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


Desugaring arrow commands
-}

{-# LANGUAGE CPP #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE ViewPatterns #-}

module DsArrows ( dsProcExpr ) where

#include "HsVersions.h"

import GhcPrelude

import Match
import DsUtils
import DsMonad

import GHC.Hs   hiding (collectPatBinders, collectPatsBinders,
                        collectLStmtsBinders, collectLStmtBinders,
                        collectStmtBinders )
import TcHsSyn
import qualified GHC.Hs.Utils as HsUtils

-- NB: The desugarer, which straddles the source and Core worlds, sometimes
--     needs to see source types (newtypes etc), and sometimes not
--     So WATCH OUT; check each use of split*Ty functions.
-- Sigh.  This is a pain.

import {-# SOURCE #-} DsExpr ( dsExpr, dsLExpr, dsLExprNoLP, dsLocalBinds,
                               dsSyntaxExpr )

import TcType
import Type ( splitPiTy )
import TcEvidence
import CoreSyn
import CoreFVs
import CoreUtils
import MkCore
import DsBinds (dsHsWrapper)

import Name
import Id
import ConLike
import TysWiredIn
import BasicTypes
import PrelNames
import Outputable
import VarSet
import SrcLoc
import ListSetOps( assocMaybe )
import Data.List
import Util
import UniqDSet

data DsCmdEnv = DsCmdEnv {
        DsCmdEnv -> CoreExpr
arr_id, DsCmdEnv -> CoreExpr
compose_id, DsCmdEnv -> CoreExpr
first_id, DsCmdEnv -> CoreExpr
app_id, DsCmdEnv -> CoreExpr
choice_id, DsCmdEnv -> CoreExpr
loop_id :: CoreExpr
    }

mkCmdEnv :: CmdSyntaxTable GhcTc -> DsM ([CoreBind], DsCmdEnv)
-- See Note [CmdSyntaxTable] in GHC.Hs.Expr
mkCmdEnv :: CmdSyntaxTable GhcTc -> DsM ([CoreBind], DsCmdEnv)
mkCmdEnv CmdSyntaxTable GhcTc
tc_meths
  = do { ([CoreBind]
meth_binds, [(Name, Id)]
prs) <- ((Name, HsExpr GhcTc)
 -> IOEnv (Env DsGblEnv DsLclEnv) (CoreBind, (Name, Id)))
-> CmdSyntaxTable GhcTc
-> IOEnv (Env DsGblEnv DsLclEnv) ([CoreBind], [(Name, Id)])
forall (m :: * -> *) a b c.
Applicative m =>
(a -> m (b, c)) -> [a] -> m ([b], [c])
mapAndUnzipM (Name, HsExpr GhcTc)
-> IOEnv (Env DsGblEnv DsLclEnv) (CoreBind, (Name, Id))
forall a.
(a, HsExpr GhcTc)
-> IOEnv (Env DsGblEnv DsLclEnv) (CoreBind, (a, Id))
mk_bind CmdSyntaxTable GhcTc
tc_meths

       -- NB: Some of these lookups might fail, but that's OK if the
       -- symbol is never used. That's why we use Maybe first and then
       -- panic. An eager panic caused trouble in typecheck/should_compile/tc192
       ; let the_arr_id :: Maybe Id
the_arr_id     = [(Name, Id)] -> Name -> Maybe Id
forall a b. Eq a => Assoc a b -> a -> Maybe b
assocMaybe [(Name, Id)]
prs Name
arrAName
             the_compose_id :: Maybe Id
the_compose_id = [(Name, Id)] -> Name -> Maybe Id
forall a b. Eq a => Assoc a b -> a -> Maybe b
assocMaybe [(Name, Id)]
prs Name
composeAName
             the_first_id :: Maybe Id
the_first_id   = [(Name, Id)] -> Name -> Maybe Id
forall a b. Eq a => Assoc a b -> a -> Maybe b
assocMaybe [(Name, Id)]
prs Name
firstAName
             the_app_id :: Maybe Id
the_app_id     = [(Name, Id)] -> Name -> Maybe Id
forall a b. Eq a => Assoc a b -> a -> Maybe b
assocMaybe [(Name, Id)]
prs Name
appAName
             the_choice_id :: Maybe Id
the_choice_id  = [(Name, Id)] -> Name -> Maybe Id
forall a b. Eq a => Assoc a b -> a -> Maybe b
assocMaybe [(Name, Id)]
prs Name
choiceAName
             the_loop_id :: Maybe Id
the_loop_id    = [(Name, Id)] -> Name -> Maybe Id
forall a b. Eq a => Assoc a b -> a -> Maybe b
assocMaybe [(Name, Id)]
prs Name
loopAName

           -- used as an argument in, e.g., do_premap
       ; Int -> Maybe Id -> DsM ()
check_lev_poly Int
3 Maybe Id
the_arr_id

           -- used as an argument in, e.g., dsCmdStmt/BodyStmt
       ; Int -> Maybe Id -> DsM ()
check_lev_poly Int
5 Maybe Id
the_compose_id

           -- used as an argument in, e.g., dsCmdStmt/BodyStmt
       ; Int -> Maybe Id -> DsM ()
check_lev_poly Int
4 Maybe Id
the_first_id

           -- the result of the_app_id is used as an argument in, e.g.,
           -- dsCmd/HsCmdArrApp/HsHigherOrderApp
       ; Int -> Maybe Id -> DsM ()
check_lev_poly Int
2 Maybe Id
the_app_id

           -- used as an argument in, e.g., HsCmdIf
       ; Int -> Maybe Id -> DsM ()
check_lev_poly Int
5 Maybe Id
the_choice_id

           -- used as an argument in, e.g., RecStmt
       ; Int -> Maybe Id -> DsM ()
check_lev_poly Int
4 Maybe Id
the_loop_id

       ; ([CoreBind], DsCmdEnv) -> DsM ([CoreBind], DsCmdEnv)
forall (m :: * -> *) a. Monad m => a -> m a
return ([CoreBind]
meth_binds, DsCmdEnv :: CoreExpr
-> CoreExpr
-> CoreExpr
-> CoreExpr
-> CoreExpr
-> CoreExpr
-> DsCmdEnv
DsCmdEnv {
               arr_id :: CoreExpr
arr_id     = Id -> CoreExpr
forall b. Id -> Expr b
Var (Maybe Id -> Name -> Id
forall a p. Outputable a => Maybe p -> a -> p
unmaybe Maybe Id
the_arr_id Name
arrAName),
               compose_id :: CoreExpr
compose_id = Id -> CoreExpr
forall b. Id -> Expr b
Var (Maybe Id -> Name -> Id
forall a p. Outputable a => Maybe p -> a -> p
unmaybe Maybe Id
the_compose_id Name
composeAName),
               first_id :: CoreExpr
first_id   = Id -> CoreExpr
forall b. Id -> Expr b
Var (Maybe Id -> Name -> Id
forall a p. Outputable a => Maybe p -> a -> p
unmaybe Maybe Id
the_first_id Name
firstAName),
               app_id :: CoreExpr
app_id     = Id -> CoreExpr
forall b. Id -> Expr b
Var (Maybe Id -> Name -> Id
forall a p. Outputable a => Maybe p -> a -> p
unmaybe Maybe Id
the_app_id Name
appAName),
               choice_id :: CoreExpr
choice_id  = Id -> CoreExpr
forall b. Id -> Expr b
Var (Maybe Id -> Name -> Id
forall a p. Outputable a => Maybe p -> a -> p
unmaybe Maybe Id
the_choice_id Name
choiceAName),
               loop_id :: CoreExpr
loop_id    = Id -> CoreExpr
forall b. Id -> Expr b
Var (Maybe Id -> Name -> Id
forall a p. Outputable a => Maybe p -> a -> p
unmaybe Maybe Id
the_loop_id Name
loopAName)
             }) }
  where
    mk_bind :: (a, HsExpr GhcTc)
-> IOEnv (Env DsGblEnv DsLclEnv) (CoreBind, (a, Id))
mk_bind (a
std_name, HsExpr GhcTc
expr)
      = do { CoreExpr
rhs <- HsExpr GhcTc -> DsM CoreExpr
dsExpr HsExpr GhcTc
expr
           ; Id
id <- Type -> DsM Id
newSysLocalDs (CoreExpr -> Type
exprType CoreExpr
rhs)
           -- no check needed; these are functions
           ; (CoreBind, (a, Id))
-> IOEnv (Env DsGblEnv DsLclEnv) (CoreBind, (a, Id))
forall (m :: * -> *) a. Monad m => a -> m a
return (Id -> CoreExpr -> CoreBind
forall b. b -> Expr b -> Bind b
NonRec Id
id CoreExpr
rhs, (a
std_name, Id
id)) }

    unmaybe :: Maybe p -> a -> p
unmaybe Maybe p
Nothing a
name = String -> SDoc -> p
forall a. HasCallStack => String -> SDoc -> a
pprPanic String
"mkCmdEnv" (String -> SDoc
text String
"Not found:" SDoc -> SDoc -> SDoc
<+> a -> SDoc
forall a. Outputable a => a -> SDoc
ppr a
name)
    unmaybe (Just p
id) a
_  = p
id

      -- returns the result type of a pi-type (that is, a forall or a function)
      -- Note that this result type may be ill-scoped.
    res_type :: Type -> Type
    res_type :: Type -> Type
res_type Type
ty = Type
res_ty
      where
        (TyCoBinder
_, Type
res_ty) = Type -> (TyCoBinder, Type)
splitPiTy Type
ty

    check_lev_poly :: Int -- arity
                   -> Maybe Id -> DsM ()
    check_lev_poly :: Int -> Maybe Id -> DsM ()
check_lev_poly Int
_     Maybe Id
Nothing = () -> DsM ()
forall (m :: * -> *) a. Monad m => a -> m a
return ()
    check_lev_poly Int
arity (Just Id
id)
      = Type -> SDoc -> DsM ()
dsNoLevPoly (Int -> (Type -> Type) -> Type -> Type
forall a. Int -> (a -> a) -> a -> a
nTimes Int
arity Type -> Type
res_type (Id -> Type
idType Id
id))
          (String -> SDoc
text String
"In the result of the function" SDoc -> SDoc -> SDoc
<+> SDoc -> SDoc
quotes (Id -> SDoc
forall a. Outputable a => a -> SDoc
ppr Id
id))


-- arr :: forall b c. (b -> c) -> a b c
do_arr :: DsCmdEnv -> Type -> Type -> CoreExpr -> CoreExpr
do_arr :: DsCmdEnv -> Type -> Type -> CoreExpr -> CoreExpr
do_arr DsCmdEnv
ids Type
b_ty Type
c_ty CoreExpr
f = CoreExpr -> [CoreExpr] -> CoreExpr
forall b. Expr b -> [Expr b] -> Expr b
mkApps (DsCmdEnv -> CoreExpr
arr_id DsCmdEnv
ids) [Type -> CoreExpr
forall b. Type -> Expr b
Type Type
b_ty, Type -> CoreExpr
forall b. Type -> Expr b
Type Type
c_ty, CoreExpr
f]

-- (>>>) :: forall b c d. a b c -> a c d -> a b d
do_compose :: DsCmdEnv -> Type -> Type -> Type ->
                CoreExpr -> CoreExpr -> CoreExpr
do_compose :: DsCmdEnv
-> Type -> Type -> Type -> CoreExpr -> CoreExpr -> CoreExpr
do_compose DsCmdEnv
ids Type
b_ty Type
c_ty Type
d_ty CoreExpr
f CoreExpr
g
  = CoreExpr -> [CoreExpr] -> CoreExpr
forall b. Expr b -> [Expr b] -> Expr b
mkApps (DsCmdEnv -> CoreExpr
compose_id DsCmdEnv
ids) [Type -> CoreExpr
forall b. Type -> Expr b
Type Type
b_ty, Type -> CoreExpr
forall b. Type -> Expr b
Type Type
c_ty, Type -> CoreExpr
forall b. Type -> Expr b
Type Type
d_ty, CoreExpr
f, CoreExpr
g]

-- first :: forall b c d. a b c -> a (b,d) (c,d)
do_first :: DsCmdEnv -> Type -> Type -> Type -> CoreExpr -> CoreExpr
do_first :: DsCmdEnv -> Type -> Type -> Type -> CoreExpr -> CoreExpr
do_first DsCmdEnv
ids Type
b_ty Type
c_ty Type
d_ty CoreExpr
f
  = CoreExpr -> [CoreExpr] -> CoreExpr
forall b. Expr b -> [Expr b] -> Expr b
mkApps (DsCmdEnv -> CoreExpr
first_id DsCmdEnv
ids) [Type -> CoreExpr
forall b. Type -> Expr b
Type Type
b_ty, Type -> CoreExpr
forall b. Type -> Expr b
Type Type
c_ty, Type -> CoreExpr
forall b. Type -> Expr b
Type Type
d_ty, CoreExpr
f]

-- app :: forall b c. a (a b c, b) c
do_app :: DsCmdEnv -> Type -> Type -> CoreExpr
do_app :: DsCmdEnv -> Type -> Type -> CoreExpr
do_app DsCmdEnv
ids Type
b_ty Type
c_ty = CoreExpr -> [CoreExpr] -> CoreExpr
forall b. Expr b -> [Expr b] -> Expr b
mkApps (DsCmdEnv -> CoreExpr
app_id DsCmdEnv
ids) [Type -> CoreExpr
forall b. Type -> Expr b
Type Type
b_ty, Type -> CoreExpr
forall b. Type -> Expr b
Type Type
c_ty]

-- (|||) :: forall b d c. a b d -> a c d -> a (Either b c) d
-- note the swapping of d and c
do_choice :: DsCmdEnv -> Type -> Type -> Type ->
                CoreExpr -> CoreExpr -> CoreExpr
do_choice :: DsCmdEnv
-> Type -> Type -> Type -> CoreExpr -> CoreExpr -> CoreExpr
do_choice DsCmdEnv
ids Type
b_ty Type
c_ty Type
d_ty CoreExpr
f CoreExpr
g
  = CoreExpr -> [CoreExpr] -> CoreExpr
forall b. Expr b -> [Expr b] -> Expr b
mkApps (DsCmdEnv -> CoreExpr
choice_id DsCmdEnv
ids) [Type -> CoreExpr
forall b. Type -> Expr b
Type Type
b_ty, Type -> CoreExpr
forall b. Type -> Expr b
Type Type
d_ty, Type -> CoreExpr
forall b. Type -> Expr b
Type Type
c_ty, CoreExpr
f, CoreExpr
g]

-- loop :: forall b d c. a (b,d) (c,d) -> a b c
-- note the swapping of d and c
do_loop :: DsCmdEnv -> Type -> Type -> Type -> CoreExpr -> CoreExpr
do_loop :: DsCmdEnv -> Type -> Type -> Type -> CoreExpr -> CoreExpr
do_loop DsCmdEnv
ids Type
b_ty Type
c_ty Type
d_ty CoreExpr
f
  = CoreExpr -> [CoreExpr] -> CoreExpr
forall b. Expr b -> [Expr b] -> Expr b
mkApps (DsCmdEnv -> CoreExpr
loop_id DsCmdEnv
ids) [Type -> CoreExpr
forall b. Type -> Expr b
Type Type
b_ty, Type -> CoreExpr
forall b. Type -> Expr b
Type Type
d_ty, Type -> CoreExpr
forall b. Type -> Expr b
Type Type
c_ty, CoreExpr
f]

-- premap :: forall b c d. (b -> c) -> a c d -> a b d
-- premap f g = arr f >>> g
do_premap :: DsCmdEnv -> Type -> Type -> Type ->
                CoreExpr -> CoreExpr -> CoreExpr
do_premap :: DsCmdEnv
-> Type -> Type -> Type -> CoreExpr -> CoreExpr -> CoreExpr
do_premap DsCmdEnv
ids Type
b_ty Type
c_ty Type
d_ty CoreExpr
f CoreExpr
g
   = DsCmdEnv
-> Type -> Type -> Type -> CoreExpr -> CoreExpr -> CoreExpr
do_compose DsCmdEnv
ids Type
b_ty Type
c_ty Type
d_ty (DsCmdEnv -> Type -> Type -> CoreExpr -> CoreExpr
do_arr DsCmdEnv
ids Type
b_ty Type
c_ty CoreExpr
f) CoreExpr
g

mkFailExpr :: HsMatchContext Id -> Type -> DsM CoreExpr
mkFailExpr :: HsMatchContext Id -> Type -> DsM CoreExpr
mkFailExpr HsMatchContext Id
ctxt Type
ty
  = Id -> Type -> SDoc -> DsM CoreExpr
mkErrorAppDs Id
pAT_ERROR_ID Type
ty (HsMatchContext Id -> SDoc
forall id. Outputable id => HsMatchContext id -> SDoc
matchContextErrString HsMatchContext Id
ctxt)

-- construct CoreExpr for \ (a :: a_ty, b :: b_ty) -> a
mkFstExpr :: Type -> Type -> DsM CoreExpr
mkFstExpr :: Type -> Type -> DsM CoreExpr
mkFstExpr Type
a_ty Type
b_ty = do
    Id
a_var <- Type -> DsM Id
newSysLocalDs Type
a_ty
    Id
b_var <- Type -> DsM Id
newSysLocalDs Type
b_ty
    Id
pair_var <- Type -> DsM Id
newSysLocalDs (Type -> Type -> Type
mkCorePairTy Type
a_ty Type
b_ty)
    CoreExpr -> DsM CoreExpr
forall (m :: * -> *) a. Monad m => a -> m a
return (Id -> CoreExpr -> CoreExpr
forall b. b -> Expr b -> Expr b
Lam Id
pair_var
               (Id -> Id -> Id -> CoreExpr -> CoreExpr
coreCasePair Id
pair_var Id
a_var Id
b_var (Id -> CoreExpr
forall b. Id -> Expr b
Var Id
a_var)))

-- construct CoreExpr for \ (a :: a_ty, b :: b_ty) -> b
mkSndExpr :: Type -> Type -> DsM CoreExpr
mkSndExpr :: Type -> Type -> DsM CoreExpr
mkSndExpr Type
a_ty Type
b_ty = do
    Id
a_var <- Type -> DsM Id
newSysLocalDs Type
a_ty
    Id
b_var <- Type -> DsM Id
newSysLocalDs Type
b_ty
    Id
pair_var <- Type -> DsM Id
newSysLocalDs (Type -> Type -> Type
mkCorePairTy Type
a_ty Type
b_ty)
    CoreExpr -> DsM CoreExpr
forall (m :: * -> *) a. Monad m => a -> m a
return (Id -> CoreExpr -> CoreExpr
forall b. b -> Expr b -> Expr b
Lam Id
pair_var
               (Id -> Id -> Id -> CoreExpr -> CoreExpr
coreCasePair Id
pair_var Id
a_var Id
b_var (Id -> CoreExpr
forall b. Id -> Expr b
Var Id
b_var)))

{-
Build case analysis of a tuple.  This cannot be done in the DsM monad,
because the list of variables is typically not yet defined.
-}

-- coreCaseTuple [u1..] v [x1..xn] body
--      = case v of v { (x1, .., xn) -> body }
-- But the matching may be nested if the tuple is very big

coreCaseTuple :: UniqSupply -> Id -> [Id] -> CoreExpr -> CoreExpr
coreCaseTuple :: UniqSupply -> Id -> [Id] -> CoreExpr -> CoreExpr
coreCaseTuple UniqSupply
uniqs Id
scrut_var [Id]
vars CoreExpr
body
  = UniqSupply -> [Id] -> CoreExpr -> Id -> CoreExpr -> CoreExpr
mkTupleCase UniqSupply
uniqs [Id]
vars CoreExpr
body Id
scrut_var (Id -> CoreExpr
forall b. Id -> Expr b
Var Id
scrut_var)

coreCasePair :: Id -> Id -> Id -> CoreExpr -> CoreExpr
coreCasePair :: Id -> Id -> Id -> CoreExpr -> CoreExpr
coreCasePair Id
scrut_var Id
var1 Id
var2 CoreExpr
body
  = CoreExpr -> Id -> Type -> [Alt Id] -> CoreExpr
forall b. Expr b -> b -> Type -> [Alt b] -> Expr b
Case (Id -> CoreExpr
forall b. Id -> Expr b
Var Id
scrut_var) Id
scrut_var (CoreExpr -> Type
exprType CoreExpr
body)
         [(DataCon -> AltCon
DataAlt (Boxity -> Int -> DataCon
tupleDataCon Boxity
Boxed Int
2), [Id
var1, Id
var2], CoreExpr
body)]

mkCorePairTy :: Type -> Type -> Type
mkCorePairTy :: Type -> Type -> Type
mkCorePairTy Type
t1 Type
t2 = [Type] -> Type
mkBoxedTupleTy [Type
t1, Type
t2]

mkCorePairExpr :: CoreExpr -> CoreExpr -> CoreExpr
mkCorePairExpr :: CoreExpr -> CoreExpr -> CoreExpr
mkCorePairExpr CoreExpr
e1 CoreExpr
e2 = [CoreExpr] -> CoreExpr
mkCoreTup [CoreExpr
e1, CoreExpr
e2]

mkCoreUnitExpr :: CoreExpr
mkCoreUnitExpr :: CoreExpr
mkCoreUnitExpr = [CoreExpr] -> CoreExpr
mkCoreTup []

{-
The input is divided into a local environment, which is a flat tuple
(unless it's too big), and a stack, which is a right-nested pair.
In general, the input has the form

        ((x1,...,xn), (s1,...(sk,())...))

where xi are the environment values, and si the ones on the stack,
with s1 being the "top", the first one to be matched with a lambda.
-}

envStackType :: [Id] -> Type -> Type
envStackType :: [Id] -> Type -> Type
envStackType [Id]
ids Type
stack_ty = Type -> Type -> Type
mkCorePairTy ([Id] -> Type
mkBigCoreVarTupTy [Id]
ids) Type
stack_ty

-- splitTypeAt n (t1,... (tn,t)...) = ([t1, ..., tn], t)
splitTypeAt :: Int -> Type -> ([Type], Type)
splitTypeAt :: Int -> Type -> ([Type], Type)
splitTypeAt Int
n Type
ty
  | Int
n Int -> Int -> Bool
forall a. Eq a => a -> a -> Bool
== Int
0 = ([], Type
ty)
  | Bool
otherwise = case Type -> [Type]
tcTyConAppArgs Type
ty of
      [Type
t, Type
ty'] -> let ([Type]
ts, Type
ty_r) = Int -> Type -> ([Type], Type)
splitTypeAt (Int
nInt -> Int -> Int
forall a. Num a => a -> a -> a
-Int
1) Type
ty' in (Type
tType -> [Type] -> [Type]
forall a. a -> [a] -> [a]
:[Type]
ts, Type
ty_r)
      [Type]
_ -> String -> SDoc -> ([Type], Type)
forall a. HasCallStack => String -> SDoc -> a
pprPanic String
"splitTypeAt" (Type -> SDoc
forall a. Outputable a => a -> SDoc
ppr Type
ty)

----------------------------------------------
--              buildEnvStack
--
--      ((x1,...,xn),stk)

buildEnvStack :: [Id] -> Id -> CoreExpr
buildEnvStack :: [Id] -> Id -> CoreExpr
buildEnvStack [Id]
env_ids Id
stack_id
  = CoreExpr -> CoreExpr -> CoreExpr
mkCorePairExpr ([Id] -> CoreExpr
mkBigCoreVarTup [Id]
env_ids) (Id -> CoreExpr
forall b. Id -> Expr b
Var Id
stack_id)

----------------------------------------------
--              matchEnvStack
--
--      \ ((x1,...,xn),stk) -> body
--      =>
--      \ pair ->
--      case pair of (tup,stk) ->
--      case tup of (x1,...,xn) ->
--      body

matchEnvStack   :: [Id]         -- x1..xn
                -> Id           -- stk
                -> CoreExpr     -- e
                -> DsM CoreExpr
matchEnvStack :: [Id] -> Id -> CoreExpr -> DsM CoreExpr
matchEnvStack [Id]
env_ids Id
stack_id CoreExpr
body = do
    UniqSupply
uniqs <- TcRnIf DsGblEnv DsLclEnv UniqSupply
forall gbl lcl. TcRnIf gbl lcl UniqSupply
newUniqueSupply
    Id
tup_var <- Type -> DsM Id
newSysLocalDs ([Id] -> Type
mkBigCoreVarTupTy [Id]
env_ids)
    let match_env :: CoreExpr
match_env = UniqSupply -> Id -> [Id] -> CoreExpr -> CoreExpr
coreCaseTuple UniqSupply
uniqs Id
tup_var [Id]
env_ids CoreExpr
body
    Id
pair_id <- Type -> DsM Id
newSysLocalDs (Type -> Type -> Type
mkCorePairTy (Id -> Type
idType Id
tup_var) (Id -> Type
idType Id
stack_id))
    CoreExpr -> DsM CoreExpr
forall (m :: * -> *) a. Monad m => a -> m a
return (Id -> CoreExpr -> CoreExpr
forall b. b -> Expr b -> Expr b
Lam Id
pair_id (Id -> Id -> Id -> CoreExpr -> CoreExpr
coreCasePair Id
pair_id Id
tup_var Id
stack_id CoreExpr
match_env))

----------------------------------------------
--              matchEnv
--
--      \ (x1,...,xn) -> body
--      =>
--      \ tup ->
--      case tup of (x1,...,xn) ->
--      body

matchEnv :: [Id]        -- x1..xn
         -> CoreExpr    -- e
         -> DsM CoreExpr
matchEnv :: [Id] -> CoreExpr -> DsM CoreExpr
matchEnv [Id]
env_ids CoreExpr
body = do
    UniqSupply
uniqs <- TcRnIf DsGblEnv DsLclEnv UniqSupply
forall gbl lcl. TcRnIf gbl lcl UniqSupply
newUniqueSupply
    Id
tup_id <- Type -> DsM Id
newSysLocalDs ([Id] -> Type
mkBigCoreVarTupTy [Id]
env_ids)
    CoreExpr -> DsM CoreExpr
forall (m :: * -> *) a. Monad m => a -> m a
return (Id -> CoreExpr -> CoreExpr
forall b. b -> Expr b -> Expr b
Lam Id
tup_id (UniqSupply -> Id -> [Id] -> CoreExpr -> CoreExpr
coreCaseTuple UniqSupply
uniqs Id
tup_id [Id]
env_ids CoreExpr
body))

----------------------------------------------
--              matchVarStack
--
--      case (x1, ...(xn, s)...) -> e
--      =>
--      case z0 of (x1,z1) ->
--      case zn-1 of (xn,s) ->
--      e
matchVarStack :: [Id] -> Id -> CoreExpr -> DsM (Id, CoreExpr)
matchVarStack :: [Id] -> Id -> CoreExpr -> DsM (Id, CoreExpr)
matchVarStack [] Id
stack_id CoreExpr
body = (Id, CoreExpr) -> DsM (Id, CoreExpr)
forall (m :: * -> *) a. Monad m => a -> m a
return (Id
stack_id, CoreExpr
body)
matchVarStack (Id
param_id:[Id]
param_ids) Id
stack_id CoreExpr
body = do
    (Id
tail_id, CoreExpr
tail_code) <- [Id] -> Id -> CoreExpr -> DsM (Id, CoreExpr)
matchVarStack [Id]
param_ids Id
stack_id CoreExpr
body
    Id
pair_id <- Type -> DsM Id
newSysLocalDs (Type -> Type -> Type
mkCorePairTy (Id -> Type
idType Id
param_id) (Id -> Type
idType Id
tail_id))
    (Id, CoreExpr) -> DsM (Id, CoreExpr)
forall (m :: * -> *) a. Monad m => a -> m a
return (Id
pair_id, Id -> Id -> Id -> CoreExpr -> CoreExpr
coreCasePair Id
pair_id Id
param_id Id
tail_id CoreExpr
tail_code)

mkHsEnvStackExpr :: [Id] -> Id -> LHsExpr GhcTc
mkHsEnvStackExpr :: [Id] -> Id -> LHsExpr GhcTc
mkHsEnvStackExpr [Id]
env_ids Id
stack_id
  = [LHsExpr GhcTc] -> LHsExpr GhcTc
forall (a :: Pass). [LHsExpr (GhcPass a)] -> LHsExpr (GhcPass a)
mkLHsTupleExpr [[IdP GhcTc] -> LHsExpr GhcTc
forall (a :: Pass). [IdP (GhcPass a)] -> LHsExpr (GhcPass a)
mkLHsVarTuple [Id]
[IdP GhcTc]
env_ids, IdP GhcTc -> LHsExpr GhcTc
forall (id :: Pass). IdP (GhcPass id) -> LHsExpr (GhcPass id)
nlHsVar Id
IdP GhcTc
stack_id]

-- Translation of arrow abstraction

-- D; xs |-a c : () --> t'      ---> c'
-- --------------------------
-- D |- proc p -> c :: a t t'   ---> premap (\ p -> ((xs),())) c'
--
--              where (xs) is the tuple of variables bound by p

dsProcExpr
        :: LPat GhcTc
        -> LHsCmdTop GhcTc
        -> DsM CoreExpr
dsProcExpr :: LPat GhcTc -> LHsCmdTop GhcTc -> DsM CoreExpr
dsProcExpr LPat GhcTc
pat (LHsCmdTop GhcTc -> Located (SrcSpanLess (LHsCmdTop GhcTc))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L SrcSpan
_ (HsCmdTop (CmdTopTc _unitTy cmd_ty ids) cmd)) = do
    ([CoreBind]
meth_binds, DsCmdEnv
meth_ids) <- CmdSyntaxTable GhcTc -> DsM ([CoreBind], DsCmdEnv)
mkCmdEnv CmdSyntaxTable GhcTc
ids
    let locals :: VarSet
locals = [Id] -> VarSet
mkVarSet (LPat GhcTc -> [Id]
collectPatBinders LPat GhcTc
pat)
    (CoreExpr
core_cmd, DIdSet
_free_vars, [Id]
env_ids)
       <- DsCmdEnv
-> VarSet
-> Type
-> Type
-> LHsCmd GhcTc
-> DsM (CoreExpr, DIdSet, [Id])
dsfixCmd DsCmdEnv
meth_ids VarSet
locals Type
unitTy Type
cmd_ty LHsCmd GhcTc
cmd
    let env_ty :: Type
env_ty = [Id] -> Type
mkBigCoreVarTupTy [Id]
env_ids
    let env_stk_ty :: Type
env_stk_ty = Type -> Type -> Type
mkCorePairTy Type
env_ty Type
unitTy
    let env_stk_expr :: CoreExpr
env_stk_expr = CoreExpr -> CoreExpr -> CoreExpr
mkCorePairExpr ([Id] -> CoreExpr
mkBigCoreVarTup [Id]
env_ids) CoreExpr
mkCoreUnitExpr
    CoreExpr
fail_expr <- HsMatchContext Id -> Type -> DsM CoreExpr
mkFailExpr HsMatchContext Id
forall id. HsMatchContext id
ProcExpr Type
env_stk_ty
    Id
var <- LPat GhcTc -> DsM Id
selectSimpleMatchVarL LPat GhcTc
pat
    CoreExpr
match_code <- CoreExpr
-> HsMatchContext Name
-> LPat GhcTc
-> CoreExpr
-> CoreExpr
-> DsM CoreExpr
matchSimply (Id -> CoreExpr
forall b. Id -> Expr b
Var Id
var) HsMatchContext Name
forall id. HsMatchContext id
ProcExpr LPat GhcTc
pat CoreExpr
env_stk_expr CoreExpr
fail_expr
    let pat_ty :: Type
pat_ty = LPat GhcTc -> Type
hsLPatType LPat GhcTc
pat
    let proc_code :: CoreExpr
proc_code = DsCmdEnv
-> Type -> Type -> Type -> CoreExpr -> CoreExpr -> CoreExpr
do_premap DsCmdEnv
meth_ids Type
pat_ty Type
env_stk_ty Type
cmd_ty
                    (Id -> CoreExpr -> CoreExpr
forall b. b -> Expr b -> Expr b
Lam Id
var CoreExpr
match_code)
                    CoreExpr
core_cmd
    CoreExpr -> DsM CoreExpr
forall (m :: * -> *) a. Monad m => a -> m a
return ([CoreBind] -> CoreExpr -> CoreExpr
forall b. [Bind b] -> Expr b -> Expr b
mkLets [CoreBind]
meth_binds CoreExpr
proc_code)
dsProcExpr LPat GhcTc
_ LHsCmdTop GhcTc
_ = String -> DsM CoreExpr
forall a. String -> a
panic String
"dsProcExpr"

{-
Translation of a command judgement of the form

        D; xs |-a c : stk --> t

to an expression e such that

        D |- e :: a (xs, stk) t
-}

dsLCmd :: DsCmdEnv -> IdSet -> Type -> Type -> LHsCmd GhcTc -> [Id]
       -> DsM (CoreExpr, DIdSet)
dsLCmd :: DsCmdEnv
-> VarSet
-> Type
-> Type
-> LHsCmd GhcTc
-> [Id]
-> DsM (CoreExpr, DIdSet)
dsLCmd DsCmdEnv
ids VarSet
local_vars Type
stk_ty Type
res_ty LHsCmd GhcTc
cmd [Id]
env_ids
  = DsCmdEnv
-> VarSet
-> Type
-> Type
-> HsCmd GhcTc
-> [Id]
-> DsM (CoreExpr, DIdSet)
dsCmd DsCmdEnv
ids VarSet
local_vars Type
stk_ty Type
res_ty (LHsCmd GhcTc -> SrcSpanLess (LHsCmd GhcTc)
forall a. HasSrcSpan a => a -> SrcSpanLess a
unLoc LHsCmd GhcTc
cmd) [Id]
env_ids

dsCmd   :: DsCmdEnv             -- arrow combinators
        -> IdSet                -- set of local vars available to this command
        -> Type                 -- type of the stack (right-nested tuple)
        -> Type                 -- return type of the command
        -> HsCmd GhcTc           -- command to desugar
        -> [Id]           -- list of vars in the input to this command
                                -- This is typically fed back,
                                -- so don't pull on it too early
        -> DsM (CoreExpr,       -- desugared expression
                DIdSet)         -- subset of local vars that occur free

-- D |- fun :: a t1 t2
-- D, xs |- arg :: t1
-- -----------------------------
-- D; xs |-a fun -< arg : stk --> t2
--
--              ---> premap (\ ((xs), _stk) -> arg) fun

dsCmd :: DsCmdEnv
-> VarSet
-> Type
-> Type
-> HsCmd GhcTc
-> [Id]
-> DsM (CoreExpr, DIdSet)
dsCmd DsCmdEnv
ids VarSet
local_vars Type
stack_ty Type
res_ty
        (HsCmdArrApp XCmdArrApp GhcTc
arrow_ty LHsExpr GhcTc
arrow LHsExpr GhcTc
arg HsArrAppType
HsFirstOrderApp Bool
_)
        [Id]
env_ids = do
    let
        (Type
a_arg_ty, Type
_res_ty') = Type -> (Type, Type)
tcSplitAppTy Type
XCmdArrApp GhcTc
arrow_ty
        (Type
_a_ty, Type
arg_ty) = Type -> (Type, Type)
tcSplitAppTy Type
a_arg_ty
    CoreExpr
core_arrow <- LHsExpr GhcTc -> DsM CoreExpr
dsLExprNoLP LHsExpr GhcTc
arrow
    CoreExpr
core_arg   <- LHsExpr GhcTc -> DsM CoreExpr
dsLExpr LHsExpr GhcTc
arg
    Id
stack_id   <- Type -> DsM Id
newSysLocalDs Type
stack_ty
    CoreExpr
core_make_arg <- [Id] -> Id -> CoreExpr -> DsM CoreExpr
matchEnvStack [Id]
env_ids Id
stack_id CoreExpr
core_arg
    (CoreExpr, DIdSet) -> DsM (CoreExpr, DIdSet)
forall (m :: * -> *) a. Monad m => a -> m a
return (DsCmdEnv
-> Type -> Type -> Type -> CoreExpr -> CoreExpr -> CoreExpr
do_premap DsCmdEnv
ids
              ([Id] -> Type -> Type
envStackType [Id]
env_ids Type
stack_ty)
              Type
arg_ty
              Type
res_ty
              CoreExpr
core_make_arg
              CoreExpr
core_arrow,
            CoreExpr -> DIdSet
exprFreeIdsDSet CoreExpr
core_arg DIdSet -> VarSet -> DIdSet
forall a b. UniqDSet a -> UniqSet b -> UniqDSet a
`uniqDSetIntersectUniqSet` VarSet
local_vars)

-- D, xs |- fun :: a t1 t2
-- D, xs |- arg :: t1
-- ------------------------------
-- D; xs |-a fun -<< arg : stk --> t2
--
--              ---> premap (\ ((xs), _stk) -> (fun, arg)) app

dsCmd DsCmdEnv
ids VarSet
local_vars Type
stack_ty Type
res_ty
        (HsCmdArrApp XCmdArrApp GhcTc
arrow_ty LHsExpr GhcTc
arrow LHsExpr GhcTc
arg HsArrAppType
HsHigherOrderApp Bool
_)
        [Id]
env_ids = do
    let
        (Type
a_arg_ty, Type
_res_ty') = Type -> (Type, Type)
tcSplitAppTy Type
XCmdArrApp GhcTc
arrow_ty
        (Type
_a_ty, Type
arg_ty) = Type -> (Type, Type)
tcSplitAppTy Type
a_arg_ty

    CoreExpr
core_arrow <- LHsExpr GhcTc -> DsM CoreExpr
dsLExpr LHsExpr GhcTc
arrow
    CoreExpr
core_arg   <- LHsExpr GhcTc -> DsM CoreExpr
dsLExpr LHsExpr GhcTc
arg
    Id
stack_id   <- Type -> DsM Id
newSysLocalDs Type
stack_ty
    CoreExpr
core_make_pair <- [Id] -> Id -> CoreExpr -> DsM CoreExpr
matchEnvStack [Id]
env_ids Id
stack_id
          (CoreExpr -> CoreExpr -> CoreExpr
mkCorePairExpr CoreExpr
core_arrow CoreExpr
core_arg)

    (CoreExpr, DIdSet) -> DsM (CoreExpr, DIdSet)
forall (m :: * -> *) a. Monad m => a -> m a
return (DsCmdEnv
-> Type -> Type -> Type -> CoreExpr -> CoreExpr -> CoreExpr
do_premap DsCmdEnv
ids
              ([Id] -> Type -> Type
envStackType [Id]
env_ids Type
stack_ty)
              (Type -> Type -> Type
mkCorePairTy Type
XCmdArrApp GhcTc
arrow_ty Type
arg_ty)
              Type
res_ty
              CoreExpr
core_make_pair
              (DsCmdEnv -> Type -> Type -> CoreExpr
do_app DsCmdEnv
ids Type
arg_ty Type
res_ty),
            ([CoreExpr] -> DIdSet
exprsFreeIdsDSet [CoreExpr
core_arrow, CoreExpr
core_arg])
              DIdSet -> VarSet -> DIdSet
forall a b. UniqDSet a -> UniqSet b -> UniqDSet a
`uniqDSetIntersectUniqSet` VarSet
local_vars)

-- D; ys |-a cmd : (t,stk) --> t'
-- D, xs |-  exp :: t
-- ------------------------
-- D; xs |-a cmd exp : stk --> t'
--
--              ---> premap (\ ((xs),stk) -> ((ys),(e,stk))) cmd

dsCmd DsCmdEnv
ids VarSet
local_vars Type
stack_ty Type
res_ty (HsCmdApp XCmdApp GhcTc
_ LHsCmd GhcTc
cmd LHsExpr GhcTc
arg) [Id]
env_ids = do
    CoreExpr
core_arg <- LHsExpr GhcTc -> DsM CoreExpr
dsLExpr LHsExpr GhcTc
arg
    let
        arg_ty :: Type
arg_ty = CoreExpr -> Type
exprType CoreExpr
core_arg
        stack_ty' :: Type
stack_ty' = Type -> Type -> Type
mkCorePairTy Type
arg_ty Type
stack_ty
    (CoreExpr
core_cmd, DIdSet
free_vars, [Id]
env_ids')
             <- DsCmdEnv
-> VarSet
-> Type
-> Type
-> LHsCmd GhcTc
-> DsM (CoreExpr, DIdSet, [Id])
dsfixCmd DsCmdEnv
ids VarSet
local_vars Type
stack_ty' Type
res_ty LHsCmd GhcTc
cmd
    Id
stack_id <- Type -> DsM Id
newSysLocalDs Type
stack_ty
    Id
arg_id <- Type -> DsM Id
newSysLocalDsNoLP Type
arg_ty
    -- push the argument expression onto the stack
    let
        stack' :: CoreExpr
stack' = CoreExpr -> CoreExpr -> CoreExpr
mkCorePairExpr (Id -> CoreExpr
forall b. Id -> Expr b
Var Id
arg_id) (Id -> CoreExpr
forall b. Id -> Expr b
Var Id
stack_id)
        core_body :: CoreExpr
core_body = Id -> CoreExpr -> CoreExpr -> CoreExpr
bindNonRec Id
arg_id CoreExpr
core_arg
                        (CoreExpr -> CoreExpr -> CoreExpr
mkCorePairExpr ([Id] -> CoreExpr
mkBigCoreVarTup [Id]
env_ids') CoreExpr
stack')

    -- match the environment and stack against the input
    CoreExpr
core_map <- [Id] -> Id -> CoreExpr -> DsM CoreExpr
matchEnvStack [Id]
env_ids Id
stack_id CoreExpr
core_body
    (CoreExpr, DIdSet) -> DsM (CoreExpr, DIdSet)
forall (m :: * -> *) a. Monad m => a -> m a
return (DsCmdEnv
-> Type -> Type -> Type -> CoreExpr -> CoreExpr -> CoreExpr
do_premap DsCmdEnv
ids
                      ([Id] -> Type -> Type
envStackType [Id]
env_ids Type
stack_ty)
                      ([Id] -> Type -> Type
envStackType [Id]
env_ids' Type
stack_ty')
                      Type
res_ty
                      CoreExpr
core_map
                      CoreExpr
core_cmd,
            DIdSet
free_vars DIdSet -> DIdSet -> DIdSet
`unionDVarSet`
              (CoreExpr -> DIdSet
exprFreeIdsDSet CoreExpr
core_arg DIdSet -> VarSet -> DIdSet
forall a b. UniqDSet a -> UniqSet b -> UniqDSet a
`uniqDSetIntersectUniqSet` VarSet
local_vars))

-- D; ys |-a cmd : stk t'
-- -----------------------------------------------
-- D; xs |-a \ p1 ... pk -> cmd : (t1,...(tk,stk)...) t'
--
--              ---> premap (\ ((xs), (p1, ... (pk,stk)...)) -> ((ys),stk)) cmd

dsCmd DsCmdEnv
ids VarSet
local_vars Type
stack_ty Type
res_ty
        (HsCmdLam XCmdLam GhcTc
_ (MG { mg_alts :: forall p body. MatchGroup p body -> Located [LMatch p body]
mg_alts
          = (Located [LMatch GhcTc (LHsCmd GhcTc)]
-> Located (SrcSpanLess (Located [LMatch GhcTc (LHsCmd GhcTc)]))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L SrcSpan
_ [dL->L _ (Match { m_pats  = pats
                       , m_grhss = GRHSs _ [dL->L _ (GRHS _ [] body)] _ })]) }))
        [Id]
env_ids = do
    let pat_vars :: VarSet
pat_vars = [Id] -> VarSet
mkVarSet ([LPat GhcTc] -> [Id]
collectPatsBinders [LPat GhcTc]
pats)
    let
        local_vars' :: VarSet
local_vars' = VarSet
pat_vars VarSet -> VarSet -> VarSet
`unionVarSet` VarSet
local_vars
        ([Type]
pat_tys, Type
stack_ty') = Int -> Type -> ([Type], Type)
splitTypeAt ([Located (Pat GhcTc)] -> Int
forall (t :: * -> *) a. Foldable t => t a -> Int
length [Located (Pat GhcTc)]
[LPat GhcTc]
pats) Type
stack_ty
    (CoreExpr
core_body, DIdSet
free_vars, [Id]
env_ids')
       <- DsCmdEnv
-> VarSet
-> Type
-> Type
-> LHsCmd GhcTc
-> DsM (CoreExpr, DIdSet, [Id])
dsfixCmd DsCmdEnv
ids VarSet
local_vars' Type
stack_ty' Type
res_ty LHsCmd GhcTc
body
    [Id]
param_ids <- (Type -> DsM Id) -> [Type] -> IOEnv (Env DsGblEnv DsLclEnv) [Id]
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
mapM Type -> DsM Id
newSysLocalDsNoLP [Type]
pat_tys
    Id
stack_id' <- Type -> DsM Id
newSysLocalDs Type
stack_ty'

    -- the expression is built from the inside out, so the actions
    -- are presented in reverse order

    let
        -- build a new environment, plus what's left of the stack
        core_expr :: CoreExpr
core_expr = [Id] -> Id -> CoreExpr
buildEnvStack [Id]
env_ids' Id
stack_id'
        in_ty :: Type
in_ty = [Id] -> Type -> Type
envStackType [Id]
env_ids Type
stack_ty
        in_ty' :: Type
in_ty' = [Id] -> Type -> Type
envStackType [Id]
env_ids' Type
stack_ty'

    CoreExpr
fail_expr <- HsMatchContext Id -> Type -> DsM CoreExpr
mkFailExpr HsMatchContext Id
forall id. HsMatchContext id
LambdaExpr Type
in_ty'
    -- match the patterns against the parameters
    CoreExpr
match_code <- [CoreExpr]
-> HsMatchContext Name
-> [LPat GhcTc]
-> CoreExpr
-> CoreExpr
-> DsM CoreExpr
matchSimplys ((Id -> CoreExpr) -> [Id] -> [CoreExpr]
forall a b. (a -> b) -> [a] -> [b]
map Id -> CoreExpr
forall b. Id -> Expr b
Var [Id]
param_ids) HsMatchContext Name
forall id. HsMatchContext id
LambdaExpr [LPat GhcTc]
pats CoreExpr
core_expr
                    CoreExpr
fail_expr
    -- match the parameters against the top of the old stack
    (Id
stack_id, CoreExpr
param_code) <- [Id] -> Id -> CoreExpr -> DsM (Id, CoreExpr)
matchVarStack [Id]
param_ids Id
stack_id' CoreExpr
match_code
    -- match the old environment and stack against the input
    CoreExpr
select_code <- [Id] -> Id -> CoreExpr -> DsM CoreExpr
matchEnvStack [Id]
env_ids Id
stack_id CoreExpr
param_code
    (CoreExpr, DIdSet) -> DsM (CoreExpr, DIdSet)
forall (m :: * -> *) a. Monad m => a -> m a
return (DsCmdEnv
-> Type -> Type -> Type -> CoreExpr -> CoreExpr -> CoreExpr
do_premap DsCmdEnv
ids Type
in_ty Type
in_ty' Type
res_ty CoreExpr
select_code CoreExpr
core_body,
            DIdSet
free_vars DIdSet -> VarSet -> DIdSet
forall a b. UniqDSet a -> UniqSet b -> UniqDSet a
`uniqDSetMinusUniqSet` VarSet
pat_vars)

dsCmd DsCmdEnv
ids VarSet
local_vars Type
stack_ty Type
res_ty (HsCmdPar XCmdPar GhcTc
_ LHsCmd GhcTc
cmd) [Id]
env_ids
  = DsCmdEnv
-> VarSet
-> Type
-> Type
-> LHsCmd GhcTc
-> [Id]
-> DsM (CoreExpr, DIdSet)
dsLCmd DsCmdEnv
ids VarSet
local_vars Type
stack_ty Type
res_ty LHsCmd GhcTc
cmd [Id]
env_ids

-- D, xs |- e :: Bool
-- D; xs1 |-a c1 : stk --> t
-- D; xs2 |-a c2 : stk --> t
-- ----------------------------------------
-- D; xs |-a if e then c1 else c2 : stk --> t
--
--              ---> premap (\ ((xs),stk) ->
--                       if e then Left ((xs1),stk) else Right ((xs2),stk))
--                     (c1 ||| c2)

dsCmd DsCmdEnv
ids VarSet
local_vars Type
stack_ty Type
res_ty (HsCmdIf XCmdIf GhcTc
_ Maybe (SyntaxExpr GhcTc)
mb_fun LHsExpr GhcTc
cond LHsCmd GhcTc
then_cmd LHsCmd GhcTc
else_cmd)
        [Id]
env_ids = do
    CoreExpr
core_cond <- LHsExpr GhcTc -> DsM CoreExpr
dsLExpr LHsExpr GhcTc
cond
    (CoreExpr
core_then, DIdSet
fvs_then, [Id]
then_ids)
       <- DsCmdEnv
-> VarSet
-> Type
-> Type
-> LHsCmd GhcTc
-> DsM (CoreExpr, DIdSet, [Id])
dsfixCmd DsCmdEnv
ids VarSet
local_vars Type
stack_ty Type
res_ty LHsCmd GhcTc
then_cmd
    (CoreExpr
core_else, DIdSet
fvs_else, [Id]
else_ids)
       <- DsCmdEnv
-> VarSet
-> Type
-> Type
-> LHsCmd GhcTc
-> DsM (CoreExpr, DIdSet, [Id])
dsfixCmd DsCmdEnv
ids VarSet
local_vars Type
stack_ty Type
res_ty LHsCmd GhcTc
else_cmd
    Id
stack_id   <- Type -> DsM Id
newSysLocalDs Type
stack_ty
    TyCon
either_con <- Name -> DsM TyCon
dsLookupTyCon Name
eitherTyConName
    DataCon
left_con   <- Name -> DsM DataCon
dsLookupDataCon Name
leftDataConName
    DataCon
right_con  <- Name -> DsM DataCon
dsLookupDataCon Name
rightDataConName

    let mk_left_expr :: Type -> Type -> CoreExpr -> CoreExpr
mk_left_expr Type
ty1 Type
ty2 CoreExpr
e = DataCon -> [CoreExpr] -> CoreExpr
mkCoreConApps DataCon
left_con   [Type -> CoreExpr
forall b. Type -> Expr b
Type Type
ty1,Type -> CoreExpr
forall b. Type -> Expr b
Type Type
ty2, CoreExpr
e]
        mk_right_expr :: Type -> Type -> CoreExpr -> CoreExpr
mk_right_expr Type
ty1 Type
ty2 CoreExpr
e = DataCon -> [CoreExpr] -> CoreExpr
mkCoreConApps DataCon
right_con [Type -> CoreExpr
forall b. Type -> Expr b
Type Type
ty1,Type -> CoreExpr
forall b. Type -> Expr b
Type Type
ty2, CoreExpr
e]

        in_ty :: Type
in_ty = [Id] -> Type -> Type
envStackType [Id]
env_ids Type
stack_ty
        then_ty :: Type
then_ty = [Id] -> Type -> Type
envStackType [Id]
then_ids Type
stack_ty
        else_ty :: Type
else_ty = [Id] -> Type -> Type
envStackType [Id]
else_ids Type
stack_ty
        sum_ty :: Type
sum_ty = TyCon -> [Type] -> Type
mkTyConApp TyCon
either_con [Type
then_ty, Type
else_ty]
        fvs_cond :: DIdSet
fvs_cond = CoreExpr -> DIdSet
exprFreeIdsDSet CoreExpr
core_cond
                   DIdSet -> VarSet -> DIdSet
forall a b. UniqDSet a -> UniqSet b -> UniqDSet a
`uniqDSetIntersectUniqSet` VarSet
local_vars

        core_left :: CoreExpr
core_left  = Type -> Type -> CoreExpr -> CoreExpr
mk_left_expr  Type
then_ty Type
else_ty
                       ([Id] -> Id -> CoreExpr
buildEnvStack [Id]
then_ids Id
stack_id)
        core_right :: CoreExpr
core_right = Type -> Type -> CoreExpr -> CoreExpr
mk_right_expr Type
then_ty Type
else_ty
                       ([Id] -> Id -> CoreExpr
buildEnvStack [Id]
else_ids Id
stack_id)

    CoreExpr
core_if <- case Maybe (SyntaxExpr GhcTc)
mb_fun of
       Just SyntaxExpr GhcTc
fun -> do { CoreExpr
fun_apps <- SyntaxExpr GhcTc -> [CoreExpr] -> DsM CoreExpr
dsSyntaxExpr SyntaxExpr GhcTc
fun
                                      [CoreExpr
core_cond, CoreExpr
core_left, CoreExpr
core_right]
                      ; [Id] -> Id -> CoreExpr -> DsM CoreExpr
matchEnvStack [Id]
env_ids Id
stack_id CoreExpr
fun_apps }
       Maybe (SyntaxExpr GhcTc)
Nothing  -> [Id] -> Id -> CoreExpr -> DsM CoreExpr
matchEnvStack [Id]
env_ids Id
stack_id (CoreExpr -> DsM CoreExpr) -> CoreExpr -> DsM CoreExpr
forall a b. (a -> b) -> a -> b
$
                   CoreExpr -> CoreExpr -> CoreExpr -> CoreExpr
mkIfThenElse CoreExpr
core_cond CoreExpr
core_left CoreExpr
core_right

    (CoreExpr, DIdSet) -> DsM (CoreExpr, DIdSet)
forall (m :: * -> *) a. Monad m => a -> m a
return (DsCmdEnv
-> Type -> Type -> Type -> CoreExpr -> CoreExpr -> CoreExpr
do_premap DsCmdEnv
ids Type
in_ty Type
sum_ty Type
res_ty
                CoreExpr
core_if
                (DsCmdEnv
-> Type -> Type -> Type -> CoreExpr -> CoreExpr -> CoreExpr
do_choice DsCmdEnv
ids Type
then_ty Type
else_ty Type
res_ty CoreExpr
core_then CoreExpr
core_else),
        DIdSet
fvs_cond DIdSet -> DIdSet -> DIdSet
`unionDVarSet` DIdSet
fvs_then DIdSet -> DIdSet -> DIdSet
`unionDVarSet` DIdSet
fvs_else)

{-
Case commands are treated in much the same way as if commands
(see above) except that there are more alternatives.  For example

        case e of { p1 -> c1; p2 -> c2; p3 -> c3 }

is translated to

        premap (\ ((xs)*ts) -> case e of
                p1 -> (Left (Left (xs1)*ts))
                p2 -> Left ((Right (xs2)*ts))
                p3 -> Right ((xs3)*ts))
        ((c1 ||| c2) ||| c3)

The idea is to extract the commands from the case, build a balanced tree
of choices, and replace the commands with expressions that build tagged
tuples, obtaining a case expression that can be desugared normally.
To build all this, we use triples describing segments of the list of
case bodies, containing the following fields:
 * a list of expressions of the form (Left|Right)* ((xs)*ts), to be put
   into the case replacing the commands
 * a sum type that is the common type of these expressions, and also the
   input type of the arrow
 * a CoreExpr for an arrow built by combining the translated command
   bodies with |||.
-}

dsCmd DsCmdEnv
ids VarSet
local_vars Type
stack_ty Type
res_ty
      (HsCmdCase XCmdCase GhcTc
_ LHsExpr GhcTc
exp (MG { mg_alts :: forall p body. MatchGroup p body -> Located [LMatch p body]
mg_alts = (Located [LMatch GhcTc (LHsCmd GhcTc)]
-> Located (SrcSpanLess (Located [LMatch GhcTc (LHsCmd GhcTc)]))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L SrcSpan
l SrcSpanLess (Located [LMatch GhcTc (LHsCmd GhcTc)])
matches)
                           , mg_ext :: forall p body. MatchGroup p body -> XMG p body
mg_ext = MatchGroupTc arg_tys _
                           , mg_origin :: forall p body. MatchGroup p body -> Origin
mg_origin = Origin
origin }))
      [Id]
env_ids = do
    Id
stack_id <- Type -> DsM Id
newSysLocalDs Type
stack_ty

    -- Extract and desugar the leaf commands in the case, building tuple
    -- expressions that will (after tagging) replace these leaves

    let
        leaves :: [(LHsCmd GhcTc, VarSet)]
leaves = (LMatch GhcTc (LHsCmd GhcTc) -> [(LHsCmd GhcTc, VarSet)])
-> [LMatch GhcTc (LHsCmd GhcTc)] -> [(LHsCmd GhcTc, VarSet)]
forall (t :: * -> *) a b. Foldable t => (a -> [b]) -> t a -> [b]
concatMap LMatch GhcTc (LHsCmd GhcTc) -> [(LHsCmd GhcTc, VarSet)]
forall (body :: * -> *).
LMatch GhcTc (Located (body GhcTc))
-> [(Located (body GhcTc), VarSet)]
leavesMatch [LMatch GhcTc (LHsCmd GhcTc)]
SrcSpanLess (Located [LMatch GhcTc (LHsCmd GhcTc)])
matches
        make_branch :: (LHsCmd GhcTc, VarSet)
-> IOEnv (Env DsGblEnv DsLclEnv) ([LHsExpr GhcTc], Type, CoreExpr)
make_branch (LHsCmd GhcTc
leaf, VarSet
bound_vars) = do
            (CoreExpr
core_leaf, DIdSet
_fvs, [Id]
leaf_ids)
               <- DsCmdEnv
-> VarSet
-> Type
-> Type
-> LHsCmd GhcTc
-> DsM (CoreExpr, DIdSet, [Id])
dsfixCmd DsCmdEnv
ids (VarSet
bound_vars VarSet -> VarSet -> VarSet
`unionVarSet` VarSet
local_vars) Type
stack_ty
                    Type
res_ty LHsCmd GhcTc
leaf
            ([LHsExpr GhcTc], Type, CoreExpr)
-> IOEnv (Env DsGblEnv DsLclEnv) ([LHsExpr GhcTc], Type, CoreExpr)
forall (m :: * -> *) a. Monad m => a -> m a
return ([[Id] -> Id -> LHsExpr GhcTc
mkHsEnvStackExpr [Id]
leaf_ids Id
stack_id],
                    [Id] -> Type -> Type
envStackType [Id]
leaf_ids Type
stack_ty,
                    CoreExpr
core_leaf)

    [([LHsExpr GhcTc], Type, CoreExpr)]
branches <- ((LHsCmd GhcTc, VarSet)
 -> IOEnv (Env DsGblEnv DsLclEnv) ([LHsExpr GhcTc], Type, CoreExpr))
-> [(LHsCmd GhcTc, VarSet)]
-> IOEnv
     (Env DsGblEnv DsLclEnv) [([LHsExpr GhcTc], Type, CoreExpr)]
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
mapM (LHsCmd GhcTc, VarSet)
-> IOEnv (Env DsGblEnv DsLclEnv) ([LHsExpr GhcTc], Type, CoreExpr)
make_branch [(LHsCmd GhcTc, VarSet)]
leaves
    TyCon
either_con <- Name -> DsM TyCon
dsLookupTyCon Name
eitherTyConName
    DataCon
left_con <- Name -> DsM DataCon
dsLookupDataCon Name
leftDataConName
    DataCon
right_con <- Name -> DsM DataCon
dsLookupDataCon Name
rightDataConName
    let
        left_id :: HsExpr GhcTc
left_id  = XConLikeOut GhcTc -> ConLike -> HsExpr GhcTc
forall p. XConLikeOut p -> ConLike -> HsExpr p
HsConLikeOut XConLikeOut GhcTc
NoExtField
noExtField (DataCon -> ConLike
RealDataCon DataCon
left_con)
        right_id :: HsExpr GhcTc
right_id = XConLikeOut GhcTc -> ConLike -> HsExpr GhcTc
forall p. XConLikeOut p -> ConLike -> HsExpr p
HsConLikeOut XConLikeOut GhcTc
NoExtField
noExtField (DataCon -> ConLike
RealDataCon DataCon
right_con)
        left_expr :: Type -> Type -> LHsExpr GhcTc -> LHsExpr GhcTc
left_expr  Type
ty1 Type
ty2 LHsExpr GhcTc
e = SrcSpanLess (LHsExpr GhcTc) -> LHsExpr GhcTc
forall a. HasSrcSpan a => SrcSpanLess a -> a
noLoc (SrcSpanLess (LHsExpr GhcTc) -> LHsExpr GhcTc)
-> SrcSpanLess (LHsExpr GhcTc) -> LHsExpr GhcTc
forall a b. (a -> b) -> a -> b
$ XApp GhcTc -> LHsExpr GhcTc -> LHsExpr GhcTc -> HsExpr GhcTc
forall p. XApp p -> LHsExpr p -> LHsExpr p -> HsExpr p
HsApp XApp GhcTc
NoExtField
noExtField
                           (SrcSpanLess (LHsExpr GhcTc) -> LHsExpr GhcTc
forall a. HasSrcSpan a => SrcSpanLess a -> a
noLoc (SrcSpanLess (LHsExpr GhcTc) -> LHsExpr GhcTc)
-> SrcSpanLess (LHsExpr GhcTc) -> LHsExpr GhcTc
forall a b. (a -> b) -> a -> b
$ HsWrapper -> HsExpr GhcTc -> HsExpr GhcTc
forall (id :: Pass).
HsWrapper -> HsExpr (GhcPass id) -> HsExpr (GhcPass id)
mkHsWrap ([Type] -> HsWrapper
mkWpTyApps [Type
ty1, Type
ty2]) HsExpr GhcTc
left_id ) LHsExpr GhcTc
e
        right_expr :: Type -> Type -> LHsExpr GhcTc -> LHsExpr GhcTc
right_expr Type
ty1 Type
ty2 LHsExpr GhcTc
e = SrcSpanLess (LHsExpr GhcTc) -> LHsExpr GhcTc
forall a. HasSrcSpan a => SrcSpanLess a -> a
noLoc (SrcSpanLess (LHsExpr GhcTc) -> LHsExpr GhcTc)
-> SrcSpanLess (LHsExpr GhcTc) -> LHsExpr GhcTc
forall a b. (a -> b) -> a -> b
$ XApp GhcTc -> LHsExpr GhcTc -> LHsExpr GhcTc -> HsExpr GhcTc
forall p. XApp p -> LHsExpr p -> LHsExpr p -> HsExpr p
HsApp XApp GhcTc
NoExtField
noExtField
                           (SrcSpanLess (LHsExpr GhcTc) -> LHsExpr GhcTc
forall a. HasSrcSpan a => SrcSpanLess a -> a
noLoc (SrcSpanLess (LHsExpr GhcTc) -> LHsExpr GhcTc)
-> SrcSpanLess (LHsExpr GhcTc) -> LHsExpr GhcTc
forall a b. (a -> b) -> a -> b
$ HsWrapper -> HsExpr GhcTc -> HsExpr GhcTc
forall (id :: Pass).
HsWrapper -> HsExpr (GhcPass id) -> HsExpr (GhcPass id)
mkHsWrap ([Type] -> HsWrapper
mkWpTyApps [Type
ty1, Type
ty2]) HsExpr GhcTc
right_id) LHsExpr GhcTc
e

        -- Prefix each tuple with a distinct series of Left's and Right's,
        -- in a balanced way, keeping track of the types.

        merge_branches :: ([LHsExpr GhcTc], Type, CoreExpr)
-> ([LHsExpr GhcTc], Type, CoreExpr)
-> ([LHsExpr GhcTc], Type, CoreExpr)
merge_branches ([LHsExpr GhcTc]
builds1, Type
in_ty1, CoreExpr
core_exp1)
                       ([LHsExpr GhcTc]
builds2, Type
in_ty2, CoreExpr
core_exp2)
          = ((LHsExpr GhcTc -> LHsExpr GhcTc)
-> [LHsExpr GhcTc] -> [LHsExpr GhcTc]
forall a b. (a -> b) -> [a] -> [b]
map (Type -> Type -> LHsExpr GhcTc -> LHsExpr GhcTc
left_expr Type
in_ty1 Type
in_ty2) [LHsExpr GhcTc]
builds1 [LHsExpr GhcTc] -> [LHsExpr GhcTc] -> [LHsExpr GhcTc]
forall a. [a] -> [a] -> [a]
++
                (LHsExpr GhcTc -> LHsExpr GhcTc)
-> [LHsExpr GhcTc] -> [LHsExpr GhcTc]
forall a b. (a -> b) -> [a] -> [b]
map (Type -> Type -> LHsExpr GhcTc -> LHsExpr GhcTc
right_expr Type
in_ty1 Type
in_ty2) [LHsExpr GhcTc]
builds2,
             TyCon -> [Type] -> Type
mkTyConApp TyCon
either_con [Type
in_ty1, Type
in_ty2],
             DsCmdEnv
-> Type -> Type -> Type -> CoreExpr -> CoreExpr -> CoreExpr
do_choice DsCmdEnv
ids Type
in_ty1 Type
in_ty2 Type
res_ty CoreExpr
core_exp1 CoreExpr
core_exp2)
        ([LHsExpr GhcTc]
leaves', Type
sum_ty, CoreExpr
core_choices) = (([LHsExpr GhcTc], Type, CoreExpr)
 -> ([LHsExpr GhcTc], Type, CoreExpr)
 -> ([LHsExpr GhcTc], Type, CoreExpr))
-> [([LHsExpr GhcTc], Type, CoreExpr)]
-> ([LHsExpr GhcTc], Type, CoreExpr)
forall a. (a -> a -> a) -> [a] -> a
foldb ([LHsExpr GhcTc], Type, CoreExpr)
-> ([LHsExpr GhcTc], Type, CoreExpr)
-> ([LHsExpr GhcTc], Type, CoreExpr)
merge_branches [([LHsExpr GhcTc], Type, CoreExpr)]
branches

        -- Replace the commands in the case with these tagged tuples,
        -- yielding a HsExpr Id we can feed to dsExpr.

        ([LHsExpr GhcTc]
_, [LMatch GhcTc (LHsExpr GhcTc)]
matches') = ([LHsExpr GhcTc]
 -> LMatch GhcTc (LHsCmd GhcTc)
 -> ([LHsExpr GhcTc], LMatch GhcTc (LHsExpr GhcTc)))
-> [LHsExpr GhcTc]
-> [LMatch GhcTc (LHsCmd GhcTc)]
-> ([LHsExpr GhcTc], [LMatch GhcTc (LHsExpr GhcTc)])
forall (t :: * -> *) a b c.
Traversable t =>
(a -> b -> (a, c)) -> a -> t b -> (a, t c)
mapAccumL (Type
-> [LHsExpr GhcTc]
-> LMatch GhcTc (LHsCmd GhcTc)
-> ([LHsExpr GhcTc], LMatch GhcTc (LHsExpr GhcTc))
forall (body' :: * -> *) (body :: * -> *).
Type
-> [Located (body' GhcTc)]
-> LMatch GhcTc (Located (body GhcTc))
-> ([Located (body' GhcTc)], LMatch GhcTc (Located (body' GhcTc)))
replaceLeavesMatch Type
res_ty) [LHsExpr GhcTc]
leaves' [LMatch GhcTc (LHsCmd GhcTc)]
SrcSpanLess (Located [LMatch GhcTc (LHsCmd GhcTc)])
matches
        in_ty :: Type
in_ty = [Id] -> Type -> Type
envStackType [Id]
env_ids Type
stack_ty

    CoreExpr
core_body <- HsExpr GhcTc -> DsM CoreExpr
dsExpr (XCase GhcTc
-> LHsExpr GhcTc
-> MatchGroup GhcTc (LHsExpr GhcTc)
-> HsExpr GhcTc
forall p.
XCase p -> LHsExpr p -> MatchGroup p (LHsExpr p) -> HsExpr p
HsCase XCase GhcTc
NoExtField
noExtField LHsExpr GhcTc
exp
                         (MG :: forall p body.
XMG p body
-> Located [LMatch p body] -> Origin -> MatchGroup p body
MG { mg_alts :: Located [LMatch GhcTc (LHsExpr GhcTc)]
mg_alts = SrcSpan
-> SrcSpanLess (Located [LMatch GhcTc (LHsExpr GhcTc)])
-> Located [LMatch GhcTc (LHsExpr GhcTc)]
forall a. HasSrcSpan a => SrcSpan -> SrcSpanLess a -> a
cL SrcSpan
l [LMatch GhcTc (LHsExpr GhcTc)]
SrcSpanLess (Located [LMatch GhcTc (LHsExpr GhcTc)])
matches'
                             , mg_ext :: XMG GhcTc (LHsExpr GhcTc)
mg_ext = [Type] -> Type -> MatchGroupTc
MatchGroupTc [Type]
arg_tys Type
sum_ty
                             , mg_origin :: Origin
mg_origin = Origin
origin }))
        -- Note that we replace the HsCase result type by sum_ty,
        -- which is the type of matches'

    CoreExpr
core_matches <- [Id] -> Id -> CoreExpr -> DsM CoreExpr
matchEnvStack [Id]
env_ids Id
stack_id CoreExpr
core_body
    (CoreExpr, DIdSet) -> DsM (CoreExpr, DIdSet)
forall (m :: * -> *) a. Monad m => a -> m a
return (DsCmdEnv
-> Type -> Type -> Type -> CoreExpr -> CoreExpr -> CoreExpr
do_premap DsCmdEnv
ids Type
in_ty Type
sum_ty Type
res_ty CoreExpr
core_matches CoreExpr
core_choices,
            CoreExpr -> DIdSet
exprFreeIdsDSet CoreExpr
core_body DIdSet -> VarSet -> DIdSet
forall a b. UniqDSet a -> UniqSet b -> UniqDSet a
`uniqDSetIntersectUniqSet` VarSet
local_vars)

-- D; ys |-a cmd : stk --> t
-- ----------------------------------
-- D; xs |-a let binds in cmd : stk --> t
--
--              ---> premap (\ ((xs),stk) -> let binds in ((ys),stk)) c

dsCmd DsCmdEnv
ids VarSet
local_vars Type
stack_ty Type
res_ty (HsCmdLet XCmdLet GhcTc
_ lbinds :: LHsLocalBinds GhcTc
lbinds@(LHsLocalBinds GhcTc -> Located (SrcSpanLess (LHsLocalBinds GhcTc))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L SrcSpan
_ SrcSpanLess (LHsLocalBinds GhcTc)
binds) LHsCmd GhcTc
body)
                                                                    [Id]
env_ids = do
    let
        defined_vars :: VarSet
defined_vars = [Id] -> VarSet
mkVarSet (HsLocalBindsLR GhcTc GhcTc -> [IdP GhcTc]
forall (idL :: Pass) (idR :: Pass).
HsLocalBindsLR (GhcPass idL) (GhcPass idR) -> [IdP (GhcPass idL)]
collectLocalBinders SrcSpanLess (LHsLocalBinds GhcTc)
HsLocalBindsLR GhcTc GhcTc
binds)
        local_vars' :: VarSet
local_vars' = VarSet
defined_vars VarSet -> VarSet -> VarSet
`unionVarSet` VarSet
local_vars

    (CoreExpr
core_body, DIdSet
_free_vars, [Id]
env_ids')
       <- DsCmdEnv
-> VarSet
-> Type
-> Type
-> LHsCmd GhcTc
-> DsM (CoreExpr, DIdSet, [Id])
dsfixCmd DsCmdEnv
ids VarSet
local_vars' Type
stack_ty Type
res_ty LHsCmd GhcTc
body
    Id
stack_id <- Type -> DsM Id
newSysLocalDs Type
stack_ty
    -- build a new environment, plus the stack, using the let bindings
    CoreExpr
core_binds <- LHsLocalBinds GhcTc -> CoreExpr -> DsM CoreExpr
dsLocalBinds LHsLocalBinds GhcTc
lbinds ([Id] -> Id -> CoreExpr
buildEnvStack [Id]
env_ids' Id
stack_id)
    -- match the old environment and stack against the input
    CoreExpr
core_map <- [Id] -> Id -> CoreExpr -> DsM CoreExpr
matchEnvStack [Id]
env_ids Id
stack_id CoreExpr
core_binds
    (CoreExpr, DIdSet) -> DsM (CoreExpr, DIdSet)
forall (m :: * -> *) a. Monad m => a -> m a
return (DsCmdEnv
-> Type -> Type -> Type -> CoreExpr -> CoreExpr -> CoreExpr
do_premap DsCmdEnv
ids
                        ([Id] -> Type -> Type
envStackType [Id]
env_ids Type
stack_ty)
                        ([Id] -> Type -> Type
envStackType [Id]
env_ids' Type
stack_ty)
                        Type
res_ty
                        CoreExpr
core_map
                        CoreExpr
core_body,
        CoreExpr -> DIdSet
exprFreeIdsDSet CoreExpr
core_binds DIdSet -> VarSet -> DIdSet
forall a b. UniqDSet a -> UniqSet b -> UniqDSet a
`uniqDSetIntersectUniqSet` VarSet
local_vars)

-- D; xs |-a ss : t
-- ----------------------------------
-- D; xs |-a do { ss } : () --> t
--
--              ---> premap (\ (env,stk) -> env) c

dsCmd DsCmdEnv
ids VarSet
local_vars Type
stack_ty Type
res_ty do_block :: HsCmd GhcTc
do_block@(HsCmdDo XCmdDo GhcTc
stmts_ty
                                               (Located [CmdLStmt GhcTc]
-> Located (SrcSpanLess (Located [CmdLStmt GhcTc]))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L SrcSpan
loc SrcSpanLess (Located [CmdLStmt GhcTc])
stmts))
                                                                   [Id]
env_ids = do
    SrcSpan -> DsM () -> DsM ()
forall a. SrcSpan -> DsM a -> DsM a
putSrcSpanDs SrcSpan
loc (DsM () -> DsM ()) -> DsM () -> DsM ()
forall a b. (a -> b) -> a -> b
$
      Type -> SDoc -> DsM ()
dsNoLevPoly Type
XCmdDo GhcTc
stmts_ty
        (String -> SDoc
text String
"In the do-command:" SDoc -> SDoc -> SDoc
<+> HsCmd GhcTc -> SDoc
forall a. Outputable a => a -> SDoc
ppr HsCmd GhcTc
do_block)
    (CoreExpr
core_stmts, DIdSet
env_ids') <- DsCmdEnv
-> VarSet
-> Type
-> [CmdLStmt GhcTc]
-> [Id]
-> DsM (CoreExpr, DIdSet)
dsCmdDo DsCmdEnv
ids VarSet
local_vars Type
res_ty [CmdLStmt GhcTc]
SrcSpanLess (Located [CmdLStmt GhcTc])
stmts [Id]
env_ids
    let env_ty :: Type
env_ty = [Id] -> Type
mkBigCoreVarTupTy [Id]
env_ids
    CoreExpr
core_fst <- Type -> Type -> DsM CoreExpr
mkFstExpr Type
env_ty Type
stack_ty
    (CoreExpr, DIdSet) -> DsM (CoreExpr, DIdSet)
forall (m :: * -> *) a. Monad m => a -> m a
return (DsCmdEnv
-> Type -> Type -> Type -> CoreExpr -> CoreExpr -> CoreExpr
do_premap DsCmdEnv
ids
                (Type -> Type -> Type
mkCorePairTy Type
env_ty Type
stack_ty)
                Type
env_ty
                Type
res_ty
                CoreExpr
core_fst
                CoreExpr
core_stmts,
        DIdSet
env_ids')

-- D |- e :: forall e. a1 (e,stk1) t1 -> ... an (e,stkn) tn -> a (e,stk) t
-- D; xs |-a ci :: stki --> ti
-- -----------------------------------
-- D; xs |-a (|e c1 ... cn|) :: stk --> t       ---> e [t_xs] c1 ... cn

dsCmd DsCmdEnv
_ VarSet
local_vars Type
_stack_ty Type
_res_ty (HsCmdArrForm XCmdArrForm GhcTc
_ LHsExpr GhcTc
op LexicalFixity
_ Maybe Fixity
_ [LHsCmdTop GhcTc]
args) [Id]
env_ids = do
    let env_ty :: Type
env_ty = [Id] -> Type
mkBigCoreVarTupTy [Id]
env_ids
    CoreExpr
core_op <- LHsExpr GhcTc -> DsM CoreExpr
dsLExpr LHsExpr GhcTc
op
    ([CoreExpr]
core_args, [DIdSet]
fv_sets) <- (LHsCmdTop GhcTc -> DsM (CoreExpr, DIdSet))
-> [LHsCmdTop GhcTc]
-> IOEnv (Env DsGblEnv DsLclEnv) ([CoreExpr], [DIdSet])
forall (m :: * -> *) a b c.
Applicative m =>
(a -> m (b, c)) -> [a] -> m ([b], [c])
mapAndUnzipM (VarSet -> [Id] -> LHsCmdTop GhcTc -> DsM (CoreExpr, DIdSet)
dsTrimCmdArg VarSet
local_vars [Id]
env_ids) [LHsCmdTop GhcTc]
args
    (CoreExpr, DIdSet) -> DsM (CoreExpr, DIdSet)
forall (m :: * -> *) a. Monad m => a -> m a
return (CoreExpr -> [CoreExpr] -> CoreExpr
forall b. Expr b -> [Expr b] -> Expr b
mkApps (CoreExpr -> CoreExpr -> CoreExpr
forall b. Expr b -> Expr b -> Expr b
App CoreExpr
core_op (Type -> CoreExpr
forall b. Type -> Expr b
Type Type
env_ty)) [CoreExpr]
core_args,
            [DIdSet] -> DIdSet
unionDVarSets [DIdSet]
fv_sets)

dsCmd DsCmdEnv
ids VarSet
local_vars Type
stack_ty Type
res_ty (HsCmdWrap XCmdWrap GhcTc
_ HsWrapper
wrap HsCmd GhcTc
cmd) [Id]
env_ids = do
    (CoreExpr
core_cmd, DIdSet
env_ids') <- DsCmdEnv
-> VarSet
-> Type
-> Type
-> HsCmd GhcTc
-> [Id]
-> DsM (CoreExpr, DIdSet)
dsCmd DsCmdEnv
ids VarSet
local_vars Type
stack_ty Type
res_ty HsCmd GhcTc
cmd [Id]
env_ids
    CoreExpr -> CoreExpr
core_wrap <- HsWrapper -> DsM (CoreExpr -> CoreExpr)
dsHsWrapper HsWrapper
wrap
    (CoreExpr, DIdSet) -> DsM (CoreExpr, DIdSet)
forall (m :: * -> *) a. Monad m => a -> m a
return (CoreExpr -> CoreExpr
core_wrap CoreExpr
core_cmd, DIdSet
env_ids')

dsCmd DsCmdEnv
_ VarSet
_ Type
_ Type
_ HsCmd GhcTc
_ [Id]
c = String -> SDoc -> DsM (CoreExpr, DIdSet)
forall a. HasCallStack => String -> SDoc -> a
pprPanic String
"dsCmd" ([Id] -> SDoc
forall a. Outputable a => a -> SDoc
ppr [Id]
c)

-- D; ys |-a c : stk --> t      (ys <= xs)
-- ---------------------
-- D; xs |-a c : stk --> t      ---> premap (\ ((xs),stk) -> ((ys),stk)) c

dsTrimCmdArg
        :: IdSet                -- set of local vars available to this command
        -> [Id]           -- list of vars in the input to this command
        -> LHsCmdTop GhcTc       -- command argument to desugar
        -> DsM (CoreExpr,       -- desugared expression
                DIdSet)         -- subset of local vars that occur free
dsTrimCmdArg :: VarSet -> [Id] -> LHsCmdTop GhcTc -> DsM (CoreExpr, DIdSet)
dsTrimCmdArg VarSet
local_vars [Id]
env_ids
                       (LHsCmdTop GhcTc -> Located (SrcSpanLess (LHsCmdTop GhcTc))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L SrcSpan
_ (HsCmdTop
                                 (CmdTopTc stack_ty cmd_ty ids) cmd )) = do
    ([CoreBind]
meth_binds, DsCmdEnv
meth_ids) <- CmdSyntaxTable GhcTc -> DsM ([CoreBind], DsCmdEnv)
mkCmdEnv CmdSyntaxTable GhcTc
ids
    (CoreExpr
core_cmd, DIdSet
free_vars, [Id]
env_ids')
       <- DsCmdEnv
-> VarSet
-> Type
-> Type
-> LHsCmd GhcTc
-> DsM (CoreExpr, DIdSet, [Id])
dsfixCmd DsCmdEnv
meth_ids VarSet
local_vars Type
stack_ty Type
cmd_ty LHsCmd GhcTc
cmd
    Id
stack_id <- Type -> DsM Id
newSysLocalDs Type
stack_ty
    CoreExpr
trim_code
      <- [Id] -> Id -> CoreExpr -> DsM CoreExpr
matchEnvStack [Id]
env_ids Id
stack_id ([Id] -> Id -> CoreExpr
buildEnvStack [Id]
env_ids' Id
stack_id)
    let
        in_ty :: Type
in_ty = [Id] -> Type -> Type
envStackType [Id]
env_ids Type
stack_ty
        in_ty' :: Type
in_ty' = [Id] -> Type -> Type
envStackType [Id]
env_ids' Type
stack_ty
        arg_code :: CoreExpr
arg_code = if [Id]
env_ids' [Id] -> [Id] -> Bool
forall a. Eq a => a -> a -> Bool
== [Id]
env_ids then CoreExpr
core_cmd else
                DsCmdEnv
-> Type -> Type -> Type -> CoreExpr -> CoreExpr -> CoreExpr
do_premap DsCmdEnv
meth_ids Type
in_ty Type
in_ty' Type
cmd_ty CoreExpr
trim_code CoreExpr
core_cmd
    (CoreExpr, DIdSet) -> DsM (CoreExpr, DIdSet)
forall (m :: * -> *) a. Monad m => a -> m a
return ([CoreBind] -> CoreExpr -> CoreExpr
forall b. [Bind b] -> Expr b -> Expr b
mkLets [CoreBind]
meth_binds CoreExpr
arg_code, DIdSet
free_vars)
dsTrimCmdArg VarSet
_ [Id]
_ LHsCmdTop GhcTc
_ = String -> DsM (CoreExpr, DIdSet)
forall a. String -> a
panic String
"dsTrimCmdArg"

-- Given D; xs |-a c : stk --> t, builds c with xs fed back.
-- Typically needs to be prefixed with arr (\(p, stk) -> ((xs),stk))

dsfixCmd
        :: DsCmdEnv             -- arrow combinators
        -> IdSet                -- set of local vars available to this command
        -> Type                 -- type of the stack (right-nested tuple)
        -> Type                 -- return type of the command
        -> LHsCmd GhcTc         -- command to desugar
        -> DsM (CoreExpr,       -- desugared expression
                DIdSet,         -- subset of local vars that occur free
                [Id])           -- the same local vars as a list, fed back
dsfixCmd :: DsCmdEnv
-> VarSet
-> Type
-> Type
-> LHsCmd GhcTc
-> DsM (CoreExpr, DIdSet, [Id])
dsfixCmd DsCmdEnv
ids VarSet
local_vars Type
stk_ty Type
cmd_ty LHsCmd GhcTc
cmd
  = do { SrcSpan -> DsM () -> DsM ()
forall a. SrcSpan -> DsM a -> DsM a
putSrcSpanDs (LHsCmd GhcTc -> SrcSpan
forall a. HasSrcSpan a => a -> SrcSpan
getLoc LHsCmd GhcTc
cmd) (DsM () -> DsM ()) -> DsM () -> DsM ()
forall a b. (a -> b) -> a -> b
$ Type -> SDoc -> DsM ()
dsNoLevPoly Type
cmd_ty
           (String -> SDoc
text String
"When desugaring the command:" SDoc -> SDoc -> SDoc
<+> LHsCmd GhcTc -> SDoc
forall a. Outputable a => a -> SDoc
ppr LHsCmd GhcTc
cmd)
       ; ([Id] -> DsM (CoreExpr, DIdSet)) -> DsM (CoreExpr, DIdSet, [Id])
trimInput (DsCmdEnv
-> VarSet
-> Type
-> Type
-> LHsCmd GhcTc
-> [Id]
-> DsM (CoreExpr, DIdSet)
dsLCmd DsCmdEnv
ids VarSet
local_vars Type
stk_ty Type
cmd_ty LHsCmd GhcTc
cmd) }

-- Feed back the list of local variables actually used a command,
-- for use as the input tuple of the generated arrow.

trimInput
        :: ([Id] -> DsM (CoreExpr, DIdSet))
        -> DsM (CoreExpr,       -- desugared expression
                DIdSet,         -- subset of local vars that occur free
                [Id])           -- same local vars as a list, fed back to
                                -- the inner function to form the tuple of
                                -- inputs to the arrow.
trimInput :: ([Id] -> DsM (CoreExpr, DIdSet)) -> DsM (CoreExpr, DIdSet, [Id])
trimInput [Id] -> DsM (CoreExpr, DIdSet)
build_arrow
  = ((CoreExpr, DIdSet, [Id]) -> DsM (CoreExpr, DIdSet, [Id]))
-> DsM (CoreExpr, DIdSet, [Id])
forall a. (a -> DsM a) -> DsM a
fixDs (\ ~(CoreExpr
_,DIdSet
_,[Id]
env_ids) -> do
        (CoreExpr
core_cmd, DIdSet
free_vars) <- [Id] -> DsM (CoreExpr, DIdSet)
build_arrow [Id]
env_ids
        (CoreExpr, DIdSet, [Id]) -> DsM (CoreExpr, DIdSet, [Id])
forall (m :: * -> *) a. Monad m => a -> m a
return (CoreExpr
core_cmd, DIdSet
free_vars, DIdSet -> [Id]
dVarSetElems DIdSet
free_vars))

{-
Translation of command judgements of the form

        D |-a do { ss } : t
-}

dsCmdDo :: DsCmdEnv             -- arrow combinators
        -> IdSet                -- set of local vars available to this statement
        -> Type                 -- return type of the statement
        -> [CmdLStmt GhcTc]     -- statements to desugar
        -> [Id]                 -- list of vars in the input to this statement
                                -- This is typically fed back,
                                -- so don't pull on it too early
        -> DsM (CoreExpr,       -- desugared expression
                DIdSet)         -- subset of local vars that occur free

dsCmdDo :: DsCmdEnv
-> VarSet
-> Type
-> [CmdLStmt GhcTc]
-> [Id]
-> DsM (CoreExpr, DIdSet)
dsCmdDo DsCmdEnv
_ VarSet
_ Type
_ [] [Id]
_ = String -> DsM (CoreExpr, DIdSet)
forall a. String -> a
panic String
"dsCmdDo"

-- D; xs |-a c : () --> t
-- --------------------------
-- D; xs |-a do { c } : t
--
--              ---> premap (\ (xs) -> ((xs), ())) c

dsCmdDo DsCmdEnv
ids VarSet
local_vars Type
res_ty [CmdLStmt GhcTc -> Located (SrcSpanLess (CmdLStmt GhcTc))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L SrcSpan
loc (LastStmt _ body _ _)] [Id]
env_ids = do
    SrcSpan -> DsM () -> DsM ()
forall a. SrcSpan -> DsM a -> DsM a
putSrcSpanDs SrcSpan
loc (DsM () -> DsM ()) -> DsM () -> DsM ()
forall a b. (a -> b) -> a -> b
$ Type -> SDoc -> DsM ()
dsNoLevPoly Type
res_ty
                         (String -> SDoc
text String
"In the command:" SDoc -> SDoc -> SDoc
<+> LHsCmd GhcTc -> SDoc
forall a. Outputable a => a -> SDoc
ppr LHsCmd GhcTc
body)
    (CoreExpr
core_body, DIdSet
env_ids') <- DsCmdEnv
-> VarSet
-> Type
-> Type
-> LHsCmd GhcTc
-> [Id]
-> DsM (CoreExpr, DIdSet)
dsLCmd DsCmdEnv
ids VarSet
local_vars Type
unitTy Type
res_ty LHsCmd GhcTc
body [Id]
env_ids
    let env_ty :: Type
env_ty = [Id] -> Type
mkBigCoreVarTupTy [Id]
env_ids
    Id
env_var <- Type -> DsM Id
newSysLocalDs Type
env_ty
    let core_map :: CoreExpr
core_map = Id -> CoreExpr -> CoreExpr
forall b. b -> Expr b -> Expr b
Lam Id
env_var (CoreExpr -> CoreExpr -> CoreExpr
mkCorePairExpr (Id -> CoreExpr
forall b. Id -> Expr b
Var Id
env_var) CoreExpr
mkCoreUnitExpr)
    (CoreExpr, DIdSet) -> DsM (CoreExpr, DIdSet)
forall (m :: * -> *) a. Monad m => a -> m a
return (DsCmdEnv
-> Type -> Type -> Type -> CoreExpr -> CoreExpr -> CoreExpr
do_premap DsCmdEnv
ids
                        Type
env_ty
                        (Type -> Type -> Type
mkCorePairTy Type
env_ty Type
unitTy)
                        Type
res_ty
                        CoreExpr
core_map
                        CoreExpr
core_body,
        DIdSet
env_ids')

dsCmdDo DsCmdEnv
ids VarSet
local_vars Type
res_ty (CmdLStmt GhcTc
stmt:[CmdLStmt GhcTc]
stmts) [Id]
env_ids = do
    let bound_vars :: VarSet
bound_vars  = [Id] -> VarSet
mkVarSet (CmdLStmt GhcTc -> [Id]
forall body. LStmt GhcTc body -> [Id]
collectLStmtBinders CmdLStmt GhcTc
stmt)
    let local_vars' :: VarSet
local_vars' = VarSet
bound_vars VarSet -> VarSet -> VarSet
`unionVarSet` VarSet
local_vars
    (CoreExpr
core_stmts, DIdSet
_, [Id]
env_ids') <- ([Id] -> DsM (CoreExpr, DIdSet)) -> DsM (CoreExpr, DIdSet, [Id])
trimInput (DsCmdEnv
-> VarSet
-> Type
-> [CmdLStmt GhcTc]
-> [Id]
-> DsM (CoreExpr, DIdSet)
dsCmdDo DsCmdEnv
ids VarSet
local_vars' Type
res_ty [CmdLStmt GhcTc]
stmts)
    (CoreExpr
core_stmt, DIdSet
fv_stmt) <- DsCmdEnv
-> VarSet
-> [Id]
-> CmdLStmt GhcTc
-> [Id]
-> DsM (CoreExpr, DIdSet)
dsCmdLStmt DsCmdEnv
ids VarSet
local_vars [Id]
env_ids' CmdLStmt GhcTc
stmt [Id]
env_ids
    (CoreExpr, DIdSet) -> DsM (CoreExpr, DIdSet)
forall (m :: * -> *) a. Monad m => a -> m a
return (DsCmdEnv
-> Type -> Type -> Type -> CoreExpr -> CoreExpr -> CoreExpr
do_compose DsCmdEnv
ids
                ([Id] -> Type
mkBigCoreVarTupTy [Id]
env_ids)
                ([Id] -> Type
mkBigCoreVarTupTy [Id]
env_ids')
                Type
res_ty
                CoreExpr
core_stmt
                CoreExpr
core_stmts,
              DIdSet
fv_stmt)

{-
A statement maps one local environment to another, and is represented
as an arrow from one tuple type to another.  A statement sequence is
translated to a composition of such arrows.
-}

dsCmdLStmt :: DsCmdEnv -> IdSet -> [Id] -> CmdLStmt GhcTc -> [Id]
           -> DsM (CoreExpr, DIdSet)
dsCmdLStmt :: DsCmdEnv
-> VarSet
-> [Id]
-> CmdLStmt GhcTc
-> [Id]
-> DsM (CoreExpr, DIdSet)
dsCmdLStmt DsCmdEnv
ids VarSet
local_vars [Id]
out_ids CmdLStmt GhcTc
cmd [Id]
env_ids
  = DsCmdEnv
-> VarSet
-> [Id]
-> CmdStmt GhcTc
-> [Id]
-> DsM (CoreExpr, DIdSet)
dsCmdStmt DsCmdEnv
ids VarSet
local_vars [Id]
out_ids (CmdLStmt GhcTc -> SrcSpanLess (CmdLStmt GhcTc)
forall a. HasSrcSpan a => a -> SrcSpanLess a
unLoc CmdLStmt GhcTc
cmd) [Id]
env_ids

dsCmdStmt
        :: DsCmdEnv             -- arrow combinators
        -> IdSet                -- set of local vars available to this statement
        -> [Id]                 -- list of vars in the output of this statement
        -> CmdStmt GhcTc        -- statement to desugar
        -> [Id]                 -- list of vars in the input to this statement
                                -- This is typically fed back,
                                -- so don't pull on it too early
        -> DsM (CoreExpr,       -- desugared expression
                DIdSet)         -- subset of local vars that occur free

-- D; xs1 |-a c : () --> t
-- D; xs' |-a do { ss } : t'
-- ------------------------------
-- D; xs  |-a do { c; ss } : t'
--
--              ---> premap (\ ((xs)) -> (((xs1),()),(xs')))
--                      (first c >>> arr snd) >>> ss

dsCmdStmt :: DsCmdEnv
-> VarSet
-> [Id]
-> CmdStmt GhcTc
-> [Id]
-> DsM (CoreExpr, DIdSet)
dsCmdStmt DsCmdEnv
ids VarSet
local_vars [Id]
out_ids (BodyStmt XBodyStmt GhcTc GhcTc (LHsCmd GhcTc)
c_ty LHsCmd GhcTc
cmd SyntaxExpr GhcTc
_ SyntaxExpr GhcTc
_) [Id]
env_ids = do
    (CoreExpr
core_cmd, DIdSet
fv_cmd, [Id]
env_ids1) <- DsCmdEnv
-> VarSet
-> Type
-> Type
-> LHsCmd GhcTc
-> DsM (CoreExpr, DIdSet, [Id])
dsfixCmd DsCmdEnv
ids VarSet
local_vars Type
unitTy Type
XBodyStmt GhcTc GhcTc (LHsCmd GhcTc)
c_ty LHsCmd GhcTc
cmd
    CoreExpr
core_mux <- [Id] -> CoreExpr -> DsM CoreExpr
matchEnv [Id]
env_ids
        (CoreExpr -> CoreExpr -> CoreExpr
mkCorePairExpr
            (CoreExpr -> CoreExpr -> CoreExpr
mkCorePairExpr ([Id] -> CoreExpr
mkBigCoreVarTup [Id]
env_ids1) CoreExpr
mkCoreUnitExpr)
            ([Id] -> CoreExpr
mkBigCoreVarTup [Id]
out_ids))
    let
        in_ty :: Type
in_ty = [Id] -> Type
mkBigCoreVarTupTy [Id]
env_ids
        in_ty1 :: Type
in_ty1 = Type -> Type -> Type
mkCorePairTy ([Id] -> Type
mkBigCoreVarTupTy [Id]
env_ids1) Type
unitTy
        out_ty :: Type
out_ty = [Id] -> Type
mkBigCoreVarTupTy [Id]
out_ids
        before_c_ty :: Type
before_c_ty = Type -> Type -> Type
mkCorePairTy Type
in_ty1 Type
out_ty
        after_c_ty :: Type
after_c_ty = Type -> Type -> Type
mkCorePairTy Type
XBodyStmt GhcTc GhcTc (LHsCmd GhcTc)
c_ty Type
out_ty
    Type -> SDoc -> DsM ()
dsNoLevPoly Type
XBodyStmt GhcTc GhcTc (LHsCmd GhcTc)
c_ty SDoc
empty -- I (Richard E, Dec '16) have no idea what to say here
    CoreExpr
snd_fn <- Type -> Type -> DsM CoreExpr
mkSndExpr Type
XBodyStmt GhcTc GhcTc (LHsCmd GhcTc)
c_ty Type
out_ty
    (CoreExpr, DIdSet) -> DsM (CoreExpr, DIdSet)
forall (m :: * -> *) a. Monad m => a -> m a
return (DsCmdEnv
-> Type -> Type -> Type -> CoreExpr -> CoreExpr -> CoreExpr
do_premap DsCmdEnv
ids Type
in_ty Type
before_c_ty Type
out_ty CoreExpr
core_mux (CoreExpr -> CoreExpr) -> CoreExpr -> CoreExpr
forall a b. (a -> b) -> a -> b
$
                DsCmdEnv
-> Type -> Type -> Type -> CoreExpr -> CoreExpr -> CoreExpr
do_compose DsCmdEnv
ids Type
before_c_ty Type
after_c_ty Type
out_ty
                        (DsCmdEnv -> Type -> Type -> Type -> CoreExpr -> CoreExpr
do_first DsCmdEnv
ids Type
in_ty1 Type
XBodyStmt GhcTc GhcTc (LHsCmd GhcTc)
c_ty Type
out_ty CoreExpr
core_cmd) (CoreExpr -> CoreExpr) -> CoreExpr -> CoreExpr
forall a b. (a -> b) -> a -> b
$
                DsCmdEnv -> Type -> Type -> CoreExpr -> CoreExpr
do_arr DsCmdEnv
ids Type
after_c_ty Type
out_ty CoreExpr
snd_fn,
              DIdSet -> [Id] -> DIdSet
extendDVarSetList DIdSet
fv_cmd [Id]
out_ids)

-- D; xs1 |-a c : () --> t
-- D; xs' |-a do { ss } : t'            xs2 = xs' - defs(p)
-- -----------------------------------
-- D; xs  |-a do { p <- c; ss } : t'
--
--              ---> premap (\ (xs) -> (((xs1),()),(xs2)))
--                      (first c >>> arr (\ (p, (xs2)) -> (xs'))) >>> ss
--
-- It would be simpler and more consistent to do this using second,
-- but that's likely to be defined in terms of first.

dsCmdStmt DsCmdEnv
ids VarSet
local_vars [Id]
out_ids (BindStmt XBindStmt GhcTc GhcTc (LHsCmd GhcTc)
_ LPat GhcTc
pat LHsCmd GhcTc
cmd SyntaxExpr GhcTc
_ SyntaxExpr GhcTc
_) [Id]
env_ids = do
    let pat_ty :: Type
pat_ty = LPat GhcTc -> Type
hsLPatType LPat GhcTc
pat
    (CoreExpr
core_cmd, DIdSet
fv_cmd, [Id]
env_ids1) <- DsCmdEnv
-> VarSet
-> Type
-> Type
-> LHsCmd GhcTc
-> DsM (CoreExpr, DIdSet, [Id])
dsfixCmd DsCmdEnv
ids VarSet
local_vars Type
unitTy Type
pat_ty LHsCmd GhcTc
cmd
    let pat_vars :: VarSet
pat_vars = [Id] -> VarSet
mkVarSet (LPat GhcTc -> [Id]
collectPatBinders LPat GhcTc
pat)
    let
        env_ids2 :: [Id]
env_ids2 = (Id -> Bool) -> [Id] -> [Id]
forall a. (a -> Bool) -> [a] -> [a]
filterOut (Id -> VarSet -> Bool
`elemVarSet` VarSet
pat_vars) [Id]
out_ids
        env_ty2 :: Type
env_ty2 = [Id] -> Type
mkBigCoreVarTupTy [Id]
env_ids2

    -- multiplexing function
    --          \ (xs) -> (((xs1),()),(xs2))

    CoreExpr
core_mux <- [Id] -> CoreExpr -> DsM CoreExpr
matchEnv [Id]
env_ids
        (CoreExpr -> CoreExpr -> CoreExpr
mkCorePairExpr
            (CoreExpr -> CoreExpr -> CoreExpr
mkCorePairExpr ([Id] -> CoreExpr
mkBigCoreVarTup [Id]
env_ids1) CoreExpr
mkCoreUnitExpr)
            ([Id] -> CoreExpr
mkBigCoreVarTup [Id]
env_ids2))

    -- projection function
    --          \ (p, (xs2)) -> (zs)

    Id
env_id <- Type -> DsM Id
newSysLocalDs Type
env_ty2
    UniqSupply
uniqs <- TcRnIf DsGblEnv DsLclEnv UniqSupply
forall gbl lcl. TcRnIf gbl lcl UniqSupply
newUniqueSupply
    let
       after_c_ty :: Type
after_c_ty = Type -> Type -> Type
mkCorePairTy Type
pat_ty Type
env_ty2
       out_ty :: Type
out_ty = [Id] -> Type
mkBigCoreVarTupTy [Id]
out_ids
       body_expr :: CoreExpr
body_expr = UniqSupply -> Id -> [Id] -> CoreExpr -> CoreExpr
coreCaseTuple UniqSupply
uniqs Id
env_id [Id]
env_ids2 ([Id] -> CoreExpr
mkBigCoreVarTup [Id]
out_ids)

    CoreExpr
fail_expr <- HsMatchContext Id -> Type -> DsM CoreExpr
mkFailExpr (HsStmtContext Id -> HsMatchContext Id
forall id. HsStmtContext id -> HsMatchContext id
StmtCtxt HsStmtContext Id
forall id. HsStmtContext id
DoExpr) Type
out_ty
    Id
pat_id    <- LPat GhcTc -> DsM Id
selectSimpleMatchVarL LPat GhcTc
pat
    CoreExpr
match_code
      <- CoreExpr
-> HsMatchContext Name
-> LPat GhcTc
-> CoreExpr
-> CoreExpr
-> DsM CoreExpr
matchSimply (Id -> CoreExpr
forall b. Id -> Expr b
Var Id
pat_id) (HsStmtContext Name -> HsMatchContext Name
forall id. HsStmtContext id -> HsMatchContext id
StmtCtxt HsStmtContext Name
forall id. HsStmtContext id
DoExpr) LPat GhcTc
pat CoreExpr
body_expr CoreExpr
fail_expr
    Id
pair_id   <- Type -> DsM Id
newSysLocalDs Type
after_c_ty
    let
        proj_expr :: CoreExpr
proj_expr = Id -> CoreExpr -> CoreExpr
forall b. b -> Expr b -> Expr b
Lam Id
pair_id (Id -> Id -> Id -> CoreExpr -> CoreExpr
coreCasePair Id
pair_id Id
pat_id Id
env_id CoreExpr
match_code)

    -- put it all together
    let
        in_ty :: Type
in_ty = [Id] -> Type
mkBigCoreVarTupTy [Id]
env_ids
        in_ty1 :: Type
in_ty1 = Type -> Type -> Type
mkCorePairTy ([Id] -> Type
mkBigCoreVarTupTy [Id]
env_ids1) Type
unitTy
        in_ty2 :: Type
in_ty2 = [Id] -> Type
mkBigCoreVarTupTy [Id]
env_ids2
        before_c_ty :: Type
before_c_ty = Type -> Type -> Type
mkCorePairTy Type
in_ty1 Type
in_ty2
    (CoreExpr, DIdSet) -> DsM (CoreExpr, DIdSet)
forall (m :: * -> *) a. Monad m => a -> m a
return (DsCmdEnv
-> Type -> Type -> Type -> CoreExpr -> CoreExpr -> CoreExpr
do_premap DsCmdEnv
ids Type
in_ty Type
before_c_ty Type
out_ty CoreExpr
core_mux (CoreExpr -> CoreExpr) -> CoreExpr -> CoreExpr
forall a b. (a -> b) -> a -> b
$
                DsCmdEnv
-> Type -> Type -> Type -> CoreExpr -> CoreExpr -> CoreExpr
do_compose DsCmdEnv
ids Type
before_c_ty Type
after_c_ty Type
out_ty
                        (DsCmdEnv -> Type -> Type -> Type -> CoreExpr -> CoreExpr
do_first DsCmdEnv
ids Type
in_ty1 Type
pat_ty Type
in_ty2 CoreExpr
core_cmd) (CoreExpr -> CoreExpr) -> CoreExpr -> CoreExpr
forall a b. (a -> b) -> a -> b
$
                DsCmdEnv -> Type -> Type -> CoreExpr -> CoreExpr
do_arr DsCmdEnv
ids Type
after_c_ty Type
out_ty CoreExpr
proj_expr,
              DIdSet
fv_cmd DIdSet -> DIdSet -> DIdSet
`unionDVarSet` ([Id] -> DIdSet
mkDVarSet [Id]
out_ids
                                     DIdSet -> VarSet -> DIdSet
forall a b. UniqDSet a -> UniqSet b -> UniqDSet a
`uniqDSetMinusUniqSet` VarSet
pat_vars))

-- D; xs' |-a do { ss } : t
-- --------------------------------------
-- D; xs  |-a do { let binds; ss } : t
--
--              ---> arr (\ (xs) -> let binds in (xs')) >>> ss

dsCmdStmt DsCmdEnv
ids VarSet
local_vars [Id]
out_ids (LetStmt XLetStmt GhcTc GhcTc (LHsCmd GhcTc)
_ LHsLocalBinds GhcTc
binds) [Id]
env_ids = do
    -- build a new environment using the let bindings
    CoreExpr
core_binds <- LHsLocalBinds GhcTc -> CoreExpr -> DsM CoreExpr
dsLocalBinds LHsLocalBinds GhcTc
binds ([Id] -> CoreExpr
mkBigCoreVarTup [Id]
out_ids)
    -- match the old environment against the input
    CoreExpr
core_map <- [Id] -> CoreExpr -> DsM CoreExpr
matchEnv [Id]
env_ids CoreExpr
core_binds
    (CoreExpr, DIdSet) -> DsM (CoreExpr, DIdSet)
forall (m :: * -> *) a. Monad m => a -> m a
return (DsCmdEnv -> Type -> Type -> CoreExpr -> CoreExpr
do_arr DsCmdEnv
ids
                        ([Id] -> Type
mkBigCoreVarTupTy [Id]
env_ids)
                        ([Id] -> Type
mkBigCoreVarTupTy [Id]
out_ids)
                        CoreExpr
core_map,
            CoreExpr -> DIdSet
exprFreeIdsDSet CoreExpr
core_binds DIdSet -> VarSet -> DIdSet
forall a b. UniqDSet a -> UniqSet b -> UniqDSet a
`uniqDSetIntersectUniqSet` VarSet
local_vars)

-- D; ys  |-a do { ss; returnA -< ((xs1), (ys2)) } : ...
-- D; xs' |-a do { ss' } : t
-- ------------------------------------
-- D; xs  |-a do { rec ss; ss' } : t
--
--                      xs1 = xs' /\ defs(ss)
--                      xs2 = xs' - defs(ss)
--                      ys1 = ys - defs(ss)
--                      ys2 = ys /\ defs(ss)
--
--              ---> arr (\(xs) -> ((ys1),(xs2))) >>>
--                      first (loop (arr (\((ys1),~(ys2)) -> (ys)) >>> ss)) >>>
--                      arr (\((xs1),(xs2)) -> (xs')) >>> ss'

dsCmdStmt DsCmdEnv
ids VarSet
local_vars [Id]
out_ids
        (RecStmt { recS_stmts :: forall idL idR body. StmtLR idL idR body -> [LStmtLR idL idR body]
recS_stmts = [CmdLStmt GhcTc]
stmts
                 , recS_later_ids :: forall idL idR body. StmtLR idL idR body -> [IdP idR]
recS_later_ids = [IdP GhcTc]
later_ids, recS_rec_ids :: forall idL idR body. StmtLR idL idR body -> [IdP idR]
recS_rec_ids = [IdP GhcTc]
rec_ids
                 , recS_ext :: forall idL idR body. StmtLR idL idR body -> XRecStmt idL idR body
recS_ext = RecStmtTc { recS_later_rets = later_rets
                                        , recS_rec_rets = rec_rets } })
        [Id]
env_ids = do
    let
        later_ids_set :: VarSet
later_ids_set = [Id] -> VarSet
mkVarSet [Id]
[IdP GhcTc]
later_ids
        env2_ids :: [Id]
env2_ids = (Id -> Bool) -> [Id] -> [Id]
forall a. (a -> Bool) -> [a] -> [a]
filterOut (Id -> VarSet -> Bool
`elemVarSet` VarSet
later_ids_set) [Id]
out_ids
        env2_id_set :: DIdSet
env2_id_set = [Id] -> DIdSet
mkDVarSet [Id]
env2_ids
        env2_ty :: Type
env2_ty = [Id] -> Type
mkBigCoreVarTupTy [Id]
env2_ids

    -- post_loop_fn = \((later_ids),(env2_ids)) -> (out_ids)

    UniqSupply
uniqs <- TcRnIf DsGblEnv DsLclEnv UniqSupply
forall gbl lcl. TcRnIf gbl lcl UniqSupply
newUniqueSupply
    Id
env2_id <- Type -> DsM Id
newSysLocalDs Type
env2_ty
    let
        later_ty :: Type
later_ty = [Id] -> Type
mkBigCoreVarTupTy [Id]
[IdP GhcTc]
later_ids
        post_pair_ty :: Type
post_pair_ty = Type -> Type -> Type
mkCorePairTy Type
later_ty Type
env2_ty
        post_loop_body :: CoreExpr
post_loop_body = UniqSupply -> Id -> [Id] -> CoreExpr -> CoreExpr
coreCaseTuple UniqSupply
uniqs Id
env2_id [Id]
env2_ids ([Id] -> CoreExpr
mkBigCoreVarTup [Id]
out_ids)

    CoreExpr
post_loop_fn <- [Id] -> Id -> CoreExpr -> DsM CoreExpr
matchEnvStack [Id]
[IdP GhcTc]
later_ids Id
env2_id CoreExpr
post_loop_body

    --- loop (...)

    (CoreExpr
core_loop, DIdSet
env1_id_set, [Id]
env1_ids)
               <- DsCmdEnv
-> VarSet
-> [CmdLStmt GhcTc]
-> [Id]
-> [HsExpr GhcTc]
-> [Id]
-> [HsExpr GhcTc]
-> DsM (CoreExpr, DIdSet, [Id])
dsRecCmd DsCmdEnv
ids VarSet
local_vars [CmdLStmt GhcTc]
stmts [Id]
[IdP GhcTc]
later_ids [HsExpr GhcTc]
later_rets [Id]
[IdP GhcTc]
rec_ids [HsExpr GhcTc]
rec_rets

    -- pre_loop_fn = \(env_ids) -> ((env1_ids),(env2_ids))

    let
        env1_ty :: Type
env1_ty = [Id] -> Type
mkBigCoreVarTupTy [Id]
env1_ids
        pre_pair_ty :: Type
pre_pair_ty = Type -> Type -> Type
mkCorePairTy Type
env1_ty Type
env2_ty
        pre_loop_body :: CoreExpr
pre_loop_body = CoreExpr -> CoreExpr -> CoreExpr
mkCorePairExpr ([Id] -> CoreExpr
mkBigCoreVarTup [Id]
env1_ids)
                                        ([Id] -> CoreExpr
mkBigCoreVarTup [Id]
env2_ids)

    CoreExpr
pre_loop_fn <- [Id] -> CoreExpr -> DsM CoreExpr
matchEnv [Id]
env_ids CoreExpr
pre_loop_body

    -- arr pre_loop_fn >>> first (loop (...)) >>> arr post_loop_fn

    let
        env_ty :: Type
env_ty = [Id] -> Type
mkBigCoreVarTupTy [Id]
env_ids
        out_ty :: Type
out_ty = [Id] -> Type
mkBigCoreVarTupTy [Id]
out_ids
        core_body :: CoreExpr
core_body = DsCmdEnv
-> Type -> Type -> Type -> CoreExpr -> CoreExpr -> CoreExpr
do_premap DsCmdEnv
ids Type
env_ty Type
pre_pair_ty Type
out_ty
                CoreExpr
pre_loop_fn
                (DsCmdEnv
-> Type -> Type -> Type -> CoreExpr -> CoreExpr -> CoreExpr
do_compose DsCmdEnv
ids Type
pre_pair_ty Type
post_pair_ty Type
out_ty
                        (DsCmdEnv -> Type -> Type -> Type -> CoreExpr -> CoreExpr
do_first DsCmdEnv
ids Type
env1_ty Type
later_ty Type
env2_ty
                                CoreExpr
core_loop)
                        (DsCmdEnv -> Type -> Type -> CoreExpr -> CoreExpr
do_arr DsCmdEnv
ids Type
post_pair_ty Type
out_ty
                                CoreExpr
post_loop_fn))

    (CoreExpr, DIdSet) -> DsM (CoreExpr, DIdSet)
forall (m :: * -> *) a. Monad m => a -> m a
return (CoreExpr
core_body, DIdSet
env1_id_set DIdSet -> DIdSet -> DIdSet
`unionDVarSet` DIdSet
env2_id_set)

dsCmdStmt DsCmdEnv
_ VarSet
_ [Id]
_ CmdStmt GhcTc
_ [Id]
s = String -> SDoc -> DsM (CoreExpr, DIdSet)
forall a. HasCallStack => String -> SDoc -> a
pprPanic String
"dsCmdStmt" ([Id] -> SDoc
forall a. Outputable a => a -> SDoc
ppr [Id]
s)

--      loop (premap (\ ((env1_ids), ~(rec_ids)) -> (env_ids))
--            (ss >>> arr (\ (out_ids) -> ((later_rets),(rec_rets))))) >>>

dsRecCmd
        :: DsCmdEnv             -- arrow combinators
        -> IdSet                -- set of local vars available to this statement
        -> [CmdLStmt GhcTc]     -- list of statements inside the RecCmd
        -> [Id]                 -- list of vars defined here and used later
        -> [HsExpr GhcTc]       -- expressions corresponding to later_ids
        -> [Id]                 -- list of vars fed back through the loop
        -> [HsExpr GhcTc]       -- expressions corresponding to rec_ids
        -> DsM (CoreExpr,       -- desugared statement
                DIdSet,         -- subset of local vars that occur free
                [Id])           -- same local vars as a list

dsRecCmd :: DsCmdEnv
-> VarSet
-> [CmdLStmt GhcTc]
-> [Id]
-> [HsExpr GhcTc]
-> [Id]
-> [HsExpr GhcTc]
-> DsM (CoreExpr, DIdSet, [Id])
dsRecCmd DsCmdEnv
ids VarSet
local_vars [CmdLStmt GhcTc]
stmts [Id]
later_ids [HsExpr GhcTc]
later_rets [Id]
rec_ids [HsExpr GhcTc]
rec_rets = do
    let
        later_id_set :: VarSet
later_id_set = [Id] -> VarSet
mkVarSet [Id]
later_ids
        rec_id_set :: VarSet
rec_id_set = [Id] -> VarSet
mkVarSet [Id]
rec_ids
        local_vars' :: VarSet
local_vars' = VarSet
rec_id_set VarSet -> VarSet -> VarSet
`unionVarSet` VarSet
later_id_set VarSet -> VarSet -> VarSet
`unionVarSet` VarSet
local_vars

    -- mk_pair_fn = \ (out_ids) -> ((later_rets),(rec_rets))

    [CoreExpr]
core_later_rets <- (HsExpr GhcTc -> DsM CoreExpr)
-> [HsExpr GhcTc] -> IOEnv (Env DsGblEnv DsLclEnv) [CoreExpr]
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
mapM HsExpr GhcTc -> DsM CoreExpr
dsExpr [HsExpr GhcTc]
later_rets
    [CoreExpr]
core_rec_rets <- (HsExpr GhcTc -> DsM CoreExpr)
-> [HsExpr GhcTc] -> IOEnv (Env DsGblEnv DsLclEnv) [CoreExpr]
forall (t :: * -> *) (m :: * -> *) a b.
(Traversable t, Monad m) =>
(a -> m b) -> t a -> m (t b)
mapM HsExpr GhcTc -> DsM CoreExpr
dsExpr [HsExpr GhcTc]
rec_rets
    let
        -- possibly polymorphic version of vars of later_ids and rec_ids
        out_ids :: [Id]
out_ids = [CoreExpr] -> [Id]
exprsFreeIdsList ([CoreExpr]
core_later_rets [CoreExpr] -> [CoreExpr] -> [CoreExpr]
forall a. [a] -> [a] -> [a]
++ [CoreExpr]
core_rec_rets)
        out_ty :: Type
out_ty = [Id] -> Type
mkBigCoreVarTupTy [Id]
out_ids

        later_tuple :: CoreExpr
later_tuple = [CoreExpr] -> CoreExpr
mkBigCoreTup [CoreExpr]
core_later_rets
        later_ty :: Type
later_ty = [Id] -> Type
mkBigCoreVarTupTy [Id]
later_ids

        rec_tuple :: CoreExpr
rec_tuple = [CoreExpr] -> CoreExpr
mkBigCoreTup [CoreExpr]
core_rec_rets
        rec_ty :: Type
rec_ty = [Id] -> Type
mkBigCoreVarTupTy [Id]
rec_ids

        out_pair :: CoreExpr
out_pair = CoreExpr -> CoreExpr -> CoreExpr
mkCorePairExpr CoreExpr
later_tuple CoreExpr
rec_tuple
        out_pair_ty :: Type
out_pair_ty = Type -> Type -> Type
mkCorePairTy Type
later_ty Type
rec_ty

    CoreExpr
mk_pair_fn <- [Id] -> CoreExpr -> DsM CoreExpr
matchEnv [Id]
out_ids CoreExpr
out_pair

    -- ss

    (CoreExpr
core_stmts, DIdSet
fv_stmts, [Id]
env_ids) <- DsCmdEnv
-> VarSet
-> [Id]
-> [CmdLStmt GhcTc]
-> DsM (CoreExpr, DIdSet, [Id])
dsfixCmdStmts DsCmdEnv
ids VarSet
local_vars' [Id]
out_ids [CmdLStmt GhcTc]
stmts

    -- squash_pair_fn = \ ((env1_ids), ~(rec_ids)) -> (env_ids)

    Id
rec_id <- Type -> DsM Id
newSysLocalDs Type
rec_ty
    let
        env1_id_set :: DIdSet
env1_id_set = DIdSet
fv_stmts DIdSet -> VarSet -> DIdSet
forall a b. UniqDSet a -> UniqSet b -> UniqDSet a
`uniqDSetMinusUniqSet` VarSet
rec_id_set
        env1_ids :: [Id]
env1_ids = DIdSet -> [Id]
dVarSetElems DIdSet
env1_id_set
        env1_ty :: Type
env1_ty = [Id] -> Type
mkBigCoreVarTupTy [Id]
env1_ids
        in_pair_ty :: Type
in_pair_ty = Type -> Type -> Type
mkCorePairTy Type
env1_ty Type
rec_ty
        core_body :: CoreExpr
core_body = [CoreExpr] -> CoreExpr
mkBigCoreTup ((Id -> CoreExpr) -> [Id] -> [CoreExpr]
forall a b. (a -> b) -> [a] -> [b]
map Id -> CoreExpr
selectVar [Id]
env_ids)
          where
            selectVar :: Id -> CoreExpr
selectVar Id
v
                | Id
v Id -> VarSet -> Bool
`elemVarSet` VarSet
rec_id_set
                  = [Id] -> Id -> Id -> CoreExpr -> CoreExpr
mkTupleSelector [Id]
rec_ids Id
v Id
rec_id (Id -> CoreExpr
forall b. Id -> Expr b
Var Id
rec_id)
                | Bool
otherwise = Id -> CoreExpr
forall b. Id -> Expr b
Var Id
v

    CoreExpr
squash_pair_fn <- [Id] -> Id -> CoreExpr -> DsM CoreExpr
matchEnvStack [Id]
env1_ids Id
rec_id CoreExpr
core_body

    -- loop (premap squash_pair_fn (ss >>> arr mk_pair_fn))

    let
        env_ty :: Type
env_ty = [Id] -> Type
mkBigCoreVarTupTy [Id]
env_ids
        core_loop :: CoreExpr
core_loop = DsCmdEnv -> Type -> Type -> Type -> CoreExpr -> CoreExpr
do_loop DsCmdEnv
ids Type
env1_ty Type
later_ty Type
rec_ty
                (DsCmdEnv
-> Type -> Type -> Type -> CoreExpr -> CoreExpr -> CoreExpr
do_premap DsCmdEnv
ids Type
in_pair_ty Type
env_ty Type
out_pair_ty
                        CoreExpr
squash_pair_fn
                        (DsCmdEnv
-> Type -> Type -> Type -> CoreExpr -> CoreExpr -> CoreExpr
do_compose DsCmdEnv
ids Type
env_ty Type
out_ty Type
out_pair_ty
                                CoreExpr
core_stmts
                                (DsCmdEnv -> Type -> Type -> CoreExpr -> CoreExpr
do_arr DsCmdEnv
ids Type
out_ty Type
out_pair_ty CoreExpr
mk_pair_fn)))

    (CoreExpr, DIdSet, [Id]) -> DsM (CoreExpr, DIdSet, [Id])
forall (m :: * -> *) a. Monad m => a -> m a
return (CoreExpr
core_loop, DIdSet
env1_id_set, [Id]
env1_ids)

{-
A sequence of statements (as in a rec) is desugared to an arrow between
two environments (no stack)
-}

dsfixCmdStmts
        :: DsCmdEnv             -- arrow combinators
        -> IdSet                -- set of local vars available to this statement
        -> [Id]                 -- output vars of these statements
        -> [CmdLStmt GhcTc]     -- statements to desugar
        -> DsM (CoreExpr,       -- desugared expression
                DIdSet,         -- subset of local vars that occur free
                [Id])           -- same local vars as a list

dsfixCmdStmts :: DsCmdEnv
-> VarSet
-> [Id]
-> [CmdLStmt GhcTc]
-> DsM (CoreExpr, DIdSet, [Id])
dsfixCmdStmts DsCmdEnv
ids VarSet
local_vars [Id]
out_ids [CmdLStmt GhcTc]
stmts
  = ([Id] -> DsM (CoreExpr, DIdSet)) -> DsM (CoreExpr, DIdSet, [Id])
trimInput (DsCmdEnv
-> VarSet
-> [Id]
-> [CmdLStmt GhcTc]
-> [Id]
-> DsM (CoreExpr, DIdSet)
dsCmdStmts DsCmdEnv
ids VarSet
local_vars [Id]
out_ids [CmdLStmt GhcTc]
stmts)
   -- TODO: Add levity polymorphism check for the resulting expression.
   -- But I (Richard E.) don't know enough about arrows to do so.

dsCmdStmts
        :: DsCmdEnv             -- arrow combinators
        -> IdSet                -- set of local vars available to this statement
        -> [Id]                 -- output vars of these statements
        -> [CmdLStmt GhcTc]     -- statements to desugar
        -> [Id]                 -- list of vars in the input to these statements
        -> DsM (CoreExpr,       -- desugared expression
                DIdSet)         -- subset of local vars that occur free

dsCmdStmts :: DsCmdEnv
-> VarSet
-> [Id]
-> [CmdLStmt GhcTc]
-> [Id]
-> DsM (CoreExpr, DIdSet)
dsCmdStmts DsCmdEnv
ids VarSet
local_vars [Id]
out_ids [CmdLStmt GhcTc
stmt] [Id]
env_ids
  = DsCmdEnv
-> VarSet
-> [Id]
-> CmdLStmt GhcTc
-> [Id]
-> DsM (CoreExpr, DIdSet)
dsCmdLStmt DsCmdEnv
ids VarSet
local_vars [Id]
out_ids CmdLStmt GhcTc
stmt [Id]
env_ids

dsCmdStmts DsCmdEnv
ids VarSet
local_vars [Id]
out_ids (CmdLStmt GhcTc
stmt:[CmdLStmt GhcTc]
stmts) [Id]
env_ids = do
    let bound_vars :: VarSet
bound_vars  = [Id] -> VarSet
mkVarSet (CmdLStmt GhcTc -> [Id]
forall body. LStmt GhcTc body -> [Id]
collectLStmtBinders CmdLStmt GhcTc
stmt)
    let local_vars' :: VarSet
local_vars' = VarSet
bound_vars VarSet -> VarSet -> VarSet
`unionVarSet` VarSet
local_vars
    (CoreExpr
core_stmts, DIdSet
_fv_stmts, [Id]
env_ids') <- DsCmdEnv
-> VarSet
-> [Id]
-> [CmdLStmt GhcTc]
-> DsM (CoreExpr, DIdSet, [Id])
dsfixCmdStmts DsCmdEnv
ids VarSet
local_vars' [Id]
out_ids [CmdLStmt GhcTc]
stmts
    (CoreExpr
core_stmt, DIdSet
fv_stmt) <- DsCmdEnv
-> VarSet
-> [Id]
-> CmdLStmt GhcTc
-> [Id]
-> DsM (CoreExpr, DIdSet)
dsCmdLStmt DsCmdEnv
ids VarSet
local_vars [Id]
env_ids' CmdLStmt GhcTc
stmt [Id]
env_ids
    (CoreExpr, DIdSet) -> DsM (CoreExpr, DIdSet)
forall (m :: * -> *) a. Monad m => a -> m a
return (DsCmdEnv
-> Type -> Type -> Type -> CoreExpr -> CoreExpr -> CoreExpr
do_compose DsCmdEnv
ids
                ([Id] -> Type
mkBigCoreVarTupTy [Id]
env_ids)
                ([Id] -> Type
mkBigCoreVarTupTy [Id]
env_ids')
                ([Id] -> Type
mkBigCoreVarTupTy [Id]
out_ids)
                CoreExpr
core_stmt
                CoreExpr
core_stmts,
              DIdSet
fv_stmt)

dsCmdStmts DsCmdEnv
_ VarSet
_ [Id]
_ [] [Id]
_ = String -> DsM (CoreExpr, DIdSet)
forall a. String -> a
panic String
"dsCmdStmts []"

-- Match a list of expressions against a list of patterns, left-to-right.

matchSimplys :: [CoreExpr]              -- Scrutinees
             -> HsMatchContext Name     -- Match kind
             -> [LPat GhcTc]            -- Patterns they should match
             -> CoreExpr                -- Return this if they all match
             -> CoreExpr                -- Return this if they don't
             -> DsM CoreExpr
matchSimplys :: [CoreExpr]
-> HsMatchContext Name
-> [LPat GhcTc]
-> CoreExpr
-> CoreExpr
-> DsM CoreExpr
matchSimplys [] HsMatchContext Name
_ctxt [] CoreExpr
result_expr CoreExpr
_fail_expr = CoreExpr -> DsM CoreExpr
forall (m :: * -> *) a. Monad m => a -> m a
return CoreExpr
result_expr
matchSimplys (CoreExpr
exp:[CoreExpr]
exps) HsMatchContext Name
ctxt (LPat GhcTc
pat:[LPat GhcTc]
pats) CoreExpr
result_expr CoreExpr
fail_expr = do
    CoreExpr
match_code <- [CoreExpr]
-> HsMatchContext Name
-> [LPat GhcTc]
-> CoreExpr
-> CoreExpr
-> DsM CoreExpr
matchSimplys [CoreExpr]
exps HsMatchContext Name
ctxt [LPat GhcTc]
pats CoreExpr
result_expr CoreExpr
fail_expr
    CoreExpr
-> HsMatchContext Name
-> LPat GhcTc
-> CoreExpr
-> CoreExpr
-> DsM CoreExpr
matchSimply CoreExpr
exp HsMatchContext Name
ctxt LPat GhcTc
pat CoreExpr
match_code CoreExpr
fail_expr
matchSimplys [CoreExpr]
_ HsMatchContext Name
_ [LPat GhcTc]
_ CoreExpr
_ CoreExpr
_ = String -> DsM CoreExpr
forall a. String -> a
panic String
"matchSimplys"

-- List of leaf expressions, with set of variables bound in each

leavesMatch :: LMatch GhcTc (Located (body GhcTc))
            -> [(Located (body GhcTc), IdSet)]
leavesMatch :: LMatch GhcTc (Located (body GhcTc))
-> [(Located (body GhcTc), VarSet)]
leavesMatch (LMatch GhcTc (Located (body GhcTc))
-> Located (SrcSpanLess (LMatch GhcTc (Located (body GhcTc))))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L SrcSpan
_ (Match { m_pats = pats
                            , m_grhss = GRHSs _ grhss (dL->L _ binds) }))
  = let
        defined_vars :: VarSet
defined_vars = [Id] -> VarSet
mkVarSet ([LPat GhcTc] -> [Id]
collectPatsBinders [LPat GhcTc]
pats)
                        VarSet -> VarSet -> VarSet
`unionVarSet`
                       [Id] -> VarSet
mkVarSet (HsLocalBindsLR GhcTc GhcTc -> [IdP GhcTc]
forall (idL :: Pass) (idR :: Pass).
HsLocalBindsLR (GhcPass idL) (GhcPass idR) -> [IdP (GhcPass idL)]
collectLocalBinders SrcSpanLess (LHsLocalBinds GhcTc)
HsLocalBindsLR GhcTc GhcTc
binds)
    in
    [(Located (body GhcTc)
body,
      [Id] -> VarSet
mkVarSet ([LStmt GhcTc (LHsExpr GhcTc)] -> [Id]
forall body. [LStmt GhcTc body] -> [Id]
collectLStmtsBinders [LStmt GhcTc (LHsExpr GhcTc)]
stmts)
        VarSet -> VarSet -> VarSet
`unionVarSet` VarSet
defined_vars)
    | (LGRHS GhcTc (Located (body GhcTc))
-> Located (SrcSpanLess (LGRHS GhcTc (Located (body GhcTc))))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L SrcSpan
_ (GRHS _ stmts body)) <- [LGRHS GhcTc (Located (body GhcTc))]
grhss]
leavesMatch LMatch GhcTc (Located (body GhcTc))
_ = String -> [(Located (body GhcTc), VarSet)]
forall a. String -> a
panic String
"leavesMatch"

-- Replace the leaf commands in a match

replaceLeavesMatch
        :: Type                                 -- new result type
        -> [Located (body' GhcTc)] -- replacement leaf expressions of that type
        -> LMatch GhcTc (Located (body GhcTc))  -- the matches of a case command
        -> ([Located (body' GhcTc)],            -- remaining leaf expressions
            LMatch GhcTc (Located (body' GhcTc))) -- updated match
replaceLeavesMatch :: Type
-> [Located (body' GhcTc)]
-> LMatch GhcTc (Located (body GhcTc))
-> ([Located (body' GhcTc)], LMatch GhcTc (Located (body' GhcTc)))
replaceLeavesMatch Type
_res_ty [Located (body' GhcTc)]
leaves
                        (LMatch GhcTc (Located (body GhcTc))
-> Located (SrcSpanLess (LMatch GhcTc (Located (body GhcTc))))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L SrcSpan
loc
                          match :: SrcSpanLess (LMatch GhcTc (Located (body GhcTc)))
match@(Match { m_grhss = GRHSs x grhss binds }))
  = let
        ([Located (body' GhcTc)]
leaves', [LGRHS GhcTc (Located (body' GhcTc))]
grhss') = ([Located (body' GhcTc)]
 -> LGRHS GhcTc (Located (body GhcTc))
 -> ([Located (body' GhcTc)], LGRHS GhcTc (Located (body' GhcTc))))
-> [Located (body' GhcTc)]
-> [LGRHS GhcTc (Located (body GhcTc))]
-> ([Located (body' GhcTc)], [LGRHS GhcTc (Located (body' GhcTc))])
forall (t :: * -> *) a b c.
Traversable t =>
(a -> b -> (a, c)) -> a -> t b -> (a, t c)
mapAccumL [Located (body' GhcTc)]
-> LGRHS GhcTc (Located (body GhcTc))
-> ([Located (body' GhcTc)], LGRHS GhcTc (Located (body' GhcTc)))
forall (body' :: * -> *) (body :: * -> *).
[Located (body' GhcTc)]
-> LGRHS GhcTc (Located (body GhcTc))
-> ([Located (body' GhcTc)], LGRHS GhcTc (Located (body' GhcTc)))
replaceLeavesGRHS [Located (body' GhcTc)]
leaves [LGRHS GhcTc (Located (body GhcTc))]
grhss
    in
    ([Located (body' GhcTc)]
leaves', SrcSpan
-> SrcSpanLess (LMatch GhcTc (Located (body' GhcTc)))
-> LMatch GhcTc (Located (body' GhcTc))
forall a. HasSrcSpan a => SrcSpan -> SrcSpanLess a -> a
cL SrcSpan
loc (SrcSpanLess (LMatch GhcTc (Located (body GhcTc)))
Match GhcTc (Located (body GhcTc))
match { m_ext :: XCMatch GhcTc (Located (body' GhcTc))
m_ext = XCMatch GhcTc (Located (body' GhcTc))
NoExtField
noExtField, m_grhss :: GRHSs GhcTc (Located (body' GhcTc))
m_grhss = XCGRHSs GhcTc (Located (body' GhcTc))
-> [LGRHS GhcTc (Located (body' GhcTc))]
-> LHsLocalBinds GhcTc
-> GRHSs GhcTc (Located (body' GhcTc))
forall p body.
XCGRHSs p body -> [LGRHS p body] -> LHsLocalBinds p -> GRHSs p body
GRHSs XCGRHSs GhcTc (Located (body' GhcTc))
XCGRHSs GhcTc (Located (body GhcTc))
x [LGRHS GhcTc (Located (body' GhcTc))]
grhss' LHsLocalBinds GhcTc
binds }))
replaceLeavesMatch Type
_ [Located (body' GhcTc)]
_ LMatch GhcTc (Located (body GhcTc))
_ = String
-> ([Located (body' GhcTc)], LMatch GhcTc (Located (body' GhcTc)))
forall a. String -> a
panic String
"replaceLeavesMatch"

replaceLeavesGRHS
        :: [Located (body' GhcTc)]  -- replacement leaf expressions of that type
        -> LGRHS GhcTc (Located (body GhcTc))     -- rhss of a case command
        -> ([Located (body' GhcTc)],              -- remaining leaf expressions
            LGRHS GhcTc (Located (body' GhcTc)))  -- updated GRHS
replaceLeavesGRHS :: [Located (body' GhcTc)]
-> LGRHS GhcTc (Located (body GhcTc))
-> ([Located (body' GhcTc)], LGRHS GhcTc (Located (body' GhcTc)))
replaceLeavesGRHS (Located (body' GhcTc)
leaf:[Located (body' GhcTc)]
leaves) (LGRHS GhcTc (Located (body GhcTc))
-> Located (SrcSpanLess (LGRHS GhcTc (Located (body GhcTc))))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L SrcSpan
loc (GRHS x stmts _))
  = ([Located (body' GhcTc)]
leaves, SrcSpan
-> SrcSpanLess (LGRHS GhcTc (Located (body' GhcTc)))
-> LGRHS GhcTc (Located (body' GhcTc))
forall a. HasSrcSpan a => SrcSpan -> SrcSpanLess a -> a
cL SrcSpan
loc (XCGRHS GhcTc (Located (body' GhcTc))
-> [LStmt GhcTc (LHsExpr GhcTc)]
-> Located (body' GhcTc)
-> GRHS GhcTc (Located (body' GhcTc))
forall p body.
XCGRHS p body -> [GuardLStmt p] -> body -> GRHS p body
GRHS XCGRHS GhcTc (Located (body' GhcTc))
XCGRHS GhcTc (Located (body GhcTc))
x [LStmt GhcTc (LHsExpr GhcTc)]
stmts Located (body' GhcTc)
leaf))
replaceLeavesGRHS [] LGRHS GhcTc (Located (body GhcTc))
_ = String
-> ([Located (body' GhcTc)], LGRHS GhcTc (Located (body' GhcTc)))
forall a. String -> a
panic String
"replaceLeavesGRHS []"
replaceLeavesGRHS [Located (body' GhcTc)]
_ LGRHS GhcTc (Located (body GhcTc))
_ = String
-> ([Located (body' GhcTc)], LGRHS GhcTc (Located (body' GhcTc)))
forall a. String -> a
panic String
"replaceLeavesGRHS"

-- Balanced fold of a non-empty list.

foldb :: (a -> a -> a) -> [a] -> a
foldb :: (a -> a -> a) -> [a] -> a
foldb a -> a -> a
_ [] = String -> a
forall a. HasCallStack => String -> a
error String
"foldb of empty list"
foldb a -> a -> a
_ [a
x] = a
x
foldb a -> a -> a
f [a]
xs = (a -> a -> a) -> [a] -> a
forall a. (a -> a -> a) -> [a] -> a
foldb a -> a -> a
f ([a] -> [a]
fold_pairs [a]
xs)
  where
    fold_pairs :: [a] -> [a]
fold_pairs [] = []
    fold_pairs [a
x] = [a
x]
    fold_pairs (a
x1:a
x2:[a]
xs) = a -> a -> a
f a
x1 a
x2a -> [a] -> [a]
forall a. a -> [a] -> [a]
:[a] -> [a]
fold_pairs [a]
xs

{-
Note [Dictionary binders in ConPatOut] See also same Note in GHC.Hs.Utils
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
The following functions to collect value variables from patterns are
copied from GHC.Hs.Utils, with one change: we also collect the dictionary
bindings (pat_binds) from ConPatOut.  We need them for cases like

h :: Arrow a => Int -> a (Int,Int) Int
h x = proc (y,z) -> case compare x y of
                GT -> returnA -< z+x

The type checker turns the case into

                case compare x y of
                  GT { p77 = plusInt } -> returnA -< p77 z x

Here p77 is a local binding for the (+) operation.

See comments in GHC.Hs.Utils for why the other version does not include
these bindings.
-}

collectPatBinders :: LPat GhcTc -> [Id]
collectPatBinders :: LPat GhcTc -> [Id]
collectPatBinders LPat GhcTc
pat = LPat GhcTc -> [Id] -> [Id]
collectl LPat GhcTc
pat []

collectPatsBinders :: [LPat GhcTc] -> [Id]
collectPatsBinders :: [LPat GhcTc] -> [Id]
collectPatsBinders [LPat GhcTc]
pats = (Located (Pat GhcTc) -> [Id] -> [Id])
-> [Id] -> [Located (Pat GhcTc)] -> [Id]
forall (t :: * -> *) a b.
Foldable t =>
(a -> b -> b) -> b -> t a -> b
foldr Located (Pat GhcTc) -> [Id] -> [Id]
LPat GhcTc -> [Id] -> [Id]
collectl [] [Located (Pat GhcTc)]
[LPat GhcTc]
pats

---------------------
collectl :: LPat GhcTc -> [Id] -> [Id]
-- See Note [Dictionary binders in ConPatOut]
collectl :: LPat GhcTc -> [Id] -> [Id]
collectl (LPat GhcTc -> Located (SrcSpanLess (Located (Pat GhcTc)))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L SrcSpan
_ SrcSpanLess (Located (Pat GhcTc))
pat) [Id]
bndrs
  = Pat GhcTc -> [Id]
go SrcSpanLess (Located (Pat GhcTc))
Pat GhcTc
pat
  where
    go :: Pat GhcTc -> [Id]
go (VarPat XVarPat GhcTc
_ (Located (IdP GhcTc) -> Located (SrcSpanLess (Located Id))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L SrcSpan
_ SrcSpanLess (Located Id)
var))   = SrcSpanLess (Located Id)
Id
var Id -> [Id] -> [Id]
forall a. a -> [a] -> [a]
: [Id]
bndrs
    go (WildPat XWildPat GhcTc
_)                = [Id]
bndrs
    go (LazyPat XLazyPat GhcTc
_ LPat GhcTc
pat)            = LPat GhcTc -> [Id] -> [Id]
collectl LPat GhcTc
pat [Id]
bndrs
    go (BangPat XBangPat GhcTc
_ LPat GhcTc
pat)            = LPat GhcTc -> [Id] -> [Id]
collectl LPat GhcTc
pat [Id]
bndrs
    go (AsPat XAsPat GhcTc
_ (Located (IdP GhcTc) -> Located (SrcSpanLess (Located Id))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L SrcSpan
_ SrcSpanLess (Located Id)
a) LPat GhcTc
pat)  = SrcSpanLess (Located Id)
Id
a Id -> [Id] -> [Id]
forall a. a -> [a] -> [a]
: LPat GhcTc -> [Id] -> [Id]
collectl LPat GhcTc
pat [Id]
bndrs
    go (ParPat XParPat GhcTc
_ LPat GhcTc
pat)             = LPat GhcTc -> [Id] -> [Id]
collectl LPat GhcTc
pat [Id]
bndrs

    go (ListPat XListPat GhcTc
_ [LPat GhcTc]
pats)           = (Located (Pat GhcTc) -> [Id] -> [Id])
-> [Id] -> [Located (Pat GhcTc)] -> [Id]
forall (t :: * -> *) a b.
Foldable t =>
(a -> b -> b) -> b -> t a -> b
foldr Located (Pat GhcTc) -> [Id] -> [Id]
LPat GhcTc -> [Id] -> [Id]
collectl [Id]
bndrs [Located (Pat GhcTc)]
[LPat GhcTc]
pats
    go (TuplePat XTuplePat GhcTc
_ [LPat GhcTc]
pats Boxity
_)        = (Located (Pat GhcTc) -> [Id] -> [Id])
-> [Id] -> [Located (Pat GhcTc)] -> [Id]
forall (t :: * -> *) a b.
Foldable t =>
(a -> b -> b) -> b -> t a -> b
foldr Located (Pat GhcTc) -> [Id] -> [Id]
LPat GhcTc -> [Id] -> [Id]
collectl [Id]
bndrs [Located (Pat GhcTc)]
[LPat GhcTc]
pats
    go (SumPat XSumPat GhcTc
_ LPat GhcTc
pat Int
_ Int
_)         = LPat GhcTc -> [Id] -> [Id]
collectl LPat GhcTc
pat [Id]
bndrs

    go (ConPatIn Located (IdP GhcTc)
_ HsConPatDetails GhcTc
ps)            = (Located (Pat GhcTc) -> [Id] -> [Id])
-> [Id] -> [Located (Pat GhcTc)] -> [Id]
forall (t :: * -> *) a b.
Foldable t =>
(a -> b -> b) -> b -> t a -> b
foldr Located (Pat GhcTc) -> [Id] -> [Id]
LPat GhcTc -> [Id] -> [Id]
collectl [Id]
bndrs (HsConPatDetails GhcTc -> [LPat GhcTc]
forall p. HsConPatDetails p -> [LPat p]
hsConPatArgs HsConPatDetails GhcTc
ps)
    go (ConPatOut {pat_args :: forall p. Pat p -> HsConPatDetails p
pat_args=HsConPatDetails GhcTc
ps, pat_binds :: forall p. Pat p -> TcEvBinds
pat_binds=TcEvBinds
ds}) =
                                    TcEvBinds -> [Id]
collectEvBinders TcEvBinds
ds
                                    [Id] -> [Id] -> [Id]
forall a. [a] -> [a] -> [a]
++ (Located (Pat GhcTc) -> [Id] -> [Id])
-> [Id] -> [Located (Pat GhcTc)] -> [Id]
forall (t :: * -> *) a b.
Foldable t =>
(a -> b -> b) -> b -> t a -> b
foldr Located (Pat GhcTc) -> [Id] -> [Id]
LPat GhcTc -> [Id] -> [Id]
collectl [Id]
bndrs (HsConPatDetails GhcTc -> [LPat GhcTc]
forall p. HsConPatDetails p -> [LPat p]
hsConPatArgs HsConPatDetails GhcTc
ps)
    go (LitPat XLitPat GhcTc
_ HsLit GhcTc
_)               = [Id]
bndrs
    go (NPat {})                  = [Id]
bndrs
    go (NPlusKPat XNPlusKPat GhcTc
_ (Located (IdP GhcTc) -> Located (SrcSpanLess (Located Id))
forall a. HasSrcSpan a => a -> Located (SrcSpanLess a)
dL->L SrcSpan
_ SrcSpanLess (Located Id)
n) Located (HsOverLit GhcTc)
_ HsOverLit GhcTc
_ SyntaxExpr GhcTc
_ SyntaxExpr GhcTc
_) = SrcSpanLess (Located Id)
Id
n Id -> [Id] -> [Id]
forall a. a -> [a] -> [a]
: [Id]
bndrs

    go (SigPat XSigPat GhcTc
_ LPat GhcTc
pat LHsSigWcType (NoGhcTc GhcTc)
_)           = LPat GhcTc -> [Id] -> [Id]
collectl LPat GhcTc
pat [Id]
bndrs
    go (CoPat XCoPat GhcTc
_ HsWrapper
_ Pat GhcTc
pat Type
_)          = LPat GhcTc -> [Id] -> [Id]
collectl (SrcSpanLess (Located (Pat GhcTc)) -> Located (Pat GhcTc)
forall a. HasSrcSpan a => SrcSpanLess a -> a
noLoc SrcSpanLess (Located (Pat GhcTc))
Pat GhcTc
pat) [Id]
bndrs
    go (ViewPat XViewPat GhcTc
_ LHsExpr GhcTc
_ LPat GhcTc
pat)          = LPat GhcTc -> [Id] -> [Id]
collectl LPat GhcTc
pat [Id]
bndrs
    go p :: Pat GhcTc
p@(SplicePat {})           = String -> SDoc -> [Id]
forall a. HasCallStack => String -> SDoc -> a
pprPanic String
"collectl/go" (Pat GhcTc -> SDoc
forall a. Outputable a => a -> SDoc
ppr Pat GhcTc
p)
    go p :: Pat GhcTc
p@(XPat {})                = String -> SDoc -> [Id]
forall a. HasCallStack => String -> SDoc -> a
pprPanic String
"collectl/go" (Pat GhcTc -> SDoc
forall a. Outputable a => a -> SDoc
ppr Pat GhcTc
p)

collectEvBinders :: TcEvBinds -> [Id]
collectEvBinders :: TcEvBinds -> [Id]
collectEvBinders (EvBinds Bag EvBind
bs)   = (EvBind -> [Id] -> [Id]) -> [Id] -> Bag EvBind -> [Id]
forall (t :: * -> *) a b.
Foldable t =>
(a -> b -> b) -> b -> t a -> b
foldr EvBind -> [Id] -> [Id]
add_ev_bndr [] Bag EvBind
bs
collectEvBinders (TcEvBinds {}) = String -> [Id]
forall a. String -> a
panic String
"ToDo: collectEvBinders"

add_ev_bndr :: EvBind -> [Id] -> [Id]
add_ev_bndr :: EvBind -> [Id] -> [Id]
add_ev_bndr (EvBind { eb_lhs :: EvBind -> Id
eb_lhs = Id
b }) [Id]
bs | Id -> Bool
isId Id
b    = Id
bId -> [Id] -> [Id]
forall a. a -> [a] -> [a]
:[Id]
bs
                                       | Bool
otherwise = [Id]
bs
  -- A worry: what about coercion variable binders??

collectLStmtsBinders :: [LStmt GhcTc body] -> [Id]
collectLStmtsBinders :: [LStmt GhcTc body] -> [Id]
collectLStmtsBinders = (LStmt GhcTc body -> [Id]) -> [LStmt GhcTc body] -> [Id]
forall (t :: * -> *) a b. Foldable t => (a -> [b]) -> t a -> [b]
concatMap LStmt GhcTc body -> [Id]
forall body. LStmt GhcTc body -> [Id]
collectLStmtBinders

collectLStmtBinders :: LStmt GhcTc body -> [Id]
collectLStmtBinders :: LStmt GhcTc body -> [Id]
collectLStmtBinders = Stmt GhcTc body -> [Id]
forall body. Stmt GhcTc body -> [Id]
collectStmtBinders (Stmt GhcTc body -> [Id])
-> (LStmt GhcTc body -> Stmt GhcTc body)
-> LStmt GhcTc body
-> [Id]
forall b c a. (b -> c) -> (a -> b) -> a -> c
. LStmt GhcTc body -> Stmt GhcTc body
forall a. HasSrcSpan a => a -> SrcSpanLess a
unLoc

collectStmtBinders :: Stmt GhcTc body -> [Id]
collectStmtBinders :: Stmt GhcTc body -> [Id]
collectStmtBinders (RecStmt { recS_later_ids :: forall idL idR body. StmtLR idL idR body -> [IdP idR]
recS_later_ids = [IdP GhcTc]
later_ids }) = [Id]
[IdP GhcTc]
later_ids
collectStmtBinders Stmt GhcTc body
stmt = Stmt GhcTc body -> [IdP GhcTc]
forall (idL :: Pass) (idR :: Pass) body.
StmtLR (GhcPass idL) (GhcPass idR) body -> [IdP (GhcPass idL)]
HsUtils.collectStmtBinders Stmt GhcTc body
stmt