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[Git][ghc/ghc][wip/fendor/has-field-hie] 3 commits: Allow any `Id` to be used for HIE evidence
by Hannes Siebenhandl (＠fendor) 16 Sep '26

16 Sep '26

Hannes Siebenhandl pushed to branch wip/fendor/has-field-hie at Glasgow Haskell Compiler / GHC Commits: f1e31835 by fendor at 2026-09-16T15:31:55+02:00 Allow any `Id` to be used for HIE evidence HIE evidence is used to show how a constraint has been solved and allows users to go directly to the definition or introduction of a particular evidence variable. So far, we only looked at evidence introduced by type class variables, but some evidence terms refer to other variables as well, such as record selectors. Such evidence terms add additional details and source locations. For generated evidence, such as `HasField` evidence to support `-XRecordDotSyntax`, the type class evidence is lacking and doesn't give us any usable source span pointing to the actual record selector. See this example evidence: $dHasField_aLw = GHC.Internal.Records.C:HasField @GHC.Internal.Types.Symbol @GHC.Internal.Types.LiftedRep @GHC.Internal.Types.LiftedRep @"foo" @Foo @Int (foo `cast` (<Foo -> Int>_R :: (Foo -> Int) ~R# (Foo -> Int))) The free variables of this term are `{C:HasField, foo}`. `foo` is the record selector from the type `Foo` and is crucial to guide users how this evidence is constructed, as the evidence `HasField` is not helpful. During HIE generation, we now take any `Id` into account to provide additional source spans to point to user to the definition site of the record selector. As a direct consequence, this allows HLS to implement a limited form of `Goto Definition` for expressions of the form `x.foo`, where `x :: Foo`. Capturing more `Id`s for evidence may have some side effects that are somewhat tricky to predict, since the tests are quite lacking. - - - - - 5c3ce3fe by fendor at 2026-09-16T15:32:17+02:00 Add additional details to evidence bindings Evidence bindings can be all sorts of things, such as type class evidence, a record selector or other builtin constructs such as `Typeable`. - - - - - bb8f0d26 by fendor at 2026-09-16T15:32:23+02:00 Typeable test - - - - - 9 changed files: - + changelog.d/record-dot-evidence - compiler/GHC/Iface/Ext/Ast.hs - compiler/GHC/Iface/Ext/Types.hs - compiler/GHC/Iface/Ext/Utils.hs - testsuite/tests/hiefile/should_run/HasFieldQueries.stdout - + testsuite/tests/hiefile/should_run/HieTypeable.hs - + testsuite/tests/hiefile/should_run/HieTypeable.stdout - testsuite/tests/hiefile/should_run/RecordDotTypes.stdout - testsuite/tests/hiefile/should_run/all.T Changes: ===================================== changelog.d/record-dot-evidence ===================================== @@ -0,0 +1,12 @@ +section: compiler +synopsis: Record selector functions as evidence for `HasField` constraints during .hie file generation. +description: { + We record the record selector `foo` of an expression such as `f.foo` as evidence for + solving the constraint `HasField "foo" record ty`. + + This allows us to point to the definition source location of the record selector `foo`, allowing + users to jump to definition using the evidence variables. +} + +issues: #25418 +mrs: !16694 ===================================== compiler/GHC/Iface/Ext/Ast.hs ===================================== @@ -23,7 +23,6 @@ import GHC.Core.DataCon ( dataConWrapperType ) import GHC.Core.Type ( Type, ForAllTyFlag(..) ) import GHC.Core.TyCon ( TyCon, tyConClass_maybe ) import GHC.Core.InstEnv -import GHC.Core.Predicate ( isEvId ) import GHC.Hs import GHC.Hs.Syn.Type @@ -33,7 +32,7 @@ import GHC.Types.Basic import GHC.Types.UnresolvedImport ( isGeneratedImport ) import GHC.Types.FieldLabel import GHC.Types.Avail ( Avails ) -import GHC.Types.Id ( isDataConId_maybe ) +import GHC.Types.Id ( isDataConId_maybe, isId, idDetails ) import GHC.Types.Name ( Name, nameSrcSpan, nameUnique, wiredInNameTyThing_maybe, getName ) import GHC.Types.Name.Env ( NameEnv, emptyNameEnv, extendNameEnv, lookupNameEnv ) import GHC.Types.Name.Reader ( RecFieldInfo(..), WithUserRdr(..) ) @@ -81,6 +80,7 @@ import Control.Applicative ( (<|>) ) import GHC.Types.TypeEnv ( TypeEnv ) import Control.Arrow ( second ) import Data.Traversable ( mapAccumR ) +import GHC.Types.Id.Info (IdDetails(..), recSelParentName) {- Note [Updating HieAst for changes in the GHC AST] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -682,7 +682,7 @@ instance ToHie (Context (Located (WithUserRdr Name))) where hieEvIdsOfTerm :: EvTerm -> [EvId] -- Returns only EvIds satisfying relevantEvId -hieEvIdsOfTerm = runFVSelectiveList isEvId . evTermFVs +hieEvIdsOfTerm = runFVSelectiveList isId . evTermFVs instance ToHie (EvBindContext (LocatedA TcEvBinds)) where toHie (EvBindContext sc sp (L span (EvBinds bs))) @@ -690,7 +690,7 @@ instance ToHie (EvBindContext (LocatedA TcEvBinds)) where where go evbind = do let evDeps = hieEvIdsOfTerm $ eb_rhs evbind - depNames = EvBindDeps $ map varName evDeps + depNames = EvBindDeps $ map classifyEvBindDep evDeps concatM $ [ toHie (C (EvidenceVarBind (EvLetBind depNames) (combineScopes sc (mkScope span)) sp) (L span $ eb_lhs evbind)) @@ -698,6 +698,12 @@ instance ToHie (EvBindContext (LocatedA TcEvBinds)) where ] toHie _ = pure [] +classifyEvBindDep :: EvId -> EvBindDep +classifyEvBindDep evId = + case idDetails evId of + RecSelId{sel_tycon} -> RecordField (varName evId) (recSelParentName sel_tycon) + _ -> EvidenceVar (varName evId) + instance ToHie (LocatedA HsWrapper) where toHie (L osp wrap) = case wrap of ===================================== compiler/GHC/Iface/Ext/Types.hs ===================================== @@ -598,17 +598,61 @@ instance Outputable EvVarSource where ppr (EvInstBind True cls) = text "bound due to a superclass of " <+> ppr cls ppr (EvLetBind deps) = text "bound by a let, depending on:" <+> ppr deps +data EvBindDep + = EvidenceVar Name + | RecordField Name Name + | TypeableEvidence Name + deriving (Eq, Ord) + +instance Outputable EvBindDep where + ppr = \ case + EvidenceVar n -> ppr n + RecordField sel parent -> ppr sel <+> text "of Record" <+> ppr parent + TypeableEvidence n -> ppr n <+> text "bound by Typeable" + +evBindDepName :: EvBindDep -> Name +evBindDepName = \ case + EvidenceVar n -> n + RecordField selector _record -> selector + TypeableEvidence n -> n + +evBindDepHieName :: EvBindDep -> HieName +evBindDepHieName = toHieName . evBindDepName + +instance Binary EvBindDep where + put_ bh = \ case + EvidenceVar n -> do + putByte bh 0 + put_ bh n + RecordField n sel -> do + putByte bh 1 + put_ bh n + put_ bh sel + TypeableEvidence n -> do + putByte bh 2 + put_ bh n + + get bh = + getByte bh >>= \ case + 0 -> EvidenceVar <$> get bh + 1 -> RecordField <$> get bh <*> get bh + 2 -> TypeableEvidence <$> get bh + t -> fail $ "EvBindDep: Unknown tag: " ++ show t + -- | Eq/Ord instances compare on the converted HieName, -- as non-exported names may have different uniques after -- a roundtrip -newtype EvBindDeps = EvBindDeps { getEvBindDeps :: [Name] } +newtype EvBindDeps = EvBindDeps { getEvBindDeps :: [EvBindDep] } deriving Outputable +evBindDepsNames :: EvBindDeps -> [Name] +evBindDepsNames = map evBindDepName . getEvBindDeps + instance Eq EvBindDeps where - (==) = coerce ((==) `on` map toHieName) + (==) = coerce ((==) `on` map evBindDepHieName) instance Ord EvBindDeps where - compare = coerce (compare `on` map toHieName) + compare = coerce (compare `on` map evBindDepHieName) instance Binary EvBindDeps where put_ bh (EvBindDeps xs) = put_ bh xs ===================================== compiler/GHC/Iface/Ext/Utils.hs ===================================== @@ -145,7 +145,7 @@ getEvidenceTree refmap var = go emptyNameSet var det <- S.toList $ identInfo dets case det of EvidenceVarBind src@(EvLetBind (getEvBindDeps -> xs)) scp spn -> - pure $ Just ((src,scp,spn),mapMaybe (go $ extendNameSet seen var) xs) + pure $ Just ((src,scp,spn),mapMaybe (go (extendNameSet seen var) . evBindDepName) xs) EvidenceVarBind src scp spn -> pure $ Just ((src,scp,spn),[]) _ -> pure Nothing pure $ Tree.Node (EvidenceInfo var sp typ (Just evdet)) children @@ -390,7 +390,7 @@ definedInAsts asts n = case nameSrcSpan n of getEvidenceBindDeps :: ContextInfo -> [Name] getEvidenceBindDeps (EvidenceVarBind (EvLetBind xs) _ _) = - getEvBindDeps xs + evBindDepsNames xs getEvidenceBindDeps _ = [] isEvidenceBind :: ContextInfo -> Bool ===================================== testsuite/tests/hiefile/should_run/HasFieldQueries.stdout ===================================== @@ -3,16 +3,23 @@ At point (13,17), we found: ========================== ┌ │ $dHasField at HasFieldQueries.hs:1:1, of type: HasField "field1" Thing Char -│ is an evidence variable bound by a let, depending on: [C:HasField] +│ is an evidence variable bound by a let, depending on: [C:HasField, +│ field1 of Record Thing] │ with scope: ModuleScope │ │ Defined at <no location info> └ | ++- ┌ +| │ C:HasField at HasFieldQueries.hs:1:1, of type: forall {k} (x :: k) r a. (r -> a) -> HasField x r a +| │ is a usage of an external evidence variable +| │ Defined in `GHC.Internal.Records' +| └ +| `- ┌ - │ C:HasField at HasFieldQueries.hs:1:1, of type: forall {k} (x :: k) r a. (r -> a) -> HasField x r a + │ field1 at HasFieldQueries.hs:1:1, of type: Thing -> Char │ is a usage of an external evidence variable - │ Defined in `GHC.Internal.Records' + │ Defined at HasFieldQueries.hs:9:21 └ ========================== @@ -23,16 +30,23 @@ At point (16,27), we found: ========================== ┌ │ $dHasField at HasFieldQueries.hs:16:1-32, of type: HasField "field1" Thing Char -│ is an evidence variable bound by a let, depending on: [C:HasField] +│ is an evidence variable bound by a let, depending on: [C:HasField, +│ field1 of Record Thing] │ with scope: LocalScope HasFieldQueries.hs:16:1-32 │ bound at: HasFieldQueries.hs:16:1-32 │ Defined at <no location info> └ | ++- ┌ +| │ C:HasField at HasFieldQueries.hs:1:1, of type: forall {k} (x :: k) r a. (r -> a) -> HasField x r a +| │ is a usage of an external evidence variable +| │ Defined in `GHC.Internal.Records' +| └ +| `- ┌ - │ C:HasField at HasFieldQueries.hs:1:1, of type: forall {k} (x :: k) r a. (r -> a) -> HasField x r a + │ field1 at HasFieldQueries.hs:1:1, of type: Thing -> Char │ is a usage of an external evidence variable - │ Defined in `GHC.Internal.Records' + │ Defined at HasFieldQueries.hs:9:21 └ ========================== @@ -40,16 +54,23 @@ At point (23,17), we found: ========================== ┌ │ $dHasField at HasFieldQueries.hs:1:1, of type: HasField "nested1" NestedThing Thing -│ is an evidence variable bound by a let, depending on: [C:HasField] +│ is an evidence variable bound by a let, depending on: [C:HasField, +│ nested1 of Record NestedThing] │ with scope: ModuleScope │ │ Defined at <no location info> └ | ++- ┌ +| │ C:HasField at HasFieldQueries.hs:1:1, of type: forall {k} (x :: k) r a. (r -> a) -> HasField x r a +| │ is a usage of an external evidence variable +| │ Defined in `GHC.Internal.Records' +| └ +| `- ┌ - │ C:HasField at HasFieldQueries.hs:1:1, of type: forall {k} (x :: k) r a. (r -> a) -> HasField x r a + │ nested1 at HasFieldQueries.hs:1:1, of type: NestedThing -> Thing │ is a usage of an external evidence variable - │ Defined in `GHC.Internal.Records' + │ Defined at HasFieldQueries.hs:20:34 └ ========================== @@ -57,16 +78,23 @@ At point (23,25), we found: ========================== ┌ │ $dHasField at HasFieldQueries.hs:1:1, of type: HasField "field1" Thing Char -│ is an evidence variable bound by a let, depending on: [C:HasField] +│ is an evidence variable bound by a let, depending on: [C:HasField, +│ field1 of Record Thing] │ with scope: ModuleScope │ │ Defined at <no location info> └ | ++- ┌ +| │ C:HasField at HasFieldQueries.hs:1:1, of type: forall {k} (x :: k) r a. (r -> a) -> HasField x r a +| │ is a usage of an external evidence variable +| │ Defined in `GHC.Internal.Records' +| └ +| `- ┌ - │ C:HasField at HasFieldQueries.hs:1:1, of type: forall {k} (x :: k) r a. (r -> a) -> HasField x r a + │ field1 at HasFieldQueries.hs:1:1, of type: Thing -> Char │ is a usage of an external evidence variable - │ Defined in `GHC.Internal.Records' + │ Defined at HasFieldQueries.hs:9:21 └ ========================== ===================================== testsuite/tests/hiefile/should_run/HieTypeable.hs ===================================== @@ -0,0 +1,28 @@ +module Main where + +import Data.Dynamic +import Data.Typeable +import TestUtils + +data Thing = Thing {field1 :: Char, field2 :: Bool} + deriving (Show, Eq) + +castFromDynamic :: Dynamic -> Maybe Thing +castFromDynamic d = fromDynamic d + -- ^ this is the point + +rep :: Thing -> TypeRep +rep d = typeOf d + -- ^ this is the point + +points = + [ (11,21) + , (15,10) + ] + +main = do + (df, hf) <- readTestHie "HieTypeable.hie" + let refmap = generateReferencesMap $ getAsts $ hie_asts hf + + traverse (explainEv df hf refmap) points + return () ===================================== testsuite/tests/hiefile/should_run/HieTypeable.stdout ===================================== @@ -0,0 +1,30 @@ +========================== +At point (11,21), we found: +========================== +┌ +│ $dTypeable at HieTypeable.hs:1:1, of type: Typeable Thing +│ is an evidence variable bound by a let, depending on: [$dTypeable] +│ with scope: ModuleScope +│ +│ Defined at <no location info> +└ +| +`- ┌ + │ $dTypeable at HieTypeable.hs:1:1, of type: Typeable Thing + │ is an evidence variable bound by a let, depending on: [] + │ with scope: ModuleScope + │ + │ Defined at <no location info> + └ + +========================== +At point (15,10), we found: +========================== +┌ +│ $dTypeable at HieTypeable.hs:1:1, of type: Typeable Thing +│ is an evidence variable bound by a let, depending on: [] +│ with scope: ModuleScope +│ +│ Defined at <no location info> +└ + ===================================== testsuite/tests/hiefile/should_run/RecordDotTypes.stdout ===================================== @@ -1,9 +1,9 @@ At (22,6), got type: MyRecord At (22,20), got type: MyRecord -> Integer At (22,25), got type: MyRecord -At (22,28), got type: MyChild -> String -At (22,29), got type: MyChild -> String -At (22,6) - (22,8), got type: String +At (22,28), got type: MyChild -> [Char] +At (22,29), got type: MyChild -> [Char] +At (22,6) - (22,8), got type: [Char] At (22,17) - (22,20), got type: Integer At (22,25) - (22,27), got type: MyChild -At (22,25) - (22,29), got type: String +At (22,25) - (22,29), got type: [Char] ===================================== testsuite/tests/hiefile/should_run/all.T ===================================== @@ -11,3 +11,4 @@ test('T24544', [extra_run_opts('"' + config.libdir + '"'), extra_files(['TestUti test('HieGadtConSigs', [extra_run_opts('"' + config.libdir + '"'), extra_files(['TestUtils.hs'])], compile_and_run, ['-package ghc -fwrite-ide-info']) test('T25709', [extra_run_opts('"' + config.libdir + '"'), extra_files(['TestUtils.hs'])], compile_and_run, ['-package ghc -fwrite-ide-info']) test('HasFieldQueries', [extra_run_opts('"' + config.libdir + '"'), extra_files(['TestUtils.hs'])], compile_and_run, ['-package ghc -fwrite-ide-info']) +test('HieTypeable', [extra_run_opts('"' + config.libdir + '"'), extra_files(['TestUtils.hs'])], compile_and_run, ['-package ghc -fwrite-ide-info']) View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/1793ebd827282dcd8e6900e798cca0… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/1793ebd827282dcd8e6900e798cca0… You're receiving this email because of your account on gitlab.haskell.org. 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[Git][ghc/ghc][wip/jeltsch/improve-closure-property-check] Remove class instantiations for `GlobalUnitKey`
by Wolfgang Jeltsch (＠jeltsch) 16 Sep '26

16 Sep '26

Wolfgang Jeltsch pushed to branch wip/jeltsch/improve-closure-property-check at Glasgow Haskell Compiler / GHC Commits: 8134bb63 by Wolfgang Jeltsch at 2026-09-16T16:35:58+03:00 Remove class instantiations for `GlobalUnitKey` - - - - - 1 changed file: - compiler/GHC/Unit/External/Index.hs Changes: ===================================== compiler/GHC/Unit/External/Index.hs ===================================== @@ -308,7 +308,6 @@ data GlobalUnitKey = GlobalUnitKey !UnitId -- ^ Unit Id of the 'UnitInfo' !UnitAbiHash -- ^ ABI hash of the 'UnitInfo' - deriving (Eq, Ord) globalUnitKeyFromUnitInfo :: UnitInfo -> GlobalUnitKey globalUnitKeyFromUnitInfo ui = mkGlobalUnitKey (unitId ui) (unitAbiHash ui) View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/8134bb633f49a0de1abee88a7a79dcf… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/8134bb633f49a0de1abee88a7a79dcf… 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/dcoutts/io-manager-feature-bitset] 25 commits: ci: Actually pass --ignore-perf-failures to the testsuite driver
by Duncan Coutts (＠dcoutts) 16 Sep '26

16 Sep '26

Duncan Coutts pushed to branch wip/dcoutts/io-manager-feature-bitset at Glasgow Haskell Compiler / GHC Commits: 4e9297ea by Simon Jakobi at 2026-09-11T08:32:45-04:00 ci: Actually pass --ignore-perf-failures to the testsuite driver 684c0018d9 changed the IGNORE_PERF_FAILURES handling to append to RUNTEST_ARGS with bash array syntax, but the three use sites still expand RUNTEST_ARGS as a scalar, which yields only the first array element. The appended flag was therefore dropped in every job, so perf improvements kept failing Marge Bot batches and master pipelines, contrary to #19562. Append as a string instead, matching the existing --force-colors append in test_hadrian. Fixes #27563. Assisted-by: Claude Fable 5.1 - - - - - 4f78dfdf by Simon Jakobi at 2026-09-11T08:33:24-04:00 testsuite: Give T26537 a 1.5x compile timeout Its -fregs-graph compile step tends to time out in unoptimized builds (#27188, #27776). Assisted-by: Claude Fable 5.1 - - - - - 130286e3 by Alan Zimmerman at 2026-09-11T08:34:08-04:00 EPA: Remove ListBanana / ListParens from AnnListBrackets This is a step towards making AnnList only represent lists of items which can have either braces or layout. - - - - - a9827d13 by Simon Jakobi at 2026-09-11T18:53:32-04:00 Reject ~, UNPACK and multiplicity annotations on type data fields Only `!` was rejected so far. `~`, UNPACK and multiplicity annotations were silently accepted. None of them make sense at the type level, so restriction (R3) of Note [Type data declarations] now covers all of them. Fixes #27732. Assisted-by: Claude Fable 5.1 - - - - - c71d5e23 by Alan Zimmerman at 2026-09-11T18:54:11-04:00 EPA: Add a Note for the exact print main loop - - - - - 7a108e43 by Simon Jakobi at 2026-09-12T18:35:59-04:00 FastString: Drop mkFastStringWith's constructor callback All three callers passed the same callback, a partial application of mkNewFastStringShortByteString to the string being interned. That partial application is allocated as a closure before the table lookup, on the common hit path too, although the callback is needed only after a miss. Drop the parameter and call mkNewFastStringShortByteString directly after a miss. Since nothing is passed "with" anymore, rename the function to internSB. Suggested by Simon PJ in #27528: https://gitlab.haskell.org/ghc/ghc/-/work_items/27528#note_687031 Assisted-by: Claude Fable 5 - - - - - 82c73b22 by Alan Zimmerman at 2026-09-12T18:36:38-04:00 EPA: More targeted HsDo exact print annotation HsDo is multi-purpose, as encoded in its HsDoFlavour field. Some of these are in a layout context (DoExpr, MDoExpr), others are not (ListComp, MonadComp). We are moving towards using AnnList only in layout contexts, so we switch the HsDo TTG annotation from holding an AnnList for this, to holding Either (EpToken "[", EpToken "]") AnnList This also allows us to trim down AnnListBrackets to only have braces or None, thereby opening the door for unification with the existing layout context data type EpLayout. - - - - - 749d2448 by Luite Stegeman at 2026-09-15T14:07:01-04:00 rts: handle large CONSTR closures in compacting GC The function update_fwd_large in the compacting GC could run into an unexpected object with the following error: internal error: update_fwd_large: unknown/strange object 1 Closure type 1 is CONSTR. This patch adds cases for CONSTR and CONSTR_NOCAF. This is the same problem as #27434 (large AP closures, fixed by cca0d58963), which missed this case. Fixes #27649 - - - - - 177d6155 by Luite Stegeman at 2026-09-15T14:07:02-04:00 testsuite: fix T27434 test with compacting GC Ensure that the interpreter is actually run with the compacting GC - - - - - 5796aa63 by Luite Stegeman at 2026-09-15T14:07:49-04:00 rts: initialise the stack frame header for mask_frame and apply_mask_frame We must leave the stack in consistent state before jumping to mask_frame or apply_mask_frame because they may result. Failing to do so could lead to a crash if there were waiting exceptions. Fixes #27651 - - - - - 2486cc92 by Simon Peyton Jones at 2026-09-15T14:08:36-04:00 Re-introduce the "weird SpecDict" case In this commit commit f80375dd4945350a1d784e436975b48b9c736eaf Author: Simon Peyton Jones <simon.peytonjones(a)gmail.com> Date: Sun Jun 29 15:26:58 2025 +0100 Refactor of Specialise.hs I removed a test for a dictionary with unbound type variables. This turned out to be wrong; see #27629. So this MR re-introduces it. - - - - - 8e09a46f by Duncan Coutts at 2026-09-15T20:11:35-04:00 Refactor (and rename) removeFromQueues, to simplify I/O managers Rename it to unblockAndAppendToRunQueue which better reflects what it is intended to do. The post-condition for unblockAndAppendToRunQueue is that the TSO is on the run queue or it is in the process of migrating to another cap. Previously it achieved that by always directly adding the TSO to the run queue itself. But this actually made things more complicated for the I/O managers, because it meant they needed a separate code path for notifying for cancellation compared to notifying for completion. The general notification code would always add the TSO to the run queue itself. So the improvement is to allow different cases in unblockAndAppendToRunQueue to achieve the same outcome in different ways: either directly adding to the run queue or calling helper functions that do so themselves. This then allows the new I/O managers to share code between the sync and async cancellation, and to reuse their notifyIOCompletion helpers for cancellation. This avoids a source of bugs where the completion path may be updated but the cancellation path may be forgotten, or similarly in future for sync/async operations. Update all the existing in-RTS I/O managers, and the posix timeout code. - - - - - d668782c by Duncan Coutts at 2026-09-15T20:11:35-04:00 Document that awaitCompletedTimeoutsOrIO expects an empty run queue This was true before but implicit and not relied on much. It's better to be explicit, and allow things to depend on it. - - - - - 11d938bb by Duncan Coutts at 2026-09-15T20:11:35-04:00 Store the I/O opcode and fd in the StgAsyncIOOp This will be useful in several I/O managers and it is handy for logging and debugging. It also doesn't increase the size of the StgAsyncIOOp structure. There was enough spare padding space already. Update the poll I/O manager to set the new fields. Add a helper function to convert the enum IOReadOrWrite into the enum IOOpCode. Also change IOReadOrWrite to be an enum without a typedef, for consistency with other enumerations in IOManager.h - - - - - bfa87882 by Duncan Coutts at 2026-09-15T20:11:36-04:00 Add a new I/O manager based on select() Yes, this is the second such I/O manager, but it is a modern re-implementation based on the new in-RTS I/O manager infrastructure. So it is cleaner and faster than the old select I/O manager. Why do we need another I/O manager based on select? Why isn't the poll() one good enough as a baseline portable unix I/O manager? Because macOS. Apple Inc. is why we cannot have nice things. The man page for poll on macOS documents the fact that it does not work. At least, it does not work for all files. Specifically, it does not work for device files. Whereas macOS select() does work for device files. Aaaaarg! We _do_ want to deprecate and remove the old select I/O manager, but due to macOS we cannot do that until we have a replacement. This is that replacement. Until of course a nice new k-queue I/O manager arrives, which could become the new default for macOS and FreeBSD. Interestingly, this select I/O manager is actually faster than the poll one, on Linix, in some circumstances: specifically when many Haskell threads are waiting on the same fd. The poll I/O manager does O(n) work for n threads waiting on I/O, whereas the select one does O(fds) work for the number of fds that threads are waiting on. Usually this is 1:1, so it's not noticable, but one can concoct extreme benchmarks to show the difference. - - - - - 8e9de15a by Duncan Coutts at 2026-09-15T20:11:36-04:00 Minor updates in the poll I/O manager to keep in sync with select This keeps it in sync with select one. The changes are based on code review while implementing the new select I/O manager. The two I/O managers are so similar in structure that it makes sense to try to minimise the diff between them. This should aid understanding, and fixes to both in future. - - - - - 222668bb by Duncan Coutts at 2026-09-15T20:11:36-04:00 Document the new select I/O manager in the user guide in the RTS section about I/O managers. And add a changelog entry. - - - - - 0f48735b by Cheng Shao at 2026-09-15T20:12:23-04:00 Revert "wasm: workaround WebKit bug in dyld" This reverts commit c9b8465c2c338176fcab9d197e9d31f4aee11f68. The underlying webkit bug has been fixed in https://commits.webkit.org/314219@main. Closes #27564. - - - - - 809294f1 by Luite Stegeman at 2026-09-15T20:13:08-04:00 rts: make stg_threadLabelzh return a valid pointer for unlabeled threads. This fixes a segfault in the GC caused by stg_threadLabelzh returning a 0 pointer in a GC pointer field. stg_threadLabelzh returns a tuple of type (# Int#, ByteArray# #). If a thread has no label, the second field is unused. We must still return a valid heap object pointer. Instead of returning 0, we now return stg_DEAD_SLOT_closure. fixes #27618 - - - - - e2d57026 by Luite Stegeman at 2026-09-15T20:13:54-04:00 JS: fix selector thunk handling fix a bug where entering a selector thunk could lead to a crash if the selected field was still a thunk. fixes #27788 - - - - - f8a7e988 by Duncan Coutts at 2026-09-16T13:38:38+01:00 Fix a couple comments in the new selectbis I/O manager Noticed late in the review process. - - - - - 8272e000 by Duncan Coutts at 2026-09-16T13:38:38+01:00 New rts_IOManagerFeatures bitset for I/O manager features The idea is that code in the RTS and ghc-internal can use this feature bitset to do things that have to be conditional. But instead of basing it on threaded/non-threaded, win32 etc it can be based on features of the current I/O manager. In particular this will allow us to have in-RTS I/O managers when using the threaded RTS way, by changing code to use the feature test rather than testing for threaded/non-threaded. There are also numerous conditions in existing RTS and library code that could benefit from being clearly based on I/O manager features rather than on (historically) correlated aspects of the platform. For example, a major difference between WinIO and the win32-legacy I/O manager is whether it uses C lib fds or Win32 API HANDLEs. This distinction is not necessarily unique forever to these I/O managers. Future Windows I/O managers may want to take advantage of the same distinction. For example, we could have a feature to say if the I/O manager supports readiness notifications threadWaitRead# etc (win32-legacy does not support these for example), so I/O code in ghc-internal can use appropriate workarounds. Similarly, if/when we add support for async I/O, or I/O to files at given offsets (without affecting or being affected by the file pointer) then library code can consult the feature bits and either use emulated fallbacks or throw appropriate exceptions. - - - - - 6f859ae2 by Duncan Coutts at 2026-09-16T13:38:38+01:00 Use rts_IOManagerFeatures bitset in GHC.Internal.IO.SubSystem Establish a pattern for exposing the features. We will start using them in subsequent commits. - - - - - 7c8a4f79 by Duncan Coutts at 2026-09-16T13:38:38+01:00 Turn rts_IOManagerIsWin32Native into a feature bit of rts_IOManagerFeatures And update where it is used in ghc-internal - - - - - 02d23436 by Duncan Coutts at 2026-09-16T13:38:38+01:00 Remove is_io_mng_native_p helper, replacing with iomgr_type The comment said: Temporary compat helper function used in the Win32 I/O managers. TODO: replace by consulting the iomgr_type global instead. - - - - - 89 changed files: - .gitlab/ci.sh - + changelog.d/27732 - + changelog.d/T27629 - + changelog.d/T27788-js-selector - + changelog.d/fix-compacting-gc-constr-27649 - + changelog.d/fix-control0-mask-trampoline - + changelog.d/fix-threadlabel-segfault-27618 - + changelog.d/select-io-manager - compiler/GHC/Core/Opt/Specialise.hs - compiler/GHC/Data/FastString.hs - compiler/GHC/Hs/Expr.hs - compiler/GHC/Hs/Pat.hs - compiler/GHC/Hs/Utils.hs - compiler/GHC/Parser.y - compiler/GHC/Parser/Annotation.hs - compiler/GHC/Parser/PostProcess.hs - compiler/GHC/Rename/Module.hs - compiler/GHC/StgToJS/Apply.hs - compiler/GHC/StgToJS/Symbols.hs - compiler/GHC/Tc/Errors/Types.hs - docs/users_guide/exts/type_data.rst - docs/users_guide/runtime_control.rst - libraries/base/src/GHC/RTS/Flags.hs - libraries/ghc-internal/src/GHC/Internal/IO/SubSystem.hs - libraries/ghc-internal/src/GHC/Internal/RTS/Flags.hsc - rts/ContinuationOps.cmm - rts/IOManager.c - rts/IOManager.h - rts/IOManagerInternals.h - rts/PrimOps.cmm - rts/RaiseAsync.c - rts/RtsStartup.c - rts/RtsSymbols.c - rts/StgMiscClosures.cmm - rts/configure.ac - rts/include/rts/Flags.h - rts/include/rts/storage/Closures.h - rts/include/stg/MiscClosures.h - rts/posix/Poll.c - rts/posix/Poll.h - + rts/posix/SelectBis.c - + rts/posix/SelectBis.h - rts/posix/Timeout.c - rts/posix/Timeout.h - rts/rts.cabal - rts/sm/Compact.c - rts/win32/AwaitEvent.c - rts/win32/ThrIOManager.c - testsuite/tests/codeGen/should_run/all.T - testsuite/tests/ghc-api/T25121_status.stdout - testsuite/tests/interface-stability/ghc-experimental-exports.stdout - testsuite/tests/interface-stability/ghc-experimental-exports.stdout-mingw32 - + testsuite/tests/javascript/T27788.hs - + testsuite/tests/javascript/T27788.stdout - testsuite/tests/javascript/all.T - testsuite/tests/parser/should_compile/DumpParsedAstComments.stderr - testsuite/tests/parser/should_compile/DumpSemis.stderr - testsuite/tests/printer/Test20297.stdout - + testsuite/tests/rts/T27618.hs - + testsuite/tests/rts/T27618.stdout - + testsuite/tests/rts/T27649.hs - + testsuite/tests/rts/T27649.stdout - testsuite/tests/rts/all.T - + testsuite/tests/rts/continuations/T27651.hs - + testsuite/tests/rts/continuations/T27651.stdout - testsuite/tests/rts/continuations/all.T - testsuite/tests/simplCore/should_compile/Makefile - + testsuite/tests/simplCore/should_compile/T27629.hs - + testsuite/tests/simplCore/should_compile/T27629.stderr - + testsuite/tests/simplCore/should_compile/T27629Plugin.hs - testsuite/tests/simplCore/should_compile/all.T - + 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/T27732e.hs - + testsuite/tests/type-data/should_fail/T27732e.stderr - + testsuite/tests/type-data/should_fail/T27732f.hs - + testsuite/tests/type-data/should_fail/T27732f.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 - utils/check-exact/ExactPrint.hs - utils/check-exact/Utils.hs - utils/jsffi/dyld.mjs The diff was not included because it is too large. View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/8804d9944d9cb39ce6f5fc48d8e7fd… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/8804d9944d9cb39ce6f5fc48d8e7fd… 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/io-manager-deadlock-detection] 39 commits: ci: Actually pass --ignore-perf-failures to the testsuite driver
by Duncan Coutts (＠dcoutts) 16 Sep '26

16 Sep '26

Duncan Coutts pushed to branch wip/io-manager-deadlock-detection at Glasgow Haskell Compiler / GHC Commits: 4e9297ea by Simon Jakobi at 2026-09-11T08:32:45-04:00 ci: Actually pass --ignore-perf-failures to the testsuite driver 684c0018d9 changed the IGNORE_PERF_FAILURES handling to append to RUNTEST_ARGS with bash array syntax, but the three use sites still expand RUNTEST_ARGS as a scalar, which yields only the first array element. The appended flag was therefore dropped in every job, so perf improvements kept failing Marge Bot batches and master pipelines, contrary to #19562. Append as a string instead, matching the existing --force-colors append in test_hadrian. Fixes #27563. Assisted-by: Claude Fable 5.1 - - - - - 4f78dfdf by Simon Jakobi at 2026-09-11T08:33:24-04:00 testsuite: Give T26537 a 1.5x compile timeout Its -fregs-graph compile step tends to time out in unoptimized builds (#27188, #27776). Assisted-by: Claude Fable 5.1 - - - - - 130286e3 by Alan Zimmerman at 2026-09-11T08:34:08-04:00 EPA: Remove ListBanana / ListParens from AnnListBrackets This is a step towards making AnnList only represent lists of items which can have either braces or layout. - - - - - a9827d13 by Simon Jakobi at 2026-09-11T18:53:32-04:00 Reject ~, UNPACK and multiplicity annotations on type data fields Only `!` was rejected so far. `~`, UNPACK and multiplicity annotations were silently accepted. None of them make sense at the type level, so restriction (R3) of Note [Type data declarations] now covers all of them. Fixes #27732. Assisted-by: Claude Fable 5.1 - - - - - c71d5e23 by Alan Zimmerman at 2026-09-11T18:54:11-04:00 EPA: Add a Note for the exact print main loop - - - - - 7a108e43 by Simon Jakobi at 2026-09-12T18:35:59-04:00 FastString: Drop mkFastStringWith's constructor callback All three callers passed the same callback, a partial application of mkNewFastStringShortByteString to the string being interned. That partial application is allocated as a closure before the table lookup, on the common hit path too, although the callback is needed only after a miss. Drop the parameter and call mkNewFastStringShortByteString directly after a miss. Since nothing is passed "with" anymore, rename the function to internSB. Suggested by Simon PJ in #27528: https://gitlab.haskell.org/ghc/ghc/-/work_items/27528#note_687031 Assisted-by: Claude Fable 5 - - - - - 82c73b22 by Alan Zimmerman at 2026-09-12T18:36:38-04:00 EPA: More targeted HsDo exact print annotation HsDo is multi-purpose, as encoded in its HsDoFlavour field. Some of these are in a layout context (DoExpr, MDoExpr), others are not (ListComp, MonadComp). We are moving towards using AnnList only in layout contexts, so we switch the HsDo TTG annotation from holding an AnnList for this, to holding Either (EpToken "[", EpToken "]") AnnList This also allows us to trim down AnnListBrackets to only have braces or None, thereby opening the door for unification with the existing layout context data type EpLayout. - - - - - 749d2448 by Luite Stegeman at 2026-09-15T14:07:01-04:00 rts: handle large CONSTR closures in compacting GC The function update_fwd_large in the compacting GC could run into an unexpected object with the following error: internal error: update_fwd_large: unknown/strange object 1 Closure type 1 is CONSTR. This patch adds cases for CONSTR and CONSTR_NOCAF. This is the same problem as #27434 (large AP closures, fixed by cca0d58963), which missed this case. Fixes #27649 - - - - - 177d6155 by Luite Stegeman at 2026-09-15T14:07:02-04:00 testsuite: fix T27434 test with compacting GC Ensure that the interpreter is actually run with the compacting GC - - - - - 5796aa63 by Luite Stegeman at 2026-09-15T14:07:49-04:00 rts: initialise the stack frame header for mask_frame and apply_mask_frame We must leave the stack in consistent state before jumping to mask_frame or apply_mask_frame because they may result. Failing to do so could lead to a crash if there were waiting exceptions. Fixes #27651 - - - - - 2486cc92 by Simon Peyton Jones at 2026-09-15T14:08:36-04:00 Re-introduce the "weird SpecDict" case In this commit commit f80375dd4945350a1d784e436975b48b9c736eaf Author: Simon Peyton Jones <simon.peytonjones(a)gmail.com> Date: Sun Jun 29 15:26:58 2025 +0100 Refactor of Specialise.hs I removed a test for a dictionary with unbound type variables. This turned out to be wrong; see #27629. So this MR re-introduces it. - - - - - 8e09a46f by Duncan Coutts at 2026-09-15T20:11:35-04:00 Refactor (and rename) removeFromQueues, to simplify I/O managers Rename it to unblockAndAppendToRunQueue which better reflects what it is intended to do. The post-condition for unblockAndAppendToRunQueue is that the TSO is on the run queue or it is in the process of migrating to another cap. Previously it achieved that by always directly adding the TSO to the run queue itself. But this actually made things more complicated for the I/O managers, because it meant they needed a separate code path for notifying for cancellation compared to notifying for completion. The general notification code would always add the TSO to the run queue itself. So the improvement is to allow different cases in unblockAndAppendToRunQueue to achieve the same outcome in different ways: either directly adding to the run queue or calling helper functions that do so themselves. This then allows the new I/O managers to share code between the sync and async cancellation, and to reuse their notifyIOCompletion helpers for cancellation. This avoids a source of bugs where the completion path may be updated but the cancellation path may be forgotten, or similarly in future for sync/async operations. Update all the existing in-RTS I/O managers, and the posix timeout code. - - - - - d668782c by Duncan Coutts at 2026-09-15T20:11:35-04:00 Document that awaitCompletedTimeoutsOrIO expects an empty run queue This was true before but implicit and not relied on much. It's better to be explicit, and allow things to depend on it. - - - - - 11d938bb by Duncan Coutts at 2026-09-15T20:11:35-04:00 Store the I/O opcode and fd in the StgAsyncIOOp This will be useful in several I/O managers and it is handy for logging and debugging. It also doesn't increase the size of the StgAsyncIOOp structure. There was enough spare padding space already. Update the poll I/O manager to set the new fields. Add a helper function to convert the enum IOReadOrWrite into the enum IOOpCode. Also change IOReadOrWrite to be an enum without a typedef, for consistency with other enumerations in IOManager.h - - - - - bfa87882 by Duncan Coutts at 2026-09-15T20:11:36-04:00 Add a new I/O manager based on select() Yes, this is the second such I/O manager, but it is a modern re-implementation based on the new in-RTS I/O manager infrastructure. So it is cleaner and faster than the old select I/O manager. Why do we need another I/O manager based on select? Why isn't the poll() one good enough as a baseline portable unix I/O manager? Because macOS. Apple Inc. is why we cannot have nice things. The man page for poll on macOS documents the fact that it does not work. At least, it does not work for all files. Specifically, it does not work for device files. Whereas macOS select() does work for device files. Aaaaarg! We _do_ want to deprecate and remove the old select I/O manager, but due to macOS we cannot do that until we have a replacement. This is that replacement. Until of course a nice new k-queue I/O manager arrives, which could become the new default for macOS and FreeBSD. Interestingly, this select I/O manager is actually faster than the poll one, on Linix, in some circumstances: specifically when many Haskell threads are waiting on the same fd. The poll I/O manager does O(n) work for n threads waiting on I/O, whereas the select one does O(fds) work for the number of fds that threads are waiting on. Usually this is 1:1, so it's not noticable, but one can concoct extreme benchmarks to show the difference. - - - - - 8e9de15a by Duncan Coutts at 2026-09-15T20:11:36-04:00 Minor updates in the poll I/O manager to keep in sync with select This keeps it in sync with select one. The changes are based on code review while implementing the new select I/O manager. The two I/O managers are so similar in structure that it makes sense to try to minimise the diff between them. This should aid understanding, and fixes to both in future. - - - - - 222668bb by Duncan Coutts at 2026-09-15T20:11:36-04:00 Document the new select I/O manager in the user guide in the RTS section about I/O managers. And add a changelog entry. - - - - - 0f48735b by Cheng Shao at 2026-09-15T20:12:23-04:00 Revert "wasm: workaround WebKit bug in dyld" This reverts commit c9b8465c2c338176fcab9d197e9d31f4aee11f68. The underlying webkit bug has been fixed in https://commits.webkit.org/314219@main. Closes #27564. - - - - - 809294f1 by Luite Stegeman at 2026-09-15T20:13:08-04:00 rts: make stg_threadLabelzh return a valid pointer for unlabeled threads. This fixes a segfault in the GC caused by stg_threadLabelzh returning a 0 pointer in a GC pointer field. stg_threadLabelzh returns a tuple of type (# Int#, ByteArray# #). If a thread has no label, the second field is unused. We must still return a valid heap object pointer. Instead of returning 0, we now return stg_DEAD_SLOT_closure. fixes #27618 - - - - - e2d57026 by Luite Stegeman at 2026-09-15T20:13:54-04:00 JS: fix selector thunk handling fix a bug where entering a selector thunk could lead to a crash if the selected field was still a thunk. fixes #27788 - - - - - 82ca0dc9 by Duncan Coutts at 2026-09-16T06:52:02+01:00 Make signal handling be a responsibility of the I/O manager(s) Previously it was scattered between I/O managers and the scheduler, and especially the scheduler's deadlock detection. Previously the scheduler would poll for pending signals each iteration of the scheduler loop. The scheduler also had some hairy signal functionality in the deadlock detection: in the non-threaded RTS (only) if there were still no threads running after deadlock detection then it would block waiting for signals. But signals can and (in my opinion) should be thought of as just a funny kind of I/O, and thus should be a responsibility of the I/O manager. So now we have the I/O managers poll for signals when they are polling for I/O completion (and removing the separate poll in the scheduler). And when I/O managers block waiting for I/O then they now also start signal handlers if they get interrupted by a signal. Crucially, if there is no pending I/O or timers, the awaitCompletedTimeoutsOrIO will still block waiting for signals. This patch puts us into an intermediate state: it temporarily breaks deadlock detection in the non-threaded RTS. The waiting on I/O currently happens before deadlock detection. This means we'll now wait forever on signals before doing deadlock detection. We need to move waiting after deadlock detection. We'll do that in a later patch. - - - - - ddfe4e39 by Duncan Coutts at 2026-09-16T06:52:02+01:00 Clean up the RTS internal signal handling API Now that the I/O manager is responsible for signals, we can simplify the API we present for signal handling. We now just need startPendingSignalHandlers, which is called from the I/O managers. We can get rid of awaitUserSignals. We also don't need RtsSignals.h to re-export the platform-specific posix/Signals.h or win32/ConsoleHandler.h We can also hide more of the implementation of signals. Less has to be exposed in posix/Signals.h or win32/ConsoleHandler.h. Indeed, posix/Signals.h becomes empty and we remove it. Partly this is because we don't need inline functions (or macros) in the interface. Also remove signal_handlers from RTS ABI exported symbols list. It does not appear to have any users in the core libs, and its really an internal implementation detail. It should not be exposed unless it's really necessary. - - - - - 33029f9b by Duncan Coutts at 2026-09-16T06:52:02+01:00 In the scheduler, move I/O blocking after deadlock detection To make deadlock detection effective in the non-threaded RTS when there are deadlocked threads and other unrelated threads waiting on I/O, we need to arrange to do deadlock detection before we block in scheduler to wait on I/O. The solution is to: 1. adjust scheduleFindWork, which runs before deadlock detection, to only poll for I/O and not block; and 2. add a step after deadlock detection to wait on I/O if there are still no threads to run (and there's any I/O or timeouts outstanding) The scheduleCheckBlockedThreads is now so simple that it made more sense to inline it into scheduleFindWork. - - - - - 94401957 by Duncan Coutts at 2026-09-16T06:52:02+01:00 Remove bogus anyPendingTimeoutsOrIO guard from scheduleDetectDeadlock The deadlock detection was only invoked if both of these conditions hold: 1. the run queue is empty 2. there is no pending I/O or timeouts The second condition is unnecessary. The deadlock detection mechanism can find deadlocks even if there are other threads waiting on I/O or timers. Having this extra condition means that we fail to detect blocked threads if there are any threads waiting on I/O or timers. Part of fixing issue #26408 - - - - - 575632ad by Duncan Coutts at 2026-09-16T06:52:02+01:00 Don't consider pending I/O for early context switch optimisation Context switches are normally initiated by the timer signal. If however the user specifies "context switch as often as possible", with +RTS -C0 then the scheduler arranges for an early context switch (when it's just about to run a Haskell thread). Context switching very often is expensive, so as an optimisation there cases where we do not arrange an early context switch: 1. if there's no other threads to run 2. if there is no pending I/O or timers This patch eliminates case 2, leaving only case 1. The rationale is as follows. The use of this was inconsistent across platforms and threaded/non-threaded RTS ways. It only worked on the non-threaded RTS and on Windows only worked for the win32-legacy I/O manager. On all other combinations anyPendingTimeoutsOrIO would always return false. The fact that nobody noticed and complained about this inconsistency suggests that the feature is not relied upon. If however it turns out that applications do rely on this, then the proper thing to do is not to restore this check, but to add a new I/O manager hint function that returns if there is any pending events that are likely to happen *soon*: for example timeouts expiring within one timeslice, or I/O waits on things likely to complete soon like disk I/O, but not for example socket/pipe I/O. The motivation to avoid this use of anyPendingTimeoutsOrIO is to allow us to eliminate anyPendingTimeoutsOrIO entirely. All other uses of this are just guards on {await,poll}CompletedTimeoutsOrIO and the guards can safely be folded into those functions. This will better cope with some I/O managers having no proper implementation of anyPendingTimeoutsOrIO. Ultimately this will let us simplify the scheduler which currently has to have special #ifdef mingw32_HOST_OS cases to cope with the lack of a working anyPendingTimeoutsOrIO for some Windows I/O managers - - - - - babfba3d by Duncan Coutts at 2026-09-16T06:52:02+01:00 Remove anyPendingTimeoutsOrIO guarding {poll,await}CompletedTimeoutsOrIO Previously the API of the I/O manager used a two step process: check anyPendingTimeoutsOrIO and then call {poll,await}CompletedTimeoutsOrIO. This was primarily there as a performance thing, to cheaply check if we need to do anything. And then because anyPendingTimeoutsOrIO existed, it was used for other things too. We have now eliminated the other uses, and are just left with the performance pattern. But this was problematic because not all I/O managers correctly implement anyPendingTimeoutsOrIO (specifically the win32 ones), and now that we also make I/O managers responsible for signals then we need to poll/await even if there is no pending I/O or timeouts. If there is no pending I/O or timeouts then await needs to degenerate to just waiting forever for any signals. - - - - - cb4fefc8 by Duncan Coutts at 2026-09-16T06:52:02+01:00 Remove anyPendingTimeoutsOrIO, it is no longer used And this avoids the problems arising from the win32 I/O managers having had a bogus implementation. - - - - - dcb8cc08 by Duncan Coutts at 2026-09-16T06:52:02+01:00 Remove second scheduler call to awaitCompletedTimeoutsOrIO Previously awaitCompletedTimeoutsOrIO was called both before and after deadlock detection in the scheduler. The reason for that was that the win32 I/O managers had a bogus implementation of anyPendingTimeoutsOrIO and this was used to guard the call of awaitCompletedTimeoutsOrIO prior to deadlock detection. This meant the first call site was never actually called when using the win32 I/O managers. This was the reason for the second call: the first one was never used. What a mess. So now we have a simple design in the scheduler: 1. poll for completed I/O, timers or signals 2. if no runnable threads: do deadlock detection 3. if still no runnable threads: block waiting for I/O, timers or signals. - - - - - 9115d88f by Duncan Coutts at 2026-09-16T06:52:02+01:00 Lift emptyRunQueue guard out of scheduleDetectDeadlock this improved the clarity of the logic when reading the scheduler code. - - - - - fddbaf83 by Duncan Coutts at 2026-09-16T06:52:02+01:00 Make non-threaded deadlock detection also rely on idle GC Only do deadlock detection GC when idle GC kicks in. This also relies on using wakeUpRts, so now do this unconditionally. Previously wakeUpRts was for the threaded rts only. - - - - - fafa5d3e by Duncan Coutts at 2026-09-16T06:52:02+01:00 Enable idle GC by default on non-threaded RTS The behaviour is now uniform between the threaded and non-threaded RTS ways. The deadlock detection now relies on idle GC for both threaded and non-threaded ways. Previously deadlock detection did not rely on idle GC for the non-threaded way. Also tweak test T7275 to account for idle GC. This test's output is sensitive to the number of major GCs run. Since this commit enables idle GC for the non-threaded RTS, for this test that increases the number of major GCs, since the test program is frequently idle for more than 300ms. - - - - - 2c92ab6e by Duncan Coutts at 2026-09-16T06:52:02+01:00 Fix state of idle GC control vars with +RTS -V0 Currently when the user uses +RTS -I0, then doIdleGC is set to false. But if the master tick interval -V is set to 0 then the idleGCDelayTime was being set to 0 but doIdleGC was not being set to false, which is inconsistent, and almost certainly buggy. - - - - - 39c5246b by Duncan Coutts at 2026-09-16T06:52:02+01:00 Add a long Note [Deadlock detection] It describes the historical and modern designs and their trade-offs. The point is we've now unified the code for deadlock detection between the threaded and non-threaded ways, by changing the non-threaded to follow the same design as the threaded. - - - - - 4f6abab9 by Duncan Coutts at 2026-09-16T06:52:02+01:00 Add a test for deadlock detection, issue #26408 - - - - - 88d6a2f6 by Duncan Coutts at 2026-09-16T06:52:02+01:00 Update the user guide with the revised idle GC behaviour i.e. it's now not just for the threaded RTS, but general. Also document the fact that disabling idle GC also disables deadlock detection. And add a changelog entry. - - - - - 8402a41c by Duncan Coutts at 2026-09-16T06:52:02+01:00 Move idle GC tracking to its own file, step 1 of 2 Add a new IdleGC.{c,h} module. Move the RecentActivity type, recent_activity variable and {get,set}RecentActivity wrappers. - - - - - e729131f by Duncan Coutts at 2026-09-16T06:52:02+01:00 Move idle GC functionality to its own file, step 2 of 2 We can now fully encapsulate the recent_activity state, exposing just three hooks, and one query used in the scheduler and timer tick. This is a prelude to making changes to the implementation of tracking when to perform an idle gc. - - - - - bd233355 by Duncan Coutts at 2026-09-16T06:52:02+01:00 Refactor the utils providing the I/O timeout for different system APIs We have to provide a timeout in three different time formats (int milliseconds, struct timeval *, and struct timespec *). These are for platform APIs including poll, select, ppoll, pselect, epoll_wait, epoll_wait2 and in future kevent and io_uring. Previously we had one util for each format that both worked out what the timeout should be and converted it into the particular format. This duplicates some logic and it also makes it awkward to modify the timeout value (since there's no common format). Modifying the timeout value is exactly what we want to do, in the next commit, where we want to adjust the timeout to take account of idle GC. - - - - - cd4aaf05 by Duncan Coutts at 2026-09-16T06:52:02+01:00 Add idle GC mode for !HAVE_PREEMPTION We have to do idle GC (and thus deadlock detection) differently when we do not have the ticker and the ability to interrupt the I/O manager when it's blocking. - - - - - 105 changed files: - .gitlab/ci.sh - + changelog.d/27732 - + changelog.d/T27629 - + changelog.d/T27788-js-selector - + changelog.d/fix-compacting-gc-constr-27649 - + changelog.d/fix-control0-mask-trampoline - + changelog.d/fix-threadlabel-segfault-27618 - + changelog.d/idle-gc-and-deadlock-detection - + changelog.d/select-io-manager - compiler/GHC/Core/Opt/Specialise.hs - compiler/GHC/Data/FastString.hs - compiler/GHC/Hs/Expr.hs - compiler/GHC/Hs/Pat.hs - compiler/GHC/Hs/Utils.hs - compiler/GHC/Parser.y - compiler/GHC/Parser/Annotation.hs - compiler/GHC/Parser/PostProcess.hs - compiler/GHC/Rename/Module.hs - compiler/GHC/StgToJS/Apply.hs - compiler/GHC/StgToJS/Symbols.hs - compiler/GHC/Tc/Errors/Types.hs - docs/users_guide/exts/type_data.rst - docs/users_guide/runtime_control.rst - libraries/base/src/GHC/RTS/Flags.hs - libraries/ghc-internal/src/GHC/Internal/RTS/Flags.hsc - rts/Capability.c - rts/ContinuationOps.cmm - rts/IOManager.c - rts/IOManager.h - rts/IOManagerInternals.h - + rts/IdleGC.c - + rts/IdleGC.h - rts/Linker.c - rts/PrimOps.cmm - rts/RaiseAsync.c - rts/RtsFlags.c - rts/RtsSignals.h - rts/RtsStartup.c - rts/RtsSymbols.c - rts/Schedule.c - rts/Schedule.h - rts/StgMiscClosures.cmm - rts/Timer.c - rts/configure.ac - rts/include/rts/Flags.h - rts/include/rts/storage/Closures.h - rts/include/stg/MiscClosures.h - rts/posix/Poll.c - rts/posix/Poll.h - rts/posix/Select.c - + rts/posix/SelectBis.c - + rts/posix/SelectBis.h - rts/posix/Signals.c - − rts/posix/Signals.h - rts/posix/Timeout.c - rts/posix/Timeout.h - rts/rts.cabal - rts/sm/Compact.c - rts/win32/AwaitEvent.c - rts/win32/ConsoleHandler.c - rts/win32/ConsoleHandler.h - testsuite/tests/codeGen/should_run/all.T - testsuite/tests/ghc-api/T25121_status.stdout - testsuite/tests/interface-stability/ghc-experimental-exports.stdout - testsuite/tests/interface-stability/ghc-experimental-exports.stdout-mingw32 - + testsuite/tests/javascript/T27788.hs - + testsuite/tests/javascript/T27788.stdout - testsuite/tests/javascript/all.T - testsuite/tests/parser/should_compile/DumpParsedAstComments.stderr - testsuite/tests/parser/should_compile/DumpSemis.stderr - testsuite/tests/printer/Test20297.stdout - testsuite/tests/profiling/should_run/Makefile - + testsuite/tests/rts/T26408.hs - + testsuite/tests/rts/T26408.stderr - + testsuite/tests/rts/T27618.hs - + testsuite/tests/rts/T27618.stdout - + testsuite/tests/rts/T27649.hs - + testsuite/tests/rts/T27649.stdout - testsuite/tests/rts/all.T - + testsuite/tests/rts/continuations/T27651.hs - + testsuite/tests/rts/continuations/T27651.stdout - testsuite/tests/rts/continuations/all.T - testsuite/tests/simplCore/should_compile/Makefile - + testsuite/tests/simplCore/should_compile/T27629.hs - + testsuite/tests/simplCore/should_compile/T27629.stderr - + testsuite/tests/simplCore/should_compile/T27629Plugin.hs - testsuite/tests/simplCore/should_compile/all.T - + 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/T27732e.hs - + testsuite/tests/type-data/should_fail/T27732e.stderr - + testsuite/tests/type-data/should_fail/T27732f.hs - + testsuite/tests/type-data/should_fail/T27732f.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 - utils/check-exact/ExactPrint.hs - utils/check-exact/Utils.hs - utils/jsffi/dyld.mjs The diff was not included because it is too large. View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/74c8aefcea73c1f18e6bfa530a783c… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/74c8aefcea73c1f18e6bfa530a783c… 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/apk/vpoc-bco-flattening
by Andreas Klebinger (＠AndreasK) 16 Sep '26

16 Sep '26

Andreas Klebinger pushed new branch wip/apk/vpoc-bco-flattening at Glasgow Haskell Compiler / GHC -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/tree/wip/apk/vpoc-bco-flattening 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/apk/o2-map
by Andreas Klebinger (＠AndreasK) 16 Sep '26

16 Sep '26

Andreas Klebinger pushed new branch wip/apk/o2-map at Glasgow Haskell Compiler / GHC -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/tree/wip/apk/o2-map 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/T27724] 14 commits: rts: handle large CONSTR closures in compacting GC
by Simon Peyton Jones (＠simonpj) 16 Sep '26

16 Sep '26

Simon Peyton Jones pushed to branch wip/T27724 at Glasgow Haskell Compiler / GHC Commits: 749d2448 by Luite Stegeman at 2026-09-15T14:07:01-04:00 rts: handle large CONSTR closures in compacting GC The function update_fwd_large in the compacting GC could run into an unexpected object with the following error: internal error: update_fwd_large: unknown/strange object 1 Closure type 1 is CONSTR. This patch adds cases for CONSTR and CONSTR_NOCAF. This is the same problem as #27434 (large AP closures, fixed by cca0d58963), which missed this case. Fixes #27649 - - - - - 177d6155 by Luite Stegeman at 2026-09-15T14:07:02-04:00 testsuite: fix T27434 test with compacting GC Ensure that the interpreter is actually run with the compacting GC - - - - - 5796aa63 by Luite Stegeman at 2026-09-15T14:07:49-04:00 rts: initialise the stack frame header for mask_frame and apply_mask_frame We must leave the stack in consistent state before jumping to mask_frame or apply_mask_frame because they may result. Failing to do so could lead to a crash if there were waiting exceptions. Fixes #27651 - - - - - 2486cc92 by Simon Peyton Jones at 2026-09-15T14:08:36-04:00 Re-introduce the "weird SpecDict" case In this commit commit f80375dd4945350a1d784e436975b48b9c736eaf Author: Simon Peyton Jones <simon.peytonjones(a)gmail.com> Date: Sun Jun 29 15:26:58 2025 +0100 Refactor of Specialise.hs I removed a test for a dictionary with unbound type variables. This turned out to be wrong; see #27629. So this MR re-introduces it. - - - - - 8e09a46f by Duncan Coutts at 2026-09-15T20:11:35-04:00 Refactor (and rename) removeFromQueues, to simplify I/O managers Rename it to unblockAndAppendToRunQueue which better reflects what it is intended to do. The post-condition for unblockAndAppendToRunQueue is that the TSO is on the run queue or it is in the process of migrating to another cap. Previously it achieved that by always directly adding the TSO to the run queue itself. But this actually made things more complicated for the I/O managers, because it meant they needed a separate code path for notifying for cancellation compared to notifying for completion. The general notification code would always add the TSO to the run queue itself. So the improvement is to allow different cases in unblockAndAppendToRunQueue to achieve the same outcome in different ways: either directly adding to the run queue or calling helper functions that do so themselves. This then allows the new I/O managers to share code between the sync and async cancellation, and to reuse their notifyIOCompletion helpers for cancellation. This avoids a source of bugs where the completion path may be updated but the cancellation path may be forgotten, or similarly in future for sync/async operations. Update all the existing in-RTS I/O managers, and the posix timeout code. - - - - - d668782c by Duncan Coutts at 2026-09-15T20:11:35-04:00 Document that awaitCompletedTimeoutsOrIO expects an empty run queue This was true before but implicit and not relied on much. It's better to be explicit, and allow things to depend on it. - - - - - 11d938bb by Duncan Coutts at 2026-09-15T20:11:35-04:00 Store the I/O opcode and fd in the StgAsyncIOOp This will be useful in several I/O managers and it is handy for logging and debugging. It also doesn't increase the size of the StgAsyncIOOp structure. There was enough spare padding space already. Update the poll I/O manager to set the new fields. Add a helper function to convert the enum IOReadOrWrite into the enum IOOpCode. Also change IOReadOrWrite to be an enum without a typedef, for consistency with other enumerations in IOManager.h - - - - - bfa87882 by Duncan Coutts at 2026-09-15T20:11:36-04:00 Add a new I/O manager based on select() Yes, this is the second such I/O manager, but it is a modern re-implementation based on the new in-RTS I/O manager infrastructure. So it is cleaner and faster than the old select I/O manager. Why do we need another I/O manager based on select? Why isn't the poll() one good enough as a baseline portable unix I/O manager? Because macOS. Apple Inc. is why we cannot have nice things. The man page for poll on macOS documents the fact that it does not work. At least, it does not work for all files. Specifically, it does not work for device files. Whereas macOS select() does work for device files. Aaaaarg! We _do_ want to deprecate and remove the old select I/O manager, but due to macOS we cannot do that until we have a replacement. This is that replacement. Until of course a nice new k-queue I/O manager arrives, which could become the new default for macOS and FreeBSD. Interestingly, this select I/O manager is actually faster than the poll one, on Linix, in some circumstances: specifically when many Haskell threads are waiting on the same fd. The poll I/O manager does O(n) work for n threads waiting on I/O, whereas the select one does O(fds) work for the number of fds that threads are waiting on. Usually this is 1:1, so it's not noticable, but one can concoct extreme benchmarks to show the difference. - - - - - 8e9de15a by Duncan Coutts at 2026-09-15T20:11:36-04:00 Minor updates in the poll I/O manager to keep in sync with select This keeps it in sync with select one. The changes are based on code review while implementing the new select I/O manager. The two I/O managers are so similar in structure that it makes sense to try to minimise the diff between them. This should aid understanding, and fixes to both in future. - - - - - 222668bb by Duncan Coutts at 2026-09-15T20:11:36-04:00 Document the new select I/O manager in the user guide in the RTS section about I/O managers. And add a changelog entry. - - - - - 0f48735b by Cheng Shao at 2026-09-15T20:12:23-04:00 Revert "wasm: workaround WebKit bug in dyld" This reverts commit c9b8465c2c338176fcab9d197e9d31f4aee11f68. The underlying webkit bug has been fixed in https://commits.webkit.org/314219@main. Closes #27564. - - - - - 809294f1 by Luite Stegeman at 2026-09-15T20:13:08-04:00 rts: make stg_threadLabelzh return a valid pointer for unlabeled threads. This fixes a segfault in the GC caused by stg_threadLabelzh returning a 0 pointer in a GC pointer field. stg_threadLabelzh returns a tuple of type (# Int#, ByteArray# #). If a thread has no label, the second field is unused. We must still return a valid heap object pointer. Instead of returning 0, we now return stg_DEAD_SLOT_closure. fixes #27618 - - - - - e2d57026 by Luite Stegeman at 2026-09-15T20:13:54-04:00 JS: fix selector thunk handling fix a bug where entering a selector thunk could lead to a crash if the selected field was still a thunk. fixes #27788 - - - - - c561949f by Simon Peyton Jones at 2026-09-16T13:25:34+01:00 Redesign the noinline magic Main idea: * When simplifying `noinline (f e1 e2)`, switch off inlining when simplifying `f` * Mechanism: see `simplOutId`, the `noinlineIdKey` case * If we see `noinline (f e1) e2`, the simplifier moves the `e2` inside; see the `splitContArgs` call. This is important so you can write `noinliine f e1 e2` and have it mean the same as `noinline (f e1 e2)`. * Now `f` sees all its arguments, henc: * Fixes #27724 * Fixes #23911 * Also fixes #27803 where we were not respecting `noinline` if the RHS was trivial See Note [noinlineId magic] for lots of specifics. It's surprisingly tricky! For some reason a couple of perf tests allocate 1.2% less at compile time,n namely T29872 and T8095. Geom mean decease of 0.1% Metric Decrease: T9872d - - - - - 82 changed files: - + changelog.d/T27629 - + changelog.d/T27724 - + changelog.d/T27788-js-selector - + changelog.d/fix-compacting-gc-constr-27649 - + changelog.d/fix-control0-mask-trampoline - + changelog.d/fix-threadlabel-segfault-27618 - + changelog.d/select-io-manager - compiler/GHC/Builtin/WiredIn/Ids.hs - compiler/GHC/Builtin/WiredIn/Prim.hs - compiler/GHC/Core/Opt/SetLevels.hs - compiler/GHC/Core/Opt/Simplify/Env.hs - compiler/GHC/Core/Opt/Simplify/Iteration.hs - compiler/GHC/Core/Opt/Simplify/Utils.hs - compiler/GHC/Core/Opt/Specialise.hs - compiler/GHC/Core/TyCo/Rep.hs - compiler/GHC/Core/Type.hs - compiler/GHC/CoreToIface.hs - compiler/GHC/CoreToStg/Prep.hs - compiler/GHC/Driver/Config/Core/Opt/Simplify.hs - compiler/GHC/HsToCore.hs - compiler/GHC/HsToCore/Expr.hs - compiler/GHC/StgToJS/Apply.hs - compiler/GHC/StgToJS/Symbols.hs - compiler/GHC/Tc/Instance/Class.hs - compiler/GHC/Tc/Types/Origin.hs - docs/users_guide/runtime_control.rst - libraries/base/src/GHC/RTS/Flags.hs - libraries/ghc-internal/src/GHC/Internal/Magic.hs - libraries/ghc-internal/src/GHC/Internal/RTS/Flags.hsc - rts/ContinuationOps.cmm - rts/IOManager.c - rts/IOManager.h - rts/IOManagerInternals.h - rts/PrimOps.cmm - rts/RaiseAsync.c - rts/StgMiscClosures.cmm - rts/configure.ac - rts/include/rts/Flags.h - rts/include/rts/storage/Closures.h - rts/include/stg/MiscClosures.h - rts/posix/Poll.c - rts/posix/Poll.h - + rts/posix/SelectBis.c - + rts/posix/SelectBis.h - rts/posix/Timeout.c - rts/posix/Timeout.h - rts/rts.cabal - rts/sm/Compact.c - testsuite/tests/corelint/LintEtaExpand.hs - + testsuite/tests/dmdanal/should_compile/T23911.hs - + testsuite/tests/dmdanal/should_compile/T23911.stderr - testsuite/tests/dmdanal/should_compile/all.T - testsuite/tests/interface-stability/base-exports.stdout - testsuite/tests/interface-stability/base-exports.stdout-mingw32 - testsuite/tests/interface-stability/ghc-experimental-exports.stdout - testsuite/tests/interface-stability/ghc-experimental-exports.stdout-mingw32 - testsuite/tests/interface-stability/ghc-prim-exports.stdout - testsuite/tests/interface-stability/ghc-prim-exports.stdout-mingw32 - + testsuite/tests/javascript/T27788.hs - + testsuite/tests/javascript/T27788.stdout - testsuite/tests/javascript/all.T - + testsuite/tests/rts/T27618.hs - + testsuite/tests/rts/T27618.stdout - + testsuite/tests/rts/T27649.hs - + testsuite/tests/rts/T27649.stdout - testsuite/tests/rts/all.T - + testsuite/tests/rts/continuations/T27651.hs - + testsuite/tests/rts/continuations/T27651.stdout - testsuite/tests/rts/continuations/all.T - testsuite/tests/simplCore/should_compile/Makefile - testsuite/tests/simplCore/should_compile/T18995.stderr - + testsuite/tests/simplCore/should_compile/T27629.hs - + testsuite/tests/simplCore/should_compile/T27629.stderr - + testsuite/tests/simplCore/should_compile/T27629Plugin.hs - + testsuite/tests/simplCore/should_compile/T27724a.hs - + testsuite/tests/simplCore/should_compile/T27724a.stderr - + testsuite/tests/simplCore/should_compile/T27803.hs - + testsuite/tests/simplCore/should_compile/T27803.stderr - testsuite/tests/simplCore/should_compile/all.T - testsuite/tests/typecheck/should_fail/T17940.stderr - utils/genprimopcode/Main.hs - utils/jsffi/dyld.mjs The diff was not included because it is too large. View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/dc55d4ce900445241c228693fe3bc1… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/dc55d4ce900445241c228693fe3bc1… 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/T26543b] 43 commits: X86 NCG: use btr/bts/btc for single-bit operations
by Simon Peyton Jones (＠simonpj) 16 Sep '26

16 Sep '26

Simon Peyton Jones pushed to branch wip/T26543b at Glasgow Haskell Compiler / GHC Commits: 2908ab36 by Simon Jakobi at 2026-09-05T07:22:17-04:00 X86 NCG: use btr/bts/btc for single-bit operations Previously the Cmm patterns x & ~(1 << i) x | (1 << i) x ^ (1 << i) compiled to mov/shl/not/and-style sequences of 3-4 instructions. Now they compile to a single btr, bts or btc, matching what C compilers produce. When the bit index is a literal, constant folding has already collapsed these patterns into ones with a literal mask, such as x & 0xfffffeffffffffff for x & ~(1 << 40). Such masks are now also compiled to a bit-test instruction when they don't fit in an imm32 and would otherwise have to be loaded into a register first. For a variable bit index, this applies only when the shift is unchecked (uncheckedShiftL#, Data.Bits.unsafeShiftL): the bounds-checked shiftL used by e.g. the default clearBit/setBit/complementBit implementations wraps the shift in a bounds mask that this optimisation does not see through. With a literal index, the bounds mask is constant-folded away, so the checked operations benefit too. See Note [Bit-test instructions] in GHC.CmmToAsm.X86.CodeGen. Fixes #25233. Assisted-by: Claude Fable 5 - - - - - c673ecf0 by Simon Peyton Jones at 2026-09-05T07:22:59-04:00 Move HsStatic free-var test to typechecker A `static` form should have no free *term* variables, but it can have free *type* variables. Alas, the renamer does not really know what is a term variable and what is a type variable, because of required type arguments. This patch moves the test to the typechecker, which does know. Addresses #27664 - - - - - 5939ceaf by sheaf at 2026-09-05T22:06:18-04:00 Windows: enforce path convention in ./configure As detailed in Note [MSYS paths] in Hadrian.Utilities, the standing convention (using Windows-style paths with forward slashes) is now enforced in ./configure instead of within Hadrian, removing the need for 'cygpath' calls within Hadrian. Fixes #26683 - - - - - a6061455 by sheaf at 2026-09-05T22:06:18-04:00 Hadrian: introduce ExeSpawnPath Specific details about the filepath used to specify the executable to spawn with CreateProcess matters on Windows: whether we use forward or backward slashes, a leading ./, or an absolute path changes how the executable is found. This commit introduces 'ExeSpawnPath' which is a path that is guaranteed to be found when spawning a process. All command invocations now go through this type to ensure the path has been properly sanitised. See Note [NeedCurrentDirectoryForExePath] in Hadrian.Utilities. The same treatment is applied to hsc2hs. Updates hsc2hs submodule. - - - - - e28313e3 by sheaf at 2026-09-05T22:07:06-04:00 Preserve tick ordering in 'tickTickedExpr' 'GHC.Core.Utils.tickTickedExpr' tries to combine a tick 't1' into an existing stack of ticks 't2s'. There are two situations: 1. 't1' is subsumed by a tick in 't2s': drop it. 2. A tick in 't2s' is subsumed by 't1', say 't2'. This commit ensures that in case (2) we keep 't1' on the outside instead of replacing 't2' at its position in the stack. This avoids re-ordering source notes (which was the cause of #27749). This fixes a regression introduced in 2dadf3b0d05. Fixes #27749 - - - - - 3172f557 by sheaf at 2026-09-05T22:07:06-04:00 Consistently prefer local source note ticks GHC.Cmm.DebugBlock.cmmDebugGen (DWARF annotations) and GHC.Stg.Debug.quickSourcePos (-finfo-table-map) both contained logic to prioritise source note ticks from the current module. This commit commons up this logic and propagates it to a third consumer: IPE stack frames, in GHC.Driver.GenerateCgIPEStub. See the new function GHC.Types.Tickish.bestSourceNote. - - - - - 192be0b6 by Luite Stegeman at 2026-09-07T19:43:36-04:00 rts: fix ctoi_tuple_spill_words getting out of sync Fix a few places that were not updating ctoi_tuple_spill_words correctly, leading to corruption/crashes when dealing with large unboxed tuples in bytecode: - captureContinuationAndAbort - findRetryFrameHelper/findAtomicallyFrameHelper - interpretBCO bci_BRK_FUN fixes #27633 - - - - - 604eb43c by Simon Jakobi at 2026-09-07T19:44:15-04:00 Hadrian: don't capture the testsuite driver's output (#27780) a6061455d54 switched the Testsuite RunTest case from Shake's cmd to the cmd' wrapper. cmd' always captures stdout and stderr, and since the caller asks for Exit, it returns without dumping what it captured. As a result the testsuite output no longer appears in CI job logs: failures, performance metrics and the summary were lost with the job. Use cmdExe, the uncaptured cmd, as the other plain-cmd sites in that commit do. Fixes #27780. Assisted-by: Claude Fable 5.1 - - - - - 06eee015 by Luite Stegeman at 2026-09-08T06:03:06+02:00 rts: Fix missing memory barrier in eval_thunk_selector (#27477) unchain_thunk_selectors() was missing an ACQUIRE_LOAD for the indirectee, leading to segfaults and corruption during GC on weakly-ordered architectures. Fixes #27477 - - - - - f8b2bd8f by Alan Zimmerman at 2026-09-08T09:39:12-04:00 EPA Fix HsCmdDo exact print with comments Exact printing of HsCmdDo was ignoring the location for the do statements, and this is an annotation that can have comments in it. Update it so we print the statements as a unit, including any comments. Also add the result of auditing that we capture comments in all needed places, noting that the remaining Anno SrcSpan instances are benign. - - - - - 430967ab by Duncan Coutts at 2026-09-09T11:07:01+01:00 Reorder cmm decls in HeapStackCheck for a better logical grouping And put more section headers in to deliniate the groups. We're about to add more here, so better to organise it first. - - - - - 344080fd by Duncan Coutts at 2026-09-09T11:07:01+01:00 Add raisePrimIOException and add it to RTS<->ghc-internal API The raisePrimIOException is a new helper function that I/O primops will use to help them report I/O errors. This is implemented in Haskell (since that's a lot easier), but has a calling convention that is easy(ish) to use from Cmm in the I/O primops. So we add it to the RTS API struct, and since we'll use it from Cmm we also need a field accessor macro for cmm (in deriveConstants). See the Note about how we cannot have nice things due to async exceptions and thunks preventing us from using catch. - - - - - cfdb3399 by Duncan Coutts at 2026-09-09T11:07:01+01:00 Add new blocking functions for I/O primops See the Note [Thread blocking for new I/O primops], and the Note [Calling convention for raisePrimIOException]. The point is, it will allow us to report synchronous exceptions from I/O primops, and do so much more flexibly. Previously the I/O managers could only report async exceptions and only nullary exceptions. This was OK historically, but no good as we add more I/O managers and expand the range of I/O operations we support. - - - - - f09c09d8 by Duncan Coutts at 2026-09-09T11:07:01+01:00 Change the encoding of results from the I/O manager to I/O primops Previously we just had async continue or heap overflow. We now extend what we can report with synchronous success, and synchronous failure with an errno. See Note [Encoding of result of I/O manager operations] We don't use these two new cases yet, but we will. In particular an epoll I/O manager needs to be able to report synchronous success or failure for waitRead#/waitWrite#. - - - - - 30f074d9 by Duncan Coutts at 2026-09-09T11:07:01+01:00 Switch waitRead/Write# to use new blocking return frames and update the I/O managers to set the result before resuming the blocked threads. This makes it possible for I/O managers to report synchronous exceptions from the I/O primops, but that will be done in a subsequent commit. - - - - - a8786ced by Duncan Coutts at 2026-09-09T11:07:01+01:00 Switch Poll and Select I/O managers to report sync exceptions rather than using raiseAsync with blockedOnBadFD_closure. This uses the new mechanism in the blocking frame return code to report synchronous exceptions. - - - - - 7a9df79a by Duncan Coutts at 2026-09-09T11:07:01+01:00 Remove now-unused blockedOnBadFD It was previously thrown by the select and poll I/O managers, but now they use raisePrimIOException (with an EBADF errno). - - - - - 6b0424e3 by Duncan Coutts at 2026-09-09T11:07:01+01:00 Improve the docs for delay# waitRead# and waitWrite# Document that the waitRead/Write# can throw exceptions (this was true before too), and that all of them are async exception cancellation points. - - - - - afeb2c30 by Duncan Coutts at 2026-09-09T20:08:58-04:00 Enable printf warnings for trace functions and fix resulting warnings Most of the existing printf-style functions are annotated with attributes to enable gcc/clang warnings for the printf format string, but several trace functions in Trace.h were missing this annotation. Enable them, and fix the resulting warnings. - - - - - 9a442c93 by Alan Zimmerman at 2026-09-09T20:09:36-04:00 EPA: Exact print ConDeclGADT without custom enterAnn !16321 brought in explicit capture of parens in a ConDeclGADT. The ExactPrint update introduced a modification of the fundamental function in exact printing, `enterAnn`, by splitting it into a version allowing injection of functionality normally handled by the ExactPrint class methods. This commit refactors that code, to restore the prior `enterAnn` version, by following the convention in ExactPrint of introducing a helper data structure with its own `ExactPrint` instance to achieve the same effect. - - - - - 4e9297ea by Simon Jakobi at 2026-09-11T08:32:45-04:00 ci: Actually pass --ignore-perf-failures to the testsuite driver 684c0018d9 changed the IGNORE_PERF_FAILURES handling to append to RUNTEST_ARGS with bash array syntax, but the three use sites still expand RUNTEST_ARGS as a scalar, which yields only the first array element. The appended flag was therefore dropped in every job, so perf improvements kept failing Marge Bot batches and master pipelines, contrary to #19562. Append as a string instead, matching the existing --force-colors append in test_hadrian. Fixes #27563. Assisted-by: Claude Fable 5.1 - - - - - 4f78dfdf by Simon Jakobi at 2026-09-11T08:33:24-04:00 testsuite: Give T26537 a 1.5x compile timeout Its -fregs-graph compile step tends to time out in unoptimized builds (#27188, #27776). Assisted-by: Claude Fable 5.1 - - - - - 130286e3 by Alan Zimmerman at 2026-09-11T08:34:08-04:00 EPA: Remove ListBanana / ListParens from AnnListBrackets This is a step towards making AnnList only represent lists of items which can have either braces or layout. - - - - - a9827d13 by Simon Jakobi at 2026-09-11T18:53:32-04:00 Reject ~, UNPACK and multiplicity annotations on type data fields Only `!` was rejected so far. `~`, UNPACK and multiplicity annotations were silently accepted. None of them make sense at the type level, so restriction (R3) of Note [Type data declarations] now covers all of them. Fixes #27732. Assisted-by: Claude Fable 5.1 - - - - - c71d5e23 by Alan Zimmerman at 2026-09-11T18:54:11-04:00 EPA: Add a Note for the exact print main loop - - - - - 7a108e43 by Simon Jakobi at 2026-09-12T18:35:59-04:00 FastString: Drop mkFastStringWith's constructor callback All three callers passed the same callback, a partial application of mkNewFastStringShortByteString to the string being interned. That partial application is allocated as a closure before the table lookup, on the common hit path too, although the callback is needed only after a miss. Drop the parameter and call mkNewFastStringShortByteString directly after a miss. Since nothing is passed "with" anymore, rename the function to internSB. Suggested by Simon PJ in #27528: https://gitlab.haskell.org/ghc/ghc/-/work_items/27528#note_687031 Assisted-by: Claude Fable 5 - - - - - 82c73b22 by Alan Zimmerman at 2026-09-12T18:36:38-04:00 EPA: More targeted HsDo exact print annotation HsDo is multi-purpose, as encoded in its HsDoFlavour field. Some of these are in a layout context (DoExpr, MDoExpr), others are not (ListComp, MonadComp). We are moving towards using AnnList only in layout contexts, so we switch the HsDo TTG annotation from holding an AnnList for this, to holding Either (EpToken "[", EpToken "]") AnnList This also allows us to trim down AnnListBrackets to only have braces or None, thereby opening the door for unification with the existing layout context data type EpLayout. - - - - - 749d2448 by Luite Stegeman at 2026-09-15T14:07:01-04:00 rts: handle large CONSTR closures in compacting GC The function update_fwd_large in the compacting GC could run into an unexpected object with the following error: internal error: update_fwd_large: unknown/strange object 1 Closure type 1 is CONSTR. This patch adds cases for CONSTR and CONSTR_NOCAF. This is the same problem as #27434 (large AP closures, fixed by cca0d58963), which missed this case. Fixes #27649 - - - - - 177d6155 by Luite Stegeman at 2026-09-15T14:07:02-04:00 testsuite: fix T27434 test with compacting GC Ensure that the interpreter is actually run with the compacting GC - - - - - 5796aa63 by Luite Stegeman at 2026-09-15T14:07:49-04:00 rts: initialise the stack frame header for mask_frame and apply_mask_frame We must leave the stack in consistent state before jumping to mask_frame or apply_mask_frame because they may result. Failing to do so could lead to a crash if there were waiting exceptions. Fixes #27651 - - - - - 2486cc92 by Simon Peyton Jones at 2026-09-15T14:08:36-04:00 Re-introduce the "weird SpecDict" case In this commit commit f80375dd4945350a1d784e436975b48b9c736eaf Author: Simon Peyton Jones <simon.peytonjones(a)gmail.com> Date: Sun Jun 29 15:26:58 2025 +0100 Refactor of Specialise.hs I removed a test for a dictionary with unbound type variables. This turned out to be wrong; see #27629. So this MR re-introduces it. - - - - - 8e09a46f by Duncan Coutts at 2026-09-15T20:11:35-04:00 Refactor (and rename) removeFromQueues, to simplify I/O managers Rename it to unblockAndAppendToRunQueue which better reflects what it is intended to do. The post-condition for unblockAndAppendToRunQueue is that the TSO is on the run queue or it is in the process of migrating to another cap. Previously it achieved that by always directly adding the TSO to the run queue itself. But this actually made things more complicated for the I/O managers, because it meant they needed a separate code path for notifying for cancellation compared to notifying for completion. The general notification code would always add the TSO to the run queue itself. So the improvement is to allow different cases in unblockAndAppendToRunQueue to achieve the same outcome in different ways: either directly adding to the run queue or calling helper functions that do so themselves. This then allows the new I/O managers to share code between the sync and async cancellation, and to reuse their notifyIOCompletion helpers for cancellation. This avoids a source of bugs where the completion path may be updated but the cancellation path may be forgotten, or similarly in future for sync/async operations. Update all the existing in-RTS I/O managers, and the posix timeout code. - - - - - d668782c by Duncan Coutts at 2026-09-15T20:11:35-04:00 Document that awaitCompletedTimeoutsOrIO expects an empty run queue This was true before but implicit and not relied on much. It's better to be explicit, and allow things to depend on it. - - - - - 11d938bb by Duncan Coutts at 2026-09-15T20:11:35-04:00 Store the I/O opcode and fd in the StgAsyncIOOp This will be useful in several I/O managers and it is handy for logging and debugging. It also doesn't increase the size of the StgAsyncIOOp structure. There was enough spare padding space already. Update the poll I/O manager to set the new fields. Add a helper function to convert the enum IOReadOrWrite into the enum IOOpCode. Also change IOReadOrWrite to be an enum without a typedef, for consistency with other enumerations in IOManager.h - - - - - bfa87882 by Duncan Coutts at 2026-09-15T20:11:36-04:00 Add a new I/O manager based on select() Yes, this is the second such I/O manager, but it is a modern re-implementation based on the new in-RTS I/O manager infrastructure. So it is cleaner and faster than the old select I/O manager. Why do we need another I/O manager based on select? Why isn't the poll() one good enough as a baseline portable unix I/O manager? Because macOS. Apple Inc. is why we cannot have nice things. The man page for poll on macOS documents the fact that it does not work. At least, it does not work for all files. Specifically, it does not work for device files. Whereas macOS select() does work for device files. Aaaaarg! We _do_ want to deprecate and remove the old select I/O manager, but due to macOS we cannot do that until we have a replacement. This is that replacement. Until of course a nice new k-queue I/O manager arrives, which could become the new default for macOS and FreeBSD. Interestingly, this select I/O manager is actually faster than the poll one, on Linix, in some circumstances: specifically when many Haskell threads are waiting on the same fd. The poll I/O manager does O(n) work for n threads waiting on I/O, whereas the select one does O(fds) work for the number of fds that threads are waiting on. Usually this is 1:1, so it's not noticable, but one can concoct extreme benchmarks to show the difference. - - - - - 8e9de15a by Duncan Coutts at 2026-09-15T20:11:36-04:00 Minor updates in the poll I/O manager to keep in sync with select This keeps it in sync with select one. The changes are based on code review while implementing the new select I/O manager. The two I/O managers are so similar in structure that it makes sense to try to minimise the diff between them. This should aid understanding, and fixes to both in future. - - - - - 222668bb by Duncan Coutts at 2026-09-15T20:11:36-04:00 Document the new select I/O manager in the user guide in the RTS section about I/O managers. And add a changelog entry. - - - - - 0f48735b by Cheng Shao at 2026-09-15T20:12:23-04:00 Revert "wasm: workaround WebKit bug in dyld" This reverts commit c9b8465c2c338176fcab9d197e9d31f4aee11f68. The underlying webkit bug has been fixed in https://commits.webkit.org/314219@main. Closes #27564. - - - - - 809294f1 by Luite Stegeman at 2026-09-15T20:13:08-04:00 rts: make stg_threadLabelzh return a valid pointer for unlabeled threads. This fixes a segfault in the GC caused by stg_threadLabelzh returning a 0 pointer in a GC pointer field. stg_threadLabelzh returns a tuple of type (# Int#, ByteArray# #). If a thread has no label, the second field is unused. We must still return a valid heap object pointer. Instead of returning 0, we now return stg_DEAD_SLOT_closure. fixes #27618 - - - - - e2d57026 by Luite Stegeman at 2026-09-15T20:13:54-04:00 JS: fix selector thunk handling fix a bug where entering a selector thunk could lead to a crash if the selected field was still a thunk. fixes #27788 - - - - - 6e5db94d by Simon Peyton Jones at 2026-09-16T13:18:59+01:00 Line up simpleUnifyCheck and check_ty_eq_rhs Even after #26543 was allegedly fixed, the original repo case in the Description continued to fail. The reason was that the QuickLook unifier, `qlUnify`, used `simpleUnifyCheck` for checking unification invariants; and `simpleUnifyCheck` conservatively rejected any RHS with a coercion hole in it. The upshot was that QuickLook was not as clever as it should be, wrongly failing to do an impredicative instantiation. Interestingly `check_ty_eq_rhs`, which does the same job, only during constraint solving, was more liberal: it just looked at the free vars of the coercion, and allowed coercion holes. This MR lines them up, adding some careful notes. See Note [simpleUnifyCheck] esp (SUC1) Note [Unification preconditions] esp (COERCIONS) Things are better than before, but I am still uncomfortable about the possibilty that a hole might be filled with a coercion that mentions the LHS type variable; for now I have left this discomfort documented in (SUC1). - - - - - b4305dae by Simon Peyton Jones at 2026-09-16T13:19:02+01:00 Improve the atvFolder stuff ...to use the same idiom that we already use in exprFreeVars. - - - - - fc7e1ef7 by Simon Peyton Jones at 2026-09-16T13:19:02+01:00 More free-var improvements - - - - - 187 changed files: - .gitlab/ci.sh - + changelog.d/27732 - + changelog.d/T26543 - + changelog.d/T27629 - + changelog.d/T27749 - + changelog.d/T27764 - + changelog.d/T27788-js-selector - + changelog.d/fix-compacting-gc-constr-27649 - + changelog.d/fix-control0-mask-trampoline - + changelog.d/fix-parallel-gc-selector-race-27477 - + changelog.d/fix-threadlabel-segfault-27618 - + changelog.d/ncg-x86-bit-test-instructions - + changelog.d/select-io-manager - compiler/GHC/Builtin/primops.txt.pp - compiler/GHC/Cmm/DebugBlock.hs - compiler/GHC/CmmToAsm/X86/CodeGen.hs - compiler/GHC/CmmToAsm/X86/Instr.hs - compiler/GHC/CmmToAsm/X86/Ppr.hs - compiler/GHC/Core/FVs.hs - compiler/GHC/Core/Opt/Specialise.hs - compiler/GHC/Core/TyCo/FVs.hs - compiler/GHC/Core/Utils.hs - compiler/GHC/Data/FastString.hs - compiler/GHC/Driver/GenerateCgIPEStub.hs - compiler/GHC/Driver/Main/Compile.hs - compiler/GHC/Hs/Doc.hs - compiler/GHC/Hs/Expr.hs - compiler/GHC/Hs/Extension/Pass.hs - compiler/GHC/Hs/Pat.hs - compiler/GHC/Hs/Utils.hs - compiler/GHC/Parser.y - compiler/GHC/Parser/Annotation.hs - compiler/GHC/Parser/PostProcess.hs - compiler/GHC/Rename/Expr.hs - compiler/GHC/Rename/Module.hs - compiler/GHC/Stg/Debug.hs - compiler/GHC/StgToJS/Apply.hs - compiler/GHC/StgToJS/Symbols.hs - compiler/GHC/Tc/Errors/Types.hs - compiler/GHC/Tc/Gen/App.hs - compiler/GHC/Tc/Gen/Expr.hs - compiler/GHC/Tc/Utils/Unify.hs - compiler/GHC/Types/Tickish.hs - compiler/GHC/Types/Var/FV.hs - configure.ac - docs/users_guide/exts/type_data.rst - docs/users_guide/runtime_control.rst - hadrian/src/Base.hs - hadrian/src/Builder.hs - hadrian/src/Hadrian/Builder.hs - hadrian/src/Hadrian/Builder/Ar.hs - hadrian/src/Hadrian/Oracles/Path.hs - hadrian/src/Hadrian/Utilities.hs - hadrian/src/Oracles/Setting.hs - hadrian/src/Oracles/TestSettings.hs - hadrian/src/Rules/BinaryDist.hs - hadrian/src/Rules/Changelog.hs - hadrian/src/Rules/Codes.hs - hadrian/src/Rules/Lint.hs - hadrian/src/Rules/Nofib.hs - hadrian/src/Rules/Test.hs - libraries/base/src/GHC/RTS/Flags.hs - libraries/ghc-internal/include/RtsIfaceSymbols.h - libraries/ghc-internal/src/GHC/Internal/Conc/IO.hs - libraries/ghc-internal/src/GHC/Internal/Event/Thread.hs - libraries/ghc-internal/src/GHC/Internal/RTS/Flags.hsc - m4/find_python.m4 - + m4/fp_canonicalise_win_path.m4 - m4/fp_find_nm.m4 - m4/fp_find_root.m4 - m4/fp_prog_ar.m4 - m4/fp_prog_ar_args.m4 - m4/fp_prog_sh.m4 - m4/fptools_alex.m4 - m4/fptools_happy.m4 - rts/Capability.c - rts/Continuation.c - rts/ContinuationOps.cmm - rts/HeapStackCheck.cmm - rts/IOManager.c - rts/IOManager.h - rts/IOManagerInternals.h - rts/Interpreter.c - rts/Messages.c - rts/Prelude.h - rts/PrimOps.cmm - rts/Printer.c - rts/RaiseAsync.c - rts/STM.c - rts/Schedule.c - rts/Sparks.c - rts/StableName.c - rts/StgMiscClosures.cmm - rts/ThreadPaused.c - rts/Threads.c - rts/Trace.h - rts/configure.ac - rts/include/rts/Flags.h - rts/include/rts/RtsToHsIface.h - rts/include/rts/storage/Closures.h - rts/include/stg/MiscClosures.h - rts/posix/Poll.c - rts/posix/Poll.h - rts/posix/Select.c - + rts/posix/SelectBis.c - + rts/posix/SelectBis.h - rts/posix/Timeout.c - rts/posix/Timeout.h - rts/rts.cabal - rts/sm/Compact.c - rts/sm/Evac.c - rts/sm/GC.c - rts/sm/GCUtils.c - rts/sm/MBlock.c - rts/sm/NonMoving.c - rts/sm/NonMovingMark.c - rts/sm/Storage.c - rts/sm/Sweep.c - + testsuite/tests/bytecode/T27633/Obj.hs - + testsuite/tests/bytecode/T27633/T27633a.hs - + testsuite/tests/bytecode/T27633/T27633a.stdout - + testsuite/tests/bytecode/T27633/T27633b.hs - + testsuite/tests/bytecode/T27633/T27633b.stdout - + testsuite/tests/bytecode/T27633/all.T - + testsuite/tests/codeGen/should_gen_asm/T25233.asm - + testsuite/tests/codeGen/should_gen_asm/T25233.hs - + testsuite/tests/codeGen/should_gen_asm/T25233b.asm - + testsuite/tests/codeGen/should_gen_asm/T25233b.cmm - testsuite/tests/codeGen/should_gen_asm/all.T - testsuite/tests/codeGen/should_run/all.T - testsuite/tests/ghc-api/T25121_status.stdout - + testsuite/tests/ghci.debugger/scripts/T27633c.hs - + testsuite/tests/ghci.debugger/scripts/T27633c.script - + testsuite/tests/ghci.debugger/scripts/T27633c.stdout - + testsuite/tests/ghci.debugger/scripts/T27633c_obj.hs - testsuite/tests/ghci.debugger/scripts/all.T - testsuite/tests/interface-stability/ghc-experimental-exports.stdout - testsuite/tests/interface-stability/ghc-experimental-exports.stdout-mingw32 - + testsuite/tests/javascript/T27788.hs - + testsuite/tests/javascript/T27788.stdout - testsuite/tests/javascript/all.T - testsuite/tests/parser/should_compile/DumpParsedAstComments.stderr - testsuite/tests/parser/should_compile/DumpSemis.stderr - testsuite/tests/printer/Test20297.stdout - testsuite/tests/rename/should_fail/RnStaticPointersFail01.stderr - testsuite/tests/rename/should_fail/RnStaticPointersFail03.stderr - testsuite/tests/rename/should_fail/T26545.stderr - + testsuite/tests/rts/T27477.hs - + testsuite/tests/rts/T27477.stdout - + testsuite/tests/rts/T27618.hs - + testsuite/tests/rts/T27618.stdout - + testsuite/tests/rts/T27649.hs - + testsuite/tests/rts/T27649.stdout - testsuite/tests/rts/all.T - + testsuite/tests/rts/continuations/T27651.hs - + testsuite/tests/rts/continuations/T27651.stdout - testsuite/tests/rts/continuations/all.T - testsuite/tests/simplCore/should_compile/Makefile - + testsuite/tests/simplCore/should_compile/T27629.hs - + testsuite/tests/simplCore/should_compile/T27629.stderr - + testsuite/tests/simplCore/should_compile/T27629Plugin.hs - + testsuite/tests/simplCore/should_compile/T27749.hs - + testsuite/tests/simplCore/should_compile/T27749.stderr - testsuite/tests/simplCore/should_compile/all.T - + 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/T27732e.hs - + testsuite/tests/type-data/should_fail/T27732e.stderr - + testsuite/tests/type-data/should_fail/T27732f.hs - + testsuite/tests/type-data/should_fail/T27732f.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 - + testsuite/tests/typecheck/should_compile/T26543_orig.hs - + testsuite/tests/typecheck/should_compile/T27664.hs - testsuite/tests/typecheck/should_compile/all.T - utils/check-exact/ExactPrint.hs - utils/check-exact/Utils.hs - utils/deriveConstants/Main.hs - utils/hsc2hs - utils/jsffi/dyld.mjs The diff was not included because it is too large. View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/e2f4f707b4ea34b99a04a761161856… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/e2f4f707b4ea34b99a04a761161856… 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/fendor/has-field-hie] 3 commits: Record `FieldLabel` source span in AST node
by Hannes Siebenhandl (＠fendor) 16 Sep '26

16 Sep '26

Hannes Siebenhandl pushed to branch wip/fendor/has-field-hie at Glasgow Haskell Compiler / GHC Commits: caf1171c by fendor at 2026-09-16T13:16:10+02:00 Record `FieldLabel` source span in AST node We attach evidence variables based on the source span of the concrete AST node in the HIE file. The evidence for the `HasField` constraint has the source span of the field selector, e.g. the AST node that gave rise to the `HasField` constraint. Since the AST node doesn't show up in the HIE file, the evidence for `HasField` was also not recorded for the span. Thus, `getEvidenceTree` wouldn't even list `HasField` as evidence, even in the perfectly normal case of: baz :: HasField "foo" f Int => f -> Int baz f = f.foo Requesting the evidence tree for `.foo` should point to the definition of `baz`, but since we omitted the source span for the field selector `.foo` from the AST node, the HIE file doesn't list it as evidence. By using the source spans of the individual field selectors, there are two consequences: * We can see the `HasField` evidence for record dot syntax at the field selector span * The reported type of `.foo` is `Foo -> Int` instead of just `Int` The latter is a change of behaviour that is unfortunate but the right behaviour, since there is now a source span for the whole expression `x.foo`, one for `x` and one for the selector `.foo`. If you query for the type at span `x.foo`, then the correct type `Int` is shown, but in downstream tooling (such as HLS), such requests are not possible in LSP. Thus, the behaviour changes. - - - - - cb9e4d0f by fendor at 2026-09-16T13:30:01+02:00 Allow any `Id` to be used for HIE evidence HIE evidence is used to show how a constraint has been solved and allows users to go directly to the definition or introduction of a particular evidence variable. So far, we only looked at evidence introduced by type class variables, but some evidence terms refer to other variables as well, such as record selectors. Such evidence terms add additional details and source locations. For generated evidence, such as `HasField` evidence to support `-XRecordDotSyntax`, the type class evidence is lacking and doesn't give us any usable source span pointing to the actual record selector. See this example evidence: $dHasField_aLw = GHC.Internal.Records.C:HasField @GHC.Internal.Types.Symbol @GHC.Internal.Types.LiftedRep @GHC.Internal.Types.LiftedRep @"foo" @Foo @Int (foo `cast` (<Foo -> Int>_R :: (Foo -> Int) ~R# (Foo -> Int))) The free variables of this term are `{C:HasField, foo}`. `foo` is the record selector from the type `Foo` and is crucial to guide users how this evidence is constructed, as the evidence `HasField` is not helpful. During HIE generation, we now take any `Id` into account to provide additional source spans to point to user to the definition site of the record selector. As a direct consequence, this allows HLS to implement a limited form of `Goto Definition` for expressions of the form `x.foo`, where `x :: Foo`. Capturing more `Id`s for evidence may have some side effects that are somewhat tricky to predict, since the tests are quite lacking. - - - - - 1793ebd8 by fendor at 2026-09-16T13:30:01+02:00 Add additional details to evidence bindings Evidence bindings can be all sorts of things, such as type class evidence, a record selector or other builtin constructs such as `Typeable`. - - - - - 12 changed files: - compiler/GHC/Iface/Ext/Ast.hs - compiler/GHC/Iface/Ext/Types.hs - compiler/GHC/Iface/Ext/Utils.hs - compiler/GHC/Rename/Expr.hs - + testsuite/tests/hiefile/should_run/HasFieldQueries.hs - + testsuite/tests/hiefile/should_run/HasFieldQueries.stdout - + testsuite/tests/hiefile/should_run/HieTypeable.hs - + testsuite/tests/hiefile/should_run/HieTypeable.stdout - testsuite/tests/hiefile/should_run/RecordDotTypes.hs - testsuite/tests/hiefile/should_run/RecordDotTypes.stdout - testsuite/tests/hiefile/should_run/T23492.stdout - testsuite/tests/hiefile/should_run/all.T Changes: ===================================== compiler/GHC/Iface/Ext/Ast.hs ===================================== @@ -23,7 +23,6 @@ import GHC.Core.DataCon ( dataConWrapperType ) import GHC.Core.Type ( Type, ForAllTyFlag(..) ) import GHC.Core.TyCon ( TyCon, tyConClass_maybe ) import GHC.Core.InstEnv -import GHC.Core.Predicate ( isEvId ) import GHC.Hs import GHC.Hs.Syn.Type @@ -33,7 +32,7 @@ import GHC.Types.Basic import GHC.Types.UnresolvedImport ( isGeneratedImport ) import GHC.Types.FieldLabel import GHC.Types.Avail ( Avails ) -import GHC.Types.Id ( isDataConId_maybe ) +import GHC.Types.Id ( isDataConId_maybe, isId, idDetails ) import GHC.Types.Name ( Name, nameSrcSpan, nameUnique, wiredInNameTyThing_maybe, getName ) import GHC.Types.Name.Env ( NameEnv, emptyNameEnv, extendNameEnv, lookupNameEnv ) import GHC.Types.Name.Reader ( RecFieldInfo(..), WithUserRdr(..) ) @@ -81,6 +80,7 @@ import Control.Applicative ( (<|>) ) import GHC.Types.TypeEnv ( TypeEnv ) import Control.Arrow ( second ) import Data.Traversable ( mapAccumR ) +import GHC.Types.Id.Info (IdDetails(..), recSelParentName) {- Note [Updating HieAst for changes in the GHC AST] ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -682,7 +682,7 @@ instance ToHie (Context (Located (WithUserRdr Name))) where hieEvIdsOfTerm :: EvTerm -> [EvId] -- Returns only EvIds satisfying relevantEvId -hieEvIdsOfTerm = runFVSelectiveList isEvId . evTermFVs +hieEvIdsOfTerm = runFVSelectiveList isId . evTermFVs instance ToHie (EvBindContext (LocatedA TcEvBinds)) where toHie (EvBindContext sc sp (L span (EvBinds bs))) @@ -690,7 +690,7 @@ instance ToHie (EvBindContext (LocatedA TcEvBinds)) where where go evbind = do let evDeps = hieEvIdsOfTerm $ eb_rhs evbind - depNames = EvBindDeps $ map varName evDeps + depNames = EvBindDeps $ map classifyEvDeps evDeps concatM $ [ toHie (C (EvidenceVarBind (EvLetBind depNames) (combineScopes sc (mkScope span)) sp) (L span $ eb_lhs evbind)) @@ -698,6 +698,12 @@ instance ToHie (EvBindContext (LocatedA TcEvBinds)) where ] toHie _ = pure [] +classifyEvDeps :: EvId -> EvBindDep +classifyEvDeps evId = + case idDetails evId of + RecSelId{sel_tycon} -> RecordField (varName evId) (recSelParentName sel_tycon) + _ -> EvidenceVar (varName evId) + instance ToHie (LocatedA HsWrapper) where toHie (L osp wrap) = case wrap of ===================================== compiler/GHC/Iface/Ext/Types.hs ===================================== @@ -598,17 +598,61 @@ instance Outputable EvVarSource where ppr (EvInstBind True cls) = text "bound due to a superclass of " <+> ppr cls ppr (EvLetBind deps) = text "bound by a let, depending on:" <+> ppr deps +data EvBindDep + = EvidenceVar Name + | RecordField Name Name + | TypeableEvidence Name + deriving (Eq, Ord) + +instance Outputable EvBindDep where + ppr = \ case + EvidenceVar n -> ppr n + RecordField sel parent -> ppr sel <+> text "of Record" <+> ppr parent + TypeableEvidence n -> ppr n <+> text "bound by Typeable" + +evBindDepName :: EvBindDep -> Name +evBindDepName = \ case + EvidenceVar n -> n + RecordField selector _record -> selector + TypeableEvidence n -> n + +evBindDepHieName :: EvBindDep -> HieName +evBindDepHieName = toHieName . evBindDepName + +instance Binary EvBindDep where + put_ bh = \ case + EvidenceVar n -> do + putByte bh 0 + put_ bh n + RecordField n sel -> do + putByte bh 1 + put_ bh n + put_ bh sel + TypeableEvidence n -> do + putByte bh 2 + put_ bh n + + get bh = + getByte bh >>= \ case + 0 -> EvidenceVar <$> get bh + 1 -> RecordField <$> get bh <*> get bh + 2 -> TypeableEvidence <$> get bh + t -> fail $ "EvBindDep: Unknown tag: " ++ show t + -- | Eq/Ord instances compare on the converted HieName, -- as non-exported names may have different uniques after -- a roundtrip -newtype EvBindDeps = EvBindDeps { getEvBindDeps :: [Name] } +newtype EvBindDeps = EvBindDeps { getEvBindDeps :: [EvBindDep] } deriving Outputable +evBindDepsNames :: EvBindDeps -> [Name] +evBindDepsNames = map evBindDepName . getEvBindDeps + instance Eq EvBindDeps where - (==) = coerce ((==) `on` map toHieName) + (==) = coerce ((==) `on` map evBindDepHieName) instance Ord EvBindDeps where - compare = coerce (compare `on` map toHieName) + compare = coerce (compare `on` map evBindDepHieName) instance Binary EvBindDeps where put_ bh (EvBindDeps xs) = put_ bh xs ===================================== compiler/GHC/Iface/Ext/Utils.hs ===================================== @@ -82,15 +82,19 @@ resolveVisibility kind ty_args foldType :: (HieType a -> a) -> HieTypeFix -> a foldType f (Roll t) = f $ fmap (foldType f) t -selectPoint :: HieFile -> (Int,Int) -> Maybe (HieAST Int) -selectPoint hf (sl,sc) = getFirst $ +selectPoint :: HieFile -> (Int,Int) -> Maybe (HieAST TypeIndex) +selectPoint hf p = selectRange hf p p + +selectRange :: HieFile -> (Int,Int) -> (Int,Int) -> Maybe (HieAST TypeIndex) +selectRange hf (sl,sc) (el, ec) = getFirst $ flip foldMap (M.toList (getAsts $ hie_asts hf)) $ \(HiePath fs,ast) -> First $ case selectSmallestContaining (sp fs) ast of Nothing -> Nothing Just ast' -> Just ast' where sloc fs = mkRealSrcLoc fs sl sc - sp fs = mkRealSrcSpan (sloc fs) (sloc fs) + eloc fs = mkRealSrcLoc fs el ec + sp fs = mkRealSrcSpan (sloc fs) (eloc fs) findEvidenceUse :: NodeIdentifiers a -> [Name] findEvidenceUse ni = [n | (Right n, dets) <- xs, any isEvidenceUse (identInfo dets)] @@ -141,7 +145,7 @@ getEvidenceTree refmap var = go emptyNameSet var det <- S.toList $ identInfo dets case det of EvidenceVarBind src@(EvLetBind (getEvBindDeps -> xs)) scp spn -> - pure $ Just ((src,scp,spn),mapMaybe (go $ extendNameSet seen var) xs) + pure $ Just ((src,scp,spn),mapMaybe (go (extendNameSet seen var) . evBindDepName) xs) EvidenceVarBind src scp spn -> pure $ Just ((src,scp,spn),[]) _ -> pure Nothing pure $ Tree.Node (EvidenceInfo var sp typ (Just evdet)) children @@ -386,7 +390,7 @@ definedInAsts asts n = case nameSrcSpan n of getEvidenceBindDeps :: ContextInfo -> [Name] getEvidenceBindDeps (EvidenceVarBind (EvLetBind xs) _ _) = - getEvBindDeps xs + evBindDepsNames xs getEvidenceBindDeps _ = [] isEvidenceBind :: ContextInfo -> Bool ===================================== compiler/GHC/Rename/Expr.hs ===================================== @@ -422,7 +422,7 @@ rnExpr (HsGetField _ e f) ; let f' = rnDotFieldOcc <$> f ; return ( mkExpandedExpr (HsGetField noExtField e f') - (mkGetField getField e (fmap (unLoc . dfoLabel) f')) + (mkGetField getField e (dfoLabel $ unLoc f')) , fv_e `plusFN` fv_getField ) } rnExpr (HsProjection _ fs) @@ -431,7 +431,7 @@ rnExpr (HsProjection _ fs) ; let fs' = NE.map rnDotFieldOcc fs ; return ( mkExpandedExpr (HsProjection noExtField fs') - (mkProjection getField circ $ NE.map (unLoc . dfoLabel) fs') + (mkProjection getField circ $ NE.map dfoLabel fs') , unitFN circ `plusFN` fv_getField) } ------------------------------------------ @@ -2882,8 +2882,9 @@ rnHsIf p b1 b2 -- mkGetField arg field calculates a get_field @field arg expression. -- e.g. z.x = mkGetField z x = get_field @x z -mkGetField :: Name -> LHsExpr GhcRn -> LocatedAn NoEpAnns FieldLabelString -> HsExpr GhcRn -mkGetField get_field arg field = unLoc (head $ mkGet get_field (arg :| []) field) +mkGetField :: Name -> LHsExpr GhcRn -> XRec GhcRn FieldLabelString -> HsExpr GhcRn +mkGetField get_field arg field = + HsApp noExtField (mkGetField' get_field field) arg -- mkSetField a field b calculates a set_field @field expression. -- e.g mkSetSetField a field b = set_field @"field" a b (read as "set field 'field' to a on b"). @@ -2902,14 +2903,16 @@ mkSet set_field acc (field, g) = wrapGenSpan (mkSetField set_field g field acc) -- mkProjection fields calculates a projection. -- e.g. .x = mkProjection [x] = getField @"x" -- .x.y = mkProjection [.x, .y] = (.y) . (.x) = getField @"y" . getField @"x" -mkProjection :: Name -> Name -> NonEmpty FieldLabelString -> HsExpr GhcRn -mkProjection getFieldName circName (field :| fields) = foldl' f (proj field) fields +mkProjection :: Name -> Name -> NonEmpty (XRec GhcRn FieldLabelString) -> HsExpr GhcRn +mkProjection getFieldName circName (field :| fields) = + unLoc $ foldl' f (mkGetField' getFieldName field) fields where - f :: HsExpr GhcRn -> FieldLabelString -> HsExpr GhcRn - f acc field = genHsApps circName $ map wrapGenSpan [proj field, acc] + f :: LHsExpr GhcRn -> XRec GhcRn FieldLabelString -> LHsExpr GhcRn + f acc field = wrapGenSpan $ genHsApps circName [mkGetField' getFieldName field, acc] - proj :: FieldLabelString -> HsExpr GhcRn - proj (FieldLabelString f) = genHsVar getFieldName `genAppType` genHsTyLit f +mkGetField' :: Name -> XRec GhcRn FieldLabelString -> LHsExpr GhcRn +mkGetField' getFieldName (L ann (FieldLabelString f)) = + wrapGenSpan' (getHasLoc ann) (genHsVar getFieldName `genAppType` genHsTyLit f) -- mkProjUpdateSetField calculates functions representing dot notation record updates. -- e.g. Suppose an update like foo.bar = 1. ===================================== testsuite/tests/hiefile/should_run/HasFieldQueries.hs ===================================== @@ -0,0 +1,52 @@ +{-# LANGUAGE OverloadedRecordDot #-} +module Main where + +import TestUtils +import GHC.Records +import GHC.TypeLits +import Data.Tree + +data Thing = Thing {field1 :: Char, field2 :: Bool} + deriving (Show, Eq) + +foo :: Thing -> String +foo t = show t.field1 +-- ^ this is the point + +testing2 (x :: Thing) = x.field1 +-- ^ this is the point +-- ^ this is the point + +data NestedThing = NestedThing { nested1 :: Thing } + +nestedSig :: NestedThing -> Char +nestedSig n = n.nested1.field1 +-- ^ this is the point +-- ^ this is the point + +nestedNoSig n = n.nested1.field2 :: Bool +-- ^ this is the point +-- ^ this is the point + + +withConstraint :: HasField "field1" x Char => x -> Char +withConstraint x = x.field1 +-- ^ this is the point + +points = + [ (13,17) + , (16,25) + , (16,27) + , (23,17) + , (23,25) + , (27,20) + , (27,28) + , (33,22) + ] + +main = do + (df, hf) <- readTestHie "HasFieldQueries.hie" + let refmap = generateReferencesMap $ getAsts $ hie_asts hf + + traverse (explainEv df hf refmap) points + return () ===================================== testsuite/tests/hiefile/should_run/HasFieldQueries.stdout ===================================== @@ -0,0 +1,156 @@ +========================== +At point (13,17), we found: +========================== +┌ +│ $dHasField at HasFieldQueries.hs:1:1, of type: HasField "field1" Thing Char +│ is an evidence variable bound by a let, depending on: [C:HasField, +│ field1 of Record Thing] +│ with scope: ModuleScope +│ +│ Defined at <no location info> +└ +| ++- ┌ +| │ C:HasField at HasFieldQueries.hs:1:1, of type: forall {k} (x :: k) r a. (r -> a) -> HasField x r a +| │ is a usage of an external evidence variable +| │ Defined in `GHC.Internal.Records' +| └ +| +`- ┌ + │ field1 at HasFieldQueries.hs:1:1, of type: Thing -> Char + │ is a usage of an external evidence variable + │ Defined at HasFieldQueries.hs:9:21 + └ + +========================== +At point (16,25), we found: +========================== +========================== +At point (16,27), we found: +========================== +┌ +│ $dHasField at HasFieldQueries.hs:16:1-32, of type: HasField "field1" Thing Char +│ is an evidence variable bound by a let, depending on: [C:HasField, +│ field1 of Record Thing] +│ with scope: LocalScope HasFieldQueries.hs:16:1-32 +│ bound at: HasFieldQueries.hs:16:1-32 +│ Defined at <no location info> +└ +| ++- ┌ +| │ C:HasField at HasFieldQueries.hs:1:1, of type: forall {k} (x :: k) r a. (r -> a) -> HasField x r a +| │ is a usage of an external evidence variable +| │ Defined in `GHC.Internal.Records' +| └ +| +`- ┌ + │ field1 at HasFieldQueries.hs:1:1, of type: Thing -> Char + │ is a usage of an external evidence variable + │ Defined at HasFieldQueries.hs:9:21 + └ + +========================== +At point (23,17), we found: +========================== +┌ +│ $dHasField at HasFieldQueries.hs:1:1, of type: HasField "nested1" NestedThing Thing +│ is an evidence variable bound by a let, depending on: [C:HasField, +│ nested1 of Record NestedThing] +│ with scope: ModuleScope +│ +│ Defined at <no location info> +└ +| ++- ┌ +| │ C:HasField at HasFieldQueries.hs:1:1, of type: forall {k} (x :: k) r a. (r -> a) -> HasField x r a +| │ is a usage of an external evidence variable +| │ Defined in `GHC.Internal.Records' +| └ +| +`- ┌ + │ nested1 at HasFieldQueries.hs:1:1, of type: NestedThing -> Thing + │ is a usage of an external evidence variable + │ Defined at HasFieldQueries.hs:20:34 + └ + +========================== +At point (23,25), we found: +========================== +┌ +│ $dHasField at HasFieldQueries.hs:1:1, of type: HasField "field1" Thing Char +│ is an evidence variable bound by a let, depending on: [C:HasField, +│ field1 of Record Thing] +│ with scope: ModuleScope +│ +│ Defined at <no location info> +└ +| ++- ┌ +| │ C:HasField at HasFieldQueries.hs:1:1, of type: forall {k} (x :: k) r a. (r -> a) -> HasField x r a +| │ is a usage of an external evidence variable +| │ Defined in `GHC.Internal.Records' +| └ +| +`- ┌ + │ field1 at HasFieldQueries.hs:1:1, of type: Thing -> Char + │ is a usage of an external evidence variable + │ Defined at HasFieldQueries.hs:9:21 + └ + +========================== +At point (27,20), we found: +========================== +┌ +│ $dHasField at HasFieldQueries.hs:27:1-40, of type: HasField "nested1" r r +│ is an evidence variable bound by a let, depending on: [$dHasField] +│ with scope: LocalScope HasFieldQueries.hs:27:1-40 +│ bound at: HasFieldQueries.hs:27:1-40 +│ Defined at <no location info> +└ +| +`- ┌ + │ $dHasField at HasFieldQueries.hs:27:1-40, of type: HasField "nested1" r r + │ is an evidence variable bound by a type signature + │ with scope: LocalScope HasFieldQueries.hs:27:1-40 + │ bound at: HasFieldQueries.hs:27:1-40 + │ Defined at <no location info> + └ + +========================== +At point (27,28), we found: +========================== +┌ +│ $dHasField at HasFieldQueries.hs:27:1-40, of type: HasField "field2" r Bool +│ is an evidence variable bound by a let, depending on: [$dHasField] +│ with scope: LocalScope HasFieldQueries.hs:27:1-40 +│ bound at: HasFieldQueries.hs:27:1-40 +│ Defined at <no location info> +└ +| +`- ┌ + │ $dHasField at HasFieldQueries.hs:27:1-40, of type: HasField "field2" r Bool + │ is an evidence variable bound by a type signature + │ with scope: LocalScope HasFieldQueries.hs:27:1-40 + │ bound at: HasFieldQueries.hs:27:1-40 + │ Defined at <no location info> + └ + +========================== +At point (33,22), we found: +========================== +┌ +│ $dHasField at HasFieldQueries.hs:33:1-27, of type: HasField "field1" x Char +│ is an evidence variable bound by a let, depending on: [$dHasField] +│ with scope: LocalScope HasFieldQueries.hs:33:1-27 +│ bound at: HasFieldQueries.hs:33:1-27 +│ Defined at <no location info> +└ +| +`- ┌ + │ $dHasField at HasFieldQueries.hs:33:1-27, of type: HasField "field1" x Char + │ is an evidence variable bound by a HsWrapper + │ with scope: LocalScope HasFieldQueries.hs:33:1-27 + │ bound at: HasFieldQueries.hs:33:1-27 + │ Defined at <no location info> + └ + ===================================== testsuite/tests/hiefile/should_run/HieTypeable.hs ===================================== @@ -0,0 +1,28 @@ +module Main where + +import Data.Dynamic +import Data.Typeable +import TestUtils + +data Thing = Thing {field1 :: Char, field2 :: Bool} + deriving (Show, Eq) + +castFromDynamic :: Dynamic -> Maybe Thing +castFromDynamic d = fromDynamic d + -- ^ this is the point + +rep :: Thing -> TypeRep +rep d = typeOf d + -- ^ this is the point + +points = + [ (11,21) + , (15,10) + ] + +main = do + (df, hf) <- readTestHie "HieTypeable.hie" + let refmap = generateReferencesMap $ getAsts $ hie_asts hf + + traverse (explainEv df hf refmap) points + return () ===================================== testsuite/tests/hiefile/should_run/HieTypeable.stdout ===================================== @@ -0,0 +1,30 @@ +========================== +At point (11,21), we found: +========================== +┌ +│ $dTypeable at HieTypeable.hs:1:1, of type: Typeable Thing +│ is an evidence variable bound by a let, depending on: [$dTypeable] +│ with scope: ModuleScope +│ +│ Defined at <no location info> +└ +| +`- ┌ + │ $dTypeable at HieTypeable.hs:1:1, of type: Typeable Thing + │ is an evidence variable bound by a let, depending on: [] + │ with scope: ModuleScope + │ + │ Defined at <no location info> + └ + +========================== +At point (15,10), we found: +========================== +┌ +│ $dTypeable at HieTypeable.hs:1:1, of type: Typeable Thing +│ is an evidence variable bound by a let, depending on: [] +│ with scope: ModuleScope +│ +│ Defined at <no location info> +└ + ===================================== testsuite/tests/hiefile/should_run/RecordDotTypes.hs ===================================== @@ -22,6 +22,11 @@ x = MyRecord { a = "Hello", b = 12, c = MyChild { z = "there" } } y = x.a ++ show x.b ++ x.c.z -- ^ ^ ^ ^^ -- 1 2 3 45 +-- ^-^ ^-^ ^-^ +-- 6 7 8 +-- ^---^ +-- 9 + p1,p2,p3,p4 :: (Int,Int) p1 = (22,6) @@ -30,10 +35,19 @@ p3 = (22,25) p4 = (22,28) p5 = (22,29) +r6 = (p1, (22, 8)) +r7 = ((22,17), p2) +r8 = (p3, (22, 27)) +r9 = (p3, p5) + selectPoint' :: HieFile -> (Int,Int) -> HieAST Int selectPoint' hf loc = maybe (error "point not found") id $ selectPoint hf loc +selectRange' :: HieFile -> ((Int,Int), (Int, Int)) -> HieAST Int +selectRange' hf (s, e) = + maybe (error "range not found") id $ selectRange hf s e + main = do (df, hf) <- readTestHie "RecordDotTypes.hie" forM_ [p1,p2,p3,p4,p5] $ \point -> do @@ -41,3 +55,11 @@ main = do let types = concatMap nodeType $ getSourcedNodeInfo $ sourcedNodeInfo $ selectPoint' hf point forM_ types $ \typ -> do putStrLn (renderHieType df $ recoverFullType typ (hie_types hf)) + + forM_ [r6, r7, r8, r9] $ \range -> do + putStr $ "At " ++ showRange range ++ ", got type: " + let types = concatMap nodeType $ getSourcedNodeInfo $ sourcedNodeInfo $ selectRange' hf range + forM_ types $ \typ -> do + putStrLn (renderHieType df $ recoverFullType typ (hie_types hf)) + where + showRange (p1, p2) = show p1 ++ " - " ++ show p2 ===================================== testsuite/tests/hiefile/should_run/RecordDotTypes.stdout ===================================== @@ -1,5 +1,9 @@ At (22,6), got type: MyRecord -At (22,20), got type: Integer +At (22,20), got type: MyRecord -> Integer At (22,25), got type: MyRecord -At (22,28), got type: String -At (22,29), got type: String \ No newline at end of file +At (22,28), got type: MyChild -> [Char] +At (22,29), got type: MyChild -> [Char] +At (22,6) - (22,8), got type: [Char] +At (22,17) - (22,20), got type: Integer +At (22,25) - (22,27), got type: MyChild +At (22,25) - (22,29), got type: [Char] ===================================== testsuite/tests/hiefile/should_run/T23492.stdout ===================================== @@ -4,4 +4,4 @@ PartialFieldSelector At (18,7), got type: PartialFieldSelector -> Bool At (23,7), got type: PartialFieldSelector At (23,8), got type: PartialFieldSelector -At (23,9), got type: Bool +At (23,9), got type: PartialFieldSelector -> Bool ===================================== testsuite/tests/hiefile/should_run/all.T ===================================== @@ -10,3 +10,4 @@ test('T23120', [extra_run_opts('"' + config.libdir + '"'), extra_files(['TestUti test('T24544', [extra_run_opts('"' + config.libdir + '"'), extra_files(['TestUtils.hs'])], compile_and_run, ['-package ghc -fwrite-ide-info']) test('HieGadtConSigs', [extra_run_opts('"' + config.libdir + '"'), extra_files(['TestUtils.hs'])], compile_and_run, ['-package ghc -fwrite-ide-info']) test('T25709', [extra_run_opts('"' + config.libdir + '"'), extra_files(['TestUtils.hs'])], compile_and_run, ['-package ghc -fwrite-ide-info']) +test('HasFieldQueries', [extra_run_opts('"' + config.libdir + '"'), extra_files(['TestUtils.hs'])], compile_and_run, ['-package ghc -fwrite-ide-info']) View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/8926227e75bdaeaf3f2a649f2d1edf… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/8926227e75bdaeaf3f2a649f2d1edf… You're receiving this email because of your account on gitlab.haskell.org. 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[Git][ghc/ghc][wip/jeltsch/improve-closure-property-check] Replace `ShortText` by `UnitAbiHash`
by Wolfgang Jeltsch (＠jeltsch) 16 Sep '26

16 Sep '26

Wolfgang Jeltsch pushed to branch wip/jeltsch/improve-closure-property-check at Glasgow Haskell Compiler / GHC Commits: 32c0a8d0 by Wolfgang Jeltsch at 2026-09-16T14:22:40+03:00 Replace `ShortText` by `UnitAbiHash` - - - - - 1 changed file: - compiler/GHC/Driver/Downsweep.hs Changes: ===================================== compiler/GHC/Driver/Downsweep.hs ===================================== @@ -57,7 +57,6 @@ import Language.Haskell.Syntax.ImpExp import GHC.Types.UnresolvedImport import GHC.Data.FastString -import GHC.Data.ShortText ( ShortText ) import GHC.Data.Maybe ( expectJust ) import qualified GHC.Data.Maybe as M import GHC.Data.OsPath ( OsPath, unsafeEncodeUtf ) @@ -96,6 +95,7 @@ import GHC.Unit.Module.Graph import GHC.Unit.Module.Deps import qualified GHC.Unit.Home.Graph as HUG import GHC.Unit.Module.Stage +import GHC.Unit.External.Index (UnitAbiHash) import Data.Either ( partitionEithers, lefts ) import Data.Map (Map) @@ -979,7 +979,7 @@ checkHomeUnitsClosed unit_env collect :: [UnitState] -- ^ The 'UnitState's of the home units from which to traverse -- the dependency graph. - -> State (UniqMap UnitId (Set ShortText)) [(UnitId, UnitId)] + -> State (UniqMap UnitId (Set UnitAbiHash)) [(UnitId, UnitId)] -- ^ A stateful computation that collects offending dependencies -- that have not yet been found. It uses its state, which is an -- efficent representation of a set of 'GlobalUnitKey's, to @@ -999,7 +999,7 @@ checkHomeUnitsClosed unit_env -> [UnitId] -- ^ The 'UnitId's of the units from which to traverse the dependency -- graph. - -> State (UniqMap UnitId (Set ShortText)) [(UnitId, UnitId)] + -> State (UniqMap UnitId (Set UnitAbiHash)) [(UnitId, UnitId)] -- ^ A stateful computation that collects offending dependencies that -- have not yet been found. It uses its state, which is an efficent -- representation of a set of 'GlobalUnitKey's, to keep track of @@ -1022,7 +1022,7 @@ checkHomeUnitsClosed unit_env unit_not_found_msg = "Unit not found during closure property check" -- | The ABI hash of the current unit. - unit_abi_hash :: ShortText + unit_abi_hash :: UnitAbiHash unit_abi_hash = unitAbiHash unit_info has_been_processed <- gets $ maybe False (Set.member unit_abi_hash) . View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/32c0a8d0c1a4d90e6c1444c6d31d10f… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/32c0a8d0c1a4d90e6c1444c6d31d10f… 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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