{-
(c) The University of Glasgow 2006
(c) The AQUA Project, Glasgow University, 1996-1998


TcTyClsDecls: Typecheck type and class declarations
-}

{-# LANGUAGE CPP, TupleSections, MultiWayIf #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE ViewPatterns #-}

module TcTyClsDecls (
        tcTyAndClassDecls,

        -- Functions used by TcInstDcls to check
        -- data/type family instance declarations
        kcConDecl, tcConDecls, dataDeclChecks, checkValidTyCon,
        tcFamTyPats, tcTyFamInstEqn,
        tcAddTyFamInstCtxt, tcMkDataFamInstCtxt, tcAddDataFamInstCtxt,
        unravelFamInstPats, addConsistencyConstraints,
        wrongKindOfFamily
    ) where

#include "HsVersions.h"

import GhcPrelude

import HsSyn
import HscTypes
import BuildTyCl
import TcRnMonad
import TcEnv
import TcValidity
import TcHsSyn
import TcTyDecls
import TcClassDcl
import {-# SOURCE #-} TcInstDcls( tcInstDecls1 )
import TcDeriv (DerivInfo)
import TcHsType
import ClsInst( AssocInstInfo(..) )
import Inst( tcInstTyBinders )
import TcMType
import TysWiredIn ( unitTy )
import TcType
import RnEnv( lookupConstructorFields )
import FamInst
import FamInstEnv
import Coercion
import Type
import TyCoRep   -- for checkValidRoles
import Class
import CoAxiom
import TyCon
import DataCon
import Id
import Var
import VarEnv
import VarSet
import Module
import Name
import NameSet
import NameEnv
import Outputable
import Maybes
import Unify
import Util
import SrcLoc
import ListSetOps
import DynFlags
import Unique
import ConLike( ConLike(..) )
import BasicTypes
import qualified GHC.LanguageExtensions as LangExt

import Control.Monad
import Data.List
import Data.List.NonEmpty ( NonEmpty(..) )
import qualified Data.Set as Set


{-
************************************************************************
*                                                                      *
\subsection{Type checking for type and class declarations}
*                                                                      *
************************************************************************

Note [Grouping of type and class declarations]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
tcTyAndClassDecls is called on a list of `TyClGroup`s. Each group is a strongly
connected component of mutually dependent types and classes. We kind check and
type check each group separately to enhance kind polymorphism. Take the
following example:

  type Id a = a
  data X = X (Id Int)

If we were to kind check the two declarations together, we would give Id the
kind * -> *, since we apply it to an Int in the definition of X. But we can do
better than that, since Id really is kind polymorphic, and should get kind
forall (k::*). k -> k. Since it does not depend on anything else, it can be
kind-checked by itself, hence getting the most general kind. We then kind check
X, which works fine because we then know the polymorphic kind of Id, and simply
instantiate k to *.

Note [Check role annotations in a second pass]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Role inference potentially depends on the types of all of the datacons declared
in a mutually recursive group. The validity of a role annotation, in turn,
depends on the result of role inference. Because the types of datacons might
be ill-formed (see #7175 and Note [Checking GADT return types]) we must check
*all* the tycons in a group for validity before checking *any* of the roles.
Thus, we take two passes over the resulting tycons, first checking for general
validity and then checking for valid role annotations.
-}

tcTyAndClassDecls :: [TyClGroup GhcRn]      -- Mutually-recursive groups in
                                            -- dependency order
                  -> TcM ( TcGblEnv         -- Input env extended by types and
                                            -- classes
                                            -- and their implicit Ids,DataCons
                         , [InstInfo GhcRn] -- Source-code instance decls info
                         , [DerivInfo]      -- data family deriving info
                         )
-- Fails if there are any errors
tcTyAndClassDecls :: [TyClGroup GhcRn] -> TcM (TcGblEnv, [InstInfo GhcRn], [DerivInfo])
tcTyAndClassDecls tyclds_s :: [TyClGroup GhcRn]
tyclds_s
  -- The code recovers internally, but if anything gave rise to
  -- an error we'd better stop now, to avoid a cascade
  -- Type check each group in dependency order folding the global env
  = TcM (TcGblEnv, [InstInfo GhcRn], [DerivInfo])
-> TcM (TcGblEnv, [InstInfo GhcRn], [DerivInfo])
forall r. TcM r -> TcM r
checkNoErrs (TcM (TcGblEnv, [InstInfo GhcRn], [DerivInfo])
 -> TcM (TcGblEnv, [InstInfo GhcRn], [DerivInfo]))
-> TcM (TcGblEnv, [InstInfo GhcRn], [DerivInfo])
-> TcM (TcGblEnv, [InstInfo GhcRn], [DerivInfo])
forall a b. (a -> b) -> a -> b
$ [InstInfo GhcRn]
-> [DerivInfo]
-> [TyClGroup GhcRn]
-> TcM (TcGblEnv, [InstInfo GhcRn], [DerivInfo])
fold_env [] [] [TyClGroup GhcRn]
tyclds_s
  where
    fold_env :: [InstInfo GhcRn]
             -> [DerivInfo]
             -> [TyClGroup GhcRn]
             -> TcM (TcGblEnv, [InstInfo GhcRn], [DerivInfo])
    fold_env :: [InstInfo GhcRn]
-> [DerivInfo]
-> [TyClGroup GhcRn]
-> TcM (TcGblEnv, [InstInfo GhcRn], [DerivInfo])
fold_env inst_info :: [InstInfo GhcRn]
inst_info deriv_info :: [DerivInfo]
deriv_info []
      = do { TcGblEnv
gbl_env <- TcRnIf TcGblEnv TcLclEnv TcGblEnv
forall gbl lcl. TcRnIf gbl lcl gbl
getGblEnv
           ; (TcGblEnv, [InstInfo GhcRn], [DerivInfo])
-> TcM (TcGblEnv, [InstInfo GhcRn], [DerivInfo])
forall (m :: * -> *) a. Monad m => a -> m a
return (TcGblEnv
gbl_env, [InstInfo GhcRn]
inst_info, [DerivInfo]
deriv_info) }
    fold_env inst_info :: [InstInfo GhcRn]
inst_info deriv_info :: [DerivInfo]
deriv_info (tyclds :: TyClGroup GhcRn
tyclds:tyclds_s :: [TyClGroup GhcRn]
tyclds_s)
      = do { (tcg_env :: TcGblEnv
tcg_env, inst_info' :: [InstInfo GhcRn]
inst_info', deriv_info' :: [DerivInfo]
deriv_info') <- TyClGroup GhcRn -> TcM (TcGblEnv, [InstInfo GhcRn], [DerivInfo])
tcTyClGroup TyClGroup GhcRn
tyclds
           ; TcGblEnv
-> TcM (TcGblEnv, [InstInfo GhcRn], [DerivInfo])
-> TcM (TcGblEnv, [InstInfo GhcRn], [DerivInfo])
forall gbl lcl a. gbl -> TcRnIf gbl lcl a -> TcRnIf gbl lcl a
setGblEnv TcGblEnv
tcg_env (TcM (TcGblEnv, [InstInfo GhcRn], [DerivInfo])
 -> TcM (TcGblEnv, [InstInfo GhcRn], [DerivInfo]))
-> TcM (TcGblEnv, [InstInfo GhcRn], [DerivInfo])
-> TcM (TcGblEnv, [InstInfo GhcRn], [DerivInfo])
forall a b. (a -> b) -> a -> b
$
               -- remaining groups are typechecked in the extended global env.
             [InstInfo GhcRn]
-> [DerivInfo]
-> [TyClGroup GhcRn]
-> TcM (TcGblEnv, [InstInfo GhcRn], [DerivInfo])
fold_env ([InstInfo GhcRn]
inst_info' [InstInfo GhcRn] -> [InstInfo GhcRn] -> [InstInfo GhcRn]
forall a. [a] -> [a] -> [a]
++ [InstInfo GhcRn]
inst_info)
                      ([DerivInfo]
deriv_info' [DerivInfo] -> [DerivInfo] -> [DerivInfo]
forall a. [a] -> [a] -> [a]
++ [DerivInfo]
deriv_info)
                      [TyClGroup GhcRn]
tyclds_s }

tcTyClGroup :: TyClGroup GhcRn
            -> TcM (TcGblEnv, [InstInfo GhcRn], [DerivInfo])
-- Typecheck one strongly-connected component of type, class, and instance decls
-- See Note [TyClGroups and dependency analysis] in HsDecls
tcTyClGroup :: TyClGroup GhcRn -> TcM (TcGblEnv, [InstInfo GhcRn], [DerivInfo])
tcTyClGroup (TyClGroup { group_tyclds :: forall pass. TyClGroup pass -> [LTyClDecl pass]
group_tyclds = [LTyClDecl GhcRn]
tyclds
                       , group_roles :: forall pass. TyClGroup pass -> [LRoleAnnotDecl pass]
group_roles  = [LRoleAnnotDecl GhcRn]
roles
                       , group_instds :: forall pass. TyClGroup pass -> [LInstDecl pass]
group_instds = [LInstDecl GhcRn]
instds })
  = do { let role_annots :: RoleAnnotEnv
role_annots = [LRoleAnnotDecl GhcRn] -> RoleAnnotEnv
mkRoleAnnotEnv [LRoleAnnotDecl GhcRn]
roles

           -- Step 1: Typecheck the type/class declarations
       ; String -> SDoc -> TcRn ()
traceTc "---- tcTyClGroup ---- {" SDoc
empty
       ; String -> SDoc -> TcRn ()
traceTc "Decls for" ([Name] -> SDoc
forall a. Outputable a => a -> SDoc
ppr ((LTyClDecl GhcRn -> Name) -> [LTyClDecl GhcRn] -> [Name]
forall a b. (a -> b) -> [a] -> [b]
map (TyClDecl GhcRn -> Name
forall pass. TyClDecl pass -> IdP pass
tcdName (TyClDecl GhcRn -> Name)
-> (LTyClDecl GhcRn -> TyClDecl GhcRn) -> LTyClDecl GhcRn -> Name
forall b c a. (b -> c) -> (a -> b) -> a -> c
. LTyClDecl GhcRn -> TyClDecl GhcRn
forall a. HasSrcSpan a => a -> SrcSpanLess a
unLoc) [LTyClDecl GhcRn]
tyclds))
       ; [TyCon]
tyclss <- [LTyClDecl GhcRn] -> RoleAnnotEnv -> TcM [TyCon]
tcTyClDecls [LTyClDecl GhcRn]
tyclds RoleAnnotEnv
role_annots

           -- Step 1.5: Make sure we don't have any type synonym cycles
       ; String -> SDoc -> TcRn ()
traceTc "Starting synonym cycle check" ([TyCon] -> SDoc
forall a. Outputable a => a -> SDoc
ppr [TyCon]
tyclss)
       ; UnitId
this_uid <- (DynFlags -> UnitId)
-> IOEnv (Env TcGblEnv TcLclEnv) DynFlags
-> IOEnv (Env TcGblEnv TcLclEnv) UnitId
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
fmap DynFlags -> UnitId
thisPackage IOEnv (Env TcGblEnv TcLclEnv) DynFlags
forall (m :: * -> *). HasDynFlags m => m DynFlags
getDynFlags
       ; UnitId -> [TyCon] -> [LTyClDecl GhcRn] -> TcRn ()
checkSynCycles UnitId
this_uid [TyCon]
tyclss [LTyClDecl GhcRn]
tyclds
       ; String -> SDoc -> TcRn ()
traceTc "Done synonym cycle check" ([TyCon] -> SDoc
forall a. Outputable a => a -> SDoc
ppr [TyCon]
tyclss)

           -- Step 2: Perform the validity check on those types/classes
           -- We can do this now because we are done with the recursive knot
           -- Do it before Step 3 (adding implicit things) because the latter
           -- expects well-formed TyCons
       ; String -> SDoc -> TcRn ()
traceTc "Starting validity check" ([TyCon] -> SDoc
forall a. Outputable a => a -> SDoc
ppr [TyCon]
tyclss)
       ; [TyCon]
tyclss <- (TyCon -> TcM [TyCon]) -> [TyCon] -> TcM [TyCon]
forall (m :: * -> *) a b. Monad m => (a -> m [b]) -> [a] -> m [b]
concatMapM TyCon -> TcM [TyCon]
checkValidTyCl [TyCon]
tyclss
       ; String -> SDoc -> TcRn ()
traceTc "Done validity check" ([TyCon] -> SDoc
forall a. Outputable a => a -> SDoc
ppr [TyCon]
tyclss)
       ; (TyCon -> TcRn ()) -> [TyCon] -> TcRn ()
forall (t :: * -> *) (m :: * -> *) a b.
(Foldable t, Monad m) =>
(a -> m b) -> t a -> m ()
mapM_ (TcRn () -> TcRn () -> TcRn ()
forall r. TcRn r -> TcRn r -> TcRn r
recoverM (() -> TcRn ()
forall (m :: * -> *) a. Monad m => a -> m a
return ()) (TcRn () -> TcRn ()) -> (TyCon -> TcRn ()) -> TyCon -> TcRn ()
forall b c a. (b -> c) -> (a -> b) -> a -> c
. RoleAnnotEnv -> TyCon -> TcRn ()
checkValidRoleAnnots RoleAnnotEnv
role_annots) [TyCon]
tyclss
           -- See Note [Check role annotations in a second pass]

       ; String -> SDoc -> TcRn ()
traceTc "---- end tcTyClGroup ---- }" SDoc
empty

           -- Step 3: Add the implicit things;
           -- we want them in the environment because
           -- they may be mentioned in interface files
       ; TcGblEnv
gbl_env <- [TyCon] -> TcRnIf TcGblEnv TcLclEnv TcGblEnv
addTyConsToGblEnv [TyCon]
tyclss

           -- Step 4: check instance declarations
       ; TcGblEnv
-> TcM (TcGblEnv, [InstInfo GhcRn], [DerivInfo])
-> TcM (TcGblEnv, [InstInfo GhcRn], [DerivInfo])
forall gbl lcl a. gbl -> TcRnIf gbl lcl a -> TcRnIf gbl lcl a
setGblEnv TcGblEnv
gbl_env (TcM (TcGblEnv, [InstInfo GhcRn], [DerivInfo])
 -> TcM (TcGblEnv, [InstInfo GhcRn], [DerivInfo]))
-> TcM (TcGblEnv, [InstInfo GhcRn], [DerivInfo])
-> TcM (TcGblEnv, [InstInfo GhcRn], [DerivInfo])
forall a b. (a -> b) -> a -> b
$
         [LInstDecl GhcRn] -> TcM (TcGblEnv, [InstInfo GhcRn], [DerivInfo])
tcInstDecls1 [LInstDecl GhcRn]
instds }

tcTyClGroup (XTyClGroup _) = String -> TcM (TcGblEnv, [InstInfo GhcRn], [DerivInfo])
forall a. String -> a
panic "tcTyClGroup"

tcTyClDecls :: [LTyClDecl GhcRn] -> RoleAnnotEnv -> TcM [TyCon]
tcTyClDecls :: [LTyClDecl GhcRn] -> RoleAnnotEnv -> TcM [TyCon]
tcTyClDecls tyclds :: [LTyClDecl GhcRn]
tyclds role_annots :: RoleAnnotEnv
role_annots
  = NameEnv TcTyThing -> TcM [TyCon] -> TcM [TyCon]
forall r. NameEnv TcTyThing -> TcM r -> TcM r
tcExtendKindEnv NameEnv TcTyThing
promotion_err_env (TcM [TyCon] -> TcM [TyCon]) -> TcM [TyCon] -> TcM [TyCon]
forall a b. (a -> b) -> a -> b
$   --- See Note [Type environment evolution]
    do {    -- Step 1: kind-check this group and returns the final
            -- (possibly-polymorphic) kind of each TyCon and Class
            -- See Note [Kind checking for type and class decls]
         [TyCon]
tc_tycons <- [LTyClDecl GhcRn] -> TcM [TyCon]
kcTyClGroup [LTyClDecl GhcRn]
tyclds
       ; String -> SDoc -> TcRn ()
traceTc "tcTyAndCl generalized kinds" ([SDoc] -> SDoc
vcat ((TyCon -> SDoc) -> [TyCon] -> [SDoc]
forall a b. (a -> b) -> [a] -> [b]
map TyCon -> SDoc
ppr_tc_tycon [TyCon]
tc_tycons))

            -- Step 2: type-check all groups together, returning
            -- the final TyCons and Classes
            --
            -- NB: We have to be careful here to NOT eagerly unfold
            -- type synonyms, as we have not tested for type synonym
            -- loops yet and could fall into a black hole.
       ; ([TyCon] -> TcM [TyCon]) -> TcM [TyCon]
forall a env. (a -> IOEnv env a) -> IOEnv env a
fixM (([TyCon] -> TcM [TyCon]) -> TcM [TyCon])
-> ([TyCon] -> TcM [TyCon]) -> TcM [TyCon]
forall a b. (a -> b) -> a -> b
$ \ ~[TyCon]
rec_tyclss -> do
           { TcGblEnv
tcg_env <- TcRnIf TcGblEnv TcLclEnv TcGblEnv
forall gbl lcl. TcRnIf gbl lcl gbl
getGblEnv
           ; let roles :: Name -> [Role]
roles = HscSource -> RoleAnnotEnv -> [TyCon] -> Name -> [Role]
inferRoles (TcGblEnv -> HscSource
tcg_src TcGblEnv
tcg_env) RoleAnnotEnv
role_annots [TyCon]
rec_tyclss

                 -- Populate environment with knot-tied ATyCon for TyCons
                 -- NB: if the decls mention any ill-staged data cons
                 -- (see Note [Recursion and promoting data constructors])
                 -- we will have failed already in kcTyClGroup, so no worries here
           ; [(Name, TyThing)] -> TcM [TyCon] -> TcM [TyCon]
forall r. [(Name, TyThing)] -> TcM r -> TcM r
tcExtendRecEnv ([TyCon] -> [TyCon] -> [(Name, TyThing)]
zipRecTyClss [TyCon]
tc_tycons [TyCon]
rec_tyclss) (TcM [TyCon] -> TcM [TyCon]) -> TcM [TyCon] -> TcM [TyCon]
forall a b. (a -> b) -> a -> b
$

                 -- Also extend the local type envt with bindings giving
                 -- a TcTyCon for each each knot-tied TyCon or Class
                 -- See Note [Type checking recursive type and class declarations]
                 -- and Note [Type environment evolution]
             [TyCon] -> TcM [TyCon] -> TcM [TyCon]
forall a. [TyCon] -> TcM a -> TcM a
tcExtendKindEnvWithTyCons [TyCon]
tc_tycons (TcM [TyCon] -> TcM [TyCon]) -> TcM [TyCon] -> TcM [TyCon]
forall a b. (a -> b) -> a -> b
$

                 -- Kind and type check declarations for this group
               (LTyClDecl GhcRn -> IOEnv (Env TcGblEnv TcLclEnv) TyCon)
-> [LTyClDecl GhcRn] -> TcM [TyCon]
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
mapM ((Name -> [Role])
-> LTyClDecl GhcRn -> IOEnv (Env TcGblEnv TcLclEnv) TyCon
tcTyClDecl Name -> [Role]
roles) [LTyClDecl GhcRn]
tyclds
           } }
  where
    promotion_err_env :: NameEnv TcTyThing
promotion_err_env = [LTyClDecl GhcRn] -> NameEnv TcTyThing
mkPromotionErrorEnv [LTyClDecl GhcRn]
tyclds
    ppr_tc_tycon :: TyCon -> SDoc
ppr_tc_tycon tc :: TyCon
tc = SDoc -> SDoc
parens ([SDoc] -> SDoc
sep [ Name -> SDoc
forall a. Outputable a => a -> SDoc
ppr (TyCon -> Name
tyConName TyCon
tc) SDoc -> SDoc -> SDoc
<> SDoc
comma
                                  , [TyConBinder] -> SDoc
forall a. Outputable a => a -> SDoc
ppr (TyCon -> [TyConBinder]
tyConBinders TyCon
tc) SDoc -> SDoc -> SDoc
<> SDoc
comma
                                  , Kind -> SDoc
forall a. Outputable a => a -> SDoc
ppr (TyCon -> Kind
tyConResKind TyCon
tc)
                                  , Bool -> SDoc
forall a. Outputable a => a -> SDoc
ppr (TyCon -> Bool
isTcTyCon TyCon
tc) ])

zipRecTyClss :: [TcTyCon]
             -> [TyCon]           -- Knot-tied
             -> [(Name,TyThing)]
-- Build a name-TyThing mapping for the TyCons bound by decls
-- being careful not to look at the knot-tied [TyThing]
-- The TyThings in the result list must have a visible ATyCon,
-- because typechecking types (in, say, tcTyClDecl) looks at
-- this outer constructor
zipRecTyClss :: [TyCon] -> [TyCon] -> [(Name, TyThing)]
zipRecTyClss tc_tycons :: [TyCon]
tc_tycons rec_tycons :: [TyCon]
rec_tycons
  = [ (Name
name, TyCon -> TyThing
ATyCon (Name -> TyCon
get Name
name)) | TyCon
tc_tycon <- [TyCon]
tc_tycons, let name :: Name
name = TyCon -> Name
forall a. NamedThing a => a -> Name
getName TyCon
tc_tycon ]
  where
    rec_tc_env :: NameEnv TyCon
    rec_tc_env :: NameEnv TyCon
rec_tc_env = (TyCon -> NameEnv TyCon -> NameEnv TyCon)
-> NameEnv TyCon -> [TyCon] -> NameEnv TyCon
forall (t :: * -> *) a b.
Foldable t =>
(a -> b -> b) -> b -> t a -> b
foldr TyCon -> NameEnv TyCon -> NameEnv TyCon
add_tc NameEnv TyCon
forall a. NameEnv a
emptyNameEnv [TyCon]
rec_tycons

    add_tc :: TyCon -> NameEnv TyCon -> NameEnv TyCon
    add_tc :: TyCon -> NameEnv TyCon -> NameEnv TyCon
add_tc tc :: TyCon
tc env :: NameEnv TyCon
env = (TyCon -> NameEnv TyCon -> NameEnv TyCon)
-> NameEnv TyCon -> [TyCon] -> NameEnv TyCon
forall (t :: * -> *) a b.
Foldable t =>
(a -> b -> b) -> b -> t a -> b
foldr TyCon -> NameEnv TyCon -> NameEnv TyCon
add_one_tc NameEnv TyCon
env (TyCon
tc TyCon -> [TyCon] -> [TyCon]
forall a. a -> [a] -> [a]
: TyCon -> [TyCon]
tyConATs TyCon
tc)

    add_one_tc :: TyCon -> NameEnv TyCon -> NameEnv TyCon
    add_one_tc :: TyCon -> NameEnv TyCon -> NameEnv TyCon
add_one_tc tc :: TyCon
tc env :: NameEnv TyCon
env = NameEnv TyCon -> Name -> TyCon -> NameEnv TyCon
forall a. NameEnv a -> Name -> a -> NameEnv a
extendNameEnv NameEnv TyCon
env (TyCon -> Name
tyConName TyCon
tc) TyCon
tc

    get :: Name -> TyCon
get name :: Name
name = case NameEnv TyCon -> Name -> Maybe TyCon
forall a. NameEnv a -> Name -> Maybe a
lookupNameEnv NameEnv TyCon
rec_tc_env Name
name of
                 Just tc :: TyCon
tc -> TyCon
tc
                 other :: Maybe TyCon
other   -> String -> SDoc -> TyCon
forall a. HasCallStack => String -> SDoc -> a
pprPanic "zipRecTyClss" (Name -> SDoc
forall a. Outputable a => a -> SDoc
ppr Name
name SDoc -> SDoc -> SDoc
<+> Maybe TyCon -> SDoc
forall a. Outputable a => a -> SDoc
ppr Maybe TyCon
other)

{-
************************************************************************
*                                                                      *
                Kind checking
*                                                                      *
************************************************************************

Note [Kind checking for type and class decls]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Kind checking is done thus:

   1. Make up a kind variable for each parameter of the declarations,
      and extend the kind environment (which is in the TcLclEnv)

   2. Kind check the declarations

We need to kind check all types in the mutually recursive group
before we know the kind of the type variables.  For example:

  class C a where
     op :: D b => a -> b -> b

  class D c where
     bop :: (Monad c) => ...

Here, the kind of the locally-polymorphic type variable "b"
depends on *all the uses of class D*.  For example, the use of
Monad c in bop's type signature means that D must have kind Type->Type.

Note: we don't treat type synonyms specially (we used to, in the past);
in particular, even if we have a type synonym cycle, we still kind check
it normally, and test for cycles later (checkSynCycles).  The reason
we can get away with this is because we have more systematic TYPE r
inference, which means that we can do unification between kinds that
aren't lifted (this historically was not true.)

The downside of not directly reading off the kinds off the RHS of
type synonyms in topological order is that we don't transparently
support making synonyms of types with higher-rank kinds.  But
you can always specify a CUSK directly to make this work out.
See tc269 for an example.

Note [Skip decls with CUSKs in kcLTyClDecl]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Consider

    data T (a :: *) = MkT (S a)   -- Has CUSK
    data S a = MkS (T Int) (S a)  -- No CUSK

Via getInitialKinds we get
  T :: * -> *
  S :: kappa -> *

Then we call kcTyClDecl on each decl in the group, to constrain the
kind unification variables.  BUT we /skip/ the RHS of any decl with
a CUSK.  Here we skip the RHS of T, so we eventually get
  S :: forall k. k -> *

This gets us more polymorphism than we would otherwise get, similar
(but implemented strangely differently from) the treatment of type
signatures in value declarations.

Open type families
~~~~~~~~~~~~~~~~~~
This treatment of type synonyms only applies to Haskell 98-style synonyms.
General type functions can be recursive, and hence, appear in `alg_decls'.

The kind of an open type family is solely determinded by its kind signature;
hence, only kind signatures participate in the construction of the initial
kind environment (as constructed by `getInitialKind'). In fact, we ignore
instances of families altogether in the following. However, we need to include
the kinds of *associated* families into the construction of the initial kind
environment. (This is handled by `allDecls').

See also Note [Kind checking recursive type and class declarations]

Note [How TcTyCons work]
~~~~~~~~~~~~~~~~~~~~~~~~
TcTyCons are used for two distinct purposes

1.  When recovering from a type error in a type declaration,
    we want to put the erroneous TyCon in the environment in a
    way that won't lead to more errors.  We use a TcTyCon for this;
    see makeRecoveryTyCon.

2.  When checking a type/class declaration (in module TcTyClsDecls), we come
    upon knowledge of the eventual tycon in bits and pieces.

      S1) First, we use getInitialKinds to look over the user-provided
          kind signature of a tycon (including, for example, the number
          of parameters written to the tycon) to get an initial shape of
          the tycon's kind.  We record that shape in a TcTyCon.

          For CUSK tycons, the TcTyCon has the final, generalised kind.
          For non-CUSK tycons, the TcTyCon has as its tyConBinders only
          the explicit arguments given -- no kind variables, etc.

      S2) Then, using these initial kinds, we kind-check the body of the
          tycon (class methods, data constructors, etc.), filling in the
          metavariables in the tycon's initial kind.

      S3) We then generalize to get the (non-CUSK) tycon's final, fixed
          kind. Finally, once this has happened for all tycons in a
          mutually recursive group, we can desugar the lot.

    For convenience, we store partially-known tycons in TcTyCons, which
    might store meta-variables. These TcTyCons are stored in the local
    environment in TcTyClsDecls, until the real full TyCons can be created
    during desugaring. A desugared program should never have a TcTyCon.

3.  In a TcTyCon, everything is zonked after the kind-checking pass (S2).

4.  tyConScopedTyVars.  A challenging piece in all of this is that we
    end up taking three separate passes over every declaration:
      - one in getInitialKind (this pass look only at the head, not the body)
      - one in kcTyClDecls (to kind-check the body)
      - a final one in tcTyClDecls (to desugar)

    In the latter two passes, we need to connect the user-written type
    variables in an LHsQTyVars with the variables in the tycon's
    inferred kind. Because the tycon might not have a CUSK, this
    matching up is, in general, quite hard to do.  (Look through the
    git history between Dec 2015 and Apr 2016 for
    TcHsType.splitTelescopeTvs!)

    Instead of trying, we just store the list of type variables to
    bring into scope, in the tyConScopedTyVars field of the TcTyCon.
    These tyvars are brought into scope in TcHsType.bindTyClTyVars.

    In a TcTyCon, why is tyConScopedTyVars :: [(Name,TcTyVar)] rather
    than just [TcTyVar]?  Consider these mutually-recursive decls
       data T (a :: k1) b = MkT (S a b)
       data S (c :: k2) d = MkS (T c d)
    We start with k1 bound to kappa1, and k2 to kappa2; so initially
    in the (Name,TcTyVar) pairs the Name is that of the TcTyVar. But
    then kappa1 and kappa2 get unified; so after the zonking in
    'generalise' in 'kcTyClGroup' the Name and TcTyVar may differ.

See also Note [Type checking recursive type and class declarations].

Note [Type environment evolution]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
As we typecheck a group of declarations the type environment evolves.
Consider for example:
  data B (a :: Type) = MkB (Proxy 'MkB)

We do the following steps:

  1. Start of tcTyClDecls: use mkPromotionErrorEnv to initialise the
     type env with promotion errors
            B   :-> TyConPE
            MkB :-> DataConPE

  2. kcTyCLGruup
      - Do getInitialKinds, which will signal a promotion
        error if B is used in any of the kinds needed to initialse
        B's kind (e.g. (a :: Type)) here

      - Extend the type env with these initial kinds (monomorphic for
        decls that lack a CUSK)
            B :-> TcTyCon <initial kind>
        (thereby overriding the B :-> TyConPE binding)
        and do kcLTyClDecl on each decl to get equality constraints on
        all those inital kinds

      - Generalise the inital kind, making a poly-kinded TcTyCon

  3. Back in tcTyDecls, extend the envt with bindings of the poly-kinded
     TcTyCons, again overriding the promotion-error bindings.

     But note that the data constructor promotion errors are still in place
     so that (in our example) a use of MkB will sitll be signalled as
     an error.

  4. Typecheck the decls.

  5. In tcTyClGroup, extend the envt with bindings for TyCon and DataCons


Note [Missed opportunity to retain higher-rank kinds]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In 'kcTyClGroup', there is a missed opportunity to make kind
inference work in a few more cases.  The idea is analogous
to Note [Single function non-recursive binding special-case]:

     * If we have an SCC with a single decl, which is non-recursive,
       instead of creating a unification variable representing the
       kind of the decl and unifying it with the rhs, we can just
       read the type directly of the rhs.

     * Furthermore, we can update our SCC analysis to ignore
       dependencies on declarations which have CUSKs: we don't
       have to kind-check these all at once, since we can use
       the CUSK to initialize the kind environment.

Unfortunately this requires reworking a bit of the code in
'kcLTyClDecl' so I've decided to punt unless someone shouts about it.

Note [Don't process associated types in kcLHsQTyVars]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Previously, we processed associated types in the thing_inside in kcLHsQTyVars,
but this was wrong -- we want to do ATs sepearately.
The consequence for not doing it this way is #15142:

  class ListTuple (tuple :: Type) (as :: [(k, Type)]) where
    type ListToTuple as :: Type

We assign k a kind kappa[1]. When checking the tuple (k, Type), we try to unify
kappa ~ Type, but this gets deferred because we bumped the TcLevel as we bring
`tuple` into scope. Thus, when we check ListToTuple, kappa[1] still hasn't
unified with Type. And then, when we generalize the kind of ListToTuple (which
indeed has a CUSK, according to the rules), we skolemize the free metavariable
kappa. Note that we wouldn't skolemize kappa when generalizing the kind of ListTuple,
because the solveEqualities in kcLHsQTyVars is at TcLevel 1 and so kappa[1]
will unify with Type.

Bottom line: as associated types should have no effect on a CUSK enclosing class,
we move processing them to a separate action, run after the outer kind has
been generalized.

-}

kcTyClGroup :: [LTyClDecl GhcRn] -> TcM [TcTyCon]

-- Kind check this group, kind generalize, and return the resulting local env
-- This binds the TyCons and Classes of the group, but not the DataCons
-- See Note [Kind checking for type and class decls]
-- and Note [Inferring kinds for type declarations]
kcTyClGroup :: [LTyClDecl GhcRn] -> TcM [TyCon]
kcTyClGroup decls :: [LTyClDecl GhcRn]
decls
  = do  { Module
mod <- IOEnv (Env TcGblEnv TcLclEnv) Module
forall (m :: * -> *). HasModule m => m Module
getModule
        ; String -> SDoc -> TcRn ()
traceTc "---- kcTyClGroup ---- {"
                  (String -> SDoc
text "module" SDoc -> SDoc -> SDoc
<+> Module -> SDoc
forall a. Outputable a => a -> SDoc
ppr Module
mod SDoc -> SDoc -> SDoc
$$ [SDoc] -> SDoc
vcat ((LTyClDecl GhcRn -> SDoc) -> [LTyClDecl GhcRn] -> [SDoc]
forall a b. (a -> b) -> [a] -> [b]
map LTyClDecl GhcRn -> SDoc
forall a. Outputable a => a -> SDoc
ppr [LTyClDecl GhcRn]
decls))

          -- Kind checking;
          --    1. Bind kind variables for decls
          --    2. Kind-check decls
          --    3. Generalise the inferred kinds
          -- See Note [Kind checking for type and class decls]

        ; let (cusk_decls :: [LTyClDecl GhcRn]
cusk_decls, no_cusk_decls :: [LTyClDecl GhcRn]
no_cusk_decls)
                 = (LTyClDecl GhcRn -> Bool)
-> [LTyClDecl GhcRn] -> ([LTyClDecl GhcRn], [LTyClDecl GhcRn])
forall a. (a -> Bool) -> [a] -> ([a], [a])
partition (TyClDecl GhcRn -> Bool
hsDeclHasCusk (TyClDecl GhcRn -> Bool)
-> (LTyClDecl GhcRn -> TyClDecl GhcRn) -> LTyClDecl GhcRn -> Bool
forall b c a. (b -> c) -> (a -> b) -> a -> c
. LTyClDecl GhcRn -> TyClDecl GhcRn
forall a. HasSrcSpan a => a -> SrcSpanLess a
unLoc) [LTyClDecl GhcRn]
decls

        ; [TyCon]
poly_cusk_tcs <- Bool -> [LTyClDecl GhcRn] -> TcM [TyCon]
getInitialKinds Bool
True [LTyClDecl GhcRn]
cusk_decls

        ; [TyCon]
mono_tcs
            <- [TyCon] -> TcM [TyCon] -> TcM [TyCon]
forall a. [TyCon] -> TcM a -> TcM a
tcExtendKindEnvWithTyCons [TyCon]
poly_cusk_tcs (TcM [TyCon] -> TcM [TyCon]) -> TcM [TyCon] -> TcM [TyCon]
forall a b. (a -> b) -> a -> b
$
               TcM [TyCon] -> TcM [TyCon]
forall r. TcM r -> TcM r
pushTcLevelM_   (TcM [TyCon] -> TcM [TyCon]) -> TcM [TyCon] -> TcM [TyCon]
forall a b. (a -> b) -> a -> b
$  -- We are going to kind-generalise, so
                                  -- unification variables in here must
                                  -- be one level in
               TcM [TyCon] -> TcM [TyCon]
forall r. TcM r -> TcM r
solveEqualities (TcM [TyCon] -> TcM [TyCon]) -> TcM [TyCon] -> TcM [TyCon]
forall a b. (a -> b) -> a -> b
$
               do {  -- Step 1: Bind kind variables for all decls
                    [TyCon]
mono_tcs <- Bool -> [LTyClDecl GhcRn] -> TcM [TyCon]
getInitialKinds Bool
False [LTyClDecl GhcRn]
no_cusk_decls

                  ; String -> SDoc -> TcRn ()
traceTc "kcTyClGroup: initial kinds" (SDoc -> TcRn ()) -> SDoc -> TcRn ()
forall a b. (a -> b) -> a -> b
$
                    [TyCon] -> SDoc
ppr_tc_kinds [TyCon]
mono_tcs

                    -- Step 2: Set extended envt, kind-check the decls
                    -- NB: the environment extension overrides the tycon
                    --     promotion-errors bindings
                    --     See Note [Type environment evolution]
                  ; [TyCon] -> TcRn () -> TcRn ()
forall a. [TyCon] -> TcM a -> TcM a
tcExtendKindEnvWithTyCons [TyCon]
mono_tcs (TcRn () -> TcRn ()) -> TcRn () -> TcRn ()
forall a b. (a -> b) -> a -> b
$
                    (LTyClDecl GhcRn -> TcRn ()) -> [LTyClDecl GhcRn] -> TcRn ()
forall (t :: * -> *) (m :: * -> *) a b.
(Foldable t, Monad m) =>
(a -> m b) -> t a -> m ()
mapM_ LTyClDecl GhcRn -> TcRn ()
kcLTyClDecl [LTyClDecl GhcRn]
no_cusk_decls

                  ; [TyCon] -> TcM [TyCon]
forall (m :: * -> *) a. Monad m => a -> m a
return [TyCon]
mono_tcs }

        -- Step 3: generalisation
        -- Finally, go through each tycon and give it its final kind,
        -- with all the required, specified, and inferred variables
        -- in order.
        ; [TyCon]
poly_no_cusk_tcs <- (TyCon -> IOEnv (Env TcGblEnv TcLclEnv) TyCon)
-> [TyCon] -> TcM [TyCon]
forall a b. (a -> TcRn b) -> [a] -> TcRn [b]
mapAndReportM TyCon -> IOEnv (Env TcGblEnv TcLclEnv) TyCon
generaliseTcTyCon [TyCon]
mono_tcs

        ; let poly_tcs :: [TyCon]
poly_tcs = [TyCon]
poly_cusk_tcs [TyCon] -> [TyCon] -> [TyCon]
forall a. [a] -> [a] -> [a]
++ [TyCon]
poly_no_cusk_tcs
        ; String -> SDoc -> TcRn ()
traceTc "---- kcTyClGroup end ---- }" ([TyCon] -> SDoc
ppr_tc_kinds [TyCon]
poly_tcs)
        ; [TyCon] -> TcM [TyCon]
forall (m :: * -> *) a. Monad m => a -> m a
return [TyCon]
poly_tcs }

  where
    ppr_tc_kinds :: [TyCon] -> SDoc
ppr_tc_kinds tcs :: [TyCon]
tcs = [SDoc] -> SDoc
vcat ((TyCon -> SDoc) -> [TyCon] -> [SDoc]
forall a b. (a -> b) -> [a] -> [b]
map TyCon -> SDoc
pp_tc [TyCon]
tcs)
    pp_tc :: TyCon -> SDoc
pp_tc tc :: TyCon
tc = Name -> SDoc
forall a. Outputable a => a -> SDoc
ppr (TyCon -> Name
tyConName TyCon
tc) SDoc -> SDoc -> SDoc
<+> SDoc
dcolon SDoc -> SDoc -> SDoc
<+> Kind -> SDoc
forall a. Outputable a => a -> SDoc
ppr (TyCon -> Kind
tyConKind TyCon
tc)

generaliseTcTyCon :: TcTyCon -> TcM TcTyCon
generaliseTcTyCon :: TyCon -> IOEnv (Env TcGblEnv TcLclEnv) TyCon
generaliseTcTyCon tc :: TyCon
tc
  -- See Note [Required, Specified, and Inferred for types]
  = SrcSpan
-> IOEnv (Env TcGblEnv TcLclEnv) TyCon
-> IOEnv (Env TcGblEnv TcLclEnv) TyCon
forall a. SrcSpan -> TcRn a -> TcRn a
setSrcSpan (TyCon -> SrcSpan
forall a. NamedThing a => a -> SrcSpan
getSrcSpan TyCon
tc) (IOEnv (Env TcGblEnv TcLclEnv) TyCon
 -> IOEnv (Env TcGblEnv TcLclEnv) TyCon)
-> IOEnv (Env TcGblEnv TcLclEnv) TyCon
-> IOEnv (Env TcGblEnv TcLclEnv) TyCon
forall a b. (a -> b) -> a -> b
$
    TyCon
-> IOEnv (Env TcGblEnv TcLclEnv) TyCon
-> IOEnv (Env TcGblEnv TcLclEnv) TyCon
forall a. TyCon -> TcM a -> TcM a
addTyConCtxt TyCon
tc (IOEnv (Env TcGblEnv TcLclEnv) TyCon
 -> IOEnv (Env TcGblEnv TcLclEnv) TyCon)
-> IOEnv (Env TcGblEnv TcLclEnv) TyCon
-> IOEnv (Env TcGblEnv TcLclEnv) TyCon
forall a b. (a -> b) -> a -> b
$
    do { let tc_name :: Name
tc_name     = TyCon -> Name
tyConName TyCon
tc
             tc_flav :: TyConFlavour
tc_flav     = TyCon -> TyConFlavour
tyConFlavour TyCon
tc
             tc_res_kind :: Kind
tc_res_kind = TyCon -> Kind
tyConResKind TyCon
tc
             tc_tvs :: [TyVar]
tc_tvs      = TyCon -> [TyVar]
tyConTyVars  TyCon
tc
             user_tyvars :: SDoc
user_tyvars = TyCon -> SDoc
tcTyConUserTyVars TyCon
tc  -- ToDo: nuke

             (scoped_tv_names :: [Name]
scoped_tv_names, scoped_tvs :: [TyVar]
scoped_tvs) = [(Name, TyVar)] -> ([Name], [TyVar])
forall a b. [(a, b)] -> ([a], [b])
unzip (TyCon -> [(Name, TyVar)]
tcTyConScopedTyVars TyCon
tc)
             -- NB: scoped_tvs includes both specified and required (tc_tvs)
             -- ToDo: Is this a good idea?

       -- Step 1: find all the variables we want to quantify over,
       --         including Inferred, Specfied, and Required
       ; CandidatesQTvs
dvs <- [Kind] -> TcM CandidatesQTvs
candidateQTyVarsOfKinds ([Kind] -> TcM CandidatesQTvs) -> [Kind] -> TcM CandidatesQTvs
forall a b. (a -> b) -> a -> b
$
                (Kind
tc_res_kind Kind -> [Kind] -> [Kind]
forall a. a -> [a] -> [a]
: (TyVar -> Kind) -> [TyVar] -> [Kind]
forall a b. (a -> b) -> [a] -> [b]
map TyVar -> Kind
tyVarKind [TyVar]
scoped_tvs)
       ; [TyVar]
tc_tvs      <- (TyVar -> IOEnv (Env TcGblEnv TcLclEnv) TyVar)
-> [TyVar] -> IOEnv (Env TcGblEnv TcLclEnv) [TyVar]
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
mapM HasDebugCallStack => TyVar -> IOEnv (Env TcGblEnv TcLclEnv) TyVar
TyVar -> IOEnv (Env TcGblEnv TcLclEnv) TyVar
zonkTcTyVarToTyVar [TyVar]
tc_tvs
       ; let full_dvs :: CandidatesQTvs
full_dvs = CandidatesQTvs
dvs { dv_tvs :: DTyVarSet
dv_tvs = [TyVar] -> DTyVarSet
mkDVarSet [TyVar]
tc_tvs }

       -- Step 2: quantify, mainly meaning skolemise the free variables
       ; [TyVar]
qtkvs <- TcTyCoVarSet
-> CandidatesQTvs -> IOEnv (Env TcGblEnv TcLclEnv) [TyVar]
quantifyTyVars TcTyCoVarSet
emptyVarSet CandidatesQTvs
full_dvs
                  -- Returned 'qtkvs' are scope-sorted and skolemised

       -- Step 3: find the final identity of the Specified and Required tc_tvs
       -- (remember they all started as TyVarTvs).
       -- They have been skolemised by quantifyTyVars.
       ; [TyVar]
scoped_tvs  <- (TyVar -> IOEnv (Env TcGblEnv TcLclEnv) TyVar)
-> [TyVar] -> IOEnv (Env TcGblEnv TcLclEnv) [TyVar]
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
mapM HasDebugCallStack => TyVar -> IOEnv (Env TcGblEnv TcLclEnv) TyVar
TyVar -> IOEnv (Env TcGblEnv TcLclEnv) TyVar
zonkTcTyVarToTyVar [TyVar]
scoped_tvs
       ; [TyVar]
tc_tvs      <- (TyVar -> IOEnv (Env TcGblEnv TcLclEnv) TyVar)
-> [TyVar] -> IOEnv (Env TcGblEnv TcLclEnv) [TyVar]
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
mapM HasDebugCallStack => TyVar -> IOEnv (Env TcGblEnv TcLclEnv) TyVar
TyVar -> IOEnv (Env TcGblEnv TcLclEnv) TyVar
zonkTcTyVarToTyVar [TyVar]
tc_tvs
       ; Kind
tc_res_kind <- Kind -> TcM Kind
zonkTcType Kind
tc_res_kind

       ; String -> SDoc -> TcRn ()
traceTc "Generalise kind pre" (SDoc -> TcRn ()) -> SDoc -> TcRn ()
forall a b. (a -> b) -> a -> b
$
         [SDoc] -> SDoc
vcat [ String -> SDoc
text "tycon =" SDoc -> SDoc -> SDoc
<+> TyCon -> SDoc
forall a. Outputable a => a -> SDoc
ppr TyCon
tc
              , String -> SDoc
text "tc_tvs =" SDoc -> SDoc -> SDoc
<+> [TyVar] -> SDoc
pprTyVars [TyVar]
tc_tvs
              , String -> SDoc
text "scoped_tvs =" SDoc -> SDoc -> SDoc
<+> [TyVar] -> SDoc
pprTyVars [TyVar]
scoped_tvs ]

       -- Step 4: Find the Specified and Inferred variables
       -- First, delete the Required tc_tvs from qtkvs; then
       -- partition by whether they are scoped (if so, Specified)
       ; let qtkv_set :: TcTyCoVarSet
qtkv_set      = [TyVar] -> TcTyCoVarSet
mkVarSet [TyVar]
qtkvs
             tc_tv_set :: TcTyCoVarSet
tc_tv_set     = [TyVar] -> TcTyCoVarSet
mkVarSet [TyVar]
tc_tvs
             specified :: [TyVar]
specified     = [TyVar] -> [TyVar]
scopedSort ([TyVar] -> [TyVar]) -> [TyVar] -> [TyVar]
forall a b. (a -> b) -> a -> b
$
                             [ TyVar
tv | TyVar
tv <- [TyVar]
scoped_tvs
                                  , Bool -> Bool
not (TyVar
tv TyVar -> TcTyCoVarSet -> Bool
`elemVarSet` TcTyCoVarSet
tc_tv_set)
                                  , TyVar
tv TyVar -> TcTyCoVarSet -> Bool
`elemVarSet` TcTyCoVarSet
qtkv_set ]
                             -- NB: maintain the L-R order of scoped_tvs
             spec_req_set :: TcTyCoVarSet
spec_req_set  = [TyVar] -> TcTyCoVarSet
mkVarSet [TyVar]
specified TcTyCoVarSet -> TcTyCoVarSet -> TcTyCoVarSet
`unionVarSet` TcTyCoVarSet
tc_tv_set
             inferred :: [TyVar]
inferred      = (TyVar -> Bool) -> [TyVar] -> [TyVar]
forall a. (a -> Bool) -> [a] -> [a]
filterOut (TyVar -> TcTyCoVarSet -> Bool
`elemVarSet` TcTyCoVarSet
spec_req_set) [TyVar]
qtkvs

       -- Step 5: Make the TyConBinders.
             dep_fv_set :: TcTyCoVarSet
dep_fv_set     = CandidatesQTvs -> TcTyCoVarSet
candidateKindVars CandidatesQTvs
dvs
             inferred_tcbs :: [TyConBinder]
inferred_tcbs  = ArgFlag -> [TyVar] -> [TyConBinder]
mkNamedTyConBinders ArgFlag
Inferred [TyVar]
inferred
             specified_tcbs :: [TyConBinder]
specified_tcbs = ArgFlag -> [TyVar] -> [TyConBinder]
mkNamedTyConBinders ArgFlag
Specified [TyVar]
specified
             required_tcbs :: [TyConBinder]
required_tcbs  = (TyVar -> TyConBinder) -> [TyVar] -> [TyConBinder]
forall a b. (a -> b) -> [a] -> [b]
map (TcTyCoVarSet -> TyVar -> TyConBinder
mkRequiredTyConBinder TcTyCoVarSet
dep_fv_set) [TyVar]
tc_tvs

       -- Step 6: Assemble the final list.
             final_tcbs :: [TyConBinder]
final_tcbs = [[TyConBinder]] -> [TyConBinder]
forall (t :: * -> *) a. Foldable t => t [a] -> [a]
concat [ [TyConBinder]
inferred_tcbs
                                 , [TyConBinder]
specified_tcbs
                                 , [TyConBinder]
required_tcbs ]

             scoped_tv_pairs :: [(Name, TyVar)]
scoped_tv_pairs = [Name]
scoped_tv_names [Name] -> [TyVar] -> [(Name, TyVar)]
forall a b. [a] -> [b] -> [(a, b)]
`zip` [TyVar]
scoped_tvs

       -- Step 7: Make the result TcTyCon
             tycon :: TyCon
tycon = Name
-> SDoc
-> [TyConBinder]
-> Kind
-> [(Name, TyVar)]
-> Bool
-> TyConFlavour
-> TyCon
mkTcTyCon Name
tc_name SDoc
user_tyvars [TyConBinder]
final_tcbs Kind
tc_res_kind
                            [(Name, TyVar)]
scoped_tv_pairs
                            Bool
True {- it's generalised now -}
                            (TyCon -> TyConFlavour
tyConFlavour TyCon
tc)

       ; String -> SDoc -> TcRn ()
traceTc "Generalise kind" (SDoc -> TcRn ()) -> SDoc -> TcRn ()
forall a b. (a -> b) -> a -> b
$
         [SDoc] -> SDoc
vcat [ String -> SDoc
text "tycon =" SDoc -> SDoc -> SDoc
<+> TyCon -> SDoc
forall a. Outputable a => a -> SDoc
ppr TyCon
tc
              , String -> SDoc
text "tc_tvs =" SDoc -> SDoc -> SDoc
<+> [TyVar] -> SDoc
pprTyVars [TyVar]
tc_tvs
              , String -> SDoc
text "tc_res_kind =" SDoc -> SDoc -> SDoc
<+> Kind -> SDoc
forall a. Outputable a => a -> SDoc
ppr Kind
tc_res_kind
              , String -> SDoc
text "scoped_tvs =" SDoc -> SDoc -> SDoc
<+> [TyVar] -> SDoc
pprTyVars [TyVar]
scoped_tvs
              , String -> SDoc
text "inferred =" SDoc -> SDoc -> SDoc
<+> [TyVar] -> SDoc
pprTyVars [TyVar]
inferred
              , String -> SDoc
text "specified =" SDoc -> SDoc -> SDoc
<+> [TyVar] -> SDoc
pprTyVars [TyVar]
specified
              , String -> SDoc
text "required_tcbs =" SDoc -> SDoc -> SDoc
<+> [TyConBinder] -> SDoc
forall a. Outputable a => a -> SDoc
ppr [TyConBinder]
required_tcbs
              , String -> SDoc
text "final_tcbs =" SDoc -> SDoc -> SDoc
<+> [TyConBinder] -> SDoc
forall a. Outputable a => a -> SDoc
ppr [TyConBinder]
final_tcbs ]

       -- Step 8: check for floating kind vars
       -- See Note [Free-floating kind vars]
       -- They are easily identified by the fact that they
       -- have not been skolemised by quantifyTyVars
       ; let floating_specified :: [TyVar]
floating_specified = (TyVar -> Bool) -> [TyVar] -> [TyVar]
forall a. (a -> Bool) -> [a] -> [a]
filter TyVar -> Bool
isTyVarTyVar [TyVar]
scoped_tvs
       ; Name -> TyConFlavour -> [TyVar] -> [TyVar] -> TcRn ()
reportFloatingKvs Name
tc_name TyConFlavour
tc_flav
                           [TyVar]
scoped_tvs [TyVar]
floating_specified

       -- Step 9: Check for duplicates
       -- E.g. data SameKind (a::k) (b::k)
       --      data T (a::k1) (b::k2) = MkT (SameKind a b)
       -- Here k1 and k2 start as TyVarTvs, and get unified with each other
       ; ((Name, Name) -> TcRn ()) -> [(Name, Name)] -> TcRn ()
forall (t :: * -> *) (m :: * -> *) a b.
(Foldable t, Monad m) =>
(a -> m b) -> t a -> m ()
mapM_ (Name, Name) -> TcRn ()
forall a a.
(NamedThing a, Outputable a, Outputable a) =>
(a, a) -> TcRn ()
report_sig_tv_err ([(Name, TyVar)] -> [(Name, Name)]
findDupTyVarTvs [(Name, TyVar)]
scoped_tv_pairs)

       -- Step 10: Check for validity.
       -- We do this here because we're about to put the tycon into
       -- the environment, and we don't want anything malformed in the
       -- environment.
       ; TyCon -> TcRn ()
checkValidTelescope TyCon
tycon

       ; TyCon -> IOEnv (Env TcGblEnv TcLclEnv) TyCon
forall (m :: * -> *) a. Monad m => a -> m a
return TyCon
tycon }
  where
    report_sig_tv_err :: (a, a) -> TcRn ()
report_sig_tv_err (n1 :: a
n1, n2 :: a
n2)
      = SrcSpan -> TcRn () -> TcRn ()
forall a. SrcSpan -> TcRn a -> TcRn a
setSrcSpan (a -> SrcSpan
forall a. NamedThing a => a -> SrcSpan
getSrcSpan a
n2) (TcRn () -> TcRn ()) -> TcRn () -> TcRn ()
forall a b. (a -> b) -> a -> b
$
        SDoc -> TcRn ()
addErrTc (String -> SDoc
text "Couldn't match" SDoc -> SDoc -> SDoc
<+> SDoc -> SDoc
quotes (a -> SDoc
forall a. Outputable a => a -> SDoc
ppr a
n1)
                        SDoc -> SDoc -> SDoc
<+> String -> SDoc
text "with" SDoc -> SDoc -> SDoc
<+> SDoc -> SDoc
quotes (a -> SDoc
forall a. Outputable a => a -> SDoc
ppr a
n2))

{- Note [Required, Specified, and Inferred for types]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Each forall'd type variable in a type or kind is one of

  * Required: an argument must be provided at every call site

  * Specified: the argument can be inferred at call sites, but
    may be instantiated with visible type/kind application

  * Inferred: the must be inferred at call sites; it
    is unavailable for use with visible type/kind application.

Why have Inferred at all? Because we just can't make user-facing
promises about the ordering of some variables. These might swizzle
around even between minor released. By forbidding visible type
application, we ensure users aren't caught unawares.

Go read Note [VarBndrs, TyCoVarBinders, TyConBinders, and visibility] in TyCoRep.

The question for this Note is this:
   given a TyClDecl, how are its quantified type variables classified?
Much of the debate is memorialized in #15743.

Here is our design choice. When inferring the ordering of variables
for a TyCl declaration (that is, for those variables that he user
has not specified the order with an explicit `forall`), we use the
following order:

 1. Inferred variables
 2. Specified variables; in the left-to-right order in which
    the user wrote them, modified by scopedSort (see below)
    to put them in depdendency order.
 3. Required variables before a top-level ::
 4. All variables after a top-level ::

If this ordering does not make a valid telescope, we reject the definition.

Example:
  data SameKind :: k -> k -> *
  data Bad a (c :: Proxy b) (d :: Proxy a) (x :: SameKind b d)

For X:
  - a, c, d, x are Required; they are explicitly listed by the user
    as the positional arguments of Bad
  - b is Specified; it appears explicitly in a kind signature
  - k, the kind of a, is Inferred; it is not mentioned explicitly at all

Putting variables in the order Inferred, Specified, Required
gives us this telescope:
  Inferred:  k
  Specified: b : Proxy a
  Required : (a : k) (c : Proxy b) (d : Proxy a) (x : SameKind b d)

But this order is ill-scoped, because b's kind mentions a, which occurs
after b in the telescope. So we reject Bad.

Associated types
~~~~~~~~~~~~~~~~
For associated types everything above is determined by the
associated-type declaration alone, ignoring the class header.
Here is an example (Trac #15592)
  class C (a :: k) b where
    type F (x :: b a)

In the kind of C, 'k' is Specified.  But what about F?
In the kind of F,

 * Should k be Inferred or Specified?  It's Specified for C,
   but not mentioned in F's declaration.

 * In which order should the Specified variables a and b occur?
   It's clearly 'a' then 'b' in C's declaration, but the L-R ordering
   in F's declaration is 'b' then 'a'.

In both cases we make the choice by looking at F's declaration alone,
so it gets the kind
   F :: forall {k}. forall b a. b a -> Type

How it works
~~~~~~~~~~~~
These design choices are implemented by two completely different code
paths for

  * Declarations with a compulete user-specified kind signature (CUSK)
    Handed by the CUSK case of kcLHsQTyVars.

  * Declarations without a CUSK are handled by kcTyClDecl; see
    Note [Inferring kinds for type declarations].

Note that neither code path worries about point (4) above, as this
is nicely handled by not mangling the res_kind. (Mangling res_kinds is done
*after* all this stuff, in tcDataDefn's call to etaExpandAlgTyCon.)

We can tell Inferred apart from Specified by looking at the scoped
tyvars; Specified are always included there.

Design alternatives
~~~~~~~~~~~~~~~~~~~

* For associated types we considered putting the class variables
  before the local variables, in a nod to the treatment for class
  methods. But it got too compilicated; see Trac #15592, comment:21ff.

* We rigidly require the ordering above, even though we could be much more
  permissive. Relevant musings are at
  https://ghc.haskell.org/trac/ghc/ticket/15743#comment:7
  The bottom line conclusion is that, if the user wants a different ordering,
  then can specify it themselves, and it is better to be predictable and dumb
  than clever and capricious.

  I (Richard) conjecture we could be fully permissive, allowing all classes
  of variables to intermix. We would have to augment ScopedSort to refuse to
  reorder Required variables (or check that it wouldn't have). But this would
  allow more programs. See #15743 for examples. Interestingly, Idris seems
  to allow this intermixing. The intermixing would be fully specified, in that
  we can be sure that inference wouldn't change between versions. However,
  would users be able to predict it? That I cannot answer.

Test cases (and tickets) relevant to these design decisions
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  T15591*
  T15592*
  T15743*

Note [Inferring kinds for type declarations]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
This note deals with /inference/ for type declarations
that do not have a CUSK.  Consider
  data T (a :: k1) k2 (x :: k2) = MkT (S a k2 x)
  data S (b :: k3) k4 (y :: k4) = MkS (T b k4 y)

We do kind inference as follows:

* Step 1: Assign initial monomorophic kinds to S, T
          S :: kk1 -> * -> kk2 -> *
          T :: kk3 -> * -> kk4 -> *
  Here kk1 etc are TyVarTvs: that is, unification variables that
  are allowed to unify only with other type variables. See
  Note [Signature skolems] in TcType

* Step 2: Extend the environment with a TcTyCon for S and T, with
  these monomophic kinds.  Now kind-check the declarations, and solve
  the resulting equalities.  The goal here is to discover constraints
  on all these unification variables.

  Here we find that kk1 := kk3, and kk2 := kk4.

  This is why we can't use skolems for kk1 etc; they have to
  unify with each other.

* Step 3. Generalise each TyCon in turn (generaliseTcTyCon).
  We find the free variables of the kind, skolemise them,
  sort them out into Inferred/Required/Specified (see the above
  Note [Required, Specified, and Inferred for types]),
  and perform some validity checks.

  This makes the utterly-final TyConBinders for the TyCon

  All this is very similar at the level of terms: see TcBinds
  Note [Quantified variables in partial type signatures]

* Step 4.  Extend the type environment with a TcTyCon for S and T, now
  with their utterly-final polymorphic kinds (needed for recursive
  occurrences of S, T).  Now typecheck the declarations, and build the
  final AlgTyCOn for S and T resp.

The first three steps are in kcTyClGroup;
the fourth is in tcTyClDecls.

There are some wrinkles

* Do not default TyVarTvs.  We always want to kind-generalise over
  TyVarTvs, and /not/ default them to Type. By definition a TyVarTv is
  not allowed to unify with a type; it must stand for a type
  variable. Hence the check in TcSimplify.defaultTyVarTcS, and
  TcMType.defaultTyVar.  Here's another example (Trac #14555):
     data Exp :: [TYPE rep] -> TYPE rep -> Type where
        Lam :: Exp (a:xs) b -> Exp xs (a -> b)
  We want to kind-generalise over the 'rep' variable.
  Trac #14563 is another example.

* Duplicate type variables. Consider Trac #11203
    data SameKind :: k -> k -> *
    data Q (a :: k1) (b :: k2) c = MkQ (SameKind a b)
  Here we will unify k1 with k2, but this time doing so is an error,
  because k1 and k2 are bound in the same declaration.

  We spot this during validity checking (findDupTyVarTvs),
  in generaliseTcTyCon.

* Required arguments.  Even the Required arguments should be made
  into TyVarTvs, not skolems.  Consider
    data T k (a :: k)
  Here, k is a Required, dependent variable. For uniformity, it is helpful
  to have k be a TyVarTv, in parallel with other dependent variables.

* Duplicate skolemisation is expected.  When generalising in Step 3,
  we may find that one of the variables we want to quantify has
  already been skolemised.  For example, suppose we have already
  generalise S. When we come to T we'll find that kk1 (now the same as
  kk3) has already been skolemised.

  That's fine -- but it means that
    a) when collecting quantification candidates, in
       candidateQTyVarsOfKind, we must collect skolems
    b) quantifyTyVars should be a no-op on such a skolem
-}

--------------
tcExtendKindEnvWithTyCons :: [TcTyCon] -> TcM a -> TcM a
tcExtendKindEnvWithTyCons :: [TyCon] -> TcM a -> TcM a
tcExtendKindEnvWithTyCons tcs :: [TyCon]
tcs
  = [(Name, TcTyThing)] -> TcM a -> TcM a
forall r. [(Name, TcTyThing)] -> TcM r -> TcM r
tcExtendKindEnvList [ (TyCon -> Name
tyConName TyCon
tc, TyCon -> TcTyThing
ATcTyCon TyCon
tc) | TyCon
tc <- [TyCon]
tcs ]

--------------
mkPromotionErrorEnv :: [LTyClDecl GhcRn] -> TcTypeEnv
-- Maps each tycon/datacon to a suitable promotion error
--    tc :-> APromotionErr TyConPE
--    dc :-> APromotionErr RecDataConPE
--    See Note [Recursion and promoting data constructors]

mkPromotionErrorEnv :: [LTyClDecl GhcRn] -> NameEnv TcTyThing
mkPromotionErrorEnv decls :: [LTyClDecl GhcRn]
decls
  = (LTyClDecl GhcRn -> NameEnv TcTyThing -> NameEnv TcTyThing)
-> NameEnv TcTyThing -> [LTyClDecl GhcRn] -> NameEnv TcTyThing
forall (t :: * -> *) a b.
Foldable t =>
(a -> b -> b) -> b -> t a -> b
foldr (NameEnv TcTyThing -> NameEnv TcTyThing -> NameEnv TcTyThing
forall a. NameEnv a -> NameEnv a -> NameEnv a
plusNameEnv (NameEnv TcTyThing -> NameEnv TcTyThing -> NameEnv TcTyThing)
-> (LTyClDecl GhcRn -> NameEnv TcTyThing)
-> LTyClDecl GhcRn
-> NameEnv TcTyThing
-> NameEnv TcTyThing
forall b c a. (b -> c) -> (a -> b) -> a -> c
. TyClDecl GhcRn -> NameEnv TcTyThing
mk_prom_err_env (TyClDecl GhcRn -> NameEnv TcTyThing)
-> (LTyClDecl GhcRn -> TyClDecl GhcRn)
-> LTyClDecl GhcRn
-> NameEnv TcTyThing
forall b c a. (b -> c) -> (a -> b) -> a -> c
. LTyClDecl GhcRn -> TyClDecl GhcRn
forall a. HasSrcSpan a => a -> SrcSpanLess a
unLoc)
          NameEnv TcTyThing
forall a. NameEnv a
emptyNameEnv [LTyClDecl GhcRn]
decls

mk_prom_err_env :: TyClDecl GhcRn -> TcTypeEnv
mk_prom_err_env :: TyClDecl GhcRn -> NameEnv TcTyThing
mk_prom_err_env (ClassDecl { tcdLName :: forall pass. TyClDecl pass -> Located (IdP pass)
tcdLName = L _ nm :: IdP GhcRn
nm, tcdATs :: forall pass. TyClDecl pass -> [LFamilyDecl pass]
tcdATs = [LFamilyDecl GhcRn]
ats })
  = Name -> TcTyThing -> NameEnv TcTyThing
forall a. Name -> a -> NameEnv a
unitNameEnv Name
IdP GhcRn
nm (PromotionErr -> TcTyThing
APromotionErr PromotionErr
ClassPE)
    NameEnv TcTyThing -> NameEnv TcTyThing -> NameEnv TcTyThing
forall a. NameEnv a -> NameEnv a -> NameEnv a
`plusNameEnv`
    [(Name, TcTyThing)] -> NameEnv TcTyThing
forall a. [(Name, a)] -> NameEnv a
mkNameEnv [ (Name
SrcSpanLess (Located Name)
name, PromotionErr -> TcTyThing
APromotionErr PromotionErr
TyConPE)
              | (LFamilyDecl GhcRn -> Located (SrcSpanLess (LFamilyDecl GhcRn))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L _ (FamilyDecl { fdLName = (dL->L _ name) })) <- [LFamilyDecl GhcRn]
ats ]

mk_prom_err_env (DataDecl { tcdLName :: forall pass. TyClDecl pass -> Located (IdP pass)
tcdLName = (GenLocated SrcSpan (IdP GhcRn)
-> Located (SrcSpanLess (Located Name))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L _ name :: SrcSpanLess (Located Name)
name)
                          , tcdDataDefn :: forall pass. TyClDecl pass -> HsDataDefn pass
tcdDataDefn = HsDataDefn { dd_cons :: forall pass. HsDataDefn pass -> [LConDecl pass]
dd_cons = [LConDecl GhcRn]
cons } })
  = Name -> TcTyThing -> NameEnv TcTyThing
forall a. Name -> a -> NameEnv a
unitNameEnv Name
SrcSpanLess (Located Name)
name (PromotionErr -> TcTyThing
APromotionErr PromotionErr
TyConPE)
    NameEnv TcTyThing -> NameEnv TcTyThing -> NameEnv TcTyThing
forall a. NameEnv a -> NameEnv a -> NameEnv a
`plusNameEnv`
    [(Name, TcTyThing)] -> NameEnv TcTyThing
forall a. [(Name, a)] -> NameEnv a
mkNameEnv [ (Name
SrcSpanLess (Located Name)
con, PromotionErr -> TcTyThing
APromotionErr PromotionErr
RecDataConPE)
              | (LConDecl GhcRn -> Located (SrcSpanLess (LConDecl GhcRn))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L _ con' :: SrcSpanLess (LConDecl GhcRn)
con') <- [LConDecl GhcRn]
cons
              , (Located Name -> Located (SrcSpanLess (Located Name))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L _ con :: SrcSpanLess (Located Name)
con)  <- ConDecl GhcRn -> [GenLocated SrcSpan (IdP GhcRn)]
forall pass. ConDecl pass -> [Located (IdP pass)]
getConNames SrcSpanLess (LConDecl GhcRn)
ConDecl GhcRn
con' ]

mk_prom_err_env decl :: TyClDecl GhcRn
decl
  = Name -> TcTyThing -> NameEnv TcTyThing
forall a. Name -> a -> NameEnv a
unitNameEnv (TyClDecl GhcRn -> IdP GhcRn
forall pass. TyClDecl pass -> IdP pass
tcdName TyClDecl GhcRn
decl) (PromotionErr -> TcTyThing
APromotionErr PromotionErr
TyConPE)
    -- Works for family declarations too

--------------
getInitialKinds :: Bool -> [LTyClDecl GhcRn] -> TcM [TcTyCon]
-- Returns a TcTyCon for each TyCon bound by the decls,
-- each with its initial kind

getInitialKinds :: Bool -> [LTyClDecl GhcRn] -> TcM [TyCon]
getInitialKinds cusk :: Bool
cusk decls :: [LTyClDecl GhcRn]
decls
  = do { String -> SDoc -> TcRn ()
traceTc "getInitialKinds {" SDoc
empty
       ; [TyCon]
tcs <- (LTyClDecl GhcRn -> TcM [TyCon])
-> [LTyClDecl GhcRn] -> TcM [TyCon]
forall (m :: * -> *) a b. Monad m => (a -> m [b]) -> [a] -> m [b]
concatMapM ((SrcSpanLess (LTyClDecl GhcRn) -> TcM [TyCon])
-> LTyClDecl GhcRn -> TcM [TyCon]
forall a b. HasSrcSpan a => (SrcSpanLess a -> TcM b) -> a -> TcM b
addLocM (Bool -> TyClDecl GhcRn -> TcM [TyCon]
getInitialKind Bool
cusk)) [LTyClDecl GhcRn]
decls
       ; String -> SDoc -> TcRn ()
traceTc "getInitialKinds done }" SDoc
empty
       ; [TyCon] -> TcM [TyCon]
forall (m :: * -> *) a. Monad m => a -> m a
return [TyCon]
tcs }

getInitialKind :: Bool -> TyClDecl GhcRn -> TcM [TcTyCon]
-- Allocate a fresh kind variable for each TyCon and Class
-- For each tycon, return a TcTyCon with kind k
-- where k is the kind of tc, derived from the LHS
--         of the definition (and probably including
--         kind unification variables)
--      Example: data T a b = ...
--      return (T, kv1 -> kv2 -> kv3)
--
-- This pass deals with (ie incorporates into the kind it produces)
--   * The kind signatures on type-variable binders
--   * The result kinds signature on a TyClDecl
--
-- No family instances are passed to getInitialKinds

getInitialKind :: Bool -> TyClDecl GhcRn -> TcM [TyCon]
getInitialKind cusk :: Bool
cusk
    (ClassDecl { tcdLName :: forall pass. TyClDecl pass -> Located (IdP pass)
tcdLName = GenLocated SrcSpan (IdP GhcRn)
-> Located (SrcSpanLess (Located Name))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L _ name :: SrcSpanLess (Located Name)
name
               , tcdTyVars :: forall pass. TyClDecl pass -> LHsQTyVars pass
tcdTyVars = LHsQTyVars GhcRn
ktvs
               , tcdATs :: forall pass. TyClDecl pass -> [LFamilyDecl pass]
tcdATs = [LFamilyDecl GhcRn]
ats })
  = do { TyCon
tycon <- Name
-> TyConFlavour
-> Bool
-> LHsQTyVars GhcRn
-> TcM Kind
-> IOEnv (Env TcGblEnv TcLclEnv) TyCon
kcLHsQTyVars Name
SrcSpanLess (Located Name)
name TyConFlavour
ClassFlavour Bool
cusk LHsQTyVars GhcRn
ktvs (TcM Kind -> IOEnv (Env TcGblEnv TcLclEnv) TyCon)
-> TcM Kind -> IOEnv (Env TcGblEnv TcLclEnv) TyCon
forall a b. (a -> b) -> a -> b
$
                  Kind -> TcM Kind
forall (m :: * -> *) a. Monad m => a -> m a
return Kind
constraintKind
       ; let parent_tv_prs :: [(Name, TyVar)]
parent_tv_prs = TyCon -> [(Name, TyVar)]
tcTyConScopedTyVars TyCon
tycon
            -- See Note [Don't process associated types in kcLHsQTyVars]
       ; [TyCon]
inner_tcs <- [(Name, TyVar)] -> TcM [TyCon] -> TcM [TyCon]
forall r. [(Name, TyVar)] -> TcM r -> TcM r
tcExtendNameTyVarEnv [(Name, TyVar)]
parent_tv_prs (TcM [TyCon] -> TcM [TyCon]) -> TcM [TyCon] -> TcM [TyCon]
forall a b. (a -> b) -> a -> b
$
                      Maybe TyCon -> [LFamilyDecl GhcRn] -> TcM [TyCon]
getFamDeclInitialKinds (TyCon -> Maybe TyCon
forall a. a -> Maybe a
Just TyCon
tycon) [LFamilyDecl GhcRn]
ats
       ; [TyCon] -> TcM [TyCon]
forall (m :: * -> *) a. Monad m => a -> m a
return (TyCon
tycon TyCon -> [TyCon] -> [TyCon]
forall a. a -> [a] -> [a]
: [TyCon]
inner_tcs) }

getInitialKind cusk :: Bool
cusk
    (DataDecl { tcdLName :: forall pass. TyClDecl pass -> Located (IdP pass)
tcdLName = GenLocated SrcSpan (IdP GhcRn)
-> Located (SrcSpanLess (Located Name))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L _ name :: SrcSpanLess (Located Name)
name
              , tcdTyVars :: forall pass. TyClDecl pass -> LHsQTyVars pass
tcdTyVars = LHsQTyVars GhcRn
ktvs
              , tcdDataDefn :: forall pass. TyClDecl pass -> HsDataDefn pass
tcdDataDefn = HsDataDefn { dd_kindSig :: forall pass. HsDataDefn pass -> Maybe (LHsKind pass)
dd_kindSig = Maybe (LHsKind GhcRn)
m_sig
                                         , dd_ND :: forall pass. HsDataDefn pass -> NewOrData
dd_ND = NewOrData
new_or_data } })
  = do  { let flav :: TyConFlavour
flav = NewOrData -> TyConFlavour
newOrDataToFlavour NewOrData
new_or_data
        ; TyCon
tc <- Name
-> TyConFlavour
-> Bool
-> LHsQTyVars GhcRn
-> TcM Kind
-> IOEnv (Env TcGblEnv TcLclEnv) TyCon
kcLHsQTyVars Name
SrcSpanLess (Located Name)
name TyConFlavour
flav Bool
cusk LHsQTyVars GhcRn
ktvs (TcM Kind -> IOEnv (Env TcGblEnv TcLclEnv) TyCon)
-> TcM Kind -> IOEnv (Env TcGblEnv TcLclEnv) TyCon
forall a b. (a -> b) -> a -> b
$
                case Maybe (LHsKind GhcRn)
m_sig of
                   Just ksig :: LHsKind GhcRn
ksig -> UserTypeCtxt -> LHsKind GhcRn -> TcM Kind
tcLHsKindSig (Name -> UserTypeCtxt
DataKindCtxt Name
SrcSpanLess (Located Name)
name) LHsKind GhcRn
ksig
                   Nothing   -> Kind -> TcM Kind
forall (m :: * -> *) a. Monad m => a -> m a
return Kind
liftedTypeKind
        ; [TyCon] -> TcM [TyCon]
forall (m :: * -> *) a. Monad m => a -> m a
return [TyCon
tc] }

getInitialKind _ (FamDecl { tcdFam :: forall pass. TyClDecl pass -> FamilyDecl pass
tcdFam = FamilyDecl GhcRn
decl })
  = do { TyCon
tc <- Maybe TyCon
-> FamilyDecl GhcRn -> IOEnv (Env TcGblEnv TcLclEnv) TyCon
getFamDeclInitialKind Maybe TyCon
forall a. Maybe a
Nothing FamilyDecl GhcRn
decl
       ; [TyCon] -> TcM [TyCon]
forall (m :: * -> *) a. Monad m => a -> m a
return [TyCon
tc] }

getInitialKind cusk :: Bool
cusk (SynDecl { tcdLName :: forall pass. TyClDecl pass -> Located (IdP pass)
tcdLName = GenLocated SrcSpan (IdP GhcRn)
-> Located (SrcSpanLess (Located Name))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L _ name :: SrcSpanLess (Located Name)
name
                             , tcdTyVars :: forall pass. TyClDecl pass -> LHsQTyVars pass
tcdTyVars = LHsQTyVars GhcRn
ktvs
                             , tcdRhs :: forall pass. TyClDecl pass -> LHsType pass
tcdRhs = LHsKind GhcRn
rhs })
  = do  { TyCon
tycon <- Name
-> TyConFlavour
-> Bool
-> LHsQTyVars GhcRn
-> TcM Kind
-> IOEnv (Env TcGblEnv TcLclEnv) TyCon
kcLHsQTyVars Name
SrcSpanLess (Located Name)
name TyConFlavour
TypeSynonymFlavour Bool
cusk LHsQTyVars GhcRn
ktvs (TcM Kind -> IOEnv (Env TcGblEnv TcLclEnv) TyCon)
-> TcM Kind -> IOEnv (Env TcGblEnv TcLclEnv) TyCon
forall a b. (a -> b) -> a -> b
$
                   case LHsKind GhcRn -> Maybe (LHsKind GhcRn)
forall pass. LHsType pass -> Maybe (LHsType pass)
kind_annotation LHsKind GhcRn
rhs of
                     Just ksig :: LHsKind GhcRn
ksig -> UserTypeCtxt -> LHsKind GhcRn -> TcM Kind
tcLHsKindSig (Name -> UserTypeCtxt
TySynKindCtxt Name
SrcSpanLess (Located Name)
name) LHsKind GhcRn
ksig
                     Nothing   -> TcM Kind
newMetaKindVar
        ; [TyCon] -> TcM [TyCon]
forall (m :: * -> *) a. Monad m => a -> m a
return [TyCon
tycon] }
  where
    -- Keep this synchronized with 'hsDeclHasCusk'.
    kind_annotation :: LHsType pass -> Maybe (LHsType pass)
kind_annotation (LHsType pass -> Located (SrcSpanLess (LHsType pass))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L _ ty :: SrcSpanLess (LHsType pass)
ty) = case SrcSpanLess (LHsType pass)
ty of
        HsParTy _ lty     -> LHsType pass -> Maybe (LHsType pass)
kind_annotation LHsType pass
lty
        HsKindSig _ _ k   -> LHsType pass -> Maybe (LHsType pass)
forall a. a -> Maybe a
Just LHsType pass
k
        _                 -> Maybe (LHsType pass)
forall a. Maybe a
Nothing

getInitialKind _ (DataDecl _ _ _ _ (XHsDataDefn _)) = String -> TcM [TyCon]
forall a. String -> a
panic "getInitialKind"
getInitialKind _ (XTyClDecl _) = String -> TcM [TyCon]
forall a. String -> a
panic "getInitialKind"

---------------------------------
getFamDeclInitialKinds
  :: Maybe TcTyCon -- ^ Enclosing class TcTyCon, if any
  -> [LFamilyDecl GhcRn]
  -> TcM [TcTyCon]
getFamDeclInitialKinds :: Maybe TyCon -> [LFamilyDecl GhcRn] -> TcM [TyCon]
getFamDeclInitialKinds mb_parent_tycon :: Maybe TyCon
mb_parent_tycon decls :: [LFamilyDecl GhcRn]
decls
  = (LFamilyDecl GhcRn -> IOEnv (Env TcGblEnv TcLclEnv) TyCon)
-> [LFamilyDecl GhcRn] -> TcM [TyCon]
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
mapM ((SrcSpanLess (LFamilyDecl GhcRn)
 -> IOEnv (Env TcGblEnv TcLclEnv) TyCon)
-> LFamilyDecl GhcRn -> IOEnv (Env TcGblEnv TcLclEnv) TyCon
forall a b. HasSrcSpan a => (SrcSpanLess a -> TcM b) -> a -> TcM b
addLocM (Maybe TyCon
-> FamilyDecl GhcRn -> IOEnv (Env TcGblEnv TcLclEnv) TyCon
getFamDeclInitialKind Maybe TyCon
mb_parent_tycon)) [LFamilyDecl GhcRn]
decls

getFamDeclInitialKind
  :: Maybe TcTyCon -- ^ Enclosing class TcTyCon, if any
  -> FamilyDecl GhcRn
  -> TcM TcTyCon
getFamDeclInitialKind :: Maybe TyCon
-> FamilyDecl GhcRn -> IOEnv (Env TcGblEnv TcLclEnv) TyCon
getFamDeclInitialKind mb_parent_tycon :: Maybe TyCon
mb_parent_tycon
    decl :: FamilyDecl GhcRn
decl@(FamilyDecl { fdLName :: forall pass. FamilyDecl pass -> Located (IdP pass)
fdLName     = (GenLocated SrcSpan (IdP GhcRn)
-> Located (SrcSpanLess (Located Name))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L _ name :: SrcSpanLess (Located Name)
name)
                     , fdTyVars :: forall pass. FamilyDecl pass -> LHsQTyVars pass
fdTyVars    = LHsQTyVars GhcRn
ktvs
                     , fdResultSig :: forall pass. FamilyDecl pass -> LFamilyResultSig pass
fdResultSig = (LFamilyResultSig GhcRn
-> Located (SrcSpanLess (LFamilyResultSig GhcRn))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L _ resultSig :: SrcSpanLess (LFamilyResultSig GhcRn)
resultSig)
                     , fdInfo :: forall pass. FamilyDecl pass -> FamilyInfo pass
fdInfo      = FamilyInfo GhcRn
info })
  = Name
-> TyConFlavour
-> Bool
-> LHsQTyVars GhcRn
-> TcM Kind
-> IOEnv (Env TcGblEnv TcLclEnv) TyCon
kcLHsQTyVars Name
SrcSpanLess (Located Name)
name TyConFlavour
flav Bool
cusk LHsQTyVars GhcRn
ktvs (TcM Kind -> IOEnv (Env TcGblEnv TcLclEnv) TyCon)
-> TcM Kind -> IOEnv (Env TcGblEnv TcLclEnv) TyCon
forall a b. (a -> b) -> a -> b
$
    case SrcSpanLess (LFamilyResultSig GhcRn)
resultSig of
      KindSig _ ki                              -> UserTypeCtxt -> LHsKind GhcRn -> TcM Kind
tcLHsKindSig UserTypeCtxt
ctxt LHsKind GhcRn
ki
      TyVarSig _ (dL->L _ (KindedTyVar _ _ ki)) -> UserTypeCtxt -> LHsKind GhcRn -> TcM Kind
tcLHsKindSig UserTypeCtxt
ctxt LHsKind GhcRn
ki
      _ -- open type families have * return kind by default
        | TyConFlavour -> Bool
tcFlavourIsOpen TyConFlavour
flav              -> Kind -> TcM Kind
forall (m :: * -> *) a. Monad m => a -> m a
return Kind
liftedTypeKind
               -- closed type families have their return kind inferred
               -- by default
        | Bool
otherwise                         -> TcM Kind
newMetaKindVar
  where
    mb_cusk :: Maybe Bool
mb_cusk = TyCon -> Bool
tcTyConIsPoly (TyCon -> Bool) -> Maybe TyCon -> Maybe Bool
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> Maybe TyCon
mb_parent_tycon
    cusk :: Bool
cusk    = Maybe Bool -> FamilyDecl GhcRn -> Bool
forall pass. Maybe Bool -> FamilyDecl pass -> Bool
famDeclHasCusk Maybe Bool
mb_cusk FamilyDecl GhcRn
decl
    flav :: TyConFlavour
flav  = case FamilyInfo GhcRn
info of
      DataFamily         -> Maybe TyCon -> TyConFlavour
DataFamilyFlavour Maybe TyCon
mb_parent_tycon
      OpenTypeFamily     -> Maybe TyCon -> TyConFlavour
OpenTypeFamilyFlavour Maybe TyCon
mb_parent_tycon
      ClosedTypeFamily _ -> ASSERT( isNothing mb_parent_tycon )
                            TyConFlavour
ClosedTypeFamilyFlavour
    ctxt :: UserTypeCtxt
ctxt  = Name -> UserTypeCtxt
TyFamResKindCtxt Name
SrcSpanLess (Located Name)
name
getFamDeclInitialKind _ (XFamilyDecl _) = String -> IOEnv (Env TcGblEnv TcLclEnv) TyCon
forall a. String -> a
panic "getFamDeclInitialKind"

------------------------------------------------------------------------
kcLTyClDecl :: LTyClDecl GhcRn -> TcM ()
  -- See Note [Kind checking for type and class decls]
kcLTyClDecl :: LTyClDecl GhcRn -> TcRn ()
kcLTyClDecl (LTyClDecl GhcRn -> Located (SrcSpanLess (LTyClDecl GhcRn))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L loc :: SrcSpan
loc decl :: SrcSpanLess (LTyClDecl GhcRn)
decl)
  = SrcSpan -> TcRn () -> TcRn ()
forall a. SrcSpan -> TcRn a -> TcRn a
setSrcSpan SrcSpan
loc (TcRn () -> TcRn ()) -> TcRn () -> TcRn ()
forall a b. (a -> b) -> a -> b
$
    TyClDecl GhcRn -> TcRn () -> TcRn ()
forall a. TyClDecl GhcRn -> TcM a -> TcM a
tcAddDeclCtxt SrcSpanLess (LTyClDecl GhcRn)
TyClDecl GhcRn
decl (TcRn () -> TcRn ()) -> TcRn () -> TcRn ()
forall a b. (a -> b) -> a -> b
$
    do { String -> SDoc -> TcRn ()
traceTc "kcTyClDecl {" (Located Name -> SDoc
forall a. Outputable a => a -> SDoc
ppr Located Name
GenLocated SrcSpan (IdP GhcRn)
tc_name)
       ; TyClDecl GhcRn -> TcRn ()
kcTyClDecl SrcSpanLess (LTyClDecl GhcRn)
TyClDecl GhcRn
decl
       ; String -> SDoc -> TcRn ()
traceTc "kcTyClDecl done }" (Located Name -> SDoc
forall a. Outputable a => a -> SDoc
ppr Located Name
GenLocated SrcSpan (IdP GhcRn)
tc_name) }
  where
    tc_name :: GenLocated SrcSpan (IdP GhcRn)
tc_name = TyClDecl GhcRn -> GenLocated SrcSpan (IdP GhcRn)
forall pass. TyClDecl pass -> Located (IdP pass)
tyClDeclLName SrcSpanLess (LTyClDecl GhcRn)
TyClDecl GhcRn
decl

kcTyClDecl :: TyClDecl GhcRn -> TcM ()
-- This function is used solely for its side effect on kind variables
-- NB kind signatures on the type variables and
--    result kind signature have already been dealt with
--    by getInitialKind, so we can ignore them here.

kcTyClDecl :: TyClDecl GhcRn -> TcRn ()
kcTyClDecl (DataDecl { tcdLName :: forall pass. TyClDecl pass -> Located (IdP pass)
tcdLName    = (GenLocated SrcSpan (IdP GhcRn)
-> Located (SrcSpanLess (Located Name))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L _ name :: SrcSpanLess (Located Name)
name)
                     , tcdDataDefn :: forall pass. TyClDecl pass -> HsDataDefn pass
tcdDataDefn = HsDataDefn GhcRn
defn })
  | HsDataDefn { dd_cons :: forall pass. HsDataDefn pass -> [LConDecl pass]
dd_cons = cons :: [LConDecl GhcRn]
cons@((LConDecl GhcRn -> Located (SrcSpanLess (LConDecl GhcRn))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L _ (ConDeclGADT {})) : _)
               , dd_ctxt :: forall pass. HsDataDefn pass -> LHsContext pass
dd_ctxt = (LHsContext GhcRn -> Located (SrcSpanLess (LHsContext GhcRn))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L _ []) } <- HsDataDefn GhcRn
defn
  = (LConDecl GhcRn -> TcRn ()) -> [LConDecl GhcRn] -> TcRn ()
forall (t :: * -> *) (m :: * -> *) a b.
(Foldable t, Monad m) =>
(a -> m b) -> t a -> m ()
mapM_ ((SrcSpanLess (LConDecl GhcRn) -> TcRn ())
-> LConDecl GhcRn -> TcRn ()
forall a.
HasSrcSpan a =>
(SrcSpanLess a -> TcRn ()) -> a -> TcRn ()
wrapLocM_ SrcSpanLess (LConDecl GhcRn) -> TcRn ()
ConDecl GhcRn -> TcRn ()
kcConDecl) [LConDecl GhcRn]
cons
    -- hs_tvs and dd_kindSig already dealt with in getInitialKind
    -- This must be a GADT-style decl,
    --        (see invariants of DataDefn declaration)
    -- so (a) we don't need to bring the hs_tvs into scope, because the
    --        ConDecls bind all their own variables
    --    (b) dd_ctxt is not allowed for GADT-style decls, so we can ignore it

  | HsDataDefn { dd_ctxt :: forall pass. HsDataDefn pass -> LHsContext pass
dd_ctxt = LHsContext GhcRn
ctxt, dd_cons :: forall pass. HsDataDefn pass -> [LConDecl pass]
dd_cons = [LConDecl GhcRn]
cons } <- HsDataDefn GhcRn
defn
  = Name -> ([TyConBinder] -> Kind -> TcRn ()) -> TcRn ()
forall a. Name -> ([TyConBinder] -> Kind -> TcM a) -> TcM a
bindTyClTyVars Name
SrcSpanLess (Located Name)
name (([TyConBinder] -> Kind -> TcRn ()) -> TcRn ())
-> ([TyConBinder] -> Kind -> TcRn ()) -> TcRn ()
forall a b. (a -> b) -> a -> b
$ \ _ _ ->
    do  { [Kind]
_ <- LHsContext GhcRn -> TcM [Kind]
tcHsContext LHsContext GhcRn
ctxt
        ; (LConDecl GhcRn -> TcRn ()) -> [LConDecl GhcRn] -> TcRn ()
forall (t :: * -> *) (m :: * -> *) a b.
(Foldable t, Monad m) =>
(a -> m b) -> t a -> m ()
mapM_ ((SrcSpanLess (LConDecl GhcRn) -> TcRn ())
-> LConDecl GhcRn -> TcRn ()
forall a.
HasSrcSpan a =>
(SrcSpanLess a -> TcRn ()) -> a -> TcRn ()
wrapLocM_ SrcSpanLess (LConDecl GhcRn) -> TcRn ()
ConDecl GhcRn -> TcRn ()
kcConDecl) [LConDecl GhcRn]
cons }

kcTyClDecl (SynDecl { tcdLName :: forall pass. TyClDecl pass -> Located (IdP pass)
tcdLName = GenLocated SrcSpan (IdP GhcRn)
-> Located (SrcSpanLess (Located Name))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L _ name :: SrcSpanLess (Located Name)
name, tcdRhs :: forall pass. TyClDecl pass -> LHsType pass
tcdRhs = LHsKind GhcRn
rhs })
  = Name -> ([TyConBinder] -> Kind -> TcRn ()) -> TcRn ()
forall a. Name -> ([TyConBinder] -> Kind -> TcM a) -> TcM a
bindTyClTyVars Name
SrcSpanLess (Located Name)
name (([TyConBinder] -> Kind -> TcRn ()) -> TcRn ())
-> ([TyConBinder] -> Kind -> TcRn ()) -> TcRn ()
forall a b. (a -> b) -> a -> b
$ \ _ res_kind :: Kind
res_kind ->
    TcM Kind -> TcRn ()
forall a. TcM a -> TcRn ()
discardResult (TcM Kind -> TcRn ()) -> TcM Kind -> TcRn ()
forall a b. (a -> b) -> a -> b
$ LHsKind GhcRn -> Kind -> TcM Kind
tcCheckLHsType LHsKind GhcRn
rhs Kind
res_kind
        -- NB: check against the result kind that we allocated
        -- in getInitialKinds.

kcTyClDecl (ClassDecl { tcdLName :: forall pass. TyClDecl pass -> Located (IdP pass)
tcdLName = (GenLocated SrcSpan (IdP GhcRn)
-> Located (SrcSpanLess (Located Name))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L _ name :: SrcSpanLess (Located Name)
name)
                      , tcdCtxt :: forall pass. TyClDecl pass -> LHsContext pass
tcdCtxt = LHsContext GhcRn
ctxt, tcdSigs :: forall pass. TyClDecl pass -> [LSig pass]
tcdSigs = [LSig GhcRn]
sigs })
  = Name -> ([TyConBinder] -> Kind -> TcRn ()) -> TcRn ()
forall a. Name -> ([TyConBinder] -> Kind -> TcM a) -> TcM a
bindTyClTyVars Name
SrcSpanLess (Located Name)
name (([TyConBinder] -> Kind -> TcRn ()) -> TcRn ())
-> ([TyConBinder] -> Kind -> TcRn ()) -> TcRn ()
forall a b. (a -> b) -> a -> b
$ \ _ _ ->
    do  { [Kind]
_ <- LHsContext GhcRn -> TcM [Kind]
tcHsContext LHsContext GhcRn
ctxt
        ; (LSig GhcRn -> TcRn ()) -> [LSig GhcRn] -> TcRn ()
forall (t :: * -> *) (m :: * -> *) a b.
(Foldable t, Monad m) =>
(a -> m b) -> t a -> m ()
mapM_ ((SrcSpanLess (LSig GhcRn) -> TcRn ()) -> LSig GhcRn -> TcRn ()
forall a.
HasSrcSpan a =>
(SrcSpanLess a -> TcRn ()) -> a -> TcRn ()
wrapLocM_ SrcSpanLess (LSig GhcRn) -> TcRn ()
Sig GhcRn -> TcRn ()
kc_sig) [LSig GhcRn]
sigs }
  where
    kc_sig :: Sig GhcRn -> TcRn ()
kc_sig (ClassOpSig _ _ nms :: [GenLocated SrcSpan (IdP GhcRn)]
nms op_ty :: LHsSigType GhcRn
op_ty) = SkolemInfo -> [Located Name] -> LHsSigType GhcRn -> TcRn ()
kcClassSigType SkolemInfo
skol_info [Located Name]
[GenLocated SrcSpan (IdP GhcRn)]
nms LHsSigType GhcRn
op_ty
    kc_sig _                          = () -> TcRn ()
forall (m :: * -> *) a. Monad m => a -> m a
return ()

    skol_info :: SkolemInfo
skol_info = TyConFlavour -> Name -> SkolemInfo
TyConSkol TyConFlavour
ClassFlavour Name
SrcSpanLess (Located Name)
name

kcTyClDecl (FamDecl _ (FamilyDecl { fdLName :: forall pass. FamilyDecl pass -> Located (IdP pass)
fdLName  = (GenLocated SrcSpan (IdP GhcRn)
-> Located (SrcSpanLess (Located Name))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L _ fam_tc_name :: SrcSpanLess (Located Name)
fam_tc_name)
                                  , fdInfo :: forall pass. FamilyDecl pass -> FamilyInfo pass
fdInfo   = FamilyInfo GhcRn
fd_info }))
-- closed type families look at their equations, but other families don't
-- do anything here
  = case FamilyInfo GhcRn
fd_info of
      ClosedTypeFamily (Just eqns :: [LTyFamInstEqn GhcRn]
eqns) ->
        do { TyCon
fam_tc <- Name -> IOEnv (Env TcGblEnv TcLclEnv) TyCon
kcLookupTcTyCon Name
SrcSpanLess (Located Name)
fam_tc_name
           ; (LTyFamInstEqn GhcRn -> TcRn ())
-> [LTyFamInstEqn GhcRn] -> TcRn ()
forall (t :: * -> *) (m :: * -> *) a b.
(Foldable t, Monad m) =>
(a -> m b) -> t a -> m ()
mapM_ (TyCon -> LTyFamInstEqn GhcRn -> TcRn ()
kcTyFamInstEqn TyCon
fam_tc) [LTyFamInstEqn GhcRn]
eqns }
      _ -> () -> TcRn ()
forall (m :: * -> *) a. Monad m => a -> m a
return ()
kcTyClDecl (FamDecl _ (XFamilyDecl _))              = String -> TcRn ()
forall a. String -> a
panic "kcTyClDecl"
kcTyClDecl (DataDecl _ _ _ _ (XHsDataDefn _)) = String -> TcRn ()
forall a. String -> a
panic "kcTyClDecl"
kcTyClDecl (XTyClDecl _)                            = String -> TcRn ()
forall a. String -> a
panic "kcTyClDecl"

-------------------
kcConDecl :: ConDecl GhcRn -> TcM ()
kcConDecl :: ConDecl GhcRn -> TcRn ()
kcConDecl (ConDeclH98 { con_name :: forall pass. ConDecl pass -> Located (IdP pass)
con_name = GenLocated SrcSpan (IdP GhcRn)
name, con_ex_tvs :: forall pass. ConDecl pass -> [LHsTyVarBndr pass]
con_ex_tvs = [LHsTyVarBndr GhcRn]
ex_tvs
                      , con_mb_cxt :: forall pass. ConDecl pass -> Maybe (LHsContext pass)
con_mb_cxt = Maybe (LHsContext GhcRn)
ex_ctxt, con_args :: forall pass. ConDecl pass -> HsConDeclDetails pass
con_args = HsConDeclDetails GhcRn
args })
  = SDoc -> TcRn () -> TcRn ()
forall a. SDoc -> TcM a -> TcM a
addErrCtxt ([Located Name] -> SDoc
dataConCtxtName [Located Name
GenLocated SrcSpan (IdP GhcRn)
name]) (TcRn () -> TcRn ()) -> TcRn () -> TcRn ()
forall a b. (a -> b) -> a -> b
$
    TcM ([TyVar], ()) -> TcRn ()
forall a. TcM a -> TcRn ()
discardResult                   (TcM ([TyVar], ()) -> TcRn ()) -> TcM ([TyVar], ()) -> TcRn ()
forall a b. (a -> b) -> a -> b
$
    [LHsTyVarBndr GhcRn] -> TcRn () -> TcM ([TyVar], ())
forall a. [LHsTyVarBndr GhcRn] -> TcM a -> TcM ([TyVar], a)
bindExplicitTKBndrs_Skol [LHsTyVarBndr GhcRn]
ex_tvs (TcRn () -> TcM ([TyVar], ())) -> TcRn () -> TcM ([TyVar], ())
forall a b. (a -> b) -> a -> b
$
    do { [Kind]
_ <- Maybe (LHsContext GhcRn) -> TcM [Kind]
tcHsMbContext Maybe (LHsContext GhcRn)
ex_ctxt
       ; String -> SDoc -> TcRn ()
traceTc "kcConDecl {" (Located Name -> SDoc
forall a. Outputable a => a -> SDoc
ppr Located Name
GenLocated SrcSpan (IdP GhcRn)
name SDoc -> SDoc -> SDoc
$$ HsConDeclDetails GhcRn -> SDoc
forall a. Outputable a => a -> SDoc
ppr HsConDeclDetails GhcRn
args)
       ; (LHsKind GhcRn -> TcM Kind) -> [LHsKind GhcRn] -> TcRn ()
forall (t :: * -> *) (m :: * -> *) a b.
(Foldable t, Monad m) =>
(a -> m b) -> t a -> m ()
mapM_ (LHsKind GhcRn -> TcM Kind
tcHsOpenType (LHsKind GhcRn -> TcM Kind)
-> (LHsKind GhcRn -> LHsKind GhcRn) -> LHsKind GhcRn -> TcM Kind
forall b c a. (b -> c) -> (a -> b) -> a -> c
. LHsKind GhcRn -> LHsKind GhcRn
forall a. LHsType a -> LHsType a
getBangType) (HsConDeclDetails GhcRn -> [LHsKind GhcRn]
forall pass. HsConDeclDetails pass -> [LBangType pass]
hsConDeclArgTys HsConDeclDetails GhcRn
args)
       ; String -> SDoc -> TcRn ()
traceTc "kcConDecl }" (Located Name -> SDoc
forall a. Outputable a => a -> SDoc
ppr Located Name
GenLocated SrcSpan (IdP GhcRn)
name)
       }
              -- We don't need to check the telescope here, because that's
              -- done in tcConDecl

kcConDecl (ConDeclGADT { con_names :: forall pass. ConDecl pass -> [Located (IdP pass)]
con_names = [GenLocated SrcSpan (IdP GhcRn)]
names
                       , con_qvars :: forall pass. ConDecl pass -> LHsQTyVars pass
con_qvars = LHsQTyVars GhcRn
qtvs, con_mb_cxt :: forall pass. ConDecl pass -> Maybe (LHsContext pass)
con_mb_cxt = Maybe (LHsContext GhcRn)
cxt
                       , con_args :: forall pass. ConDecl pass -> HsConDeclDetails pass
con_args = HsConDeclDetails GhcRn
args, con_res_ty :: forall pass. ConDecl pass -> LHsType pass
con_res_ty = LHsKind GhcRn
res_ty })
  | HsQTvs { hsq_ext :: forall pass. LHsQTyVars pass -> XHsQTvs pass
hsq_ext = HsQTvsRn { hsq_implicit = implicit_tkv_nms }
           , hsq_explicit :: forall pass. LHsQTyVars pass -> [LHsTyVarBndr pass]
hsq_explicit = [LHsTyVarBndr GhcRn]
explicit_tkv_nms } <- LHsQTyVars GhcRn
qtvs
  = -- Even though the data constructor's type is closed, we
    -- must still kind-check the type, because that may influence
    -- the inferred kind of the /type/ constructor.  Example:
    --    data T f a where
    --      MkT :: f a -> T f a
    -- If we don't look at MkT we won't get the correct kind
    -- for the type constructor T
    SDoc -> TcRn () -> TcRn ()
forall a. SDoc -> TcM a -> TcM a
addErrCtxt ([Located Name] -> SDoc
dataConCtxtName [Located Name]
[GenLocated SrcSpan (IdP GhcRn)]
names) (TcRn () -> TcRn ()) -> TcRn () -> TcRn ()
forall a b. (a -> b) -> a -> b
$
    TcM ([TyVar], ([TyVar], ())) -> TcRn ()
forall a. TcM a -> TcRn ()
discardResult (TcM ([TyVar], ([TyVar], ())) -> TcRn ())
-> TcM ([TyVar], ([TyVar], ())) -> TcRn ()
forall a b. (a -> b) -> a -> b
$
    [Name] -> TcM ([TyVar], ()) -> TcM ([TyVar], ([TyVar], ()))
forall a. [Name] -> TcM a -> TcM ([TyVar], a)
bindImplicitTKBndrs_Tv [Name]
implicit_tkv_nms (TcM ([TyVar], ()) -> TcM ([TyVar], ([TyVar], ())))
-> TcM ([TyVar], ()) -> TcM ([TyVar], ([TyVar], ()))
forall a b. (a -> b) -> a -> b
$
    [LHsTyVarBndr GhcRn] -> TcRn () -> TcM ([TyVar], ())
forall a. [LHsTyVarBndr GhcRn] -> TcM a -> TcM ([TyVar], a)
bindExplicitTKBndrs_Tv [LHsTyVarBndr GhcRn]
explicit_tkv_nms (TcRn () -> TcM ([TyVar], ())) -> TcRn () -> TcM ([TyVar], ())
forall a b. (a -> b) -> a -> b
$
        -- Why "_Tv"?  See Note [Kind-checking for GADTs]
    do { [Kind]
_ <- Maybe (LHsContext GhcRn) -> TcM [Kind]
tcHsMbContext Maybe (LHsContext GhcRn)
cxt
       ; (LHsKind GhcRn -> TcM Kind) -> [LHsKind GhcRn] -> TcRn ()
forall (t :: * -> *) (m :: * -> *) a b.
(Foldable t, Monad m) =>
(a -> m b) -> t a -> m ()
mapM_ (LHsKind GhcRn -> TcM Kind
tcHsOpenType (LHsKind GhcRn -> TcM Kind)
-> (LHsKind GhcRn -> LHsKind GhcRn) -> LHsKind GhcRn -> TcM Kind
forall b c a. (b -> c) -> (a -> b) -> a -> c
. LHsKind GhcRn -> LHsKind GhcRn
forall a. LHsType a -> LHsType a
getBangType) (HsConDeclDetails GhcRn -> [LHsKind GhcRn]
forall pass. HsConDeclDetails pass -> [LBangType pass]
hsConDeclArgTys HsConDeclDetails GhcRn
args)
       ; Kind
_ <- LHsKind GhcRn -> TcM Kind
tcHsOpenType LHsKind GhcRn
res_ty
       ; () -> TcRn ()
forall (m :: * -> *) a. Monad m => a -> m a
return () }
kcConDecl (XConDecl _) = String -> TcRn ()
forall a. String -> a
panic "kcConDecl"
kcConDecl (ConDeclGADT _ _ _ (XLHsQTyVars _) _ _ _ _) = String -> TcRn ()
forall a. String -> a
panic "kcConDecl"

{-
Note [Recursion and promoting data constructors]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
We don't want to allow promotion in a strongly connected component
when kind checking.

Consider:
  data T f = K (f (K Any))

When kind checking the `data T' declaration the local env contains the
mappings:
  T -> ATcTyCon <some initial kind>
  K -> APromotionErr

APromotionErr is only used for DataCons, and only used during type checking
in tcTyClGroup.

Note [Kind-checking for GADTs]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Consider

  data Proxy a where
    MkProxy1 :: forall k (b :: k). Proxy b
    MkProxy2 :: forall j (c :: j). Proxy c

It seems reasonable that this should be accepted. But something very strange
is going on here: when we're kind-checking this declaration, we need to unify
the kind of `a` with k and j -- even though k and j's scopes are local to the type of
MkProxy{1,2}. The best approach we've come up with is to use TyVarTvs during
the kind-checking pass. First off, note that it's OK if the kind-checking pass
is too permissive: we'll snag the problems in the type-checking pass later.
(This extra permissiveness might happen with something like

  data SameKind :: k -> k -> Type
  data Bad a where
    MkBad :: forall k1 k2 (a :: k1) (b :: k2). Bad (SameKind a b)

which would be accepted if k1 and k2 were TyVarTvs. This is correctly rejected
in the second pass, though. Test case: polykinds/TyVarTvKinds3)
Recall that the kind-checking pass exists solely to collect constraints
on the kinds and to power unification.

To achieve the use of TyVarTvs, we must be careful to use specialized functions
that produce TyVarTvs, not ordinary skolems. This is why we need
kcExplicitTKBndrs and kcImplicitTKBndrs in TcHsType, separate from their
tc... variants.

The drawback of this approach is sometimes it will accept a definition that
a (hypothetical) declarative specification would likely reject. As a general
rule, we don't want to allow polymorphic recursion without a CUSK. Indeed,
the whole point of CUSKs is to allow polymorphic recursion. Yet, the TyVarTvs
approach allows a limited form of polymorphic recursion *without* a CUSK.

To wit:
  data T a = forall k (b :: k). MkT (T b) Int
  (test case: dependent/should_compile/T14066a)

Note that this is polymorphically recursive, with the recursive occurrence
of T used at a kind other than a's kind. The approach outlined here accepts
this definition, because this kind is still a kind variable (and so the
TyVarTvs unify). Stepping back, I (Richard) have a hard time envisioning a
way to describe exactly what declarations will be accepted and which will
be rejected (without a CUSK). However, the accepted definitions are indeed
well-kinded and any rejected definitions would be accepted with a CUSK,
and so this wrinkle need not cause anyone to lose sleep.

************************************************************************
*                                                                      *
\subsection{Type checking}
*                                                                      *
************************************************************************

Note [Type checking recursive type and class declarations]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
At this point we have completed *kind-checking* of a mutually
recursive group of type/class decls (done in kcTyClGroup). However,
we discarded the kind-checked types (eg RHSs of data type decls);
note that kcTyClDecl returns ().  There are two reasons:

  * It's convenient, because we don't have to rebuild a
    kinded HsDecl (a fairly elaborate type)

  * It's necessary, because after kind-generalisation, the
    TyCons/Classes may now be kind-polymorphic, and hence need
    to be given kind arguments.

Example:
       data T f a = MkT (f a) (T f a)
During kind-checking, we give T the kind T :: k1 -> k2 -> *
and figure out constraints on k1, k2 etc. Then we generalise
to get   T :: forall k. (k->*) -> k -> *
So now the (T f a) in the RHS must be elaborated to (T k f a).

However, during tcTyClDecl of T (above) we will be in a recursive
"knot". So we aren't allowed to look at the TyCon T itself; we are only
allowed to put it (lazily) in the returned structures.  But when
kind-checking the RHS of T's decl, we *do* need to know T's kind (so
that we can correctly elaboarate (T k f a).  How can we get T's kind
without looking at T?  Delicate answer: during tcTyClDecl, we extend

  *Global* env with T -> ATyCon (the (not yet built) final TyCon for T)
  *Local*  env with T -> ATcTyCon (TcTyCon with the polymorphic kind of T)

Then:

  * During TcHsType.tcTyVar we look in the *local* env, to get the
    fully-known, not knot-tied TcTyCon for T.

  * Then, in TcHsSyn.zonkTcTypeToType (and zonkTcTyCon in particular)
    we look in the *global* env to get the TyCon.

This fancy footwork (with two bindings for T) is only necessary for the
TyCons or Classes of this recursive group.  Earlier, finished groups,
live in the global env only.

See also Note [Kind checking recursive type and class declarations]

Note [Kind checking recursive type and class declarations]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Before we can type-check the decls, we must kind check them. This
is done by establishing an "initial kind", which is a rather uninformed
guess at a tycon's kind (by counting arguments, mainly) and then
using this initial kind for recursive occurrences.

The initial kind is stored in exactly the same way during
kind-checking as it is during type-checking (Note [Type checking
recursive type and class declarations]): in the *local* environment,
with ATcTyCon. But we still must store *something* in the *global*
environment. Even though we discard the result of kind-checking, we
sometimes need to produce error messages. These error messages will
want to refer to the tycons being checked, except that they don't
exist yet, and it would be Terribly Annoying to get the error messages
to refer back to HsSyn. So we create a TcTyCon and put it in the
global env. This tycon can print out its name and knows its kind, but
any other action taken on it will panic. Note that TcTyCons are *not*
knot-tied, unlike the rather valid but knot-tied ones that occur
during type-checking.

Note [Declarations for wired-in things]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
For wired-in things we simply ignore the declaration
and take the wired-in information.  That avoids complications.
e.g. the need to make the data constructor worker name for
     a constraint tuple match the wired-in one
-}

tcTyClDecl :: RolesInfo -> LTyClDecl GhcRn -> TcM TyCon
tcTyClDecl :: (Name -> [Role])
-> LTyClDecl GhcRn -> IOEnv (Env TcGblEnv TcLclEnv) TyCon
tcTyClDecl roles_info :: Name -> [Role]
roles_info (LTyClDecl GhcRn -> Located (SrcSpanLess (LTyClDecl GhcRn))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L loc :: SrcSpan
loc decl :: SrcSpanLess (LTyClDecl GhcRn)
decl)
  | Just thing :: TyThing
thing <- Name -> Maybe TyThing
wiredInNameTyThing_maybe (TyClDecl GhcRn -> IdP GhcRn
forall pass. TyClDecl pass -> IdP pass
tcdName SrcSpanLess (LTyClDecl GhcRn)
TyClDecl GhcRn
decl)
  = case TyThing
thing of -- See Note [Declarations for wired-in things]
      ATyCon tc :: TyCon
tc -> TyCon -> IOEnv (Env TcGblEnv TcLclEnv) TyCon
forall (m :: * -> *) a. Monad m => a -> m a
return TyCon
tc
      _ -> String -> SDoc -> IOEnv (Env TcGblEnv TcLclEnv) TyCon
forall a. HasCallStack => String -> SDoc -> a
pprPanic "tcTyClDecl" (TyThing -> SDoc
forall a. Outputable a => a -> SDoc
ppr TyThing
thing)

  | Bool
otherwise
  = SrcSpan
-> IOEnv (Env TcGblEnv TcLclEnv) TyCon
-> IOEnv (Env TcGblEnv TcLclEnv) TyCon
forall a. SrcSpan -> TcRn a -> TcRn a
setSrcSpan SrcSpan
loc (IOEnv (Env TcGblEnv TcLclEnv) TyCon
 -> IOEnv (Env TcGblEnv TcLclEnv) TyCon)
-> IOEnv (Env TcGblEnv TcLclEnv) TyCon
-> IOEnv (Env TcGblEnv TcLclEnv) TyCon
forall a b. (a -> b) -> a -> b
$ TyClDecl GhcRn
-> IOEnv (Env TcGblEnv TcLclEnv) TyCon
-> IOEnv (Env TcGblEnv TcLclEnv) TyCon
forall a. TyClDecl GhcRn -> TcM a -> TcM a
tcAddDeclCtxt SrcSpanLess (LTyClDecl GhcRn)
TyClDecl GhcRn
decl (IOEnv (Env TcGblEnv TcLclEnv) TyCon
 -> IOEnv (Env TcGblEnv TcLclEnv) TyCon)
-> IOEnv (Env TcGblEnv TcLclEnv) TyCon
-> IOEnv (Env TcGblEnv TcLclEnv) TyCon
forall a b. (a -> b) -> a -> b
$
    do { String -> SDoc -> TcRn ()
traceTc "---- tcTyClDecl ---- {" (TyClDecl GhcRn -> SDoc
forall a. Outputable a => a -> SDoc
ppr SrcSpanLess (LTyClDecl GhcRn)
TyClDecl GhcRn
decl)
       ; TyCon
tc <- Maybe Class
-> (Name -> [Role])
-> TyClDecl GhcRn
-> IOEnv (Env TcGblEnv TcLclEnv) TyCon
tcTyClDecl1 Maybe Class
forall a. Maybe a
Nothing Name -> [Role]
roles_info SrcSpanLess (LTyClDecl GhcRn)
TyClDecl GhcRn
decl
       ; String -> SDoc -> TcRn ()
traceTc "---- tcTyClDecl end ---- }" (TyCon -> SDoc
forall a. Outputable a => a -> SDoc
ppr TyCon
tc)
       ; TyCon -> IOEnv (Env TcGblEnv TcLclEnv) TyCon
forall (m :: * -> *) a. Monad m => a -> m a
return TyCon
tc }

  -- "type family" declarations
tcTyClDecl1 :: Maybe Class -> RolesInfo -> TyClDecl GhcRn -> TcM TyCon
tcTyClDecl1 :: Maybe Class
-> (Name -> [Role])
-> TyClDecl GhcRn
-> IOEnv (Env TcGblEnv TcLclEnv) TyCon
tcTyClDecl1 parent :: Maybe Class
parent _roles_info :: Name -> [Role]
_roles_info (FamDecl { tcdFam :: forall pass. TyClDecl pass -> FamilyDecl pass
tcdFam = FamilyDecl GhcRn
fd })
  = Maybe Class
-> FamilyDecl GhcRn -> IOEnv (Env TcGblEnv TcLclEnv) TyCon
tcFamDecl1 Maybe Class
parent FamilyDecl GhcRn
fd

  -- "type" synonym declaration
tcTyClDecl1 _parent :: Maybe Class
_parent roles_info :: Name -> [Role]
roles_info
            (SynDecl { tcdLName :: forall pass. TyClDecl pass -> Located (IdP pass)
tcdLName = (GenLocated SrcSpan (IdP GhcRn)
-> Located (SrcSpanLess (Located Name))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L _ tc_name :: SrcSpanLess (Located Name)
tc_name)
                     , tcdRhs :: forall pass. TyClDecl pass -> LHsType pass
tcdRhs   = LHsKind GhcRn
rhs })
  = ASSERT( isNothing _parent )
    Name
-> ([TyConBinder] -> Kind -> IOEnv (Env TcGblEnv TcLclEnv) TyCon)
-> IOEnv (Env TcGblEnv TcLclEnv) TyCon
forall a. Name -> ([TyConBinder] -> Kind -> TcM a) -> TcM a
bindTyClTyVars Name
SrcSpanLess (Located Name)
tc_name (([TyConBinder] -> Kind -> IOEnv (Env TcGblEnv TcLclEnv) TyCon)
 -> IOEnv (Env TcGblEnv TcLclEnv) TyCon)
-> ([TyConBinder] -> Kind -> IOEnv (Env TcGblEnv TcLclEnv) TyCon)
-> IOEnv (Env TcGblEnv TcLclEnv) TyCon
forall a b. (a -> b) -> a -> b
$ \ binders :: [TyConBinder]
binders res_kind :: Kind
res_kind ->
    (Name -> [Role])
-> Name
-> [TyConBinder]
-> Kind
-> LHsKind GhcRn
-> IOEnv (Env TcGblEnv TcLclEnv) TyCon
tcTySynRhs Name -> [Role]
roles_info Name
SrcSpanLess (Located Name)
tc_name [TyConBinder]
binders Kind
res_kind LHsKind GhcRn
rhs

  -- "data/newtype" declaration
tcTyClDecl1 _parent :: Maybe Class
_parent roles_info :: Name -> [Role]
roles_info
            (DataDecl { tcdLName :: forall pass. TyClDecl pass -> Located (IdP pass)
tcdLName = (GenLocated SrcSpan (IdP GhcRn)
-> Located (SrcSpanLess (Located Name))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L _ tc_name :: SrcSpanLess (Located Name)
tc_name)
                      , tcdDataDefn :: forall pass. TyClDecl pass -> HsDataDefn pass
tcdDataDefn = HsDataDefn GhcRn
defn })
  = ASSERT( isNothing _parent )
    Name
-> ([TyConBinder] -> Kind -> IOEnv (Env TcGblEnv TcLclEnv) TyCon)
-> IOEnv (Env TcGblEnv TcLclEnv) TyCon
forall a. Name -> ([TyConBinder] -> Kind -> TcM a) -> TcM a
bindTyClTyVars Name
SrcSpanLess (Located Name)
tc_name (([TyConBinder] -> Kind -> IOEnv (Env TcGblEnv TcLclEnv) TyCon)
 -> IOEnv (Env TcGblEnv TcLclEnv) TyCon)
-> ([TyConBinder] -> Kind -> IOEnv (Env TcGblEnv TcLclEnv) TyCon)
-> IOEnv (Env TcGblEnv TcLclEnv) TyCon
forall a b. (a -> b) -> a -> b
$ \ tycon_binders :: [TyConBinder]
tycon_binders res_kind :: Kind
res_kind ->
    (Name -> [Role])
-> Name
-> [TyConBinder]
-> Kind
-> HsDataDefn GhcRn
-> IOEnv (Env TcGblEnv TcLclEnv) TyCon
tcDataDefn Name -> [Role]
roles_info Name
SrcSpanLess (Located Name)
tc_name [TyConBinder]
tycon_binders Kind
res_kind HsDataDefn GhcRn
defn

tcTyClDecl1 _parent :: Maybe Class
_parent roles_info :: Name -> [Role]
roles_info
            (ClassDecl { tcdLName :: forall pass. TyClDecl pass -> Located (IdP pass)
tcdLName = (GenLocated SrcSpan (IdP GhcRn)
-> Located (SrcSpanLess (Located Name))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L _ class_name :: SrcSpanLess (Located Name)
class_name)
                       , tcdCtxt :: forall pass. TyClDecl pass -> LHsContext pass
tcdCtxt = LHsContext GhcRn
hs_ctxt
                       , tcdMeths :: forall pass. TyClDecl pass -> LHsBinds pass
tcdMeths = LHsBinds GhcRn
meths
                       , tcdFDs :: forall pass. TyClDecl pass -> [LHsFunDep pass]
tcdFDs = [LHsFunDep GhcRn]
fundeps
                       , tcdSigs :: forall pass. TyClDecl pass -> [LSig pass]
tcdSigs = [LSig GhcRn]
sigs
                       , tcdATs :: forall pass. TyClDecl pass -> [LFamilyDecl pass]
tcdATs = [LFamilyDecl GhcRn]
ats
                       , tcdATDefs :: forall pass. TyClDecl pass -> [LTyFamDefltEqn pass]
tcdATDefs = [LTyFamDefltEqn GhcRn]
at_defs })
  = ASSERT( isNothing _parent )
    do { Class
clas <- (Name -> [Role])
-> Name
-> LHsContext GhcRn
-> LHsBinds GhcRn
-> [LHsFunDep GhcRn]
-> [LSig GhcRn]
-> [LFamilyDecl GhcRn]
-> [LTyFamDefltEqn GhcRn]
-> TcM Class
tcClassDecl1 Name -> [Role]
roles_info Name
SrcSpanLess (Located Name)
class_name LHsContext GhcRn
hs_ctxt
                              LHsBinds GhcRn
meths [LHsFunDep GhcRn]
fundeps [LSig GhcRn]
sigs [LFamilyDecl GhcRn]
ats [LTyFamDefltEqn GhcRn]
at_defs
       ; TyCon -> IOEnv (Env TcGblEnv TcLclEnv) TyCon
forall (m :: * -> *) a. Monad m => a -> m a
return (Class -> TyCon
classTyCon Class
clas) }

tcTyClDecl1 _ _ (XTyClDecl _) = String -> IOEnv (Env TcGblEnv TcLclEnv) TyCon
forall a. String -> a
panic "tcTyClDecl1"


{- *********************************************************************
*                                                                      *
          Class declarations
*                                                                      *
********************************************************************* -}

tcClassDecl1 :: RolesInfo -> Name -> LHsContext GhcRn
             -> LHsBinds GhcRn -> [LHsFunDep GhcRn] -> [LSig GhcRn]
             -> [LFamilyDecl GhcRn] -> [LTyFamDefltEqn GhcRn]
             -> TcM Class
tcClassDecl1 :: (Name -> [Role])
-> Name
-> LHsContext GhcRn
-> LHsBinds GhcRn
-> [LHsFunDep GhcRn]
-> [LSig GhcRn]
-> [LFamilyDecl GhcRn]
-> [LTyFamDefltEqn GhcRn]
-> TcM Class
tcClassDecl1 roles_info :: Name -> [Role]
roles_info class_name :: Name
class_name hs_ctxt :: LHsContext GhcRn
hs_ctxt meths :: LHsBinds GhcRn
meths fundeps :: [LHsFunDep GhcRn]
fundeps sigs :: [LSig GhcRn]
sigs ats :: [LFamilyDecl GhcRn]
ats at_defs :: [LTyFamDefltEqn GhcRn]
at_defs
  = (Class -> TcM Class) -> TcM Class
forall a env. (a -> IOEnv env a) -> IOEnv env a
fixM ((Class -> TcM Class) -> TcM Class)
-> (Class -> TcM Class) -> TcM Class
forall a b. (a -> b) -> a -> b
$ \ clas :: Class
clas ->
    -- We need the knot because 'clas' is passed into tcClassATs
    Name -> ([TyConBinder] -> Kind -> TcM Class) -> TcM Class
forall a. Name -> ([TyConBinder] -> Kind -> TcM a) -> TcM a
bindTyClTyVars Name
class_name (([TyConBinder] -> Kind -> TcM Class) -> TcM Class)
-> ([TyConBinder] -> Kind -> TcM Class) -> TcM Class
forall a b. (a -> b) -> a -> b
$ \ binders :: [TyConBinder]
binders res_kind :: Kind
res_kind ->
    do { MASSERT2( tcIsConstraintKind res_kind
                 , ppr class_name $$ ppr res_kind )
       ; String -> SDoc -> TcRn ()
traceTc "tcClassDecl 1" (Name -> SDoc
forall a. Outputable a => a -> SDoc
ppr Name
class_name SDoc -> SDoc -> SDoc
$$ [TyConBinder] -> SDoc
forall a. Outputable a => a -> SDoc
ppr [TyConBinder]
binders)
       ; let tycon_name :: Name
tycon_name = Name
class_name        -- We use the same name
             roles :: [Role]
roles = Name -> [Role]
roles_info Name
tycon_name  -- for TyCon and Class

       ; (ctxt :: [Kind]
ctxt, fds :: [([TyVar], [TyVar])]
fds, sig_stuff :: [TcMethInfo]
sig_stuff, at_stuff :: [ClassATItem]
at_stuff)
            <- TcM ([Kind], [([TyVar], [TyVar])], [TcMethInfo], [ClassATItem])
-> TcM ([Kind], [([TyVar], [TyVar])], [TcMethInfo], [ClassATItem])
forall r. TcM r -> TcM r
pushTcLevelM_   (TcM ([Kind], [([TyVar], [TyVar])], [TcMethInfo], [ClassATItem])
 -> TcM ([Kind], [([TyVar], [TyVar])], [TcMethInfo], [ClassATItem]))
-> TcM ([Kind], [([TyVar], [TyVar])], [TcMethInfo], [ClassATItem])
-> TcM ([Kind], [([TyVar], [TyVar])], [TcMethInfo], [ClassATItem])
forall a b. (a -> b) -> a -> b
$
               TcM ([Kind], [([TyVar], [TyVar])], [TcMethInfo], [ClassATItem])
-> TcM ([Kind], [([TyVar], [TyVar])], [TcMethInfo], [ClassATItem])
forall r. TcM r -> TcM r
solveEqualities (TcM ([Kind], [([TyVar], [TyVar])], [TcMethInfo], [ClassATItem])
 -> TcM ([Kind], [([TyVar], [TyVar])], [TcMethInfo], [ClassATItem]))
-> TcM ([Kind], [([TyVar], [TyVar])], [TcMethInfo], [ClassATItem])
-> TcM ([Kind], [([TyVar], [TyVar])], [TcMethInfo], [ClassATItem])
forall a b. (a -> b) -> a -> b
$
               do { [Kind]
ctxt <- LHsContext GhcRn -> TcM [Kind]
tcHsContext LHsContext GhcRn
hs_ctxt
                  ; [([TyVar], [TyVar])]
fds  <- (Located (FunDep (Located Name))
 -> IOEnv (Env TcGblEnv TcLclEnv) ([TyVar], [TyVar]))
-> [Located (FunDep (Located Name))]
-> IOEnv (Env TcGblEnv TcLclEnv) [([TyVar], [TyVar])]
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
mapM ((SrcSpanLess (Located (FunDep (Located Name)))
 -> IOEnv (Env TcGblEnv TcLclEnv) ([TyVar], [TyVar]))
-> Located (FunDep (Located Name))
-> IOEnv (Env TcGblEnv TcLclEnv) ([TyVar], [TyVar])
forall a b. HasSrcSpan a => (SrcSpanLess a -> TcM b) -> a -> TcM b
addLocM SrcSpanLess (Located (FunDep (Located Name)))
-> IOEnv (Env TcGblEnv TcLclEnv) ([TyVar], [TyVar])
forall (t :: * -> *) (t :: * -> *) a a.
(Traversable t, Traversable t, HasSrcSpan a, HasSrcSpan a,
 SrcSpanLess a ~ Name, SrcSpanLess a ~ Name) =>
(t a, t a) -> IOEnv (Env TcGblEnv TcLclEnv) (t TyVar, t TyVar)
tc_fundep) [Located (FunDep (Located Name))]
[LHsFunDep GhcRn]
fundeps
                  ; [TcMethInfo]
sig_stuff <- Name -> [LSig GhcRn] -> LHsBinds GhcRn -> TcM [TcMethInfo]
tcClassSigs Name
class_name [LSig GhcRn]
sigs LHsBinds GhcRn
meths
                  ; [ClassATItem]
at_stuff  <- Name
-> Class
-> [LFamilyDecl GhcRn]
-> [LTyFamDefltEqn GhcRn]
-> TcM [ClassATItem]
tcClassATs Name
class_name Class
clas [LFamilyDecl GhcRn]
ats [LTyFamDefltEqn GhcRn]
at_defs
                  ; ([Kind], [([TyVar], [TyVar])], [TcMethInfo], [ClassATItem])
-> TcM ([Kind], [([TyVar], [TyVar])], [TcMethInfo], [ClassATItem])
forall (m :: * -> *) a. Monad m => a -> m a
return ([Kind]
ctxt, [([TyVar], [TyVar])]
fds, [TcMethInfo]
sig_stuff, [ClassATItem]
at_stuff) }

       -- The solveEqualities will report errors for any
       -- unsolved equalities, so these zonks should not encounter
       -- any unfilled coercion variables unless there is such an error
       -- The zonk also squeeze out the TcTyCons, and converts
       -- Skolems to tyvars.
       ; ZonkEnv
ze        <- TcM ZonkEnv
emptyZonkEnv
       ; [Kind]
ctxt      <- ZonkEnv -> [Kind] -> TcM [Kind]
zonkTcTypesToTypesX ZonkEnv
ze [Kind]
ctxt
       ; [TcMethInfo]
sig_stuff <- (TcMethInfo -> IOEnv (Env TcGblEnv TcLclEnv) TcMethInfo)
-> [TcMethInfo] -> TcM [TcMethInfo]
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
mapM (ZonkEnv -> TcMethInfo -> IOEnv (Env TcGblEnv TcLclEnv) TcMethInfo
zonkTcMethInfoToMethInfoX ZonkEnv
ze) [TcMethInfo]
sig_stuff
         -- ToDo: do we need to zonk at_stuff?

       -- TODO: Allow us to distinguish between abstract class,
       -- and concrete class with no methods (maybe by
       -- specifying a trailing where or not

       ; ClassMinimalDef
mindef <- Name -> [LSig GhcRn] -> [TcMethInfo] -> TcM ClassMinimalDef
tcClassMinimalDef Name
class_name [LSig GhcRn]
sigs [TcMethInfo]
sig_stuff
       ; Bool
is_boot <- TcRn Bool
tcIsHsBootOrSig
       ; let body :: Maybe ([Kind], [ClassATItem], [TcMethInfo], ClassMinimalDef)
body | Bool
is_boot, [Kind] -> Bool
forall (t :: * -> *) a. Foldable t => t a -> Bool
null [Kind]
ctxt, [ClassATItem] -> Bool
forall (t :: * -> *) a. Foldable t => t a -> Bool
null [ClassATItem]
at_stuff, [TcMethInfo] -> Bool
forall (t :: * -> *) a. Foldable t => t a -> Bool
null [TcMethInfo]
sig_stuff
                  = Maybe ([Kind], [ClassATItem], [TcMethInfo], ClassMinimalDef)
forall a. Maybe a
Nothing
                  | Bool
otherwise
                  = ([Kind], [ClassATItem], [TcMethInfo], ClassMinimalDef)
-> Maybe ([Kind], [ClassATItem], [TcMethInfo], ClassMinimalDef)
forall a. a -> Maybe a
Just ([Kind]
ctxt, [ClassATItem]
at_stuff, [TcMethInfo]
sig_stuff, ClassMinimalDef
mindef)

       ; Class
clas <- Name
-> [TyConBinder]
-> [Role]
-> [([TyVar], [TyVar])]
-> Maybe ([Kind], [ClassATItem], [TcMethInfo], ClassMinimalDef)
-> TcM Class
forall m n.
Name
-> [TyConBinder]
-> [Role]
-> [([TyVar], [TyVar])]
-> Maybe ([Kind], [ClassATItem], [TcMethInfo], ClassMinimalDef)
-> TcRnIf m n Class
buildClass Name
class_name [TyConBinder]
binders [Role]
roles [([TyVar], [TyVar])]
fds Maybe ([Kind], [ClassATItem], [TcMethInfo], ClassMinimalDef)
body
       ; String -> SDoc -> TcRn ()
traceTc "tcClassDecl" ([Located (FunDep (Located Name))] -> SDoc
forall a. Outputable a => a -> SDoc
ppr [Located (FunDep (Located Name))]
[LHsFunDep GhcRn]
fundeps SDoc -> SDoc -> SDoc
$$ [TyConBinder] -> SDoc
forall a. Outputable a => a -> SDoc
ppr [TyConBinder]
binders SDoc -> SDoc -> SDoc
$$
                                [([TyVar], [TyVar])] -> SDoc
forall a. Outputable a => a -> SDoc
ppr [([TyVar], [TyVar])]
fds)
       ; Class -> TcM Class
forall (m :: * -> *) a. Monad m => a -> m a
return Class
clas }
  where
    tc_fundep :: (t a, t a) -> IOEnv (Env TcGblEnv TcLclEnv) (t TyVar, t TyVar)
tc_fundep (tvs1 :: t a
tvs1, tvs2 :: t a
tvs2) = do { t TyVar
tvs1' <- (a -> IOEnv (Env TcGblEnv TcLclEnv) TyVar)
-> t a -> IOEnv (Env TcGblEnv TcLclEnv) (t TyVar)
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
mapM (Name -> IOEnv (Env TcGblEnv TcLclEnv) TyVar
tcLookupTyVar (Name -> IOEnv (Env TcGblEnv TcLclEnv) TyVar)
-> (a -> Name) -> a -> IOEnv (Env TcGblEnv TcLclEnv) TyVar
forall b c a. (b -> c) -> (a -> b) -> a -> c
. a -> Name
forall a. HasSrcSpan a => a -> SrcSpanLess a
unLoc) t a
tvs1 ;
                                ; t TyVar
tvs2' <- (a -> IOEnv (Env TcGblEnv TcLclEnv) TyVar)
-> t a -> IOEnv (Env TcGblEnv TcLclEnv) (t TyVar)
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
mapM (Name -> IOEnv (Env TcGblEnv TcLclEnv) TyVar
tcLookupTyVar (Name -> IOEnv (Env TcGblEnv TcLclEnv) TyVar)
-> (a -> Name) -> a -> IOEnv (Env TcGblEnv TcLclEnv) TyVar
forall b c a. (b -> c) -> (a -> b) -> a -> c
. a -> Name
forall a. HasSrcSpan a => a -> SrcSpanLess a
unLoc) t a
tvs2 ;
                                ; (t TyVar, t TyVar)
-> IOEnv (Env TcGblEnv TcLclEnv) (t TyVar, t TyVar)
forall (m :: * -> *) a. Monad m => a -> m a
return (t TyVar
tvs1', t TyVar
tvs2') }


{- Note [Associated type defaults]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The following is an example of associated type defaults:
             class C a where
               data D a

               type F a b :: *
               type F a b = [a]        -- Default

Note that we can get default definitions only for type families, not data
families.
-}

tcClassATs :: Name                   -- The class name (not knot-tied)
           -> Class                  -- The class parent of this associated type
           -> [LFamilyDecl GhcRn]    -- Associated types.
           -> [LTyFamDefltEqn GhcRn] -- Associated type defaults.
           -> TcM [ClassATItem]
tcClassATs :: Name
-> Class
-> [LFamilyDecl GhcRn]
-> [LTyFamDefltEqn GhcRn]
-> TcM [ClassATItem]
tcClassATs class_name :: Name
class_name cls :: Class
cls ats :: [LFamilyDecl GhcRn]
ats at_defs :: [LTyFamDefltEqn GhcRn]
at_defs
  = do {  -- Complain about associated type defaults for non associated-types
         [IOEnv (Env TcGblEnv TcLclEnv) Any] -> TcRn ()
forall (t :: * -> *) (m :: * -> *) a.
(Foldable t, Monad m) =>
t (m a) -> m ()
sequence_ [ SDoc -> IOEnv (Env TcGblEnv TcLclEnv) Any
forall a. SDoc -> TcM a
failWithTc (Name -> Name -> SDoc
badATErr Name
class_name Name
n)
                   | Name
n <- (LTyFamDefltEqn GhcRn -> Name) -> [LTyFamDefltEqn GhcRn] -> [Name]
forall a b. (a -> b) -> [a] -> [b]
map LTyFamDefltEqn GhcRn -> Name
at_def_tycon [LTyFamDefltEqn GhcRn]
at_defs
                   , Bool -> Bool
not (Name
n Name -> NameSet -> Bool
`elemNameSet` NameSet
at_names) ]
       ; (LFamilyDecl GhcRn -> IOEnv (Env TcGblEnv TcLclEnv) ClassATItem)
-> [LFamilyDecl GhcRn] -> TcM [ClassATItem]
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
mapM LFamilyDecl GhcRn -> IOEnv (Env TcGblEnv TcLclEnv) ClassATItem
tc_at [LFamilyDecl GhcRn]
ats }
  where
    at_def_tycon :: LTyFamDefltEqn GhcRn -> Name
    at_def_tycon :: LTyFamDefltEqn GhcRn -> Name
at_def_tycon (LTyFamDefltEqn GhcRn
-> Located (SrcSpanLess (LTyFamDefltEqn GhcRn))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L _ eqn :: SrcSpanLess (LTyFamDefltEqn GhcRn)
eqn) = Located Name -> SrcSpanLess (Located Name)
forall a. HasSrcSpan a => a -> SrcSpanLess a
unLoc (FamEqn GhcRn (LHsQTyVars GhcRn) (LHsKind GhcRn)
-> GenLocated SrcSpan (IdP GhcRn)
forall pass pats rhs. FamEqn pass pats rhs -> Located (IdP pass)
feqn_tycon SrcSpanLess (LTyFamDefltEqn GhcRn)
FamEqn GhcRn (LHsQTyVars GhcRn) (LHsKind GhcRn)
eqn)

    at_fam_name :: LFamilyDecl GhcRn -> Name
    at_fam_name :: LFamilyDecl GhcRn -> Name
at_fam_name (LFamilyDecl GhcRn -> Located (SrcSpanLess (LFamilyDecl GhcRn))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L _ decl :: SrcSpanLess (LFamilyDecl GhcRn)
decl) = Located Name -> SrcSpanLess (Located Name)
forall a. HasSrcSpan a => a -> SrcSpanLess a
unLoc (FamilyDecl GhcRn -> GenLocated SrcSpan (IdP GhcRn)
forall pass. FamilyDecl pass -> Located (IdP pass)
fdLName SrcSpanLess (LFamilyDecl GhcRn)
FamilyDecl GhcRn
decl)

    at_names :: NameSet
at_names = [Name] -> NameSet
mkNameSet ((LFamilyDecl GhcRn -> Name) -> [LFamilyDecl GhcRn] -> [Name]
forall a b. (a -> b) -> [a] -> [b]
map LFamilyDecl GhcRn -> Name
at_fam_name [LFamilyDecl GhcRn]
ats)

    at_defs_map :: NameEnv [LTyFamDefltEqn GhcRn]
    -- Maps an AT in 'ats' to a list of all its default defs in 'at_defs'
    at_defs_map :: NameEnv [LTyFamDefltEqn GhcRn]
at_defs_map = (LTyFamDefltEqn GhcRn
 -> NameEnv [LTyFamDefltEqn GhcRn]
 -> NameEnv [LTyFamDefltEqn GhcRn])
-> NameEnv [LTyFamDefltEqn GhcRn]
-> [LTyFamDefltEqn GhcRn]
-> NameEnv [LTyFamDefltEqn GhcRn]
forall (t :: * -> *) a b.
Foldable t =>
(a -> b -> b) -> b -> t a -> b
foldr (\at_def :: LTyFamDefltEqn GhcRn
at_def nenv :: NameEnv [LTyFamDefltEqn GhcRn]
nenv -> ([LTyFamDefltEqn GhcRn]
 -> [LTyFamDefltEqn GhcRn] -> [LTyFamDefltEqn GhcRn])
-> NameEnv [LTyFamDefltEqn GhcRn]
-> Name
-> [LTyFamDefltEqn GhcRn]
-> NameEnv [LTyFamDefltEqn GhcRn]
forall a. (a -> a -> a) -> NameEnv a -> Name -> a -> NameEnv a
extendNameEnv_C [LTyFamDefltEqn GhcRn]
-> [LTyFamDefltEqn GhcRn] -> [LTyFamDefltEqn GhcRn]
forall a. [a] -> [a] -> [a]
(++) NameEnv [LTyFamDefltEqn GhcRn]
nenv
                                          (LTyFamDefltEqn GhcRn -> Name
at_def_tycon LTyFamDefltEqn GhcRn
at_def) [LTyFamDefltEqn GhcRn
at_def])
                        NameEnv [LTyFamDefltEqn GhcRn]
forall a. NameEnv a
emptyNameEnv [LTyFamDefltEqn GhcRn]
at_defs

    tc_at :: LFamilyDecl GhcRn -> IOEnv (Env TcGblEnv TcLclEnv) ClassATItem
tc_at at :: LFamilyDecl GhcRn
at = do { TyCon
fam_tc <- (SrcSpanLess (LFamilyDecl GhcRn)
 -> IOEnv (Env TcGblEnv TcLclEnv) TyCon)
-> LFamilyDecl GhcRn -> IOEnv (Env TcGblEnv TcLclEnv) TyCon
forall a b. HasSrcSpan a => (SrcSpanLess a -> TcM b) -> a -> TcM b
addLocM (Maybe Class
-> FamilyDecl GhcRn -> IOEnv (Env TcGblEnv TcLclEnv) TyCon
tcFamDecl1 (Class -> Maybe Class
forall a. a -> Maybe a
Just Class
cls)) LFamilyDecl GhcRn
at
                  ; let at_defs :: [LTyFamDefltEqn GhcRn]
at_defs = NameEnv [LTyFamDefltEqn GhcRn]
-> Name -> Maybe [LTyFamDefltEqn GhcRn]
forall a. NameEnv a -> Name -> Maybe a
lookupNameEnv NameEnv [LTyFamDefltEqn GhcRn]
at_defs_map (LFamilyDecl GhcRn -> Name
at_fam_name LFamilyDecl GhcRn
at)
                                  Maybe [LTyFamDefltEqn GhcRn]
-> [LTyFamDefltEqn GhcRn] -> [LTyFamDefltEqn GhcRn]
forall a. Maybe a -> a -> a
`orElse` []
                  ; Maybe (Kind, SrcSpan)
atd <- TyCon -> [LTyFamDefltEqn GhcRn] -> TcM (Maybe (Kind, SrcSpan))
tcDefaultAssocDecl TyCon
fam_tc [LTyFamDefltEqn GhcRn]
at_defs
                  ; ClassATItem -> IOEnv (Env TcGblEnv TcLclEnv) ClassATItem
forall (m :: * -> *) a. Monad m => a -> m a
return (TyCon -> Maybe (Kind, SrcSpan) -> ClassATItem
ATI TyCon
fam_tc Maybe (Kind, SrcSpan)
atd) }

-------------------------
tcDefaultAssocDecl :: TyCon                    -- ^ Family TyCon (not knot-tied)
                   -> [LTyFamDefltEqn GhcRn]        -- ^ Defaults
                   -> TcM (Maybe (KnotTied Type, SrcSpan))   -- ^ Type checked RHS
tcDefaultAssocDecl :: TyCon -> [LTyFamDefltEqn GhcRn] -> TcM (Maybe (Kind, SrcSpan))
tcDefaultAssocDecl _ []
  = Maybe (Kind, SrcSpan) -> TcM (Maybe (Kind, SrcSpan))
forall (m :: * -> *) a. Monad m => a -> m a
return Maybe (Kind, SrcSpan)
forall a. Maybe a
Nothing  -- No default declaration

tcDefaultAssocDecl _ (d1 :: LTyFamDefltEqn GhcRn
d1:_:_)
  = SDoc -> TcM (Maybe (Kind, SrcSpan))
forall a. SDoc -> TcM a
failWithTc (String -> SDoc
text "More than one default declaration for"
                SDoc -> SDoc -> SDoc
<+> Located Name -> SDoc
forall a. Outputable a => a -> SDoc
ppr (FamEqn GhcRn (LHsQTyVars GhcRn) (LHsKind GhcRn)
-> GenLocated SrcSpan (IdP GhcRn)
forall pass pats rhs. FamEqn pass pats rhs -> Located (IdP pass)
feqn_tycon (LTyFamDefltEqn GhcRn -> SrcSpanLess (LTyFamDefltEqn GhcRn)
forall a. HasSrcSpan a => a -> SrcSpanLess a
unLoc LTyFamDefltEqn GhcRn
d1)))

tcDefaultAssocDecl fam_tc :: TyCon
fam_tc [LTyFamDefltEqn GhcRn
-> Located (SrcSpanLess (LTyFamDefltEqn GhcRn))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L loc :: SrcSpan
loc (FamEqn { feqn_tycon = L _ tc_name
                                             , feqn_pats = hs_tvs
                                             , feqn_rhs = hs_rhs_ty })]
  | HsQTvs { hsq_ext :: forall pass. LHsQTyVars pass -> XHsQTvs pass
hsq_ext = HsQTvsRn { hsq_implicit = imp_vars}
           , hsq_explicit :: forall pass. LHsQTyVars pass -> [LHsTyVarBndr pass]
hsq_explicit = [LHsTyVarBndr GhcRn]
exp_vars } <- LHsQTyVars GhcRn
hs_tvs
  = -- See Note [Type-checking default assoc decls]
    SrcSpan
-> TcM (Maybe (Kind, SrcSpan)) -> TcM (Maybe (Kind, SrcSpan))
forall a. SrcSpan -> TcRn a -> TcRn a
setSrcSpan SrcSpan
loc (TcM (Maybe (Kind, SrcSpan)) -> TcM (Maybe (Kind, SrcSpan)))
-> TcM (Maybe (Kind, SrcSpan)) -> TcM (Maybe (Kind, SrcSpan))
forall a b. (a -> b) -> a -> b
$
    SDoc
-> Name
-> TcM (Maybe (Kind, SrcSpan))
-> TcM (Maybe (Kind, SrcSpan))
forall a. SDoc -> Name -> TcM a -> TcM a
tcAddFamInstCtxt (String -> SDoc
text "default type instance") Name
IdP GhcRn
tc_name (TcM (Maybe (Kind, SrcSpan)) -> TcM (Maybe (Kind, SrcSpan)))
-> TcM (Maybe (Kind, SrcSpan)) -> TcM (Maybe (Kind, SrcSpan))
forall a b. (a -> b) -> a -> b
$
    do { String -> SDoc -> TcRn ()
traceTc "tcDefaultAssocDecl" (Name -> SDoc
forall a. Outputable a => a -> SDoc
ppr Name
IdP GhcRn
tc_name)
       ; let fam_tc_name :: Name
fam_tc_name = TyCon -> Name
tyConName TyCon
fam_tc
             fam_arity :: Int
fam_arity = [TyVar] -> Int
forall (t :: * -> *) a. Foldable t => t a -> Int
length (TyCon -> [TyVar]
tyConVisibleTyVars TyCon
fam_tc)

       -- Kind of family check
       ; ASSERT( fam_tc_name == tc_name )
         Bool -> SDoc -> TcRn ()
checkTc (TyCon -> Bool
isTypeFamilyTyCon TyCon
fam_tc) (TyCon -> SDoc
wrongKindOfFamily TyCon
fam_tc)

       -- Arity check
       ; Bool -> SDoc -> TcRn ()
checkTc ([LHsTyVarBndr GhcRn]
exp_vars [LHsTyVarBndr GhcRn] -> Int -> Bool
forall a. [a] -> Int -> Bool
`lengthIs` Int
fam_arity)
                 (Int -> SDoc
wrongNumberOfParmsErr Int
fam_arity)

       -- Typecheck RHS
       ; let hs_pats :: [HsArg (LHsKind GhcRn) (LHsKind GhcRn)]
hs_pats = (LHsTyVarBndr GhcRn -> HsArg (LHsKind GhcRn) (LHsKind GhcRn))
-> [LHsTyVarBndr GhcRn] -> [HsArg (LHsKind GhcRn) (LHsKind GhcRn)]
forall a b. (a -> b) -> [a] -> [b]
map (LHsKind GhcRn -> HsArg (LHsKind GhcRn) (LHsKind GhcRn)
forall tm ty. tm -> HsArg tm ty
HsValArg (LHsKind GhcRn -> HsArg (LHsKind GhcRn) (LHsKind GhcRn))
-> (LHsTyVarBndr GhcRn -> LHsKind GhcRn)
-> LHsTyVarBndr GhcRn
-> HsArg (LHsKind GhcRn) (LHsKind GhcRn)
forall b c a. (b -> c) -> (a -> b) -> a -> c
. LHsTyVarBndr GhcRn -> LHsKind GhcRn
forall (p :: Pass). LHsTyVarBndr (GhcPass p) -> LHsType (GhcPass p)
hsLTyVarBndrToType) [LHsTyVarBndr GhcRn]
exp_vars

          -- NB: Use tcFamTyPats, not bindTyClTyVars. The latter expects to get
          -- the LHsQTyVars used for declaring a tycon, but the names here
          -- are different.

          -- You might think we should pass in some AssocInstInfo, as we're looking
          -- at an associated type. But this would be wrong, because an associated
          -- type default LHS can mention *different* type variables than the
          -- enclosing class. So it's treated more as a freestanding beast.
       ; (qtvs :: [TyVar]
qtvs, pats :: [Kind]
pats, rhs_ty :: Kind
rhs_ty) <- TyCon
-> AssocInstInfo
-> [Name]
-> [LHsTyVarBndr GhcRn]
-> [HsArg (LHsKind GhcRn) (LHsKind GhcRn)]
-> LHsKind GhcRn
-> TcM ([TyVar], [Kind], Kind)
tcTyFamInstEqnGuts TyCon
fam_tc AssocInstInfo
NotAssociated
                                                    [Name]
imp_vars [LHsTyVarBndr GhcRn]
exp_vars
                                                    [HsArg (LHsKind GhcRn) (LHsKind GhcRn)]
hs_pats LHsKind GhcRn
hs_rhs_ty

         -- See Note [Type-checking default assoc decls]
       ; String -> SDoc -> TcRn ()
traceTc "tcDefault" ([SDoc] -> SDoc
vcat [[TyVar] -> SDoc
forall a. Outputable a => a -> SDoc
ppr (TyCon -> [TyVar]
tyConTyVars TyCon
fam_tc), [TyVar] -> SDoc
forall a. Outputable a => a -> SDoc
ppr [TyVar]
qtvs, [Kind] -> SDoc
forall a. Outputable a => a -> SDoc
ppr [Kind]
pats])
       ; case [Kind] -> [Kind] -> Maybe TCvSubst
tcMatchTys [Kind]
pats ([TyVar] -> [Kind]
mkTyVarTys (TyCon -> [TyVar]
tyConTyVars TyCon
fam_tc)) of
           Just subst :: TCvSubst
subst -> Maybe (Kind, SrcSpan) -> TcM (Maybe (Kind, SrcSpan))
forall (m :: * -> *) a. Monad m => a -> m a
return ((Kind, SrcSpan) -> Maybe (Kind, SrcSpan)
forall a. a -> Maybe a
Just (TCvSubst -> Kind -> Kind
substTyUnchecked TCvSubst
subst Kind
rhs_ty, SrcSpan
loc) )
           Nothing    -> SDoc -> TcM (Maybe (Kind, SrcSpan))
forall a. SDoc -> TcM a
failWithTc (TyCon -> SDoc
defaultAssocKindErr TyCon
fam_tc)
           -- We check for well-formedness and validity later,
           -- in checkValidClass
     }
tcDefaultAssocDecl _ [LTyFamDefltEqn GhcRn
-> Located (SrcSpanLess (LTyFamDefltEqn GhcRn))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L _ (XFamEqn _)] = String -> TcM (Maybe (Kind, SrcSpan))
forall a. String -> a
panic "tcDefaultAssocDecl"
tcDefaultAssocDecl _ [LTyFamDefltEqn GhcRn
-> Located (SrcSpanLess (LTyFamDefltEqn GhcRn))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L _ (FamEqn _ _ _ (XLHsQTyVars _) _ _)]
  = String -> TcM (Maybe (Kind, SrcSpan))
forall a. String -> a
panic "tcDefaultAssocDecl"
tcDefaultAssocDecl _ [_]
  = String -> TcM (Maybe (Kind, SrcSpan))
forall a. String -> a
panic "tcDefaultAssocDecl: Impossible Match" -- due to #15884


{- Note [Type-checking default assoc decls]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Consider this default declaration for an associated type

   class C a where
      type F (a :: k) b :: *
      type F x y = Proxy x -> y

Note that the class variable 'a' doesn't scope over the default assoc
decl (rather oddly I think), and (less oddly) neither does the second
argument 'b' of the associated type 'F', or the kind variable 'k'.
Instead, the default decl is treated more like a top-level type
instance.

However we store the default rhs (Proxy x -> y) in F's TyCon, using
F's own type variables, so we need to convert it to (Proxy a -> b).
We do this by calling tcMatchTys to match them up.  This also ensures
that x's kind matches a's and similarly for y and b.  The error
message isn't great, mind you.  (Trac #11361 was caused by not doing a
proper tcMatchTys here.)

Recall also that the left-hand side of an associated type family
default is always just variables -- no tycons here. Accordingly,
the patterns used in the tcMatchTys won't actually be knot-tied,
even though we're in the knot. This is too delicate for my taste,
but it works.

-}

{- *********************************************************************
*                                                                      *
          Type family declarations
*                                                                      *
********************************************************************* -}

tcFamDecl1 :: Maybe Class -> FamilyDecl GhcRn -> TcM TyCon
tcFamDecl1 :: Maybe Class
-> FamilyDecl GhcRn -> IOEnv (Env TcGblEnv TcLclEnv) TyCon
tcFamDecl1 parent :: Maybe Class
parent (FamilyDecl { fdInfo :: forall pass. FamilyDecl pass -> FamilyInfo pass
fdInfo = FamilyInfo GhcRn
fam_info
                              , fdLName :: forall pass. FamilyDecl pass -> Located (IdP pass)
fdLName = tc_lname :: GenLocated SrcSpan (IdP GhcRn)
tc_lname@(GenLocated SrcSpan (IdP GhcRn)
-> Located (SrcSpanLess (Located Name))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L _ tc_name :: SrcSpanLess (Located Name)
tc_name)
                              , fdResultSig :: forall pass. FamilyDecl pass -> LFamilyResultSig pass
fdResultSig = (LFamilyResultSig GhcRn
-> Located (SrcSpanLess (LFamilyResultSig GhcRn))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L _ sig :: SrcSpanLess (LFamilyResultSig GhcRn)
sig)
                              , fdTyVars :: forall pass. FamilyDecl pass -> LHsQTyVars pass
fdTyVars = LHsQTyVars GhcRn
user_tyvars
                              , fdInjectivityAnn :: forall pass. FamilyDecl pass -> Maybe (LInjectivityAnn pass)
fdInjectivityAnn = Maybe (LInjectivityAnn GhcRn)
inj })
  | FamilyInfo GhcRn
DataFamily <- FamilyInfo GhcRn
fam_info
  = Name
-> ([TyConBinder] -> Kind -> IOEnv (Env TcGblEnv TcLclEnv) TyCon)
-> IOEnv (Env TcGblEnv TcLclEnv) TyCon
forall a. Name -> ([TyConBinder] -> Kind -> TcM a) -> TcM a
bindTyClTyVars Name
SrcSpanLess (Located Name)
tc_name (([TyConBinder] -> Kind -> IOEnv (Env TcGblEnv TcLclEnv) TyCon)
 -> IOEnv (Env TcGblEnv TcLclEnv) TyCon)
-> ([TyConBinder] -> Kind -> IOEnv (Env TcGblEnv TcLclEnv) TyCon)
-> IOEnv (Env TcGblEnv TcLclEnv) TyCon
forall a b. (a -> b) -> a -> b
$ \ binders :: [TyConBinder]
binders res_kind :: Kind
res_kind -> do
  { String -> SDoc -> TcRn ()
traceTc "data family:" (Name -> SDoc
forall a. Outputable a => a -> SDoc
ppr Name
SrcSpanLess (Located Name)
tc_name)
  ; Name -> TcRn ()
checkFamFlag Name
SrcSpanLess (Located Name)
tc_name

  -- Check that the result kind is OK
  -- We allow things like
  --   data family T (a :: Type) :: forall k. k -> Type
  -- We treat T as having arity 1, but result kind forall k. k -> Type
  -- But we want to check that the result kind finishes in
  --   Type or a kind-variable
  -- For the latter, consider
  --   data family D a :: forall k. Type -> k
  ; let (_, final_res_kind :: Kind
final_res_kind) = Kind -> ([TyCoBinder], Kind)
splitPiTys Kind
res_kind
  ; Bool -> SDoc -> TcRn ()
checkTc (Kind -> Bool
tcIsLiftedTypeKind Kind
final_res_kind
             Bool -> Bool -> Bool
|| Maybe (TyVar, CoercionN) -> Bool
forall a. Maybe a -> Bool
isJust (Kind -> Maybe (TyVar, CoercionN)
tcGetCastedTyVar_maybe Kind
final_res_kind))
            (Bool -> Kind -> SDoc
badKindSig Bool
False Kind
res_kind)

  ; Name
tc_rep_name <- Name -> TcRnIf TcGblEnv TcLclEnv Name
forall gbl lcl. Name -> TcRnIf gbl lcl Name
newTyConRepName Name
SrcSpanLess (Located Name)
tc_name
  ; let tycon :: TyCon
tycon = Name
-> [TyConBinder]
-> Kind
-> Maybe Name
-> FamTyConFlav
-> Maybe Class
-> Injectivity
-> TyCon
mkFamilyTyCon Name
SrcSpanLess (Located Name)
tc_name [TyConBinder]
binders
                              Kind
res_kind
                              (FamilyResultSig GhcRn -> Maybe (IdP GhcRn)
forall a. FamilyResultSig a -> Maybe (IdP a)
resultVariableName SrcSpanLess (LFamilyResultSig GhcRn)
FamilyResultSig GhcRn
sig)
                              (Name -> FamTyConFlav
DataFamilyTyCon Name
tc_rep_name)
                              Maybe Class
parent Injectivity
NotInjective
  ; TyCon -> IOEnv (Env TcGblEnv TcLclEnv) TyCon
forall (m :: * -> *) a. Monad m => a -> m a
return TyCon
tycon }

  | FamilyInfo GhcRn
OpenTypeFamily <- FamilyInfo GhcRn
fam_info
  = Name
-> ([TyConBinder] -> Kind -> IOEnv (Env TcGblEnv TcLclEnv) TyCon)
-> IOEnv (Env TcGblEnv TcLclEnv) TyCon
forall a. Name -> ([TyConBinder] -> Kind -> TcM a) -> TcM a
bindTyClTyVars Name
SrcSpanLess (Located Name)
tc_name (([TyConBinder] -> Kind -> IOEnv (Env TcGblEnv TcLclEnv) TyCon)
 -> IOEnv (Env TcGblEnv TcLclEnv) TyCon)
-> ([TyConBinder] -> Kind -> IOEnv (Env TcGblEnv TcLclEnv) TyCon)
-> IOEnv (Env TcGblEnv TcLclEnv) TyCon
forall a b. (a -> b) -> a -> b
$ \ binders :: [TyConBinder]
binders res_kind :: Kind
res_kind -> do
  { String -> SDoc -> TcRn ()
traceTc "open type family:" (Name -> SDoc
forall a. Outputable a => a -> SDoc
ppr Name
SrcSpanLess (Located Name)
tc_name)
  ; Name -> TcRn ()
checkFamFlag Name
SrcSpanLess (Located Name)
tc_name
  ; Injectivity
inj' <- [TyConBinder] -> Maybe (LInjectivityAnn GhcRn) -> TcM Injectivity
tcInjectivity [TyConBinder]
binders Maybe (LInjectivityAnn GhcRn)
inj
  ; let tycon :: TyCon
tycon = Name
-> [TyConBinder]
-> Kind
-> Maybe Name
-> FamTyConFlav
-> Maybe Class
-> Injectivity
-> TyCon
mkFamilyTyCon Name
SrcSpanLess (Located Name)
tc_name [TyConBinder]
binders Kind
res_kind
                               (FamilyResultSig GhcRn -> Maybe (IdP GhcRn)
forall a. FamilyResultSig a -> Maybe (IdP a)
resultVariableName SrcSpanLess (LFamilyResultSig GhcRn)
FamilyResultSig GhcRn
sig) FamTyConFlav
OpenSynFamilyTyCon
                               Maybe Class
parent Injectivity
inj'
  ; TyCon -> IOEnv (Env TcGblEnv TcLclEnv) TyCon
forall (m :: * -> *) a. Monad m => a -> m a
return TyCon
tycon }

  | ClosedTypeFamily mb_eqns :: Maybe [LTyFamInstEqn GhcRn]
mb_eqns <- FamilyInfo GhcRn
fam_info
  = -- Closed type families are a little tricky, because they contain the definition
    -- of both the type family and the equations for a CoAxiom.
    do { String -> SDoc -> TcRn ()
traceTc "Closed type family:" (Name -> SDoc
forall a. Outputable a => a -> SDoc
ppr Name
SrcSpanLess (Located Name)
tc_name)
         -- the variables in the header scope only over the injectivity
         -- declaration but this is not involved here
       ; (inj' :: Injectivity
inj', binders :: [TyConBinder]
binders, res_kind :: Kind
res_kind)
            <- Name
-> ([TyConBinder]
    -> Kind -> TcM (Injectivity, [TyConBinder], Kind))
-> TcM (Injectivity, [TyConBinder], Kind)
forall a. Name -> ([TyConBinder] -> Kind -> TcM a) -> TcM a
bindTyClTyVars Name
SrcSpanLess (Located Name)
tc_name (([TyConBinder] -> Kind -> TcM (Injectivity, [TyConBinder], Kind))
 -> TcM (Injectivity, [TyConBinder], Kind))
-> ([TyConBinder]
    -> Kind -> TcM (Injectivity, [TyConBinder], Kind))
-> TcM (Injectivity, [TyConBinder], Kind)
forall a b. (a -> b) -> a -> b
$ \ binders :: [TyConBinder]
binders res_kind :: Kind
res_kind ->
               do { Injectivity
inj' <- [TyConBinder] -> Maybe (LInjectivityAnn GhcRn) -> TcM Injectivity
tcInjectivity [TyConBinder]
binders Maybe (LInjectivityAnn GhcRn)
inj
                  ; (Injectivity, [TyConBinder], Kind)
-> TcM (Injectivity, [TyConBinder], Kind)
forall (m :: * -> *) a. Monad m => a -> m a
return (Injectivity
inj', [TyConBinder]
binders, Kind
res_kind) }

       ; Name -> TcRn ()
checkFamFlag Name
SrcSpanLess (Located Name)
tc_name -- make sure we have -XTypeFamilies

         -- If Nothing, this is an abstract family in a hs-boot file;
         -- but eqns might be empty in the Just case as well
       ; case Maybe [LTyFamInstEqn GhcRn]
mb_eqns of
           Nothing   ->
               TyCon -> IOEnv (Env TcGblEnv TcLclEnv) TyCon
forall (m :: * -> *) a. Monad m => a -> m a
return (TyCon -> IOEnv (Env TcGblEnv TcLclEnv) TyCon)
-> TyCon -> IOEnv (Env TcGblEnv TcLclEnv) TyCon
forall a b. (a -> b) -> a -> b
$ Name
-> [TyConBinder]
-> Kind
-> Maybe Name
-> FamTyConFlav
-> Maybe Class
-> Injectivity
-> TyCon
mkFamilyTyCon Name
SrcSpanLess (Located Name)
tc_name [TyConBinder]
binders Kind
res_kind
                                      (FamilyResultSig GhcRn -> Maybe (IdP GhcRn)
forall a. FamilyResultSig a -> Maybe (IdP a)
resultVariableName SrcSpanLess (LFamilyResultSig GhcRn)
FamilyResultSig GhcRn
sig)
                                      FamTyConFlav
AbstractClosedSynFamilyTyCon Maybe Class
parent
                                      Injectivity
inj'
           Just eqns :: [LTyFamInstEqn GhcRn]
eqns -> do {

         -- Process the equations, creating CoAxBranches
       ; let tc_fam_tc :: TyCon
tc_fam_tc = Name
-> SDoc
-> [TyConBinder]
-> Kind
-> [(Name, TyVar)]
-> Bool
-> TyConFlavour
-> TyCon
mkTcTyCon Name
SrcSpanLess (Located Name)
tc_name (LHsQTyVars GhcRn -> SDoc
forall a. Outputable a => a -> SDoc
ppr LHsQTyVars GhcRn
user_tyvars) [TyConBinder]
binders Kind
res_kind
                                   [] Bool
False {- this doesn't matter here -}
                                   TyConFlavour
ClosedTypeFamilyFlavour

       ; [KnotTied CoAxBranch]
branches <- (LTyFamInstEqn GhcRn -> TcRn (KnotTied CoAxBranch))
-> [LTyFamInstEqn GhcRn] -> TcRn [KnotTied CoAxBranch]
forall a b. (a -> TcRn b) -> [a] -> TcRn [b]
mapAndReportM (TyCon
-> AssocInstInfo
-> LTyFamInstEqn GhcRn
-> TcRn (KnotTied CoAxBranch)
tcTyFamInstEqn TyCon
tc_fam_tc AssocInstInfo
NotAssociated) [LTyFamInstEqn GhcRn]
eqns
         -- Do not attempt to drop equations dominated by earlier
         -- ones here; in the case of mutual recursion with a data
         -- type, we get a knot-tying failure.  Instead we check
         -- for this afterwards, in TcValidity.checkValidCoAxiom
         -- Example: tc265

         -- Create a CoAxiom, with the correct src location.
       ; Name
co_ax_name <- Located Name -> [[Kind]] -> TcRnIf TcGblEnv TcLclEnv Name
newFamInstAxiomName Located Name
GenLocated SrcSpan (IdP GhcRn)
tc_lname []

       ; let mb_co_ax :: Maybe (CoAxiom Branched)
mb_co_ax
              | [LTyFamInstEqn GhcRn] -> Bool
forall (t :: * -> *) a. Foldable t => t a -> Bool
null [LTyFamInstEqn GhcRn]
eqns = Maybe (CoAxiom Branched)
forall a. Maybe a
Nothing   -- mkBranchedCoAxiom fails on empty list
              | Bool
otherwise = CoAxiom Branched -> Maybe (CoAxiom Branched)
forall a. a -> Maybe a
Just (Name -> TyCon -> [KnotTied CoAxBranch] -> CoAxiom Branched
mkBranchedCoAxiom Name
co_ax_name TyCon
fam_tc [KnotTied CoAxBranch]
branches)

             fam_tc :: TyCon
fam_tc = Name
-> [TyConBinder]
-> Kind
-> Maybe Name
-> FamTyConFlav
-> Maybe Class
-> Injectivity
-> TyCon
mkFamilyTyCon Name
SrcSpanLess (Located Name)
tc_name [TyConBinder]
binders Kind
res_kind (FamilyResultSig GhcRn -> Maybe (IdP GhcRn)
forall a. FamilyResultSig a -> Maybe (IdP a)
resultVariableName SrcSpanLess (LFamilyResultSig GhcRn)
FamilyResultSig GhcRn
sig)
                      (Maybe (CoAxiom Branched) -> FamTyConFlav
ClosedSynFamilyTyCon Maybe (CoAxiom Branched)
mb_co_ax) Maybe Class
parent Injectivity
inj'

         -- We check for instance validity later, when doing validity
         -- checking for the tycon. Exception: checking equations
         -- overlap done by dropDominatedAxioms
       ; TyCon -> IOEnv (Env TcGblEnv TcLclEnv) TyCon
forall (m :: * -> *) a. Monad m => a -> m a
return TyCon
fam_tc } }

  | Bool
otherwise = String -> IOEnv (Env TcGblEnv TcLclEnv) TyCon
forall a. String -> a
panic "tcFamInst1"  -- Silence pattern-exhaustiveness checker
tcFamDecl1 _ (XFamilyDecl _) = String -> IOEnv (Env TcGblEnv TcLclEnv) TyCon
forall a. String -> a
panic "tcFamDecl1"

-- | Maybe return a list of Bools that say whether a type family was declared
-- injective in the corresponding type arguments. Length of the list is equal to
-- the number of arguments (including implicit kind/coercion arguments).
-- True on position
-- N means that a function is injective in its Nth argument. False means it is
-- not.
tcInjectivity :: [TyConBinder] -> Maybe (LInjectivityAnn GhcRn)
              -> TcM Injectivity
tcInjectivity :: [TyConBinder] -> Maybe (LInjectivityAnn GhcRn) -> TcM Injectivity
tcInjectivity _ Nothing
  = Injectivity -> TcM Injectivity
forall (m :: * -> *) a. Monad m => a -> m a
return Injectivity
NotInjective

  -- User provided an injectivity annotation, so for each tyvar argument we
  -- check whether a type family was declared injective in that argument. We
  -- return a list of Bools, where True means that corresponding type variable
  -- was mentioned in lInjNames (type family is injective in that argument) and
  -- False means that it was not mentioned in lInjNames (type family is not
  -- injective in that type variable). We also extend injectivity information to
  -- kind variables, so if a user declares:
  --
  --   type family F (a :: k1) (b :: k2) = (r :: k3) | r -> a
  --
  -- then we mark both `a` and `k1` as injective.
  -- NB: the return kind is considered to be *input* argument to a type family.
  -- Since injectivity allows to infer input arguments from the result in theory
  -- we should always mark the result kind variable (`k3` in this example) as
  -- injective.  The reason is that result type has always an assigned kind and
  -- therefore we can always infer the result kind if we know the result type.
  -- But this does not seem to be useful in any way so we don't do it.  (Another
  -- reason is that the implementation would not be straightforward.)
tcInjectivity tcbs :: [TyConBinder]
tcbs (Just (LInjectivityAnn GhcRn
-> Located (SrcSpanLess (LInjectivityAnn GhcRn))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L loc :: SrcSpan
loc (InjectivityAnn _ lInjNames)))
  = SrcSpan -> TcM Injectivity -> TcM Injectivity
forall a. SrcSpan -> TcRn a -> TcRn a
setSrcSpan SrcSpan
loc (TcM Injectivity -> TcM Injectivity)
-> TcM Injectivity -> TcM Injectivity
forall a b. (a -> b) -> a -> b
$
    do { let tvs :: [TyVar]
tvs = [TyConBinder] -> [TyVar]
forall tv argf. [VarBndr tv argf] -> [tv]
binderVars [TyConBinder]
tcbs
       ; DynFlags
dflags <- IOEnv (Env TcGblEnv TcLclEnv) DynFlags
forall (m :: * -> *). HasDynFlags m => m DynFlags
getDynFlags
       ; Bool -> SDoc -> TcRn ()
checkTc (Extension -> DynFlags -> Bool
xopt Extension
LangExt.TypeFamilyDependencies DynFlags
dflags)
                 (String -> SDoc
text "Illegal injectivity annotation" SDoc -> SDoc -> SDoc
$$
                  String -> SDoc
text "Use TypeFamilyDependencies to allow this")
       ; [TyVar]
inj_tvs <- (Located Name -> IOEnv (Env TcGblEnv TcLclEnv) TyVar)
-> [Located Name] -> IOEnv (Env TcGblEnv TcLclEnv) [TyVar]
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
mapM (Name -> IOEnv (Env TcGblEnv TcLclEnv) TyVar
tcLookupTyVar (Name -> IOEnv (Env TcGblEnv TcLclEnv) TyVar)
-> (Located Name -> Name)
-> Located Name
-> IOEnv (Env TcGblEnv TcLclEnv) TyVar
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Located Name -> Name
forall a. HasSrcSpan a => a -> SrcSpanLess a
unLoc) [Located Name]
[GenLocated SrcSpan (IdP GhcRn)]
lInjNames
       ; [TyVar]
inj_tvs <- (TyVar -> IOEnv (Env TcGblEnv TcLclEnv) TyVar)
-> [TyVar] -> IOEnv (Env TcGblEnv TcLclEnv) [TyVar]
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
mapM HasDebugCallStack => TyVar -> IOEnv (Env TcGblEnv TcLclEnv) TyVar
TyVar -> IOEnv (Env TcGblEnv TcLclEnv) TyVar
zonkTcTyVarToTyVar [TyVar]
inj_tvs -- zonk the kinds
       ; let inj_ktvs :: TcTyCoVarSet
inj_ktvs = (TyVar -> Bool) -> TcTyCoVarSet -> TcTyCoVarSet
filterVarSet TyVar -> Bool
isTyVar (TcTyCoVarSet -> TcTyCoVarSet) -> TcTyCoVarSet -> TcTyCoVarSet
forall a b. (a -> b) -> a -> b
$  -- no injective coercion vars
                        TcTyCoVarSet -> TcTyCoVarSet
closeOverKinds ([TyVar] -> TcTyCoVarSet
mkVarSet [TyVar]
inj_tvs)
       ; let inj_bools :: [Bool]
inj_bools = (TyVar -> Bool) -> [TyVar] -> [Bool]
forall a b. (a -> b) -> [a] -> [b]
map (TyVar -> TcTyCoVarSet -> Bool
`elemVarSet` TcTyCoVarSet
inj_ktvs) [TyVar]
tvs
       ; String -> SDoc -> TcRn ()
traceTc "tcInjectivity" ([SDoc] -> SDoc
vcat [ [TyVar] -> SDoc
forall a. Outputable a => a -> SDoc
ppr [TyVar]
tvs, [Located Name] -> SDoc
forall a. Outputable a => a -> SDoc
ppr [Located Name]
[GenLocated SrcSpan (IdP GhcRn)]
lInjNames, [TyVar] -> SDoc
forall a. Outputable a => a -> SDoc
ppr [TyVar]
inj_tvs
                                       , TcTyCoVarSet -> SDoc
forall a. Outputable a => a -> SDoc
ppr TcTyCoVarSet
inj_ktvs, [Bool] -> SDoc
forall a. Outputable a => a -> SDoc
ppr [Bool]
inj_bools ])
       ; Injectivity -> TcM Injectivity
forall (m :: * -> *) a. Monad m => a -> m a
return (Injectivity -> TcM Injectivity) -> Injectivity -> TcM Injectivity
forall a b. (a -> b) -> a -> b
$ [Bool] -> Injectivity
Injective [Bool]
inj_bools }

tcTySynRhs :: RolesInfo
           -> Name
           -> [TyConBinder] -> Kind
           -> LHsType GhcRn -> TcM TyCon
tcTySynRhs :: (Name -> [Role])
-> Name
-> [TyConBinder]
-> Kind
-> LHsKind GhcRn
-> IOEnv (Env TcGblEnv TcLclEnv) TyCon
tcTySynRhs roles_info :: Name -> [Role]
roles_info tc_name :: Name
tc_name binders :: [TyConBinder]
binders res_kind :: Kind
res_kind hs_ty :: LHsKind GhcRn
hs_ty
  = do { TcLclEnv
env <- TcRnIf TcGblEnv TcLclEnv TcLclEnv
forall gbl lcl. TcRnIf gbl lcl lcl
getLclEnv
       ; String -> SDoc -> TcRn ()
traceTc "tc-syn" (Name -> SDoc
forall a. Outputable a => a -> SDoc
ppr Name
tc_name SDoc -> SDoc -> SDoc
$$ NameEnv TcTyThing -> SDoc
forall a. Outputable a => a -> SDoc
ppr (TcLclEnv -> NameEnv TcTyThing
tcl_env TcLclEnv
env))
       ; Kind
rhs_ty <- TcM Kind -> TcM Kind
forall r. TcM r -> TcM r
pushTcLevelM_   (TcM Kind -> TcM Kind) -> TcM Kind -> TcM Kind
forall a b. (a -> b) -> a -> b
$
                   TcM Kind -> TcM Kind
forall r. TcM r -> TcM r
solveEqualities (TcM Kind -> TcM Kind) -> TcM Kind -> TcM Kind
forall a b. (a -> b) -> a -> b
$
                   LHsKind GhcRn -> Kind -> TcM Kind
tcCheckLHsType LHsKind GhcRn
hs_ty Kind
res_kind
       ; Kind
rhs_ty <- Kind -> TcM Kind
zonkTcTypeToType Kind
rhs_ty
       ; let roles :: [Role]
roles = Name -> [Role]
roles_info Name
tc_name
             tycon :: TyCon
tycon = Name -> [TyConBinder] -> Kind -> [Role] -> Kind -> TyCon
buildSynTyCon Name
tc_name [TyConBinder]
binders Kind
res_kind [Role]
roles Kind
rhs_ty
       ; TyCon -> IOEnv (Env TcGblEnv TcLclEnv) TyCon
forall (m :: * -> *) a. Monad m => a -> m a
return TyCon
tycon }

tcDataDefn :: RolesInfo -> Name
           -> [TyConBinder] -> Kind
           -> HsDataDefn GhcRn -> TcM TyCon
  -- NB: not used for newtype/data instances (whether associated or not)
tcDataDefn :: (Name -> [Role])
-> Name
-> [TyConBinder]
-> Kind
-> HsDataDefn GhcRn
-> IOEnv (Env TcGblEnv TcLclEnv) TyCon
tcDataDefn roles_info :: Name -> [Role]
roles_info
           tc_name :: Name
tc_name tycon_binders :: [TyConBinder]
tycon_binders res_kind :: Kind
res_kind
           (HsDataDefn { dd_ND :: forall pass. HsDataDefn pass -> NewOrData
dd_ND = NewOrData
new_or_data, dd_cType :: forall pass. HsDataDefn pass -> Maybe (Located CType)
dd_cType = Maybe (Located CType)
cType
                       , dd_ctxt :: forall pass. HsDataDefn pass -> LHsContext pass
dd_ctxt = LHsContext GhcRn
ctxt
                       , dd_kindSig :: forall pass. HsDataDefn pass -> Maybe (LHsKind pass)
dd_kindSig = Maybe (LHsKind GhcRn)
mb_ksig  -- Already in tc's kind
                                               -- via getInitialKinds
                       , dd_cons :: forall pass. HsDataDefn pass -> [LConDecl pass]
dd_cons = [LConDecl GhcRn]
cons })
 =  do { Bool
gadt_syntax <- Name
-> NewOrData -> LHsContext GhcRn -> [LConDecl GhcRn] -> TcRn Bool
dataDeclChecks Name
tc_name NewOrData
new_or_data LHsContext GhcRn
ctxt [LConDecl GhcRn]
cons

       ; TcGblEnv
tcg_env <- TcRnIf TcGblEnv TcLclEnv TcGblEnv
forall gbl lcl. TcRnIf gbl lcl gbl
getGblEnv
       ; (extra_bndrs :: [TyConBinder]
extra_bndrs, final_res_kind :: Kind
final_res_kind) <- [TyConBinder] -> Kind -> TcM ([TyConBinder], Kind)
etaExpandAlgTyCon [TyConBinder]
tycon_binders Kind
res_kind

       ; let hsc_src :: HscSource
hsc_src = TcGblEnv -> HscSource
tcg_src TcGblEnv
tcg_env
       ; Bool -> TcRn () -> TcRn ()
forall (f :: * -> *). Applicative f => Bool -> f () -> f ()
unless (HscSource -> [LConDecl GhcRn] -> Bool
forall a. HscSource -> [a] -> Bool
mk_permissive_kind HscSource
hsc_src [LConDecl GhcRn]
cons) (TcRn () -> TcRn ()) -> TcRn () -> TcRn ()
forall a b. (a -> b) -> a -> b
$
         Bool -> SDoc -> TcRn ()
checkTc (Kind -> Bool
tcIsLiftedTypeKind Kind
final_res_kind) (Bool -> Kind -> SDoc
badKindSig Bool
True Kind
res_kind)

       ; [Kind]
stupid_tc_theta <- TcM [Kind] -> TcM [Kind]
forall r. TcM r -> TcM r
pushTcLevelM_ (TcM [Kind] -> TcM [Kind]) -> TcM [Kind] -> TcM [Kind]
forall a b. (a -> b) -> a -> b
$ TcM [Kind] -> TcM [Kind]
forall r. TcM r -> TcM r
solveEqualities (TcM [Kind] -> TcM [Kind]) -> TcM [Kind] -> TcM [Kind]
forall a b. (a -> b) -> a -> b
$ LHsContext GhcRn -> TcM [Kind]
tcHsContext LHsContext GhcRn
ctxt
       ; [Kind]
stupid_theta    <- [Kind] -> TcM [Kind]
zonkTcTypesToTypes [Kind]
stupid_tc_theta
       ; Bool
kind_signatures <- Extension -> TcRn Bool
forall gbl lcl. Extension -> TcRnIf gbl lcl Bool
xoptM Extension
LangExt.KindSignatures

             -- Check that we don't use kind signatures without Glasgow extensions
       ; Bool -> TcRn () -> TcRn ()
forall (f :: * -> *). Applicative f => Bool -> f () -> f ()
when (Maybe (LHsKind GhcRn) -> Bool
forall a. Maybe a -> Bool
isJust Maybe (LHsKind GhcRn)
mb_ksig) (TcRn () -> TcRn ()) -> TcRn () -> TcRn ()
forall a b. (a -> b) -> a -> b
$
         Bool -> SDoc -> TcRn ()
checkTc (Bool
kind_signatures) (Name -> SDoc
badSigTyDecl Name
tc_name)

       ; TyCon
tycon <- (TyCon -> IOEnv (Env TcGblEnv TcLclEnv) TyCon)
-> IOEnv (Env TcGblEnv TcLclEnv) TyCon
forall a env. (a -> IOEnv env a) -> IOEnv env a
fixM ((TyCon -> IOEnv (Env TcGblEnv TcLclEnv) TyCon)
 -> IOEnv (Env TcGblEnv TcLclEnv) TyCon)
-> (TyCon -> IOEnv (Env TcGblEnv TcLclEnv) TyCon)
-> IOEnv (Env TcGblEnv TcLclEnv) TyCon
forall a b. (a -> b) -> a -> b
$ \ tycon :: TyCon
tycon -> do
             { let final_bndrs :: [TyConBinder]
final_bndrs = [TyConBinder]
tycon_binders [TyConBinder] -> [TyConBinder] -> [TyConBinder]
forall a. [a] -> [a] -> [a]
`chkAppend` [TyConBinder]
extra_bndrs
                   res_ty :: Kind
res_ty      = TyCon -> [Kind] -> Kind
mkTyConApp TyCon
tycon ([TyVar] -> [Kind]
mkTyVarTys ([TyConBinder] -> [TyVar]
forall tv argf. [VarBndr tv argf] -> [tv]
binderVars [TyConBinder]
final_bndrs))
                   roles :: [Role]
roles       = Name -> [Role]
roles_info Name
tc_name

             ; [DataCon]
data_cons <- TyCon -> [TyConBinder] -> Kind -> [LConDecl GhcRn] -> TcM [DataCon]
tcConDecls TyCon
tycon [TyConBinder]
final_bndrs Kind
res_ty [LConDecl GhcRn]
cons
             ; AlgTyConRhs
tc_rhs    <- HscSource
-> TyCon -> [DataCon] -> IOEnv (Env TcGblEnv TcLclEnv) AlgTyConRhs
mk_tc_rhs HscSource
hsc_src TyCon
tycon [DataCon]
data_cons
             ; Name
tc_rep_nm <- Name -> TcRnIf TcGblEnv TcLclEnv Name
forall gbl lcl. Name -> TcRnIf gbl lcl Name
newTyConRepName Name
tc_name
             ; TyCon -> IOEnv (Env TcGblEnv TcLclEnv) TyCon
forall (m :: * -> *) a. Monad m => a -> m a
return (Name
-> [TyConBinder]
-> Kind
-> [Role]
-> Maybe CType
-> [Kind]
-> AlgTyConRhs
-> AlgTyConFlav
-> Bool
-> TyCon
mkAlgTyCon Name
tc_name
                                  [TyConBinder]
final_bndrs
                                  Kind
final_res_kind
                                  [Role]
roles
                                  ((Located CType -> CType) -> Maybe (Located CType) -> Maybe CType
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
fmap Located CType -> CType
forall a. HasSrcSpan a => a -> SrcSpanLess a
unLoc Maybe (Located CType)
cType)
                                  [Kind]
stupid_theta AlgTyConRhs
tc_rhs
                                  (Name -> AlgTyConFlav
VanillaAlgTyCon Name
tc_rep_nm)
                                  Bool
gadt_syntax) }
       ; String -> SDoc -> TcRn ()
traceTc "tcDataDefn" (Name -> SDoc
forall a. Outputable a => a -> SDoc
ppr Name
tc_name SDoc -> SDoc -> SDoc
$$ [TyConBinder] -> SDoc
forall a. Outputable a => a -> SDoc
ppr [TyConBinder]
tycon_binders SDoc -> SDoc -> SDoc
$$ [TyConBinder] -> SDoc
forall a. Outputable a => a -> SDoc
ppr [TyConBinder]
extra_bndrs)
       ; TyCon -> IOEnv (Env TcGblEnv TcLclEnv) TyCon
forall (m :: * -> *) a. Monad m => a -> m a
return TyCon
tycon }
  where
    -- Abstract data types in hsig files can have arbitrary kinds,
    -- because they may be implemented by type synonyms
    -- (which themselves can have arbitrary kinds, not just *)
    mk_permissive_kind :: HscSource -> [a] -> Bool
mk_permissive_kind HsigFile [] = Bool
True
    mk_permissive_kind _ _ = Bool
False

    -- In hs-boot, a 'data' declaration with no constructors
    -- indicates a nominally distinct abstract data type.
    mk_tc_rhs :: HscSource
-> TyCon -> [DataCon] -> IOEnv (Env TcGblEnv TcLclEnv) AlgTyConRhs
mk_tc_rhs HsBootFile _ []
      = AlgTyConRhs -> IOEnv (Env TcGblEnv TcLclEnv) AlgTyConRhs
forall (m :: * -> *) a. Monad m => a -> m a
return AlgTyConRhs
AbstractTyCon

    mk_tc_rhs HsigFile _ [] -- ditto
      = AlgTyConRhs -> IOEnv (Env TcGblEnv TcLclEnv) AlgTyConRhs
forall (m :: * -> *) a. Monad m => a -> m a
return AlgTyConRhs
AbstractTyCon

    mk_tc_rhs _ tycon :: TyCon
tycon data_cons :: [DataCon]
data_cons
      = case NewOrData
new_or_data of
          DataType -> AlgTyConRhs -> IOEnv (Env TcGblEnv TcLclEnv) AlgTyConRhs
forall (m :: * -> *) a. Monad m => a -> m a
return ([DataCon] -> AlgTyConRhs
mkDataTyConRhs [DataCon]
data_cons)
          NewType  -> ASSERT( not (null data_cons) )
                      Name
-> TyCon -> DataCon -> IOEnv (Env TcGblEnv TcLclEnv) AlgTyConRhs
forall m n. Name -> TyCon -> DataCon -> TcRnIf m n AlgTyConRhs
mkNewTyConRhs Name
tc_name TyCon
tycon ([DataCon] -> DataCon
forall a. [a] -> a
head [DataCon]
data_cons)
tcDataDefn _ _ _ _ (XHsDataDefn _) = String -> IOEnv (Env TcGblEnv TcLclEnv) TyCon
forall a. String -> a
panic "tcDataDefn"


-------------------------
kcTyFamInstEqn :: TcTyCon -> LTyFamInstEqn GhcRn -> TcM ()
-- Used for the equations of a closed type family only
-- Not used for data/type instances
kcTyFamInstEqn :: TyCon -> LTyFamInstEqn GhcRn -> TcRn ()
kcTyFamInstEqn tc_fam_tc :: TyCon
tc_fam_tc
    (LTyFamInstEqn GhcRn -> Located (SrcSpanLess (LTyFamInstEqn GhcRn))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L loc :: SrcSpan
loc (HsIB { hsib_ext = imp_vars
                     , hsib_body = FamEqn { feqn_tycon = dL->L _ eqn_tc_name
                                          , feqn_bndrs = mb_expl_bndrs
                                          , feqn_pats  = hs_pats
                                          , feqn_rhs   = hs_rhs_ty }}))
  = SrcSpan -> TcRn () -> TcRn ()
forall a. SrcSpan -> TcRn a -> TcRn a
setSrcSpan SrcSpan
loc (TcRn () -> TcRn ()) -> TcRn () -> TcRn ()
forall a b. (a -> b) -> a -> b
$
    do { String -> SDoc -> TcRn ()
traceTc "kcTyFamInstEqn" ([SDoc] -> SDoc
vcat
           [ String -> SDoc
text "tc_name ="    SDoc -> SDoc -> SDoc
<+> Name -> SDoc
forall a. Outputable a => a -> SDoc
ppr Name
SrcSpanLess (Located Name)
eqn_tc_name
           , String -> SDoc
text "fam_tc ="     SDoc -> SDoc -> SDoc
<+> TyCon -> SDoc
forall a. Outputable a => a -> SDoc
ppr TyCon
tc_fam_tc SDoc -> SDoc -> SDoc
<+> SDoc
dcolon SDoc -> SDoc -> SDoc
<+> Kind -> SDoc
forall a. Outputable a => a -> SDoc
ppr (TyCon -> Kind
tyConKind TyCon
tc_fam_tc)
           , String -> SDoc
text "hsib_vars ="  SDoc -> SDoc -> SDoc
<+> [Name] -> SDoc
forall a. Outputable a => a -> SDoc
ppr [Name]
XHsIB
  GhcRn
  (FamEqn
     GhcRn [HsArg (LHsKind GhcRn) (LHsKind GhcRn)] (LHsKind GhcRn))
imp_vars
           , String -> SDoc
text "feqn_bndrs =" SDoc -> SDoc -> SDoc
<+> Maybe [LHsTyVarBndr GhcRn] -> SDoc
forall a. Outputable a => a -> SDoc
ppr Maybe [LHsTyVarBndr GhcRn]
mb_expl_bndrs
           , String -> SDoc
text "feqn_pats ="  SDoc -> SDoc -> SDoc
<+> [HsArg (LHsKind GhcRn) (LHsKind GhcRn)] -> SDoc
forall a. Outputable a => a -> SDoc
ppr [HsArg (LHsKind GhcRn) (LHsKind GhcRn)]
hs_pats ])
          -- this check reports an arity error instead of a kind error; easier for user
       ; let vis_pats :: Int
vis_pats = [HsArg (LHsKind GhcRn) (LHsKind GhcRn)] -> Int
forall tm ty. [HsArg tm ty] -> Int
numVisibleArgs [HsArg (LHsKind GhcRn) (LHsKind GhcRn)]
hs_pats
       ; Bool -> SDoc -> TcRn ()
checkTc (Int
vis_pats Int -> Int -> Bool
forall a. Eq a => a -> a -> Bool
== Int
vis_arity) (SDoc -> TcRn ()) -> SDoc -> TcRn ()
forall a b. (a -> b) -> a -> b
$
                  Int -> SDoc
wrongNumberOfParmsErr Int
vis_arity
       ; TcM ([TyVar], ([TyVar], Kind)) -> TcRn ()
forall a. TcM a -> TcRn ()
discardResult (TcM ([TyVar], ([TyVar], Kind)) -> TcRn ())
-> TcM ([TyVar], ([TyVar], Kind)) -> TcRn ()
forall a b. (a -> b) -> a -> b
$
         [Name] -> TcM ([TyVar], Kind) -> TcM ([TyVar], ([TyVar], Kind))
forall a. [Name] -> TcM a -> TcM ([TyVar], a)
bindImplicitTKBndrs_Q_Tv [Name]
XHsIB
  GhcRn
  (FamEqn
     GhcRn [HsArg (LHsKind GhcRn) (LHsKind GhcRn)] (LHsKind GhcRn))
imp_vars (TcM ([TyVar], Kind) -> TcM ([TyVar], ([TyVar], Kind)))
-> TcM ([TyVar], Kind) -> TcM ([TyVar], ([TyVar], Kind))
forall a b. (a -> b) -> a -> b
$
         ContextKind
-> [LHsTyVarBndr GhcRn] -> TcM Kind -> TcM ([TyVar], Kind)
forall a.
ContextKind -> [LHsTyVarBndr GhcRn] -> TcM a -> TcM ([TyVar], a)
bindExplicitTKBndrs_Q_Tv ContextKind
AnyKind (Maybe [LHsTyVarBndr GhcRn]
mb_expl_bndrs Maybe [LHsTyVarBndr GhcRn]
-> [LHsTyVarBndr GhcRn] -> [LHsTyVarBndr GhcRn]
forall a. Maybe a -> a -> a
`orElse` []) (TcM Kind -> TcM ([TyVar], Kind))
-> TcM Kind -> TcM ([TyVar], Kind)
forall a b. (a -> b) -> a -> b
$
         do { (_, res_kind :: Kind
res_kind) <- TyCon
-> [HsArg (LHsKind GhcRn) (LHsKind GhcRn)] -> TcM (Kind, Kind)
tcFamTyPats TyCon
tc_fam_tc [HsArg (LHsKind GhcRn) (LHsKind GhcRn)]
hs_pats
            ; LHsKind GhcRn -> Kind -> TcM Kind
tcCheckLHsType LHsKind GhcRn
hs_rhs_ty Kind
res_kind }
             -- Why "_Tv" here?  Consider (Trac #14066
             --  type family Bar x y where
             --      Bar (x :: a) (y :: b) = Int
             --      Bar (x :: c) (y :: d) = Bool
             -- During kind-checkig, a,b,c,d should be TyVarTvs and unify appropriately
    }
  where
    vis_arity :: Int
vis_arity = [TyVar] -> Int
forall (t :: * -> *) a. Foldable t => t a -> Int
length (TyCon -> [TyVar]
tyConVisibleTyVars TyCon
tc_fam_tc)

kcTyFamInstEqn _ (LTyFamInstEqn GhcRn -> Located (SrcSpanLess (LTyFamInstEqn GhcRn))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L _ (XHsImplicitBndrs _)) = String -> TcRn ()
forall a. String -> a
panic "kcTyFamInstEqn"
kcTyFamInstEqn _ (LTyFamInstEqn GhcRn -> Located (SrcSpanLess (LTyFamInstEqn GhcRn))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L _ (HsIB _ (XFamEqn _))) = String -> TcRn ()
forall a. String -> a
panic "kcTyFamInstEqn"
kcTyFamInstEqn _ _ = String -> TcRn ()
forall a. String -> a
panic "kcTyFamInstEqn: Impossible Match" -- due to #15884


--------------------------
tcTyFamInstEqn :: TcTyCon -> AssocInstInfo -> LTyFamInstEqn GhcRn
               -> TcM (KnotTied CoAxBranch)
-- Needs to be here, not in TcInstDcls, because closed families
-- (typechecked here) have TyFamInstEqns

tcTyFamInstEqn :: TyCon
-> AssocInstInfo
-> LTyFamInstEqn GhcRn
-> TcRn (KnotTied CoAxBranch)
tcTyFamInstEqn fam_tc :: TyCon
fam_tc mb_clsinfo :: AssocInstInfo
mb_clsinfo
    (LTyFamInstEqn GhcRn -> Located (SrcSpanLess (LTyFamInstEqn GhcRn))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L loc :: SrcSpan
loc (HsIB { hsib_ext = imp_vars
                 , hsib_body = FamEqn { feqn_tycon  = L _ eqn_tc_name
                                      , feqn_bndrs  = mb_expl_bndrs
                                      , feqn_pats   = hs_pats
                                      , feqn_rhs    = hs_rhs_ty }}))
  = ASSERT( getName fam_tc == eqn_tc_name )
    SrcSpan -> TcRn (KnotTied CoAxBranch) -> TcRn (KnotTied CoAxBranch)
forall a. SrcSpan -> TcRn a -> TcRn a
setSrcSpan SrcSpan
loc (TcRn (KnotTied CoAxBranch) -> TcRn (KnotTied CoAxBranch))
-> TcRn (KnotTied CoAxBranch) -> TcRn (KnotTied CoAxBranch)
forall a b. (a -> b) -> a -> b
$
    do {
       -- First, check the arity of visible arguments
       -- If we wait until validity checking, we'll get kind errors
       -- below when an arity error will be much easier to understand.
       ; let vis_arity :: Int
vis_arity = [TyVar] -> Int
forall (t :: * -> *) a. Foldable t => t a -> Int
length (TyCon -> [TyVar]
tyConVisibleTyVars TyCon
fam_tc)
             vis_pats :: Int
vis_pats  = [HsArg (LHsKind GhcRn) (LHsKind GhcRn)] -> Int
forall tm ty. [HsArg tm ty] -> Int
numVisibleArgs [HsArg (LHsKind GhcRn) (LHsKind GhcRn)]
hs_pats
       ; Bool -> SDoc -> TcRn ()
checkTc (Int
vis_pats Int -> Int -> Bool
forall a. Eq a => a -> a -> Bool
== Int
vis_arity) (SDoc -> TcRn ()) -> SDoc -> TcRn ()
forall a b. (a -> b) -> a -> b
$
         Int -> SDoc
wrongNumberOfParmsErr Int
vis_arity

       ; (qtvs :: [TyVar]
qtvs, pats :: [Kind]
pats, rhs_ty :: Kind
rhs_ty) <- TyCon
-> AssocInstInfo
-> [Name]
-> [LHsTyVarBndr GhcRn]
-> [HsArg (LHsKind GhcRn) (LHsKind GhcRn)]
-> LHsKind GhcRn
-> TcM ([TyVar], [Kind], Kind)
tcTyFamInstEqnGuts TyCon
fam_tc AssocInstInfo
mb_clsinfo
                                      [Name]
XHsIB
  GhcRn
  (FamEqn
     GhcRn [HsArg (LHsKind GhcRn) (LHsKind GhcRn)] (LHsKind GhcRn))
imp_vars (Maybe [LHsTyVarBndr GhcRn]
mb_expl_bndrs Maybe [LHsTyVarBndr GhcRn]
-> [LHsTyVarBndr GhcRn] -> [LHsTyVarBndr GhcRn]
forall a. Maybe a -> a -> a
`orElse` [])
                                      [HsArg (LHsKind GhcRn) (LHsKind GhcRn)]
hs_pats LHsKind GhcRn
hs_rhs_ty

       -- Don't print results they may be knot-tied
       -- (tcFamInstEqnGuts zonks to Type)
       ; KnotTied CoAxBranch -> TcRn (KnotTied CoAxBranch)
forall (m :: * -> *) a. Monad m => a -> m a
return ([TyVar]
-> [TyVar]
-> [TyVar]
-> [Kind]
-> Kind
-> [Role]
-> SrcSpan
-> KnotTied CoAxBranch
mkCoAxBranch [TyVar]
qtvs [] [] [Kind]
pats Kind
rhs_ty
                              ((TyVar -> Role) -> [TyVar] -> [Role]
forall a b. (a -> b) -> [a] -> [b]
map (Role -> TyVar -> Role
forall a b. a -> b -> a
const Role
Nominal) [TyVar]
qtvs)
                              SrcSpan
loc) }

tcTyFamInstEqn _ _ _ = String -> TcRn (KnotTied CoAxBranch)
forall a. String -> a
panic "tcTyFamInstEqn"

{-
Kind check type patterns and kind annotate the embedded type variables.
     type instance F [a] = rhs

 * Here we check that a type instance matches its kind signature, but we do
   not check whether there is a pattern for each type index; the latter
   check is only required for type synonym instances.

Note [Instantiating a family tycon]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
It's possible that kind-checking the result of a family tycon applied to
its patterns will instantiate the tycon further. For example, we might
have

  type family F :: k where
    F = Int
    F = Maybe

After checking (F :: forall k. k) (with no visible patterns), we still need
to instantiate the k. With data family instances, this problem can be even
more intricate, due to Note [Arity of data families] in FamInstEnv. See
indexed-types/should_compile/T12369 for an example.

So, the kind-checker must return the new skolems and args (that is, Type
or (Type -> Type) for the equations above) and the instantiated kind.

Note [Generalising in tcFamTyPatsGuts]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Suppose we have something like
  type instance forall (a::k) b. F t1 t2 = rhs

Then  imp_vars = [k], exp_bndrs = [a::k, b]

We want to quantify over
  * k, a, and b  (all user-specified)
  * and any inferred free kind vars from
      - the kinds of k, a, b
      - the types t1, t2

However, unlike a type signature like
  f :: forall (a::k). blah

we do /not/ care about the Inferred/Specified designation
or order for the final quantified tyvars.  Type-family
instances are not invoked directly in Haskell source code,
so visible type application etc plays no role.

So, the simple thing is
   - gather candiates from [k, a, b] and pats
   - quantify over them

Hence the sligtly mysterious call:
    candidateQTyVarsOfTypes (pats ++ mkTyVarTys scoped_tvs)

Simple, neat, but a little non-obvious!
-}

--------------------------
tcTyFamInstEqnGuts :: TyCon -> AssocInstInfo
                   -> [Name] -> [LHsTyVarBndr GhcRn]  -- Implicit and explicicit binder
                   -> HsTyPats GhcRn                  -- Patterns
                   -> LHsType GhcRn                   -- RHS
                   -> TcM ([TyVar], [TcType], TcType)      -- (tyvars, pats, rhs)
-- Used only for type families, not data families
tcTyFamInstEqnGuts :: TyCon
-> AssocInstInfo
-> [Name]
-> [LHsTyVarBndr GhcRn]
-> [HsArg (LHsKind GhcRn) (LHsKind GhcRn)]
-> LHsKind GhcRn
-> TcM ([TyVar], [Kind], Kind)
tcTyFamInstEqnGuts fam_tc :: TyCon
fam_tc mb_clsinfo :: AssocInstInfo
mb_clsinfo imp_vars :: [Name]
imp_vars exp_bndrs :: [LHsTyVarBndr GhcRn]
exp_bndrs hs_pats :: [HsArg (LHsKind GhcRn) (LHsKind GhcRn)]
hs_pats hs_rhs_ty :: LHsKind GhcRn
hs_rhs_ty
  = do { String -> SDoc -> TcRn ()
traceTc "tcTyFamInstEqnGuts {" ([SDoc] -> SDoc
vcat [ TyCon -> SDoc
forall a. Outputable a => a -> SDoc
ppr TyCon
fam_tc SDoc -> SDoc -> SDoc
<+> [HsArg (LHsKind GhcRn) (LHsKind GhcRn)] -> SDoc
forall a. Outputable a => a -> SDoc
ppr [HsArg (LHsKind GhcRn) (LHsKind GhcRn)]
hs_pats ])

       -- By now, for type families (but not data families) we should
       -- have checked that the number of patterns matches tyConArity

       -- This code is closely related to the code
       -- in TcHsType.kcLHsQTyVars_Cusk
       ; (imp_tvs :: [TyVar]
imp_tvs, (exp_tvs :: [TyVar]
exp_tvs, (lhs_ty :: Kind
lhs_ty, rhs_ty :: Kind
rhs_ty)))
               <- TcM ([TyVar], ([TyVar], (Kind, Kind)))
-> TcM ([TyVar], ([TyVar], (Kind, Kind)))
forall r. TcM r -> TcM r
pushTcLevelM_                                (TcM ([TyVar], ([TyVar], (Kind, Kind)))
 -> TcM ([TyVar], ([TyVar], (Kind, Kind))))
-> TcM ([TyVar], ([TyVar], (Kind, Kind)))
-> TcM ([TyVar], ([TyVar], (Kind, Kind)))
forall a b. (a -> b) -> a -> b
$
                  TcM ([TyVar], ([TyVar], (Kind, Kind)))
-> TcM ([TyVar], ([TyVar], (Kind, Kind)))
forall r. TcM r -> TcM r
solveEqualities                              (TcM ([TyVar], ([TyVar], (Kind, Kind)))
 -> TcM ([TyVar], ([TyVar], (Kind, Kind))))
-> TcM ([TyVar], ([TyVar], (Kind, Kind)))
-> TcM ([TyVar], ([TyVar], (Kind, Kind)))
forall a b. (a -> b) -> a -> b
$
                  [Name]
-> TcM ([TyVar], (Kind, Kind))
-> TcM ([TyVar], ([TyVar], (Kind, Kind)))
forall a. [Name] -> TcM a -> TcM ([TyVar], a)
bindImplicitTKBndrs_Q_Skol [Name]
imp_vars          (TcM ([TyVar], (Kind, Kind))
 -> TcM ([TyVar], ([TyVar], (Kind, Kind))))
-> TcM ([TyVar], (Kind, Kind))
-> TcM ([TyVar], ([TyVar], (Kind, Kind)))
forall a b. (a -> b) -> a -> b
$
                  ContextKind
-> [LHsTyVarBndr GhcRn]
-> TcM (Kind, Kind)
-> TcM ([TyVar], (Kind, Kind))
forall a.
ContextKind -> [LHsTyVarBndr GhcRn] -> TcM a -> TcM ([TyVar], a)
bindExplicitTKBndrs_Q_Skol ContextKind
AnyKind [LHsTyVarBndr GhcRn]
exp_bndrs (TcM (Kind, Kind) -> TcM ([TyVar], (Kind, Kind)))
-> TcM (Kind, Kind) -> TcM ([TyVar], (Kind, Kind))
forall a b. (a -> b) -> a -> b
$
                  do { (lhs_ty :: Kind
lhs_ty, rhs_kind :: Kind
rhs_kind) <- TcM (Kind, Kind)
tc_lhs
                       -- Ensure that the instance is consistent with its
                       -- parent class (#16008)
                     ; AssocInstInfo -> Kind -> TcRn ()
addConsistencyConstraints AssocInstInfo
mb_clsinfo Kind
lhs_ty
                     ; Kind
rhs_ty <- LHsKind GhcRn -> Kind -> TcM Kind
tcCheckLHsType LHsKind GhcRn
hs_rhs_ty Kind
rhs_kind
                     ; (Kind, Kind) -> TcM (Kind, Kind)
forall (m :: * -> *) a. Monad m => a -> m a
return (Kind
lhs_ty, Kind
rhs_ty) }

       -- See Note [Generalising in tcFamTyPatsGuts]
       -- This code (and the stuff immediately above) is very similar
       -- to that in tcDataFamHeader.  Maybe we should abstract the
       -- common code; but for the moment I concluded that it's
       -- clearer to duplicate it.  Still, if you fix a bug here,
       -- check there too!
       ; let scoped_tvs :: [TyVar]
scoped_tvs = [TyVar]
imp_tvs [TyVar] -> [TyVar] -> [TyVar]
forall a. [a] -> [a] -> [a]
++ [TyVar]
exp_tvs
       ; CandidatesQTvs
dvs  <- [Kind] -> TcM CandidatesQTvs
candidateQTyVarsOfTypes (Kind
lhs_ty Kind -> [Kind] -> [Kind]
forall a. a -> [a] -> [a]
: [TyVar] -> [Kind]
mkTyVarTys [TyVar]
scoped_tvs)
       ; [TyVar]
qtvs <- TcTyCoVarSet
-> CandidatesQTvs -> IOEnv (Env TcGblEnv TcLclEnv) [TyVar]
quantifyTyVars TcTyCoVarSet
emptyVarSet CandidatesQTvs
dvs

       ; (ze :: ZonkEnv
ze, qtvs :: [TyVar]
qtvs) <- [TyVar] -> TcM (ZonkEnv, [TyVar])
zonkTyBndrs [TyVar]
qtvs
       ; Kind
lhs_ty     <- ZonkEnv -> Kind -> TcM Kind
zonkTcTypeToTypeX ZonkEnv
ze Kind
lhs_ty
       ; Kind
rhs_ty     <- ZonkEnv -> Kind -> TcM Kind
zonkTcTypeToTypeX ZonkEnv
ze Kind
rhs_ty

       ; let pats :: [Kind]
pats = Kind -> [Kind]
unravelFamInstPats Kind
lhs_ty
             -- Note that we do this after solveEqualities
             -- so that any strange coercions inside lhs_ty
             -- have been solved before we attempt to unravel it
       ; String -> SDoc -> TcRn ()
traceTc "tcTyFamInstEqnGuts }" (TyCon -> SDoc
forall a. Outputable a => a -> SDoc
ppr TyCon
fam_tc SDoc -> SDoc -> SDoc
<+> [TyVar] -> SDoc
pprTyVars [TyVar]
qtvs)
       ; ([TyVar], [Kind], Kind) -> TcM ([TyVar], [Kind], Kind)
forall (m :: * -> *) a. Monad m => a -> m a
return ([TyVar]
qtvs, [Kind]
pats, Kind
rhs_ty) }
  where
    tc_lhs :: TcM (Kind, Kind)
tc_lhs | [HsArg (LHsKind GhcRn) (LHsKind GhcRn)] -> Bool
forall (t :: * -> *) a. Foldable t => t a -> Bool
null [HsArg (LHsKind GhcRn) (LHsKind GhcRn)]
hs_pats  -- See Note [Apparently-nullary families]
           = do { (args :: [Kind]
args, rhs_kind :: Kind
rhs_kind) <- ([TyCoBinder], Kind) -> TcM ([Kind], Kind)
HasDebugCallStack => ([TyCoBinder], Kind) -> TcM ([Kind], Kind)
tcInstTyBinders (([TyCoBinder], Kind) -> TcM ([Kind], Kind))
-> ([TyCoBinder], Kind) -> TcM ([Kind], Kind)
forall a b. (a -> b) -> a -> b
$
                                      Int -> Kind -> ([TyCoBinder], Kind)
splitPiTysInvisibleN (TyCon -> Int
tyConArity TyCon
fam_tc)
                                                           (TyCon -> Kind
tyConKind  TyCon
fam_tc)
                ; (Kind, Kind) -> TcM (Kind, Kind)
forall (m :: * -> *) a. Monad m => a -> m a
return (TyCon -> [Kind] -> Kind
mkTyConApp TyCon
fam_tc [Kind]
args, Kind
rhs_kind) }
           | Bool
otherwise
           = TyCon
-> [HsArg (LHsKind GhcRn) (LHsKind GhcRn)] -> TcM (Kind, Kind)
tcFamTyPats TyCon
fam_tc [HsArg (LHsKind GhcRn) (LHsKind GhcRn)]
hs_pats

{- Note [Apparently-nullary families]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Consider
  type family F :: k -> *

This really means
  type family F @k :: k -> *

That is, the family has arity 1, and can match on the kind. So it's
not really a nullary family.   NB that
  type famly F2 :: forall k. k -> *
is quite different and really does have arity 0.

Returning to F we might have
  type instannce F = Maybe
which instantaite 'k' to '*' and really means
  type instannce F @* = Maybe

Conclusion: in this odd case where there are no LHS patterns, we
should instantiate any invisible foralls in F's kind, to saturate
its arity (but no more).  This is what happens in tc_lhs in
tcTyFamInstEqnGuts.

If there are any visible patterns, then the first will force
instantiation of any Inferred quantifiers for F -- remember,
Inferred quantifiers always come first.
-}


-----------------
tcFamTyPats :: TyCon
            -> HsTyPats GhcRn                -- Patterns
            -> TcM (TcType, TcKind)          -- (lhs_type, lhs_kind)
-- Used for both type and data families
tcFamTyPats :: TyCon
-> [HsArg (LHsKind GhcRn) (LHsKind GhcRn)] -> TcM (Kind, Kind)
tcFamTyPats fam_tc :: TyCon
fam_tc hs_pats :: [HsArg (LHsKind GhcRn) (LHsKind GhcRn)]
hs_pats
  = do { String -> SDoc -> TcRn ()
traceTc "tcFamTyPats {" (SDoc -> TcRn ()) -> SDoc -> TcRn ()
forall a b. (a -> b) -> a -> b
$
         [SDoc] -> SDoc
vcat [ TyCon -> SDoc
forall a. Outputable a => a -> SDoc
ppr TyCon
fam_tc SDoc -> SDoc -> SDoc
<+> SDoc
dcolon SDoc -> SDoc -> SDoc
<+> Kind -> SDoc
forall a. Outputable a => a -> SDoc
ppr Kind
fam_kind
              , String -> SDoc
text "arity:" SDoc -> SDoc -> SDoc
<+> Int -> SDoc
forall a. Outputable a => a -> SDoc
ppr Int
fam_arity
              , String -> SDoc
text "kind:" SDoc -> SDoc -> SDoc
<+> Kind -> SDoc
forall a. Outputable a => a -> SDoc
ppr Kind
fam_kind ]

       ; let fun_ty :: Kind
fun_ty = TyCon -> [Kind] -> Kind
mkTyConApp TyCon
fam_tc []

       ; (fam_app :: Kind
fam_app, res_kind :: Kind
res_kind) <- WarningFlag -> TcM (Kind, Kind) -> TcM (Kind, Kind)
forall gbl lcl a.
WarningFlag -> TcRnIf gbl lcl a -> TcRnIf gbl lcl a
unsetWOptM WarningFlag
Opt_WarnPartialTypeSignatures (TcM (Kind, Kind) -> TcM (Kind, Kind))
-> TcM (Kind, Kind) -> TcM (Kind, Kind)
forall a b. (a -> b) -> a -> b
$
                                Extension -> TcM (Kind, Kind) -> TcM (Kind, Kind)
forall gbl lcl a. Extension -> TcRnIf gbl lcl a -> TcRnIf gbl lcl a
setXOptM Extension
LangExt.PartialTypeSignatures (TcM (Kind, Kind) -> TcM (Kind, Kind))
-> TcM (Kind, Kind) -> TcM (Kind, Kind)
forall a b. (a -> b) -> a -> b
$
                                -- See Note [Wildcards in family instances] in
                                -- RnSource.hs
                                TcTyMode
-> LHsKind GhcRn
-> Kind
-> Kind
-> [HsArg (LHsKind GhcRn) (LHsKind GhcRn)]
-> TcM (Kind, Kind)
tcInferApps TcTyMode
typeLevelMode LHsKind GhcRn
lhs_fun Kind
fun_ty
                                            Kind
fam_kind [HsArg (LHsKind GhcRn) (LHsKind GhcRn)]
hs_pats

       ; String -> SDoc -> TcRn ()
traceTc "End tcFamTyPats }" (SDoc -> TcRn ()) -> SDoc -> TcRn ()
forall a b. (a -> b) -> a -> b
$
         [SDoc] -> SDoc
vcat [ TyCon -> SDoc
forall a. Outputable a => a -> SDoc
ppr TyCon
fam_tc SDoc -> SDoc -> SDoc
<+> SDoc
dcolon SDoc -> SDoc -> SDoc
<+> Kind -> SDoc
forall a. Outputable a => a -> SDoc
ppr Kind
fam_kind
              , String -> SDoc
text "res_kind:" SDoc -> SDoc -> SDoc
<+> Kind -> SDoc
forall a. Outputable a => a -> SDoc
ppr Kind
res_kind ]

       ; (Kind, Kind) -> TcM (Kind, Kind)
forall (m :: * -> *) a. Monad m => a -> m a
return (Kind
fam_app, Kind
res_kind) }
  where
    fam_name :: Name
fam_name  = TyCon -> Name
tyConName TyCon
fam_tc
    fam_arity :: Int
fam_arity = TyCon -> Int
tyConArity TyCon
fam_tc
    fam_kind :: Kind
fam_kind  = TyCon -> Kind
tyConKind TyCon
fam_tc
    lhs_fun :: LHsKind GhcRn
lhs_fun   = SrcSpanLess (LHsKind GhcRn) -> LHsKind GhcRn
forall a. HasSrcSpan a => SrcSpanLess a -> a
noLoc (XTyVar GhcRn
-> PromotionFlag -> GenLocated SrcSpan (IdP GhcRn) -> HsType GhcRn
forall pass.
XTyVar pass -> PromotionFlag -> Located (IdP pass) -> HsType pass
HsTyVar XTyVar GhcRn
NoExt
noExt PromotionFlag
NotPromoted (SrcSpanLess (Located Name) -> Located Name
forall a. HasSrcSpan a => SrcSpanLess a -> a
noLoc Name
SrcSpanLess (Located Name)
fam_name))

unravelFamInstPats :: TcType -> [TcType]
-- Decompose fam_app to get the argument patterns
--
-- We expect fam_app to look like (F t1 .. tn)
-- tcInferApps is capable of returning ((F ty1 |> co) ty2),
-- but that can't happen here because we already checked the
-- arity of F matches the number of pattern
unravelFamInstPats :: Kind -> [Kind]
unravelFamInstPats fam_app :: Kind
fam_app
  = case HasDebugCallStack => Kind -> Maybe (TyCon, [Kind])
Kind -> Maybe (TyCon, [Kind])
splitTyConApp_maybe Kind
fam_app of
      Just (_, pats :: [Kind]
pats) -> [Kind]
pats
      Nothing        -> WARN( True, bad_lhs fam_app ) []
        -- The Nothing case cannot happen for type families, because
        -- we don't call unravelFamInstPats until we've solved the
        -- equalities.  For data families I wasn't quite as convinced
        -- so I've let it as a warning rather than a panic.
  where
    bad_lhs :: Kind -> SDoc
bad_lhs fam_app :: Kind
fam_app
      = SDoc -> Int -> SDoc -> SDoc
hang (String -> SDoc
text "Ill-typed LHS of family instance")
           2 (Kind -> SDoc
debugPprType Kind
fam_app)

addConsistencyConstraints :: AssocInstInfo -> TcType -> TcM ()
-- In the corresponding positions of the class and type-family,
-- ensure the the family argument is the same as the class argument
--   E.g    class C a b c d where
--             F c x y a :: Type
-- Here the first  arg of F should be the same as the third of C
--  and the fourth arg of F should be the same as the first of C
--
-- We emit /Derived/ constraints (a bit like fundeps) to encourage
-- unification to happen, but without actually reporting errors.
-- If, despite the efforts, corresponding positions do not match,
-- checkConsistentFamInst will complain
addConsistencyConstraints :: AssocInstInfo -> Kind -> TcRn ()
addConsistencyConstraints mb_clsinfo :: AssocInstInfo
mb_clsinfo fam_app :: Kind
fam_app
  | InClsInst { ai_inst_env :: AssocInstInfo -> VarEnv Kind
ai_inst_env = VarEnv Kind
inst_env } <- AssocInstInfo
mb_clsinfo
  , Just (fam_tc :: TyCon
fam_tc, pats :: [Kind]
pats) <- HasCallStack => Kind -> Maybe (TyCon, [Kind])
Kind -> Maybe (TyCon, [Kind])
tcSplitTyConApp_maybe Kind
fam_app
  = do { let eqs :: [(Kind, Kind)]
eqs = [ (Kind
cls_ty, Kind
pat)
                   | (fam_tc_tv :: TyVar
fam_tc_tv, pat :: Kind
pat) <- TyCon -> [TyVar]
tyConTyVars TyCon
fam_tc [TyVar] -> [Kind] -> [(TyVar, Kind)]
forall a b. [a] -> [b] -> [(a, b)]
`zip` [Kind]
pats
                   , Just cls_ty :: Kind
cls_ty <- [VarEnv Kind -> TyVar -> Maybe Kind
forall a. VarEnv a -> TyVar -> Maybe a
lookupVarEnv VarEnv Kind
inst_env TyVar
fam_tc_tv] ]
       ; String -> SDoc -> TcRn ()
traceTc "addConsistencyConstraints" ([(Kind, Kind)] -> SDoc
forall a. Outputable a => a -> SDoc
ppr [(Kind, Kind)]
eqs)
       ; CtOrigin -> [(Kind, Kind)] -> TcRn ()
emitDerivedEqs CtOrigin
AssocFamPatOrigin [(Kind, Kind)]
eqs }
    -- Improve inference
    -- Any mis-match is reports by checkConsistentFamInst
  | Bool
otherwise
  = () -> TcRn ()
forall (m :: * -> *) a. Monad m => a -> m a
return ()

{- Note [Constraints in patterns]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
NB: This isn't the whole story. See comment in tcFamTyPats.

At first glance, it seems there is a complicated story to tell in tcFamTyPats
around constraint solving. After all, type family patterns can now do
GADT pattern-matching, which is jolly complicated. But, there's a key fact
which makes this all simple: everything is at top level! There cannot
be untouchable type variables. There can't be weird interaction between
case branches. There can't be global skolems.

This means that the semantics of type-level GADT matching is a little
different than term level. If we have

  data G a where
    MkGBool :: G Bool

And then

  type family F (a :: G k) :: k
  type instance F MkGBool = True

we get

  axF : F Bool (MkGBool <Bool>) ~ True

Simple! No casting on the RHS, because we can affect the kind parameter
to F.

If we ever introduce local type families, this all gets a lot more
complicated, and will end up looking awfully like term-level GADT
pattern-matching.


** The new story **

Here is really what we want:

The matcher really can't deal with covars in arbitrary spots in coercions.
But it can deal with covars that are arguments to GADT data constructors.
So we somehow want to allow covars only in precisely those spots, then use
them as givens when checking the RHS. TODO (RAE): Implement plan.


Note [Quantifying over family patterns]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
We need to quantify over two different lots of kind variables:

First, the ones that come from the kinds of the tyvar args of
tcTyVarBndrsKindGen, as usual
  data family Dist a

  -- Proxy :: forall k. k -> *
  data instance Dist (Proxy a) = DP
  -- Generates  data DistProxy = DP
  --            ax8 k (a::k) :: Dist * (Proxy k a) ~ DistProxy k a
  -- The 'k' comes from the tcTyVarBndrsKindGen (a::k)

Second, the ones that come from the kind argument of the type family
which we pick up using the (tyCoVarsOfTypes typats) in the result of
the thing_inside of tcHsTyvarBndrsGen.
  -- Any :: forall k. k
  data instance Dist Any = DA
  -- Generates  data DistAny k = DA
  --            ax7 k :: Dist k (Any k) ~ DistAny k
  -- The 'k' comes from kindGeneralizeKinds (Any k)

Note [Quantified kind variables of a family pattern]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Consider   type family KindFam (p :: k1) (q :: k1)
           data T :: Maybe k1 -> k2 -> *
           type instance KindFam (a :: Maybe k) b = T a b -> Int
The HsBSig for the family patterns will be ([k], [a])

Then in the family instance we want to
  * Bring into scope [ "k" -> k:*, "a" -> a:k ]
  * Kind-check the RHS
  * Quantify the type instance over k and k', as well as a,b, thus
       type instance [k, k', a:Maybe k, b:k']
                     KindFam (Maybe k) k' a b = T k k' a b -> Int

Notice that in the third step we quantify over all the visibly-mentioned
type variables (a,b), but also over the implicitly mentioned kind variables
(k, k').  In this case one is bound explicitly but often there will be
none. The role of the kind signature (a :: Maybe k) is to add a constraint
that 'a' must have that kind, and to bring 'k' into scope.



************************************************************************
*                                                                      *
               Data types
*                                                                      *
************************************************************************
-}

dataDeclChecks :: Name -> NewOrData
               -> LHsContext GhcRn -> [LConDecl GhcRn]
               -> TcM Bool
dataDeclChecks :: Name
-> NewOrData -> LHsContext GhcRn -> [LConDecl GhcRn] -> TcRn Bool
dataDeclChecks tc_name :: Name
tc_name new_or_data :: NewOrData
new_or_data (L _ stupid_theta :: [LHsKind GhcRn]
stupid_theta) cons :: [LConDecl GhcRn]
cons
  = do {   -- Check that we don't use GADT syntax in H98 world
         Bool
gadtSyntax_ok <- Extension -> TcRn Bool
forall gbl lcl. Extension -> TcRnIf gbl lcl Bool
xoptM Extension
LangExt.GADTSyntax
       ; let gadt_syntax :: Bool
gadt_syntax = [LConDecl GhcRn] -> Bool
forall a. [LConDecl a] -> Bool
consUseGadtSyntax [LConDecl GhcRn]
cons
       ; Bool -> SDoc -> TcRn ()
checkTc (Bool
gadtSyntax_ok Bool -> Bool -> Bool
|| Bool -> Bool
not Bool
gadt_syntax) (Name -> SDoc
badGadtDecl Name
tc_name)

           -- Check that the stupid theta is empty for a GADT-style declaration
       ; Bool -> SDoc -> TcRn ()
checkTc ([LHsKind GhcRn] -> Bool
forall (t :: * -> *) a. Foldable t => t a -> Bool
null [LHsKind GhcRn]
stupid_theta Bool -> Bool -> Bool
|| Bool -> Bool
not Bool
gadt_syntax) (Name -> SDoc
badStupidTheta Name
tc_name)

         -- Check that a newtype has exactly one constructor
         -- Do this before checking for empty data decls, so that
         -- we don't suggest -XEmptyDataDecls for newtypes
       ; Bool -> SDoc -> TcRn ()
checkTc (NewOrData
new_or_data NewOrData -> NewOrData -> Bool
forall a. Eq a => a -> a -> Bool
== NewOrData
DataType Bool -> Bool -> Bool
|| [LConDecl GhcRn] -> Bool
forall a. [a] -> Bool
isSingleton [LConDecl GhcRn]
cons)
                (Name -> Int -> SDoc
newtypeConError Name
tc_name ([LConDecl GhcRn] -> Int
forall (t :: * -> *) a. Foldable t => t a -> Int
length [LConDecl GhcRn]
cons))

         -- Check that there's at least one condecl,
         -- or else we're reading an hs-boot file, or -XEmptyDataDecls
       ; Bool
empty_data_decls <- Extension -> TcRn Bool
forall gbl lcl. Extension -> TcRnIf gbl lcl Bool
xoptM Extension
LangExt.EmptyDataDecls
       ; Bool
is_boot <- TcRn Bool
tcIsHsBootOrSig  -- Are we compiling an hs-boot file?
       ; Bool -> SDoc -> TcRn ()
checkTc (Bool -> Bool
not ([LConDecl GhcRn] -> Bool
forall (t :: * -> *) a. Foldable t => t a -> Bool
null [LConDecl GhcRn]
cons) Bool -> Bool -> Bool
|| Bool
empty_data_decls Bool -> Bool -> Bool
|| Bool
is_boot)
                 (Name -> SDoc
emptyConDeclsErr Name
tc_name)
       ; Bool -> TcRn Bool
forall (m :: * -> *) a. Monad m => a -> m a
return Bool
gadt_syntax }


-----------------------------------
consUseGadtSyntax :: [LConDecl a] -> Bool
consUseGadtSyntax :: [LConDecl a] -> Bool
consUseGadtSyntax ((LConDecl a -> Located (SrcSpanLess (LConDecl a))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L _ (ConDeclGADT {})) : _) = Bool
True
consUseGadtSyntax _                                = Bool
False
                 -- All constructors have same shape

-----------------------------------
tcConDecls :: KnotTied TyCon -> [KnotTied TyConBinder] -> KnotTied Type
           -> [LConDecl GhcRn] -> TcM [DataCon]
  -- Why both the tycon tyvars and binders? Because the tyvars
  -- have all the names and the binders have the visibilities.
tcConDecls :: TyCon -> [TyConBinder] -> Kind -> [LConDecl GhcRn] -> TcM [DataCon]
tcConDecls rep_tycon :: TyCon
rep_tycon tmpl_bndrs :: [TyConBinder]
tmpl_bndrs res_tmpl :: Kind
res_tmpl
  = (LConDecl GhcRn -> TcM [DataCon])
-> [LConDecl GhcRn] -> TcM [DataCon]
forall (m :: * -> *) a b. Monad m => (a -> m [b]) -> [a] -> m [b]
concatMapM ((LConDecl GhcRn -> TcM [DataCon])
 -> [LConDecl GhcRn] -> TcM [DataCon])
-> (LConDecl GhcRn -> TcM [DataCon])
-> [LConDecl GhcRn]
-> TcM [DataCon]
forall a b. (a -> b) -> a -> b
$ (SrcSpanLess (LConDecl GhcRn) -> TcM [DataCon])
-> LConDecl GhcRn -> TcM [DataCon]
forall a b. HasSrcSpan a => (SrcSpanLess a -> TcM b) -> a -> TcM b
addLocM ((SrcSpanLess (LConDecl GhcRn) -> TcM [DataCon])
 -> LConDecl GhcRn -> TcM [DataCon])
-> (SrcSpanLess (LConDecl GhcRn) -> TcM [DataCon])
-> LConDecl GhcRn
-> TcM [DataCon]
forall a b. (a -> b) -> a -> b
$
    TyCon
-> NameEnv Int
-> [TyConBinder]
-> Kind
-> ConDecl GhcRn
-> TcM [DataCon]
tcConDecl TyCon
rep_tycon (TyCon -> NameEnv Int
mkTyConTagMap TyCon
rep_tycon) [TyConBinder]
tmpl_bndrs Kind
res_tmpl
    -- It's important that we pay for tag allocation here, once per TyCon,
    -- See Note [Constructor tag allocation], fixes #14657

tcConDecl :: KnotTied TyCon          -- Representation tycon. Knot-tied!
          -> NameEnv ConTag
          -> [KnotTied TyConBinder] -> KnotTied Type
                 -- Return type template (with its template tyvars)
                 --    (tvs, T tys), where T is the family TyCon
          -> ConDecl GhcRn
          -> TcM [DataCon]

tcConDecl :: TyCon
-> NameEnv Int
-> [TyConBinder]
-> Kind
-> ConDecl GhcRn
-> TcM [DataCon]
tcConDecl rep_tycon :: TyCon
rep_tycon tag_map :: NameEnv Int
tag_map tmpl_bndrs :: [TyConBinder]
tmpl_bndrs res_tmpl :: Kind
res_tmpl
          (ConDeclH98 { con_name :: forall pass. ConDecl pass -> Located (IdP pass)
con_name = GenLocated SrcSpan (IdP GhcRn)
name
                      , con_ex_tvs :: forall pass. ConDecl pass -> [LHsTyVarBndr pass]
con_ex_tvs = [LHsTyVarBndr GhcRn]
explicit_tkv_nms
                      , con_mb_cxt :: forall pass. ConDecl pass -> Maybe (LHsContext pass)
con_mb_cxt = Maybe (LHsContext GhcRn)
hs_ctxt
                      , con_args :: forall pass. ConDecl pass -> HsConDeclDetails pass
con_args = HsConDeclDetails GhcRn
hs_args })
  = SDoc -> TcM [DataCon] -> TcM [DataCon]
forall a. SDoc -> TcM a -> TcM a
addErrCtxt ([Located Name] -> SDoc
dataConCtxtName [Located Name
GenLocated SrcSpan (IdP GhcRn)
name]) (TcM [DataCon] -> TcM [DataCon]) -> TcM [DataCon] -> TcM [DataCon]
forall a b. (a -> b) -> a -> b
$
    do { -- NB: the tyvars from the declaration header are in scope

         -- Get hold of the existential type variables
         -- e.g. data T a = forall k (b::k) f. MkT a (f b)
         -- Here tmpl_bndrs = {a}
         --      hs_qvars = HsQTvs { hsq_implicit = {k}
         --                        , hsq_explicit = {f,b} }

       ; String -> SDoc -> TcRn ()
traceTc "tcConDecl 1" ([SDoc] -> SDoc
vcat [ Located Name -> SDoc
forall a. Outputable a => a -> SDoc
ppr Located Name
GenLocated SrcSpan (IdP GhcRn)
name, [LHsTyVarBndr GhcRn] -> SDoc
forall a. Outputable a => a -> SDoc
ppr [LHsTyVarBndr GhcRn]
explicit_tkv_nms ])

       ; (exp_tvs :: [TyVar]
exp_tvs, (ctxt :: [Kind]
ctxt, arg_tys :: [Kind]
arg_tys, field_lbls :: [FieldLabel]
field_lbls, stricts :: [HsSrcBang]
stricts))
           <- TcM ([TyVar], ([Kind], [Kind], [FieldLabel], [HsSrcBang]))
-> TcM ([TyVar], ([Kind], [Kind], [FieldLabel], [HsSrcBang]))
forall r. TcM r -> TcM r
pushTcLevelM_                             (TcM ([TyVar], ([Kind], [Kind], [FieldLabel], [HsSrcBang]))
 -> TcM ([TyVar], ([Kind], [Kind], [FieldLabel], [HsSrcBang])))
-> TcM ([TyVar], ([Kind], [Kind], [FieldLabel], [HsSrcBang]))
-> TcM ([TyVar], ([Kind], [Kind], [FieldLabel], [HsSrcBang]))
forall a b. (a -> b) -> a -> b
$
              TcM ([TyVar], ([Kind], [Kind], [FieldLabel], [HsSrcBang]))
-> TcM ([TyVar], ([Kind], [Kind], [FieldLabel], [HsSrcBang]))
forall r. TcM r -> TcM r
solveEqualities                           (TcM ([TyVar], ([Kind], [Kind], [FieldLabel], [HsSrcBang]))
 -> TcM ([TyVar], ([Kind], [Kind], [FieldLabel], [HsSrcBang])))
-> TcM ([TyVar], ([Kind], [Kind], [FieldLabel], [HsSrcBang]))
-> TcM ([TyVar], ([Kind], [Kind], [FieldLabel], [HsSrcBang]))
forall a b. (a -> b) -> a -> b
$
              [LHsTyVarBndr GhcRn]
-> TcM ([Kind], [Kind], [FieldLabel], [HsSrcBang])
-> TcM ([TyVar], ([Kind], [Kind], [FieldLabel], [HsSrcBang]))
forall a. [LHsTyVarBndr GhcRn] -> TcM a -> TcM ([TyVar], a)
bindExplicitTKBndrs_Skol [LHsTyVarBndr GhcRn]
explicit_tkv_nms (TcM ([Kind], [Kind], [FieldLabel], [HsSrcBang])
 -> TcM ([TyVar], ([Kind], [Kind], [FieldLabel], [HsSrcBang])))
-> TcM ([Kind], [Kind], [FieldLabel], [HsSrcBang])
-> TcM ([TyVar], ([Kind], [Kind], [FieldLabel], [HsSrcBang]))
forall a b. (a -> b) -> a -> b
$
              do { [Kind]
ctxt <- Maybe (LHsContext GhcRn) -> TcM [Kind]
tcHsMbContext Maybe (LHsContext GhcRn)
hs_ctxt
                 ; [(Kind, HsSrcBang)]
btys <- HsConDeclDetails GhcRn -> TcM [(Kind, HsSrcBang)]
tcConArgs HsConDeclDetails GhcRn
hs_args
                 ; [FieldLabel]
field_lbls <- Name -> RnM [FieldLabel]
lookupConstructorFields (Located Name -> SrcSpanLess (Located Name)
forall a. HasSrcSpan a => a -> SrcSpanLess a
unLoc Located Name
GenLocated SrcSpan (IdP GhcRn)
name)
                 ; let (arg_tys :: [Kind]
arg_tys, stricts :: [HsSrcBang]
stricts) = [(Kind, HsSrcBang)] -> ([Kind], [HsSrcBang])
forall a b. [(a, b)] -> ([a], [b])
unzip [(Kind, HsSrcBang)]
btys
                 ; ([Kind], [Kind], [FieldLabel], [HsSrcBang])
-> TcM ([Kind], [Kind], [FieldLabel], [HsSrcBang])
forall (m :: * -> *) a. Monad m => a -> m a
return ([Kind]
ctxt, [Kind]
arg_tys, [FieldLabel]
field_lbls, [HsSrcBang]
stricts)
                 }

         -- exp_tvs have explicit, user-written binding sites
         -- the kvs below are those kind variables entirely unmentioned by the user
         --   and discovered only by generalization

       ; [TyVar]
kvs <- Kind -> IOEnv (Env TcGblEnv TcLclEnv) [TyVar]
kindGeneralize ([TyVar] -> Kind -> Kind
mkSpecForAllTys ([TyConBinder] -> [TyVar]
forall tv argf. [VarBndr tv argf] -> [tv]
binderVars [TyConBinder]
tmpl_bndrs) (Kind -> Kind) -> Kind -> Kind
forall a b. (a -> b) -> a -> b
$
                                [TyVar] -> Kind -> Kind
mkSpecForAllTys [TyVar]
exp_tvs (Kind -> Kind) -> Kind -> Kind
forall a b. (a -> b) -> a -> b
$
                                [Kind] -> Kind -> Kind
mkFunTys [Kind]
ctxt (Kind -> Kind) -> Kind -> Kind
forall a b. (a -> b) -> a -> b
$
                                [Kind] -> Kind -> Kind
mkFunTys [Kind]
arg_tys (Kind -> Kind) -> Kind -> Kind
forall a b. (a -> b) -> a -> b
$
                                Kind
unitTy)
                 -- That type is a lie, of course. (It shouldn't end in ()!)
                 -- And we could construct a proper result type from the info
                 -- at hand. But the result would mention only the tmpl_tvs,
                 -- and so it just creates more work to do it right. Really,
                 -- we're only doing this to find the right kind variables to
                 -- quantify over, and this type is fine for that purpose.

             -- Zonk to Types
       ; (ze :: ZonkEnv
ze, qkvs :: [TyVar]
qkvs)      <- [TyVar] -> TcM (ZonkEnv, [TyVar])
zonkTyBndrs [TyVar]
kvs
       ; (ze :: ZonkEnv
ze, user_qtvs :: [TyVar]
user_qtvs) <- ZonkEnv -> [TyVar] -> TcM (ZonkEnv, [TyVar])
zonkTyBndrsX ZonkEnv
ze [TyVar]
exp_tvs
       ; [Kind]
arg_tys         <- ZonkEnv -> [Kind] -> TcM [Kind]
zonkTcTypesToTypesX ZonkEnv
ze [Kind]
arg_tys
       ; [Kind]
ctxt            <- ZonkEnv -> [Kind] -> TcM [Kind]
zonkTcTypesToTypesX ZonkEnv
ze [Kind]
ctxt

       ; FamInstEnvs
fam_envs <- TcM FamInstEnvs
tcGetFamInstEnvs

       -- Can't print univ_tvs, arg_tys etc, because we are inside the knot here
       ; String -> SDoc -> TcRn ()
traceTc "tcConDecl 2" (Located Name -> SDoc
forall a. Outputable a => a -> SDoc
ppr Located Name
GenLocated SrcSpan (IdP GhcRn)
name SDoc -> SDoc -> SDoc
$$ [FieldLabel] -> SDoc
forall a. Outputable a => a -> SDoc
ppr [FieldLabel]
field_lbls)
       ; let
           univ_tvbs :: [TyVarBinder]
univ_tvbs = [TyConBinder] -> [TyVarBinder]
tyConTyVarBinders [TyConBinder]
tmpl_bndrs
           univ_tvs :: [TyVar]
univ_tvs  = [TyVarBinder] -> [TyVar]
forall tv argf. [VarBndr tv argf] -> [tv]
binderVars [TyVarBinder]
univ_tvbs
           ex_tvbs :: [TyVarBinder]
ex_tvbs   = ArgFlag -> [TyVar] -> [TyVarBinder]
mkTyVarBinders ArgFlag
Inferred [TyVar]
qkvs [TyVarBinder] -> [TyVarBinder] -> [TyVarBinder]
forall a. [a] -> [a] -> [a]
++
                       ArgFlag -> [TyVar] -> [TyVarBinder]
mkTyVarBinders ArgFlag
Specified [TyVar]
user_qtvs
           ex_tvs :: [TyVar]
ex_tvs    = [TyVar]
qkvs [TyVar] -> [TyVar] -> [TyVar]
forall a. [a] -> [a] -> [a]
++ [TyVar]
user_qtvs
           -- For H98 datatypes, the user-written tyvar binders are precisely
           -- the universals followed by the existentials.
           -- See Note [DataCon user type variable binders] in DataCon.
           user_tvbs :: [TyVarBinder]
user_tvbs = [TyVarBinder]
univ_tvbs [TyVarBinder] -> [TyVarBinder] -> [TyVarBinder]
forall a. [a] -> [a] -> [a]
++ [TyVarBinder]
ex_tvbs
           buildOneDataCon :: Located Name -> IOEnv (Env TcGblEnv TcLclEnv) DataCon
buildOneDataCon (Located Name -> Located (SrcSpanLess (Located Name))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L _ name :: SrcSpanLess (Located Name)
name) = do
             { Bool
is_infix <- Name -> HsConDeclDetails GhcRn -> TcRn Bool
tcConIsInfixH98 Name
SrcSpanLess (Located Name)
name HsConDeclDetails GhcRn
hs_args
             ; Name
rep_nm   <- Name -> TcRnIf TcGblEnv TcLclEnv Name
forall gbl lcl. Name -> TcRnIf gbl lcl Name
newTyConRepName Name
SrcSpanLess (Located Name)
name

             ; FamInstEnvs
-> Name
-> Bool
-> Name
-> [HsSrcBang]
-> Maybe [HsImplBang]
-> [FieldLabel]
-> [TyVar]
-> [TyVar]
-> [TyVarBinder]
-> [EqSpec]
-> [Kind]
-> [Kind]
-> Kind
-> TyCon
-> NameEnv Int
-> IOEnv (Env TcGblEnv TcLclEnv) DataCon
forall m n.
FamInstEnvs
-> Name
-> Bool
-> Name
-> [HsSrcBang]
-> Maybe [HsImplBang]
-> [FieldLabel]
-> [TyVar]
-> [TyVar]
-> [TyVarBinder]
-> [EqSpec]
-> [Kind]
-> [Kind]
-> Kind
-> TyCon
-> NameEnv Int
-> TcRnIf m n DataCon
buildDataCon FamInstEnvs
fam_envs Name
SrcSpanLess (Located Name)
name Bool
is_infix Name
rep_nm
                            [HsSrcBang]
stricts Maybe [HsImplBang]
forall a. Maybe a
Nothing [FieldLabel]
field_lbls
                            [TyVar]
univ_tvs [TyVar]
ex_tvs [TyVarBinder]
user_tvbs
                            [{- no eq_preds -}] [Kind]
ctxt [Kind]
arg_tys
                            Kind
res_tmpl TyCon
rep_tycon NameEnv Int
tag_map
                  -- NB:  we put data_tc, the type constructor gotten from the
                  --      constructor type signature into the data constructor;
                  --      that way checkValidDataCon can complain if it's wrong.
             }
       ; String -> SDoc -> TcRn ()
traceTc "tcConDecl 2" (Located Name -> SDoc
forall a. Outputable a => a -> SDoc
ppr Located Name
GenLocated SrcSpan (IdP GhcRn)
name)
       ; (Located Name -> IOEnv (Env TcGblEnv TcLclEnv) DataCon)
-> [Located Name] -> TcM [DataCon]
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
mapM Located Name -> IOEnv (Env TcGblEnv TcLclEnv) DataCon
buildOneDataCon [Located Name
GenLocated SrcSpan (IdP GhcRn)
name]
       }

tcConDecl rep_tycon :: TyCon
rep_tycon tag_map :: NameEnv Int
tag_map tmpl_bndrs :: [TyConBinder]
tmpl_bndrs res_tmpl :: Kind
res_tmpl
          (ConDeclGADT { con_names :: forall pass. ConDecl pass -> [Located (IdP pass)]
con_names = [GenLocated SrcSpan (IdP GhcRn)]
names
                       , con_qvars :: forall pass. ConDecl pass -> LHsQTyVars pass
con_qvars = LHsQTyVars GhcRn
qtvs
                       , con_mb_cxt :: forall pass. ConDecl pass -> Maybe (LHsContext pass)
con_mb_cxt = Maybe (LHsContext GhcRn)
cxt, con_args :: forall pass. ConDecl pass -> HsConDeclDetails pass
con_args = HsConDeclDetails GhcRn
hs_args
                       , con_res_ty :: forall pass. ConDecl pass -> LHsType pass
con_res_ty = LHsKind GhcRn
hs_res_ty })
  | HsQTvs { hsq_ext :: forall pass. LHsQTyVars pass -> XHsQTvs pass
hsq_ext = HsQTvsRn { hsq_implicit = implicit_tkv_nms }
           , hsq_explicit :: forall pass. LHsQTyVars pass -> [LHsTyVarBndr pass]
hsq_explicit = [LHsTyVarBndr GhcRn]
explicit_tkv_nms } <- LHsQTyVars GhcRn
qtvs
  = SDoc -> TcM [DataCon] -> TcM [DataCon]
forall a. SDoc -> TcM a -> TcM a
addErrCtxt ([Located Name] -> SDoc
dataConCtxtName [Located Name]
[GenLocated SrcSpan (IdP GhcRn)]
names) (TcM [DataCon] -> TcM [DataCon]) -> TcM [DataCon] -> TcM [DataCon]
forall a b. (a -> b) -> a -> b
$
    do { String -> SDoc -> TcRn ()
traceTc "tcConDecl 1 gadt" ([Located Name] -> SDoc
forall a. Outputable a => a -> SDoc
ppr [Located Name]
[GenLocated SrcSpan (IdP GhcRn)]
names)
       ; let ((Located Name -> Located (SrcSpanLess (Located Name))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L _ name :: SrcSpanLess (Located Name)
name) : _) = [Located Name]
[GenLocated SrcSpan (IdP GhcRn)]
names

       ; (imp_tvs :: [TyVar]
imp_tvs, (exp_tvs :: [TyVar]
exp_tvs, (ctxt :: [Kind]
ctxt, arg_tys :: [Kind]
arg_tys, res_ty :: Kind
res_ty, field_lbls :: [FieldLabel]
field_lbls, stricts :: [HsSrcBang]
stricts)))
           <- TcM
  ([TyVar],
   ([TyVar], ([Kind], [Kind], Kind, [FieldLabel], [HsSrcBang])))
-> TcM
     ([TyVar],
      ([TyVar], ([Kind], [Kind], Kind, [FieldLabel], [HsSrcBang])))
forall r. TcM r -> TcM r
pushTcLevelM_    (TcM
   ([TyVar],
    ([TyVar], ([Kind], [Kind], Kind, [FieldLabel], [HsSrcBang])))
 -> TcM
      ([TyVar],
       ([TyVar], ([Kind], [Kind], Kind, [FieldLabel], [HsSrcBang]))))
-> TcM
     ([TyVar],
      ([TyVar], ([Kind], [Kind], Kind, [FieldLabel], [HsSrcBang])))
-> TcM
     ([TyVar],
      ([TyVar], ([Kind], [Kind], Kind, [FieldLabel], [HsSrcBang])))
forall a b. (a -> b) -> a -> b
$  -- We are going to generalise
              TcM
  ([TyVar],
   ([TyVar], ([Kind], [Kind], Kind, [FieldLabel], [HsSrcBang])))
-> TcM
     ([TyVar],
      ([TyVar], ([Kind], [Kind], Kind, [FieldLabel], [HsSrcBang])))
forall r. TcM r -> TcM r
solveEqualities  (TcM
   ([TyVar],
    ([TyVar], ([Kind], [Kind], Kind, [FieldLabel], [HsSrcBang])))
 -> TcM
      ([TyVar],
       ([TyVar], ([Kind], [Kind], Kind, [FieldLabel], [HsSrcBang]))))
-> TcM
     ([TyVar],
      ([TyVar], ([Kind], [Kind], Kind, [FieldLabel], [HsSrcBang])))
-> TcM
     ([TyVar],
      ([TyVar], ([Kind], [Kind], Kind, [FieldLabel], [HsSrcBang])))
forall a b. (a -> b) -> a -> b
$  -- We won't get another crack, and we don't
                                  -- want an error cascade
              [Name]
-> TcM ([TyVar], ([Kind], [Kind], Kind, [FieldLabel], [HsSrcBang]))
-> TcM
     ([TyVar],
      ([TyVar], ([Kind], [Kind], Kind, [FieldLabel], [HsSrcBang])))
forall a. [Name] -> TcM a -> TcM ([TyVar], a)
bindImplicitTKBndrs_Skol [Name]
implicit_tkv_nms (TcM ([TyVar], ([Kind], [Kind], Kind, [FieldLabel], [HsSrcBang]))
 -> TcM
      ([TyVar],
       ([TyVar], ([Kind], [Kind], Kind, [FieldLabel], [HsSrcBang]))))
-> TcM ([TyVar], ([Kind], [Kind], Kind, [FieldLabel], [HsSrcBang]))
-> TcM
     ([TyVar],
      ([TyVar], ([Kind], [Kind], Kind, [FieldLabel], [HsSrcBang])))
forall a b. (a -> b) -> a -> b
$
              [LHsTyVarBndr GhcRn]
-> TcM ([Kind], [Kind], Kind, [FieldLabel], [HsSrcBang])
-> TcM ([TyVar], ([Kind], [Kind], Kind, [FieldLabel], [HsSrcBang]))
forall a. [LHsTyVarBndr GhcRn] -> TcM a -> TcM ([TyVar], a)
bindExplicitTKBndrs_Skol [LHsTyVarBndr GhcRn]
explicit_tkv_nms (TcM ([Kind], [Kind], Kind, [FieldLabel], [HsSrcBang])
 -> TcM
      ([TyVar], ([Kind], [Kind], Kind, [FieldLabel], [HsSrcBang])))
-> TcM ([Kind], [Kind], Kind, [FieldLabel], [HsSrcBang])
-> TcM ([TyVar], ([Kind], [Kind], Kind, [FieldLabel], [HsSrcBang]))
forall a b. (a -> b) -> a -> b
$
              do { [Kind]
ctxt <- Maybe (LHsContext GhcRn) -> TcM [Kind]
tcHsMbContext Maybe (LHsContext GhcRn)
cxt
                 ; [(Kind, HsSrcBang)]
btys <- HsConDeclDetails GhcRn -> TcM [(Kind, HsSrcBang)]
tcConArgs HsConDeclDetails GhcRn
hs_args
                 ; Kind
res_ty <- LHsKind GhcRn -> TcM Kind
tcHsLiftedType LHsKind GhcRn
hs_res_ty
                 ; [FieldLabel]
field_lbls <- Name -> RnM [FieldLabel]
lookupConstructorFields Name
SrcSpanLess (Located Name)
name
                 ; let (arg_tys :: [Kind]
arg_tys, stricts :: [HsSrcBang]
stricts) = [(Kind, HsSrcBang)] -> ([Kind], [HsSrcBang])
forall a b. [(a, b)] -> ([a], [b])
unzip [(Kind, HsSrcBang)]
btys
                 ; ([Kind], [Kind], Kind, [FieldLabel], [HsSrcBang])
-> TcM ([Kind], [Kind], Kind, [FieldLabel], [HsSrcBang])
forall (m :: * -> *) a. Monad m => a -> m a
return ([Kind]
ctxt, [Kind]
arg_tys, Kind
res_ty, [FieldLabel]
field_lbls, [HsSrcBang]
stricts)
                 }
       ; [TyVar]
imp_tvs <- [TyVar] -> IOEnv (Env TcGblEnv TcLclEnv) [TyVar]
zonkAndScopedSort [TyVar]
imp_tvs
       ; let user_tvs :: [TyVar]
user_tvs = [TyVar]
imp_tvs [TyVar] -> [TyVar] -> [TyVar]
forall a. [a] -> [a] -> [a]
++ [TyVar]
exp_tvs

       ; [TyVar]
tkvs <- Kind -> IOEnv (Env TcGblEnv TcLclEnv) [TyVar]
kindGeneralize ([TyVar] -> Kind -> Kind
mkSpecForAllTys [TyVar]
user_tvs (Kind -> Kind) -> Kind -> Kind
forall a b. (a -> b) -> a -> b
$
                                 [Kind] -> Kind -> Kind
mkFunTys [Kind]
ctxt (Kind -> Kind) -> Kind -> Kind
forall a b. (a -> b) -> a -> b
$
                                 [Kind] -> Kind -> Kind
mkFunTys [Kind]
arg_tys (Kind -> Kind) -> Kind -> Kind
forall a b. (a -> b) -> a -> b
$
                                 Kind
res_ty)

             -- Zonk to Types
       ; (ze :: ZonkEnv
ze, tkvs :: [TyVar]
tkvs)     <- [TyVar] -> TcM (ZonkEnv, [TyVar])
zonkTyBndrs [TyVar]
tkvs
       ; (ze :: ZonkEnv
ze, user_tvs :: [TyVar]
user_tvs) <- ZonkEnv -> [TyVar] -> TcM (ZonkEnv, [TyVar])
zonkTyBndrsX ZonkEnv
ze [TyVar]
user_tvs
       ; [Kind]
arg_tys <- ZonkEnv -> [Kind] -> TcM [Kind]
zonkTcTypesToTypesX ZonkEnv
ze [Kind]
arg_tys
       ; [Kind]
ctxt    <- ZonkEnv -> [Kind] -> TcM [Kind]
zonkTcTypesToTypesX ZonkEnv
ze [Kind]
ctxt
       ; Kind
res_ty  <- ZonkEnv -> Kind -> TcM Kind
zonkTcTypeToTypeX   ZonkEnv
ze Kind
res_ty

       ; let (univ_tvs :: [TyVar]
univ_tvs, ex_tvs :: [TyVar]
ex_tvs, tkvs' :: [TyVar]
tkvs', user_tvs' :: [TyVar]
user_tvs', eq_preds :: [EqSpec]
eq_preds, arg_subst :: TCvSubst
arg_subst)
               = [TyConBinder]
-> Kind
-> [TyVar]
-> [TyVar]
-> Kind
-> ([TyVar], [TyVar], [TyVar], [TyVar], [EqSpec], TCvSubst)
rejigConRes [TyConBinder]
tmpl_bndrs Kind
res_tmpl [TyVar]
tkvs [TyVar]
user_tvs Kind
res_ty
             -- NB: this is a /lazy/ binding, so we pass six thunks to
             --     buildDataCon without yet forcing the guards in rejigConRes
             -- See Note [Checking GADT return types]

             -- Compute the user-written tyvar binders. These have the same
             -- tyvars as univ_tvs/ex_tvs, but perhaps in a different order.
             -- See Note [DataCon user type variable binders] in DataCon.
             tkv_bndrs :: [TyVarBinder]
tkv_bndrs      = ArgFlag -> [TyVar] -> [TyVarBinder]
mkTyVarBinders ArgFlag
Inferred  [TyVar]
tkvs'
             user_tv_bndrs :: [TyVarBinder]
user_tv_bndrs  = ArgFlag -> [TyVar] -> [TyVarBinder]
mkTyVarBinders ArgFlag
Specified [TyVar]
user_tvs'
             all_user_bndrs :: [TyVarBinder]
all_user_bndrs = [TyVarBinder]
tkv_bndrs [TyVarBinder] -> [TyVarBinder] -> [TyVarBinder]
forall a. [a] -> [a] -> [a]
++ [TyVarBinder]
user_tv_bndrs

             ctxt' :: [Kind]
ctxt'      = HasCallStack => TCvSubst -> [Kind] -> [Kind]
TCvSubst -> [Kind] -> [Kind]
substTys TCvSubst
arg_subst [Kind]
ctxt
             arg_tys' :: [Kind]
arg_tys'   = HasCallStack => TCvSubst -> [Kind] -> [Kind]
TCvSubst -> [Kind] -> [Kind]
substTys TCvSubst
arg_subst [Kind]
arg_tys
             res_ty' :: Kind
res_ty'    = HasCallStack => TCvSubst -> Kind -> Kind
TCvSubst -> Kind -> Kind
substTy  TCvSubst
arg_subst Kind
res_ty


       ; FamInstEnvs
fam_envs <- TcM FamInstEnvs
tcGetFamInstEnvs

       -- Can't print univ_tvs, arg_tys etc, because we are inside the knot here
       ; String -> SDoc -> TcRn ()
traceTc "tcConDecl 2" ([Located Name] -> SDoc
forall a. Outputable a => a -> SDoc
ppr [Located Name]
[GenLocated SrcSpan (IdP GhcRn)]
names SDoc -> SDoc -> SDoc
$$ [FieldLabel] -> SDoc
forall a. Outputable a => a -> SDoc
ppr [FieldLabel]
field_lbls)
       ; let
           buildOneDataCon :: Located Name -> IOEnv (Env TcGblEnv TcLclEnv) DataCon
buildOneDataCon (Located Name -> Located (SrcSpanLess (Located Name))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L _ name :: SrcSpanLess (Located Name)
name) = do
             { Bool
is_infix <- Name -> HsConDeclDetails GhcRn -> TcRn Bool
tcConIsInfixGADT Name
SrcSpanLess (Located Name)
name HsConDeclDetails GhcRn
hs_args
             ; Name
rep_nm   <- Name -> TcRnIf TcGblEnv TcLclEnv Name
forall gbl lcl. Name -> TcRnIf gbl lcl Name
newTyConRepName Name
SrcSpanLess (Located Name)
name

             ; FamInstEnvs
-> Name
-> Bool
-> Name
-> [HsSrcBang]
-> Maybe [HsImplBang]
-> [FieldLabel]
-> [TyVar]
-> [TyVar]
-> [TyVarBinder]
-> [EqSpec]
-> [Kind]
-> [Kind]
-> Kind
-> TyCon
-> NameEnv Int
-> IOEnv (Env TcGblEnv TcLclEnv) DataCon
forall m n.
FamInstEnvs
-> Name
-> Bool
-> Name
-> [HsSrcBang]
-> Maybe [HsImplBang]
-> [FieldLabel]
-> [TyVar]
-> [TyVar]
-> [TyVarBinder]
-> [EqSpec]
-> [Kind]
-> [Kind]
-> Kind
-> TyCon
-> NameEnv Int
-> TcRnIf m n DataCon
buildDataCon FamInstEnvs
fam_envs Name
SrcSpanLess (Located Name)
name Bool
is_infix
                            Name
rep_nm
                            [HsSrcBang]
stricts Maybe [HsImplBang]
forall a. Maybe a
Nothing [FieldLabel]
field_lbls
                            [TyVar]
univ_tvs [TyVar]
ex_tvs [TyVarBinder]
all_user_bndrs [EqSpec]
eq_preds
                            [Kind]
ctxt' [Kind]
arg_tys' Kind
res_ty' TyCon
rep_tycon NameEnv Int
tag_map
                  -- NB:  we put data_tc, the type constructor gotten from the
                  --      constructor type signature into the data constructor;
                  --      that way checkValidDataCon can complain if it's wrong.
             }
       ; String -> SDoc -> TcRn ()
traceTc "tcConDecl 2" ([Located Name] -> SDoc
forall a. Outputable a => a -> SDoc
ppr [Located Name]
[GenLocated SrcSpan (IdP GhcRn)]
names)
       ; (Located Name -> IOEnv (Env TcGblEnv TcLclEnv) DataCon)
-> [Located Name] -> TcM [DataCon]
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
mapM Located Name -> IOEnv (Env TcGblEnv TcLclEnv) DataCon
buildOneDataCon [Located Name]
[GenLocated SrcSpan (IdP GhcRn)]
names
       }
tcConDecl _ _ _ _ (ConDeclGADT _ _ _ (XLHsQTyVars _) _ _ _ _)
  = String -> TcM [DataCon]
forall a. String -> a
panic "tcConDecl"
tcConDecl _ _ _ _ (XConDecl _) = String -> TcM [DataCon]
forall a. String -> a
panic "tcConDecl"

tcConIsInfixH98 :: Name
             -> HsConDetails (LHsType GhcRn) (Located [LConDeclField GhcRn])
             -> TcM Bool
tcConIsInfixH98 :: Name -> HsConDeclDetails GhcRn -> TcRn Bool
tcConIsInfixH98 _   details :: HsConDeclDetails GhcRn
details
  = case HsConDeclDetails GhcRn
details of
           InfixCon {}  -> Bool -> TcRn Bool
forall (m :: * -> *) a. Monad m => a -> m a
return Bool
True
           _            -> Bool -> TcRn Bool
forall (m :: * -> *) a. Monad m => a -> m a
return Bool
False

tcConIsInfixGADT :: Name
             -> HsConDetails (LHsType GhcRn) (Located [LConDeclField GhcRn])
             -> TcM Bool
tcConIsInfixGADT :: Name -> HsConDeclDetails GhcRn -> TcRn Bool
tcConIsInfixGADT con :: Name
con details :: HsConDeclDetails GhcRn
details
  = case HsConDeclDetails GhcRn
details of
           InfixCon {}  -> Bool -> TcRn Bool
forall (m :: * -> *) a. Monad m => a -> m a
return Bool
True
           RecCon {}    -> Bool -> TcRn Bool
forall (m :: * -> *) a. Monad m => a -> m a
return Bool
False
           PrefixCon arg_tys :: [LHsKind GhcRn]
arg_tys           -- See Note [Infix GADT constructors]
               | OccName -> Bool
isSymOcc (Name -> OccName
forall a. NamedThing a => a -> OccName
getOccName Name
con)
               , [_ty1 :: LHsKind GhcRn
_ty1,_ty2 :: LHsKind GhcRn
_ty2] <- [LHsKind GhcRn]
arg_tys
                  -> do { FixityEnv
fix_env <- TcRn FixityEnv
getFixityEnv
                        ; Bool -> TcRn Bool
forall (m :: * -> *) a. Monad m => a -> m a
return (Name
con Name -> FixityEnv -> Bool
forall a. Name -> NameEnv a -> Bool
`elemNameEnv` FixityEnv
fix_env) }
               | Bool
otherwise -> Bool -> TcRn Bool
forall (m :: * -> *) a. Monad m => a -> m a
return Bool
False

tcConArgs :: HsConDeclDetails GhcRn
          -> TcM [(TcType, HsSrcBang)]
tcConArgs :: HsConDeclDetails GhcRn -> TcM [(Kind, HsSrcBang)]
tcConArgs (PrefixCon btys :: [LHsKind GhcRn]
btys)
  = (LHsKind GhcRn -> IOEnv (Env TcGblEnv TcLclEnv) (Kind, HsSrcBang))
-> [LHsKind GhcRn] -> TcM [(Kind, HsSrcBang)]
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
mapM LHsKind GhcRn -> IOEnv (Env TcGblEnv TcLclEnv) (Kind, HsSrcBang)
tcConArg [LHsKind GhcRn]
btys
tcConArgs (InfixCon bty1 :: LHsKind GhcRn
bty1 bty2 :: LHsKind GhcRn
bty2)
  = do { (Kind, HsSrcBang)
bty1' <- LHsKind GhcRn -> IOEnv (Env TcGblEnv TcLclEnv) (Kind, HsSrcBang)
tcConArg LHsKind GhcRn
bty1
       ; (Kind, HsSrcBang)
bty2' <- LHsKind GhcRn -> IOEnv (Env TcGblEnv TcLclEnv) (Kind, HsSrcBang)
tcConArg LHsKind GhcRn
bty2
       ; [(Kind, HsSrcBang)] -> TcM [(Kind, HsSrcBang)]
forall (m :: * -> *) a. Monad m => a -> m a
return [(Kind, HsSrcBang)
bty1', (Kind, HsSrcBang)
bty2'] }
tcConArgs (RecCon fields :: Located [LConDeclField GhcRn]
fields)
  = (LHsKind GhcRn -> IOEnv (Env TcGblEnv TcLclEnv) (Kind, HsSrcBang))
-> [LHsKind GhcRn] -> TcM [(Kind, HsSrcBang)]
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
mapM LHsKind GhcRn -> IOEnv (Env TcGblEnv TcLclEnv) (Kind, HsSrcBang)
tcConArg [LHsKind GhcRn]
btys
  where
    -- We need a one-to-one mapping from field_names to btys
    combined :: [([LFieldOcc GhcRn], LHsKind GhcRn)]
combined = (LConDeclField GhcRn -> ([LFieldOcc GhcRn], LHsKind GhcRn))
-> [LConDeclField GhcRn] -> [([LFieldOcc GhcRn], LHsKind GhcRn)]
forall a b. (a -> b) -> [a] -> [b]
map (\(LConDeclField GhcRn -> Located (SrcSpanLess (LConDeclField GhcRn))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L _ f :: SrcSpanLess (LConDeclField GhcRn)
f) -> (ConDeclField GhcRn -> [LFieldOcc GhcRn]
forall pass. ConDeclField pass -> [LFieldOcc pass]
cd_fld_names SrcSpanLess (LConDeclField GhcRn)
ConDeclField GhcRn
f,ConDeclField GhcRn -> LHsKind GhcRn
forall pass. ConDeclField pass -> LBangType pass
cd_fld_type SrcSpanLess (LConDeclField GhcRn)
ConDeclField GhcRn
f))
                   (Located [LConDeclField GhcRn]
-> SrcSpanLess (Located [LConDeclField GhcRn])
forall a. HasSrcSpan a => a -> SrcSpanLess a
unLoc Located [LConDeclField GhcRn]
fields)
    explode :: ([a], b) -> [(a, b)]
explode (ns :: [a]
ns,ty :: b
ty) = [a] -> [b] -> [(a, b)]
forall a b. [a] -> [b] -> [(a, b)]
zip [a]
ns (b -> [b]
forall a. a -> [a]
repeat b
ty)
    exploded :: [(LFieldOcc GhcRn, LHsKind GhcRn)]
exploded = (([LFieldOcc GhcRn], LHsKind GhcRn)
 -> [(LFieldOcc GhcRn, LHsKind GhcRn)])
-> [([LFieldOcc GhcRn], LHsKind GhcRn)]
-> [(LFieldOcc GhcRn, LHsKind GhcRn)]
forall (t :: * -> *) a b. Foldable t => (a -> [b]) -> t a -> [b]
concatMap ([LFieldOcc GhcRn], LHsKind GhcRn)
-> [(LFieldOcc GhcRn, LHsKind GhcRn)]
forall a b. ([a], b) -> [(a, b)]
explode [([LFieldOcc GhcRn], LHsKind GhcRn)]
combined
    (_,btys :: [LHsKind GhcRn]
btys) = [(LFieldOcc GhcRn, LHsKind GhcRn)]
-> ([LFieldOcc GhcRn], [LHsKind GhcRn])
forall a b. [(a, b)] -> ([a], [b])
unzip [(LFieldOcc GhcRn, LHsKind GhcRn)]
exploded


tcConArg :: LHsType GhcRn -> TcM (TcType, HsSrcBang)
tcConArg :: LHsKind GhcRn -> IOEnv (Env TcGblEnv TcLclEnv) (Kind, HsSrcBang)
tcConArg bty :: LHsKind GhcRn
bty
  = do  { String -> SDoc -> TcRn ()
traceTc "tcConArg 1" (LHsKind GhcRn -> SDoc
forall a. Outputable a => a -> SDoc
ppr LHsKind GhcRn
bty)
        ; Kind
arg_ty <- LHsKind GhcRn -> TcM Kind
tcHsOpenType (LHsKind GhcRn -> LHsKind GhcRn
forall a. LHsType a -> LHsType a
getBangType LHsKind GhcRn
bty)
             -- Newtypes can't have unboxed types, but we check
             -- that in checkValidDataCon; this tcConArg stuff
             -- doesn't happen for GADT-style declarations
        ; String -> SDoc -> TcRn ()
traceTc "tcConArg 2" (LHsKind GhcRn -> SDoc
forall a. Outputable a => a -> SDoc
ppr LHsKind GhcRn
bty)
        ; (Kind, HsSrcBang)
-> IOEnv (Env TcGblEnv TcLclEnv) (Kind, HsSrcBang)
forall (m :: * -> *) a. Monad m => a -> m a
return (Kind
arg_ty, LHsKind GhcRn -> HsSrcBang
forall a. LHsType a -> HsSrcBang
getBangStrictness LHsKind GhcRn
bty) }

{-
Note [Infix GADT constructors]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
We do not currently have syntax to declare an infix constructor in GADT syntax,
but it makes a (small) difference to the Show instance.  So as a slightly
ad-hoc solution, we regard a GADT data constructor as infix if
  a) it is an operator symbol
  b) it has two arguments
  c) there is a fixity declaration for it
For example:
   infix 6 (:--:)
   data T a where
     (:--:) :: t1 -> t2 -> T Int


Note [Checking GADT return types]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
There is a delicacy around checking the return types of a datacon. The
central problem is dealing with a declaration like

  data T a where
    MkT :: T a -> Q a

Note that the return type of MkT is totally bogus. When creating the T
tycon, we also need to create the MkT datacon, which must have a "rejigged"
return type. That is, the MkT datacon's type must be transformed to have
a uniform return type with explicit coercions for GADT-like type parameters.
This rejigging is what rejigConRes does. The problem is, though, that checking
that the return type is appropriate is much easier when done over *Type*,
not *HsType*, and doing a call to tcMatchTy will loop because T isn't fully
defined yet.

So, we want to make rejigConRes lazy and then check the validity of
the return type in checkValidDataCon.  To do this we /always/ return a
6-tuple from rejigConRes (so that we can compute the return type from it, which
checkValidDataCon needs), but the first three fields may be bogus if
the return type isn't valid (the last equation for rejigConRes).

This is better than an earlier solution which reduced the number of
errors reported in one pass.  See Trac #7175, and #10836.
-}

-- Example
--   data instance T (b,c) where
--      TI :: forall e. e -> T (e,e)
--
-- The representation tycon looks like this:
--   data :R7T b c where
--      TI :: forall b1 c1. (b1 ~ c1) => b1 -> :R7T b1 c1
-- In this case orig_res_ty = T (e,e)

rejigConRes :: [KnotTied TyConBinder] -> KnotTied Type    -- Template for result type; e.g.
                                  -- data instance T [a] b c ...
                                  --      gives template ([a,b,c], T [a] b c)
                                  -- Type must be of kind *!
            -> [TyVar]            -- The constructor's inferred type variables
            -> [TyVar]            -- The constructor's user-written, specified
                                  -- type variables
            -> KnotTied Type      -- res_ty type must be of kind *
            -> ([TyVar],          -- Universal
                [TyVar],          -- Existential (distinct OccNames from univs)
                [TyVar],          -- The constructor's rejigged, user-written,
                                  -- inferred type variables
                [TyVar],          -- The constructor's rejigged, user-written,
                                  -- specified type variables
                [EqSpec],      -- Equality predicates
                TCvSubst)      -- Substitution to apply to argument types
        -- We don't check that the TyCon given in the ResTy is
        -- the same as the parent tycon, because checkValidDataCon will do it
-- NB: All arguments may potentially be knot-tied
rejigConRes :: [TyConBinder]
-> Kind
-> [TyVar]
-> [TyVar]
-> Kind
-> ([TyVar], [TyVar], [TyVar], [TyVar], [EqSpec], TCvSubst)
rejigConRes tmpl_bndrs :: [TyConBinder]
tmpl_bndrs res_tmpl :: Kind
res_tmpl dc_inferred_tvs :: [TyVar]
dc_inferred_tvs dc_specified_tvs :: [TyVar]
dc_specified_tvs res_ty :: Kind
res_ty
        -- E.g.  data T [a] b c where
        --         MkT :: forall x y z. T [(x,y)] z z
        -- The {a,b,c} are the tmpl_tvs, and the {x,y,z} are the dc_tvs
        --     (NB: unlike the H98 case, the dc_tvs are not all existential)
        -- Then we generate
        --      Univ tyvars     Eq-spec
        --          a              a~(x,y)
        --          b              b~z
        --          z
        -- Existentials are the leftover type vars: [x,y]
        -- The user-written type variables are what is listed in the forall:
        --   [x, y, z] (all specified). We must rejig these as well.
        --   See Note [DataCon user type variable binders] in DataCon.
        -- So we return ( [a,b,z], [x,y]
        --              , [], [x,y,z]
        --              , [a~(x,y),b~z], <arg-subst> )
  | Just subst :: TCvSubst
subst <- ASSERT( isLiftedTypeKind (tcTypeKind res_ty) )
                  ASSERT( isLiftedTypeKind (tcTypeKind res_tmpl) )
                  Kind -> Kind -> Maybe TCvSubst
tcMatchTy Kind
res_tmpl Kind
res_ty
  = let (univ_tvs :: [TyVar]
univ_tvs, raw_eqs :: [EqSpec]
raw_eqs, kind_subst :: TCvSubst
kind_subst) = [TyVar] -> [TyVar] -> TCvSubst -> ([TyVar], [EqSpec], TCvSubst)
mkGADTVars [TyVar]
tmpl_tvs [TyVar]
dc_tvs TCvSubst
subst
        raw_ex_tvs :: [TyVar]
raw_ex_tvs = [TyVar]
dc_tvs [TyVar] -> [TyVar] -> [TyVar]
forall a. Ord a => [a] -> [a] -> [a]
`minusList` [TyVar]
univ_tvs
        (arg_subst :: TCvSubst
arg_subst, substed_ex_tvs :: [TyVar]
substed_ex_tvs) = HasCallStack => TCvSubst -> [TyVar] -> (TCvSubst, [TyVar])
TCvSubst -> [TyVar] -> (TCvSubst, [TyVar])
substTyVarBndrs TCvSubst
kind_subst [TyVar]
raw_ex_tvs

        -- After rejigging the existential tyvars, the resulting substitution
        -- gives us exactly what we need to rejig the user-written tyvars,
        -- since the dcUserTyVarBinders invariant guarantees that the
        -- substitution has *all* the tyvars in its domain.
        -- See Note [DataCon user type variable binders] in DataCon.
        subst_user_tvs :: [TyVar] -> [TyVar]
subst_user_tvs = (TyVar -> TyVar) -> [TyVar] -> [TyVar]
forall a b. (a -> b) -> [a] -> [b]
map (String -> Kind -> TyVar
getTyVar "rejigConRes" (Kind -> TyVar) -> (TyVar -> Kind) -> TyVar -> TyVar
forall b c a. (b -> c) -> (a -> b) -> a -> c
. TCvSubst -> TyVar -> Kind
substTyVar TCvSubst
arg_subst)
        substed_inferred_tvs :: [TyVar]
substed_inferred_tvs  = [TyVar] -> [TyVar]
subst_user_tvs [TyVar]
dc_inferred_tvs
        substed_specified_tvs :: [TyVar]
substed_specified_tvs = [TyVar] -> [TyVar]
subst_user_tvs [TyVar]
dc_specified_tvs

        substed_eqs :: [EqSpec]
substed_eqs = (EqSpec -> EqSpec) -> [EqSpec] -> [EqSpec]
forall a b. (a -> b) -> [a] -> [b]
map (TCvSubst -> EqSpec -> EqSpec
substEqSpec TCvSubst
arg_subst) [EqSpec]
raw_eqs
    in
    ([TyVar]
univ_tvs, [TyVar]
substed_ex_tvs, [TyVar]
substed_inferred_tvs, [TyVar]
substed_specified_tvs,
     [EqSpec]
substed_eqs, TCvSubst
arg_subst)

  | Bool
otherwise
        -- If the return type of the data constructor doesn't match the parent
        -- type constructor, or the arity is wrong, the tcMatchTy will fail
        --    e.g   data T a b where
        --            T1 :: Maybe a   -- Wrong tycon
        --            T2 :: T [a]     -- Wrong arity
        -- We are detect that later, in checkValidDataCon, but meanwhile
        -- we must do *something*, not just crash.  So we do something simple
        -- albeit bogus, relying on checkValidDataCon to check the
        --  bad-result-type error before seeing that the other fields look odd
        -- See Note [Checking GADT return types]
  = ([TyVar]
tmpl_tvs, [TyVar]
dc_tvs [TyVar] -> [TyVar] -> [TyVar]
forall a. Ord a => [a] -> [a] -> [a]
`minusList` [TyVar]
tmpl_tvs, [TyVar]
dc_inferred_tvs, [TyVar]
dc_specified_tvs,
     [], TCvSubst
emptyTCvSubst)
  where
    dc_tvs :: [TyVar]
dc_tvs   = [TyVar]
dc_inferred_tvs [TyVar] -> [TyVar] -> [TyVar]
forall a. [a] -> [a] -> [a]
++ [TyVar]
dc_specified_tvs
    tmpl_tvs :: [TyVar]
tmpl_tvs = [TyConBinder] -> [TyVar]
forall tv argf. [VarBndr tv argf] -> [tv]
binderVars [TyConBinder]
tmpl_bndrs

{- Note [mkGADTVars]
~~~~~~~~~~~~~~~~~~~~
Running example:

data T (k1 :: *) (k2 :: *) (a :: k2) (b :: k2) where
  MkT :: forall (x1 : *) (y :: x1) (z :: *).
         T x1 * (Proxy (y :: x1), z) z

We need the rejigged type to be

  MkT :: forall (x1 :: *) (k2 :: *) (a :: k2) (b :: k2).
         forall (y :: x1) (z :: *).
         (k2 ~ *, a ~ (Proxy x1 y, z), b ~ z)
      => T x1 k2 a b

You might naively expect that z should become a universal tyvar,
not an existential. (After all, x1 becomes a universal tyvar.)
But z has kind * while b has kind k2, so the return type
   T x1 k2 a z
is ill-kinded.  Another way to say it is this: the universal
tyvars must have exactly the same kinds as the tyConTyVars.

So we need an existential tyvar and a heterogeneous equality
constraint. (The b ~ z is a bit redundant with the k2 ~ * that
comes before in that b ~ z implies k2 ~ *. I'm sure we could do
some analysis that could eliminate k2 ~ *. But we don't do this
yet.)

The data con signature has already been fully kind-checked.
The return type

  T x1 * (Proxy (y :: x1), z) z
becomes
  qtkvs    = [x1 :: *, y :: x1, z :: *]
  res_tmpl = T x1 * (Proxy x1 y, z) z

We start off by matching (T k1 k2 a b) with (T x1 * (Proxy x1 y, z) z). We
know this match will succeed because of the validity check (actually done
later, but laziness saves us -- see Note [Checking GADT return types]).
Thus, we get

  subst := { k1 |-> x1, k2 |-> *, a |-> (Proxy x1 y, z), b |-> z }

Now, we need to figure out what the GADT equalities should be. In this case,
we *don't* want (k1 ~ x1) to be a GADT equality: it should just be a
renaming. The others should be GADT equalities. We also need to make
sure that the universally-quantified variables of the datacon match up
with the tyvars of the tycon, as required for Core context well-formedness.
(This last bit is why we have to rejig at all!)

`choose` walks down the tycon tyvars, figuring out what to do with each one.
It carries two substitutions:
  - t_sub's domain is *template* or *tycon* tyvars, mapping them to variables
    mentioned in the datacon signature.
  - r_sub's domain is *result* tyvars, names written by the programmer in
    the datacon signature. The final rejigged type will use these names, but
    the subst is still needed because sometimes the printed name of these variables
    is different. (See choose_tv_name, below.)

Before explaining the details of `choose`, let's just look at its operation
on our example:

  choose [] [] {} {} [k1, k2, a, b]
  -->          -- first branch of `case` statement
  choose
    univs:    [x1 :: *]
    eq_spec:  []
    t_sub:    {k1 |-> x1}
    r_sub:    {x1 |-> x1}
    t_tvs:    [k2, a, b]
  -->          -- second branch of `case` statement
  choose
    univs:    [k2 :: *, x1 :: *]
    eq_spec:  [k2 ~ *]
    t_sub:    {k1 |-> x1, k2 |-> k2}
    r_sub:    {x1 |-> x1}
    t_tvs:    [a, b]
  -->          -- second branch of `case` statement
  choose
    univs:    [a :: k2, k2 :: *, x1 :: *]
    eq_spec:  [ a ~ (Proxy x1 y, z)
              , k2 ~ * ]
    t_sub:    {k1 |-> x1, k2 |-> k2, a |-> a}
    r_sub:    {x1 |-> x1}
    t_tvs:    [b]
  -->          -- second branch of `case` statement
  choose
    univs:    [b :: k2, a :: k2, k2 :: *, x1 :: *]
    eq_spec:  [ b ~ z
              , a ~ (Proxy x1 y, z)
              , k2 ~ * ]
    t_sub:    {k1 |-> x1, k2 |-> k2, a |-> a, b |-> z}
    r_sub:    {x1 |-> x1}
    t_tvs:    []
  -->          -- end of recursion
  ( [x1 :: *, k2 :: *, a :: k2, b :: k2]
  , [k2 ~ *, a ~ (Proxy x1 y, z), b ~ z]
  , {x1 |-> x1} )

`choose` looks up each tycon tyvar in the matching (it *must* be matched!).

* If it finds a bare result tyvar (the first branch of the `case`
  statement), it checks to make sure that the result tyvar isn't yet
  in the list of univ_tvs.  If it is in that list, then we have a
  repeated variable in the return type, and we in fact need a GADT
  equality.

* It then checks to make sure that the kind of the result tyvar
  matches the kind of the template tyvar. This check is what forces
  `z` to be existential, as it should be, explained above.

* Assuming no repeated variables or kind-changing, we wish to use the
  variable name given in the datacon signature (that is, `x1` not
  `k1`), not the tycon signature (which may have been made up by
  GHC). So, we add a mapping from the tycon tyvar to the result tyvar
  to t_sub.

* If we discover that a mapping in `subst` gives us a non-tyvar (the
  second branch of the `case` statement), then we have a GADT equality
  to create.  We create a fresh equality, but we don't extend any
  substitutions. The template variable substitution is meant for use
  in universal tyvar kinds, and these shouldn't be affected by any
  GADT equalities.

This whole algorithm is quite delicate, indeed. I (Richard E.) see two ways
of simplifying it:

1) The first branch of the `case` statement is really an optimization, used
in order to get fewer GADT equalities. It might be possible to make a GADT
equality for *every* univ. tyvar, even if the equality is trivial, and then
either deal with the bigger type or somehow reduce it later.

2) This algorithm strives to use the names for type variables as specified
by the user in the datacon signature. If we always used the tycon tyvar
names, for example, this would be simplified. This change would almost
certainly degrade error messages a bit, though.
-}

-- ^ From information about a source datacon definition, extract out
-- what the universal variables and the GADT equalities should be.
-- See Note [mkGADTVars].
mkGADTVars :: [TyVar]    -- ^ The tycon vars
           -> [TyVar]    -- ^ The datacon vars
           -> TCvSubst   -- ^ The matching between the template result type
                         -- and the actual result type
           -> ( [TyVar]
              , [EqSpec]
              , TCvSubst ) -- ^ The univ. variables, the GADT equalities,
                           -- and a subst to apply to the GADT equalities
                           -- and existentials.
mkGADTVars :: [TyVar] -> [TyVar] -> TCvSubst -> ([TyVar], [EqSpec], TCvSubst)
mkGADTVars tmpl_tvs :: [TyVar]
tmpl_tvs dc_tvs :: [TyVar]
dc_tvs subst :: TCvSubst
subst
  = [TyVar]
-> [EqSpec]
-> TCvSubst
-> TCvSubst
-> [TyVar]
-> ([TyVar], [EqSpec], TCvSubst)
choose [] [] TCvSubst
empty_subst TCvSubst
empty_subst [TyVar]
tmpl_tvs
  where
    in_scope :: InScopeSet
in_scope = TcTyCoVarSet -> InScopeSet
mkInScopeSet ([TyVar] -> TcTyCoVarSet
mkVarSet [TyVar]
tmpl_tvs TcTyCoVarSet -> TcTyCoVarSet -> TcTyCoVarSet
`unionVarSet` [TyVar] -> TcTyCoVarSet
mkVarSet [TyVar]
dc_tvs)
               InScopeSet -> InScopeSet -> InScopeSet
`unionInScope` TCvSubst -> InScopeSet
getTCvInScope TCvSubst
subst
    empty_subst :: TCvSubst
empty_subst = InScopeSet -> TCvSubst
mkEmptyTCvSubst InScopeSet
in_scope

    choose :: [TyVar]           -- accumulator of univ tvs, reversed
           -> [EqSpec]          -- accumulator of GADT equalities, reversed
           -> TCvSubst          -- template substitution
           -> TCvSubst          -- res. substitution
           -> [TyVar]           -- template tvs (the univ tvs passed in)
           -> ( [TyVar]         -- the univ_tvs
              , [EqSpec]        -- GADT equalities
              , TCvSubst )       -- a substitution to fix kinds in ex_tvs

    choose :: [TyVar]
-> [EqSpec]
-> TCvSubst
-> TCvSubst
-> [TyVar]
-> ([TyVar], [EqSpec], TCvSubst)
choose univs :: [TyVar]
univs eqs :: [EqSpec]
eqs _t_sub :: TCvSubst
_t_sub r_sub :: TCvSubst
r_sub []
      = ([TyVar] -> [TyVar]
forall a. [a] -> [a]
reverse [TyVar]
univs, [EqSpec] -> [EqSpec]
forall a. [a] -> [a]
reverse [EqSpec]
eqs, TCvSubst
r_sub)
    choose univs :: [TyVar]
univs eqs :: [EqSpec]
eqs t_sub :: TCvSubst
t_sub r_sub :: TCvSubst
r_sub (t_tv :: TyVar
t_tv:t_tvs :: [TyVar]
t_tvs)
      | Just r_ty :: Kind
r_ty <- TCvSubst -> TyVar -> Maybe Kind
lookupTyVar TCvSubst
subst TyVar
t_tv
      = case Kind -> Maybe TyVar
getTyVar_maybe Kind
r_ty of
          Just r_tv :: TyVar
r_tv
            |  Bool -> Bool
not (TyVar
r_tv TyVar -> [TyVar] -> Bool
forall (t :: * -> *) a. (Foldable t, Eq a) => a -> t a -> Bool
`elem` [TyVar]
univs)
            ,  TyVar -> Kind
tyVarKind TyVar
r_tv Kind -> Kind -> Bool
`eqType` (HasCallStack => TCvSubst -> Kind -> Kind
TCvSubst -> Kind -> Kind
substTy TCvSubst
t_sub (TyVar -> Kind
tyVarKind TyVar
t_tv))
            -> -- simple, well-kinded variable substitution.
               [TyVar]
-> [EqSpec]
-> TCvSubst
-> TCvSubst
-> [TyVar]
-> ([TyVar], [EqSpec], TCvSubst)
choose (TyVar
r_tvTyVar -> [TyVar] -> [TyVar]
forall a. a -> [a] -> [a]
:[TyVar]
univs) [EqSpec]
eqs
                      (TCvSubst -> TyVar -> Kind -> TCvSubst
extendTvSubst TCvSubst
t_sub TyVar
t_tv Kind
r_ty')
                      (TCvSubst -> TyVar -> Kind -> TCvSubst
extendTvSubst TCvSubst
r_sub TyVar
r_tv Kind
r_ty')
                      [TyVar]
t_tvs
            where
              r_tv1 :: TyVar
r_tv1  = TyVar -> Name -> TyVar
setTyVarName TyVar
r_tv (TyVar -> TyVar -> Name
choose_tv_name TyVar
r_tv TyVar
t_tv)
              r_ty' :: Kind
r_ty'  = TyVar -> Kind
mkTyVarTy TyVar
r_tv1

               -- Not a simple substitution: make an equality predicate
          _ -> [TyVar]
-> [EqSpec]
-> TCvSubst
-> TCvSubst
-> [TyVar]
-> ([TyVar], [EqSpec], TCvSubst)
choose (TyVar
t_tv'TyVar -> [TyVar] -> [TyVar]
forall a. a -> [a] -> [a]
:[TyVar]
univs) (TyVar -> Kind -> EqSpec
mkEqSpec TyVar
t_tv' Kind
r_ty EqSpec -> [EqSpec] -> [EqSpec]
forall a. a -> [a] -> [a]
: [EqSpec]
eqs)
                      (TCvSubst -> TyVar -> Kind -> TCvSubst
extendTvSubst TCvSubst
t_sub TyVar
t_tv (TyVar -> Kind
mkTyVarTy TyVar
t_tv'))
                         -- We've updated the kind of t_tv,
                         -- so add it to t_sub (Trac #14162)
                      TCvSubst
r_sub [TyVar]
t_tvs
            where
              t_tv' :: TyVar
t_tv' = (Kind -> Kind) -> TyVar -> TyVar
updateTyVarKind (HasCallStack => TCvSubst -> Kind -> Kind
TCvSubst -> Kind -> Kind
substTy TCvSubst
t_sub) TyVar
t_tv

      | Bool
otherwise
      = String -> SDoc -> ([TyVar], [EqSpec], TCvSubst)
forall a. HasCallStack => String -> SDoc -> a
pprPanic "mkGADTVars" ([TyVar] -> SDoc
forall a. Outputable a => a -> SDoc
ppr [TyVar]
tmpl_tvs SDoc -> SDoc -> SDoc
$$ TCvSubst -> SDoc
forall a. Outputable a => a -> SDoc
ppr TCvSubst
subst)

      -- choose an appropriate name for a univ tyvar.
      -- This *must* preserve the Unique of the result tv, so that we
      -- can detect repeated variables. It prefers user-specified names
      -- over system names. A result variable with a system name can
      -- happen with GHC-generated implicit kind variables.
    choose_tv_name :: TyVar -> TyVar -> Name
    choose_tv_name :: TyVar -> TyVar -> Name
choose_tv_name r_tv :: TyVar
r_tv t_tv :: TyVar
t_tv
      | Name -> Bool
isSystemName Name
r_tv_name
      = Name -> Unique -> Name
setNameUnique Name
t_tv_name (Name -> Unique
forall a. Uniquable a => a -> Unique
getUnique Name
r_tv_name)

      | Bool
otherwise
      = Name
r_tv_name

      where
        r_tv_name :: Name
r_tv_name = TyVar -> Name
forall a. NamedThing a => a -> Name
getName TyVar
r_tv
        t_tv_name :: Name
t_tv_name = TyVar -> Name
forall a. NamedThing a => a -> Name
getName TyVar
t_tv

{-
Note [Substitution in template variables kinds]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

data G (a :: Maybe k) where
  MkG :: G Nothing

With explicit kind variables

data G k (a :: Maybe k) where
  MkG :: G k1 (Nothing k1)

Note how k1 is distinct from k. So, when we match the template
`G k a` against `G k1 (Nothing k1)`, we get a subst
[ k |-> k1, a |-> Nothing k1 ]. Even though this subst has two
mappings, we surely don't want to add (k, k1) to the list of
GADT equalities -- that would be overly complex and would create
more untouchable variables than we need. So, when figuring out
which tyvars are GADT-like and which aren't (the fundamental
job of `choose`), we want to treat `k` as *not* GADT-like.
Instead, we wish to substitute in `a`'s kind, to get (a :: Maybe k1)
instead of (a :: Maybe k). This is the reason for dealing
with a substitution in here.

However, we do not *always* want to substitute. Consider

data H (a :: k) where
  MkH :: H Int

With explicit kind variables:

data H k (a :: k) where
  MkH :: H * Int

Here, we have a kind-indexed GADT. The subst in question is
[ k |-> *, a |-> Int ]. Now, we *don't* want to substitute in `a`'s
kind, because that would give a constructor with the type

MkH :: forall (k :: *) (a :: *). (k ~ *) -> (a ~ Int) -> H k a

The problem here is that a's kind is wrong -- it needs to be k, not *!
So, if the matching for a variable is anything but another bare variable,
we drop the mapping from the substitution before proceeding. This
was not an issue before kind-indexed GADTs because this case could
never happen.

************************************************************************
*                                                                      *
                Validity checking
*                                                                      *
************************************************************************

Validity checking is done once the mutually-recursive knot has been
tied, so we can look at things freely.
-}

checkValidTyCl :: TyCon -> TcM [TyCon]
-- The returned list is either a singleton (if valid)
-- or a list of "fake tycons" (if not); the fake tycons
-- include any implicits, like promoted data constructors
-- See Note [Recover from validity error]
checkValidTyCl :: TyCon -> TcM [TyCon]
checkValidTyCl tc :: TyCon
tc
  = SrcSpan -> TcM [TyCon] -> TcM [TyCon]
forall a. SrcSpan -> TcRn a -> TcRn a
setSrcSpan (TyCon -> SrcSpan
forall a. NamedThing a => a -> SrcSpan
getSrcSpan TyCon
tc) (TcM [TyCon] -> TcM [TyCon]) -> TcM [TyCon] -> TcM [TyCon]
forall a b. (a -> b) -> a -> b
$
    TyCon -> TcM [TyCon] -> TcM [TyCon]
forall a. TyCon -> TcM a -> TcM a
addTyConCtxt TyCon
tc (TcM [TyCon] -> TcM [TyCon]) -> TcM [TyCon] -> TcM [TyCon]
forall a b. (a -> b) -> a -> b
$
    TcM [TyCon] -> TcM [TyCon] -> TcM [TyCon]
forall r. TcRn r -> TcRn r -> TcRn r
recoverM TcM [TyCon]
recovery_code
             (do { String -> SDoc -> TcRn ()
traceTc "Starting validity for tycon" (TyCon -> SDoc
forall a. Outputable a => a -> SDoc
ppr TyCon
tc)
                 ; TyCon -> TcRn ()
checkValidTyCon TyCon
tc
                 ; String -> SDoc -> TcRn ()
traceTc "Done validity for tycon" (TyCon -> SDoc
forall a. Outputable a => a -> SDoc
ppr TyCon
tc)
                 ; [TyCon] -> TcM [TyCon]
forall (m :: * -> *) a. Monad m => a -> m a
return [TyCon
tc] })
  where
    recovery_code :: TcM [TyCon]
recovery_code -- See Note [Recover from validity error]
      = do { String -> SDoc -> TcRn ()
traceTc "Aborted validity for tycon" (TyCon -> SDoc
forall a. Outputable a => a -> SDoc
ppr TyCon
tc)
           ; [TyCon] -> TcM [TyCon]
forall (m :: * -> *) a. Monad m => a -> m a
return ((TyThing -> [TyCon]) -> [TyThing] -> [TyCon]
forall (t :: * -> *) a b. Foldable t => (a -> [b]) -> t a -> [b]
concatMap TyThing -> [TyCon]
mk_fake_tc ([TyThing] -> [TyCon]) -> [TyThing] -> [TyCon]
forall a b. (a -> b) -> a -> b
$
                     TyCon -> TyThing
ATyCon TyCon
tc TyThing -> [TyThing] -> [TyThing]
forall a. a -> [a] -> [a]
: TyCon -> [TyThing]
implicitTyConThings TyCon
tc) }

    mk_fake_tc :: TyThing -> [TyCon]
mk_fake_tc (ATyCon tc :: TyCon
tc)
      | TyCon -> Bool
isClassTyCon TyCon
tc = [TyCon
tc]   -- Ugh! Note [Recover from validity error]
      | Bool
otherwise       = [TyCon -> TyCon
makeRecoveryTyCon TyCon
tc]
    mk_fake_tc (AConLike (RealDataCon dc :: DataCon
dc))
                        = [TyCon -> TyCon
makeRecoveryTyCon (DataCon -> TyCon
promoteDataCon DataCon
dc)]
    mk_fake_tc _        = []

{- Note [Recover from validity error]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
We recover from a validity error in a type or class, which allows us
to report multiple validity errors. In the failure case we return a
TyCon of the right kind, but with no interesting behaviour
(makeRecoveryTyCon). Why?  Suppose we have
   type T a = Fun
where Fun is a type family of arity 1.  The RHS is invalid, but we
want to go on checking validity of subsequent type declarations.
So we replace T with an abstract TyCon which will do no harm.
See indexed-types/should_fail/BadSock and Trac #10896

Some notes:

* We must make fakes for promoted DataCons too. Consider (Trac #15215)
      data T a = MkT ...
      data S a = ...T...MkT....
  If there is an error in the definition of 'T' we add a "fake type
  constructor" to the type environment, so that we can continue to
  typecheck 'S'.  But we /were not/ adding a fake anything for 'MkT'
  and so there was an internal error when we met 'MkT' in the body of
  'S'.

* Painfully, we *don't* want to do this for classes.
  Consider tcfail041:
     class (?x::Int) => C a where ...
     instance C Int
  The class is invalid because of the superclass constraint.  But
  we still want it to look like a /class/, else the instance bleats
  that the instance is mal-formed because it hasn't got a class in
  the head.

  This is really bogus; now we have in scope a Class that is invalid
  in some way, with unknown downstream consequences.  A better
  alterantive might be to make a fake class TyCon.  A job for another day.
-}

-------------------------
-- For data types declared with record syntax, we require
-- that each constructor that has a field 'f'
--      (a) has the same result type
--      (b) has the same type for 'f'
-- module alpha conversion of the quantified type variables
-- of the constructor.
--
-- Note that we allow existentials to match because the
-- fields can never meet. E.g
--      data T where
--        T1 { f1 :: b, f2 :: a, f3 ::Int } :: T
--        T2 { f1 :: c, f2 :: c, f3 ::Int } :: T
-- Here we do not complain about f1,f2 because they are existential

checkValidTyCon :: TyCon -> TcM ()
checkValidTyCon :: TyCon -> TcRn ()
checkValidTyCon tc :: TyCon
tc
  | TyCon -> Bool
isPrimTyCon TyCon
tc   -- Happens when Haddock'ing GHC.Prim
  = () -> TcRn ()
forall (m :: * -> *) a. Monad m => a -> m a
return ()

  | Bool
otherwise
  = do { String -> SDoc -> TcRn ()
traceTc "checkValidTyCon" (TyCon -> SDoc
forall a. Outputable a => a -> SDoc
ppr TyCon
tc SDoc -> SDoc -> SDoc
$$ Maybe Class -> SDoc
forall a. Outputable a => a -> SDoc
ppr (TyCon -> Maybe Class
tyConClass_maybe TyCon
tc))
       ; if | Just cl :: Class
cl <- TyCon -> Maybe Class
tyConClass_maybe TyCon
tc
              -> Class -> TcRn ()
checkValidClass Class
cl

            | Just syn_rhs :: Kind
syn_rhs <- TyCon -> Maybe Kind
synTyConRhs_maybe TyCon
tc
              -> do { UserTypeCtxt -> Kind -> TcRn ()
checkValidType UserTypeCtxt
syn_ctxt Kind
syn_rhs
                    ; UserTypeCtxt -> Kind -> TcRn ()
checkTySynRhs UserTypeCtxt
syn_ctxt Kind
syn_rhs }

            | Just fam_flav :: FamTyConFlav
fam_flav <- TyCon -> Maybe FamTyConFlav
famTyConFlav_maybe TyCon
tc
              -> case FamTyConFlav
fam_flav of
               { ClosedSynFamilyTyCon (Just ax :: CoAxiom Branched
ax)
                   -> TyCon -> TcRn () -> TcRn ()
forall a. TyCon -> TcM a -> TcM a
tcAddClosedTypeFamilyDeclCtxt TyCon
tc (TcRn () -> TcRn ()) -> TcRn () -> TcRn ()
forall a b. (a -> b) -> a -> b
$
                      CoAxiom Branched -> TcRn ()
checkValidCoAxiom CoAxiom Branched
ax
               ; ClosedSynFamilyTyCon Nothing   -> () -> TcRn ()
forall (m :: * -> *) a. Monad m => a -> m a
return ()
               ; AbstractClosedSynFamilyTyCon ->
                 do { Bool
hsBoot <- TcRn Bool
tcIsHsBootOrSig
                    ; Bool -> SDoc -> TcRn ()
checkTc Bool
hsBoot (SDoc -> TcRn ()) -> SDoc -> TcRn ()
forall a b. (a -> b) -> a -> b
$
                      String -> SDoc
text "You may define an abstract closed type family" SDoc -> SDoc -> SDoc
$$
                      String -> SDoc
text "only in a .hs-boot file" }
               ; DataFamilyTyCon {}           -> () -> TcRn ()
forall (m :: * -> *) a. Monad m => a -> m a
return ()
               ; OpenSynFamilyTyCon           -> () -> TcRn ()
forall (m :: * -> *) a. Monad m => a -> m a
return ()
               ; BuiltInSynFamTyCon _         -> () -> TcRn ()
forall (m :: * -> *) a. Monad m => a -> m a
return () }

             | Bool
otherwise -> do
               { -- Check the context on the data decl
                 String -> SDoc -> TcRn ()
traceTc "cvtc1" (TyCon -> SDoc
forall a. Outputable a => a -> SDoc
ppr TyCon
tc)
               ; UserTypeCtxt -> [Kind] -> TcRn ()
checkValidTheta (Name -> UserTypeCtxt
DataTyCtxt Name
name) (TyCon -> [Kind]
tyConStupidTheta TyCon
tc)

               ; String -> SDoc -> TcRn ()
traceTc "cvtc2" (TyCon -> SDoc
forall a. Outputable a => a -> SDoc
ppr TyCon
tc)

               ; DynFlags
dflags          <- IOEnv (Env TcGblEnv TcLclEnv) DynFlags
forall (m :: * -> *). HasDynFlags m => m DynFlags
getDynFlags
               ; Bool
existential_ok  <- Extension -> TcRn Bool
forall gbl lcl. Extension -> TcRnIf gbl lcl Bool
xoptM Extension
LangExt.ExistentialQuantification
               ; Bool
gadt_ok         <- Extension -> TcRn Bool
forall gbl lcl. Extension -> TcRnIf gbl lcl Bool
xoptM Extension
LangExt.GADTs
               ; let ex_ok :: Bool
ex_ok = Bool
existential_ok Bool -> Bool -> Bool
|| Bool
gadt_ok
                     -- Data cons can have existential context
               ; (DataCon -> TcRn ()) -> [DataCon] -> TcRn ()
forall (t :: * -> *) (m :: * -> *) a b.
(Foldable t, Monad m) =>
(a -> m b) -> t a -> m ()
mapM_ (DynFlags -> Bool -> TyCon -> DataCon -> TcRn ()
checkValidDataCon DynFlags
dflags Bool
ex_ok TyCon
tc) [DataCon]
data_cons
               ; (FieldLabel -> TcRn ()) -> [FieldLabel] -> TcRn ()
forall (t :: * -> *) (m :: * -> *) a b.
(Foldable t, Monad m) =>
(a -> m b) -> t a -> m ()
mapM_ ([DataCon] -> FieldLabel -> TcRn ()
checkPartialRecordField [DataCon]
data_cons) (TyCon -> [FieldLabel]
tyConFieldLabels TyCon
tc)

                -- Check that fields with the same name share a type
               ; (NonEmpty (FieldLabel, DataCon) -> TcRn ())
-> [NonEmpty (FieldLabel, DataCon)] -> TcRn ()
forall (t :: * -> *) (m :: * -> *) a b.
(Foldable t, Monad m) =>
(a -> m b) -> t a -> m ()
mapM_ NonEmpty (FieldLabel, DataCon) -> TcRn ()
forall a. NonEmpty (FieldLbl a, DataCon) -> TcRn ()
check_fields [NonEmpty (FieldLabel, DataCon)]
groups }}
  where
    syn_ctxt :: UserTypeCtxt
syn_ctxt  = Name -> UserTypeCtxt
TySynCtxt Name
name
    name :: Name
name      = TyCon -> Name
tyConName TyCon
tc
    data_cons :: [DataCon]
data_cons = TyCon -> [DataCon]
tyConDataCons TyCon
tc

    groups :: [NonEmpty (FieldLabel, DataCon)]
groups = ((FieldLabel, DataCon) -> (FieldLabel, DataCon) -> Ordering)
-> [(FieldLabel, DataCon)] -> [NonEmpty (FieldLabel, DataCon)]
forall a. (a -> a -> Ordering) -> [a] -> [NonEmpty a]
equivClasses (FieldLabel, DataCon) -> (FieldLabel, DataCon) -> Ordering
forall a b a b. (FieldLbl a, b) -> (FieldLbl a, b) -> Ordering
cmp_fld ((DataCon -> [(FieldLabel, DataCon)])
-> [DataCon] -> [(FieldLabel, DataCon)]
forall (t :: * -> *) a b. Foldable t => (a -> [b]) -> t a -> [b]
concatMap DataCon -> [(FieldLabel, DataCon)]
get_fields [DataCon]
data_cons)
    cmp_fld :: (FieldLbl a, b) -> (FieldLbl a, b) -> Ordering
cmp_fld (f1 :: FieldLbl a
f1,_) (f2 :: FieldLbl a
f2,_) = FieldLbl a -> FieldLabelString
forall a. FieldLbl a -> FieldLabelString
flLabel FieldLbl a
f1 FieldLabelString -> FieldLabelString -> Ordering
forall a. Ord a => a -> a -> Ordering
`compare` FieldLbl a -> FieldLabelString
forall a. FieldLbl a -> FieldLabelString
flLabel FieldLbl a
f2
    get_fields :: DataCon -> [(FieldLabel, DataCon)]
get_fields con :: DataCon
con = DataCon -> [FieldLabel]
dataConFieldLabels DataCon
con [FieldLabel] -> [DataCon] -> [(FieldLabel, DataCon)]
forall a b. [a] -> [b] -> [(a, b)]
`zip` DataCon -> [DataCon]
forall a. a -> [a]
repeat DataCon
con
        -- dataConFieldLabels may return the empty list, which is fine

    -- See Note [GADT record selectors] in TcTyDecls
    -- We must check (a) that the named field has the same
    --                   type in each constructor
    --               (b) that those constructors have the same result type
    --
    -- However, the constructors may have differently named type variable
    -- and (worse) we don't know how the correspond to each other.  E.g.
    --     C1 :: forall a b. { f :: a, g :: b } -> T a b
    --     C2 :: forall d c. { f :: c, g :: c } -> T c d
    --
    -- So what we do is to ust Unify.tcMatchTys to compare the first candidate's
    -- result type against other candidates' types BOTH WAYS ROUND.
    -- If they magically agrees, take the substitution and
    -- apply them to the latter ones, and see if they match perfectly.
    check_fields :: NonEmpty (FieldLbl a, DataCon) -> TcRn ()
check_fields ((label :: FieldLbl a
label, con1 :: DataCon
con1) :| other_fields :: [(FieldLbl a, DataCon)]
other_fields)
        -- These fields all have the same name, but are from
        -- different constructors in the data type
        = TcRn () -> TcRn () -> TcRn ()
forall r. TcRn r -> TcRn r -> TcRn r
recoverM (() -> TcRn ()
forall (m :: * -> *) a. Monad m => a -> m a
return ()) (TcRn () -> TcRn ()) -> TcRn () -> TcRn ()
forall a b. (a -> b) -> a -> b
$ ((FieldLbl a, DataCon) -> TcRn ())
-> [(FieldLbl a, DataCon)] -> TcRn ()
forall (t :: * -> *) (m :: * -> *) a b.
(Foldable t, Monad m) =>
(a -> m b) -> t a -> m ()
mapM_ (FieldLbl a, DataCon) -> TcRn ()
checkOne [(FieldLbl a, DataCon)]
other_fields
                -- Check that all the fields in the group have the same type
                -- NB: this check assumes that all the constructors of a given
                -- data type use the same type variables
        where
        (_, _, _, res1 :: Kind
res1) = DataCon -> ([TyVar], [Kind], [Kind], Kind)
dataConSig DataCon
con1
        fty1 :: Kind
fty1 = DataCon -> FieldLabelString -> Kind
dataConFieldType DataCon
con1 FieldLabelString
lbl
        lbl :: FieldLabelString
lbl = FieldLbl a -> FieldLabelString
forall a. FieldLbl a -> FieldLabelString
flLabel FieldLbl a
label

        checkOne :: (FieldLbl a, DataCon) -> TcRn ()
checkOne (_, con2 :: DataCon
con2)    -- Do it both ways to ensure they are structurally identical
            = do { FieldLabelString
-> DataCon -> DataCon -> Kind -> Kind -> Kind -> Kind -> TcRn ()
checkFieldCompat FieldLabelString
lbl DataCon
con1 DataCon
con2 Kind
res1 Kind
res2 Kind
fty1 Kind
fty2
                 ; FieldLabelString
-> DataCon -> DataCon -> Kind -> Kind -> Kind -> Kind -> TcRn ()
checkFieldCompat FieldLabelString
lbl DataCon
con2 DataCon
con1 Kind
res2 Kind
res1 Kind
fty2 Kind
fty1 }
            where
                (_, _, _, res2 :: Kind
res2) = DataCon -> ([TyVar], [Kind], [Kind], Kind)
dataConSig DataCon
con2
                fty2 :: Kind
fty2 = DataCon -> FieldLabelString -> Kind
dataConFieldType DataCon
con2 FieldLabelString
lbl

checkPartialRecordField :: [DataCon] -> FieldLabel -> TcM ()
-- Checks the partial record field selector, and warns.
-- See Note [Checking partial record field]
checkPartialRecordField :: [DataCon] -> FieldLabel -> TcRn ()
checkPartialRecordField all_cons :: [DataCon]
all_cons fld :: FieldLabel
fld
  = SrcSpan -> TcRn () -> TcRn ()
forall a. SrcSpan -> TcRn a -> TcRn a
setSrcSpan SrcSpan
loc (TcRn () -> TcRn ()) -> TcRn () -> TcRn ()
forall a b. (a -> b) -> a -> b
$
      WarningFlag -> Bool -> SDoc -> TcRn ()
warnIfFlag WarningFlag
Opt_WarnPartialFields
        (Bool -> Bool
not Bool
is_exhaustive Bool -> Bool -> Bool
&& Bool -> Bool
not (OccName -> Bool
startsWithUnderscore OccName
occ_name))
        ([SDoc] -> SDoc
sep [String -> SDoc
text "Use of partial record field selector" SDoc -> SDoc -> SDoc
<> SDoc
colon,
              Int -> SDoc -> SDoc
nest 2 (SDoc -> SDoc) -> SDoc -> SDoc
forall a b. (a -> b) -> a -> b
$ SDoc -> SDoc
quotes (OccName -> SDoc
forall a. Outputable a => a -> SDoc
ppr OccName
occ_name)])
  where
    sel_name :: Name
sel_name = FieldLabel -> Name
forall a. FieldLbl a -> a
flSelector FieldLabel
fld
    loc :: SrcSpan
loc    = Name -> SrcSpan
forall a. NamedThing a => a -> SrcSpan
getSrcSpan Name
sel_name
    occ_name :: OccName
occ_name = Name -> OccName
forall a. NamedThing a => a -> OccName
getOccName Name
sel_name

    (cons_with_field :: [DataCon]
cons_with_field, cons_without_field :: [DataCon]
cons_without_field) = (DataCon -> Bool) -> [DataCon] -> ([DataCon], [DataCon])
forall a. (a -> Bool) -> [a] -> ([a], [a])
partition DataCon -> Bool
has_field [DataCon]
all_cons
    has_field :: DataCon -> Bool
has_field con :: DataCon
con = FieldLabel
fld FieldLabel -> [FieldLabel] -> Bool
forall (t :: * -> *) a. (Foldable t, Eq a) => a -> t a -> Bool
`elem` (DataCon -> [FieldLabel]
dataConFieldLabels DataCon
con)
    is_exhaustive :: Bool
is_exhaustive = (DataCon -> Bool) -> [DataCon] -> Bool
forall (t :: * -> *) a. Foldable t => (a -> Bool) -> t a -> Bool
all