{-# LANGUAGE CPP, PatternGuards, TypeFamilies #-}
-----------------------------------------------------------------------------
-- |
-- Module : Haddock.Convert
-- Copyright : (c) Isaac Dupree 2009,
-- License : BSD-like
--
-- Maintainer : haddock@projects.haskell.org
-- Stability : experimental
-- Portability : portable
--
-- Conversion between TyThing and HsDecl. This functionality may be moved into
-- GHC at some point.
-----------------------------------------------------------------------------
module Haddock.Convert (
tyThingToLHsDecl,
synifyInstHead,
synifyFamInst,
PrintRuntimeReps(..),
) where
import Bag ( emptyBag )
import BasicTypes ( TupleSort(..), SourceText(..), LexicalFixity(..)
, PromotionFlag(..), DefMethSpec(..) )
import Class
import CoAxiom
import ConLike
import Data.Either (lefts, rights)
import DataCon
import FamInstEnv
import GHC.Hs
import Name
import NameSet ( emptyNameSet )
import RdrName ( mkVarUnqual )
import PatSyn
import SrcLoc ( Located, noLoc, unLoc, GenLocated(..), srcLocSpan )
import TcType
import TyCon
import Type
import TyCoRep
import TysPrim ( alphaTyVars )
import TysWiredIn ( eqTyConName, listTyConName, liftedTypeKindTyConName
, unitTy, promotedNilDataCon, promotedConsDataCon )
import PrelNames ( hasKey, eqTyConKey, ipClassKey, tYPETyConKey
, liftedRepDataConKey )
import Unique ( getUnique )
import Util ( chkAppend, dropList, filterByList, filterOut )
import Var
import VarSet
import Haddock.Types
import Haddock.Interface.Specialize
import Haddock.GhcUtils ( orderedFVs, defaultRuntimeRepVars )
import Data.Maybe ( catMaybes, maybeToList )
-- | Whether or not to default 'RuntimeRep' variables to 'LiftedRep'. Check
-- out Note [Defaulting RuntimeRep variables] in IfaceType.hs for the
-- motivation.
data PrintRuntimeReps = ShowRuntimeRep | HideRuntimeRep deriving Show
-- the main function here! yay!
tyThingToLHsDecl
:: PrintRuntimeReps
-> TyThing
-> Either ErrMsg ([ErrMsg], (HsDecl GhcRn))
tyThingToLHsDecl prr t = case t of
-- ids (functions and zero-argument a.k.a. CAFs) get a type signature.
-- Including built-in functions like seq.
-- foreign-imported functions could be represented with ForD
-- instead of SigD if we wanted...
--
-- in a future code version we could turn idVarDetails = foreign-call
-- into a ForD instead of a SigD if we wanted. Haddock doesn't
-- need to care.
AnId i -> allOK $ SigD noExtField (synifyIdSig prr ImplicitizeForAll [] i)
-- type-constructors (e.g. Maybe) are complicated, put the definition
-- later in the file (also it's used for class associated-types too.)
ATyCon tc
| Just cl <- tyConClass_maybe tc -- classes are just a little tedious
-> let extractFamilyDecl :: TyClDecl a -> Either ErrMsg (FamilyDecl a)
extractFamilyDecl (FamDecl _ d) = return d
extractFamilyDecl _ =
Left "tyThingToLHsDecl: impossible associated tycon"
extractFamDefDecl :: FamilyDecl GhcRn -> Type -> TyFamDefltDecl GhcRn
extractFamDefDecl fd rhs =
TyFamInstDecl $ HsIB { hsib_ext = hsq_ext (fdTyVars fd)
, hsib_body = FamEqn
{ feqn_ext = noExtField
, feqn_tycon = fdLName fd
, feqn_bndrs = Nothing
, feqn_pats = map (HsValArg . hsLTyVarBndrToType) $
hsq_explicit $ fdTyVars fd
, feqn_fixity = fdFixity fd
, feqn_rhs = synifyType WithinType [] rhs }}
extractAtItem
:: ClassATItem
-> Either ErrMsg (LFamilyDecl GhcRn, Maybe (LTyFamDefltDecl GhcRn))
extractAtItem (ATI at_tc def) = do
tyDecl <- synifyTyCon prr Nothing at_tc
famDecl <- extractFamilyDecl tyDecl
let defEqnTy = fmap (noLoc . extractFamDefDecl famDecl . fst) def
pure (noLoc famDecl, defEqnTy)
atTyClDecls = map extractAtItem (classATItems cl)
(atFamDecls, atDefFamDecls) = unzip (rights atTyClDecls)
vs = tyConVisibleTyVars (classTyCon cl)
in withErrs (lefts atTyClDecls) . TyClD noExtField $ ClassDecl
{ tcdCtxt = synifyCtx (classSCTheta cl)
, tcdLName = synifyName cl
, tcdTyVars = synifyTyVars vs
, tcdFixity = synifyFixity cl
, tcdFDs = map (\ (l,r) -> noLoc
(map (noLoc . getName) l, map (noLoc . getName) r) ) $
snd $ classTvsFds cl
, tcdSigs = noLoc (MinimalSig noExtField NoSourceText . noLoc . fmap noLoc $ classMinimalDef cl) :
[ noLoc tcdSig
| clsOp <- classOpItems cl
, tcdSig <- synifyTcIdSig vs clsOp ]
, tcdMeths = emptyBag --ignore default method definitions, they don't affect signature
-- class associated-types are a subset of TyCon:
, tcdATs = atFamDecls
, tcdATDefs = catMaybes atDefFamDecls
, tcdDocs = [] --we don't have any docs at this point
, tcdCExt = placeHolderNamesTc }
| otherwise
-> synifyTyCon prr Nothing tc >>= allOK . TyClD noExtField
-- type-constructors (e.g. Maybe) are complicated, put the definition
-- later in the file (also it's used for class associated-types too.)
ACoAxiom ax -> synifyAxiom ax >>= allOK
-- a data-constructor alone just gets rendered as a function:
AConLike (RealDataCon dc) -> allOK $ SigD noExtField (TypeSig noExtField [synifyName dc]
(synifySigWcType ImplicitizeForAll [] (dataConUserType dc)))
AConLike (PatSynCon ps) ->
allOK . SigD noExtField $ PatSynSig noExtField [synifyName ps] (synifyPatSynSigType ps)
where
withErrs e x = return (e, x)
allOK x = return (mempty, x)
synifyAxBranch :: TyCon -> CoAxBranch -> TyFamInstEqn GhcRn
synifyAxBranch tc (CoAxBranch { cab_tvs = tkvs, cab_lhs = args, cab_rhs = rhs })
= let name = synifyName tc
args_types_only = filterOutInvisibleTypes tc args
typats = map (synifyType WithinType []) args_types_only
annot_typats = zipWith3 annotHsType args_poly args_types_only typats
hs_rhs = synifyType WithinType [] rhs
in HsIB { hsib_ext = map tyVarName tkvs
, hsib_body = FamEqn { feqn_ext = noExtField
, feqn_tycon = name
, feqn_bndrs = Nothing
-- TODO: this must change eventually
, feqn_pats = map HsValArg annot_typats
, feqn_fixity = synifyFixity name
, feqn_rhs = hs_rhs } }
where
args_poly = tyConArgsPolyKinded tc
synifyAxiom :: CoAxiom br -> Either ErrMsg (HsDecl GhcRn)
synifyAxiom ax@(CoAxiom { co_ax_tc = tc })
| isOpenTypeFamilyTyCon tc
, Just branch <- coAxiomSingleBranch_maybe ax
= return $ InstD noExtField
$ TyFamInstD noExtField
$ TyFamInstDecl { tfid_eqn = synifyAxBranch tc branch }
| Just ax' <- isClosedSynFamilyTyConWithAxiom_maybe tc
, getUnique ax' == getUnique ax -- without the getUniques, type error
= synifyTyCon ShowRuntimeRep (Just ax) tc >>= return . TyClD noExtField
| otherwise
= Left "synifyAxiom: closed/open family confusion"
-- | Turn type constructors into data declarations, type families, or type synonyms
synifyTyCon
:: PrintRuntimeReps
-> Maybe (CoAxiom br) -- ^ RHS of type synonym
-> TyCon -- ^ type constructor to convert
-> Either ErrMsg (TyClDecl GhcRn)
synifyTyCon prr _coax tc
| isFunTyCon tc || isPrimTyCon tc
= return $
DataDecl { tcdLName = synifyName tc
, tcdTyVars = HsQTvs { hsq_ext = [] -- No kind polymorphism
, hsq_explicit = zipWith mk_hs_tv
tyVarKinds
alphaTyVars --a, b, c... which are unfortunately all kind *
}
, tcdFixity = synifyFixity tc
, tcdDataDefn = HsDataDefn { dd_ext = noExtField
, dd_ND = DataType -- arbitrary lie, they are neither
-- algebraic data nor newtype:
, dd_ctxt = noLoc []
, dd_cType = Nothing
, dd_kindSig = synifyDataTyConReturnKind tc
-- we have their kind accurately:
, dd_cons = [] -- No constructors
, dd_derivs = noLoc [] }
, tcdDExt = DataDeclRn False placeHolderNamesTc }
where
-- tyConTyVars doesn't work on fun/prim, but we can make them up:
mk_hs_tv realKind fakeTyVar
| isLiftedTypeKind realKind = noLoc $ UserTyVar noExtField (noLoc (getName fakeTyVar))
| otherwise = noLoc $ KindedTyVar noExtField (noLoc (getName fakeTyVar)) (synifyKindSig realKind)
conKind = defaultType prr (tyConKind tc)
tyVarKinds = fst . splitFunTys . snd . splitPiTysInvisible $ conKind
synifyTyCon _prr _coax tc
| Just flav <- famTyConFlav_maybe tc
= case flav of
-- Type families
OpenSynFamilyTyCon -> mkFamDecl OpenTypeFamily
ClosedSynFamilyTyCon mb
| Just (CoAxiom { co_ax_branches = branches }) <- mb
-> mkFamDecl $ ClosedTypeFamily $ Just
$ map (noLoc . synifyAxBranch tc) (fromBranches branches)
| otherwise
-> mkFamDecl $ ClosedTypeFamily $ Just []
BuiltInSynFamTyCon {}
-> mkFamDecl $ ClosedTypeFamily $ Just []
AbstractClosedSynFamilyTyCon {}
-> mkFamDecl $ ClosedTypeFamily Nothing
DataFamilyTyCon {}
-> mkFamDecl DataFamily
where
resultVar = famTcResVar tc
mkFamDecl i = return $ FamDecl noExtField $
FamilyDecl { fdExt = noExtField
, fdInfo = i
, fdLName = synifyName tc
, fdTyVars = synifyTyVars (tyConVisibleTyVars tc)
, fdFixity = synifyFixity tc
, fdResultSig =
synifyFamilyResultSig resultVar (tyConResKind tc)
, fdInjectivityAnn =
synifyInjectivityAnn resultVar (tyConTyVars tc)
(tyConInjectivityInfo tc)
}
synifyTyCon _prr coax tc
| Just ty <- synTyConRhs_maybe tc
= return $ SynDecl { tcdSExt = emptyNameSet
, tcdLName = synifyName tc
, tcdTyVars = synifyTyVars (tyConVisibleTyVars tc)
, tcdFixity = synifyFixity tc
, tcdRhs = synifyType WithinType [] ty }
| otherwise =
-- (closed) newtype and data
let
alg_nd = if isNewTyCon tc then NewType else DataType
alg_ctx = synifyCtx (tyConStupidTheta tc)
name = case coax of
Just a -> synifyName a -- Data families are named according to their
-- CoAxioms, not their TyCons
_ -> synifyName tc
tyvars = synifyTyVars (tyConVisibleTyVars tc)
kindSig = synifyDataTyConReturnKind tc
-- The data constructors.
--
-- Any data-constructors not exported from the module that *defines* the
-- type will not (cannot) be included.
--
-- Very simple constructors, Haskell98 with no existentials or anything,
-- probably look nicer in non-GADT syntax. In source code, all constructors
-- must be declared with the same (GADT vs. not) syntax, and it probably
-- is less confusing to follow that principle for the documentation as well.
--
-- There is no sensible infix-representation for GADT-syntax constructor
-- declarations. They cannot be made in source code, but we could end up
-- with some here in the case where some constructors use existentials.
-- That seems like an acceptable compromise (they'll just be documented
-- in prefix position), since, otherwise, the logic (at best) gets much more
-- complicated. (would use dataConIsInfix.)
use_gadt_syntax = isGadtSyntaxTyCon tc
consRaw = map (synifyDataCon use_gadt_syntax) (tyConDataCons tc)
cons = rights consRaw
-- "deriving" doesn't affect the signature, no need to specify any.
alg_deriv = noLoc []
defn = HsDataDefn { dd_ext = noExtField
, dd_ND = alg_nd
, dd_ctxt = alg_ctx
, dd_cType = Nothing
, dd_kindSig = kindSig
, dd_cons = cons
, dd_derivs = alg_deriv }
in case lefts consRaw of
[] -> return $
DataDecl { tcdLName = name, tcdTyVars = tyvars
, tcdFixity = synifyFixity name
, tcdDataDefn = defn
, tcdDExt = DataDeclRn False placeHolderNamesTc }
dataConErrs -> Left $ unlines dataConErrs
-- | In this module, every TyCon being considered has come from an interface
-- file. This means that when considering a data type constructor such as:
--
-- > data Foo (w :: *) (m :: * -> *) (a :: *)
--
-- Then its tyConKind will be (* -> (* -> *) -> * -> *). But beware! We are
-- also rendering the type variables of Foo, so if we synify the tyConKind of
-- Foo in full, we will end up displaying this in Haddock:
--
-- > data Foo (w :: *) (m :: * -> *) (a :: *)
-- > :: * -> (* -> *) -> * -> *
--
-- Which is entirely wrong (#548). We only want to display the /return/ kind,
-- which this function obtains.
synifyDataTyConReturnKind :: TyCon -> Maybe (LHsKind GhcRn)
synifyDataTyConReturnKind tc
| isLiftedTypeKind ret_kind = Nothing -- Don't bother displaying :: *
| otherwise = Just (synifyKindSig ret_kind)
where ret_kind = tyConResKind tc
synifyInjectivityAnn :: Maybe Name -> [TyVar] -> Injectivity
-> Maybe (LInjectivityAnn GhcRn)
synifyInjectivityAnn Nothing _ _ = Nothing
synifyInjectivityAnn _ _ NotInjective = Nothing
synifyInjectivityAnn (Just lhs) tvs (Injective inj) =
let rhs = map (noLoc . tyVarName) (filterByList inj tvs)
in Just $ noLoc $ InjectivityAnn (noLoc lhs) rhs
synifyFamilyResultSig :: Maybe Name -> Kind -> LFamilyResultSig GhcRn
synifyFamilyResultSig Nothing kind
| isLiftedTypeKind kind = noLoc $ NoSig noExtField
| otherwise = noLoc $ KindSig noExtField (synifyKindSig kind)
synifyFamilyResultSig (Just name) kind =
noLoc $ TyVarSig noExtField (noLoc $ KindedTyVar noExtField (noLoc name) (synifyKindSig kind))
-- User beware: it is your responsibility to pass True (use_gadt_syntax)
-- for any constructor that would be misrepresented by omitting its
-- result-type.
-- But you might want pass False in simple enough cases,
-- if you think it looks better.
synifyDataCon :: Bool -> DataCon -> Either ErrMsg (LConDecl GhcRn)
synifyDataCon use_gadt_syntax dc =
let
-- dataConIsInfix allegedly tells us whether it was declared with
-- infix *syntax*.
use_infix_syntax = dataConIsInfix dc
use_named_field_syntax = not (null field_tys)
name = synifyName dc
-- con_qvars means a different thing depending on gadt-syntax
(_univ_tvs, ex_tvs, _eq_spec, theta, arg_tys, res_ty) = dataConFullSig dc
user_tvs = dataConUserTyVars dc -- Used for GADT data constructors
-- skip any EqTheta, use 'orig'inal syntax
ctx | null theta = Nothing
| otherwise = Just $ synifyCtx theta
linear_tys =
zipWith (\ty bang ->
let tySyn = synifyType WithinType [] ty
in case bang of
(HsSrcBang _ NoSrcUnpack NoSrcStrict) -> tySyn
bang' -> noLoc $ HsBangTy noExtField bang' tySyn)
arg_tys (dataConSrcBangs dc)
field_tys = zipWith con_decl_field (dataConFieldLabels dc) linear_tys
con_decl_field fl synTy = noLoc $
ConDeclField noExtField [noLoc $ FieldOcc (flSelector fl) (noLoc $ mkVarUnqual $ flLabel fl)] synTy
Nothing
hs_arg_tys = case (use_named_field_syntax, use_infix_syntax) of
(True,True) -> Left "synifyDataCon: contradiction!"
(True,False) -> return $ RecCon (noLoc field_tys)
(False,False) -> return $ PrefixCon linear_tys
(False,True) -> case linear_tys of
[a,b] -> return $ InfixCon a b
_ -> Left "synifyDataCon: infix with non-2 args?"
-- finally we get synifyDataCon's result!
in hs_arg_tys >>=
\hat ->
if use_gadt_syntax
then return $ noLoc $
ConDeclGADT { con_g_ext = noExtField
, con_names = [name]
, con_forall = noLoc $ not $ null user_tvs
, con_qvars = synifyTyVars user_tvs
, con_mb_cxt = ctx
, con_args = hat
, con_res_ty = synifyType WithinType [] res_ty
, con_doc = Nothing }
else return $ noLoc $
ConDeclH98 { con_ext = noExtField
, con_name = name
, con_forall = noLoc False
, con_ex_tvs = map synifyTyVar ex_tvs
, con_mb_cxt = ctx
, con_args = hat
, con_doc = Nothing }
synifyName :: NamedThing n => n -> Located Name
synifyName n = L (srcLocSpan (getSrcLoc n)) (getName n)
-- | Guess the fixity of a something with a name. This isn't quite right, since
-- a user can always declare an infix name in prefix form or a prefix name in
-- infix form. Unfortunately, that is not something we can usually reconstruct.
synifyFixity :: NamedThing n => n -> LexicalFixity
synifyFixity n | isSymOcc (getOccName n) = Infix
| otherwise = Prefix
synifyIdSig
:: PrintRuntimeReps -- ^ are we printing tyvars of kind 'RuntimeRep'?
-> SynifyTypeState -- ^ what to do with a 'forall'
-> [TyVar] -- ^ free variables in the type to convert
-> Id -- ^ the 'Id' from which to get the type signature
-> Sig GhcRn
synifyIdSig prr s vs i = TypeSig noExtField [synifyName i] (synifySigWcType s vs t)
where
t = defaultType prr (varType i)
-- | Turn a 'ClassOpItem' into a list of signatures. The list returned is going
-- to contain the synified 'ClassOpSig' as well (when appropriate) a default
-- 'ClassOpSig'.
synifyTcIdSig :: [TyVar] -> ClassOpItem -> [Sig GhcRn]
synifyTcIdSig vs (i, dm) =
[ ClassOpSig noExtField False [synifyName i] (mainSig (varType i)) ] ++
[ ClassOpSig noExtField True [noLoc dn] (defSig dt)
| Just (dn, GenericDM dt) <- [dm] ]
where
mainSig t = synifySigType DeleteTopLevelQuantification vs t
defSig t = synifySigType ImplicitizeForAll vs t
synifyCtx :: [PredType] -> LHsContext GhcRn
synifyCtx = noLoc . map (synifyType WithinType [])
synifyTyVars :: [TyVar] -> LHsQTyVars GhcRn
synifyTyVars ktvs = HsQTvs { hsq_ext = []
, hsq_explicit = map synifyTyVar ktvs }
synifyTyVar :: TyVar -> LHsTyVarBndr GhcRn
synifyTyVar = synifyTyVar' emptyVarSet
-- | Like 'synifyTyVar', but accepts a set of variables for which to omit kind
-- signatures (even if they don't have the lifted type kind).
synifyTyVar' :: VarSet -> TyVar -> LHsTyVarBndr GhcRn
synifyTyVar' no_kinds tv
| isLiftedTypeKind kind || tv `elemVarSet` no_kinds
= noLoc (UserTyVar noExtField (noLoc name))
| otherwise = noLoc (KindedTyVar noExtField (noLoc name) (synifyKindSig kind))
where
kind = tyVarKind tv
name = getName tv
-- | Annotate (with HsKingSig) a type if the first parameter is True
-- and if the type contains a free variable.
-- This is used to synify type patterns for poly-kinded tyvars in
-- synifying class and type instances.
annotHsType :: Bool -- True <=> annotate
-> Type -> LHsType GhcRn -> LHsType GhcRn
-- tiny optimization: if the type is annotated, don't annotate again.
annotHsType _ _ hs_ty@(L _ (HsKindSig {})) = hs_ty
annotHsType True ty hs_ty
| not $ isEmptyVarSet $ filterVarSet isTyVar $ tyCoVarsOfType ty
= let ki = typeKind ty
hs_ki = synifyType WithinType [] ki
in noLoc (HsKindSig noExtField hs_ty hs_ki)
annotHsType _ _ hs_ty = hs_ty
-- | For every argument type that a type constructor accepts,
-- report whether or not the argument is poly-kinded. This is used to
-- eventually feed into 'annotThType'.
tyConArgsPolyKinded :: TyCon -> [Bool]
tyConArgsPolyKinded tc =
map (is_poly_ty . tyVarKind) tc_vis_tvs
++ map (is_poly_ty . tyCoBinderType) tc_res_kind_vis_bndrs
++ repeat True
where
is_poly_ty :: Type -> Bool
is_poly_ty ty = not $
isEmptyVarSet $
filterVarSet isTyVar $
tyCoVarsOfType ty
tc_vis_tvs :: [TyVar]
tc_vis_tvs = tyConVisibleTyVars tc
tc_res_kind_vis_bndrs :: [TyCoBinder]
tc_res_kind_vis_bndrs = filter isVisibleBinder $ fst $ splitPiTys $ tyConResKind tc
--states of what to do with foralls:
data SynifyTypeState
= WithinType
-- ^ normal situation. This is the safe one to use if you don't
-- quite understand what's going on.
| ImplicitizeForAll
-- ^ beginning of a function definition, in which, to make it look
-- less ugly, those rank-1 foralls (without kind annotations) are made
-- implicit.
| DeleteTopLevelQuantification
-- ^ because in class methods the context is added to the type
-- (e.g. adding @forall a. Num a =>@ to @(+) :: a -> a -> a@)
-- which is rather sensible,
-- but we want to restore things to the source-syntax situation where
-- the defining class gets to quantify all its functions for free!
synifySigType :: SynifyTypeState -> [TyVar] -> Type -> LHsSigType GhcRn
-- The empty binders is a bit suspicious;
-- what if the type has free variables?
synifySigType s vs ty = mkEmptyImplicitBndrs (synifyType s vs ty)
synifySigWcType :: SynifyTypeState -> [TyVar] -> Type -> LHsSigWcType GhcRn
-- Ditto (see synifySigType)
synifySigWcType s vs ty = mkEmptyWildCardBndrs (mkEmptyImplicitBndrs (synifyType s vs ty))
synifyPatSynSigType :: PatSyn -> LHsSigType GhcRn
-- Ditto (see synifySigType)
synifyPatSynSigType ps = mkEmptyImplicitBndrs (synifyPatSynType ps)
-- | Depending on the first argument, try to default all type variables of kind
-- 'RuntimeRep' to 'LiftedType'.
defaultType :: PrintRuntimeReps -> Type -> Type
defaultType ShowRuntimeRep = id
defaultType HideRuntimeRep = defaultRuntimeRepVars
-- | Convert a core type into an 'HsType'.
synifyType
:: SynifyTypeState -- ^ what to do with a 'forall'
-> [TyVar] -- ^ free variables in the type to convert
-> Type -- ^ the type to convert
-> LHsType GhcRn
synifyType _ _ (TyVarTy tv) = noLoc $ HsTyVar noExtField NotPromoted $ noLoc (getName tv)
synifyType _ vs (TyConApp tc tys)
= maybe_sig res_ty
where
res_ty :: LHsType GhcRn
res_ty
-- Use */# instead of TYPE 'Lifted/TYPE 'Unlifted (#473)
| tc `hasKey` tYPETyConKey
, [TyConApp lev []] <- tys
, lev `hasKey` liftedRepDataConKey
= noLoc (HsTyVar noExtField NotPromoted (noLoc liftedTypeKindTyConName))
-- Use non-prefix tuple syntax where possible, because it looks nicer.
| Just sort <- tyConTuple_maybe tc
, tyConArity tc == tys_len
= noLoc $ HsTupleTy noExtField
(case sort of
BoxedTuple -> HsBoxedTuple
ConstraintTuple -> HsConstraintTuple
UnboxedTuple -> HsUnboxedTuple)
(map (synifyType WithinType vs) vis_tys)
| isUnboxedSumTyCon tc = noLoc $ HsSumTy noExtField (map (synifyType WithinType vs) vis_tys)
| Just dc <- isPromotedDataCon_maybe tc
, isTupleDataCon dc
, dataConSourceArity dc == length vis_tys
= noLoc $ HsExplicitTupleTy noExtField (map (synifyType WithinType vs) vis_tys)
-- ditto for lists
| getName tc == listTyConName, [ty] <- vis_tys =
noLoc $ HsListTy noExtField (synifyType WithinType vs ty)
| tc == promotedNilDataCon, [] <- vis_tys
= noLoc $ HsExplicitListTy noExtField IsPromoted []
| tc == promotedConsDataCon
, [ty1, ty2] <- vis_tys
= let hTy = synifyType WithinType vs ty1
in case synifyType WithinType vs ty2 of
tTy | L _ (HsExplicitListTy _ IsPromoted tTy') <- stripKindSig tTy
-> noLoc $ HsExplicitListTy noExtField IsPromoted (hTy : tTy')
| otherwise
-> noLoc $ HsOpTy noExtField hTy (noLoc $ getName tc) tTy
-- ditto for implicit parameter tycons
| tc `hasKey` ipClassKey
, [name, ty] <- tys
, Just x <- isStrLitTy name
= noLoc $ HsIParamTy noExtField (noLoc $ HsIPName x) (synifyType WithinType vs ty)
-- and equalities
| tc `hasKey` eqTyConKey
, [ty1, ty2] <- tys
= noLoc $ HsOpTy noExtField
(synifyType WithinType vs ty1)
(noLoc eqTyConName)
(synifyType WithinType vs ty2)
-- and infix type operators
| isSymOcc (nameOccName (getName tc))
, ty1:ty2:tys_rest <- vis_tys
= mk_app_tys (HsOpTy noExtField
(synifyType WithinType vs ty1)
(noLoc $ getName tc)
(synifyType WithinType vs ty2))
tys_rest
-- Most TyCons:
| otherwise
= mk_app_tys (HsTyVar noExtField prom $ noLoc (getName tc))
vis_tys
where
prom = if isPromotedDataCon tc then IsPromoted else NotPromoted
mk_app_tys ty_app ty_args =
foldl (\t1 t2 -> noLoc $ HsAppTy noExtField t1 t2)
(noLoc ty_app)
(map (synifyType WithinType vs) $
filterOut isCoercionTy ty_args)
tys_len = length tys
vis_tys = filterOutInvisibleTypes tc tys
maybe_sig :: LHsType GhcRn -> LHsType GhcRn
maybe_sig ty'
| tyConAppNeedsKindSig False tc tys_len
= let full_kind = typeKind (mkTyConApp tc tys)
full_kind' = synifyType WithinType vs full_kind
in noLoc $ HsKindSig noExtField ty' full_kind'
| otherwise = ty'
synifyType _ vs ty@(AppTy {}) = let
(ty_head, ty_args) = splitAppTys ty
ty_head' = synifyType WithinType vs ty_head
ty_args' = map (synifyType WithinType vs) $
filterOut isCoercionTy $
filterByList (map isVisibleArgFlag $ appTyArgFlags ty_head ty_args)
ty_args
in foldl (\t1 t2 -> noLoc $ HsAppTy noExtField t1 t2) ty_head' ty_args'
synifyType s vs funty@(FunTy InvisArg _ _) = synifyForAllType s Inferred vs funty
synifyType _ vs (FunTy VisArg t1 t2) = let
s1 = synifyType WithinType vs t1
s2 = synifyType WithinType vs t2
in noLoc $ HsFunTy noExtField s1 s2
synifyType s vs forallty@(ForAllTy (Bndr _ argf) _ty) =
synifyForAllType s argf vs forallty
synifyType _ _ (LitTy t) = noLoc $ HsTyLit noExtField $ synifyTyLit t
synifyType s vs (CastTy t _) = synifyType s vs t
synifyType _ _ (CoercionTy {}) = error "synifyType:Coercion"
-- | Process a 'Type' which starts with a forall or a constraint into
-- an 'HsType'
synifyForAllType
:: SynifyTypeState -- ^ what to do with the 'forall'
-> ArgFlag -- ^ the visibility of the @forall@
-> [TyVar] -- ^ free variables in the type to convert
-> Type -- ^ the forall type to convert
-> LHsType GhcRn
synifyForAllType s argf vs ty =
let (tvs, ctx, tau) = tcSplitSigmaTySameVisPreserveSynonyms argf ty
sPhi = HsQualTy { hst_ctxt = synifyCtx ctx
, hst_xqual = noExtField
, hst_body = synifyType WithinType (tvs' ++ vs) tau }
sTy = HsForAllTy { hst_fvf = argToForallVisFlag argf
, hst_bndrs = sTvs
, hst_xforall = noExtField
, hst_body = noLoc sPhi }
sTvs = map synifyTyVar tvs
-- Figure out what the type variable order would be inferred in the
-- absence of an explicit forall
tvs' = orderedFVs (mkVarSet vs) (ctx ++ [tau])
in case s of
DeleteTopLevelQuantification -> synifyType ImplicitizeForAll (tvs' ++ vs) tau
-- Put a forall in if there are any type variables
WithinType
| not (null tvs) -> noLoc sTy
| otherwise -> noLoc sPhi
ImplicitizeForAll -> implicitForAll [] vs tvs ctx (synifyType WithinType) tau
-- | Put a forall in if there are any type variables which require
-- explicit kind annotations or if the inferred type variable order
-- would be different.
implicitForAll
:: [TyCon] -- ^ type constructors that determine their args kinds
-> [TyVar] -- ^ free variables in the type to convert
-> [TyVar] -- ^ type variable binders in the forall
-> ThetaType -- ^ constraints right after the forall
-> ([TyVar] -> Type -> LHsType GhcRn) -- ^ how to convert the inner type
-> Type -- ^ inner type
-> LHsType GhcRn
implicitForAll tycons vs tvs ctx synInner tau
| any (isHsKindedTyVar . unLoc) sTvs = noLoc sTy
| tvs' /= tvs = noLoc sTy
| otherwise = noLoc sPhi
where
sRho = synInner (tvs' ++ vs) tau
sPhi | null ctx = unLoc sRho
| otherwise
= HsQualTy { hst_ctxt = synifyCtx ctx
, hst_xqual = noExtField
, hst_body = synInner (tvs' ++ vs) tau }
sTy = HsForAllTy { hst_fvf = ForallInvis
, hst_bndrs = sTvs
, hst_xforall = noExtField
, hst_body = noLoc sPhi }
no_kinds_needed = noKindTyVars tycons tau
sTvs = map (synifyTyVar' no_kinds_needed) tvs
-- Figure out what the type variable order would be inferred in the
-- absence of an explicit forall
tvs' = orderedFVs (mkVarSet vs) (ctx ++ [tau])
-- | Find the set of type variables whose kind signatures can be properly
-- inferred just from their uses in the type signature. This means the type
-- variable to has at least one fully applied use @f x1 x2 ... xn@ where:
--
-- * @f@ has a function kind where the arguments have the same kinds
-- as @x1 x2 ... xn@.
--
-- * @f@ has a function kind whose final return has lifted type kind
--
noKindTyVars
:: [TyCon] -- ^ type constructors that determine their args kinds
-> Type -- ^ type to inspect
-> VarSet -- ^ set of variables whose kinds can be inferred from uses in the type
noKindTyVars _ (TyVarTy var)
| isLiftedTypeKind (tyVarKind var) = unitVarSet var
noKindTyVars ts ty
| (f, xs) <- splitAppTys ty
, not (null xs)
= let args = map (noKindTyVars ts) xs
func = case f of
TyVarTy var | (xsKinds, outKind) <- splitFunTys (tyVarKind var)
, xsKinds `eqTypes` map typeKind xs
, isLiftedTypeKind outKind
-> unitVarSet var
TyConApp t ks | t `elem` ts
, all noFreeVarsOfType ks
-> mkVarSet [ v | TyVarTy v <- xs ]
_ -> noKindTyVars ts f
in unionVarSets (func : args)
noKindTyVars ts (ForAllTy _ t) = noKindTyVars ts t
noKindTyVars ts (FunTy _ t1 t2) = noKindTyVars ts t1 `unionVarSet` noKindTyVars ts t2
noKindTyVars ts (CastTy t _) = noKindTyVars ts t
noKindTyVars _ _ = emptyVarSet
synifyPatSynType :: PatSyn -> LHsType GhcRn
synifyPatSynType ps =
let (univ_tvs, req_theta, ex_tvs, prov_theta, arg_tys, res_ty) = patSynSig ps
ts = maybeToList (tyConAppTyCon_maybe res_ty)
-- HACK: a HsQualTy with theta = [unitTy] will be printed as "() =>",
-- i.e., an explicit empty context, which is what we need. This is not
-- possible by taking theta = [], as that will print no context at all
req_theta' | null req_theta
, not (null prov_theta && null ex_tvs)
= [unitTy]
| otherwise = req_theta
in implicitForAll ts [] (univ_tvs ++ ex_tvs) req_theta'
(\vs -> implicitForAll ts vs [] prov_theta (synifyType WithinType))
(mkVisFunTys arg_tys res_ty)
synifyTyLit :: TyLit -> HsTyLit
synifyTyLit (NumTyLit n) = HsNumTy NoSourceText n
synifyTyLit (StrTyLit s) = HsStrTy NoSourceText s
synifyKindSig :: Kind -> LHsKind GhcRn
synifyKindSig k = synifyType WithinType [] k
stripKindSig :: LHsType GhcRn -> LHsType GhcRn
stripKindSig (L _ (HsKindSig _ t _)) = t
stripKindSig t = t
synifyInstHead :: ([TyVar], [PredType], Class, [Type]) -> InstHead GhcRn
synifyInstHead (vs, preds, cls, types) = specializeInstHead $ InstHead
{ ihdClsName = getName cls
, ihdTypes = map unLoc annot_ts
, ihdInstType = ClassInst
{ clsiCtx = map (unLoc . synifyType WithinType []) preds
, clsiTyVars = synifyTyVars (tyConVisibleTyVars cls_tycon)
, clsiSigs = map synifyClsIdSig $ classMethods cls
, clsiAssocTys = do
(Right (FamDecl _ fam)) <- map (synifyTyCon HideRuntimeRep Nothing)
(classATs cls)
pure $ mkPseudoFamilyDecl fam
}
}
where
cls_tycon = classTyCon cls
ts = filterOutInvisibleTypes cls_tycon types
ts' = map (synifyType WithinType vs) ts
annot_ts = zipWith3 annotHsType args_poly ts ts'
args_poly = tyConArgsPolyKinded cls_tycon
synifyClsIdSig = synifyIdSig ShowRuntimeRep DeleteTopLevelQuantification vs
-- Convert a family instance, this could be a type family or data family
synifyFamInst :: FamInst -> Bool -> Either ErrMsg (InstHead GhcRn)
synifyFamInst fi opaque = do
ityp' <- ityp fam_flavor
return InstHead
{ ihdClsName = fi_fam fi
, ihdTypes = map unLoc annot_ts
, ihdInstType = ityp'
}
where
ityp SynFamilyInst | opaque = return $ TypeInst Nothing
ityp SynFamilyInst =
return . TypeInst . Just . unLoc $ synifyType WithinType [] fam_rhs
ityp (DataFamilyInst c) =
DataInst <$> synifyTyCon HideRuntimeRep (Just $ famInstAxiom fi) c
fam_tc = famInstTyCon fi
fam_flavor = fi_flavor fi
fam_lhs = fi_tys fi
fam_rhs = fi_rhs fi
eta_expanded_lhs
-- eta-expand lhs types, because sometimes data/newtype
-- instances are eta-reduced; See Trac #9692
-- See Note [Eta reduction for data family axioms] in TcInstDcls in GHC
| DataFamilyInst rep_tc <- fam_flavor
= let (_, rep_tc_args) = splitTyConApp fam_rhs
etad_tyvars = dropList rep_tc_args $ tyConTyVars rep_tc
etad_tys = mkTyVarTys etad_tyvars
eta_exp_lhs = fam_lhs `chkAppend` etad_tys
in eta_exp_lhs
| otherwise
= fam_lhs
ts = filterOutInvisibleTypes fam_tc eta_expanded_lhs
synifyTypes = map (synifyType WithinType [])
ts' = synifyTypes ts
annot_ts = zipWith3 annotHsType args_poly ts ts'
args_poly = tyConArgsPolyKinded fam_tc
{-
Note [Invariant: Never expand type synonyms]
In haddock, we never want to expand a type synonym that may be presented to the
user, as we want to keep the link to the abstraction captured in the synonym.
All code in Haddock.Convert must make sure that this invariant holds.
See https://github.com/haskell/haddock/issues/879 for a bug where this
invariant didn't hold.
-}
-- | A version of 'TcType.tcSplitSigmaTySameVis' that preserves type synonyms.
--
-- See Note [Invariant: Never expand type synonyms]
tcSplitSigmaTySameVisPreserveSynonyms :: ArgFlag -> Type -> ([TyVar], ThetaType, Type)
tcSplitSigmaTySameVisPreserveSynonyms argf ty =
case tcSplitForAllTysSameVisPreserveSynonyms argf ty of
(tvs, rho) -> case tcSplitPhiTyPreserveSynonyms rho of
(theta, tau) -> (tvs, theta, tau)
-- | See Note [Invariant: Never expand type synonyms]
tcSplitForAllTysSameVisPreserveSynonyms :: ArgFlag -> Type -> ([TyVar], Type)
tcSplitForAllTysSameVisPreserveSynonyms supplied_argf ty = split ty ty []
where
split _ (ForAllTy (Bndr tv argf) ty') tvs
| argf `sameVis` supplied_argf = split ty' ty' (tv:tvs)
split orig_ty _ tvs = (reverse tvs, orig_ty)
-- | See Note [Invariant: Never expand type synonyms]
tcSplitPhiTyPreserveSynonyms :: Type -> (ThetaType, Type)
tcSplitPhiTyPreserveSynonyms ty0 = split ty0 []
where
split ty ts
= case tcSplitPredFunTyPreserveSynonyms_maybe ty of
Just (pred_, ty') -> split ty' (pred_:ts)
Nothing -> (reverse ts, ty)
-- | See Note [Invariant: Never expand type synonyms]
tcSplitPredFunTyPreserveSynonyms_maybe :: Type -> Maybe (PredType, Type)
tcSplitPredFunTyPreserveSynonyms_maybe (FunTy InvisArg arg res) = Just (arg, res)
tcSplitPredFunTyPreserveSynonyms_maybe _ = Nothing