Simon Peyton Jones pushed to branch wip/T25992a at Glasgow Haskell Compiler / GHC Commits: 62899117 by Florian Ragwitz at 2025-08-13T21:01:34-04:00 Extend record-selector usage ticking to all binds using a record field This extends the previous handling of ticking for RecordWildCards and NamedFieldPuns to all var bindings that involve record selectors. Note that certain patterns such as `Foo{foo = 42}` will currently not tick the `foo` selector, as ticking is triggered by `HsVar`s. Closes #26191. - - - - - b37b3af7 by Florian Ragwitz at 2025-08-13T21:01:34-04:00 Add release notes for 9.16.1 and move description of latest HPC changes there. - - - - - a5e4b7d9 by Ben Gamari at 2025-08-13T21:02:18-04:00 rts: Clarify rationale for undefined atomic wrappers Since c06e3f46d24ef69f3a3d794f5f604cb8c2a40cbc the RTS has declared various atomic operation wrappers defined by ghc-internal as undefined. While the rationale for this isn't clear from the commit message, I believe that this is necessary due to the unregisterised backend. Specifically, the code generator will reference these symbols when compiling RTS Cmm sources. - - - - - 50842f83 by Andreas Klebinger at 2025-08-13T21:03:01-04:00 Make unexpected LLVM versions a warning rather than an error. Typically a newer LLVM version *will* work so erroring out if a user uses a newer LLVM version is too aggressive. Fixes #25915 - - - - - c91e2650 by fendor at 2025-08-13T21:03:43-04:00 Store `StackTrace` and `StackSnapshot` in `Backtraces` Instead of decoding the stack traces when collecting the `Backtraces`, defer this decoding until actually showing the `Backtraces`. This allows users to customise how `Backtraces` are displayed by using a custom implementation of `displayExceptionWithInfo`, overwriting the default implementation for `Backtraces` (`displayBacktraces`). - - - - - dee28cdd by fendor at 2025-08-13T21:03:43-04:00 Allow users to customise the collection of exception annotations Add a global `CollectExceptionAnnotationMechanism` which determines how `ExceptionAnnotation`s are collected upon throwing an `Exception`. This API is exposed via `ghc-experimental`. By overriding how we collect `Backtraces`, we can control how the `Backtraces` are displayed to the user by newtyping `Backtraces` and giving a different instance for `ExceptionAnnotation`. A concrete use-case for this feature is allowing us to experiment with alternative stack decoders, without having to modify `base`, which take additional information from the stack frames. This commit does not modify how `Backtraces` are currently collected or displayed. - - - - - 66024722 by fendor at 2025-08-13T21:03:43-04:00 Expose Backtraces internals from ghc-experimental Additionally, expose the same API `base:Control.Exception.Backtrace` to make it easier to use as a drop-in replacement. - - - - - a766286f by Reed Mullanix at 2025-08-13T21:04:36-04:00 ghc-internal: Fix naturalAndNot for NB/NS case When the first argument to `naturalAndNot` is larger than a `Word` and the second is `Word`-sized, `naturalAndNot` will truncate the result: ```

...

...

naturalAndNot ((2 ^ 65) .|. (2 ^ 3)) (2 ^ 3) 0

In contrast, `naturalAndNot` does not truncate when both arguments are larger than a `Word`, so this appears to be a bug.
Luckily, the fix is pretty easy: we just need to call `bigNatAndNotWord#` instead of truncating.

Fixes #26230

- - - - -
3506fa7d by Simon Hengel at 2025-08-13T21:05:18-04:00
Report -pgms as a deprecated flag

(instead of reporting an unspecific warning)

Before:

    on the commandline: warning:
        Object splitting was removed in GHC 8.8

After:

    on the commandline: warning: [GHC-53692] [-Wdeprecated-flags]
        -pgms is deprecated: Object splitting was removed in GHC 8.8

- - - - -
51c701fe by Zubin Duggal at 2025-08-13T21:06:00-04:00
testsuite: Be more permissive when filtering out GNU_PROPERTY_TYPE linker warnings

The warning text is slightly different with ld.bfd.

Fixes #26249

- - - - -
dfe6f464 by Simon Hengel at 2025-08-13T21:06:43-04:00
Refactoring: Don't misuse `MCDiagnostic` for lint messages

`MCDiagnostic` is meant to be used for compiler diagnostics.

Any code that creates `MCDiagnostic` directly, without going through
`GHC.Driver.Errors.printMessage`, side steps `-fdiagnostics-as-json`
(see e.g. !14475, !14492 !14548).

To avoid this in the future I want to control more narrowly who creates
`MCDiagnostic` (see #24113).

Some parts of the compiler use `MCDiagnostic` purely for formatting
purposes, without creating any real compiler diagnostics.  This change
introduces a helper function, `formatDiagnostic`, that can be used in
such cases instead of constructing `MCDiagnostic`.

- - - - -
a8b2fbae by Teo Camarasu at 2025-08-13T21:07:24-04:00
rts: ensure MessageBlackHole.link is always a valid closure

We turn a MessageBlackHole into an StgInd in wakeBlockingQueue().
Therefore it's important that the link field, which becomes the
indirection field, always points to a valid closure.

It's unclear whether it's currently possible for the previous behaviour
to lead to a crash, but it's good to be consistent about this invariant nonetheless.

Co-authored-by: Andreas Klebinger <klebinger.andreas@gmx.at>

- - - - -
4021181e by Teo Camarasu at 2025-08-13T21:07:24-04:00
rts: spin if we see a WHITEHOLE in messageBlackHole

When a BLACKHOLE gets cancelled in raiseAsync, we indirect to a THUNK.
GC can then shortcut this, replacing our BLACKHOLE with a fresh THUNK.

This THUNK is not guaranteed to have a valid indirectee field.

If at the same time, a message intended for the previous BLACKHOLE is
processed and concurrently we BLACKHOLE the THUNK, thus temporarily
turning it into a WHITEHOLE, we can get a segfault, since we look at the
undefined indirectee field of the THUNK

The fix is simple: spin if we see a WHITEHOLE, and it will soon be
replaced with a valid BLACKHOLE.

Resolves #26205

- - - - -
1107af89 by Oleg Grenrus at 2025-08-13T21:08:06-04:00
Allow defining HasField instances for naughty fields

Resolves #26295

... as HasField solver doesn't solve for fields with "naughty"
selectors, we could as well allow defining HasField instances for these
fields.

- - - - -
020e7587 by Sylvain Henry at 2025-08-13T21:09:00-04:00
Fix Data.List unqualified import warning

- - - - -
fd811ded by Simon Peyton Jones at 2025-08-14T17:56:47-04:00
Make injecting implicit bindings into its own pass

Previously we were injecting "impliicit bindings" (data constructor
worker and wrappers etc)

  - both at the end of CoreTidy,
  - and at the start of CorePrep

This is unpleasant and confusing.  This patch puts it it its own pass,
addImplicitBinds, which runs between the two.

The function `GHC.CoreToStg.AddImplicitBinds.addImplicitBinds` now takes /all/
TyCons, not just the ones for algebraic data types.  That change ripples
through to
     - corePrepPgm
     - doCodeGen
     - byteCodeGen
All take [TyCon] which includes all TyCons

- - - - -
9bd7fcc5 by Simon Peyton Jones at 2025-08-14T17:56:47-04:00
Implement unary classes

The big change is described exhaustively in

   Note [Unary class magic] in GHC.Core.TyCon

Other changes

* We never unbox class dictionaries in worker/wrapper.  This has been true for some
  time now, but the logic is now centralised in functions in
  GHC.Core.Opt.WorkWrap.Utils, namely `canUnboxTyCon`, and `canUnboxArg`
  See Note [Do not unbox class dictionaries] in GHC.Core.Opt.WorkWrap.Utils.

* Refactored the `notWorthFloating` logic in GHc.Core.Opt.SetLevels.
  I can't remember if I actually changed any behaviour here, but if so it's
  only in a corner cases.

* Fixed a bug in `GHC.Core.TyCon.isEnumerationTyCon`, which was wrongly returning
  True for (##).

* Remove redundant Role argument to `liftCoSubstWithEx`.  It was always
  Representational.

* I refactored evidence generation in the constraint solver:
  * Made GHC.Tc.Types.Evidence contain better abstactions for evidence
    generation.
  * I deleted the file `GHC.Tc.Types.EvTerm` and merged its (small) contents
    elsewhere. It wasn't paying its way.
  * Made evidence for implicit parameters go via a proper abstraction.

* Fix inlineBoringOk; see (IB6) in Note [inlineBoringOk]
  This fixes a slowdown in `countdownEffectfulDynLocal`
  in the `effectful` library.

Smaller things

* Rename `isDataTyCon` to `isBoxedDataTyCon`.
* GHC.Core.Corecion.liftCoSubstWithEx was only called with Representational role,
  so I baked that into the function and removed the argument.
* Get rid of `GHC.Core.TyCon.tyConSingleAlgDataCon_maybe` in favour of calling
  `not isNewTyCon` at the call sites; more explicit.
* Refatored `GHC.Core.TyCon.isInjectiveTyCon`; but I don't think I changed its
  behaviour
* Moved `decomposeIPPred` to GHC.Core.Predicate

Compile time performance changes:
  geo. mean        +0.1%
    minimum        -6.8%
    maximum       +14.4%

The +14% one is in T21839c, where it seems that a bit more inlining
is taking place.  That seems acceptable; and the average change is small

Metric Decrease:
    LargeRecord
    T12227
    T12707
    T16577
    T21839r
    T5642
Metric Increase:
    T15164
    T21839c
    T3294
    T5321FD
    T5321Fun
    WWRec

- - - - -
b4075d71 by Simon Peyton Jones at 2025-08-14T17:56:47-04:00
Slight improvement to pre/postInlineUnconditionally

Avoids an extra simplifier iteration

- - - - -
9e443596 by Simon Peyton Jones at 2025-08-14T17:56:47-04:00
Fix a long-standing assertion error in normSplitTyConApp_maybe

- - - - -
91310ad0 by Simon Peyton Jones at 2025-08-14T17:56:47-04:00
Add comment to coercion optimiser

- - - - -
5b841d82 by Teo Camarasu at 2025-08-14T17:57:56-04:00
template-haskell: move some identifiers from ghc-internal to template-haskell

These identifiers are not used internally by the compiler. Therefore we
have no reason for them to be in ghc-internal.

By moving them to template-haskell, we benefit from it being easier to
change them and we avoid having to build them in stage0.

Resolves #26048

- - - - -
33e2c7e5 by Teo Camarasu at 2025-08-14T17:57:56-04:00
template-haskell: transfer $infix note to public module

This Haddock note should be in the public facing module

- - - - -
2a411fc4 by Sylvain Henry at 2025-08-14T17:59:09-04:00
JS: export HEAP8 symbol (#26290)

Newer Emscripten requires this.

- - - - -
248f78ca by Ben Gamari at 2025-08-14T17:59:51-04:00
users-guide: Drop the THREAD_RUNNABLE event

As of f361281c89fbce42865d8b8b27b0957205366186 it is no longer emitted.
- - - - -
706d33e3 by Recursion Ninja at 2025-08-15T04:12:12-04:00
Resolving issues #20645 and #26109

Correctly sign extending and casting smaller bit width types for LLVM operations:

  - bitReverse8#
  - bitReverse16#
  - bitReverse32#
  - byteSwap16#
  - byteSwap32#
  - pdep8#
  - pdep16#
  - pext8#
  - pext16#

- - - - -
1cdc6f46 by Cheng Shao at 2025-08-15T04:12:56-04:00
hadrian: enforce have_llvm=False for wasm32/js

This patch fixes hadrian to always pass have_llvm=False to the
testsuite driver for wasm32/js targets. These targets don't really
support the LLVM backend, and the optllvm test way doesn't work. We
used to special-case wasm32/js to avoid auto-adding optllvm way in
testsuite/config/ghc, but this is still problematic if someone writes
a new LLVM-related test and uses something like when(have_llvm(),
extra_ways(["optllvm"])). So better just enforce have_llvm=False for
these targets here.

- - - - -
b7beb8bb by Simon Peyton Jones at 2025-08-18T23:50:11+01:00
Take yet more care with reporting redundant constraints

This small patch fixes #25992, which relates to reporting redundant
constraints on default-method declarations.

See (TRC5) in Note [Tracking redundant constraints]

- - - - -


185 changed files:

- compiler/GHC/Builtin/Types.hs
- compiler/GHC/Builtin/primops.txt.pp
- compiler/GHC/ByteCode/InfoTable.hs
- compiler/GHC/CmmToLlvm/CodeGen.hs
- compiler/GHC/Core/Class.hs
- compiler/GHC/Core/Coercion.hs
- compiler/GHC/Core/Coercion/Opt.hs
- compiler/GHC/Core/DataCon.hs
- compiler/GHC/Core/FamInstEnv.hs
- compiler/GHC/Core/Lint.hs
- compiler/GHC/Core/Opt/Arity.hs
- compiler/GHC/Core/Opt/CprAnal.hs
- compiler/GHC/Core/Opt/DmdAnal.hs
- compiler/GHC/Core/Opt/OccurAnal.hs
- compiler/GHC/Core/Opt/SetLevels.hs
- compiler/GHC/Core/Opt/Simplify/Utils.hs
- compiler/GHC/Core/Opt/Specialise.hs
- compiler/GHC/Core/Opt/WorkWrap/Utils.hs
- compiler/GHC/Core/Predicate.hs
- compiler/GHC/Core/TyCo/Rep.hs
- compiler/GHC/Core/TyCon.hs
- compiler/GHC/Core/Type.hs
- compiler/GHC/Core/Unfold.hs
- compiler/GHC/Core/Unfold/Make.hs
- compiler/GHC/Core/Utils.hs
- compiler/GHC/CoreToStg.hs
- + compiler/GHC/CoreToStg/AddImplicitBinds.hs
- compiler/GHC/CoreToStg/Prep.hs
- compiler/GHC/Driver/Errors/Ppr.hs
- compiler/GHC/Driver/Main.hs
- compiler/GHC/Driver/Session.hs
- compiler/GHC/HsToCore/Binds.hs
- compiler/GHC/HsToCore/Expr.hs
- compiler/GHC/HsToCore/Foreign/Call.hs
- compiler/GHC/HsToCore/Ticks.hs
- compiler/GHC/Iface/Decl.hs
- compiler/GHC/Iface/Syntax.hs
- compiler/GHC/Iface/Tidy.hs
- compiler/GHC/IfaceToCore.hs
- compiler/GHC/Rename/Module.hs
- compiler/GHC/Runtime/Debugger/Breakpoints.hs
- compiler/GHC/Stg/Lint.hs
- compiler/GHC/StgToByteCode.hs
- compiler/GHC/StgToCmm.hs
- compiler/GHC/Tc/Errors.hs
- compiler/GHC/Tc/Gen/Bind.hs
- compiler/GHC/Tc/Gen/Expr.hs
- compiler/GHC/Tc/Instance/Class.hs
- compiler/GHC/Tc/Instance/Family.hs
- compiler/GHC/Tc/Solver/Default.hs
- compiler/GHC/Tc/Solver/Dict.hs
- compiler/GHC/Tc/Solver/Equality.hs
- compiler/GHC/Tc/Solver/Monad.hs
- compiler/GHC/Tc/Solver/Solve.hs
- compiler/GHC/Tc/TyCl.hs
- compiler/GHC/Tc/TyCl/Build.hs
- compiler/GHC/Tc/TyCl/Instance.hs
- compiler/GHC/Tc/TyCl/PatSyn.hs
- compiler/GHC/Tc/TyCl/Utils.hs
- − compiler/GHC/Tc/Types/EvTerm.hs
- compiler/GHC/Tc/Types/Evidence.hs
- compiler/GHC/Tc/Types/Origin.hs
- compiler/GHC/Tc/Utils/TcMType.hs
- compiler/GHC/Tc/Validity.hs
- compiler/GHC/Types/Demand.hs
- compiler/GHC/Types/Error.hs
- compiler/GHC/Types/Id.hs
- compiler/GHC/Types/Id/Make.hs
- compiler/GHC/Types/RepType.hs
- compiler/GHC/Types/TyThing.hs
- compiler/GHC/Utils/Error.hs
- compiler/ghc.cabal.in
- − docs/users_guide/9.14.1-notes.rst
- + docs/users_guide/9.16.1-notes.rst
- docs/users_guide/eventlog-formats.rst
- docs/users_guide/release-notes.rst
- hadrian/src/Settings/Builders/RunTest.hs
- libraries/base/changelog.md
- libraries/ghc-bignum/changelog.md
- + libraries/ghc-experimental/src/GHC/Exception/Backtrace/Experimental.hs
- libraries/ghc-internal/cbits/pdep.c
- libraries/ghc-internal/cbits/pext.c
- libraries/ghc-internal/src/GHC/Internal/Bignum/Natural.hs
- libraries/ghc-internal/src/GHC/Internal/Exception.hs
- libraries/ghc-internal/src/GHC/Internal/Exception/Backtrace.hs
- libraries/ghc-internal/src/GHC/Internal/Exception/Backtrace.hs-boot
- libraries/ghc-internal/src/GHC/Internal/TH/Lib.hs
- libraries/ghc-internal/src/GHC/Internal/TH/Lift.hs
- libraries/ghc-internal/src/GHC/Internal/TH/Syntax.hs
- + libraries/ghc-internal/tests/Makefile
- + libraries/ghc-internal/tests/all.T
- + libraries/ghc-internal/tests/backtraces/Makefile
- + libraries/ghc-internal/tests/backtraces/T14532a.hs
- + libraries/ghc-internal/tests/backtraces/T14532a.stdout
- + libraries/ghc-internal/tests/backtraces/T14532b.hs
- + libraries/ghc-internal/tests/backtraces/T14532b.stdout
- + libraries/ghc-internal/tests/backtraces/all.T
- libraries/template-haskell/Language/Haskell/TH/Lib.hs
- libraries/template-haskell/Language/Haskell/TH/Quote.hs
- libraries/template-haskell/Language/Haskell/TH/Syntax.hs
- libraries/template-haskell/tests/all.T
- rts/Messages.c
- rts/StgMiscClosures.cmm
- rts/Updates.h
- rts/external-symbols.list.in
- rts/js/mem.js
- rts/rts.cabal
- testsuite/config/ghc
- testsuite/driver/testlib.py
- testsuite/tests/arrows/should_compile/T21301.stderr
- testsuite/tests/core-to-stg/T24124.stderr
- testsuite/tests/deSugar/should_compile/T2431.stderr
- testsuite/tests/deSugar/should_fail/DsStrictFail.stderr
- testsuite/tests/deSugar/should_run/T20024.stderr
- testsuite/tests/deSugar/should_run/dsrun005.stderr
- testsuite/tests/deSugar/should_run/dsrun007.stderr
- testsuite/tests/deSugar/should_run/dsrun008.stderr
- testsuite/tests/deriving/should_run/T9576.stderr
- testsuite/tests/dmdanal/should_compile/T16029.stdout
- testsuite/tests/dmdanal/sigs/T21119.stderr
- testsuite/tests/dmdanal/sigs/T21888.stderr
- testsuite/tests/ghci.debugger/scripts/break011.stdout
- testsuite/tests/ghci.debugger/scripts/break024.stdout
- testsuite/tests/ghci/scripts/Defer02.stderr
- testsuite/tests/ghci/scripts/T15325.stderr
- testsuite/tests/hpc/recsel/recsel.hs
- testsuite/tests/hpc/recsel/recsel.stdout
- testsuite/tests/indexed-types/should_compile/T2238.hs
- testsuite/tests/interface-stability/template-haskell-exports.stdout
- + testsuite/tests/llvm/should_run/T20645.hs
- + testsuite/tests/llvm/should_run/T20645.stdout
- testsuite/tests/llvm/should_run/all.T
- testsuite/tests/numeric/should_compile/T15547.stderr
- testsuite/tests/numeric/should_compile/T23907.stderr
- + testsuite/tests/numeric/should_run/T26230.hs
- + testsuite/tests/numeric/should_run/T26230.stdout
- testsuite/tests/numeric/should_run/all.T
- testsuite/tests/numeric/should_run/foundation.hs
- + testsuite/tests/overloadedrecflds/should_run/T26295.hs
- + testsuite/tests/overloadedrecflds/should_run/T26295.stdout
- testsuite/tests/overloadedrecflds/should_run/all.T
- testsuite/tests/patsyn/should_run/ghci.stderr
- testsuite/tests/quasiquotation/T4491/test.T
- testsuite/tests/quotes/LiftErrMsgDefer.stderr
- testsuite/tests/roles/should_compile/Roles14.stderr
- testsuite/tests/roles/should_compile/Roles3.stderr
- testsuite/tests/roles/should_compile/Roles4.stderr
- testsuite/tests/safeHaskell/safeLanguage/SafeLang15.stderr
- testsuite/tests/simplCore/should_compile/DataToTagFamilyScrut.stderr
- testsuite/tests/simplCore/should_compile/T15205.stderr
- testsuite/tests/simplCore/should_compile/T17366.stderr
- testsuite/tests/simplCore/should_compile/T17966.stderr
- testsuite/tests/simplCore/should_compile/T22309.stderr
- testsuite/tests/simplCore/should_compile/T22375DataFamily.stderr
- testsuite/tests/simplCore/should_compile/T23307.stderr
- testsuite/tests/simplCore/should_compile/T23307a.stderr
- testsuite/tests/simplCore/should_compile/T25389.stderr
- testsuite/tests/simplCore/should_compile/T25713.stderr
- testsuite/tests/simplCore/should_compile/T7360.stderr
- testsuite/tests/simplStg/should_compile/T15226b.stderr
- testsuite/tests/tcplugins/CtIdPlugin.hs
- testsuite/tests/th/Makefile
- testsuite/tests/type-data/should_run/T22332a.stderr
- testsuite/tests/typecheck/should_compile/Makefile
- testsuite/tests/typecheck/should_compile/T12763.stderr
- testsuite/tests/typecheck/should_compile/T14774.stdout
- testsuite/tests/typecheck/should_compile/T18406b.stderr
- testsuite/tests/typecheck/should_compile/T18529.stderr
- + testsuite/tests/typecheck/should_compile/T25992a.hs
- testsuite/tests/typecheck/should_compile/all.T
- testsuite/tests/typecheck/should_run/T10284.stderr
- testsuite/tests/typecheck/should_run/T13838.stderr
- testsuite/tests/typecheck/should_run/T9497a-run.stderr
- testsuite/tests/typecheck/should_run/T9497b-run.stderr
- testsuite/tests/typecheck/should_run/T9497c-run.stderr
- testsuite/tests/unboxedsums/unpack_sums_7.stdout
- testsuite/tests/unsatisfiable/T23816.stderr
- testsuite/tests/unsatisfiable/UnsatDefer.stderr
- testsuite/tests/wasm/should_run/control-flow/LoadCmmGroup.hs
- testsuite/tests/wasm/should_run/control-flow/RunWasm.hs
- utils/genprimopcode/Lexer.x
- utils/genprimopcode/Main.hs
- utils/genprimopcode/Parser.y
- utils/genprimopcode/ParserM.hs
- utils/genprimopcode/Syntax.hs


The diff was not included because it is too large.


View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/c1ed1b1b1c7013d575fdbe70d6081ddf1289d19c...b7beb8bbd184e5d2e9813c55925b4d91bc0fabd3

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View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/c1ed1b1b1c7013d575fdbe70d6081ddf1289d19c...b7beb8bbd184e5d2e9813c55925b4d91bc0fabd3
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