[Git][ghc/ghc][wip/ubxsumtag] 59 commits: level imports: Fix infinite loop with cyclic module imports

Luite Stegeman pushed to branch wip/ubxsumtag at Glasgow Haskell Compiler / GHC Commits: 8b731e3c by Matthew Pickering at 2025-07-21T13:36:43-04:00 level imports: Fix infinite loop with cyclic module imports I didn't anticipate that downsweep would run before we checked for cyclic imports. Therefore we need to use the reachability function which handles cyclic graphs. Fixes #26087 - - - - - d751a9f1 by Pierre Thierry at 2025-07-21T13:37:28-04:00 Fix documentation about deriving from generics - - - - - f8d9d016 by Andrew Lelechenko at 2025-07-22T21:13:28-04:00 Fix issues with toRational for types capable to represent infinite and not-a-number values This commit fixes all of the following pitfalls:

toRational (read "Infinity" :: Double) 179769313486231590772930519078902473361797697894230657273430081157732675805500963132708477322407536021120113879871393357658789768814416622492847430639474124377767893424865485276302219601246094119453082952085005768838150682342462881473913110540827237163350510684586298239947245938479716304835356329624224137216 % 1 toRational (read "NaN" :: Double) 269653970229347386159395778618353710042696546841345985910145121736599013708251444699062715983611304031680170819807090036488184653221624933739271145959211186566651840137298227914453329401869141179179624428127508653257226023513694322210869665811240855745025766026879447359920868907719574457253034494436336205824 % 1

realToFrac (read "NaN" :: Double) -- With -O0 Infinity realToFrac (read "NaN" :: Double) -- With -O1 NaN

realToFrac (read "NaN" :: Double) :: CDouble Infinity realToFrac (read "NaN" :: CDouble) :: Double Infinity

Implements https://github.com/haskell/core-libraries-committee/issues/338 - - - - - 5dabc718 by Zubin Duggal at 2025-07-22T21:14:10-04:00 haddock: Don't warn about missing link destinations for derived names. Fixes #26114 - - - - - 9c3a0937 by Matthew Pickering at 2025-07-22T21:14:52-04:00 template haskell: use a precise condition when implicitly lifting Implicit lifting corrects a level error by replacing references to `x` with `$(lift x)`, therefore you can use a level `n` binding at level `n + 1`, if it can be lifted. Therefore, we now have a precise check that the use level is 1 more than the bind level. Before this bug was not observable as you only had 0 and 1 contexts but it is easily evident when using explicit level imports. Fixes #26088 - - - - - 5144b22f by Andreas Klebinger at 2025-07-22T21:15:34-04:00 Add since tag and more docs for do-clever-arg-eta-expansion Fixes #26113 - - - - - c865623b by Andreas Klebinger at 2025-07-22T21:15:34-04:00 Add since tag for -fexpose-overloaded-unfoldings Fixes #26112 - - - - - 49a44ab7 by Simon Hengel at 2025-07-23T17:59:55+07:00 Refactor GHC.Driver.Errors.printMessages - - - - - 84711c39 by Simon Hengel at 2025-07-23T18:27:34+07:00 Respect `-fdiagnostics-as-json` for error messages from pre-processors (fixes #25480) - - - - - d046b5ab by Simon Hengel at 2025-07-24T06:12:05-04:00 Include the rendered message in -fdiagnostics-as-json output This implements #26173. - - - - - d2b89603 by Ben Gamari at 2025-07-24T06:12:47-04:00 rts/Interpreter: Factor out ctoi tuple info tables into data Instead of a massive case let's put this into data which we can reuse elsewhere. - - - - - 4bc78496 by Sebastian Graf at 2025-07-24T16:19:34-04:00 CprAnal: Detect recursive newtypes (#25944) While `cprTransformDataConWork` handles recursive data con workers, it did not detect the case when a newtype is responsible for the recursion. This is now detected in the `Cast` case of `cprAnal`. The same reproducer made it clear that `isRecDataCon` lacked congruent handling for `AppTy` and `CastTy`, now fixed. Furthermore, the new repro case T25944 triggered this bug via an infinite loop in `cprFix`, caused by the infelicity in `isRecDataCon`. While it should be much less likely to trigger such an infinite loop now that `isRecDataCon` has been fixed, I made sure to abort the loop after 10 iterations and emitting a warning instead. Fixes #25944. - - - - - 0a583689 by Sylvain Henry at 2025-07-24T16:20:26-04:00 STM: don't create a transaction in the rhs of catchRetry# (#26028) We don't need to create a transaction for the rhs of (catchRetry#) because contrary to the lhs we don't need to abort it on retry. Moreover it is particularly harmful if we have code such as (#26028): let cN = readTVar vN >> retry tree = c1 `orElse` (c2 `orElse` (c3 `orElse` ...)) atomically tree Because it will stack transactions for the rhss and the read-sets of all the transactions will be iteratively merged in O(n^2) after the execution of the most nested retry. - - - - - a49eca26 by Simon Peyton Jones at 2025-07-25T09:49:58+01:00 Renaming around predicate types .. we were (as it turned out) abstracting over type-class selectors in SPECIALISATION rules! Wibble isEqPred - - - - - f80375dd by Simon Peyton Jones at 2025-07-25T09:49:58+01:00 Refactor of Specialise.hs This patch just tidies up `specHeader` a bit, removing one of its many results, and adding some comments. No change in behaviour. Also add a few more `HasDebugCallStack` contexts. - - - - - 1bd12371 by Simon Peyton Jones at 2025-07-25T09:49:58+01:00 Improve treatment of SPECIALISE pragmas -- again! This MR does another major refactor of the way that SPECIALISE pragmas work, to fix #26115, #26116, #26117. * We now /always/ solve forall-constraints in an all-or-nothing way. See Note [Solving a Wanted forall-constraint] in GHC.Tc.Solver.Solve This means we might have unsolved quantified constraints, which need to be reported. See `inert_insts` in `getUnsolvedInerts`. * I refactored the short-cut solver for type classes to work by recursively calling the solver rather than by having a little baby solver that kept being not clever enough. See Note [Shortcut solving] in GHC.Tc.Solver.Dict * I totally rewrote the desugaring of SPECIALISE pragmas, again. The new story is in Note [Desugaring new-form SPECIALISE pragmas] in GHC.HsToCore.Binds Both old-form and new-form SPECIALISE pragmas now route through the same function `dsSpec_help`. The tricky function `decomposeRuleLhs` is now used only for user-written RULES, not for SPECIALISE pragmas. * I improved `solveOneFromTheOther` to account for rewriter sets. Previously it would solve a non-rewritten dict from a rewritten one. For equalities we were already dealing with this, in Some incidental refactoring * A small refactor: `ebv_tcvs` in `EvBindsBar` now has a list of coercions, rather than a set of tyvars. We just delay taking the free vars. * GHC.Core.FVs.exprFVs now returns /all/ free vars. Use `exprLocalFVs` for Local vars. Reason: I wanted another variant for /evidence/ variables. * Ues `EvId` in preference to `EvVar`. (Evidence variables are always Ids.) Rename `isEvVar` to `isEvId`. * I moved `inert_safehask` out of `InertCans` and into `InertSet` where it more properly belongs. Compiler-perf changes: * There was a palpable bug (#26117) which this MR fixes in newWantedEvVar, which bypassed all the subtle overlapping-Given and shortcutting logic. (See the new `newWantedEvVar`.) Fixing this but leads to extra dictionary bindings; they are optimised away quickly but they made CoOpt_Read allocate 3.6% more. * Hpapily T15164 improves. * The net compiler-allocation change is 0.0% Metric Decrease: T15164 Metric Increase: CoOpt_Read T12425 - - - - - 953fd8f1 by Simon Peyton Jones at 2025-07-25T09:49:58+01:00 Solve forall-constraints immediately, or not at all This MR refactors the constraint solver to solve forall-constraints immediately, rather than emitting an implication constraint to be solved later. The most immediate motivation was that when solving quantified constraints in SPECIALISE pragmas, we really really don't want to leave behind half- solved implications. Also it's in tune with the approach of the new short-cut solver, which recursively invokes the solver. It /also/ saves quite a bit of plumbing; e.g - The `wl_implics` field of `WorkList` is gone, - The types of `solveSimpleWanteds` and friends are simplified. - An EvFun contains binding, rather than an EvBindsVar ref-cell that will in the future contain bindings. That makes `evVarsOfTerm` simpler. Much nicer. It also improves error messages a bit. All described in Note [Solving a Wanted forall-constraint] in GHC.Tc.Solver.Solve. One tiresome point: in the tricky case of `inferConstraintsCoerceBased` we make a forall-constraint. This we /do/ want to partially solve, so we can infer a suitable context. (I'd be quite happy to force the user to write a context, bt I don't want to change behavior.) So we want to generate an /implication/ constraint in `emitPredSpecConstraints` rather than a /forall-constraint/ as we were doing before. Discussed in (WFA3) of the above Note. Incidental refactoring * `GHC.Tc.Deriv.Infer.inferConstraints` was consulting the state monad for the DerivEnv that the caller had just consulted. Nicer to pass it as an argument I think, so I have done that. No change in behaviour. - - - - - 6921ab42 by Simon Peyton Jones at 2025-07-25T09:49:58+01:00 Remove duplicated code in Ast.hs for evTermFreeVars This is just a tidy up. - - - - - 1165f587 by Simon Peyton Jones at 2025-07-25T09:49:58+01:00 Small tc-tracing changes only - - - - - 0776ffe0 by Simon Hengel at 2025-07-26T04:54:20-04:00 Respect `-fdiagnostics-as-json` for core diagnostics (see #24113) - - - - - cc1116e0 by Andrew Lelechenko at 2025-07-26T04:55:01-04:00 docs: add since pragma to Data.List.NonEmpty.mapMaybe - - - - - ee2dc248 by Simon Hengel at 2025-07-31T06:25:35-04:00 Update comments on `OptKind` to reflect the code reality - - - - - b029633a by Wen Kokke at 2025-07-31T06:26:21-04:00 rts: Disable --eventlog-flush-interval unless compiled with -threaded. This commit fixes issue #26222: Using --eventlog-flush-interval with the non-threaded RTS leads to eventlog corruption. https://gitlab.haskell.org/ghc/ghc/-/issues/26222 This commit makes three changes when code is compiled against the non-threaded RTS: 1. It disables the --eventlog-flush-interval flag. 2. It disables the documentation for the --eventlog-flush-interval flag. 3. It disables the relevant state from RtsConfig and code from Timer. 4. It updates the entry for --eventlog-flush-interval in the users guide. - - - - - 31159f1d by Wen Kokke at 2025-07-31T06:26:21-04:00 rts: Split T20006 into tests with and without -threaded - - - - - 618687ef by Simon Hengel at 2025-07-31T06:27:03-04:00 docs/users_guide/win32-dlls.rst: Remove references to `readline` - - - - - 083e40f1 by Rodrigo Mesquita at 2025-08-01T04:38:23-04:00 debugger: Uniquely identify breakpoints by internal id Since b85b11994e0130ff2401dd4bbdf52330e0bcf776 (support inlining breakpoints), a breakpoint has been identified at runtime by *two* pairs of . - The first, aka a 'BreakpointId', uniquely identifies a breakpoint in the source of a module by using the Tick index. A Tick index can index into ModBreaks.modBreaks_xxx to fetch source-level information about where that tick originated. - When a user specifies e.g. a line breakpoint using :break, we'll reverse engineer what a Tick index for that line - We update the `BreakArray` of that module (got from the LoaderState) at that tick index to `breakOn`. - A BCO we can stop at is headed by a BRK_FUN instruction. This instruction stores in an operand the `tick index` it is associated to. We look it up in the associated `BreakArray` (also an operand) and check wheter it was set to `breakOn`. - The second, aka the `ibi_info_mod` + `ibi_info_ix` of the `InternalBreakpointId`, uniquely index into the `imodBreaks_breakInfo` -- the information we gathered during code generation about the existing breakpoint *ocurrences*. - Note that with optimisation there may be many occurrences of the same source-tick-breakpoint across different modules. The `ibi_info_ix` is unique per occurrence, but the `bi_tick_ix` may be shared. See Note [Breakpoint identifiers] about this. - Note that besides the tick ids, info ids are also stored in `BRK_FUN` so the break handler can refer to the associated `CgBreakInfo`. In light of that, the driving changes come from the desire to have the info_id uniquely identify the breakpoint at runtime, and the source tick id being derived from it: - An InternalBreakpointId should uniquely identify a breakpoint just from the code-generation identifiers of `ibi_info_ix` and `ibi_info_mod`. So we drop `ibi_tick_mod` and `ibi_tick_ix`. - A BRK_FUN instruction need only record the "internal breakpoint id", not the tick-level id. So we drop the tick mod and tick index operands. - A BreakArray should be indexed by InternalBreakpointId rather than BreakpointId That means we need to do some more work when setting a breakpoint. Specifically, we need to figure out the internal ids (occurrences of a breakpoint) from the source-level BreakpointId we want to set the breakpoint at (recall :break refers to breaks at the source level). Besides this change being an improvement to the handling of breakpoints (it's clearer to have a single unique identifier than two competing ones), it unlocks the possibility of generating "internal" breakpoints during Cg (needed for #26042). It should also be easier to introduce multi-threaded-aware `BreakArrays` following this change (needed for #26064). Se also the new Note [ModBreaks vs InternalModBreaks] On i386-linux: ------------------------- Metric Decrease: interpreter_steplocal ------------------------- - - - - - bf03bbaa by Simon Hengel at 2025-08-01T04:39:05-04:00 Don't use MCDiagnostic for `ghcExit` This changes the error message of `ghcExit` from ``` <no location info>: error: Compilation had errors ``` to ``` Compilation had errors ``` - - - - - a889ec75 by Simon Hengel at 2025-08-01T04:39:05-04:00 Respect `-fdiagnostics-as-json` for driver diagnostics (see #24113) - - - - - 81577fe7 by Ben Gamari at 2025-08-02T04:29:39-04:00 configure: Allow override of CrossCompiling As noted in #26236, the current inference logic is a bit simplistic. In particular, there are many cases (e.g. building for a new libc) where the target and host triples may differ yet we are still able to run the produced artifacts as native code. Closes #26236. - - - - - 01136779 by Andreas Klebinger at 2025-08-02T04:30:20-04:00 rts: Support COFF BigObj files in archives. - - - - - 1f9e4f54 by Stephen Morgan at 2025-08-03T15:14:08+10:00 refactor: Modify Data.List.sortOn to use (>) instead of compare. (#26184) This lets a more efficient (>) operation be used if one exists. This is technically a breaking change for malformed Ord instances, where x > y is not equivalent to compare x y == GT. Discussed by the CLC in issue #332: https://github.com/haskell/core-libraries-committee/issues/332 - - - - - 4f6bc9cf by fendor at 2025-08-04T17:50:06-04:00 Revert "base: Expose Backtraces constructor and fields" This reverts commit 17db44c5b32fff82ea988fa4f1a233d1a27bdf57. - - - - - bcdec657 by Zubin Duggal at 2025-08-05T10:37:29+05:30 compiler: Export a version of `newNameCache` that is not prone to footguns. `newNameCache` must be initialized with both a non-"reserved" unique tag, as well as a list of known key names. Failing to do so results in hard to debug unique conflicts. It is difficult for API users to tell which unique tags are safe to use. So instead of leaving this up to the user to decide, we now export a version of `newNameCache` which uses a guaranteed non-reserved unique tag. In fact, this is now the way the unique tag is initialized for all invocations of the compiler. The original version of `newNameCache` is now exported as `newNameCache'` for advanced users. We also deprecate `initNameCache` as it is also prone to footguns and is completely subsumed in functionality by `newNameCache` and `newNameCache'`. Fixes #26135 and #26055 - - - - - 57d3b4a8 by Andrew Lelechenko at 2025-08-05T18:36:31-04:00 hadrian: bump Stackage snapshot to LTS 24.2 / GHC 9.10.2 In line with #25693 we should use GHC 9.10 as a boot compiler, while Hadrian stack.yaml was stuck on GHC 9.6. - - - - - c2a78cea by Peng Fan at 2025-08-05T18:37:27-04:00 NCG/LA64: implement atomic write with finer-grained DBAR hints Signed-off-by: Peng Fan - - - - - 95231c8e by Teo Camarasu at 2025-08-06T08:35:58-04:00 CODEOWNERS: add CLC as codeowner of base We also remove hvr, since I think he is no longer active - - - - - 77df0ded by Andrew Lelechenko at 2025-08-06T08:36:39-04:00 Bump submodule text to 2.1.3 - - - - - 8af260d0 by Nikolaos Chatzikonstantinou at 2025-08-06T08:37:23-04:00 docs: fix internal import in getopt examples This external-facing doc example shouldn't mention GHC internals when using 'fromMaybe'. - - - - - 69cc16ca by Marc Scholten at 2025-08-06T15:51:28-04:00 README: Add note on ghc.nix - - - - - 93a2f450 by Daniel Díaz at 2025-08-06T15:52:14-04:00 Link to the "Strict Bindings" docs from the linear types docs Strict Bidings are relevant for the kinds of multiplicity annotations linear lets support. - - - - - 246b7853 by Matthew Pickering at 2025-08-07T06:58:30-04:00 level imports: Check the level of exported identifiers The level imports specification states that exported identifiers have to be at level 0. This patch adds the requird level checks that all explicitly mentioned identifiers occur at level 0. For implicit export specifications (T(..) and module B), only level 0 identifiers are selected for re-export. ghc-proposal: https://github.com/ghc-proposals/ghc-proposals/pull/705 Fixes #26090 - - - - - 358bc4fc by fendor at 2025-08-07T06:59:12-04:00 Bump GHC on darwin CI to 9.10.1 - - - - - 1903ae35 by Matthew Pickering at 2025-08-07T12:21:10+01:00 ipe: Place strings and metadata into specific .ipe section By placing the .ipe metadata into a specific section it can be stripped from the final binary if desired. ``` objcopy --remove-section .ipe <binary> upx <binary> ``` Towards #21766 - - - - - c80dd91c by Matthew Pickering at 2025-08-07T12:22:42+01:00 ipe: Place magic word at the start of entries in the .ipe section The magic word "IPE\nIPE\n" is placed at the start of .ipe sections, then if the section is stripped, we can check whether the section starts with the magic word or not to determine whether there is metadata present or not. Towards #21766 - - - - - cab42666 by Matthew Pickering at 2025-08-07T12:22:42+01:00 ipe: Use stable IDs for IPE entries IPEs have historically been indexed and reported by their address. This makes it impossible to compare profiles between runs, since the addresses may change (due to ASLR) and also makes it tricky to separate out the IPE map from the binary. This small patch adds a stable identifier for each IPE entry. The stable identifier is a single 64 bit word. The high-bits are a per-module identifier and the low bits identify which entry in each module. 1. When a node is added into the IPE buffer it is assigned a unique identifier from an incrementing global counter. 2. Each entry already has an index by it's position in the `IpeBufferListNode`. The two are combined together by the `IPE_ENTRY_KEY` macro. Info table profiling uses the stable identifier rather than the address of the info table. The benefits of this change are: * Profiles from different runs can be easily compared * The metadata can be extracted from the binary (via the eventlog for example) and then stripped from the executable. Fixes #21766 - - - - - 2860a9a5 by Simon Peyton Jones at 2025-08-07T20:29:18-04:00 In TcSShortCut, typechecker plugins should get empty Givens Solving in TcShortCut mode means /ignoring the Givens/. So we should not pass them to typechecker plugins! Fixes #26258. This is a fixup to the earlier MR: commit 1bd12371feacc52394a0e660ef9349f9e8ee1c06 Author: Simon Peyton Jones Date: Mon Jul 21 10:04:49 2025 +0100 Improve treatment of SPECIALISE pragmas -- again! - - - - - 2157db2d by sterni at 2025-08-08T15:32:39-04:00 hadrian: enable terminfo if --with-curses-* flags are given The GHC make build system used to support WITH_TERMINFO in ghc.mk which allowed controlling whether to build GHC with terminfo or not. hadrian has replaced this with a system where this is effectively controlled by the cross-compiling setting (the default WITH_TERMINFO value was bassed on CrossCompiling, iirc). This behavior is undesireable in some cases and there is not really a good way to work around it. Especially for downstream packagers, modifying this via UserSettings is not really feasible since such a source file has to be kept in sync with Settings/Default.hs manually since it can't import Settings.Default or any predefined Flavour definitions. To avoid having to add a new setting to cfg/system.config and/or a new configure flag (though I'm happy to implement both if required), I've chosen to take --with-curses-* being set explicitly as an indication that the user wants to have terminfo enabled. This would work for Nixpkgs which sets these flags [1] as well as haskell.nix [2] (which goes to some extreme measures [3] [4] to force terminfo in all scenarios). In general, I'm an advocate for making the GHC build be the same for native and cross insofar it is possible since it makes packaging GHC and Haskell related things while still supporting cross much less compilicated. A more minimal GHC with reduced dependencies should probably be a specific flavor, not the default. Partially addresses #26288 by forcing terminfo to be built if the user explicitly passes configure flags related to it. However, it isn't built by default when cross-compiling yet nor is there an explicit way to control the package being built. [1]: https://github.com/NixOS/nixpkgs/blob/3a7266fcefcb9ce353df49ba3f292d06443760... [2]: https://github.com/input-output-hk/haskell.nix/blob/6eaafcdf04bab7be745d1aa4... [3]: https://github.com/input-output-hk/haskell.nix/blob/6eaafcdf04bab7be745d1aa4... [4]: https://github.com/input-output-hk/haskell.nix/blob/6eaafcdf04bab7be745d1aa4... - - - - - b3c31488 by David Feuer at 2025-08-08T15:33:21-04:00 Add default QuasiQuoters Add `defaultQuasiQuoter` and `namedDefaultQuasiQuoter` to make it easier to write `QuasiQuoters` that give helpful error messages when they're used in inappropriate contexts. Closes #24434. - - - - - 03555ed8 by Sylvain Henry at 2025-08-10T22:20:57-04:00 Handle non-fractional CmmFloats in Cmm's CBE (#26229) Since f8d9d016305be355f518c141f6c6d4826f2de9a2, toRational for Float and Double converts float's infinity and NaN into Rational's infinity and NaN (respectively 1%0 and 0%0). Cmm CommonBlockEliminator hashing function needs to take these values into account as they can appear as literals now. See added testcase. - - - - - 6c956af3 by J. Ryan Stinnett at 2025-08-10T22:21:42-04:00 Fix extensions list in `DoAndIfThenElse` docs - - - - - 6dc420b1 by J. Ryan Stinnett at 2025-08-10T22:21:42-04:00 Document status of `RelaxedPolyRec` extension This adds a brief extension page explaining the status of the `RelaxedPolyRec` extension. The behaviour of this mode is already explained elsewhere, so this page is mainly for completeness so that various lists of extensions have somewhere to point to for this flag. Fixes #18630 - - - - - 18036d52 by Simon Peyton Jones at 2025-08-11T11:31:20-04:00 Take more care in zonkEqTypes on AppTy/AppTy This patch fixes #26256. See Note [zonkEqTypes and the PKTI] in GHC.Tc.Solver.Equality - - - - - c8d76a29 by Zubin Duggal at 2025-08-11T11:32:02-04:00 ci: upgrade bootstrap compiler on windows to 9.10.1 - - - - - 34fc50c1 by Ben Gamari at 2025-08-11T13:36:25-04:00 Kill IOPort# This type is unnecessary, having been superceded by `MVar` and a rework of WinIO's blocking logic. See #20947. See https://github.com/haskell/core-libraries-committee/issues/213. - - - - - 56b32c5a by sheaf at 2025-08-12T10:00:19-04:00 Improve deep subsumption This commit improves the DeepSubsumption sub-typing implementation in GHC.Tc.Utils.Unify.tc_sub_type_deep by being less eager to fall back to unification. For example, we now are properly able to prove the subtyping relationship ((∀ a. a->a) -> Int) -> Bool <= β[tau] Bool for an unfilled metavariable β. In this case (with an AppTy on the right), we used to fall back to unification. No longer: now, given that the LHS is a FunTy and that the RHS is a deep rho type (does not need any instantiation), we try to make the RHS into a FunTy, viz. β := (->) γ We can then continue using covariance & contravariance of the function arrow, which allows us to prove the subtyping relationship, instead of trying to unify which would cause us to error out with: Couldn't match expected type ‘β’ with actual type ‘(->) ((∀ a. a -> a) -> Int) See Note [FunTy vs non-FunTy case in tc_sub_type_deep] in GHC.Tc.Utils.Unify. The other main improvement in this patch concerns type inference. The main subsumption logic happens (before & after this patch) in GHC.Tc.Gen.App.checkResultTy. However, before this patch, all of the DeepSubsumption logic only kicked in in 'check' mode, not in 'infer' mode. This patch adds deep instantiation in the 'infer' mode of checkResultTy when we are doing deep subsumption, which allows us to accept programs such as: f :: Int -> (forall a. a->a) g :: Int -> Bool -> Bool test1 b = case b of True -> f False -> g test2 b = case b of True -> g False -> f See Note [Deeply instantiate in checkResultTy when inferring]. Finally, we add representation-polymorphism checks to ensure that the lambda abstractions we introduce when doing subsumption obey the representation polymorphism invariants of Note [Representation polymorphism invariants] in GHC.Core. See Note [FunTy vs FunTy case in tc_sub_type_deep]. This is accompanied by a courtesy change to `(<.>) :: HsWrapper -> HsWrapper -> HsWrapper`, adding the equation: WpCast c1 <.> WpCast c2 = WpCast (c1 `mkTransCo` c2) This is useful because mkWpFun does not introduce an eta-expansion when both of the argument & result wrappers are casts; so this change allows us to avoid introducing lambda abstractions when casts suffice. Fixes #26225 - - - - - d175aff8 by Sylvain Henry at 2025-08-12T10:01:31-04:00 Add regression test for #18619 - - - - - a3983a26 by Sylvain Henry at 2025-08-12T10:02:20-04:00 RTS: remove some TSAN annotations (#20464) Use RELAXED_LOAD_ALWAYS macro instead. - - - - - 0434af81 by Ben Gamari at 2025-08-12T10:03:02-04:00 Bump time submodule to 1.15 Also required bumps of Cabal, directory, and hpc. - - - - - 0fd3f7b2 by Luite Stegeman at 2025-08-13T11:57:19+02:00 Use slots smaller than word as tag for smaller unboxed sums This packs unboxed sums more efficiently by allowing Word8, Word16 and Word32 for the tag field if the number of constructors is small enough - - - - - 291 changed files: - .gitlab/darwin/toolchain.nix - .gitlab/generate-ci/gen_ci.hs - .gitlab/jobs.yaml - CODEOWNERS - README.md - compiler/GHC/Builtin/Names.hs - compiler/GHC/Builtin/PrimOps/Ids.hs - compiler/GHC/Builtin/Types/Prim.hs - compiler/GHC/Builtin/primops.txt.pp - compiler/GHC/ByteCode/Asm.hs - compiler/GHC/ByteCode/Breakpoints.hs - compiler/GHC/ByteCode/Instr.hs - compiler/GHC/ByteCode/Linker.hs - compiler/GHC/ByteCode/Types.hs - compiler/GHC/Cmm.hs - compiler/GHC/Cmm/CommonBlockElim.hs - compiler/GHC/Cmm/Utils.hs - compiler/GHC/CmmToAsm/LA64/CodeGen.hs - compiler/GHC/CmmToAsm/PPC/Ppr.hs - compiler/GHC/CmmToAsm/Ppr.hs - compiler/GHC/CmmToLlvm/Data.hs - compiler/GHC/Core.hs - compiler/GHC/Core/FVs.hs - compiler/GHC/Core/Make.hs - compiler/GHC/Core/Opt/Arity.hs - compiler/GHC/Core/Opt/CprAnal.hs - compiler/GHC/Core/Opt/Monad.hs - compiler/GHC/Core/Opt/SpecConstr.hs - compiler/GHC/Core/Opt/Specialise.hs - compiler/GHC/Core/Opt/WorkWrap/Utils.hs - compiler/GHC/Core/Predicate.hs - compiler/GHC/Core/Rules.hs - compiler/GHC/Core/Subst.hs - compiler/GHC/Core/TyCo/Rep.hs - compiler/GHC/Core/Unfold/Make.hs - compiler/GHC/Core/Utils.hs - compiler/GHC/CoreToIface.hs - compiler/GHC/Driver/CmdLine.hs - compiler/GHC/Driver/Errors.hs - compiler/GHC/Driver/Main.hs - compiler/GHC/Driver/Make.hs - compiler/GHC/HsToCore.hs - compiler/GHC/HsToCore/Binds.hs - compiler/GHC/HsToCore/Breakpoints.hs - compiler/GHC/HsToCore/Errors/Ppr.hs - compiler/GHC/HsToCore/Pmc/Solver/Types.hs - compiler/GHC/Iface/Ext/Ast.hs - compiler/GHC/Linker/Loader.hs - compiler/GHC/Rename/Splice.hs - compiler/GHC/Runtime/Debugger/Breakpoints.hs - compiler/GHC/Runtime/Eval.hs - compiler/GHC/Runtime/Interpreter.hs - compiler/GHC/Stg/Unarise.hs - compiler/GHC/StgToByteCode.hs - compiler/GHC/StgToCmm/InfoTableProv.hs - compiler/GHC/StgToCmm/Prim.hs - compiler/GHC/StgToJS/Prim.hs - compiler/GHC/SysTools/Process.hs - compiler/GHC/SysTools/Tasks.hs - compiler/GHC/Tc/Deriv.hs - compiler/GHC/Tc/Deriv/Infer.hs - compiler/GHC/Tc/Deriv/Utils.hs - compiler/GHC/Tc/Errors.hs - compiler/GHC/Tc/Errors/Ppr.hs - compiler/GHC/Tc/Gen/App.hs - compiler/GHC/Tc/Gen/Export.hs - compiler/GHC/Tc/Gen/Expr.hs - compiler/GHC/Tc/Gen/HsType.hs - compiler/GHC/Tc/Gen/Pat.hs - compiler/GHC/Tc/Gen/Sig.hs - compiler/GHC/Tc/Solver.hs - compiler/GHC/Tc/Solver/Default.hs - compiler/GHC/Tc/Solver/Dict.hs - compiler/GHC/Tc/Solver/Equality.hs - compiler/GHC/Tc/Solver/InertSet.hs - compiler/GHC/Tc/Solver/Monad.hs - compiler/GHC/Tc/Solver/Rewrite.hs - compiler/GHC/Tc/Solver/Solve.hs - + compiler/GHC/Tc/Solver/Solve.hs-boot - compiler/GHC/Tc/Solver/Types.hs - compiler/GHC/Tc/TyCl/PatSyn.hs - compiler/GHC/Tc/Types/Constraint.hs - compiler/GHC/Tc/Types/Evidence.hs - compiler/GHC/Tc/Types/Origin.hs - compiler/GHC/Tc/Utils/Concrete.hs - compiler/GHC/Tc/Utils/Monad.hs - compiler/GHC/Tc/Utils/TcMType.hs - compiler/GHC/Tc/Utils/TcType.hs - compiler/GHC/Tc/Utils/Unify.hs - compiler/GHC/Tc/Validity.hs - compiler/GHC/Tc/Zonk/Type.hs - compiler/GHC/Types/Error.hs - compiler/GHC/Types/Id/Make.hs - compiler/GHC/Types/Name/Cache.hs - compiler/GHC/Types/Name/Reader.hs - compiler/GHC/Types/RepType.hs - compiler/GHC/Types/Var.hs - compiler/GHC/Unit/Module/Graph.hs - compiler/GHC/Utils/Error.hs - compiler/GHC/Utils/Logger.hs - compiler/ghc.cabal.in - configure.ac - docs/users_guide/9.14.1-notes.rst - docs/users_guide/conf.py - docs/users_guide/debug-info.rst - + docs/users_guide/diagnostics-as-json-schema-1_2.json - docs/users_guide/expected-undocumented-flags.txt - docs/users_guide/exts/doandifthenelse.rst - docs/users_guide/exts/linear_types.rst - + docs/users_guide/exts/relaxed_poly_rec.rst - docs/users_guide/exts/strict.rst - docs/users_guide/exts/types.rst - docs/users_guide/runtime_control.rst - docs/users_guide/using-optimisation.rst - docs/users_guide/using.rst - docs/users_guide/win32-dlls.rst - ghc/GHCi/UI.hs - ghc/GHCi/UI/Monad.hs - ghc/ghc-bin.cabal.in - hadrian/src/Settings/Default.hs - hadrian/src/Settings/Packages.hs - hadrian/stack.yaml - hadrian/stack.yaml.lock - libraries/Cabal - libraries/base/base.cabal.in - libraries/base/changelog.md - libraries/base/src/Control/Exception/Backtrace.hs - libraries/base/src/Data/List/NonEmpty.hs - libraries/base/src/GHC/Exts.hs - libraries/base/src/GHC/Generics.hs - − libraries/base/src/GHC/IOPort.hs - libraries/base/src/System/Console/GetOpt.hs - libraries/directory - libraries/ghc-heap/GHC/Exts/Heap/Closures.hs - libraries/ghc-internal/ghc-internal.cabal.in - libraries/ghc-internal/src/GHC/Internal/Data/OldList.hs - libraries/ghc-internal/src/GHC/Internal/Event/Windows.hsc - libraries/ghc-internal/src/GHC/Internal/Event/Windows/Thread.hs - libraries/ghc-internal/src/GHC/Internal/Exts.hs - libraries/ghc-internal/src/GHC/Internal/Float.hs - libraries/ghc-internal/src/GHC/Internal/IO/Buffer.hs - libraries/ghc-internal/src/GHC/Internal/IO/Windows/Handle.hsc - − libraries/ghc-internal/src/GHC/Internal/IOPort.hs - libraries/ghc-internal/src/GHC/Internal/Prim/PtrEq.hs - libraries/ghc-internal/src/GHC/Internal/Real.hs - libraries/ghc-internal/src/GHC/Internal/TH/Quote.hs - libraries/ghc-prim/changelog.md - libraries/ghci/GHCi/Debugger.hs - libraries/ghci/GHCi/Message.hs - libraries/ghci/GHCi/Run.hs - libraries/hpc - libraries/template-haskell/Language/Haskell/TH/Quote.hs - libraries/template-haskell/changelog.md - libraries/text - libraries/time - libraries/unix - rts/Disassembler.c - rts/Exception.cmm - rts/IPE.c - rts/Interpreter.c - rts/Prelude.h - rts/PrimOps.cmm - rts/ProfHeap.c - rts/RaiseAsync.c - rts/RtsFlags.c - rts/RtsSymbols.c - rts/STM.c - rts/Timer.c - rts/eventlog/EventLog.c - rts/external-symbols.list.in - rts/include/rts/Flags.h - rts/include/rts/IPE.h - rts/include/stg/MiscClosures.h - rts/include/stg/SMP.h - rts/linker/LoadArchive.c - rts/posix/ticker/Pthread.c - rts/posix/ticker/TimerFd.c - rts/win32/AsyncWinIO.c - rts/win32/libHSghc-internal.def - testsuite/tests/codeGen/should_compile/T25166.stdout → testsuite/tests/codeGen/should_compile/T25166.stdout-ws-32 - + testsuite/tests/codeGen/should_compile/T25166.stdout-ws-64 - testsuite/tests/corelint/LintEtaExpand.stderr - testsuite/tests/corelint/T21115b.stderr - + testsuite/tests/cpranal/sigs/T25944.hs - + testsuite/tests/cpranal/sigs/T25944.stderr - testsuite/tests/cpranal/sigs/all.T - testsuite/tests/deriving/should_compile/T20815.hs - testsuite/tests/deriving/should_fail/T12768.stderr - testsuite/tests/deriving/should_fail/T1496.stderr - testsuite/tests/deriving/should_fail/T5498.stderr - testsuite/tests/deriving/should_fail/T7148.stderr - testsuite/tests/deriving/should_fail/T7148a.stderr - testsuite/tests/driver/json.stderr - testsuite/tests/driver/json_warn.stderr - testsuite/tests/haddock/haddock_testsuite/Makefile - + testsuite/tests/haddock/haddock_testsuite/T26114.hs - + testsuite/tests/haddock/haddock_testsuite/T26114.stdout - testsuite/tests/haddock/haddock_testsuite/all.T - testsuite/tests/hiefile/should_run/HieQueries.stdout - testsuite/tests/hiefile/should_run/TestUtils.hs - testsuite/tests/impredicative/T17332.stderr - testsuite/tests/indexed-types/should_fail/T5439.stderr - testsuite/tests/interface-stability/base-exports.stdout - testsuite/tests/interface-stability/base-exports.stdout-javascript-unknown-ghcjs - testsuite/tests/interface-stability/base-exports.stdout-mingw32 - testsuite/tests/interface-stability/base-exports.stdout-ws-32 - 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/interface-stability/template-haskell-exports.stdout - + testsuite/tests/lib/stm/T26028.hs - + testsuite/tests/lib/stm/T26028.stdout - + testsuite/tests/lib/stm/all.T - + testsuite/tests/numeric/should_compile/T26229.hs - testsuite/tests/numeric/should_compile/all.T - + testsuite/tests/numeric/should_run/T18619.hs - + testsuite/tests/numeric/should_run/T18619.stderr - testsuite/tests/numeric/should_run/T9810.stdout - testsuite/tests/numeric/should_run/all.T - testsuite/tests/partial-sigs/should_compile/T10403.stderr - + testsuite/tests/partial-sigs/should_compile/T26256.hs - + testsuite/tests/partial-sigs/should_compile/T26256.stderr - testsuite/tests/partial-sigs/should_compile/all.T - testsuite/tests/partial-sigs/should_fail/T10615.stderr - testsuite/tests/primops/should_run/UnliftedIOPort.hs - testsuite/tests/primops/should_run/all.T - testsuite/tests/quantified-constraints/T15290a.stderr - testsuite/tests/quantified-constraints/T19690.stderr - testsuite/tests/quantified-constraints/T19921.stderr - testsuite/tests/quantified-constraints/T21006.stderr - + testsuite/tests/rep-poly/NoEtaRequired.hs - testsuite/tests/rep-poly/T21906.stderr - testsuite/tests/rep-poly/all.T - testsuite/tests/roles/should_fail/RolesIArray.stderr - testsuite/tests/rts/flags/all.T - testsuite/tests/rts/ipe/ipeMap.c - testsuite/tests/rts/ipe/ipe_lib.c - + testsuite/tests/simplCore/should_compile/T26115.hs - + testsuite/tests/simplCore/should_compile/T26115.stderr - + testsuite/tests/simplCore/should_compile/T26116.hs - + testsuite/tests/simplCore/should_compile/T26116.stderr - + testsuite/tests/simplCore/should_compile/T26117.hs - + testsuite/tests/simplCore/should_compile/T26117.stderr - testsuite/tests/simplCore/should_compile/all.T - + testsuite/tests/splice-imports/DodgyLevelExport.hs - + testsuite/tests/splice-imports/DodgyLevelExport.stderr - + testsuite/tests/splice-imports/DodgyLevelExportA.hs - + testsuite/tests/splice-imports/LevelImportExports.hs - + testsuite/tests/splice-imports/LevelImportExports.stdout - + testsuite/tests/splice-imports/LevelImportExportsA.hs - testsuite/tests/splice-imports/Makefile - + testsuite/tests/splice-imports/ModuleExport.hs - + testsuite/tests/splice-imports/ModuleExport.stderr - + testsuite/tests/splice-imports/ModuleExportA.hs - + testsuite/tests/splice-imports/ModuleExportB.hs - + testsuite/tests/splice-imports/T26087.stderr - + testsuite/tests/splice-imports/T26087A.hs - + testsuite/tests/splice-imports/T26087B.hs - + testsuite/tests/splice-imports/T26088.stderr - + testsuite/tests/splice-imports/T26088A.hs - + testsuite/tests/splice-imports/T26088B.hs - + testsuite/tests/splice-imports/T26090.hs - + testsuite/tests/splice-imports/T26090.stderr - + testsuite/tests/splice-imports/T26090A.hs - testsuite/tests/splice-imports/all.T - testsuite/tests/typecheck/should_compile/T12427a.stderr - testsuite/tests/typecheck/should_compile/T23171.hs - + testsuite/tests/typecheck/should_compile/T26225.hs - + testsuite/tests/typecheck/should_compile/T26225b.hs - + testsuite/tests/typecheck/should_compile/T26256a.hs - testsuite/tests/typecheck/should_compile/TcSpecPragmas.stderr - testsuite/tests/typecheck/should_compile/all.T - − testsuite/tests/typecheck/should_fail/T12563.stderr - testsuite/tests/typecheck/should_fail/T14605.hs - testsuite/tests/typecheck/should_fail/T14605.stderr - testsuite/tests/typecheck/should_fail/T14618.stderr - testsuite/tests/typecheck/should_fail/T15801.stderr - testsuite/tests/typecheck/should_fail/T18640a.stderr - testsuite/tests/typecheck/should_fail/T18640b.stderr - testsuite/tests/typecheck/should_fail/T19627.stderr - testsuite/tests/typecheck/should_fail/T21530b.stderr - testsuite/tests/typecheck/should_fail/T22912.stderr - testsuite/tests/typecheck/should_fail/T6022.stderr - testsuite/tests/typecheck/should_fail/T8883.stderr - testsuite/tests/typecheck/should_fail/all.T - testsuite/tests/typecheck/should_fail/tcfail140.stderr - testsuite/tests/typecheck/should_fail/tcfail174.stderr - testsuite/tests/unboxedsums/unboxedsums_unit_tests.hs - utils/genprimopcode/Main.hs - utils/haddock/haddock-api/src/Haddock/Interface/Rename.hs The diff was not included because it is too large. View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/c8dfcce9b9ea223474aa6d1e0445c82... -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/c8dfcce9b9ea223474aa6d1e0445c82... You're receiving this email because of your account on gitlab.haskell.org.