{-# LANGUAGE RankNTypes     #-}
{-# LANGUAGE TypeFamilies   #-}
{-# LANGUAGE BlockArguments #-}

{-# OPTIONS_GHC -Wno-incomplete-record-updates #-}

{-
(c) The University of Glasgow 2006
(c) The GRASP/AQUA Project, Glasgow University, 1992-1998

-}

-- | Typecheck arrow notation
module GHC.Tc.Gen.Arrow ( tcProc ) where

import GHC.Prelude

import {-# SOURCE #-}   GHC.Tc.Gen.Expr( tcCheckMonoExpr, tcInferRho, tcSyntaxOp
                                       , tcCheckPolyExpr )

import GHC.Hs
import GHC.Tc.Errors.Types
import GHC.Tc.Gen.Match
import GHC.Tc.Gen.Head( tcCheckId )
import GHC.Tc.Utils.Concrete ( hasFixedRuntimeRep_syntactic )
import GHC.Tc.Utils.TcType
import GHC.Tc.Utils.TcMType
import GHC.Tc.Gen.Bind
import GHC.Tc.Gen.Pat
import GHC.Tc.Utils.Unify
import GHC.Tc.Utils.Monad
import GHC.Tc.Utils.Env
import GHC.Tc.Types.Origin
import GHC.Tc.Types.Evidence
import GHC.Core.Multiplicity
import GHC.Core.Coercion
import GHC.Types.Id( mkLocalId )
import GHC.Tc.Utils.Instantiate
import GHC.Builtin.Types
import GHC.Types.Var.Set
import GHC.Builtin.Types.Prim
import GHC.Types.Basic( Arity )
import GHC.Types.Error
import GHC.Types.SrcLoc
import GHC.Utils.Outputable
import GHC.Utils.Panic
import GHC.Utils.Misc

import Control.Monad

{-
Note [Arrow overview]
~~~~~~~~~~~~~~~~~~~~~
Here's a summary of arrows and how they typecheck.  First, here's
a cut-down syntax:

  expr ::= ....
        |  proc pat cmd

  cmd ::= cmd exp                    -- Arrow application
       |  \pat -> cmd                -- Arrow abstraction
       |  (| exp cmd1 ... cmdn |)    -- Arrow form, n>=0
       |  ... -- If, case in the usual way

  cmd_type ::= carg_type --> type

  carg_type ::= ()
             |  (type, carg_type)

Note that
 * The 'exp' in an arrow form can mention only
   "arrow-local" variables

 * An "arrow-local" variable is bound by an enclosing
   cmd binding form (eg arrow abstraction)

 * A cmd_type is here written with a funny arrow "-->",
   The bit on the left is a carg_type (command argument type)
   which itself is a nested tuple, finishing with ()

 * The arrow-tail operator (e1 -< e2) means
       (| e1 <<< arr snd |) e2


************************************************************************
*                                                                      *
                Proc
*                                                                      *
************************************************************************
-}

tcProc :: LPat GhcRn -> LHsCmdTop GhcRn         -- proc pat -> expr
       -> ExpRhoType                            -- Expected type of whole proc expression
       -> TcM (LPat GhcTc, LHsCmdTop GhcTc, TcCoercion)

tcProc :: LPat GhcRn
-> LHsCmdTop GhcRn
-> ExpRhoType
-> TcM (LPat GhcTc, LHsCmdTop GhcTc, TcCoercion)
tcProc LPat GhcRn
pat cmd :: LHsCmdTop GhcRn
cmd@(L EpAnnCO
loc (HsCmdTop XCmdTop GhcRn
names LHsCmd GhcRn
_)) ExpRhoType
exp_ty
  = do  { exp_ty <- ExpRhoType -> TcM TcType
expTypeToType ExpRhoType
exp_ty  -- no higher-rank stuff with arrows
        ; (co, (exp_ty1, res_ty)) <- matchExpectedAppTy exp_ty
        ; (co1, (arr_ty, arg_ty)) <- matchExpectedAppTy exp_ty1
        -- start with the names as they are used to desugar the proc itself
        -- See #17423
        ; names' <- setSrcSpanA loc $
            mapM (tcSyntaxName ProcOrigin arr_ty) names
        ; let cmd_env = CmdEnv { cmd_arr :: TcType
cmd_arr = TcType
arr_ty }
        ; (pat', cmd') <- newArrowScope
                          $ tcCheckPat (ArrowMatchCtxt ProcExpr) pat (unrestricted arg_ty)
                          $ tcCmdTop cmd_env names' cmd (unitTy, res_ty)
        ; let res_co = TcCoercion
co TcCoercion -> TcCoercion -> TcCoercion
`mkTransCo` TcCoercion -> TcCoercion -> TcCoercion
mkAppCo TcCoercion
co1 (TcType -> TcCoercion
mkNomReflCo TcType
res_ty)
        ; return (pat', cmd', res_co) }

{-
************************************************************************
*                                                                      *
                Commands
*                                                                      *
************************************************************************
-}

-- See Note [Arrow overview]
type CmdType    = (CmdArgType, TcTauType)    -- cmd_type
type CmdArgType = TcTauType                  -- carg_type, a nested tuple

data CmdEnv
  = CmdEnv {
        CmdEnv -> TcType
cmd_arr :: TcType -- ^ Arrow type constructor, of kind *->*->*
    }

mkCmdArrTy :: CmdEnv -> TcTauType -> TcTauType -> TcTauType
mkCmdArrTy :: CmdEnv -> TcType -> TcType -> TcType
mkCmdArrTy CmdEnv
env TcType
t1 TcType
t2 = TcType -> [TcType] -> TcType
mkAppTys (CmdEnv -> TcType
cmd_arr CmdEnv
env) [TcType
t1, TcType
t2]

---------------------------------------
tcCmdTop :: CmdEnv
         -> CmdSyntaxTable GhcTc -- ^ Type-checked Arrow class methods (arr, (>>>), ...)
         -> LHsCmdTop GhcRn
         -> CmdType
         -> TcM (LHsCmdTop GhcTc)

tcCmdTop :: CmdEnv
-> [(Name, HsExpr GhcTc)]
-> LHsCmdTop GhcRn
-> (TcType, TcType)
-> TcM (LHsCmdTop GhcTc)
tcCmdTop CmdEnv
env [(Name, HsExpr GhcTc)]
names (L EpAnnCO
loc (HsCmdTop XCmdTop GhcRn
_names LHsCmd GhcRn
cmd)) cmd_ty :: (TcType, TcType)
cmd_ty@(TcType
cmd_stk, TcType
res_ty)
  = EpAnnCO -> TcM (LHsCmdTop GhcTc) -> TcM (LHsCmdTop GhcTc)
forall ann a. EpAnn ann -> TcRn a -> TcRn a
setSrcSpanA EpAnnCO
loc (TcM (LHsCmdTop GhcTc) -> TcM (LHsCmdTop GhcTc))
-> TcM (LHsCmdTop GhcTc) -> TcM (LHsCmdTop GhcTc)
forall a b. (a -> b) -> a -> b
$
    do  { cmd' <- CmdEnv -> LHsCmd GhcRn -> (TcType, TcType) -> TcM (LHsCmd GhcTc)
tcCmd CmdEnv
env LHsCmd GhcRn
cmd (TcType, TcType)
cmd_ty
        ; return (L loc $ HsCmdTop (CmdTopTc cmd_stk res_ty names) cmd') }

----------------------------------------
tcCmd  :: CmdEnv -> LHsCmd GhcRn -> CmdType -> TcM (LHsCmd GhcTc)
        -- The main recursive function
tcCmd :: CmdEnv -> LHsCmd GhcRn -> (TcType, TcType) -> TcM (LHsCmd GhcTc)
tcCmd CmdEnv
env (L EpAnn AnnListItem
loc HsCmd GhcRn
cmd) cmd_ty :: (TcType, TcType)
cmd_ty@(TcType
_, TcType
res_ty)
  = SrcSpan -> TcM (LHsCmd GhcTc) -> TcM (LHsCmd GhcTc)
forall a. SrcSpan -> TcRn a -> TcRn a
setSrcSpan (EpAnn AnnListItem -> SrcSpan
forall a. HasLoc a => a -> SrcSpan
locA EpAnn AnnListItem
loc) (TcM (LHsCmd GhcTc) -> TcM (LHsCmd GhcTc))
-> TcM (LHsCmd GhcTc) -> TcM (LHsCmd GhcTc)
forall a b. (a -> b) -> a -> b
$ do
        { cmd' <- CmdEnv -> HsCmd GhcRn -> (TcType, TcType) -> TcM (HsCmd GhcTc)
tc_cmd CmdEnv
env HsCmd GhcRn
cmd (TcType, TcType)
cmd_ty
        ; hasFixedRuntimeRep_syntactic (FRRArrow $ ArrowCmdResTy cmd) res_ty
        ; return (L loc cmd') }

tc_cmd :: CmdEnv -> HsCmd GhcRn  -> CmdType -> TcM (HsCmd GhcTc)
tc_cmd :: CmdEnv -> HsCmd GhcRn -> (TcType, TcType) -> TcM (HsCmd GhcTc)
tc_cmd CmdEnv
env (HsCmdPar XCmdPar GhcRn
x LHsCmd GhcRn
cmd) (TcType, TcType)
res_ty
  = do  { cmd' <- CmdEnv -> LHsCmd GhcRn -> (TcType, TcType) -> TcM (LHsCmd GhcTc)
tcCmd CmdEnv
env LHsCmd GhcRn
cmd (TcType, TcType)
res_ty
        ; return (HsCmdPar x cmd') }

tc_cmd CmdEnv
env (HsCmdLet XCmdLet GhcRn
x HsLocalBinds GhcRn
binds (L EpAnn AnnListItem
body_loc HsCmd GhcRn
body)) (TcType, TcType)
res_ty
  = do  { (binds', _, body') <- HsLocalBinds GhcRn
-> TcM (HsCmd GhcTc)
-> TcM (HsLocalBinds GhcTc, HsWrapper, HsCmd GhcTc)
forall thing.
HsLocalBinds GhcRn
-> TcM thing -> TcM (HsLocalBinds GhcTc, HsWrapper, thing)
tcLocalBinds HsLocalBinds GhcRn
binds         (TcM (HsCmd GhcTc)
 -> TcM (HsLocalBinds GhcTc, HsWrapper, HsCmd GhcTc))
-> TcM (HsCmd GhcTc)
-> TcM (HsLocalBinds GhcTc, HsWrapper, HsCmd GhcTc)
forall a b. (a -> b) -> a -> b
$
                                SrcSpan -> TcM (HsCmd GhcTc) -> TcM (HsCmd GhcTc)
forall a. SrcSpan -> TcRn a -> TcRn a
setSrcSpan (EpAnn AnnListItem -> SrcSpan
forall a. HasLoc a => a -> SrcSpan
locA EpAnn AnnListItem
body_loc) (TcM (HsCmd GhcTc) -> TcM (HsCmd GhcTc))
-> TcM (HsCmd GhcTc) -> TcM (HsCmd GhcTc)
forall a b. (a -> b) -> a -> b
$
                                CmdEnv -> HsCmd GhcRn -> (TcType, TcType) -> TcM (HsCmd GhcTc)
tc_cmd CmdEnv
env HsCmd GhcRn
body (TcType, TcType)
res_ty
        ; return (HsCmdLet x binds' (L body_loc body')) }

tc_cmd CmdEnv
env in_cmd :: HsCmd GhcRn
in_cmd@(HsCmdCase XCmdCase GhcRn
x LHsExpr GhcRn
scrut MatchGroup GhcRn (LHsCmd GhcRn)
matches) (TcType
stk, TcType
res_ty)
  = SDoc -> TcM (HsCmd GhcTc) -> TcM (HsCmd GhcTc)
forall a. SDoc -> TcM a -> TcM a
addErrCtxt (HsCmd GhcRn -> SDoc
cmdCtxt HsCmd GhcRn
in_cmd) (TcM (HsCmd GhcTc) -> TcM (HsCmd GhcTc))
-> TcM (HsCmd GhcTc) -> TcM (HsCmd GhcTc)
forall a b. (a -> b) -> a -> b
$ do
    do { (scrut', scrut_ty) <- LHsExpr GhcRn -> TcM (LHsExpr GhcTc, TcType)
tcInferRho LHsExpr GhcRn
scrut
       ; hasFixedRuntimeRep_syntactic (FRRArrow $ ArrowCmdCase) scrut_ty
       ; (mult_co_wrap, matches') <- tcCmdMatches env scrut_ty matches (stk, res_ty)
       ; return (HsCmdCase x (mkLHsWrap mult_co_wrap scrut') matches') }

tc_cmd CmdEnv
env (HsCmdIf XCmdIf GhcRn
x SyntaxExpr GhcRn
SyntaxExprRn
NoSyntaxExprRn LHsExpr GhcRn
pred LHsCmd GhcRn
b1 LHsCmd GhcRn
b2) (TcType, TcType)
res_ty    -- Ordinary 'if'
  = do  { pred' <- LHsExpr GhcRn -> TcType -> TcM (LHsExpr GhcTc)
tcCheckMonoExpr LHsExpr GhcRn
pred TcType
boolTy
        ; b1'   <- tcCmd env b1 res_ty
        ; b2'   <- tcCmd env b2 res_ty
        ; return (HsCmdIf x NoSyntaxExprTc pred' b1' b2')
    }

tc_cmd CmdEnv
env (HsCmdIf XCmdIf GhcRn
x fun :: SyntaxExpr GhcRn
fun@(SyntaxExprRn {}) LHsExpr GhcRn
pred LHsCmd GhcRn
b1 LHsCmd GhcRn
b2) (TcType, TcType)
res_ty -- Rebindable syntax for if
  = do  { pred_ty <- TcM TcType
newOpenFlexiTyVarTy
        -- For arrows, need ifThenElse :: forall r. T -> r -> r -> r
        -- because we're going to apply it to the environment, not
        -- the return value.
        ; skol_info <- mkSkolemInfo ArrowReboundIfSkol
        ; (_, [r_tv]) <- tcInstSkolTyVars skol_info [alphaTyVar]
        ; let r_ty = Id -> TcType
mkTyVarTy Id
r_tv
        ; checkTc (not (r_tv `elemVarSet` tyCoVarsOfType pred_ty))
                  TcRnArrowIfThenElsePredDependsOnResultTy
        ; (pred', fun') <- tcSyntaxOp IfThenElseOrigin fun
                              (map synKnownType [pred_ty, r_ty, r_ty])
                              (mkCheckExpType r_ty) $ \ [TcType]
_ [TcType]
_ ->
                           LHsExpr GhcRn -> TcType -> TcM (LHsExpr GhcTc)
tcCheckMonoExpr LHsExpr GhcRn
pred TcType
pred_ty

        ; b1'   <- tcCmd env b1 res_ty
        ; b2'   <- tcCmd env b2 res_ty
        ; return (HsCmdIf x fun' pred' b1' b2')
    }

-------------------------------------------
--              Arrow application
--          (f -< a)   or   (f -<< a)
--
--   D   |- fun :: a t1 t2
--   D,G |- arg :: t1
--  ------------------------
--   D;G |-a  fun -< arg :: stk --> t2
--
--   D,G |- fun :: a t1 t2
--   D,G |- arg :: t1
--  ------------------------
--   D;G |-a  fun -<< arg :: stk --> t2
--
-- (plus -<< requires ArrowApply)

tc_cmd CmdEnv
env cmd :: HsCmd GhcRn
cmd@(HsCmdArrApp XCmdArrApp GhcRn
_ LHsExpr GhcRn
fun LHsExpr GhcRn
arg HsArrAppType
ho_app Bool
lr) (TcType
_, TcType
res_ty)
  = SDoc -> TcM (HsCmd GhcTc) -> TcM (HsCmd GhcTc)
forall a. SDoc -> TcM a -> TcM a
addErrCtxt (HsCmd GhcRn -> SDoc
cmdCtxt HsCmd GhcRn
cmd)    (TcM (HsCmd GhcTc) -> TcM (HsCmd GhcTc))
-> TcM (HsCmd GhcTc) -> TcM (HsCmd GhcTc)
forall a b. (a -> b) -> a -> b
$
    do  { arg_ty <- TcM TcType
newOpenFlexiTyVarTy
        ; let fun_ty = CmdEnv -> TcType -> TcType -> TcType
mkCmdArrTy CmdEnv
env TcType
arg_ty TcType
res_ty
        ; fun' <- select_arrow_scope (tcCheckMonoExpr fun fun_ty)

        ; arg' <- tcCheckMonoExpr arg arg_ty

        ; hasFixedRuntimeRep_syntactic
            (FRRArrow $ ArrowCmdArrApp (unLoc fun) (unLoc arg) ho_app)
            fun_ty

        ; return (HsCmdArrApp fun_ty fun' arg' ho_app lr) }
  where
       -- Before type-checking f, use the environment of the enclosing
       -- proc for the (-<) case.
       -- Local bindings, inside the enclosing proc, are not in scope
       -- inside f.  In the higher-order case (-<<), they are.
       -- See Note [Escaping the arrow scope] in GHC.Tc.Types
    select_arrow_scope :: IOEnv
  (Env TcGblEnv TcLclEnv)
  (GenLocated (EpAnn AnnListItem) (HsExpr GhcTc))
-> IOEnv
     (Env TcGblEnv TcLclEnv)
     (GenLocated (EpAnn AnnListItem) (HsExpr GhcTc))
select_arrow_scope IOEnv
  (Env TcGblEnv TcLclEnv)
  (GenLocated (EpAnn AnnListItem) (HsExpr GhcTc))
tc = case HsArrAppType
ho_app of
        HsArrAppType
HsHigherOrderApp -> IOEnv
  (Env TcGblEnv TcLclEnv)
  (GenLocated (EpAnn AnnListItem) (HsExpr GhcTc))
tc
        HsArrAppType
HsFirstOrderApp  -> IOEnv
  (Env TcGblEnv TcLclEnv)
  (GenLocated (EpAnn AnnListItem) (HsExpr GhcTc))
-> IOEnv
     (Env TcGblEnv TcLclEnv)
     (GenLocated (EpAnn AnnListItem) (HsExpr GhcTc))
forall a. TcM a -> TcM a
escapeArrowScope IOEnv
  (Env TcGblEnv TcLclEnv)
  (GenLocated (EpAnn AnnListItem) (HsExpr GhcTc))
tc

-------------------------------------------
--              Command application
--
-- D,G |-  exp : t
-- D;G |-a cmd : (t,stk) --> res
-- -----------------------------
-- D;G |-a cmd exp : stk --> res

tc_cmd CmdEnv
env cmd :: HsCmd GhcRn
cmd@(HsCmdApp XCmdApp GhcRn
x LHsCmd GhcRn
fun LHsExpr GhcRn
arg) (TcType
cmd_stk, TcType
res_ty)
  = SDoc -> TcM (HsCmd GhcTc) -> TcM (HsCmd GhcTc)
forall a. SDoc -> TcM a -> TcM a
addErrCtxt (HsCmd GhcRn -> SDoc
cmdCtxt HsCmd GhcRn
cmd)    (TcM (HsCmd GhcTc) -> TcM (HsCmd GhcTc))
-> TcM (HsCmd GhcTc) -> TcM (HsCmd GhcTc)
forall a b. (a -> b) -> a -> b
$
    do  { arg_ty <- TcM TcType
newOpenFlexiTyVarTy
        ; fun'   <- tcCmd env fun (mkPairTy arg_ty cmd_stk, res_ty)
        ; arg'   <- tcCheckMonoExpr arg arg_ty
        ; hasFixedRuntimeRep_syntactic
            (FRRArrow $ ArrowCmdApp (unLoc fun) (unLoc arg))
            arg_ty
        ; return (HsCmdApp x fun' arg') }

-------------------------------------------
--              Lambda
--
-- D;G,x:t |-a cmd : stk --> res
-- ------------------------------
-- D;G |-a (\x.cmd) : (t,stk) --> res

tc_cmd CmdEnv
env cmd :: HsCmd GhcRn
cmd@(HsCmdLam XCmdLamCase GhcRn
x HsLamVariant
lam_variant MatchGroup GhcRn (LHsCmd GhcRn)
match) (TcType, TcType)
cmd_ty
  = (case HsLamVariant
lam_variant of   -- Add context only for \case and \cases
        HsLamVariant
LamSingle -> TcM (HsCmd GhcTc) -> TcM (HsCmd GhcTc)
forall a. a -> a
id    -- Avoids clutter in the vanilla-lambda form
        HsLamVariant
_         -> SDoc -> TcM (HsCmd GhcTc) -> TcM (HsCmd GhcTc)
forall a. SDoc -> TcM a -> TcM a
addErrCtxt (HsCmd GhcRn -> SDoc
cmdCtxt HsCmd GhcRn
cmd)) (TcM (HsCmd GhcTc) -> TcM (HsCmd GhcTc))
-> TcM (HsCmd GhcTc) -> TcM (HsCmd GhcTc)
forall a b. (a -> b) -> a -> b
$
    do { let match_ctxt :: HsArrowMatchContext
match_ctxt = HsLamVariant -> HsArrowMatchContext
ArrowLamAlt HsLamVariant
lam_variant
       ; arity <- MatchGroup GhcRn (GenLocated (EpAnn AnnListItem) (HsCmd GhcRn))
-> TcM Arity
forall (body :: * -> *).
AnnoBody body =>
MatchGroup GhcRn (LocatedA (body GhcRn)) -> TcM Arity
checkArgCounts MatchGroup GhcRn (LHsCmd GhcRn)
MatchGroup GhcRn (GenLocated (EpAnn AnnListItem) (HsCmd GhcRn))
match
       ; (wrap, match') <- tcCmdMatchLambda env match_ctxt arity match cmd_ty
       ; return (mkHsCmdWrap wrap (HsCmdLam x lam_variant match')) }

-------------------------------------------
--              Do notation

tc_cmd CmdEnv
env (HsCmdDo XCmdDo GhcRn
_ (L SrcSpanAnnL
l [GenLocated
   (EpAnn AnnListItem)
   (StmtLR
      GhcRn GhcRn (GenLocated (EpAnn AnnListItem) (HsCmd GhcRn)))]
stmts) ) (TcType
cmd_stk, TcType
res_ty)
  = do  { co <- Maybe TypedThing -> TcType -> TcType -> TcM TcCoercion
unifyType Maybe TypedThing
forall a. Maybe a
Nothing TcType
unitTy TcType
cmd_stk  -- Expecting empty argument stack
        ; stmts' <- tcStmts ArrowExpr (tcArrDoStmt env) stmts res_ty
        ; return (mkHsCmdWrap (mkWpCastN co) (HsCmdDo res_ty (L l stmts') )) }


-----------------------------------------------------------------
--      Arrow ``forms''       (| e c1 .. cn |)
--
--      D; G |-a1 c1 : stk1 --> r1
--      ...
--      D; G |-an cn : stkn --> rn
--      D |-  e :: forall e. a1 (e, stk1) t1
--                                ...
--                        -> an (e, stkn) tn
--                        -> a  (e, stk) t
--      e \not\in (stk, stk1, ..., stkm, t, t1, ..., tn)
--      ----------------------------------------------
--      D; G |-a  (| e c1 ... cn |)  :  stk --> t

tc_cmd CmdEnv
env cmd :: HsCmd GhcRn
cmd@(HsCmdArrForm XCmdArrForm GhcRn
fixity LHsExpr GhcRn
expr LexicalFixity
f [LHsCmdTop GhcRn]
cmd_args) (TcType
cmd_stk, TcType
res_ty)
  = SDoc -> TcM (HsCmd GhcTc) -> TcM (HsCmd GhcTc)
forall a. SDoc -> TcM a -> TcM a
addErrCtxt (HsCmd GhcRn -> SDoc
cmdCtxt HsCmd GhcRn
cmd)
    do  { (cmd_args', cmd_tys) <- (GenLocated EpAnnCO (HsCmdTop GhcRn)
 -> IOEnv
      (Env TcGblEnv TcLclEnv)
      (GenLocated EpAnnCO (HsCmdTop GhcTc), TcType))
-> [GenLocated EpAnnCO (HsCmdTop GhcRn)]
-> IOEnv
     (Env TcGblEnv TcLclEnv)
     ([GenLocated EpAnnCO (HsCmdTop GhcTc)], [TcType])
forall (m :: * -> *) a b c.
Applicative m =>
(a -> m (b, c)) -> [a] -> m ([b], [c])
mapAndUnzipM LHsCmdTop GhcRn -> TcM (LHsCmdTop GhcTc, TcType)
GenLocated EpAnnCO (HsCmdTop GhcRn)
-> IOEnv
     (Env TcGblEnv TcLclEnv)
     (GenLocated EpAnnCO (HsCmdTop GhcTc), TcType)
tc_cmd_arg [LHsCmdTop GhcRn]
[GenLocated EpAnnCO (HsCmdTop GhcRn)]
cmd_args
                              -- We use alphaTyVar for 'w'
        ; let e_ty = Id -> TcType -> TcType
mkInfForAllTy Id
alphaTyVar (TcType -> TcType) -> TcType -> TcType
forall a b. (a -> b) -> a -> b
$
                     [TcType] -> TcType -> TcType
mkVisFunTysMany [TcType]
cmd_tys (TcType -> TcType) -> TcType -> TcType
forall a b. (a -> b) -> a -> b
$
                     CmdEnv -> TcType -> TcType -> TcType
mkCmdArrTy CmdEnv
env (TcType -> TcType -> TcType
mkPairTy TcType
alphaTy TcType
cmd_stk) TcType
res_ty
        ; expr' <- tcCheckPolyExpr expr e_ty
        ; return (HsCmdArrForm fixity expr' f cmd_args') }

  where
    tc_cmd_arg :: LHsCmdTop GhcRn -> TcM (LHsCmdTop GhcTc, TcType)
    tc_cmd_arg :: LHsCmdTop GhcRn -> TcM (LHsCmdTop GhcTc, TcType)
tc_cmd_arg cmd :: LHsCmdTop GhcRn
cmd@(L EpAnnCO
loc (HsCmdTop XCmdTop GhcRn
names LHsCmd GhcRn
_))
       = do { arr_ty <- TcType -> TcM TcType
newFlexiTyVarTy TcType
arrowTyConKind
            ; stk_ty <- newFlexiTyVarTy liftedTypeKind
            ; res_ty <- newFlexiTyVarTy liftedTypeKind
            ; names' <- setSrcSpanA loc $
                mapM (tcSyntaxName ArrowCmdOrigin arr_ty) names
            ; let env' = CmdEnv
env { cmd_arr = arr_ty }
            ; cmd' <- tcCmdTop env' names' cmd (stk_ty, res_ty)
            ; return (cmd',  mkCmdArrTy env' (mkPairTy alphaTy stk_ty) res_ty) }

-- | Typechecking for case command alternatives. Used for 'HsCmdCase'.
tcCmdMatches :: CmdEnv
             -> TcTypeFRR -- ^ Type of the scrutinee.
             -> MatchGroup GhcRn (LHsCmd GhcRn)  -- ^ case alternatives
             -> CmdType
             -> TcM (HsWrapper, MatchGroup GhcTc (LHsCmd GhcTc))
tcCmdMatches :: CmdEnv
-> TcType
-> MatchGroup GhcRn (LHsCmd GhcRn)
-> (TcType, TcType)
-> TcM (HsWrapper, MatchGroup GhcTc (LHsCmd GhcTc))
tcCmdMatches CmdEnv
env TcType
scrut_ty MatchGroup GhcRn (LHsCmd GhcRn)
matches (TcType
stk, TcType
res_ty)
  = TcMatchAltChecker HsCmd
-> Scaled TcType
-> MatchGroup GhcRn (GenLocated (EpAnn AnnListItem) (HsCmd GhcRn))
-> ExpRhoType
-> IOEnv
     (Env TcGblEnv TcLclEnv)
     (HsWrapper,
      MatchGroup GhcTc (GenLocated (EpAnn AnnListItem) (HsCmd GhcTc)))
forall (body :: * -> *).
(AnnoBody body, Outputable (body GhcTc)) =>
TcMatchAltChecker body
-> Scaled TcType
-> MatchGroup GhcRn (LocatedA (body GhcRn))
-> ExpRhoType
-> TcM (HsWrapper, MatchGroup GhcTc (LocatedA (body GhcTc)))
tcCaseMatches TcMatchAltChecker HsCmd
tc_body (TcType -> Scaled TcType
forall a. a -> Scaled a
unrestricted TcType
scrut_ty) MatchGroup GhcRn (LHsCmd GhcRn)
MatchGroup GhcRn (GenLocated (EpAnn AnnListItem) (HsCmd GhcRn))
matches (TcType -> ExpRhoType
mkCheckExpType TcType
res_ty)
  where
    tc_body :: TcMatchAltChecker HsCmd
tc_body GenLocated (EpAnn AnnListItem) (HsCmd GhcRn)
body ExpRhoType
res_ty' = do { res_ty' <- ExpRhoType -> TcM TcType
expTypeToType ExpRhoType
res_ty'
                              ; tcCmd env body (stk, res_ty') }

-- | Typechecking for 'HsCmdLam' and 'HsCmdLamCase'.
tcCmdMatchLambda :: CmdEnv
                 -> HsArrowMatchContext
                 -> Arity
                 -> MatchGroup GhcRn (LHsCmd GhcRn)
                 -> CmdType
                 -> TcM (HsWrapper, MatchGroup GhcTc (LHsCmd GhcTc))
tcCmdMatchLambda :: CmdEnv
-> HsArrowMatchContext
-> Arity
-> MatchGroup GhcRn (LHsCmd GhcRn)
-> (TcType, TcType)
-> TcM (HsWrapper, MatchGroup GhcTc (LHsCmd GhcTc))
tcCmdMatchLambda CmdEnv
env HsArrowMatchContext
ctxt Arity
arity
                 mg :: MatchGroup GhcRn (LHsCmd GhcRn)
mg@MG { mg_alts :: forall p body. MatchGroup p body -> XRec p [LMatch p body]
mg_alts = L SrcSpanAnnL
l [GenLocated
   (EpAnn AnnListItem)
   (Match GhcRn (GenLocated (EpAnn AnnListItem) (HsCmd GhcRn)))]
matches, mg_ext :: forall p body. MatchGroup p body -> XMG p body
mg_ext = XMG GhcRn (LHsCmd GhcRn)
origin }
                 (TcType
cmd_stk, TcType
res_ty)
  = do { (co, arg_tys, cmd_stk') <- Arity -> TcType -> TcM (TcCoercion, [TcType], TcType)
matchExpectedCmdArgs Arity
arity TcType
cmd_stk

       ; let check_arg_tys = (TcType -> Scaled ExpRhoType) -> [TcType] -> [Scaled ExpRhoType]
forall a b. (a -> b) -> [a] -> [b]
map (ExpRhoType -> Scaled ExpRhoType
forall a. a -> Scaled a
unrestricted (ExpRhoType -> Scaled ExpRhoType)
-> (TcType -> ExpRhoType) -> TcType -> Scaled ExpRhoType
forall b c a. (b -> c) -> (a -> b) -> a -> c
. TcType -> ExpRhoType
mkCheckExpType) [TcType]
arg_tys
       ; matches' <- forM matches $
           addErrCtxt . pprMatchInCtxt . unLoc <*> tc_match check_arg_tys cmd_stk'

       ; let arg_tys' = (TcType -> Scaled TcType) -> [TcType] -> [Scaled TcType]
forall a b. (a -> b) -> [a] -> [b]
map TcType -> Scaled TcType
forall a. a -> Scaled a
unrestricted [TcType]
arg_tys
             mg' = MatchGroup GhcRn (LHsCmd GhcRn)
mg { mg_alts = L l matches'
                      , mg_ext = MatchGroupTc arg_tys' res_ty origin }

       ; return (mkWpCastN co, mg') }
  where
    -- Check the patterns, and the GRHSs inside
    tc_match :: [Scaled ExpRhoType]
-> TcType
-> GenLocated
     (EpAnn AnnListItem)
     (Match GhcRn (GenLocated (EpAnn AnnListItem) (HsCmd GhcRn)))
-> IOEnv
     (Env TcGblEnv TcLclEnv)
     (GenLocated
        (EpAnn AnnListItem)
        (Match GhcTc (GenLocated (EpAnn AnnListItem) (HsCmd GhcTc))))
tc_match [Scaled ExpRhoType]
arg_tys TcType
cmd_stk' (L EpAnn AnnListItem
mtch_loc (Match { m_pats :: forall p body. Match p body -> XRec p [LPat p]
m_pats = L EpaLocation
l [GenLocated (EpAnn AnnListItem) (Pat GhcRn)]
pats, m_grhss :: forall p body. Match p body -> GRHSs p body
m_grhss = GRHSs GhcRn (GenLocated (EpAnn AnnListItem) (HsCmd GhcRn))
grhss }))
      = do { (pats', grhss') <- EpAnn AnnListItem
-> TcRn
     ([LPat GhcTc],
      GRHSs GhcTc (GenLocated (EpAnn AnnListItem) (HsCmd GhcTc)))
-> TcRn
     ([LPat GhcTc],
      GRHSs GhcTc (GenLocated (EpAnn AnnListItem) (HsCmd GhcTc)))
forall ann a. EpAnn ann -> TcRn a -> TcRn a
setSrcSpanA EpAnn AnnListItem
mtch_loc           (TcRn
   ([LPat GhcTc],
    GRHSs GhcTc (GenLocated (EpAnn AnnListItem) (HsCmd GhcTc)))
 -> TcRn
      ([LPat GhcTc],
       GRHSs GhcTc (GenLocated (EpAnn AnnListItem) (HsCmd GhcTc))))
-> TcRn
     ([LPat GhcTc],
      GRHSs GhcTc (GenLocated (EpAnn AnnListItem) (HsCmd GhcTc)))
-> TcRn
     ([LPat GhcTc],
      GRHSs GhcTc (GenLocated (EpAnn AnnListItem) (HsCmd GhcTc)))
forall a b. (a -> b) -> a -> b
$
                                HsMatchContextRn
-> [LPat GhcRn]
-> [ExpPatType]
-> TcM (GRHSs GhcTc (GenLocated (EpAnn AnnListItem) (HsCmd GhcTc)))
-> TcRn
     ([LPat GhcTc],
      GRHSs GhcTc (GenLocated (EpAnn AnnListItem) (HsCmd GhcTc)))
forall a.
HsMatchContextRn
-> [LPat GhcRn] -> [ExpPatType] -> TcM a -> TcM ([LPat GhcTc], a)
tcMatchPats HsMatchContextRn
HsMatchContext (GenLocated SrcSpanAnnN Name)
match_ctxt [LPat GhcRn]
[GenLocated (EpAnn AnnListItem) (Pat GhcRn)]
pats ((Scaled ExpRhoType -> ExpPatType)
-> [Scaled ExpRhoType] -> [ExpPatType]
forall a b. (a -> b) -> [a] -> [b]
map Scaled ExpRhoType -> ExpPatType
ExpFunPatTy [Scaled ExpRhoType]
arg_tys) (TcM (GRHSs GhcTc (GenLocated (EpAnn AnnListItem) (HsCmd GhcTc)))
 -> TcRn
      ([LPat GhcTc],
       GRHSs GhcTc (GenLocated (EpAnn AnnListItem) (HsCmd GhcTc))))
-> TcM (GRHSs GhcTc (GenLocated (EpAnn AnnListItem) (HsCmd GhcTc)))
-> TcRn
     ([LPat GhcTc],
      GRHSs GhcTc (GenLocated (EpAnn AnnListItem) (HsCmd GhcTc)))
forall a b. (a -> b) -> a -> b
$
                                GRHSs GhcRn (GenLocated (EpAnn AnnListItem) (HsCmd GhcRn))
-> TcType
-> ExpRhoType
-> TcM (GRHSs GhcTc (GenLocated (EpAnn AnnListItem) (HsCmd GhcTc)))
tc_grhss GRHSs GhcRn (GenLocated (EpAnn AnnListItem) (HsCmd GhcRn))
grhss TcType
cmd_stk' (TcType -> ExpRhoType
mkCheckExpType TcType
res_ty)

           ; return $ L mtch_loc (Match { m_ext = noExtField
                                        , m_ctxt = match_ctxt
                                        , m_pats = L l pats'
                                        , m_grhss = grhss' }) }

    match_ctxt :: HsMatchContext (GenLocated SrcSpanAnnN Name)
match_ctxt = HsArrowMatchContext -> HsMatchContext (GenLocated SrcSpanAnnN Name)
forall fn. HsArrowMatchContext -> HsMatchContext fn
ArrowMatchCtxt HsArrowMatchContext
ctxt
    pg_ctxt :: HsStmtContext (GenLocated SrcSpanAnnN Name)
pg_ctxt    = HsMatchContext (GenLocated SrcSpanAnnN Name)
-> HsStmtContext (GenLocated SrcSpanAnnN Name)
forall fn. HsMatchContext fn -> HsStmtContext fn
PatGuard HsMatchContext (GenLocated SrcSpanAnnN Name)
match_ctxt

    tc_grhss :: GRHSs GhcRn (GenLocated (EpAnn AnnListItem) (HsCmd GhcRn))
-> TcType
-> ExpRhoType
-> TcM (GRHSs GhcTc (GenLocated (EpAnn AnnListItem) (HsCmd GhcTc)))
tc_grhss (GRHSs XCGRHSs GhcRn (GenLocated (EpAnn AnnListItem) (HsCmd GhcRn))
x [LGRHS GhcRn (GenLocated (EpAnn AnnListItem) (HsCmd GhcRn))]
grhss HsLocalBinds GhcRn
binds) TcType
stk_ty ExpRhoType
res_ty
        = do { (binds', _, grhss') <- HsLocalBinds GhcRn
-> TcM
     [GenLocated
        EpAnnCO
        (GRHS GhcTc (GenLocated (EpAnn AnnListItem) (HsCmd GhcTc)))]
-> TcM
     (HsLocalBinds GhcTc, HsWrapper,
      [GenLocated
         EpAnnCO
         (GRHS GhcTc (GenLocated (EpAnn AnnListItem) (HsCmd GhcTc)))])
forall thing.
HsLocalBinds GhcRn
-> TcM thing -> TcM (HsLocalBinds GhcTc, HsWrapper, thing)
tcLocalBinds HsLocalBinds GhcRn
binds (TcM
   [GenLocated
      EpAnnCO
      (GRHS GhcTc (GenLocated (EpAnn AnnListItem) (HsCmd GhcTc)))]
 -> TcM
      (HsLocalBinds GhcTc, HsWrapper,
       [GenLocated
          EpAnnCO
          (GRHS GhcTc (GenLocated (EpAnn AnnListItem) (HsCmd GhcTc)))]))
-> TcM
     [GenLocated
        EpAnnCO
        (GRHS GhcTc (GenLocated (EpAnn AnnListItem) (HsCmd GhcTc)))]
-> TcM
     (HsLocalBinds GhcTc, HsWrapper,
      [GenLocated
         EpAnnCO
         (GRHS GhcTc (GenLocated (EpAnn AnnListItem) (HsCmd GhcTc)))])
forall a b. (a -> b) -> a -> b
$
                                      (GenLocated
   EpAnnCO (GRHS GhcRn (GenLocated (EpAnn AnnListItem) (HsCmd GhcRn)))
 -> IOEnv
      (Env TcGblEnv TcLclEnv)
      (GenLocated
         EpAnnCO
         (GRHS GhcTc (GenLocated (EpAnn AnnListItem) (HsCmd GhcTc)))))
-> [GenLocated
      EpAnnCO
      (GRHS GhcRn (GenLocated (EpAnn AnnListItem) (HsCmd GhcRn)))]
-> TcM
     [GenLocated
        EpAnnCO
        (GRHS GhcTc (GenLocated (EpAnn AnnListItem) (HsCmd GhcTc)))]
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
forall (m :: * -> *) a b. Monad m => (a -> m b) -> [a] -> m [b]
mapM ((GRHS GhcRn (GenLocated (EpAnn AnnListItem) (HsCmd GhcRn))
 -> TcM (GRHS GhcTc (GenLocated (EpAnn AnnListItem) (HsCmd GhcTc))))
-> GenLocated
     EpAnnCO (GRHS GhcRn (GenLocated (EpAnn AnnListItem) (HsCmd GhcRn)))
-> IOEnv
     (Env TcGblEnv TcLclEnv)
     (GenLocated
        EpAnnCO
        (GRHS GhcTc (GenLocated (EpAnn AnnListItem) (HsCmd GhcTc))))
forall a b ann.
(a -> TcM b)
-> GenLocated (EpAnn ann) a -> TcRn (GenLocated (EpAnn ann) b)
wrapLocMA (TcType
-> ExpRhoType
-> GRHS GhcRn (GenLocated (EpAnn AnnListItem) (HsCmd GhcRn))
-> TcM (GRHS GhcTc (GenLocated (EpAnn AnnListItem) (HsCmd GhcTc)))
tc_grhs TcType
stk_ty ExpRhoType
res_ty)) [LGRHS GhcRn (GenLocated (EpAnn AnnListItem) (HsCmd GhcRn))]
[GenLocated
   EpAnnCO
   (GRHS GhcRn (GenLocated (EpAnn AnnListItem) (HsCmd GhcRn)))]
grhss
             ; return (GRHSs x grhss' binds') }

    tc_grhs :: TcType
-> ExpRhoType
-> GRHS GhcRn (GenLocated (EpAnn AnnListItem) (HsCmd GhcRn))
-> TcM (GRHS GhcTc (GenLocated (EpAnn AnnListItem) (HsCmd GhcTc)))
tc_grhs TcType
stk_ty ExpRhoType
res_ty (GRHS XCGRHS GhcRn (GenLocated (EpAnn AnnListItem) (HsCmd GhcRn))
x [GuardLStmt GhcRn]
guards GenLocated (EpAnn AnnListItem) (HsCmd GhcRn)
body)
        = do { (guards', rhs') <- HsStmtContextRn
-> TcStmtChecker HsExpr ExpRhoType
-> [LStmt GhcRn (GenLocated (EpAnn AnnListItem) (HsExpr GhcRn))]
-> ExpRhoType
-> (ExpRhoType
    -> IOEnv
         (Env TcGblEnv TcLclEnv)
         (GenLocated (EpAnn AnnListItem) (HsCmd GhcTc)))
-> TcM
     ([LStmt GhcTc (GenLocated (EpAnn AnnListItem) (HsExpr GhcTc))],
      GenLocated (EpAnn AnnListItem) (HsCmd GhcTc))
forall (body :: * -> *) rho_type thing.
AnnoBody body =>
HsStmtContextRn
-> TcStmtChecker body rho_type
-> [LStmt GhcRn (LocatedA (body GhcRn))]
-> rho_type
-> (rho_type -> TcM thing)
-> TcM ([LStmt GhcTc (LocatedA (body GhcTc))], thing)
tcStmtsAndThen HsStmtContextRn
HsStmtContext (GenLocated SrcSpanAnnN Name)
pg_ctxt HsStmtContextRn
-> Stmt GhcRn (GenLocated (EpAnn AnnListItem) (HsExpr GhcRn))
-> ExpRhoType
-> (ExpRhoType -> TcM thing)
-> TcM
     (StmtLR
        GhcTc GhcTc (GenLocated (EpAnn AnnListItem) (HsExpr GhcTc)),
      thing)
TcStmtChecker HsExpr ExpRhoType
tcGuardStmt [GuardLStmt GhcRn]
[LStmt GhcRn (GenLocated (EpAnn AnnListItem) (HsExpr GhcRn))]
guards ExpRhoType
res_ty ((ExpRhoType
  -> IOEnv
       (Env TcGblEnv TcLclEnv)
       (GenLocated (EpAnn AnnListItem) (HsCmd GhcTc)))
 -> TcM
      ([LStmt GhcTc (GenLocated (EpAnn AnnListItem) (HsExpr GhcTc))],
       GenLocated (EpAnn AnnListItem) (HsCmd GhcTc)))
-> (ExpRhoType
    -> IOEnv
         (Env TcGblEnv TcLclEnv)
         (GenLocated (EpAnn AnnListItem) (HsCmd GhcTc)))
-> TcM
     ([LStmt GhcTc (GenLocated (EpAnn AnnListItem) (HsExpr GhcTc))],
      GenLocated (EpAnn AnnListItem) (HsCmd GhcTc))
forall a b. (a -> b) -> a -> b
$
                                  \ ExpRhoType
res_ty -> CmdEnv -> LHsCmd GhcRn -> (TcType, TcType) -> TcM (LHsCmd GhcTc)
tcCmd CmdEnv
env LHsCmd GhcRn
GenLocated (EpAnn AnnListItem) (HsCmd GhcRn)
body
                                                (TcType
stk_ty, ExpRhoType -> TcType
checkingExpType ExpRhoType
res_ty)
             ; return (GRHS x guards' rhs') }

matchExpectedCmdArgs :: Arity -> TcType -> TcM (TcCoercionN, [TcTypeFRR], TcType)
matchExpectedCmdArgs :: Arity -> TcType -> TcM (TcCoercion, [TcType], TcType)
matchExpectedCmdArgs Arity
0 TcType
ty
  = (TcCoercion, [TcType], TcType)
-> TcM (TcCoercion, [TcType], TcType)
forall a. a -> IOEnv (Env TcGblEnv TcLclEnv) a
forall (m :: * -> *) a. Monad m => a -> m a
return (TcType -> TcCoercion
mkNomReflCo TcType
ty, [], TcType
ty)
matchExpectedCmdArgs Arity
n TcType
ty
  = do { (co1, [ty1, ty2]) <- TyCon -> TcType -> TcM (TcCoercion, [TcType])
matchExpectedTyConApp TyCon
pairTyCon TcType
ty
       ; (co2, tys, res_ty) <- matchExpectedCmdArgs (n-1) ty2
       ; return (mkTyConAppCo Nominal pairTyCon [co1, co2], ty1:tys, res_ty) }

{-
************************************************************************
*                                                                      *
                Stmts
*                                                                      *
************************************************************************
-}

--------------------------------
--      Mdo-notation
-- The distinctive features here are
--      (a) RecStmts, and
--      (b) no rebindable syntax

tcArrDoStmt :: CmdEnv -> TcCmdStmtChecker
tcArrDoStmt :: CmdEnv -> TcStmtChecker HsCmd TcType
tcArrDoStmt CmdEnv
env HsStmtContextRn
_ (LastStmt XLastStmt
  GhcRn GhcRn (GenLocated (EpAnn AnnListItem) (HsCmd GhcRn))
x GenLocated (EpAnn AnnListItem) (HsCmd GhcRn)
rhs Maybe Bool
noret SyntaxExpr GhcRn
_) TcType
res_ty TcType -> TcM thing
thing_inside
  = do  { rhs' <- CmdEnv -> LHsCmd GhcRn -> (TcType, TcType) -> TcM (LHsCmd GhcTc)
tcCmd CmdEnv
env LHsCmd GhcRn
GenLocated (EpAnn AnnListItem) (HsCmd GhcRn)
rhs (TcType
unitTy, TcType
res_ty)
        ; thing <- thing_inside (panic "tcArrDoStmt")
        ; return (LastStmt x rhs' noret noSyntaxExpr, thing) }

tcArrDoStmt CmdEnv
env HsStmtContextRn
_ (BodyStmt XBodyStmt
  GhcRn GhcRn (GenLocated (EpAnn AnnListItem) (HsCmd GhcRn))
_ GenLocated (EpAnn AnnListItem) (HsCmd GhcRn)
rhs SyntaxExpr GhcRn
_ SyntaxExpr GhcRn
_) TcType
res_ty TcType -> TcM thing
thing_inside
  = do  { (rhs', elt_ty) <- CmdEnv -> LHsCmd GhcRn -> TcM (LHsCmd GhcTc, TcType)
tc_arr_rhs CmdEnv
env LHsCmd GhcRn
GenLocated (EpAnn AnnListItem) (HsCmd GhcRn)
rhs
        ; thing          <- thing_inside res_ty
        ; return (BodyStmt elt_ty rhs' noSyntaxExpr noSyntaxExpr, thing) }

tcArrDoStmt CmdEnv
env HsStmtContextRn
ctxt (BindStmt XBindStmt
  GhcRn GhcRn (GenLocated (EpAnn AnnListItem) (HsCmd GhcRn))
_ LPat GhcRn
pat GenLocated (EpAnn AnnListItem) (HsCmd GhcRn)
rhs) TcType
res_ty TcType -> TcM thing
thing_inside
  = do  { (rhs', pat_ty) <- CmdEnv -> LHsCmd GhcRn -> TcM (LHsCmd GhcTc, TcType)
tc_arr_rhs CmdEnv
env LHsCmd GhcRn
GenLocated (EpAnn AnnListItem) (HsCmd GhcRn)
rhs
        ; (pat', thing)  <- tcCheckPat (StmtCtxt ctxt) pat (unrestricted pat_ty) $
                            thing_inside res_ty
        ; return (mkTcBindStmt pat' rhs', thing) }

tcArrDoStmt CmdEnv
env HsStmtContextRn
ctxt (RecStmt { recS_stmts :: forall idL idR body.
StmtLR idL idR body -> XRec idR [LStmtLR idL idR body]
recS_stmts = L SrcSpanAnnL
l [GenLocated
   (EpAnn AnnListItem)
   (StmtLR
      GhcRn GhcRn (GenLocated (EpAnn AnnListItem) (HsCmd GhcRn)))]
stmts, recS_later_ids :: forall idL idR body. StmtLR idL idR body -> [IdP idR]
recS_later_ids = [IdP GhcRn]
later_names
                            , recS_rec_ids :: forall idL idR body. StmtLR idL idR body -> [IdP idR]
recS_rec_ids = [IdP GhcRn]
rec_names }) TcType
res_ty TcType -> TcM thing
thing_inside
  = do  { let tup_names :: [IdP GhcRn]
tup_names = [IdP GhcRn]
rec_names [IdP GhcRn] -> [IdP GhcRn] -> [IdP GhcRn]
forall a. [a] -> [a] -> [a]
++ (IdP GhcRn -> Bool) -> [IdP GhcRn] -> [IdP GhcRn]
forall a. (a -> Bool) -> [a] -> [a]
filterOut (IdP GhcRn -> [IdP GhcRn] -> Bool
forall a. Eq a => a -> [a] -> Bool
forall (t :: * -> *) a. (Foldable t, Eq a) => a -> t a -> Bool
`elem` [IdP GhcRn]
rec_names) [IdP GhcRn]
later_names
        ; tup_elt_tys <- Arity -> TcType -> TcM [TcType]
newFlexiTyVarTys ([Name] -> Arity
forall a. [a] -> Arity
forall (t :: * -> *) a. Foldable t => t a -> Arity
length [IdP GhcRn]
[Name]
tup_names) TcType
liftedTypeKind
        ; let tup_ids = (Name -> TcType -> Id) -> [Name] -> [TcType] -> [Id]
forall a b c. (a -> b -> c) -> [a] -> [b] -> [c]
zipWith (\Name
n TcType
p -> HasDebugCallStack => Name -> TcType -> TcType -> Id
Name -> TcType -> TcType -> Id
mkLocalId Name
n TcType
ManyTy TcType
p) [IdP GhcRn]
[Name]
tup_names [TcType]
tup_elt_tys
                        -- Many because it's a recursive definition
        ; tcExtendIdEnv tup_ids $ do
        { (stmts', tup_rets)
                <- tcStmtsAndThen ctxt (tcArrDoStmt env) stmts res_ty   $ \ TcType
_res_ty' ->
                        -- ToDo: res_ty not really right
                   (Name
 -> ExpRhoType -> IOEnv (Env TcGblEnv TcLclEnv) (HsExpr GhcTc))
-> [Name] -> [ExpRhoType] -> TcM [HsExpr GhcTc]
forall (m :: * -> *) a b c.
Applicative m =>
(a -> b -> m c) -> [a] -> [b] -> m [c]
zipWithM Name -> ExpRhoType -> IOEnv (Env TcGblEnv TcLclEnv) (HsExpr GhcTc)
tcCheckId [IdP GhcRn]
[Name]
tup_names ((TcType -> ExpRhoType) -> [TcType] -> [ExpRhoType]
forall a b. (a -> b) -> [a] -> [b]
map TcType -> ExpRhoType
mkCheckExpType [TcType]
tup_elt_tys)

        ; thing <- thing_inside res_ty
                -- NB:  The rec_ids for the recursive things
                --      already scope over this part. This binding may shadow
                --      some of them with polymorphic things with the same Name
                --      (see Note [How RecStmt works] in Language.Haskell.Syntax.Expr)

        ; let rec_ids = [Name] -> [Id] -> [Id]
forall b a. [b] -> [a] -> [a]
takeList [IdP GhcRn]
[Name]
rec_names [Id]
tup_ids
        ; later_ids <- tcLookupLocalIds later_names

        ; let rec_rets = [Name] -> [HsExpr GhcTc] -> [HsExpr GhcTc]
forall b a. [b] -> [a] -> [a]
takeList [IdP GhcRn]
[Name]
rec_names [HsExpr GhcTc]
tup_rets
        ; let ret_table = [Id] -> [HsExpr GhcTc] -> [(Id, HsExpr GhcTc)]
forall a b. [a] -> [b] -> [(a, b)]
zip [Id]
tup_ids [HsExpr GhcTc]
tup_rets
        ; let later_rets = [HsExpr GhcTc
r | Id
i <- [Id]
later_ids, (Id
j, HsExpr GhcTc
r) <- [(Id, HsExpr GhcTc)]
ret_table, Id
i Id -> Id -> Bool
forall a. Eq a => a -> a -> Bool
== Id
j]

        ; let
            stmt :: Stmt GhcTc (LocatedA (HsCmd GhcTc))
            stmt = StmtLR GhcTc GhcTc (GenLocated (EpAnn AnnListItem) (HsCmd GhcTc))
emptyRecStmtId
                                 { recS_stmts = L l stmts'
                                 -- { recS_stmts = _ stmts'
                                 , recS_later_ids = later_ids
                                 , recS_rec_ids = rec_ids
                                 , recS_ext = unitRecStmtTc
                                     { recS_later_rets = later_rets
                                     , recS_rec_rets = rec_rets
                                     , recS_ret_ty = res_ty} }
        ; return (stmt, thing)
        }}

tcArrDoStmt CmdEnv
_ HsStmtContextRn
_ StmtLR GhcRn GhcRn (GenLocated (EpAnn AnnListItem) (HsCmd GhcRn))
stmt TcType
_ TcType -> TcM thing
_
  = String
-> SDoc
-> IOEnv
     (Env TcGblEnv TcLclEnv)
     (StmtLR GhcTc GhcTc (GenLocated (EpAnn AnnListItem) (HsCmd GhcTc)),
      thing)
forall a. HasCallStack => String -> SDoc -> a
pprPanic String
"tcArrDoStmt: unexpected Stmt" (StmtLR GhcRn GhcRn (GenLocated (EpAnn AnnListItem) (HsCmd GhcRn))
-> SDoc
forall a. Outputable a => a -> SDoc
ppr StmtLR GhcRn GhcRn (GenLocated (EpAnn AnnListItem) (HsCmd GhcRn))
stmt)

tc_arr_rhs :: CmdEnv -> LHsCmd GhcRn -> TcM (LHsCmd GhcTc, TcType)
tc_arr_rhs :: CmdEnv -> LHsCmd GhcRn -> TcM (LHsCmd GhcTc, TcType)
tc_arr_rhs CmdEnv
env LHsCmd GhcRn
rhs = do { ty <- TcType -> TcM TcType
newFlexiTyVarTy TcType
liftedTypeKind
                        ; rhs' <- tcCmd env rhs (unitTy, ty)
                        ; return (rhs', ty) }

{-
************************************************************************
*                                                                      *
                Helpers
*                                                                      *
************************************************************************
-}

mkPairTy :: Type -> Type -> Type
mkPairTy :: TcType -> TcType -> TcType
mkPairTy TcType
t1 TcType
t2 = TyCon -> [TcType] -> TcType
mkTyConApp TyCon
pairTyCon [TcType
t1,TcType
t2]

arrowTyConKind :: Kind          --  *->*->*
arrowTyConKind :: TcType
arrowTyConKind = [TcType] -> TcType -> TcType
mkVisFunTysMany [TcType
liftedTypeKind, TcType
liftedTypeKind] TcType
liftedTypeKind

{-
************************************************************************
*                                                                      *
                Errors
*                                                                      *
************************************************************************
-}

cmdCtxt :: HsCmd GhcRn -> SDoc
cmdCtxt :: HsCmd GhcRn -> SDoc
cmdCtxt HsCmd GhcRn
cmd = String -> SDoc
forall doc. IsLine doc => String -> doc
text String
"In the command:" SDoc -> SDoc -> SDoc
forall doc. IsLine doc => doc -> doc -> doc
<+> HsCmd GhcRn -> SDoc
forall a. Outputable a => a -> SDoc
ppr HsCmd GhcRn
cmd