-
1abef1ef
by Wolfgang Jeltsch at 2026-09-25T17:02:07-04:00
Improve the `mhu-closure` makefile
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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
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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.
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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.
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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.
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234bab08
by Vladislav Zavialov at 2026-09-29T17:22:54-04:00
Add regression test for #7803
Commit 2effe18ab5, first shipped with GHC 8.2.1, fixed #7803 "Superclass
methods are left unspecialized".
This change turns the example from the ticket description into a regression
test, checking that foo1 is fully specialised at Double, with no calls to the
overloaded exp5Tail.
Closes #7803
Assisted-by: Claude Opus 5
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c406135c
by Andreas Klebinger at 2026-10-01T06:57:28-04:00
RTS: Update flag parsing/handling:
Using 0 as argument to any of these flags now resets the flags setting to default:
- ``-n0`` disables nursery chunking.
- ``-K0`` (or a bare ``-K``) removes the stack size limit.
- ``-M0`` removes the heap size limit.
- ``-H0`` resets the suggested heap size, including the nursery scaling set by ``-H``.
- ``-AL0`` makes the large object allocation limit follow ``-A`` again.
GC Generations are now limited to 64.
-n larger than -A now emits a warning and disables chunking.
Fixes #27830 #27829
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984ee82b
by Andreas Klebinger at 2026-10-01T06:58:10-04:00
Fix MultiLayerModules timeout multiplier.
We accidentally used the compile multiplier for ghci commands which
use the run timeout setting to set the timeout.
Fixes #26263 and #27796.
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50a9cf26
by Andreas Klebinger at 2026-10-01T06:58:10-04:00
testsuite: Include runtime in JUnit report.
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e358619f
by Alan Zimmerman at 2026-10-01T06:59:01-04:00
EPA: Use EpaLocation in EpVirtualBraces
Haddock processing uses EpLayout.EpVirtualBraces to record the current
layout column, for allocating haddock comments correctly.
For exact printing, we need the line as well as the col, so we know
how many lines to skip when the indented code block starts.
This commit updates EpLayout.EpVirtualBraces so that it carries an
EpaLocation instead of just the Int column, to allow it to be used for
both purposes.
It is a simple mechanical change, with no other impact, but it allows
us to use EpLayout instead of AnnListLayout in AnnList, in the next
commit in this series.
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1d2a26ee
by Andrew Lelechenko at 2026-10-01T20:22:04-04:00
Remove bitSize from MINIMAL pragma of class Bits
Cf. https://github.com/haskell/core-libraries-committee/issues/441
The function is deprecated for 12 years and has a default implementation,
yet it was never removed from the MINIMAL pragma, putting library authors
in a very awkward position. Let's finally remove bitSize from MINIMAL.
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3cc21e4c
by Hannes Siebenhandl at 2026-10-01T20:22:59-04:00
Add regression test for #27641
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c35096f5
by Hannes Siebenhandl at 2026-10-01T20:23:00-04:00
Don't `:add` modules the loader will reject
Only home modules can be actually added to the loader context, thus we
only accept the module if it belongs to a home unit.
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a563cb27
by Simon Jakobi at 2026-10-02T17:37:36-04:00
ci: accept modified changelog.d entries in lint-changelog
The changelog guide says to extend an existing entry rather than add a
new one when the feature is already documented. lint_changelog only
counted added files, so such MRs failed before the validator ran.
Fixes #27779.
Assisted-by: Claude Fable 5.1
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03082cd4
by Simon Jakobi at 2026-10-02T17:38:17-04:00
changelog.d: Fix warning flag name in the semaphore-v2 entry
The entry refers to -Wsemaphore-version-mismatch, which does not exist.
The warning GHC emits when it cannot use a -jsem semaphore, including
on a protocol version mismatch, is -Wsemaphore-open-failure.
Context: !15729, #25087
Assisted-by: Claude Fable 5.1
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a93705ee
by Simon Jakobi at 2026-10-02T17:38:17-04:00
changelog.d: Fix the CLC proposal link in the T27455 entry
The entry used the Sphinx :ref: role with a URL as its target. :ref:
resolves only internal labels, so the generated release notes would
show the proposal name without a link. Use the plain hyperlink form
like the other entries.
Context: !16274, #27455
Assisted-by: Claude Fable 5.1
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54381079
by Hannes Siebenhandl at 2026-10-02T17:39:01-04:00
Extend the `TrustOverlay` for wired-in units
The TrustOverlay only contained the `UnitId` of all on-disk units.
However, wired-in units are referred to by their wired-in unit id, which
is not the same as the on-disk unit id.
Thus, trust checks for wired-in units failed because the lookup was
using the wired-in unit, which wasn't present in the `TrustOverlay`.
We fix #27834, by copying the trust info for wired-in unit ids.
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f8cfb1a5
by Hécate Kleidukos at 2026-10-04T19:36:39+02:00
[CLC 341] Strict variants of mutable types
This commit is the implementation of CLC Proposal 341
https://github.com/haskell/core-libraries-committee/issues/341
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575c4bc6
by Rodrigo Mesquita at 2026-10-05T12:32:02-04:00
ttg: HsModuleName in the AST, ModuleName in GHC
This commit makes the AST fully independent from GHC by parsing a
"module name" as an `HsModuleName (= HText)` rather than constructing an
`ModuleName (= FastString)` straight away.
In the GHC side, everything remains as a `ModuleName`. We turn AST
`HsModuleName`s into fast strings with the cheap `mkFastStringShortText`
when we process the AST for manipulation within the compiler.
There are no performance regressions introduced by this approach.
This is the final piece of #21592
Alternative plans were discussed in
gitlab.haskell.org/ghc/ghc/-/merge_requests/16546#note_694647,
but the Simon suggested one won in simplicity and performance when
compared against my attempt at implementing my original plan of having
a family `ModuleNameP`.
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b3b89d32
by mangoiv at 2026-10-05T22:03:32-04:00
hadrian: Persist the used flavour name in the build root (#20650)
This executes the idea proposed in #20650, teaching Hadrian to persist
the flavour used to build a build root. This both makes use of multiple
build roots more ergonomic (as the user no longer needs to repeat
themselves) and avoids a tiresome foot-gun (forgetting to specify a
flavour, often wholly invalidating a build root).
Closes #20650.
Co-authored-by: Sylvain Henry <sylvain@haskus.fr>
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f977837b
by mangoiv at 2026-10-05T22:04:21-04:00
configure: fix sed script and subst tooldir script
Fixes #27672
Adds sanity checking for SUBST_TOOLDIR
Metric Decrease:
LinkableUsage01
MultiLayerModulesTH_OneShot
T10547
T12234
T12425
T13035
T13820
T18140
T18730
T18923
T9198
TcPlugin_RewritePerf
mhu-perf
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f1cb08be
by Hannes Siebenhandl at 2026-10-05T22:05:03-04:00
Prepend in-memory unit database for backpack
The packageDbFlags are stored in reverse order. Thus, prepending will
ensure that the in-memory unit database is the last item on the unit
database stack.
Further, the in-memory unit database needs to be able to shadow units
from earlier unit databases in the unit database stack.
Moreover, a `-clear-package-db` would remove the in-memory database if
it weren't the last item on the stack.
Closes #27835
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8d49ed42
by Kazu Yamamoto at 2026-10-06T19:37:25-04:00
Do not leave standard file descriptors free at startup (#24450)
A process may be started with stdout closed -- `prog >&-` from a shell does
exactly that. Nothing then reserves descriptor 1, and open(), pipe() and
socket() hand out the lowest free descriptor, so the next descriptor the
runtime creates for itself takes it: the ticker's pipe, or a capability's IO
manager control pipe.
'GHC.Internal.IO.StdHandles.stdout' is a CAF, built the first time the program
writes to stdout, which is long after that has happened. It builds a 'Handle'
over descriptor 1, which now belongs to the runtime, and nothing reports an
error because the descriptor is perfectly good. The program then writes its
output into the runtime's own plumbing.
What that looks like from the outside is a hang. The descriptor the Handle has
taken over is the read end of a pipe, so poll() for POLLOUT on it never says
yes and epoll_ctl() accepts a registration for it; the thread waiting to write
blocks for ever. Closing the Handle at exit closes the runtime's descriptor,
which is worse: the ticker then fails on every tick.
'hs_init_ghc' now opens /dev/null onto whichever of descriptors 0, 1 and 2 are
closed, before the runtime creates any descriptor of its own. Each is opened
for the access that descriptor would normally have, read-only for 0 and
write-only for 1 and 2, so that writing to 'stdin' or reading from 'stdout'
still fails rather than quietly succeeding against /dev/null. See
Note [Standard file descriptors must be open].
Moving only the descriptors the runtime opens would not do: the first file the
program itself opened would land on the free number instead. The fix has to
leave no free number. A program run this way therefore finds stdout connected
to /dev/null rather than failing with EBADF on the first write, which is what
such a program would get from most other language runtimes.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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65bcf9e9
by Simon Jakobi at 2026-10-06T19:38:09-04:00
changelog: Repair the sentence describing #27477
The description read "programs using could crash", the object of
"using" having been lost. The synopsis already says which programs are
affected, so drop the dangling word.
Assisted-by: Claude Fable 5.1
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8fffaa01
by Simon Peyton Jones at 2026-10-07T12:07:16+01:00
Refactor fundeps again
This MR fixes #27828; there was a bad scoping error in `trim_qtvs`.
The main changes are
* Refactor `trim_qtvs` completely to eliminate the bug.
* Remove a redundant `apartnessCheck` from `mkTopOpenFamEqFDs`.
* Lots of improvements to the Notes in FunDeps.hs
I also did a couple of pure refactors:
* I realised that we were carefully caching `cab_incomps` in each
`CoAxBranch`, to make it more efficient to reduce a type family application,
but we were not doing the same thing when computing relevance for functional
dependencies; see Note [Relevance] in GHC.Tc.Solver.FunDeps. So I added
`cab_overlaps`, which is now used in `noEarlierMatch`.
* Use a proper data types, `AmIUnifying` and `OuterKindsFlag`, for two
previously-Boolean arguments to `tc_unify_tys`. This is a pure refactor.