GitLab

David Eichmann pushed to branch wip/27162/hadrian-linkhs-response-file at Glasgow Haskell Compiler / GHC

Commits:

404b71c1

by Luite Stegeman at 2026-03-27T04:40:49-04:00

Fix assert in Interpreter.c

If we skip exactly the number of words on the stack we end up on
the first word in the next chunk.

a85bd503

by Luite Stegeman at 2026-03-27T04:40:49-04:00

Support arbitrary size unboxed tuples in bytecode

This stores the size (number of words on the stack) of the next
expected tuple in the TSO, ctoi_spill_size field, eliminating
the need of stg_ctoi_tN frames for each size.

Note: On 32 bit platform there is still a bytecode tuple size
limit of 255 words on the stack.

Fixes #26946

e2209031

by Luite Stegeman at 2026-03-27T04:40:49-04:00

Add specialized frames for small tuples

Small tuples are now returned more efficiently to the interpreter.
They use one less word of stack space and don't need manipulation
of the TSO anymore.

b26bb2ea

by VeryMilkyJoe at 2026-03-27T04:41:38-04:00

Remove backwards compatibility pattern synonym `ModLocation`

Fixes #24932

66e5e324

by Vladislav Zavialov at 2026-03-27T04:42:25-04:00

Extend HsExpr with the StarIsType syntax (#26587, #26967)

This patch allows kinds of the form `k -> *` and `* -> k` to occur in
expression syntax, i.e. to be used as required type arguments.

For example:

	{-# LANGUAGE RequiredTypeArguments, StarIsType #-}
	x1 = f (* -> * -> *)
	x2 = f (forall k. k -> *)
	x3 = f ((* -> *) -> Constraint)

Summary of the changes:

* Introduce the HsStar constructor of HsExpr and its extension field XStar.
  It is analogous to HsStarTy in HsType.

* Refactor HsStarTy to store the unicode flag as TokStar, defined as
    type TokStar = EpUniToken "*" "★"  -- similar to TokForall, TokRArrow, etc.
  The token is stored in the extension field and replaces the Bool field.

* Extend the `infixexp2` nonterminal to parse `*` as a direct argument of `->`.
  This is more limited than the full StarIsType syntax, but has the nice
  property of not conflicting with the multiplication operator `a * b`.

Test case: T26967 T26967_tyop

f8de456f

by Sylvain Henry at 2026-03-27T04:43:22-04:00

STM: don't create a transaction in the rhs of catchRetry# (#26028)

We don't need to create a transaction for the rhs of (catchRetry#)
because contrary to the lhs we don't need to abort it on retry. Moreover
it is particularly harmful if we have code such as (#26028):

  let cN = readTVar vN >> retry
      tree = c1 `orElse` (c2 `orElse` (c3 `orElse` ...))
  atomically tree

Because it will stack transactions for the rhss and the read-sets of all
the transactions will be iteratively merged in O(n^2) after the
execution of the most nested retry.

This is the second attempt at implementing this. The first attempt
triggered segfaults (#26291) and has been reverted.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

fcf092dd

by Luite Stegeman at 2026-03-27T04:44:17-04:00

Windows: remove StgAsyncIOResult and fix crash/leaks

In stg_block_async{_void}, a stack slot was reserved for
an StgAsyncIOResult. This slot would be filled by the IO
manager upon completion of the async call.

However, if the blocked thread was interrupted by an async
exception, we would end up in an invalid state:

 - If the blocked computation was never re-entered, the
   StgAsyncIOResult would never be freed.
 - If the blocked computation was re-entered, the thread would
   find an unitialized stack slot for the StgAsyncIOResult,
   leading to a crash reading its fields, or freeing the pointer.

We fix this by removing the StgAsyncIOResult altogether and writing
the result directly to the stack.

Fixes #26341

05094993

by Luite Stegeman at 2026-03-27T04:45:12-04:00

Don't refine DEFAULT alt for unary typeclasses

A non-DEFAULT data alt for a unary typeclass dictionary would
interfere with Unary Class Magic, leading to segfaults.

fixes #27071

4ee260cf

by sheaf at 2026-03-27T04:46:06-04:00

Fix several oversights in hsExprType

This commit fixes several oversights in GHC.Hs.Syn.Type.hsExprType:

  - The 'RecordCon' case was returning the type of the constructor,
    instead of the constructor application. This is fixed by using
    'splitFunTys'.
  - The 'ExplicitTuple' case failed to take into account tuple sections,
    and was also incorrectly handling 1-tuples (e.g. 'Solo') which can
    be constructed using Template Haskell.
  - The 'NegApp' case was returning the type of the negation operator,
    again failing to apply it to the argument. Fixed by using
    'funResultTy'.
  - The 'HsProc' case was computing the result type of the arrow proc
    block, without taking into account the argument type. Fix that by
    adding a new field to 'CmdTopTc' that stores the arrow type, so that
    we can construct the correct result type `arr a b` for
    `proc (pat :: a) -> (cmd :: b)`.
  - The 'ArithSeq' and 'NegApp' cases were failing to take into account
    the result 'HsWrapper', which could e.g. silently drop casts.
    This is fixed by introducing 'syntaxExpr_wrappedFunResTy' which, on
    top of taking the result type, applies the result 'HsWrapper'.

These fixes are validated by the new GHC API test T26910.

Fixes #26910

e97232ce

by Hai at 2026-03-27T04:47:04-04:00

Parser.y: avoid looking at token with QualifiedDo

This changes the behavior of 'hintQualifiedDo' so that the supplied
token is not inspected when the QualifiedDo language extension bit is
set.

9831385b

by Vladislav Zavialov at 2026-03-27T17:22:30-04:00

Infix holes in types (#11107)

This patch introduces several improvements that follow naturally from
refactoring HsOpTy to represent the operator as an HsType, aligning it
with the approach taken by OpApp and HsExpr.

User-facing changes:

1. Infix holes (t1 `_` t2) are now permitted in types, following the
   precedent set by term-level expressions.

   Test case: T11107

2. Error messages for illegal promotion ticks are now reported at more
   precise source locations.

   Test case: T17865

Internal changes:

* The definition of HsOpTy now mirrors that of OpApp:

    | HsOpTy (XOpTy p)  (LHsType p) (LHsType p) (LHsType p)
    | OpApp  (XOpApp p) (LHsExpr p) (LHsExpr p) (LHsExpr p)

  This moves us one step closer to unifying HsType and HsExpr.

* Ignoring locations,
    the old pattern match (HsOpTy x prom lhs op rhs)
    is now written as     (HsOpTy x lhs (HsTyVar x' prom op) rhs)
    but we also handle    (HsOpTy x lhs (HsWildCardTy x')    rhs)

  Constructors other than HsTyVar and HsWildCardTy never appear
  in the operator position.

* The various definitions across the compiler have been updated to work
  with the new representation, drawing inspiration from the term-level
  pipeline where appropriate.  For example,

     ppr_infix_ty       <=> ppr_infix_expr
     get_tyop           <=> get_op
     lookupTypeFixityRn <=> lookupExprFixityRn
           (the latter is factored out from rnExpr)

Test cases: T11107 T17865

5b6757d7

by mangoiv at 2026-03-27T17:23:19-04:00

ci: build i386 non-validate for deb12

This is a small fix that will unlock ghcup metadata to run, i386 debian
12 was missing as a job.

cf942119

by Cheng Shao at 2026-03-30T15:24:37-04:00

ghc-boot: remove unused SizedSeq instances and functions

This commit removes unused `SizedSeq` instances and functions, only
keeping the bits we need for hpc tick sequence for now.

22c5b7cc

by Cheng Shao at 2026-03-30T15:24:38-04:00

ghci: remove unused GHCi.BinaryArray

This patch removes the unused `GHCi.BinaryArray` module from `ghci`.
Closes #27108.

77abb4ab

by Cheng Shao at 2026-03-30T15:25:21-04:00

testsuite: mark T17912 as fragile on Windows

T17912 is still fragile on Windows, it sometimes unexpectedly pass in
CI. This especially strains our already scarce Windows CI runner
resources. Mark it as fragile on Windows for the time being.

d741a6cc

by Andreas Klebinger at 2026-03-31T04:39:33-04:00

Bump minimum shake version for hadrian.

We also add the shake version we want to stack.yaml

Fixes #26884

5e556f9e

by Vladislav Zavialov at 2026-03-31T04:40:16-04:00

Status check for the HsType~HsExpr refactoring (#25121)

Add a test case to track the status of a refactoring project within GHC
whose goal is to arrive at the following declaration:

	type HsType = HsExpr

The rationale for this is to increase code reuse between the term- and
type-level code in the compiler front-end (AST, parser, renamer, type checker).

The status report is saved to testsuite/tests/ghc-api/T25121_status.stdout
and provides useful insights into what needs to happen to make progress on
the ticket.

acffb1b1

by fendor at 2026-03-31T04:41:02-04:00

Extract Binary instances to `GHC.ByteCode.Binary`

e2ea8e25

by fendor at 2026-03-31T04:41:02-04:00

Add `seqNonEmpty` for evaluating `NonEmpty a`

048b00b7

by fendor at 2026-03-31T04:41:02-04:00

Record `LinkableUsage` instead of `Linkable` in `LoaderState`

Retaining a ByteCode `Linkable` after it has been loaded retains its
`UnlinkedBCO`, keeping it alive for the remainder of the program.
This starts accumulating a lot of `UnlinkedBCO` and memory over time.
However, the `Linkable` is merely used to later record its usage in
`mkObjectUsage`, which  is used for recompilation checking.

However, this is incorrect, as the interface file and bytecode objects
could be in different states, e.g. the interface changes, but the
bytecode library hasn't changed so we don't need to recompile and vice
versa.

By computing a `Fingerprint` for the `ModuleByteCode`, and recording it
in the `LinkableUsage`, we know precisely whether the `ByteCode` object
on disk is outdated.

Thus, parts of this commit just makes sure that we efficiently compute a
`Fingerprint` for `ModuleByteCode` and store it in the on-disk
representation of `ModuleByteCode`.

We change the `LoaderState` to retain `LinkableUsage`, which is smaller
representation of a `Linkable`. This allows us to free the unneeded
fields of `Linkable` after linking them.

We declare the following memory invariants that this commit implements:

* No `LinkablePart` should be retained from `LoaderState`.
* `Linkable`s should be unloaded after they have been loaded.

These invariants are unfortunately tricky to automatically uphold, so we
are simply documenting our assumptions for now.

We introduce the `linkable-space` test which makes sure that after
loading, no `DotGBC` or `UnlinkedBCO` is retained.

-------------------------
Metric Increase:
    MultiLayerModulesTH_OneShot
-------------------------

We allocate a bit more, but the peak number of bytes doesn't change.
While a bit unfortunate, accepting the metric increase.

We add multiple new performance measurements where we were able to
observe the desired memory invariants. Further, we add regression tests
to validate that the recompilation checker behaves more correct than
before.

2d1c1997

by Simon Jakobi at 2026-03-31T04:41:46-04:00

Eliminate dictionary-passing in ListMap operations

Mark the ListMap helpers 'INLINABLE' so importing modules can specialise
the 'TrieMap (ListMap m)' methods and avoid recursive dictionary-passing.

See Note [Making ListMap operations specialisable].

Fixes #27097

ed2c6570

by Cheng Shao at 2026-03-31T04:42:33-04:00

testsuite: fix testdir cleanup logic on Windows

testdir cleanup is unreliable on Windows (#13162) and despite existing
hacks in the driver, new failure mode has occurred. This patch makes
it print the warning and carry on when failed to clean up a testdir,
instead of reporting a spurious framework failure. See added comment
for detailed explanation.

d9388e29

by Simon Jakobi at 2026-03-31T13:14:59-04:00

Add regression test for #18177

Closes #18177.

Assisted-by: Codex

6a10045c

by mangoiv at 2026-03-31T13:15:43-04:00

ci: allow metric decrease for two tests on i386

There has been a nightly failure on i386 due to a compiler runtime
improvement on i386 debian 12. We allow that.

Metric Decrease (test_env='i386-linux-deb12'):
  T12707 T8095

7fbb4fcb

by Rodrigo Mesquita at 2026-04-01T12:16:33+00:00

Bump default language edition to GHC2024

As per the accepted ghc-proposal#632

Fixes #26039

5ae43275

by Peng Fan at 2026-04-01T19:01:06-04:00

NCG/LA64: add cmpxchg and xchg primops

And append some new instructions for LA664 uarch.

Apply fix to cmpxchg-prim by Andreas Klebinger.

Suggestions in https://gitlab.haskell.org/ghc/ghc/-/merge_requests/15515

8f95534a

by Duncan Coutts at 2026-04-01T19:01:52-04:00

Remove signal-based ticker implementations

Fixes issue #27073

All supported platforms should work with the pthreads + nanosleep based
ticker implementation. This avoids all the problems with using signals.

In practice, all supported platforms were probably using the non-signal
tickers already, which is probably why we do not get lots of reports
about deadlocks and other weirdness: we were definately using functions
that are not async signal safe in the tick handler (such as fflush to
flussh the eventlog).

Only Solaris was explicitly using the timer_create ticker impl, and even
Solaris could probably use the pthreads one (if anyone cared: Solaris is
no longer a Teir 3 supported platform).

Plausibly the only supported platform that this will change will be AIX,
which should now use the pthreads impl.

51b32b0d
by Duncan Coutts at 2026-04-01T19:01:52-04:00
```
Tidy up some timer/ticker comments elsewhere
```

7562bcd7

by Duncan Coutts at 2026-04-01T19:01:52-04:00

Remove now-unused install_vtalrm_handler

Support function used by both of the signal-based ticker
implementations.

6da127c7

by Duncan Coutts at 2026-04-01T19:01:52-04:00

No longer probe for timer_create in rts/configure

It was only used by the TimerCreate.c ticker impl.

3fd490fa
by Duncan Coutts at 2026-04-01T19:01:53-04:00
```
Note that rtsTimerSignal is deprecated.
```
63099b0f
by Simon Jakobi at 2026-04-01T19:02:39-04:00
```
Add perf test for #13960

Closes #13960.
```

58009c14

by Apoorv Ingle at 2026-04-02T09:51:24+01:00

Streamline expansions using HsExpansion (#25001)

Notes added [Error Context Stack] [Typechecking by expansion: overview]
Notes updated Note [Expanding HsDo with XXExprGhcRn] [tcApp: typechecking applications]

-------------------------
Metric Decrease:
    T9020
-------------------------

There are 2 key changes:

1. `HsExpand` datatype mediates between expansions
2. Replace `ErrCtxtM` to a simpler `HsCtxt` that does not depend on a `TidyEnv`

This has some consequences detailed below:

1. `HsExpand` datatype mediates between expansions
   * Simplifies the implementations of `tcExpr` to work on `XExpr`
   * Removes `VACtxt` (and its associated `VAExpansion` and `VACall`) datatype, it is subsumed by simply a `SrcSpan`.
   * Removes the function `addHeadCtxt` as it is now mearly setting a location
   * The function `tcValArgs` does its own argument number management
   * move `splitHsTypes` out of `tcApp`
   * Removes special case of tcBody from `tcLambdaMatches`
   * Removes special case of `dsExpr` for `ExpandedThingTc`
   * Renames `tcMonoExpr` -> `tcMonoLExpr`, `tcMonoExprNC` -> `tcMonoLExpr`
   * Renames `EValArg`, `EValArgQL` fields: `ea_ctxt` -> `ea_loc_span` and `eaql_ctx` -> `eaql_loc_span`
   * Remove `PopErrCtxt` from `XXExprGhcRn`
   * `fun_orig` in tcInstFun depends on the SrcSpan of the head of the application chain (similar to addArgCtxt)
     - it references the application chain head if it is user located, or
      uses the error context stack  as a fallback if it's a generated
      location
   * Make a new variant `GeneratedSrcSpan` in `SrcSpan` for HIEAst Nodes
    - Expressions wrapped around `GeneratedSrcSpan` are ignored and never added to the error context stack
    - In Explicit list expansion `fromListN` is wrapped with a `GeneratedSrcSpan` with `GeneratedSrcSpanDetails` field to store the original srcspan

2. Replace `ErrCtxtM` to a simpler `HsCtxt` that does not depend on a `TidyEnv`
   * Merge `HsThingRn` to `HsCtxt`
   * Landmark Error messages are now just computed on the fly
   * Make HsExpandedRn and HsExpandedTc payload a located HsExpr GhcRn
   * `HsCtxt` are tidied and zonked at the end right before printing

Co-authored-by: simonpj <simon.peytonjones@gmail.com>

bc4b4487

by Zubin Duggal at 2026-04-03T14:22:27-04:00

driver: recognise .dyn_o as a valid object file to link if passed on the command line.
This allows plugins compiled with this suffix to run.

Fixes #24486

5ebb9121
by Simon Jakobi at 2026-04-03T14:23:11-04:00
```
Add regression test for #16145

Closes #16145.
```

c1fc1c44

by Simon Peyton Jones at 2026-04-03T19:56:07-04:00

Refactor eta-expansion in Prep

The Prep pass does eta-expansion but I found cases where it was
doing bad things.  So I refactored and simplified it quite a bit.

In the new design
* There is no distinction between `rhs` and `body`; in particular,
  lambdas can now appear anywhere, rather than just as the RHS of
  a let-binding.

* This change led to a significant simplification of Prep, and
  a more straightforward explanation of eta-expansion. See the new
     Note [Eta expansion]

* The consequences is that CoreToStg needs to handle naked lambdas.
  This is very easy; but it does need a unique supply, which forces
  some simple refactoring.  Having a unique supply to hand is probably
  a good thing anyway.

21beda2c

by Simon Peyton Jones at 2026-04-03T19:56:07-04:00

Clarify Note [Interesting dictionary arguments]

Ticket #26831 ended up concluding that the code for
GHC.Core.Opt.Specialise.interestingDict was good, but the
commments were a bit inadequate.

This commit improves the comments slightly.

3eaac1f2

by Simon Peyton Jones at 2026-04-03T19:56:07-04:00

Make inlining a bit more eager for overloaded functions

If we have
   f d = ... (class-op d x y) ...
we should be eager to inline `f`, because that may change the
higher order call (class-op d x y) into a call to a statically
known function.

See the discussion on #26831.

Even though this does a bit /more/ inlining, compile times
decrease by an average of 0.4%.

Compile time changes:

 DsIncompleteRecSel3(normal)     431,786,104  -2.2%
    ManyAlternatives(normal)     670,883,768  -1.6%
    ManyConstructors(normal)   3,758,493,832  -2.6% GOOD
MultilineStringsPerf(normal)      29,900,576  -2.8%
            T14052Type(ghci)   1,047,600,848  -1.2%
              T17836(normal)     392,852,328  -5.2%
              T18478(normal)     442,785,768  -1.4%
             T21839c(normal)     341,536,992 -14.1% GOOD
               T3064(normal)     174,086,152  +5.3%  BAD
               T5631(normal)     506,867,800  +1.0%
      hard_hole_fits(normal)     209,530,736  -1.3%
 info_table_map_perf(normal)  19,523,093,184  -1.2%
          parsing001(normal)     377,810,528  -1.1%
          pmcOrPats(normal)       60,075,264  -0.5%

                                 geo. mean    -0.4%
                                 minimum     -14.1%
                                 maximum      +5.3%

Runtime changes
    haddock.Cabal(normal)   27,351,988,792  -0.7%
     haddock.base(normal)   26,997,212,560  -0.6%
 haddock.compiler(normal)  219,531,332,960  -1.0%

Metric Decrease:
    LinkableUsage01
    ManyConstructors
    T17949
    T21839c
    T13035
    TcPlugin_RewritePerf
    hard_hole_fits

Metric Increase:
    T3064

5cbc2c82

by Matthew Pickering at 2026-04-03T19:57:02-04:00

bytecode: Add magic header/version to bytecode files

In order to avoid confusing errors when using stale interface files (ie
from an older compiler version), we add a simple header/version check
like the one for interface files.

Fixes #27068

d95a1936

by fendor at 2026-04-03T19:57:02-04:00

Add constants for bytecode in-memory buffer size

Introduce a common constant for the default size of the .gbc and
.bytecodelib binary buffer.

The buffer is by default set to 1 MB.

b822c30a

by mangoiv at 2026-04-03T19:57:49-04:00

testsuite: filter stderr for static001 on darwin

This reactivates the test on x86_64 darwin as this should have been done
long ago and ignores warnings emitted by ranlib on newer version of the
darwin toolchain since they are benign. (no symbols for stub libraries)

Fixes #27116

28ce1f8a

by Andreas Klebinger at 2026-04-03T19:58:44-04:00

Give the Data instance for ModuleName a non-bottom toConstr implementation.

I've also taken the liberty to add Note [Data.Data instances for GHC AST Types]
describing some of the uses of Data.Data I could find.

Fixes #27129

8ca41ffe
by mangoiv at 2026-04-03T19:59:30-04:00
```
issue template: fix add bug label
```

3981db0c

by Sylvain Henry at 2026-04-03T20:00:33-04:00

Add more canned GC functions for common register patterns (#27142)

Based on analysis of heap-check sites across the GHC compiler and Cabal,
the following patterns were not covered by existing canned GC functions
but occurred frequently enough to warrant specialisation:

  stg_gc_ppppp  -- 5 GC pointers
  stg_gc_ip     -- unboxed word + GC pointer
  stg_gc_pi     -- GC pointer + unboxed word
  stg_gc_ii     -- two unboxed words
  stg_gc_bpp    -- byte (I8) + two GC pointers

Adding these reduces the fraction of heap-check sites falling back to
the generic GC path from ~1.4% to ~0.4% when compiling GHC itself.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

d17d1435

by Matthew Pickering at 2026-04-03T20:01:19-04:00

Make home unit dependencies stored as sets

Co-authored-by: Wolfgang Jeltsch <wolfgang@well-typed.com>

92a97015

by Simon Peyton Jones at 2026-04-05T00:58:57+01:00

Add Invariant (NoTypeShadowing) to Core

This commit addresses #26868, by adding
a new invariant (NoTypeShadowing) to Core.

See Note [No type-shadowing in Core] in GHC.Core

8b5a5020

by Simon Peyton Jones at 2026-04-05T00:58:57+01:00

Major refactor of free-variable functions

For some time we have had two free-variable mechanims for types:

* The "FV" mechanism, embodied in GHC.Utils.FV, which worked OK, but
  was fragile where eta-expansion was concerned.

* The TyCoFolder mechanism, using a one-shot EndoOS accumulator

I finally got tired of this and refactored the whole thing, thereby
addressing #27080.   Now we have

* `GHC.Types.Var.FV`, which has a composable free-variable result type,
  very much in the spirit of the old `FV`, but much more robust.
  (It uses the "one shot trick".)

* GHC.Core.TyCo.FVs now has just one technology for free variables.

All this led to a lot of renaming.

There are couple of error-message changes.  The change in T18451
makes an already-poor error message even more mysterious.  But
it really needs a separate look.

We also now traverse the AST in a different order leading to a different
but still deterministic order for FVs and test output has been adjusted
accordingly.

4bf040c6

by sheaf at 2026-04-05T14:56:29-04:00

Add utility pprTrace_ function

This function is useful for quick debugging, as it can be added to a
where clause to pretty-print debugging information:

  fooBar x y
    | cond      = body1
    | otherwise = body2
    where
      !_ = pprTrace_ "fooBar" $
           vcat [ text "x:" <+> ppr x
                , text "y:" <+> ppr y
                , text "cond:" <+> ppr cond
                ]

502e6ffe

by Andrew Lelechenko at 2026-04-07T04:47:21-04:00

base: improve error message for Data.Char.chr

As per https://github.com/haskell/core-libraries-committee/issues/384

b21bd52e
by Simon Peyton Jones at 2026-04-07T04:48:07-04:00
```
Refactor FunResCtxt a bit

Fixes #27154
```

7fe84ea5

by Zubin Duggal at 2026-04-07T19:11:52+05:30

compiler: Warn when -finfo-table-map is used with -fllvm

These are currently not supported together.

Fixes #26435

4a45a7da

by Matthew Pickering at 2026-04-08T04:37:29-04:00

packaging: correctly propagate build/host/target to bindist configure script

At the moment the host and target which we will produce a compiler for
is fixed at the initial configure time. Therefore we need to persist
the choice made at this time into the installation bindist as well so we
look for the right tools, with the right prefixes at install time.

In the future, we want to provide a bit more control about what kind of
bindist we produce so the logic about what the host/target will have to
be written by hadrian rather than persisted by the configure script. In
particular with cross compilers we want to either build a normal stage 2
cross bindist or a stage 3 bindist, which creates a bindist which has a
native compiler for the target platform.

Fixes #21970

Co-authored-by: Sven Tennie <sven.tennie@gmail.com>

b0950df6

by Sven Tennie at 2026-04-08T04:37:29-04:00

Cross --host and --target no longer required for cross (#21970)

We set sane defaults in the configure script. Thus, these paramenters
aren't required any longer.

fef35216

by Sven Tennie at 2026-04-08T04:37:30-04:00

ci: Define USER_CONF_CC_OPTS_STAGE2 for aarch64/mingw

ghc-toolchain doesn't see $CONF_CC_OPTS_STAGE2 when the bindist gets
configured. So, the hack to override the compiler gets lost.

8dd6f453

by Cheng Shao at 2026-04-08T04:38:11-04:00

ghci: use ShortByteString for LookupSymbol/LookupSymbolInDLL/LookupClosure messages

This patch refactors ghci to use `ShortByteString` for
`LookupSymbol`/`LookupSymbolInDLL`/`LookupClosure` messages as the
first part of #27147.

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

371ef200

by Cheng Shao at 2026-04-08T04:38:11-04:00

ghci: use ShortByteString for MkCostCentres message

This patch refactors ghci to use `ShortByteString` for `MkCostCentres`
messages as a first part of #27147. This also considerably lowers the
memory overhead of breakpoints when cost center profiling is enabled.

-------------------------
Metric Decrease:
    interpreter_steplocal
-------------------------

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

4a122bb6

by Phil Hazelden at 2026-04-08T20:49:42-04:00

Implement modifiers syntax.

The `%m` syntax of linear types is now accepted in more places, to allow
use by future extensions, though so far linear types is still the only
consumer.

This may break existing code where it

* Uses -XLinearTypes.
* Has code of the form `a %m -> b`, where `m` can't be inferred to be
  kind Multiplicity.

The code can be fixed either by adding a kind annotation, or by setting
`-XLinearTypes -XNoModifiers`.

Proposal:
https://github.com/ghc-proposals/ghc-proposals/blob/master/proposals/0370-modifiers.rst

07267f79

by Zubin Duggal at 2026-04-08T20:50:25-04:00

hadrian: Don't include the package hash in the haddock directory

Since GHC 9.8 and hash_unit_ids, haddock urls have looked like`ghc-9.10.3/doc/html/libraries/base-4.20.2.0-39f9/**/*.html`

The inclusion of the hash makes it hard for downstream non-boot packages to properly link to these files, as the hash is not
part of a standard cabal substitution.

Since we only build one version of each package, we don't need the hash to disambiguate anything, we can just remove it.

Fixes #26635

0a83b95b

by ARATA Mizuki at 2026-04-08T20:51:18-04:00

testsuite: Allow multiple ways to be run by setting multiple command-line options

This patch allows multiple `--test-way`s to take effect, like:

$ hadrian/build test --test-way=normal --test-way=llvm

Previously, only one way was run if the test speed was 'normal' or 'fast'.

Closes #26926

Co-authored-by: sheaf <sam.derbyshire@gmail.com>

e841931c

by Teo Camarasu at 2026-04-08T20:52:00-04:00

doc: improve eventlog-flush-interval flag documentation

We mention the performance cost and how this flag can be turned off.

Resolves #27056

e332db25
by Teo Camarasu at 2026-04-08T20:52:01-04:00
```
docs/user_guide: fix typo
```

5b82080a

by Simon Jakobi at 2026-04-08T20:52:44-04:00

Fix -dsuppress-uniques for free variables in demand signatures

Before:          Str=b{sXyZ->S}
With this patch: Str=b{S}

T13143.stderr is updated accordingly.

Fixes #27106.

b7a084cc

by Simon Jakobi at 2026-04-08T20:53:27-04:00

Documentation fixes for demand signature notation

Fixes #27115.

59391132

by Simon Jakobi at 2026-04-08T20:54:08-04:00

Use upsert for non-deleting map updates

Some compiler functions were using `alter`, despite never removing
any entries: they only update an existing entry or insert a new one.

These functions are converted to using `upsert`:

    alter  :: (Maybe a -> Maybe a) -> Key -> Map a -> Map a
    upsert :: (Maybe a ->       a) -> Key -> Map a -> Map a

`upsert` variants are also added to APIs of the various Word64Map
wrapper types.

The precedent for this `upsert` operation is in the containers library:
see https://github.com/haskell/containers/pull/1145

    Metrics: compile_time/bytes allocated
    -------------------------------------

        geo. mean:    -0.1%
        minimum:      -0.5%
        maximum:      +0.0%

Resolves #27140.

da7e82f4

by Cheng Shao at 2026-04-08T20:54:49-04:00

testsuite: fix testsuite run for +ipe again

This patch makes the +ipe flavour transformer pass the entire
testsuite again by dropping stdout/stderr checks of certain tests that
are sensitive to stack layout changes with `+ipe`. Related: #26799.

b135a87d

by Zubin Duggal at 2026-04-09T19:36:50+05:30

Bump directory submodule to 1.3.11.0 (unreleased)

3a291d07
by Zubin Duggal at 2026-04-09T19:36:50+05:30
```
Bump file-io submodule to 0.2.0
```
e0ab606d
by Zubin Duggal at 2026-04-10T18:40:20+05:30
```
Release notes for GHC 10.0
```
e08b9b34
by Zubin Duggal at 2026-04-10T18:40:20+05:30
```
Bump ghc-prim version to 0.14.0
```

a92aac6e

by Zubin Duggal at 2026-04-10T18:40:20+05:30

Bump template-haskell to 2.25.0.0; update submodule exceptions for TH 2.25

f254d9e8
by Zubin Duggal at 2026-04-10T18:40:20+05:30
```
Bump GHC version to 10.0
```

6ce0368a

by Zubin Duggal at 2026-04-10T18:40:28+05:30

Bump base to 4.23.0.0; update submodules for base 4.24 upper bound

702fb8a5

by Zubin Duggal at 2026-04-10T18:40:28+05:30

Bump GHC version to 10.1; update submodules template-haskell-lift and template-haskell-quasiquoter for ghc-internal 10.200

75df1ca4

by Zubin Duggal at 2026-04-10T18:40:28+05:30

Use changelog.d for release notes (#26002)

GHC now uses a fragment-based changelog workflow using a custom script adapted from https://codeberg.org/fgaz/changelog-d.

Contributors add a file in changelog.d/ for each user-facing change.
At release time, these are assembled into release notes for sphinx (in RST) format, using
the tool.

New hadrian `changelog` target to generate changelogs

CI job to validate changelog entries for MRs unless skipped with ~"no-changelog" label

Teach sphinx about ghc-mr: extlink to link to MRs

Remove `ghc-package-list` from sphinx, and implement it in changelog-d instead (Fixes #26476).

(cherry picked from commit 989c07249978f418dfde1353abfad453f024d61a)

585d7450

by Luite Stegeman at 2026-04-11T02:17:13-04:00

tc: discard warnings in tcUserStmt Plan C

We typecheck let_stmt twice, but we don't want the warnings twice!

see #26233

2df604e9

by Sylvain Henry at 2026-04-11T02:19:30-04:00

Introduce TargetInt to represent target's Int (#15973)

GHC was using host 'Int' in several places to represent values that
live in the target machine's 'Int' type.  This is silently wrong when
cross-compiling from a 32-bit host to a 64-bit target: the host Int
is 32 bits while the target Int is 64 bits.

See Note [TargetInt] in GHC.Platform.

Also used the opportunity to make DynTag = Word8.

Fixes #15973

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

d419e972

by Luite Stegeman at 2026-04-13T15:16:04-04:00

Suppress desugaring warnings in the pattern match checker

Avoid duplicating warnings from the actual desugaring pass.

fixes #25996

c5b80dd0
by Phil de Joux at 2026-04-13T15:16:51-04:00
```
Typo ~/ghc/arch-os-version/environments
```
71462fff
by Luite Stegeman at 2026-04-13T15:17:38-04:00
```
add changelog entry for #26233
```

d1ddfd4b