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[Git][ghc/ghc][wip/T26961] Add Data.RealFloat and Infinity/NegInfinity/NaN pattern synonyms (#26961)
by Brandon Chinn (＠brandonchinn178) 23 Aug '26

23 Aug '26

Brandon Chinn pushed to branch wip/T26961 at Glasgow Haskell Compiler / GHC Commits: 93a67fe4 by Brandon Chinn at 2026-08-22T10:11:56-07:00 Add Data.RealFloat and Infinity/NegInfinity/NaN pattern synonyms (#26961) - - - - - 6 changed files: - libraries/base/base.cabal.in - libraries/base/changelog.md - + libraries/base/src/Data/RealFloat.hs - testsuite/tests/interface-stability/base-exports.stdout - testsuite/tests/interface-stability/base-exports.stdout-javascript-unknown-ghcjs - testsuite/tests/interface-stability/base-exports.stdout-mingw32 Changes: ===================================== libraries/base/base.cabal.in ===================================== @@ -117,6 +117,7 @@ Library , Data.Monoid , Data.Ord , Data.Proxy + , Data.RealFloat , Data.STRef , Data.STRef.Strict , Data.String ===================================== libraries/base/changelog.md ===================================== @@ -9,6 +9,8 @@ * Introduce `Data.Double` and `Data.Float` modules. ([CLC proposal #378](https://github.com/haskell/core-libraries-committee/issues/378)) * Change `Generically a`'s `Monoid` definition to require a `Semigroup` constraint, and define its `mconcat` using `(<>)` from that constraint. ([CLC proposal #413](https://github.com/haskell/core-libraries-committee/issues/413)) * Add `withEmptyCallStack` to `GHC.Stack`. ([CLC proposal #428](https://github.com/haskell/core-libraries-committee/issues/428)) + * Add new `Data.RealFloat` module re-exporting `RealFloat` from `GHC.Float` ([CLC proposal #394](https://github.com/haskell/core-libraries-committee/issues/394)) + * Add `Infinity`, `NegInfinity`, and `NaN` pattern synonyms to `Data.RealFloat` ([CLC proposal #394](https://github.com/haskell/core-libraries-committee/issues/394)) ## 4.23.0.0 *TBA* * Add `System.IO.hGetNewlineMode`. ([CLC proposal #370](https://github.com/haskell/core-libraries-committee/issues/370)) ===================================== libraries/base/src/Data/RealFloat.hs ===================================== @@ -0,0 +1,59 @@ +{-# LANGUAGE CPP #-} +{-# LANGUAGE PatternSynonyms #-} +{-# LANGUAGE Safe #-} +{-# LANGUAGE ViewPatterns #-} + +-- | +-- +-- Module : Data.RealFloat +-- Copyright : (c) The University of Glasgow 2026 +-- License : BSD-style (see the file libraries/base/LICENSE) +-- +-- Maintainer : libraries(a)haskell.org +-- Stability : stable +-- Portability : portable +-- + +module Data.RealFloat ( + RealFloat (..), + + -- * Infinity + NaN + pattern Infinity, + pattern NegInfinity, + pattern NaN, +) where + +import Data.Bool (Bool (..), (&&)) +import GHC.Internal.Data.Ord ((<), (>)) +import GHC.Internal.Float (RealFloat (..)) +import GHC.Internal.Real ((/)) +#if __GLASGOW_HASKELL__ >= 1001 +import qualified GHC.Essentials as Rebindable +#endif + +pattern Infinity :: (RealFloat a) => a +pattern Infinity <- ((\x -> isInfinite x && x > 0) -> True) where Infinity = 1/0 + +-- | Negative infinity +-- +-- Provided for convenience. Could also use the following instead: +-- * Pattern matching: @(negate -> Infinity)@ +-- * Expressions: @-Infinity@ +pattern NegInfinity :: (RealFloat a) => a +pattern NegInfinity <- ((\x -> isInfinite x && x < 0) -> True) where NegInfinity = -1/0 + +-- | A pattern synonym for NaN values. +-- +-- Note: Per IEEE 754, NaN is never equal to itself, thus these two snippets +-- have different behavior: +-- +-- @ +-- -- foo1 NaN == "a" +-- foo1 NaN = "a" +-- foo1 _ = "b" +-- +-- -- foo2 NaN == "b" +-- foo2 x = if x == NaN then "a" else "b" +-- @ +pattern NaN :: (RealFloat a) => a +pattern NaN <- (isNaN -> True) where NaN = 0/0 ===================================== testsuite/tests/interface-stability/base-exports.stdout ===================================== @@ -1626,6 +1626,29 @@ module Data.Ratio where denominator :: forall a. Ratio a -> a numerator :: forall a. Ratio a -> a +module Data.RealFloat where + -- Safety: Safe + pattern Infinity :: forall a. RealFloat a => a + pattern NaN :: forall a. RealFloat a => a + pattern NegInfinity :: forall a. RealFloat a => a + type RealFloat :: * -> Constraint + class (GHC.Internal.Real.RealFrac a, GHC.Internal.Float.Floating a) => RealFloat a where + floatRadix :: a -> GHC.Internal.Bignum.Integer.Integer + floatDigits :: a -> GHC.Internal.Types.Int + floatRange :: a -> (GHC.Internal.Types.Int, GHC.Internal.Types.Int) + decodeFloat :: a -> (GHC.Internal.Bignum.Integer.Integer, GHC.Internal.Types.Int) + encodeFloat :: GHC.Internal.Bignum.Integer.Integer -> GHC.Internal.Types.Int -> a + exponent :: a -> GHC.Internal.Types.Int + significand :: a -> a + scaleFloat :: GHC.Internal.Types.Int -> a -> a + isNaN :: a -> GHC.Internal.Types.Bool + isInfinite :: a -> GHC.Internal.Types.Bool + isDenormalized :: a -> GHC.Internal.Types.Bool + isNegativeZero :: a -> GHC.Internal.Types.Bool + isIEEE :: a -> GHC.Internal.Types.Bool + atan2 :: a -> a -> a + {-# MINIMAL floatRadix, floatDigits, floatRange, decodeFloat, encodeFloat, isNaN, isInfinite, isDenormalized, isNegativeZero, isIEEE #-} + module Data.STRef where -- Safety: Safe type role STRef nominal representational ===================================== testsuite/tests/interface-stability/base-exports.stdout-javascript-unknown-ghcjs ===================================== @@ -1626,6 +1626,29 @@ module Data.Ratio where denominator :: forall a. Ratio a -> a numerator :: forall a. Ratio a -> a +module Data.RealFloat where + -- Safety: Safe + pattern Infinity :: forall a. RealFloat a => a + pattern NaN :: forall a. RealFloat a => a + pattern NegInfinity :: forall a. RealFloat a => a + type RealFloat :: * -> Constraint + class (GHC.Internal.Real.RealFrac a, GHC.Internal.Float.Floating a) => RealFloat a where + floatRadix :: a -> GHC.Internal.Bignum.Integer.Integer + floatDigits :: a -> GHC.Internal.Types.Int + floatRange :: a -> (GHC.Internal.Types.Int, GHC.Internal.Types.Int) + decodeFloat :: a -> (GHC.Internal.Bignum.Integer.Integer, GHC.Internal.Types.Int) + encodeFloat :: GHC.Internal.Bignum.Integer.Integer -> GHC.Internal.Types.Int -> a + exponent :: a -> GHC.Internal.Types.Int + significand :: a -> a + scaleFloat :: GHC.Internal.Types.Int -> a -> a + isNaN :: a -> GHC.Internal.Types.Bool + isInfinite :: a -> GHC.Internal.Types.Bool + isDenormalized :: a -> GHC.Internal.Types.Bool + isNegativeZero :: a -> GHC.Internal.Types.Bool + isIEEE :: a -> GHC.Internal.Types.Bool + atan2 :: a -> a -> a + {-# MINIMAL floatRadix, floatDigits, floatRange, decodeFloat, encodeFloat, isNaN, isInfinite, isDenormalized, isNegativeZero, isIEEE #-} + module Data.STRef where -- Safety: Safe type role STRef nominal representational ===================================== testsuite/tests/interface-stability/base-exports.stdout-mingw32 ===================================== @@ -1626,6 +1626,29 @@ module Data.Ratio where denominator :: forall a. Ratio a -> a numerator :: forall a. Ratio a -> a +module Data.RealFloat where + -- Safety: Safe + pattern Infinity :: forall a. RealFloat a => a + pattern NaN :: forall a. RealFloat a => a + pattern NegInfinity :: forall a. RealFloat a => a + type RealFloat :: * -> Constraint + class (GHC.Internal.Real.RealFrac a, GHC.Internal.Float.Floating a) => RealFloat a where + floatRadix :: a -> GHC.Internal.Bignum.Integer.Integer + floatDigits :: a -> GHC.Internal.Types.Int + floatRange :: a -> (GHC.Internal.Types.Int, GHC.Internal.Types.Int) + decodeFloat :: a -> (GHC.Internal.Bignum.Integer.Integer, GHC.Internal.Types.Int) + encodeFloat :: GHC.Internal.Bignum.Integer.Integer -> GHC.Internal.Types.Int -> a + exponent :: a -> GHC.Internal.Types.Int + significand :: a -> a + scaleFloat :: GHC.Internal.Types.Int -> a -> a + isNaN :: a -> GHC.Internal.Types.Bool + isInfinite :: a -> GHC.Internal.Types.Bool + isDenormalized :: a -> GHC.Internal.Types.Bool + isNegativeZero :: a -> GHC.Internal.Types.Bool + isIEEE :: a -> GHC.Internal.Types.Bool + atan2 :: a -> a -> a + {-# MINIMAL floatRadix, floatDigits, floatRange, decodeFloat, encodeFloat, isNaN, isInfinite, isDenormalized, isNegativeZero, isIEEE #-} + module Data.STRef where -- Safety: Safe type role STRef nominal representational View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/93a67fe4acd08a1ab434c8f0f10983a… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/93a67fe4acd08a1ab434c8f0f10983a… You're receiving this email because of your account on gitlab.haskell.org. 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[Git][ghc/ghc] Pushed new branch wip/sjakobi/ci-demote-aarch64-linux-fastci
by Simon Jakobi (＠sjakobi) 22 Aug '26

22 Aug '26

Simon Jakobi pushed new branch wip/sjakobi/ci-demote-aarch64-linux-fastci at Glasgow Haskell Compiler / GHC -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/tree/wip/sjakobi/ci-demote-aarch64-lin… You're receiving this email because of your account on gitlab.haskell.org. Manage all notifications: https://gitlab.haskell.org/-/profile/notifications | Help: https://gitlab.haskell.org/help

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[Git][ghc/ghc][wip/sjakobi/T27459] Sort the unifiers in getCoherentUnifiers
by Simon Jakobi (＠sjakobi) 22 Aug '26

22 Aug '26

Simon Jakobi pushed to branch wip/sjakobi/T27459 at Glasgow Haskell Compiler / GHC Commits: 125d9c16 by Simon Jakobi at 2026-08-22T17:03:19+02:00 Sort the unifiers in getCoherentUnifiers Enumerating the unifiers non-deterministically (62cc6594f5e) exposed unique-dependent instance order to every consumer of the full list. The error-message sites re-sort for display, but Template Haskell's reifyInstances (and lookupThInstName) passed the list on unsorted, so a splice reifying instances at a type variable could generate code in unique-dependent order — an ABI-relevant leak. Sort in getCoherentUnifiers itself, so every external consumer gets a deterministic order. The internal construction sites keep the lazy, unsorted list via the unexported nonDetCoherentUnifiers. See Note [Matches vs Unifiers] in GHC.Core.RoughMap. Also add determ026, which reifies the Show instances at a type variable under two different unique supplies and compares the output. It fails without the sort. Context: #27459 Assisted-by: Claude Fable 5 - - - - - 5 changed files: - compiler/GHC/Core/InstEnv.hs - compiler/GHC/Core/RoughMap.hs - + testsuite/tests/determinism/determ026/A.hs - + testsuite/tests/determinism/determ026/Makefile - + testsuite/tests/determinism/determ026/all.T Changes: ===================================== compiler/GHC/Core/InstEnv.hs ===================================== @@ -53,6 +53,8 @@ import GHC.Types.Name import GHC.Types.Name.Set import GHC.Types.Id import GHC.Generics (Generic) +import Data.Function ( on ) +import Data.List ( sortBy ) import Data.List.NonEmpty ( NonEmpty (..), nonEmpty ) import qualified Data.List.NonEmpty as NE import Data.Maybe ( isJust ) @@ -1122,6 +1124,9 @@ data PotentialUnifiers -- printing an error message. It can be expensive to compute all -- the unifiers because if you are matching something like C a[sk] then -- all instances will unify. + -- CQ-REF[coherent-unifiers-sort] + -- D~ "when printing an error message" is incomplete: TH's + -- reifyInstances also consumes the full list. {- Note [Recording coherence information in `PotentialUnifiers`] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -1167,11 +1172,24 @@ instance Semigroup PotentialUnifiers where NoUnifiers c1 <> NoUnifiers c2 = NoUnifiers (c1 `andCanEv` c2) NoUnifiers _ <> u = u OneOrMoreUnifiers (unifier :| unifiers) <> u - = OneOrMoreUnifiers (unifier :| (unifiers <> getCoherentUnifiers u)) - + = OneOrMoreUnifiers (unifier :| (unifiers <> nonDetCoherentUnifiers u)) + +-- CQ[coherent-unifiers-sort] +-- Q: Why does the exported accessor sort, and why is there a raw +-- (non-deterministic, unexported) variant? +-- A~ The unifiers are enumerated in non-deterministic order (see +-- Note [Matches vs Unifiers] in GHC.Core.RoughMap). Sorting here makes +-- the order deterministic for every external consumer (error messages, +-- TH's reifyInstances). The internal construction sites (the Semigroup +-- instance, add_unifier) must use the raw variant: they build the list +-- incrementally, and sorting a partial list would both be wasted work +-- and force the lazily-enumerated tail. getCoherentUnifiers :: PotentialUnifiers -> [ClsInst] -getCoherentUnifiers NoUnifiers{} = [] -getCoherentUnifiers (OneOrMoreUnifiers cls) = NE.toList cls +getCoherentUnifiers = sortBy (stableNameCmp `on` is_dfun_name) . nonDetCoherentUnifiers + +nonDetCoherentUnifiers :: PotentialUnifiers -> [ClsInst] +nonDetCoherentUnifiers NoUnifiers{} = [] +nonDetCoherentUnifiers (OneOrMoreUnifiers cls) = NE.toList cls -- | Are there no *coherent* unifiers? nullUnifiers :: PotentialUnifiers -> Bool @@ -1262,7 +1280,7 @@ instEnvMatchesAndUnifiers (InstEnv rm) vis_mods cls tys -- Note [Coherence and specialisation: overview] add_unifier item other_unifiers | not (isIncoherent item) - = OneOrMoreUnifiers (item :| getCoherentUnifiers other_unifiers) + = OneOrMoreUnifiers (item :| nonDetCoherentUnifiers other_unifiers) -- So `item` is incoherent; see Note [Incoherent instances] | otherwise ===================================== compiler/GHC/Core/RoughMap.hs ===================================== @@ -172,12 +172,19 @@ For the same reason the unifiers are enumerated in non-deterministic order (see the RML_WildCard case of lookupRM'): a deterministic fold would have to inspect every entry of rm_known before it could produce the first unifier, defeating that laziness (#27459; see Note [Cost of deterministic iteration] in -GHC.Types.Unique.DFM). The order is observable only where error messages are -rendered, so those sites must sort the unifiers they display; see -fuzzyClsInstCmp in GHC.Core.InstEnv and reportConflictInstErr in -GHC.Tc.Instance.Family. The matches, by contrast, are still enumerated +GHC.Types.Unique.DFM). The matches, by contrast, are still enumerated deterministically. +CQ[unifier-order-consumers] +Q: Where does the non-deterministic unifier order become user-visible, and + who restores determinism? +A~ Wherever the full list is consumed: class-instance consumers (error + messages, TH's reifyInstances — see #27459 review finding) all go through + getCoherentUnifiers in GHC.Core.InstEnv, which sorts; family-instance + conflicts are sorted where displayed, see reportConflictInstErr in + GHC.Tc.Instance.Family. Consumers that only test emptiness (the hot + paths) never observe the order. + Note [Simple Matching Semantics] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Suppose `rm` is a RoughMap representing a set of (key,vals) pairs, ===================================== testsuite/tests/determinism/determ026/A.hs ===================================== @@ -0,0 +1,24 @@ +{-# LANGUAGE TemplateHaskell #-} +module A where + +-- reifyInstances at a bare type variable returns the unifying instances, +-- whose order must not depend on the order of Uniques (#27459). +-- +-- The printed heads avoid pprint/show of anything containing a NameU: +-- those embed uniques and would differ between the two runs regardless +-- of instance order. + +import Language.Haskell.TH + +$(do let headName :: Type -> String + headName (AppT f _) = headName f + headName (ConT n) = show n + headName ListT = "[]" + headName (TupleT i) = "Tuple" ++ show i + headName ArrowT = "->" + headName _ = "<other-type>" + instHead (InstanceD _ _ (AppT _ arg) _) = headName arg + instHead _ = "<other-dec>" + insts <- reifyInstances ''Show [VarT (mkName "a")] + runIO (mapM_ (putStrLn . instHead) insts) + return []) ===================================== testsuite/tests/determinism/determ026/Makefile ===================================== @@ -0,0 +1,13 @@ +TOP=../../.. +include $(TOP)/mk/boilerplate.mk +include $(TOP)/mk/test.mk + +# Check that the instance order returned by TH's reifyInstances doesn't +# depend on the order of Uniques (#27459): run a splice that prints the +# instances with two unique supplies and compare the output. +determ026: + $(RM) A.hi A.o + '$(TEST_HC)' $(TEST_HC_OPTS) -v0 -dinitial-unique=0 -dunique-increment=1 A.hs > A.out.normal + $(RM) A.hi A.o + '$(TEST_HC)' $(TEST_HC_OPTS) -v0 -dinitial-unique=16777215 -dunique-increment=-1 A.hs > A.out.reversed + diff A.out.normal A.out.reversed ===================================== testsuite/tests/determinism/determ026/all.T ===================================== @@ -0,0 +1,3 @@ +test('determ026', + [extra_files(['A.hs']), req_th], + makefile_test, ['determ026']) View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/125d9c16c79ebccfb8f516b69c04cca… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/125d9c16c79ebccfb8f516b69c04cca… You're receiving this email because of your account on gitlab.haskell.org. 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[Git][ghc/ghc][wip/sjakobi/T16836-implicit-field-strictness] Add -Wimplicit-field-strictness (#16836)
by Simon Jakobi (＠sjakobi) 22 Aug '26

22 Aug '26

Simon Jakobi pushed to branch wip/sjakobi/T16836-implicit-field-strictness at Glasgow Haskell Compiler / GHC Commits: 5bade2e3 by Simon Jakobi at 2026-08-22T15:58:42+02:00 Add -Wimplicit-field-strictness (#16836) This opt-in warning fires when a data constructor field lacks an explicit strictness annotation (`!` or `~`). It complements the LazyFieldAnnotations extension (4762a8bf30f) from GHC proposal 752, which makes `~` annotations available for this purpose. Deciding which fields to report requires their levity, so the check runs after typechecking. To keep the noise down, the diagnostic is emitted once per data declaration, grouped by constructor. Closes #16836. Assisted-by: Claude Fable 5 - - - - - 20 changed files: - + changelog.d/implicit-field-strictness-warning - changelog.d/lazy-field-annotations - compiler/GHC/Driver/Flags.hs - compiler/GHC/Driver/Session.hs - compiler/GHC/Tc/Errors/Ppr.hs - compiler/GHC/Tc/Errors/Types.hs - compiler/GHC/Tc/TyCl.hs - compiler/GHC/Types/Error/Codes.hs - compiler/GHC/Types/Hint.hs - compiler/GHC/Types/Hint/Ppr.hs - docs/users_guide/exts/strict.rst - docs/users_guide/using-warnings.rst - + testsuite/tests/warnings/should_compile/T16836a.hs - + testsuite/tests/warnings/should_compile/T16836a.stderr - + testsuite/tests/warnings/should_compile/T16836b.hs - + testsuite/tests/warnings/should_compile/T16836c.hs - + testsuite/tests/warnings/should_compile/T16836c.stderr - + testsuite/tests/warnings/should_compile/T16836d.hs - + testsuite/tests/warnings/should_compile/T16836d.stderr - testsuite/tests/warnings/should_compile/all.T Changes: ===================================== changelog.d/implicit-field-strictness-warning ===================================== @@ -0,0 +1,10 @@ +section: compiler +synopsis: Add `-Wimplicit-field-strictness` +issues: #16836 +mrs: !16555 + +description: { + The new opt-in warning :ghc-flag:`-Wimplicit-field-strictness` reports + data constructor fields that lack an explicit strictness annotation + (``!`` or ``~``). +} ===================================== changelog.d/lazy-field-annotations ===================================== @@ -11,4 +11,7 @@ description: { continues to control the default strictness of unannotated fields. See `GHC Proposal #752 <https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0752-l…>`_. + + Also note the new opt-in :ghc-flag:`-Wimplicit-field-strictness` warning, which + reports fields lacking an explicit annotation. } ===================================== compiler/GHC/Driver/Flags.hs ===================================== @@ -1142,6 +1142,7 @@ data WarningFlag = | Opt_WarnUnrecognisedModifiers -- ^ @since 10.0 | Opt_WarnSemaphoreOpenFailure -- Since 10.0.1 | Opt_WarnDefaultedCallStack -- ^ @since 10.2 + | Opt_WarnImplicitFieldStrictness -- ^ @since 10.2 deriving (Eq, Ord, Show, Enum, Bounded) -- | Return the names of a WarningFlag @@ -1251,6 +1252,7 @@ warnFlagNames wflag = case wflag of Opt_WarnTypeEqualityRequiresOperators -> "type-equality-requires-operators" :| [] Opt_WarnMissingRoleAnnotations -> "missing-role-annotations" :| [] Opt_WarnImplicitRhsQuantification -> "implicit-rhs-quantification" :| [] + Opt_WarnImplicitFieldStrictness -> "implicit-field-strictness" :| [] Opt_WarnIncompleteExportWarnings -> "incomplete-export-warnings" :| [] Opt_WarnIncompleteRecordSelectors -> "incomplete-record-selectors" :| [] Opt_WarnBadlyLevelledTypes -> "badly-levelled-types" :| [] ===================================== compiler/GHC/Driver/Session.hs ===================================== @@ -2449,6 +2449,7 @@ wWarningFlagsDeps = [minBound..maxBound] >>= \x -> case x of Opt_WarnUnrecognisedModifiers -> warnSpec x Opt_WarnSemaphoreOpenFailure -> warnSpec x Opt_WarnDefaultedCallStack -> warnSpec x + Opt_WarnImplicitFieldStrictness -> warnSpec x warningGroupsDeps :: [(Deprecation, FlagSpec WarningGroup)] warningGroupsDeps = map mk warningGroups ===================================== compiler/GHC/Tc/Errors/Ppr.hs ===================================== @@ -1384,6 +1384,21 @@ instance Diagnostic TcRnMessage where hang (text "Missing role annotation" <> colon) 2 (text "type role" <+> ppr name <+> hsep (map ppr roles)) + TcRnImplicitFieldStrictness _lazy_anns cons -> mkSimpleDecorated $ + hang (text "These constructor fields lack an explicit strictness annotation" <> colon) + 2 (vcat (map ppr_con (NE.toList cons))) + where + ppr_con (con, fields) = + bullet <+> text "In" <+> quotes (ppr con) <> colon <+> ppr_fields (NE.toList fields) + ppr_fields fields + | let names = [n | ImplicitStrictnessRecField n <- fields] + , not (null names) + = text "field" <> plural names <+> quotedListWithAnd (map ppr names) + | otherwise + = let poss = [i | ImplicitStrictnessPosField i <- fields] + in text "field" <> plural poss + <+> unquotedListWith (text "and") (map int poss) + TcRnIllformedTypePattern p -> mkSimpleDecorated $ hang (text "Ill-formed type pattern:") 2 (ppr p) @@ -2693,6 +2708,8 @@ instance Diagnostic TcRnMessage where -> ErrorWithoutFlag TcRnMissingRoleAnnotation{} -> WarningWithFlag Opt_WarnMissingRoleAnnotations + TcRnImplicitFieldStrictness{} + -> WarningWithFlag Opt_WarnImplicitFieldStrictness TcRnIllegalInvisTyVarBndr{} -> ErrorWithoutFlag TcRnIllegalWildcardTyVarBndr{} @@ -3428,6 +3445,12 @@ instance Diagnostic TcRnMessage where -> noHints TcRnMissingRoleAnnotation{} -> noHints + TcRnImplicitFieldStrictness lazy_anns _ + -> SuggestExplicitFieldStrictness + : [ useExtensionInOrderTo + (text "to allow" <+> quotes (char '~') <+> text "annotations") + LangExt.LazyFieldAnnotations + | not lazy_anns ] TcRnIllegalInvisTyVarBndr{} -> [suggestExtension LangExt.TypeAbstractions] TcRnIllegalWildcardTyVarBndr{} ===================================== compiler/GHC/Tc/Errors/Types.hs ===================================== @@ -123,6 +123,7 @@ module GHC.Tc.Errors.Types ( , TypeSyntax(..) , typeSyntaxExtension , SuggestLinear(..) + , ImplicitStrictnessField(..) -- * Errors for hs-boot and signature files , BadBootDecls(..) @@ -4235,6 +4236,23 @@ data TcRnMessage where -} TcRnMissingRoleAnnotation :: Name -> [Role] -> TcRnMessage + + {-| TcRnImplicitFieldStrictness is a warning that occurs when a data + constructor field lacks an explicit strictness annotation (@!@ or @~@) + + Controlled by flags: + - Wimplicit-field-strictness + + Test cases: + T16836a, T16836b, T16836c, T16836d + + -} + TcRnImplicitFieldStrictness + :: Bool -- ^ whether @LazyFieldAnnotations@ is enabled + -> NonEmpty (Name, NonEmpty ImplicitStrictnessField) + -- ^ per data constructor, the fields lacking annotations + -> TcRnMessage + {-| TcRnPatersonCondFailure is an error that occurs when an instance declaration fails to conform to the Paterson conditions. Which particular condition fails depends on the constructor of PatersonCondFailure @@ -6399,6 +6417,14 @@ data PatSynInvalidRhsReason | PatSynUnboundVar !Name deriving (Generic) +-- | A constructor field lacking an explicit strictness annotation, as +-- reported by 'TcRnImplicitFieldStrictness'. +data ImplicitStrictnessField + -- | A record field + = ImplicitStrictnessRecField FieldLabelString + -- | A positional argument (1-based index) + | ImplicitStrictnessPosField Int + data BadFieldAnnotationReason where {-| A lazy data type field annotation (~) was used without enabling the extension LazyFieldAnnotations. ===================================== compiler/GHC/Tc/TyCl.hs ===================================== @@ -5022,6 +5022,16 @@ checkValidTyCon tc ; mapM_ (checkValidDataCon dflags ex_ok tc) data_cons ; mapM_ (checkPartialRecordField data_cons) (tyConFieldLabels tc) + ; warn_implicit_strictness <- woptM Opt_WarnImplicitFieldStrictness + ; when (warn_implicit_strictness + && not (isNewTyCon tc) + && not (isTypeDataTyCon tc)) $ + whenIsJust (NE.nonEmpty (mapMaybe conImplicitStrictnessFields data_cons)) $ + \offenders -> + do { lazy_anns <- xoptM LangExt.LazyFieldAnnotations + ; addDiagnosticTc $ + TcRnImplicitFieldStrictness lazy_anns offenders } + -- Check that fields with the same name share a type ; mapM_ check_fields groups }} where @@ -5072,6 +5082,26 @@ checkValidTyCon tc res2 = dataConOrigResTy con2 fty2 = dataConFieldType con2 lbl +-- | For a given data constructor, collect the fields to report for +-- @-Wimplicit-field-strictness@. +-- +-- Only fields whose type is known to be lifted are collected: unlifted +-- fields are unconditionally strict, and annotating one with @!@ or +-- @~@ would trigger @-Wredundant-strictness-flags@. +conImplicitStrictnessFields :: DataCon -> Maybe (Name, NonEmpty ImplicitStrictnessField) +conImplicitStrictnessFields con + = (,) (dataConName con) <$> NE.nonEmpty fields + where + fld_refs = case dataConFieldLabels con of + [] -> map ImplicitStrictnessPosField [1..] + lbls -> map (ImplicitStrictnessRecField . flLabel) lbls + fields = [ ref + | (ref, arg_ty, HsSrcBang _ _ NoSrcStrict) + <- zip3 fld_refs + (map scaledThing (dataConOrigArgTys con)) + (dataConSrcBangs con) + , typeLevity_maybe arg_ty == Just Lifted ] + checkPartialRecordField :: [DataCon] -> FieldLabel -> TcM () -- Checks the partial record field selector, and warns. -- See Note [Checking partial record field] ===================================== compiler/GHC/Types/Error/Codes.hs ===================================== @@ -542,6 +542,7 @@ type family GhcDiagnosticCode c = n | n -> c where GhcDiagnosticCode "TcRnNegativeNumTypeLiteral" = 93632 GhcDiagnosticCode "TcRnUnusedQuantifiedTypeVar" = 54180 GhcDiagnosticCode "TcRnMissingRoleAnnotation" = 65490 + GhcDiagnosticCode "TcRnImplicitFieldStrictness" = 47032 GhcDiagnosticCode "TcRnUntickedPromotedThing" = 49957 GhcDiagnosticCode "TcRnIllegalBuiltinSyntax" = 39716 ===================================== compiler/GHC/Types/Hint.hs ===================================== @@ -343,6 +343,14 @@ data GhcHint -} | SuggestAddStandaloneKindSignature Name + {-| Suggests to annotate each constructor field with explicit strictness + (@!@ or @~@). + + Triggered by: 'GHC.Tc.Errors.Types.TcRnImplicitFieldStrictness' + Test case(s): warnings/should_compile/T16836a + -} + | SuggestExplicitFieldStrictness + {-| Suggests the user to fill in the wildcard constraint to disambiguate which constraint that is. ===================================== compiler/GHC/Types/Hint/Ppr.hs ===================================== @@ -185,6 +185,9 @@ instance Outputable GhcHint where -> text "Use a standalone deriving declaration instead" SuggestAddStandaloneKindSignature name -> text "Add a standalone kind signature for" <+> quotes (ppr name) + SuggestExplicitFieldStrictness + -> text "Annotate each field with" <+> quotes (char '!') + <+> text "(strict) or" <+> quotes (char '~') <+> text "(lazy)" SuggestFillInWildcardConstraint -> text "Fill in the wildcard constraint yourself" SuggestAppropriateTHTick ns ===================================== docs/users_guide/exts/strict.rst ===================================== @@ -194,6 +194,9 @@ The ``~`` annotation must be written in prefix form:: See `GHC Proposal #229 <https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0229-w…>`__ for the precise rules. +See also :ghc-flag:`-Wimplicit-field-strictness`, which warns about +fields lacking an explicit annotation. + .. _strict-data: Strict-by-default data types ===================================== docs/users_guide/using-warnings.rst ===================================== @@ -2505,6 +2505,21 @@ of ``-W(no-)*``. In other words the type-class role cannot be accidentally left representational or phantom, which could affected the code correctness. +.. ghc-flag:: -Wimplicit-field-strictness + :shortdesc: warn when constructor fields lack explicit strictness annotations + :type: dynamic + :reverse: -Wno-implicit-field-strictness + :category: + + :since: 10.2.1 + :default: off + + .. index:: + single: strictness annotations, missing + + This warning reports data constructor fields that lack an explicit + strictness annotation (``!`` or ``~``). + .. ghc-flag:: -Wimplicit-rhs-quantification :shortdesc: warn when type variables on the RHS of a type synonym are implicitly quantified :type: dynamic ===================================== testsuite/tests/warnings/should_compile/T16836a.hs ===================================== @@ -0,0 +1,37 @@ +{-# OPTIONS_GHC -Wimplicit-field-strictness #-} +{-# LANGUAGE GADTs #-} +{-# LANGUAGE TypeFamilies #-} +{-# LANGUAGE TypeOperators #-} +module T16836a where + +-- plain multi-constructor data +-- warns for both constructors +data T a = MkT a Bool + | MkT2 !Int a + +-- record with a shared field group +-- warns for x, y and z; not for b +data R = MkR { x, y :: Int, z :: Char, b :: !Bool } + +-- infix constructor +-- warns for the first argument +data I = Int :+: !Bool + +-- GADT syntax +-- warns for the first argument +data G a where + MkG :: Int -> !Bool -> G a + +-- GADT record syntax +-- warns for gx +data GR a where + MkGR :: { gx :: Int, gy :: !Bool } -> GR a + +-- data family instance +-- warns +data family F a +data instance F Int = MkF Char + +-- fully annotated +-- doesn't warn +data S = MkS !Int !Bool ===================================== testsuite/tests/warnings/should_compile/T16836a.stderr ===================================== @@ -0,0 +1,55 @@ +T16836a.hs:9:1: warning: [GHC-47032] [-Wimplicit-field-strictness] + • These constructor fields lack an explicit strictness annotation: + • In ‘MkT’: fields 1 and 2 + • In ‘MkT2’: field 2 + • In the data type declaration for ‘T’ + Suggested fixes: + • Annotate each field with ‘!’ (strict) or ‘~’ (lazy) + • Use the ‘LazyFieldAnnotations’ extension (implied by ‘StrictData’) + to allow ‘~’ annotations + +T16836a.hs:14:1: warning: [GHC-47032] [-Wimplicit-field-strictness] + • These constructor fields lack an explicit strictness annotation: + • In ‘MkR’: fields ‘x’, ‘y’ and ‘z’ + • In the data type declaration for ‘R’ + Suggested fixes: + • Annotate each field with ‘!’ (strict) or ‘~’ (lazy) + • Use the ‘LazyFieldAnnotations’ extension (implied by ‘StrictData’) + to allow ‘~’ annotations + +T16836a.hs:18:1: warning: [GHC-47032] [-Wimplicit-field-strictness] + • These constructor fields lack an explicit strictness annotation: + • In ‘:+:’: field 1 + • In the data type declaration for ‘I’ + Suggested fixes: + • Annotate each field with ‘!’ (strict) or ‘~’ (lazy) + • Use the ‘LazyFieldAnnotations’ extension (implied by ‘StrictData’) + to allow ‘~’ annotations + +T16836a.hs:22:1: warning: [GHC-47032] [-Wimplicit-field-strictness] + • These constructor fields lack an explicit strictness annotation: + • In ‘MkG’: field 1 + • In the data type declaration for ‘G’ + Suggested fixes: + • Annotate each field with ‘!’ (strict) or ‘~’ (lazy) + • Use the ‘LazyFieldAnnotations’ extension (implied by ‘StrictData’) + to allow ‘~’ annotations + +T16836a.hs:27:1: warning: [GHC-47032] [-Wimplicit-field-strictness] + • These constructor fields lack an explicit strictness annotation: + • In ‘MkGR’: field ‘gx’ + • In the data type declaration for ‘GR’ + Suggested fixes: + • Annotate each field with ‘!’ (strict) or ‘~’ (lazy) + • Use the ‘LazyFieldAnnotations’ extension (implied by ‘StrictData’) + to allow ‘~’ annotations + +T16836a.hs:33:1: warning: [GHC-47032] [-Wimplicit-field-strictness] + • These constructor fields lack an explicit strictness annotation: + • In ‘MkF’: field 1 + • In the data family instance declaration for ‘F’ + Suggested fixes: + • Annotate each field with ‘!’ (strict) or ‘~’ (lazy) + • Use the ‘LazyFieldAnnotations’ extension (implied by ‘StrictData’) + to allow ‘~’ annotations + ===================================== testsuite/tests/warnings/should_compile/T16836b.hs ===================================== @@ -0,0 +1,25 @@ +{-# OPTIONS_GHC -Wimplicit-field-strictness #-} +{-# LANGUAGE GADTs #-} +{-# LANGUAGE TypeFamilies #-} +{-# LANGUAGE TypeData #-} +{-# LANGUAGE EmptyDataDecls #-} +{-# LANGUAGE LazyFieldAnnotations #-} +module T16836b where + +-- fully annotated declarations don't warn +data T a = MkT ~a !Bool +data R = MkR { x, y :: !Int, z :: ~Char } +data G a where + MkG :: !Int -> ~Bool -> G a +data family F a +data instance F Int = MkF !Char + +-- newtypes can't have annotations; exempt +newtype N = MkN Int + +-- 'type data' can't have annotations; exempt +type data TD = MkTD Bool + +-- no fields, nothing to annotate +data E +data Nullary = A | B ===================================== testsuite/tests/warnings/should_compile/T16836c.hs ===================================== @@ -0,0 +1,6 @@ +{-# OPTIONS_GHC -Wimplicit-field-strictness #-} +{-# LANGUAGE StrictData #-} +module T16836c where + +-- unannotated fields warn under StrictData too +data T a = MkT a !Bool ~Char ===================================== testsuite/tests/warnings/should_compile/T16836c.stderr ===================================== @@ -0,0 +1,6 @@ +T16836c.hs:6:1: warning: [GHC-47032] [-Wimplicit-field-strictness] + • These constructor fields lack an explicit strictness annotation: + • In ‘MkT’: field 1 + • In the data type declaration for ‘T’ + Suggested fix: Annotate each field with ‘!’ (strict) or ‘~’ (lazy) + ===================================== testsuite/tests/warnings/should_compile/T16836d.hs ===================================== @@ -0,0 +1,20 @@ +{-# OPTIONS_GHC -Wimplicit-field-strictness #-} +{-# LANGUAGE MagicHash #-} +{-# LANGUAGE UnboxedTuples #-} +{-# LANGUAGE UnliftedDatatypes #-} +module T16836d where + +import GHC.Exts + +-- unlifted fields can't be usefully annotated; exempt +data P = MkP Int# (# Int, Int #) + +type UD :: UnliftedType +data UD = MkUD + +-- a field of an unlifted data type is exempt too +data Q = MkQ UD + +-- mixed constructor +-- warns only for the lifted field 2 +data M = MkM Int# Int ===================================== testsuite/tests/warnings/should_compile/T16836d.stderr ===================================== @@ -0,0 +1,9 @@ +T16836d.hs:20:1: warning: [GHC-47032] [-Wimplicit-field-strictness] + • These constructor fields lack an explicit strictness annotation: + • In ‘MkM’: field 2 + • In the data type declaration for ‘M’ + Suggested fixes: + • Annotate each field with ‘!’ (strict) or ‘~’ (lazy) + • Use the ‘LazyFieldAnnotations’ extension (implied by ‘StrictData’) + to allow ‘~’ annotations + ===================================== testsuite/tests/warnings/should_compile/all.T ===================================== @@ -91,3 +91,7 @@ test('T25901_imp_unused_3', [extra_files(['T25901_helper_3.hs'])], multimod_comp test('T25901_imp_unused_4', normal, compile, ['-Wunused-imports']) test('T25901_imp_dodgy_1', [extra_files(['T25901_helper_1.hs'])], multimod_compile, ['T25901_imp_dodgy_1', '-v0 -Wdodgy-imports']) test('T25901_imp_dodgy_2', [extra_files(['T25901_helper_2.hs'])], multimod_compile, ['T25901_imp_dodgy_2', '-v0 -Wdodgy-imports']) +test('T16836a', normal, compile, ['']) +test('T16836b', normal, compile, ['']) +test('T16836c', normal, compile, ['']) +test('T16836d', normal, compile, ['']) View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/5bade2e3287e8f18a7449710fc61660… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/5bade2e3287e8f18a7449710fc61660… You're receiving this email because of your account on gitlab.haskell.org. 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[Git][ghc/ghc][wip/az/epa-tidy-locatedxxx-20] EPA: Uses Parsers.parseModule for exactprint tests
by Alan Zimmerman (＠alanz) 22 Aug '26

22 Aug '26

Alan Zimmerman pushed to branch wip/az/epa-tidy-locatedxxx-20 at Glasgow Haskell Compiler / GHC Commits: 55776411 by Alan Zimmerman at 2026-08-22T13:37:26+01:00 EPA: Uses Parsers.parseModule for exactprint tests Parsers.parseModule is the advertised way to parse for use for exact printing in the ghc-exactprint library. This commit updates the GHC exact print testing to use it. This requires moving the comment balancing that was occurring only in the test path into the advertising parser path, so it moves from Transforms.hs to Utils.hs. Also update the comment adding to honour trailing annotations - - - - - 5 changed files: - utils/check-exact/ExactPrint.hs - utils/check-exact/Main.hs - utils/check-exact/Parsers.hs - utils/check-exact/Transform.hs - utils/check-exact/Utils.hs Changes: ===================================== utils/check-exact/ExactPrint.hs ===================================== @@ -1465,7 +1465,7 @@ instance ExactPrint (HsModule GhcPs) where Just exps -> do let (op,cp,tcs) = am_exports $ anns an0 op' <- markEpToken op - exps' <- mapM markAnnotated exps + exps' <- mapM markAnnotated (filter notIEDoc exps) tcs' <- mapM markEpToken tcs cp' <- markEpToken cp return (Just exps', an0 { anns = (anns an0) { am_exports = (op',cp',tcs')}}) ===================================== utils/check-exact/Main.hs ===================================== @@ -183,7 +183,8 @@ _tt = testOneFile changers "/home/alanz/mysrc/git.haskell.org/ghc/_build/stage1/ -- "../../testsuite/tests/printer/Test17519.hs" Nothing -- "../../testsuite/tests/printer/InTreeAnnotations1.hs" Nothing -- "../../testsuite/tests/printer/Test19798.hs" Nothing - "../../testsuite/tests/printer/Test10309.hs" Nothing + -- "../../testsuite/tests/printer/Test10309.hs" Nothing + "../../testsuite/tests/printer/Haddock1.hs" Nothing -- "../../testsuite/tests/qualifieddo/should_compile/qdocompile001.hs" Nothing -- "../../testsuite/tests/typecheck/should_fail/StrictBinds.hs" Nothing @@ -304,7 +305,7 @@ writeBinFile fpath x = withBinaryFile fpath WriteMode (\h -> hSetEncoding h utf8 testOneFile :: [(String, Changer)] -> FilePath -> String -> Maybe Changer -> IO () testOneFile _ libdir fileName mchanger = do - (p,_toks) <- parseOneFile libdir fileName + p <- parseOneFile libdir fileName let origAst = ppAst p pped = exactPrint p @@ -333,7 +334,7 @@ testOneFile _ libdir fileName mchanger = do changedSource <- readFile newFile return (expectedSource == changedSource, expectedSource, changedSource) - (p',_) <- parseOneFile libdir newFile + p' <- parseOneFile libdir newFile let newAstStr :: String newAstStr = ppAst p' writeBinFile newAstFile newAstStr @@ -364,15 +365,12 @@ testOneFile _ libdir fileName mchanger = do ppAst :: Data a => a -> String ppAst ast = showSDocUnsafe $ showAstData BlankSrcSpanFile NoBlankEpAnnotations ast - -parseOneFile :: FilePath -> FilePath -> IO (ParsedSource, [Located Token]) +parseOneFile :: FilePath -> FilePath -> IO ParsedSource parseOneFile libdir fileName = do - res <- parseModuleEpAnnsWithCpp libdir defaultCppOptions fileName + res <- Parsers.parseModule libdir fileName case res of Left m -> error (internalDebugShowMessages m) - Right (injectedComments, _dflags, pmod) -> do - let !pmodWithComments = insertCppComments pmod injectedComments - return (pmodWithComments, []) + Right pmod -> do return pmod -- --------------------------------------------------------------------- @@ -519,8 +517,7 @@ changeLocalDecls libdir (L l p) = do replaceLocalBinds :: LMatch GhcPs (LHsExpr GhcPs) -> Transform (LMatch GhcPs (LHsExpr GhcPs)) replaceLocalBinds (L lm (Match an mln pats (GRHSs _ rhs (HsValBinds (van,w) (ValBinds _ bs))))) = do - let (oldDecls) = map unWrapValBind bs - -- let decls = s:d:oldDecls + let oldDecls = map unWrapValBind bs let oldDecls' = captureLineSpacing oldDecls let (VbSig o:oldBinds) = map wrapValBind oldDecls' o' = setEntryDP o (DifferentLine 2 0) ===================================== utils/check-exact/Parsers.hs ===================================== @@ -46,6 +46,7 @@ module Parsers ( ) where import Preprocess +import Utils import Data.Functor (void) @@ -270,7 +271,10 @@ postParseTransform -> Either a (GHC.ParsedSource) postParseTransform parseRes = fmap mkAnns parseRes where - mkAnns (_cs, _, m) = fixModuleComments m + mkAnns (cs, _, m) = fixModuleComments (insertCppComments (noIEDoc m) cs) + noIEDoc (GHC.L l m) = case GHC.hsmodExports m of + Nothing -> GHC.L l m + Just exps -> GHC.L l m { GHC.hsmodExports = Just $ filter notIEDoc exps } fixModuleComments :: GHC.ParsedSource -> GHC.ParsedSource fixModuleComments p = fixModuleHeaderComments $ fixModuleTrailingComments p ===================================== utils/check-exact/Transform.hs ===================================== @@ -93,7 +93,6 @@ import qualified Control.Monad.Fail as Fail import GHC hiding (parseModule, parsedSource) import GHC.Parser.PostProcess ( wrapValBind ) import GHC.Data.FastString -import GHC.Types.SrcLoc import Data.Data import Data.List (unsnoc) @@ -402,6 +401,14 @@ balanceCommentsList' (a:b:ls) = (a':r) (a',b') = balanceComments a b r = balanceCommentsList' (b':ls) +balanceCommentsListA :: [LocatedA a ] -> [LocatedA a] +balanceCommentsListA [] = [] +balanceCommentsListA [x] = [x] +balanceCommentsListA (a:b:ls) = (a':r) + where + (a',b') = balanceCommentsA a b + r = balanceCommentsListA (b':ls) + -- |The GHC parser puts all comments appearing between the end of one AST -- item and the beginning of the next as 'annPriorComments' for the second one. -- This function takes two adjacent AST items and moves any 'annPriorComments' @@ -507,15 +514,6 @@ pushTrailingComments w cs lb@(HsValBinds (an,wt) _) = (True, HsValBinds (an',wt) (HsValBinds _ vb') -> vb' _ -> ValBinds noExtField [] - -balanceCommentsListA :: [LocatedA a] -> [LocatedA a] -balanceCommentsListA [] = [] -balanceCommentsListA [x] = [x] -balanceCommentsListA (a:b:ls) = (a':r) - where - (a',b') = balanceCommentsA a b - r = balanceCommentsListA (b':ls) - -- |Prior to moving an AST element, make sure any trailing comments belonging to -- it are attached to it, and not the following element. Of necessity this is a -- heuristic process, to be tuned later. Possibly a variant should be provided @@ -591,59 +589,6 @@ priorCommentsDeltas r cs = go r (sortEpaComments cs) -- --------------------------------------------------------------------- --- | Split comments into ones occurring before the end of the reference --- span, and those after it. -splitComments :: RealSrcSpan -> EpAnnComments -> ([LEpaComment], [LEpaComment], [LEpaComment]) -splitComments p cs = (before, middle, after) - where - cmpe (L (EpaSpan (RealSrcSpan l _)) _) = ss2pos l > ss2posEnd p - cmpe (L _ _) = True - - cmpb (L (EpaSpan (RealSrcSpan l _)) _) = ss2pos l > ss2pos p - cmpb (L _ _) = True - - (beforeEnd, after) = break cmpe ((priorComments cs) ++ (getFollowingComments cs)) - (before, middle) = break cmpb beforeEnd - - --- | Split comments into ones occurring before the end of the reference --- span, and those after it. -splitCommentsEnd :: RealSrcSpan -> EpAnnComments -> EpAnnComments -splitCommentsEnd p (EpaComments cs) = cs' - where - cmp (L (EpaSpan (RealSrcSpan l _)) _) = ss2pos l > ss2posEnd p - cmp (L _ _) = True - (before, after) = break cmp cs - cs' = case after of - [] -> EpaComments cs - _ -> epaCommentsBalanced before after -splitCommentsEnd p (EpaCommentsBalanced cs ts) = epaCommentsBalanced cs' ts' - where - cmp (L (EpaSpan (RealSrcSpan l _)) _) = ss2pos l > ss2posEnd p - cmp (L _ _) = True - (before, after) = break cmp cs - cs' = before - ts' = after <> ts - --- | Split comments into ones occurring before the start of the reference --- span, and those after it. -splitCommentsStart :: RealSrcSpan -> EpAnnComments -> EpAnnComments -splitCommentsStart p (EpaComments cs) = cs' - where - cmp (L (EpaSpan (RealSrcSpan l _)) _) = ss2pos l > ss2posEnd p - cmp (L _ _) = True - (before, after) = break cmp cs - cs' = case after of - [] -> EpaComments cs - _ -> epaCommentsBalanced before after -splitCommentsStart p (EpaCommentsBalanced cs ts) = epaCommentsBalanced cs' ts' - where - cmp (L (EpaSpan (RealSrcSpan l _)) _) = ss2pos l > ss2posEnd p - cmp (L _ _) = True - (before, after) = break cmp cs - cs' = before - ts' = after <> ts - moveLeadingComments :: (Data t, Data u, NoAnn t, NoAnn u) => LocatedAn t a -> EpAnn u -> (LocatedAn t a, EpAnn u) moveLeadingComments (L la a) lb = (L la' a, lb') @@ -680,19 +625,6 @@ addCommentOrigDeltasAnn (EpAnn e a cs) = EpAnn e a (addCommentOrigDeltas cs) anchorFromLocatedA :: LocatedA a -> RealSrcSpan anchorFromLocatedA (L (EpAnn anc _ _) _) = epaLocationRealSrcSpan anc --- | Get the full span of interest for comments from a LocatedA. --- This extends up to the last TrailingAnn -fullSpanFromLocatedA :: LocatedA a -> RealSrcSpan -fullSpanFromLocatedA (L (EpAnn anc tas _) _) = rr - where - r = epaLocationRealSrcSpan anc - trailing_loc ta = case ta_location ta of - EpaSpan (RealSrcSpan s _) -> [s] - _ -> [] - rr = case reverse (concatMap trailing_loc tas) of - [] -> r - (s:_) -> combineRealSrcSpans r s - -- --------------------------------------------------------------------- balanceSameLineComments :: LMatch GhcPs (LHsExpr GhcPs) -> (LMatch GhcPs (LHsExpr GhcPs)) ===================================== utils/check-exact/Utils.hs ===================================== @@ -228,7 +228,7 @@ insertCppComments (L l p) cs0 = insertRemainingCppComments (L l p2) remaining (p2, remaining) = insertTopLevelCppComments p1 toplevel addCommentsListItem :: EpAnn [TrailingAnn] -> State [LEpaComment] (EpAnn [TrailingAnn]) - addCommentsListItem = addComments + addCommentsListItem = addCommentsA addCommentsList :: EpAnn AnnList -> State [LEpaComment] (EpAnn AnnList) addCommentsList = addComments @@ -249,6 +249,20 @@ insertCppComments (L l p) cs0 = insertRemainingCppComments (L l p2) remaining _ -> return $ EpAnn anc an ocs + addCommentsA :: EpAnn [TrailingAnn] -> State [LEpaComment] (EpAnn [TrailingAnn]) + addCommentsA ann@(EpAnn anc an ocs) = do + case anc of + EpaSpan (RealSrcSpan s _) -> do + unAllocated <- get + let + (rest, these) = GHC.Parser.Lexer.allocateComments (fullSpanFromEpAnnA ann) unAllocated + balanced = splitCommentsEnd s (EpaComments these) + cs' = sortEpAnnComments (ocs <> balanced) + put rest + return $ EpAnn anc an cs' + + _ -> return $ EpAnn anc an ocs + workInComments :: EpAnnComments -> [LEpaComment] -> EpAnnComments workInComments ocs [] = ocs workInComments ocs new = cs' @@ -264,9 +278,14 @@ workInComments ocs new = cs' = break (\(L ll _) -> (ss2pos $ epaLocationRealSrcSpan ll) > (ss2pos $ epaLocationRealSrcSpan ac) ) new +sortEpAnnComments :: EpAnnComments -> EpAnnComments +sortEpAnnComments (EpaComments cs) = EpaComments (sortEpaComments cs) +sortEpAnnComments (EpaCommentsBalanced pc fc) + = EpaCommentsBalanced (sortEpaComments pc) (sortEpaComments fc) + insertTopLevelCppComments :: HsModule GhcPs -> [LEpaComment] -> (HsModule GhcPs, [LEpaComment]) insertTopLevelCppComments (HsModule (XModulePs an lo mdeprec mbDoc) mmn mexports imports decls) cs - = (HsModule (XModulePs an4 lo mdeprec mbDoc) mmn mexports' imports' decls', cs3) + = (HsModule (XModulePs an4 lo mdeprec mbDoc) mmn mexports imports' decls', cs3) -- `debug` ("insertTopLevelCppComments: (cs2,cs3,hc0,hc1,hc_cs)" ++ showAst (cs2,cs3,hc0,hc1,hc_cs)) -- `debug` ("insertTopLevelCppComments: (cs2,cs3,hc0i,hc0,hc1,hc_cs)" ++ showAst (cs2,cs3,hc0i,hc0,hc1,hc_cs)) where @@ -297,24 +316,7 @@ insertTopLevelCppComments (HsModule (XModulePs an lo mdeprec mbDoc) mmn mexports cs' = workInComments (comments an1) stay _ -> (an1,cs0a) - (mexports', an3, cs1) = - case mexports of - Nothing -> (Nothing, an2, cs0b) - Just exports -> (Just exports', an3', cse) - where - (csh', cs0b') = case am_exports $ anns an2 of - (tokOP, _tokCP, _tokCommas) -> - case tokOP of - (EpTok (EpaSpan (RealSrcSpan s _))) -> (h, n) - where - (h,n) = break (\(L ll _) -> (ss2pos $ epaLocationRealSrcSpan ll) > (ss2pos s) ) - cs0b - - _ -> ([], cs0b) - hc1' = workInComments (comments an2) csh' - an3' = an2 { comments = hc1' } - (exports', cse) = allocPreceding exports cs0b' - (imports0, cs2) = allocPreceding imports cs1 + (imports0, cs2) = allocPreceding imports cs0b (imports', hc0i) = balanceFirstLocatedAComments imports0 (decls0, cs3) = allocPreceding decls cs2 @@ -323,9 +325,9 @@ insertTopLevelCppComments (HsModule (XModulePs an lo mdeprec mbDoc) mmn mexports -- Either hc0i or hc0d should have comments. Combine them hc0 = hc0i ++ hc0d - (hc1,hc_cs) = splitOnWhere After (am_where $ anns an3) hc0 - hc2 = workInComments (comments an3) hc1 - an4 = an3 { anns = (anns an3) {am_cs = hc_cs}, comments = hc2 } + (hc1,hc_cs) = splitOnWhere After (am_where $ anns an2) hc0 + hc2 = workInComments (comments an2) hc1 + an4 = an2 { anns = (anns an2) {am_cs = hc_cs}, comments = hc2 } allocPreceding :: [LocatedA a] -> [LEpaComment] -> ([LocatedA a], [LEpaComment]) allocPreceding [] cs' = ([], cs') @@ -346,7 +348,6 @@ annListBracketsLocs (ListSquare o c) = (getEpTokenLoc o, getEpTokenLoc c) annListBracketsLocs (ListBanana o c) = (getEpUniTokenLoc o, getEpUniTokenLoc c) annListBracketsLocs ListNone = (noAnn, noAnn) - data SplitWhere = Before | After splitOnWhere :: SplitWhere -> EpToken "where" -> [LEpaComment] -> ([LEpaComment], [LEpaComment]) @@ -430,6 +431,79 @@ insertRemainingCppComments (L l p) cs = L l p' -- --------------------------------------------------------------------- +-- | Get the full span of interest for comments from a LocatedA. +-- This extends up to the last TrailingAnn +fullSpanFromLocatedA :: LocatedA a -> RealSrcSpan +fullSpanFromLocatedA (L ann _) = fullSpanFromEpAnnA ann + +-- | Get the full span of interest for comments from a LocatedA. +-- This extends up to the last TrailingAnn +fullSpanFromEpAnnA :: EpAnn [TrailingAnn] -> RealSrcSpan +fullSpanFromEpAnnA (EpAnn anc tas _) = rr + where + r = epaLocationRealSrcSpan anc + trailing_loc ta = case ta_location ta of + EpaSpan (RealSrcSpan s _) -> [s] + _ -> [] + rr = case reverse (concatMap trailing_loc tas) of + [] -> r + (s:_) -> combineRealSrcSpans r s + +-- | Split comments into ones occurring before the end of the reference +-- span, and those after it. +splitComments :: RealSrcSpan -> EpAnnComments -> ([LEpaComment], [LEpaComment], [LEpaComment]) +splitComments p cs = (before, middle, after) + where + cmpe (L (EpaSpan (RealSrcSpan l _)) _) = ss2pos l > ss2posEnd p + cmpe (L _ _) = True + + cmpb (L (EpaSpan (RealSrcSpan l _)) _) = ss2pos l > ss2pos p + cmpb (L _ _) = True + + (beforeEnd, after) = break cmpe ((priorComments cs) ++ (getFollowingComments cs)) + (before, middle) = break cmpb beforeEnd + + +-- | Split comments into ones occurring before the end of the reference +-- span, and those after it. +splitCommentsEnd :: RealSrcSpan -> EpAnnComments -> EpAnnComments +splitCommentsEnd p (EpaComments cs) = cs' + where + cmp (L (EpaSpan (RealSrcSpan l _)) _) = ss2pos l > ss2posEnd p + cmp (L _ _) = True + (before, after) = break cmp cs + cs' = case after of + [] -> EpaComments cs + _ -> epaCommentsBalanced before after +splitCommentsEnd p (EpaCommentsBalanced cs ts) = epaCommentsBalanced cs' ts' + where + cmp (L (EpaSpan (RealSrcSpan l _)) _) = ss2pos l > ss2posEnd p + cmp (L _ _) = True + (before, after) = break cmp cs + cs' = before + ts' = after <> ts + +-- | Split comments into ones occurring before the start of the reference +-- span, and those after it. +splitCommentsStart :: RealSrcSpan -> EpAnnComments -> EpAnnComments +splitCommentsStart p (EpaComments cs) = cs' + where + cmp (L (EpaSpan (RealSrcSpan l _)) _) = ss2pos l > ss2posEnd p + cmp (L _ _) = True + (before, after) = break cmp cs + cs' = case after of + [] -> EpaComments cs + _ -> epaCommentsBalanced before after +splitCommentsStart p (EpaCommentsBalanced cs ts) = epaCommentsBalanced cs' ts' + where + cmp (L (EpaSpan (RealSrcSpan l _)) _) = ss2pos l > ss2posEnd p + cmp (L _ _) = True + (before, after) = break cmp cs + cs' = before + ts' = after <> ts + +-- --------------------------------------------------------------------- + ghcCommentText :: LEpaComment -> String ghcCommentText (L _ (GHC.EpaComment (EpaDocComment s) _)) = exactPrintHsDocString s ghcCommentText (L _ (GHC.EpaComment (EpaDocOptions s) _)) = s View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/55776411ed86399d4553a27ca89ec0b… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/55776411ed86399d4553a27ca89ec0b… You're receiving this email because of your account on gitlab.haskell.org. 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[Git][ghc/ghc] Pushed new branch wip/az/epa-tidy-locatedxxx-20
by Alan Zimmerman (＠alanz) 22 Aug '26

22 Aug '26

Alan Zimmerman pushed new branch wip/az/epa-tidy-locatedxxx-20 at Glasgow Haskell Compiler / GHC -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/tree/wip/az/epa-tidy-locatedxxx-20 You're receiving this email because of your account on gitlab.haskell.org. Manage all notifications: https://gitlab.haskell.org/-/profile/notifications | Help: https://gitlab.haskell.org/help

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[Git][ghc/ghc] Pushed new branch wip/T27731
by Simon Peyton Jones (＠simonpj) 22 Aug '26

22 Aug '26

Simon Peyton Jones pushed new branch wip/T27731 at Glasgow Haskell Compiler / GHC -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/tree/wip/T27731 You're receiving this email because of your account on gitlab.haskell.org. Manage all notifications: https://gitlab.haskell.org/-/profile/notifications | Help: https://gitlab.haskell.org/help

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[Git][ghc/ghc] Pushed new branch wip/T27731
by Simon Peyton Jones (＠simonpj) 22 Aug '26

22 Aug '26

Simon Peyton Jones pushed new branch wip/T27731 at Glasgow Haskell Compiler / GHC -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/tree/wip/T27731 You're receiving this email because of your account on gitlab.haskell.org. Manage all notifications: https://gitlab.haskell.org/-/profile/notifications | Help: https://gitlab.haskell.org/help

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[Git][ghc/ghc] Pushed new branch wip/sjakobi/T27628-rebox-warning
by Simon Jakobi (＠sjakobi) 22 Aug '26

22 Aug '26

Simon Jakobi pushed new branch wip/sjakobi/T27628-rebox-warning at Glasgow Haskell Compiler / GHC -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/tree/wip/sjakobi/T27628-rebox-warning You're receiving this email because of your account on gitlab.haskell.org. Manage all notifications: https://gitlab.haskell.org/-/profile/notifications | Help: https://gitlab.haskell.org/help

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[Git][ghc/ghc][wip/sjakobi/T27732-type-data-field-annotations] Reject `~` and UNPACK annotations on type data fields
by Simon Jakobi (＠sjakobi) 22 Aug '26

22 Aug '26

Simon Jakobi pushed to branch wip/sjakobi/T27732-type-data-field-annotations at Glasgow Haskell Compiler / GHC Commits: 76238d25 by Simon Jakobi at 2026-08-22T03:15:38+02:00 Reject `~` and UNPACK annotations on type data fields Widen restriction (R3) of Note [Type data declarations] to any strictness or unpackedness annotation — none of them make sense at the type level — and generalize the check and error message accordingly. Fixes #27732 Assisted-by: Claude Fable 5 - - - - - 15 changed files: - + changelog.d/27732 - compiler/GHC/Rename/Module.hs - compiler/GHC/Tc/Errors/Types.hs - docs/users_guide/exts/type_data.rst - + testsuite/tests/type-data/should_fail/T27732a.hs - + testsuite/tests/type-data/should_fail/T27732a.stderr - + testsuite/tests/type-data/should_fail/T27732b.hs - + testsuite/tests/type-data/should_fail/T27732b.stderr - + testsuite/tests/type-data/should_fail/T27732c.hs - + testsuite/tests/type-data/should_fail/T27732c.stderr - + testsuite/tests/type-data/should_fail/T27732d.hs - + testsuite/tests/type-data/should_fail/T27732d.stderr - testsuite/tests/type-data/should_fail/TDStrictnessGADT.stderr - testsuite/tests/type-data/should_fail/TDStrictnessH98.stderr - testsuite/tests/type-data/should_fail/all.T Changes: ===================================== changelog.d/27732 ===================================== @@ -0,0 +1,8 @@ +section: language +synopsis: Reject `~` and UNPACK annotations on type data fields +description: + ``type data`` declarations (:extension:`TypeData`) now reject any + strictness or unpackedness annotation on constructor fields. + Previously only ``!`` was rejected. +mrs: !16563 +issues: #27732 ===================================== compiler/GHC/Rename/Module.hs ===================================== @@ -71,7 +71,6 @@ import GHC.Data.Graph.Directed ( SCC, flattenSCC, Node(..) , stronglyConnCompFromEdgedVerticesUniq ) import GHC.Data.OrdList import qualified GHC.LanguageExtensions as LangExt -import GHC.Core.DataCon ( isSrcStrict ) import Control.Monad import Data.Bifunctor ( first ) @@ -2116,8 +2115,8 @@ rnDataDefn doc (HsDataDefn { dd_cType = cType, dd_ctxt = context, dd_cons = cond = do { ; when (has_labelled_fields condecl) $ failWith $ TcRnTypeDataForbids TypeDataForbidsLabelledFields - ; when (has_strictness_flags condecl) $ - failWith $ TcRnTypeDataForbids TypeDataForbidsStrictnessAnnotations + ; when (has_field_annotations condecl) $ + failWith $ TcRnTypeDataForbids TypeDataForbidsFieldAnnotations } has_labelled_fields (ConDeclGADT { con_g_args = RecConGADT _ _ }) = True @@ -2125,13 +2124,16 @@ rnDataDefn doc (HsDataDefn { dd_cType = cType, dd_ctxt = context, dd_cons = cond = not (null (unLoc flds)) has_labelled_fields _ = False - has_strictness_flags condecl - = any isSrcStrict (con_arg_bangs condecl) + has_field_annotations condecl + = any is_annotated (con_arg_fields condecl) + where + is_annotated (CDF { cdf_bang = bang, cdf_unpack = unpack }) + = bang /= NoSrcStrict || unpack /= NoSrcUnpack - con_arg_bangs (ConDeclGADT { con_g_args = PrefixConGADT _ args }) = map cdf_bang args - con_arg_bangs (ConDeclH98 { con_args = PrefixCon _ args }) = map cdf_bang args - con_arg_bangs (ConDeclH98 { con_args = InfixCon _ arg1 arg2 }) = [cdf_bang arg1, cdf_bang arg2] - con_arg_bangs _ = [] + con_arg_fields (ConDeclGADT { con_g_args = PrefixConGADT _ args }) = args + con_arg_fields (ConDeclH98 { con_args = PrefixCon _ args }) = args + con_arg_fields (ConDeclH98 { con_args = InfixCon _ arg1 arg2 }) = [arg1, arg2] + con_arg_fields _ = [] {- Note [Type data declarations] @@ -2166,8 +2168,9 @@ preceded by `type`, with the following restrictions: (R2) There are no labelled fields. Perhaps these could be supported using type families, but they are omitted for now. -(R3) There are no strictness flags, because they don't make sense at - the type level. +(R3) There are no strictness or unpackedness annotations (!, ~, + {-# UNPACK #-}, {-# NOUNPACK #-}), because they don't make sense + at the type level. (R4) The types of the constructors contain no constraints. ===================================== compiler/GHC/Tc/Errors/Types.hs ===================================== @@ -2865,6 +2865,10 @@ data TcRnMessage where type-data/should_fail/TDRecordsH98 type-data/should_fail/TDStrictnessGADT type-data/should_fail/TDStrictnessH98 + type-data/should_fail/T27732a + type-data/should_fail/T27732b + type-data/should_fail/T27732c + type-data/should_fail/T27732d -} TcRnTypeDataForbids :: !TypeDataForbids -> TcRnMessage @@ -4523,15 +4527,15 @@ data ZonkerMessage where data TypeDataForbids = TypeDataForbidsDatatypeContexts | TypeDataForbidsLabelledFields - | TypeDataForbidsStrictnessAnnotations + | TypeDataForbidsFieldAnnotations | TypeDataForbidsDerivingClauses deriving Generic instance Outputable TypeDataForbids where - ppr TypeDataForbidsDatatypeContexts = text "Data type contexts" - ppr TypeDataForbidsLabelledFields = text "Labelled fields" - ppr TypeDataForbidsStrictnessAnnotations = text "Strictness flags" - ppr TypeDataForbidsDerivingClauses = text "Deriving clauses" + ppr TypeDataForbidsDatatypeContexts = text "Data type contexts" + ppr TypeDataForbidsLabelledFields = text "Labelled fields" + ppr TypeDataForbidsFieldAnnotations = text "Strictness or unpackedness annotations" + ppr TypeDataForbidsDerivingClauses = text "Deriving clauses" -- | Specifies which back ends can handle a requested foreign import or export type ExpectedBackends = [Backend] ===================================== docs/users_guide/exts/type_data.rst ===================================== @@ -33,7 +33,7 @@ either an ordinary algebraic data type or a GADT, prefixed with the keyword ``type``, except that it may not contain a datatype context (even with :extension:`DatatypeContexts`), labelled fields, -strictness flags, or +:ref:`strictness <strict-haskell>` or :ref:`unpackedness <unpack-pragma>` annotations, or a ``deriving`` clause. The only constraints permitted in the types of constructors are ===================================== testsuite/tests/type-data/should_fail/T27732a.hs ===================================== @@ -0,0 +1,4 @@ +{-# LANGUAGE TypeData, LazyFieldAnnotations #-} +module T27732a where + +type data T a = Cons ~a ===================================== testsuite/tests/type-data/should_fail/T27732a.stderr ===================================== @@ -0,0 +1,3 @@ +T27732a.hs:4:17: error: [GHC-67297] + Strictness or unpackedness annotations are not allowed in type data declarations. + ===================================== testsuite/tests/type-data/should_fail/T27732b.hs ===================================== @@ -0,0 +1,5 @@ +{-# LANGUAGE TypeData, LazyFieldAnnotations #-} +module T27732b where + +type data T a where + Cons :: ~a -> T a ===================================== testsuite/tests/type-data/should_fail/T27732b.stderr ===================================== @@ -0,0 +1,3 @@ +T27732b.hs:5:6: error: [GHC-67297] + Strictness or unpackedness annotations are not allowed in type data declarations. + ===================================== testsuite/tests/type-data/should_fail/T27732c.hs ===================================== @@ -0,0 +1,4 @@ +{-# LANGUAGE TypeData #-} +module T27732c where + +type data T a = Cons {-# UNPACK #-} a ===================================== testsuite/tests/type-data/should_fail/T27732c.stderr ===================================== @@ -0,0 +1,3 @@ +T27732c.hs:4:17: error: [GHC-67297] + Strictness or unpackedness annotations are not allowed in type data declarations. + ===================================== testsuite/tests/type-data/should_fail/T27732d.hs ===================================== @@ -0,0 +1,4 @@ +{-# LANGUAGE TypeData #-} +module T27732d where + +type data T a = Cons {-# NOUNPACK #-} a ===================================== testsuite/tests/type-data/should_fail/T27732d.stderr ===================================== @@ -0,0 +1,3 @@ +T27732d.hs:4:17: error: [GHC-67297] + Strictness or unpackedness annotations are not allowed in type data declarations. + ===================================== testsuite/tests/type-data/should_fail/TDStrictnessGADT.stderr ===================================== @@ -1,3 +1,3 @@ +TDStrictnessGADT.hs:5:6: error: [GHC-67297] + Strictness or unpackedness annotations are not allowed in type data declarations. -TDStrictnessGADT.hs:5:6: [GHC-67297] - Strictness flags are not allowed in type data declarations. ===================================== testsuite/tests/type-data/should_fail/TDStrictnessH98.stderr ===================================== @@ -1,3 +1,3 @@ +TDStrictnessH98.hs:4:17: error: [GHC-67297] + Strictness or unpackedness annotations are not allowed in type data declarations. -TDStrictnessH98.hs:4:17: [GHC-67297] - Strictness flags are not allowed in type data declarations. ===================================== testsuite/tests/type-data/should_fail/all.T ===================================== @@ -13,3 +13,7 @@ test('TDStrictnessGADT', normal, compile_fail, ['']) test('TDStrictnessH98', normal, compile_fail, ['']) test('TDTagToEnum', normal, compile_fail, ['']) test('T22332b', normal, compile_fail, ['']) +test('T27732a', normal, compile_fail, ['']) +test('T27732b', normal, compile_fail, ['']) +test('T27732c', normal, compile_fail, ['']) +test('T27732d', normal, compile_fail, ['']) View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/76238d25514b322b45939e8ec9bce78… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/76238d25514b322b45939e8ec9bce78… You're receiving this email because of your account on gitlab.haskell.org. 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