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

    Utilities for desugaring

    This module exports some utility functions of no great interest.
    -}

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

    -- | Utility functions for constructing Core syntax, principally for desugaring
    module GHC.HsToCore.Utils (
            EquationInfo(..),
            firstPat, shiftEqns,

            MatchResult (..), CaseAlt(..),
            cantFailMatchResult, alwaysFailMatchResult,
            extractMatchResult, combineMatchResults,
            adjustMatchResultDs,
            shareFailureHandler,
            mkCoLetMatchResult, mkViewMatchResult, mkGuardedMatchResult,
            matchCanFail, mkEvalMatchResult,
            mkCoPrimCaseMatchResult, mkCoAlgCaseMatchResult, mkCoSynCaseMatchResult,
            wrapBind, wrapBinds,

            mkErrorAppDs, mkCoreAppDs, mkCoreAppsDs, mkCastDs,

            seqVar,

            -- LHs tuples
            mkLHsPatTup, mkVanillaTuplePat,
            mkBigLHsVarTupId, mkBigLHsTupId, mkBigLHsVarPatTupId, mkBigLHsPatTupId,

            mkSelectorBinds,

            selectSimpleMatchVarL, selectMatchVars, selectMatchVar,
            mkOptTickBox, mkBinaryTickBox, decideBangHood,
            isTrueLHsExpr
        ) where

    #include "HsVersions.h"

    import GHC.Prelude

    import {-# SOURCE #-} GHC.HsToCore.Match ( matchSimply )
    import {-# SOURCE #-} GHC.HsToCore.Expr  ( dsLExpr )

    import GHC.Hs
    import GHC.Tc.Utils.Zonk
    import GHC.Tc.Utils.TcType( tcSplitTyConApp )
    import GHC.Core
    import GHC.HsToCore.Monad

    import GHC.Core.Utils
    import GHC.Core.Make
    import GHC.Types.Id.Make
    import GHC.Types.Id
    import GHC.Types.Literal
    import GHC.Core.TyCon
    import GHC.Core.DataCon
    import GHC.Core.PatSyn
    import GHC.Core.Type
    import GHC.Core.Coercion
    import GHC.Builtin.Types.Prim
    import GHC.Builtin.Types
    import GHC.Types.Basic
    import GHC.Core.ConLike
    import GHC.Types.Unique.Set
    import GHC.Types.Unique.Supply
    import GHC.Unit.Module
    import GHC.Builtin.Names
    import GHC.Types.Name( isInternalName )
    import GHC.Utils.Outputable
    import GHC.Types.SrcLoc
    import GHC.Utils.Misc
    import GHC.Driver.Session
    import GHC.Data.FastString
    import qualified GHC.LanguageExtensions as LangExt

    import GHC.Tc.Types.Evidence

    import Control.Monad    ( zipWithM )
    import Data.List.NonEmpty (NonEmpty(..))
    import Data.Maybe (maybeToList)
    import qualified Data.List.NonEmpty as NEL

    {-
    ************************************************************************
    *                                                                      *
    \subsection{ Selecting match variables}
    *                                                                      *
    ************************************************************************

    We're about to match against some patterns.  We want to make some
    @Ids@ to use as match variables.  If a pattern has an @Id@ readily at
    hand, which should indeed be bound to the pattern as a whole, then use it;
    otherwise, make one up. The multiplicity argument is chosen as the multiplicity
    of the variable if it is made up.
    -}

    selectSimpleMatchVarL :: Mult -> LPat GhcTc -> DsM Id
    -- Postcondition: the returned Id has an Internal Name
    selectSimpleMatchVarL :: Mult -> XRec (GhcPass 'Typechecked) Pat -> DsM Id
    selectSimpleMatchVarL Mult
    w XRec (GhcPass 'Typechecked) Pat
    pat = Mult -> Pat (GhcPass 'Typechecked) -> DsM Id
    selectMatchVar Mult
    w (GenLocated SrcSpan (Pat (GhcPass 'Typechecked))
    -> Pat (GhcPass 'Typechecked)
    forall l e. GenLocated l e -> e
    unLoc GenLocated SrcSpan (Pat (GhcPass 'Typechecked))
    XRec (GhcPass 'Typechecked) Pat
    pat)

    -- (selectMatchVars ps tys) chooses variables of type tys
    -- to use for matching ps against.  If the pattern is a variable,
    -- we try to use that, to save inventing lots of fresh variables.
    --
    -- OLD, but interesting note:
    --    But even if it is a variable, its type might not match.  Consider
    --      data T a where
    --        T1 :: Int -> T Int
    --        T2 :: a   -> T a
    --
    --      f :: T a -> a -> Int
    --      f (T1 i) (x::Int) = x
    --      f (T2 i) (y::a)   = 0
    --    Then we must not choose (x::Int) as the matching variable!
    -- And nowadays we won't, because the (x::Int) will be wrapped in a CoPat

    selectMatchVars :: [(Mult, Pat GhcTc)] -> DsM [Id]
    -- Postcondition: the returned Ids have Internal Names
    selectMatchVars :: [(Mult, Pat (GhcPass 'Typechecked))] -> DsM [Id]
    selectMatchVars [(Mult, Pat (GhcPass 'Typechecked))]
    ps = ((Mult, Pat (GhcPass 'Typechecked)) -> DsM Id)
    -> [(Mult, Pat (GhcPass 'Typechecked))] -> DsM [Id]
    forall (t :: * -> *) (m :: * -> *) a b.
    (Traversable t, Monad m) =>
    (a -> m b) -> t a -> m (t b)
    mapM ((Mult -> Pat (GhcPass 'Typechecked) -> DsM Id)
    -> (Mult, Pat (GhcPass 'Typechecked)) -> DsM Id
    forall a b c. (a -> b -> c) -> (a, b) -> c
    uncurry Mult -> Pat (GhcPass 'Typechecked) -> DsM Id
    selectMatchVar) [(Mult, Pat (GhcPass 'Typechecked))]
    ps

    selectMatchVar :: Mult -> Pat GhcTc -> DsM Id
    -- Postcondition: the returned Id has an Internal Name
    selectMatchVar :: Mult -> Pat (GhcPass 'Typechecked) -> DsM Id
    selectMatchVar Mult
    w (BangPat XBangPat (GhcPass 'Typechecked)
    _ XRec (GhcPass 'Typechecked) Pat
    pat) = Mult -> Pat (GhcPass 'Typechecked) -> DsM Id
    selectMatchVar Mult
    w (GenLocated SrcSpan (Pat (GhcPass 'Typechecked))
    -> Pat (GhcPass 'Typechecked)
    forall l e. GenLocated l e -> e
    unLoc GenLocated SrcSpan (Pat (GhcPass 'Typechecked))
    XRec (GhcPass 'Typechecked) Pat
    pat)
    selectMatchVar Mult
    w (LazyPat XLazyPat (GhcPass 'Typechecked)
    _ XRec (GhcPass 'Typechecked) Pat
    pat) = Mult -> Pat (GhcPass 'Typechecked) -> DsM Id
    selectMatchVar Mult
    w (GenLocated SrcSpan (Pat (GhcPass 'Typechecked))
    -> Pat (GhcPass 'Typechecked)
    forall l e. GenLocated l e -> e
    unLoc GenLocated SrcSpan (Pat (GhcPass 'Typechecked))
    XRec (GhcPass 'Typechecked) Pat
    pat)
    selectMatchVar Mult
    w (ParPat XParPat (GhcPass 'Typechecked)
    _ XRec (GhcPass 'Typechecked) Pat
    pat)  = Mult -> Pat (GhcPass 'Typechecked) -> DsM Id
    selectMatchVar Mult
    w (GenLocated SrcSpan (Pat (GhcPass 'Typechecked))
    -> Pat (GhcPass 'Typechecked)
    forall l e. GenLocated l e -> e
    unLoc GenLocated SrcSpan (Pat (GhcPass 'Typechecked))
    XRec (GhcPass 'Typechecked) Pat
    pat)
    selectMatchVar Mult
    _w (VarPat XVarPat (GhcPass 'Typechecked)
    _ Located (IdP (GhcPass 'Typechecked))
    var)  = Id -> DsM Id
    forall (m :: * -> *) a. Monad m => a -> m a
    return (Id -> Id
    localiseId (GenLocated SrcSpan Id -> Id
    forall l e. GenLocated l e -> e
    unLoc GenLocated SrcSpan Id
    Located (IdP (GhcPass 'Typechecked))
    var))
                                      -- Note [Localise pattern binders]
                                      --
                                      -- Remark: when the pattern is a variable (or
                                      -- an @-pattern), then w is the same as the
                                      -- multiplicity stored within the variable
                                      -- itself. It's easier to pull it from the
                                      -- variable, so we ignore the multiplicity.
    selectMatchVar Mult
    _w (AsPat XAsPat (GhcPass 'Typechecked)
    _ Located (IdP (GhcPass 'Typechecked))
    var XRec (GhcPass 'Typechecked) Pat
    _) = ASSERT( isManyDataConTy _w ) (return (unLoc var))
    selectMatchVar Mult
    w Pat (GhcPass 'Typechecked)
    other_pat     = Mult -> Mult -> DsM Id
    newSysLocalDsNoLP Mult
    w (Pat (GhcPass 'Typechecked) -> Mult
    hsPatType Pat (GhcPass 'Typechecked)
    other_pat)

    {- Note [Localise pattern binders]
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    Consider     module M where
                   [Just a] = e
    After renaming it looks like
                 module M where
                   [Just M.a] = e

    We don't generalise, since it's a pattern binding, monomorphic, etc,
    so after desugaring we may get something like
                 M.a = case e of (v:_) ->
                       case v of Just M.a -> M.a
    Notice the "M.a" in the pattern; after all, it was in the original
    pattern.  However, after optimisation those pattern binders can become
    let-binders, and then end up floated to top level.  They have a
    different *unique* by then (the simplifier is good about maintaining
    proper scoping), but it's BAD to have two top-level bindings with the
    External Name M.a, because that turns into two linker symbols for M.a.
    It's quite rare for this to actually *happen* -- the only case I know
    of is tc003 compiled with the 'hpc' way -- but that only makes it
    all the more annoying.

    To avoid this, we craftily call 'localiseId' in the desugarer, which
    simply turns the External Name for the Id into an Internal one, but
    doesn't change the unique.  So the desugarer produces this:
                 M.a{r8} = case e of (v:_) ->
                           case v of Just a{r8} -> M.a{r8}
    The unique is still 'r8', but the binding site in the pattern
    is now an Internal Name.  Now the simplifier's usual mechanisms
    will propagate that Name to all the occurrence sites, as well as
    un-shadowing it, so we'll get
                 M.a{r8} = case e of (v:_) ->
                           case v of Just a{s77} -> a{s77}
    In fact, even GHC.Core.Subst.simplOptExpr will do this, and simpleOptExpr
    runs on the output of the desugarer, so all is well by the end of
    the desugaring pass.

    See also Note [MatchIds] in GHC.HsToCore.Match

    ************************************************************************
    *                                                                      *
    * type synonym EquationInfo and access functions for its pieces        *
    *                                                                      *
    ************************************************************************
    \subsection[EquationInfo-synonym]{@EquationInfo@: a useful synonym}

    The ``equation info'' used by @match@ is relatively complicated and
    worthy of a type synonym and a few handy functions.
    -}

    firstPat :: EquationInfo -> Pat GhcTc
    firstPat :: EquationInfo -> Pat (GhcPass 'Typechecked)
    firstPat EquationInfo
    eqn = ASSERT( notNull (eqn_pats eqn) ) head (eqn_pats eqn)

    shiftEqns :: Functor f => f EquationInfo -> f EquationInfo
    -- Drop the first pattern in each equation
    shiftEqns :: forall (f :: * -> *). Functor f => f EquationInfo -> f EquationInfo
    shiftEqns = (EquationInfo -> EquationInfo) -> f EquationInfo -> f EquationInfo
    forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
    fmap ((EquationInfo -> EquationInfo)
     -> f EquationInfo -> f EquationInfo)
    -> (EquationInfo -> EquationInfo)
    -> f EquationInfo
    -> f EquationInfo
    forall a b. (a -> b) -> a -> b
    $ \EquationInfo
    eqn -> EquationInfo
    eqn { eqn_pats :: [Pat (GhcPass 'Typechecked)]
    eqn_pats = [Pat (GhcPass 'Typechecked)] -> [Pat (GhcPass 'Typechecked)]
    forall a. [a] -> [a]
    tail (EquationInfo -> [Pat (GhcPass 'Typechecked)]
    eqn_pats EquationInfo
    eqn) }

    -- Functions on MatchResult CoreExprs

    matchCanFail :: MatchResult a -> Bool
    matchCanFail :: forall a. MatchResult a -> Bool
    matchCanFail (MR_Fallible {})  = Bool
    True
    matchCanFail (MR_Infallible {}) = Bool
    False

    alwaysFailMatchResult :: MatchResult CoreExpr
    alwaysFailMatchResult :: MatchResult CoreExpr
    alwaysFailMatchResult = (CoreExpr -> DsM CoreExpr) -> MatchResult CoreExpr
    forall a. (CoreExpr -> DsM a) -> MatchResult a
    MR_Fallible ((CoreExpr -> DsM CoreExpr) -> MatchResult CoreExpr)
    -> (CoreExpr -> DsM CoreExpr) -> MatchResult CoreExpr
    forall a b. (a -> b) -> a -> b
    $ \CoreExpr
    fail -> CoreExpr -> DsM CoreExpr
    forall (m :: * -> *) a. Monad m => a -> m a
    return CoreExpr
    fail

    cantFailMatchResult :: CoreExpr -> MatchResult CoreExpr
    cantFailMatchResult :: CoreExpr -> MatchResult CoreExpr
    cantFailMatchResult CoreExpr
    expr = DsM CoreExpr -> MatchResult CoreExpr
    forall a. DsM a -> MatchResult a
    MR_Infallible (DsM CoreExpr -> MatchResult CoreExpr)
    -> DsM CoreExpr -> MatchResult CoreExpr
    forall a b. (a -> b) -> a -> b
    $ CoreExpr -> DsM CoreExpr
    forall (m :: * -> *) a. Monad m => a -> m a
    return CoreExpr
    expr

    extractMatchResult :: MatchResult CoreExpr -> CoreExpr -> DsM CoreExpr
    extractMatchResult :: MatchResult CoreExpr -> CoreExpr -> DsM CoreExpr
    extractMatchResult MatchResult CoreExpr
    match_result CoreExpr
    failure_expr =
      CoreExpr -> MatchResult CoreExpr -> DsM CoreExpr
    forall a. CoreExpr -> MatchResult a -> DsM a
    runMatchResult
        CoreExpr
    failure_expr
        (MatchResult CoreExpr -> MatchResult CoreExpr
    shareFailureHandler MatchResult CoreExpr
    match_result)

    combineMatchResults :: MatchResult CoreExpr -> MatchResult CoreExpr -> MatchResult CoreExpr
    combineMatchResults :: MatchResult CoreExpr
    -> MatchResult CoreExpr -> MatchResult CoreExpr
    combineMatchResults match_result1 :: MatchResult CoreExpr
    match_result1@(MR_Infallible DsM CoreExpr
    _) MatchResult CoreExpr
    _
      = MatchResult CoreExpr
    match_result1
    combineMatchResults MatchResult CoreExpr
    match_result1 MatchResult CoreExpr
    match_result2 =
      -- if the first pattern needs a failure handler (i.e. if it is fallible),
      -- make it let-bind it bind it with `shareFailureHandler`.
      case MatchResult CoreExpr -> MatchResult CoreExpr
    shareFailureHandler MatchResult CoreExpr
    match_result1 of
        MR_Infallible DsM CoreExpr
    _ -> MatchResult CoreExpr
    match_result1
        MR_Fallible CoreExpr -> DsM CoreExpr
    body_fn1 -> (CoreExpr -> DsM CoreExpr) -> MatchResult CoreExpr
    forall a. (CoreExpr -> DsM a) -> MatchResult a
    MR_Fallible ((CoreExpr -> DsM CoreExpr) -> MatchResult CoreExpr)
    -> (CoreExpr -> DsM CoreExpr) -> MatchResult CoreExpr
    forall a b. (a -> b) -> a -> b
    $ \CoreExpr
    fail_expr ->
          -- Before actually failing, try the next match arm.
          CoreExpr -> DsM CoreExpr
    body_fn1 (CoreExpr -> DsM CoreExpr) -> DsM CoreExpr -> DsM CoreExpr
    forall (m :: * -> *) a b. Monad m => (a -> m b) -> m a -> m b
    =<< CoreExpr -> MatchResult CoreExpr -> DsM CoreExpr
    forall a. CoreExpr -> MatchResult a -> DsM a
    runMatchResult CoreExpr
    fail_expr MatchResult CoreExpr
    match_result2

    adjustMatchResultDs :: (a -> DsM b) -> MatchResult a -> MatchResult b
    adjustMatchResultDs :: forall a b. (a -> DsM b) -> MatchResult a -> MatchResult b
    adjustMatchResultDs a -> DsM b
    encl_fn = \case
      MR_Infallible DsM a
    body_fn -> DsM b -> MatchResult b
    forall a. DsM a -> MatchResult a
    MR_Infallible (DsM b -> MatchResult b) -> DsM b -> MatchResult b
    forall a b. (a -> b) -> a -> b
    $
        a -> DsM b
    encl_fn (a -> DsM b) -> DsM a -> DsM b
    forall (m :: * -> *) a b. Monad m => (a -> m b) -> m a -> m b
    =<< DsM a
    body_fn
      MR_Fallible CoreExpr -> DsM a
    body_fn -> (CoreExpr -> DsM b) -> MatchResult b
    forall a. (CoreExpr -> DsM a) -> MatchResult a
    MR_Fallible ((CoreExpr -> DsM b) -> MatchResult b)
    -> (CoreExpr -> DsM b) -> MatchResult b
    forall a b. (a -> b) -> a -> b
    $ \CoreExpr
    fail ->
        a -> DsM b
    encl_fn (a -> DsM b) -> DsM a -> DsM b
    forall (m :: * -> *) a b. Monad m => (a -> m b) -> m a -> m b
    =<< CoreExpr -> DsM a
    body_fn CoreExpr
    fail

    wrapBinds :: [(Var,Var)] -> CoreExpr -> CoreExpr
    wrapBinds :: [(Id, Id)] -> CoreExpr -> CoreExpr
    wrapBinds [] CoreExpr
    e = CoreExpr
    e
    wrapBinds ((Id
    new,Id
    old):[(Id, Id)]
    prs) CoreExpr
    e = Id -> Id -> CoreExpr -> CoreExpr
    wrapBind Id
    new Id
    old ([(Id, Id)] -> CoreExpr -> CoreExpr
    wrapBinds [(Id, Id)]
    prs CoreExpr
    e)

    wrapBind :: Var -> Var -> CoreExpr -> CoreExpr
    wrapBind :: Id -> Id -> CoreExpr -> CoreExpr
    wrapBind Id
    new Id
    old CoreExpr
    body   -- NB: this function must deal with term
      | Id
    newId -> Id -> Bool
    forall a. Eq a => a -> a -> Bool
    ==Id
    old    = CoreExpr
    body  -- variables, type variables or coercion variables
      | Bool
    otherwise   = Bind Id -> CoreExpr -> CoreExpr
    forall b. Bind b -> Expr b -> Expr b
    Let (Id -> CoreExpr -> Bind Id
    forall b. b -> Expr b -> Bind b
    NonRec Id
    new (Id -> CoreExpr
    forall b. Id -> Expr b
    varToCoreExpr Id
    old)) CoreExpr
    body

    seqVar :: Var -> CoreExpr -> CoreExpr
    seqVar :: Id -> CoreExpr -> CoreExpr
    seqVar Id
    var CoreExpr
    body = CoreExpr -> Id -> CoreExpr -> CoreExpr
    mkDefaultCase (Id -> CoreExpr
    forall b. Id -> Expr b
    Var Id
    var) Id
    var CoreExpr
    body

    mkCoLetMatchResult :: CoreBind -> MatchResult CoreExpr -> MatchResult CoreExpr
    mkCoLetMatchResult :: Bind Id -> MatchResult CoreExpr -> MatchResult CoreExpr
    mkCoLetMatchResult Bind Id
    bind = (CoreExpr -> CoreExpr)
    -> MatchResult CoreExpr -> MatchResult CoreExpr
    forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
    fmap (Bind Id -> CoreExpr -> CoreExpr
    mkCoreLet Bind Id
    bind)

    -- (mkViewMatchResult var' viewExpr mr) makes the expression
    -- let var' = viewExpr in mr
    mkViewMatchResult :: Id -> CoreExpr -> MatchResult CoreExpr -> MatchResult CoreExpr
    mkViewMatchResult :: Id -> CoreExpr -> MatchResult CoreExpr -> MatchResult CoreExpr
    mkViewMatchResult Id
    var' CoreExpr
    viewExpr = (CoreExpr -> CoreExpr)
    -> MatchResult CoreExpr -> MatchResult CoreExpr
    forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
    fmap ((CoreExpr -> CoreExpr)
     -> MatchResult CoreExpr -> MatchResult CoreExpr)
    -> (CoreExpr -> CoreExpr)
    -> MatchResult CoreExpr
    -> MatchResult CoreExpr
    forall a b. (a -> b) -> a -> b
    $ Bind Id -> CoreExpr -> CoreExpr
    mkCoreLet (Bind Id -> CoreExpr -> CoreExpr)
    -> Bind Id -> CoreExpr -> CoreExpr
    forall a b. (a -> b) -> a -> b
    $ Id -> CoreExpr -> Bind Id
    forall b. b -> Expr b -> Bind b
    NonRec Id
    var' CoreExpr
    viewExpr

    mkEvalMatchResult :: Id -> Type -> MatchResult CoreExpr -> MatchResult CoreExpr
    mkEvalMatchResult :: Id -> Mult -> MatchResult CoreExpr -> MatchResult CoreExpr
    mkEvalMatchResult Id
    var Mult
    ty = (CoreExpr -> CoreExpr)
    -> MatchResult CoreExpr -> MatchResult CoreExpr
    forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
    fmap ((CoreExpr -> CoreExpr)
     -> MatchResult CoreExpr -> MatchResult CoreExpr)
    -> (CoreExpr -> CoreExpr)
    -> MatchResult CoreExpr
    -> MatchResult CoreExpr
    forall a b. (a -> b) -> a -> b
    $ \CoreExpr
    e ->
      CoreExpr -> Id -> Mult -> [Alt Id] -> CoreExpr
    forall b. Expr b -> b -> Mult -> [Alt b] -> Expr b
    Case (Id -> CoreExpr
    forall b. Id -> Expr b
    Var Id
    var) Id
    var Mult
    ty [(AltCon
    DEFAULT, [], CoreExpr
    e)]

    mkGuardedMatchResult :: CoreExpr -> MatchResult CoreExpr -> MatchResult CoreExpr
    mkGuardedMatchResult :: CoreExpr -> MatchResult CoreExpr -> MatchResult CoreExpr
    mkGuardedMatchResult CoreExpr
    pred_expr MatchResult CoreExpr
    mr = (CoreExpr -> DsM CoreExpr) -> MatchResult CoreExpr
    forall a. (CoreExpr -> DsM a) -> MatchResult a
    MR_Fallible ((CoreExpr -> DsM CoreExpr) -> MatchResult CoreExpr)
    -> (CoreExpr -> DsM CoreExpr) -> MatchResult CoreExpr
    forall a b. (a -> b) -> a -> b
    $ \CoreExpr
    fail -> do
      CoreExpr
    body <- CoreExpr -> MatchResult CoreExpr -> DsM CoreExpr
    forall a. CoreExpr -> MatchResult a -> DsM a
    runMatchResult CoreExpr
    fail MatchResult CoreExpr
    mr
      CoreExpr -> DsM CoreExpr
    forall (m :: * -> *) a. Monad m => a -> m a
    return (CoreExpr -> CoreExpr -> CoreExpr -> CoreExpr
    mkIfThenElse CoreExpr
    pred_expr CoreExpr
    body CoreExpr
    fail)

    mkCoPrimCaseMatchResult :: Id                  -- Scrutinee
                            -> Type                      -- Type of the case
                            -> [(Literal, MatchResult CoreExpr)]  -- Alternatives
                            -> MatchResult CoreExpr               -- Literals are all unlifted
    mkCoPrimCaseMatchResult :: Id
    -> Mult
    -> [(Literal, MatchResult CoreExpr)]
    -> MatchResult CoreExpr
    mkCoPrimCaseMatchResult Id
    var Mult
    ty [(Literal, MatchResult CoreExpr)]
    match_alts
      = (CoreExpr -> DsM CoreExpr) -> MatchResult CoreExpr
    forall a. (CoreExpr -> DsM a) -> MatchResult a
    MR_Fallible CoreExpr -> DsM CoreExpr
    mk_case
      where
        mk_case :: CoreExpr -> DsM CoreExpr
    mk_case CoreExpr
    fail = do
            [Alt Id]
    alts <- ((Literal, MatchResult CoreExpr)
     -> IOEnv (Env DsGblEnv DsLclEnv) (Alt Id))
    -> [(Literal, MatchResult CoreExpr)]
    -> IOEnv (Env DsGblEnv DsLclEnv) [Alt Id]
    forall (t :: * -> *) (m :: * -> *) a b.
    (Traversable t, Monad m) =>
    (a -> m b) -> t a -> m (t b)
    mapM (CoreExpr
    -> (Literal, MatchResult CoreExpr)
    -> IOEnv (Env DsGblEnv DsLclEnv) (Alt Id)
    forall {c} {a}.
    CoreExpr
    -> (Literal, MatchResult c)
    -> IOEnv (Env DsGblEnv DsLclEnv) (AltCon, [a], c)
    mk_alt CoreExpr
    fail) [(Literal, MatchResult CoreExpr)]
    sorted_alts
            CoreExpr -> DsM CoreExpr
    forall (m :: * -> *) a. Monad m => a -> m a
    return (CoreExpr -> Id -> Mult -> [Alt Id] -> CoreExpr
    forall b. Expr b -> b -> Mult -> [Alt b] -> Expr b
    Case (Id -> CoreExpr
    forall b. Id -> Expr b
    Var Id
    var) Id
    var Mult
    ty ((AltCon
    DEFAULT, [], CoreExpr
    fail) Alt Id -> [Alt Id] -> [Alt Id]
    forall a. a -> [a] -> [a]
    : [Alt Id]
    alts))

        sorted_alts :: [(Literal, MatchResult CoreExpr)]
    sorted_alts = ((Literal, MatchResult CoreExpr) -> Literal)
    -> [(Literal, MatchResult CoreExpr)]
    -> [(Literal, MatchResult CoreExpr)]
    forall b a. Ord b => (a -> b) -> [a] -> [a]
    sortWith (Literal, MatchResult CoreExpr) -> Literal
    forall a b. (a, b) -> a
    fst [(Literal, MatchResult CoreExpr)]
    match_alts       -- Right order for a Case
        mk_alt :: CoreExpr
    -> (Literal, MatchResult c)
    -> IOEnv (Env DsGblEnv DsLclEnv) (AltCon, [a], c)
    mk_alt CoreExpr
    fail (Literal
    lit, MatchResult c
    mr)
           = ASSERT( not (litIsLifted lit) )
             do c
    body <- CoreExpr -> MatchResult c -> DsM c
    forall a. CoreExpr -> MatchResult a -> DsM a
    runMatchResult CoreExpr
    fail MatchResult c
    mr
                (AltCon, [a], c) -> IOEnv (Env DsGblEnv DsLclEnv) (AltCon, [a], c)
    forall (m :: * -> *) a. Monad m => a -> m a
    return (Literal -> AltCon
    LitAlt Literal
    lit, [], c
    body)

    data CaseAlt a = MkCaseAlt{ forall a. CaseAlt a -> a
    alt_pat :: a,
                                forall a. CaseAlt a -> [Id]
    alt_bndrs :: [Var],
                                forall a. CaseAlt a -> HsWrapper
    alt_wrapper :: HsWrapper,
                                forall a. CaseAlt a -> MatchResult CoreExpr
    alt_result :: MatchResult CoreExpr }

    mkCoAlgCaseMatchResult
      :: Id -- ^ Scrutinee
      -> Type -- ^ Type of exp
      -> NonEmpty (CaseAlt DataCon) -- ^ Alternatives (bndrs *include* tyvars, dicts)
      -> MatchResult CoreExpr
    mkCoAlgCaseMatchResult :: Id -> Mult -> NonEmpty (CaseAlt DataCon) -> MatchResult CoreExpr
    mkCoAlgCaseMatchResult Id
    var Mult
    ty NonEmpty (CaseAlt DataCon)
    match_alts
      | Bool
    isNewtype  -- Newtype case; use a let
      = ASSERT( null match_alts_tail && null (tail arg_ids1) )
        Bind Id -> MatchResult CoreExpr -> MatchResult CoreExpr
    mkCoLetMatchResult (Id -> CoreExpr -> Bind Id
    forall b. b -> Expr b -> Bind b
    NonRec Id
    arg_id1 CoreExpr
    newtype_rhs) MatchResult CoreExpr
    match_result1

      | Bool
    otherwise
      = Id -> Mult -> NonEmpty (CaseAlt DataCon) -> MatchResult CoreExpr
    mkDataConCase Id
    var Mult
    ty NonEmpty (CaseAlt DataCon)
    match_alts
      where
        isNewtype :: Bool
    isNewtype = TyCon -> Bool
    isNewTyCon (DataCon -> TyCon
    dataConTyCon (CaseAlt DataCon -> DataCon
    forall a. CaseAlt a -> a
    alt_pat CaseAlt DataCon
    alt1))

            -- [Interesting: because of GADTs, we can't rely on the type of
            --  the scrutinised Id to be sufficiently refined to have a TyCon in it]

        alt1 :: CaseAlt DataCon
    alt1@MkCaseAlt{ alt_bndrs :: forall a. CaseAlt a -> [Id]
    alt_bndrs = [Id]
    arg_ids1, alt_result :: forall a. CaseAlt a -> MatchResult CoreExpr
    alt_result = MatchResult CoreExpr
    match_result1 } :| [CaseAlt DataCon]
    match_alts_tail
          = NonEmpty (CaseAlt DataCon)
    match_alts
        -- Stuff for newtype
        arg_id1 :: Id
    arg_id1       = ASSERT( notNull arg_ids1 ) head arg_ids1
        var_ty :: Mult
    var_ty        = Id -> Mult
    idType Id
    var
        (TyCon
    tc, [Mult]
    ty_args) = Mult -> (TyCon, [Mult])
    tcSplitTyConApp Mult
    var_ty      -- Don't look through newtypes
                                                    -- (not that splitTyConApp does, these days)
        newtype_rhs :: CoreExpr
    newtype_rhs = TyCon -> [Mult] -> CoreExpr -> CoreExpr
    unwrapNewTypeBody TyCon
    tc [Mult]
    ty_args (Id -> CoreExpr
    forall b. Id -> Expr b
    Var Id
    var)

    mkCoSynCaseMatchResult :: Id -> Type -> CaseAlt PatSyn -> MatchResult CoreExpr
    mkCoSynCaseMatchResult :: Id -> Mult -> CaseAlt PatSyn -> MatchResult CoreExpr
    mkCoSynCaseMatchResult Id
    var Mult
    ty CaseAlt PatSyn
    alt = (CoreExpr -> DsM CoreExpr) -> MatchResult CoreExpr
    forall a. (CoreExpr -> DsM a) -> MatchResult a
    MR_Fallible ((CoreExpr -> DsM CoreExpr) -> MatchResult CoreExpr)
    -> (CoreExpr -> DsM CoreExpr) -> MatchResult CoreExpr
    forall a b. (a -> b) -> a -> b
    $ Id -> Mult -> CaseAlt PatSyn -> CoreExpr -> DsM CoreExpr
    mkPatSynCase Id
    var Mult
    ty CaseAlt PatSyn
    alt

    mkPatSynCase :: Id -> Type -> CaseAlt PatSyn -> CoreExpr -> DsM CoreExpr
    mkPatSynCase :: Id -> Mult -> CaseAlt PatSyn -> CoreExpr -> DsM CoreExpr
    mkPatSynCase Id
    var Mult
    ty CaseAlt PatSyn
    alt CoreExpr
    fail = do
        CoreExpr
    matcher <- LHsExpr (GhcPass 'Typechecked) -> DsM CoreExpr
    dsLExpr (LHsExpr (GhcPass 'Typechecked) -> DsM CoreExpr)
    -> LHsExpr (GhcPass 'Typechecked) -> DsM CoreExpr
    forall a b. (a -> b) -> a -> b
    $ HsWrapper
    -> LHsExpr (GhcPass 'Typechecked) -> LHsExpr (GhcPass 'Typechecked)
    mkLHsWrap HsWrapper
    wrapper (LHsExpr (GhcPass 'Typechecked) -> LHsExpr (GhcPass 'Typechecked))
    -> LHsExpr (GhcPass 'Typechecked) -> LHsExpr (GhcPass 'Typechecked)
    forall a b. (a -> b) -> a -> b
    $
                             Id -> [Mult] -> LHsExpr (GhcPass 'Typechecked)
    nlHsTyApp Id
    matcher [HasDebugCallStack => Mult -> Mult
    Mult -> Mult
    getRuntimeRep Mult
    ty, Mult
    ty]
        CoreExpr
    cont <- [Id] -> CoreExpr -> CoreExpr
    mkCoreLams [Id]
    bndrs (CoreExpr -> CoreExpr) -> DsM CoreExpr -> DsM CoreExpr
    forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
    <$> CoreExpr -> MatchResult CoreExpr -> DsM CoreExpr
    forall a. CoreExpr -> MatchResult a -> DsM a
    runMatchResult CoreExpr
    fail MatchResult CoreExpr
    match_result
        CoreExpr -> DsM CoreExpr
    forall (m :: * -> *) a. Monad m => a -> m a
    return (CoreExpr -> DsM CoreExpr) -> CoreExpr -> DsM CoreExpr
    forall a b. (a -> b) -> a -> b
    $ SDoc -> CoreExpr -> [CoreExpr] -> CoreExpr
    mkCoreAppsDs (String -> SDoc
    text String
    "patsyn" SDoc -> SDoc -> SDoc
    <+> Id -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr Id
    var) CoreExpr
    matcher [Id -> CoreExpr
    forall b. Id -> Expr b
    Var Id
    var, CoreExpr -> CoreExpr
    ensure_unstrict CoreExpr
    cont, Id -> CoreExpr -> CoreExpr
    forall b. b -> Expr b -> Expr b
    Lam Id
    voidArgId CoreExpr
    fail]
      where
        MkCaseAlt{ alt_pat :: forall a. CaseAlt a -> a
    alt_pat = PatSyn
    psyn,
                   alt_bndrs :: forall a. CaseAlt a -> [Id]
    alt_bndrs = [Id]
    bndrs,
                   alt_wrapper :: forall a. CaseAlt a -> HsWrapper
    alt_wrapper = HsWrapper
    wrapper,
                   alt_result :: forall a. CaseAlt a -> MatchResult CoreExpr
    alt_result = MatchResult CoreExpr
    match_result} = CaseAlt PatSyn
    alt
        (Id
    matcher, Bool
    needs_void_lam) = PatSyn -> (Id, Bool)
    patSynMatcher PatSyn
    psyn

        -- See Note [Matchers and builders for pattern synonyms] in GHC.Core.PatSyn
        -- on these extra Void# arguments
        ensure_unstrict :: CoreExpr -> CoreExpr
    ensure_unstrict CoreExpr
    cont | Bool
    needs_void_lam = Id -> CoreExpr -> CoreExpr
    forall b. b -> Expr b -> Expr b
    Lam Id
    voidArgId CoreExpr
    cont
                             | Bool
    otherwise      = CoreExpr
    cont

    mkDataConCase :: Id -> Type -> NonEmpty (CaseAlt DataCon) -> MatchResult CoreExpr
    mkDataConCase :: Id -> Mult -> NonEmpty (CaseAlt DataCon) -> MatchResult CoreExpr
    mkDataConCase Id
    var Mult
    ty alts :: NonEmpty (CaseAlt DataCon)
    alts@(CaseAlt DataCon
    alt1 :| [CaseAlt DataCon]
    _)
        = (Maybe (Alt Id) -> [Alt Id] -> CoreExpr)
    -> MatchResult (Maybe (Alt Id))
    -> MatchResult [Alt Id]
    -> MatchResult CoreExpr
    forall (f :: * -> *) a b c.
    Applicative f =>
    (a -> b -> c) -> f a -> f b -> f c
    liftA2 Maybe (Alt Id) -> [Alt Id] -> CoreExpr
    mk_case MatchResult (Maybe (Alt Id))
    mk_default MatchResult [Alt Id]
    mk_alts
        -- The liftA2 combines the failability of all the alternatives and the default
      where
        con1 :: DataCon
    con1          = CaseAlt DataCon -> DataCon
    forall a. CaseAlt a -> a
    alt_pat CaseAlt DataCon
    alt1
        tycon :: TyCon
    tycon         = DataCon -> TyCon
    dataConTyCon DataCon
    con1
        data_cons :: [DataCon]
    data_cons     = TyCon -> [DataCon]
    tyConDataCons TyCon
    tycon

        sorted_alts :: [ CaseAlt DataCon ]
        sorted_alts :: [CaseAlt DataCon]
    sorted_alts  = (CaseAlt DataCon -> ConTag)
    -> [CaseAlt DataCon] -> [CaseAlt DataCon]
    forall b a. Ord b => (a -> b) -> [a] -> [a]
    sortWith (DataCon -> ConTag
    dataConTag (DataCon -> ConTag)
    -> (CaseAlt DataCon -> DataCon) -> CaseAlt DataCon -> ConTag
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . CaseAlt DataCon -> DataCon
    forall a. CaseAlt a -> a
    alt_pat) ([CaseAlt DataCon] -> [CaseAlt DataCon])
    -> [CaseAlt DataCon] -> [CaseAlt DataCon]
    forall a b. (a -> b) -> a -> b
    $ NonEmpty (CaseAlt DataCon) -> [CaseAlt DataCon]
    forall a. NonEmpty a -> [a]
    NEL.toList NonEmpty (CaseAlt DataCon)
    alts

        var_ty :: Mult
    var_ty       = Id -> Mult
    idType Id
    var
        (TyCon
    _, [Mult]
    ty_args) = Mult -> (TyCon, [Mult])
    tcSplitTyConApp Mult
    var_ty -- Don't look through newtypes
                                              -- (not that splitTyConApp does, these days)

        mk_case :: Maybe CoreAlt -> [CoreAlt] -> CoreExpr
        mk_case :: Maybe (Alt Id) -> [Alt Id] -> CoreExpr
    mk_case Maybe (Alt Id)
    def [Alt Id]
    alts = CoreExpr -> Scaled Mult -> Mult -> [Alt Id] -> CoreExpr
    mkWildCase (Id -> CoreExpr
    forall b. Id -> Expr b
    Var Id
    var) (Id -> Scaled Mult
    idScaledType Id
    var) Mult
    ty ([Alt Id] -> CoreExpr) -> [Alt Id] -> CoreExpr
    forall a b. (a -> b) -> a -> b
    $
          Maybe (Alt Id) -> [Alt Id]
    forall a. Maybe a -> [a]
    maybeToList Maybe (Alt Id)
    def [Alt Id] -> [Alt Id] -> [Alt Id]
    forall a. [a] -> [a] -> [a]
    ++ [Alt Id]
    alts

        mk_alts :: MatchResult [CoreAlt]
        mk_alts :: MatchResult [Alt Id]
    mk_alts = (CaseAlt DataCon -> MatchResult (Alt Id))
    -> [CaseAlt DataCon] -> MatchResult [Alt Id]
    forall (t :: * -> *) (f :: * -> *) a b.
    (Traversable t, Applicative f) =>
    (a -> f b) -> t a -> f (t b)
    traverse CaseAlt DataCon -> MatchResult (Alt Id)
    mk_alt [CaseAlt DataCon]
    sorted_alts

        mk_alt :: CaseAlt DataCon -> MatchResult CoreAlt
        mk_alt :: CaseAlt DataCon -> MatchResult (Alt Id)
    mk_alt MkCaseAlt { alt_pat :: forall a. CaseAlt a -> a
    alt_pat = DataCon
    con
                         , alt_bndrs :: forall a. CaseAlt a -> [Id]
    alt_bndrs = [Id]
    args
                         , alt_result :: forall a. CaseAlt a -> MatchResult CoreExpr
    alt_result = MatchResult CoreExpr
    match_result } =
          ((CoreExpr -> IOEnv (Env DsGblEnv DsLclEnv) (Alt Id))
     -> MatchResult CoreExpr -> MatchResult (Alt Id))
    -> MatchResult CoreExpr
    -> (CoreExpr -> IOEnv (Env DsGblEnv DsLclEnv) (Alt Id))
    -> MatchResult (Alt Id)
    forall a b c. (a -> b -> c) -> b -> a -> c
    flip (CoreExpr -> IOEnv (Env DsGblEnv DsLclEnv) (Alt Id))
    -> MatchResult CoreExpr -> MatchResult (Alt Id)
    forall a b. (a -> DsM b) -> MatchResult a -> MatchResult b
    adjustMatchResultDs MatchResult CoreExpr
    match_result ((CoreExpr -> IOEnv (Env DsGblEnv DsLclEnv) (Alt Id))
     -> MatchResult (Alt Id))
    -> (CoreExpr -> IOEnv (Env DsGblEnv DsLclEnv) (Alt Id))
    -> MatchResult (Alt Id)
    forall a b. (a -> b) -> a -> b
    $ \CoreExpr
    body -> do
            case DataCon -> Maybe DataConBoxer
    dataConBoxer DataCon
    con of
              Maybe DataConBoxer
    Nothing -> Alt Id -> IOEnv (Env DsGblEnv DsLclEnv) (Alt Id)
    forall (m :: * -> *) a. Monad m => a -> m a
    return (DataCon -> AltCon
    DataAlt DataCon
    con, [Id]
    args, CoreExpr
    body)
              Just (DCB [Mult] -> [Id] -> UniqSM ([Id], [Bind Id])
    boxer) -> do
                UniqSupply
    us <- TcRnIf DsGblEnv DsLclEnv UniqSupply
    forall gbl lcl. TcRnIf gbl lcl UniqSupply
    newUniqueSupply
                let ([Id]
    rep_ids, [Bind Id]
    binds) = UniqSupply -> UniqSM ([Id], [Bind Id]) -> ([Id], [Bind Id])
    forall a. UniqSupply -> UniqSM a -> a
    initUs_ UniqSupply
    us ([Mult] -> [Id] -> UniqSM ([Id], [Bind Id])
    boxer [Mult]
    ty_args [Id]
    args)
                let rep_ids' :: [Id]
    rep_ids' = (Id -> Id) -> [Id] -> [Id]
    forall a b. (a -> b) -> [a] -> [b]
    map (Mult -> Id -> Id
    scaleVarBy (Id -> Mult
    idMult Id
    var)) [Id]
    rep_ids
                  -- Upholds the invariant that the binders of a case expression
                  -- must be scaled by the case multiplicity. See Note [Case
                  -- expression invariants] in CoreSyn.
                Alt Id -> IOEnv (Env DsGblEnv DsLclEnv) (Alt Id)
    forall (m :: * -> *) a. Monad m => a -> m a
    return (DataCon -> AltCon
    DataAlt DataCon
    con, [Id]
    rep_ids', [Bind Id] -> CoreExpr -> CoreExpr
    forall b. [Bind b] -> Expr b -> Expr b
    mkLets [Bind Id]
    binds CoreExpr
    body)

        mk_default :: MatchResult (Maybe CoreAlt)
        mk_default :: MatchResult (Maybe (Alt Id))
    mk_default
          | Bool
    exhaustive_case = DsM (Maybe (Alt Id)) -> MatchResult (Maybe (Alt Id))
    forall a. DsM a -> MatchResult a
    MR_Infallible (DsM (Maybe (Alt Id)) -> MatchResult (Maybe (Alt Id)))
    -> DsM (Maybe (Alt Id)) -> MatchResult (Maybe (Alt Id))
    forall a b. (a -> b) -> a -> b
    $ Maybe (Alt Id) -> DsM (Maybe (Alt Id))
    forall (m :: * -> *) a. Monad m => a -> m a
    return Maybe (Alt Id)
    forall a. Maybe a
    Nothing
          | Bool
    otherwise       = (CoreExpr -> DsM (Maybe (Alt Id))) -> MatchResult (Maybe (Alt Id))
    forall a. (CoreExpr -> DsM a) -> MatchResult a
    MR_Fallible ((CoreExpr -> DsM (Maybe (Alt Id)))
     -> MatchResult (Maybe (Alt Id)))
    -> (CoreExpr -> DsM (Maybe (Alt Id)))
    -> MatchResult (Maybe (Alt Id))
    forall a b. (a -> b) -> a -> b
    $ \CoreExpr
    fail -> Maybe (Alt Id) -> DsM (Maybe (Alt Id))
    forall (m :: * -> *) a. Monad m => a -> m a
    return (Maybe (Alt Id) -> DsM (Maybe (Alt Id)))
    -> Maybe (Alt Id) -> DsM (Maybe (Alt Id))
    forall a b. (a -> b) -> a -> b
    $ Alt Id -> Maybe (Alt Id)
    forall a. a -> Maybe a
    Just (AltCon
    DEFAULT, [], CoreExpr
    fail)

        mentioned_constructors :: UniqSet DataCon
    mentioned_constructors = [DataCon] -> UniqSet DataCon
    forall a. Uniquable a => [a] -> UniqSet a
    mkUniqSet ([DataCon] -> UniqSet DataCon) -> [DataCon] -> UniqSet DataCon
    forall a b. (a -> b) -> a -> b
    $ (CaseAlt DataCon -> DataCon) -> [CaseAlt DataCon] -> [DataCon]
    forall a b. (a -> b) -> [a] -> [b]
    map CaseAlt DataCon -> DataCon
    forall a. CaseAlt a -> a
    alt_pat [CaseAlt DataCon]
    sorted_alts
        un_mentioned_constructors :: UniqSet DataCon
    un_mentioned_constructors
            = [DataCon] -> UniqSet DataCon
    forall a. Uniquable a => [a] -> UniqSet a
    mkUniqSet [DataCon]
    data_cons UniqSet DataCon -> UniqSet DataCon -> UniqSet DataCon
    forall a. UniqSet a -> UniqSet a -> UniqSet a
    `minusUniqSet` UniqSet DataCon
    mentioned_constructors
        exhaustive_case :: Bool
    exhaustive_case = UniqSet DataCon -> Bool
    forall a. UniqSet a -> Bool
    isEmptyUniqSet UniqSet DataCon
    un_mentioned_constructors

    {-
    ************************************************************************
    *                                                                      *
    \subsection{Desugarer's versions of some Core functions}
    *                                                                      *
    ************************************************************************
    -}

    mkErrorAppDs :: Id              -- The error function
                 -> Type            -- Type to which it should be applied
                 -> SDoc            -- The error message string to pass
                 -> DsM CoreExpr

    mkErrorAppDs :: Id -> Mult -> SDoc -> DsM CoreExpr
    mkErrorAppDs Id
    err_id Mult
    ty SDoc
    msg = do
        SrcSpan
    src_loc <- DsM SrcSpan
    getSrcSpanDs
        DynFlags
    dflags <- IOEnv (Env DsGblEnv DsLclEnv) DynFlags
    forall (m :: * -> *). HasDynFlags m => m DynFlags
    getDynFlags
        let
            full_msg :: String
    full_msg = DynFlags -> SDoc -> String
    showSDoc DynFlags
    dflags ([SDoc] -> SDoc
    hcat [SrcSpan -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr SrcSpan
    src_loc, SDoc
    vbar, SDoc
    msg])
            core_msg :: CoreExpr
    core_msg = Literal -> CoreExpr
    forall b. Literal -> Expr b
    Lit (String -> Literal
    mkLitString String
    full_msg)
            -- mkLitString returns a result of type String#
        CoreExpr -> DsM CoreExpr
    forall (m :: * -> *) a. Monad m => a -> m a
    return (CoreExpr -> [CoreExpr] -> CoreExpr
    forall b. Expr b -> [Expr b] -> Expr b
    mkApps (Id -> CoreExpr
    forall b. Id -> Expr b
    Var Id
    err_id) [Mult -> CoreExpr
    forall b. Mult -> Expr b
    Type (HasDebugCallStack => Mult -> Mult
    Mult -> Mult
    getRuntimeRep Mult
    ty), Mult -> CoreExpr
    forall b. Mult -> Expr b
    Type Mult
    ty, CoreExpr
    core_msg])

    {-
    'mkCoreAppDs' and 'mkCoreAppsDs' handle the special-case desugaring of 'seq'.

    Note [Desugaring seq]
    ~~~~~~~~~~~~~~~~~~~~~

    There are a few subtleties in the desugaring of `seq`:

     1. (as described in #1031)

        Consider,
           f x y = x `seq` (y `seq` (# x,y #))

        The [Core let/app invariant] means that, other things being equal, because
        the argument to the outer 'seq' has an unlifted type, we'll use call-by-value thus:

           f x y = case (y `seq` (# x,y #)) of v -> x `seq` v

        But that is bad for two reasons:
          (a) we now evaluate y before x, and
          (b) we can't bind v to an unboxed pair

        Seq is very, very special!  So we recognise it right here, and desugar to
                case x of _ -> case y of _ -> (# x,y #)

     2. (as described in #2273)

        Consider
           let chp = case b of { True -> fst x; False -> 0 }
           in chp `seq` ...chp...
        Here the seq is designed to plug the space leak of retaining (snd x)
        for too long.

        If we rely on the ordinary inlining of seq, we'll get
           let chp = case b of { True -> fst x; False -> 0 }
           case chp of _ { I# -> ...chp... }

        But since chp is cheap, and the case is an alluring contet, we'll
        inline chp into the case scrutinee.  Now there is only one use of chp,
        so we'll inline a second copy.  Alas, we've now ruined the purpose of
        the seq, by re-introducing the space leak:
            case (case b of {True -> fst x; False -> 0}) of
              I# _ -> ...case b of {True -> fst x; False -> 0}...

        We can try to avoid doing this by ensuring that the binder-swap in the
        case happens, so we get his at an early stage:
           case chp of chp2 { I# -> ...chp2... }
        But this is fragile.  The real culprit is the source program.  Perhaps we
        should have said explicitly
           let !chp2 = chp in ...chp2...

        But that's painful.  So the code here does a little hack to make seq
        more robust: a saturated application of 'seq' is turned *directly* into
        the case expression, thus:
           x  `seq` e2 ==> case x of x -> e2    -- Note shadowing!
           e1 `seq` e2 ==> case x of _ -> e2

        So we desugar our example to:
           let chp = case b of { True -> fst x; False -> 0 }
           case chp of chp { I# -> ...chp... }
        And now all is well.

        The reason it's a hack is because if you define mySeq=seq, the hack
        won't work on mySeq.

     3. (as described in #2409)

        The isLocalId ensures that we don't turn
                True `seq` e
        into
                case True of True { ... }
        which stupidly tries to bind the datacon 'True'.
    -}

    -- NB: Make sure the argument is not levity polymorphic
    mkCoreAppDs  :: SDoc -> CoreExpr -> CoreExpr -> CoreExpr
    mkCoreAppDs :: SDoc -> CoreExpr -> CoreExpr -> CoreExpr
    mkCoreAppDs SDoc
    _ (Var Id
    f `App` Type Mult
    _r `App` Type Mult
    ty1 `App` Type Mult
    ty2 `App` CoreExpr
    arg1) CoreExpr
    arg2
      | Id
    f Id -> Unique -> Bool
    forall a. Uniquable a => a -> Unique -> Bool
    `hasKey` Unique
    seqIdKey            -- Note [Desugaring seq], points (1) and (2)
      = CoreExpr -> Id -> Mult -> [Alt Id] -> CoreExpr
    forall b. Expr b -> b -> Mult -> [Alt b] -> Expr b
    Case CoreExpr
    arg1 Id
    case_bndr Mult
    ty2 [(AltCon
    DEFAULT,[],CoreExpr
    arg2)]
      where
        case_bndr :: Id
    case_bndr = case CoreExpr
    arg1 of
                       Var Id
    v1 | Name -> Bool
    isInternalName (Id -> Name
    idName Id
    v1)
                              -> Id
    v1        -- Note [Desugaring seq], points (2) and (3)
                       CoreExpr
    _      -> Mult -> Mult -> Id
    mkWildValBinder Mult
    Many Mult
    ty1

    mkCoreAppDs SDoc
    s CoreExpr
    fun CoreExpr
    arg = SDoc -> CoreExpr -> CoreExpr -> CoreExpr
    mkCoreApp SDoc
    s CoreExpr
    fun CoreExpr
    arg  -- The rest is done in GHC.Core.Make

    -- NB: No argument can be levity polymorphic
    mkCoreAppsDs :: SDoc -> CoreExpr -> [CoreExpr] -> CoreExpr
    mkCoreAppsDs :: SDoc -> CoreExpr -> [CoreExpr] -> CoreExpr
    mkCoreAppsDs SDoc
    s CoreExpr
    fun [CoreExpr]
    args = (CoreExpr -> CoreExpr -> CoreExpr)
    -> CoreExpr -> [CoreExpr] -> CoreExpr
    forall (t :: * -> *) b a.
    Foldable t =>
    (b -> a -> b) -> b -> t a -> b
    foldl' (SDoc -> CoreExpr -> CoreExpr -> CoreExpr
    mkCoreAppDs SDoc
    s) CoreExpr
    fun [CoreExpr]
    args

    mkCastDs :: CoreExpr -> Coercion -> CoreExpr
    -- We define a desugarer-specific version of GHC.Core.Utils.mkCast,
    -- because in the immediate output of the desugarer, we can have
    -- apparently-mis-matched coercions:  E.g.
    --     let a = b
    --     in (x :: a) |> (co :: b ~ Int)
    -- Lint know about type-bindings for let and does not complain
    -- So here we do not make the assertion checks that we make in
    -- GHC.Core.Utils.mkCast; and we do less peephole optimisation too
    mkCastDs :: CoreExpr -> Coercion -> CoreExpr
    mkCastDs CoreExpr
    e Coercion
    co | Coercion -> Bool
    isReflCo Coercion
    co = CoreExpr
    e
                  | Bool
    otherwise   = CoreExpr -> Coercion -> CoreExpr
    forall b. Expr b -> Coercion -> Expr b
    Cast CoreExpr
    e Coercion
    co

    {-
    ************************************************************************
    *                                                                      *
                   Tuples and selector bindings
    *                                                                      *
    ************************************************************************

    This is used in various places to do with lazy patterns.
    For each binder $b$ in the pattern, we create a binding:
    \begin{verbatim}
        b = case v of pat' -> b'
    \end{verbatim}
    where @pat'@ is @pat@ with each binder @b@ cloned into @b'@.

    ToDo: making these bindings should really depend on whether there's
    much work to be done per binding.  If the pattern is complex, it
    should be de-mangled once, into a tuple (and then selected from).
    Otherwise the demangling can be in-line in the bindings (as here).

    Boring!  Boring!  One error message per binder.  The above ToDo is
    even more helpful.  Something very similar happens for pattern-bound
    expressions.

    Note [mkSelectorBinds]
    ~~~~~~~~~~~~~~~~~~~~~~
    mkSelectorBinds is used to desugar a pattern binding {p = e},
    in a binding group:
      let { ...; p = e; ... } in body
    where p binds x,y (this list of binders can be empty).
    There are two cases.

    ------ Special case (A) -------
      For a pattern that is just a variable,
         let !x = e in body
      ==>
         let x = e in x `seq` body
      So we return the binding, with 'x' as the variable to seq.

    ------ Special case (B) -------
      For a pattern that is essentially just a tuple:
          * A product type, so cannot fail
          * Only one level, so that
              - generating multiple matches is fine
              - seq'ing it evaluates the same as matching it
      Then instead we generate
           { v = e
           ; x = case v of p -> x
           ; y = case v of p -> y }
      with 'v' as the variable to force

    ------ General case (C) -------
      In the general case we generate these bindings:
           let { ...; p = e; ... } in body
      ==>
           let { t = case e of p -> (x,y)
               ; x = case t of (x,y) -> x
               ; y = case t of (x,y) -> y }
           in t `seq` body

      Note that we return 't' as the variable to force if the pattern
      is strict (i.e. with -XStrict or an outermost-bang-pattern)

      Note that (A) /includes/ the situation where

       * The pattern binds exactly one variable
            let !(Just (Just x) = e in body
         ==>
           let { t = case e of Just (Just v) -> Solo v
               ; v = case t of Solo v -> v }
           in t `seq` body
        The 'Solo' is a one-tuple; see Note [One-tuples] in GHC.Builtin.Types
        Note that forcing 't' makes the pattern match happen,
        but does not force 'v'.

      * The pattern binds no variables
            let !(True,False) = e in body
        ==>
            let t = case e of (True,False) -> ()
            in t `seq` body

    ------ Examples ----------
      *   !(_, (_, a)) = e
        ==>
          t = case e of (_, (_, a)) -> Solo a
          a = case t of Solo a -> a

        Note that
         - Forcing 't' will force the pattern to match fully;
           e.g. will diverge if (snd e) is bottom
         - But 'a' itself is not forced; it is wrapped in a one-tuple
           (see Note [One-tuples] in GHC.Builtin.Types)

      *   !(Just x) = e
        ==>
          t = case e of Just x -> Solo x
          x = case t of Solo x -> x

        Again, forcing 't' will fail if 'e' yields Nothing.

    Note that even though this is rather general, the special cases
    work out well:

    * One binder, not -XStrict:

        let Just (Just v) = e in body
      ==>
        let t = case e of Just (Just v) -> Solo v
            v = case t of Solo v -> v
        in body
      ==>
        let v = case (case e of Just (Just v) -> Solo v) of
                  Solo v -> v
        in body
      ==>
        let v = case e of Just (Just v) -> v
        in body

    * Non-recursive, -XStrict
         let p = e in body
      ==>
         let { t = case e of p -> (x,y)
             ; x = case t of (x,y) -> x
             ; y = case t of (x,y) -> x }
         in t `seq` body
      ==> {inline seq, float x,y bindings inwards}
         let t = case e of p -> (x,y) in
         case t of t' ->
         let { x = case t' of (x,y) -> x
             ; y = case t' of (x,y) -> x } in
         body
      ==> {inline t, do case of case}
         case e of p ->
         let t = (x,y) in
         let { x = case t' of (x,y) -> x
             ; y = case t' of (x,y) -> x } in
         body
      ==> {case-cancellation, drop dead code}
         case e of p -> body

    * Special case (B) is there to avoid fruitlessly taking the tuple
      apart and rebuilding it. For example, consider
         { K x y = e }
      where K is a product constructor.  Then general case (A) does:
         { t = case e of K x y -> (x,y)
         ; x = case t of (x,y) -> x
         ; y = case t of (x,y) -> y }
      In the lazy case we can't optimise out this fruitless taking apart
      and rebuilding.  Instead (B) builds
         { v = e
         ; x = case v of K x y -> x
         ; y = case v of K x y -> y }
      which is better.
    -}
    -- Remark: pattern selectors only occur in unrestricted patterns so we are free
    -- to select Many as the multiplicity of every let-expression introduced.
    mkSelectorBinds :: [[Tickish Id]] -- ^ ticks to add, possibly
                    -> LPat GhcTc     -- ^ The pattern
                    -> CoreExpr       -- ^ Expression to which the pattern is bound
                    -> DsM (Id,[(Id,CoreExpr)])
                    -- ^ Id the rhs is bound to, for desugaring strict
                    -- binds (see Note [Desugar Strict binds] in "GHC.HsToCore.Binds")
                    -- and all the desugared binds

    mkSelectorBinds :: [[Tickish Id]]
    -> XRec (GhcPass 'Typechecked) Pat
    -> CoreExpr
    -> DsM (Id, [(Id, CoreExpr)])
    mkSelectorBinds [[Tickish Id]]
    ticks XRec (GhcPass 'Typechecked) Pat
    pat CoreExpr
    val_expr
      | L SrcSpan
    _ (VarPat XVarPat (GhcPass 'Typechecked)
    _ (L SrcSpan
    _ IdP (GhcPass 'Typechecked)
    v)) <- XRec (GhcPass 'Typechecked) Pat
    pat'     -- Special case (A)
      = (Id, [(Id, CoreExpr)]) -> DsM (Id, [(Id, CoreExpr)])
    forall (m :: * -> *) a. Monad m => a -> m a
    return (Id
    IdP (GhcPass 'Typechecked)
    v, [(Id
    IdP (GhcPass 'Typechecked)
    v, CoreExpr
    val_expr)])

      | XRec (GhcPass 'Typechecked) Pat -> Bool
    is_flat_prod_lpat XRec (GhcPass 'Typechecked) Pat
    pat'           -- Special case (B)
      = do { let pat_ty :: Mult
    pat_ty = XRec (GhcPass 'Typechecked) Pat -> Mult
    hsLPatType XRec (GhcPass 'Typechecked) Pat
    pat'
           ; Id
    val_var <- Mult -> Mult -> DsM Id
    newSysLocalDsNoLP Mult
    Many Mult
    pat_ty

           ; let mk_bind :: [Tickish Id] -> Id -> IOEnv (Env DsGblEnv DsLclEnv) (Id, CoreExpr)
    mk_bind [Tickish Id]
    tick Id
    bndr_var
                   -- (mk_bind sv bv)  generates  bv = case sv of { pat -> bv }
                   -- Remember, 'pat' binds 'bv'
                   = do { CoreExpr
    rhs_expr <- CoreExpr
    -> HsMatchContext GhcRn
    -> XRec (GhcPass 'Typechecked) Pat
    -> CoreExpr
    -> CoreExpr
    -> DsM CoreExpr
    matchSimply (Id -> CoreExpr
    forall b. Id -> Expr b
    Var Id
    val_var) HsMatchContext GhcRn
    forall p. HsMatchContext p
    PatBindRhs XRec (GhcPass 'Typechecked) Pat
    pat'
                                           (Id -> CoreExpr
    forall b. Id -> Expr b
    Var Id
    bndr_var)
                                           (Id -> CoreExpr
    forall b. Id -> Expr b
    Var Id
    bndr_var)  -- Neat hack
                          -- Neat hack: since 'pat' can't fail, the
                          -- "fail-expr" passed to matchSimply is not
                          -- used. But it /is/ used for its type, and for
                          -- that bndr_var is just the ticket.
                        ; (Id, CoreExpr) -> IOEnv (Env DsGblEnv DsLclEnv) (Id, CoreExpr)
    forall (m :: * -> *) a. Monad m => a -> m a
    return (Id
    bndr_var, [Tickish Id] -> CoreExpr -> CoreExpr
    mkOptTickBox [Tickish Id]
    tick CoreExpr
    rhs_expr) }

           ; [(Id, CoreExpr)]
    binds <- ([Tickish Id]
     -> Id -> IOEnv (Env DsGblEnv DsLclEnv) (Id, CoreExpr))
    -> [[Tickish Id]]
    -> [Id]
    -> IOEnv (Env DsGblEnv DsLclEnv) [(Id, CoreExpr)]
    forall (m :: * -> *) a b c.
    Applicative m =>
    (a -> b -> m c) -> [a] -> [b] -> m [c]
    zipWithM [Tickish Id] -> Id -> IOEnv (Env DsGblEnv DsLclEnv) (Id, CoreExpr)
    mk_bind [[Tickish Id]]
    ticks' [Id]
    [IdP (GhcPass 'Typechecked)]
    binders
           ; (Id, [(Id, CoreExpr)]) -> DsM (Id, [(Id, CoreExpr)])
    forall (m :: * -> *) a. Monad m => a -> m a
    return ( Id
    val_var, (Id
    val_var, CoreExpr
    val_expr) (Id, CoreExpr) -> [(Id, CoreExpr)] -> [(Id, CoreExpr)]
    forall a. a -> [a] -> [a]
    : [(Id, CoreExpr)]
    binds) }

      | Bool
    otherwise                          -- General case (C)
      = do { Id
    tuple_var  <- Mult -> Mult -> DsM Id
    newSysLocalDs Mult
    Many Mult
    tuple_ty
           ; CoreExpr
    error_expr <- Id -> Mult -> SDoc -> DsM CoreExpr
    mkErrorAppDs Id
    pAT_ERROR_ID Mult
    tuple_ty (GenLocated SrcSpan (Pat (GhcPass 'Typechecked)) -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr GenLocated SrcSpan (Pat (GhcPass 'Typechecked))
    XRec (GhcPass 'Typechecked) Pat
    pat')
           ; CoreExpr
    tuple_expr <- CoreExpr
    -> HsMatchContext GhcRn
    -> XRec (GhcPass 'Typechecked) Pat
    -> CoreExpr
    -> CoreExpr
    -> DsM CoreExpr
    matchSimply CoreExpr
    val_expr HsMatchContext GhcRn
    forall p. HsMatchContext p
    PatBindRhs XRec (GhcPass 'Typechecked) Pat
    pat
                                       CoreExpr
    local_tuple CoreExpr
    error_expr
           ; let mk_tup_bind :: [Tickish Id] -> Id -> (Id, CoreExpr)
    mk_tup_bind [Tickish Id]
    tick Id
    binder
                   = (Id
    binder, [Tickish Id] -> CoreExpr -> CoreExpr
    mkOptTickBox [Tickish Id]
    tick (CoreExpr -> CoreExpr) -> CoreExpr -> CoreExpr
    forall a b. (a -> b) -> a -> b
    $
                              [Id] -> Id -> Id -> CoreExpr -> CoreExpr
    mkTupleSelector1 [Id]
    local_binders Id
    binder
                                               Id
    tuple_var (Id -> CoreExpr
    forall b. Id -> Expr b
    Var Id
    tuple_var))
                 tup_binds :: [(Id, CoreExpr)]
    tup_binds = ([Tickish Id] -> Id -> (Id, CoreExpr))
    -> [[Tickish Id]] -> [Id] -> [(Id, CoreExpr)]
    forall a b c. (a -> b -> c) -> [a] -> [b] -> [c]
    zipWith [Tickish Id] -> Id -> (Id, CoreExpr)
    mk_tup_bind [[Tickish Id]]
    ticks' [Id]
    [IdP (GhcPass 'Typechecked)]
    binders
           ; (Id, [(Id, CoreExpr)]) -> DsM (Id, [(Id, CoreExpr)])
    forall (m :: * -> *) a. Monad m => a -> m a
    return (Id
    tuple_var, (Id
    tuple_var, CoreExpr
    tuple_expr) (Id, CoreExpr) -> [(Id, CoreExpr)] -> [(Id, CoreExpr)]
    forall a. a -> [a] -> [a]
    : [(Id, CoreExpr)]
    tup_binds) }
      where
        pat' :: XRec (GhcPass 'Typechecked) Pat
    pat' = XRec (GhcPass 'Typechecked) Pat -> XRec (GhcPass 'Typechecked) Pat
    forall (p :: Pass). LPat (GhcPass p) -> LPat (GhcPass p)
    strip_bangs XRec (GhcPass 'Typechecked) Pat
    pat
               -- Strip the bangs before looking for case (A) or (B)
               -- The incoming pattern may well have a bang on it

        binders :: [IdP (GhcPass 'Typechecked)]
    binders = XRec (GhcPass 'Typechecked) Pat -> [IdP (GhcPass 'Typechecked)]
    forall p. CollectPass p => LPat p -> [IdP p]
    collectPatBinders XRec (GhcPass 'Typechecked) Pat
    pat'
        ticks' :: [[Tickish Id]]
    ticks'  = [[Tickish Id]]
    ticks [[Tickish Id]] -> [[Tickish Id]] -> [[Tickish Id]]
    forall a. [a] -> [a] -> [a]
    ++ [Tickish Id] -> [[Tickish Id]]
    forall a. a -> [a]
    repeat []

        local_binders :: [Id]
    local_binders = (Id -> Id) -> [Id] -> [Id]
    forall a b. (a -> b) -> [a] -> [b]
    map Id -> Id
    localiseId [Id]
    [IdP (GhcPass 'Typechecked)]
    binders      -- See Note [Localise pattern binders]
        local_tuple :: CoreExpr
    local_tuple   = [Id] -> CoreExpr
    mkBigCoreVarTup1 [Id]
    [IdP (GhcPass 'Typechecked)]
    binders
        tuple_ty :: Mult
    tuple_ty      = CoreExpr -> Mult
    exprType CoreExpr
    local_tuple

    strip_bangs :: LPat (GhcPass p) -> LPat (GhcPass p)
    -- Remove outermost bangs and parens
    strip_bangs :: forall (p :: Pass). LPat (GhcPass p) -> LPat (GhcPass p)
    strip_bangs (L SrcSpan
    _ (ParPat XParPat (GhcPass p)
    _ LPat (GhcPass p)
    p))  = LPat (GhcPass p) -> LPat (GhcPass p)
    forall (p :: Pass). LPat (GhcPass p) -> LPat (GhcPass p)
    strip_bangs LPat (GhcPass p)
    p
    strip_bangs (L SrcSpan
    _ (BangPat XBangPat (GhcPass p)
    _ LPat (GhcPass p)
    p)) = LPat (GhcPass p) -> LPat (GhcPass p)
    forall (p :: Pass). LPat (GhcPass p) -> LPat (GhcPass p)
    strip_bangs LPat (GhcPass p)
    p
    strip_bangs LPat (GhcPass p)
    lp                  = LPat (GhcPass p)
    lp

    is_flat_prod_lpat :: LPat GhcTc -> Bool
    is_flat_prod_lpat :: XRec (GhcPass 'Typechecked) Pat -> Bool
    is_flat_prod_lpat = Pat (GhcPass 'Typechecked) -> Bool
    is_flat_prod_pat (Pat (GhcPass 'Typechecked) -> Bool)
    -> (GenLocated SrcSpan (Pat (GhcPass 'Typechecked))
        -> Pat (GhcPass 'Typechecked))
    -> GenLocated SrcSpan (Pat (GhcPass 'Typechecked))
    -> Bool
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . GenLocated SrcSpan (Pat (GhcPass 'Typechecked))
    -> Pat (GhcPass 'Typechecked)
    forall l e. GenLocated l e -> e
    unLoc

    is_flat_prod_pat :: Pat GhcTc -> Bool
    is_flat_prod_pat :: Pat (GhcPass 'Typechecked) -> Bool
    is_flat_prod_pat (ParPat XParPat (GhcPass 'Typechecked)
    _ XRec (GhcPass 'Typechecked) Pat
    p)          = XRec (GhcPass 'Typechecked) Pat -> Bool
    is_flat_prod_lpat XRec (GhcPass 'Typechecked) Pat
    p
    is_flat_prod_pat (TuplePat XTuplePat (GhcPass 'Typechecked)
    _ [XRec (GhcPass 'Typechecked) Pat]
    ps Boxity
    Boxed) = (GenLocated SrcSpan (Pat (GhcPass 'Typechecked)) -> Bool)
    -> [GenLocated SrcSpan (Pat (GhcPass 'Typechecked))] -> Bool
    forall (t :: * -> *) a. Foldable t => (a -> Bool) -> t a -> Bool
    all GenLocated SrcSpan (Pat (GhcPass 'Typechecked)) -> Bool
    forall (p :: Pass). LPat (GhcPass p) -> Bool
    is_triv_lpat [GenLocated SrcSpan (Pat (GhcPass 'Typechecked))]
    [XRec (GhcPass 'Typechecked) Pat]
    ps
    is_flat_prod_pat (ConPat { pat_con :: forall p. Pat p -> Located (ConLikeP p)
    pat_con  = L SrcSpan
    _ ConLikeP (GhcPass 'Typechecked)
    pcon
                             , pat_args :: forall p. Pat p -> HsConPatDetails p
    pat_args = HsConPatDetails (GhcPass 'Typechecked)
    ps})
      | RealDataCon DataCon
    con <- ConLikeP (GhcPass 'Typechecked)
    pcon
      , TyCon -> Bool
    isProductTyCon (DataCon -> TyCon
    dataConTyCon DataCon
    con)
      = (GenLocated SrcSpan (Pat (GhcPass 'Typechecked)) -> Bool)
    -> [GenLocated SrcSpan (Pat (GhcPass 'Typechecked))] -> Bool
    forall (t :: * -> *) a. Foldable t => (a -> Bool) -> t a -> Bool
    all GenLocated SrcSpan (Pat (GhcPass 'Typechecked)) -> Bool
    forall (p :: Pass). LPat (GhcPass p) -> Bool
    is_triv_lpat (HsConPatDetails (GhcPass 'Typechecked)
    -> [XRec (GhcPass 'Typechecked) Pat]
    forall p. HsConPatDetails p -> [LPat p]
    hsConPatArgs HsConPatDetails (GhcPass 'Typechecked)
    ps)
    is_flat_prod_pat Pat (GhcPass 'Typechecked)
    _ = Bool
    False

    is_triv_lpat :: LPat (GhcPass p) -> Bool
    is_triv_lpat :: forall (p :: Pass). LPat (GhcPass p) -> Bool
    is_triv_lpat = Pat (GhcPass p) -> Bool
    forall (p :: Pass). Pat (GhcPass p) -> Bool
    is_triv_pat (Pat (GhcPass p) -> Bool)
    -> (GenLocated SrcSpan (Pat (GhcPass p)) -> Pat (GhcPass p))
    -> GenLocated SrcSpan (Pat (GhcPass p))
    -> Bool
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . GenLocated SrcSpan (Pat (GhcPass p)) -> Pat (GhcPass p)
    forall l e. GenLocated l e -> e
    unLoc

    is_triv_pat :: Pat (GhcPass p) -> Bool
    is_triv_pat :: forall (p :: Pass). Pat (GhcPass p) -> Bool
    is_triv_pat (VarPat {})  = Bool
    True
    is_triv_pat (WildPat{})  = Bool
    True
    is_triv_pat (ParPat XParPat (GhcPass p)
    _ LPat (GhcPass p)
    p) = LPat (GhcPass p) -> Bool
    forall (p :: Pass). LPat (GhcPass p) -> Bool
    is_triv_lpat LPat (GhcPass p)
    p
    is_triv_pat Pat (GhcPass p)
    _            = Bool
    False

    {- *********************************************************************
    *                                                                      *
      Creating big tuples and their types for full Haskell expressions.
      They work over *Ids*, and create tuples replete with their types,
      which is whey they are not in GHC.Hs.Utils.
    *                                                                      *
    ********************************************************************* -}

    mkLHsPatTup :: [LPat GhcTc] -> LPat GhcTc
    mkLHsPatTup :: [XRec (GhcPass 'Typechecked) Pat]
    -> XRec (GhcPass 'Typechecked) Pat
    mkLHsPatTup []     = Pat (GhcPass 'Typechecked)
    -> GenLocated SrcSpan (Pat (GhcPass 'Typechecked))
    forall e. e -> Located e
    noLoc (Pat (GhcPass 'Typechecked)
     -> GenLocated SrcSpan (Pat (GhcPass 'Typechecked)))
    -> Pat (GhcPass 'Typechecked)
    -> GenLocated SrcSpan (Pat (GhcPass 'Typechecked))
    forall a b. (a -> b) -> a -> b
    $ [XRec (GhcPass 'Typechecked) Pat]
    -> Boxity -> Pat (GhcPass 'Typechecked)
    mkVanillaTuplePat [] Boxity
    Boxed
    mkLHsPatTup [XRec (GhcPass 'Typechecked) Pat
    lpat] = XRec (GhcPass 'Typechecked) Pat
    lpat
    mkLHsPatTup [XRec (GhcPass 'Typechecked) Pat]
    lpats  = SrcSpan
    -> Pat (GhcPass 'Typechecked)
    -> GenLocated SrcSpan (Pat (GhcPass 'Typechecked))
    forall l e. l -> e -> GenLocated l e
    L (GenLocated SrcSpan (Pat (GhcPass 'Typechecked)) -> SrcSpan
    forall l e. GenLocated l e -> l
    getLoc ([GenLocated SrcSpan (Pat (GhcPass 'Typechecked))]
    -> GenLocated SrcSpan (Pat (GhcPass 'Typechecked))
    forall a. [a] -> a
    head [GenLocated SrcSpan (Pat (GhcPass 'Typechecked))]
    [XRec (GhcPass 'Typechecked) Pat]
    lpats)) (Pat (GhcPass 'Typechecked)
     -> GenLocated SrcSpan (Pat (GhcPass 'Typechecked)))
    -> Pat (GhcPass 'Typechecked)
    -> GenLocated SrcSpan (Pat (GhcPass 'Typechecked))
    forall a b. (a -> b) -> a -> b
    $
                         [XRec (GhcPass 'Typechecked) Pat]
    -> Boxity -> Pat (GhcPass 'Typechecked)
    mkVanillaTuplePat [XRec (GhcPass 'Typechecked) Pat]
    lpats Boxity
    Boxed

    mkVanillaTuplePat :: [LPat GhcTc] -> Boxity -> Pat GhcTc
    -- A vanilla tuple pattern simply gets its type from its sub-patterns
    mkVanillaTuplePat :: [XRec (GhcPass 'Typechecked) Pat]
    -> Boxity -> Pat (GhcPass 'Typechecked)
    mkVanillaTuplePat [XRec (GhcPass 'Typechecked) Pat]
    pats Boxity
    box = XTuplePat (GhcPass 'Typechecked)
    -> [XRec (GhcPass 'Typechecked) Pat]
    -> Boxity
    -> Pat (GhcPass 'Typechecked)
    forall p. XTuplePat p -> [LPat p] -> Boxity -> Pat p
    TuplePat ((GenLocated SrcSpan (Pat (GhcPass 'Typechecked)) -> Mult)
    -> [GenLocated SrcSpan (Pat (GhcPass 'Typechecked))] -> [Mult]
    forall a b. (a -> b) -> [a] -> [b]
    map GenLocated SrcSpan (Pat (GhcPass 'Typechecked)) -> Mult
    XRec (GhcPass 'Typechecked) Pat -> Mult
    hsLPatType [GenLocated SrcSpan (Pat (GhcPass 'Typechecked))]
    [XRec (GhcPass 'Typechecked) Pat]
    pats) [XRec (GhcPass 'Typechecked) Pat]
    pats Boxity
    box

    -- The Big equivalents for the source tuple expressions
    mkBigLHsVarTupId :: [Id] -> LHsExpr GhcTc
    mkBigLHsVarTupId :: [Id] -> LHsExpr (GhcPass 'Typechecked)
    mkBigLHsVarTupId [Id]
    ids = [LHsExpr (GhcPass 'Typechecked)] -> LHsExpr (GhcPass 'Typechecked)
    mkBigLHsTupId ((Id -> LHsExpr (GhcPass 'Typechecked))
    -> [Id] -> [LHsExpr (GhcPass 'Typechecked)]
    forall a b. (a -> b) -> [a] -> [b]
    map Id -> LHsExpr (GhcPass 'Typechecked)
    forall (id :: Pass). IdP (GhcPass id) -> LHsExpr (GhcPass id)
    nlHsVar [Id]
    ids)

    mkBigLHsTupId :: [LHsExpr GhcTc] -> LHsExpr GhcTc
    mkBigLHsTupId :: [LHsExpr (GhcPass 'Typechecked)] -> LHsExpr (GhcPass 'Typechecked)
    mkBigLHsTupId = ([LHsExpr (GhcPass 'Typechecked)]
     -> LHsExpr (GhcPass 'Typechecked))
    -> [LHsExpr (GhcPass 'Typechecked)]
    -> LHsExpr (GhcPass 'Typechecked)
    forall a. ([a] -> a) -> [a] -> a
    mkChunkified [LHsExpr (GhcPass 'Typechecked)] -> LHsExpr (GhcPass 'Typechecked)
    forall (a :: Pass). [LHsExpr (GhcPass a)] -> LHsExpr (GhcPass a)
    mkLHsTupleExpr

    -- The Big equivalents for the source tuple patterns
    mkBigLHsVarPatTupId :: [Id] -> LPat GhcTc
    mkBigLHsVarPatTupId :: [Id] -> XRec (GhcPass 'Typechecked) Pat
    mkBigLHsVarPatTupId [Id]
    bs = [XRec (GhcPass 'Typechecked) Pat]
    -> XRec (GhcPass 'Typechecked) Pat
    mkBigLHsPatTupId ((Id -> GenLocated SrcSpan (Pat (GhcPass 'Typechecked)))
    -> [Id] -> [GenLocated SrcSpan (Pat (GhcPass 'Typechecked))]
    forall a b. (a -> b) -> [a] -> [b]
    map Id -> GenLocated SrcSpan (Pat (GhcPass 'Typechecked))
    forall (id :: Pass). IdP (GhcPass id) -> LPat (GhcPass id)
    nlVarPat [Id]
    bs)

    mkBigLHsPatTupId :: [LPat GhcTc] -> LPat GhcTc
    mkBigLHsPatTupId :: [XRec (GhcPass 'Typechecked) Pat]
    -> XRec (GhcPass 'Typechecked) Pat
    mkBigLHsPatTupId = ([GenLocated SrcSpan (Pat (GhcPass 'Typechecked))]
     -> GenLocated SrcSpan (Pat (GhcPass 'Typechecked)))
    -> [GenLocated SrcSpan (Pat (GhcPass 'Typechecked))]
    -> GenLocated SrcSpan (Pat (GhcPass 'Typechecked))
    forall a. ([a] -> a) -> [a] -> a
    mkChunkified [GenLocated SrcSpan (Pat (GhcPass 'Typechecked))]
    -> GenLocated SrcSpan (Pat (GhcPass 'Typechecked))
    [XRec (GhcPass 'Typechecked) Pat]
    -> XRec (GhcPass 'Typechecked) Pat
    mkLHsPatTup

    {-
    ************************************************************************
    *                                                                      *
            Code for pattern-matching and other failures
    *                                                                      *
    ************************************************************************

    Generally, we handle pattern matching failure like this: let-bind a
    fail-variable, and use that variable if the thing fails:
    \begin{verbatim}
            let fail.33 = error "Help"
            in
            case x of
                    p1 -> ...
                    p2 -> fail.33
                    p3 -> fail.33
                    p4 -> ...
    \end{verbatim}
    Then
    \begin{itemize}
    \item
    If the case can't fail, then there'll be no mention of @fail.33@, and the
    simplifier will later discard it.

    \item
    If it can fail in only one way, then the simplifier will inline it.

    \item
    Only if it is used more than once will the let-binding remain.
    \end{itemize}

    There's a problem when the result of the case expression is of
    unboxed type.  Then the type of @fail.33@ is unboxed too, and
    there is every chance that someone will change the let into a case:
    \begin{verbatim}
            case error "Help" of
              fail.33 -> case ....
    \end{verbatim}

    which is of course utterly wrong.  Rather than drop the condition that
    only boxed types can be let-bound, we just turn the fail into a function
    for the primitive case:
    \begin{verbatim}
            let fail.33 :: Void -> Int#
                fail.33 = \_ -> error "Help"
            in
            case x of
                    p1 -> ...
                    p2 -> fail.33 void
                    p3 -> fail.33 void
                    p4 -> ...
    \end{verbatim}

    Now @fail.33@ is a function, so it can be let-bound.

    We would *like* to use join points here; in fact, these "fail variables" are
    paradigmatic join points! Sadly, this breaks pattern synonyms, which desugar as
    CPS functions - i.e. they take "join points" as parameters. It's not impossible
    to imagine extending our type system to allow passing join points around (very
    carefully), but we certainly don't support it now.

    99.99% of the time, the fail variables wind up as join points in short order
    anyway, and the Void# doesn't do much harm.
    -}

    mkFailurePair :: CoreExpr       -- Result type of the whole case expression
                  -> DsM (CoreBind, -- Binds the newly-created fail variable
                                    -- to \ _ -> expression
                          CoreExpr) -- Fail variable applied to realWorld#
    -- See Note [Failure thunks and CPR]
    mkFailurePair :: CoreExpr -> DsM (Bind Id, CoreExpr)
    mkFailurePair CoreExpr
    expr
      = do { Id
    fail_fun_var <- Mult -> Mult -> DsM Id
    newFailLocalDs Mult
    Many (Mult
    voidPrimTy Mult -> Mult -> Mult
    `mkVisFunTyMany` Mult
    ty)
           ; Id
    fail_fun_arg <- Mult -> Mult -> DsM Id
    newSysLocalDs Mult
    Many Mult
    voidPrimTy
           ; let real_arg :: Id
    real_arg = Id -> Id
    setOneShotLambda Id
    fail_fun_arg
           ; (Bind Id, CoreExpr) -> DsM (Bind Id, CoreExpr)
    forall (m :: * -> *) a. Monad m => a -> m a
    return (Id -> CoreExpr -> Bind Id
    forall b. b -> Expr b -> Bind b
    NonRec Id
    fail_fun_var (Id -> CoreExpr -> CoreExpr
    forall b. b -> Expr b -> Expr b
    Lam Id
    real_arg CoreExpr
    expr),
                     CoreExpr -> CoreExpr -> CoreExpr
    forall b. Expr b -> Expr b -> Expr b
    App (Id -> CoreExpr
    forall b. Id -> Expr b
    Var Id
    fail_fun_var) (Id -> CoreExpr
    forall b. Id -> Expr b
    Var Id
    voidPrimId)) }
      where
        ty :: Mult
    ty = CoreExpr -> Mult
    exprType CoreExpr
    expr

    -- Uses '@mkFailurePair@' to bind the failure case. Infallible matches have
    -- neither a failure arg or failure "hole", so nothing is let-bound, and no
    -- extraneous Core is produced.
    shareFailureHandler :: MatchResult CoreExpr -> MatchResult CoreExpr
    shareFailureHandler :: MatchResult CoreExpr -> MatchResult CoreExpr
    shareFailureHandler = \case
      mr :: MatchResult CoreExpr
    mr@(MR_Infallible DsM CoreExpr
    _) -> MatchResult CoreExpr
    mr
      MR_Fallible CoreExpr -> DsM CoreExpr
    match_fn -> (CoreExpr -> DsM CoreExpr) -> MatchResult CoreExpr
    forall a. (CoreExpr -> DsM a) -> MatchResult a
    MR_Fallible ((CoreExpr -> DsM CoreExpr) -> MatchResult CoreExpr)
    -> (CoreExpr -> DsM CoreExpr) -> MatchResult CoreExpr
    forall a b. (a -> b) -> a -> b
    $ \CoreExpr
    fail_expr -> do
        (Bind Id
    fail_bind, CoreExpr
    shared_failure_handler) <- CoreExpr -> DsM (Bind Id, CoreExpr)
    mkFailurePair CoreExpr
    fail_expr
        CoreExpr
    body <- CoreExpr -> DsM CoreExpr
    match_fn CoreExpr
    shared_failure_handler
        -- Never unboxed, per the above, so always OK for `let` not `case`.
        CoreExpr -> DsM CoreExpr
    forall (m :: * -> *) a. Monad m => a -> m a
    return (CoreExpr -> DsM CoreExpr) -> CoreExpr -> DsM CoreExpr
    forall a b. (a -> b) -> a -> b
    $ Bind Id -> CoreExpr -> CoreExpr
    forall b. Bind b -> Expr b -> Expr b
    Let Bind Id
    fail_bind CoreExpr
    body

    {-
    Note [Failure thunks and CPR]
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    (This note predates join points as formal entities (hence the quotation marks).
    We can't use actual join points here (see above); if we did, this would also
    solve the CPR problem, since join points don't get CPR'd. See Note [Don't CPR
    join points] in GHC.Core.Opt.WorkWrap.)

    When we make a failure point we ensure that it
    does not look like a thunk. Example:

       let fail = \rw -> error "urk"
       in case x of
            [] -> fail realWorld#
            (y:ys) -> case ys of
                        [] -> fail realWorld#
                        (z:zs) -> (y,z)

    Reason: we know that a failure point is always a "join point" and is
    entered at most once.  Adding a dummy 'realWorld' token argument makes
    it clear that sharing is not an issue.  And that in turn makes it more
    CPR-friendly.  This matters a lot: if you don't get it right, you lose
    the tail call property.  For example, see #3403.

    ************************************************************************
    *                                                                      *
                  Ticks
    *                                                                      *
    ********************************************************************* -}

    mkOptTickBox :: [Tickish Id] -> CoreExpr -> CoreExpr
    mkOptTickBox :: [Tickish Id] -> CoreExpr -> CoreExpr
    mkOptTickBox = (CoreExpr -> [Tickish Id] -> CoreExpr)
    -> [Tickish Id] -> CoreExpr -> CoreExpr
    forall a b c. (a -> b -> c) -> b -> a -> c
    flip ((Tickish Id -> CoreExpr -> CoreExpr)
    -> CoreExpr -> [Tickish Id] -> CoreExpr
    forall (t :: * -> *) a b.
    Foldable t =>
    (a -> b -> b) -> b -> t a -> b
    foldr Tickish Id -> CoreExpr -> CoreExpr
    forall b. Tickish Id -> Expr b -> Expr b
    Tick)

    mkBinaryTickBox :: Int -> Int -> CoreExpr -> DsM CoreExpr
    mkBinaryTickBox :: ConTag -> ConTag -> CoreExpr -> DsM CoreExpr
    mkBinaryTickBox ConTag
    ixT ConTag
    ixF CoreExpr
    e = do
           Unique
    uq <- TcRnIf DsGblEnv DsLclEnv Unique
    forall gbl lcl. TcRnIf gbl lcl Unique
    newUnique
           Module
    this_mod <- IOEnv (Env DsGblEnv DsLclEnv) Module
    forall (m :: * -> *). HasModule m => m Module
    getModule
           let bndr1 :: Id
    bndr1 = FastString -> Unique -> Mult -> Mult -> Id
    mkSysLocal (String -> FastString
    fsLit String
    "t1") Unique
    uq Mult
    One Mult
    boolTy
             -- It's always sufficient to pattern-match on a boolean with
             -- multiplicity 'One'.
           let
               falseBox :: CoreExpr
    falseBox = Tickish Id -> CoreExpr -> CoreExpr
    forall b. Tickish Id -> Expr b -> Expr b
    Tick (Module -> ConTag -> Tickish Id
    forall id. Module -> ConTag -> Tickish id
    HpcTick Module
    this_mod ConTag
    ixF) (Id -> CoreExpr
    forall b. Id -> Expr b
    Var Id
    falseDataConId)
               trueBox :: CoreExpr
    trueBox  = Tickish Id -> CoreExpr -> CoreExpr
    forall b. Tickish Id -> Expr b -> Expr b
    Tick (Module -> ConTag -> Tickish Id
    forall id. Module -> ConTag -> Tickish id
    HpcTick Module
    this_mod ConTag
    ixT) (Id -> CoreExpr
    forall b. Id -> Expr b
    Var Id
    trueDataConId)
           --
           CoreExpr -> DsM CoreExpr
    forall (m :: * -> *) a. Monad m => a -> m a
    return (CoreExpr -> DsM CoreExpr) -> CoreExpr -> DsM CoreExpr
    forall a b. (a -> b) -> a -> b
    $ CoreExpr -> Id -> Mult -> [Alt Id] -> CoreExpr
    forall b. Expr b -> b -> Mult -> [Alt b] -> Expr b
    Case CoreExpr
    e Id
    bndr1 Mult
    boolTy
                           [ (DataCon -> AltCon
    DataAlt DataCon
    falseDataCon, [], CoreExpr
    falseBox)
                           , (DataCon -> AltCon
    DataAlt DataCon
    trueDataCon,  [], CoreExpr
    trueBox)
                           ]

    -- *******************************************************************

    {- Note [decideBangHood]
    ~~~~~~~~~~~~~~~~~~~~~~~~
    With -XStrict we may make /outermost/ patterns more strict.
    E.g.
           let (Just x) = e in ...
              ==>
           let !(Just x) = e in ...
    and
           f x = e
              ==>
           f !x = e

    This adjustment is done by decideBangHood,

      * Just before constructing an EqnInfo, in GHC.HsToCore.Match
          (matchWrapper and matchSinglePat)

      * When desugaring a pattern-binding in GHC.HsToCore.Binds.dsHsBind

    Note that it is /not/ done recursively.  See the -XStrict
    spec in the user manual.

    Specifically:
       ~pat    => pat    -- when -XStrict (even if pat = ~pat')
       !pat    => !pat   -- always
       pat     => !pat   -- when -XStrict
       pat     => pat    -- otherwise
    -}

    -- | Use -XStrict to add a ! or remove a ~
    -- See Note [decideBangHood]
    decideBangHood :: DynFlags
                   -> LPat GhcTc  -- ^ Original pattern
                   -> LPat GhcTc  -- Pattern with bang if necessary
    decideBangHood :: DynFlags
    -> XRec (GhcPass 'Typechecked) Pat
    -> XRec (GhcPass 'Typechecked) Pat
    decideBangHood DynFlags
    dflags XRec (GhcPass 'Typechecked) Pat
    lpat
      | Bool -> Bool
    not (Extension -> DynFlags -> Bool
    xopt Extension
    LangExt.Strict DynFlags
    dflags)
      = XRec (GhcPass 'Typechecked) Pat
    lpat
      | Bool
    otherwise   --  -XStrict
      = GenLocated SrcSpan (Pat (GhcPass 'Typechecked))
    -> GenLocated SrcSpan (Pat (GhcPass 'Typechecked))
    forall {p} {l}.
    (XRec p Pat ~ GenLocated l (Pat p), XBangPat p ~ NoExtField) =>
    GenLocated l (Pat p) -> GenLocated l (Pat p)
    go GenLocated SrcSpan (Pat (GhcPass 'Typechecked))
    XRec (GhcPass 'Typechecked) Pat
    lpat
      where
        go :: GenLocated l (Pat p) -> GenLocated l (Pat p)
    go lp :: GenLocated l (Pat p)
    lp@(L l
    l Pat p
    p)
          = case Pat p
    p of
               ParPat XParPat p
    x XRec p Pat
    p    -> l -> Pat p -> GenLocated l (Pat p)
    forall l e. l -> e -> GenLocated l e
    L l
    l (XParPat p -> XRec p Pat -> Pat p
    forall p. XParPat p -> LPat p -> Pat p
    ParPat XParPat p
    x (GenLocated l (Pat p) -> GenLocated l (Pat p)
    go GenLocated l (Pat p)
    XRec p Pat
    p))
               LazyPat XLazyPat p
    _ XRec p Pat
    lp' -> GenLocated l (Pat p)
    XRec p Pat
    lp'
               BangPat XBangPat p
    _ XRec p Pat
    _   -> GenLocated l (Pat p)
    lp
               Pat p
    _             -> l -> Pat p -> GenLocated l (Pat p)
    forall l e. l -> e -> GenLocated l e
    L l
    l (XBangPat p -> XRec p Pat -> Pat p
    forall p. XBangPat p -> LPat p -> Pat p
    BangPat NoExtField
    XBangPat p
    noExtField GenLocated l (Pat p)
    XRec p Pat
    lp)

    isTrueLHsExpr :: LHsExpr GhcTc -> Maybe (CoreExpr -> DsM CoreExpr)

    -- Returns Just {..} if we're sure that the expression is True
    -- I.e.   * 'True' datacon
    --        * 'otherwise' Id
    --        * Trivial wappings of these
    -- The arguments to Just are any HsTicks that we have found,
    -- because we still want to tick then, even it they are always evaluated.
    isTrueLHsExpr :: LHsExpr (GhcPass 'Typechecked) -> Maybe (CoreExpr -> DsM CoreExpr)
    isTrueLHsExpr (L SrcSpan
    _ (HsVar XVar (GhcPass 'Typechecked)
    _ (L SrcSpan
    _ IdP (GhcPass 'Typechecked)
    v)))
      |  Id
    IdP (GhcPass 'Typechecked)
    v Id -> Unique -> Bool
    forall a. Uniquable a => a -> Unique -> Bool
    `hasKey` Unique
    otherwiseIdKey
         Bool -> Bool -> Bool
    || Id
    IdP (GhcPass 'Typechecked)
    v Id -> Unique -> Bool
    forall a. Uniquable a => a -> Unique -> Bool
    `hasKey` Id -> Unique
    forall a. Uniquable a => a -> Unique
    getUnique Id
    trueDataConId
                                                  = (CoreExpr -> DsM CoreExpr) -> Maybe (CoreExpr -> DsM CoreExpr)
    forall a. a -> Maybe a
    Just CoreExpr -> DsM CoreExpr
    forall (m :: * -> *) a. Monad m => a -> m a
    return
            -- trueDataConId doesn't have the same unique as trueDataCon
    isTrueLHsExpr (L SrcSpan
    _ (HsConLikeOut XConLikeOut (GhcPass 'Typechecked)
    _ ConLike
    con))
      | ConLike
    con ConLike -> Unique -> Bool
    forall a. Uniquable a => a -> Unique -> Bool
    `hasKey` DataCon -> Unique
    forall a. Uniquable a => a -> Unique
    getUnique DataCon
    trueDataCon = (CoreExpr -> DsM CoreExpr) -> Maybe (CoreExpr -> DsM CoreExpr)
    forall a. a -> Maybe a
    Just CoreExpr -> DsM CoreExpr
    forall (m :: * -> *) a. Monad m => a -> m a
    return
    isTrueLHsExpr (L SrcSpan
    _ (HsTick XTick (GhcPass 'Typechecked)
    _ Tickish (IdP (GhcPass 'Typechecked))
    tickish LHsExpr (GhcPass 'Typechecked)
    e))
        | Just CoreExpr -> DsM CoreExpr
    ticks <- LHsExpr (GhcPass 'Typechecked) -> Maybe (CoreExpr -> DsM CoreExpr)
    isTrueLHsExpr LHsExpr (GhcPass 'Typechecked)
    e
        = (CoreExpr -> DsM CoreExpr) -> Maybe (CoreExpr -> DsM CoreExpr)
    forall a. a -> Maybe a
    Just (\CoreExpr
    x -> do CoreExpr
    wrapped <- CoreExpr -> DsM CoreExpr
    ticks CoreExpr
    x
                         CoreExpr -> DsM CoreExpr
    forall (m :: * -> *) a. Monad m => a -> m a
    return (Tickish Id -> CoreExpr -> CoreExpr
    forall b. Tickish Id -> Expr b -> Expr b
    Tick Tickish Id
    Tickish (IdP (GhcPass 'Typechecked))
    tickish CoreExpr
    wrapped))
       -- This encodes that the result is constant True for Hpc tick purposes;
       -- which is specifically what isTrueLHsExpr is trying to find out.
    isTrueLHsExpr (L SrcSpan
    _ (HsBinTick XBinTick (GhcPass 'Typechecked)
    _ ConTag
    ixT ConTag
    _ LHsExpr (GhcPass 'Typechecked)
    e))
        | Just CoreExpr -> DsM CoreExpr
    ticks <- LHsExpr (GhcPass 'Typechecked) -> Maybe (CoreExpr -> DsM CoreExpr)
    isTrueLHsExpr LHsExpr (GhcPass 'Typechecked)
    e
        = (CoreExpr -> DsM CoreExpr) -> Maybe (CoreExpr -> DsM CoreExpr)
    forall a. a -> Maybe a
    Just (\CoreExpr
    x -> do CoreExpr
    e <- CoreExpr -> DsM CoreExpr
    ticks CoreExpr
    x
                         Module
    this_mod <- IOEnv (Env DsGblEnv DsLclEnv) Module
    forall (m :: * -> *). HasModule m => m Module
    getModule
                         CoreExpr -> DsM CoreExpr
    forall (m :: * -> *) a. Monad m => a -> m a
    return (Tickish Id -> CoreExpr -> CoreExpr
    forall b. Tickish Id -> Expr b -> Expr b
    Tick (Module -> ConTag -> Tickish Id
    forall id. Module -> ConTag -> Tickish id
    HpcTick Module
    this_mod ConTag
    ixT) CoreExpr
    e))

    isTrueLHsExpr (L SrcSpan
    _ (HsPar XPar (GhcPass 'Typechecked)
    _ LHsExpr (GhcPass 'Typechecked)
    e))   = LHsExpr (GhcPass 'Typechecked) -> Maybe (CoreExpr -> DsM CoreExpr)
    isTrueLHsExpr LHsExpr (GhcPass 'Typechecked)
    e
    isTrueLHsExpr LHsExpr (GhcPass 'Typechecked)
    _                   = Maybe (CoreExpr -> DsM CoreExpr)
    forall a. Maybe a
    Nothing