 TcTauType -- The type of the method
668 -- INVARIANT: in (Method u f tys theta tau loc)
669 -- type of (f tys dicts(from theta)) = tau
673 HsOverLit -- The literal from the occurrence site
674 -- INVARIANT: never a rebindable-syntax literal
675 -- Reason: tcSyntaxName does unification, and we
676 -- don't want to deal with that during tcSimplify
677 TcType -- The type at which the literal is used
681 @Insts@ are ordered by their class/type info, rather than by their
682 unique. This allows the context-reduction mechanism to use standard finite
683 maps to do their stuff.
686 instance Ord Inst where
689 instance Eq Inst where
690 (==) i1 i2 = case i1 `cmpInst` i2 of
694 cmpInst (Dict _ pred1 _) (Dict _ pred2 _) = pred1 `tcCmpPred` pred2
695 cmpInst (Dict _ _ _) other = LT
697 cmpInst (Method _ _ _ _ _ _) (Dict _ _ _) = GT
698 cmpInst (Method _ id1 tys1 _ _ _) (Method _ id2 tys2 _ _ _) = (id1 `compare` id2) `thenCmp` (tys1 `tcCmpTypes` tys2)
699 cmpInst (Method _ _ _ _ _ _) other = LT
701 cmpInst (LitInst _ _ _ _) (Dict _ _ _) = GT
702 cmpInst (LitInst _ _ _ _) (Method _ _ _ _ _ _) = GT
703 cmpInst (LitInst _ lit1 ty1 _) (LitInst _ lit2 ty2 _) = (lit1 `compare` lit2) `thenCmp` (ty1 `tcCmpType` ty2)
707 %************************************************************************
709 \subsection[Inst-collections]{LIE: a collection of Insts}
711 %************************************************************************
716 isEmptyLIE = isEmptyBag
718 unitLIE inst = unitBag inst
719 mkLIE insts = listToBag insts
720 plusLIE lie1 lie2 = lie1 `unionBags` lie2
721 consLIE inst lie = inst `consBag` lie
722 plusLIEs lies = unionManyBags lies
723 lieToList = bagToList
724 listToLIE = listToBag
728 %************************************************************************
730 \subsection[Inst-origin]{The @InstOrigin@ type}
732 %************************************************************************
734 The @InstOrigin@ type gives information about where a dictionary came from.
735 This is important for decent error message reporting because dictionaries
736 don't appear in the original source code. Doubtless this type will evolve...
738 It appears in TcMonad because there are a couple of error-message-generation
739 functions that deal with it.
742 type InstLoc = (InstOrigin, SrcLoc, ErrCtxt)
745 = OccurrenceOf Name -- Occurrence of an overloaded identifier
747 | IPOcc (IPName Name) -- Occurrence of an implicit parameter
748 | IPBind (IPName Name) -- Binding site of an implicit parameter
752 | DataDeclOrigin -- Typechecking a data declaration
754 | InstanceDeclOrigin -- Typechecking an instance decl
756 | LiteralOrigin HsOverLit -- Occurrence of a literal
758 | PatOrigin RenamedPat
760 | ArithSeqOrigin RenamedArithSeqInfo -- [x..], [x..y] etc
761 | PArrSeqOrigin RenamedArithSeqInfo -- [:x..y:] and [:x,y..z:]
763 | SignatureOrigin -- A dict created from a type signature
764 | Rank2Origin -- A dict created when typechecking the argument
765 -- of a rank-2 typed function
767 | DoOrigin -- The monad for a do expression
769 | ClassDeclOrigin -- Manufactured during a class decl
771 | InstanceSpecOrigin Class -- in a SPECIALIZE instance pragma
774 -- When specialising instances the instance info attached to
775 -- each class is not yet ready, so we record it inside the
776 -- origin information. This is a bit of a hack, but it works
777 -- fine. (Patrick is to blame [WDP].)
779 | ValSpecOrigin Name -- in a SPECIALIZE pragma for a value
781 -- Argument or result of a ccall
782 -- Dictionaries with this origin aren't actually mentioned in the
783 -- translated term, and so need not be bound. Nor should they
784 -- be abstracted over.
786 | CCallOrigin String -- CCall label
787 (Maybe RenamedHsExpr) -- Nothing if it's the result
788 -- Just arg, for an argument
790 | LitLitOrigin String -- the litlit
792 | UnknownOrigin -- Help! I give up...
796 pprInstLoc :: InstLoc -> SDoc
797 pprInstLoc (orig, locn, ctxt)
798 = hsep [text "arising from", pp_orig orig, text "at", ppr locn]
800 pp_orig (OccurrenceOf name)
801 = hsep [ptext SLIT("use of"), quotes (ppr name)]
803 = hsep [ptext SLIT("use of implicit parameter"), quotes (ppr name)]
804 pp_orig (IPBind name)
805 = hsep [ptext SLIT("binding for implicit parameter"), quotes (ppr name)]
806 pp_orig RecordUpdOrigin
807 = ptext SLIT("a record update")
808 pp_orig DataDeclOrigin
809 = ptext SLIT("the data type declaration")
810 pp_orig InstanceDeclOrigin
811 = ptext SLIT("the instance declaration")
812 pp_orig (LiteralOrigin lit)
813 = hsep [ptext SLIT("the literal"), quotes (ppr lit)]
814 pp_orig (PatOrigin pat)
815 = hsep [ptext SLIT("the pattern"), quotes (ppr pat)]
816 pp_orig (ArithSeqOrigin seq)
817 = hsep [ptext SLIT("the arithmetic sequence"), quotes (ppr seq)]
818 pp_orig (PArrSeqOrigin seq)
819 = hsep [ptext SLIT("the parallel array sequence"), quotes (ppr seq)]
820 pp_orig (SignatureOrigin)
821 = ptext SLIT("a type signature")
822 pp_orig (Rank2Origin)
823 = ptext SLIT("a function with an overloaded argument type")
825 = ptext SLIT("a do statement")
826 pp_orig (ClassDeclOrigin)
827 = ptext SLIT("a class declaration")
828 pp_orig (InstanceSpecOrigin clas ty)
829 = hsep [text "a SPECIALIZE instance pragma; class",
830 quotes (ppr clas), text "type:", ppr ty]
831 pp_orig (ValSpecOrigin name)
832 = hsep [ptext SLIT("a SPECIALIZE user-pragma for"), quotes (ppr name)]
833 pp_orig (CCallOrigin clabel Nothing{-ccall result-})
834 = hsep [ptext SLIT("the result of the _ccall_ to"), quotes (text clabel)]
835 pp_orig (CCallOrigin clabel (Just arg_expr))
836 = hsep [ptext SLIT("an argument in the _ccall_ to"), quotes (text clabel) <> comma,
837 text "namely", quotes (ppr arg_expr)]
838 pp_orig (LitLitOrigin s)
839 = hsep [ptext SLIT("the ``literal-literal''"), quotes (text s)]
840 pp_orig (UnknownOrigin)
841 = ptext SLIT("...oops -- I don't know where the overloading came from!")