RnTypes.hs 70.3 KB
Newer Older
Austin Seipp's avatar
Austin Seipp committed
1 2 3
{-
(c) The GRASP/AQUA Project, Glasgow University, 1992-1998

4
\section[RnSource]{Main pass of renamer}
Austin Seipp's avatar
Austin Seipp committed
5
-}
6

thomasw's avatar
thomasw committed
7
{-# LANGUAGE ScopedTypeVariables #-}
8
{-# LANGUAGE CPP #-}
9

gmainlan@microsoft.com's avatar
gmainlan@microsoft.com committed
10 11 12
module RnTypes (
        -- Type related stuff
        rnHsType, rnLHsType, rnLHsTypes, rnContext,
eir@cis.upenn.edu's avatar
eir@cis.upenn.edu committed
13
        rnHsKind, rnLHsKind,
14 15 16 17 18
        rnHsSigType, rnHsWcType,
        rnHsSigWcType, rnHsSigWcTypeScoped,
        rnLHsInstType,
        newTyVarNameRn, collectAnonWildCards,
        rnConDeclFields,
19
        rnLTyVar,
20

gmainlan@microsoft.com's avatar
gmainlan@microsoft.com committed
21 22
        -- Precence related stuff
        mkOpAppRn, mkNegAppRn, mkOpFormRn, mkConOpPatRn,
23
        checkPrecMatch, checkSectionPrec,
24

dreixel's avatar
dreixel committed
25
        -- Binding related stuff
eir@cis.upenn.edu's avatar
eir@cis.upenn.edu committed
26
        bindLHsTyVarBndr,
27
        bindSigTyVarsFV, bindHsQTyVars, bindLRdrNames,
eir@cis.upenn.edu's avatar
eir@cis.upenn.edu committed
28
        extractFilteredRdrTyVars,
29
        extractHsTyRdrTyVars, extractHsTysRdrTyVars,
30
        extractHsTysRdrTyVarsDups, rmDupsInRdrTyVars,
31 32
        extractRdrKindSigVars, extractDataDefnKindVars,
        freeKiTyVarsAllVars, freeKiTyVarsKindVars, freeKiTyVarsTypeVars
33
  ) where
34

gmainland's avatar
gmainland committed
35
import {-# SOURCE #-} RnSplice( rnSpliceType )
36

37
import DynFlags
38
import HsSyn
39
import RnHsDoc          ( rnLHsDoc, rnMbLHsDoc )
40
import RnEnv
41 42 43 44 45 46
import RnUnbound        ( perhapsForallMsg )
import RnUtils          ( HsDocContext(..), withHsDocContext, mapFvRn
                        , pprHsDocContext, bindLocalNamesFV, dupNamesErr
                        , newLocalBndrRn, checkShadowedRdrNames )
import RnFixity         ( lookupFieldFixityRn, lookupFixityRn
                        , lookupTyFixityRn )
47
import TcRnMonad
48
import RdrName
49
import PrelNames
50
import TysPrim          ( funTyConName )
51
import TysWiredIn       ( starKindTyConName, unicodeStarKindTyConName )
52 53
import Name
import SrcLoc
54
import NameSet
Adam Gundry's avatar
Adam Gundry committed
55
import FieldLabel
56

57
import Util
gmainlan@microsoft.com's avatar
gmainlan@microsoft.com committed
58
import BasicTypes       ( compareFixity, funTyFixity, negateFixity,
59
                          Fixity(..), FixityDirection(..), LexicalFixity(..) )
60
import Outputable
61
import FastString
62
import Maybes
63 64
import qualified GHC.LanguageExtensions as LangExt

65
import Data.List        ( nubBy, partition )
gmainlan@microsoft.com's avatar
gmainlan@microsoft.com committed
66
import Control.Monad    ( unless, when )
67 68 69

#include "HsVersions.h"

Austin Seipp's avatar
Austin Seipp committed
70
{-
71 72 73
These type renamers are in a separate module, rather than in (say) RnSource,
to break several loop.

Austin Seipp's avatar
Austin Seipp committed
74
*********************************************************
75 76 77
*                                                       *
           HsSigWcType (i.e with wildcards)
*                                                       *
Austin Seipp's avatar
Austin Seipp committed
78 79
*********************************************************
-}
80

81 82
rnHsSigWcType :: HsDocContext -> LHsSigWcType GhcPs
            -> RnM (LHsSigWcType GhcRn, FreeVars)
83 84 85 86
rnHsSigWcType doc sig_ty
  = rn_hs_sig_wc_type True doc sig_ty $ \sig_ty' ->
    return (sig_ty', emptyFVs)

87 88
rnHsSigWcTypeScoped :: HsDocContext -> LHsSigWcType GhcPs
                    -> (LHsSigWcType GhcRn -> RnM (a, FreeVars))
89 90 91 92 93
                    -> RnM (a, FreeVars)
-- Used for
--   - Signatures on binders in a RULE
--   - Pattern type signatures
-- Wildcards are allowed
94
-- type signatures on binders only allowed with ScopedTypeVariables
95
rnHsSigWcTypeScoped ctx sig_ty thing_inside
96 97 98 99
  = do { ty_sig_okay <- xoptM LangExt.ScopedTypeVariables
       ; checkErr ty_sig_okay (unexpectedTypeSigErr sig_ty)
       ; rn_hs_sig_wc_type False ctx sig_ty thing_inside
       }
100
    -- False: for pattern type sigs and rules we /do/ want
Rik Steenkamp's avatar
Rik Steenkamp committed
101
    --        to bring those type variables into scope
102 103 104 105 106
    -- e.g  \ (x :: forall a. a-> b) -> e
    -- Here we do bring 'b' into scope

rn_hs_sig_wc_type :: Bool   -- see rnImplicitBndrs
                  -> HsDocContext
107 108
                  -> LHsSigWcType GhcPs
                  -> (LHsSigWcType GhcRn -> RnM (a, FreeVars))
109 110 111
                  -> RnM (a, FreeVars)
-- rn_hs_sig_wc_type is used for source-language type signatures
rn_hs_sig_wc_type no_implicit_if_forall ctxt
112 113 114 115 116 117 118
                  (HsWC { hswc_body = HsIB { hsib_body = hs_ty }})
                  thing_inside
  = do { free_vars <- extractFilteredRdrTyVars hs_ty
       ; (tv_rdrs, nwc_rdrs) <- partition_nwcs free_vars
       ; rnImplicitBndrs no_implicit_if_forall tv_rdrs hs_ty $ \ vars ->
    do { (wcs, hs_ty', fvs1) <- rnWcBody ctxt nwc_rdrs hs_ty
       ; let sig_ty' = HsWC { hswc_wcs = wcs, hswc_body = ib_ty' }
Richard Eisenberg's avatar
Richard Eisenberg committed
119
             ib_ty'  = mk_implicit_bndrs vars hs_ty' fvs1
120 121
       ; (res, fvs2) <- thing_inside sig_ty'
       ; return (res, fvs1 `plusFV` fvs2) } }
122

123
rnHsWcType :: HsDocContext -> LHsWcType GhcPs -> RnM (LHsWcType GhcRn, FreeVars)
124
rnHsWcType ctxt (HsWC { hswc_body = hs_ty })
eir@cis.upenn.edu's avatar
eir@cis.upenn.edu committed
125
  = do { free_vars <- extractFilteredRdrTyVars hs_ty
126
       ; (_, nwc_rdrs) <- partition_nwcs free_vars
127 128 129 130
       ; (wcs, hs_ty', fvs) <- rnWcBody ctxt nwc_rdrs hs_ty
       ; let sig_ty' = HsWC { hswc_wcs = wcs, hswc_body = hs_ty' }
       ; return (sig_ty', fvs) }

131 132
rnWcBody :: HsDocContext -> [Located RdrName] -> LHsType GhcPs
         -> RnM ([Name], LHsType GhcRn, FreeVars)
133
rnWcBody ctxt nwc_rdrs hs_ty
134
  = do { nwcs <- mapM newLocalBndrRn nwc_rdrs
135
       ; let env = RTKE { rtke_level = TypeLevel
136 137 138
                        , rtke_what  = RnTypeBody
                        , rtke_nwcs  = mkNameSet nwcs
                        , rtke_ctxt  = ctxt }
139 140 141 142 143 144 145 146 147 148
       ; (hs_ty', fvs) <- bindLocalNamesFV nwcs $
                          rn_lty env hs_ty
       ; let awcs = collectAnonWildCards hs_ty'
       ; return (nwcs ++ awcs, hs_ty', fvs) }
  where
    rn_lty env (L loc hs_ty)
      = setSrcSpan loc $
        do { (hs_ty', fvs) <- rn_ty env hs_ty
           ; return (L loc hs_ty', fvs) }

149
    rn_ty :: RnTyKiEnv -> HsType GhcPs -> RnM (HsType GhcRn, FreeVars)
150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177
    -- A lot of faff just to allow the extra-constraints wildcard to appear
    rn_ty env hs_ty@(HsForAllTy { hst_bndrs = tvs, hst_body = hs_body })
      = bindLHsTyVarBndrs (rtke_ctxt env) (Just $ inTypeDoc hs_ty)
                           Nothing [] tvs $ \ _ tvs' _ _ ->
        do { (hs_body', fvs) <- rn_lty env hs_body
           ; return (HsForAllTy { hst_bndrs = tvs', hst_body = hs_body' }, fvs) }

    rn_ty env (HsQualTy { hst_ctxt = L cx hs_ctxt, hst_body = hs_ty })
      | Just (hs_ctxt1, hs_ctxt_last) <- snocView hs_ctxt
      , L lx (HsWildCardTy wc) <- ignoreParens hs_ctxt_last
      = do { (hs_ctxt1', fvs1) <- mapFvRn (rn_top_constraint env) hs_ctxt1
           ; wc' <- setSrcSpan lx $
                    do { checkExtraConstraintWildCard env wc
                       ; rnAnonWildCard wc }
           ; let hs_ctxt' = hs_ctxt1' ++ [L lx (HsWildCardTy wc')]
           ; (hs_ty', fvs2) <- rnLHsTyKi env hs_ty
           ; return (HsQualTy { hst_ctxt = L cx hs_ctxt', hst_body = hs_ty' }
                    , fvs1 `plusFV` fvs2) }

      | otherwise
      = do { (hs_ctxt', fvs1) <- mapFvRn (rn_top_constraint env) hs_ctxt
           ; (hs_ty', fvs2)   <- rnLHsTyKi env hs_ty
           ; return (HsQualTy { hst_ctxt = L cx hs_ctxt', hst_body = hs_ty' }
                    , fvs1 `plusFV` fvs2) }

    rn_ty env hs_ty = rnHsTyKi env hs_ty

    rn_top_constraint env = rnLHsTyKi (env { rtke_what = RnTopConstraint })
178

179

180
checkExtraConstraintWildCard :: RnTyKiEnv -> HsWildCardInfo GhcPs
181 182 183 184 185 186 187
                             -> RnM ()
-- Rename the extra-constraint spot in a type signature
--    (blah, _) => type
-- Check that extra-constraints are allowed at all, and
-- if so that it's an anonymous wildcard
checkExtraConstraintWildCard env wc
  = checkWildCard env mb_bad
188
  where
189 190 191 192 193
    mb_bad | not (extraConstraintWildCardsAllowed env)
           = Just (text "Extra-constraint wildcard" <+> quotes (ppr wc)
                   <+> text "not allowed")
           | otherwise
           = Nothing
194

195 196 197 198 199 200
extraConstraintWildCardsAllowed :: RnTyKiEnv -> Bool
extraConstraintWildCardsAllowed env
  = case rtke_ctxt env of
      TypeSigCtx {}       -> True
      ExprWithTySigCtx {} -> True
      _                   -> False
201

eir@cis.upenn.edu's avatar
eir@cis.upenn.edu committed
202
-- | Finds free type and kind variables in a type,
203 204 205 206
--     without duplicates, and
--     without variables that are already in scope in LocalRdrEnv
--   NB: this includes named wildcards, which look like perfectly
--       ordinary type variables at this point
207
extractFilteredRdrTyVars :: LHsType GhcPs -> RnM FreeKiTyVars
eir@cis.upenn.edu's avatar
eir@cis.upenn.edu committed
208
extractFilteredRdrTyVars hs_ty
209 210 211 212 213 214 215 216 217
  = do { rdr_env <- getLocalRdrEnv
       ; filterInScope rdr_env <$> extractHsTyRdrTyVars hs_ty }

-- | When the NamedWildCards extension is enabled, partition_nwcs
-- removes type variables that start with an underscore from the
-- FreeKiTyVars in the argument and returns them in a separate list.
-- When the extension is disabled, the function returns the argument
-- and empty list.  See Note [Renaming named wild cards]
partition_nwcs :: FreeKiTyVars -> RnM (FreeKiTyVars, [Located RdrName])
218
partition_nwcs free_vars@(FKTV { fktv_tys = tys })
219 220 221
  = do { wildcards_enabled <- fmap (xopt LangExt.NamedWildCards) getDynFlags
       ; let (nwcs, no_nwcs) | wildcards_enabled = partition is_wildcard tys
                             | otherwise         = ([], tys)
222
             free_vars' = free_vars { fktv_tys = no_nwcs }
223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241
       ; return (free_vars', nwcs) }
  where
     is_wildcard :: Located RdrName -> Bool
     is_wildcard rdr = startsWithUnderscore (rdrNameOcc (unLoc rdr))

{- Note [Renaming named wild cards]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Identifiers starting with an underscore are always parsed as type variables.
It is only here in the renamer that we give the special treatment.
See Note [The wildcard story for types] in HsTypes.

It's easy!  When we collect the implicitly bound type variables, ready
to bring them into scope, and NamedWildCards is on, we partition the
variables into the ones that start with an underscore (the named
wildcards) and the rest. Then we just add them to the hswc_wcs field
of the HsWildCardBndrs structure, and we are done.


*********************************************************
242 243 244 245 246
*                                                       *
           HsSigtype (i.e. no wildcards)
*                                                       *
****************************************************** -}

247 248
rnHsSigType :: HsDocContext -> LHsSigType GhcPs
            -> RnM (LHsSigType GhcRn, FreeVars)
249 250 251
-- Used for source-language type signatures
-- that cannot have wildcards
rnHsSigType ctx (HsIB { hsib_body = hs_ty })
eir@cis.upenn.edu's avatar
eir@cis.upenn.edu committed
252
  = do { vars <- extractFilteredRdrTyVars hs_ty
253
       ; rnImplicitBndrs True vars hs_ty $ \ vars ->
254
    do { (body', fvs) <- rnLHsType ctx hs_ty
Richard Eisenberg's avatar
Richard Eisenberg committed
255
       ; return ( mk_implicit_bndrs vars body' fvs, fvs ) } }
256 257 258 259 260

rnImplicitBndrs :: Bool    -- True <=> no implicit quantification
                           --          if type is headed by a forall
                           -- E.g.  f :: forall a. a->b
                           -- Do not quantify over 'b' too.
261
                -> FreeKiTyVars
262
                -> LHsType GhcPs
263
                -> ([Name] -> RnM (a, FreeVars))
264
                -> RnM (a, FreeVars)
265 266 267
rnImplicitBndrs no_implicit_if_forall free_vars hs_ty@(L loc _) thing_inside
  = do { let real_tv_rdrs  -- Implicit quantification only if
                           -- there is no explicit forall
268 269
               | no_implicit_if_forall
               , L _ (HsForAllTy {}) <- hs_ty = []
270 271
               | otherwise                    = freeKiTyVarsTypeVars free_vars
             real_rdrs = freeKiTyVarsKindVars free_vars ++ real_tv_rdrs
272 273
       ; traceRn "rnSigType" (ppr hs_ty $$ ppr free_vars $$
                                        ppr real_rdrs)
Matthew Pickering's avatar
Matthew Pickering committed
274 275 276

       ; traceRn "" (text "rnSigType2" <+> ppr hs_ty $$ ppr free_vars $$
                                        ppr real_rdrs)
277 278 279
       ; vars <- mapM (newLocalBndrRn . L loc . unLoc) real_rdrs
       ; bindLocalNamesFV vars $
         thing_inside vars }
280

281
rnLHsInstType :: SDoc -> LHsSigType GhcPs -> RnM (LHsSigType GhcRn, FreeVars)
282 283 284 285 286 287 288
-- Rename the type in an instance or standalone deriving decl
-- The 'doc_str' is "an instance declaration" or "a VECTORISE pragma"
rnLHsInstType doc_str inst_ty
  | Just cls <- getLHsInstDeclClass_maybe inst_ty
  , isTcOcc (rdrNameOcc (unLoc cls))
         -- The guards check that the instance type looks like
         --   blah => C ty1 .. tyn
289
  = do { let full_doc = doc_str <+> text "for" <+> quotes (ppr cls)
290 291 292 293 294 295
       ; rnHsSigType (GenericCtx full_doc) inst_ty }

  | otherwise  -- The instance is malformed, but we'd still like
               -- to make progress rather than failing outright, so
               -- we report more errors.  So we rename it anyway.
  = do { addErrAt (getLoc (hsSigType inst_ty)) $
296
         text "Malformed instance:" <+> ppr inst_ty
297 298
       ; rnHsSigType (GenericCtx doc_str) inst_ty }

299
mk_implicit_bndrs :: [Name]  -- implicitly bound
Richard Eisenberg's avatar
Richard Eisenberg committed
300 301
                  -> a           -- payload
                  -> FreeVars    -- FreeVars of payload
302
                  -> HsImplicitBndrs GhcRn a
Richard Eisenberg's avatar
Richard Eisenberg committed
303 304 305 306 307
mk_implicit_bndrs vars body fvs
  = HsIB { hsib_vars = vars
         , hsib_body = body
         , hsib_closed = nameSetAll (not . isTyVarName) (vars `delFVs` fvs) }

308 309 310 311 312 313

{- ******************************************************
*                                                       *
           LHsType and HsType
*                                                       *
****************************************************** -}
314

Austin Seipp's avatar
Austin Seipp committed
315
{-
316 317 318
rnHsType is here because we call it from loadInstDecl, and I didn't
want a gratuitous knot.

319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334
Note [Context quantification]
-----------------------------
Variables in type signatures are implicitly quantified
when (1) they are in a type signature not beginning
with "forall" or (2) in any qualified type T => R.
We are phasing out (2) since it leads to inconsistencies
(Trac #4426):

data A = A (a -> a)           is an error
data A = A (Eq a => a -> a)   binds "a"
data A = A (Eq a => a -> b)   binds "a" and "b"
data A = A (() => a -> b)     binds "a" and "b"
f :: forall a. a -> b         is an error
f :: forall a. () => a -> b   is an error
f :: forall a. a -> (() => b) binds "a" and "b"

335 336
This situation is now considered to be an error. See rnHsTyKi for case
HsForAllTy Qualified.
337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365

Note [Dealing with *]
~~~~~~~~~~~~~~~~~~~~~
As a legacy from the days when types and kinds were different, we use
the type * to mean what we now call GHC.Types.Type. The problem is that
* should associate just like an identifier, *not* a symbol.
Running example: the user has written

  T (Int, Bool) b + c * d

At this point, we have a bunch of stretches of types

  [[T, (Int, Bool), b], [c], [d]]

these are the [[LHsType Name]] and a bunch of operators

  [GHC.TypeLits.+, GHC.Types.*]

Note that the * is GHC.Types.*. So, we want to rearrange to have

  [[T, (Int, Bool), b], [c, *, d]]

and

  [GHC.TypeLits.+]

as our lists. We can then do normal fixity resolution on these. The fixities
must come along for the ride just so that the list stays in sync with the
operators.
Simon Peyton Jones's avatar
Simon Peyton Jones committed
366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394

Note [QualTy in kinds]
~~~~~~~~~~~~~~~~~~~~~~
I was wondering whether QualTy could occur only at TypeLevel.  But no,
we can have a qualified type in a kind too. Here is an example:

  type family F a where
    F Bool = Nat
    F Nat  = Type

  type family G a where
    G Type = Type -> Type
    G ()   = Nat

  data X :: forall k1 k2. (F k1 ~ G k2) => k1 -> k2 -> Type where
    MkX :: X 'True '()

See that k1 becomes Bool and k2 becomes (), so the equality is
satisfied. If I write MkX :: X 'True 'False, compilation fails with a
suitable message:

  MkX :: X 'True '()
    • Couldn't match kind ‘G Bool’ with ‘Nat’
      Expected kind: G Bool
        Actual kind: F Bool

However: in a kind, the constraints in the QualTy must all be
equalities; or at least, any kinds with a class constraint are
uninhabited.
395
-}
396

397 398 399 400 401 402
data RnTyKiEnv
  = RTKE { rtke_ctxt  :: HsDocContext
         , rtke_level :: TypeOrKind  -- Am I renaming a type or a kind?
         , rtke_what  :: RnTyKiWhat  -- And within that what am I renaming?
         , rtke_nwcs  :: NameSet     -- These are the in-scope named wildcards
    }
403

404 405 406
data RnTyKiWhat = RnTypeBody
                | RnTopConstraint   -- Top-level context of HsSigWcTypes
                | RnConstraint      -- All other constraints
407

408 409 410
instance Outputable RnTyKiEnv where
  ppr (RTKE { rtke_level = lev, rtke_what = what
            , rtke_nwcs = wcs, rtke_ctxt = ctxt })
411
    = text "RTKE"
412 413
      <+> braces (sep [ ppr lev, ppr what, ppr wcs
                      , pprHsDocContext ctxt ])
414

415 416 417 418
instance Outputable RnTyKiWhat where
  ppr RnTypeBody      = text "RnTypeBody"
  ppr RnTopConstraint = text "RnTopConstraint"
  ppr RnConstraint    = text "RnConstraint"
419

420 421 422 423
mkTyKiEnv :: HsDocContext -> TypeOrKind -> RnTyKiWhat -> RnTyKiEnv
mkTyKiEnv cxt level what
 = RTKE { rtke_level = level, rtke_nwcs = emptyNameSet
        , rtke_what = what, rtke_ctxt = cxt }
424

425 426 427
isRnKindLevel :: RnTyKiEnv -> Bool
isRnKindLevel (RTKE { rtke_level = KindLevel }) = True
isRnKindLevel _                                 = False
dreixel's avatar
dreixel committed
428

429
--------------
430
rnLHsType  :: HsDocContext -> LHsType GhcPs -> RnM (LHsType GhcRn, FreeVars)
431
rnLHsType ctxt ty = rnLHsTyKi (mkTyKiEnv ctxt TypeLevel RnTypeBody) ty
432

433
rnLHsTypes :: HsDocContext -> [LHsType GhcPs] -> RnM ([LHsType GhcRn], FreeVars)
434 435
rnLHsTypes doc tys = mapFvRn (rnLHsType doc) tys

436
rnHsType  :: HsDocContext -> HsType GhcPs -> RnM (HsType GhcRn, FreeVars)
437
rnHsType ctxt ty = rnHsTyKi (mkTyKiEnv ctxt TypeLevel RnTypeBody) ty
438

439
rnLHsKind  :: HsDocContext -> LHsKind GhcPs -> RnM (LHsKind GhcRn, FreeVars)
440 441
rnLHsKind ctxt kind = rnLHsTyKi (mkTyKiEnv ctxt KindLevel RnTypeBody) kind

442
rnHsKind  :: HsDocContext -> HsKind GhcPs -> RnM (HsKind GhcRn, FreeVars)
443
rnHsKind ctxt kind = rnHsTyKi  (mkTyKiEnv ctxt KindLevel RnTypeBody) kind
dreixel's avatar
dreixel committed
444

445
--------------
446 447
rnTyKiContext :: RnTyKiEnv -> LHsContext GhcPs
              -> RnM (LHsContext GhcRn, FreeVars)
448
rnTyKiContext env (L loc cxt)
449
  = do { traceRn "rncontext" (ppr cxt)
450 451 452
       ; let env' = env { rtke_what = RnConstraint }
       ; (cxt', fvs) <- mapFvRn (rnLHsTyKi env') cxt
       ; return (L loc cxt', fvs) }
453

454 455
rnContext :: HsDocContext -> LHsContext GhcPs
          -> RnM (LHsContext GhcRn, FreeVars)
456
rnContext doc theta = rnTyKiContext (mkTyKiEnv doc TypeLevel RnConstraint) theta
457

458
--------------
459
rnLHsTyKi  :: RnTyKiEnv -> LHsType GhcPs -> RnM (LHsType GhcRn, FreeVars)
460 461 462 463
rnLHsTyKi env (L loc ty)
  = setSrcSpan loc $
    do { (ty', fvs) <- rnHsTyKi env ty
       ; return (L loc ty', fvs) }
464

465
rnHsTyKi :: RnTyKiEnv -> HsType GhcPs -> RnM (HsType GhcRn, FreeVars)
466 467 468

rnHsTyKi env ty@(HsForAllTy { hst_bndrs = tyvars, hst_body  = tau })
  = do { checkTypeInType env ty
eir@cis.upenn.edu's avatar
eir@cis.upenn.edu committed
469
       ; bindLHsTyVarBndrs (rtke_ctxt env) (Just $ inTypeDoc ty)
eir@cis.upenn.edu's avatar
eir@cis.upenn.edu committed
470
                           Nothing [] tyvars $ \ _ tyvars' _ _ ->
471
    do { (tau',  fvs) <- rnLHsTyKi env tau
472
       ; return ( HsForAllTy { hst_bndrs = tyvars', hst_body =  tau' }
473
                , fvs) } }
474

Simon Peyton Jones's avatar
Simon Peyton Jones committed
475 476
rnHsTyKi env ty@(HsQualTy { hst_ctxt = lctxt, hst_body = tau })
  = do { checkTypeInType env ty  -- See Note [QualTy in kinds]
477 478
       ; (ctxt', fvs1) <- rnTyKiContext env lctxt
       ; (tau',  fvs2) <- rnLHsTyKi env tau
479 480 481
       ; return (HsQualTy { hst_ctxt = ctxt', hst_body =  tau' }
                , fvs1 `plusFV` fvs2) }

Alan Zimmerman's avatar
Alan Zimmerman committed
482
rnHsTyKi env (HsTyVar ip (L loc rdr_name))
483
  = do { name <- rnTyVar env rdr_name
Alan Zimmerman's avatar
Alan Zimmerman committed
484
       ; return (HsTyVar ip (L loc name), unitFV name) }
485

486
rnHsTyKi env ty@(HsOpTy ty1 l_op ty2)
487
  = setSrcSpan (getLoc l_op) $
488
    do  { (l_op', fvs1) <- rnHsTyOp env ty l_op
489
        ; fix   <- lookupTyFixityRn l_op'
490 491
        ; (ty1', fvs2) <- rnLHsTyKi env ty1
        ; (ty2', fvs3) <- rnLHsTyKi env ty2
492 493 494
        ; res_ty <- mkHsOpTyRn (\t1 t2 -> HsOpTy t1 l_op' t2)
                               (unLoc l_op') fix ty1' ty2'
        ; return (res_ty, plusFVs [fvs1, fvs2, fvs3]) }
495

496 497
rnHsTyKi env (HsParTy ty)
  = do { (ty', fvs) <- rnLHsTyKi env ty
498
       ; return (HsParTy ty', fvs) }
499

500 501
rnHsTyKi env (HsBangTy b ty)
  = do { (ty', fvs) <- rnLHsTyKi env ty
502
       ; return (HsBangTy b ty', fvs) }
503

504 505 506 507
rnHsTyKi env ty@(HsRecTy flds)
  = do { let ctxt = rtke_ctxt env
       ; fls          <- get_fields ctxt
       ; (flds', fvs) <- rnConDeclFields ctxt fls flds
508
       ; return (HsRecTy flds', fvs) }
509 510 511 512
  where
    get_fields (ConDeclCtx names)
      = concatMapM (lookupConstructorFields . unLoc) names
    get_fields _
513
      = do { addErr (hang (text "Record syntax is illegal here:")
514 515 516 517 518
                                   2 (ppr ty))
           ; return [] }

rnHsTyKi env (HsFunTy ty1 ty2)
  = do { (ty1', fvs1) <- rnLHsTyKi env ty1
gmainlan@microsoft.com's avatar
gmainlan@microsoft.com committed
519
        -- Might find a for-all as the arg of a function type
520
       ; (ty2', fvs2) <- rnLHsTyKi env ty2
gmainlan@microsoft.com's avatar
gmainlan@microsoft.com committed
521 522
        -- Or as the result.  This happens when reading Prelude.hi
        -- when we find return :: forall m. Monad m -> forall a. a -> m a
523

gmainlan@microsoft.com's avatar
gmainlan@microsoft.com committed
524
        -- Check for fixity rearrangements
525
       ; res_ty <- mkHsOpTyRn HsFunTy funTyConName funTyFixity ty1' ty2'
526
       ; return (res_ty, fvs1 `plusFV` fvs2) }
dreixel's avatar
dreixel committed
527

528
rnHsTyKi env listTy@(HsListTy ty)
529
  = do { data_kinds <- xoptM LangExt.DataKinds
530 531 532
       ; when (not data_kinds && isRnKindLevel env)
              (addErr (dataKindsErr env listTy))
       ; (ty', fvs) <- rnLHsTyKi env ty
533
       ; return (HsListTy ty', fvs) }
534

535 536
rnHsTyKi env t@(HsKindSig ty k)
  = do { checkTypeInType env t
537
       ; kind_sigs_ok <- xoptM LangExt.KindSignatures
538 539 540
       ; unless kind_sigs_ok (badKindSigErr (rtke_ctxt env) ty)
       ; (ty', fvs1) <- rnLHsTyKi env ty
       ; (k', fvs2)  <- rnLHsTyKi (env { rtke_level = KindLevel }) k
541
       ; return (HsKindSig ty' k', fvs1 `plusFV` fvs2) }
542

543 544 545
rnHsTyKi env t@(HsPArrTy ty)
  = do { notInKinds env t
       ; (ty', fvs) <- rnLHsTyKi env ty
546
       ; return (HsPArrTy ty', fvs) }
chak's avatar
chak committed
547

548 549
-- Unboxed tuples are allowed to have poly-typed arguments.  These
-- sometimes crop up as a result of CPR worker-wrappering dictionaries.
550
rnHsTyKi env tupleTy@(HsTupleTy tup_con tys)
551
  = do { data_kinds <- xoptM LangExt.DataKinds
552 553 554
       ; when (not data_kinds && isRnKindLevel env)
              (addErr (dataKindsErr env tupleTy))
       ; (tys', fvs) <- mapFvRn (rnLHsTyKi env) tys
555 556
       ; return (HsTupleTy tup_con tys', fvs) }

557 558 559 560 561 562 563
rnHsTyKi env sumTy@(HsSumTy tys)
  = do { data_kinds <- xoptM LangExt.DataKinds
       ; when (not data_kinds && isRnKindLevel env)
              (addErr (dataKindsErr env sumTy))
       ; (tys', fvs) <- mapFvRn (rnLHsTyKi env) tys
       ; return (HsSumTy tys', fvs) }

564
-- Ensure that a type-level integer is nonnegative (#8306, #8412)
565
rnHsTyKi env tyLit@(HsTyLit t)
566
  = do { data_kinds <- xoptM LangExt.DataKinds
567
       ; unless data_kinds (addErr (dataKindsErr env tyLit))
568
       ; when (negLit t) (addErr negLitErr)
569
       ; checkTypeInType env tyLit
570
       ; return (HsTyLit t, emptyFVs) }
571
  where
Alan Zimmerman's avatar
Alan Zimmerman committed
572 573
    negLit (HsStrTy _ _) = False
    negLit (HsNumTy _ i) = i < 0
574
    negLitErr = text "Illegal literal in type (type literals must not be negative):" <+> ppr tyLit
575

576
rnHsTyKi env overall_ty@(HsAppsTy tys)
577 578 579 580
  = do { -- Step 1: Break up the HsAppsTy into symbols and non-symbol regions
         let (non_syms, syms) = splitHsAppsTy tys

             -- Step 2: rename the pieces
581 582
       ; (syms1, fvs1)      <- mapFvRn (rnHsTyOp env overall_ty) syms
       ; (non_syms1, fvs2)  <- (mapFvRn . mapFvRn) (rnLHsTyKi env) non_syms
583 584 585 586 587 588 589 590 591 592 593 594 595 596

             -- Step 3: deal with *. See Note [Dealing with *]
       ; let (non_syms2, syms2) = deal_with_star [] [] non_syms1 syms1

             -- Step 4: collapse the non-symbol regions with HsAppTy
       ; non_syms3 <- mapM deal_with_non_syms non_syms2

             -- Step 5: assemble the pieces, using mkHsOpTyRn
       ; L _ res_ty <- build_res_ty non_syms3 syms2

        -- all done. Phew.
       ; return (res_ty, fvs1 `plusFV` fvs2) }
  where
    -- See Note [Dealing with *]
597 598 599
    deal_with_star :: [[LHsType GhcRn]] -> [Located Name]
                   -> [[LHsType GhcRn]] -> [Located Name]
                   -> ([[LHsType GhcRn]], [Located Name])
600 601 602 603
    deal_with_star acc1 acc2
                   (non_syms1 : non_syms2 : non_syms) (L loc star : ops)
      | star `hasKey` starKindTyConKey || star `hasKey` unicodeStarKindTyConKey
      = deal_with_star acc1 acc2
Alan Zimmerman's avatar
Alan Zimmerman committed
604 605
                       ((non_syms1 ++ L loc (HsTyVar NotPromoted (L loc star))
                            : non_syms2) : non_syms)
606 607 608 609 610 611 612 613
                       ops
    deal_with_star acc1 acc2 (non_syms1 : non_syms) (op1 : ops)
      = deal_with_star (non_syms1 : acc1) (op1 : acc2) non_syms ops
    deal_with_star acc1 acc2 [non_syms] []
      = (reverse (non_syms : acc1), reverse acc2)
    deal_with_star _ _ _ _
      = pprPanic "deal_with_star" (ppr overall_ty)

614
    -- collapse [LHsType GhcRn] to LHsType GhcRn by making applications
615
    -- monadic only for failure
616
    deal_with_non_syms :: [LHsType GhcRn] -> RnM (LHsType GhcRn)
617 618 619 620
    deal_with_non_syms (non_sym : non_syms) = return $ mkHsAppTys non_sym non_syms
    deal_with_non_syms []                   = failWith (emptyNonSymsErr overall_ty)

    -- assemble a right-biased OpTy for use in mkHsOpTyRn
621
    build_res_ty :: [LHsType GhcRn] -> [Located Name] -> RnM (LHsType GhcRn)
622 623 624 625 626 627 628 629 630 631 632
    build_res_ty (arg1 : args) (op1 : ops)
      = do { rhs <- build_res_ty args ops
           ; fix <- lookupTyFixityRn op1
           ; res <-
               mkHsOpTyRn (\t1 t2 -> HsOpTy t1 op1 t2) (unLoc op1) fix arg1 rhs
           ; let loc = combineSrcSpans (getLoc arg1) (getLoc rhs)
           ; return (L loc res)
           }
    build_res_ty [arg] [] = return arg
    build_res_ty _ _ = pprPanic "build_op_ty" (ppr overall_ty)

633 634 635
rnHsTyKi env (HsAppTy ty1 ty2)
  = do { (ty1', fvs1) <- rnLHsTyKi env ty1
       ; (ty2', fvs2) <- rnLHsTyKi env ty2
636 637
       ; return (HsAppTy ty1' ty2', fvs1 `plusFV` fvs2) }

638 639 640
rnHsTyKi env t@(HsIParamTy n ty)
  = do { notInKinds env t
       ; (ty', fvs) <- rnLHsTyKi env ty
641
       ; return (HsIParamTy n ty', fvs) }
642

643 644 645 646
rnHsTyKi env t@(HsEqTy ty1 ty2)
  = do { checkTypeInType env t
       ; (ty1', fvs1) <- rnLHsTyKi env ty1
       ; (ty2', fvs2) <- rnLHsTyKi env ty2
647
       ; return (HsEqTy ty1' ty2', fvs1 `plusFV` fvs2) }
648

649
rnHsTyKi _ (HsSpliceTy sp k)
650
  = rnSpliceType sp k
simonpj@microsoft.com's avatar
simonpj@microsoft.com committed
651

652 653
rnHsTyKi env (HsDocTy ty haddock_doc)
  = do { (ty', fvs) <- rnLHsTyKi env ty
654 655
       ; haddock_doc' <- rnLHsDoc haddock_doc
       ; return (HsDocTy ty' haddock_doc', fvs) }
656

657
rnHsTyKi _ (HsCoreTy ty)
658
  = return (HsCoreTy ty, emptyFVs)
gmainlan@microsoft.com's avatar
gmainlan@microsoft.com committed
659
    -- The emptyFVs probably isn't quite right
660 661
    -- but I don't think it matters

Alan Zimmerman's avatar
Alan Zimmerman committed
662
rnHsTyKi env ty@(HsExplicitListTy ip k tys)
663
  = do { checkTypeInType env ty
664
       ; data_kinds <- xoptM LangExt.DataKinds
665 666
       ; unless data_kinds (addErr (dataKindsErr env ty))
       ; (tys', fvs) <- mapFvRn (rnLHsTyKi env) tys
Alan Zimmerman's avatar
Alan Zimmerman committed
667
       ; return (HsExplicitListTy ip k tys', fvs) }
668

669 670
rnHsTyKi env ty@(HsExplicitTupleTy kis tys)
  = do { checkTypeInType env ty
671
       ; data_kinds <- xoptM LangExt.DataKinds
672 673
       ; unless data_kinds (addErr (dataKindsErr env ty))
       ; (tys', fvs) <- mapFvRn (rnLHsTyKi env) tys
674 675
       ; return (HsExplicitTupleTy kis tys', fvs) }

676 677 678
rnHsTyKi env (HsWildCardTy wc)
  = do { checkAnonWildCard env wc
       ; wc' <- rnAnonWildCard wc
679
       ; return (HsWildCardTy wc', emptyFVs) }
680
         -- emptyFVs: this occurrence does not refer to a
681 682
         --           user-written binding site, so don't treat
         --           it as a free variable
thomasw's avatar
thomasw committed
683

684
--------------
685 686 687 688 689 690 691
rnTyVar :: RnTyKiEnv -> RdrName -> RnM Name
rnTyVar env rdr_name
  = do { name <- if   isRnKindLevel env
                 then lookupKindOccRn rdr_name
                 else lookupTypeOccRn rdr_name
       ; checkNamedWildCard env name
       ; return name }
692

693
rnLTyVar :: Located RdrName -> RnM (Located Name)
694
-- Called externally; does not deal with wildards
695 696 697
rnLTyVar (L loc rdr_name)
  = do { tyvar <- lookupTypeOccRn rdr_name
       ; return (L loc tyvar) }
698

699 700
--------------
rnHsTyOp :: Outputable a
701 702
         => RnTyKiEnv -> a -> Located RdrName
         -> RnM (Located Name, FreeVars)
703
rnHsTyOp env overall_ty (L loc op)
704
  = do { ops_ok <- xoptM LangExt.TypeOperators
705
       ; op' <- rnTyVar env op
706 707 708 709 710 711 712 713
       ; unless (ops_ok
                 || op' == starKindTyConName
                 || op' == unicodeStarKindTyConName
                 || op' `hasKey` eqTyConKey) $
           addErr (opTyErr op overall_ty)
       ; let l_op' = L loc op'
       ; return (l_op', unitFV op') }

simonpj@microsoft.com's avatar
simonpj@microsoft.com committed
714
--------------
715 716
notAllowed :: SDoc -> SDoc
notAllowed doc
717
  = text "Wildcard" <+> quotes doc <+> ptext (sLit "not allowed")
718 719 720

checkWildCard :: RnTyKiEnv -> Maybe SDoc -> RnM ()
checkWildCard env (Just doc)
721
  = addErr $ vcat [doc, nest 2 (text "in" <+> pprHsDocContext (rtke_ctxt env))]
722 723
checkWildCard _ Nothing
  = return ()
724

725
checkAnonWildCard :: RnTyKiEnv -> HsWildCardInfo GhcPs -> RnM ()
Gabor Greif's avatar
Gabor Greif committed
726
-- Report an error if an anonymous wildcard is illegal here
727 728 729 730 731 732 733 734 735 736 737 738
checkAnonWildCard env wc
  = checkWildCard env mb_bad
  where
    mb_bad :: Maybe SDoc
    mb_bad | not (wildCardsAllowed env)
           = Just (notAllowed (ppr wc))
           | otherwise
           = case rtke_what env of
               RnTypeBody      -> Nothing
               RnConstraint    -> Just constraint_msg
               RnTopConstraint -> Just constraint_msg

739
    constraint_msg = hang (notAllowed (ppr wc) <+> text "in a constraint")
740
                        2 hint_msg
741 742
    hint_msg = vcat [ text "except as the last top-level constraint of a type signature"
                    , nest 2 (text "e.g  f :: (Eq a, _) => blah") ]
743 744 745 746 747 748 749 750 751 752 753 754 755 756 757

checkNamedWildCard :: RnTyKiEnv -> Name -> RnM ()
-- Report an error if a named wildcard is illegal here
checkNamedWildCard env name
  = checkWildCard env mb_bad
  where
    mb_bad | not (name `elemNameSet` rtke_nwcs env)
           = Nothing  -- Not a wildcard
           | not (wildCardsAllowed env)
           = Just (notAllowed (ppr name))
           | otherwise
           = case rtke_what env of
               RnTypeBody      -> Nothing   -- Allowed
               RnTopConstraint -> Nothing   -- Allowed
               RnConstraint    -> Just constraint_msg
758
    constraint_msg = notAllowed (ppr name) <+> text "in a constraint"
759 760

wildCardsAllowed :: RnTyKiEnv -> Bool
761
-- ^ In what contexts are wildcards permitted
762 763
wildCardsAllowed env
   = case rtke_ctxt env of
764 765 766 767 768 769 770 771
       TypeSigCtx {}       -> True
       TypBrCtx {}         -> True   -- Template Haskell quoted type
       SpliceTypeCtx {}    -> True   -- Result of a Template Haskell splice
       ExprWithTySigCtx {} -> True
       PatCtx {}           -> True
       RuleCtx {}          -> True
       FamPatCtx {}        -> True   -- Not named wildcards though
       GHCiCtx {}          -> True
eir@cis.upenn.edu's avatar
eir@cis.upenn.edu committed
772
       HsTypeCtx {}        -> True
773 774
       _                   -> False

775
rnAnonWildCard :: HsWildCardInfo GhcPs -> RnM (HsWildCardInfo GhcRn)
776
rnAnonWildCard (AnonWildCard _)
777 778 779 780 781
  = do { loc <- getSrcSpanM
       ; uniq <- newUnique
       ; let name = mkInternalName uniq (mkTyVarOcc "_") loc
       ; return (AnonWildCard (L loc name)) }

782 783 784
---------------
-- | Ensures either that we're in a type or that -XTypeInType is set
checkTypeInType :: Outputable ty
785
                => RnTyKiEnv
786 787
                -> ty      -- ^ type
                -> RnM ()
788 789
checkTypeInType env ty
  | isRnKindLevel env
790
  = do { type_in_type <- xoptM LangExt.TypeInType
791 792 793 794 795 796
       ; unless type_in_type $
         addErr (text "Illegal kind:" <+> ppr ty $$
                 text "Did you mean to enable TypeInType?") }
checkTypeInType _ _ = return ()

notInKinds :: Outputable ty
797
           => RnTyKiEnv
798 799
           -> ty
           -> RnM ()
800 801
notInKinds env ty
  | isRnKindLevel env
802 803 804
  = addErr (text "Illegal kind (even with TypeInType enabled):" <+> ppr ty)
notInKinds _ _ = return ()

805 806 807 808 809 810
{- *****************************************************
*                                                      *
          Binding type variables
*                                                      *
***************************************************** -}

811
bindSigTyVarsFV :: [Name]
gmainlan@microsoft.com's avatar
gmainlan@microsoft.com committed
812 813
                -> RnM (a, FreeVars)
                -> RnM (a, FreeVars)
814 815 816 817
-- Used just before renaming the defn of a function
-- with a separate type signature, to bring its tyvars into scope
-- With no -XScopedTypeVariables, this is a no-op
bindSigTyVarsFV tvs thing_inside
818
  = do  { scoped_tyvars <- xoptM LangExt.ScopedTypeVariables
gmainlan@microsoft.com's avatar
gmainlan@microsoft.com committed
819 820 821 822
        ; if not scoped_tyvars then
                thing_inside
          else
                bindLocalNamesFV tvs thing_inside }
823

824 825 826 827 828 829 830 831 832 833 834
-- | Simply bring a bunch of RdrNames into scope. No checking for
-- validity, at all. The binding location is taken from the location
-- on each name.
bindLRdrNames :: [Located RdrName]
              -> ([Name] -> RnM (a, FreeVars))
              -> RnM (a, FreeVars)
bindLRdrNames rdrs thing_inside
  = do { var_names <- mapM (newTyVarNameRn Nothing) rdrs
       ; bindLocalNamesFV var_names $
         thing_inside var_names }

835
---------------
836 837
bindHsQTyVars :: forall a b.
                 HsDocContext
eir@cis.upenn.edu's avatar
eir@cis.upenn.edu committed
838 839
              -> Maybe SDoc         -- if we are to check for unused tvs,
                                    -- a phrase like "in the type ..."
840
              -> Maybe a                 -- Just _  => an associated type decl
841
              -> [Located RdrName]    -- Kind variables from scope, in l-to-r
842
                                         -- order, but not from ...
843 844
              -> (LHsQTyVars GhcPs)       -- ... these user-written tyvars
              -> (LHsQTyVars GhcRn -> NameSet -> RnM (b, FreeVars))
eir@cis.upenn.edu's avatar
eir@cis.upenn.edu committed
845 846 847
                  -- also returns all names used in kind signatures, for the
                  -- TypeInType clause of Note [Complete user-supplied kind
                  -- signatures] in HsDecls
848
              -> RnM (b, FreeVars)
gmainlan@microsoft.com's avatar
gmainlan@microsoft.com committed
849 850
-- (a) Bring kind variables into scope
--     both (i)  passed in (kv_bndrs)
Simon Peyton Jones's avatar
Simon Peyton Jones committed
851
--     and  (ii) mentioned in the kinds of tv_bndrs
852
-- (b) Bring type variables into scope
eir@cis.upenn.edu's avatar
eir@cis.upenn.edu committed
853 854 855
bindHsQTyVars doc mb_in_doc mb_assoc kv_bndrs tv_bndrs thing_inside
  = do { bindLHsTyVarBndrs doc mb_in_doc
                           mb_assoc kv_bndrs (hsQTvExplicit tv_bndrs) $
eir@cis.upenn.edu's avatar
eir@cis.upenn.edu committed
856
         \ rn_kvs rn_bndrs dep_var_set all_dep_vars ->
857
         thing_inside (HsQTvs { hsq_implicit = rn_kvs
eir@cis.upenn.edu's avatar
eir@cis.upenn.edu committed
858
                              , hsq_explicit = rn_bndrs
eir@cis.upenn.edu's avatar
eir@cis.upenn.edu committed
859
                              , hsq_dependent = dep_var_set }) all_dep_vars }
860 861 862

bindLHsTyVarBndrs :: forall a b.
                     HsDocContext
eir@cis.upenn.edu's avatar
eir@cis.upenn.edu committed
863 864
                  -> Maybe SDoc         -- if we are to check for unused tvs,
                                        -- a phrase like "in the type ..."
865
                  -> Maybe a            -- Just _  => an associated type decl
866 867 868
                  -> [Located RdrName] -- Unbound kind variables from scope,
                                          -- in l-to-r order, but not from ...
                  -> [LHsTyVarBndr GhcPs]  -- ... these user-written tyvars