Magnus pushed to branch wip/mangoiv/27672 at Glasgow Haskell Compiler / GHC

Commits:

• df058f1d
  by Simon Jakobi at 2026-09-02T07:18:06-04:00

  testsuite: Migrate perf tests off collect_compiler_stats('all')
  
  The 'all' metric argument applies a single tolerance to bytes
  allocated, max_bytes_used and peak_megabytes_allocated, although their
  noise profiles are incompatible (#27653): allocations are nearly
  deterministic, residency needs 10-20%, and peak is quantized to 1 MB.
  Any single tolerance is too tight for one metric or too slack for
  another. This migrates the remaining users of 'all' (and of the 'all'
  default) to explicit per-metric collection, ahead of removing 'all'
  from the driver.
  
  peak_megabytes_allocated is dropped everywhere: its 1 MB granularity
  makes tight relative windows meaningless (#27613), and it is sensitive
  to GC timing. In #27489 it drifted by -5.3% while max_bytes_used moved
  by less than 0.1%. Where a test guards a memory property,
  max_bytes_used covers it at byte granularity.
  
  Where the motivating ticket was about compile-time memory
  (T11545, T15304, T26425), residency remains gated via max_bytes_used,
  now with a residency-appropriate tolerance.
  
  max_bytes_used is dropped where residency was only ever an accident of
  'all':
  
  * T15630, T15630a, T20261: the underlying tickets (#15630, #20261)
    contain no memory data at all. One is a simplifier-ticks blowup and
    the other is stated entirely in allocation numbers, so the 20%
    window never had teeth.
  
  * T21839c: #21839's measurements show residency essentially flat
    (+0.16%) while allocations moved +7%, so allocations are the
    discriminating metric. They are already gated at 1% via
    collect_compiler_runtime. The ghc/max gate had previously broken CI
    spuriously (9fd11585eb widened it from 1% to 10% for that reason).
  
  Allocation tolerances are tightened to the testsuite's conventional 2%
  where 'all' previously left them at 10-20%.
  
  Assisted-by: Claude Fable 5
  

• 72dd2432
  by Simon Jakobi at 2026-09-02T07:18:06-04:00

  testsuite: Remove the 'all' metric argument of collect_stats
  
  'all' gated bytes allocated, max_bytes_used and peak_megabytes_allocated
  at a single tolerance, although their noise profiles are incompatible,
  making such tests either flaky or toothless (#27653).
  
  Closes #27653.
  
  Assisted-by: Claude Fable 5
  
  
  

• 2228cb30
  by Simon Jakobi at 2026-09-02T07:18:06-04:00

  testsuite: Make the deviation argument of collect_stats mandatory
  
  Almost every caller passes an explicit tolerance matched to the
  metric's noise profile, and the silent 20% default is far slacker than
  'bytes allocated' merits. Only two tests relied on it. They now state
  their tolerance explicitly:
  
  large-project gets 10%, in line with other large compile-time tests.
  
  T9848 gets 2%: its metric is byte-for-byte deterministic across CI
  jobs and platforms of a given test_env, has drifted only about 2.5%
  since 2015, and the fusion failure it guards against would show up as
  a roughly +30000% jump.
  
  Assisted-by: Claude Fable 5
  
  
  

• 56291fc5
  by Cheng Shao at 2026-09-02T07:18:45-04:00

  autoconf/ghc-toolchain: bump llvm upper bound to support llvm 23
  
  This commit bumps llvm upper bound to support llvm 23.
  

• 20eb3f41
  by Cheng Shao at 2026-09-02T07:18:45-04:00

  rts: fix compilation issues with clang 23
  
  clang 23 has broadened `-Wall`/`-Wextra` ranges, exposing some minor
  issues in the rts when building with validate flavours:
  
  - Unused locals
  - `#pragma GCC diagnostic pop` mismatch
  
  This commit fixes those.
  

• 9e7739ab
  by Simon Jakobi at 2026-09-03T13:45:43-04:00

  Add -Wimplicit-field-strictness (#16836)
  
  This opt-in warning fires when a data constructor field lacks an
  explicit strictness annotation (`!` or `~`).  It complements the
  LazyFieldAnnotations extension (4762a8bf30f) from GHC proposal 752,
  which makes `~` annotations available for this purpose.
  
  Deciding which fields to report requires their levity, so the check
  runs after typechecking.  To keep the noise down, the diagnostic is
  emitted once per data declaration, grouped by constructor.
  
  Closes #16836.
  
  Assisted-by: Claude Fable 5
  

• 6a44d591
  by mangoiv at 2026-09-03T13:46:22-04:00

  simplifier: remove a bogus `assert` in `rebuild_app'` in `GHC.CoreToStg.Prep.cpeApp`.
  
  Prior to this commit
      commit 08bc245be70d95801bc1138804ed1de9474fbdc0
      Author: sheaf <sam.derbyshire@gmail.com>
      Date:   Sat Feb 28 16:30:43 2026 +0100
  
      Clean up join points, casts & ticks
  
      This commit shores up the logic dealing with casts and ticks occurring
      in between a join point binding and a jump
  
  any `PlaceRuntime` ticks we observed were profiling ticks, even though that
  isn't necessary.
  The more liberal rules in the above commit allow e.g. breakpoint ticks
  (which are valid PlaceRuntime ticks) to legitimately appear in an argument
  position.
  
  Fixes #27556
  

• eaa95a6f
  by Andrei Borzenkov at 2026-09-04T08:08:40-04:00

  Parentheses in prefix GADT constructors (#27423)
  
  Updated `splitLHsGadtTy` to allow looking
  through the parentheses for inner binders. General example
  of a code pattern that's allowed now:
  
    data S a where
      MkS :: (forall a. S a)
  
  That should work now with any combination of nested
  foralls and parentheses.
  
  We don't perform parenthesis unwrapping for record
  GADT constructors in accordance with GHC Proposal #402.
  
  To this end `con_inner_bndrs` no longer stores plain forall
  telescopes: `[HsForAllTelescope pass]` is replaced with
  `[LHsGadtTelescope pass]`, a new `HsArg`-style type whose
  `HsGadtForAll` holds an inner telescope and whose `HsGadtPar`
  holds a pair of parentheses. The parentheses carry no meaning
  for renaming or type checking; the only reason to record them
  is exact-printing.
  
  Updated `pprConDecl` to improve the `parse == parse . ppr . parse`
  property of GADT pretty-printing.
  
  The pretty printer can now output code that's similar to this:
  
    data T a where
      MkT1 :: (forall a. T a)
      MkT2 :: forall . forall a. T a
  
  These are special cases of inner forall binders
  for prefix GADT constructors, when we have either
  implicit or zero explicit outer binders.
  

• 639456a8
  by Evgeny Malyshev at 2026-09-04T08:09:25-04:00

  HsPat: Add spacing to unary tuple patterns
  
  Use hsep when printing unary boxed TuplePat applications so that the
  MkSolo constructor is separated from its argument. The old hcat rendered
  wildcard and parenthesized arguments as MkSolo_ and MkSolo().
  
  Add T27034 to exercise the HsPat splice-dump path with wildcard and
  variable arguments, and update existing affected golden output.
  
  Fixes #27034
  
  Assisted-By: OpenAI Codex
  

• 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@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
  

• 1b4a622f
  by sheaf at 2026-09-17T02:39:13-04:00

  Improvements to type/data family handling
  
  This commit makes several improvements to the treatment of type and data
  families in GHC:
  
    - We consistently use "type family" instead of "type synonym family"
      to avoid a confusion with type synonyms. For example:
  
        - OpenSynFamilyTyCon ==> OpenTypeFamilyTyCon
        - ClosedSynFamilyTyCon => ClosedTypeFamilyTyCon
  
    - Various functions that were specific to data families have been
      renamed to make this clear. For example:
  
        - tyConFamInst_maybe ==> tyConDataFamInst_maybe
        - isFamInstTyCon ==> isDataFamInstTyCon
  
    - 'FamTyConFlav' has been refactored so that all closed type families
      share a single 'ClosedTypeFamilyTyCon' constructor.
      The corresponding 'IfaceFamTyConFlav' type was updated similarly.
  
      This is then used to tidy up the implementation of
      GHC.Core.FamInstEnv.reduceTyFamApp_maybe.
  

• c5aa9098
  by sheaf at 2026-09-17T02:39:13-04:00

  Small refactor of lookupFamInstEnv
  
  This commit reworks the code for looking up family instances in
  GHC.Core.FamInstEnv, reducing duplication a little bit.
  
  No change in behaviour.
  

• a3ad4588
  by sheaf at 2026-09-17T02:39:14-04:00

  Use a type family for boxing unboxed types
  
  This commit overhauls the way in which unboxed types are boxed, as per
  the updated Note [Boxing constructors] in GHC.Builtin.WiredIn.Types.Box.
  
  The main change is to allow boxing to be parametrised by representation,
  e.g. making 'Box ty' a valid type. We achieve this by implementing 'Box'
  using a closed type family:
  
    newtype Box (a :: TYPE r) = Box (BoxTF r)
  
    type BoxTF :: RuntimeRep -> Type
    type family BoxTF r where
      BoxTF IntRep    = BoxInt
      BoxTF Int8Rep   = BoxInt8
      BoxTF WordRep   = BoxWord
      BoxTF LiftedRep = Any @Type
      BoxTF (TupleRep [r1, r2]) = (BoxTF r1, BoxTF r2)
      ...
      BoxTF (SumRep rs) = BoxSum rs
  
  This new design solves the following problems:
  
    - It allows boxing a type whose 'RuntimeRep' has not yet been
      determined (e.g. because we only learn the 'RuntimeRep' after
      constraint solving). That is, 'Box @r a' is a perfectly valid type
      even if 'r' is an unfilled metavariable. This is a requirement
      to fix #25065 (in which we need to box a type whose 'RuntimeRep'
      is only filled in during constraint solving).
  
    - It handles boxing of unboxed tuples and unboxed sums, via recursive
      boxing. See Note [Boxing TupleRep and SumRep] in
      GHC.Builtin.WiredIn.Types.Box.
  
  'Box', 'BoxTF' and all of the boxing data constructors are defined in
  a new 'ghc-internal' module, 'GHC.Internal.Box'. This module contains
  nothing but wired-in declarations, and GHC never loads its interface on
  account of a wired-in thing (GHC.Builtin.Modules.isWiredInOnlyModule);
  see Note [Loading instances for wired-in things] in GHC.Iface.Load.
  
  The individual boxing data constructors are deliberately left as an
  internal implementation detail, and not exported. The intended API is
  via the two new magic 'Id's:
  
    box :: forall {r} (a :: TYPE r). a -> Box a
    unbox :: forall {r} (a :: TYPE r). Box a -> a
  
  exported from 'GHC.PrimOps' (in 'ghc-experimental'). The old boxing
  data types (IntBox, WordBox, FloatBox, DoubleBox, DictBox) are no longer
  exported from base (CLC proposal #421).
  
  We use this new design to consistently desugar:
  
    - parallel comprehensions (GHC.HsToCore.ListComp.{deListComp,dsMcStmt})
    - then/group/using statements (GHC.HsToCore.ListComp.{dsTransStmt,dsMcStmt})
    - recursive do blocks (mdo/rec) (GHC.HsToCore.Expr.dsDo)
    - arrows (GHC.HsToCore.Arrows)
  
  by consistently using 'box'/'unbox' to deal with unboxed types being put
  into big tuples. We also adapt 'GHC.Tc.Gen.Match.{tcMcStmt,tcDoStmt}'
  to create fresh /representation-polymorphic/ type variables for the
  binders that we are going to put into a big tuple (previously, GHC only
  allowed lifted types in that position).
  
  These desugaring of box and unbox is explained in
  Note [Desugaring box & unbox] in GHC.Core.Make.Box. Roughly speaking,
  the desugaring looks like:
  
    box   @r @ty e  ==>  K e
    unbox @r @ty e  ==>  case e of K x -> x
  
  where 'K' is the boxing data constructor at RuntimeRep 'r'. It's
  slightly more complicated than that in practice: we first need to
  insert a cast (see Note [The canonical type of a RuntimeRep]) using the
  new 'CanonicalProv' 'UnivCoProvenance', and unboxed tuples/sums need
  recursive logic explained in Note [box/unbox for unboxed tuples and sums],
  including a specific 'BoxSum' datatypes for unboxed sum (which also
  needed a wired-in type-level list indexing type family (!!)).
  
  The desugaring happens in two ways:
  
    - Occurrences of 'box'/'unbox' emitted by the typechecker are
      eliminated in the 'ds_app_var' case of GHC.HsToCore.Expr.
  
    - Other code that needs to box/unbox emits the appropriate code inline.
      This includes the big tuple machinery of GHC.Core.Make used by the
      desugarer (GHC.HsToCore.{Utils,Binds,Arrows,ListComp}) as well as
      the float-out pass (GHC.Core.Opt.SetLevels).
  
  Core Lint checks that no occurrence of 'box'/'unbox' survives desugaring.
  
  On the way, we overhaul the litany of big tuple functions by introducing
  
    data BigTupleLayout = BoxedElements | BareElements
  
  to distinguish the two kinds of "big tuples" that GHC routinely deals
  with; for example 'mkBigCoreVarTupSolo' becomes 'mkBigCoreVarTup BareElements'.
  All of this code is moved to the new module GHC.Core.Make.BigTuple.
  
  Fixes #20864 #22336 #22473 #25065 #27331
  
  -------------------------
  Metric Decrease:
      T9872a
  -------------------------
  

• 4cf7628a
  by Evgeny Malyshev at 2026-09-17T02:39:56-04:00

  Fix the CompactionFailed documentation link to compact
  
  The old Haddock reference links into base instead of ghc-compact.
  Use an explicit URL because ghc-compact depends on base, not vice versa.
  
  Fixes #27558
  
  Assisted-By: OpenAI Codex
  

• 098bba70
  by Facundo Domínguez at 2026-09-17T14:57:41-04:00

  Remove the call to hoistFlag from processCmdLineP
  
  This call was undesirable because it was causing a reconstruction
  of the list of flag processors.
  
  Even relying on list fusion would not be sufficient because we want
  to replace the list with a data structure with faster lookups to
  address #25763.
  
  The removal is done in two moves:
  
  * We move CmdLineP to CmdLine.hs
  * Then we move the effect of hoisting to processArgs via a new function
    hoistEwM
  

• e01799c7
  by Facundo Domínguez at 2026-09-17T14:57:42-04:00

  Do not create duplicate flag processors for the -W flag
  
  This makes simpler implementing the command line parser with a trie map
  holding flag processors. If we were to allow duplicate flag processors
  for any flag, the trie map would need to be a multimap.
  

• 3875b257
  by Facundo Domínguez at 2026-09-17T14:57:42-04:00

  Replace the list of flag processors with a trie map in `processArgs`
  
  Previously `GHC.Driver.CmdLine.findArg` was called for each
  command-line argument, doing a linear search on the list of flag
  processors each time. This was somewhat costly as the list of flag
  processor has near 2000 elements.
  
  A lookup with a trie map is faster in general, but the speed up is
  only noticeable when calling `GHC.Driver.CmdLine.processArgs` sufficient
  times, so the amount of lookups piles up. This could happen in large
  projects with many units each having many dependencies. If only a
  module needs to be recompiled, the user still needs to wait for all of
  the flag parsing to complete.
  
  The benchmark at testsuite/tests/perf/compiler/cmdline-parser shows a
  10x speed up when using the trie.
  
  The trie map is implemented in `GHC.Data.StringTrie`.
  
  The design is explained in Note [Processing command line argument fast]
  in GHC.Driver.Session.
  
  The commit also:
  * adds two property-based tests for trie map operations,
  * adds a benchmark of the command line parser, and
  * renames the predicate `arg_ok` to `valid_flag_suffix` to decide what
    flag processor should be used when there are multiple matching
    prefixes on a flag.
  
  Fixes #25763.
  

• 5236634a
  by Andreas Klebinger at 2026-09-17T14:58:24-04:00

  Compile Word64{Map,Set} with -O2 always.
  
  This is the hottest code and even if we build GHC with -O0 otherwise -O2
  pays off for these modules.
  
  Fixes #27814.
  

• 545fd4fb
  by ARATA Mizuki at 2026-09-22T15:03:24-04:00

  Change the C types of hs_{bitrev,bswap}{16,32} to match the Haskell types
  
  bitReverse{16,32}# and byteSwap{16,32}# have the type
  Word# -> Word#, but their C correspondents took and
  returned StgWord{16,32}.
  
  The mismatch on bitReverse16# led to the problem reported
  in #27299. Although no similar issue is reported for
  bitReverse32# and byteSwap{16,32}#, it seemed wise to
  change them proactively.
  
  This commit fixes the mismatch by changing the C type.
  
  Fixes #27299
  

• bf17f289
  by fendor at 2026-09-22T15:04:05-04:00

  Don't lose instances from shadowed imported modules with the same name
  
  When we look for instances below the current module, we need to check
  the unit id as well when we check for whether the module is the current
  module, otherwise we ignore modules we import that have the same name as
  the import module.
  
  Adds regression test.
  

• 53eead15
  by Wolfgang Jeltsch at 2026-09-24T20:12:03-04:00

  Correct the documentation of `explicitUnits`
  
  Resolves #27787.
  

• 35bf6f4b
  by Simon Jakobi at 2026-09-24T20:12:49-04:00

  Remove stale specHeader bullet from Note [Don't make fillers for constraint types]
  
  The Note said that Specialise.specHeader also calls mkAbsentFiller.
  abfc224a27c removed that call: the specialiser no longer drops dead
  arguments at all, see Note [Do not drop dead args from specialisations]
  in GHC.Core.Opt.Specialise.
  
  Assisted-by: Claude Fable 5.1
  

• 1abef1ef
  by Wolfgang Jeltsch at 2026-09-25T17:02:07-04:00

  Improve the `mhu-closure` makefile
  

• a79a68ea
  by Wolfgang Jeltsch at 2026-09-25T17:02:07-04:00

  Make `ghci-multi` hide all unneeded packages
  

• d6e72450
  by Wolfgang Jeltsch at 2026-09-25T17:02:07-04:00

  Improve the definition of the home unit closure property
  

• c9a2766d
  by Wolfgang Jeltsch at 2026-09-25T17:02:07-04:00

  Re-implement the home unit closure check
  
  Compared to the previous implementation, the new one has the following
  advantages:
  
    * It is correct.
        - It distinguishes between units that have the same unit ID but
          different ABI hashes.
        - When `-hide-all-packages` is not used, it considers as home unit
          dependencies also units that are made implicitly available
          because they are in the package database.
    * It seems to be faster in usual settings.
        - In particular, it does not have a preparation phase in which it
          merges the dependency information from all home units, so that
          its running time does not grow linearly with the size of the
          package database in normal Cabal scenarios.
    * It is (hopefully) clearer.
    * It is better documented.
  

• fa96acf8
  by Wolfgang Jeltsch at 2026-09-25T17:02:07-04:00

  Remove erroneous GHC flag in `hadrian-multi`
  
  The flag was `-Werror=-Wno-error=incomplete-record-selectors`. Its
  purpose was to permit incomplete record selectors, but because of the
  illegal combination of `-Werror=` and `-Wno-error` it was ignored,
  without any negative consequences.
  

• 9f48a5b9
  by Alan Zimmerman at 2026-09-25T17:02:50-04:00

  EPA: Add specific layout field to AnnList
  
  Up to now AnnList has effectively served to represent lists of things
  having layout, regardless of whether they do or not.
  
  In Haskell, layout is optional in many places, as there is also an
  alternative syntax using braces and semi-colons, which is free-form.
  
  This commit introduces AnnListLayout, a data structure capturing this
  distinction.
  
  It is deliberately set up similarly to EpLayout, so that these two can
  be merged in time.
  
  The transition is done mechanically, where AnnListBraces is not used
  yet, the original Nothing case maps to AnnListNoLayout, and the Just
  case to AnnListLayout.
  
  Later commits will fine tune these against the actual parser layout.
  

• ae260fb6
  by mangoiv at 2026-09-29T15:01:26+02:00

  configure: fix sed script and subst tooldir script
  
  Fixes #27672
  
  Metric Decrease:
      LinkableUsage01
      MultiLayerModulesTH_OneShot
      T10547
      T12234
      T12425
      T13035
      T13820
      T18140
      T18730
      T18923
      T9198
      TcPlugin_RewritePerf
      mhu-perf
  

394 changed files:

• .gitlab-ci.yml
• .gitlab/ci.sh
• + changelog.d/25763-cmdline-opt
• + changelog.d/26610
• + changelog.d/27556
• + changelog.d/27732
• + changelog.d/T27629
• + changelog.d/T27749
• + changelog.d/T27764
• + changelog.d/T27788-js-selector
• + changelog.d/allow-gadt-prefix-con-parens
• + changelog.d/boxing-family
• + changelog.d/clc-421
• + 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/implicit-field-strictness-warning
• changelog.d/lazy-field-annotations
• + changelog.d/llvm-23
• + changelog.d/ncg-x86-bit-test-instructions
• + changelog.d/select-io-manager
• compiler/GHC/Builtin.hs
• compiler/GHC/Builtin/KnownKeys.hs
• compiler/GHC/Builtin/Modules.hs
• compiler/GHC/Builtin/Uniques.hs
• compiler/GHC/Builtin/WiredIn/Ids.hs
• compiler/GHC/Builtin/WiredIn/Prim.hs
• compiler/GHC/Builtin/WiredIn/TypeLits.hs
• compiler/GHC/Builtin/WiredIn/Types.hs
• + compiler/GHC/Builtin/WiredIn/Types/Box.hs
• 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/Coercion.hs
• compiler/GHC/Core/Coercion/Axiom.hs
• compiler/GHC/Core/DataCon.hs
• compiler/GHC/Core/FamInstEnv.hs
• compiler/GHC/Core/Lint.hs
• compiler/GHC/Core/Make.hs
• + compiler/GHC/Core/Make/BigTuple.hs
• + compiler/GHC/Core/Make/Box.hs
• compiler/GHC/Core/Opt/SetLevels.hs
• compiler/GHC/Core/Opt/Specialise.hs
• compiler/GHC/Core/Opt/WorkWrap/Utils.hs
• compiler/GHC/Core/TyCo/Ppr.hs
• compiler/GHC/Core/TyCo/Rep.hs
• compiler/GHC/Core/TyCon.hs
• compiler/GHC/Core/Type.hs
• compiler/GHC/Core/Utils.hs
• compiler/GHC/CoreToStg.hs
• compiler/GHC/CoreToStg/AddImplicitBinds.hs
• compiler/GHC/CoreToStg/Prep.hs
• compiler/GHC/Data/FastString.hs
• + compiler/GHC/Data/StringTrie.hs
• compiler/GHC/Data/Word64Map/Internal.hs
• compiler/GHC/Data/Word64Map/Strict/Internal.hs
• compiler/GHC/Data/Word64Set/Internal.hs
• compiler/GHC/Driver/CmdLine.hs
• compiler/GHC/Driver/Downsweep.hs
• compiler/GHC/Driver/Env.hs
• compiler/GHC/Driver/Errors/Ppr.hs
• compiler/GHC/Driver/Errors/Types.hs
• compiler/GHC/Driver/Flags.hs
• compiler/GHC/Driver/GenerateCgIPEStub.hs
• compiler/GHC/Driver/Main/Compile.hs
• compiler/GHC/Driver/Main/Passes.hs
• compiler/GHC/Driver/Session.hs
• compiler/GHC/Hs/Decls.hs
• compiler/GHC/Hs/Doc.hs
• compiler/GHC/Hs/Expr.hs
• compiler/GHC/Hs/Extension/Pass.hs
• compiler/GHC/Hs/Instances.hs
• compiler/GHC/Hs/Pat.hs
• compiler/GHC/Hs/Type.hs
• compiler/GHC/Hs/Utils.hs
• compiler/GHC/HsToCore/Arrows.hs
• compiler/GHC/HsToCore/Binds.hs
• compiler/GHC/HsToCore/Expr.hs
• compiler/GHC/HsToCore/ListComp.hs
• compiler/GHC/HsToCore/Quote.hs
• compiler/GHC/HsToCore/Utils.hs
• compiler/GHC/Iface/Decl.hs
• compiler/GHC/Iface/Ext/Ast.hs
• compiler/GHC/Iface/Load.hs
• compiler/GHC/Iface/Rename.hs
• compiler/GHC/Iface/Syntax.hs
• compiler/GHC/Iface/Tidy.hs
• compiler/GHC/IfaceToCore.hs
• compiler/GHC/Parser.y
• compiler/GHC/Parser/Annotation.hs
• compiler/GHC/Parser/PostProcess.hs
• compiler/GHC/Rename/Expr.hs
• compiler/GHC/Rename/HsType.hs
• compiler/GHC/Rename/Module.hs
• compiler/GHC/Stg/Debug.hs
• compiler/GHC/Stg/Lint.hs
• compiler/GHC/StgToJS/Apply.hs
• compiler/GHC/StgToJS/CodeGen.hs
• compiler/GHC/StgToJS/Symbols.hs
• compiler/GHC/Tc/Deriv.hs
• compiler/GHC/Tc/Deriv/Generate.hs
• compiler/GHC/Tc/Deriv/Generics.hs
• compiler/GHC/Tc/Errors/Ppr.hs
• compiler/GHC/Tc/Errors/Types.hs
• compiler/GHC/Tc/Gen/Expr.hs
• compiler/GHC/Tc/Gen/HsType.hs
• compiler/GHC/Tc/Gen/Match.hs
• compiler/GHC/Tc/Gen/Pat.hs
• compiler/GHC/Tc/Gen/Splice.hs
• compiler/GHC/Tc/Instance/Family.hs
• compiler/GHC/Tc/Instance/Typeable.hs
• compiler/GHC/Tc/Module.hs
• compiler/GHC/Tc/Solver/Default.hs
• compiler/GHC/Tc/Solver/FunDeps.hs
• compiler/GHC/Tc/TyCl.hs
• compiler/GHC/Tc/TyCl/Instance.hs
• compiler/GHC/Tc/Utils/Backpack.hs
• compiler/GHC/Types/CompleteMatch.hs
• compiler/GHC/Types/Error/Codes.hs
• compiler/GHC/Types/Hint.hs
• compiler/GHC/Types/Hint/Ppr.hs
• compiler/GHC/Types/Id.hs
• compiler/GHC/Types/Id/Info.hs
• compiler/GHC/Types/Id/Make.hs
• compiler/GHC/Types/Tickish.hs
• compiler/GHC/Types/TyThing.hs
• compiler/GHC/Types/TyThing/Ppr.hs
• compiler/GHC/Types/Unique.hs
• compiler/GHC/Unit/Env.hs
• compiler/GHC/Unit/State.hs
• compiler/Language/Haskell/Syntax/Decls.hs
• compiler/Language/Haskell/Syntax/Type.hs
• compiler/ghc.cabal.in
• configure.ac
• distrib/configure.ac.in
• docs/users_guide/exts/gadt_syntax.rst
• docs/users_guide/exts/strict.rst
• docs/users_guide/exts/type_data.rst
• docs/users_guide/runtime_control.rst
• docs/users_guide/using-warnings.rst
• ghc/GHC/Driver/Session/Mode.hs
• hadrian/ghci-multi-cabal.in
• 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/Base.hs
• libraries/base/src/GHC/Exts.hs
• libraries/base/src/GHC/RTS/Flags.hs
• libraries/base/tests/all.T
• libraries/ghc-internal/ghc-internal.cabal.in
• libraries/ghc-internal/include/RtsIfaceSymbols.h
• + libraries/ghc-internal/src/GHC/Internal/Box.hs
• libraries/ghc-internal/src/GHC/Internal/Conc/IO.hs
• libraries/ghc-internal/src/GHC/Internal/Event/Thread.hs
• libraries/ghc-internal/src/GHC/Internal/Exts.hs
• libraries/ghc-internal/src/GHC/Internal/IO/Exception.hs
• libraries/ghc-internal/src/GHC/Internal/RTS/Flags.hsc
• libraries/ghc-internal/src/GHC/Internal/TypeNats.hs
• libraries/ghc-internal/src/GHC/Internal/Types.hs
• linters/lint-codes/LintCodes/Static.hs
• 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
• m4/subst_tooldir.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/ProfHeap.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/eventlog/EventLog.c
• rts/include/rts/Flags.h
• rts/include/rts/RtsToHsIface.h
• rts/include/rts/storage/Closures.h
• rts/include/stg/MiscClosures.h
• rts/include/stg/Prim.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/prim/atomic.c
• rts/prim/bitrev.c
• rts/prim/bswap.c
• 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/driver/README.md
• testsuite/driver/testlib.py
• testsuite/tests/MiniQuickCheck.hs
• testsuite/tests/arrows/should_run/all.T
• + testsuite/tests/arrows/should_run/arrowrun005.hs
• + testsuite/tests/arrows/should_run/arrowrun005.stdout
• + 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/count-deps/CountDepsParser.stdout
• + testsuite/tests/deSugar/should_compile/T25065a.hs
• testsuite/tests/deSugar/should_compile/all.T
• + testsuite/tests/deSugar/should_run/T20864.hs
• + testsuite/tests/deSugar/should_run/T20864.stdout
• + testsuite/tests/deSugar/should_run/T25065b.hs
• + testsuite/tests/deSugar/should_run/T25065b.stdout
• testsuite/tests/deSugar/should_run/all.T
• testsuite/tests/driver/all.T
• testsuite/tests/driver/multipleHomeUnits/mhu-closure/Makefile
• testsuite/tests/driver/multipleHomeUnits/mhu-closure/mhu-closure.stderr
• testsuite/tests/driver/multipleHomeUnits/mhu-closure/mhu-closure.stdout
• + testsuite/tests/driver/stringtrie.hs
• + testsuite/tests/driver/stringtrie.stdout
• − testsuite/tests/gadt/T14320.stderr
• testsuite/tests/gadt/T18191.hs
• testsuite/tests/gadt/T18191.stderr
• + testsuite/tests/gadt/T27423a.hs
• + testsuite/tests/gadt/T27423b.hs
• + testsuite/tests/gadt/T27423b.stderr
• testsuite/tests/gadt/all.T
• testsuite/tests/ghc-api/T25121_status.stdout
• testsuite/tests/ghc-api/exactprint/T22919.stderr
• testsuite/tests/ghc-api/exactprint/ZeroWidthSemi.stderr
• + 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/ghci/prog-mhu008/Makefile
• + testsuite/tests/ghci/prog-mhu008/a/M.hs
• + testsuite/tests/ghci/prog-mhu008/all.T
• + testsuite/tests/ghci/prog-mhu008/b/M.hs
• + testsuite/tests/ghci/prog-mhu008/prog-mhu008.script
• + testsuite/tests/ghci/prog-mhu008/prog-mhu008.stdout
• + testsuite/tests/ghci/prog-mhu008/unitA
• + testsuite/tests/ghci/prog-mhu008/unitB
• + testsuite/tests/indexed-types/should_run/T27331.hs
• + testsuite/tests/indexed-types/should_run/T27331.stdout
• + testsuite/tests/indexed-types/should_run/T27331b.hs
• + testsuite/tests/indexed-types/should_run/T27331b.stdout
• + testsuite/tests/indexed-types/should_run/T27331b_Plugin.hs
• testsuite/tests/indexed-types/should_run/all.T
• 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/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/linters/notes.stdout
• testsuite/tests/module/mod185.stderr
• testsuite/tests/parser/should_compile/DumpParsedAst.stderr
• testsuite/tests/parser/should_compile/DumpParsedAstComments.stderr
• testsuite/tests/parser/should_compile/DumpRenamedAst.stderr
• testsuite/tests/parser/should_compile/DumpSemis.stderr
• testsuite/tests/parser/should_compile/KindSigs.stderr
• testsuite/tests/parser/should_compile/T15279.stderr
• testsuite/tests/parser/should_compile/T20718.stderr
• testsuite/tests/parser/should_compile/T20846.stderr
• + testsuite/tests/perf/compiler/T25763.stderr
• testsuite/tests/perf/compiler/all.T
• testsuite/tests/perf/compiler/large-project/all.T
• testsuite/tests/perf/space_leaks/all.T
• + testsuite/tests/primops/should_run/T27299.hs
• + testsuite/tests/primops/should_run/T27299.stdout
• testsuite/tests/primops/should_run/all.T
• testsuite/tests/printer/Makefile
• + testsuite/tests/printer/T27423c.hs
• testsuite/tests/printer/Test20297.stdout
• testsuite/tests/printer/Test24533.stdout
• testsuite/tests/printer/all.T
• 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/T27556.hs
• + testsuite/tests/simplCore/should_compile/T27556.script
• + 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/th/T17380.stderr
• testsuite/tests/th/T18612.stderr
• + testsuite/tests/th/T27034.hs
• + testsuite/tests/th/T27034.stderr
• testsuite/tests/th/T8761.stderr
• testsuite/tests/th/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/T27664.hs
• testsuite/tests/typecheck/should_compile/all.T
• + testsuite/tests/warnings/should_compile/T16836a.hs
• + testsuite/tests/warnings/should_compile/T16836a.stderr
• + testsuite/tests/warnings/should_compile/T16836b.hs
• + testsuite/tests/warnings/should_compile/T16836c.hs
• + testsuite/tests/warnings/should_compile/T16836c.stderr
• + testsuite/tests/warnings/should_compile/T16836d.hs
• + testsuite/tests/warnings/should_compile/T16836d.stderr
• testsuite/tests/warnings/should_compile/all.T
• + testsuite/tests/warnings/should_fail/WExpectedNoArgError.stderr
• testsuite/tests/warnings/should_fail/all.T
• utils/check-exact/ExactPrint.hs
• utils/check-exact/Main.hs
• utils/check-exact/Transform.hs
• utils/check-exact/Utils.hs
• utils/deriveConstants/Main.hs
• utils/ghc-toolchain/src/GHC/Toolchain/Program.hs
• utils/haddock/haddock-api/src/Haddock/Backends/Hoogle.hs
• utils/haddock/haddock-api/src/Haddock/Convert.hs
• utils/haddock/haddock-api/src/Haddock/GhcUtils.hs
• utils/haddock/haddock-api/src/Haddock/Interface/Rename.hs
• utils/haddock/haddock-api/src/Haddock/Types.hs
• utils/hsc2hs
• utils/jsffi/dyld.mjs

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