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

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

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

    -}

    -- | Typechecking pattern synonym declarations
    module GHC.Tc.TyCl.PatSyn
       ( tcPatSynDecl
       , tcPatSynBuilderBind
       , patSynBuilderOcc
       )
    where

    import GHC.Prelude

    import GHC.Hs
    import GHC.Tc.Gen.Pat
    import GHC.Core.Multiplicity
    import GHC.Core.Type ( tidyTyCoVarBinders, tidyTypes, tidyType )
    import GHC.Core.TyCo.Subst( extendTvSubstWithClone )
    import GHC.Tc.Utils.Monad
    import GHC.Tc.Gen.Sig ( TcPragEnv, emptyPragEnv, completeSigFromId, lookupPragEnv, addInlinePrags )
    import GHC.Tc.Utils.Env
    import GHC.Tc.Utils.TcMType
    import GHC.Tc.Utils.Zonk
    import GHC.Builtin.Types.Prim
    import GHC.Types.Name
    import GHC.Types.Name.Set
    import GHC.Types.SrcLoc
    import GHC.Core.PatSyn
    import GHC.Utils.Panic
    import GHC.Utils.Outputable
    import GHC.Data.FastString
    import GHC.Types.Var
    import GHC.Types.Var.Env( emptyTidyEnv, mkInScopeSet )
    import GHC.Types.Id
    import GHC.Types.Id.Info( RecSelParent(..), setLevityInfoWithType )
    import GHC.Tc.Gen.Bind
    import GHC.Types.Basic
    import GHC.Tc.Solver
    import GHC.Tc.Utils.Unify
    import GHC.Core.Predicate
    import GHC.Builtin.Types
    import GHC.Tc.Utils.TcType
    import GHC.Tc.Types.Evidence
    import GHC.Tc.Types.Origin
    import GHC.Tc.TyCl.Build
    import GHC.Types.Var.Set
    import GHC.Types.Id.Make
    import GHC.Tc.TyCl.Utils
    import GHC.Core.ConLike
    import GHC.Types.FieldLabel
    import GHC.Rename.Env
    import GHC.Data.Bag
    import GHC.Utils.Misc
    import GHC.Driver.Session ( getDynFlags, xopt_FieldSelectors )
    import Data.Maybe( mapMaybe )
    import Control.Monad ( zipWithM )
    import Data.List( partition, mapAccumL )

    #include "HsVersions.h"

    {-
    ************************************************************************
    *                                                                      *
                        Type checking a pattern synonym
    *                                                                      *
    ************************************************************************
    -}

    tcPatSynDecl :: PatSynBind GhcRn GhcRn
                 -> Maybe TcSigInfo
                 -> TcPragEnv -- See Note [Pragmas for pattern synonyms]
                 -> TcM (LHsBinds GhcTc, TcGblEnv)
    tcPatSynDecl :: PatSynBind GhcRn GhcRn
    -> Maybe TcSigInfo -> TcPragEnv -> TcM (LHsBinds GhcTc, TcGblEnv)
    tcPatSynDecl PatSynBind GhcRn GhcRn
    psb Maybe TcSigInfo
    mb_sig TcPragEnv
    prag_fn
      = TcM (LHsBinds GhcTc, TcGblEnv)
    -> TcM (LHsBinds GhcTc, TcGblEnv) -> TcM (LHsBinds GhcTc, TcGblEnv)
    forall r. TcRn r -> TcRn r -> TcRn r
    recoverM (PatSynBind GhcRn GhcRn -> TcM (LHsBinds GhcTc, TcGblEnv)
    recoverPSB PatSynBind GhcRn GhcRn
    psb) (TcM (LHsBinds GhcTc, TcGblEnv) -> TcM (LHsBinds GhcTc, TcGblEnv))
    -> TcM (LHsBinds GhcTc, TcGblEnv) -> TcM (LHsBinds GhcTc, TcGblEnv)
    forall a b. (a -> b) -> a -> b
    $
        case Maybe TcSigInfo
    mb_sig of
          Maybe TcSigInfo
    Nothing                 -> PatSynBind GhcRn GhcRn
    -> TcPragEnv -> TcM (LHsBinds GhcTc, TcGblEnv)
    tcInferPatSynDecl PatSynBind GhcRn GhcRn
    psb TcPragEnv
    prag_fn
          Just (TcPatSynSig TcPatSynInfo
    tpsi) -> PatSynBind GhcRn GhcRn
    -> TcPatSynInfo -> TcPragEnv -> TcM (LHsBinds GhcTc, TcGblEnv)
    tcCheckPatSynDecl PatSynBind GhcRn GhcRn
    psb TcPatSynInfo
    tpsi TcPragEnv
    prag_fn
          Maybe TcSigInfo
    _                       -> String
    -> TcRn
         (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)), TcGblEnv)
    forall a. String -> a
    panic String
    "tcPatSynDecl"

    recoverPSB :: PatSynBind GhcRn GhcRn
               -> TcM (LHsBinds GhcTc, TcGblEnv)
    -- See Note [Pattern synonym error recovery]
    recoverPSB :: PatSynBind GhcRn GhcRn -> TcM (LHsBinds GhcTc, TcGblEnv)
    recoverPSB (PSB { psb_id :: forall idL idR. PatSynBind idL idR -> LIdP idL
    psb_id = L SrcSpanAnnN
    _ Name
    name
                    , psb_args :: forall idL idR. PatSynBind idL idR -> HsPatSynDetails idR
    psb_args = HsPatSynDetails GhcRn
    details })
     = do { Name
    matcher_name <- Name -> (OccName -> OccName) -> TcRnIf TcGblEnv TcLclEnv Name
    forall m n. Name -> (OccName -> OccName) -> TcRnIf m n Name
    newImplicitBinder Name
    name OccName -> OccName
    mkMatcherOcc
          ; let placeholder :: TyThing
    placeholder = ConLike -> TyThing
    AConLike (ConLike -> TyThing) -> ConLike -> TyThing
    forall a b. (a -> b) -> a -> b
    $ PatSyn -> ConLike
    PatSynCon (PatSyn -> ConLike) -> PatSyn -> ConLike
    forall a b. (a -> b) -> a -> b
    $
                              Name -> PatSyn
    mk_placeholder Name
    matcher_name
          ; TcGblEnv
    gbl_env <- [TyThing] -> TcM TcGblEnv -> TcM TcGblEnv
    forall r. [TyThing] -> TcM r -> TcM r
    tcExtendGlobalEnv [TyThing
    placeholder] TcM TcGblEnv
    forall gbl lcl. TcRnIf gbl lcl gbl
    getGblEnv
          ; (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)), TcGblEnv)
    -> TcRn
         (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)), TcGblEnv)
    forall (m :: * -> *) a. Monad m => a -> m a
    return (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
    forall a. Bag a
    emptyBag, TcGblEnv
    gbl_env) }
      where
        ([Name]
    _arg_names, Bool
    is_infix) = HsPatSynDetails GhcRn -> ([Name], Bool)
    collectPatSynArgInfo HsPatSynDetails GhcRn
    details
        mk_placeholder :: Name -> PatSyn
    mk_placeholder Name
    matcher_name
          = Name
    -> Bool
    -> ([VarBndr Id Specificity], [Kind])
    -> ([VarBndr Id Specificity], [Kind])
    -> [Kind]
    -> Kind
    -> PatSynMatcher
    -> PatSynBuilder
    -> [FieldLabel]
    -> PatSyn
    mkPatSyn Name
    name Bool
    is_infix
                            ([Specificity -> Id -> VarBndr Id Specificity
    forall vis. vis -> Id -> VarBndr Id vis
    mkTyVarBinder Specificity
    SpecifiedSpec Id
    alphaTyVar], []) ([], [])
                            [] -- Arg tys
                            Kind
    alphaTy
                            (Name
    matcher_name, Kind
    matcher_ty, Bool
    True) PatSynBuilder
    forall a. Maybe a
    Nothing
                            []  -- Field labels
           where
             -- The matcher_id is used only by the desugarer, so actually
             -- and error-thunk would probably do just as well here.
             matcher_ty :: Kind
    matcher_ty = [Id] -> Kind -> Kind
    mkSpecForAllTys [Id
    alphaTyVar] Kind
    alphaTy

    {- Note [Pattern synonym error recovery]
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    If type inference for a pattern synonym fails, we can't continue with
    the rest of tc_patsyn_finish, because we may get knock-on errors, or
    even a crash.  E.g. from
       pattern What = True :: Maybe
    we get a kind error; and we must stop right away (#15289).

    We stop if there are /any/ unsolved constraints, not just insoluble
    ones; because pattern synonyms are top-level things, we will never
    solve them later if we can't solve them now.  And if we were to carry
    on, tc_patsyn_finish does zonkTcTypeToType, which defaults any
    unsolved unificatdion variables to Any, which confuses the error
    reporting no end (#15685).

    So we use simplifyTop to completely solve the constraint, report
    any errors, throw an exception.

    Even in the event of such an error we can recover and carry on, just
    as we do for value bindings, provided we plug in placeholder for the
    pattern synonym: see recoverPSB.  The goal of the placeholder is not
    to cause a raft of follow-on errors.  I've used the simplest thing for
    now, but we might need to elaborate it a bit later.  (e.g.  I've given
    it zero args, which may cause knock-on errors if it is used in a
    pattern.) But it'll do for now.

    -}

    tcInferPatSynDecl :: PatSynBind GhcRn GhcRn
                      -> TcPragEnv
                      -> TcM (LHsBinds GhcTc, TcGblEnv)
    tcInferPatSynDecl :: PatSynBind GhcRn GhcRn
    -> TcPragEnv -> TcM (LHsBinds GhcTc, TcGblEnv)
    tcInferPatSynDecl (PSB { psb_id :: forall idL idR. PatSynBind idL idR -> LIdP idL
    psb_id = lname :: LIdP GhcRn
    lname@(L SrcSpanAnnN
    _ Name
    name), psb_args :: forall idL idR. PatSynBind idL idR -> HsPatSynDetails idR
    psb_args = HsPatSynDetails GhcRn
    details
                           , psb_def :: forall idL idR. PatSynBind idL idR -> LPat idR
    psb_def = LPat GhcRn
    lpat, psb_dir :: forall idL idR. PatSynBind idL idR -> HsPatSynDir idR
    psb_dir = HsPatSynDir GhcRn
    dir })
                      TcPragEnv
    prag_fn
      = LocatedN Name
    -> TcM (LHsBinds GhcTc, TcGblEnv) -> TcM (LHsBinds GhcTc, TcGblEnv)
    forall a. LocatedN Name -> TcM a -> TcM a
    addPatSynCtxt LocatedN Name
    LIdP GhcRn
    lname (TcM (LHsBinds GhcTc, TcGblEnv) -> TcM (LHsBinds GhcTc, TcGblEnv))
    -> TcM (LHsBinds GhcTc, TcGblEnv) -> TcM (LHsBinds GhcTc, TcGblEnv)
    forall a b. (a -> b) -> a -> b
    $
        do { String -> SDoc -> TcRn ()
    traceTc String
    "tcInferPatSynDecl {" (SDoc -> TcRn ()) -> SDoc -> TcRn ()
    forall a b. (a -> b) -> a -> b
    $ Name -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr Name
    name

           ; let ([Name]
    arg_names, Bool
    is_infix) = HsPatSynDetails GhcRn -> ([Name], Bool)
    collectPatSynArgInfo HsPatSynDetails GhcRn
    details
           ; (TcLevel
    tclvl, WantedConstraints
    wanted, ((GenLocated SrcSpanAnnA (Pat GhcTc)
    lpat', [Id]
    args), Kind
    pat_ty))
                <- TcM ((GenLocated SrcSpanAnnA (Pat GhcTc), [Id]), Kind)
    -> TcM
         (TcLevel, WantedConstraints,
          ((GenLocated SrcSpanAnnA (Pat GhcTc), [Id]), Kind))
    forall a. TcM a -> TcM (TcLevel, WantedConstraints, a)
    pushLevelAndCaptureConstraints  (TcM ((GenLocated SrcSpanAnnA (Pat GhcTc), [Id]), Kind)
     -> TcM
          (TcLevel, WantedConstraints,
           ((GenLocated SrcSpanAnnA (Pat GhcTc), [Id]), Kind)))
    -> TcM ((GenLocated SrcSpanAnnA (Pat GhcTc), [Id]), Kind)
    -> TcM
         (TcLevel, WantedConstraints,
          ((GenLocated SrcSpanAnnA (Pat GhcTc), [Id]), Kind))
    forall a b. (a -> b) -> a -> b
    $
                   HsMatchContext GhcRn
    -> LPat GhcRn -> TcM [Id] -> TcM ((LPat GhcTc, [Id]), Kind)
    forall a.
    HsMatchContext GhcRn
    -> LPat GhcRn -> TcM a -> TcM ((LPat GhcTc, a), Kind)
    tcInferPat HsMatchContext GhcRn
    forall p. HsMatchContext p
    PatSyn LPat GhcRn
    lpat          (TcM [Id] -> TcM ((LPat GhcTc, [Id]), Kind))
    -> TcM [Id] -> TcM ((LPat GhcTc, [Id]), Kind)
    forall a b. (a -> b) -> a -> b
    $
                   (Name -> IOEnv (Env TcGblEnv TcLclEnv) Id) -> [Name] -> TcM [Id]
    forall (t :: * -> *) (m :: * -> *) a b.
    (Traversable t, Monad m) =>
    (a -> m b) -> t a -> m (t b)
    mapM Name -> IOEnv (Env TcGblEnv TcLclEnv) Id
    tcLookupId [Name]
    arg_names

           ; let ([Id]
    ex_tvs, [Id]
    prov_dicts) = LPat GhcTc -> ([Id], [Id])
    tcCollectEx GenLocated SrcSpanAnnA (Pat GhcTc)
    LPat GhcTc
    lpat'

                 named_taus :: [(Name, Kind)]
    named_taus = (Name
    name, Kind
    pat_ty) (Name, Kind) -> [(Name, Kind)] -> [(Name, Kind)]
    forall a. a -> [a] -> [a]
    : (Id -> (Name, Kind)) -> [Id] -> [(Name, Kind)]
    forall a b. (a -> b) -> [a] -> [b]
    map Id -> (Name, Kind)
    mk_named_tau [Id]
    args
                 mk_named_tau :: Id -> (Name, Kind)
    mk_named_tau Id
    arg
                   = (Id -> Name
    forall a. NamedThing a => a -> Name
    getName Id
    arg, [Id] -> Kind -> Kind
    mkSpecForAllTys [Id]
    ex_tvs (Id -> Kind
    varType Id
    arg))
                   -- The mkSpecForAllTys is important (#14552), albeit
                   -- slightly artificial (there is no variable with this funny type).
                   -- We do not want to quantify over variable (alpha::k)
                   -- that mention the existentially-bound type variables
                   -- ex_tvs in its kind k.
                   -- See Note [Type variables whose kind is captured]

           ; (([Id]
    univ_tvs, [Id]
    req_dicts, TcEvBinds
    ev_binds, Bool
    _), WantedConstraints
    residual)
                   <- TcM ([Id], [Id], TcEvBinds, Bool)
    -> TcM (([Id], [Id], TcEvBinds, Bool), WantedConstraints)
    forall a. TcM a -> TcM (a, WantedConstraints)
    captureConstraints (TcM ([Id], [Id], TcEvBinds, Bool)
     -> TcM (([Id], [Id], TcEvBinds, Bool), WantedConstraints))
    -> TcM ([Id], [Id], TcEvBinds, Bool)
    -> TcM (([Id], [Id], TcEvBinds, Bool), WantedConstraints)
    forall a b. (a -> b) -> a -> b
    $
                      TcLevel
    -> InferMode
    -> [TcIdSigInst]
    -> [(Name, Kind)]
    -> WantedConstraints
    -> TcM ([Id], [Id], TcEvBinds, Bool)
    simplifyInfer TcLevel
    tclvl InferMode
    NoRestrictions [] [(Name, Kind)]
    named_taus WantedConstraints
    wanted
           ; Bag EvBind
    top_ev_binds <- TcM (Bag EvBind) -> TcM (Bag EvBind)
    forall r. TcM r -> TcM r
    checkNoErrs (WantedConstraints -> TcM (Bag EvBind)
    simplifyTop WantedConstraints
    residual)
           ; Bag EvBind
    -> TcRn
         (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)), TcGblEnv)
    -> TcRn
         (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)), TcGblEnv)
    forall a. Bag EvBind -> TcM a -> TcM a
    addTopEvBinds Bag EvBind
    top_ev_binds (TcRn
       (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)), TcGblEnv)
     -> TcRn
          (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)), TcGblEnv))
    -> TcRn
         (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)), TcGblEnv)
    -> TcRn
         (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)), TcGblEnv)
    forall a b. (a -> b) -> a -> b
    $

        do { [Id]
    prov_dicts <- (Id -> IOEnv (Env TcGblEnv TcLclEnv) Id) -> [Id] -> TcM [Id]
    forall (t :: * -> *) (m :: * -> *) a b.
    (Traversable t, Monad m) =>
    (a -> m b) -> t a -> m (t b)
    mapM Id -> IOEnv (Env TcGblEnv TcLclEnv) Id
    zonkId [Id]
    prov_dicts
           ; let filtered_prov_dicts :: [Id]
    filtered_prov_dicts = (Id -> Kind) -> [Id] -> [Id]
    forall a. (a -> Kind) -> [a] -> [a]
    mkMinimalBySCs Id -> Kind
    evVarPred [Id]
    prov_dicts
                 -- Filtering: see Note [Remove redundant provided dicts]
                 ([Kind]
    prov_theta, [EvTerm]
    prov_evs)
                     = [(Kind, EvTerm)] -> ([Kind], [EvTerm])
    forall a b. [(a, b)] -> ([a], [b])
    unzip ((Id -> Maybe (Kind, EvTerm)) -> [Id] -> [(Kind, EvTerm)]
    forall a b. (a -> Maybe b) -> [a] -> [b]
    mapMaybe Id -> Maybe (Kind, EvTerm)
    mkProvEvidence [Id]
    filtered_prov_dicts)
                 req_theta :: [Kind]
    req_theta = (Id -> Kind) -> [Id] -> [Kind]
    forall a b. (a -> b) -> [a] -> [b]
    map Id -> Kind
    evVarPred [Id]
    req_dicts

           -- Report coercions that escape
           -- See Note [Coercions that escape]
           ; [Id]
    args <- (Id -> IOEnv (Env TcGblEnv TcLclEnv) Id) -> [Id] -> TcM [Id]
    forall (t :: * -> *) (m :: * -> *) a b.
    (Traversable t, Monad m) =>
    (a -> m b) -> t a -> m (t b)
    mapM Id -> IOEnv (Env TcGblEnv TcLclEnv) Id
    zonkId [Id]
    args
           ; let bad_args :: [(Id, DVarSet)]
    bad_args = [ (Id
    arg, DVarSet
    bad_cos) | Id
    arg <- [Id]
    args [Id] -> [Id] -> [Id]
    forall a. [a] -> [a] -> [a]
    ++ [Id]
    prov_dicts
                                  , let bad_cos :: DVarSet
    bad_cos = (Id -> Bool) -> DVarSet -> DVarSet
    filterDVarSet Id -> Bool
    isId (DVarSet -> DVarSet) -> DVarSet -> DVarSet
    forall a b. (a -> b) -> a -> b
    $
                                                  (Kind -> DVarSet
    tyCoVarsOfTypeDSet (Id -> Kind
    idType Id
    arg))
                                  , Bool -> Bool
    not (DVarSet -> Bool
    isEmptyDVarSet DVarSet
    bad_cos) ]
           ; ((Id, DVarSet) -> TcRn ()) -> [(Id, DVarSet)] -> TcRn ()
    forall (t :: * -> *) (m :: * -> *) a b.
    (Foldable t, Monad m) =>
    (a -> m b) -> t a -> m ()
    mapM_ (Id, DVarSet) -> TcRn ()
    dependentArgErr [(Id, DVarSet)]
    bad_args

           ; String -> SDoc -> TcRn ()
    traceTc String
    "tcInferPatSynDecl }" (SDoc -> TcRn ()) -> SDoc -> TcRn ()
    forall a b. (a -> b) -> a -> b
    $ (Name -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr Name
    name SDoc -> SDoc -> SDoc
    $$ [Id] -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr [Id]
    ex_tvs)
           ; [FieldLabel]
    rec_fields <- Name -> RnM [FieldLabel]
    lookupConstructorFields Name
    name
           ; LocatedN Name
    -> HsPatSynDir GhcRn
    -> Bool
    -> LPat GhcTc
    -> TcPragEnv
    -> ([VarBndr Id Specificity], [Kind], TcEvBinds, [Id])
    -> ([VarBndr Id Specificity], [Kind], [Kind], [EvTerm])
    -> ([LHsExpr GhcTc], [Kind])
    -> Kind
    -> [FieldLabel]
    -> TcM (LHsBinds GhcTc, TcGblEnv)
    tc_patsyn_finish LocatedN Name
    LIdP GhcRn
    lname HsPatSynDir GhcRn
    dir Bool
    is_infix GenLocated SrcSpanAnnA (Pat GhcTc)
    LPat GhcTc
    lpat' TcPragEnv
    prag_fn
                              (Specificity -> [Id] -> [VarBndr Id Specificity]
    forall vis. vis -> [Id] -> [VarBndr Id vis]
    mkTyVarBinders Specificity
    InferredSpec [Id]
    univ_tvs
                                , [Kind]
    req_theta,  TcEvBinds
    ev_binds, [Id]
    req_dicts)
                              (Specificity -> [Id] -> [VarBndr Id Specificity]
    forall vis. vis -> [Id] -> [VarBndr Id vis]
    mkTyVarBinders Specificity
    InferredSpec [Id]
    ex_tvs
                                , [Id] -> [Kind]
    mkTyVarTys [Id]
    ex_tvs, [Kind]
    prov_theta, [EvTerm]
    prov_evs)
                              ((Id -> LocatedA (HsExpr GhcTc))
    -> [Id] -> [LocatedA (HsExpr GhcTc)]
    forall a b. (a -> b) -> [a] -> [b]
    map Id -> LocatedA (HsExpr GhcTc)
    forall (p :: Pass) a.
    IsSrcSpanAnn p a =>
    IdP (GhcPass p) -> LHsExpr (GhcPass p)
    nlHsVar [Id]
    args, (Id -> Kind) -> [Id] -> [Kind]
    forall a b. (a -> b) -> [a] -> [b]
    map Id -> Kind
    idType [Id]
    args)
                              Kind
    pat_ty [FieldLabel]
    rec_fields } }

    mkProvEvidence :: EvId -> Maybe (PredType, EvTerm)
    -- See Note [Equality evidence in pattern synonyms]
    mkProvEvidence :: Id -> Maybe (Kind, EvTerm)
    mkProvEvidence Id
    ev_id
      | EqPred EqRel
    r Kind
    ty1 Kind
    ty2 <- Kind -> Pred
    classifyPredType Kind
    pred
      , let k1 :: Kind
    k1 = HasDebugCallStack => Kind -> Kind
    Kind -> Kind
    tcTypeKind Kind
    ty1
            k2 :: Kind
    k2 = HasDebugCallStack => Kind -> Kind
    Kind -> Kind
    tcTypeKind Kind
    ty2
            is_homo :: Bool
    is_homo = Kind
    k1 HasDebugCallStack => Kind -> Kind -> Bool
    Kind -> Kind -> Bool
    `tcEqType` Kind
    k2
            homo_tys :: [Kind]
    homo_tys   = [Kind
    k1, Kind
    ty1, Kind
    ty2]
            hetero_tys :: [Kind]
    hetero_tys = [Kind
    k1, Kind
    k2, Kind
    ty1, Kind
    ty2]
      = case EqRel
    r of
          EqRel
    ReprEq | Bool
    is_homo
                 -> (Kind, EvTerm) -> Maybe (Kind, EvTerm)
    forall a. a -> Maybe a
    Just ( Class -> [Kind] -> Kind
    mkClassPred Class
    coercibleClass    [Kind]
    homo_tys
                         , DataCon -> [Kind] -> [EvExpr] -> EvTerm
    evDataConApp DataCon
    coercibleDataCon [Kind]
    homo_tys [EvExpr]
    eq_con_args )
                 | Bool
    otherwise -> Maybe (Kind, EvTerm)
    forall a. Maybe a
    Nothing
          EqRel
    NomEq  | Bool
    is_homo
                 -> (Kind, EvTerm) -> Maybe (Kind, EvTerm)
    forall a. a -> Maybe a
    Just ( Class -> [Kind] -> Kind
    mkClassPred Class
    eqClass    [Kind]
    homo_tys
                         , DataCon -> [Kind] -> [EvExpr] -> EvTerm
    evDataConApp DataCon
    eqDataCon [Kind]
    homo_tys [EvExpr]
    eq_con_args )
                 | Bool
    otherwise
                 -> (Kind, EvTerm) -> Maybe (Kind, EvTerm)
    forall a. a -> Maybe a
    Just ( Class -> [Kind] -> Kind
    mkClassPred Class
    heqClass    [Kind]
    hetero_tys
                         , DataCon -> [Kind] -> [EvExpr] -> EvTerm
    evDataConApp DataCon
    heqDataCon [Kind]
    hetero_tys [EvExpr]
    eq_con_args )

      | Bool
    otherwise
      = (Kind, EvTerm) -> Maybe (Kind, EvTerm)
    forall a. a -> Maybe a
    Just (Kind
    pred, EvExpr -> EvTerm
    EvExpr (Id -> EvExpr
    evId Id
    ev_id))
      where
        pred :: Kind
    pred = Id -> Kind
    evVarPred Id
    ev_id
        eq_con_args :: [EvExpr]
    eq_con_args = [Id -> EvExpr
    evId Id
    ev_id]

    dependentArgErr :: (Id, DTyCoVarSet) -> TcM ()
    -- See Note [Coercions that escape]
    dependentArgErr :: (Id, DVarSet) -> TcRn ()
    dependentArgErr (Id
    arg, DVarSet
    bad_cos)
      = SDoc -> TcRn ()
    forall a. SDoc -> TcM a
    failWithTc (SDoc -> TcRn ()) -> SDoc -> TcRn ()
    forall a b. (a -> b) -> a -> b
    $  -- fail here: otherwise we get downstream errors
        [SDoc] -> SDoc
    vcat [ String -> SDoc
    text String
    "Iceland Jack!  Iceland Jack! Stop torturing me!"
             , SDoc -> Int -> SDoc -> SDoc
    hang (String -> SDoc
    text String
    "Pattern-bound variable")
                  Int
    2 (Id -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr Id
    arg SDoc -> SDoc -> SDoc
    <+> SDoc
    dcolon SDoc -> SDoc -> SDoc
    <+> Kind -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr (Id -> Kind
    idType Id
    arg))
             , Int -> SDoc -> SDoc
    nest Int
    2 (SDoc -> SDoc) -> SDoc -> SDoc
    forall a b. (a -> b) -> a -> b
    $
               SDoc -> Int -> SDoc -> SDoc
    hang (String -> SDoc
    text String
    "has a type that mentions pattern-bound coercion"
                     SDoc -> SDoc -> SDoc
    <> [Id] -> SDoc
    forall a. [a] -> SDoc
    plural [Id]
    bad_co_list SDoc -> SDoc -> SDoc
    <> SDoc
    colon)
                  Int
    2 ((Id -> SDoc) -> [Id] -> SDoc
    forall a. (a -> SDoc) -> [a] -> SDoc
    pprWithCommas Id -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr [Id]
    bad_co_list)
             , String -> SDoc
    text String
    "Hint: use -fprint-explicit-coercions to see the coercions"
             , String -> SDoc
    text String
    "Probable fix: add a pattern signature" ]
      where
        bad_co_list :: [Id]
    bad_co_list = DVarSet -> [Id]
    dVarSetElems DVarSet
    bad_cos

    {- Note [Type variables whose kind is captured]
    ~~-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    Consider
      data AST a = Sym [a]
      class Prj s where { prj :: [a] -> Maybe (s a) }
      pattern P x <= Sym (prj -> Just x)

    Here we get a matcher with this type
      $mP :: forall s a. Prj s => AST a -> (s a -> r) -> r -> r

    No problem.  But note that 's' is not fixed by the type of the
    pattern (AST a), nor is it existentially bound.  It's really only
    fixed by the type of the continuation.

    #14552 showed that this can go wrong if the kind of 's' mentions
    existentially bound variables.  We obviously can't make a type like
      $mP :: forall (s::k->*) a. Prj s => AST a -> (forall k. s a -> r)
                                       -> r -> r
    But neither is 's' itself existentially bound, so the forall (s::k->*)
    can't go in the inner forall either.  (What would the matcher apply
    the continuation to?)

    Solution: do not quantiify over any unification variable whose kind
    mentions the existentials.  We can conveniently do that by making the
    "taus" passed to simplifyInfer look like
       forall ex_tvs. arg_ty

    After that, Note [Naughty quantification candidates] in GHC.Tc.Utils.TcMType takes
    over and errors.

    Note [Remove redundant provided dicts]
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    Recall that
       HRefl :: forall k1 k2 (a1:k1) (a2:k2). (k1 ~ k2, a1 ~ a2)
                                           => a1 :~~: a2
    (NB: technically the (k1~k2) existential dictionary is not necessary,
    but it's there at the moment.)

    Now consider (#14394):
       pattern Foo = HRefl
    in a non-poly-kinded module.  We don't want to get
        pattern Foo :: () => (* ~ *, b ~ a) => a :~~: b
    with that redundant (* ~ *).  We'd like to remove it; hence the call to
    mkMinimalWithSCs.

    Similarly consider
      data S a where { MkS :: Ord a => a -> S a }
      pattern Bam x y <- (MkS (x::a), MkS (y::a)))

    The pattern (Bam x y) binds two (Ord a) dictionaries, but we only
    need one.  Again mkMimimalWithSCs removes the redundant one.

    Note [Equality evidence in pattern synonyms]
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    Consider
      data X a where
         MkX :: Eq a => [a] -> X (Maybe a)
      pattern P x = MkG x

    Then there is a danger that GHC will infer
      P :: forall a.  () =>
           forall b. (a ~# Maybe b, Eq b) => [b] -> X a

    The 'builder' for P, which is called in user-code, will then
    have type
      $bP :: forall a b. (a ~# Maybe b, Eq b) => [b] -> X a

    and that is bad because (a ~# Maybe b) is not a predicate type
    (see Note [Types for coercions, predicates, and evidence] in GHC.Core.TyCo.Rep
    and is not implicitly instantiated.

    So in mkProvEvidence we lift (a ~# b) to (a ~ b).  Tiresome, and
    marginally less efficient, if the builder/martcher are not inlined.

    See also Note [Lift equality constraints when quantifying] in GHC.Tc.Utils.TcType

    Note [Coercions that escape]
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    #14507 showed an example where the inferred type of the matcher
    for the pattern synonym was something like
       $mSO :: forall (r :: TYPE rep) kk (a :: k).
               TypeRep k a
               -> ((Bool ~ k) => TypeRep Bool (a |> co_a2sv) -> r)
               -> (Void# -> r)
               -> r

    What is that co_a2sv :: Bool ~# *??  It was bound (via a superclass
    selection) by the pattern being matched; and indeed it is implicit in
    the context (Bool ~ k).  You could imagine trying to extract it like
    this:
       $mSO :: forall (r :: TYPE rep) kk (a :: k).
               TypeRep k a
               -> ( co :: ((Bool :: *) ~ (k :: *)) =>
                      let co_a2sv = sc_sel co
                      in TypeRep Bool (a |> co_a2sv) -> r)
               -> (Void# -> r)
               -> r

    But we simply don't allow that in types.  Maybe one day but not now.

    How to detect this situation?  We just look for free coercion variables
    in the types of any of the arguments to the matcher.  The error message
    is not very helpful, but at least we don't get a Lint error.
    -}

    tcCheckPatSynDecl :: PatSynBind GhcRn GhcRn
                      -> TcPatSynInfo
                      -> TcPragEnv
                      -> TcM (LHsBinds GhcTc, TcGblEnv)
    tcCheckPatSynDecl :: PatSynBind GhcRn GhcRn
    -> TcPatSynInfo -> TcPragEnv -> TcM (LHsBinds GhcTc, TcGblEnv)
    tcCheckPatSynDecl psb :: PatSynBind GhcRn GhcRn
    psb@PSB{ psb_id :: forall idL idR. PatSynBind idL idR -> LIdP idL
    psb_id = lname :: LIdP GhcRn
    lname@(L SrcSpanAnnN
    _ Name
    name), psb_args :: forall idL idR. PatSynBind idL idR -> HsPatSynDetails idR
    psb_args = HsPatSynDetails GhcRn
    details
                             , psb_def :: forall idL idR. PatSynBind idL idR -> LPat idR
    psb_def = LPat GhcRn
    lpat, psb_dir :: forall idL idR. PatSynBind idL idR -> HsPatSynDir idR
    psb_dir = HsPatSynDir GhcRn
    dir }
                      TPSI{ patsig_implicit_bndrs :: TcPatSynInfo -> [VarBndr Id Specificity]
    patsig_implicit_bndrs = [VarBndr Id Specificity]
    implicit_bndrs
                          , patsig_univ_bndrs :: TcPatSynInfo -> [VarBndr Id Specificity]
    patsig_univ_bndrs = [VarBndr Id Specificity]
    explicit_univ_bndrs, patsig_req :: TcPatSynInfo -> [Kind]
    patsig_req  = [Kind]
    req_theta
                          , patsig_ex_bndrs :: TcPatSynInfo -> [VarBndr Id Specificity]
    patsig_ex_bndrs   = [VarBndr Id Specificity]
    explicit_ex_bndrs,   patsig_prov :: TcPatSynInfo -> [Kind]
    patsig_prov = [Kind]
    prov_theta
                          , patsig_body_ty :: TcPatSynInfo -> Kind
    patsig_body_ty    = Kind
    sig_body_ty }
                      TcPragEnv
    prag_fn
      = LocatedN Name
    -> TcM (LHsBinds GhcTc, TcGblEnv) -> TcM (LHsBinds GhcTc, TcGblEnv)
    forall a. LocatedN Name -> TcM a -> TcM a
    addPatSynCtxt LocatedN Name
    LIdP GhcRn
    lname (TcM (LHsBinds GhcTc, TcGblEnv) -> TcM (LHsBinds GhcTc, TcGblEnv))
    -> TcM (LHsBinds GhcTc, TcGblEnv) -> TcM (LHsBinds GhcTc, TcGblEnv)
    forall a b. (a -> b) -> a -> b
    $
        do { String -> SDoc -> TcRn ()
    traceTc String
    "tcCheckPatSynDecl" (SDoc -> TcRn ()) -> SDoc -> TcRn ()
    forall a b. (a -> b) -> a -> b
    $
             [SDoc] -> SDoc
    vcat [ [VarBndr Id Specificity] -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr [VarBndr Id Specificity]
    implicit_bndrs, [VarBndr Id Specificity] -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr [VarBndr Id Specificity]
    explicit_univ_bndrs, [Kind] -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr [Kind]
    req_theta
                  , [VarBndr Id Specificity] -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr [VarBndr Id Specificity]
    explicit_ex_bndrs, [Kind] -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr [Kind]
    prov_theta, Kind -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr Kind
    sig_body_ty ]

           ; let decl_arity :: Int
    decl_arity = [Name] -> Int
    forall (t :: * -> *) a. Foldable t => t a -> Int
    length [Name]
    arg_names
                 ([Name]
    arg_names, Bool
    is_infix) = HsPatSynDetails GhcRn -> ([Name], Bool)
    collectPatSynArgInfo HsPatSynDetails GhcRn
    details

           ; ([Scaled Kind]
    arg_tys, Kind
    pat_ty) <- case Int -> Kind -> Either Int ([Scaled Kind], Kind)
    tcSplitFunTysN Int
    decl_arity Kind
    sig_body_ty of
                                     Right ([Scaled Kind], Kind)
    stuff  -> ([Scaled Kind], Kind)
    -> IOEnv (Env TcGblEnv TcLclEnv) ([Scaled Kind], Kind)
    forall (m :: * -> *) a. Monad m => a -> m a
    return ([Scaled Kind], Kind)
    stuff
                                     Left Int
    missing -> Name
    -> Int
    -> Int
    -> IOEnv (Env TcGblEnv TcLclEnv) ([Scaled Kind], Kind)
    forall a. Name -> Int -> Int -> TcM a
    wrongNumberOfParmsErr Name
    name Int
    decl_arity Int
    missing

           -- Complain about:  pattern P :: () => forall x. x -> P x
           -- The existential 'x' should not appear in the result type
           -- Can't check this until we know P's arity (decl_arity above)
           ; let bad_tvs :: [Id]
    bad_tvs = (Id -> Bool) -> [Id] -> [Id]
    forall a. (a -> Bool) -> [a] -> [a]
    filter (Id -> VarSet -> Bool
    `elemVarSet` Kind -> VarSet
    tyCoVarsOfType Kind
    pat_ty) ([Id] -> [Id]) -> [Id] -> [Id]
    forall a b. (a -> b) -> a -> b
    $ [VarBndr Id Specificity] -> [Id]
    forall tv argf. [VarBndr tv argf] -> [tv]
    binderVars [VarBndr Id Specificity]
    explicit_ex_bndrs
           ; Bool -> SDoc -> TcRn ()
    checkTc ([Id] -> Bool
    forall (t :: * -> *) a. Foldable t => t a -> Bool
    null [Id]
    bad_tvs) (SDoc -> TcRn ()) -> SDoc -> TcRn ()
    forall a b. (a -> b) -> a -> b
    $
             SDoc -> Int -> SDoc -> SDoc
    hang ([SDoc] -> SDoc
    sep [ String -> SDoc
    text String
    "The result type of the signature for" SDoc -> SDoc -> SDoc
    <+> SDoc -> SDoc
    quotes (Name -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr Name
    name) SDoc -> SDoc -> SDoc
    <> SDoc
    comma
                       , String -> SDoc
    text String
    "namely" SDoc -> SDoc -> SDoc
    <+> SDoc -> SDoc
    quotes (Kind -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr Kind
    pat_ty) ])
                Int
    2 (String -> SDoc
    text String
    "mentions existential type variable" SDoc -> SDoc -> SDoc
    <> [Id] -> SDoc
    forall a. [a] -> SDoc
    plural [Id]
    bad_tvs
                   SDoc -> SDoc -> SDoc
    <+> [Id] -> SDoc
    forall a. Outputable a => [a] -> SDoc
    pprQuotedList [Id]
    bad_tvs)

             -- See Note [The pattern-synonym signature splitting rule] in GHC.Tc.Gen.Sig
           ; let univ_fvs :: VarSet
    univ_fvs = VarSet -> VarSet
    closeOverKinds (VarSet -> VarSet) -> VarSet -> VarSet
    forall a b. (a -> b) -> a -> b
    $
                            ([Kind] -> VarSet
    tyCoVarsOfTypes (Kind
    pat_ty Kind -> [Kind] -> [Kind]
    forall a. a -> [a] -> [a]
    : [Kind]
    req_theta) VarSet -> [Id] -> VarSet
    `extendVarSetList` ([VarBndr Id Specificity] -> [Id]
    forall tv argf. [VarBndr tv argf] -> [tv]
    binderVars [VarBndr Id Specificity]
    explicit_univ_bndrs))
                 ([VarBndr Id Specificity]
    extra_univ, [VarBndr Id Specificity]
    extra_ex) = (VarBndr Id Specificity -> Bool)
    -> [VarBndr Id Specificity]
    -> ([VarBndr Id Specificity], [VarBndr Id Specificity])
    forall a. (a -> Bool) -> [a] -> ([a], [a])
    partition ((Id -> VarSet -> Bool
    `elemVarSet` VarSet
    univ_fvs) (Id -> Bool)
    -> (VarBndr Id Specificity -> Id) -> VarBndr Id Specificity -> Bool
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . VarBndr Id Specificity -> Id
    forall tv argf. VarBndr tv argf -> tv
    binderVar) [VarBndr Id Specificity]
    implicit_bndrs
                 univ_bndrs :: [VarBndr Id Specificity]
    univ_bndrs = [VarBndr Id Specificity]
    extra_univ [VarBndr Id Specificity]
    -> [VarBndr Id Specificity] -> [VarBndr Id Specificity]
    forall a. [a] -> [a] -> [a]
    ++ [VarBndr Id Specificity]
    explicit_univ_bndrs
                 ex_bndrs :: [VarBndr Id Specificity]
    ex_bndrs   = [VarBndr Id Specificity]
    extra_ex   [VarBndr Id Specificity]
    -> [VarBndr Id Specificity] -> [VarBndr Id Specificity]
    forall a. [a] -> [a] -> [a]
    ++ [VarBndr Id Specificity]
    explicit_ex_bndrs
                 univ_tvs :: [Id]
    univ_tvs   = [VarBndr Id Specificity] -> [Id]
    forall tv argf. [VarBndr tv argf] -> [tv]
    binderVars [VarBndr Id Specificity]
    univ_bndrs
                 ex_tvs :: [Id]
    ex_tvs     = [VarBndr Id Specificity] -> [Id]
    forall tv argf. [VarBndr tv argf] -> [tv]
    binderVars [VarBndr Id Specificity]
    ex_bndrs

             -- Skolemise the quantified type variables. This is necessary
             -- in order to check the actual pattern type against the
             -- expected type. Even though the tyvars in the type are
             -- already skolems, this step changes their TcLevels,
             -- avoiding level-check errors when unifying.
           ; (TCvSubst
    skol_subst0, [VarBndr Id Specificity]
    skol_univ_bndrs) <- TCvSubst
    -> [VarBndr Id Specificity]
    -> TcM (TCvSubst, [VarBndr Id Specificity])
    forall flag.
    TCvSubst -> [VarBndr Id flag] -> TcM (TCvSubst, [VarBndr Id flag])
    skolemiseTvBndrsX TCvSubst
    emptyTCvSubst [VarBndr Id Specificity]
    univ_bndrs
           ; (TCvSubst
    skol_subst, [VarBndr Id Specificity]
    skol_ex_bndrs)    <- TCvSubst
    -> [VarBndr Id Specificity]
    -> TcM (TCvSubst, [VarBndr Id Specificity])
    forall flag.
    TCvSubst -> [VarBndr Id flag] -> TcM (TCvSubst, [VarBndr Id flag])
    skolemiseTvBndrsX TCvSubst
    skol_subst0   [VarBndr Id Specificity]
    ex_bndrs
           ; let skol_univ_tvs :: [Id]
    skol_univ_tvs   = [VarBndr Id Specificity] -> [Id]
    forall tv argf. [VarBndr tv argf] -> [tv]
    binderVars [VarBndr Id Specificity]
    skol_univ_bndrs
                 skol_ex_tvs :: [Id]
    skol_ex_tvs     = [VarBndr Id Specificity] -> [Id]
    forall tv argf. [VarBndr tv argf] -> [tv]
    binderVars [VarBndr Id Specificity]
    skol_ex_bndrs
                 skol_req_theta :: [Kind]
    skol_req_theta  = HasCallStack => TCvSubst -> [Kind] -> [Kind]
    TCvSubst -> [Kind] -> [Kind]
    substTheta TCvSubst
    skol_subst0 [Kind]
    req_theta
                 skol_prov_theta :: [Kind]
    skol_prov_theta = HasCallStack => TCvSubst -> [Kind] -> [Kind]
    TCvSubst -> [Kind] -> [Kind]
    substTheta TCvSubst
    skol_subst  [Kind]
    prov_theta
                 skol_arg_tys :: [Kind]
    skol_arg_tys    = HasCallStack => TCvSubst -> [Kind] -> [Kind]
    TCvSubst -> [Kind] -> [Kind]
    substTys   TCvSubst
    skol_subst  ((Scaled Kind -> Kind) -> [Scaled Kind] -> [Kind]
    forall a b. (a -> b) -> [a] -> [b]
    map Scaled Kind -> Kind
    forall a. Scaled a -> a
    scaledThing [Scaled Kind]
    arg_tys)
                 skol_pat_ty :: Kind
    skol_pat_ty     = HasCallStack => TCvSubst -> Kind -> Kind
    TCvSubst -> Kind -> Kind
    substTy    TCvSubst
    skol_subst  Kind
    pat_ty

                 univ_tv_prs :: [(Name, Id)]
    univ_tv_prs     = [ (Id -> Name
    forall a. NamedThing a => a -> Name
    getName Id
    orig_univ_tv, Id
    skol_univ_tv)
                                   | (Id
    orig_univ_tv, Id
    skol_univ_tv) <- [Id]
    univ_tvs [Id] -> [Id] -> [(Id, Id)]
    forall a b. [a] -> [b] -> [(a, b)]
    `zip` [Id]
    skol_univ_tvs ]

           -- Right!  Let's check the pattern against the signature
           -- See Note [Checking against a pattern signature]
           ; [Id]
    req_dicts <- [Kind] -> TcM [Id]
    newEvVars [Kind]
    skol_req_theta
           ; (TcLevel
    tclvl, WantedConstraints
    wanted, (GenLocated SrcSpanAnnA (Pat GhcTc)
    lpat', ([Id]
    ex_tvs', [EvTerm]
    prov_dicts, [LocatedA (HsExpr GhcTc)]
    args'))) <-
               ASSERT2( equalLength arg_names arg_tys, ppr name $$ ppr arg_names $$ ppr arg_tys )
               TcM
      (GenLocated SrcSpanAnnA (Pat GhcTc),
       ([Id], [EvTerm], [LocatedA (HsExpr GhcTc)]))
    -> IOEnv
         (Env TcGblEnv TcLclEnv)
         (TcLevel, WantedConstraints,
          (GenLocated SrcSpanAnnA (Pat GhcTc),
           ([Id], [EvTerm], [LocatedA (HsExpr GhcTc)])))
    forall a. TcM a -> TcM (TcLevel, WantedConstraints, a)
    pushLevelAndCaptureConstraints   (TcM
       (GenLocated SrcSpanAnnA (Pat GhcTc),
        ([Id], [EvTerm], [LocatedA (HsExpr GhcTc)]))
     -> IOEnv
          (Env TcGblEnv TcLclEnv)
          (TcLevel, WantedConstraints,
           (GenLocated SrcSpanAnnA (Pat GhcTc),
            ([Id], [EvTerm], [LocatedA (HsExpr GhcTc)]))))
    -> TcM
         (GenLocated SrcSpanAnnA (Pat GhcTc),
          ([Id], [EvTerm], [LocatedA (HsExpr GhcTc)]))
    -> IOEnv
         (Env TcGblEnv TcLclEnv)
         (TcLevel, WantedConstraints,
          (GenLocated SrcSpanAnnA (Pat GhcTc),
           ([Id], [EvTerm], [LocatedA (HsExpr GhcTc)])))
    forall a b. (a -> b) -> a -> b
    $
               [(Name, Id)]
    -> TcM
         (GenLocated SrcSpanAnnA (Pat GhcTc),
          ([Id], [EvTerm], [LocatedA (HsExpr GhcTc)]))
    -> TcM
         (GenLocated SrcSpanAnnA (Pat GhcTc),
          ([Id], [EvTerm], [LocatedA (HsExpr GhcTc)]))
    forall r. [(Name, Id)] -> TcM r -> TcM r
    tcExtendNameTyVarEnv [(Name, Id)]
    univ_tv_prs (TcM
       (GenLocated SrcSpanAnnA (Pat GhcTc),
        ([Id], [EvTerm], [LocatedA (HsExpr GhcTc)]))
     -> TcM
          (GenLocated SrcSpanAnnA (Pat GhcTc),
           ([Id], [EvTerm], [LocatedA (HsExpr GhcTc)])))
    -> TcM
         (GenLocated SrcSpanAnnA (Pat GhcTc),
          ([Id], [EvTerm], [LocatedA (HsExpr GhcTc)]))
    -> TcM
         (GenLocated SrcSpanAnnA (Pat GhcTc),
          ([Id], [EvTerm], [LocatedA (HsExpr GhcTc)]))
    forall a b. (a -> b) -> a -> b
    $
               HsMatchContext GhcRn
    -> LPat GhcRn
    -> Scaled Kind
    -> TcM ([Id], [EvTerm], [LocatedA (HsExpr GhcTc)])
    -> TcM (LPat GhcTc, ([Id], [EvTerm], [LocatedA (HsExpr GhcTc)]))
    forall a.
    HsMatchContext GhcRn
    -> LPat GhcRn -> Scaled Kind -> TcM a -> TcM (LPat GhcTc, a)
    tcCheckPat HsMatchContext GhcRn
    forall p. HsMatchContext p
    PatSyn LPat GhcRn
    lpat (Kind -> Scaled Kind
    forall a. a -> Scaled a
    unrestricted Kind
    skol_pat_ty)   (TcM ([Id], [EvTerm], [LocatedA (HsExpr GhcTc)])
     -> TcM (LPat GhcTc, ([Id], [EvTerm], [LocatedA (HsExpr GhcTc)])))
    -> TcM ([Id], [EvTerm], [LocatedA (HsExpr GhcTc)])
    -> TcM (LPat GhcTc, ([Id], [EvTerm], [LocatedA (HsExpr GhcTc)]))
    forall a b. (a -> b) -> a -> b
    $
               do { let in_scope :: InScopeSet
    in_scope    = VarSet -> InScopeSet
    mkInScopeSet ([Id] -> VarSet
    mkVarSet [Id]
    skol_univ_tvs)
                        empty_subst :: TCvSubst
    empty_subst = InScopeSet -> TCvSubst
    mkEmptyTCvSubst InScopeSet
    in_scope
                  ; (TCvSubst
    inst_subst, [Id]
    ex_tvs') <- (TCvSubst -> Id -> IOEnv (Env TcGblEnv TcLclEnv) (TCvSubst, Id))
    -> TCvSubst
    -> [Id]
    -> IOEnv (Env TcGblEnv TcLclEnv) (TCvSubst, [Id])
    forall (m :: * -> *) acc x y.
    Monad m =>
    (acc -> x -> m (acc, y)) -> acc -> [x] -> m (acc, [y])
    mapAccumLM TCvSubst -> Id -> IOEnv (Env TcGblEnv TcLclEnv) (TCvSubst, Id)
    newMetaTyVarX TCvSubst
    empty_subst [Id]
    skol_ex_tvs
                        -- newMetaTyVarX: see the "Existential type variables"
                        -- part of Note [Checking against a pattern signature]
                  ; String -> SDoc -> TcRn ()
    traceTc String
    "tcpatsyn1" ([SDoc] -> SDoc
    vcat [ Id -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr Id
    v SDoc -> SDoc -> SDoc
    <+> SDoc
    dcolon SDoc -> SDoc -> SDoc
    <+> Kind -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr (Id -> Kind
    tyVarKind Id
    v) | Id
    v <- [Id]
    ex_tvs])
                  ; String -> SDoc -> TcRn ()
    traceTc String
    "tcpatsyn2" ([SDoc] -> SDoc
    vcat [ Id -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr Id
    v SDoc -> SDoc -> SDoc
    <+> SDoc
    dcolon SDoc -> SDoc -> SDoc
    <+> Kind -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr (Id -> Kind
    tyVarKind Id
    v) | Id
    v <- [Id]
    ex_tvs'])
                  ; let prov_theta' :: [Kind]
    prov_theta' = HasCallStack => TCvSubst -> [Kind] -> [Kind]
    TCvSubst -> [Kind] -> [Kind]
    substTheta TCvSubst
    inst_subst [Kind]
    skol_prov_theta
                      -- Add univ_tvs to the in_scope set to
                      -- satisfy the substitution invariant. There's no need to
                      -- add 'ex_tvs' as they are already in the domain of the
                      -- substitution.
                      -- See also Note [The substitution invariant] in GHC.Core.TyCo.Subst.
                  ; [EvTerm]
    prov_dicts <- (Kind -> IOEnv (Env TcGblEnv TcLclEnv) EvTerm)
    -> [Kind] -> IOEnv (Env TcGblEnv TcLclEnv) [EvTerm]
    forall (t :: * -> *) (m :: * -> *) a b.
    (Traversable t, Monad m) =>
    (a -> m b) -> t a -> m (t b)
    mapM (CtOrigin -> Kind -> IOEnv (Env TcGblEnv TcLclEnv) EvTerm
    emitWanted (PatSynBind GhcRn GhcRn -> CtOrigin
    ProvCtxtOrigin PatSynBind GhcRn GhcRn
    psb)) [Kind]
    prov_theta'
                  ; [LocatedA (HsExpr GhcTc)]
    args'      <- (Name
     -> Kind -> IOEnv (Env TcGblEnv TcLclEnv) (LocatedA (HsExpr GhcTc)))
    -> [Name]
    -> [Kind]
    -> IOEnv (Env TcGblEnv TcLclEnv) [LocatedA (HsExpr GhcTc)]
    forall (m :: * -> *) a b c.
    Applicative m =>
    (a -> b -> m c) -> [a] -> [b] -> m [c]
    zipWithM (TCvSubst -> Name -> Kind -> TcM (LHsExpr GhcTc)
    tc_arg TCvSubst
    inst_subst) [Name]
    arg_names
                                           [Kind]
    skol_arg_tys
                  ; ([Id], [EvTerm], [LocatedA (HsExpr GhcTc)])
    -> TcM ([Id], [EvTerm], [LocatedA (HsExpr GhcTc)])
    forall (m :: * -> *) a. Monad m => a -> m a
    return ([Id]
    ex_tvs', [EvTerm]
    prov_dicts, [LocatedA (HsExpr GhcTc)]
    args') }

           ; let skol_info :: SkolemInfo
    skol_info = UserTypeCtxt -> Kind -> [(Name, Id)] -> SkolemInfo
    SigSkol (Name -> UserTypeCtxt
    PatSynCtxt Name
    name) Kind
    pat_ty []
                             -- The type here is a bit bogus, but we do not print
                             -- the type for PatSynCtxt, so it doesn't matter
                             -- See Note [Skolem info for pattern synonyms] in "GHC.Tc.Types.Origin"
           ; (Bag Implication
    implics, TcEvBinds
    ev_binds) <- TcLevel
    -> SkolemInfo
    -> [Id]
    -> [Id]
    -> WantedConstraints
    -> TcM (Bag Implication, TcEvBinds)
    buildImplicationFor TcLevel
    tclvl SkolemInfo
    skol_info [Id]
    skol_univ_tvs
                                                        [Id]
    req_dicts WantedConstraints
    wanted

           -- Solve the constraints now, because we are about to make a PatSyn,
           -- which should not contain unification variables and the like (#10997)
           ; Bag Implication -> TcRn ()
    simplifyTopImplic Bag Implication
    implics

           -- ToDo: in the bidirectional case, check that the ex_tvs' are all distinct
           -- Otherwise we may get a type error when typechecking the builder,
           -- when that should be impossible

           ; String -> SDoc -> TcRn ()
    traceTc String
    "tcCheckPatSynDecl }" (SDoc -> TcRn ()) -> SDoc -> TcRn ()
    forall a b. (a -> b) -> a -> b
    $ Name -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr Name
    name

           ; [FieldLabel]
    rec_fields <- Name -> RnM [FieldLabel]
    lookupConstructorFields Name
    name
           ; LocatedN Name
    -> HsPatSynDir GhcRn
    -> Bool
    -> LPat GhcTc
    -> TcPragEnv
    -> ([VarBndr Id Specificity], [Kind], TcEvBinds, [Id])
    -> ([VarBndr Id Specificity], [Kind], [Kind], [EvTerm])
    -> ([LHsExpr GhcTc], [Kind])
    -> Kind
    -> [FieldLabel]
    -> TcM (LHsBinds GhcTc, TcGblEnv)
    tc_patsyn_finish LocatedN Name
    LIdP GhcRn
    lname HsPatSynDir GhcRn
    dir Bool
    is_infix GenLocated SrcSpanAnnA (Pat GhcTc)
    LPat GhcTc
    lpat' TcPragEnv
    prag_fn
                              ([VarBndr Id Specificity]
    skol_univ_bndrs, [Kind]
    skol_req_theta, TcEvBinds
    ev_binds, [Id]
    req_dicts)
                              ([VarBndr Id Specificity]
    skol_ex_bndrs, [Id] -> [Kind]
    mkTyVarTys [Id]
    ex_tvs', [Kind]
    skol_prov_theta, [EvTerm]
    prov_dicts)
                              ([LocatedA (HsExpr GhcTc)]
    [LHsExpr GhcTc]
    args', [Kind]
    skol_arg_tys)
                              Kind
    skol_pat_ty [FieldLabel]
    rec_fields }
      where
        tc_arg :: TCvSubst -> Name -> Type -> TcM (LHsExpr GhcTc)
         -- Look up the variable actually bound by lpat
         -- and check that it has the expected type
        tc_arg :: TCvSubst -> Name -> Kind -> TcM (LHsExpr GhcTc)
    tc_arg TCvSubst
    subst Name
    arg_name Kind
    arg_ty
          = SrcSpan -> TcM (LHsExpr GhcTc) -> TcM (LHsExpr GhcTc)
    forall a. SrcSpan -> TcRn a -> TcRn a
    setSrcSpan (Name -> SrcSpan
    nameSrcSpan Name
    arg_name) (TcM (LHsExpr GhcTc) -> TcM (LHsExpr GhcTc))
    -> TcM (LHsExpr GhcTc) -> TcM (LHsExpr GhcTc)
    forall a b. (a -> b) -> a -> b
    $
               -- Set the SrcSpan to be the binding site of the Id (#18856)
               -- e.g.  pattern P :: Int -> Maybe (Int,Bool)
               --       pattern P x = Just (x,True)
               -- Before unifying x's actual type with its expected type, in tc_arg, set
               -- location to x's binding site in lpat, namely the 'x' in Just (x,True).
               -- Else the error message location is wherever tcCheckPat finished,
               -- namely the right-hand corner of the pattern
            do { Id
    arg_id <- Name -> IOEnv (Env TcGblEnv TcLclEnv) Id
    tcLookupId Name
    arg_name
               ; HsWrapper
    wrap <- UserTypeCtxt -> Kind -> Kind -> TcM HsWrapper
    tcSubTypeSigma UserTypeCtxt
    GenSigCtxt
                                        (Id -> Kind
    idType Id
    arg_id)
                                        (HasCallStack => TCvSubst -> Kind -> Kind
    TCvSubst -> Kind -> Kind
    substTy TCvSubst
    subst Kind
    arg_ty)
                    -- Why do we need tcSubType here?
                    -- See Note [Pattern synonyms and higher rank types]
               ; LocatedA (HsExpr GhcTc)
    -> IOEnv (Env TcGblEnv TcLclEnv) (LocatedA (HsExpr GhcTc))
    forall (m :: * -> *) a. Monad m => a -> m a
    return (HsWrapper -> LHsExpr GhcTc -> LHsExpr GhcTc
    mkLHsWrap HsWrapper
    wrap (LHsExpr GhcTc -> LHsExpr GhcTc) -> LHsExpr GhcTc -> LHsExpr GhcTc
    forall a b. (a -> b) -> a -> b
    $ IdP GhcTc -> LHsExpr GhcTc
    forall (p :: Pass) a.
    IsSrcSpanAnn p a =>
    IdP (GhcPass p) -> LHsExpr (GhcPass p)
    nlHsVar Id
    IdP GhcTc
    arg_id) }

    skolemiseTvBndrsX :: TCvSubst -> [VarBndr TyVar flag]
                      -> TcM (TCvSubst, [VarBndr TcTyVar flag])
    -- Make new TcTyVars, all skolems with levels, but do not clone
    -- The level is one level deeper than the current level
    -- See Note [Skolemising when checking a pattern synonym]
    skolemiseTvBndrsX :: forall flag.
    TCvSubst -> [VarBndr Id flag] -> TcM (TCvSubst, [VarBndr Id flag])
    skolemiseTvBndrsX TCvSubst
    orig_subst [VarBndr Id flag]
    tvs
      = do { TcLevel
    tc_lvl <- TcM TcLevel
    getTcLevel
           ; let pushed_lvl :: TcLevel
    pushed_lvl = TcLevel -> TcLevel
    pushTcLevel TcLevel
    tc_lvl
                 details :: TcTyVarDetails
    details    = TcLevel -> Bool -> TcTyVarDetails
    SkolemTv TcLevel
    pushed_lvl Bool
    False

                 mk_skol_tv_x :: TCvSubst -> VarBndr TyVar flag
                              -> (TCvSubst, VarBndr TcTyVar flag)
                 mk_skol_tv_x :: forall flag.
    TCvSubst -> VarBndr Id flag -> (TCvSubst, VarBndr Id flag)
    mk_skol_tv_x TCvSubst
    subst (Bndr Id
    tv flag
    flag)
                   = (TCvSubst
    subst', Id -> flag -> VarBndr Id flag
    forall var argf. var -> argf -> VarBndr var argf
    Bndr Id
    new_tv flag
    flag)
                   where
                     new_kind :: Kind
    new_kind = TCvSubst -> Kind -> Kind
    substTyUnchecked TCvSubst
    subst (Id -> Kind
    tyVarKind Id
    tv)
                     new_tv :: Id
    new_tv   = Name -> Kind -> TcTyVarDetails -> Id
    mkTcTyVar (Id -> Name
    tyVarName Id
    tv) Kind
    new_kind TcTyVarDetails
    details
                     subst' :: TCvSubst
    subst'   = TCvSubst -> Id -> Id -> TCvSubst
    extendTvSubstWithClone TCvSubst
    subst Id
    tv Id
    new_tv

           ; (TCvSubst, [VarBndr Id flag]) -> TcM (TCvSubst, [VarBndr Id flag])
    forall (m :: * -> *) a. Monad m => a -> m a
    return ((TCvSubst -> VarBndr Id flag -> (TCvSubst, VarBndr Id flag))
    -> TCvSubst -> [VarBndr Id flag] -> (TCvSubst, [VarBndr Id flag])
    forall (t :: * -> *) a b c.
    Traversable t =>
    (a -> b -> (a, c)) -> a -> t b -> (a, t c)
    mapAccumL TCvSubst -> VarBndr Id flag -> (TCvSubst, VarBndr Id flag)
    forall flag.
    TCvSubst -> VarBndr Id flag -> (TCvSubst, VarBndr Id flag)
    mk_skol_tv_x TCvSubst
    orig_subst [VarBndr Id flag]
    tvs) }

    {- Note [Skolemising when checking a pattern synonym]
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    Consider
       pattern P1 :: forall a. a -> Maybe a
       pattern P1 x <- Just x where
          P1 x = Just (x :: a)

    The scoped type variable 'a' scopes over the builder RHS, Just (x::a).
    But the builder RHS is typechecked much later in tcPatSynBuilderBind,
    and gets its scoped type variables from the type of the builder_id.
    The easiest way to achieve this is not to clone when skolemising.

    Hence a special-purpose skolemiseTvBndrX here, similar to
    GHC.Tc.Utils.Instantiate.tcInstSkolTyVarsX except that the latter
    does cloning.

    [Pattern synonyms and higher rank types]
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    Consider
      data T = MkT (forall a. a->a)

      pattern P :: (Int -> Int) -> T
      pattern P x <- MkT x

    This should work.  But in the matcher we must match against MkT, and then
    instantiate its argument 'x', to get a function of type (Int -> Int).
    Equality is not enough!  #13752 was an example.

    Note [The pattern-synonym signature splitting rule]
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    Given a pattern signature, we must split
         the kind-generalised variables, and
         the implicitly-bound variables
    into universal and existential.  The rule is this
    (see discussion on #11224):

         The universal tyvars are the ones mentioned in
              - univ_tvs: the user-specified (forall'd) universals
              - req_theta
              - res_ty
         The existential tyvars are all the rest

    For example

       pattern P :: () => b -> T a
       pattern P x = ...

    Here 'a' is universal, and 'b' is existential.  But there is a wrinkle:
    how do we split the arg_tys from req_ty?  Consider

       pattern Q :: () => b -> S c -> T a
       pattern Q x = ...

    This is an odd example because Q has only one syntactic argument, and
    so presumably is defined by a view pattern matching a function.  But
    it can happen (#11977, #12108).

    We don't know Q's arity from the pattern signature, so we have to wait
    until we see the pattern declaration itself before deciding res_ty is,
    and hence which variables are existential and which are universal.

    And that in turn is why TcPatSynInfo has a separate field,
    patsig_implicit_bndrs, to capture the implicitly bound type variables,
    because we don't yet know how to split them up.

    It's a slight compromise, because it means we don't really know the
    pattern synonym's real signature until we see its declaration.  So,
    for example, in hs-boot file, we may need to think what to do...
    (eg don't have any implicitly-bound variables).

    Note [Checking against a pattern signature]
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    When checking the actual supplied pattern against the pattern synonym
    signature, we need to be quite careful.

    ----- Provided constraints
    Example

        data T a where
          MkT :: Ord a => a -> T a

        pattern P :: () => Eq a => a -> [T a]
        pattern P x = [MkT x]

    We must check that the (Eq a) that P claims to bind (and to
    make available to matches against P), is derivable from the
    actual pattern.  For example:
        f (P (x::a)) = ...here (Eq a) should be available...
    And yes, (Eq a) is derivable from the (Ord a) bound by P's rhs.

    ----- Existential type variables
    Unusually, we instantiate the existential tyvars of the pattern with
    *meta* type variables.  For example

        data S where
          MkS :: Eq a => [a] -> S

        pattern P :: () => Eq x => x -> S
        pattern P x <- MkS x

    The pattern synonym conceals from its client the fact that MkS has a
    list inside it.  The client just thinks it's a type 'x'.  So we must
    unify x := [a] during type checking, and then use the instantiating type
    [a] (called ex_tys) when building the matcher.  In this case we'll get

       $mP :: S -> (forall x. Ex x => x -> r) -> r -> r
       $mP x k = case x of
                   MkS a (d:Eq a) (ys:[a]) -> let dl :: Eq [a]
                                                  dl = $dfunEqList d
                                              in k [a] dl ys

    All this applies when type-checking the /matching/ side of
    a pattern synonym.  What about the /building/ side?

    * For Unidirectional, there is no builder

    * For ExplicitBidirectional, the builder is completely separate
      code, typechecked in tcPatSynBuilderBind

    * For ImplicitBidirectional, the builder is still typechecked in
      tcPatSynBuilderBind, by converting the pattern to an expression and
      typechecking it.

      At one point, for ImplicitBidirectional I used TyVarTvs (instead of
      TauTvs) in tcCheckPatSynDecl.  But (a) strengthening the check here
      is redundant since tcPatSynBuilderBind does the job, (b) it was
      still incomplete (TyVarTvs can unify with each other), and (c) it
      didn't even work (#13441 was accepted with
      ExplicitBidirectional, but rejected if expressed in
      ImplicitBidirectional form.  Conclusion: trying to be too clever is
      a bad idea.
    -}

    collectPatSynArgInfo :: HsPatSynDetails GhcRn
                         -> ([Name], Bool)
    collectPatSynArgInfo :: HsPatSynDetails GhcRn -> ([Name], Bool)
    collectPatSynArgInfo HsPatSynDetails GhcRn
    details =
      case HsPatSynDetails GhcRn
    details of
        PrefixCon [Void]
    _ [LIdP GhcRn]
    names    -> ((LocatedN Name -> Name) -> [LocatedN Name] -> [Name]
    forall a b. (a -> b) -> [a] -> [b]
    map LocatedN Name -> Name
    forall l e. GenLocated l e -> e
    unLoc [LocatedN Name]
    [LIdP GhcRn]
    names, Bool
    False)
        InfixCon LIdP GhcRn
    name1 LIdP GhcRn
    name2 -> ((LocatedN Name -> Name) -> [LocatedN Name] -> [Name]
    forall a b. (a -> b) -> [a] -> [b]
    map LocatedN Name -> Name
    forall l e. GenLocated l e -> e
    unLoc [LocatedN Name
    LIdP GhcRn
    name1, LocatedN Name
    LIdP GhcRn
    name2], Bool
    True)
        RecCon [RecordPatSynField GhcRn]
    names         -> ((RecordPatSynField GhcRn -> Name)
    -> [RecordPatSynField GhcRn] -> [Name]
    forall a b. (a -> b) -> [a] -> [b]
    map (LocatedN Name -> Name
    forall l e. GenLocated l e -> e
    unLoc (LocatedN Name -> Name)
    -> (RecordPatSynField GhcRn -> LocatedN Name)
    -> RecordPatSynField GhcRn
    -> Name
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . RecordPatSynField GhcRn -> LocatedN Name
    forall pass. RecordPatSynField pass -> LIdP pass
    recordPatSynPatVar) [RecordPatSynField GhcRn]
    names, Bool
    False)

    addPatSynCtxt :: LocatedN Name -> TcM a -> TcM a
    addPatSynCtxt :: forall a. LocatedN Name -> TcM a -> TcM a
    addPatSynCtxt (L SrcSpanAnnN
    loc Name
    name) TcM a
    thing_inside
      = SrcSpanAnnN -> TcM a -> TcM a
    forall ann a. SrcSpanAnn' ann -> TcRn a -> TcRn a
    setSrcSpanA SrcSpanAnnN
    loc (TcM a -> TcM a) -> TcM a -> TcM a
    forall a b. (a -> b) -> a -> b
    $
        SDoc -> TcM a -> TcM a
    forall a. SDoc -> TcM a -> TcM a
    addErrCtxt (String -> SDoc
    text String
    "In the declaration for pattern synonym"
                    SDoc -> SDoc -> SDoc
    <+> SDoc -> SDoc
    quotes (Name -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr Name
    name)) (TcM a -> TcM a) -> TcM a -> TcM a
    forall a b. (a -> b) -> a -> b
    $
        TcM a
    thing_inside

    wrongNumberOfParmsErr :: Name -> Arity -> Arity -> TcM a
    wrongNumberOfParmsErr :: forall a. Name -> Int -> Int -> TcM a
    wrongNumberOfParmsErr Name
    name Int
    decl_arity Int
    missing
      = SDoc -> TcM a
    forall a. SDoc -> TcM a
    failWithTc (SDoc -> TcM a) -> SDoc -> TcM a
    forall a b. (a -> b) -> a -> b
    $
        SDoc -> Int -> SDoc -> SDoc
    hang (String -> SDoc
    text String
    "Pattern synonym" SDoc -> SDoc -> SDoc
    <+> SDoc -> SDoc
    quotes (Name -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr Name
    name) SDoc -> SDoc -> SDoc
    <+> PtrString -> SDoc
    ptext (String -> PtrString
    sLit String
    "has")
              SDoc -> SDoc -> SDoc
    <+> Int -> SDoc -> SDoc
    speakNOf Int
    decl_arity (String -> SDoc
    text String
    "argument"))
           Int
    2 (String -> SDoc
    text String
    "but its type signature has" SDoc -> SDoc -> SDoc
    <+> Int -> SDoc
    int Int
    missing SDoc -> SDoc -> SDoc
    <+> String -> SDoc
    text String
    "fewer arrows")

    -------------------------
    -- Shared by both tcInferPatSyn and tcCheckPatSyn
    tc_patsyn_finish :: LocatedN Name   -- ^ PatSyn Name
                     -> HsPatSynDir GhcRn -- ^ PatSyn type (Uni/Bidir/ExplicitBidir)
                     -> Bool              -- ^ Whether infix
                     -> LPat GhcTc        -- ^ Pattern of the PatSyn
                     -> TcPragEnv
                     -> ([TcInvisTVBinder], [PredType], TcEvBinds, [EvVar])
                     -> ([TcInvisTVBinder], [TcType], [PredType], [EvTerm])
                     -> ([LHsExpr GhcTc], [TcType])  -- ^ Pattern arguments and types
                     -> TcType            -- ^ Pattern type
                     -> [FieldLabel]      -- ^ Selector names
                     -- ^ Whether fields, empty if not record PatSyn
                     -> TcM (LHsBinds GhcTc, TcGblEnv)
    tc_patsyn_finish :: LocatedN Name
    -> HsPatSynDir GhcRn
    -> Bool
    -> LPat GhcTc
    -> TcPragEnv
    -> ([VarBndr Id Specificity], [Kind], TcEvBinds, [Id])
    -> ([VarBndr Id Specificity], [Kind], [Kind], [EvTerm])
    -> ([LHsExpr GhcTc], [Kind])
    -> Kind
    -> [FieldLabel]
    -> TcM (LHsBinds GhcTc, TcGblEnv)
    tc_patsyn_finish LocatedN Name
    lname HsPatSynDir GhcRn
    dir Bool
    is_infix LPat GhcTc
    lpat' TcPragEnv
    prag_fn
                     ([VarBndr Id Specificity]
    univ_tvs, [Kind]
    req_theta, TcEvBinds
    req_ev_binds, [Id]
    req_dicts)
                     ([VarBndr Id Specificity]
    ex_tvs,   [Kind]
    ex_tys,    [Kind]
    prov_theta,   [EvTerm]
    prov_dicts)
                     ([LHsExpr GhcTc]
    args, [Kind]
    arg_tys)
                     Kind
    pat_ty [FieldLabel]
    field_labels
      = do { -- Zonk everything.  We are about to build a final PatSyn
             -- so there had better be no unification variables in there

           ; ZonkEnv
    ze              <- ZonkFlexi -> TcM ZonkEnv
    mkEmptyZonkEnv ZonkFlexi
    NoFlexi
           ; (ZonkEnv
    ze, [VarBndr Id Specificity]
    univ_tvs') <- ZonkEnv
    -> [VarBndr Id Specificity]
    -> TcM (ZonkEnv, [VarBndr Id Specificity])
    forall vis.
    ZonkEnv -> [VarBndr Id vis] -> TcM (ZonkEnv, [VarBndr Id vis])
    zonkTyVarBindersX   ZonkEnv
    ze [VarBndr Id Specificity]
    univ_tvs
           ; [Kind]
    req_theta'      <- ZonkEnv -> [Kind] -> TcM [Kind]
    zonkTcTypesToTypesX ZonkEnv
    ze [Kind]
    req_theta
           ; (ZonkEnv
    ze, [VarBndr Id Specificity]
    ex_tvs')   <- ZonkEnv
    -> [VarBndr Id Specificity]
    -> TcM (ZonkEnv, [VarBndr Id Specificity])
    forall vis.
    ZonkEnv -> [VarBndr Id vis] -> TcM (ZonkEnv, [VarBndr Id vis])
    zonkTyVarBindersX   ZonkEnv
    ze [VarBndr Id Specificity]
    ex_tvs
           ; [Kind]
    prov_theta'     <- ZonkEnv -> [Kind] -> TcM [Kind]
    zonkTcTypesToTypesX ZonkEnv
    ze [Kind]
    prov_theta
           ; Kind
    pat_ty'         <- ZonkEnv -> Kind -> TcM Kind
    zonkTcTypeToTypeX   ZonkEnv
    ze Kind
    pat_ty
           ; [Kind]
    arg_tys'        <- ZonkEnv -> [Kind] -> TcM [Kind]
    zonkTcTypesToTypesX ZonkEnv
    ze [Kind]
    arg_tys

           ; let (TidyEnv
    env1, [VarBndr Id Specificity]
    univ_tvs) = TidyEnv
    -> [VarBndr Id Specificity] -> (TidyEnv, [VarBndr Id Specificity])
    forall vis.
    TidyEnv -> [VarBndr Id vis] -> (TidyEnv, [VarBndr Id vis])
    tidyTyCoVarBinders TidyEnv
    emptyTidyEnv [VarBndr Id Specificity]
    univ_tvs'
                 (TidyEnv
    env2, [VarBndr Id Specificity]
    ex_tvs)   = TidyEnv
    -> [VarBndr Id Specificity] -> (TidyEnv, [VarBndr Id Specificity])
    forall vis.
    TidyEnv -> [VarBndr Id vis] -> (TidyEnv, [VarBndr Id vis])
    tidyTyCoVarBinders TidyEnv
    env1 [VarBndr Id Specificity]
    ex_tvs'
                 req_theta :: [Kind]
    req_theta  = TidyEnv -> [Kind] -> [Kind]
    tidyTypes TidyEnv
    env2 [Kind]
    req_theta'
                 prov_theta :: [Kind]
    prov_theta = TidyEnv -> [Kind] -> [Kind]
    tidyTypes TidyEnv
    env2 [Kind]
    prov_theta'
                 arg_tys :: [Kind]
    arg_tys    = TidyEnv -> [Kind] -> [Kind]
    tidyTypes TidyEnv
    env2 [Kind]
    arg_tys'
                 pat_ty :: Kind
    pat_ty     = TidyEnv -> Kind -> Kind
    tidyType  TidyEnv
    env2 Kind
    pat_ty'

           ; String -> SDoc -> TcRn ()
    traceTc String
    "tc_patsyn_finish {" (SDoc -> TcRn ()) -> SDoc -> TcRn ()
    forall a b. (a -> b) -> a -> b
    $
               Name -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr (LocatedN Name -> Name
    forall l e. GenLocated l e -> e
    unLoc LocatedN Name
    lname) SDoc -> SDoc -> SDoc
    $$ Pat GhcTc -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr (GenLocated SrcSpanAnnA (Pat GhcTc) -> Pat GhcTc
    forall l e. GenLocated l e -> e
    unLoc GenLocated SrcSpanAnnA (Pat GhcTc)
    LPat GhcTc
    lpat') SDoc -> SDoc -> SDoc
    $$
               ([VarBndr Id Specificity], [Kind], TcEvBinds, [Id]) -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr ([VarBndr Id Specificity]
    univ_tvs, [Kind]
    req_theta, TcEvBinds
    req_ev_binds, [Id]
    req_dicts) SDoc -> SDoc -> SDoc
    $$
               ([VarBndr Id Specificity], [Kind], [EvTerm]) -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr ([VarBndr Id Specificity]
    ex_tvs, [Kind]
    prov_theta, [EvTerm]
    prov_dicts) SDoc -> SDoc -> SDoc
    $$
               [LocatedA (HsExpr GhcTc)] -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr [LocatedA (HsExpr GhcTc)]
    [LHsExpr GhcTc]
    args SDoc -> SDoc -> SDoc
    $$
               [Kind] -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr [Kind]
    arg_tys SDoc -> SDoc -> SDoc
    $$
               Kind -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr Kind
    pat_ty

           -- Make the 'matcher'
           ; (PatSynMatcher
    matcher, Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
    matcher_bind) <- LocatedN Name
    -> LPat GhcTc
    -> TcPragEnv
    -> ([Id], [Kind], TcEvBinds, [Id])
    -> ([Id], [Kind], [Kind], [EvTerm])
    -> ([LHsExpr GhcTc], [Kind])
    -> Kind
    -> TcM (PatSynMatcher, LHsBinds GhcTc)
    tcPatSynMatcher LocatedN Name
    lname LPat GhcTc
    lpat' TcPragEnv
    prag_fn
                                             ([VarBndr Id Specificity] -> [Id]
    forall tv argf. [VarBndr tv argf] -> [tv]
    binderVars [VarBndr Id Specificity]
    univ_tvs, [Kind]
    req_theta, TcEvBinds
    req_ev_binds, [Id]
    req_dicts)
                                             ([VarBndr Id Specificity] -> [Id]
    forall tv argf. [VarBndr tv argf] -> [tv]
    binderVars [VarBndr Id Specificity]
    ex_tvs, [Kind]
    ex_tys, [Kind]
    prov_theta, [EvTerm]
    prov_dicts)
                                             ([LHsExpr GhcTc]
    args, [Kind]
    arg_tys)
                                             Kind
    pat_ty

           -- Make the 'builder'
           ; PatSynBuilder
    builder <- HsPatSynDir GhcRn
    -> LocatedN Name
    -> [VarBndr Id Specificity]
    -> [Kind]
    -> [VarBndr Id Specificity]
    -> [Kind]
    -> [Kind]
    -> Kind
    -> TcM PatSynBuilder
    forall a.
    HsPatSynDir a
    -> LocatedN Name
    -> [VarBndr Id Specificity]
    -> [Kind]
    -> [VarBndr Id Specificity]
    -> [Kind]
    -> [Kind]
    -> Kind
    -> TcM PatSynBuilder
    mkPatSynBuilder HsPatSynDir GhcRn
    dir LocatedN Name
    lname
                                        [VarBndr Id Specificity]
    univ_tvs [Kind]
    req_theta
                                        [VarBndr Id Specificity]
    ex_tvs   [Kind]
    prov_theta
                                        [Kind]
    arg_tys Kind
    pat_ty

           -- Make the PatSyn itself
           ; let patSyn :: PatSyn
    patSyn = Name
    -> Bool
    -> ([VarBndr Id Specificity], [Kind])
    -> ([VarBndr Id Specificity], [Kind])
    -> [Kind]
    -> Kind
    -> PatSynMatcher
    -> PatSynBuilder
    -> [FieldLabel]
    -> PatSyn
    mkPatSyn (LocatedN Name -> Name
    forall l e. GenLocated l e -> e
    unLoc LocatedN Name
    lname) Bool
    is_infix
                            ([VarBndr Id Specificity]
    univ_tvs, [Kind]
    req_theta)
                            ([VarBndr Id Specificity]
    ex_tvs, [Kind]
    prov_theta)
                            [Kind]
    arg_tys
                            Kind
    pat_ty
                            PatSynMatcher
    matcher PatSynBuilder
    builder
                            [FieldLabel]
    field_labels

           -- Selectors
           ; FieldSelectors
    has_sel <- DynFlags -> FieldSelectors
    xopt_FieldSelectors (DynFlags -> FieldSelectors)
    -> IOEnv (Env TcGblEnv TcLclEnv) DynFlags
    -> IOEnv (Env TcGblEnv TcLclEnv) FieldSelectors
    forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
    <$> IOEnv (Env TcGblEnv TcLclEnv) DynFlags
    forall (m :: * -> *). HasDynFlags m => m DynFlags
    getDynFlags
           ; let rn_rec_sel_binds :: [(Id, LHsBind GhcRn)]
    rn_rec_sel_binds = PatSyn -> [FieldLabel] -> FieldSelectors -> [(Id, LHsBind GhcRn)]
    mkPatSynRecSelBinds PatSyn
    patSyn (PatSyn -> [FieldLabel]
    patSynFieldLabels PatSyn
    patSyn) FieldSelectors
    has_sel
                 tything :: TyThing
    tything = ConLike -> TyThing
    AConLike (PatSyn -> ConLike
    PatSynCon PatSyn
    patSyn)
           ; TcGblEnv
    tcg_env <- [TyThing] -> TcM TcGblEnv -> TcM TcGblEnv
    forall r. [TyThing] -> TcM r -> TcM r
    tcExtendGlobalEnv [TyThing
    tything] (TcM TcGblEnv -> TcM TcGblEnv) -> TcM TcGblEnv -> TcM TcGblEnv
    forall a b. (a -> b) -> a -> b
    $
                        [(Id, LHsBind GhcRn)] -> TcM TcGblEnv
    tcRecSelBinds [(Id, LHsBind GhcRn)]
    rn_rec_sel_binds

           ; String -> SDoc -> TcRn ()
    traceTc String
    "tc_patsyn_finish }" SDoc
    empty
           ; (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)), TcGblEnv)
    -> TcRn
         (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)), TcGblEnv)
    forall (m :: * -> *) a. Monad m => a -> m a
    return (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
    matcher_bind, TcGblEnv
    tcg_env) }

    {-
    ************************************************************************
    *                                                                      *
             Constructing the "matcher" Id and its binding
    *                                                                      *
    ************************************************************************
    -}

    tcPatSynMatcher :: LocatedN Name
                    -> LPat GhcTc
                    -> TcPragEnv
                    -> ([TcTyVar], ThetaType, TcEvBinds, [EvVar])
                    -> ([TcTyVar], [TcType], ThetaType, [EvTerm])
                    -> ([LHsExpr GhcTc], [TcType])
                    -> TcType
                    -> TcM (PatSynMatcher, LHsBinds GhcTc)
    -- See Note [Matchers and builders for pattern synonyms] in GHC.Core.PatSyn
    tcPatSynMatcher :: LocatedN Name
    -> LPat GhcTc
    -> TcPragEnv
    -> ([Id], [Kind], TcEvBinds, [Id])
    -> ([Id], [Kind], [Kind], [EvTerm])
    -> ([LHsExpr GhcTc], [Kind])
    -> Kind
    -> TcM (PatSynMatcher, LHsBinds GhcTc)
    tcPatSynMatcher (L SrcSpanAnnN
    loc Name
    name) LPat GhcTc
    lpat TcPragEnv
    prag_fn
                    ([Id]
    univ_tvs, [Kind]
    req_theta, TcEvBinds
    req_ev_binds, [Id]
    req_dicts)
                    ([Id]
    ex_tvs, [Kind]
    ex_tys, [Kind]
    prov_theta, [EvTerm]
    prov_dicts)
                    ([LHsExpr GhcTc]
    args, [Kind]
    arg_tys) Kind
    pat_ty
      = do { let loc' :: SrcSpan
    loc' = SrcSpanAnnN -> SrcSpan
    forall a. SrcSpanAnn' a -> SrcSpan
    locA SrcSpanAnnN
    loc
           ; Name
    rr_name <- OccName -> SrcSpan -> TcRnIf TcGblEnv TcLclEnv Name
    newNameAt (String -> OccName
    mkTyVarOcc String
    "rep") SrcSpan
    loc'
           ; Name
    tv_name <- OccName -> SrcSpan -> TcRnIf TcGblEnv TcLclEnv Name
    newNameAt (String -> OccName
    mkTyVarOcc String
    "r")   SrcSpan
    loc'
           ; let rr_tv :: Id
    rr_tv  = Name -> Kind -> Id
    mkTyVar Name
    rr_name Kind
    runtimeRepTy
                 rr :: Kind
    rr     = Id -> Kind
    mkTyVarTy Id
    rr_tv
                 res_tv :: Id
    res_tv = Name -> Kind -> Id
    mkTyVar Name
    tv_name (Kind -> Kind
    tYPE Kind
    rr)
                 res_ty :: Kind
    res_ty = Id -> Kind
    mkTyVarTy Id
    res_tv
                 is_unlifted :: Bool
    is_unlifted = [LocatedA (HsExpr GhcTc)] -> Bool
    forall (t :: * -> *) a. Foldable t => t a -> Bool
    null [LocatedA (HsExpr GhcTc)]
    [LHsExpr GhcTc]
    args Bool -> Bool -> Bool
    && [EvTerm] -> Bool
    forall (t :: * -> *) a. Foldable t => t a -> Bool
    null [EvTerm]
    prov_dicts
                 ([LocatedA (HsExpr GhcTc)]
    cont_args, [Kind]
    cont_arg_tys)
                   | Bool
    is_unlifted = ([IdP GhcTc -> LHsExpr GhcTc
    forall (p :: Pass) a.
    IsSrcSpanAnn p a =>
    IdP (GhcPass p) -> LHsExpr (GhcPass p)
    nlHsVar Id
    IdP GhcTc
    voidPrimId], [Kind
    unboxedUnitTy])
                   | Bool
    otherwise   = ([LocatedA (HsExpr GhcTc)]
    [LHsExpr GhcTc]
    args,                 [Kind]
    arg_tys)
                 cont_ty :: Kind
    cont_ty = [Id] -> [Kind] -> Kind -> Kind
    mkInfSigmaTy [Id]
    ex_tvs [Kind]
    prov_theta (Kind -> Kind) -> Kind -> Kind
    forall a b. (a -> b) -> a -> b
    $
                           [Kind] -> Kind -> Kind
    mkVisFunTysMany [Kind]
    cont_arg_tys Kind
    res_ty

                 fail_ty :: Kind
    fail_ty  = Kind -> Kind -> Kind
    mkVisFunTyMany Kind
    unboxedUnitTy Kind
    res_ty

           ; Name
    matcher_name <- Name -> (OccName -> OccName) -> TcRnIf TcGblEnv TcLclEnv Name
    forall m n. Name -> (OccName -> OccName) -> TcRnIf m n Name
    newImplicitBinder Name
    name OccName -> OccName
    mkMatcherOcc
           ; Id
    scrutinee    <- FastString -> Kind -> Kind -> IOEnv (Env TcGblEnv TcLclEnv) Id
    forall gbl lcl. FastString -> Kind -> Kind -> TcRnIf gbl lcl Id
    newSysLocalId (String -> FastString
    fsLit String
    "scrut") Kind
    Many Kind
    pat_ty
           ; Id
    cont         <- FastString -> Kind -> Kind -> IOEnv (Env TcGblEnv TcLclEnv) Id
    forall gbl lcl. FastString -> Kind -> Kind -> TcRnIf gbl lcl Id
    newSysLocalId (String -> FastString
    fsLit String
    "cont")  Kind
    Many Kind
    cont_ty
           ; Id
    fail         <- FastString -> Kind -> Kind -> IOEnv (Env TcGblEnv TcLclEnv) Id
    forall gbl lcl. FastString -> Kind -> Kind -> TcRnIf gbl lcl Id
    newSysLocalId (String -> FastString
    fsLit String
    "fail")  Kind
    Many Kind
    fail_ty

           ; DynFlags
    dflags       <- IOEnv (Env TcGblEnv TcLclEnv) DynFlags
    forall (m :: * -> *). HasDynFlags m => m DynFlags
    getDynFlags
           ; let matcher_tau :: Kind
    matcher_tau   = [Kind] -> Kind -> Kind
    mkVisFunTysMany [Kind
    pat_ty, Kind
    cont_ty, Kind
    fail_ty] Kind
    res_ty
                 matcher_sigma :: Kind
    matcher_sigma = [Id] -> [Kind] -> Kind -> Kind
    mkInfSigmaTy (Id
    rr_tvId -> [Id] -> [Id]
    forall a. a -> [a] -> [a]
    :Id
    res_tvId -> [Id] -> [Id]
    forall a. a -> [a] -> [a]
    :[Id]
    univ_tvs) [Kind]
    req_theta Kind
    matcher_tau
                 matcher_id :: Id
    matcher_id    = Name -> Kind -> Id
    mkExportedVanillaId Name
    matcher_name Kind
    matcher_sigma
                                 -- See Note [Exported LocalIds] in GHC.Types.Id

                 inst_wrap :: HsWrapper
    inst_wrap = [EvTerm] -> HsWrapper
    mkWpEvApps [EvTerm]
    prov_dicts HsWrapper -> HsWrapper -> HsWrapper
    <.> [Kind] -> HsWrapper
    mkWpTyApps [Kind]
    ex_tys
                 cont' :: LocatedA (HsExpr GhcTc)
    cont' = (LocatedA (HsExpr GhcTc)
     -> LocatedA (HsExpr GhcTc) -> LocatedA (HsExpr GhcTc))
    -> LocatedA (HsExpr GhcTc)
    -> [LocatedA (HsExpr GhcTc)]
    -> LocatedA (HsExpr GhcTc)
    forall (t :: * -> *) b a.
    Foldable t =>
    (b -> a -> b) -> b -> t a -> b
    foldl' LocatedA (HsExpr GhcTc)
    -> LocatedA (HsExpr GhcTc) -> LocatedA (HsExpr GhcTc)
    forall (id :: Pass).
    IsPass id =>
    LHsExpr (GhcPass id)
    -> LHsExpr (GhcPass id) -> LHsExpr (GhcPass id)
    nlHsApp (HsWrapper -> LHsExpr GhcTc -> LHsExpr GhcTc
    mkLHsWrap HsWrapper
    inst_wrap (IdP GhcTc -> LHsExpr GhcTc
    forall (p :: Pass) a.
    IsSrcSpanAnn p a =>
    IdP (GhcPass p) -> LHsExpr (GhcPass p)
    nlHsVar Id
    IdP GhcTc
    cont)) [LocatedA (HsExpr GhcTc)]
    cont_args

                 fail' :: LHsExpr GhcTc
    fail' = IdP GhcTc -> [LHsExpr GhcTc] -> LHsExpr GhcTc
    forall (p :: Pass) a.
    IsSrcSpanAnn p a =>
    IdP (GhcPass p) -> [LHsExpr (GhcPass p)] -> LHsExpr (GhcPass p)
    nlHsApps Id
    IdP GhcTc
    fail [IdP GhcTc -> LHsExpr GhcTc
    forall (p :: Pass) a.
    IsSrcSpanAnn p a =>
    IdP (GhcPass p) -> LHsExpr (GhcPass p)
    nlHsVar Id
    IdP GhcTc
    voidPrimId]

                 args :: [GenLocated SrcSpanAnnA (Pat GhcTc)]
    args = (Id -> GenLocated SrcSpanAnnA (Pat GhcTc))
    -> [Id] -> [GenLocated SrcSpanAnnA (Pat GhcTc)]
    forall a b. (a -> b) -> [a] -> [b]
    map Id -> GenLocated SrcSpanAnnA (Pat GhcTc)
    forall (p :: Pass) a.
    IsSrcSpanAnn p a =>
    IdP (GhcPass p) -> LPat (GhcPass p)
    nlVarPat [Id
    scrutinee, Id
    cont, Id
    fail]
                 lwpat :: GenLocated SrcSpanAnnA (Pat GhcTc)
    lwpat = Pat GhcTc -> GenLocated SrcSpanAnnA (Pat GhcTc)
    forall a an. a -> LocatedAn an a
    noLocA (Pat GhcTc -> GenLocated SrcSpanAnnA (Pat GhcTc))
    -> Pat GhcTc -> GenLocated SrcSpanAnnA (Pat GhcTc)
    forall a b. (a -> b) -> a -> b
    $ XWildPat GhcTc -> Pat GhcTc
    forall p. XWildPat p -> Pat p
    WildPat Kind
    XWildPat GhcTc
    pat_ty
                 cases :: [GenLocated SrcSpanAnnA (Match GhcTc (LocatedA (HsExpr GhcTc)))]
    cases = if DynFlags -> LPat GhcTc -> Bool
    forall (p :: Pass).
    OutputableBndrId p =>
    DynFlags -> LPat (GhcPass p) -> Bool
    isIrrefutableHsPat DynFlags
    dflags LPat GhcTc
    lpat
                         then [LPat GhcTc
    -> LocatedA (HsExpr GhcTc)
    -> LMatch GhcTc (LocatedA (HsExpr GhcTc))
    forall (p :: Pass) (body :: * -> *).
    (Anno (GRHS (GhcPass p) (LocatedA (body (GhcPass p)))) ~ SrcSpan,
     Anno (Match (GhcPass p) (LocatedA (body (GhcPass p))))
     ~ SrcSpanAnnA) =>
    LPat (GhcPass p)
    -> LocatedA (body (GhcPass p))
    -> LMatch (GhcPass p) (LocatedA (body (GhcPass p)))
    mkHsCaseAlt LPat GhcTc
    lpat  LocatedA (HsExpr GhcTc)
    cont']
                         else [LPat GhcTc
    -> LocatedA (HsExpr GhcTc)
    -> LMatch GhcTc (LocatedA (HsExpr GhcTc))
    forall (p :: Pass) (body :: * -> *).
    (Anno (GRHS (GhcPass p) (LocatedA (body (GhcPass p)))) ~ SrcSpan,
     Anno (Match (GhcPass p) (LocatedA (body (GhcPass p))))
     ~ SrcSpanAnnA) =>
    LPat (GhcPass p)
    -> LocatedA (body (GhcPass p))
    -> LMatch (GhcPass p) (LocatedA (body (GhcPass p)))
    mkHsCaseAlt LPat GhcTc
    lpat  LocatedA (HsExpr GhcTc)
    cont',
                               LPat GhcTc
    -> LocatedA (HsExpr GhcTc)
    -> LMatch GhcTc (LocatedA (HsExpr GhcTc))
    forall (p :: Pass) (body :: * -> *).
    (Anno (GRHS (GhcPass p) (LocatedA (body (GhcPass p)))) ~ SrcSpan,
     Anno (Match (GhcPass p) (LocatedA (body (GhcPass p))))
     ~ SrcSpanAnnA) =>
    LPat (GhcPass p)
    -> LocatedA (body (GhcPass p))
    -> LMatch (GhcPass p) (LocatedA (body (GhcPass p)))
    mkHsCaseAlt GenLocated SrcSpanAnnA (Pat GhcTc)
    LPat GhcTc
    lwpat LocatedA (HsExpr GhcTc)
    LHsExpr GhcTc
    fail']
                 body :: LHsExpr GhcTc
    body = HsWrapper -> LHsExpr GhcTc -> LHsExpr GhcTc
    mkLHsWrap (TcEvBinds -> HsWrapper
    mkWpLet TcEvBinds
    req_ev_binds) (LHsExpr GhcTc -> LHsExpr GhcTc) -> LHsExpr GhcTc -> LHsExpr GhcTc
    forall a b. (a -> b) -> a -> b
    $
                        SrcSpanAnnA -> HsExpr GhcTc -> LocatedA (HsExpr GhcTc)
    forall l e. l -> e -> GenLocated l e
    L (GenLocated SrcSpanAnnA (Pat GhcTc) -> SrcSpanAnnA
    forall l e. GenLocated l e -> l
    getLoc GenLocated SrcSpanAnnA (Pat GhcTc)
    LPat GhcTc
    lpat) (HsExpr GhcTc -> LocatedA (HsExpr GhcTc))
    -> HsExpr GhcTc -> LocatedA (HsExpr GhcTc)
    forall a b. (a -> b) -> a -> b
    $
                        XCase GhcTc
    -> LHsExpr GhcTc
    -> MatchGroup GhcTc (LHsExpr GhcTc)
    -> HsExpr GhcTc
    forall p.
    XCase p -> LHsExpr p -> MatchGroup p (LHsExpr p) -> HsExpr p
    HsCase NoExtField
    XCase GhcTc
    noExtField (IdP GhcTc -> LHsExpr GhcTc
    forall (p :: Pass) a.
    IsSrcSpanAnn p a =>
    IdP (GhcPass p) -> LHsExpr (GhcPass p)
    nlHsVar Id
    IdP GhcTc
    scrutinee) (MatchGroup GhcTc (LHsExpr GhcTc) -> HsExpr GhcTc)
    -> MatchGroup GhcTc (LHsExpr GhcTc) -> HsExpr GhcTc
    forall a b. (a -> b) -> a -> b
    $
                        MG{ mg_alts :: XRec GhcTc [LMatch GhcTc (LocatedA (HsExpr GhcTc))]
    mg_alts = SrcSpanAnnL
    -> [GenLocated SrcSpanAnnA (Match GhcTc (LocatedA (HsExpr GhcTc)))]
    -> GenLocated
         SrcSpanAnnL
         [GenLocated SrcSpanAnnA (Match GhcTc (LocatedA (HsExpr GhcTc)))]
    forall l e. l -> e -> GenLocated l e
    L (SrcSpanAnnA -> SrcSpanAnnL
    forall a ann. SrcSpanAnn' a -> SrcAnn ann
    l2l (SrcSpanAnnA -> SrcSpanAnnL) -> SrcSpanAnnA -> SrcSpanAnnL
    forall a b. (a -> b) -> a -> b
    $ GenLocated SrcSpanAnnA (Pat GhcTc) -> SrcSpanAnnA
    forall l e. GenLocated l e -> l
    getLoc GenLocated SrcSpanAnnA (Pat GhcTc)
    LPat GhcTc
    lpat) [GenLocated SrcSpanAnnA (Match GhcTc (LocatedA (HsExpr GhcTc)))]
    cases
                          , mg_ext :: XMG GhcTc (LocatedA (HsExpr GhcTc))
    mg_ext = [Scaled Kind] -> Kind -> MatchGroupTc
    MatchGroupTc [Kind -> Scaled Kind
    forall a. a -> Scaled a
    unrestricted Kind
    pat_ty] Kind
    res_ty
                          , mg_origin :: Origin
    mg_origin = Origin
    Generated
                          }
                 body' :: LocatedA (HsExpr GhcTc)
    body' = HsExpr GhcTc -> LocatedA (HsExpr GhcTc)
    forall a an. a -> LocatedAn an a
    noLocA (HsExpr GhcTc -> LocatedA (HsExpr GhcTc))
    -> HsExpr GhcTc -> LocatedA (HsExpr GhcTc)
    forall a b. (a -> b) -> a -> b
    $
                         XLam GhcTc -> MatchGroup GhcTc (LHsExpr GhcTc) -> HsExpr GhcTc
    forall p. XLam p -> MatchGroup p (LHsExpr p) -> HsExpr p
    HsLam NoExtField
    XLam GhcTc
    noExtField (MatchGroup GhcTc (LHsExpr GhcTc) -> HsExpr GhcTc)
    -> MatchGroup GhcTc (LHsExpr GhcTc) -> HsExpr GhcTc
    forall a b. (a -> b) -> a -> b
    $
                         MG{ mg_alts :: XRec GhcTc [LMatch GhcTc (LocatedA (HsExpr GhcTc))]
    mg_alts = [LMatch GhcTc (LocatedA (HsExpr GhcTc))]
    -> LocatedAn AnnList [LMatch GhcTc (LocatedA (HsExpr GhcTc))]
    forall a an. a -> LocatedAn an a
    noLocA [HsMatchContext (NoGhcTc GhcTc)
    -> [LPat GhcTc]
    -> LocatedA (HsExpr GhcTc)
    -> LMatch GhcTc (LocatedA (HsExpr GhcTc))
    forall (p :: Pass) (body :: * -> *).
    (Anno (Match (GhcPass p) (LocatedA (body (GhcPass p))))
     ~ SrcSpanAnnA,
     Anno (GRHS (GhcPass p) (LocatedA (body (GhcPass p)))) ~ SrcSpan) =>
    HsMatchContext (NoGhcTc (GhcPass p))
    -> [LPat (GhcPass p)]
    -> LocatedA (body (GhcPass p))
    -> LMatch (GhcPass p) (LocatedA (body (GhcPass p)))
    mkSimpleMatch HsMatchContext (NoGhcTc GhcTc)
    forall p. HsMatchContext p
    LambdaExpr
                                                             [GenLocated SrcSpanAnnA (Pat GhcTc)]
    [LPat GhcTc]
    args LocatedA (HsExpr GhcTc)
    LHsExpr GhcTc
    body]
                           , mg_ext :: XMG GhcTc (LocatedA (HsExpr GhcTc))
    mg_ext = [Scaled Kind] -> Kind -> MatchGroupTc
    MatchGroupTc ((Kind -> Scaled Kind) -> [Kind] -> [Scaled Kind]
    forall a b. (a -> b) -> [a] -> [b]
    map Kind -> Scaled Kind
    forall a. a -> Scaled a
    unrestricted [Kind
    pat_ty, Kind
    cont_ty, Kind
    fail_ty]) Kind
    res_ty
                           , mg_origin :: Origin
    mg_origin = Origin
    Generated
                           }
                 match :: LMatch GhcTc (LHsExpr GhcTc)
    match = HsMatchContext (NoGhcTc GhcTc)
    -> [LPat GhcTc]
    -> LHsExpr GhcTc
    -> HsLocalBinds GhcTc
    -> LMatch GhcTc (LHsExpr GhcTc)
    forall (p :: Pass).
    IsPass p =>
    HsMatchContext (NoGhcTc (GhcPass p))
    -> [LPat (GhcPass p)]
    -> LHsExpr (GhcPass p)
    -> HsLocalBinds (GhcPass p)
    -> LMatch (GhcPass p) (LHsExpr (GhcPass p))
    mkMatch (LIdP (GhcPass (NoGhcTcPass 'Typechecked))
    -> HsMatchContext (GhcPass (NoGhcTcPass 'Typechecked))
    forall p. LIdP p -> HsMatchContext p
    mkPrefixFunRhs (SrcSpanAnnN -> Name -> LocatedN Name
    forall l e. l -> e -> GenLocated l e
    L SrcSpanAnnN
    loc Name
    name)) []
                                 ([Id] -> [Id] -> LHsExpr GhcTc -> LHsExpr GhcTc
    mkHsLams (Id
    rr_tvId -> [Id] -> [Id]
    forall a. a -> [a] -> [a]
    :Id
    res_tvId -> [Id] -> [Id]
    forall a. a -> [a] -> [a]
    :[Id]
    univ_tvs)
                                           [Id]
    req_dicts LocatedA (HsExpr GhcTc)
    LHsExpr GhcTc
    body')
                                 (XEmptyLocalBinds GhcTc GhcTc -> HsLocalBinds GhcTc
    forall idL idR. XEmptyLocalBinds idL idR -> HsLocalBindsLR idL idR
    EmptyLocalBinds NoExtField
    XEmptyLocalBinds GhcTc GhcTc
    noExtField)
                 mg :: MatchGroup GhcTc (LHsExpr GhcTc)
                 mg :: MatchGroup GhcTc (LHsExpr GhcTc)
    mg = MG{ mg_alts :: XRec GhcTc [LMatch GhcTc (LocatedA (HsExpr GhcTc))]
    mg_alts = SrcSpanAnnL
    -> [GenLocated
          (Anno (Match GhcTc (LocatedA (HsExpr GhcTc))))
          (Match GhcTc (LocatedA (HsExpr GhcTc)))]
    -> GenLocated
         SrcSpanAnnL
         [GenLocated
            (Anno (Match GhcTc (LocatedA (HsExpr GhcTc))))
            (Match GhcTc (LocatedA (HsExpr GhcTc)))]
    forall l e. l -> e -> GenLocated l e
    L (SrcSpanAnnA -> SrcSpanAnnL
    forall a ann. SrcSpanAnn' a -> SrcAnn ann
    l2l (SrcSpanAnnA -> SrcSpanAnnL) -> SrcSpanAnnA -> SrcSpanAnnL
    forall a b. (a -> b) -> a -> b
    $ GenLocated SrcSpanAnnA (Match GhcTc (LocatedA (HsExpr GhcTc)))
    -> SrcSpanAnnA
    forall l e. GenLocated l e -> l
    getLoc GenLocated SrcSpanAnnA (Match GhcTc (LocatedA (HsExpr GhcTc)))
    LMatch GhcTc (LHsExpr GhcTc)
    match) [GenLocated
      (Anno (Match GhcTc (LocatedA (HsExpr GhcTc))))
      (Match GhcTc (LocatedA (HsExpr GhcTc)))
    LMatch GhcTc (LHsExpr GhcTc)
    match]
                        , mg_ext :: XMG GhcTc (LocatedA (HsExpr GhcTc))
    mg_ext = [Scaled Kind] -> Kind -> MatchGroupTc
    MatchGroupTc [] Kind
    res_ty
                        , mg_origin :: Origin
    mg_origin = Origin
    Generated
                        }
                 prags :: [LSig GhcRn]
    prags = TcPragEnv -> Name -> [LSig GhcRn]
    lookupPragEnv TcPragEnv
    prag_fn Name
    name
                 -- See Note [Pragmas for pattern synonyms]

           ; Id
    matcher_prag_id <- Id -> [LSig GhcRn] -> IOEnv (Env TcGblEnv TcLclEnv) Id
    addInlinePrags Id
    matcher_id [LSig GhcRn]
    prags
           ; let bind :: HsBindLR GhcTc GhcTc
    bind = FunBind{ fun_id :: LIdP GhcTc
    fun_id = SrcSpanAnnN -> Id -> GenLocated SrcSpanAnnN Id
    forall l e. l -> e -> GenLocated l e
    L SrcSpanAnnN
    loc Id
    matcher_prag_id
                               , fun_matches :: MatchGroup GhcTc (LHsExpr GhcTc)
    fun_matches = MatchGroup GhcTc (LHsExpr GhcTc)
    mg
                               , fun_ext :: XFunBind GhcTc GhcTc
    fun_ext = XFunBind GhcTc GhcTc
    HsWrapper
    idHsWrapper
                               , fun_tick :: [CoreTickish]
    fun_tick = [] }
                 matcher_bind :: Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
    matcher_bind = GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)
    -> Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
    forall a. a -> Bag a
    unitBag (HsBindLR GhcTc GhcTc
    -> GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)
    forall a an. a -> LocatedAn an a
    noLocA HsBindLR GhcTc GhcTc
    bind)
           ; String -> SDoc -> TcRn ()
    traceTc String
    "tcPatSynMatcher" (Name -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr Name
    name SDoc -> SDoc -> SDoc
    $$ Kind -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr (Id -> Kind
    idType Id
    matcher_id))
           ; String -> SDoc -> TcRn ()
    traceTc String
    "tcPatSynMatcher" (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)) -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
    matcher_bind)

           ; (PatSynMatcher,
     Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))
    -> IOEnv
         (Env TcGblEnv TcLclEnv)
         (PatSynMatcher,
          Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))
    forall (m :: * -> *) a. Monad m => a -> m a
    return ((Name
    matcher_name, Kind
    matcher_sigma, Bool
    is_unlifted), Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
    matcher_bind) }

    mkPatSynRecSelBinds :: PatSyn
                        -> [FieldLabel]  -- ^ Visible field labels
                        -> FieldSelectors
                        -> [(Id, LHsBind GhcRn)]
    mkPatSynRecSelBinds :: PatSyn -> [FieldLabel] -> FieldSelectors -> [(Id, LHsBind GhcRn)]
    mkPatSynRecSelBinds PatSyn
    ps [FieldLabel]
    fields FieldSelectors
    has_sel
      = [ [ConLike]
    -> RecSelParent
    -> FieldLabel
    -> FieldSelectors
    -> (Id, LHsBind GhcRn)
    mkOneRecordSelector [PatSyn -> ConLike
    PatSynCon PatSyn
    ps] (PatSyn -> RecSelParent
    RecSelPatSyn PatSyn
    ps) FieldLabel
    fld_lbl FieldSelectors
    has_sel
        | FieldLabel
    fld_lbl <- [FieldLabel]
    fields ]

    isUnidirectional :: HsPatSynDir a -> Bool
    isUnidirectional :: forall a. HsPatSynDir a -> Bool
    isUnidirectional HsPatSynDir a
    Unidirectional          = Bool
    True
    isUnidirectional HsPatSynDir a
    ImplicitBidirectional   = Bool
    False
    isUnidirectional ExplicitBidirectional{} = Bool
    False

    {-
    ************************************************************************
    *                                                                      *
             Constructing the "builder" Id
    *                                                                      *
    ************************************************************************
    -}

    mkPatSynBuilder :: HsPatSynDir a -> LocatedN Name
                    -> [InvisTVBinder] -> ThetaType
                    -> [InvisTVBinder] -> ThetaType
                    -> [Type] -> Type
                    -> TcM PatSynBuilder
    mkPatSynBuilder :: forall a.
    HsPatSynDir a
    -> LocatedN Name
    -> [VarBndr Id Specificity]
    -> [Kind]
    -> [VarBndr Id Specificity]
    -> [Kind]
    -> [Kind]
    -> Kind
    -> TcM PatSynBuilder
    mkPatSynBuilder HsPatSynDir a
    dir (L SrcSpanAnnN
    _ Name
    name)
                      [VarBndr Id Specificity]
    univ_bndrs [Kind]
    req_theta [VarBndr Id Specificity]
    ex_bndrs [Kind]
    prov_theta
                      [Kind]
    arg_tys Kind
    pat_ty
      | HsPatSynDir a -> Bool
    forall a. HsPatSynDir a -> Bool
    isUnidirectional HsPatSynDir a
    dir
      = PatSynBuilder -> TcM PatSynBuilder
    forall (m :: * -> *) a. Monad m => a -> m a
    return PatSynBuilder
    forall a. Maybe a
    Nothing
      | Bool
    otherwise
      = do { Name
    builder_name <- Name -> (OccName -> OccName) -> TcRnIf TcGblEnv TcLclEnv Name
    forall m n. Name -> (OccName -> OccName) -> TcRnIf m n Name
    newImplicitBinder Name
    name OccName -> OccName
    mkBuilderOcc
           ; let theta :: [Kind]
    theta          = [Kind]
    req_theta [Kind] -> [Kind] -> [Kind]
    forall a. [a] -> [a] -> [a]
    ++ [Kind]
    prov_theta
                 need_dummy_arg :: Bool
    need_dummy_arg = HasDebugCallStack => Kind -> Bool
    Kind -> Bool
    isUnliftedType Kind
    pat_ty Bool -> Bool -> Bool
    && [Kind] -> Bool
    forall (t :: * -> *) a. Foldable t => t a -> Bool
    null [Kind]
    arg_tys Bool -> Bool -> Bool
    && [Kind] -> Bool
    forall (t :: * -> *) a. Foldable t => t a -> Bool
    null [Kind]
    theta
                 builder_sigma :: Kind
    builder_sigma  = Bool -> Kind -> Kind
    add_void Bool
    need_dummy_arg (Kind -> Kind) -> Kind -> Kind
    forall a b. (a -> b) -> a -> b
    $
                                  [VarBndr Id Specificity] -> Kind -> Kind
    mkInvisForAllTys [VarBndr Id Specificity]
    univ_bndrs (Kind -> Kind) -> Kind -> Kind
    forall a b. (a -> b) -> a -> b
    $
                                  [VarBndr Id Specificity] -> Kind -> Kind
    mkInvisForAllTys [VarBndr Id Specificity]
    ex_bndrs (Kind -> Kind) -> Kind -> Kind
    forall a b. (a -> b) -> a -> b
    $
                                  [Kind] -> Kind -> Kind
    mkPhiTy [Kind]
    theta (Kind -> Kind) -> Kind -> Kind
    forall a b. (a -> b) -> a -> b
    $
                                  [Kind] -> Kind -> Kind
    mkVisFunTysMany [Kind]
    arg_tys (Kind -> Kind) -> Kind -> Kind
    forall a b. (a -> b) -> a -> b
    $
                                  Kind
    pat_ty
           ; PatSynBuilder -> TcM PatSynBuilder
    forall (m :: * -> *) a. Monad m => a -> m a
    return (PatSynMatcher -> PatSynBuilder
    forall a. a -> Maybe a
    Just (Name
    builder_name, Kind
    builder_sigma, Bool
    need_dummy_arg)) }

    tcPatSynBuilderBind :: TcPragEnv
                        -> PatSynBind GhcRn GhcRn
                        -> TcM (LHsBinds GhcTc)
    -- See Note [Matchers and builders for pattern synonyms] in GHC.Core.PatSyn
    tcPatSynBuilderBind :: TcPragEnv -> PatSynBind GhcRn GhcRn -> TcM (LHsBinds GhcTc)
    tcPatSynBuilderBind TcPragEnv
    prag_fn (PSB { psb_id :: forall idL idR. PatSynBind idL idR -> LIdP idL
    psb_id = ps_lname :: LIdP GhcRn
    ps_lname@(L SrcSpanAnnN
    loc Name
    ps_name)
                                     , psb_def :: forall idL idR. PatSynBind idL idR -> LPat idR
    psb_def = LPat GhcRn
    lpat
                                     , psb_dir :: forall idL idR. PatSynBind idL idR -> HsPatSynDir idR
    psb_dir = HsPatSynDir GhcRn
    dir
                                     , psb_args :: forall idL idR. PatSynBind idL idR -> HsPatSynDetails idR
    psb_args = HsPatSynDetails GhcRn
    details })
      | HsPatSynDir GhcRn -> Bool
    forall a. HsPatSynDir a -> Bool
    isUnidirectional HsPatSynDir GhcRn
    dir
      = Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
    -> IOEnv
         (Env TcGblEnv TcLclEnv)
         (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))
    forall (m :: * -> *) a. Monad m => a -> m a
    return Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
    forall a. Bag a
    emptyBag

      | Left SDoc
    why <- Either
      SDoc (MatchGroup GhcRn (GenLocated SrcSpanAnnA (HsExpr GhcRn)))
    mb_match_group       -- Can't invert the pattern
      = SrcSpan -> TcM (LHsBinds GhcTc) -> TcM (LHsBinds GhcTc)
    forall a. SrcSpan -> TcRn a -> TcRn a
    setSrcSpan (GenLocated SrcSpanAnnA (Pat GhcRn) -> SrcSpan
    forall a e. GenLocated (SrcSpanAnn' a) e -> SrcSpan
    getLocA GenLocated SrcSpanAnnA (Pat GhcRn)
    LPat GhcRn
    lpat) (TcM (LHsBinds GhcTc) -> TcM (LHsBinds GhcTc))
    -> TcM (LHsBinds GhcTc) -> TcM (LHsBinds GhcTc)
    forall a b. (a -> b) -> a -> b
    $ SDoc -> TcM (LHsBinds GhcTc)
    forall a. SDoc -> TcM a
    failWithTc (SDoc -> TcM (LHsBinds GhcTc)) -> SDoc -> TcM (LHsBinds GhcTc)
    forall a b. (a -> b) -> a -> b
    $
        [SDoc] -> SDoc
    vcat [ SDoc -> Int -> SDoc -> SDoc
    hang (String -> SDoc
    text String
    "Invalid right-hand side of bidirectional pattern synonym"
                     SDoc -> SDoc -> SDoc
    <+> SDoc -> SDoc
    quotes (Name -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr Name
    ps_name) SDoc -> SDoc -> SDoc
    <> SDoc
    colon)
                  Int
    2 SDoc
    why
             , String -> SDoc
    text String
    "RHS pattern:" SDoc -> SDoc -> SDoc
    <+> GenLocated SrcSpanAnnA (Pat GhcRn) -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr GenLocated SrcSpanAnnA (Pat GhcRn)
    LPat GhcRn
    lpat ]

      | Right MatchGroup GhcRn (GenLocated SrcSpanAnnA (HsExpr GhcRn))
    match_group <- Either
      SDoc (MatchGroup GhcRn (GenLocated SrcSpanAnnA (HsExpr GhcRn)))
    mb_match_group  -- Bidirectional
      = do { PatSyn
    patsyn <- Name -> TcM PatSyn
    tcLookupPatSyn Name
    ps_name
           ; case PatSyn -> PatSynBuilder
    patSynBuilder PatSyn
    patsyn of {
               PatSynBuilder
    Nothing -> Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
    -> IOEnv
         (Env TcGblEnv TcLclEnv)
         (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))
    forall (m :: * -> *) a. Monad m => a -> m a
    return Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
    forall a. Bag a
    emptyBag ;
                 -- This case happens if we found a type error in the
                 -- pattern synonym, recovered, and put a placeholder
                 -- with patSynBuilder=Nothing in the environment

               Just (Name
    builder_name, Kind
    builder_ty, Bool
    need_dummy_arg) ->  -- Normal case
        do { -- Bidirectional, so patSynBuilder returns Just
             let pat_ty :: Kind
    pat_ty = PatSyn -> Kind
    patSynResultType PatSyn
    patsyn
                 builder_id :: Id
    builder_id = HasDebugCallStack => (IdInfo -> IdInfo) -> Id -> Id
    (IdInfo -> IdInfo) -> Id -> Id
    modifyIdInfo (IdInfo -> Kind -> IdInfo
    `setLevityInfoWithType` Kind
    pat_ty) (Id -> Id) -> Id -> Id
    forall a b. (a -> b) -> a -> b
    $
                              Name -> Kind -> Id
    mkExportedVanillaId Name
    builder_name Kind
    builder_ty
                             -- See Note [Exported LocalIds] in GHC.Types.Id
                 prags :: [LSig GhcRn]
    prags = TcPragEnv -> Name -> [LSig GhcRn]
    lookupPragEnv TcPragEnv
    prag_fn Name
    ps_name
                 -- See Note [Pragmas for pattern synonyms]
                 -- Keyed by the PatSyn Name, not the (internal) builder name

           ; Id
    builder_id <- Id -> [LSig GhcRn] -> IOEnv (Env TcGblEnv TcLclEnv) Id
    addInlinePrags Id
    builder_id [LSig GhcRn]
    prags

           ; let match_group' :: MatchGroup GhcRn (LHsExpr GhcRn)
    match_group' | Bool
    need_dummy_arg = MatchGroup GhcRn (LHsExpr GhcRn)
    -> MatchGroup GhcRn (LHsExpr GhcRn)
    add_dummy_arg MatchGroup GhcRn (GenLocated SrcSpanAnnA (HsExpr GhcRn))
    MatchGroup GhcRn (LHsExpr GhcRn)
    match_group
                              | Bool
    otherwise      = MatchGroup GhcRn (GenLocated SrcSpanAnnA (HsExpr GhcRn))
    MatchGroup GhcRn (LHsExpr GhcRn)
    match_group

                 bind :: HsBindLR GhcRn GhcRn
    bind = FunBind { fun_id :: LIdP GhcRn
    fun_id      = SrcSpanAnnN -> Name -> LocatedN Name
    forall l e. l -> e -> GenLocated l e
    L SrcSpanAnnN
    loc (Id -> Name
    idName Id
    builder_id)
                                , fun_matches :: MatchGroup GhcRn (LHsExpr GhcRn)
    fun_matches = MatchGroup GhcRn (LHsExpr GhcRn)
    match_group'
                                , fun_ext :: XFunBind GhcRn GhcRn
    fun_ext     = NameSet
    XFunBind GhcRn GhcRn
    emptyNameSet
                                , fun_tick :: [CoreTickish]
    fun_tick    = [] }

                 sig :: TcIdSigInfo
    sig = UserTypeCtxt -> Id -> TcIdSigInfo
    completeSigFromId (Name -> UserTypeCtxt
    PatSynCtxt Name
    ps_name) Id
    builder_id

           ; String -> SDoc -> TcRn ()
    traceTc String
    "tcPatSynBuilderBind {" (SDoc -> TcRn ()) -> SDoc -> TcRn ()
    forall a b. (a -> b) -> a -> b
    $
             [SDoc] -> SDoc
    vcat [ PatSyn -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr PatSyn
    patsyn
                  , Id -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr Id
    builder_id SDoc -> SDoc -> SDoc
    <+> SDoc
    dcolon SDoc -> SDoc -> SDoc
    <+> Kind -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr (Id -> Kind
    idType Id
    builder_id)
                  , [GenLocated SrcSpanAnnA (Sig GhcRn)] -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr [GenLocated SrcSpanAnnA (Sig GhcRn)]
    [LSig GhcRn]
    prags ]
           ; (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
    builder_binds, [Id]
    _) <- TcPragEnv
    -> TcIdSigInfo -> LHsBind GhcRn -> TcM (LHsBinds GhcTc, [Id])
    tcPolyCheck TcPragEnv
    emptyPragEnv TcIdSigInfo
    sig (HsBindLR GhcRn GhcRn
    -> LocatedAn AnnListItem (HsBindLR GhcRn GhcRn)
    forall a an. a -> LocatedAn an a
    noLocA HsBindLR GhcRn GhcRn
    bind)
           ; String -> SDoc -> TcRn ()
    traceTc String
    "tcPatSynBuilderBind }" (SDoc -> TcRn ()) -> SDoc -> TcRn ()
    forall a b. (a -> b) -> a -> b
    $ Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)) -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
    builder_binds
           ; Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
    -> IOEnv
         (Env TcGblEnv TcLclEnv)
         (Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc)))
    forall (m :: * -> *) a. Monad m => a -> m a
    return Bag (GenLocated SrcSpanAnnA (HsBindLR GhcTc GhcTc))
    builder_binds } } }

    #if __GLASGOW_HASKELL__ <= 810
      | otherwise = panic "tcPatSynBuilderBind"  -- Both cases dealt with
    #endif
      where
        mb_match_group :: Either
      SDoc (MatchGroup GhcRn (GenLocated SrcSpanAnnA (HsExpr GhcRn)))
    mb_match_group
           = case HsPatSynDir GhcRn
    dir of
               ExplicitBidirectional MatchGroup GhcRn (LHsExpr GhcRn)
    explicit_mg -> MatchGroup GhcRn (GenLocated SrcSpanAnnA (HsExpr GhcRn))
    -> Either
         SDoc (MatchGroup GhcRn (GenLocated SrcSpanAnnA (HsExpr GhcRn)))
    forall a b. b -> Either a b
    Right MatchGroup GhcRn (GenLocated SrcSpanAnnA (HsExpr GhcRn))
    MatchGroup GhcRn (LHsExpr GhcRn)
    explicit_mg
               HsPatSynDir GhcRn
    ImplicitBidirectional -> (GenLocated SrcSpanAnnA (HsExpr GhcRn)
     -> MatchGroup GhcRn (GenLocated SrcSpanAnnA (HsExpr GhcRn)))
    -> Either SDoc (GenLocated SrcSpanAnnA (HsExpr GhcRn))
    -> Either
         SDoc (MatchGroup GhcRn (GenLocated SrcSpanAnnA (HsExpr GhcRn)))
    forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
    fmap GenLocated SrcSpanAnnA (HsExpr GhcRn)
    -> MatchGroup GhcRn (GenLocated SrcSpanAnnA (HsExpr GhcRn))
    LHsExpr GhcRn -> MatchGroup GhcRn (LHsExpr GhcRn)
    mk_mg (Name
    -> [LocatedN Name] -> LPat GhcRn -> Either SDoc (LHsExpr GhcRn)
    tcPatToExpr Name
    ps_name [LocatedN Name]
    [LIdP GhcRn]
    args LPat GhcRn
    lpat)
               HsPatSynDir GhcRn
    Unidirectional -> String
    -> Either
         SDoc (MatchGroup GhcRn (GenLocated SrcSpanAnnA (HsExpr GhcRn)))
    forall a. String -> a
    panic String
    "tcPatSynBuilderBind"

        mk_mg :: LHsExpr GhcRn -> MatchGroup GhcRn (LHsExpr GhcRn)
        mk_mg :: LHsExpr GhcRn -> MatchGroup GhcRn (LHsExpr GhcRn)
    mk_mg LHsExpr GhcRn
    body = Origin
    -> LocatedL
         [LocatedA (Match GhcRn (GenLocated SrcSpanAnnA (HsExpr GhcRn)))]
    -> MatchGroup GhcRn (GenLocated SrcSpanAnnA (HsExpr GhcRn))
    forall (p :: Pass) (body :: * -> *).
    AnnoBody p body =>
    Origin
    -> LocatedL
         [LocatedA (Match (GhcPass p) (LocatedA (body (GhcPass p))))]
    -> MatchGroup (GhcPass p) (LocatedA (body (GhcPass p)))
    mkMatchGroup Origin
    Generated ([LocatedA (Match GhcRn (GenLocated SrcSpanAnnA (HsExpr GhcRn)))]
    -> LocatedL
         [LocatedA (Match GhcRn (GenLocated SrcSpanAnnA (HsExpr GhcRn)))]
    forall a an. a -> LocatedAn an a
    noLocA [LocatedA (Match GhcRn (GenLocated SrcSpanAnnA (HsExpr GhcRn)))
    LMatch GhcRn (LHsExpr GhcRn)
    builder_match])
              where
                builder_args :: [GenLocated SrcSpanAnnA (Pat GhcRn)]
    builder_args  = [SrcSpanAnnA -> Pat GhcRn -> GenLocated SrcSpanAnnA (Pat GhcRn)
    forall l e. l -> e -> GenLocated l e
    L (SrcSpanAnnN -> SrcSpanAnnA
    forall a ann. SrcSpanAnn' a -> SrcAnn ann
    na2la SrcSpanAnnN
    loc) (XVarPat GhcRn -> LIdP GhcRn -> Pat GhcRn
    forall p. XVarPat p -> LIdP p -> Pat p
    VarPat NoExtField
    XVarPat GhcRn
    noExtField (SrcSpanAnnN -> Name -> LocatedN Name
    forall l e. l -> e -> GenLocated l e
    L SrcSpanAnnN
    loc Name
    n))
                                | L SrcSpanAnnN
    loc Name
    n <- [LocatedN Name]
    [LIdP GhcRn]
    args]
                builder_match :: LMatch GhcRn (LHsExpr GhcRn)
    builder_match = HsMatchContext (NoGhcTc GhcRn)
    -> [LPat GhcRn]
    -> LHsExpr GhcRn
    -> HsLocalBinds GhcRn
    -> LMatch GhcRn (LHsExpr GhcRn)
    forall (p :: Pass).
    IsPass p =>
    HsMatchContext (NoGhcTc (GhcPass p))
    -> [LPat (GhcPass p)]
    -> LHsExpr (GhcPass p)
    -> HsLocalBinds (GhcPass p)
    -> LMatch (GhcPass p) (LHsExpr (GhcPass p))
    mkMatch (LIdP (GhcPass (NoGhcTcPass 'Renamed))
    -> HsMatchContext (GhcPass (NoGhcTcPass 'Renamed))
    forall p. LIdP p -> HsMatchContext p
    mkPrefixFunRhs LIdP (GhcPass (NoGhcTcPass 'Renamed))
    LIdP GhcRn
    ps_lname)
                                        [GenLocated SrcSpanAnnA (Pat GhcRn)]
    [LPat GhcRn]
    builder_args LHsExpr GhcRn
    body
                                        (XEmptyLocalBinds GhcRn GhcRn -> HsLocalBinds GhcRn
    forall idL idR. XEmptyLocalBinds idL idR -> HsLocalBindsLR idL idR
    EmptyLocalBinds NoExtField
    XEmptyLocalBinds GhcRn GhcRn
    noExtField)

        args :: [LIdP GhcRn]
    args = case HsPatSynDetails GhcRn
    details of
                  PrefixCon [Void]
    _ [LIdP GhcRn]
    args   -> [LIdP GhcRn]
    args
                  InfixCon LIdP GhcRn
    arg1 LIdP GhcRn
    arg2 -> [LIdP GhcRn
    arg1, LIdP GhcRn
    arg2]
                  RecCon [RecordPatSynField GhcRn]
    args        -> (RecordPatSynField GhcRn -> LocatedN Name)
    -> [RecordPatSynField GhcRn] -> [LocatedN Name]
    forall a b. (a -> b) -> [a] -> [b]
    map RecordPatSynField GhcRn -> LocatedN Name
    forall pass. RecordPatSynField pass -> LIdP pass
    recordPatSynPatVar [RecordPatSynField GhcRn]
    args

        add_dummy_arg :: MatchGroup GhcRn (LHsExpr GhcRn)
                      -> MatchGroup GhcRn (LHsExpr GhcRn)
        add_dummy_arg :: MatchGroup GhcRn (LHsExpr GhcRn)
    -> MatchGroup GhcRn (LHsExpr GhcRn)
    add_dummy_arg mg :: MatchGroup GhcRn (LHsExpr GhcRn)
    mg@(MG { mg_alts :: forall p body. MatchGroup p body -> XRec p [LMatch p body]
    mg_alts =
                               (L SrcSpanAnnL
    l [L SrcSpanAnnA
    loc match :: Match GhcRn (GenLocated SrcSpanAnnA (HsExpr GhcRn))
    match@(Match { m_pats :: forall p body. Match p body -> [LPat p]
    m_pats = [LPat GhcRn]
    pats })]) })
          = MatchGroup GhcRn (GenLocated SrcSpanAnnA (HsExpr GhcRn))
    MatchGroup GhcRn (LHsExpr GhcRn)
    mg { mg_alts :: XRec GhcRn [LMatch GhcRn (GenLocated SrcSpanAnnA (HsExpr GhcRn))]
    mg_alts = SrcSpanAnnL
    -> [LocatedA (Match GhcRn (GenLocated SrcSpanAnnA (HsExpr GhcRn)))]
    -> LocatedL
         [LocatedA (Match GhcRn (GenLocated SrcSpanAnnA (HsExpr GhcRn)))]
    forall l e. l -> e -> GenLocated l e
    L SrcSpanAnnL
    l [SrcSpanAnnA
    -> Match GhcRn (GenLocated SrcSpanAnnA (HsExpr GhcRn))
    -> LocatedA (Match GhcRn (GenLocated SrcSpanAnnA (HsExpr GhcRn)))
    forall l e. l -> e -> GenLocated l e
    L SrcSpanAnnA
    loc (Match GhcRn (GenLocated SrcSpanAnnA (HsExpr GhcRn))
    match { m_pats :: [LPat GhcRn]
    m_pats = GenLocated SrcSpanAnnA (Pat GhcRn)
    LPat GhcRn
    nlWildPatName GenLocated SrcSpanAnnA (Pat GhcRn)
    -> [GenLocated SrcSpanAnnA (Pat GhcRn)]
    -> [GenLocated SrcSpanAnnA (Pat GhcRn)]
    forall a. a -> [a] -> [a]
    : [GenLocated SrcSpanAnnA (Pat GhcRn)]
    [LPat GhcRn]
    pats })] }
        add_dummy_arg MatchGroup GhcRn (LHsExpr GhcRn)
    other_mg = String -> SDoc -> MatchGroup GhcRn (LHsExpr GhcRn)
    forall a. HasCallStack => String -> SDoc -> a
    pprPanic String
    "add_dummy_arg" (SDoc -> MatchGroup GhcRn (LHsExpr GhcRn))
    -> SDoc -> MatchGroup GhcRn (LHsExpr GhcRn)
    forall a b. (a -> b) -> a -> b
    $
                                 MatchGroup GhcRn (GenLocated SrcSpanAnnA (HsExpr GhcRn)) -> SDoc
    forall (idR :: Pass) body.
    (OutputableBndrId idR, Outputable body) =>
    MatchGroup (GhcPass idR) body -> SDoc
    pprMatches MatchGroup GhcRn (GenLocated SrcSpanAnnA (HsExpr GhcRn))
    MatchGroup GhcRn (LHsExpr GhcRn)
    other_mg

    patSynBuilderOcc :: PatSyn -> Maybe (HsExpr GhcTc, TcSigmaType)
    patSynBuilderOcc :: PatSyn -> Maybe (HsExpr GhcTc, Kind)
    patSynBuilderOcc PatSyn
    ps
      | Just (Name
    _, Kind
    builder_ty, Bool
    add_void_arg) <- PatSyn -> PatSynBuilder
    patSynBuilder PatSyn
    ps
      , let builder_expr :: HsExpr GhcTc
    builder_expr = XConLikeOut GhcTc -> ConLike -> HsExpr GhcTc
    forall p. XConLikeOut p -> ConLike -> HsExpr p
    HsConLikeOut NoExtField
    XConLikeOut GhcTc
    noExtField (PatSyn -> ConLike
    PatSynCon PatSyn
    ps)
      = (HsExpr GhcTc, Kind) -> Maybe (HsExpr GhcTc, Kind)
    forall a. a -> Maybe a
    Just ((HsExpr GhcTc, Kind) -> Maybe (HsExpr GhcTc, Kind))
    -> (HsExpr GhcTc, Kind) -> Maybe (HsExpr GhcTc, Kind)
    forall a b. (a -> b) -> a -> b
    $
        if Bool
    add_void_arg
        then ( HsExpr GhcTc
    builder_expr   -- still just return builder_expr; the void# arg
                              -- is added by dsConLike in the desugarer
             , Kind -> Kind
    tcFunResultTy Kind
    builder_ty )
        else (HsExpr GhcTc
    builder_expr, Kind
    builder_ty)

      | Bool
    otherwise  -- Unidirectional
      = Maybe (HsExpr GhcTc, Kind)
    forall a. Maybe a
    Nothing

    add_void :: Bool -> Type -> Type
    add_void :: Bool -> Kind -> Kind
    add_void Bool
    need_dummy_arg Kind
    ty
      | Bool
    need_dummy_arg = Kind -> Kind -> Kind
    mkVisFunTyMany Kind
    unboxedUnitTy Kind
    ty
      | Bool
    otherwise      = Kind
    ty

    tcPatToExpr :: Name -> [LocatedN Name] -> LPat GhcRn
                -> Either SDoc (LHsExpr GhcRn)
    -- Given a /pattern/, return an /expression/ that builds a value
    -- that matches the pattern.  E.g. if the pattern is (Just [x]),
    -- the expression is (Just [x]).  They look the same, but the
    -- input uses constructors from HsPat and the output uses constructors
    -- from HsExpr.
    --
    -- Returns (Left r) if the pattern is not invertible, for reason r.
    -- See Note [Builder for a bidirectional pattern synonym]
    tcPatToExpr :: Name
    -> [LocatedN Name] -> LPat GhcRn -> Either SDoc (LHsExpr GhcRn)
    tcPatToExpr Name
    name [LocatedN Name]
    args LPat GhcRn
    pat = LPat GhcRn -> Either SDoc (LHsExpr GhcRn)
    go LPat GhcRn
    pat
      where
        lhsVars :: NameSet
    lhsVars = [Name] -> NameSet
    mkNameSet ((LocatedN Name -> Name) -> [LocatedN Name] -> [Name]
    forall a b. (a -> b) -> [a] -> [b]
    map LocatedN Name -> Name
    forall l e. GenLocated l e -> e
    unLoc [LocatedN Name]
    args)

        -- Make a prefix con for prefix and infix patterns for simplicity
        mkPrefixConExpr :: LocatedN Name -> [LPat GhcRn]
                        -> Either SDoc (HsExpr GhcRn)
        mkPrefixConExpr :: LocatedN Name -> [LPat GhcRn] -> Either SDoc (HsExpr GhcRn)
    mkPrefixConExpr lcon :: LocatedN Name
    lcon@(L SrcSpanAnnN
    loc Name
    _) [LPat GhcRn]
    pats
          = do { [GenLocated SrcSpanAnnA (HsExpr GhcRn)]
    exprs <- (GenLocated SrcSpanAnnA (Pat GhcRn)
     -> Either SDoc (GenLocated SrcSpanAnnA (HsExpr GhcRn)))
    -> [GenLocated SrcSpanAnnA (Pat GhcRn)]
    -> Either SDoc [GenLocated SrcSpanAnnA (HsExpr GhcRn)]
    forall (t :: * -> *) (m :: * -> *) a b.
    (Traversable t, Monad m) =>
    (a -> m b) -> t a -> m (t b)
    mapM GenLocated SrcSpanAnnA (Pat GhcRn)
    -> Either SDoc (GenLocated SrcSpanAnnA (HsExpr GhcRn))
    LPat GhcRn -> Either SDoc (LHsExpr GhcRn)
    go [GenLocated SrcSpanAnnA (Pat GhcRn)]
    [LPat GhcRn]
    pats
               ; let con :: GenLocated SrcSpanAnnA (HsExpr GhcRn)
    con = SrcSpanAnnA
    -> HsExpr GhcRn -> GenLocated SrcSpanAnnA (HsExpr GhcRn)
    forall l e. l -> e -> GenLocated l e
    L (SrcSpanAnnN -> SrcSpanAnnA
    forall a ann. SrcSpanAnn' a -> SrcAnn ann
    l2l SrcSpanAnnN
    loc) (XVar GhcRn -> LIdP GhcRn -> HsExpr GhcRn
    forall p. XVar p -> LIdP p -> HsExpr p
    HsVar NoExtField
    XVar GhcRn
    noExtField LocatedN Name
    LIdP GhcRn
    lcon)
               ; HsExpr GhcRn -> Either SDoc (HsExpr GhcRn)
    forall (m :: * -> *) a. Monad m => a -> m a
    return (GenLocated SrcSpanAnnA (HsExpr GhcRn) -> HsExpr GhcRn
    forall l e. GenLocated l e -> e
    unLoc (GenLocated SrcSpanAnnA (HsExpr GhcRn) -> HsExpr GhcRn)
    -> GenLocated SrcSpanAnnA (HsExpr GhcRn) -> HsExpr GhcRn
    forall a b. (a -> b) -> a -> b
    $ LHsExpr GhcRn -> [LHsExpr GhcRn] -> LHsExpr GhcRn
    forall (id :: Pass).
    LHsExpr (GhcPass id)
    -> [LHsExpr (GhcPass id)] -> LHsExpr (GhcPass id)
    mkHsApps GenLocated SrcSpanAnnA (HsExpr GhcRn)
    LHsExpr GhcRn
    con [GenLocated SrcSpanAnnA (HsExpr GhcRn)]
    [LHsExpr GhcRn]
    exprs)
               }

        mkRecordConExpr :: LocatedN Name -> HsRecFields GhcRn (LPat GhcRn)
                        -> Either SDoc (HsExpr GhcRn)
        mkRecordConExpr :: LocatedN Name
    -> HsRecFields GhcRn (LPat GhcRn) -> Either SDoc (HsExpr GhcRn)
    mkRecordConExpr LocatedN Name
    con (HsRecFields [LHsRecField GhcRn (LPat GhcRn)]
    fields Maybe (Located Int)
    dd)
          = do { [GenLocated
       SrcSpanAnnA
       (HsRecField'
          (FieldOcc GhcRn) (GenLocated SrcSpanAnnA (HsExpr GhcRn)))]
    exprFields <- (GenLocated
       SrcSpanAnnA
       (HsRecField' (FieldOcc GhcRn) (GenLocated SrcSpanAnnA (Pat GhcRn)))
     -> Either
          SDoc
          (GenLocated
             SrcSpanAnnA
             (HsRecField'
                (FieldOcc GhcRn) (GenLocated SrcSpanAnnA (HsExpr GhcRn)))))
    -> [GenLocated
          SrcSpanAnnA
          (HsRecField'
             (FieldOcc GhcRn) (GenLocated SrcSpanAnnA (Pat GhcRn)))]
    -> Either
         SDoc
         [GenLocated
            SrcSpanAnnA
            (HsRecField'
               (FieldOcc GhcRn) (GenLocated SrcSpanAnnA (HsExpr GhcRn)))]
    forall (t :: * -> *) (m :: * -> *) a b.
    (Traversable t, Monad m) =>
    (a -> m b) -> t a -> m (t b)
    mapM GenLocated
      SrcSpanAnnA
      (HsRecField' (FieldOcc GhcRn) (GenLocated SrcSpanAnnA (Pat GhcRn)))
    -> Either
         SDoc
         (GenLocated
            SrcSpanAnnA
            (HsRecField'
               (FieldOcc GhcRn) (GenLocated SrcSpanAnnA (HsExpr GhcRn))))
    LHsRecField GhcRn (LPat GhcRn)
    -> Either SDoc (LHsRecField GhcRn (LHsExpr GhcRn))
    go' [GenLocated
       SrcSpanAnnA
       (HsRecField'
          (FieldOcc GhcRn) (GenLocated SrcSpanAnnA (Pat GhcRn)))]
    [LHsRecField GhcRn (LPat GhcRn)]
    fields
               ; HsExpr GhcRn -> Either SDoc (HsExpr GhcRn)
    forall (m :: * -> *) a. Monad m => a -> m a
    return (XRecordCon GhcRn
    -> XRec GhcRn (ConLikeP GhcRn)
    -> HsRecordBinds GhcRn
    -> HsExpr GhcRn
    forall p.
    XRecordCon p -> XRec p (ConLikeP p) -> HsRecordBinds p -> HsExpr p
    RecordCon NoExtField
    XRecordCon GhcRn
    noExtField LocatedN Name
    XRec GhcRn (ConLikeP GhcRn)
    con ([LHsRecField GhcRn (GenLocated SrcSpanAnnA (HsExpr GhcRn))]
    -> Maybe (Located Int)
    -> HsRecFields GhcRn (GenLocated SrcSpanAnnA (HsExpr GhcRn))
    forall p arg.
    [LHsRecField p arg] -> Maybe (Located Int) -> HsRecFields p arg
    HsRecFields [GenLocated
       SrcSpanAnnA
       (HsRecField'
          (FieldOcc GhcRn) (GenLocated SrcSpanAnnA (HsExpr GhcRn)))]
    [LHsRecField GhcRn (GenLocated SrcSpanAnnA (HsExpr GhcRn))]
    exprFields Maybe (Located Int)
    dd)) }

        go' :: LHsRecField GhcRn (LPat GhcRn) -> Either SDoc (LHsRecField GhcRn (LHsExpr GhcRn))
        go' :: LHsRecField GhcRn (LPat GhcRn)
    -> Either SDoc (LHsRecField GhcRn (LHsExpr GhcRn))
    go' (L SrcSpanAnnA
    l HsRecField' (FieldOcc GhcRn) (GenLocated SrcSpanAnnA (Pat GhcRn))
    rf) = SrcSpanAnnA
    -> HsRecField'
         (FieldOcc GhcRn) (GenLocated SrcSpanAnnA (HsExpr GhcRn))
    -> GenLocated
         SrcSpanAnnA
         (HsRecField'
            (FieldOcc GhcRn) (GenLocated SrcSpanAnnA (HsExpr GhcRn)))
    forall l e. l -> e -> GenLocated l e
    L SrcSpanAnnA
    l (HsRecField'
       (FieldOcc GhcRn) (GenLocated SrcSpanAnnA (HsExpr GhcRn))
     -> GenLocated
          SrcSpanAnnA
          (HsRecField'
             (FieldOcc GhcRn) (GenLocated SrcSpanAnnA (HsExpr GhcRn))))
    -> Either
         SDoc
         (HsRecField'
            (FieldOcc GhcRn) (GenLocated SrcSpanAnnA (HsExpr GhcRn)))
    -> Either
         SDoc
         (GenLocated
            SrcSpanAnnA
            (HsRecField'
               (FieldOcc GhcRn) (GenLocated SrcSpanAnnA (HsExpr GhcRn))))
    forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
    <$> (GenLocated SrcSpanAnnA (Pat GhcRn)
     -> Either SDoc (GenLocated SrcSpanAnnA (HsExpr GhcRn)))
    -> HsRecField'
         (FieldOcc GhcRn) (GenLocated SrcSpanAnnA (Pat GhcRn))
    -> Either
         SDoc
         (HsRecField'
            (FieldOcc GhcRn) (GenLocated SrcSpanAnnA (HsExpr GhcRn)))
    forall (t :: * -> *) (f :: * -> *) a b.
    (Traversable t, Applicative f) =>
    (a -> f b) -> t a -> f (t b)
    traverse GenLocated SrcSpanAnnA (Pat GhcRn)
    -> Either SDoc (GenLocated SrcSpanAnnA (HsExpr GhcRn))
    LPat GhcRn -> Either SDoc (LHsExpr GhcRn)
    go HsRecField' (FieldOcc GhcRn) (GenLocated SrcSpanAnnA (Pat GhcRn))
    rf

        go :: LPat GhcRn -> Either SDoc (LHsExpr GhcRn)
        go :: LPat GhcRn -> Either SDoc (LHsExpr GhcRn)
    go (L SrcSpanAnnA
    loc Pat GhcRn
    p) = SrcSpanAnnA
    -> HsExpr GhcRn -> GenLocated SrcSpanAnnA (HsExpr GhcRn)
    forall l e. l -> e -> GenLocated l e
    L SrcSpanAnnA
    loc (HsExpr GhcRn -> GenLocated SrcSpanAnnA (HsExpr GhcRn))
    -> Either SDoc (HsExpr GhcRn)
    -> Either SDoc (GenLocated SrcSpanAnnA (HsExpr GhcRn))
    forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
    <$> Pat GhcRn -> Either SDoc (HsExpr GhcRn)
    go1 Pat GhcRn
    p

        go1 :: Pat GhcRn -> Either SDoc (HsExpr GhcRn)
        go1 :: Pat GhcRn -> Either SDoc (HsExpr GhcRn)
    go1 (ConPat NoExtField
    XConPat GhcRn
    NoExtField XRec GhcRn (ConLikeP GhcRn)
    con HsConPatDetails GhcRn
    info)
          = case HsConPatDetails GhcRn
    info of
              PrefixCon [HsPatSigType (NoGhcTc GhcRn)]
    _ [LPat GhcRn]
    ps -> LocatedN Name -> [LPat GhcRn] -> Either SDoc (HsExpr GhcRn)
    mkPrefixConExpr LocatedN Name
    XRec GhcRn (ConLikeP GhcRn)
    con [LPat GhcRn]
    ps
              InfixCon LPat GhcRn
    l LPat GhcRn
    r   -> LocatedN Name -> [LPat GhcRn] -> Either SDoc (HsExpr GhcRn)
    mkPrefixConExpr LocatedN Name
    XRec GhcRn (ConLikeP GhcRn)
    con [LPat GhcRn
    l,LPat GhcRn
    r]
              RecCon HsRecFields GhcRn (LPat GhcRn)
    fields  -> LocatedN Name
    -> HsRecFields GhcRn (LPat GhcRn) -> Either SDoc (HsExpr GhcRn)
    mkRecordConExpr LocatedN Name
    XRec GhcRn (ConLikeP GhcRn)
    con HsRecFields GhcRn (LPat GhcRn)
    fields

        go1 (SigPat XSigPat GhcRn
    _ LPat GhcRn
    pat HsPatSigType (NoGhcTc GhcRn)
    _) = Pat GhcRn -> Either SDoc (HsExpr GhcRn)
    go1 (GenLocated SrcSpanAnnA (Pat GhcRn) -> Pat GhcRn
    forall l e. GenLocated l e -> e
    unLoc GenLocated SrcSpanAnnA (Pat GhcRn)
    LPat GhcRn
    pat)
            -- See Note [Type signatures and the builder expression]

        go1 (VarPat XVarPat GhcRn
    _ (L SrcSpanAnnN
    l Name
    var))
            | Name
    var Name -> NameSet -> Bool
    `elemNameSet` NameSet
    lhsVars
            = HsExpr GhcRn -> Either SDoc (HsExpr GhcRn)
    forall (m :: * -> *) a. Monad m => a -> m a
    return (HsExpr GhcRn -> Either SDoc (HsExpr GhcRn))
    -> HsExpr GhcRn -> Either SDoc (HsExpr GhcRn)
    forall a b. (a -> b) -> a -> b
    $ XVar GhcRn -> LIdP GhcRn -> HsExpr GhcRn
    forall p. XVar p -> LIdP p -> HsExpr p
    HsVar NoExtField
    XVar GhcRn
    noExtField (SrcSpanAnnN -> Name -> LocatedN Name
    forall l e. l -> e -> GenLocated l e
    L SrcSpanAnnN
    l Name
    var)
            | Bool
    otherwise
            = SDoc -> Either SDoc (HsExpr GhcRn)
    forall a b. a -> Either a b
    Left (SDoc -> SDoc
    quotes (Name -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr Name
    var) SDoc -> SDoc -> SDoc
    <+> String -> SDoc
    text String
    "is not bound by the LHS of the pattern synonym")
        go1 (ParPat XParPat GhcRn
    _ LPat GhcRn
    pat)          = (LHsExpr GhcRn -> HsExpr GhcRn)
    -> Either SDoc (LHsExpr GhcRn) -> Either SDoc (HsExpr GhcRn)
    forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
    fmap (XPar GhcRn -> LHsExpr GhcRn -> HsExpr GhcRn
    forall p. XPar p -> LHsExpr p -> HsExpr p
    HsPar XPar GhcRn
    forall a. EpAnn a
    noAnn) (Either SDoc (LHsExpr GhcRn) -> Either SDoc (HsExpr GhcRn))
    -> Either SDoc (LHsExpr GhcRn) -> Either SDoc (HsExpr GhcRn)
    forall a b. (a -> b) -> a -> b
    $ LPat GhcRn -> Either SDoc (LHsExpr GhcRn)
    go LPat GhcRn
    pat
        go1 p :: Pat GhcRn
    p@(ListPat XListPat GhcRn
    reb [LPat GhcRn]
    pats)
          | Maybe SyntaxExprRn
    XListPat GhcRn
    Nothing <- XListPat GhcRn
    reb = do { [GenLocated SrcSpanAnnA (HsExpr GhcRn)]
    exprs <- (GenLocated SrcSpanAnnA (Pat GhcRn)
     -> Either SDoc (GenLocated SrcSpanAnnA (HsExpr GhcRn)))
    -> [GenLocated SrcSpanAnnA (Pat GhcRn)]
    -> Either SDoc [GenLocated SrcSpanAnnA (HsExpr GhcRn)]
    forall (t :: * -> *) (m :: * -> *) a b.
    (Traversable t, Monad m) =>
    (a -> m b) -> t a -> m (t b)
    mapM GenLocated SrcSpanAnnA (Pat GhcRn)
    -> Either SDoc (GenLocated SrcSpanAnnA (HsExpr GhcRn))
    LPat GhcRn -> Either SDoc (LHsExpr GhcRn)
    go [GenLocated SrcSpanAnnA (Pat GhcRn)]
    [LPat GhcRn]
    pats
                                ; HsExpr GhcRn -> Either SDoc (HsExpr GhcRn)
    forall (m :: * -> *) a. Monad m => a -> m a
    return (HsExpr GhcRn -> Either SDoc (HsExpr GhcRn))
    -> HsExpr GhcRn -> Either SDoc (HsExpr GhcRn)
    forall a b. (a -> b) -> a -> b
    $ XExplicitList GhcRn -> [LHsExpr GhcRn] -> HsExpr GhcRn
    forall p. XExplicitList p -> [LHsExpr p] -> HsExpr p
    ExplicitList NoExtField
    XExplicitList GhcRn
    noExtField [GenLocated SrcSpanAnnA (HsExpr GhcRn)]
    [LHsExpr GhcRn]
    exprs }
          | Bool
    otherwise                   = Pat GhcRn -> Either SDoc (HsExpr GhcRn)
    notInvertibleListPat Pat GhcRn
    p
        go1 (TuplePat XTuplePat GhcRn
    _ [LPat GhcRn]
    pats Boxity
    box)       = do { [GenLocated SrcSpanAnnA (HsExpr GhcRn)]
    exprs <- (GenLocated SrcSpanAnnA (Pat GhcRn)
     -> Either SDoc (GenLocated SrcSpanAnnA (HsExpr GhcRn)))
    -> [GenLocated SrcSpanAnnA (Pat GhcRn)]
    -> Either SDoc [GenLocated SrcSpanAnnA (HsExpr GhcRn)]
    forall (t :: * -> *) (m :: * -> *) a b.
    (Traversable t, Monad m) =>
    (a -> m b) -> t a -> m (t b)
    mapM GenLocated SrcSpanAnnA (Pat GhcRn)
    -> Either SDoc (GenLocated SrcSpanAnnA (HsExpr GhcRn))
    LPat GhcRn -> Either SDoc (LHsExpr GhcRn)
    go [GenLocated SrcSpanAnnA (Pat GhcRn)]
    [LPat GhcRn]
    pats
                                             ; HsExpr GhcRn -> Either SDoc (HsExpr GhcRn)
    forall (m :: * -> *) a. Monad m => a -> m a
    return (HsExpr GhcRn -> Either SDoc (HsExpr GhcRn))
    -> HsExpr GhcRn -> Either SDoc (HsExpr GhcRn)
    forall a b. (a -> b) -> a -> b
    $ XExplicitTuple GhcRn -> [HsTupArg GhcRn] -> Boxity -> HsExpr GhcRn
    forall p. XExplicitTuple p -> [HsTupArg p] -> Boxity -> HsExpr p
    ExplicitTuple NoExtField
    XExplicitTuple GhcRn
    noExtField
                                               ((GenLocated SrcSpanAnnA (HsExpr GhcRn) -> HsTupArg GhcRn)
    -> [GenLocated SrcSpanAnnA (HsExpr GhcRn)] -> [HsTupArg GhcRn]
    forall a b. (a -> b) -> [a] -> [b]
    map (XPresent GhcRn -> LHsExpr GhcRn -> HsTupArg GhcRn
    forall id. XPresent id -> LHsExpr id -> HsTupArg id
    Present XPresent GhcRn
    forall a. EpAnn a
    noAnn) [GenLocated SrcSpanAnnA (HsExpr GhcRn)]
    exprs) Boxity
    box }
        go1 (SumPat XSumPat GhcRn
    _ LPat GhcRn
    pat Int
    alt Int
    arity)    = do { HsExpr GhcRn
    expr <- Pat GhcRn -> Either SDoc (HsExpr GhcRn)
    go1 (GenLocated SrcSpanAnnA (Pat GhcRn) -> Pat GhcRn
    forall l e. GenLocated l e -> e
    unLoc GenLocated SrcSpanAnnA (Pat GhcRn)
    LPat GhcRn
    pat)
                                             ; HsExpr GhcRn -> Either SDoc (HsExpr GhcRn)
    forall (m :: * -> *) a. Monad m => a -> m a
    return (HsExpr GhcRn -> Either SDoc (HsExpr GhcRn))
    -> HsExpr GhcRn -> Either SDoc (HsExpr GhcRn)
    forall a b. (a -> b) -> a -> b
    $ XExplicitSum GhcRn -> Int -> Int -> LHsExpr GhcRn -> HsExpr GhcRn
    forall p. XExplicitSum p -> Int -> Int -> LHsExpr p -> HsExpr p
    ExplicitSum NoExtField
    XExplicitSum GhcRn
    noExtField Int
    alt Int
    arity
                                                                       (HsExpr GhcRn -> GenLocated SrcSpanAnnA (HsExpr GhcRn)
    forall a an. a -> LocatedAn an a
    noLocA HsExpr GhcRn
    expr)
                                             }
        go1 (LitPat XLitPat GhcRn
    _ HsLit GhcRn
    lit)              = HsExpr GhcRn -> Either SDoc (HsExpr GhcRn)
    forall (m :: * -> *) a. Monad m => a -> m a
    return (HsExpr GhcRn -> Either SDoc (HsExpr GhcRn))
    -> HsExpr GhcRn -> Either SDoc (HsExpr GhcRn)
    forall a b. (a -> b) -> a -> b
    $ XLitE GhcRn -> HsLit GhcRn -> HsExpr GhcRn
    forall p. XLitE p -> HsLit p -> HsExpr p
    HsLit EpAnnCO
    XLitE GhcRn
    noComments HsLit GhcRn
    lit
        go1 (NPat XNPat GhcRn
    _ (L SrcSpan
    _ HsOverLit GhcRn
    n) Maybe (SyntaxExpr GhcRn)
    mb_neg SyntaxExpr GhcRn
    _)
            | Just (SyntaxExprRn HsExpr GhcRn
    neg) <- Maybe (SyntaxExpr GhcRn)
    mb_neg
                                        = HsExpr GhcRn -> Either SDoc (HsExpr GhcRn)
    forall (m :: * -> *) a. Monad m => a -> m a
    return (HsExpr GhcRn -> Either SDoc (HsExpr GhcRn))
    -> HsExpr GhcRn -> Either SDoc (HsExpr GhcRn)
    forall a b. (a -> b) -> a -> b
    $ GenLocated SrcSpanAnnA (HsExpr GhcRn) -> HsExpr GhcRn
    forall l e. GenLocated l e -> e
    unLoc (GenLocated SrcSpanAnnA (HsExpr GhcRn) -> HsExpr GhcRn)
    -> GenLocated SrcSpanAnnA (HsExpr GhcRn) -> HsExpr GhcRn
    forall a b. (a -> b) -> a -> b
    $ (GenLocated SrcSpanAnnA (HsExpr GhcRn)
     -> GenLocated SrcSpanAnnA (HsExpr GhcRn)
     -> GenLocated SrcSpanAnnA (HsExpr GhcRn))
    -> GenLocated SrcSpanAnnA (HsExpr GhcRn)
    -> [GenLocated SrcSpanAnnA (HsExpr GhcRn)]
    -> GenLocated SrcSpanAnnA (HsExpr GhcRn)
    forall (t :: * -> *) b a.
    Foldable t =>
    (b -> a -> b) -> b -> t a -> b
    foldl' GenLocated SrcSpanAnnA (HsExpr GhcRn)
    -> GenLocated SrcSpanAnnA (HsExpr GhcRn)
    -> GenLocated SrcSpanAnnA (HsExpr GhcRn)
    forall (id :: Pass).
    IsPass id =>
    LHsExpr (GhcPass id)
    -> LHsExpr (GhcPass id) -> LHsExpr (GhcPass id)
    nlHsApp (HsExpr GhcRn -> GenLocated SrcSpanAnnA (HsExpr GhcRn)
    forall a an. a -> LocatedAn an a
    noLocA HsExpr GhcRn
    neg)
                                                           [HsExpr GhcRn -> GenLocated SrcSpanAnnA (HsExpr GhcRn)
    forall a an. a -> LocatedAn an a
    noLocA (XOverLitE GhcRn -> HsOverLit GhcRn -> HsExpr GhcRn
    forall p. XOverLitE p -> HsOverLit p -> HsExpr p
    HsOverLit XOverLitE GhcRn
    forall a. EpAnn a
    noAnn HsOverLit GhcRn
    n)]
            | Bool
    otherwise                 = HsExpr GhcRn -> Either SDoc (HsExpr GhcRn)
    forall (m :: * -> *) a. Monad m => a -> m a
    return (HsExpr GhcRn -> Either SDoc (HsExpr GhcRn))
    -> HsExpr GhcRn -> Either SDoc (HsExpr GhcRn)
    forall a b. (a -> b) -> a -> b
    $ XOverLitE GhcRn -> HsOverLit GhcRn -> HsExpr GhcRn
    forall p. XOverLitE p -> HsOverLit p -> HsExpr p
    HsOverLit XOverLitE GhcRn
    forall a. EpAnn a
    noAnn HsOverLit GhcRn
    n
        go1 (SplicePat XSplicePat GhcRn
    _ (HsSpliced XSpliced GhcRn
    _ ThModFinalizers
    _ (HsSplicedPat Pat GhcRn
    pat)))
                                        = Pat GhcRn -> Either SDoc (HsExpr GhcRn)
    go1 Pat GhcRn
    pat
        go1 (SplicePat XSplicePat GhcRn
    _ (HsSpliced{})) = String -> Either SDoc (HsExpr GhcRn)
    forall a. String -> a
    panic String
    "Invalid splice variety"

        -- The following patterns are not invertible.
        go1 p :: Pat GhcRn
    p@(BangPat {})                       = Pat GhcRn -> Either SDoc (HsExpr GhcRn)
    notInvertible Pat GhcRn
    p -- #14112
        go1 p :: Pat GhcRn
    p@(LazyPat {})                       = Pat GhcRn -> Either SDoc (HsExpr GhcRn)
    notInvertible Pat GhcRn
    p
        go1 p :: Pat GhcRn
    p@(WildPat {})                       = Pat GhcRn -> Either SDoc (HsExpr GhcRn)
    notInvertible Pat GhcRn
    p
        go1 p :: Pat GhcRn
    p@(AsPat {})                         = Pat GhcRn -> Either SDoc (HsExpr GhcRn)
    notInvertible Pat GhcRn
    p
        go1 p :: Pat GhcRn
    p@(ViewPat {})                       = Pat GhcRn -> Either SDoc (HsExpr GhcRn)
    notInvertible Pat GhcRn
    p
        go1 p :: Pat GhcRn
    p@(NPlusKPat {})                     = Pat GhcRn -> Either SDoc (HsExpr GhcRn)
    notInvertible Pat GhcRn
    p
        go1 p :: Pat GhcRn
    p@(SplicePat XSplicePat GhcRn
    _ (HsTypedSplice {}))   = Pat GhcRn -> Either SDoc (HsExpr GhcRn)
    notInvertible Pat GhcRn
    p
        go1 p :: Pat GhcRn
    p@(SplicePat XSplicePat GhcRn
    _ (HsUntypedSplice {})) = Pat GhcRn -> Either SDoc (HsExpr GhcRn)
    notInvertible Pat GhcRn
    p
        go1 p :: Pat GhcRn
    p@(SplicePat XSplicePat GhcRn
    _ (HsQuasiQuote {}))    = Pat GhcRn -> Either SDoc (HsExpr GhcRn)
    notInvertible Pat GhcRn
    p

        notInvertible :: Pat GhcRn -> Either SDoc (HsExpr GhcRn)
    notInvertible Pat GhcRn
    p = SDoc -> Either SDoc (HsExpr GhcRn)
    forall a b. a -> Either a b
    Left (Pat GhcRn -> SDoc
    not_invertible_msg Pat GhcRn
    p)

        not_invertible_msg :: Pat GhcRn -> SDoc
    not_invertible_msg Pat GhcRn
    p
          =   String -> SDoc
    text String
    "Pattern" SDoc -> SDoc -> SDoc
    <+> SDoc -> SDoc
    quotes (Pat GhcRn -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr Pat GhcRn
    p) SDoc -> SDoc -> SDoc
    <+> String -> SDoc
    text String
    "is not invertible"
          SDoc -> SDoc -> SDoc
    $+$ SDoc -> Int -> SDoc -> SDoc
    hang (String -> SDoc
    text String
    "Suggestion: instead use an explicitly bidirectional"
                    SDoc -> SDoc -> SDoc
    <+> String -> SDoc
    text String
    "pattern synonym, e.g.")
                 Int
    2 (SDoc -> Int -> SDoc -> SDoc
    hang (String -> SDoc
    text String
    "pattern" SDoc -> SDoc -> SDoc
    <+> SDoc
    pp_name SDoc -> SDoc -> SDoc
    <+> SDoc
    pp_args SDoc -> SDoc -> SDoc
    <+> SDoc
    larrow
                          SDoc -> SDoc -> SDoc
    <+> GenLocated SrcSpanAnnA (Pat GhcRn) -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr GenLocated SrcSpanAnnA (Pat GhcRn)
    LPat GhcRn
    pat SDoc -> SDoc -> SDoc
    <+> String -> SDoc
    text String
    "where")
                       Int
    2 (SDoc
    pp_name SDoc -> SDoc -> SDoc
    <+> SDoc
    pp_args SDoc -> SDoc -> SDoc
    <+> SDoc
    equals SDoc -> SDoc -> SDoc
    <+> String -> SDoc
    text String
    "..."))
          where
            pp_name :: SDoc
    pp_name = Name -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr Name
    name
            pp_args :: SDoc
    pp_args = [SDoc] -> SDoc
    hsep ((LocatedN Name -> SDoc) -> [LocatedN Name] -> [SDoc]
    forall a b. (a -> b) -> [a] -> [b]
    map LocatedN Name -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr [LocatedN Name]
    args)

        -- We should really be able to invert list patterns, even when
        -- rebindable syntax is on, but doing so involves a bit of
        -- refactoring; see #14380.  Until then we reject with a
        -- helpful error message.
        notInvertibleListPat :: Pat GhcRn -> Either SDoc (HsExpr GhcRn)
    notInvertibleListPat Pat GhcRn
    p
          = SDoc -> Either SDoc (HsExpr GhcRn)
    forall a b. a -> Either a b
    Left ([SDoc] -> SDoc
    vcat [ Pat GhcRn -> SDoc
    not_invertible_msg Pat GhcRn
    p
                       , String -> SDoc
    text String
    "Reason: rebindable syntax is on."
                       , String -> SDoc
    text String
    "This is fixable: add use-case to #14380" ])

    {- Note [Builder for a bidirectional pattern synonym]
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    For a bidirectional pattern synonym we need to produce an /expression/
    that matches the supplied /pattern/, given values for the arguments
    of the pattern synonym.  For example
      pattern F x y = (Just x, [y])
    The 'builder' for F looks like
      $builderF x y = (Just x, [y])

    We can't always do this:
     * Some patterns aren't invertible; e.g. view patterns
          pattern F x = (reverse -> x:_)

     * The RHS pattern might bind more variables than the pattern
       synonym, so again we can't invert it
          pattern F x = (x,y)

     * Ditto wildcards
          pattern F x = (x,_)

    Note [Redundant constraints for builder]
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    The builder can have redundant constraints, which are awkward to eliminate.
    Consider
       pattern P = Just 34
    To match against this pattern we need (Eq a, Num a).  But to build
    (Just 34) we need only (Num a).  Fortunately instTcSigFromId sets
    sig_warn_redundant to False.

    ************************************************************************
    *                                                                      *
             Helper functions
    *                                                                      *
    ************************************************************************

    Note [As-patterns in pattern synonym definitions]
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    The rationale for rejecting as-patterns in pattern synonym definitions
    is that an as-pattern would introduce nonindependent pattern synonym
    arguments, e.g. given a pattern synonym like:

            pattern K x y = x@(Just y)

    one could write a nonsensical function like

            f (K Nothing x) = ...

    or
            g (K (Just True) False) = ...

    Note [Type signatures and the builder expression]
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    Consider
       pattern L x = Left x :: Either [a] [b]

    In tc{Infer/Check}PatSynDecl we will check that the pattern has the
    specified type.  We check the pattern *as a pattern*, so the type
    signature is a pattern signature, and so brings 'a' and 'b' into
    scope.  But we don't have a way to bind 'a, b' in the LHS, as we do
    'x', say.  Nevertheless, the signature may be useful to constrain
    the type.

    When making the binding for the *builder*, though, we don't want
      $buildL x = Left x :: Either [a] [b]
    because that wil either mean (forall a b. Either [a] [b]), or we'll
    get a complaint that 'a' and 'b' are out of scope. (Actually the
    latter; #9867.)  No, the job of the signature is done, so when
    converting the pattern to an expression (for the builder RHS) we
    simply discard the signature.

    Note [Record PatSyn Desugaring]
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    It is important that prov_theta comes before req_theta as this ordering is used
    when desugaring record pattern synonym updates.

    Any change to this ordering should make sure to change GHC.HsToCore.Expr if you
    want to avoid difficult to decipher core lint errors!

    Note [Pragmas for pattern synonyms]
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    INLINE and NOINLINE pragmas are supported for pattern synonyms. They affect both
    the matcher and the builder.
    (See Note [Matchers and builders for pattern synonyms] in PatSyn)

    For example:
        pattern InlinedPattern x = [x]
        {-# INLINE InlinedPattern #-}
        pattern NonInlinedPattern x = [x]
        {-# NOINLINE NonInlinedPattern #-}

    For pattern synonyms with explicit builders, only pragma for the entire pattern
    synonym is supported. For example:
        pattern HeadC x <- x:xs where
          HeadC x = [x]
          -- This wouldn't compile: {-# INLINE HeadC #-}
        {-# INLINE HeadC #-} -- But this works

    When no pragma is provided for a pattern, the inlining decision might change
    between different versions of GHC.
     -}

    -- Walk the whole pattern and for all ConPatOuts, collect the
    -- existentially-bound type variables and evidence binding variables.
    --
    -- These are used in computing the type of a pattern synonym and also
    -- in generating matcher functions, since success continuations need
    -- to be passed these pattern-bound evidences.
    tcCollectEx
      :: LPat GhcTc
      -> ( [TyVar]        -- Existentially-bound type variables
                          -- in correctly-scoped order; e.g. [ k:*, x:k ]
         , [EvVar] )      -- and evidence variables

    tcCollectEx :: LPat GhcTc -> ([Id], [Id])
    tcCollectEx LPat GhcTc
    pat = LPat GhcTc -> ([Id], [Id])
    go LPat GhcTc
    pat
      where
        go :: LPat GhcTc -> ([TyVar], [EvVar])
        go :: LPat GhcTc -> ([Id], [Id])
    go = Pat GhcTc -> ([Id], [Id])
    go1 (Pat GhcTc -> ([Id], [Id]))
    -> (GenLocated SrcSpanAnnA (Pat GhcTc) -> Pat GhcTc)
    -> GenLocated SrcSpanAnnA (Pat GhcTc)
    -> ([Id], [Id])
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . GenLocated SrcSpanAnnA (Pat GhcTc) -> Pat GhcTc
    forall l e. GenLocated l e -> e
    unLoc

        go1 :: Pat GhcTc -> ([TyVar], [EvVar])
        go1 :: Pat GhcTc -> ([Id], [Id])
    go1 (LazyPat XLazyPat GhcTc
    _ LPat GhcTc
    p)      = LPat GhcTc -> ([Id], [Id])
    go LPat GhcTc
    p
        go1 (AsPat XAsPat GhcTc
    _ LIdP GhcTc
    _ LPat GhcTc
    p)      = LPat GhcTc -> ([Id], [Id])
    go LPat GhcTc
    p
        go1 (ParPat XParPat GhcTc
    _ LPat GhcTc
    p)       = LPat GhcTc -> ([Id], [Id])
    go LPat GhcTc
    p
        go1 (BangPat XBangPat GhcTc
    _ LPat GhcTc
    p)      = LPat GhcTc -> ([Id], [Id])
    go LPat GhcTc
    p
        go1 (ListPat XListPat GhcTc
    _ [LPat GhcTc]
    ps)     = [([Id], [Id])] -> ([Id], [Id])
    forall {a} {a}. [([a], [a])] -> ([a], [a])
    mergeMany ([([Id], [Id])] -> ([Id], [Id]))
    -> ([LPat GhcTc] -> [([Id], [Id])]) -> [LPat GhcTc] -> ([Id], [Id])
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . (GenLocated SrcSpanAnnA (Pat GhcTc) -> ([Id], [Id]))
    -> [GenLocated SrcSpanAnnA (Pat GhcTc)] -> [([Id], [Id])]
    forall a b. (a -> b) -> [a] -> [b]
    map GenLocated SrcSpanAnnA (Pat GhcTc) -> ([Id], [Id])
    LPat GhcTc -> ([Id], [Id])
    go ([LPat GhcTc] -> ([Id], [Id])) -> [LPat GhcTc] -> ([Id], [Id])
    forall a b. (a -> b) -> a -> b
    $ [LPat GhcTc]
    ps
        go1 (TuplePat XTuplePat GhcTc
    _ [LPat GhcTc]
    ps Boxity
    _)  = [([Id], [Id])] -> ([Id], [Id])
    forall {a} {a}. [([a], [a])] -> ([a], [a])
    mergeMany ([([Id], [Id])] -> ([Id], [Id]))
    -> ([LPat GhcTc] -> [([Id], [Id])]) -> [LPat GhcTc] -> ([Id], [Id])
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . (GenLocated SrcSpanAnnA (Pat GhcTc) -> ([Id], [Id]))
    -> [GenLocated SrcSpanAnnA (Pat GhcTc)] -> [([Id], [Id])]
    forall a b. (a -> b) -> [a] -> [b]
    map GenLocated SrcSpanAnnA (Pat GhcTc) -> ([Id], [Id])
    LPat GhcTc -> ([Id], [Id])
    go ([LPat GhcTc] -> ([Id], [Id])) -> [LPat GhcTc] -> ([Id], [Id])
    forall a b. (a -> b) -> a -> b
    $ [LPat GhcTc]
    ps
        go1 (SumPat XSumPat GhcTc
    _ LPat GhcTc
    p Int
    _ Int
    _)   = LPat GhcTc -> ([Id], [Id])
    go LPat GhcTc
    p
        go1 (ViewPat XViewPat GhcTc
    _ LHsExpr GhcTc
    _ LPat GhcTc
    p)    = LPat GhcTc -> ([Id], [Id])
    go LPat GhcTc
    p
        go1 con :: Pat GhcTc
    con@ConPat{ pat_con_ext :: forall p. Pat p -> XConPat p
    pat_con_ext = XConPat GhcTc
    con' }
                               = ([Id], [Id]) -> ([Id], [Id]) -> ([Id], [Id])
    forall {a} {a}. ([a], [a]) -> ([a], [a]) -> ([a], [a])
    merge (ConPatTc -> [Id]
    cpt_tvs XConPat GhcTc
    ConPatTc
    con', ConPatTc -> [Id]
    cpt_dicts XConPat GhcTc
    ConPatTc
    con') (([Id], [Id]) -> ([Id], [Id])) -> ([Id], [Id]) -> ([Id], [Id])
    forall a b. (a -> b) -> a -> b
    $
                                  HsConPatDetails GhcTc -> ([Id], [Id])
    goConDetails (HsConPatDetails GhcTc -> ([Id], [Id]))
    -> HsConPatDetails GhcTc -> ([Id], [Id])
    forall a b. (a -> b) -> a -> b
    $ Pat GhcTc -> HsConPatDetails GhcTc
    forall p. Pat p -> HsConPatDetails p
    pat_args Pat GhcTc
    con
        go1 (SigPat XSigPat GhcTc
    _ LPat GhcTc
    p HsPatSigType (NoGhcTc GhcTc)
    _)     = LPat GhcTc -> ([Id], [Id])
    go LPat GhcTc
    p
        go1 (XPat (CoPat HsWrapper
    _ Pat GhcTc
    p Kind
    _)) = Pat GhcTc -> ([Id], [Id])
    go1 Pat GhcTc
    p
        go1 (NPlusKPat XNPlusKPat GhcTc
    _ LIdP GhcTc
    n XRec GhcTc (HsOverLit GhcTc)
    k HsOverLit GhcTc
    _ SyntaxExpr GhcTc
    geq SyntaxExpr GhcTc
    subtract)
          = String -> SDoc -> ([Id], [Id])
    forall a. HasCallStack => String -> SDoc -> a
    pprPanic String
    "TODO: NPlusKPat" (SDoc -> ([Id], [Id])) -> SDoc -> ([Id], [Id])
    forall a b. (a -> b) -> a -> b
    $ GenLocated SrcSpanAnnN Id -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr GenLocated SrcSpanAnnN Id
    LIdP GhcTc
    n SDoc -> SDoc -> SDoc
    $$ GenLocated SrcSpan (HsOverLit GhcTc) -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr GenLocated SrcSpan (HsOverLit GhcTc)
    XRec GhcTc (HsOverLit GhcTc)
    k SDoc -> SDoc -> SDoc
    $$ SyntaxExprTc -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr SyntaxExpr GhcTc
    SyntaxExprTc
    geq SDoc -> SDoc -> SDoc
    $$ SyntaxExprTc -> SDoc
    forall a. Outputable a => a -> SDoc
    ppr SyntaxExpr GhcTc
    SyntaxExprTc
    subtract
        go1 Pat GhcTc
    _                   = ([Id], [Id])
    forall {a} {a}. ([a], [a])
    empty

        goConDetails :: HsConPatDetails GhcTc -> ([TyVar], [EvVar])
        goConDetails :: HsConPatDetails GhcTc -> ([Id], [Id])
    goConDetails (PrefixCon [HsPatSigType (NoGhcTc GhcTc)]
    _ [LPat GhcTc]
    ps) = [([Id], [Id])] -> ([Id], [Id])
    forall {a} {a}. [([a], [a])] -> ([a], [a])
    mergeMany ([([Id], [Id])] -> ([Id], [Id]))
    -> ([LPat GhcTc] -> [([Id], [Id])]) -> [LPat GhcTc] -> ([Id], [Id])
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . (GenLocated SrcSpanAnnA (Pat GhcTc) -> ([Id], [Id]))
    -> [GenLocated SrcSpanAnnA (Pat GhcTc)] -> [([Id], [Id])]
    forall a b. (a -> b) -> [a] -> [b]
    map GenLocated SrcSpanAnnA (Pat GhcTc) -> ([Id], [Id])
    LPat GhcTc -> ([Id], [Id])
    go ([LPat GhcTc] -> ([Id], [Id])) -> [LPat GhcTc] -> ([Id], [Id])
    forall a b. (a -> b) -> a -> b
    $ [LPat GhcTc]
    ps
        goConDetails (InfixCon LPat GhcTc
    p1 LPat GhcTc
    p2) = LPat GhcTc -> ([Id], [Id])
    go LPat GhcTc
    p1 ([Id], [Id]) -> ([Id], [Id]) -> ([Id], [Id])
    forall {a} {a}. ([a], [a]) -> ([a], [a]) -> ([a], [a])
    `merge` LPat GhcTc -> ([Id], [Id])
    go LPat GhcTc
    p2
        goConDetails (RecCon HsRecFields{ rec_flds :: forall p arg. HsRecFields p arg -> [LHsRecField p arg]
    rec_flds = [LHsRecField GhcTc (LPat GhcTc)]
    flds })
          = [([Id], [Id])] -> ([Id], [Id])
    forall {a} {a}. [([a], [a])] -> ([a], [a])
    mergeMany ([([Id], [Id])] -> ([Id], [Id]))
    -> ([LHsRecField GhcTc (LPat GhcTc)] -> [([Id], [Id])])
    -> [LHsRecField GhcTc (LPat GhcTc)]
    -> ([Id], [Id])
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . (GenLocated
       SrcSpanAnnA
       (HsRecField' (FieldOcc GhcTc) (GenLocated SrcSpanAnnA (Pat GhcTc)))
     -> ([Id], [Id]))
    -> [GenLocated
          SrcSpanAnnA
          (HsRecField'
             (FieldOcc GhcTc) (GenLocated SrcSpanAnnA (Pat GhcTc)))]
    -> [([Id], [Id])]
    forall a b. (a -> b) -> [a] -> [b]
    map GenLocated
      SrcSpanAnnA
      (HsRecField' (FieldOcc GhcTc) (GenLocated SrcSpanAnnA (Pat GhcTc)))
    -> ([Id], [Id])
    LHsRecField GhcTc (LPat GhcTc) -> ([Id], [Id])
    goRecFd ([LHsRecField GhcTc (LPat GhcTc)] -> ([Id], [Id]))
    -> [LHsRecField GhcTc (LPat GhcTc)] -> ([Id], [Id])
    forall a b. (a -> b) -> a -> b
    $ [LHsRecField GhcTc (LPat GhcTc)]
    flds

        goRecFd :: LHsRecField GhcTc (LPat GhcTc) -> ([TyVar], [EvVar])
        goRecFd :: LHsRecField GhcTc (LPat GhcTc) -> ([Id], [Id])
    goRecFd (L SrcSpanAnnA
    _ HsRecField{ hsRecFieldArg :: forall id arg. HsRecField' id arg -> arg
    hsRecFieldArg = GenLocated SrcSpanAnnA (Pat GhcTc)
    p }) = LPat GhcTc -> ([Id], [Id])
    go GenLocated SrcSpanAnnA (Pat GhcTc)
    LPat GhcTc
    p

        merge :: ([a], [a]) -> ([a], [a]) -> ([a], [a])
    merge ([a]
    vs1, [a]
    evs1) ([a]
    vs2, [a]
    evs2) = ([a]
    vs1 [a] -> [a] -> [a]
    forall a. [a] -> [a] -> [a]
    ++ [a]
    vs2, [a]
    evs1 [a] -> [a] -> [a]
    forall a. [a] -> [a] -> [a]
    ++ [a]
    evs2)
        mergeMany :: [([a], [a])] -> ([a], [a])
    mergeMany = (([a], [a]) -> ([a], [a]) -> ([a], [a]))
    -> ([a], [a]) -> [([a], [a])] -> ([a], [a])
    forall (t :: * -> *) a b.
    Foldable t =>
    (a -> b -> b) -> b -> t a -> b
    foldr ([a], [a]) -> ([a], [a]) -> ([a], [a])
    forall {a} {a}. ([a], [a]) -> ([a], [a]) -> ([a], [a])
    merge ([a], [a])
    forall {a} {a}. ([a], [a])
    empty
        empty :: ([a], [a])
    empty     = ([], [])