[Git][ghc/ghc][wip/marge_bot_batch_merge_job] 4 commits: Fix rtsopts documentation
Marge Bot
gitlab at gitlab.haskell.org
Tue Sep 15 06:38:44 UTC 2020
Marge Bot pushed to branch wip/marge_bot_batch_merge_job at Glasgow Haskell Compiler / GHC
Commits:
5ed31f64 by DenisFrezzato at 2020-09-15T02:38:29-04:00
Fix rtsopts documentation
- - - - -
dbb4f9d6 by Simon Peyton Jones at 2020-09-15T02:38:30-04:00
Care with implicit-parameter superclasses
Two bugs, #18627 and #18649, had the same cause: we were not
account for the fact that a constaint tuple might hide an implicit
parameter.
The solution is not hard: look for implicit parameters in
superclasses. See Note [Local implicit parameters] in
GHC.Core.Predicate.
Then we use this new function in two places
* The "short-cut solver" in GHC.Tc.Solver.Interact.shortCutSolver
which simply didn't handle implicit parameters properly at all.
This fixes #18627
* The specialiser, which should not specialise on implicit parameters
This fixes #18649
There are some lingering worries (see Note [Local implicit
parameters]) but things are much better.
- - - - -
e3350f96 by Zubin Duggal at 2020-09-15T02:38:32-04:00
Export enrichHie from GHC.Iface.Ext.Ast
This is useful for `ghcide`
- - - - -
15748dcb by Ryan Scott at 2020-09-15T02:38:32-04:00
Introduce and use DerivClauseTys (#18662)
This switches `deriv_clause_tys` so that instead of using a list of
`LHsSigType`s to represent the types in a `deriving` clause, it now
uses a sum type. `DctSingle` represents a `deriving` clause with no
enclosing parentheses, while `DctMulti` represents a clause with
enclosing parentheses. This makes pretty-printing easier and avoids
confusion between `HsParTy` and the enclosing parentheses in
`deriving` clauses, which are different semantically.
Fixes #18662.
- - - - -
28 changed files:
- compiler/GHC/Core/Opt/Specialise.hs
- compiler/GHC/Core/Predicate.hs
- compiler/GHC/Hs/Decls.hs
- compiler/GHC/Hs/Extension.hs
- compiler/GHC/Hs/Instances.hs
- compiler/GHC/HsToCore/Docs.hs
- compiler/GHC/HsToCore/Quote.hs
- compiler/GHC/Iface/Ext/Ast.hs
- compiler/GHC/Parser.y
- compiler/GHC/Parser/PostProcess/Haddock.hs
- compiler/GHC/Rename/Module.hs
- compiler/GHC/Tc/Deriv.hs
- compiler/GHC/Tc/Instance/Class.hs
- compiler/GHC/Tc/Module.hs
- compiler/GHC/Tc/Solver.hs
- compiler/GHC/Tc/Solver/Canonical.hs
- compiler/GHC/Tc/Solver/Interact.hs
- compiler/GHC/Tc/Solver/Monad.hs
- compiler/GHC/Tc/TyCl/Instance.hs
- compiler/GHC/Tc/Utils/TcType.hs
- compiler/GHC/ThToHs.hs
- docs/users_guide/phases.rst
- + testsuite/tests/simplCore/should_compile/T18649.hs
- + testsuite/tests/simplCore/should_compile/T18649.stderr
- testsuite/tests/simplCore/should_compile/all.T
- + testsuite/tests/typecheck/should_run/T18627.hs
- + testsuite/tests/typecheck/should_run/T18627.stdout
- testsuite/tests/typecheck/should_run/all.T
Changes:
=====================================
compiler/GHC/Core/Opt/Specialise.hs
=====================================
@@ -2514,9 +2514,12 @@ mkCallUDs' env f args
-- we decide on a case by case basis if we want to specialise
-- on this argument; if so, SpecDict, if not UnspecArg
mk_spec_arg arg (Anon InvisArg pred)
- | type_determines_value (scaledThing pred)
- , interestingDict env arg -- Note [Interesting dictionary arguments]
+ | not (isIPLikePred (scaledThing pred))
+ -- See Note [Type determines value]
+ , interestingDict env arg
+ -- See Note [Interesting dictionary arguments]
= SpecDict arg
+
| otherwise = UnspecArg
mk_spec_arg _ (Anon VisArg _)
@@ -2529,41 +2532,18 @@ mkCallUDs' env f args
-- in specImports
-- Use 'realIdUnfolding' to ignore the loop-breaker flag!
- type_determines_value pred -- See Note [Type determines value]
- = case classifyPredType pred of
- ClassPred cls _ -> not (isIPClass cls) -- Superclasses can't be IPs
- EqPred {} -> True
- IrredPred {} -> True -- Things like (D []) where D is a
- -- Constraint-ranged family; #7785
- ForAllPred {} -> True
-
-{-
-Note [Type determines value]
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-Only specialise on non-IP *class* params, because these are the ones
-whose *type* determines their *value*. In particular, with implicit
-params, the type args *don't* say what the value of the implicit param
-is! See #7101.
+{- Note [Type determines value]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Only specialise on non-impicit-parameter predicates, because these
+are the ones whose *type* determines their *value*. In particular,
+with implicit params, the type args *don't* say what the value of the
+implicit param is! See #7101.
So we treat implicit params just like ordinary arguments for the
purposes of specialisation. Note that we still want to specialise
functions with implicit params if they have *other* dicts which are
class params; see #17930.
-One apparent additional complexity involves type families. For
-example, consider
- type family D (v::*->*) :: Constraint
- type instance D [] = ()
- f :: D v => v Char -> Int
-If we see a call (f "foo"), we'll pass a "dictionary"
- () |> (g :: () ~ D [])
-and it's good to specialise f at this dictionary.
-
-So the question is: can an implicit parameter "hide inside" a
-type-family constraint like (D a). Well, no. We don't allow
- type instance D Maybe = ?x:Int
-Hence the IrredPred case in type_determines_value. See #7785.
-
Note [Interesting dictionary arguments]
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Consider this
=====================================
compiler/GHC/Core/Predicate.hs
=====================================
@@ -20,9 +20,10 @@ module GHC.Core.Predicate (
mkClassPred, isDictTy,
isClassPred, isEqPredClass, isCTupleClass,
getClassPredTys, getClassPredTys_maybe,
+ classMethodTy, classMethodInstTy,
-- Implicit parameters
- isIPPred, isIPPred_maybe, isIPTyCon, isIPClass, hasIPPred,
+ isIPLikePred, hasIPSuperClasses, isIPTyCon, isIPClass,
-- Evidence variables
DictId, isEvVar, isDictId
@@ -39,12 +40,10 @@ import GHC.Core.Multiplicity ( scaledThing )
import GHC.Builtin.Names
-import GHC.Data.FastString
import GHC.Utils.Outputable
import GHC.Utils.Misc
import GHC.Utils.Panic
-import Control.Monad ( guard )
-- | A predicate in the solver. The solver tries to prove Wanted predicates
-- from Given ones.
@@ -95,6 +94,26 @@ getClassPredTys_maybe ty = case splitTyConApp_maybe ty of
Just (tc, tys) | Just clas <- tyConClass_maybe tc -> Just (clas, tys)
_ -> Nothing
+classMethodTy :: Id -> Type
+-- Takes a class selector op :: forall a. C a => meth_ty
+-- and returns the type of its method, meth_ty
+-- The selector can be a superclass selector, in which case
+-- you get back a superclass
+classMethodTy sel_id
+ = funResultTy $ -- meth_ty
+ dropForAlls $ -- C a => meth_ty
+ varType sel_id -- forall a. C n => meth_ty
+
+classMethodInstTy :: Id -> [Type] -> Type
+-- Takes a class selector op :: forall a b. C a b => meth_ty
+-- and the types [ty1, ty2] at which it is instantiated,
+-- returns the instantiated type of its method, meth_ty[t1/a,t2/b]
+-- The selector can be a superclass selector, in which case
+-- you get back a superclass
+classMethodInstTy sel_id arg_tys
+ = funResultTy $
+ piResultTys (varType sel_id) arg_tys
+
-- --------------------- Equality predicates ---------------------------------
-- | A choice of equality relation. This is separate from the type 'Role'
@@ -170,7 +189,7 @@ isEqPredClass :: Class -> Bool
isEqPredClass cls = cls `hasKey` eqTyConKey
|| cls `hasKey` heqTyConKey
-isClassPred, isEqPred, isEqPrimPred, isIPPred :: PredType -> Bool
+isClassPred, isEqPred, isEqPrimPred :: PredType -> Bool
isClassPred ty = case tyConAppTyCon_maybe ty of
Just tyCon | isClassTyCon tyCon -> True
_ -> False
@@ -186,9 +205,15 @@ isEqPred ty -- True of (a ~ b) and (a ~~ b)
isEqPrimPred ty = isCoVarType ty
-- True of (a ~# b) (a ~R# b)
-isIPPred ty = case tyConAppTyCon_maybe ty of
- Just tc -> isIPTyCon tc
- _ -> False
+isCTupleClass :: Class -> Bool
+isCTupleClass cls = isTupleTyCon (classTyCon cls)
+
+
+{- *********************************************************************
+* *
+ Implicit parameters
+* *
+********************************************************************* -}
isIPTyCon :: TyCon -> Bool
isIPTyCon tc = tc `hasKey` ipClassKey
@@ -197,31 +222,103 @@ isIPTyCon tc = tc `hasKey` ipClassKey
isIPClass :: Class -> Bool
isIPClass cls = cls `hasKey` ipClassKey
-isCTupleClass :: Class -> Bool
-isCTupleClass cls = isTupleTyCon (classTyCon cls)
+isIPLikePred :: Type -> Bool
+-- See Note [Local implicit parameters]
+isIPLikePred = is_ip_like_pred initIPRecTc
-isIPPred_maybe :: Type -> Maybe (FastString, Type)
-isIPPred_maybe ty =
- do (tc,[t1,t2]) <- splitTyConApp_maybe ty
- guard (isIPTyCon tc)
- x <- isStrLitTy t1
- return (x,t2)
-
-hasIPPred :: PredType -> Bool
-hasIPPred pred
- = case classifyPredType pred of
- ClassPred cls tys
- | isIPClass cls -> True
- | isCTupleClass cls -> any hasIPPred tys
- _other -> False
-{-
-************************************************************************
+is_ip_like_pred :: RecTcChecker -> Type -> Bool
+is_ip_like_pred rec_clss ty
+ | Just (tc, tys) <- splitTyConApp_maybe ty
+ , Just rec_clss' <- if isTupleTyCon tc -- Tuples never cause recursion
+ then Just rec_clss
+ else checkRecTc rec_clss tc
+ , Just cls <- tyConClass_maybe tc
+ = isIPClass cls || has_ip_super_classes rec_clss' cls tys
+
+ | otherwise
+ = False -- Includes things like (D []) where D is
+ -- a Constraint-ranged family; #7785
+
+hasIPSuperClasses :: Class -> [Type] -> Bool
+-- See Note [Local implicit parameters]
+hasIPSuperClasses = has_ip_super_classes initIPRecTc
+
+has_ip_super_classes :: RecTcChecker -> Class -> [Type] -> Bool
+has_ip_super_classes rec_clss cls tys
+ = any ip_ish (classSCSelIds cls)
+ where
+ -- Check that the type of a superclass determines its value
+ -- sc_sel_id :: forall a b. C a b -> <superclass type>
+ ip_ish sc_sel_id = is_ip_like_pred rec_clss $
+ classMethodInstTy sc_sel_id tys
+
+initIPRecTc :: RecTcChecker
+initIPRecTc = setRecTcMaxBound 1 initRecTc
+
+{- Note [Local implicit parameters]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+The function isIPLikePred tells if this predicate, or any of its
+superclasses, is an implicit parameter.
+
+Why are implicit parameters special? Unlike normal classes, we can
+have local instances for implicit parameters, in the form of
+ let ?x = True in ...
+So in various places we must be careful not to assume that any value
+of the right type will do; we must carefully look for the innermost binding.
+So isIPLikePred checks whether this is an implicit parameter, or has
+a superclass that is an implicit parameter.
+
+Several wrinkles
+
+* We must be careful with superclasses, as #18649 showed. Haskell
+ doesn't allow an implicit parameter as a superclass
+ class (?x::a) => C a where ...
+ but with a constraint tuple we might have
+ (% Eq a, ?x::Int %)
+ and /its/ superclasses, namely (Eq a) and (?x::Int), /do/ include an
+ implicit parameter.
+
+ With ConstraintKinds this can apply to /any/ class, e.g.
+ class sc => C sc where ...
+ Then (C (?x::Int)) has (?x::Int) as a superclass. So we must
+ instantiate and check each superclass, one by one, in
+ hasIPSuperClasses.
+
+* With -XRecursiveSuperClasses, the superclass hunt can go on forever,
+ so we need a RecTcChecker to cut it off.
+
+* Another apparent additional complexity involves type families. For
+ example, consider
+ type family D (v::*->*) :: Constraint
+ type instance D [] = ()
+ f :: D v => v Char -> Int
+ If we see a call (f "foo"), we'll pass a "dictionary"
+ () |> (g :: () ~ D [])
+ and it's good to specialise f at this dictionary.
+
+So the question is: can an implicit parameter "hide inside" a
+type-family constraint like (D a). Well, no. We don't allow
+ type instance D Maybe = ?x:Int
+Hence the umbrella 'otherwise' case in is_ip_like_pred. See #7785.
+
+Small worries (Sept 20):
+* I don't see what stops us having that 'type instance'. Indeed I
+ think nothing does.
+* I'm a little concerned about type variables; such a variable might
+ be instantiated to an implicit parameter. I don't think this
+ matters in the cases for which isIPLikePred is used, and it's pretty
+ obscure anyway.
+* The superclass hunt stops when it encounters the same class again,
+ but in principle we could have the same class, differently instantiated,
+ and the second time it could have an implicit parameter
+I'm going to treat these as problems for another day. They are all exotic. -}
+
+{- *********************************************************************
* *
Evidence variables
* *
-************************************************************************
--}
+********************************************************************* -}
isEvVar :: Var -> Bool
isEvVar var = isEvVarType (varType var)
=====================================
compiler/GHC/Hs/Decls.hs
=====================================
@@ -25,7 +25,8 @@
module GHC.Hs.Decls (
-- * Toplevel declarations
HsDecl(..), LHsDecl, HsDataDefn(..), HsDeriving, LHsFunDep,
- HsDerivingClause(..), LHsDerivingClause, NewOrData(..), newOrDataToFlavour,
+ HsDerivingClause(..), LHsDerivingClause, DerivClauseTys(..), LDerivClauseTys,
+ NewOrData(..), newOrDataToFlavour,
StandaloneKindSig(..), LStandaloneKindSig, standaloneKindSigName,
-- ** Class or type declarations
@@ -1321,15 +1322,8 @@ data HsDerivingClause pass
, deriv_clause_strategy :: Maybe (LDerivStrategy pass)
-- ^ The user-specified strategy (if any) to use when deriving
-- 'deriv_clause_tys'.
- , deriv_clause_tys :: XRec pass [LHsSigType pass]
+ , deriv_clause_tys :: LDerivClauseTys pass
-- ^ The types to derive.
- --
- -- It uses 'LHsSigType's because, with @-XGeneralizedNewtypeDeriving@,
- -- we can mention type variables that aren't bound by the datatype, e.g.
- --
- -- > data T b = ... deriving (C [a])
- --
- -- should produce a derived instance for @C [a] (T b)@.
}
| XHsDerivingClause !(XXHsDerivingClause pass)
@@ -1342,16 +1336,9 @@ instance OutputableBndrId p
, deriv_clause_tys = L _ dct })
= hsep [ text "deriving"
, pp_strat_before
- , pp_dct dct
+ , ppr dct
, pp_strat_after ]
where
- -- This complexity is to distinguish between
- -- deriving Show
- -- deriving (Show)
- pp_dct [HsIB { hsib_body = ty }]
- = ppr (parenthesizeHsType appPrec ty)
- pp_dct _ = parens (interpp'SP dct)
-
-- @via@ is unique in that in comes /after/ the class being derived,
-- so we must special-case it.
(pp_strat_before, pp_strat_after) =
@@ -1359,6 +1346,43 @@ instance OutputableBndrId p
Just (L _ via at ViaStrategy{}) -> (empty, ppr via)
_ -> (ppDerivStrategy dcs, empty)
+type LDerivClauseTys pass = XRec pass (DerivClauseTys pass)
+
+-- | The types mentioned in a single @deriving@ clause. This can come in two
+-- forms, 'DctSingle' or 'DctMulti', depending on whether the types are
+-- surrounded by enclosing parentheses or not. These parentheses are
+-- semantically differnt than 'HsParTy'. For example, @deriving ()@ means
+-- \"derive zero classes\" rather than \"derive an instance of the 0-tuple\".
+--
+-- 'DerivClauseTys' use 'LHsSigType' because @deriving@ clauses can mention
+-- type variables that aren't bound by the datatype, e.g.
+--
+-- > data T b = ... deriving (C [a])
+--
+-- should produce a derived instance for @C [a] (T b)@.
+data DerivClauseTys pass
+ = -- | A @deriving@ clause with a single type. Moreover, that type can only
+ -- be a type constructor without any arguments.
+ --
+ -- Example: @deriving Eq@
+ DctSingle (XDctSingle pass) (LHsSigType pass)
+
+ -- | A @deriving@ clause with a comma-separated list of types, surrounded
+ -- by enclosing parentheses.
+ --
+ -- Example: @deriving (Eq, C a)@
+ | DctMulti (XDctMulti pass) [LHsSigType pass]
+
+ | XDerivClauseTys !(XXDerivClauseTys pass)
+
+type instance XDctSingle (GhcPass _) = NoExtField
+type instance XDctMulti (GhcPass _) = NoExtField
+type instance XXDerivClauseTys (GhcPass _) = NoExtCon
+
+instance OutputableBndrId p => Outputable (DerivClauseTys (GhcPass p)) where
+ ppr (DctSingle _ ty) = ppr ty
+ ppr (DctMulti _ tys) = parens (interpp'SP tys)
+
-- | Located Standalone Kind Signature
type LStandaloneKindSig pass = XRec pass (StandaloneKindSig pass)
=====================================
compiler/GHC/Hs/Extension.hs
=====================================
@@ -446,6 +446,12 @@ type family XXHsDataDefn x
type family XCHsDerivingClause x
type family XXHsDerivingClause x
+-- -------------------------------------
+-- DerivClauseTys type families
+type family XDctSingle x
+type family XDctMulti x
+type family XXDerivClauseTys x
+
-- -------------------------------------
-- ConDecl type families
type family XConDeclGADT x
=====================================
compiler/GHC/Hs/Instances.hs
=====================================
@@ -163,6 +163,11 @@ deriving instance Data (HsDerivingClause GhcPs)
deriving instance Data (HsDerivingClause GhcRn)
deriving instance Data (HsDerivingClause GhcTc)
+-- deriving instance DataIdLR p p => Data (DerivClauseTys p)
+deriving instance Data (DerivClauseTys GhcPs)
+deriving instance Data (DerivClauseTys GhcRn)
+deriving instance Data (DerivClauseTys GhcTc)
+
-- deriving instance (DataIdLR p p) => Data (ConDecl p)
deriving instance Data (ConDecl GhcPs)
deriving instance Data (ConDecl GhcRn)
=====================================
compiler/GHC/HsToCore/Docs.hs
=====================================
@@ -193,13 +193,19 @@ subordinates instMap decl = case decl of
, (L _ (ConDeclField _ ns _ doc)) <- (unLoc flds)
, (L _ n) <- ns ]
derivs = [ (instName, [unLoc doc], M.empty)
- | (l, doc) <- mapMaybe (extract_deriv_ty . hsib_body) $
- concatMap (unLoc . deriv_clause_tys . unLoc) $
+ | (l, doc) <- concatMap (extract_deriv_clause_tys .
+ deriv_clause_tys . unLoc) $
unLoc $ dd_derivs dd
, Just instName <- [lookupSrcSpan l instMap] ]
- extract_deriv_ty :: LHsType GhcRn -> Maybe (SrcSpan, LHsDocString)
- extract_deriv_ty (L l ty) =
+ extract_deriv_clause_tys :: LDerivClauseTys GhcRn -> [(SrcSpan, LHsDocString)]
+ extract_deriv_clause_tys (L _ dct) =
+ case dct of
+ DctSingle _ ty -> maybeToList $ extract_deriv_ty ty
+ DctMulti _ tys -> mapMaybe extract_deriv_ty tys
+
+ extract_deriv_ty :: LHsSigType GhcRn -> Maybe (SrcSpan, LHsDocString)
+ extract_deriv_ty (HsIB{hsib_body = L l ty}) =
case ty of
-- deriving (forall a. C a {- ^ Doc comment -})
HsForAllTy{ hst_tele = HsForAllInvis{}
=====================================
compiler/GHC/HsToCore/Quote.hs
=====================================
@@ -945,13 +945,18 @@ repDerivClause :: LHsDerivingClause GhcRn
-> MetaM (Core (M TH.DerivClause))
repDerivClause (L _ (HsDerivingClause
{ deriv_clause_strategy = dcs
- , deriv_clause_tys = L _ dct }))
+ , deriv_clause_tys = dct }))
= repDerivStrategy dcs $ \(MkC dcs') ->
- do MkC dct' <- repListM typeTyConName (rep_deriv_ty . hsSigType) dct
+ do MkC dct' <- rep_deriv_clause_tys dct
rep2 derivClauseName [dcs',dct']
where
- rep_deriv_ty :: LHsType GhcRn -> MetaM (Core (M TH.Type))
- rep_deriv_ty ty = repLTy ty
+ rep_deriv_clause_tys :: LDerivClauseTys GhcRn -> MetaM (Core [M TH.Type])
+ rep_deriv_clause_tys (L _ dct) = case dct of
+ DctSingle _ ty -> rep_deriv_tys [ty]
+ DctMulti _ tys -> rep_deriv_tys tys
+
+ rep_deriv_tys :: [LHsSigType GhcRn] -> MetaM (Core [M TH.Type])
+ rep_deriv_tys = repListM typeTyConName (repLTy . hsSigType)
rep_meth_sigs_binds :: [LSig GhcRn] -> LHsBinds GhcRn
-> MetaM ([GenSymBind], [Core (M TH.Dec)])
=====================================
compiler/GHC/Iface/Ext/Ast.hs
=====================================
@@ -19,7 +19,7 @@ Main functions for .hie file generation
{-# LANGUAGE TupleSections #-}
{-# OPTIONS_GHC -Wno-incomplete-uni-patterns #-}
-module GHC.Iface.Ext.Ast ( mkHieFile, mkHieFileWithSource, getCompressedAsts) where
+module GHC.Iface.Ext.Ast ( mkHieFile, mkHieFileWithSource, getCompressedAsts, enrichHie) where
import GHC.Utils.Outputable(ppr)
@@ -1507,12 +1507,16 @@ instance ToHie (Located [Located (HsDerivingClause GhcRn)]) where
instance ToHie (Located (HsDerivingClause GhcRn)) where
toHie (L span cl) = concatM $ makeNode cl span : case cl of
- HsDerivingClause _ strat (L ispan tys) ->
+ HsDerivingClause _ strat dct ->
[ toHie strat
- , locOnly ispan
- , toHie $ map (TS (ResolvedScopes [])) tys
+ , toHie dct
]
+instance ToHie (Located (DerivClauseTys GhcRn)) where
+ toHie (L span dct) = concatM $ makeNode dct span : case dct of
+ DctSingle _ ty -> [ toHie $ TS (ResolvedScopes[]) ty ]
+ DctMulti _ tys -> [ toHie $ map (TS (ResolvedScopes [])) tys ]
+
instance ToHie (Located (DerivStrategy GhcRn)) where
toHie (L span strat) = concatM $ makeNode strat span : case strat of
StockStrategy -> []
=====================================
compiler/GHC/Parser.y
=====================================
@@ -2276,15 +2276,13 @@ deriving :: { LHsDerivingClause GhcPs }
in ams (L full_loc $ HsDerivingClause noExtField (Just $3) $2)
[mj AnnDeriving $1] }
-deriv_clause_types :: { Located [LHsSigType GhcPs] }
+deriv_clause_types :: { LDerivClauseTys GhcPs }
: qtycon { let { tc = sL1 $1 (HsTyVar noExtField NotPromoted $1) } in
- sL1 $1 [mkLHsSigType tc] }
- | '(' ')' {% ams (sLL $1 $> [])
+ sL1 $1 (DctSingle noExtField (mkLHsSigType tc)) }
+ | '(' ')' {% ams (sLL $1 $> (DctMulti noExtField []))
[mop $1,mcp $2] }
- | '(' deriv_types ')' {% ams (sLL $1 $> $2)
+ | '(' deriv_types ')' {% ams (sLL $1 $> (DctMulti noExtField $2))
[mop $1,mcp $3] }
- -- Glasgow extension: allow partial
- -- applications in derivings
-----------------------------------------------------------------------------
-- Value definitions
=====================================
compiler/GHC/Parser/PostProcess/Haddock.hs
=====================================
@@ -628,15 +628,34 @@ instance HasHaddock (Located (HsDerivingClause GhcPs)) where
Just (L l (ViaStrategy _)) -> (pure (), registerLocHdkA l)
Just (L l _) -> (registerLocHdkA l, pure ())
register_strategy_before
- deriv_clause_tys' <-
- extendHdkA (getLoc deriv_clause_tys) $
- traverse @Located addHaddock deriv_clause_tys
+ deriv_clause_tys' <- addHaddock deriv_clause_tys
register_strategy_after
pure HsDerivingClause
{ deriv_clause_ext = noExtField,
deriv_clause_strategy,
deriv_clause_tys = deriv_clause_tys' }
+-- Process the types in a single deriving clause, which may come in one of the
+-- following forms:
+--
+-- 1. A singular type constructor:
+-- deriving Eq -- ^ Comment on Eq
+--
+-- 2. A list of comma-separated types surrounded by enclosing parentheses:
+-- deriving ( Eq -- ^ Comment on Eq
+-- , C a -- ^ Comment on C a
+-- )
+instance HasHaddock (Located (DerivClauseTys GhcPs)) where
+ addHaddock (L l_dct dct) =
+ extendHdkA l_dct $
+ case dct of
+ DctSingle x ty -> do
+ ty' <- addHaddock ty
+ pure $ L l_dct $ DctSingle x ty'
+ DctMulti x tys -> do
+ tys' <- addHaddock tys
+ pure $ L l_dct $ DctMulti x tys'
+
-- Process a single data constructor declaration, which may come in one of the
-- following forms:
--
=====================================
compiler/GHC/Rename/Module.hs
=====================================
@@ -1895,15 +1895,25 @@ rnLHsDerivingClause doc
(L loc (HsDerivingClause
{ deriv_clause_ext = noExtField
, deriv_clause_strategy = dcs
- , deriv_clause_tys = L loc' dct }))
+ , deriv_clause_tys = dct }))
= do { (dcs', dct', fvs)
- <- rnLDerivStrategy doc dcs $ mapFvRn rn_clause_pred dct
+ <- rnLDerivStrategy doc dcs $ rn_deriv_clause_tys dct
; warnNoDerivStrat dcs' loc
; pure ( L loc (HsDerivingClause { deriv_clause_ext = noExtField
, deriv_clause_strategy = dcs'
- , deriv_clause_tys = L loc' dct' })
+ , deriv_clause_tys = dct' })
, fvs ) }
where
+ rn_deriv_clause_tys :: LDerivClauseTys GhcPs
+ -> RnM (LDerivClauseTys GhcRn, FreeVars)
+ rn_deriv_clause_tys (L l dct) = case dct of
+ DctSingle x ty -> do
+ (ty', fvs) <- rn_clause_pred ty
+ pure (L l (DctSingle x ty'), fvs)
+ DctMulti x tys -> do
+ (tys', fvs) <- mapFvRn rn_clause_pred tys
+ pure (L l (DctMulti x tys'), fvs)
+
rn_clause_pred :: LHsSigType GhcPs -> RnM (LHsSigType GhcRn, FreeVars)
rn_clause_pred pred_ty = do
let inf_err = Just (text "Inferred type variables are not allowed")
=====================================
compiler/GHC/Tc/Deriv.hs
=====================================
@@ -437,17 +437,22 @@ makeDerivSpecs :: [DerivInfo]
-> TcM [EarlyDerivSpec]
makeDerivSpecs deriv_infos deriv_decls
= do { eqns1 <- sequenceA
- [ deriveClause rep_tc scoped_tvs dcs preds err_ctxt
+ [ deriveClause rep_tc scoped_tvs dcs (deriv_clause_preds dct) err_ctxt
| DerivInfo { di_rep_tc = rep_tc
, di_scoped_tvs = scoped_tvs
, di_clauses = clauses
, di_ctxt = err_ctxt } <- deriv_infos
, L _ (HsDerivingClause { deriv_clause_strategy = dcs
- , deriv_clause_tys = L _ preds })
+ , deriv_clause_tys = dct })
<- clauses
]
; eqns2 <- mapM (recoverM (pure Nothing) . deriveStandalone) deriv_decls
; return $ concat eqns1 ++ catMaybes eqns2 }
+ where
+ deriv_clause_preds :: LDerivClauseTys GhcRn -> [LHsSigType GhcRn]
+ deriv_clause_preds (L _ dct) = case dct of
+ DctSingle _ ty -> [ty]
+ DctMulti _ tys -> tys
------------------------------------------------------------------
-- | Process the derived classes in a single @deriving@ clause.
=====================================
compiler/GHC/Tc/Instance/Class.hs
=====================================
@@ -388,10 +388,9 @@ makeLitDict clas ty et
| Just (_, co_dict) <- tcInstNewTyCon_maybe (classTyCon clas) [ty]
-- co_dict :: KnownNat n ~ SNat n
, [ meth ] <- classMethods clas
- , Just tcRep <- tyConAppTyCon_maybe -- SNat
- $ funResultTy -- SNat n
- $ dropForAlls -- KnownNat n => SNat n
- $ idType meth -- forall n. KnownNat n => SNat n
+ , Just tcRep <- tyConAppTyCon_maybe (classMethodTy meth)
+ -- If the method type is forall n. KnownNat n => SNat n
+ -- then tcRep is SNat
, Just (_, co_rep) <- tcInstNewTyCon_maybe tcRep [ty]
-- SNat n ~ Integer
, let ev_tm = mkEvCast et (mkTcSymCo (mkTcTransCo co_dict co_rep))
=====================================
compiler/GHC/Tc/Module.hs
=====================================
@@ -65,9 +65,10 @@ import GHC.Builtin.Types ( unitTy, mkListTy )
import GHC.Driver.Plugins
import GHC.Driver.Session
import GHC.Hs
-import GHC.Iface.Syntax ( ShowSub(..), showToHeader )
-import GHC.Iface.Type ( ShowForAllFlag(..) )
-import GHC.Core.PatSyn( pprPatSynType )
+import GHC.Iface.Syntax ( ShowSub(..), showToHeader )
+import GHC.Iface.Type ( ShowForAllFlag(..) )
+import GHC.Core.PatSyn ( pprPatSynType )
+import GHC.Core.Predicate ( classMethodTy )
import GHC.Builtin.Names
import GHC.Builtin.Utils
import GHC.Types.Name.Reader
@@ -1014,10 +1015,8 @@ checkBootTyCon is_boot tc1 tc2
name2 = idName id2
pname1 = quotes (ppr name1)
pname2 = quotes (ppr name2)
- (_, rho_ty1) = splitForAllTys (idType id1)
- op_ty1 = funResultTy rho_ty1
- (_, rho_ty2) = splitForAllTys (idType id2)
- op_ty2 = funResultTy rho_ty2
+ op_ty1 = classMethodTy id1
+ op_ty2 = classMethodTy id2
eqAT (ATI tc1 def_ats1) (ATI tc2 def_ats2)
= checkBootTyCon is_boot tc1 tc2 `andThenCheck`
=====================================
compiler/GHC/Tc/Solver.hs
=====================================
@@ -1374,7 +1374,7 @@ growThetaTyVars theta tcvs
| otherwise = transCloVarSet mk_next seed_tcvs
where
seed_tcvs = tcvs `unionVarSet` tyCoVarsOfTypes ips
- (ips, non_ips) = partition isIPPred theta
+ (ips, non_ips) = partition isIPLikePred theta
-- See Note [Inheriting implicit parameters] in GHC.Tc.Utils.TcType
mk_next :: VarSet -> VarSet -- Maps current set to newly-grown ones
=====================================
compiler/GHC/Tc/Solver/Canonical.hs
=====================================
@@ -29,7 +29,7 @@ import GHC.Core.Multiplicity
import GHC.Core.TyCo.Rep -- cleverly decomposes types, good for completeness checking
import GHC.Core.Coercion
import GHC.Core
-import GHC.Types.Id( idType, mkTemplateLocals )
+import GHC.Types.Id( mkTemplateLocals )
import GHC.Core.FamInstEnv ( FamInstEnvs )
import GHC.Tc.Instance.Family ( tcTopNormaliseNewTypeTF_maybe )
import GHC.Types.Var
@@ -542,7 +542,7 @@ mk_strict_superclasses rec_clss (CtGiven { ctev_evar = evar, ctev_loc = loc })
mk_given_desc sel_id sc_pred
; mk_superclasses rec_clss given_ev tvs theta sc_pred }
where
- sc_pred = funResultTy (piResultTys (idType sel_id) tys)
+ sc_pred = classMethodInstTy sel_id tys
-- See Note [Nested quantified constraint superclasses]
mk_given_desc :: Id -> PredType -> (PredType, EvTerm)
=====================================
compiler/GHC/Tc/Solver/Interact.hs
=====================================
@@ -566,10 +566,10 @@ solveOneFromTheOther ev_i ev_w
ev_id_w = ctEvEvId ev_w
different_level_strategy -- Both Given
- | isIPPred pred = if lvl_w > lvl_i then KeepWork else KeepInert
- | otherwise = if lvl_w > lvl_i then KeepInert else KeepWork
+ | isIPLikePred pred = if lvl_w > lvl_i then KeepWork else KeepInert
+ | otherwise = if lvl_w > lvl_i then KeepInert else KeepWork
-- See Note [Replacement vs keeping] (the different-level bullet)
- -- For the isIPPred case see Note [Shadowing of Implicit Parameters]
+ -- For the isIPLikePred case see Note [Shadowing of Implicit Parameters]
same_level_strategy binds -- Both Given
| GivenOrigin (InstSC s_i) <- ctLocOrigin loc_i
@@ -1071,6 +1071,8 @@ shortCutSolver dflags ev_w ev_i
-- programs should typecheck regardless of whether we take this step or
-- not. See Note [Shortcut solving]
+ && not (isIPLikePred (ctEvPred ev_w)) -- Not for implicit parameters (#18627)
+
&& not (xopt LangExt.IncoherentInstances dflags)
-- If IncoherentInstances is on then we cannot rely on coherence of proofs
-- in order to justify this optimization: The proof provided by the
@@ -1079,6 +1081,7 @@ shortCutSolver dflags ev_w ev_i
&& gopt Opt_SolveConstantDicts dflags
-- Enabled by the -fsolve-constant-dicts flag
+
= do { ev_binds_var <- getTcEvBindsVar
; ev_binds <- ASSERT2( not (isCoEvBindsVar ev_binds_var ), ppr ev_w )
getTcEvBindsMap ev_binds_var
=====================================
compiler/GHC/Tc/Solver/Monad.hs
=====================================
@@ -2527,8 +2527,7 @@ emptyDictMap = emptyTcAppMap
findDict :: DictMap a -> CtLoc -> Class -> [Type] -> Maybe a
findDict m loc cls tys
- | isCTupleClass cls
- , any hasIPPred tys -- See Note [Tuples hiding implicit parameters]
+ | hasIPSuperClasses cls tys -- See Note [Tuples hiding implicit parameters]
= Nothing
| Just {} <- isCallStackPred cls tys
=====================================
compiler/GHC/Tc/TyCl/Instance.hs
=====================================
@@ -54,6 +54,7 @@ import GHC.Core.Make ( nO_METHOD_BINDING_ERROR_ID )
import GHC.Core.Unfold.Make ( mkInlineUnfoldingWithArity, mkDFunUnfolding )
import GHC.Core.Type
import GHC.Core.SimpleOpt
+import GHC.Core.Predicate( classMethodInstTy )
import GHC.Tc.Types.Evidence
import GHC.Core.TyCon
import GHC.Core.Coercion.Axiom
@@ -1634,7 +1635,7 @@ tcMethods dfun_id clas tyvars dfun_ev_vars inst_tys
nO_METHOD_BINDING_ERROR_ID
error_msg dflags = L inst_loc (HsLit noExtField (HsStringPrim NoSourceText
(unsafeMkByteString (error_string dflags))))
- meth_tau = funResultTy (piResultTys (idType sel_id) inst_tys)
+ meth_tau = classMethodInstTy sel_id inst_tys
error_string dflags = showSDoc dflags
(hcat [ppr inst_loc, vbar, ppr sel_id ])
lam_wrapper = mkWpTyLams tyvars <.> mkWpLams dfun_ev_vars
=====================================
compiler/GHC/Tc/Utils/TcType.hs
=====================================
@@ -79,7 +79,7 @@ module GHC.Tc.Utils.TcType (
isFloatingTy, isDoubleTy, isFloatTy, isIntTy, isWordTy, isStringTy,
isIntegerTy, isNaturalTy,
isBoolTy, isUnitTy, isCharTy, isCallStackTy, isCallStackPred,
- hasIPPred, isTauTy, isTauTyCon, tcIsTyVarTy, tcIsForAllTy,
+ isTauTy, isTauTyCon, tcIsTyVarTy, tcIsForAllTy,
isPredTy, isTyVarClassPred, isTyVarHead, isInsolubleOccursCheck,
checkValidClsArgs, hasTyVarHead,
isRigidTy, isAlmostFunctionFree,
@@ -141,7 +141,7 @@ module GHC.Tc.Utils.TcType (
mkTyConTy, mkTyVarTy, mkTyVarTys,
mkTyCoVarTy, mkTyCoVarTys,
- isClassPred, isEqPrimPred, isIPPred, isEqPred, isEqPredClass,
+ isClassPred, isEqPrimPred, isIPLikePred, isEqPred, isEqPredClass,
mkClassPred,
tcSplitDFunTy, tcSplitDFunHead, tcSplitMethodTy,
isRuntimeRepVar, isKindLevPoly,
@@ -1747,7 +1747,7 @@ pickCapturedPreds
pickCapturedPreds qtvs theta
= filter captured theta
where
- captured pred = isIPPred pred || (tyCoVarsOfType pred `intersectsVarSet` qtvs)
+ captured pred = isIPLikePred pred || (tyCoVarsOfType pred `intersectsVarSet` qtvs)
-- Superclasses
=====================================
compiler/GHC/ThToHs.hs
=====================================
@@ -1393,12 +1393,25 @@ cvtContext p tys = do { preds' <- mapM cvtPred tys
cvtPred :: TH.Pred -> CvtM (LHsType GhcPs)
cvtPred = cvtType
+cvtDerivClauseTys :: TH.Cxt -> CvtM (LDerivClauseTys GhcPs)
+cvtDerivClauseTys tys
+ = do { tys' <- mapM cvtType tys
+ -- Since TH.Cxt doesn't indicate the presence or absence of
+ -- parentheses in a deriving clause, we have to choose between
+ -- DctSingle and DctMulti somewhat arbitrarily. We opt to use DctMulti
+ -- unless the TH.Cxt is a singleton list whose type is a bare type
+ -- constructor with no arguments.
+ ; case tys' of
+ [ty'@(L l (HsTyVar _ NotPromoted _))]
+ -> return $ L l $ DctSingle noExtField $ mkLHsSigType ty'
+ _ -> returnL $ DctMulti noExtField (map mkLHsSigType tys') }
+
cvtDerivClause :: TH.DerivClause
-> CvtM (LHsDerivingClause GhcPs)
-cvtDerivClause (TH.DerivClause ds ctxt)
- = do { ctxt' <- fmap (map mkLHsSigType) <$> cvtContext appPrec ctxt
- ; ds' <- traverse cvtDerivStrategy ds
- ; returnL $ HsDerivingClause noExtField ds' ctxt' }
+cvtDerivClause (TH.DerivClause ds tys)
+ = do { tys' <- cvtDerivClauseTys tys
+ ; ds' <- traverse cvtDerivStrategy ds
+ ; returnL $ HsDerivingClause noExtField ds' tys' }
cvtDerivStrategy :: TH.DerivStrategy -> CvtM (Hs.LDerivStrategy GhcPs)
cvtDerivStrategy TH.StockStrategy = returnL Hs.StockStrategy
=====================================
docs/users_guide/phases.rst
=====================================
@@ -1028,7 +1028,7 @@ for example).
This option affects the processing of RTS control options given
either on the command line or via the :envvar:`GHCRTS` environment
- variable. There are three possibilities:
+ variable. There are five possibilities:
``-rtsopts=none``
Disable all processing of RTS options. If ``+RTS`` appears
=====================================
testsuite/tests/simplCore/should_compile/T18649.hs
=====================================
@@ -0,0 +1,26 @@
+{-# LANGUAGE ImplicitParams #-}
+{-# LANGUAGE ConstraintKinds #-}
+{-# LANGUAGE FlexibleContexts #-}
+
+module Test where
+
+import Prelude
+
+type Hidden a =
+ ( ?enable :: a
+ , Eq a -- removing this "fixes" the issue
+ )
+
+{-# NOINLINE a #-}
+a :: Hidden Bool => Integer -> Bool
+a _ = ?enable
+
+system :: Hidden Bool => Bool
+system = a 0
+
+topEntity :: Bool -> Bool
+topEntity ena = let ?enable = ena
+ in system
+
+someVar = let ?enable = True
+ in system
=====================================
testsuite/tests/simplCore/should_compile/T18649.stderr
=====================================
@@ -0,0 +1,4 @@
+
+==================== Tidy Core rules ====================
+
+
=====================================
testsuite/tests/simplCore/should_compile/all.T
=====================================
@@ -333,3 +333,7 @@ test('T18347', normal, compile, ['-dcore-lint -O'])
test('T18355', [ grep_errmsg(r'OneShot') ], compile, ['-O -ddump-simpl -dsuppress-uniques'])
test('T18399', normal, compile, ['-dcore-lint -O'])
test('T18589', normal, compile, ['-dcore-lint -O'])
+
+# T18649 should /not/ generate a specialisation rule
+test('T18649', normal, compile, ['-O -ddump-rules -Wno-simplifiable-class-constraints'])
+
=====================================
testsuite/tests/typecheck/should_run/T18627.hs
=====================================
@@ -0,0 +1,16 @@
+{-# LANGUAGE DataKinds #-}
+{-# LANGUAGE ImplicitParams #-}
+{-# LANGUAGE MultiParamTypeClasses #-}
+module Main where
+
+import GHC.Classes
+
+instance IP "x" Int where
+ ip = 21
+
+baz :: (?x :: Int) => Int
+baz = ?x
+
+main :: IO ()
+main = let ?x = 42
+ in print baz
=====================================
testsuite/tests/typecheck/should_run/T18627.stdout
=====================================
@@ -0,0 +1 @@
+42
=====================================
testsuite/tests/typecheck/should_run/all.T
=====================================
@@ -146,3 +146,4 @@ test('UnliftedNewtypesDependentFamilyRun', normal, compile_and_run, [''])
test('UnliftedNewtypesIdentityRun', normal, compile_and_run, [''])
test('UnliftedNewtypesCoerceRun', normal, compile_and_run, [''])
test('T17104', normal, compile_and_run, [''])
+test('T18627', normal, compile_and_run, ['-O']) # Optimisation shows up the bug
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/ac3f506ade42880089957bf5c3ec2e5154d037c6...15748dcb170fab11d975b501baafc0ab61b98bdb
--
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/ac3f506ade42880089957bf5c3ec2e5154d037c6...15748dcb170fab11d975b501baafc0ab61b98bdb
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