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

-}

{-# LANGUAGE RankNTypes, TupleSections #-}
{-# LANGUAGE TypeFamilies #-}

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

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

import GHC.Prelude

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

import GHC.Hs
import GHC.Tc.Gen.Match
import GHC.Tc.Utils.Zonk( hsLPatType )
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.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.SrcLoc
import GHC.Utils.Outputable
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 LHsCmdTop GhcRn
cmd ExpRhoType
exp_ty
  = TcM (Located (Pat GhcTc), LHsCmdTop GhcTc, TcCoercion)
-> TcM (Located (Pat GhcTc), LHsCmdTop GhcTc, TcCoercion)
forall a. TcM a -> TcM a
newArrowScope (TcM (Located (Pat GhcTc), LHsCmdTop GhcTc, TcCoercion)
 -> TcM (Located (Pat GhcTc), LHsCmdTop GhcTc, TcCoercion))
-> TcM (Located (Pat GhcTc), LHsCmdTop GhcTc, TcCoercion)
-> TcM (Located (Pat GhcTc), LHsCmdTop GhcTc, TcCoercion)
forall a b. (a -> b) -> a -> b
$
    do  { TcType
exp_ty <- ExpRhoType -> TcM TcType
expTypeToType ExpRhoType
exp_ty  -- no higher-rank stuff with arrows
        ; (TcCoercion
co, (TcType
exp_ty1, TcType
res_ty)) <- TcType -> TcM (TcCoercion, (TcType, TcType))
matchExpectedAppTy TcType
exp_ty
        ; (TcCoercion
co1, (TcType
arr_ty, TcType
arg_ty)) <- TcType -> TcM (TcCoercion, (TcType, TcType))
matchExpectedAppTy TcType
exp_ty1
        ; let cmd_env :: CmdEnv
cmd_env = CmdEnv :: TcType -> CmdEnv
CmdEnv { cmd_arr :: TcType
cmd_arr = TcType
arr_ty }
        ; (Located (Pat GhcTc)
pat', LHsCmdTop GhcTc
cmd') <- HsMatchContext GhcRn
-> LPat GhcRn
-> Scaled TcType
-> TcM (LHsCmdTop GhcTc)
-> TcM (LPat GhcTc, LHsCmdTop GhcTc)
forall a.
HsMatchContext GhcRn
-> LPat GhcRn -> Scaled TcType -> TcM a -> TcM (LPat GhcTc, a)
tcCheckPat HsMatchContext GhcRn
forall p. HsMatchContext p
ProcExpr LPat GhcRn
pat (TcType -> Scaled TcType
forall a. a -> Scaled a
unrestricted TcType
arg_ty) (TcM (LHsCmdTop GhcTc) -> TcM (LPat GhcTc, LHsCmdTop GhcTc))
-> TcM (LHsCmdTop GhcTc) -> TcM (LPat GhcTc, LHsCmdTop GhcTc)
forall a b. (a -> b) -> a -> b
$
                          CmdEnv
-> LHsCmdTop GhcRn -> (TcType, TcType) -> TcM (LHsCmdTop GhcTc)
tcCmdTop CmdEnv
cmd_env LHsCmdTop GhcRn
cmd (TcType
unitTy, TcType
res_ty)
        ; let res_co :: TcCoercion
res_co = TcCoercion -> TcCoercion -> TcCoercion
mkTcTransCo TcCoercion
co
                         (TcCoercion -> TcCoercion -> TcCoercion
mkTcAppCo TcCoercion
co1 (TcType -> TcCoercion
mkTcNomReflCo TcType
res_ty))
        ; (Located (Pat GhcTc), LHsCmdTop GhcTc, TcCoercion)
-> TcM (Located (Pat GhcTc), LHsCmdTop GhcTc, TcCoercion)
forall (m :: * -> *) a. Monad m => a -> m a
return (Located (Pat GhcTc)
pat', LHsCmdTop GhcTc
cmd', TcCoercion
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
         -> LHsCmdTop GhcRn
         -> CmdType
         -> TcM (LHsCmdTop GhcTc)

tcCmdTop :: CmdEnv
-> LHsCmdTop GhcRn -> (TcType, TcType) -> TcM (LHsCmdTop GhcTc)
tcCmdTop CmdEnv
env (L SrcSpan
loc (HsCmdTop XCmdTop GhcRn
names LHsCmd GhcRn
cmd)) cmd_ty :: (TcType, TcType)
cmd_ty@(TcType
cmd_stk, TcType
res_ty)
  = SrcSpan -> TcM (LHsCmdTop GhcTc) -> TcM (LHsCmdTop GhcTc)
forall a. SrcSpan -> TcRn a -> TcRn a
setSrcSpan SrcSpan
loc (TcM (LHsCmdTop GhcTc) -> TcM (LHsCmdTop GhcTc))
-> TcM (LHsCmdTop GhcTc) -> TcM (LHsCmdTop GhcTc)
forall a b. (a -> b) -> a -> b
$
    do  { LHsCmd GhcTc
cmd'   <- CmdEnv -> LHsCmd GhcRn -> (TcType, TcType) -> TcM (LHsCmd GhcTc)
tcCmd CmdEnv
env LHsCmd GhcRn
cmd (TcType, TcType)
cmd_ty
        ; [(Name, HsExpr GhcTc)]
names' <- ((Name, HsExpr GhcRn)
 -> IOEnv (Env TcGblEnv TcLclEnv) (Name, HsExpr GhcTc))
-> [(Name, HsExpr GhcRn)]
-> IOEnv (Env TcGblEnv TcLclEnv) [(Name, HsExpr GhcTc)]
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
mapM (CtOrigin
-> TcType
-> (Name, HsExpr GhcRn)
-> IOEnv (Env TcGblEnv TcLclEnv) (Name, HsExpr GhcTc)
tcSyntaxName CtOrigin
ProcOrigin (CmdEnv -> TcType
cmd_arr CmdEnv
env)) [(Name, HsExpr GhcRn)]
XCmdTop GhcRn
names
        ; LHsCmdTop GhcTc -> TcM (LHsCmdTop GhcTc)
forall (m :: * -> *) a. Monad m => a -> m a
return (SrcSpan -> HsCmdTop GhcTc -> LHsCmdTop GhcTc
forall l e. l -> e -> GenLocated l e
L SrcSpan
loc (HsCmdTop GhcTc -> LHsCmdTop GhcTc)
-> HsCmdTop GhcTc -> LHsCmdTop GhcTc
forall a b. (a -> b) -> a -> b
$ XCmdTop GhcTc -> LHsCmd GhcTc -> HsCmdTop GhcTc
forall p. XCmdTop p -> LHsCmd p -> HsCmdTop p
HsCmdTop (TcType -> TcType -> [(Name, HsExpr GhcTc)] -> CmdTopTc
CmdTopTc TcType
cmd_stk TcType
res_ty [(Name, HsExpr GhcTc)]
names') LHsCmd GhcTc
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 SrcSpan
loc HsCmd GhcRn
cmd) (TcType, TcType)
res_ty
  = SrcSpan -> TcM (LHsCmd GhcTc) -> TcM (LHsCmd GhcTc)
forall a. SrcSpan -> TcRn a -> TcRn a
setSrcSpan SrcSpan
loc (TcM (LHsCmd GhcTc) -> TcM (LHsCmd GhcTc))
-> TcM (LHsCmd GhcTc) -> TcM (LHsCmd GhcTc)
forall a b. (a -> b) -> a -> b
$ do
        { HsCmd GhcTc
cmd' <- CmdEnv -> HsCmd GhcRn -> (TcType, TcType) -> TcM (HsCmd GhcTc)
tc_cmd CmdEnv
env HsCmd GhcRn
cmd (TcType, TcType)
res_ty
        ; LHsCmd GhcTc -> TcM (LHsCmd GhcTc)
forall (m :: * -> *) a. Monad m => a -> m a
return (SrcSpan -> HsCmd GhcTc -> LHsCmd GhcTc
forall l e. l -> e -> GenLocated l e
L SrcSpan
loc HsCmd GhcTc
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  { LHsCmd GhcTc
cmd' <- CmdEnv -> LHsCmd GhcRn -> (TcType, TcType) -> TcM (LHsCmd GhcTc)
tcCmd CmdEnv
env LHsCmd GhcRn
cmd (TcType, TcType)
res_ty
        ; HsCmd GhcTc -> TcM (HsCmd GhcTc)
forall (m :: * -> *) a. Monad m => a -> m a
return (XCmdPar GhcTc -> LHsCmd GhcTc -> HsCmd GhcTc
forall id. XCmdPar id -> LHsCmd id -> HsCmd id
HsCmdPar XCmdPar GhcRn
XCmdPar GhcTc
x LHsCmd GhcTc
cmd') }

tc_cmd CmdEnv
env (HsCmdLet XCmdLet GhcRn
x (L SrcSpan
l HsLocalBinds GhcRn
binds) (L SrcSpan
body_loc HsCmd GhcRn
body)) (TcType, TcType)
res_ty
  = do  { (HsLocalBinds GhcTc
binds', HsCmd GhcTc
body') <- HsLocalBinds GhcRn
-> TcM (HsCmd GhcTc) -> TcM (HsLocalBinds GhcTc, HsCmd GhcTc)
forall thing.
HsLocalBinds GhcRn -> TcM thing -> TcM (HsLocalBinds GhcTc, thing)
tcLocalBinds HsLocalBinds GhcRn
binds         (TcM (HsCmd GhcTc) -> TcM (HsLocalBinds GhcTc, HsCmd GhcTc))
-> TcM (HsCmd GhcTc) -> TcM (HsLocalBinds GhcTc, HsCmd GhcTc)
forall a b. (a -> b) -> a -> b
$
                             SrcSpan -> TcM (HsCmd GhcTc) -> TcM (HsCmd GhcTc)
forall a. SrcSpan -> TcRn a -> TcRn a
setSrcSpan SrcSpan
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
        ; HsCmd GhcTc -> TcM (HsCmd GhcTc)
forall (m :: * -> *) a. Monad m => a -> m a
return (XCmdLet GhcTc -> LHsLocalBinds GhcTc -> LHsCmd GhcTc -> HsCmd GhcTc
forall id. XCmdLet id -> LHsLocalBinds id -> LHsCmd id -> HsCmd id
HsCmdLet XCmdLet GhcRn
XCmdLet GhcTc
x (SrcSpan -> HsLocalBinds GhcTc -> LHsLocalBinds GhcTc
forall l e. l -> e -> GenLocated l e
L SrcSpan
l HsLocalBinds GhcTc
binds') (SrcSpan -> HsCmd GhcTc -> LHsCmd GhcTc
forall l e. l -> e -> GenLocated l e
L SrcSpan
body_loc HsCmd GhcTc
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)
  = MsgDoc -> TcM (HsCmd GhcTc) -> TcM (HsCmd GhcTc)
forall a. MsgDoc -> TcM a -> TcM a
addErrCtxt (HsCmd GhcRn -> MsgDoc
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
      (LHsExpr GhcTc
scrut', TcType
scrut_ty) <- LHsExpr GhcRn -> TcM (LHsExpr GhcTc, TcType)
tcInferRho LHsExpr GhcRn
scrut
      MatchGroup GhcTc (LHsCmd GhcTc)
matches' <- CmdEnv
-> TcType
-> MatchGroup GhcRn (LHsCmd GhcRn)
-> (TcType, TcType)
-> TcM (MatchGroup GhcTc (LHsCmd GhcTc))
tcCmdMatches CmdEnv
env TcType
scrut_ty MatchGroup GhcRn (LHsCmd GhcRn)
matches (TcType
stk, TcType
res_ty)
      HsCmd GhcTc -> TcM (HsCmd GhcTc)
forall (m :: * -> *) a. Monad m => a -> m a
return (XCmdCase GhcTc
-> LHsExpr GhcTc -> MatchGroup GhcTc (LHsCmd GhcTc) -> HsCmd GhcTc
forall id.
XCmdCase id -> LHsExpr id -> MatchGroup id (LHsCmd id) -> HsCmd id
HsCmdCase XCmdCase GhcRn
XCmdCase GhcTc
x LHsExpr GhcTc
scrut' MatchGroup GhcTc (LHsCmd GhcTc)
matches')

tc_cmd CmdEnv
env in_cmd :: HsCmd GhcRn
in_cmd@(HsCmdLamCase XCmdLamCase GhcRn
x MatchGroup GhcRn (LHsCmd GhcRn)
matches) (TcType
stk, TcType
res_ty)
  = MsgDoc -> TcM (HsCmd GhcTc) -> TcM (HsCmd GhcTc)
forall a. MsgDoc -> TcM a -> TcM a
addErrCtxt (HsCmd GhcRn -> MsgDoc
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
      (TcCoercion
co, [TcType
scrut_ty], TcType
stk') <- Arity -> TcType -> TcM (TcCoercion, [TcType], TcType)
matchExpectedCmdArgs Arity
1 TcType
stk
      MatchGroup GhcTc (LHsCmd GhcTc)
matches' <- CmdEnv
-> TcType
-> MatchGroup GhcRn (LHsCmd GhcRn)
-> (TcType, TcType)
-> TcM (MatchGroup GhcTc (LHsCmd GhcTc))
tcCmdMatches CmdEnv
env TcType
scrut_ty MatchGroup GhcRn (LHsCmd GhcRn)
matches (TcType
stk', TcType
res_ty)
      HsCmd GhcTc -> TcM (HsCmd GhcTc)
forall (m :: * -> *) a. Monad m => a -> m a
return (HsWrapper -> HsCmd GhcTc -> HsCmd GhcTc
mkHsCmdWrap (TcCoercion -> HsWrapper
mkWpCastN TcCoercion
co) (XCmdLamCase GhcTc -> MatchGroup GhcTc (LHsCmd GhcTc) -> HsCmd GhcTc
forall id. XCmdLamCase id -> MatchGroup id (LHsCmd id) -> HsCmd id
HsCmdLamCase XCmdLamCase GhcRn
XCmdLamCase GhcTc
x MatchGroup GhcTc (LHsCmd GhcTc)
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  { LHsExpr GhcTc
pred' <- LHsExpr GhcRn -> TcType -> TcM (LHsExpr GhcTc)
tcCheckMonoExpr LHsExpr GhcRn
pred TcType
boolTy
        ; LHsCmd GhcTc
b1'   <- CmdEnv -> LHsCmd GhcRn -> (TcType, TcType) -> TcM (LHsCmd GhcTc)
tcCmd CmdEnv
env LHsCmd GhcRn
b1 (TcType, TcType)
res_ty
        ; LHsCmd GhcTc
b2'   <- CmdEnv -> LHsCmd GhcRn -> (TcType, TcType) -> TcM (LHsCmd GhcTc)
tcCmd CmdEnv
env LHsCmd GhcRn
b2 (TcType, TcType)
res_ty
        ; HsCmd GhcTc -> TcM (HsCmd GhcTc)
forall (m :: * -> *) a. Monad m => a -> m a
return (XCmdIf GhcTc
-> SyntaxExpr GhcTc
-> LHsExpr GhcTc
-> LHsCmd GhcTc
-> LHsCmd GhcTc
-> HsCmd GhcTc
forall id.
XCmdIf id
-> SyntaxExpr id
-> LHsExpr id
-> LHsCmd id
-> LHsCmd id
-> HsCmd id
HsCmdIf XCmdIf GhcRn
XCmdIf GhcTc
x SyntaxExpr GhcTc
SyntaxExprTc
NoSyntaxExprTc LHsExpr GhcTc
pred' LHsCmd GhcTc
b1' LHsCmd GhcTc
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  { TcType
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.
        ; (TCvSubst
_, [TcTyVar
r_tv]) <- [TcTyVar] -> TcM (TCvSubst, [TcTyVar])
tcInstSkolTyVars [TcTyVar
alphaTyVar]
        ; let r_ty :: TcType
r_ty = TcTyVar -> TcType
mkTyVarTy TcTyVar
r_tv
        ; Bool -> MsgDoc -> TcM ()
checkTc (Bool -> Bool
not (TcTyVar
r_tv TcTyVar -> VarSet -> Bool
`elemVarSet` TcType -> VarSet
tyCoVarsOfType TcType
pred_ty))
                  (String -> MsgDoc
text String
"Predicate type of `ifThenElse' depends on result type")
        ; (LHsExpr GhcTc
pred', SyntaxExprTc
fun')
            <- CtOrigin
-> SyntaxExprRn
-> [SyntaxOpType]
-> ExpRhoType
-> ([TcType] -> [TcType] -> TcM (LHsExpr GhcTc))
-> TcM (LHsExpr GhcTc, SyntaxExprTc)
forall a.
CtOrigin
-> SyntaxExprRn
-> [SyntaxOpType]
-> ExpRhoType
-> ([TcType] -> [TcType] -> TcM a)
-> TcM (a, SyntaxExprTc)
tcSyntaxOp CtOrigin
IfOrigin SyntaxExpr GhcRn
SyntaxExprRn
fun ((TcType -> SyntaxOpType) -> [TcType] -> [SyntaxOpType]
forall a b. (a -> b) -> [a] -> [b]
map TcType -> SyntaxOpType
synKnownType [TcType
pred_ty, TcType
r_ty, TcType
r_ty])
                                       (TcType -> ExpRhoType
mkCheckExpType TcType
r_ty) (([TcType] -> [TcType] -> TcM (LHsExpr GhcTc))
 -> TcM (LHsExpr GhcTc, SyntaxExprTc))
-> ([TcType] -> [TcType] -> TcM (LHsExpr GhcTc))
-> TcM (LHsExpr GhcTc, SyntaxExprTc)
forall a b. (a -> b) -> a -> b
$ \ [TcType]
_ [TcType]
_ ->
               LHsExpr GhcRn -> TcType -> TcM (LHsExpr GhcTc)
tcCheckMonoExpr LHsExpr GhcRn
pred TcType
pred_ty

        ; LHsCmd GhcTc
b1'   <- CmdEnv -> LHsCmd GhcRn -> (TcType, TcType) -> TcM (LHsCmd GhcTc)
tcCmd CmdEnv
env LHsCmd GhcRn
b1 (TcType, TcType)
res_ty
        ; LHsCmd GhcTc
b2'   <- CmdEnv -> LHsCmd GhcRn -> (TcType, TcType) -> TcM (LHsCmd GhcTc)
tcCmd CmdEnv
env LHsCmd GhcRn
b2 (TcType, TcType)
res_ty
        ; HsCmd GhcTc -> TcM (HsCmd GhcTc)
forall (m :: * -> *) a. Monad m => a -> m a
return (XCmdIf GhcTc
-> SyntaxExpr GhcTc
-> LHsExpr GhcTc
-> LHsCmd GhcTc
-> LHsCmd GhcTc
-> HsCmd GhcTc
forall id.
XCmdIf id
-> SyntaxExpr id
-> LHsExpr id
-> LHsCmd id
-> LHsCmd id
-> HsCmd id
HsCmdIf XCmdIf GhcRn
XCmdIf GhcTc
x SyntaxExpr GhcTc
SyntaxExprTc
fun' LHsExpr GhcTc
pred' LHsCmd GhcTc
b1' LHsCmd GhcTc
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)
  = MsgDoc -> TcM (HsCmd GhcTc) -> TcM (HsCmd GhcTc)
forall a. MsgDoc -> TcM a -> TcM a
addErrCtxt (HsCmd GhcRn -> MsgDoc
cmdCtxt HsCmd GhcRn
cmd)    (TcM (HsCmd GhcTc) -> TcM (HsCmd GhcTc))
-> TcM (HsCmd GhcTc) -> TcM (HsCmd GhcTc)
forall a b. (a -> b) -> a -> b
$
    do  { TcType
arg_ty <- TcM TcType
newOpenFlexiTyVarTy
        ; let fun_ty :: TcType
fun_ty = CmdEnv -> TcType -> TcType -> TcType
mkCmdArrTy CmdEnv
env TcType
arg_ty TcType
res_ty
        ; LHsExpr GhcTc
fun' <- TcM (LHsExpr GhcTc) -> TcM (LHsExpr GhcTc)
select_arrow_scope (LHsExpr GhcRn -> TcType -> TcM (LHsExpr GhcTc)
tcCheckMonoExpr LHsExpr GhcRn
fun TcType
fun_ty)

        ; LHsExpr GhcTc
arg' <- LHsExpr GhcRn -> TcType -> TcM (LHsExpr GhcTc)
tcCheckMonoExpr LHsExpr GhcRn
arg TcType
arg_ty

        ; HsCmd GhcTc -> TcM (HsCmd GhcTc)
forall (m :: * -> *) a. Monad m => a -> m a
return (XCmdArrApp GhcTc
-> LHsExpr GhcTc
-> LHsExpr GhcTc
-> HsArrAppType
-> Bool
-> HsCmd GhcTc
forall id.
XCmdArrApp id
-> LHsExpr id -> LHsExpr id -> HsArrAppType -> Bool -> HsCmd id
HsCmdArrApp TcType
XCmdArrApp GhcTc
fun_ty LHsExpr GhcTc
fun' LHsExpr GhcTc
arg' HsArrAppType
ho_app Bool
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 :: TcM (LHsExpr GhcTc) -> TcM (LHsExpr GhcTc)
select_arrow_scope TcM (LHsExpr GhcTc)
tc = case HsArrAppType
ho_app of
        HsArrAppType
HsHigherOrderApp -> TcM (LHsExpr GhcTc)
tc
        HsArrAppType
HsFirstOrderApp  -> TcM (LHsExpr GhcTc) -> TcM (LHsExpr GhcTc)
forall a. TcM a -> TcM a
escapeArrowScope TcM (LHsExpr 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)
  = MsgDoc -> TcM (HsCmd GhcTc) -> TcM (HsCmd GhcTc)
forall a. MsgDoc -> TcM a -> TcM a
addErrCtxt (HsCmd GhcRn -> MsgDoc
cmdCtxt HsCmd GhcRn
cmd)    (TcM (HsCmd GhcTc) -> TcM (HsCmd GhcTc))
-> TcM (HsCmd GhcTc) -> TcM (HsCmd GhcTc)
forall a b. (a -> b) -> a -> b
$
    do  { TcType
arg_ty <- TcM TcType
newOpenFlexiTyVarTy
        ; LHsCmd GhcTc
fun'   <- CmdEnv -> LHsCmd GhcRn -> (TcType, TcType) -> TcM (LHsCmd GhcTc)
tcCmd CmdEnv
env LHsCmd GhcRn
fun (TcType -> TcType -> TcType
mkPairTy TcType
arg_ty TcType
cmd_stk, TcType
res_ty)
        ; LHsExpr GhcTc
arg'   <- LHsExpr GhcRn -> TcType -> TcM (LHsExpr GhcTc)
tcCheckMonoExpr LHsExpr GhcRn
arg TcType
arg_ty
        ; HsCmd GhcTc -> TcM (HsCmd GhcTc)
forall (m :: * -> *) a. Monad m => a -> m a
return (XCmdApp GhcTc -> LHsCmd GhcTc -> LHsExpr GhcTc -> HsCmd GhcTc
forall id. XCmdApp id -> LHsCmd id -> LHsExpr id -> HsCmd id
HsCmdApp XCmdApp GhcRn
XCmdApp GhcTc
x LHsCmd GhcTc
fun' LHsExpr GhcTc
arg') }

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

tc_cmd CmdEnv
env
       (HsCmdLam XCmdLam GhcRn
x (MG { mg_alts :: forall p body. MatchGroup p body -> Located [LMatch p body]
mg_alts = L SrcSpan
l [L SrcSpan
mtch_loc
                                   (match :: Match GhcRn (LHsCmd GhcRn)
match@(Match { m_pats :: forall p body. Match p body -> [LPat p]
m_pats = [LPat GhcRn]
pats, m_grhss :: forall p body. Match p body -> GRHSs p body
m_grhss = GRHSs GhcRn (LHsCmd GhcRn)
grhss }))],
                         mg_origin :: forall p body. MatchGroup p body -> Origin
mg_origin = Origin
origin }))
       (TcType
cmd_stk, TcType
res_ty)
  = MsgDoc -> TcM (HsCmd GhcTc) -> TcM (HsCmd GhcTc)
forall a. MsgDoc -> TcM a -> TcM a
addErrCtxt (Match GhcRn (LHsCmd GhcRn) -> MsgDoc
forall (idR :: Pass) body.
(OutputableBndrId idR, Outputable body) =>
Match (GhcPass idR) body -> MsgDoc
pprMatchInCtxt Match GhcRn (LHsCmd GhcRn)
match)        (TcM (HsCmd GhcTc) -> TcM (HsCmd GhcTc))
-> TcM (HsCmd GhcTc) -> TcM (HsCmd GhcTc)
forall a b. (a -> b) -> a -> b
$
    do  { (TcCoercion
co, [TcType]
arg_tys, TcType
cmd_stk') <- Arity -> TcType -> TcM (TcCoercion, [TcType], TcType)
matchExpectedCmdArgs Arity
n_pats TcType
cmd_stk

                -- Check the patterns, and the GRHSs inside
        ; ([Located (Pat GhcTc)]
pats', GRHSs GhcTc (LHsCmd GhcTc)
grhss') <- SrcSpan
-> TcRn ([Located (Pat GhcTc)], GRHSs GhcTc (LHsCmd GhcTc))
-> TcRn ([Located (Pat GhcTc)], GRHSs GhcTc (LHsCmd GhcTc))
forall a. SrcSpan -> TcRn a -> TcRn a
setSrcSpan SrcSpan
mtch_loc                                 (TcRn ([Located (Pat GhcTc)], GRHSs GhcTc (LHsCmd GhcTc))
 -> TcRn ([Located (Pat GhcTc)], GRHSs GhcTc (LHsCmd GhcTc)))
-> TcRn ([Located (Pat GhcTc)], GRHSs GhcTc (LHsCmd GhcTc))
-> TcRn ([Located (Pat GhcTc)], GRHSs GhcTc (LHsCmd GhcTc))
forall a b. (a -> b) -> a -> b
$
                             HsMatchContext GhcRn
-> [LPat GhcRn]
-> [Scaled ExpRhoType]
-> TcM (GRHSs GhcTc (LHsCmd GhcTc))
-> TcM ([LPat GhcTc], GRHSs GhcTc (LHsCmd GhcTc))
forall a.
HsMatchContext GhcRn
-> [LPat GhcRn]
-> [Scaled ExpRhoType]
-> TcM a
-> TcM ([LPat GhcTc], a)
tcPats HsMatchContext GhcRn
forall p. HsMatchContext p
LambdaExpr [LPat GhcRn]
pats ((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) (TcM (GRHSs GhcTc (LHsCmd GhcTc))
 -> TcM ([LPat GhcTc], GRHSs GhcTc (LHsCmd GhcTc)))
-> TcM (GRHSs GhcTc (LHsCmd GhcTc))
-> TcM ([LPat GhcTc], GRHSs GhcTc (LHsCmd GhcTc))
forall a b. (a -> b) -> a -> b
$
                             GRHSs GhcRn (LHsCmd GhcRn)
-> TcType -> ExpRhoType -> TcM (GRHSs GhcTc (LHsCmd GhcTc))
tc_grhss GRHSs GhcRn (LHsCmd GhcRn)
grhss TcType
cmd_stk' (TcType -> ExpRhoType
mkCheckExpType TcType
res_ty)

        ; let match' :: GenLocated SrcSpan (Match GhcTc (LHsCmd GhcTc))
match' = SrcSpan
-> Match GhcTc (LHsCmd GhcTc)
-> GenLocated SrcSpan (Match GhcTc (LHsCmd GhcTc))
forall l e. l -> e -> GenLocated l e
L SrcSpan
mtch_loc (Match :: forall p body.
XCMatch p body
-> HsMatchContext (NoGhcTc p)
-> [LPat p]
-> GRHSs p body
-> Match p body
Match { m_ext :: XCMatch GhcTc (LHsCmd GhcTc)
m_ext = NoExtField
XCMatch GhcTc (LHsCmd GhcTc)
noExtField
                                         , m_ctxt :: HsMatchContext (NoGhcTc GhcTc)
m_ctxt = HsMatchContext (NoGhcTc GhcTc)
forall p. HsMatchContext p
LambdaExpr, m_pats :: [LPat GhcTc]
m_pats = [Located (Pat GhcTc)]
[LPat GhcTc]
pats'
                                         , m_grhss :: GRHSs GhcTc (LHsCmd GhcTc)
m_grhss = GRHSs GhcTc (LHsCmd GhcTc)
grhss' })
              arg_tys :: [Scaled TcType]
arg_tys = (Located (Pat GhcTc) -> Scaled TcType)
-> [Located (Pat GhcTc)] -> [Scaled TcType]
forall a b. (a -> b) -> [a] -> [b]
map (TcType -> Scaled TcType
forall a. a -> Scaled a
unrestricted (TcType -> Scaled TcType)
-> (Located (Pat GhcTc) -> TcType)
-> Located (Pat GhcTc)
-> Scaled TcType
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Located (Pat GhcTc) -> TcType
LPat GhcTc -> TcType
hsLPatType) [Located (Pat GhcTc)]
pats'
              cmd' :: HsCmd GhcTc
cmd' = XCmdLam GhcTc -> MatchGroup GhcTc (LHsCmd GhcTc) -> HsCmd GhcTc
forall id. XCmdLam id -> MatchGroup id (LHsCmd id) -> HsCmd id
HsCmdLam XCmdLam GhcRn
XCmdLam GhcTc
x (MG :: forall p body.
XMG p body
-> Located [LMatch p body] -> Origin -> MatchGroup p body
MG { mg_alts :: Located [GenLocated SrcSpan (Match GhcTc (LHsCmd GhcTc))]
mg_alts = SrcSpan
-> [GenLocated SrcSpan (Match GhcTc (LHsCmd GhcTc))]
-> Located [GenLocated SrcSpan (Match GhcTc (LHsCmd GhcTc))]
forall l e. l -> e -> GenLocated l e
L SrcSpan
l [GenLocated SrcSpan (Match GhcTc (LHsCmd GhcTc))
match']
                                    , mg_ext :: XMG GhcTc (LHsCmd GhcTc)
mg_ext = [Scaled TcType] -> TcType -> MatchGroupTc
MatchGroupTc [Scaled TcType]
arg_tys TcType
res_ty
                                    , mg_origin :: Origin
mg_origin = Origin
origin })
        ; HsCmd GhcTc -> TcM (HsCmd GhcTc)
forall (m :: * -> *) a. Monad m => a -> m a
return (HsWrapper -> HsCmd GhcTc -> HsCmd GhcTc
mkHsCmdWrap (TcCoercion -> HsWrapper
mkWpCastN TcCoercion
co) HsCmd GhcTc
cmd') }
  where
    n_pats :: Arity
n_pats     = [Located (Pat GhcRn)] -> Arity
forall (t :: * -> *) a. Foldable t => t a -> Arity
length [Located (Pat GhcRn)]
[LPat GhcRn]
pats
    match_ctxt :: HsMatchContext GhcRn
match_ctxt = (HsMatchContext GhcRn
forall p. HsMatchContext p
LambdaExpr :: HsMatchContext GhcRn)    -- Maybe KappaExpr?
    pg_ctxt :: HsStmtContext GhcRn
pg_ctxt    = HsMatchContext GhcRn -> HsStmtContext GhcRn
forall p. HsMatchContext p -> HsStmtContext p
PatGuard HsMatchContext GhcRn
match_ctxt

    tc_grhss :: GRHSs GhcRn (LHsCmd GhcRn)
-> TcType -> ExpRhoType -> TcM (GRHSs GhcTc (LHsCmd GhcTc))
tc_grhss (GRHSs XCGRHSs GhcRn (LHsCmd GhcRn)
x [LGRHS GhcRn (LHsCmd GhcRn)]
grhss (L SrcSpan
l HsLocalBinds GhcRn
binds)) TcType
stk_ty ExpRhoType
res_ty
        = do { (HsLocalBinds GhcTc
binds', [Located (GRHS GhcTc (LHsCmd GhcTc))]
grhss') <- HsLocalBinds GhcRn
-> TcM [Located (GRHS GhcTc (LHsCmd GhcTc))]
-> TcM (HsLocalBinds GhcTc, [Located (GRHS GhcTc (LHsCmd GhcTc))])
forall thing.
HsLocalBinds GhcRn -> TcM thing -> TcM (HsLocalBinds GhcTc, thing)
tcLocalBinds HsLocalBinds GhcRn
binds (TcM [Located (GRHS GhcTc (LHsCmd GhcTc))]
 -> TcM (HsLocalBinds GhcTc, [Located (GRHS GhcTc (LHsCmd GhcTc))]))
-> TcM [Located (GRHS GhcTc (LHsCmd GhcTc))]
-> TcM (HsLocalBinds GhcTc, [Located (GRHS GhcTc (LHsCmd GhcTc))])
forall a b. (a -> b) -> a -> b
$
                                   (LGRHS GhcRn (LHsCmd GhcRn)
 -> IOEnv
      (Env TcGblEnv TcLclEnv) (Located (GRHS GhcTc (LHsCmd GhcTc))))
-> [LGRHS GhcRn (LHsCmd GhcRn)]
-> TcM [Located (GRHS GhcTc (LHsCmd GhcTc))]
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
mapM ((GRHS GhcRn (LHsCmd GhcRn) -> TcM (GRHS GhcTc (LHsCmd GhcTc)))
-> LGRHS GhcRn (LHsCmd GhcRn)
-> IOEnv
     (Env TcGblEnv TcLclEnv) (Located (GRHS GhcTc (LHsCmd GhcTc)))
forall a b. (a -> TcM b) -> Located a -> TcM (Located b)
wrapLocM (TcType
-> ExpRhoType
-> GRHS GhcRn (LHsCmd GhcRn)
-> TcM (GRHS GhcTc (LHsCmd GhcTc))
tc_grhs TcType
stk_ty ExpRhoType
res_ty)) [LGRHS GhcRn (LHsCmd GhcRn)]
grhss
             ; GRHSs GhcTc (LHsCmd GhcTc) -> TcM (GRHSs GhcTc (LHsCmd GhcTc))
forall (m :: * -> *) a. Monad m => a -> m a
return (XCGRHSs GhcTc (LHsCmd GhcTc)
-> [Located (GRHS GhcTc (LHsCmd GhcTc))]
-> LHsLocalBinds GhcTc
-> GRHSs GhcTc (LHsCmd GhcTc)
forall p body.
XCGRHSs p body -> [LGRHS p body] -> LHsLocalBinds p -> GRHSs p body
GRHSs XCGRHSs GhcRn (LHsCmd GhcRn)
XCGRHSs GhcTc (LHsCmd GhcTc)
x [Located (GRHS GhcTc (LHsCmd GhcTc))]
grhss' (SrcSpan -> HsLocalBinds GhcTc -> LHsLocalBinds GhcTc
forall l e. l -> e -> GenLocated l e
L SrcSpan
l HsLocalBinds GhcTc
binds')) }

    tc_grhs :: TcType
-> ExpRhoType
-> GRHS GhcRn (LHsCmd GhcRn)
-> TcM (GRHS GhcTc (LHsCmd GhcTc))
tc_grhs TcType
stk_ty ExpRhoType
res_ty (GRHS XCGRHS GhcRn (LHsCmd GhcRn)
x [GuardLStmt GhcRn]
guards LHsCmd GhcRn
body)
        = do { ([LStmt GhcTc (LHsExpr GhcTc)]
guards', LHsCmd GhcTc
rhs') <- HsStmtContext GhcRn
-> TcStmtChecker HsExpr ExpRhoType
-> [GuardLStmt GhcRn]
-> ExpRhoType
-> (ExpRhoType -> TcM (LHsCmd GhcTc))
-> TcM ([LStmt GhcTc (LHsExpr GhcTc)], LHsCmd GhcTc)
forall (body :: * -> *) rho_type thing.
Outputable (body GhcRn) =>
HsStmtContext GhcRn
-> TcStmtChecker body rho_type
-> [LStmt GhcRn (Located (body GhcRn))]
-> rho_type
-> (rho_type -> TcM thing)
-> TcM ([LStmt GhcTc (Located (body GhcTc))], thing)
tcStmtsAndThen HsStmtContext GhcRn
pg_ctxt TcStmtChecker HsExpr ExpRhoType
tcGuardStmt [GuardLStmt GhcRn]
guards ExpRhoType
res_ty ((ExpRhoType -> TcM (LHsCmd GhcTc))
 -> TcM ([LStmt GhcTc (LHsExpr GhcTc)], LHsCmd GhcTc))
-> (ExpRhoType -> TcM (LHsCmd GhcTc))
-> TcM ([LStmt GhcTc (LHsExpr GhcTc)], LHsCmd GhcTc)
forall a b. (a -> b) -> a -> b
$
                                  \ ExpRhoType
res_ty -> CmdEnv -> LHsCmd GhcRn -> (TcType, TcType) -> TcM (LHsCmd GhcTc)
tcCmd CmdEnv
env LHsCmd GhcRn
body
                                                (TcType
stk_ty, String -> ExpRhoType -> TcType
checkingExpType String
"tc_grhs" ExpRhoType
res_ty)
             ; GRHS GhcTc (LHsCmd GhcTc) -> TcM (GRHS GhcTc (LHsCmd GhcTc))
forall (m :: * -> *) a. Monad m => a -> m a
return (XCGRHS GhcTc (LHsCmd GhcTc)
-> [LStmt GhcTc (LHsExpr GhcTc)]
-> LHsCmd GhcTc
-> GRHS GhcTc (LHsCmd GhcTc)
forall p body.
XCGRHS p body -> [GuardLStmt p] -> body -> GRHS p body
GRHS XCGRHS GhcRn (LHsCmd GhcRn)
XCGRHS GhcTc (LHsCmd GhcTc)
x [LStmt GhcTc (LHsExpr GhcTc)]
guards' LHsCmd GhcTc
rhs') }

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

tc_cmd CmdEnv
env (HsCmdDo XCmdDo GhcRn
_ (L SrcSpan
l [CmdLStmt GhcRn]
stmts) ) (TcType
cmd_stk, TcType
res_ty)
  = do  { TcCoercion
co <- Maybe (HsExpr GhcRn) -> TcType -> TcType -> TcM TcCoercion
unifyType Maybe (HsExpr GhcRn)
forall a. Maybe a
Nothing TcType
unitTy TcType
cmd_stk  -- Expecting empty argument stack
        ; [LStmt GhcTc (LHsCmd GhcTc)]
stmts' <- HsStmtContext GhcRn
-> TcStmtChecker HsCmd TcType
-> [CmdLStmt GhcRn]
-> TcType
-> TcM [LStmt GhcTc (LHsCmd GhcTc)]
forall (body :: * -> *) rho_type.
Outputable (body GhcRn) =>
HsStmtContext GhcRn
-> TcStmtChecker body rho_type
-> [LStmt GhcRn (Located (body GhcRn))]
-> rho_type
-> TcM [LStmt GhcTc (Located (body GhcTc))]
tcStmts HsStmtContext GhcRn
forall p. HsStmtContext p
ArrowExpr (CmdEnv -> TcStmtChecker HsCmd TcType
tcArrDoStmt CmdEnv
env) [CmdLStmt GhcRn]
stmts TcType
res_ty
        ; HsCmd GhcTc -> TcM (HsCmd GhcTc)
forall (m :: * -> *) a. Monad m => a -> m a
return (HsWrapper -> HsCmd GhcTc -> HsCmd GhcTc
mkHsCmdWrap (TcCoercion -> HsWrapper
mkWpCastN TcCoercion
co) (XCmdDo GhcTc -> Located [LStmt GhcTc (LHsCmd GhcTc)] -> HsCmd GhcTc
forall id. XCmdDo id -> Located [CmdLStmt id] -> HsCmd id
HsCmdDo TcType
XCmdDo GhcTc
res_ty (SrcSpan
-> [LStmt GhcTc (LHsCmd GhcTc)]
-> Located [LStmt GhcTc (LHsCmd GhcTc)]
forall l e. l -> e -> GenLocated l e
L SrcSpan
l [LStmt GhcTc (LHsCmd GhcTc)]
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
x LHsExpr GhcRn
expr LexicalFixity
f Maybe Fixity
fixity [LHsCmdTop GhcRn]
cmd_args) (TcType
cmd_stk, TcType
res_ty)
  = MsgDoc -> TcM (HsCmd GhcTc) -> TcM (HsCmd GhcTc)
forall a. MsgDoc -> TcM a -> TcM a
addErrCtxt (HsCmd GhcRn -> MsgDoc
cmdCtxt HsCmd GhcRn
cmd)    (TcM (HsCmd GhcTc) -> TcM (HsCmd GhcTc))
-> TcM (HsCmd GhcTc) -> TcM (HsCmd GhcTc)
forall a b. (a -> b) -> a -> b
$
    do  { ([LHsCmdTop GhcTc]
cmd_args', [TcType]
cmd_tys) <- (LHsCmdTop GhcRn
 -> IOEnv (Env TcGblEnv TcLclEnv) (LHsCmdTop GhcTc, TcType))
-> [LHsCmdTop GhcRn]
-> IOEnv (Env TcGblEnv TcLclEnv) ([LHsCmdTop GhcTc], [TcType])
forall (m :: * -> *) a b c.
Applicative m =>
(a -> m (b, c)) -> [a] -> m ([b], [c])
mapAndUnzipM LHsCmdTop GhcRn
-> IOEnv (Env TcGblEnv TcLclEnv) (LHsCmdTop GhcTc, TcType)
tc_cmd_arg [LHsCmdTop GhcRn]
cmd_args
                              -- We use alphaTyVar for 'w'
        ; let e_ty :: TcType
e_ty = TcTyVar -> TcType -> TcType
mkInfForAllTy TcTyVar
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
        ; LHsExpr GhcTc
expr' <- LHsExpr GhcRn -> TcType -> TcM (LHsExpr GhcTc)
tcCheckPolyExpr LHsExpr GhcRn
expr TcType
e_ty
        ; HsCmd GhcTc -> TcM (HsCmd GhcTc)
forall (m :: * -> *) a. Monad m => a -> m a
return (XCmdArrForm GhcTc
-> LHsExpr GhcTc
-> LexicalFixity
-> Maybe Fixity
-> [LHsCmdTop GhcTc]
-> HsCmd GhcTc
forall id.
XCmdArrForm id
-> LHsExpr id
-> LexicalFixity
-> Maybe Fixity
-> [LHsCmdTop id]
-> HsCmd id
HsCmdArrForm XCmdArrForm GhcRn
XCmdArrForm GhcTc
x LHsExpr GhcTc
expr' LexicalFixity
f Maybe Fixity
fixity [LHsCmdTop GhcTc]
cmd_args') }

  where
    tc_cmd_arg :: LHsCmdTop GhcRn -> TcM (LHsCmdTop GhcTc, TcType)
    tc_cmd_arg :: LHsCmdTop GhcRn
-> IOEnv (Env TcGblEnv TcLclEnv) (LHsCmdTop GhcTc, TcType)
tc_cmd_arg LHsCmdTop GhcRn
cmd
       = do { TcType
arr_ty <- TcType -> TcM TcType
newFlexiTyVarTy TcType
arrowTyConKind
            ; TcType
stk_ty <- TcType -> TcM TcType
newFlexiTyVarTy TcType
liftedTypeKind
            ; TcType
res_ty <- TcType -> TcM TcType
newFlexiTyVarTy TcType
liftedTypeKind
            ; let env' :: CmdEnv
env' = CmdEnv
env { cmd_arr :: TcType
cmd_arr = TcType
arr_ty }
            ; LHsCmdTop GhcTc
cmd' <- CmdEnv
-> LHsCmdTop GhcRn -> (TcType, TcType) -> TcM (LHsCmdTop GhcTc)
tcCmdTop CmdEnv
env' LHsCmdTop GhcRn
cmd (TcType
stk_ty, TcType
res_ty)
            ; (LHsCmdTop GhcTc, TcType)
-> IOEnv (Env TcGblEnv TcLclEnv) (LHsCmdTop GhcTc, TcType)
forall (m :: * -> *) a. Monad m => a -> m a
return (LHsCmdTop GhcTc
cmd',  CmdEnv -> TcType -> TcType -> TcType
mkCmdArrTy CmdEnv
env' (TcType -> TcType -> TcType
mkPairTy TcType
alphaTy TcType
stk_ty) TcType
res_ty) }

-----------------------------------------------------------------
--              Base case for illegal commands
-- This is where expressions that aren't commands get rejected

tc_cmd CmdEnv
_ HsCmd GhcRn
cmd (TcType, TcType)
_
  = MsgDoc -> TcM (HsCmd GhcTc)
forall a. MsgDoc -> TcM a
failWithTc ([MsgDoc] -> MsgDoc
vcat [String -> MsgDoc
text String
"The expression", Arity -> MsgDoc -> MsgDoc
nest Arity
2 (HsCmd GhcRn -> MsgDoc
forall a. Outputable a => a -> MsgDoc
ppr HsCmd GhcRn
cmd),
                      String -> MsgDoc
text String
"was found where an arrow command was expected"])

-- | Typechecking for case command alternatives. Used for both
-- 'HsCmdCase' and 'HsCmdLamCase'.
tcCmdMatches :: CmdEnv
             -> TcType                           -- ^ type of the scrutinee
             -> MatchGroup GhcRn (LHsCmd GhcRn)  -- ^ case alternatives
             -> CmdType
             -> TcM (MatchGroup GhcTc (LHsCmd GhcTc))
tcCmdMatches :: CmdEnv
-> TcType
-> MatchGroup GhcRn (LHsCmd GhcRn)
-> (TcType, TcType)
-> TcM (MatchGroup GhcTc (LHsCmd GhcTc))
tcCmdMatches CmdEnv
env TcType
scrut_ty MatchGroup GhcRn (LHsCmd GhcRn)
matches (TcType
stk, TcType
res_ty)
  = TcMatchCtxt HsCmd
-> Scaled TcType
-> MatchGroup GhcRn (LHsCmd GhcRn)
-> ExpRhoType
-> TcM (MatchGroup GhcTc (LHsCmd GhcTc))
forall (body :: * -> *).
Outputable (body GhcRn) =>
TcMatchCtxt body
-> Scaled TcType
-> MatchGroup GhcRn (Located (body GhcRn))
-> ExpRhoType
-> TcM (MatchGroup GhcTc (Located (body GhcTc)))
tcMatchesCase TcMatchCtxt HsCmd
match_ctxt (TcType -> Scaled TcType
forall a. a -> Scaled a
unrestricted TcType
scrut_ty) MatchGroup GhcRn (LHsCmd GhcRn)
matches (TcType -> ExpRhoType
mkCheckExpType TcType
res_ty)
  where
    match_ctxt :: TcMatchCtxt HsCmd
match_ctxt = MC :: forall (body :: * -> *).
HsMatchContext GhcRn
-> (Located (body GhcRn)
    -> ExpRhoType -> TcM (Located (body GhcTc)))
-> TcMatchCtxt body
MC { mc_what :: HsMatchContext GhcRn
mc_what = HsMatchContext GhcRn
forall p. HsMatchContext p
CaseAlt,
                      mc_body :: LHsCmd GhcRn -> ExpRhoType -> TcM (LHsCmd GhcTc)
mc_body = LHsCmd GhcRn -> ExpRhoType -> TcM (LHsCmd GhcTc)
mc_body }
    mc_body :: LHsCmd GhcRn -> ExpRhoType -> TcM (LHsCmd GhcTc)
mc_body LHsCmd GhcRn
body ExpRhoType
res_ty' = do { TcType
res_ty' <- ExpRhoType -> TcM TcType
expTypeToType ExpRhoType
res_ty'
                              ; CmdEnv -> LHsCmd GhcRn -> (TcType, TcType) -> TcM (LHsCmd GhcTc)
tcCmd CmdEnv
env LHsCmd GhcRn
body (TcType
stk, TcType
res_ty') }

matchExpectedCmdArgs :: Arity -> TcType -> TcM (TcCoercionN, [TcType], TcType)
matchExpectedCmdArgs :: Arity -> TcType -> TcM (TcCoercion, [TcType], TcType)
matchExpectedCmdArgs Arity
0 TcType
ty
  = (TcCoercion, [TcType], TcType)
-> TcM (TcCoercion, [TcType], TcType)
forall (m :: * -> *) a. Monad m => a -> m a
return (TcType -> TcCoercion
mkTcNomReflCo TcType
ty, [], TcType
ty)
matchExpectedCmdArgs Arity
n TcType
ty
  = do { (TcCoercion
co1, [TcType
ty1, TcType
ty2]) <- TyCon -> TcType -> TcM (TcCoercion, [TcType])
matchExpectedTyConApp TyCon
pairTyCon TcType
ty
       ; (TcCoercion
co2, [TcType]
tys, TcType
res_ty) <- Arity -> TcType -> TcM (TcCoercion, [TcType], TcType)
matchExpectedCmdArgs (Arity
nArity -> Arity -> Arity
forall a. Num a => a -> a -> a
-Arity
1) TcType
ty2
       ; (TcCoercion, [TcType], TcType)
-> TcM (TcCoercion, [TcType], TcType)
forall (m :: * -> *) a. Monad m => a -> m a
return (Role -> TyCon -> [TcCoercion] -> TcCoercion
mkTcTyConAppCo Role
Nominal TyCon
pairTyCon [TcCoercion
co1, TcCoercion
co2], TcType
ty1TcType -> [TcType] -> [TcType]
forall a. a -> [a] -> [a]
:[TcType]
tys, TcType
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 HsStmtContext GhcRn
_ (LastStmt XLastStmt GhcRn GhcRn (LHsCmd GhcRn)
x LHsCmd GhcRn
rhs Maybe Bool
noret SyntaxExpr GhcRn
_) TcType
res_ty TcType -> TcM thing
thing_inside
  = do  { LHsCmd GhcTc
rhs' <- CmdEnv -> LHsCmd GhcRn -> (TcType, TcType) -> TcM (LHsCmd GhcTc)
tcCmd CmdEnv
env LHsCmd GhcRn
rhs (TcType
unitTy, TcType
res_ty)
        ; thing
thing <- TcType -> TcM thing
thing_inside (String -> TcType
forall a. String -> a
panic String
"tcArrDoStmt")
        ; (Stmt GhcTc (LHsCmd GhcTc), thing)
-> TcM (Stmt GhcTc (LHsCmd GhcTc), thing)
forall (m :: * -> *) a. Monad m => a -> m a
return (XLastStmt GhcTc GhcTc (LHsCmd GhcTc)
-> LHsCmd GhcTc
-> Maybe Bool
-> SyntaxExpr GhcTc
-> Stmt GhcTc (LHsCmd GhcTc)
forall idL idR body.
XLastStmt idL idR body
-> body -> Maybe Bool -> SyntaxExpr idR -> StmtLR idL idR body
LastStmt XLastStmt GhcRn GhcRn (LHsCmd GhcRn)
XLastStmt GhcTc GhcTc (LHsCmd GhcTc)
x LHsCmd GhcTc
rhs' Maybe Bool
noret SyntaxExpr GhcTc
forall (p :: Pass). IsPass p => SyntaxExpr (GhcPass p)
noSyntaxExpr, thing
thing) }

tcArrDoStmt CmdEnv
env HsStmtContext GhcRn
_ (BodyStmt XBodyStmt GhcRn GhcRn (LHsCmd GhcRn)
_ LHsCmd GhcRn
rhs SyntaxExpr GhcRn
_ SyntaxExpr GhcRn
_) TcType
res_ty TcType -> TcM thing
thing_inside
  = do  { (LHsCmd GhcTc
rhs', TcType
elt_ty) <- CmdEnv -> LHsCmd GhcRn -> TcM (LHsCmd GhcTc, TcType)
tc_arr_rhs CmdEnv
env LHsCmd GhcRn
rhs
        ; thing
thing          <- TcType -> TcM thing
thing_inside TcType
res_ty
        ; (Stmt GhcTc (LHsCmd GhcTc), thing)
-> TcM (Stmt GhcTc (LHsCmd GhcTc), thing)
forall (m :: * -> *) a. Monad m => a -> m a
return (XBodyStmt GhcTc GhcTc (LHsCmd GhcTc)
-> LHsCmd GhcTc
-> SyntaxExpr GhcTc
-> SyntaxExpr GhcTc
-> Stmt GhcTc (LHsCmd GhcTc)
forall idL idR body.
XBodyStmt idL idR body
-> body -> SyntaxExpr idR -> SyntaxExpr idR -> StmtLR idL idR body
BodyStmt TcType
XBodyStmt GhcTc GhcTc (LHsCmd GhcTc)
elt_ty LHsCmd GhcTc
rhs' SyntaxExpr GhcTc
forall (p :: Pass). IsPass p => SyntaxExpr (GhcPass p)
noSyntaxExpr SyntaxExpr GhcTc
forall (p :: Pass). IsPass p => SyntaxExpr (GhcPass p)
noSyntaxExpr, thing
thing) }

tcArrDoStmt CmdEnv
env HsStmtContext GhcRn
ctxt (BindStmt XBindStmt GhcRn GhcRn (LHsCmd GhcRn)
_ LPat GhcRn
pat LHsCmd GhcRn
rhs) TcType
res_ty TcType -> TcM thing
thing_inside
  = do  { (LHsCmd GhcTc
rhs', TcType
pat_ty) <- CmdEnv -> LHsCmd GhcRn -> TcM (LHsCmd GhcTc, TcType)
tc_arr_rhs CmdEnv
env LHsCmd GhcRn
rhs
        ; (Located (Pat GhcTc)
pat', thing
thing)  <- HsMatchContext GhcRn
-> LPat GhcRn
-> Scaled TcType
-> TcM thing
-> TcM (LPat GhcTc, thing)
forall a.
HsMatchContext GhcRn
-> LPat GhcRn -> Scaled TcType -> TcM a -> TcM (LPat GhcTc, a)
tcCheckPat (HsStmtContext GhcRn -> HsMatchContext GhcRn
forall p. HsStmtContext p -> HsMatchContext p
StmtCtxt HsStmtContext GhcRn
ctxt) LPat GhcRn
pat (TcType -> Scaled TcType
forall a. a -> Scaled a
unrestricted TcType
pat_ty) (TcM thing -> TcM (LPat GhcTc, thing))
-> TcM thing -> TcM (LPat GhcTc, thing)
forall a b. (a -> b) -> a -> b
$
                            TcType -> TcM thing
thing_inside TcType
res_ty
        ; (Stmt GhcTc (LHsCmd GhcTc), thing)
-> TcM (Stmt GhcTc (LHsCmd GhcTc), thing)
forall (m :: * -> *) a. Monad m => a -> m a
return (LPat GhcTc -> LHsCmd GhcTc -> Stmt GhcTc (LHsCmd GhcTc)
forall (bodyR :: * -> *).
LPat GhcTc
-> Located (bodyR GhcTc)
-> StmtLR GhcTc GhcTc (Located (bodyR GhcTc))
mkTcBindStmt Located (Pat GhcTc)
LPat GhcTc
pat' LHsCmd GhcTc
rhs', thing
thing) }

tcArrDoStmt CmdEnv
env HsStmtContext GhcRn
ctxt (RecStmt { recS_stmts :: forall idL idR body. StmtLR idL idR body -> [LStmtLR idL idR body]
recS_stmts = [CmdLStmt 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 :: [Name]
tup_names = [Name]
[IdP GhcRn]
rec_names [Name] -> [Name] -> [Name]
forall a. [a] -> [a] -> [a]
++ (Name -> Bool) -> [Name] -> [Name]
forall a. (a -> Bool) -> [a] -> [a]
filterOut (Name -> [Name] -> Bool
forall (t :: * -> *) a. (Foldable t, Eq a) => a -> t a -> Bool
`elem` [Name]
[IdP GhcRn]
rec_names) [Name]
[IdP GhcRn]
later_names
        ; [TcType]
tup_elt_tys <- Arity -> TcType -> TcM [TcType]
newFlexiTyVarTys ([Name] -> Arity
forall (t :: * -> *) a. Foldable t => t a -> Arity
length [Name]
tup_names) TcType
liftedTypeKind
        ; let tup_ids :: [TcTyVar]
tup_ids = (Name -> TcType -> TcTyVar) -> [Name] -> [TcType] -> [TcTyVar]
forall a b c. (a -> b -> c) -> [a] -> [b] -> [c]
zipWith (\Name
n TcType
p -> HasDebugCallStack => Name -> TcType -> TcType -> TcTyVar
Name -> TcType -> TcType -> TcTyVar
mkLocalId Name
n TcType
Many TcType
p) [Name]
tup_names [TcType]
tup_elt_tys -- Many because it's a recursive definition
        ; [TcTyVar]
-> TcM (Stmt GhcTc (LHsCmd GhcTc), thing)
-> TcM (Stmt GhcTc (LHsCmd GhcTc), thing)
forall a. [TcTyVar] -> TcM a -> TcM a
tcExtendIdEnv [TcTyVar]
tup_ids (TcM (Stmt GhcTc (LHsCmd GhcTc), thing)
 -> TcM (Stmt GhcTc (LHsCmd GhcTc), thing))
-> TcM (Stmt GhcTc (LHsCmd GhcTc), thing)
-> TcM (Stmt GhcTc (LHsCmd GhcTc), thing)
forall a b. (a -> b) -> a -> b
$ do
        { ([LStmt GhcTc (LHsCmd GhcTc)]
stmts', [HsExpr GhcTc]
tup_rets)
                <- HsStmtContext GhcRn
-> TcStmtChecker HsCmd TcType
-> [CmdLStmt GhcRn]
-> TcType
-> (TcType -> TcM [HsExpr GhcTc])
-> TcM ([LStmt GhcTc (LHsCmd GhcTc)], [HsExpr GhcTc])
forall (body :: * -> *) rho_type thing.
Outputable (body GhcRn) =>
HsStmtContext GhcRn
-> TcStmtChecker body rho_type
-> [LStmt GhcRn (Located (body GhcRn))]
-> rho_type
-> (rho_type -> TcM thing)
-> TcM ([LStmt GhcTc (Located (body GhcTc))], thing)
tcStmtsAndThen HsStmtContext GhcRn
ctxt (CmdEnv -> TcStmtChecker HsCmd TcType
tcArrDoStmt CmdEnv
env) [CmdLStmt GhcRn]
stmts TcType
res_ty   ((TcType -> TcM [HsExpr GhcTc])
 -> TcM ([LStmt GhcTc (LHsCmd GhcTc)], [HsExpr GhcTc]))
-> (TcType -> TcM [HsExpr GhcTc])
-> TcM ([LStmt GhcTc (LHsCmd GhcTc)], [HsExpr GhcTc])
forall a b. (a -> b) -> a -> b
$ \ 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 [Name]
tup_names ((TcType -> ExpRhoType) -> [TcType] -> [ExpRhoType]
forall a b. (a -> b) -> [a] -> [b]
map TcType -> ExpRhoType
mkCheckExpType [TcType]
tup_elt_tys)

        ; thing
thing <- TcType -> TcM thing
thing_inside TcType
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 [RecStmt] in GHC.Hs.Expr)

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

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

        ; (Stmt GhcTc (LHsCmd GhcTc), thing)
-> TcM (Stmt GhcTc (LHsCmd GhcTc), thing)
forall (m :: * -> *) a. Monad m => a -> m a
return (StmtLR GhcTc GhcTc Any
forall bodyR. StmtLR GhcTc GhcTc bodyR
emptyRecStmtId { recS_stmts :: [LStmt GhcTc (LHsCmd GhcTc)]
recS_stmts = [LStmt GhcTc (LHsCmd GhcTc)]
stmts'
                                 , recS_later_ids :: [IdP GhcTc]
recS_later_ids = [TcTyVar]
[IdP GhcTc]
later_ids
                                 , recS_rec_ids :: [IdP GhcTc]
recS_rec_ids = [TcTyVar]
[IdP GhcTc]
rec_ids
                                 , recS_ext :: XRecStmt GhcTc GhcTc (LHsCmd GhcTc)
recS_ext = RecStmtTc
unitRecStmtTc
                                     { recS_later_rets :: [HsExpr GhcTc]
recS_later_rets = [HsExpr GhcTc]
later_rets
                                     , recS_rec_rets :: [HsExpr GhcTc]
recS_rec_rets = [HsExpr GhcTc]
rec_rets
                                     , recS_ret_ty :: TcType
recS_ret_ty = TcType
res_ty} }, thing
thing)
        }}

tcArrDoStmt CmdEnv
_ HsStmtContext GhcRn
_ Stmt GhcRn (LHsCmd GhcRn)
stmt TcType
_ TcType -> TcM thing
_
  = String -> MsgDoc -> TcM (Stmt GhcTc (LHsCmd GhcTc), thing)
forall a. HasCallStack => String -> MsgDoc -> a
pprPanic String
"tcArrDoStmt: unexpected Stmt" (Stmt GhcRn (LHsCmd GhcRn) -> MsgDoc
forall a. Outputable a => a -> MsgDoc
ppr Stmt GhcRn (LHsCmd 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 { TcType
ty <- TcType -> TcM TcType
newFlexiTyVarTy TcType
liftedTypeKind
                        ; LHsCmd GhcTc
rhs' <- CmdEnv -> LHsCmd GhcRn -> (TcType, TcType) -> TcM (LHsCmd GhcTc)
tcCmd CmdEnv
env LHsCmd GhcRn
rhs (TcType
unitTy, TcType
ty)
                        ; (LHsCmd GhcTc, TcType) -> TcM (LHsCmd GhcTc, TcType)
forall (m :: * -> *) a. Monad m => a -> m a
return (LHsCmd GhcTc
rhs', TcType
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 -> MsgDoc
cmdCtxt HsCmd GhcRn
cmd = String -> MsgDoc
text String
"In the command:" MsgDoc -> MsgDoc -> MsgDoc
<+> HsCmd GhcRn -> MsgDoc
forall a. Outputable a => a -> MsgDoc
ppr HsCmd GhcRn
cmd