{- (c) The University of Glasgow 2006 (c) The GRASP/AQUA Project, Glasgow University, 1993-1998 This module defines interface types and binders -} {-# LANGUAGE CPP, FlexibleInstances, BangPatterns #-} {-# LANGUAGE MultiWayIf #-} {-# LANGUAGE TupleSections #-} -- FlexibleInstances for Binary (DefMethSpec IfaceType) module IfaceType ( IfExtName, IfLclName, IfaceType(..), IfacePredType, IfaceKind, IfaceCoercion(..), IfaceMCoercion(..), IfaceUnivCoProv(..), IfaceTyCon(..), IfaceTyConInfo(..), IfaceTyConSort(..), IfaceTyLit(..), IfaceAppArgs(..), IfaceContext, IfaceBndr(..), IfaceOneShot(..), IfaceLamBndr, IfaceTvBndr, IfaceIdBndr, IfaceTyConBinder, IfaceForAllBndr, ArgFlag(..), ShowForAllFlag(..), mkIfaceForAllTvBndr, ifForAllBndrVar, ifForAllBndrName, ifaceBndrName, ifTyConBinderVar, ifTyConBinderName, -- Equality testing isIfaceLiftedTypeKind, -- Conversion from IfaceAppArgs to IfaceTypes/ArgFlags appArgsIfaceTypes, appArgsIfaceTypesArgFlags, -- Printing pprIfaceType, pprParendIfaceType, pprPrecIfaceType, pprIfaceContext, pprIfaceContextArr, pprIfaceIdBndr, pprIfaceLamBndr, pprIfaceTvBndr, pprIfaceTyConBinders, pprIfaceBndrs, pprIfaceAppArgs, pprParendIfaceAppArgs, pprIfaceForAllPart, pprIfaceForAllPartMust, pprIfaceForAll, pprIfaceSigmaType, pprIfaceTyLit, pprIfaceCoercion, pprParendIfaceCoercion, splitIfaceSigmaTy, pprIfaceTypeApp, pprUserIfaceForAll, pprIfaceCoTcApp, pprTyTcApp, pprIfacePrefixApp, suppressIfaceInvisibles, stripIfaceInvisVars, stripInvisArgs, mkIfaceTySubst, substIfaceTyVar, substIfaceAppArgs, inDomIfaceTySubst ) where #include "HsVersions.h" import GhcPrelude import {-# SOURCE #-} TysWiredIn ( coercibleTyCon, heqTyCon , liftedRepDataConTyCon ) import {-# SOURCE #-} TyCoRep ( isRuntimeRepTy ) import DynFlags import TyCon hiding ( pprPromotionQuote ) import CoAxiom import Var import PrelNames import Name import BasicTypes import Binary import Outputable import FastString import FastStringEnv import Util import Data.Maybe( isJust ) import qualified Data.Semigroup as Semi {- ************************************************************************ * * Local (nested) binders * * ************************************************************************ -} type IfLclName = FastString -- A local name in iface syntax type IfExtName = Name -- An External or WiredIn Name can appear in IfaceSyn -- (However Internal or System Names never should) data IfaceBndr -- Local (non-top-level) binders = IfaceIdBndr {-# UNPACK #-} !IfaceIdBndr | IfaceTvBndr {-# UNPACK #-} !IfaceTvBndr type IfaceIdBndr = (IfLclName, IfaceType) type IfaceTvBndr = (IfLclName, IfaceKind) ifaceTvBndrName :: IfaceTvBndr -> IfLclName ifaceTvBndrName (n,_) = n ifaceIdBndrName :: IfaceIdBndr -> IfLclName ifaceIdBndrName (n,_) = n ifaceBndrName :: IfaceBndr -> IfLclName ifaceBndrName (IfaceTvBndr bndr) = ifaceTvBndrName bndr ifaceBndrName (IfaceIdBndr bndr) = ifaceIdBndrName bndr type IfaceLamBndr = (IfaceBndr, IfaceOneShot) data IfaceOneShot -- See Note [Preserve OneShotInfo] in CoreTicy = IfaceNoOneShot -- and Note [The oneShot function] in MkId | IfaceOneShot {- %************************************************************************ %* * IfaceType %* * %************************************************************************ -} ------------------------------- type IfaceKind = IfaceType -- | A kind of universal type, used for types and kinds. -- -- Any time a 'Type' is pretty-printed, it is first converted to an 'IfaceType' -- before being printed. See Note [Pretty printing via IfaceSyn] in PprTyThing data IfaceType = IfaceFreeTyVar TyVar -- See Note [Free tyvars in IfaceType] | IfaceTyVar IfLclName -- Type/coercion variable only, not tycon | IfaceLitTy IfaceTyLit | IfaceAppTy IfaceType IfaceAppArgs -- See Note [Suppressing invisible arguments] for -- an explanation of why the second field isn't -- IfaceType, analogous to AppTy. | IfaceFunTy IfaceType IfaceType | IfaceDFunTy IfaceType IfaceType | IfaceForAllTy IfaceForAllBndr IfaceType | IfaceTyConApp IfaceTyCon IfaceAppArgs -- Not necessarily saturated -- Includes newtypes, synonyms, tuples | IfaceCastTy IfaceType IfaceCoercion | IfaceCoercionTy IfaceCoercion | IfaceTupleTy -- Saturated tuples (unsaturated ones use IfaceTyConApp) TupleSort -- What sort of tuple? PromotionFlag -- A bit like IfaceTyCon IfaceAppArgs -- arity = length args -- For promoted data cons, the kind args are omitted type IfacePredType = IfaceType type IfaceContext = [IfacePredType] data IfaceTyLit = IfaceNumTyLit Integer | IfaceStrTyLit FastString deriving (Eq) type IfaceTyConBinder = VarBndr IfaceBndr TyConBndrVis type IfaceForAllBndr = VarBndr IfaceBndr ArgFlag -- | Make an 'IfaceForAllBndr' from an 'IfaceTvBndr'. mkIfaceForAllTvBndr :: ArgFlag -> IfaceTvBndr -> IfaceForAllBndr mkIfaceForAllTvBndr vis var = Bndr (IfaceTvBndr var) vis -- | Stores the arguments in a type application as a list. -- See @Note [Suppressing invisible arguments]@. data IfaceAppArgs = IA_Nil | IA_Arg IfaceType -- The type argument ArgFlag -- The argument's visibility. We store this here so -- that we can: -- -- 1. Avoid pretty-printing invisible (i.e., specified -- or inferred) arguments when -- -fprint-explicit-kinds isn't enabled, or -- 2. When -fprint-explicit-kinds *is*, enabled, print -- specified arguments in @(...) and inferred -- arguments in @{...}. IfaceAppArgs -- The rest of the arguments instance Semi.Semigroup IfaceAppArgs where IA_Nil <> xs = xs IA_Arg ty argf rest <> xs = IA_Arg ty argf (rest Semi.<> xs) instance Monoid IfaceAppArgs where mempty = IA_Nil mappend = (Semi.<>) -- Encodes type constructors, kind constructors, -- coercion constructors, the lot. -- We have to tag them in order to pretty print them -- properly. data IfaceTyCon = IfaceTyCon { ifaceTyConName :: IfExtName , ifaceTyConInfo :: IfaceTyConInfo } deriving (Eq) -- | The various types of TyCons which have special, built-in syntax. data IfaceTyConSort = IfaceNormalTyCon -- ^ a regular tycon | IfaceTupleTyCon !Arity !TupleSort -- ^ e.g. @(a, b, c)@ or @(#a, b, c#)@. -- The arity is the tuple width, not the tycon arity -- (which is twice the width in the case of unboxed -- tuples). | IfaceSumTyCon !Arity -- ^ e.g. @(a | b | c)@ | IfaceEqualityTyCon -- ^ A heterogeneous equality TyCon -- (i.e. eqPrimTyCon, eqReprPrimTyCon, heqTyCon) -- that is actually being applied to two types -- of the same kind. This affects pretty-printing -- only: see Note [Equality predicates in IfaceType] deriving (Eq) {- Note [Free tyvars in IfaceType] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Nowadays (since Nov 16, 2016) we pretty-print a Type by converting to an IfaceType and pretty printing that. This eliminates a lot of pretty-print duplication, and it matches what we do with pretty- printing TyThings. See Note [Pretty printing via IfaceSyn] in PprTyThing. It works fine for closed types, but when printing debug traces (e.g. when using -ddump-tc-trace) we print a lot of /open/ types. These types are full of TcTyVars, and it's absolutely crucial to print them in their full glory, with their unique, TcTyVarDetails etc. So we simply embed a TyVar in IfaceType with the IfaceFreeTyVar constructor. Note that: * We never expect to serialise an IfaceFreeTyVar into an interface file, nor to deserialise one. IfaceFreeTyVar is used only in the "convert to IfaceType and then pretty-print" pipeline. We do the same for covars, naturally. Note [Equality predicates in IfaceType] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ GHC has several varieties of type equality (see Note [The equality types story] in TysPrim for details). In an effort to avoid confusing users, we suppress the differences during pretty printing unless certain flags are enabled. Here is how each equality predicate* is printed in homogeneous and heterogeneous contexts, depending on which combination of the -fprint-explicit-kinds and -fprint-equality-relations flags is used: -------------------------------------------------------------------------------------------- | Predicate | Neither flag | -fprint-explicit-kinds | |-------------------------------|----------------------------|-----------------------------| | a ~ b (homogeneous) | a ~ b | (a :: Type) ~ (b :: Type) | | a ~~ b, homogeneously | a ~ b | (a :: Type) ~ (b :: Type) | | a ~~ b, heterogeneously | a ~~ c | (a :: Type) ~~ (c :: k) | | a ~# b, homogeneously | a ~ b | (a :: Type) ~ (b :: Type) | | a ~# b, heterogeneously | a ~~ c | (a :: Type) ~~ (c :: k) | | Coercible a b (homogeneous) | Coercible a b | Coercible @Type a b | | a ~R# b, homogeneously | Coercible a b | Coercible @Type a b | | a ~R# b, heterogeneously | a ~R# b | (a :: Type) ~R# (c :: k) | |-------------------------------|----------------------------|-----------------------------| | Predicate | -fprint-equality-relations | Both flags | |-------------------------------|----------------------------|-----------------------------| | a ~ b (homogeneous) | a ~ b | (a :: Type) ~ (b :: Type) | | a ~~ b, homogeneously | a ~~ b | (a :: Type) ~~ (b :: Type) | | a ~~ b, heterogeneously | a ~~ c | (a :: Type) ~~ (c :: k) | | a ~# b, homogeneously | a ~# b | (a :: Type) ~# (b :: Type) | | a ~# b, heterogeneously | a ~# c | (a :: Type) ~# (c :: k) | | Coercible a b (homogeneous) | Coercible a b | Coercible @Type a b | | a ~R# b, homogeneously | a ~R# b | (a :: Type) ~R# (b :: Type) | | a ~R# b, heterogeneously | a ~R# b | (a :: Type) ~R# (c :: k) | -------------------------------------------------------------------------------------------- (* There is no heterogeneous, representational, lifted equality counterpart to (~~). There could be, but there seems to be no use for it.) This table adheres to the following rules: A. With -fprint-equality-relations, print the true equality relation. B. Without -fprint-equality-relations: i. If the equality is representational and homogeneous, use Coercible. ii. Otherwise, if the equality is representational, use ~R#. iii. If the equality is nominal and homogeneous, use ~. iv. Otherwise, if the equality is nominal, use ~~. C. With -fprint-explicit-kinds, print kinds on both sides of an infix operator, as above; or print the kind with Coercible. D. Without -fprint-explicit-kinds, don't print kinds. A hetero-kinded equality is used homogeneously when it is applied to two identical kinds. Unfortunately, determining this from an IfaceType isn't possible since we can't see through type synonyms. Consequently, we need to record whether this particular application is homogeneous in IfaceTyConSort for the purposes of pretty-printing. See Note [The equality types story] in TysPrim. -} data IfaceTyConInfo -- Used to guide pretty-printing -- and to disambiguate D from 'D (they share a name) = IfaceTyConInfo { ifaceTyConIsPromoted :: PromotionFlag , ifaceTyConSort :: IfaceTyConSort } deriving (Eq) data IfaceMCoercion = IfaceMRefl | IfaceMCo IfaceCoercion data IfaceCoercion = IfaceReflCo IfaceType | IfaceGReflCo Role IfaceType (IfaceMCoercion) | IfaceFunCo Role IfaceCoercion IfaceCoercion | IfaceTyConAppCo Role IfaceTyCon [IfaceCoercion] | IfaceAppCo IfaceCoercion IfaceCoercion | IfaceForAllCo IfaceBndr IfaceCoercion IfaceCoercion | IfaceCoVarCo IfLclName | IfaceAxiomInstCo IfExtName BranchIndex [IfaceCoercion] | IfaceAxiomRuleCo IfLclName [IfaceCoercion] -- There are only a fixed number of CoAxiomRules, so it suffices -- to use an IfaceLclName to distinguish them. -- See Note [Adding built-in type families] in TcTypeNats | IfaceUnivCo IfaceUnivCoProv Role IfaceType IfaceType | IfaceSymCo IfaceCoercion | IfaceTransCo IfaceCoercion IfaceCoercion | IfaceNthCo Int IfaceCoercion | IfaceLRCo LeftOrRight IfaceCoercion | IfaceInstCo IfaceCoercion IfaceCoercion | IfaceKindCo IfaceCoercion | IfaceSubCo IfaceCoercion | IfaceFreeCoVar CoVar -- See Note [Free tyvars in IfaceType] | IfaceHoleCo CoVar -- ^ See Note [Holes in IfaceCoercion] data IfaceUnivCoProv = IfaceUnsafeCoerceProv | IfacePhantomProv IfaceCoercion | IfaceProofIrrelProv IfaceCoercion | IfacePluginProv String {- Note [Holes in IfaceCoercion] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ When typechecking fails the typechecker will produce a HoleCo to stand in place of the unproven assertion. While we generally don't want to let these unproven assertions leak into interface files, we still need to be able to pretty-print them as we use IfaceType's pretty-printer to render Types. For this reason IfaceCoercion has a IfaceHoleCo constructor; however, we fails when asked to serialize to a IfaceHoleCo to ensure that they don't end up in an interface file. %************************************************************************ %* * Functions over IFaceTypes * * ************************************************************************ -} ifaceTyConHasKey :: IfaceTyCon -> Unique -> Bool ifaceTyConHasKey tc key = ifaceTyConName tc `hasKey` key isIfaceLiftedTypeKind :: IfaceKind -> Bool isIfaceLiftedTypeKind (IfaceTyConApp tc IA_Nil) = isLiftedTypeKindTyConName (ifaceTyConName tc) isIfaceLiftedTypeKind (IfaceTyConApp tc (IA_Arg (IfaceTyConApp ptr_rep_lifted IA_Nil) Required IA_Nil)) = tc `ifaceTyConHasKey` tYPETyConKey && ptr_rep_lifted `ifaceTyConHasKey` liftedRepDataConKey isIfaceLiftedTypeKind _ = False splitIfaceSigmaTy :: IfaceType -> ([IfaceForAllBndr], [IfacePredType], IfaceType) -- Mainly for printing purposes -- -- Here we split nested IfaceSigmaTy properly. -- -- @ -- forall t. T t => forall m a b. M m => (a -> m b) -> t a -> m (t b) -- @ -- -- If you called @splitIfaceSigmaTy@ on this type: -- -- @ -- ([t, m, a, b], [T t, M m], (a -> m b) -> t a -> m (t b)) -- @ splitIfaceSigmaTy ty = case (bndrs, theta) of ([], []) -> (bndrs, theta, tau) _ -> let (bndrs', theta', tau') = splitIfaceSigmaTy tau in (bndrs ++ bndrs', theta ++ theta', tau') where (bndrs, rho) = split_foralls ty (theta, tau) = split_rho rho split_foralls (IfaceForAllTy bndr ty) = case split_foralls ty of { (bndrs, rho) -> (bndr:bndrs, rho) } split_foralls rho = ([], rho) split_rho (IfaceDFunTy ty1 ty2) = case split_rho ty2 of { (ps, tau) -> (ty1:ps, tau) } split_rho tau = ([], tau) suppressIfaceInvisibles :: DynFlags -> [IfaceTyConBinder] -> [a] -> [a] suppressIfaceInvisibles dflags tys xs | gopt Opt_PrintExplicitKinds dflags = xs | otherwise = suppress tys xs where suppress _ [] = [] suppress [] a = a suppress (k:ks) (x:xs) | isInvisibleTyConBinder k = suppress ks xs | otherwise = x : suppress ks xs stripIfaceInvisVars :: DynFlags -> [IfaceTyConBinder] -> [IfaceTyConBinder] stripIfaceInvisVars dflags tyvars | gopt Opt_PrintExplicitKinds dflags = tyvars | otherwise = filterOut isInvisibleTyConBinder tyvars -- | Extract an 'IfaceBndr' from an 'IfaceForAllBndr'. ifForAllBndrVar :: IfaceForAllBndr -> IfaceBndr ifForAllBndrVar = binderVar -- | Extract the variable name from an 'IfaceForAllBndr'. ifForAllBndrName :: IfaceForAllBndr -> IfLclName ifForAllBndrName fab = ifaceBndrName (ifForAllBndrVar fab) -- | Extract an 'IfaceBndr' from an 'IfaceTyConBinder'. ifTyConBinderVar :: IfaceTyConBinder -> IfaceBndr ifTyConBinderVar = binderVar -- | Extract the variable name from an 'IfaceTyConBinder'. ifTyConBinderName :: IfaceTyConBinder -> IfLclName ifTyConBinderName tcb = ifaceBndrName (ifTyConBinderVar tcb) ifTypeIsVarFree :: IfaceType -> Bool -- Returns True if the type definitely has no variables at all -- Just used to control pretty printing ifTypeIsVarFree ty = go ty where go (IfaceTyVar {}) = False go (IfaceFreeTyVar {}) = False go (IfaceAppTy fun args) = go fun && go_args args go (IfaceFunTy arg res) = go arg && go res go (IfaceDFunTy arg res) = go arg && go res go (IfaceForAllTy {}) = False go (IfaceTyConApp _ args) = go_args args go (IfaceTupleTy _ _ args) = go_args args go (IfaceLitTy _) = True go (IfaceCastTy {}) = False -- Safe go (IfaceCoercionTy {}) = False -- Safe go_args IA_Nil = True go_args (IA_Arg arg _ args) = go arg && go_args args {- Note [Substitution on IfaceType] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Substitutions on IfaceType are done only during pretty-printing to construct the result type of a GADT, and does not deal with binders (eg IfaceForAll), so it doesn't need fancy capture stuff. -} type IfaceTySubst = FastStringEnv IfaceType -- Note [Substitution on IfaceType] mkIfaceTySubst :: [(IfLclName,IfaceType)] -> IfaceTySubst -- See Note [Substitution on IfaceType] mkIfaceTySubst eq_spec = mkFsEnv eq_spec inDomIfaceTySubst :: IfaceTySubst -> IfaceTvBndr -> Bool -- See Note [Substitution on IfaceType] inDomIfaceTySubst subst (fs, _) = isJust (lookupFsEnv subst fs) substIfaceType :: IfaceTySubst -> IfaceType -> IfaceType -- See Note [Substitution on IfaceType] substIfaceType env ty = go ty where go (IfaceFreeTyVar tv) = IfaceFreeTyVar tv go (IfaceTyVar tv) = substIfaceTyVar env tv go (IfaceAppTy t ts) = IfaceAppTy (go t) (substIfaceAppArgs env ts) go (IfaceFunTy t1 t2) = IfaceFunTy (go t1) (go t2) go (IfaceDFunTy t1 t2) = IfaceDFunTy (go t1) (go t2) go ty@(IfaceLitTy {}) = ty go (IfaceTyConApp tc tys) = IfaceTyConApp tc (substIfaceAppArgs env tys) go (IfaceTupleTy s i tys) = IfaceTupleTy s i (substIfaceAppArgs env tys) go (IfaceForAllTy {}) = pprPanic "substIfaceType" (ppr ty) go (IfaceCastTy ty co) = IfaceCastTy (go ty) (go_co co) go (IfaceCoercionTy co) = IfaceCoercionTy (go_co co) go_mco IfaceMRefl = IfaceMRefl go_mco (IfaceMCo co) = IfaceMCo $ go_co co go_co (IfaceReflCo ty) = IfaceReflCo (go ty) go_co (IfaceGReflCo r ty mco) = IfaceGReflCo r (go ty) (go_mco mco) go_co (IfaceFunCo r c1 c2) = IfaceFunCo r (go_co c1) (go_co c2) go_co (IfaceTyConAppCo r tc cos) = IfaceTyConAppCo r tc (go_cos cos) go_co (IfaceAppCo c1 c2) = IfaceAppCo (go_co c1) (go_co c2) go_co (IfaceForAllCo {}) = pprPanic "substIfaceCoercion" (ppr ty) go_co (IfaceFreeCoVar cv) = IfaceFreeCoVar cv go_co (IfaceCoVarCo cv) = IfaceCoVarCo cv go_co (IfaceHoleCo cv) = IfaceHoleCo cv go_co (IfaceAxiomInstCo a i cos) = IfaceAxiomInstCo a i (go_cos cos) go_co (IfaceUnivCo prov r t1 t2) = IfaceUnivCo (go_prov prov) r (go t1) (go t2) go_co (IfaceSymCo co) = IfaceSymCo (go_co co) go_co (IfaceTransCo co1 co2) = IfaceTransCo (go_co co1) (go_co co2) go_co (IfaceNthCo n co) = IfaceNthCo n (go_co co) go_co (IfaceLRCo lr co) = IfaceLRCo lr (go_co co) go_co (IfaceInstCo c1 c2) = IfaceInstCo (go_co c1) (go_co c2) go_co (IfaceKindCo co) = IfaceKindCo (go_co co) go_co (IfaceSubCo co) = IfaceSubCo (go_co co) go_co (IfaceAxiomRuleCo n cos) = IfaceAxiomRuleCo n (go_cos cos) go_cos = map go_co go_prov IfaceUnsafeCoerceProv = IfaceUnsafeCoerceProv go_prov (IfacePhantomProv co) = IfacePhantomProv (go_co co) go_prov (IfaceProofIrrelProv co) = IfaceProofIrrelProv (go_co co) go_prov (IfacePluginProv str) = IfacePluginProv str substIfaceAppArgs :: IfaceTySubst -> IfaceAppArgs -> IfaceAppArgs substIfaceAppArgs env args = go args where go IA_Nil = IA_Nil go (IA_Arg ty arg tys) = IA_Arg (substIfaceType env ty) arg (go tys) substIfaceTyVar :: IfaceTySubst -> IfLclName -> IfaceType substIfaceTyVar env tv | Just ty <- lookupFsEnv env tv = ty | otherwise = IfaceTyVar tv {- ************************************************************************ * * Functions over IfaceAppArgs * * ************************************************************************ -} stripInvisArgs :: DynFlags -> IfaceAppArgs -> IfaceAppArgs stripInvisArgs dflags tys | gopt Opt_PrintExplicitKinds dflags = tys | otherwise = suppress_invis tys where suppress_invis c = case c of IA_Nil -> IA_Nil IA_Arg t argf ts | isVisibleArgFlag argf -> IA_Arg t argf $ suppress_invis ts -- Keep recursing through the remainder of the arguments, as it's -- possible that there are remaining invisible ones. -- See the "In type declarations" section of Note [VarBndrs, -- TyCoVarBinders, TyConBinders, and visibility] in TyCoRep. | otherwise -> suppress_invis ts appArgsIfaceTypes :: IfaceAppArgs -> [IfaceType] appArgsIfaceTypes IA_Nil = [] appArgsIfaceTypes (IA_Arg t _ ts) = t : appArgsIfaceTypes ts appArgsIfaceTypesArgFlags :: IfaceAppArgs -> [(IfaceType, ArgFlag)] appArgsIfaceTypesArgFlags IA_Nil = [] appArgsIfaceTypesArgFlags (IA_Arg t a ts) = (t, a) : appArgsIfaceTypesArgFlags ts ifaceVisAppArgsLength :: IfaceAppArgs -> Int ifaceVisAppArgsLength = go 0 where go !n IA_Nil = n go n (IA_Arg _ argf rest) | isVisibleArgFlag argf = go (n+1) rest | otherwise = go n rest {- Note [Suppressing invisible arguments] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ We use the IfaceAppArgs data type to specify which of the arguments to a type should be displayed when pretty-printing, under the control of -fprint-explicit-kinds. See also Type.filterOutInvisibleTypes. For example, given T :: forall k. (k->*) -> k -> * -- Ordinary kind polymorphism 'Just :: forall k. k -> 'Maybe k -- Promoted we want T * Tree Int prints as T Tree Int 'Just * prints as Just * For type constructors (IfaceTyConApp), IfaceAppArgs is a quite natural fit, since the corresponding Core constructor: data Type = ... | TyConApp TyCon [Type] Already puts all of its arguments into a list. So when converting a Type to an IfaceType (see toIfaceAppArgsX in ToIface), we simply use the kind of the TyCon (which is cached) to guide the process of converting the argument Types into an IfaceAppArgs list. We also want this behavior for IfaceAppTy, since given: data Proxy (a :: k) f :: forall (t :: forall a. a -> Type). Proxy Type (t Bool True) We want to print the return type as `Proxy (t True)` without the use of -fprint-explicit-kinds (#15330). Accomplishing this is trickier than in the tycon case, because the corresponding Core constructor for IfaceAppTy: data Type = ... | AppTy Type Type Only stores one argument at a time. Therefore, when converting an AppTy to an IfaceAppTy (in toIfaceTypeX in ToIface), we: 1. Flatten the chain of AppTys down as much as possible 2. Use typeKind to determine the function Type's kind 3. Use this kind to guide the process of converting the argument Types into an IfaceAppArgs list. By flattening the arguments like this, we obtain two benefits: (a) We can reuse the same machinery to pretty-print IfaceTyConApp arguments as we do IfaceTyApp arguments, which means that we only need to implement the logic to filter out invisible arguments once. (b) Unlike for tycons, finding the kind of a type in general (through typeKind) is not a constant-time operation, so by flattening the arguments first, we decrease the number of times we have to call typeKind. Note [Pretty-printing invisible arguments] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Note [Suppressing invisible arguments] is all about how to avoid printing invisible arguments when the -fprint-explicit-kinds flag is disables. Well, what about when it's enabled? Then we can and should print invisible kind arguments, and this Note explains how we do it. As two running examples, consider the following code: {-# LANGUAGE PolyKinds #-} data T1 a data T2 (a :: k) When displaying these types (with -fprint-explicit-kinds on), we could just do the following: T1 k a T2 k a That certainly gets the job done. But it lacks a crucial piece of information: is the `k` argument inferred or specified? To communicate this, we use visible kind application syntax to distinguish the two cases: T1 @{k} a T2 @k a Here, @{k} indicates that `k` is an inferred argument, and @k indicates that `k` is a specified argument. (See Note [VarBndrs, TyCoVarBinders, TyConBinders, and visibility] in TyCoRep for a lengthier explanation on what "inferred" and "specified" mean.) ************************************************************************ * * Pretty-printing * * ************************************************************************ -} if_print_coercions :: SDoc -- ^ if printing coercions -> SDoc -- ^ otherwise -> SDoc if_print_coercions yes no = sdocWithDynFlags $ \dflags -> getPprStyle $ \style -> if gopt Opt_PrintExplicitCoercions dflags || dumpStyle style || debugStyle style then yes else no pprIfaceInfixApp :: PprPrec -> SDoc -> SDoc -> SDoc -> SDoc pprIfaceInfixApp ctxt_prec pp_tc pp_ty1 pp_ty2 = maybeParen ctxt_prec opPrec $ sep [pp_ty1, pp_tc <+> pp_ty2] pprIfacePrefixApp :: PprPrec -> SDoc -> [SDoc] -> SDoc pprIfacePrefixApp ctxt_prec pp_fun pp_tys | null pp_tys = pp_fun | otherwise = maybeParen ctxt_prec appPrec $ hang pp_fun 2 (sep pp_tys) -- ----------------------------- Printing binders ------------------------------------ instance Outputable IfaceBndr where ppr (IfaceIdBndr bndr) = pprIfaceIdBndr bndr ppr (IfaceTvBndr bndr) = char '@' <+> pprIfaceTvBndr False bndr pprIfaceBndrs :: [IfaceBndr] -> SDoc pprIfaceBndrs bs = sep (map ppr bs) pprIfaceLamBndr :: IfaceLamBndr -> SDoc pprIfaceLamBndr (b, IfaceNoOneShot) = ppr b pprIfaceLamBndr (b, IfaceOneShot) = ppr b <> text "[OneShot]" pprIfaceIdBndr :: IfaceIdBndr -> SDoc pprIfaceIdBndr (name, ty) = parens (ppr name <+> dcolon <+> ppr ty) pprIfaceTvBndr :: Bool -> IfaceTvBndr -> SDoc pprIfaceTvBndr use_parens (tv, ki) | isIfaceLiftedTypeKind ki = ppr tv | otherwise = maybe_parens (ppr tv <+> dcolon <+> ppr ki) where maybe_parens | use_parens = parens | otherwise = id pprIfaceTyConBinders :: [IfaceTyConBinder] -> SDoc pprIfaceTyConBinders = sep . map go where go :: IfaceTyConBinder -> SDoc go (Bndr (IfaceIdBndr bndr) _) = pprIfaceIdBndr bndr go (Bndr (IfaceTvBndr bndr) vis) = -- See Note [Pretty-printing invisible arguments] case vis of AnonTCB -> ppr_bndr True NamedTCB Required -> ppr_bndr True NamedTCB Specified -> char '@' <> ppr_bndr True NamedTCB Inferred -> char '@' <> braces (ppr_bndr False) where ppr_bndr use_parens = pprIfaceTvBndr use_parens bndr instance Binary IfaceBndr where put_ bh (IfaceIdBndr aa) = do putByte bh 0 put_ bh aa put_ bh (IfaceTvBndr ab) = do putByte bh 1 put_ bh ab get bh = do h <- getByte bh case h of 0 -> do aa <- get bh return (IfaceIdBndr aa) _ -> do ab <- get bh return (IfaceTvBndr ab) instance Binary IfaceOneShot where put_ bh IfaceNoOneShot = do putByte bh 0 put_ bh IfaceOneShot = do putByte bh 1 get bh = do h <- getByte bh case h of 0 -> do return IfaceNoOneShot _ -> do return IfaceOneShot -- ----------------------------- Printing IfaceType ------------------------------------ --------------------------------- instance Outputable IfaceType where ppr ty = pprIfaceType ty pprIfaceType, pprParendIfaceType :: IfaceType -> SDoc pprIfaceType = pprPrecIfaceType topPrec pprParendIfaceType = pprPrecIfaceType appPrec pprPrecIfaceType :: PprPrec -> IfaceType -> SDoc -- We still need `eliminateRuntimeRep`, since the `pprPrecIfaceType` maybe -- called from other places, besides `:type` and `:info`. pprPrecIfaceType prec ty = eliminateRuntimeRep (ppr_ty prec) ty ppr_ty :: PprPrec -> IfaceType -> SDoc ppr_ty _ (IfaceFreeTyVar tyvar) = ppr tyvar -- This is the main reason for IfaceFreeTyVar! ppr_ty _ (IfaceTyVar tyvar) = ppr tyvar -- See Note [TcTyVars in IfaceType] ppr_ty ctxt_prec (IfaceTyConApp tc tys) = pprTyTcApp ctxt_prec tc tys ppr_ty ctxt_prec (IfaceTupleTy i p tys) = pprTuple ctxt_prec i p tys ppr_ty _ (IfaceLitTy n) = pprIfaceTyLit n -- Function types ppr_ty ctxt_prec (IfaceFunTy ty1 ty2) = -- We don't want to lose synonyms, so we mustn't use splitFunTys here. maybeParen ctxt_prec funPrec $ sep [ppr_ty funPrec ty1, sep (ppr_fun_tail ty2)] where ppr_fun_tail (IfaceFunTy ty1 ty2) = (arrow <+> ppr_ty funPrec ty1) : ppr_fun_tail ty2 ppr_fun_tail other_ty = [arrow <+> pprIfaceType other_ty] ppr_ty ctxt_prec (IfaceAppTy t ts) = if_print_coercions ppr_app_ty ppr_app_ty_no_casts where ppr_app_ty = sdocWithDynFlags $ \dflags -> pprIfacePrefixApp ctxt_prec (ppr_ty funPrec t) (map (ppr_app_arg appPrec) (tys_wo_kinds dflags)) tys_wo_kinds dflags = appArgsIfaceTypesArgFlags $ stripInvisArgs dflags ts -- Strip any casts from the head of the application ppr_app_ty_no_casts = case t of IfaceCastTy head _ -> ppr_ty ctxt_prec (mk_app_tys head ts) _ -> ppr_app_ty mk_app_tys :: IfaceType -> IfaceAppArgs -> IfaceType mk_app_tys (IfaceTyConApp tc tys1) tys2 = IfaceTyConApp tc (tys1 `mappend` tys2) mk_app_tys t1 tys2 = IfaceAppTy t1 tys2 ppr_ty ctxt_prec (IfaceCastTy ty co) = if_print_coercions (parens (ppr_ty topPrec ty <+> text "|>" <+> ppr co)) (ppr_ty ctxt_prec ty) ppr_ty ctxt_prec (IfaceCoercionTy co) = if_print_coercions (ppr_co ctxt_prec co) (text "<>") ppr_ty ctxt_prec ty -- IfaceForAllTy = maybeParen ctxt_prec funPrec (pprIfaceSigmaType ShowForAllMust ty) {- Note [Defaulting RuntimeRep variables] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ RuntimeRep variables are considered by many (most?) users to be little more than syntactic noise. When the notion was introduced there was a signficant and understandable push-back from those with pedagogy in mind, which argued that RuntimeRep variables would throw a wrench into nearly any teach approach since they appear in even the lowly ($) function's type, ($) :: forall (w :: RuntimeRep) a (b :: TYPE w). (a -> b) -> a -> b which is significantly less readable than its non RuntimeRep-polymorphic type of ($) :: (a -> b) -> a -> b Moreover, unboxed types don't appear all that often in run-of-the-mill Haskell programs, so it makes little sense to make all users pay this syntactic overhead. For this reason it was decided that we would hide RuntimeRep variables for now (see #11549). We do this by defaulting all type variables of kind RuntimeRep to LiftedRep. This is done in a pass right before pretty-printing (defaultRuntimeRepVars, controlled by -fprint-explicit-runtime-reps) This applies to /quantified/ variables like 'w' above. What about variables that are /free/ in the type being printed, which certainly happens in error messages. Suppose (Trac #16074) we are reporting a mismatch between two skolems (a :: RuntimeRep) ~ (b :: RuntimeRep) We certainly don't want to say "Can't match LiftedRep ~ LiftedRep"! But if we are printing the type (forall (a :: Type r). blah we do want to turn that (free) r into LiftedRep, so it prints as (forall a. blah) Conclusion: keep track of whether we we are in the kind of a binder; ohly if so, convert free RuntimeRep variables to LiftedRep. -} -- | Default 'RuntimeRep' variables to 'LiftedPtr'. e.g. -- -- @ -- ($) :: forall (r :: GHC.Types.RuntimeRep) a (b :: TYPE r). -- (a -> b) -> a -> b -- @ -- -- turns in to, -- -- @ ($) :: forall a (b :: *). (a -> b) -> a -> b @ -- -- We do this to prevent RuntimeRep variables from incurring a significant -- syntactic overhead in otherwise simple type signatures (e.g. ($)). See -- Note [Defaulting RuntimeRep variables] and #11549 for further discussion. -- defaultRuntimeRepVars :: IfaceType -> IfaceType defaultRuntimeRepVars ty = go False emptyFsEnv ty where go :: Bool -- True <=> Inside the kind of a binder -> FastStringEnv () -- Set of enclosing forall-ed RuntimeRep variables -> IfaceType -- (replace them with LiftedRep) -> IfaceType go ink subs (IfaceForAllTy (Bndr (IfaceTvBndr (var, var_kind)) argf) ty) | isRuntimeRep var_kind , isInvisibleArgFlag argf -- Don't default *visible* quantification -- or we get the mess in #13963 = let subs' = extendFsEnv subs var () -- Record that we should replace it with LiftedRep, -- and recurse, discarding the forall in go ink subs' ty go ink subs (IfaceForAllTy bndr ty) = IfaceForAllTy (go_ifacebndr subs bndr) (go ink subs ty) go _ subs ty@(IfaceTyVar tv) | tv `elemFsEnv` subs = IfaceTyConApp liftedRep IA_Nil | otherwise = ty go in_kind _ ty@(IfaceFreeTyVar tv) -- See Note [Defaulting RuntimeRep variables], about free vars | in_kind && TyCoRep.isRuntimeRepTy (tyVarKind tv) = IfaceTyConApp liftedRep IA_Nil | otherwise = ty go ink subs (IfaceTyConApp tc tc_args) = IfaceTyConApp tc (go_args ink subs tc_args) go ink subs (IfaceTupleTy sort is_prom tc_args) = IfaceTupleTy sort is_prom (go_args ink subs tc_args) go ink subs (IfaceFunTy arg res) = IfaceFunTy (go ink subs arg) (go ink subs res) go ink subs (IfaceAppTy t ts) = IfaceAppTy (go ink subs t) (go_args ink subs ts) go ink subs (IfaceDFunTy x y) = IfaceDFunTy (go ink subs x) (go ink subs y) go ink subs (IfaceCastTy x co) = IfaceCastTy (go ink subs x) co go _ _ ty@(IfaceLitTy {}) = ty go _ _ ty@(IfaceCoercionTy {}) = ty go_ifacebndr :: FastStringEnv () -> IfaceForAllBndr -> IfaceForAllBndr go_ifacebndr subs (Bndr (IfaceIdBndr (n, t)) argf) = Bndr (IfaceIdBndr (n, go True subs t)) argf go_ifacebndr subs (Bndr (IfaceTvBndr (n, t)) argf) = Bndr (IfaceTvBndr (n, go True subs t)) argf go_args :: Bool -> FastStringEnv () -> IfaceAppArgs -> IfaceAppArgs go_args _ _ IA_Nil = IA_Nil go_args ink subs (IA_Arg ty argf args) = IA_Arg (go ink subs ty) argf (go_args ink subs args) liftedRep :: IfaceTyCon liftedRep = IfaceTyCon dc_name (IfaceTyConInfo IsPromoted IfaceNormalTyCon) where dc_name = getName liftedRepDataConTyCon isRuntimeRep :: IfaceType -> Bool isRuntimeRep (IfaceTyConApp tc _) = tc `ifaceTyConHasKey` runtimeRepTyConKey isRuntimeRep _ = False eliminateRuntimeRep :: (IfaceType -> SDoc) -> IfaceType -> SDoc eliminateRuntimeRep f ty = sdocWithDynFlags $ \dflags -> getPprStyle $ \sty -> if userStyle sty && not (gopt Opt_PrintExplicitRuntimeReps dflags) then f (defaultRuntimeRepVars ty) else f ty instance Outputable IfaceAppArgs where ppr tca = pprIfaceAppArgs tca pprIfaceAppArgs, pprParendIfaceAppArgs :: IfaceAppArgs -> SDoc pprIfaceAppArgs = ppr_app_args topPrec pprParendIfaceAppArgs = ppr_app_args appPrec ppr_app_args :: PprPrec -> IfaceAppArgs -> SDoc ppr_app_args ctx_prec = go where go :: IfaceAppArgs -> SDoc go IA_Nil = empty go (IA_Arg t argf ts) = ppr_app_arg ctx_prec (t, argf) <+> go ts -- See Note [Pretty-printing invisible arguments] ppr_app_arg :: PprPrec -> (IfaceType, ArgFlag) -> SDoc ppr_app_arg ctx_prec (t, argf) = sdocWithDynFlags $ \dflags -> let print_kinds = gopt Opt_PrintExplicitKinds dflags in case argf of Required -> ppr_ty ctx_prec t Specified | print_kinds -> char '@' <> ppr_ty appPrec t Inferred | print_kinds -> char '@' <> braces (ppr_ty topPrec t) _ -> empty ------------------- pprIfaceForAllPart :: [IfaceForAllBndr] -> [IfacePredType] -> SDoc -> SDoc pprIfaceForAllPart tvs ctxt sdoc = ppr_iface_forall_part ShowForAllWhen tvs ctxt sdoc -- | Like 'pprIfaceForAllPart', but always uses an explicit @forall@. pprIfaceForAllPartMust :: [IfaceForAllBndr] -> [IfacePredType] -> SDoc -> SDoc pprIfaceForAllPartMust tvs ctxt sdoc = ppr_iface_forall_part ShowForAllMust tvs ctxt sdoc pprIfaceForAllCoPart :: [(IfLclName, IfaceCoercion)] -> SDoc -> SDoc pprIfaceForAllCoPart tvs sdoc = sep [ pprIfaceForAllCo tvs, sdoc ] ppr_iface_forall_part :: ShowForAllFlag -> [IfaceForAllBndr] -> [IfacePredType] -> SDoc -> SDoc ppr_iface_forall_part show_forall tvs ctxt sdoc = sep [ case show_forall of ShowForAllMust -> pprIfaceForAll tvs ShowForAllWhen -> pprUserIfaceForAll tvs , pprIfaceContextArr ctxt , sdoc] -- | Render the "forall ... ." or "forall ... ->" bit of a type. pprIfaceForAll :: [IfaceForAllBndr] -> SDoc pprIfaceForAll [] = empty pprIfaceForAll bndrs@(Bndr _ vis : _) = sep [ add_separator (forAllLit <+> fsep docs) , pprIfaceForAll bndrs' ] where (bndrs', docs) = ppr_itv_bndrs bndrs vis add_separator stuff = case vis of Required -> stuff <+> arrow _inv -> stuff <> dot -- | Render the ... in @(forall ... .)@ or @(forall ... ->)@. -- Returns both the list of not-yet-rendered binders and the doc. -- No anonymous binders here! ppr_itv_bndrs :: [IfaceForAllBndr] -> ArgFlag -- ^ visibility of the first binder in the list -> ([IfaceForAllBndr], [SDoc]) ppr_itv_bndrs all_bndrs@(bndr@(Bndr _ vis) : bndrs) vis1 | vis `sameVis` vis1 = let (bndrs', doc) = ppr_itv_bndrs bndrs vis1 in (bndrs', pprIfaceForAllBndr bndr : doc) | otherwise = (all_bndrs, []) ppr_itv_bndrs [] _ = ([], []) pprIfaceForAllCo :: [(IfLclName, IfaceCoercion)] -> SDoc pprIfaceForAllCo [] = empty pprIfaceForAllCo tvs = text "forall" <+> pprIfaceForAllCoBndrs tvs <> dot pprIfaceForAllCoBndrs :: [(IfLclName, IfaceCoercion)] -> SDoc pprIfaceForAllCoBndrs bndrs = hsep $ map pprIfaceForAllCoBndr bndrs pprIfaceForAllBndr :: IfaceForAllBndr -> SDoc pprIfaceForAllBndr (Bndr (IfaceTvBndr tv) Inferred) = sdocWithDynFlags $ \dflags -> if gopt Opt_PrintExplicitForalls dflags then braces $ pprIfaceTvBndr False tv else pprIfaceTvBndr True tv pprIfaceForAllBndr (Bndr (IfaceTvBndr tv) _) = pprIfaceTvBndr True tv pprIfaceForAllBndr (Bndr (IfaceIdBndr idv) _) = pprIfaceIdBndr idv pprIfaceForAllCoBndr :: (IfLclName, IfaceCoercion) -> SDoc pprIfaceForAllCoBndr (tv, kind_co) = parens (ppr tv <+> dcolon <+> pprIfaceCoercion kind_co) -- | Show forall flag -- -- Unconditionally show the forall quantifier with ('ShowForAllMust') -- or when ('ShowForAllWhen') the names used are free in the binder -- or when compiling with -fprint-explicit-foralls. data ShowForAllFlag = ShowForAllMust | ShowForAllWhen pprIfaceSigmaType :: ShowForAllFlag -> IfaceType -> SDoc pprIfaceSigmaType show_forall ty = eliminateRuntimeRep ppr_fn ty where ppr_fn iface_ty = let (tvs, theta, tau) = splitIfaceSigmaTy iface_ty in ppr_iface_forall_part show_forall tvs theta (ppr tau) pprUserIfaceForAll :: [IfaceForAllBndr] -> SDoc pprUserIfaceForAll tvs = sdocWithDynFlags $ \dflags -> -- See Note [When to print foralls] ppWhen (any tv_has_kind_var tvs || any tv_is_required tvs || gopt Opt_PrintExplicitForalls dflags) $ pprIfaceForAll tvs where tv_has_kind_var (Bndr (IfaceTvBndr (_,kind)) _) = not (ifTypeIsVarFree kind) tv_has_kind_var _ = False tv_is_required = isVisibleArgFlag . binderArgFlag {- Note [When to print foralls] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~ We opt to explicitly pretty-print `forall`s if any of the following criteria are met: 1. -fprint-explicit-foralls is on. 2. A bound type variable has a polymorphic kind. E.g., forall k (a::k). Proxy a -> Proxy a Since a's kind mentions a variable k, we print the foralls. 3. A bound type variable is a visible argument (#14238). Suppose we are printing the kind of: T :: forall k -> k -> Type The "forall k ->" notation means that this kind argument is required. That is, it must be supplied at uses of T. E.g., f :: T (Type->Type) Monad -> Int So we print an explicit "T :: forall k -> k -> Type", because omitting it and printing "T :: k -> Type" would be utterly misleading. See Note [VarBndrs, TyCoVarBinders, TyConBinders, and visibility] in TyCoRep. N.B. Until now (Aug 2018) we didn't check anything for coercion variables. Note [Printing foralls in type family instances] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ We use the same criteria as in Note [When to print foralls] to determine whether a type family instance should be pretty-printed with an explicit `forall`. Example: type family Foo (a :: k) :: k where Foo Maybe = [] Foo (a :: Type) = Int Foo a = a Without -fprint-explicit-foralls enabled, this will be pretty-printed as: type family Foo (a :: k) :: k where Foo Maybe = [] Foo a = Int forall k (a :: k). Foo a = a Note that only the third equation has an explicit forall, since it has a type variable with a non-Type kind. (If -fprint-explicit-foralls were enabled, then the second equation would be preceded with `forall a.`.) There is one tricky point in the implementation: what visibility do we give the type variables in a type family instance? Type family instances only store type *variables*, not type variable *binders*, and only the latter has visibility information. We opt to default the visibility of each of these type variables to Specified because users can't ever instantiate these variables manually, so the choice of visibility is only relevant to pretty-printing. (This is why the `k` in `forall k (a :: k). ...` above is printed the way it is, even though it wasn't written explicitly in the original source code.) We adopt the same strategy for data family instances. Example: data family DF (a :: k) data instance DF '[a, b] = DFList That data family instance is pretty-printed as: data instance forall j (a :: j) (b :: j). DF '[a, b] = DFList This is despite that the representation tycon for this data instance (call it $DF:List) actually has different visibilities for its binders. However, the visibilities of these binders are utterly irrelevant to the programmer, who cares only about the specificity of variables in `DF`'s type, not $DF:List's type. Therefore, we opt to pretty-print all variables in data family instances as Specified. Note [Printing promoted type constructors] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Consider this GHCi session (Trac #14343) > _ :: Proxy '[ 'True ] error: Found hole: _ :: Proxy '['True] This would be bad, because the '[' looks like a character literal. Solution: in type-level lists and tuples, add a leading space if the first type is itself promoted. See pprSpaceIfPromotedTyCon. -} ------------------- -- | Prefix a space if the given 'IfaceType' is a promoted 'TyCon'. -- See Note [Printing promoted type constructors] pprSpaceIfPromotedTyCon :: IfaceType -> SDoc -> SDoc pprSpaceIfPromotedTyCon (IfaceTyConApp tyCon _) = case ifaceTyConIsPromoted (ifaceTyConInfo tyCon) of IsPromoted -> (space <>) _ -> id pprSpaceIfPromotedTyCon _ = id -- See equivalent function in TyCoRep.hs pprIfaceTyList :: PprPrec -> IfaceType -> IfaceType -> SDoc -- Given a type-level list (t1 ': t2), see if we can print -- it in list notation [t1, ...]. -- Precondition: Opt_PrintExplicitKinds is off pprIfaceTyList ctxt_prec ty1 ty2 = case gather ty2 of (arg_tys, Nothing) -> char '\'' <> brackets (pprSpaceIfPromotedTyCon ty1 (fsep (punctuate comma (map (ppr_ty topPrec) (ty1:arg_tys))))) (arg_tys, Just tl) -> maybeParen ctxt_prec funPrec $ hang (ppr_ty funPrec ty1) 2 (fsep [ colon <+> ppr_ty funPrec ty | ty <- arg_tys ++ [tl]]) where gather :: IfaceType -> ([IfaceType], Maybe IfaceType) -- (gather ty) = (tys, Nothing) means ty is a list [t1, .., tn] -- = (tys, Just tl) means ty is of form t1:t2:...tn:tl gather (IfaceTyConApp tc tys) | tc `ifaceTyConHasKey` consDataConKey , IA_Arg _ argf (IA_Arg ty1 Required (IA_Arg ty2 Required IA_Nil)) <- tys , isInvisibleArgFlag argf , (args, tl) <- gather ty2 = (ty1:args, tl) | tc `ifaceTyConHasKey` nilDataConKey = ([], Nothing) gather ty = ([], Just ty) pprIfaceTypeApp :: PprPrec -> IfaceTyCon -> IfaceAppArgs -> SDoc pprIfaceTypeApp prec tc args = pprTyTcApp prec tc args pprTyTcApp :: PprPrec -> IfaceTyCon -> IfaceAppArgs -> SDoc pprTyTcApp ctxt_prec tc tys = sdocWithDynFlags $ \dflags -> getPprStyle $ \style -> pprTyTcApp' ctxt_prec tc tys dflags style pprTyTcApp' :: PprPrec -> IfaceTyCon -> IfaceAppArgs -> DynFlags -> PprStyle -> SDoc pprTyTcApp' ctxt_prec tc tys dflags style | ifaceTyConName tc `hasKey` ipClassKey , IA_Arg (IfaceLitTy (IfaceStrTyLit n)) Required (IA_Arg ty Required IA_Nil) <- tys = maybeParen ctxt_prec funPrec $ char '?' <> ftext n <> text "::" <> ppr_ty topPrec ty | IfaceTupleTyCon arity sort <- ifaceTyConSort info , not (debugStyle style) , arity == ifaceVisAppArgsLength tys = pprTuple ctxt_prec sort (ifaceTyConIsPromoted info) tys | IfaceSumTyCon arity <- ifaceTyConSort info = pprSum arity (ifaceTyConIsPromoted info) tys | tc `ifaceTyConHasKey` consDataConKey , not (gopt Opt_PrintExplicitKinds dflags) , IA_Arg _ argf (IA_Arg ty1 Required (IA_Arg ty2 Required IA_Nil)) <- tys , isInvisibleArgFlag argf = pprIfaceTyList ctxt_prec ty1 ty2 | tc `ifaceTyConHasKey` tYPETyConKey , IA_Arg (IfaceTyConApp rep IA_Nil) Required IA_Nil <- tys , rep `ifaceTyConHasKey` liftedRepDataConKey = kindType | otherwise = getPprDebug $ \dbg -> if | not dbg && tc `ifaceTyConHasKey` errorMessageTypeErrorFamKey -- Suppress detail unles you _really_ want to see -> text "(TypeError ...)" | Just doc <- ppr_equality ctxt_prec tc (appArgsIfaceTypes tys) -> doc | otherwise -> ppr_iface_tc_app ppr_app_arg ctxt_prec tc tys_wo_kinds where info = ifaceTyConInfo tc tys_wo_kinds = appArgsIfaceTypesArgFlags $ stripInvisArgs dflags tys -- | Pretty-print a type-level equality. -- Returns (Just doc) if the argument is a /saturated/ application -- of eqTyCon (~) -- eqPrimTyCon (~#) -- eqReprPrimTyCon (~R#) -- heqTyCon (~~) -- -- See Note [Equality predicates in IfaceType] -- and Note [The equality types story] in TysPrim ppr_equality :: PprPrec -> IfaceTyCon -> [IfaceType] -> Maybe SDoc ppr_equality ctxt_prec tc args | hetero_eq_tc , [k1, k2, t1, t2] <- args = Just $ print_equality (k1, k2, t1, t2) | hom_eq_tc , [k, t1, t2] <- args = Just $ print_equality (k, k, t1, t2) | otherwise = Nothing where homogeneous = tc_name `hasKey` eqTyConKey -- (~) || hetero_tc_used_homogeneously where hetero_tc_used_homogeneously = case ifaceTyConSort $ ifaceTyConInfo tc of IfaceEqualityTyCon -> True _other -> False -- True <=> a heterogeneous equality whose arguments -- are (in this case) of the same kind tc_name = ifaceTyConName tc pp = ppr_ty hom_eq_tc = tc_name `hasKey` eqTyConKey -- (~) hetero_eq_tc = tc_name `hasKey` eqPrimTyConKey -- (~#) || tc_name `hasKey` eqReprPrimTyConKey -- (~R#) || tc_name `hasKey` heqTyConKey -- (~~) nominal_eq_tc = tc_name `hasKey` heqTyConKey -- (~~) || tc_name `hasKey` eqPrimTyConKey -- (~#) print_equality args = sdocWithDynFlags $ \dflags -> getPprStyle $ \style -> print_equality' args style dflags print_equality' (ki1, ki2, ty1, ty2) style dflags | -- If -fprint-equality-relations is on, just print the original TyCon print_eqs = ppr_infix_eq (ppr tc) | -- Homogeneous use of heterogeneous equality (ty1 ~~ ty2) -- or unlifted equality (ty1 ~# ty2) nominal_eq_tc, homogeneous = ppr_infix_eq (text "~") | -- Heterogeneous use of unlifted equality (ty1 ~# ty2) not homogeneous = ppr_infix_eq (ppr heqTyCon) | -- Homogeneous use of representational unlifted equality (ty1 ~R# ty2) tc_name `hasKey` eqReprPrimTyConKey, homogeneous = let ki | print_kinds = [pp appPrec ki1] | otherwise = [] in pprIfacePrefixApp ctxt_prec (ppr coercibleTyCon) (ki ++ [pp appPrec ty1, pp appPrec ty2]) -- The other cases work as you'd expect | otherwise = ppr_infix_eq (ppr tc) where ppr_infix_eq :: SDoc -> SDoc ppr_infix_eq eq_op = pprIfaceInfixApp ctxt_prec eq_op (pp_ty_ki ty1 ki1) (pp_ty_ki ty2 ki2) where pp_ty_ki ty ki | print_kinds = parens (pp topPrec ty <+> dcolon <+> pp opPrec ki) | otherwise = pp opPrec ty print_kinds = gopt Opt_PrintExplicitKinds dflags print_eqs = gopt Opt_PrintEqualityRelations dflags || dumpStyle style || debugStyle style pprIfaceCoTcApp :: PprPrec -> IfaceTyCon -> [IfaceCoercion] -> SDoc pprIfaceCoTcApp ctxt_prec tc tys = ppr_iface_tc_app (\prec (co, _) -> ppr_co prec co) ctxt_prec tc (map (, Required) tys) -- We are trying to re-use ppr_iface_tc_app here, which requires its -- arguments to be accompanied by visibilities. But visibility is -- irrelevant when printing coercions, so just default everything to -- Required. -- | Pretty-prints an application of a type constructor to some arguments -- (whose visibilities are known). This is polymorphic (over @a@) since we use -- this function to pretty-print two different things: -- -- 1. Types (from `pprTyTcApp'`) -- -- 2. Coercions (from 'pprIfaceCoTcApp') ppr_iface_tc_app :: (PprPrec -> (a, ArgFlag) -> SDoc) -> PprPrec -> IfaceTyCon -> [(a, ArgFlag)] -> SDoc ppr_iface_tc_app pp _ tc [ty] | tc `ifaceTyConHasKey` listTyConKey = pprPromotionQuote tc <> brackets (pp topPrec ty) ppr_iface_tc_app pp ctxt_prec tc tys | tc `ifaceTyConHasKey` liftedTypeKindTyConKey = kindType | not (isSymOcc (nameOccName (ifaceTyConName tc))) = pprIfacePrefixApp ctxt_prec (ppr tc) (map (pp appPrec) tys) | [ ty1@(_, Required) , ty2@(_, Required) ] <- tys -- Infix, two visible arguments (we know nothing of precedence though). -- Don't apply this special case if one of the arguments is invisible, -- lest we print something like (@LiftedRep -> @LiftedRep) (#15941). = pprIfaceInfixApp ctxt_prec (ppr tc) (pp opPrec ty1) (pp opPrec ty2) | otherwise = pprIfacePrefixApp ctxt_prec (parens (ppr tc)) (map (pp appPrec) tys) pprSum :: Arity -> PromotionFlag -> IfaceAppArgs -> SDoc pprSum _arity is_promoted args = -- drop the RuntimeRep vars. -- See Note [Unboxed tuple RuntimeRep vars] in TyCon let tys = appArgsIfaceTypes args args' = drop (length tys `div` 2) tys in pprPromotionQuoteI is_promoted <> sumParens (pprWithBars (ppr_ty topPrec) args') pprTuple :: PprPrec -> TupleSort -> PromotionFlag -> IfaceAppArgs -> SDoc pprTuple ctxt_prec ConstraintTuple NotPromoted IA_Nil = maybeParen ctxt_prec appPrec $ text "() :: Constraint" -- All promoted constructors have kind arguments pprTuple _ sort IsPromoted args = let tys = appArgsIfaceTypes args args' = drop (length tys `div` 2) tys spaceIfPromoted = case args' of arg0:_ -> pprSpaceIfPromotedTyCon arg0 _ -> id in pprPromotionQuoteI IsPromoted <> tupleParens sort (spaceIfPromoted (pprWithCommas pprIfaceType args')) pprTuple _ sort promoted args = -- drop the RuntimeRep vars. -- See Note [Unboxed tuple RuntimeRep vars] in TyCon let tys = appArgsIfaceTypes args args' = case sort of UnboxedTuple -> drop (length tys `div` 2) tys _ -> tys in pprPromotionQuoteI promoted <> tupleParens sort (pprWithCommas pprIfaceType args') pprIfaceTyLit :: IfaceTyLit -> SDoc pprIfaceTyLit (IfaceNumTyLit n) = integer n pprIfaceTyLit (IfaceStrTyLit n) = text (show n) pprIfaceCoercion, pprParendIfaceCoercion :: IfaceCoercion -> SDoc pprIfaceCoercion = ppr_co topPrec pprParendIfaceCoercion = ppr_co appPrec ppr_co :: PprPrec -> IfaceCoercion -> SDoc ppr_co _ (IfaceReflCo ty) = angleBrackets (ppr ty) <> ppr_role Nominal ppr_co _ (IfaceGReflCo r ty IfaceMRefl) = angleBrackets (ppr ty) <> ppr_role r ppr_co ctxt_prec (IfaceGReflCo r ty (IfaceMCo co)) = ppr_special_co ctxt_prec (text "GRefl" <+> ppr r <+> pprParendIfaceType ty) [co] ppr_co ctxt_prec (IfaceFunCo r co1 co2) = maybeParen ctxt_prec funPrec $ sep (ppr_co funPrec co1 : ppr_fun_tail co2) where ppr_fun_tail (IfaceFunCo r co1 co2) = (arrow <> ppr_role r <+> ppr_co funPrec co1) : ppr_fun_tail co2 ppr_fun_tail other_co = [arrow <> ppr_role r <+> pprIfaceCoercion other_co] ppr_co _ (IfaceTyConAppCo r tc cos) = parens (pprIfaceCoTcApp topPrec tc cos) <> ppr_role r ppr_co ctxt_prec (IfaceAppCo co1 co2) = maybeParen ctxt_prec appPrec $ ppr_co funPrec co1 <+> pprParendIfaceCoercion co2 ppr_co ctxt_prec co@(IfaceForAllCo {}) = maybeParen ctxt_prec funPrec $ pprIfaceForAllCoPart tvs (pprIfaceCoercion inner_co) where (tvs, inner_co) = split_co co split_co (IfaceForAllCo (IfaceTvBndr (name, _)) kind_co co') = let (tvs, co'') = split_co co' in ((name,kind_co):tvs,co'') split_co (IfaceForAllCo (IfaceIdBndr (name, _)) kind_co co') = let (tvs, co'') = split_co co' in ((name,kind_co):tvs,co'') split_co co' = ([], co') -- Why these three? See Note [TcTyVars in IfaceType] ppr_co _ (IfaceFreeCoVar covar) = ppr covar ppr_co _ (IfaceCoVarCo covar) = ppr covar ppr_co _ (IfaceHoleCo covar) = braces (ppr covar) ppr_co ctxt_prec (IfaceUnivCo IfaceUnsafeCoerceProv r ty1 ty2) = maybeParen ctxt_prec appPrec $ text "UnsafeCo" <+> ppr r <+> pprParendIfaceType ty1 <+> pprParendIfaceType ty2 ppr_co _ (IfaceUnivCo prov role ty1 ty2) = text "Univ" <> (parens $ sep [ ppr role <+> pprIfaceUnivCoProv prov , dcolon <+> ppr ty1 <> comma <+> ppr ty2 ]) ppr_co ctxt_prec (IfaceInstCo co ty) = maybeParen ctxt_prec appPrec $ text "Inst" <+> pprParendIfaceCoercion co <+> pprParendIfaceCoercion ty ppr_co ctxt_prec (IfaceAxiomRuleCo tc cos) = maybeParen ctxt_prec appPrec $ ppr tc <+> parens (interpp'SP cos) ppr_co ctxt_prec (IfaceAxiomInstCo n i cos) = ppr_special_co ctxt_prec (ppr n <> brackets (ppr i)) cos ppr_co ctxt_prec (IfaceSymCo co) = ppr_special_co ctxt_prec (text "Sym") [co] ppr_co ctxt_prec (IfaceTransCo co1 co2) = maybeParen ctxt_prec opPrec $ ppr_co opPrec co1 <+> semi <+> ppr_co opPrec co2 ppr_co ctxt_prec (IfaceNthCo d co) = ppr_special_co ctxt_prec (text "Nth:" <> int d) [co] ppr_co ctxt_prec (IfaceLRCo lr co) = ppr_special_co ctxt_prec (ppr lr) [co] ppr_co ctxt_prec (IfaceSubCo co) = ppr_special_co ctxt_prec (text "Sub") [co] ppr_co ctxt_prec (IfaceKindCo co) = ppr_special_co ctxt_prec (text "Kind") [co] ppr_special_co :: PprPrec -> SDoc -> [IfaceCoercion] -> SDoc ppr_special_co ctxt_prec doc cos = maybeParen ctxt_prec appPrec (sep [doc, nest 4 (sep (map pprParendIfaceCoercion cos))]) ppr_role :: Role -> SDoc ppr_role r = underscore <> pp_role where pp_role = case r of Nominal -> char 'N' Representational -> char 'R' Phantom -> char 'P' ------------------ pprIfaceUnivCoProv :: IfaceUnivCoProv -> SDoc pprIfaceUnivCoProv IfaceUnsafeCoerceProv = text "unsafe" pprIfaceUnivCoProv (IfacePhantomProv co) = text "phantom" <+> pprParendIfaceCoercion co pprIfaceUnivCoProv (IfaceProofIrrelProv co) = text "irrel" <+> pprParendIfaceCoercion co pprIfaceUnivCoProv (IfacePluginProv s) = text "plugin" <+> doubleQuotes (text s) ------------------- instance Outputable IfaceTyCon where ppr tc = pprPromotionQuote tc <> ppr (ifaceTyConName tc) pprPromotionQuote :: IfaceTyCon -> SDoc pprPromotionQuote tc = pprPromotionQuoteI $ ifaceTyConIsPromoted $ ifaceTyConInfo tc pprPromotionQuoteI :: PromotionFlag -> SDoc pprPromotionQuoteI NotPromoted = empty pprPromotionQuoteI IsPromoted = char '\'' instance Outputable IfaceCoercion where ppr = pprIfaceCoercion instance Binary IfaceTyCon where put_ bh (IfaceTyCon n i) = put_ bh n >> put_ bh i get bh = do n <- get bh i <- get bh return (IfaceTyCon n i) instance Binary IfaceTyConSort where put_ bh IfaceNormalTyCon = putByte bh 0 put_ bh (IfaceTupleTyCon arity sort) = putByte bh 1 >> put_ bh arity >> put_ bh sort put_ bh (IfaceSumTyCon arity) = putByte bh 2 >> put_ bh arity put_ bh IfaceEqualityTyCon = putByte bh 3 get bh = do n <- getByte bh case n of 0 -> return IfaceNormalTyCon 1 -> IfaceTupleTyCon <$> get bh <*> get bh 2 -> IfaceSumTyCon <$> get bh _ -> return IfaceEqualityTyCon instance Binary IfaceTyConInfo where put_ bh (IfaceTyConInfo i s) = put_ bh i >> put_ bh s get bh = IfaceTyConInfo <$> get bh <*> get bh instance Outputable IfaceTyLit where ppr = pprIfaceTyLit instance Binary IfaceTyLit where put_ bh (IfaceNumTyLit n) = putByte bh 1 >> put_ bh n put_ bh (IfaceStrTyLit n) = putByte bh 2 >> put_ bh n get bh = do tag <- getByte bh case tag of 1 -> do { n <- get bh ; return (IfaceNumTyLit n) } 2 -> do { n <- get bh ; return (IfaceStrTyLit n) } _ -> panic ("get IfaceTyLit " ++ show tag) instance Binary IfaceAppArgs where put_ bh tk = case tk of IA_Arg t a ts -> putByte bh 0 >> put_ bh t >> put_ bh a >> put_ bh ts IA_Nil -> putByte bh 1 get bh = do c <- getByte bh case c of 0 -> do t <- get bh a <- get bh ts <- get bh return $! IA_Arg t a ts 1 -> return IA_Nil _ -> panic ("get IfaceAppArgs " ++ show c) ------------------- -- Some notes about printing contexts -- -- In the event that we are printing a singleton context (e.g. @Eq a@) we can -- omit parentheses. However, we must take care to set the precedence correctly -- to opPrec, since something like @a :~: b@ must be parenthesized (see -- #9658). -- -- When printing a larger context we use 'fsep' instead of 'sep' so that -- the context doesn't get displayed as a giant column. Rather than, -- instance (Eq a, -- Eq b, -- Eq c, -- Eq d, -- Eq e, -- Eq f, -- Eq g, -- Eq h, -- Eq i, -- Eq j, -- Eq k, -- Eq l) => -- Eq (a, b, c, d, e, f, g, h, i, j, k, l) -- -- we want -- -- instance (Eq a, Eq b, Eq c, Eq d, Eq e, Eq f, Eq g, Eq h, Eq i, -- Eq j, Eq k, Eq l) => -- Eq (a, b, c, d, e, f, g, h, i, j, k, l) -- | Prints "(C a, D b) =>", including the arrow. -- Used when we want to print a context in a type, so we -- use 'funPrec' to decide whether to parenthesise a singleton -- predicate; e.g. Num a => a -> a pprIfaceContextArr :: [IfacePredType] -> SDoc pprIfaceContextArr [] = empty pprIfaceContextArr [pred] = ppr_ty funPrec pred <+> darrow pprIfaceContextArr preds = ppr_parend_preds preds <+> darrow -- | Prints a context or @()@ if empty -- You give it the context precedence pprIfaceContext :: PprPrec -> [IfacePredType] -> SDoc pprIfaceContext _ [] = text "()" pprIfaceContext prec [pred] = ppr_ty prec pred pprIfaceContext _ preds = ppr_parend_preds preds ppr_parend_preds :: [IfacePredType] -> SDoc ppr_parend_preds preds = parens (fsep (punctuate comma (map ppr preds))) instance Binary IfaceType where put_ _ (IfaceFreeTyVar tv) = pprPanic "Can't serialise IfaceFreeTyVar" (ppr tv) put_ bh (IfaceForAllTy aa ab) = do putByte bh 0 put_ bh aa put_ bh ab put_ bh (IfaceTyVar ad) = do putByte bh 1 put_ bh ad put_ bh (IfaceAppTy ae af) = do putByte bh 2 put_ bh ae put_ bh af put_ bh (IfaceFunTy ag ah) = do putByte bh 3 put_ bh ag put_ bh ah put_ bh (IfaceDFunTy ag ah) = do putByte bh 4 put_ bh ag put_ bh ah put_ bh (IfaceTyConApp tc tys) = do { putByte bh 5; put_ bh tc; put_ bh tys } put_ bh (IfaceCastTy a b) = do { putByte bh 6; put_ bh a; put_ bh b } put_ bh (IfaceCoercionTy a) = do { putByte bh 7; put_ bh a } put_ bh (IfaceTupleTy s i tys) = do { putByte bh 8; put_ bh s; put_ bh i; put_ bh tys } put_ bh (IfaceLitTy n) = do { putByte bh 9; put_ bh n } get bh = do h <- getByte bh case h of 0 -> do aa <- get bh ab <- get bh return (IfaceForAllTy aa ab) 1 -> do ad <- get bh return (IfaceTyVar ad) 2 -> do ae <- get bh af <- get bh return (IfaceAppTy ae af) 3 -> do ag <- get bh ah <- get bh return (IfaceFunTy ag ah) 4 -> do ag <- get bh ah <- get bh return (IfaceDFunTy ag ah) 5 -> do { tc <- get bh; tys <- get bh ; return (IfaceTyConApp tc tys) } 6 -> do { a <- get bh; b <- get bh ; return (IfaceCastTy a b) } 7 -> do { a <- get bh ; return (IfaceCoercionTy a) } 8 -> do { s <- get bh; i <- get bh; tys <- get bh ; return (IfaceTupleTy s i tys) } _ -> do n <- get bh return (IfaceLitTy n) instance Binary IfaceMCoercion where put_ bh IfaceMRefl = do putByte bh 1 put_ bh (IfaceMCo co) = do putByte bh 2 put_ bh co get bh = do tag <- getByte bh case tag of 1 -> return IfaceMRefl 2 -> do a <- get bh return $ IfaceMCo a _ -> panic ("get IfaceMCoercion " ++ show tag) instance Binary IfaceCoercion where put_ bh (IfaceReflCo a) = do putByte bh 1 put_ bh a put_ bh (IfaceGReflCo a b c) = do putByte bh 2 put_ bh a put_ bh b put_ bh c put_ bh (IfaceFunCo a b c) = do putByte bh 3 put_ bh a put_ bh b put_ bh c put_ bh (IfaceTyConAppCo a b c) = do putByte bh 4 put_ bh a put_ bh b put_ bh c put_ bh (IfaceAppCo a b) = do putByte bh 5 put_ bh a put_ bh b put_ bh (IfaceForAllCo a b c) = do putByte bh 6 put_ bh a put_ bh b put_ bh c put_ bh (IfaceCoVarCo a) = do putByte bh 7 put_ bh a put_ bh (IfaceAxiomInstCo a b c) = do putByte bh 8 put_ bh a put_ bh b put_ bh c put_ bh (IfaceUnivCo a b c d) = do putByte bh 9 put_ bh a put_ bh b put_ bh c put_ bh d put_ bh (IfaceSymCo a) = do putByte bh 10 put_ bh a put_ bh (IfaceTransCo a b) = do putByte bh 11 put_ bh a put_ bh b put_ bh (IfaceNthCo a b) = do putByte bh 12 put_ bh a put_ bh b put_ bh (IfaceLRCo a b) = do putByte bh 13 put_ bh a put_ bh b put_ bh (IfaceInstCo a b) = do putByte bh 14 put_ bh a put_ bh b put_ bh (IfaceKindCo a) = do putByte bh 15 put_ bh a put_ bh (IfaceSubCo a) = do putByte bh 16 put_ bh a put_ bh (IfaceAxiomRuleCo a b) = do putByte bh 17 put_ bh a put_ bh b put_ _ (IfaceFreeCoVar cv) = pprPanic "Can't serialise IfaceFreeCoVar" (ppr cv) put_ _ (IfaceHoleCo cv) = pprPanic "Can't serialise IfaceHoleCo" (ppr cv) -- See Note [Holes in IfaceCoercion] get bh = do tag <- getByte bh case tag of 1 -> do a <- get bh return $ IfaceReflCo a 2 -> do a <- get bh b <- get bh c <- get bh return $ IfaceGReflCo a b c 3 -> do a <- get bh b <- get bh c <- get bh return $ IfaceFunCo a b c 4 -> do a <- get bh b <- get bh c <- get bh return $ IfaceTyConAppCo a b c 5 -> do a <- get bh b <- get bh return $ IfaceAppCo a b 6 -> do a <- get bh b <- get bh c <- get bh return $ IfaceForAllCo a b c 7 -> do a <- get bh return $ IfaceCoVarCo a 8 -> do a <- get bh b <- get bh c <- get bh return $ IfaceAxiomInstCo a b c 9 -> do a <- get bh b <- get bh c <- get bh d <- get bh return $ IfaceUnivCo a b c d 10-> do a <- get bh return $ IfaceSymCo a 11-> do a <- get bh b <- get bh return $ IfaceTransCo a b 12-> do a <- get bh b <- get bh return $ IfaceNthCo a b 13-> do a <- get bh b <- get bh return $ IfaceLRCo a b 14-> do a <- get bh b <- get bh return $ IfaceInstCo a b 15-> do a <- get bh return $ IfaceKindCo a 16-> do a <- get bh return $ IfaceSubCo a 17-> do a <- get bh b <- get bh return $ IfaceAxiomRuleCo a b _ -> panic ("get IfaceCoercion " ++ show tag) instance Binary IfaceUnivCoProv where put_ bh IfaceUnsafeCoerceProv = putByte bh 1 put_ bh (IfacePhantomProv a) = do putByte bh 2 put_ bh a put_ bh (IfaceProofIrrelProv a) = do putByte bh 3 put_ bh a put_ bh (IfacePluginProv a) = do putByte bh 4 put_ bh a get bh = do tag <- getByte bh case tag of 1 -> return $ IfaceUnsafeCoerceProv 2 -> do a <- get bh return $ IfacePhantomProv a 3 -> do a <- get bh return $ IfaceProofIrrelProv a 4 -> do a <- get bh return $ IfacePluginProv a _ -> panic ("get IfaceUnivCoProv " ++ show tag) instance Binary (DefMethSpec IfaceType) where put_ bh VanillaDM = putByte bh 0 put_ bh (GenericDM t) = putByte bh 1 >> put_ bh t get bh = do h <- getByte bh case h of 0 -> return VanillaDM _ -> do { t <- get bh; return (GenericDM t) }