HsUtils.hs 41.2 KB
Newer Older
Austin Seipp's avatar
Austin Seipp committed
1 2
{-
(c) The University of Glasgow, 1992-2006
3

4

5 6
Here we collect a variety of helper functions that construct or
analyse HsSyn.  All these functions deal with generic HsSyn; functions
7
which deal with the instantiated versions are located elsewhere:
8

9
   Parameterised by     Module
10
   ----------------     -------------
11 12 13
   RdrName              parser/RdrHsSyn
   Name                 rename/RnHsSyn
   Id                   typecheck/TcHsSyn
Austin Seipp's avatar
Austin Seipp committed
14
-}
15

16
{-# LANGUAGE CPP #-}
17 18
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE FlexibleContexts #-}
Ian Lynagh's avatar
Ian Lynagh committed
19

20 21 22
module HsUtils(
  -- Terms
  mkHsPar, mkHsApp, mkHsConApp, mkSimpleHsAlt,
23 24
  mkSimpleMatch, unguardedGRHSs, unguardedRHS,
  mkMatchGroup, mkMatchGroupName, mkMatch, mkHsLam, mkHsIf,
25
  mkHsWrap, mkLHsWrap, mkHsWrapCo, mkHsWrapCoR, mkLHsWrapCo,
26
  coToHsWrapper, coToHsWrapperR, mkHsDictLet, mkHsLams,
27
  mkHsOpApp, mkHsDo, mkHsComp, mkHsWrapPat, mkHsWrapPatCo,
28
  mkLHsPar, mkHsCmdCast,
29

30
  nlHsTyApp, nlHsTyApps, nlHsVar, nlHsLit, nlHsApp, nlHsApps, nlHsIntLit, nlHsVarApps,
31
  nlHsDo, nlHsOpApp, nlHsLam, nlHsPar, nlHsIf, nlHsCase, nlList,
32 33
  mkLHsTupleExpr, mkLHsVarTuple, missingTupArg,
  toHsType, toHsKind,
34

Simon Marlow's avatar
Simon Marlow committed
35 36 37 38
  -- * Constructing general big tuples
  -- $big_tuples
  mkChunkified, chunkify,

39
  -- Bindings
Simon Marlow's avatar
Simon Marlow committed
40 41
  mkFunBind, mkVarBind, mkHsVarBind, mk_easy_FunBind, mkTopFunBind,
  mkPatSynBind,
42 43

  -- Literals
44
  mkHsIntegral, mkHsFractional, mkHsIsString, mkHsString, mkHsStringPrimLit,
45 46

  -- Patterns
47
  mkNPat, mkNPlusKPat, nlVarPat, nlLitPat, nlConVarPat, nlConVarPatName, nlConPat,
48 49
  nlConPatName, nlInfixConPat, nlNullaryConPat, nlWildConPat, nlWildPat,
  nlWildPatName, nlWildPatId, nlTuplePat, mkParPat,
Simon Marlow's avatar
Simon Marlow committed
50
  mkBigLHsVarTup, mkBigLHsTup, mkBigLHsVarPatTup, mkBigLHsPatTup,
51 52 53

  -- Types
  mkHsAppTy, userHsTyVarBndrs,
54
  nlHsAppTy, nlHsTyVar, nlHsFunTy, nlHsTyConApp,
55 56

  -- Stmts
57
  mkTransformStmt, mkTransformByStmt, mkBodyStmt, mkBindStmt, mkLastStmt,
58 59
  emptyTransStmt, mkGroupUsingStmt, mkGroupByUsingStmt,
  emptyRecStmt, emptyRecStmtName, emptyRecStmtId, mkRecStmt,
60 61

  -- Template Haskell
62
  mkHsSpliceTy, mkHsSpliceE, mkHsSpliceTE, mkUntypedSplice,
63
  mkHsQuasiQuote, unqualQuasiQuote,
64 65

  -- Flags
66
  noRebindableInfo,
67 68

  -- Collecting binders
69
  collectLocalBinders, collectHsValBinders, collectHsBindListBinders,
70
  collectHsIdBinders,
71 72 73 74
  collectHsBindsBinders, collectHsBindBinders, collectMethodBinders,
  collectPatBinders, collectPatsBinders,
  collectLStmtsBinders, collectStmtsBinders,
  collectLStmtBinders, collectStmtBinders,
75

76
  hsLTyClDeclBinders, hsTyClForeignBinders, hsPatSynBinders,
77
  hsForeignDeclsBinders, hsGroupBinders, hsDataFamInstBinders,
78

79 80
  -- Collecting implicit binders
  lStmtsImplicits, hsValBindsImplicits, lPatImplicits
81
  ) where
82

83 84
#include "HsVersions.h"

85
import HsDecls
86 87 88
import HsBinds
import HsExpr
import HsPat
89
import HsTypes
90
import HsLit
91
import PlaceHolder
92

93
import TcEvidence
94 95
import RdrName
import Var
96
import TypeRep
97 98
import TcType
import Kind
99 100
import DataCon
import Name
101
import NameSet
102
import BasicTypes
103
import SrcLoc
104 105
import FastString
import Util
106
import Bag
107
import Outputable
Simon Marlow's avatar
Simon Marlow committed
108
import Constants
109

110
import Data.Either
111 112
import Data.Function
import Data.List
113

114 115 116 117 118
#if __GLASGOW_HASKELL__ < 709
import Data.Foldable ( foldMap )
import Data.Monoid ( mempty, mappend )
#endif

Austin Seipp's avatar
Austin Seipp committed
119 120 121
{-
************************************************************************
*                                                                      *
122
        Some useful helpers for constructing syntax
Austin Seipp's avatar
Austin Seipp committed
123 124
*                                                                      *
************************************************************************
125

126 127 128
These functions attempt to construct a not-completely-useless SrcSpan
from their components, compared with the nl* functions below which
just attach noSrcSpan to everything.
Austin Seipp's avatar
Austin Seipp committed
129
-}
130 131 132 133

mkHsPar :: LHsExpr id -> LHsExpr id
mkHsPar e = L (getLoc e) (HsPar e)

134
mkSimpleMatch :: [LPat id] -> Located (body id) -> LMatch id (Located (body id))
135
mkSimpleMatch pats rhs
136
  = L loc $
Alan Zimmerman's avatar
Alan Zimmerman committed
137
    Match Nothing pats Nothing (unguardedGRHSs rhs)
138 139
  where
    loc = case pats of
140 141
                []      -> getLoc rhs
                (pat:_) -> combineSrcSpans (getLoc pat) (getLoc rhs)
142

143
unguardedGRHSs :: Located (body id) -> GRHSs id (Located (body id))
144
unguardedGRHSs rhs@(L loc _) = GRHSs (unguardedRHS loc rhs) emptyLocalBinds
145

Alan Zimmerman's avatar
Alan Zimmerman committed
146 147
unguardedRHS :: SrcSpan -> Located (body id) -> [LGRHS id (Located (body id))]
unguardedRHS loc rhs = [L loc (GRHS [] rhs)]
148

149 150
mkMatchGroup :: Origin -> [LMatch RdrName (Located (body RdrName))]
             -> MatchGroup RdrName (Located (body RdrName))
151
mkMatchGroup origin matches = MG { mg_alts = matches, mg_arg_tys = []
152 153 154 155 156
                                 , mg_res_ty = placeHolderType
                                 , mg_origin = origin }

mkMatchGroupName :: Origin -> [LMatch Name (Located (body Name))]
             -> MatchGroup Name (Located (body Name))
157
mkMatchGroupName origin matches = MG { mg_alts = matches, mg_arg_tys = []
158 159
                                     , mg_res_ty = placeHolderType
                                     , mg_origin = origin }
160

161 162 163 164 165 166
mkHsAppTy :: LHsType name -> LHsType name -> LHsType name
mkHsAppTy t1 t2 = addCLoc t1 t2 (HsAppTy t1 t2)

mkHsApp :: LHsExpr name -> LHsExpr name -> LHsExpr name
mkHsApp e1 e2 = addCLoc e1 e2 (HsApp e1 e2)

167
mkHsLam :: [LPat RdrName] -> LHsExpr RdrName -> LHsExpr RdrName
168
mkHsLam pats body = mkHsPar (L (getLoc body) (HsLam matches))
169
        where
170
          matches = mkMatchGroup Generated [mkSimpleMatch pats body]
171 172

mkHsLams :: [TyVar] -> [EvVar] -> LHsExpr Id -> LHsExpr Id
173 174
mkHsLams tyvars dicts expr = mkLHsWrap (mkWpTyLams tyvars
                                       <.> mkWpLams dicts) expr
175 176

mkHsConApp :: DataCon -> [Type] -> [HsExpr Id] -> LHsExpr Id
177 178
-- Used for constructing dictionary terms etc, so no locations
mkHsConApp data_con tys args
179 180 181 182
  = foldl mk_app (nlHsTyApp (dataConWrapId data_con) tys) args
  where
    mk_app f a = noLoc (HsApp f (noLoc a))

183
mkSimpleHsAlt :: LPat id -> (Located (body id)) -> LMatch id (Located (body id))
184
-- A simple lambda with a single pattern, no binds, no guards; pre-typechecking
185
mkSimpleHsAlt pat expr
186 187
  = mkSimpleMatch [pat] expr

188
nlHsTyApp :: name -> [Type] -> LHsExpr name
189
nlHsTyApp fun_id tys = noLoc (HsWrap (mkWpTyApps tys) (HsVar fun_id))
190

191 192 193
nlHsTyApps :: name -> [Type] -> [LHsExpr name] -> LHsExpr name
nlHsTyApps fun_id tys xs = foldl nlHsApp (nlHsTyApp fun_id tys) xs

194 195 196 197 198 199 200 201 202 203 204
--------- Adding parens ---------
mkLHsPar :: LHsExpr name -> LHsExpr name
-- Wrap in parens if hsExprNeedsParens says it needs them
-- So   'f x'  becomes '(f x)', but '3' stays as '3'
mkLHsPar le@(L loc e) | hsExprNeedsParens e = L loc (HsPar le)
                      | otherwise           = le

mkParPat :: LPat name -> LPat name
mkParPat lp@(L loc p) | hsPatNeedsParens p = L loc (ParPat lp)
                      | otherwise          = lp

205

206
-------------------------------
207 208 209
-- These are the bits of syntax that contain rebindable names
-- See RnEnv.lookupSyntaxName

210
mkHsIntegral   :: String -> Integer -> PostTc RdrName Type -> HsOverLit RdrName
211
mkHsFractional :: FractionalLit -> PostTc RdrName Type -> HsOverLit RdrName
212
mkHsIsString :: String -> FastString -> PostTc RdrName Type -> HsOverLit RdrName
213 214 215
mkHsDo         :: HsStmtContext Name -> [ExprLStmt RdrName] -> HsExpr RdrName
mkHsComp       :: HsStmtContext Name -> [ExprLStmt RdrName] -> LHsExpr RdrName
               -> HsExpr RdrName
twanvl's avatar
twanvl committed
216

Alan Zimmerman's avatar
Alan Zimmerman committed
217 218
mkNPat      :: Located (HsOverLit id) -> Maybe (SyntaxExpr id) -> Pat id
mkNPlusKPat :: Located id -> Located (HsOverLit id) -> Pat id
twanvl's avatar
twanvl committed
219

220
mkLastStmt :: Located (bodyR idR) -> StmtLR idL idR (Located (bodyR idR))
221 222
mkBodyStmt :: Located (bodyR RdrName)
           -> StmtLR idL RdrName (Located (bodyR RdrName))
223
mkBindStmt :: LPat idL -> Located (bodyR idR) -> StmtLR idL idR (Located (bodyR idR))
224

225 226 227 228
emptyRecStmt     :: StmtLR idL  RdrName bodyR
emptyRecStmtName :: StmtLR Name Name    bodyR
emptyRecStmtId   :: StmtLR Id   Id      bodyR
mkRecStmt    :: [LStmtLR idL RdrName bodyR] -> StmtLR idL RdrName bodyR
twanvl's avatar
twanvl committed
229 230


231 232 233
mkHsIntegral src i  = OverLit (HsIntegral   src i) noRebindableInfo noSyntaxExpr
mkHsFractional   f  = OverLit (HsFractional     f) noRebindableInfo noSyntaxExpr
mkHsIsString src s  = OverLit (HsIsString   src s) noRebindableInfo noSyntaxExpr
234

235 236
noRebindableInfo :: PlaceHolder
noRebindableInfo = PlaceHolder -- Just another placeholder;
237

238
mkHsDo ctxt stmts = HsDo ctxt stmts placeHolderType
239 240 241
mkHsComp ctxt stmts expr = mkHsDo ctxt (stmts ++ [last_stmt])
  where
    last_stmt = L (getLoc expr) $ mkLastStmt expr
242

243 244 245
mkHsIf :: LHsExpr id -> LHsExpr id -> LHsExpr id -> HsExpr id
mkHsIf c a b = HsIf (Just noSyntaxExpr) c a b

246
mkNPat lit neg     = NPat lit neg noSyntaxExpr
247
mkNPlusKPat id lit = NPlusKPat id lit noSyntaxExpr noSyntaxExpr
248

249 250 251 252 253 254 255 256
mkTransformStmt    :: [ExprLStmt idL] -> LHsExpr idR
                   -> StmtLR idL idR (LHsExpr idL)
mkTransformByStmt  :: [ExprLStmt idL] -> LHsExpr idR -> LHsExpr idR
                   -> StmtLR idL idR (LHsExpr idL)
mkGroupUsingStmt   :: [ExprLStmt idL]                -> LHsExpr idR
                   -> StmtLR idL idR (LHsExpr idL)
mkGroupByUsingStmt :: [ExprLStmt idL] -> LHsExpr idR -> LHsExpr idR
                   -> StmtLR idL idR (LHsExpr idL)
257

258
emptyTransStmt :: StmtLR idL idR (LHsExpr idR)
259
emptyTransStmt = TransStmt { trS_form = panic "emptyTransStmt: form"
260
                           , trS_stmts = [], trS_bndrs = []
261 262 263
                           , trS_by = Nothing, trS_using = noLoc noSyntaxExpr
                           , trS_ret = noSyntaxExpr, trS_bind = noSyntaxExpr
                           , trS_fmap = noSyntaxExpr }
264 265 266 267
mkTransformStmt    ss u   = emptyTransStmt { trS_form = ThenForm,  trS_stmts = ss, trS_using = u }
mkTransformByStmt  ss u b = emptyTransStmt { trS_form = ThenForm,  trS_stmts = ss, trS_using = u, trS_by = Just b }
mkGroupUsingStmt   ss u   = emptyTransStmt { trS_form = GroupForm, trS_stmts = ss, trS_using = u }
mkGroupByUsingStmt ss b u = emptyTransStmt { trS_form = GroupForm, trS_stmts = ss, trS_using = u, trS_by = Just b }
268

Simon Marlow's avatar
Simon Marlow committed
269
mkLastStmt body     = LastStmt body False noSyntaxExpr
270 271
mkBodyStmt body     = BodyStmt body noSyntaxExpr noSyntaxExpr placeHolderType
mkBindStmt pat body = BindStmt pat body noSyntaxExpr noSyntaxExpr
272 273


274 275 276 277 278 279 280 281 282 283 284 285 286 287 288
emptyRecStmt' :: forall idL idR body.
                       PostTc idR Type -> StmtLR idL idR body
emptyRecStmt' tyVal =
   RecStmt
     { recS_stmts = [], recS_later_ids = []
     , recS_rec_ids = []
     , recS_ret_fn = noSyntaxExpr
     , recS_mfix_fn = noSyntaxExpr
     , recS_bind_fn = noSyntaxExpr, recS_later_rets = []
     , recS_rec_rets = [], recS_ret_ty = tyVal }

emptyRecStmt     = emptyRecStmt' placeHolderType
emptyRecStmtName = emptyRecStmt' placeHolderType
emptyRecStmtId   = emptyRecStmt' placeHolderTypeTc
mkRecStmt stmts  = emptyRecStmt { recS_stmts = stmts }
289 290

-------------------------------
291 292
--- A useful function for building @OpApps@.  The operator is always a
-- variable, and we don't know the fixity yet.
twanvl's avatar
twanvl committed
293
mkHsOpApp :: LHsExpr id -> id -> LHsExpr id -> HsExpr id
294 295
mkHsOpApp e1 op e2 = OpApp e1 (noLoc (HsVar op)) (error "mkOpApp:fixity") e2

296 297 298
unqualSplice :: RdrName
unqualSplice = mkRdrUnqual (mkVarOccFS (fsLit "splice"))

299 300 301
mkUntypedSplice :: LHsExpr RdrName -> HsSplice RdrName
mkUntypedSplice e = HsUntypedSplice unqualSplice e

302
mkHsSpliceE :: LHsExpr RdrName -> HsExpr RdrName
303
mkHsSpliceE e = HsSpliceE (mkUntypedSplice e)
304 305

mkHsSpliceTE :: LHsExpr RdrName -> HsExpr RdrName
306
mkHsSpliceTE e = HsSpliceE (HsTypedSplice unqualSplice e)
307

308
mkHsSpliceTy :: LHsExpr RdrName -> HsType RdrName
309
mkHsSpliceTy e = HsSpliceTy (HsUntypedSplice unqualSplice e) placeHolderKind
310

311 312
mkHsQuasiQuote :: RdrName -> SrcSpan -> FastString -> HsSplice RdrName
mkHsQuasiQuote quoter span quote = HsQuasiQuote unqualSplice quoter span quote
313

twanvl's avatar
twanvl committed
314
unqualQuasiQuote :: RdrName
Ian Lynagh's avatar
Ian Lynagh committed
315
unqualQuasiQuote = mkRdrUnqual (mkVarOccFS (fsLit "quasiquote"))
316 317
                -- A name (uniquified later) to
                -- identify the quasi-quote
318

twanvl's avatar
twanvl committed
319
mkHsString :: String -> HsLit
320
mkHsString s = HsString s (mkFastString s)
321

322 323 324 325
mkHsStringPrimLit :: FastString -> HsLit
mkHsStringPrimLit fs
  = HsStringPrim (unpackFS fs) (fastStringToByteString fs)

326
-------------
327
userHsTyVarBndrs :: SrcSpan -> [name] -> [Located (HsTyVarBndr name)]
328
-- Caller sets location
329
userHsTyVarBndrs loc bndrs = [ L loc (UserTyVar v) | v <- bndrs ]
330

Austin Seipp's avatar
Austin Seipp committed
331 332 333
{-
************************************************************************
*                                                                      *
334
        Constructing syntax with no location info
Austin Seipp's avatar
Austin Seipp committed
335 336 337
*                                                                      *
************************************************************************
-}
338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353

nlHsVar :: id -> LHsExpr id
nlHsVar n = noLoc (HsVar n)

nlHsLit :: HsLit -> LHsExpr id
nlHsLit n = noLoc (HsLit n)

nlVarPat :: id -> LPat id
nlVarPat n = noLoc (VarPat n)

nlLitPat :: HsLit -> LPat id
nlLitPat l = noLoc (LitPat l)

nlHsApp :: LHsExpr id -> LHsExpr id -> LHsExpr id
nlHsApp f x = noLoc (HsApp f x)

twanvl's avatar
twanvl committed
354
nlHsIntLit :: Integer -> LHsExpr id
355
nlHsIntLit n = noLoc (HsLit (HsInt (show n) n))
356 357 358

nlHsApps :: id -> [LHsExpr id] -> LHsExpr id
nlHsApps f xs = foldl nlHsApp (nlHsVar f) xs
359

360 361
nlHsVarApps :: id -> [id] -> LHsExpr id
nlHsVarApps f xs = noLoc (foldl mk (HsVar f) (map HsVar xs))
362 363
                 where
                   mk f a = HsApp (noLoc f) (noLoc a)
364

365
nlConVarPat :: RdrName -> [RdrName] -> LPat RdrName
366 367
nlConVarPat con vars = nlConPat con (map nlVarPat vars)

368 369 370
nlConVarPatName :: Name -> [Name] -> LPat Name
nlConVarPatName con vars = nlConPatName con (map nlVarPat vars)

371 372 373
nlInfixConPat :: id -> LPat id -> LPat id -> LPat id
nlInfixConPat con l r = noLoc (ConPatIn (noLoc con) (InfixCon l r))

374
nlConPat :: RdrName -> [LPat RdrName] -> LPat RdrName
375 376
nlConPat con pats = noLoc (ConPatIn (noLoc con) (PrefixCon pats))

377 378 379
nlConPatName :: Name -> [LPat Name] -> LPat Name
nlConPatName con pats = noLoc (ConPatIn (noLoc con) (PrefixCon pats))

380 381 382 383 384
nlNullaryConPat :: id -> LPat id
nlNullaryConPat con = noLoc (ConPatIn (noLoc con) (PrefixCon []))

nlWildConPat :: DataCon -> LPat RdrName
nlWildConPat con = noLoc (ConPatIn (noLoc (getRdrName con))
385 386
                         (PrefixCon (nOfThem (dataConSourceArity con)
                                             nlWildPat)))
387

388 389
nlWildPat :: LPat RdrName
nlWildPat  = noLoc (WildPat placeHolderType )  -- Pre-typechecking
390

391 392 393 394 395 396 397 398
nlWildPatName :: LPat Name
nlWildPatName  = noLoc (WildPat placeHolderType )  -- Pre-typechecking

nlWildPatId :: LPat Id
nlWildPatId  = noLoc (WildPat placeHolderTypeTc )  -- Post-typechecking

nlHsDo :: HsStmtContext Name -> [LStmt RdrName (LHsExpr RdrName)]
       -> LHsExpr RdrName
399
nlHsDo ctxt stmts = noLoc (mkHsDo ctxt stmts)
400

twanvl's avatar
twanvl committed
401
nlHsOpApp :: LHsExpr id -> id -> LHsExpr id -> LHsExpr id
402 403
nlHsOpApp e1 op e2 = noLoc (mkHsOpApp e1 op e2)

404
nlHsLam  :: LMatch RdrName (LHsExpr RdrName) -> LHsExpr RdrName
twanvl's avatar
twanvl committed
405 406
nlHsPar  :: LHsExpr id -> LHsExpr id
nlHsIf   :: LHsExpr id -> LHsExpr id -> LHsExpr id -> LHsExpr id
407 408 409
nlHsCase :: LHsExpr RdrName -> [LMatch RdrName (LHsExpr RdrName)]
         -> LHsExpr RdrName
nlList   :: [LHsExpr RdrName] -> LHsExpr RdrName
twanvl's avatar
twanvl committed
410

411
nlHsLam match          = noLoc (HsLam (mkMatchGroup Generated [match]))
412 413 414 415
nlHsPar e              = noLoc (HsPar e)
nlHsIf cond true false = noLoc (mkHsIf cond true false)
nlHsCase expr matches  = noLoc (HsCase expr (mkMatchGroup Generated matches))
nlList exprs           = noLoc (ExplicitList placeHolderType Nothing exprs)
416

twanvl's avatar
twanvl committed
417 418 419 420
nlHsAppTy :: LHsType name -> LHsType name -> LHsType name
nlHsTyVar :: name                         -> LHsType name
nlHsFunTy :: LHsType name -> LHsType name -> LHsType name

421 422 423
nlHsAppTy f t           = noLoc (HsAppTy f t)
nlHsTyVar x             = noLoc (HsTyVar x)
nlHsFunTy a b           = noLoc (HsFunTy a b)
424

twanvl's avatar
twanvl committed
425
nlHsTyConApp :: name -> [LHsType name] -> LHsType name
426
nlHsTyConApp tycon tys  = foldl nlHsAppTy (nlHsTyVar tycon) tys
427

Austin Seipp's avatar
Austin Seipp committed
428
{-
429 430
Tuples.  All these functions are *pre-typechecker* because they lack
types on the tuple.
Austin Seipp's avatar
Austin Seipp committed
431
-}
432 433 434 435

mkLHsTupleExpr :: [LHsExpr a] -> LHsExpr a
-- Makes a pre-typechecker boxed tuple, deals with 1 case
mkLHsTupleExpr [e] = e
436
mkLHsTupleExpr es  = noLoc $ ExplicitTuple (map (noLoc . Present) es) Boxed
437 438 439

mkLHsVarTuple :: [a] -> LHsExpr a
mkLHsVarTuple ids  = mkLHsTupleExpr (map nlHsVar ids)
440

441
nlTuplePat :: [LPat id] -> Boxity -> LPat id
442
nlTuplePat pats box = noLoc (TuplePat pats box [])
443

444
missingTupArg :: HsTupArg RdrName
445
missingTupArg = Missing placeHolderType
446

Simon Marlow's avatar
Simon Marlow committed
447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506
mkLHsPatTup :: [LPat id] -> LPat id
mkLHsPatTup []     = noLoc $ TuplePat [] Boxed []
mkLHsPatTup [lpat] = lpat
mkLHsPatTup lpats  = L (getLoc (head lpats)) $ TuplePat lpats Boxed []

-- The Big equivalents for the source tuple expressions
mkBigLHsVarTup :: [id] -> LHsExpr id
mkBigLHsVarTup ids = mkBigLHsTup (map nlHsVar ids)

mkBigLHsTup :: [LHsExpr id] -> LHsExpr id
mkBigLHsTup = mkChunkified mkLHsTupleExpr

-- The Big equivalents for the source tuple patterns
mkBigLHsVarPatTup :: [id] -> LPat id
mkBigLHsVarPatTup bs = mkBigLHsPatTup (map nlVarPat bs)

mkBigLHsPatTup :: [LPat id] -> LPat id
mkBigLHsPatTup = mkChunkified mkLHsPatTup

-- $big_tuples
-- #big_tuples#
--
-- GHCs built in tuples can only go up to 'mAX_TUPLE_SIZE' in arity, but
-- we might concievably want to build such a massive tuple as part of the
-- output of a desugaring stage (notably that for list comprehensions).
--
-- We call tuples above this size \"big tuples\", and emulate them by
-- creating and pattern matching on >nested< tuples that are expressible
-- by GHC.
--
-- Nesting policy: it's better to have a 2-tuple of 10-tuples (3 objects)
-- than a 10-tuple of 2-tuples (11 objects), so we want the leaves of any
-- construction to be big.
--
-- If you just use the 'mkBigCoreTup', 'mkBigCoreVarTupTy', 'mkTupleSelector'
-- and 'mkTupleCase' functions to do all your work with tuples you should be
-- fine, and not have to worry about the arity limitation at all.

-- | Lifts a \"small\" constructor into a \"big\" constructor by recursive decompositon
mkChunkified :: ([a] -> a)      -- ^ \"Small\" constructor function, of maximum input arity 'mAX_TUPLE_SIZE'
             -> [a]             -- ^ Possible \"big\" list of things to construct from
             -> a               -- ^ Constructed thing made possible by recursive decomposition
mkChunkified small_tuple as = mk_big_tuple (chunkify as)
  where
        -- Each sub-list is short enough to fit in a tuple
    mk_big_tuple [as] = small_tuple as
    mk_big_tuple as_s = mk_big_tuple (chunkify (map small_tuple as_s))

chunkify :: [a] -> [[a]]
-- ^ Split a list into lists that are small enough to have a corresponding
-- tuple arity. The sub-lists of the result all have length <= 'mAX_TUPLE_SIZE'
-- But there may be more than 'mAX_TUPLE_SIZE' sub-lists
chunkify xs
  | n_xs <= mAX_TUPLE_SIZE = [xs]
  | otherwise              = split xs
  where
    n_xs     = length xs
    split [] = []
    split xs = take mAX_TUPLE_SIZE xs : split (drop mAX_TUPLE_SIZE xs)

Austin Seipp's avatar
Austin Seipp committed
507 508 509
{-
************************************************************************
*                                                                      *
510
        Converting a Type to an HsType RdrName
Austin Seipp's avatar
Austin Seipp committed
511 512
*                                                                      *
************************************************************************
513 514

This is needed to implement GeneralizedNewtypeDeriving.
Austin Seipp's avatar
Austin Seipp committed
515
-}
516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533

toHsType :: Type -> LHsType RdrName
toHsType ty
  | [] <- tvs_only
  , [] <- theta
  = to_hs_type tau
  | otherwise
  = noLoc $
    mkExplicitHsForAllTy (map mk_hs_tvb tvs_only)
                         (noLoc $ map toHsType theta)
                         (to_hs_type tau)

  where
    (tvs, theta, tau) = tcSplitSigmaTy ty
    tvs_only = filter isTypeVar tvs

    to_hs_type (TyVarTy tv) = nlHsTyVar (getRdrName tv)
    to_hs_type (AppTy t1 t2) = nlHsAppTy (toHsType t1) (toHsType t2)
534
    to_hs_type (TyConApp tc args) = nlHsTyConApp (getRdrName tc) (map toHsType args')
535
       where
Simon Peyton Jones's avatar
Simon Peyton Jones committed
536 537 538
         args' = filterOut isKind args
         -- Source-language types have _implicit_ kind arguments,
         -- so we must remove them here (Trac #8563)
539 540 541
    to_hs_type (FunTy arg res) = ASSERT( not (isConstraintKind (typeKind arg)) )
                                 nlHsFunTy (toHsType arg) (toHsType res)
    to_hs_type t@(ForAllTy {}) = pprPanic "toHsType" (ppr t)
Alan Zimmerman's avatar
Alan Zimmerman committed
542 543
    to_hs_type (LitTy (NumTyLit n)) = noLoc $ HsTyLit (HsNumTy "" n)
    to_hs_type (LitTy (StrTyLit s)) = noLoc $ HsTyLit (HsStrTy "" s)
544

Alan Zimmerman's avatar
Alan Zimmerman committed
545 546
    mk_hs_tvb tv = noLoc $ KindedTyVar (noLoc (getRdrName tv))
                                       (toHsKind (tyVarKind tv))
547 548 549 550

toHsKind :: Kind -> LHsKind RdrName
toHsKind = toHsType

551 552 553 554 555 556
--------- HsWrappers: type args, dict args, casts ---------
mkLHsWrap :: HsWrapper -> LHsExpr id -> LHsExpr id
mkLHsWrap co_fn (L loc e) = L loc (mkHsWrap co_fn e)

mkHsWrap :: HsWrapper -> HsExpr id -> HsExpr id
mkHsWrap co_fn e | isIdHsWrapper co_fn = e
557
                 | otherwise           = HsWrap co_fn e
558

559
mkHsWrapCo :: TcCoercionN   -- A Nominal coercion  a ~N b
560
           -> HsExpr id -> HsExpr id
Joachim Breitner's avatar
Joachim Breitner committed
561
mkHsWrapCo co e = mkHsWrap (coToHsWrapper co) e
562

563
mkHsWrapCoR :: TcCoercionR   -- A Representational coercion  a ~R b
564 565 566
            -> HsExpr id -> HsExpr id
mkHsWrapCoR co e = mkHsWrap (coToHsWrapperR co) e

567
mkLHsWrapCo :: TcCoercion -> LHsExpr id -> LHsExpr id
Joachim Breitner's avatar
Joachim Breitner committed
568
mkLHsWrapCo co (L loc e) = L loc (mkHsWrapCo co e)
569

570 571 572 573
mkHsCmdCast :: TcCoercion -> HsCmd id -> HsCmd id
mkHsCmdCast co cmd | isTcReflCo co = cmd
                   | otherwise     = HsCmdCast co cmd

574
coToHsWrapper :: TcCoercion -> HsWrapper   -- A Nominal coercion
575
coToHsWrapper co | isTcReflCo co = idHsWrapper
Joachim Breitner's avatar
Joachim Breitner committed
576
                 | otherwise     = mkWpCast (mkTcSubCo co)
577

578 579 580 581
coToHsWrapperR :: TcCoercion -> HsWrapper   -- A Representational coercion
coToHsWrapperR co | isTcReflCo co = idHsWrapper
                  | otherwise     = mkWpCast co

582 583
mkHsWrapPat :: HsWrapper -> Pat id -> Type -> Pat id
mkHsWrapPat co_fn p ty | isIdHsWrapper co_fn = p
584
                       | otherwise           = CoPat co_fn p ty
585

eir@cis.upenn.edu's avatar
eir@cis.upenn.edu committed
586
-- input coercion is Nominal
587 588
mkHsWrapPatCo :: TcCoercion -> Pat id -> Type -> Pat id
mkHsWrapPatCo co pat ty | isTcReflCo co = pat
eir@cis.upenn.edu's avatar
eir@cis.upenn.edu committed
589
                        | otherwise     = CoPat (mkWpCast (mkTcSubCo co)) pat ty
590 591 592

mkHsDictLet :: TcEvBinds -> LHsExpr Id -> LHsExpr Id
mkHsDictLet ev_binds expr = mkLHsWrap (mkWpLet ev_binds) expr
Austin Seipp's avatar
Austin Seipp committed
593 594

{-
595
l
Austin Seipp's avatar
Austin Seipp committed
596 597
************************************************************************
*                                                                      *
598
                Bindings; with a location at the top
Austin Seipp's avatar
Austin Seipp committed
599 600 601
*                                                                      *
************************************************************************
-}
602

603 604
mkFunBind :: Located RdrName -> [LMatch RdrName (LHsExpr RdrName)]
          -> HsBind RdrName
605
-- Not infix, with place holders for coercion and free vars
606
mkFunBind fn ms = FunBind { fun_id = fn, fun_infix = False
607 608
                          , fun_matches = mkMatchGroup Generated ms
                          , fun_co_fn = idHsWrapper
609
                          , bind_fvs = placeHolderNames
610
                          , fun_tick = [] }
611

612 613
mkTopFunBind :: Origin -> Located Name -> [LMatch Name (LHsExpr Name)]
             -> HsBind Name
614
-- In Name-land, with empty bind_fvs
615
mkTopFunBind origin fn ms = FunBind { fun_id = fn, fun_infix = False
616
                                    , fun_matches = mkMatchGroupName origin ms
617
                                    , fun_co_fn = idHsWrapper
618 619
                                    , bind_fvs = emptyNameSet -- NB: closed
                                                              --     binding
620
                                    , fun_tick = [] }
621

622
mkHsVarBind :: SrcSpan -> RdrName -> LHsExpr RdrName -> LHsBind RdrName
623 624 625 626
mkHsVarBind loc var rhs = mk_easy_FunBind loc var [] rhs

mkVarBind :: id -> LHsExpr id -> LHsBind id
mkVarBind var rhs = L (getLoc rhs) $
627
                    VarBind { var_id = var, var_rhs = rhs, var_inline = False }
628

629 630
mkPatSynBind :: Located RdrName -> HsPatSynDetails (Located RdrName)
             -> LPat RdrName -> HsPatSynDir RdrName -> HsBind RdrName
631 632 633 634 635 636 637
mkPatSynBind name details lpat dir = PatSynBind psb
  where
    psb = PSB{ psb_id = name
             , psb_args = details
             , psb_def = lpat
             , psb_dir = dir
             , psb_fvs = placeHolderNames }
cactus's avatar
cactus committed
638

639
------------
640
mk_easy_FunBind :: SrcSpan -> RdrName -> [LPat RdrName]
641
                -> LHsExpr RdrName -> LHsBind RdrName
642
mk_easy_FunBind loc fun pats expr
643
  = L loc $ mkFunBind (L loc fun) [mkMatch pats expr emptyLocalBinds]
644

645
------------
646 647
mkMatch :: [LPat id] -> LHsExpr id -> HsLocalBinds id -> LMatch id (LHsExpr id)
mkMatch pats expr binds
Alan Zimmerman's avatar
Alan Zimmerman committed
648
  = noLoc (Match Nothing (map paren pats) Nothing
649
                 (GRHSs (unguardedRHS noSrcSpan expr) binds))
650
  where
651 652
    paren lp@(L l p) | hsPatNeedsParens p = L l (ParPat lp)
                     | otherwise          = lp
653

Austin Seipp's avatar
Austin Seipp committed
654 655 656
{-
************************************************************************
*                                                                      *
657
        Collecting binders
Austin Seipp's avatar
Austin Seipp committed
658 659
*                                                                      *
************************************************************************
660 661 662 663 664 665 666 667 668 669 670

Get all the binders in some HsBindGroups, IN THE ORDER OF APPEARANCE. eg.

...
where
  (x, y) = ...
  f i j  = ...
  [a, b] = ...

it should return [x, y, f, a, b] (remember, order important).

671 672 673
Note [Collect binders only after renaming]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
These functions should only be used on HsSyn *after* the renamer,
simonpj@microsoft.com's avatar
simonpj@microsoft.com committed
674
to return a [Name] or [Id].  Before renaming the record punning
675 676
and wild-card mechanism makes it hard to know what is bound.
So these functions should not be applied to (HsSyn RdrName)
Austin Seipp's avatar
Austin Seipp committed
677
-}
678 679 680

----------------- Bindings --------------------------
collectLocalBinders :: HsLocalBindsLR idL idR -> [idL]
681 682 683 684
collectLocalBinders (HsValBinds binds) = collectHsIdBinders binds
                                         -- No pattern synonyms here
collectLocalBinders (HsIPBinds _)      = []
collectLocalBinders EmptyLocalBinds    = []
685

686 687 688 689
collectHsIdBinders, collectHsValBinders :: HsValBindsLR idL idR -> [idL]
-- Collect Id binders only, or Ids + pattern synonmys, respectively
collectHsIdBinders  = collect_hs_val_binders True
collectHsValBinders = collect_hs_val_binders False
690 691

collectHsBindBinders :: HsBindLR idL idR -> [idL]
692 693
-- Collect both Ids and pattern-synonym binders
collectHsBindBinders b = collect_bind False b []
694

695
collectHsBindsBinders :: LHsBindsLR idL idR -> [idL]
696
collectHsBindsBinders binds = collect_binds False binds []
697

698
collectHsBindListBinders :: [LHsBindLR idL idR] -> [idL]
699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722
-- Same as collectHsBindsBinders, but works over a list of bindings
collectHsBindListBinders = foldr (collect_bind False . unLoc) []

collect_hs_val_binders :: Bool -> HsValBindsLR idL idR -> [idL]
collect_hs_val_binders ps (ValBindsIn  binds _) = collect_binds     ps binds []
collect_hs_val_binders ps (ValBindsOut binds _) = collect_out_binds ps binds

collect_out_binds :: Bool -> [(RecFlag, LHsBinds id)] -> [id]
collect_out_binds ps = foldr (collect_binds ps . snd) []

collect_binds :: Bool -> LHsBindsLR idL idR -> [idL] -> [idL]
-- Collect Ids, or Ids + patter synonyms, depending on boolean flag
collect_binds ps binds acc = foldrBag (collect_bind ps . unLoc) acc binds

collect_bind :: Bool -> HsBindLR idL idR -> [idL] -> [idL]
collect_bind _ (PatBind { pat_lhs = p })           acc = collect_lpat p acc
collect_bind _ (FunBind { fun_id = L _ f })        acc = f : acc
collect_bind _ (VarBind { var_id = f })            acc = f : acc
collect_bind _ (AbsBinds { abs_exports = dbinds }) acc = map abe_poly dbinds ++ acc
        -- I don't think we want the binders from the abe_binds
        -- The only time we collect binders from a typechecked
        -- binding (hence see AbsBinds) is in zonking in TcHsSyn
collect_bind omitPatSyn (PatSynBind (PSB { psb_id = L _ ps })) acc =
    if omitPatSyn then acc else ps : acc
723

724 725
collectMethodBinders :: LHsBindsLR RdrName idR -> [Located RdrName]
-- Used exclusively for the bindings of an instance decl which are all FunBinds
726
collectMethodBinders binds = foldrBag (get . unLoc) [] binds
727
  where
cactus's avatar
cactus committed
728
    get (FunBind { fun_id = f }) fs = f : fs
729
    get _                        fs = fs
730
       -- Someone else complains about non-FunBinds
731

732
----------------- Statements --------------------------
733
collectLStmtsBinders :: [LStmtLR idL idR body] -> [idL]
734
collectLStmtsBinders = concatMap collectLStmtBinders
735

736
collectStmtsBinders :: [StmtLR idL idR body] -> [idL]
737 738
collectStmtsBinders = concatMap collectStmtBinders

739
collectLStmtBinders :: LStmtLR idL idR body -> [idL]
740 741
collectLStmtBinders = collectStmtBinders . unLoc

742
collectStmtBinders :: StmtLR idL idR body -> [idL]
743
  -- Id Binders for a Stmt... [but what about pattern-sig type vars]?
744 745 746 747 748 749
collectStmtBinders (BindStmt pat _ _ _) = collectPatBinders pat
collectStmtBinders (LetStmt binds)      = collectLocalBinders binds
collectStmtBinders (BodyStmt {})        = []
collectStmtBinders (LastStmt {})        = []
collectStmtBinders (ParStmt xs _ _)     = collectLStmtsBinders
                                        $ [s | ParStmtBlock ss _ _ <- xs, s <- ss]
750 751
collectStmtBinders (TransStmt { trS_stmts = stmts }) = collectLStmtsBinders stmts
collectStmtBinders (RecStmt { recS_stmts = ss })     = collectLStmtsBinders ss
Simon Marlow's avatar
Simon Marlow committed
752
collectStmtBinders ApplicativeStmt{} = []
753 754


755
----------------- Patterns --------------------------
756
collectPatBinders :: LPat a -> [a]
757
collectPatBinders pat = collect_lpat pat []
758 759

collectPatsBinders :: [LPat a] -> [a]
760
collectPatsBinders pats = foldr collect_lpat [] pats
761

762 763 764
-------------
collect_lpat :: LPat name -> [name] -> [name]
collect_lpat (L _ pat) bndrs
765 766
  = go pat
  where
767 768 769 770 771
    go (VarPat var)               = var : bndrs
    go (WildPat _)                = bndrs
    go (LazyPat pat)              = collect_lpat pat bndrs
    go (BangPat pat)              = collect_lpat pat bndrs
    go (AsPat (L _ a) pat)        = a : collect_lpat pat bndrs
772
    go (ViewPat _ pat _)          = collect_lpat pat bndrs
773 774
    go (ParPat  pat)              = collect_lpat pat bndrs

775
    go (ListPat pats _ _)         = foldr collect_lpat bndrs pats
776 777 778
    go (PArrPat pats _)           = foldr collect_lpat bndrs pats
    go (TuplePat pats _ _)        = foldr collect_lpat bndrs pats

779 780
    go (ConPatIn _ ps)            = foldr collect_lpat bndrs (hsConPatArgs ps)
    go (ConPatOut {pat_args=ps})  = foldr collect_lpat bndrs (hsConPatArgs ps)
781 782 783
        -- See Note [Dictionary binders in ConPatOut]
    go (LitPat _)                 = bndrs
    go (NPat _ _ _)               = bndrs
784
    go (NPlusKPat (L _ n) _ _ _)  = n : bndrs
785 786 787

    go (SigPatIn pat _)           = collect_lpat pat bndrs
    go (SigPatOut pat _)          = collect_lpat pat bndrs
gmainland's avatar
gmainland committed
788
    go (SplicePat _)              = bndrs
789
    go (CoPat _ pat _)            = go pat
790

Austin Seipp's avatar
Austin Seipp committed
791
{-
792
Note [Dictionary binders in ConPatOut] See also same Note in DsArrows
793 794 795 796 797 798 799 800 801
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Do *not* gather (a) dictionary and (b) dictionary bindings as binders
of a ConPatOut pattern.  For most calls it doesn't matter, because
it's pre-typechecker and there are no ConPatOuts.  But it does matter
more in the desugarer; for example, DsUtils.mkSelectorBinds uses
collectPatBinders.  In a lazy pattern, for example f ~(C x y) = ...,
we want to generate bindings for x,y but not for dictionaries bound by
C.  (The type checker ensures they would not be used.)

Ross Paterson's avatar
Ross Paterson committed
802 803 804 805 806 807 808 809 810 811 812 813 814 815 816
Desugaring of arrow case expressions needs these bindings (see DsArrows
and arrowcase1), but SPJ (Jan 2007) says it's safer for it to use its
own pat-binder-collector:

Here's the problem.  Consider

data T a where
   C :: Num a => a -> Int -> T a

f ~(C (n+1) m) = (n,m)

Here, the pattern (C (n+1)) binds a hidden dictionary (d::Num a),
and *also* uses that dictionary to match the (n+1) pattern.  Yet, the
variables bound by the lazy pattern are n,m, *not* the dictionary d.
So in mkSelectorBinds in DsUtils, we want just m,n as the variables bound.
Austin Seipp's avatar
Austin Seipp committed
817
-}
Ross Paterson's avatar
Ross Paterson committed
818

819 820 821 822
hsGroupBinders :: HsGroup Name -> [Name]
hsGroupBinders (HsGroup { hs_valds = val_decls, hs_tyclds = tycl_decls,
                          hs_instds = inst_decls, hs_fords = foreign_decls })
  =  collectHsValBinders val_decls
823
  ++ hsTyClForeignBinders tycl_decls inst_decls foreign_decls
824

825 826
hsTyClForeignBinders :: [TyClGroup Name] -> [LInstDecl Name]
                     -> [LForeignDecl Name] -> [Name]
827
-- We need to look at instance declarations too,
828
-- because their associated types may bind data constructors
829
hsTyClForeignBinders tycl_decls inst_decls foreign_decls
830 831 832 833 834 835
  = map unLoc (hsForeignDeclsBinders foreign_decls)
    ++ getSelectorNames (foldMap (foldMap hsLTyClDeclBinders . group_tyclds) tycl_decls
                        `mappend` foldMap hsLInstDeclBinders inst_decls)
  where
    getSelectorNames :: ([Located Name], [LFieldOcc Name]) -> [Name]
    getSelectorNames (ns, fs) = map unLoc ns ++ map (selectorFieldOcc.unLoc) fs
836

837
-------------------
838 839 840 841 842 843
hsLTyClDeclBinders :: Located (TyClDecl name) -> ([Located name], [LFieldOcc name])
-- ^ Returns all the /binding/ names of the decl.  The first one is
-- guaranteed to be the name of the decl. The first component
-- represents all binding names except record fields; the second
-- represents field occurrences. For record fields mentioned in
-- multiple constructors, the SrcLoc will be from the first occurrence.
Simon Peyton Jones's avatar
Simon Peyton Jones committed
844
--
845 846
-- Each returned (Located name) has a SrcSpan for the /whole/ declaration.
-- See Note [SrcSpan for binders]
eir@cis.upenn.edu's avatar
eir@cis.upenn.edu committed
847 848

hsLTyClDeclBinders (L loc (FamDecl { tcdFam = FamilyDecl { fdLName = L _ name } }))
849 850
  = ([L loc name], [])
hsLTyClDeclBinders (L loc (SynDecl     { tcdLName = L _ name })) = ([L loc name], [])
eir@cis.upenn.edu's avatar
eir@cis.upenn.edu committed
851 852
hsLTyClDeclBinders (L loc (ClassDecl   { tcdLName = L _ cls_name
                                       , tcdSigs = sigs, tcdATs = ats }))
853 854 855 856
  = (L loc cls_name :
       [ L fam_loc fam_name | L fam_loc (FamilyDecl { fdLName = L _ fam_name }) <- ats ] ++
       [ L mem_loc mem_name | L mem_loc (TypeSig ns _ _) <- sigs, L _ mem_name <- ns ]
    , [])
eir@cis.upenn.edu's avatar
eir@cis.upenn.edu committed
857
hsLTyClDeclBinders (L loc (DataDecl    { tcdLName = L _ name, tcdDataDefn = defn }))
858
  = (\ (xs, ys) -> (L loc name : xs, ys)) $ hsDataDefnBinders defn
859 860

-------------------
861 862 863 864 865 866
hsForeignDeclsBinders :: [LForeignDecl name] -> [Located name]
-- See Note [SrcSpan for binders]
hsForeignDeclsBinders foreign_decls
  = [ L decl_loc n
    | L decl_loc (ForeignImport (L _ n) _ _ _) <- foreign_decls]

Matthew Pickering's avatar
Matthew Pickering committed
867 868


869
-------------------
Matthew Pickering's avatar
Matthew Pickering committed
870 871
hsPatSynBinders :: HsValBinds RdrName
                -> ([Located RdrName], [Located RdrName])
872 873
-- Collect pattern-synonym binders only, not Ids
-- See Note [SrcSpan for binders]
Matthew Pickering's avatar
Matthew Pickering committed
874
hsPatSynBinders (ValBindsIn binds _) = foldrBag addPatSynBndr ([],[]) binds
875
hsPatSynBinders _ = panic "hsPatSynBinders"
876

Matthew Pickering's avatar
Matthew Pickering committed
877 878
addPatSynBndr :: LHsBindLR id id -> ([Located id], [Located id])
                -> ([Located id], [Located id]) -- (selectors, other)
879
-- See Note [SrcSpan for binders]
Matthew Pickering's avatar
Matthew Pickering committed
880 881 882 883 884 885
addPatSynBndr bind (sels, pss)
  | L bind_loc (PatSynBind (PSB { psb_id = L _ n
                                , psb_args = RecordPatSyn as })) <- bind
  = (map recordPatSynSelectorId as ++ sels, L bind_loc n : pss)
  | L bind_loc (PatSynBind (PSB { psb_id = L _ n})) <- bind
  = (sels, L bind_loc n : pss)
886
  | otherwise
Matthew Pickering's avatar
Matthew Pickering committed
887
  = (sels, pss)
888 889

-------------------
890
hsLInstDeclBinders :: LInstDecl name -> ([Located name], [LFieldOcc name])
891
hsLInstDeclBinders (L _ (ClsInstD { cid_inst = ClsInstDecl { cid_datafam_insts = dfis } }))
892
  = foldMap (hsDataFamInstBinders . unLoc) dfis
893 894
hsLInstDeclBinders (L _ (DataFamInstD { dfid_inst = fi }))
  = hsDataFamInstBinders fi
895
hsLInstDeclBinders (L _ (TyFamInstD {})) = mempty
896 897

-------------------
eir@cis.upenn.edu's avatar
eir@cis.upenn.edu committed
898
-- the SrcLoc returned are for the whole declarations, not just the names
899
hsDataFamInstBinders :: DataFamInstDecl name -> ([Located name], [LFieldOcc name])
900 901 902
hsDataFamInstBinders (DataFamInstDecl { dfid_defn = defn })
  = hsDataDefnBinders defn
  -- There can't be repeated symbols because only data instances have binders
903 904

-------------------
eir@cis.upenn.edu's avatar
eir@cis.upenn.edu committed
905
-- the SrcLoc returned are for the whole declarations, not just the names
906
hsDataDefnBinders :: HsDataDefn name -> ([Located name], [LFieldOcc name])
907 908
hsDataDefnBinders (HsDataDefn { dd_cons = cons })
  = hsConDeclsBinders cons
909
  -- See Note [Binders in family instances]
910

911
-------------------
912
hsConDeclsBinders :: [LConDecl name] -> ([Located name], [LFieldOcc name])
eir@cis.upenn.edu's avatar
eir@cis.upenn.edu committed
913
  -- See hsLTyClDeclBinders for what this does
914 915
  -- The function is boringly complicated because of the records
  -- And since we only have equality, we have to be a little careful
916
hsConDeclsBinders cons = go id cons
917 918 919
  where go :: ([LFieldOcc name] -> [LFieldOcc name])
           -> [LConDecl name] -> ([Located name], [LFieldOcc name])
        go _ [] = ([], [])
920
        go remSeen (r:rs) =
eir@cis.upenn.edu's avatar
eir@cis.upenn.edu committed
921 922
          -- don't re-mangle the location of field names, because we don't
          -- have a record of the full location of the field declaration anyway
923 924 925
          case r of
             -- remove only the first occurrence of any seen field in order to
             -- avoid circumventing detection of duplicate fields (#9156)
926
             L loc (ConDecl { con_names = names, con_details = RecCon flds }) ->
927
               (map (L loc . unLoc) names ++ ns, r' ++ fs)
Alan Zimmerman's avatar
Alan Zimmerman committed
928 929
                  where r' = remSeen (concatMap (cd_fld_names . unLoc)
                                                (unLoc flds))
930 931
                        remSeen' = foldr (.) remSeen [deleteBy ((==) `on` rdrNameFieldOcc . unLoc) v | v <- r']
                        (ns, fs) = go remSeen' rs
932
             L loc (ConDecl { con_names = names }) ->
933 934
                (map (L loc . unLoc) names ++ ns, fs)
                  where (ns, fs) = go remSeen rs
935

Austin Seipp's avatar
Austin Seipp committed
936
{-
937 938 939 940 941 942 943 944 945 946

Note [SrcSpan for binders]
~~~~~~~~~~~~~~~~~~~~~~~~~~
When extracting the (Located RdrNme) for a binder, at least for the
main name (the TyCon of a type declaration etc), we want to give it
the @SrcSpan@ of the whole /declaration/, not just the name itself
(which is how it appears in the syntax tree).  This SrcSpan (for the
entire declaration) is used as the SrcSpan for the Name that is
finally produced, and hence for error messages.  (See Trac #8607.)

947 948
Note [Binders in family instances]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
949
In a type or data family instance declaration, the type
950 951 952 953
constructor is an *occurrence* not a binding site
    type instance T Int = Int -> Int   -- No binders
    data instance S Bool = S1 | S2     -- Binders are S1,S2

954

Austin Seipp's avatar
Austin Seipp committed
955 956
************************************************************************
*                                                                      *