Cheng Shao pushed to branch wip/terrorjack/asan at Glasgow Haskell Compiler / GHC

Commits:

• 9b714c4c
  by Zubin Duggal at 2026-07-05T09:40:36+05:30

  CorePrep: Don't speculatively evaluate bindings that we have already discovered to be absent
  
  In #25924, we segfault because speculation forces a projection out of a RUBBISH dictionary
  (which we generated because it absent).
  
  Solution: Don't speculate on bindings we already know are absent.
  
  Fixes 25924
  

• 4a59b3ee
  by Zubin Duggal at 2026-07-05T09:40:36+05:30

  Don't make absent fillers for terminating types
  
  In #25924 we discovered that we could speculatively evaluate an absent filler
  for a dictionary, and project a field (a superclass selector) out of it,
  resulting in segfaults.
  
  Solution: Never make an absent filler or rubbish literal for a terminating type
  like a dictionary. mkAbsentFiller returns Nothing for isTerminatingType, so
  worker/wrapper and the specialiser keep the real argument instead.
  
  Some small metric decreases because we do a little less work in the
  simplifier now.
  
  Metric Decrease:
      T9872a
      T9872b
      T9872c
      TcPlugin_RewritePerf
  

• 383ddcd4
  by Alan Zimmerman at 2026-07-06T07:08:16-04:00

  EPA: Move the 'where' annotation for PatSynBind
  
  This allows us to move it out of the MatchGroup exact print annotation
  too
  

• 66d1a5d5
  by fendor at 2026-07-07T16:57:56-04:00

  Add 'backendInfoTableMapValidity' backend predicate
  
  Check whether the backend supports the `-finfo-table-map` flag and
  ignore it otherwise.
  
  Improve by-design documentation of `backendCodeOutput`.
  
  `Backend` is **abstract by design**. Make this clearer in
  `backendCodeOutput` which is incorrectly being used as a proxy for
  `Backend`.
  
  Instead, define the desired property predicates in GHC.Driver.Backend
  In the process, make `backendCodeOutput` total.
  

• 74f1071d
  by fendor at 2026-07-07T16:57:56-04:00

  Add failing test for `-finfo-table-map` and bytecode backend
  
  If you compile a module using the bytecode backend, with
  -finfo-table-map, then the info table map doesn't get populated for the
  module.
  
  This is because the -finfo-table-map code path is implemented mostly in
  the StgToCmm phase which isn't run when creating bytecode.
  
  Ticket #27039
  

• 28d63bca
  by mangoiv at 2026-07-07T16:59:16-04:00

  ci: don't fail nightly if there have been no changes that night
  
  Fixes #27127
  

• 4ebfc478
  by Rodrigo Mesquita at 2026-07-08T04:47:53-04:00

  ttg: Using ShortText over FastString in the AST
  
  To make the AST independent of GHC, this commit replaces usages of
  `FastString` with `HText` in the AST, killing the last edge from
  Language.Haskell.* to GHC.* modules.
  
  Even though we /do/ want to use FastStrings in general -- critically in
  Names or Ids -- there is no particular reason for the FastStrings that
  occur in the AST proper to be FastStrings. Strings in the AST are
  typically unique and don't benefit particularly from being interned
  FastStrings with Uniques for fast comparison.
  
  `HText` is a type synonym for `ShortText` which uses GHC's Modified
  UTF-8 encoding exclusively.
  
  Modified UTF-8 must be used to represent the Haskell AST because the
  Haskell Report allows surrogate code points. `Data.Text.Text` functions
  use Standard UTF-8 which replace surrogates with a placeholder value,
  thus `Data.Text.Text` is unsuitable for AST strings. See the
  `Language.Haskell.Syntax.Text` module header for more details.
  
  Final progress towards #21592
  
  Closes #21628
  

• d910b353
  by Simon Peyton Jones at 2026-07-08T04:48:36-04:00

  Update equality-type documenation in GHC.Builtin.Types.Prim
  
  Fix #27466
  

• b2530542
  by Simon Peyton Jones at 2026-07-08T04:48:36-04:00

  Honour -dsuppress-coercions in GHC.Core.TyCo.pprCo
  
  Fixes #27467
  

• 9a73179a
  by Facundo Domínguez at 2026-07-08T04:49:26-04:00

  Add item to MR checklist asking to squash fixup commits after approval
  
  The checklist has an item that reads
  
      All commits are either individually buildable or squashed.
  
  This item could be checked immediately after sending the merge request
  though. If reviewers ask for amends later on, and the author amends
  the merge request, there was no item that would remind the contributors
  to squash the fixup commits before landing.
  
  This commit adds a new item
  
      After all approvals and before landing: all fixup commits are squashed with their originating commits.
  
  which should be harder to mark as done before approvals have been given.
  

• ed09895d
  by Andreas Klebinger at 2026-07-08T16:53:27-04:00

  Fix a profiling race condition resulting in segfaults.
  
  StgToCmm: Don't assume tagged FUN closures in closureCodeBody.
  When entering a closure the self/node pointer might not be tagged in
  some situations when a thunk is evaluated by multiple threads.
  So we most AND away the tag bits rather than subtracting an expected tag.
  
  Apply.cmm: Fix a race condition occuring when a thunk is mutated during GC.
  
  In stg_ap_0_fast when might need to run GC before entering a thunk. If this happens
  another thread or the GC itself might mutate the closure making entering it no longer
  valid. We now check for this.
  
  Add test and changelog for #27123 fixes.
  

• 67c03eb2
  by Cheng Shao at 2026-07-08T16:54:09-04:00

  ghc-heap: fix invalid srtlen returned by peekItbl when no-TNTC
  
  This patch fixes the no-TNTC code path of `peekItbl` so that it looks
  at the right memory address when reading the `srt` field from the
  `StgInfoTable_` struct. Also adds a `T27465` regression test that
  reproduces the bug on no-TNTC builds before the fix. Fixes #27465.
  
  Co-authored-by: Codex <codex@openai.com>
  

• 2ecabb4f
  by Zubin Duggal at 2026-07-09T09:23:25-04:00

  hadrian: binary-dist-dir should not be the default target
  
  Revert behaviour to pre 23c9b6c392f52ec9d7a8618b204ff6b885f5fba2
  
  In 23c9b6c392f52ec9d7a8618b204ff6b885f5fba2, we applied the following behaviour change:
  
  ```
  hadrian: Build stage 2 cross compilers
  ...
  * hadrian: Make binary-dist-dir the default build target. This allows us
    to have the logic in one place about which libraries/stages to build
    with cross compilers. Fixes #24192
  ```
  
  This is a major regression to development experience, a plain hadrian/build
  --freeze1 now takes ages because we rebuild all docs (which need to go in the
  binary dist dir).
  
  `binary-dist-dir` is the wrong default target for regular GHC development work
  
  Fixes #27445
  

• e16388e3
  by Zubin Duggal at 2026-07-09T09:23:25-04:00

  .gitignore: Add the hadrian system.config introduced by commit 23c9b6c392f52ec9d7a8618b204ff6b885f5fba2
  
  Since
  
  commit 23c9b6c392f52ec9d7a8618b204ff6b885f5fba2
  Author: Matthew Pickering <matthewtpickering@gmail.com>
  Date:   Thu Dec 21 16:17:41 2023 +0000
  
      hadrian: Build stage 2 cross compilers
  
  ./configure produces /hadrian/cfg/system.config.{host,target}
  
  Add these to .gitignore
  

• 7e8abf41
  by Alan Zimmerman at 2026-07-09T09:24:12-04:00

  EPA: Replace AnnListItem with simply [TrailingAnn]
  
  Remove the unnecessary wrapper around a single field.
  

• 29032f17
  by Zubin Duggal at 2026-07-09T09:24:58-04:00

  testsuite: Keep real reason for fragile test failures
  

• c34e03a7
  by Zubin Duggal at 2026-07-09T09:24:58-04:00

  testsuite: Fall back to the failure reason for empty JUnit bodies
  

• 409d40f0
  by Zubin Duggal at 2026-07-09T09:24:58-04:00

  testsuite: Show output diffs in JUnit output
  
  Also refactor compare_outputs to return essentially a `Maybe Diff`
  (`CompareOutput`) instead of a bool, but more pythonic. This
  allows us to pass the diff through nice.
  

• 06fee1ab
  by Zubin Duggal at 2026-07-09T09:24:58-04:00

  perf notes: include stat deviation and acceptance window in notes so they show up in gitlab
  

• 57c0f32c
  by mangoiv at 2026-07-10T11:08:38-04:00

  driver: enable -finter-module-far-jumps by default
  
  this fixes a compatibility bug with certain binutils/gcc versions where
  we were seeing jump offset overflow errors.
  This commit can probably reverted if we stop supporting the problematic
  binutils/gcc verions (2.44 and 14.2, respectively)
  
  Reolves #26994
  

• 4396a6f2
  by Andrea Vezzosi at 2026-07-10T11:09:25-04:00

  [Fix #27287] preserve ModBreaks in ModIface
  

• ed261a7e
  by Cheng Shao at 2026-07-14T17:59:38-04:00

  hadrian: fix HLS support
  
  This patch fixes hadrian's HLS support so one can rely on HLS when
  working on the hadrian codebase. Fixes #27480.
  
  Not building/linking shared libraries for hadrian is a severely
  premature optimization; this top-level setting in `cabal.project` only
  affects home packages while the dependencies in the cabal store are
  built with vanilla/dynamic anyway, and even adding dynamic builds to
  home packages would not be costly due to cabal's usage of
  `-dynamic-too`.
  

• eee8ec5b
  by Cheng Shao at 2026-07-14T18:00:20-04:00

  compiler: fix miscompiled %load_relaxed, add missing %store_relaxed
  
  This patch fixes the %load_relaxed cmm primop compilation logic to
  correctly use relaxed memory ordering, and adds the missing
  %store_relaxed primop. Parsing logic of %load/%store with explicit
  ordering is covered in the AtomicFetch test case. Fixes #27483.
  
  Co-authored-by: Codex <codex@openai.com>
  

• 1718230f
  by Alan Zimmerman at 2026-07-14T18:01:06-04:00

  EPA: Keep binds and sigs together in HsValBindsLR
  
  We combine them into a single list for GhcPs, wrapped in the
  ValBind data type, which is the bind equivalent of ValD, having
  constructors for binds and sigs.
  
  This simplifies exact print processing, especially when using it to
  update the contents of local binds, as we no longer need AnnSortKey
  BindTag
  

• 6bd1ad2a
  by Andreas Klebinger at 2026-07-14T18:01:49-04:00

  Bump nofib submodule to account for MonoLocalBinds.
  
  New versions of GHC enable MonoLocalBinds by default.
  This breaks some of the benchmarks. I've fixed this and
  this bump pulls in that fix.
  

• 7eb0f1c9
  by Cheng Shao at 2026-07-14T18:02:31-04:00

  testsuite: fix bytecodeIPE test under +ipe flavours
  
  This patch fixes the bytecodeIPE test under +ipe flavours. It used to
  fail under +ipe because the RTS is built with IPE info, then
  stg_AP_info in RTS carries IPE info, so whereFrom wouldn't return
  Nothing. Now the test checks IPE info of a datacon in the ghci-loaded
  module which is not affected by whether the RTS is built with IPE info
  or not. Fixes #27498.
  
  Co-authored-by: Codex <codex@openai.com>
  

• ef038aae
  by cydparser at 2026-07-15T04:35:41-04:00

  Reduce bytes allocated for `capabilities` in RTS (fixes #27487)
  
  In rts/Capability.c, `capabilities` is an array of pointers, but it was allocated as if it were an
  array of Capability's.
  

• d377e83e
  by Cheng Shao at 2026-07-15T04:36:27-04:00

  rts: fix missing UNTAG in stg_readTVarIOzh
  
  This patch fixes missing UNTAG on the current value closure read from
  StgTVar. UNTAG is a no-op when it's stg_TREC_HEADER_info which is word
  aligned; it may be a tagged closure, and reading info table from the
  tagged address is an unaligned load which may cause issues on
  platforms with strict alignment requirements.
  
  Co-authored-by: Codex <codex@openai.com>
  

• 8ed03842
  by Cheng Shao at 2026-07-15T04:36:27-04:00

  rts: fix missing UNTAG in stg_control0zh_ll
  
  This patch fixes missing UNTAG on the cont closure returned by
  captureContinuationAndAbort. In case it's not NULL,
  captureContinuationAndAbort returns a tagged StgContinuation closure,
  in which case it must be untagged before accessing the
  apply_mask_frame field.
  
  In the past it worked out of luck: when apply_mask_frame was NULL then
  mask_frame_offset is also 0 so the control flow didn't diverge to a
  wrong path. Still, this is horribly wrong and will crash once
  StgContinuation struct is refactored and fields are shuffled around.
  
  Co-authored-by: Codex <codex@openai.com>
  

• 5aa7000a
  by Cheng Shao at 2026-07-15T04:37:08-04:00

  compiler: fix redundant AP thunk codegen when not using -ticky-ap-thunk
  
  This patch fixes a double negation confusion in !7525 that results in
  some redundant AP thunk code generation when not using
  -ticky-ap-thunk. Now, we use `stgToCmmUseStdApThunk` to indicate
  whether precomputed AP thunks in the RTS should be used, which
  defaults to `True`, unless `-ticky-ap-thunk` is passed.
  `-finfo-table-map` now also implies `-ticky-ap-thunk`, since when
  doing IPE profiling we want the generated AP thunks to be unique.
  Fixes #27502.
  
  -------------------------
  Metric Decrease:
      T3064
  -------------------------
  
  Co-authored-by: Codex <codex@openai.com>
  

• d43a7b7a
  by Brian McKenna at 2026-07-15T20:10:04+02:00

  Strip ticks when desugaring bool guards
  
  The special `considerAccessible` pattern was broken when compiling
  with debug info. Compiling with debug info wraps expressions with
  `SourceNote` ticks, which broke the internals of the
  `desugarBoolGuard` function. Ticks are now ignored within this
  function.
  
  Fixes #27360
  

• ede4b17b
  by Ben Gamari at 2026-07-15T22:59:53-04:00

  base: Display ExceptionContext in WhileHandling's textual description
  
  As originally-implemented the implementation for
  `WhileHandling(displayExceptionAnnotation)` would display the
  `ExceptionContext` of the exception which it carries (as this was the
  behavior of `displayException`, in terms of which
  `displayExceptionAnnotation` was implemented).
  
  However, in 284ffab3 the definition of `SomeException(displayException)`
  was changed to exclude the `ExceptionContext`. This means that
  `WhileHandling(displayExceptionAnnotation)` fails to describe the
  provenance of the exception which it captures, greatly limiting its
  utility.
  
  Return the implementation to its originally-specified behavior by
  implementing `WhileHandling(displayExceptionAnnotation)` in terms of
  `displayExceptionWithInfo`.
  
  Fixes #27456.
  

• 0f64f348
  by Cheng Shao at 2026-07-16T15:41:08+00:00

  ci: add missing docker permission workaround in abi-test job
  

• 660cb239
  by Cheng Shao at 2026-07-16T19:37:48+00:00

  bindist: Fix make install -j race condition on macos/freebsd
  
  This patch fixes make install -j race condition on macos/freebsd. BSD
  install fails with EEXIST when multiple install processes concurrently
  create the same prefix directory. So we add an `install_dirs`
  prerequisite job that sequentially creates the directories for
  subsequent jobs to work with. Fixes #27499.
  
  Co-authored-by: Codex <codex@openai.com>
  

• 08130257
  by Cheng Shao at 2026-07-16T19:37:48+00:00

  ci: run bindist make install with -j
  
  This patch makes the ci scripts run `make install` with `-j` to reduce
  wall clock time when installing the bindist, see related issue for
  benchmark numbers. This only affects ghc ci logic, the user-facing
  default is up to distributors and is still `-j1`. Closes #27029.
  

• d5ae6906
  by Adam Gundry at 2026-07-17T04:57:43-04:00

  Mark various language extension flags as deprecated (see #27329)
  
  The following language extensions are now deprecated:
  
   - AlternativeLayoutRule
   - AlternativeLayoutRuleTransitional
   - ParallelArrays
   - PolymorphicComponents
   - Rank2Types
  
  In addition, the warning `-Walternative-layout-rule-transitional`
  has been marked as deprecated, as it is emitted only under the
  deprecated extension `XAlternativeLayoutRuleTransitional`.
  

• fe3b059c
  by Andrew Lelechenko at 2026-07-17T04:58:26-04:00

  base: re-export GHC.Environment.getFullArgs from System.Environment
  
  CLC proposal https://github.com/haskell/core-libraries-committee/issues/431
  

• 722236dd
  by sheaf at 2026-07-18T08:48:31-04:00

  Coercion optimisation: avoid double-Sym for InstCo
  
  Ticket #27374 pointed out an issue with GHC.Core.Coercion.Opt.optCoercion's
  handling of InstCo: it contravened (LC2) in Note [The LiftingContext in optCoercion]
  because it applied the ambient 'sym' to a coercion that was then added
  to the lifting context substitution.
  
  Fixes #27374
  
  Co-authored-by: Simon Jakobi <simon.jakobi@gmail.com>
  

• ff70fc75
  by sheaf at 2026-07-18T08:48:31-04:00

  Coercion optimisation: avoid exponential behaviour
  
  The change to coercion optimisation of 'InstCo' in the previous commit
  introduces exponential behaviour to the coercion optimiser. To avoid
  this, this commit provides a way to push in 'Sym' of an already-optimised
  coercion: GHC.Core.Coercion.Opt.mkDeepSymCo.
  
  See Note [Pushing Sym without re-optimising] in GHC.Core.Coercion.Opt.
  

• dfef27f0
  by Duncan Coutts at 2026-07-18T08:49:12-04:00

  Move THREADED_RTS-conditional struct members to end of Capability
  
  Accessing members of the Capability struct from CMM code rely on
  accessor macros. (The macros are generated by deriveConstants).
  
  These macros have a single definition. This means that the offsets of
  all struct members must *not* vary based on THREADED_RTS vs
  !THREADED_RTS. This requires that any struct members that are
  conditional on THREADED_RTS must occur after the unconditional struct
  members. Hence we move all the ones that are conditional on
  THREADED_RTS to the end.
  
  Add a deriveConstants entry for the iomgr member of the Capability
  struct, which was the motivation for this change.
  
  Add warning messages to help our future selves. Debugging this took me
  a couple hours in gdb!
  

• c254e022
  by Duncan Coutts at 2026-07-18T08:49:12-04:00

  Make the IOManager API use CapIOManager rather than Capability
  
  This makes the API somewhat more self-contained and more consistent.
  Now the IOManager API and each of the backends takes just the I/O
  manager structure. Previously we had a bit of a mixture, depending on
  whether the function needed access to the Capability or just the
  CapIOManager.
  
  We still need access to the cap, so we introduce a back reference to
  reach the capability, via iomgr->cap.
  
  Convert all uses in select and poll backends, but not win32 ones.
  Convert callers in the scheduler and elsewhere.
  
  Also convert the three CMM primops that call IOManager APIs. They just
  need to use Capability_iomgr(MyCapability()).
  

• 4f3d8f31
  by Duncan Coutts at 2026-07-18T08:49:12-04:00

  Split posix/MIO.c out of posix/Signals.c
  
  The MIO I/O manager was secretly living inside the Signals file.
  
  Now it gets its own file, like any other self-respecting I/O manager.
  

• 52ce04a9
  by Duncan Coutts at 2026-07-18T08:49:12-04:00

  Rationalise some scheduler run queue utilities
  
  Move them all to the same place in the file.
  
  Make some static that were used only internally.
  
  Also remove a redundant assignment after calling truncateRunQueue that
  is already done within truncateRunQueue.
  

• 75bbdebc
  by Duncan Coutts at 2026-07-18T08:49:12-04:00

  Rename initIOManager{AfterFork} to {re}startIOManager
  
  These are more accurate names, since these actions happen after
  initialisation and are really about starting (or restarting) background
  threads.
  

• 724c0517
  by Duncan Coutts at 2026-07-18T08:49:12-04:00

  Free per-cap I/O managers during shutdown and forkProcess
  
  Historically this was not strictly necessary. The select and win32
  legacy I/O managers did not maintain any dynamically allocated
  resources. The new poll one does (an auxillary table), and so this
  should be freed.
  
  After forkProcess, all threads get deleted. This includes threads
  waiting on I/O or timers. So as of this patch, resetting the I/O
  manager is just about tidying things up. For example, for the poll
  I/O manager this will reset the size of the AIOP table (which
  otherwise grows but never shrinks).
  
  In future however the re-initialising will become neeecessary for
  functionality, since some I/O managers will need to re-initialise
  wakeup fds that are set CLOEXEC.
  

• c007d122
  by Duncan Coutts at 2026-07-18T08:49:12-04:00

  Add a TODO to the MIO I/O manager
  
  The direction of travel is to make I/O managers per-capability and have
  all their state live in the struct CapIOManager. The MIO I/O manager
  however still has a number of global variables.
  
  It's not obvious how handle these globals however.
  

• b65ab7b3
  by Duncan Coutts at 2026-07-18T08:49:12-04:00

  Add a FIXME note in the Poll I/O manager
  

• daf2bd6f
  by Duncan Coutts at 2026-07-18T08:49:12-04:00

  Add missing updateRemembSetPushClosure in poll I/O manager
  
  For the non-moving GC.
  

• e33ca830
  by Duncan Coutts at 2026-07-18T08:49:12-04:00

  Minor doc improvement to struct StgAsyncIOOp member outcome
  
  Mention the enumeration names, as well as their numeric values. The rest
  of the code uses the enum names.
  

• 4edd2579
  by Duncan Coutts at 2026-07-18T08:49:12-04:00

  Minor doc improvements for StgTSOBlockInfo
  
  Clarify that certain union members are used only by certain legacy
  I/O managers. Hopefully we will be able to remove these at some point.
  

• 536bedbb
  by Duncan Coutts at 2026-07-18T08:49:12-04:00

  Avoid exporting various win32-specific rts symbols
  
  The BeginPrivate.h / EndPrivate.h scheme works perfectly well on
  Windows, but all of the rts/win32/*.h files were not using it.
  

• 8139b5ac
  by Duncan Coutts at 2026-07-18T08:49:12-04:00

  Remove wakeupIOManager, ioManagerWakeup and setIOManagerWakeupFd
  
  We no longer need wakeupIOManager for the threaded RTS case, so we can
  remove it and the bits only needed to support it. This includes the
  pipe/eventfd fd shared between the RTS and the in-library I/O manager
  used for waking up the I/O manager thread. The pipe/eventfd still
  exists, but it no longer has to be communicated to the RTS, since the
  RTS no longer needs to use it.
  
  So we remove the RTS API export setIOManagerWakeupFd, and remove uses of
  it within the I/O managers in ghc-internal.
  

• 74fe7c66
  by Duncan Coutts at 2026-07-18T08:49:12-04:00

  Add a new interruptIOManager API for the I/O managers
  
  It will be used to interrupt awaitCompletedTimeoutsOrIO. Also update the
  return type and docs for awaitCompletedTimeoutsOrIO to have it return
  false when it gets interrupted, and have no useful post condition in
  that case.
  

• 38792843
  by Duncan Coutts at 2026-07-18T08:49:13-04:00

  Add interruptIOManager support for select I/O manager
  
  Uses the FdWakup mechanism.
  

• 2f3b00aa
  by Duncan Coutts at 2026-07-18T08:49:13-04:00

  Add interruptIOManager support for poll I/O manager
  
  Uses the FdWakup mechanism.
  
  A quirk we have to cope with is that we now need to poll one more fd --
  the wakeup_fd_r -- but this fd has no corresponding entry in the
  aiop_table. This is awkward since we have set up our aiop_poll_table to
  be an auxilliary table with matching indicies.
  
  The solution this patch uses (and described in the comments) is to have
  two tables: struct pollfd *aiop_poll_table, *full_poll_table;
  and to have the aiop_poll_table alias the tail of the full_poll_table.
  The head entry in the full_poll_table is the extra fd. So we poll the
  full_poll_table, while the aiop_poll_table still has matching indicies
  with the aiop_table.
  
  Hurrah for C aliasing rules.
  

• cee50131
  by Duncan Coutts at 2026-07-18T08:49:13-04:00

  Add interruptIOManager support for win32 legacy I/O manager
  
  And remove unused related helper resetAbandonRequestWait. It is not
  called because the event is created in auto-reset mode, so never needs
  to be reset manually.
  

• cf453143
  by Duncan Coutts at 2026-07-18T08:49:13-04:00

  Note lack of interruptIOManager support for WinIO I/O manager
  
  Though there's a plausible design, we can't sanely test it at the moment
  due to related WinIO bugs. Filed as issue #27403.
  

• 1b74a0ad
  by Duncan Coutts at 2026-07-18T08:49:13-04:00

  Be more explicit about enum IOReadOrWrite values, and type within cmm
  
  Belt and braces.
  

• b388d093
  by Brian McKenna at 2026-07-18T17:51:50-04:00

  Ignore ticks in the pattern-match term oracle
  
  The term-oracle in the pattern-match checker is keyed by a canonical
  form of the scrutinee, computed by `makeDictsCoherent`. That canonical
  form was tick-sensitive: two occurrences of an otherwise identical
  expression that happened to carry different ticks were treated as
  distinct values, breaking long-distance information.
  
  This shows up in practice under `-finfo-table-map`, because the
  desugarer wraps every record-selector use site in a `SourceNote`
  carrying that site's span. For example:
  
       data Box = Box { unBox :: Maybe Int }
       f b = case unBox b of
         Nothing -> 0
         Just _  -> let Just x = unBox b in x
  
  The two `unBox b` expressionss carry different SourceNote spans, the
  pattern-match checker sees them as different, the long-distance
  information from the outer `Just _` branch never reaches the
  let-pattern, and `Just x = unBox b` is wrongly reported as
  non-exhaustive.
  
  We now strip all ticks in `makeDictsCoherent`.  This is documented as
  Wrinkle (UD1) of Note [Unique dictionaries in the TmOracle CoreMap].
  
  Fixes #27314
  

• c23e1acb
  by Mrjtjmn at 2026-07-18T17:52:45-04:00

  Add explanations for unsolved Typeable constraints
  
  This commit adds explanations for unsolved 'Typeable' constraints.
  
  GHC will now provide additional explanations for an unsolved constraint
  of the form 'Typeable ty', explain why GHC did not solve Typeable constraint.
  e.g.:
   - 'ty' is a polymorphic type (e.g. forall a. a -> a)
   - 'ty' is a qualified type (e.g. Eq Int => Int)
   - 'ty' is an unboxed sum type
   - 'ty' is an unreduced type family application
   - 'ty' whose kind is not typeable
  
  Fixes #26532
  

• cbef021e
  by Artem Pelenitsyn at 2026-07-19T07:49:55-04:00

  ghc-internal: Lock.hs: fix typo and indentation

• 42918646
  by Duncan Coutts at 2026-07-19T07:50:36-04:00

  Fix failing test GcStaticPointers for non-moving GC
  
  Minor mistake in asserting something before checking for that same
  thing.
  
  Specifically, Bdescr asserts HEAP_ALLOCED_GC, but Bdescr was being used
  prior to a guard that checks HEAP_ALLOCED_GC. The solution is just to
  move the use of Bdescr after the guard.
  
  Thanks to Simon Jakobi for identifying the problem.
  

• dcbefbf3
  by Cheng Shao at 2026-07-20T10:57:50+02:00

  rts: add is-valid-utf8.c to .ubsan-suppressions
  
  A minor one in `bytestring` that might surface when building with
  +ubsan using clang.
  

• 3cfad4df
  by Cheng Shao at 2026-07-20T10:57:50+02:00

  hadrian: add support for building with AddressSanitizer
  
  This patch adds a +asan flavour transformer to hadrian to build all
  stage1+ C/C++ code with AddressBehaviorSanitizer. This is particularly
  useful to catch potential out-of-bounds and use-after-free bugs in the
  RTS codebase.
  

• 0886abed
  by Cheng Shao at 2026-07-20T10:57:50+02:00

  ci: add ubsan+asan job
  
  We now have a
  `x86_64-linux-fedora43-quick-validate+debug_info+ubsan+asan`
  validate/nightly job with both UBSan/ASan enabled. This is enabled in
  full-ci pipelines as well as MR pipelines with `test-sanitizer` label.
  

• 913a7f30
  by Cheng Shao at 2026-07-20T10:57:50+02:00

  rts: add ASAN instrumentation to mblock allocator
  

• 5b706f91
  by Cheng Shao at 2026-07-20T10:57:50+02:00

  rts: add ASAN instrumentation to mgroup allocator
  

• 00c1e2ac
  by Cheng Shao at 2026-07-20T10:57:50+02:00

  rts: add ASAN instrumentation to block allocator
  

• 235ac124
  by Cheng Shao at 2026-07-20T10:57:50+02:00

  rts: add ASAN instrumentation to cap->pinned_object_empty
  

• c1652078
  by Cheng Shao at 2026-07-20T10:57:50+02:00

  rts: add ASAN instrumentation to gc_thread->free_blocks
  

• f2c4ec22
  by Cheng Shao at 2026-07-20T10:57:50+02:00

  rts: add ASAN instrumentation to hash table free list
  

• 8dcef1db
  by Cheng Shao at 2026-07-20T10:57:50+02:00

  rts: add ASAN instrumentation to per-Task InCall free list
  

• c0ed3299
  by Cheng Shao at 2026-07-20T10:57:50+02:00

  rts: add ASAN instrumentation to nonmoving allocator
  

364 changed files:

• .gitignore
• .gitlab-ci.yml
• .gitlab/ci.sh
• .gitlab/generate-ci/gen_ci.hs
• .gitlab/jobs.yaml
• .gitlab/merge_request_templates/Default.md
• .gitlab/rel_eng/mk-ghcup-metadata/mk_ghcup_metadata.py
• + changelog.d/T21628
• + changelog.d/T26532
• + changelog.d/T27123.md
• + changelog.d/T27314.md
• + changelog.d/T27329
• + changelog.d/T27360
• + changelog.d/T27374
• + changelog.d/T27456
• + changelog.d/fix-absent-dict-projection
• + changelog.d/fix-cmm-atomic-load-store
• + changelog.d/fix-make-install-j
• + changelog.d/fix-peekitbl-no-tntc
• + changelog.d/fix-use-std-ap-thunk
• + changelog.d/inter-module-far-jumps-aarch64-default
• compiler/GHC/Builtin/Types/Prim.hs
• compiler/GHC/Builtin/Utils.hs
• compiler/GHC/ByteCode/Breakpoints.hs
• compiler/GHC/ByteCode/Types.hs
• compiler/GHC/Cmm/CLabel.hs
• compiler/GHC/Cmm/Parser.y
• compiler/GHC/Core/Coercion/Opt.hs
• compiler/GHC/Core/Make.hs
• compiler/GHC/Core/Opt/Specialise.hs
• compiler/GHC/Core/Opt/WorkWrap.hs
• compiler/GHC/Core/Opt/WorkWrap/Utils.hs
• compiler/GHC/Core/Ppr.hs
• compiler/GHC/Core/TyCo/Ppr.hs
• compiler/GHC/Core/TyCo/Rep.hs
• compiler/GHC/Core/TyCon.hs
• compiler/GHC/CoreToStg/Prep.hs
• compiler/GHC/Data/FastString.hs
• compiler/GHC/Data/StringBuffer.hs
• compiler/GHC/Driver/Backend.hs
• compiler/GHC/Driver/CodeOutput.hs
• compiler/GHC/Driver/Config/StgToCmm.hs
• compiler/GHC/Driver/DynFlags.hs
• compiler/GHC/Driver/Errors/Ppr.hs
• compiler/GHC/Driver/Flags.hs
• compiler/GHC/Driver/Main/Compile.hs
• compiler/GHC/Driver/Main/Hsc.hs
• compiler/GHC/Driver/Main/Passes.hs
• compiler/GHC/Driver/Pipeline.hs
• compiler/GHC/Driver/Session.hs
• compiler/GHC/Hs/Binds.hs
• compiler/GHC/Hs/Decls.hs
• compiler/GHC/Hs/Dump.hs
• compiler/GHC/Hs/Expr.hs
• compiler/GHC/Hs/Instances.hs
• compiler/GHC/Hs/Lit.hs
• compiler/GHC/Hs/Type.hs
• compiler/GHC/Hs/Utils.hs
• compiler/GHC/HsToCore.hs
• compiler/GHC/HsToCore/Breakpoints.hs
• + compiler/GHC/HsToCore/Breakpoints/Types.hs
• compiler/GHC/HsToCore/Errors/Types.hs
• compiler/GHC/HsToCore/Expr.hs
• compiler/GHC/HsToCore/Foreign/C.hs
• compiler/GHC/HsToCore/Foreign/JavaScript.hs
• compiler/GHC/HsToCore/Foreign/Wasm.hs
• compiler/GHC/HsToCore/Match.hs
• compiler/GHC/HsToCore/Match/Literal.hs
• compiler/GHC/HsToCore/Pmc/Desugar.hs
• compiler/GHC/HsToCore/Pmc/Solver.hs
• compiler/GHC/HsToCore/Pmc/Solver/Types.hs
• compiler/GHC/HsToCore/Quote.hs
• compiler/GHC/HsToCore/Ticks.hs
• compiler/GHC/Iface/Ext/Ast.hs
• compiler/GHC/Iface/Load.hs
• compiler/GHC/Iface/Make.hs
• compiler/GHC/Iface/Recomp.hs
• compiler/GHC/Iface/Syntax.hs
• compiler/GHC/Parser.y
• compiler/GHC/Parser/Annotation.hs
• compiler/GHC/Parser/Errors/Ppr.hs
• compiler/GHC/Parser/HaddockLex.x
• compiler/GHC/Parser/Lexer.x
• compiler/GHC/Parser/PostProcess.hs
• compiler/GHC/Platform/Ways.hs
• compiler/GHC/Rename/Bind.hs
• compiler/GHC/Rename/Env.hs
• compiler/GHC/Rename/Expr.hs
• compiler/GHC/Rename/HsType.hs
• compiler/GHC/Rename/Module.hs
• compiler/GHC/Rename/Names.hs
• compiler/GHC/Rename/Splice.hs
• compiler/GHC/Rename/Utils.hs
• compiler/GHC/Runtime/Eval.hs
• compiler/GHC/StgToByteCode.hs
• compiler/GHC/StgToCmm/Bind.hs
• compiler/GHC/StgToCmm/Config.hs
• compiler/GHC/StgToCmm/Foreign.hs
• compiler/GHC/StgToCmm/Prim.hs
• compiler/GHC/StgToJS/FFI.hs
• compiler/GHC/Tc/Deriv.hs
• compiler/GHC/Tc/Deriv/Generate.hs
• compiler/GHC/Tc/Deriv/Generics.hs
• compiler/GHC/Tc/Errors.hs
• compiler/GHC/Tc/Errors/Ppr.hs
• compiler/GHC/Tc/Errors/Types.hs
• compiler/GHC/Tc/Gen/Bind.hs
• compiler/GHC/Tc/Gen/Expr.hs
• compiler/GHC/Tc/Gen/Head.hs
• compiler/GHC/Tc/Gen/HsType.hs
• compiler/GHC/Tc/Gen/Pat.hs
• compiler/GHC/Tc/Gen/Sig.hs
• compiler/GHC/Tc/Gen/Splice.hs
• compiler/GHC/Tc/Instance/Class.hs
• compiler/GHC/Tc/Instance/Typeable.hs
• compiler/GHC/Tc/Solver/Dict.hs
• compiler/GHC/Tc/TyCl.hs
• compiler/GHC/Tc/TyCl/Utils.hs
• compiler/GHC/Tc/Types/Origin.hs
• compiler/GHC/Tc/Types/Rank.hs
• compiler/GHC/Tc/Validity.hs
• compiler/GHC/ThToHs.hs
• compiler/GHC/Types/Basic.hs
• compiler/GHC/Types/Error.hs
• compiler/GHC/Types/FieldLabel.hs
• compiler/GHC/Types/ForeignCall.hs
• compiler/GHC/Types/Literal.hs
• compiler/GHC/Unit/Module/ModGuts.hs
• compiler/GHC/Unit/Module/ModIface.hs
• compiler/GHC/Unit/Module/Warnings.hs
• compiler/GHC/Unit/Module/WholeCoreBindings.hs
• compiler/GHC/Utils/Binary.hs
• compiler/GHC/Utils/Outputable.hs
• compiler/Language/Haskell/Syntax/Basic.hs
• compiler/Language/Haskell/Syntax/Binds.hs
• compiler/Language/Haskell/Syntax/Decls.hs
• compiler/Language/Haskell/Syntax/Decls/Foreign.hs
• compiler/Language/Haskell/Syntax/Expr.hs
• compiler/Language/Haskell/Syntax/Extension.hs
• compiler/Language/Haskell/Syntax/Lit.hs
• compiler/Language/Haskell/Syntax/Module/Name.hs
• + compiler/Language/Haskell/Syntax/Text.hs
• compiler/Language/Haskell/Syntax/Type.hs
• compiler/ghc.cabal.in
• docs/users_guide/expected-undocumented-flags.txt
• docs/users_guide/exts/rank_polymorphism.rst
• docs/users_guide/exts/static_pointers.rst
• docs/users_guide/using-optimisation.rst
• ghc/GHCi/UI.hs
• hadrian/bindist/Makefile
• hadrian/cabal.project
• hadrian/doc/flavours.md
• hadrian/src/Flavour.hs
• hadrian/src/Rules.hs
• hadrian/src/Rules/BinaryDist.hs
• libraries/base/changelog.md
• libraries/base/src/System/Environment.hs
• libraries/base/tests/T15349.stderr
• libraries/ghc-boot/GHC/Data/ShortText.hs
• + libraries/ghc-heap/tests/T27465.hs
• + libraries/ghc-heap/tests/T27465.stdout
• libraries/ghc-heap/tests/all.T
• libraries/ghc-internal/ghc-internal.cabal.in
• libraries/ghc-internal/src/GHC/Internal/Event/Control.hs
• libraries/ghc-internal/src/GHC/Internal/Event/Manager.hs
• libraries/ghc-internal/src/GHC/Internal/Event/TimerManager.hs
• libraries/ghc-internal/src/GHC/Internal/Exception/Type.hs
• libraries/ghc-internal/src/GHC/Internal/Heap/InfoTable.hsc
• libraries/ghc-internal/src/GHC/Internal/Heap/InfoTableProf.hsc
• libraries/ghc-internal/src/GHC/Internal/IO/Handle/Lock.hs
• libraries/ghc-internal/tests/backtraces/T14532b.stdout
• nofib
• rts/.ubsan-suppressions
• rts/Apply.cmm
• rts/Capability.c
• rts/Capability.h
• rts/ContinuationOps.cmm
• rts/Hash.c
• rts/IOManager.c
• rts/IOManager.h
• rts/IOManagerInternals.h
• rts/PrimOps.cmm
• rts/RaiseAsync.c
• rts/RtsStartup.c
• rts/RtsSymbols.c
• rts/Schedule.c
• rts/Schedule.h
• rts/Task.c
• rts/include/Stg.h
• + rts/include/rts/ASANUtils.h
• rts/include/rts/IOInterface.h
• rts/include/rts/storage/Closures.h
• rts/include/rts/storage/TSO.h
• rts/posix/FdWakeup.h
• + rts/posix/MIO.c
• + rts/posix/MIO.h
• rts/posix/Poll.c
• rts/posix/Poll.h
• rts/posix/Select.c
• rts/posix/Select.h
• rts/posix/Signals.c
• rts/posix/Signals.h
• rts/posix/Timeout.c
• rts/posix/Timeout.h
• rts/rts.cabal
• rts/sm/BlockAlloc.c
• rts/sm/GCUtils.c
• rts/sm/MBlock.c
• rts/sm/NonMoving.c
• rts/sm/NonMovingAllocate.c
• rts/sm/NonMovingMark.c
• rts/sm/NonMovingSweep.c
• rts/sm/Storage.c
• rts/win32/AsyncMIO.c
• rts/win32/AsyncMIO.h
• rts/win32/AsyncWinIO.h
• rts/win32/AwaitEvent.c
• rts/win32/AwaitEvent.h
• rts/win32/ConsoleHandler.h
• rts/win32/MIOManager.h
• rts/win32/ThrIOManager.h
• rts/win32/WorkQueue.h
• rts/win32/veh_excn.h
• testsuite/driver/junit.py
• testsuite/driver/perf_notes.py
• testsuite/driver/testglobals.py
• testsuite/driver/testlib.py
• testsuite/driver/testutil.py
• testsuite/tests/backpack/should_compile/T13149.bkp
• testsuite/tests/cmm/should_run/AtomicFetch.hs
• testsuite/tests/cmm/should_run/AtomicFetch_cmm.cmm
• testsuite/tests/codeGen/should_compile/T25177.stderr
• testsuite/tests/codeGen/should_run/cgrun025.stderr
• + testsuite/tests/core-to-stg/T25924/B.hs
• + testsuite/tests/core-to-stg/T25924/Main.hs
• + testsuite/tests/core-to-stg/T25924/all.T
• + testsuite/tests/core-to-stg/T25924a.hs
• + testsuite/tests/core-to-stg/T25924a.stdout
• testsuite/tests/core-to-stg/all.T
• + testsuite/tests/corelint/T27374.hs
• testsuite/tests/corelint/all.T
• testsuite/tests/count-deps/CountDepsAst.stdout
• testsuite/tests/count-deps/CountDepsParser.stdout
• testsuite/tests/deSugar/should_fail/all.T
• testsuite/tests/determinism/determ017/A.hs
• testsuite/tests/dmdanal/should_compile/T18982.stderr
• testsuite/tests/exceptions/T26759.stderr
• testsuite/tests/ffi/should_run/all.T
• testsuite/tests/ghc-api/T25121_status.stdout
• testsuite/tests/ghc-api/annotations-literals/parsed.hs
• testsuite/tests/ghc-api/exactprint/T22919.stderr
• testsuite/tests/ghc-api/exactprint/Test20239.stderr
• testsuite/tests/ghc-api/exactprint/ZeroWidthSemi.stderr
• testsuite/tests/ghc-e/should_fail/T18441fail7.stderr
• testsuite/tests/ghci/scripts/T12005.script
• testsuite/tests/ghci/scripts/all.T
• + testsuite/tests/ghci/scripts/bytecodeIPE.hs
• + testsuite/tests/ghci/scripts/bytecodeIPE.script
• + testsuite/tests/ghci/scripts/bytecodeIPE.stdout
• testsuite/tests/ghci/should_run/Makefile
• + testsuite/tests/ghci/should_run/T27287.hs
• + testsuite/tests/ghci/should_run/T27287.stdout
• testsuite/tests/ghci/should_run/all.T
• testsuite/tests/haddock/perf/Fold.hs
• testsuite/tests/haddock/should_compile_flag_haddock/T17544.stderr
• testsuite/tests/haddock/should_compile_flag_haddock/T17544_kw.stderr
• testsuite/tests/haddock/should_compile_flag_haddock/T24221.stderr
• testsuite/tests/indexed-types/should_fail/T7354.hs
• testsuite/tests/interface-stability/base-exports.stdout
• testsuite/tests/interface-stability/base-exports.stdout-javascript-unknown-ghcjs
• testsuite/tests/interface-stability/base-exports.stdout-mingw32
• testsuite/tests/layout/layout001.stdout
• testsuite/tests/layout/layout002.stdout
• testsuite/tests/layout/layout003.stdout
• testsuite/tests/layout/layout004.stdout
• testsuite/tests/layout/layout005.stdout
• testsuite/tests/layout/layout006.stdout
• testsuite/tests/layout/layout007.stdout
• testsuite/tests/layout/layout008.stdout
• testsuite/tests/layout/layout009.stdout
• testsuite/tests/linear/should_compile/T1735Min.hs
• testsuite/tests/mdo/should_fail/mdofail006.stderr
• testsuite/tests/module/mod185.stderr
• testsuite/tests/numeric/should_compile/T15547.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/DumpTypecheckedAst.stderr
• testsuite/tests/parser/should_compile/KindSigs.stderr
• + testsuite/tests/parser/should_compile/T13087.stderr
• testsuite/tests/parser/should_compile/T14189.stderr
• testsuite/tests/parser/should_compile/T15323.stderr
• testsuite/tests/parser/should_compile/T20452.stderr
• testsuite/tests/parser/should_compile/T20718.stderr
• testsuite/tests/parser/should_compile/T20718b.stderr
• testsuite/tests/parser/should_compile/T20846.stderr
• testsuite/tests/parser/should_compile/T23315/T23315.stderr
• testsuite/tests/parser/should_fail/T8431.stderr
• testsuite/tests/parser/should_fail/readFail038.stderr
• + testsuite/tests/parser/should_run/StringStartsWithNull.hs
• + testsuite/tests/parser/should_run/StringStartsWithNull.stdout
• testsuite/tests/parser/should_run/all.T
• testsuite/tests/perf/compiler/T3064.hs
• testsuite/tests/perf/compiler/hard_hole_fits.stderr
• + testsuite/tests/pmcheck/should_compile/T27314.hs
• + testsuite/tests/pmcheck/should_compile/T27360.hs
• testsuite/tests/pmcheck/should_compile/all.T
• testsuite/tests/polykinds/T7594.hs
• testsuite/tests/printer/AnnotationNoListTuplePuns.stdout
• testsuite/tests/printer/T18791.stderr
• testsuite/tests/printer/Test20297.stdout
• testsuite/tests/printer/Test24533.stdout
• testsuite/tests/programs/thurston-modular-arith/Main.hs
• testsuite/tests/rts/T18623/all.T
• + testsuite/tests/rts/T27123.hs
• testsuite/tests/rts/all.T
• testsuite/tests/rts/ipe/IpeStats/Fold.hs
• testsuite/tests/runghc/T7859.stderr-mingw32
• testsuite/tests/simplCore/should_compile/DataToTagFamilyScrut.stderr
• testsuite/tests/simplCore/should_compile/T11562.hs
• testsuite/tests/simplCore/should_compile/T14978.stdout
• testsuite/tests/simplCore/should_compile/T18013.stderr
• testsuite/tests/simplCore/should_compile/T24229a.stderr
• testsuite/tests/simplCore/should_compile/T24229b.stderr
• testsuite/tests/simplCore/should_compile/T26615.stderr
• testsuite/tests/simplCore/should_run/T3591.hs
• testsuite/tests/typecheck/should_compile/DeepSubsumption02.hs
• testsuite/tests/typecheck/should_compile/T12507.hs
• testsuite/tests/typecheck/should_compile/T13951.hs
• testsuite/tests/typecheck/should_compile/T15242.stderr
• testsuite/tests/typecheck/should_compile/T18920.hs
• testsuite/tests/typecheck/should_compile/T2595.hs
• testsuite/tests/typecheck/should_compile/T7541.hs
• testsuite/tests/typecheck/should_compile/all.T
• testsuite/tests/typecheck/should_fail/T15067.stderr
• + testsuite/tests/typecheck/should_fail/T26532.hs
• + testsuite/tests/typecheck/should_fail/T26532.stderr
• testsuite/tests/typecheck/should_fail/T6069.stderr
• testsuite/tests/typecheck/should_fail/T7368a.hs
• testsuite/tests/typecheck/should_fail/T9858b.stderr
• testsuite/tests/typecheck/should_fail/TcStaticPointersFail02.stderr
• testsuite/tests/typecheck/should_fail/all.T
• testsuite/tests/typecheck/should_run/T1735_Help/Basics.hs
• testsuite/tests/typecheck/should_run/T3731-short.hs
• testsuite/tests/typecheck/should_run/T3731.hs
• testsuite/tests/typecheck/should_run/church.hs
• testsuite/tests/typecheck/should_run/tcrun008.hs
• testsuite/tests/typecheck/should_run/tcrun017.hs
• testsuite/tests/typecheck/should_run/tcrun026.hs
• testsuite/tests/typecheck/should_run/tcrun035.hs
• testsuite/tests/typecheck/should_run/tcrun036.hs
• utils/check-exact/ExactPrint.hs
• utils/check-exact/Main.hs
• utils/check-exact/Transform.hs
• utils/check-exact/Utils.hs
• utils/check-exact/check-exact.cabal
• utils/deriveConstants/Main.hs
• utils/haddock/haddock-api/haddock-api.cabal
• utils/haddock/haddock-api/src/Haddock/Backends/Hyperlinker/Parser.hs
• utils/haddock/haddock-api/src/Haddock/Backends/LaTeX.hs
• utils/haddock/haddock-api/src/Haddock/Backends/Xhtml/Decl.hs
• utils/haddock/haddock-api/src/Haddock/Convert.hs
• utils/haddock/haddock-api/src/Haddock/Interface/Create.hs

The diff was not included because it is too large.