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

Commits:

9284a1f7

by Simon Hengel at 2026-06-23T05:55:33-04:00

Don't use global variables to address concurrency bugs! (fixes #27234)

This was originally introduce with
88f38b03025386f0f1e8f5861eed67d80495168a to address #17922.

In this specific case a better fix would have been to synchronize on
stderr:

    withHandle_ "stderrSupportsAnsiColors" stderr $ \ _ -> do
      ...

But apparently the dependency on `terminfo` was removed in
32ab07bf3d6ce45e8ea5b55e8095174a6b42a7f0, preventing #17922 in the first
place.

44309cd3

by Alan Zimmerman at 2026-06-23T05:56:20-04:00

EPA: remove LocatedL / SrcSpanAnnL and  LocatedLI / SrcSpanAnnLI

This is part of a refactor towards only having LocatedA / SrcSpanAnnA

It removes the stated items, but has to add back one for BooleanFormula,
LocatedBF / SrcSpanAnnBF

This commit also use the HsConDetails RecCon extension point to
capture the braces in a record constructor

2f6a5534

by Simon Jakobi at 2026-06-23T15:46:20+02:00

Add -dstable-core-dump-order for stable Core dump ordering (#27296)

The order of top-level bindings in Core dumps (-ddump-simpl etc.) is the
compiler's Unique-sensitive internal processing order, so an unrelated
upstream change can reorder them and defeat a textual diff of two dumps.

This adds an opt-in flag -dstable-core-dump-order that reorders the
top-level bindings of dumps routed through dumpPassResult into a stable,
Unique-independent order, so two dumps line up across rebuilds. See
Note [Stable Core dump order] in GHC.Core.Ppr for the sort key and its
rationale.

Adds tests T27296 (binders GHC emits in non-source order by default,
asserted to come out stably ordered under the flag) and T27296b (an
untidied -ddump-float-out dump pinning the ordering of the anonymous lvl
floats by literal value).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

141986e3

by mangoiv at 2026-06-24T15:51:14-04:00

compiler: refactor error reporting code for ExplicitLevelImports

Refactors error reporting code for ExplicitLevelImports to pass in a
RdrName and a GlobalReaderElt to be able to report errors that are
faithful to the source and to more precisely distinguish between names
that are in scope from different qualifications.

Fixes #27385 and #26616

aa7df6b6

by Simon Hengel at 2026-06-24T15:52:18-04:00

Set GHC_VERSION when calling custom pre-processors (see #25952)

(so that pre-processors can emit backwards compatible code)

a9e494f2

by Simon Hengel at 2026-06-24T15:54:08-04:00

Add a flag to control GHCi specific error hints (close #27409)

a805b2a2

by Simon Hengel at 2026-06-24T15:55:20-04:00

Reference correct package in error messages for reexported modules

(fixes #27417)

f235d183

by Simon Jakobi at 2026-06-25T05:51:18-04:00

Add explicit setBit/clearBit/complementBit for instance Bits Integer (#21176)

The default setBit, clearBit, and complementBit methods allocate
intermediate Integers per call. Define them explicitly via the new
integerSetBit[#], integerClearBit[#] and integerComplementBit[#], built
on the BigNat# primitives, which avoid those allocations. Allocation is not
eliminated entirely -- the negative (IN) cases would need in-place mutation,
which is left as future work.

The default methods constant-folded on literal arguments via the
integerOr/integerAnd/integerXor rules, which fold literal Integers of any
size. The explicit functions have no such rule, so they (their Word-argument
wrappers, and the Bits Integer methods) are marked INLINE to expose the
underlying primops to the simplifier; see Note [INLINE for constant folding
of bit operations]. This restores folding only on the small-int (IS) path --
large literal Integers (IP/IN) are no longer constant-folded, a minor
regression for that case. T8832 covers the IS-path folding.

The new golden-output test T21176 checks all three operations against the
default implementations across the sign/size boundaries, recording each
result plus its integerCheck validity. The base and ghc-bignum interface-
stability export goldens gain the new functions.

The main changelog entry lives in changelog.d under a new ghc-internal
section (renamed from ghc-prim).

CLC proposal: https://github.com/haskell/core-libraries-committee/issues/423

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

202ed264

by Marc Scholten at 2026-06-25T05:52:21-04:00

haddock: use Text in documentation pipeline

This patch moves Haddock's documentation pipeline from String to Text
where the data is already textual. It avoids repeated conversions while
keeping the existing decoding behavior for invalid UTF-8 docstring
chunks.

The main changes are:

* Render and carry docstrings as Text in Haddock-facing paths.
* Use the Binary Text instance from GHC.Utils.Binary for Haddock
  interface files, and bump the Haddock binary interface version.
* Add a FastString HTML instance so XHTML rendering avoids
  intermediate String allocation.
* Keep HsDocStringChunk decoding lenient, matching the previous
  unpackHDSC behavior on invalid UTF-8 input.
* Update the xhtml submodule to 3000.4.1.0, which contains the
  apostrophe escaping fix used by the Haddock test output.

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
Assisted-by: Codex <codex@openai.com>

a72ff58f

by mangoiv at 2026-06-25T05:53:07-04:00

compiler: rename ZonkAny to UnusedType and add pretty printing logic

ZonkAny is a hard to understand name for users who do not know how the
compiler works internally. Additionally, it is confusing that ZonkAny,
while being a concrete type *represents* a meta variable, espeically in
the compiler output.
This patch changes the name of ZonkAny to UnusedType which is closer to
its intended semantics and adds special pretty printing logic to display
this type in the same fashion the compiler displays meta variables in
other places, whenever they leak from the implementation to the user.
It also exports the type from ghc-internal:GHC.Internal.Types in order
to expose documentation.

Fixes #27390

Co-Authored-By: Sam Derbyshire <sam.derbyshire@gmail.com>

6813f002

by Simon Jakobi at 2026-06-26T04:51:47-04:00

Reg.Linear: drop Platform argument from most FR (FreeRegs) methods

The FR class has one instance per CPU architecture, so any
architecture-constant information its methods derived from the Platform
argument can instead be baked into the instance. This removes the now
needless Platform argument from frAllocateReg, frGetFreeRegs and
frReleaseReg.

frInitFreeRegs keeps its Platform argument: the initial allocatable set is
genuinely platform-dependent, see Note [Aarch64 Register x18 at Darwin and
Windows].

Fixes #26665

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

3b2a9409

by Zubin Duggal at 2026-06-26T04:52:39-04:00

testsuite: Report fragile failures as skipped in JUnit output

27463426

by Rodrigo Mesquita at 2026-06-26T20:54:58-04:00

perf: Share Module in Iface Symbol Table

This commit modifies the structure of the serialized `SymbolTable Name`
to then re-use and share the `Module` (both on disk and in memory) across
all `Name`s from the same module.

The new structure looks like:

  <total name count>
  $modules.size
  for (mod, names) in $modules:
    $mod
    $names.size
    for table_ix, occ in $names
      $table_ix
      $occ

i.e. we put the module just once, followed by all names in that module.
When deserializing, we deserialize the module just once, and all the
following `Name`s are constructed with a pointer to that same decoded
`Module`.

In `hoogle-test`, we must use `DNameEnv` rather than `Map Name`,
otherwise the output fixities order was susceptible to changes in the
uniques assigned to each Names, which is not stable.

Fixes #27401

-------------------------
Metric Decrease:
    InstanceMatching
    LinkableUsage01
    LinkableUsage02
    hard_hole_fits
-------------------------

412f1675

by Simon Hengel at 2026-06-26T20:55:41-04:00

Rename `MCDiagnostic` to `InternalMCDiagnostic`

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

Any code that creates `MCDiagnostic` directly, without going through
`GHC.Driver.Errors.printMessage`, sidesteps `-fdiagnostics-as-json` (see
e.g. !14616, !14475, !14492 !14548).

To avoid this in the future, this change more narrowly controls who
creates `MCDiagnostic` (see #24113).

6f212121
by Facundo Domínguez at 2026-06-26T20:56:27-04:00
```
Encapsulate options of occurAnalysePgm in a record
```

adfbb179

by Facundo Domínguez at 2026-06-26T20:56:27-04:00

Allow to configure the occurrence analyser to retain some dead bindings

This is needed by plugins that are the only consumers of a binding which
is otherwise unused in the program.

See Note [Controlling elimination of dead bindings in occurrence analysis]
added in this commit, or
https://gitlab.haskell.org/ghc/ghc/-/issues/27240 for more discussion.

c745b11f
by Copilot at 2026-06-26T20:56:27-04:00
```
Address documentation feedback
```

2c2a4a2a

by Copilot at 2026-06-26T20:56:27-04:00

Keep the imp_rules parameter of occurPgmAnalysePgm and add occ_opts to OccEnv

e2262b0e

by Copilot at 2026-06-26T20:56:27-04:00

Strengthen T27240.hs with a binding that should be removed

5f9d9268

by Copilot at 2026-06-26T20:56:27-04:00

Move the reference #27240 to a related paragraph

d86d2644

by Simon Hengel at 2026-06-26T20:57:10-04:00

Remove deprecated flag `-ddump-json` (see #24113)

This was first deprecated in 9.10.1.

3b15ff03

by Simon Jakobi at 2026-06-27T18:48:34+02:00

Tweak mk_mod_usage_info

* Use O(log n) `elemModuleEnv` instead of O(n) `elem` to filter the
  direct imports.
* Use `nonDetModuleEnvKeys` to avoid sorting the ent_map keys twice.
* Prepend the presumably shorter list when creating all_mods with
  `(++)`. Actually this eliminates the `(++)` entirely, as it seems to
  fuse with the `filter` expression.

As a result there is a tiny speed-up when generating the .hi-files for
modules with many imports.

None of the changes affect compilation determinism as the module list
is explicitly sorted to ensure a canonical order.

2d0fd154

by Alan Zimmerman at 2026-06-29T11:44:00-04:00

EPA: Remove LocatedC / SrcSpanAnnC

This is part of a cleanup of the zoo of
SrcSpanAnnXXX types for exact print annotations.

This one removes SrcSpanAnnC used for storing exact print annotations
for contexts. It replaces it with an explicit `HsContext` data type
that carries the annotations and the context.

So, replace

  type HsContext pass = [LHsType pass]

with

  type HsContext pass = HsContextDetails pass (LHsType pass)

  data HsContextDetails pass arg
    = HsContext
      { hsc_ext  :: !(XHsContext pass)
      , hsc_ctxt :: [arg]
      }
    | XHsContextDetails !(XXHsContextDetails pass)

We need the parameterised HsContextDetails because it is used both for
HsQual carrying 'LHsExpr p' and "normal" contexts carrying 'LHsType p'.

cca0d589

by Luite Stegeman at 2026-06-30T13:33:40-04:00

rts: handle large AP 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  24

Closure type 24 is the AP closure, which was not handled in
upd_fwd_large. This patch adds handling them.

fixes #27434

42935858

by Luite Stegeman at 2026-06-30T13:33:40-04:00

testsuite: use compacting_gc way instead of hardcoding +RTS -c

bf7b5ce6

by Alan Zimmerman at 2026-06-30T13:34:23-04:00

EPA: Remove LocatedLW from LStmtLR

HsDo already had its XDo extension point for an
AnnList, which also appeared in LocatedLW.
So we remove the redundant one and use the one inside HsDo
as originally intended.

Also delete LocatedLC/LocatedLS as they were unused

d7cfea49

by Recursion Ninja at 2026-06-30T21:37:12-04:00

Decoupling 'L.H.S' from 'GHC.Types.SourceText'

  * Migrated 'IntegralLit'   to 'L.H.S.Lit'.
  * Migrated 'FractionalLit' to 'L.H.S.Lit'.
  * Migrated 'StringLiteral' to 'L.H.S.Lit'.
  * Added TTG extension points to the types above.
  * Added nice export list to 'GHC.Hs.Lit'.
  * Added 'rnOverLitVal' and 'tcOverLitVal' functions to 'GHC.Hs.Lit'.
  * Added instance 'Anno (StringLiteral (GhcPass p)) = SrcSpanAnnN'
  * Moved [Notes] about 'SourceText' from 'L.H.S.*' to 'GHC.*'.
  * Removed all references to 'SourceText' from 'L.H.S'.
  * Removed the trailing comma record field from  'StringLiteral'
  * Renamed exported functions for nomenclature consistency.
  * Deprecated the renamed functions

Fixes #26953

a1f2558b

by Recursion Ninja at 2026-06-30T21:37:12-04:00

Monomorphising GHC pass parameters where appropriate

7bf9e3c5

by Teo Camarasu at 2026-06-30T21:38:03-04:00

Make Q abstract

This patch aims to clearly demarcate the internal and external interfaces
of Q.
In the past the `Quasi` typeclass was both part of the external,
public-facing interface, and was used to give the implementation of `Q`.

Now we separate out these two distinct roles. `Quasi` continues to exist
in the public interface, but we introduce a new `MetaHandlers` type,
which is equivalent to `Dict Quasi`.

`Q a` is now defined to be `MetaHandlers -> IO a`, and, crucially,
the constructor and the new `MetaHandlers` type are not exposed from the
public interface.

This gives us the ability to vary the interface on the GHC side without
forcing a breaking change on the `template-haskell` side.
Similarly `template-haskell` has more freedom to change the `Quasi`
typeclass without needing any changes in `lib:ghc`.

Implements https://github.com/ghc-proposals/ghc-proposals/pull/700

Resolves #27341

4262af36

by L0neGamer at 2026-06-30T21:38:56-04:00

generically defines mconcat in terms of internal type's Semigroup instance

add changelog entry

use simpler definition for mconcat

`nonEmpty` isn't available yet; inline branches in case

add test case

fixup generically defines mconcat in terms of internal type's Semigroup instance

add comment on Generically and deriving mishaps

swap mconcat to foldr version

add some strictness testing for mconcat

add to `base` changelog entry

e22ad997

by Cheng Shao at 2026-06-30T21:39:43-04:00

hadrian/rts: fix unregisterised build for gcc 15+

This patch fixes unregisterised build for gcc 15+:

- Pass -optc-Wno-error in hadrian when +werror enables -optc-Werror,
  see added comment for details.
- For RTS functions that the codegen would emit calls, ensure their
  real prototype is hidden when the header is included in .hc fies
  (IN_STG_CODE), and the dummy prototype is provided to match the EFF_
  convention.

In the future we should get rid of EFF_ (#14647) and remove these
hacks, but for now this patch makes unregisterised work again on newer
toolchains. Fixes #27404.

Co-authored-by: Codex <codex@openai.com>

3f00f234

by Cheng Shao at 2026-06-30T21:40:32-04:00

compiler: fix missing handling of CmmUnsafeForeignCall node in LayoutStack

This patch fixes missing handling of `CmmUnsafeForeignCall` middle
node in the `LayoutStack` pass.

Before proc-points splitting, this pass computes liveliness of local
registers, and spills those alive across a Cmm native call onto the
stack. It need to traverse all middle nodes in each block and check
whether a local register is an assignee, if so then the previous
mapping in `sm_regs` is invalidated and needs to be dropped. However,
it didn't handle `CmmUnsafeForeignCall` node which may also assign to
a local register. When proc-points splitting is enabled, this can
produce an invalid basic block that doesn't properly backup the
updated local register to the stack before doing a Cmm call, resulting
in completely invalid runtime behavior.

The patch also adds a `T27447` regression test. With no-TNTC or with
LLVM backend, without the fix the test case would output a stale
0x1111111111111111 value, instead of the expected 0x2222222222222222
output.

Fixes #27447.

Co-authored-by: Codex <codex@openai.com>

dc9d0dec