-
8fc6f882
by Simon Jakobi at 2026-08-05T14:53:41-04:00
testsuite: Don't crash on non-UTF-8 test output
read_stdout, read_stderr_for, read_comp_stderr and read_diff decoded
strictly (the first three with UTF-8, read_diff with the locale
encoding), so a test emitting invalid UTF-8 (binary output, or a crash
truncating a multi-byte character) raised UnicodeDecodeError and was
reported as a framework failure instead of its actual result.
Decode with errors='replace', like read_no_crs and safe_print.
Assisted-by: Claude Fable 5
-
56534866
by Simon Jakobi at 2026-08-05T14:53:41-04:00
testsuite: Colorize the test summary, also in CI
The summary headings were plain, and SUMMARY was colored unconditionally,
so the escapes also ended up in the file written by --summary-file.
Color is now decided per output sink via term_color.colored_if; see the
comments in term_color.
CI logs are not a tty, but GitLab's log viewer renders ANSI colors, so
add --force-colors and pass it in .gitlab/ci.sh.
Assisted-by: Claude Opus 5
-
bceb541a
by Simon Jakobi at 2026-08-05T14:53:42-04:00
testsuite: Repeat unexpected failure output in the summary
Finding out why a test failed meant scrolling back through a possibly
very long log to the point where the test ran. The summary now repeats
the captured output of unexpected failures, before the statistics, so
the most interesting part is at the end of the log (#16720).
Output mismatches report their diff instead of the mismatching stream
(see Note [Redundant output in test results]). The repeated output is
bounded per stream, and skipped altogether beyond
MAX_SUMMARY_OUTPUT_TESTS failure blocks. Tests failing identically in
several ways share one block.
Test results now report a source-relative directory, stable regardless
of where the run was started from.
Assisted-by: Claude Fable 5
-
2ab02c57
by Ben Gamari at 2026-08-05T14:54:24-04:00
base: Don't drop exception context in SomeException(toException)
For reasons that are lost to time, the implementation of [CLC #200]
that was merged inappropriately dropped `ExceptionContext` in the
`toException` implementation given to `SomeException`.
Fix this infelicity.
[CLC #200]: https://github.com/haskell/core-libraries-committee/issues/200
-
126ce574
by Vladislav Zavialov at 2026-08-05T14:55:05-04:00
Test case for #20902
Starting with GHC 9.14.1 (the first major release to include 51e3ec83),
and from point releases GHC 9.10.2 and GHC 9.12.3 (backports cc4470be68
and b30f25591e), all examples in this ticket are handled as expected.
-
b14d8d59
by Alan Zimmerman at 2026-08-05T14:55:46-04:00
EPA: Remove LocatedP, last use in WarningTxt
The last step of removing LocatedP, by moving the AnnPragma for
WarningTxt into its TTG extension point instead.
This also allows us to remove LocatedP and SrcSpanAnnP
-
70b58c8f
by Vladislav Zavialov at 2026-08-05T14:56:27-04:00
Test cases for #18725
Starting with GHC 9.4 (the first release to include 268efcc9a4), the program in
this ticket no longer panics. A standalone kind signature breaks the recursive
loop, so the type constructor can be used in a kind within its own group.
T18725a checks that this is accepted with the signature present, while T18725b
confirms it is still rejected without it.
-
b18c8dd5
by Zubin Duggal at 2026-08-06T15:51:01-04:00
hie files: Dump the type table when dumping with -ddump-hie
-
f839d0fb
by Zubin Duggal at 2026-08-06T15:51:01-04:00
hie files: Take evidence for quantified constraints into account when saving evidence terms to the hie ast
Fixes #25709
-
5753ebaa
by Simon Jakobi at 2026-08-06T15:51:43-04:00
testsuite: fix stale paths for the ghc-config build artifacts
ghc-config.hs moved from testsuite/mk/ to testsuite/ghc-config/ in
6c7a49139c, but the .gitignore entry and the clean rule still referred to
the old location. As a result the compiled ghc-config binary, which
boilerplate.mk rebuilds on every make-driven test run, showed up as an
untracked file and was never cleaned.
Assisted-by: Claude Opus 5
-
246d4d72
by Simon Peyton Jones at 2026-08-06T15:52:25-04:00
Documentation only
...driven by my investigation of #27591
-
be69e9df
by Alan Zimmerman at 2026-08-06T15:53:05-04:00
EPA: Replace AnnPragma with individual types
We introduced AnnPragma as a common type for all pragma usages wrapped
in LocatedP / SrcSpanAnnP. Now that those are gone, and the AnnPragma
moved into the TTG points for the given items, we can ensure that each
carries only the annotations it needs.
So we remove AnnPragma, and in its place bring in
AnnCType
AnnWarningTxt
AnnOverlap
AnnAnnDecl
AnnPragSCC
-
0779e12c
by Simon Jakobi at 2026-08-07T12:36:11-04:00
Cmm: print unreachable blocks under -dppr-debug (#27368)
Unreachable blocks linger in a CmmGraph's block map for most of the Cmm
pipeline, but pprCmmGraph only ever printed the blocks reachable from the
entry, so dumps looked consistent while the graph was not. Issues like
#27368 were hard to debug due to this.
pprCmmGraph now appends the stored-but-unreachable blocks under a
"// unreachable blocks:" heading when -dppr-debug is on.
See Note [unreachable blocks] in GHC.Cmm.Pipeline.
Assisted-by: Claude Opus 5
-
3a0f9a51
by Simon Peyton Jones at 2026-08-07T12:36:54-04:00
Fix three bugs related to required type args and INLINE pragmas
* `GHC.Core.Opt.Arity.mkEtaForAllMCo` got the visibility flags back to front,
leading to a Lint error (#27557)
* The arity in an InlineSaturation is the VisArity not the Arity; the
two can differ when we have "required" type arguments. This made the
INLINE pragma argument counting go wrong in `makeCorePair` (#27590).
* When a simple binding has a type signature, we take special path in `tcPolyCheck`,
leading to an outer `AbsBinds` that has no dictionaries, even when the binding
is in fact overloaded. That confused the inline-arity computation in
`makeCorePair` (#27589).
The latter two are fixed using the new function `GHC.HsToCore.Binds.findSatArity`.
That actually simplifies the API of `makeCorePair`, which is nice.
The first bug is fixed by swapping the visiblity flags in
`GHC.Core.Opt.Arity.mkEtaForAllMCo`
Getting the INLINE behaviour right led to some perf changes:
* Runtime /halved/ on T7954 due to better specialisation
* Compile time increased by 6% in T21839c because a bit more inlining
happened, as it always should have done.
* For some reason compile-time max-bytes-used dropped by 30% on
T27336, but only on one build configuration; and it increased
on LinkableUsage02 by 6% on another configuration
Geometric mean effect on our compile time benchmarks is +0.1%.
Metric Decrease:
T27336
T7954
Metric Increase:
LinkableUsage02
T21839c
-
4f985108
by Vladislav Zavialov at 2026-08-07T17:49:50-04:00
Discard type arguments in tcPatToExpr (#27440, #27583)
The builder expression of an implicitly bidirectional pattern synonym must not
mention types written in the RHS:
* Invisible type arguments led to a panic (#27440)
* Required type arguments failed with out-of-scope variables (#27583)
Both are now discarded, following the precedent established by pattern
signatures (#9867).
Discarding type arguments takes some care: a type pattern cannot be told from a
value pattern by syntax alone, as the `type` keyword may be omitted. Consider:
data T a b c where
MkT :: forall a. forall b c -> a -> T a b c
pattern P :: x -> T x y z
pattern P x = MkT @a (type b) c x
In P's right-hand side, `@a` and `type b` are clearly type arguments, but what
about `c` and `x`? We can only tell by matching the patterns against MkT's
type. So tcPatToExpr now runs in TcM and matches the arguments against the
constructor's TyVarBinders using zipPatsBndrs, which is made public for this
purpose. The resulting builder is $bP x = MkT _ _ x.
See Note [Discarding types in the builder expression].
Test cases: T27440a T27440b T27440c T27440d T27440e
T27583a T27583b T27583c T27583d T27583e T27583f T27583g
Metric Increase: LinkableUsage02
Metric Decrease: T27336
Assisted-by: Claude Opus 5
-
eb1dcd4d
by sheaf at 2026-08-07T17:50:40-04:00
mkWpFun_FRR: fix ordering of coercion composition
When the subsumption machinery generates an eta-expansion, we must
perform a representation polymorphism check to ensure the lambda binder
it introduces has a fixed runtime representation.
This is done in GHC.Tc.Utils.mkWpFun_FRR.
This check involves composing quite a few coercions, arising from
representation-polymorphism checks on both the actual and expected
argument types. These coercions are then chained using HsWrapper
composition, <.>. The ordering of composition was incorrect, leading to
the Core Lint failure reported in #27639. This commit fixes that.
Fixes #27639
-
3a552476
by Simon Jakobi at 2026-08-09T15:20:06-04:00
Word64Map: add compareSize
compareSize m c compares the size of a map to an Int, but unlike
compare (size m) c it stops traversing the map once the outcome is
determined.
Based on https://github.com/haskell/containers/pull/1139
Assisted-by: Claude Opus 5
-
6e2c99d8
by Simon Jakobi at 2026-08-09T15:20:06-04:00
Use a pigeonhole sort for deterministic UniqDFM iteration
Deterministic UniqDFM iteration used a list mergesort, allocating O(n
log n) cons cells and contributing significantly to compiler allocations
(#27459).
Use a pigeonhole sort where appropriate, while retaining the mergesort
fallback. See Note [Sorting a UDFM] and Note [Cost of deterministic
iteration].
The peak_megabytes_allocated increase for LinkableUsage02 is probably
due to GC timing noise. See #27613.
-------------------------
Metric Decrease:
InstanceMatching
InstanceMatching1
ManyAlternatives
T12707
T13379
T13719
T24471
T27336
T5321FD
T5321Fun
T783
Metric Increase 'peak_megabytes_allocated':
LinkableUsage02
-------------------------
Assisted-by: gpt-5.6-sol via Codex CLI
-
a938ab12
by sheaf at 2026-08-09T15:20:48-04:00
Testsuite: don't measure max residency for T27336
We really care more about total allocations for this test, so this commit
removes the maximum residency measurement.
-
7d94bb78
by Alan Zimmerman at 2026-08-09T15:21:29-04:00
EPA: Remove LocatedE, replace with LocatedA
This gets rid of one more LocatedXXX occurrence
-
9df24b7e
by sheaf at 2026-08-10T14:28:30-04:00
hie.yaml: use a polyglot shell/batch script
This commit merges hie-bios and hie-bios.bat into a single polyglot
script. This avoids Windows users having to manually update hie.yaml
in order to be able to use HLS.
-
7f75c588
by Alan Zimmerman at 2026-08-10T14:29:11-04:00
EPA: Remove type parameter from AnnList
This is a step towards cutting AnnList down to its core for formatting
lists only
-
e8d1a0d6
by Bernhard M. Wiedemann at 2026-08-10T21:31:23-04:00
driver: Link object files in a deterministic order
The object files handed to the linker come from the HomePackageTable,
which is ordered by the order in which modules finished compiling. With
-j1 that is the build plan order, with -jN it is whatever the scheduler
produced, so the same sources can link to different (but equivalent)
binaries.
The order reaches the output: .text and .rodata contributions are
concatenated in link order, so e.g. building the hdav executable of the
DAV package twice, once with -j1 and once with -j4, yields two binaries
that differ in ~100kB of section contents.
Sort the home modules by module before collecting their linkables,
guarded under `Opt_ObjectDeterminism` .
Fixes #27612
Signed-off-by: Bernhard M. Wiedemann <bwiedemann@suse.de>
-
556db2f3
by sheaf at 2026-08-10T21:32:06-04:00
Reduce SpecConstr threshold in GHC.Tc.Solver.Rewrite
As remarked in #27628, this module currently sits on a knife's edge: if
the body of 'simplifyArgsWorker' is made even a tiny bit smaller, then
SpecConstr suddenly kicks in and causes disastrous reboxing of the
LiftingContext argument.
To make this less likely to happen, this commit lowers the SpecConstr
threshold.
-
c77d88fc
by sheaf at 2026-08-13T10:15:22-04:00
Allow rewriting in RuntimeReps for newtype ConPats
This commit implements PHASE 2 of the FixedRuntimeRep plan described in
Note [The Concrete mechanism] in GHC.Tc.Utils.Concrete for newtype
constructor patterns.
In short, GHC now accepts programs of the form
f (MkN x) = ...
in which the argument 'x' of the newtype constructor pattern 'MkN x'
has a representation that is not syntactically concrete, e.g. it can be
'Id IntRep' reducing to 'IntRep'. See T20363{,b,c} for examples.
There are two main parts to the implementation:
1. Typechecking, in GHC.Tc.Gen.Pat.tcDataConPat.
See Note [Typechecking newtype constructor patterns] in GHC.Tc.Gen.Pat.
2. Desugaring. We restructure the code for desugaring pattern matches
by allowing the scrutinised match variable to be casted. This allows
us to accumulate coercions and avoids creating binders at intermediate
types tha don't have a fixed RuntimeRep.
See the revamped Note [Match Ids] in GHC.HsToCore.Monad.
Fixes #20363
-------------------------
Metric Increase:
InstanceMatching
-------------------------
-
6ba9dd41
by Wolfgang Jeltsch at 2026-08-13T10:16:07-04:00
Improve the documentation of `--show-iface`
This change in particular gets rid of the claim that `--show-iface`
writes *the* contents of the interface file in question. It doesn’t do
that; it only writes those parts that are likely of interest to a human
reader.
-
4bd193fa
by Sylvain Henry at 2026-08-13T10:17:00-04:00
RTS: fix LDV profiler's slop skipping (#27585)
processHeapForDead was the one heap scanner not updated for the slop
marker encoding introduced in #19048. It still assumed slop is zeroed:
while (p < bd->free && !*p) p++; // skip slop
so it stopped at the (StgWord)(-1) sentinel and passed it to
processHeapClosureForDead. IS_FORWARDING_PTR(-1) holds, hence a garbage
size was read out of LDVW and the scan ran off the block, tripping
ASSERT(p == bd->free) on a debug RTS and silently corrupting the census
otherwise.
The loop was hand-copied in four places, so factor it out into skipSlop
in ClosureMacros.h and use it in ProfHeap.c, Sanity.c, Printer.c and
LdvProfile.c.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
-
1446bb03
by Zubin Duggal at 2026-08-13T10:17:48-04:00
hadrian: Fix links to remaining doc sites to not use the package hash for haddock links
In 07267f79d91169f474cacc8bcd38d76a6e97887d we changed hadrian to not include the package hash in the haddock
directory. This patch takes care of a few remaining links that were missed in that patch
Fixes #27671
-
257c3ed7
by Simon Jakobi at 2026-08-13T10:18:29-04:00
Testsuite: widen InstanceMatching acceptance window to 5% (#27673)
...in order to unblock CI.
Assisted-by: Claude Fable 5
-
e4cfaaa0
by Simon Peyton Jones at 2026-08-14T01:09:32+02:00
Major patch to re-engineer known-key names
This big patch implements the New Plan for known-key names,
described in #27013.
Read the big Note [Overview of known-key names] in GHC.Types.Name
Some things had to be reworked slightly to accomodate the new known-keys
design. A significant one was the generation of auxiliary KindRep
bindings, which was greatly simplified. Note [Grand plan for Typeable]
was updated accordingly. Another example: GHC.Internal.CString was
merged into GHC.Internal.Types.
Co-authored-by: Rodrigo Mesquita <rodrigo.m.mesquita@gmail.com>
The couple hundreds of hours spent here by Rodrigo were sponsored by Well-Typed
Metrics: compile_time/bytes allocated
-------------------------------------
Baseline
Test Metric value New value Change
------------------------------------------------------------------------------------------
MultiComponentModules100(normal) ghc/alloc 24,312,779,672 24,990,470,432 +2.8% BAD
MultiComponentModulesRecomp(normal) ghc/alloc 601,924,960 621,884,888 +3.3% BAD
MultiComponentModulesRecomp100(normal) ghc/alloc 11,884,065,432 12,531,373,704 +5.4% BAD
MultiLayerModules(normal) ghc/alloc 3,861,537,072 3,706,919,512 -4.0% GOOD
T13701(normal) ghc/alloc 3,517,246,392 3,237,179,616 -8.0% GOOD
T13820(normal) ghc/alloc 28,961,056 29,663,208 +2.4% BAD
T14697(normal) ghc/alloc 472,044,184 443,550,048 -6.0% GOOD
T18140(normal) ghc/alloc 47,905,664 49,115,808 +2.5% BAD
T4801(normal) ghc/alloc 269,339,096 263,432,040 -2.2% GOOD
T783(normal) ghc/alloc 341,112,672 333,339,952 -2.3% GOOD
hard_hole_fits(normal) ghc/alloc 222,164,728 213,433,808 -3.9% GOOD
mhu-perf(normal) ghc/alloc 49,011,440 46,706,280 -4.7% GOOD
geo. mean +0.1%
minimum -8.0%
maximum +5.4%
All performance regressions were investigated in depth. The surviving
ones:
- MultiComponentModules100, MultiComponentModulesRecomp100,
MultiComponentModulesRecomp regresses because existing bugs that make
an additional implicit edge do too much redundant work: #27053 and #27461
- T13820, T18140, T10547, T13035 regress because we load an additional
interface and associated Names for GHC.Essentials.
-------------------------
Metric Decrease:
MultiLayerModules
T13379
T13701
T14697
T26989
T4801
T783
T9961
hard_hole_fits
mhu-perf
size_hello_artifact
size_hello_obj
size_hello_unicode
Metric Increase:
LinkableUsage01
LinkableUsage02
MultiComponentModules100
MultiComponentModulesRecomp
MultiComponentModulesRecomp100
T10547
T13035
T13820
T18140
T18698a
T18698b
T20049
-------------------------
Bumps submodule binary
Closes #27013
-
61665e79
by sheaf at 2026-08-14T01:09:33+02:00
Allow GHC.Essentials to be hidden
This commit overhauls several aspects of the known entity handling,
in order to allow GHC.Essentials to be hidden without a proliferation
of special cases in the compiler.
The main contribution is to introduce the 'UnresolvedImport' datatype
which cleans up a lot of ad-hoc handling relating to 'ModSummary',
fixing #27603. This allows us to reduce duplication, e.g. by having
Backpack reuse 'mkUnresolvedImports' instead of replicating the
"add implicit imports" logic. It also makes it easier to avoid
undesirable edge cases (such as making sure that the Template Haskell
'reifyModule' function does not leak the implicit GHC.Essentials import).
In particular, the infamous 'findImportedModuleWithIsBoot' is now simply
'resolveImport', taking a single 'UnresolvedImport' and resolving it
to a 'FindResult' (usually a 'Module').
Other changes:
- Cache the result of looking up GHC.Essentials (in TcM and DsM
environments) to avoid redundant work.
This reduces allocations on LinkableUsage01 and hard_hole_fits.
- Properly look up known entities for StaticPointers like we do for
other known entities everywhere else. This allows e.g. modules in
ghc-internal to use -XStaticPointers.
- When using multiple home units, we are now careful to handle the
situation in which we may have multiple GHC.Essentials modules
around. See the new tests under 'driver/multipleHomeUnits'.
-
b19fcc1c
by Vladislav Zavialov at 2026-08-14T06:26:11-04:00
Increase test coverage of diagnostics, batch 2
Add test cases for the previously untested diagnostics:
[GHC-26133] TcRnForeignImportPrimSafeAnn
[GHC-68444] SumAltArityExceeded
[GHC-63966] IllegalSumAlt
[GHC-23882] IllegalDeclaration
[GHC-60220] InvalidCCallImpent
[GHC-18816] RecGadtNoCons
[GHC-38140] GadtNoCons
[GHC-37056] InvalidTypeInstanceHeader
[GHC-78486] InvalidTyFamInstLHS
[GHC-39639] DefaultDataInstDecl
[GHC-78822] AssocDefaultNotAssoc
[GHC-43510] NotSimpleUnliftedType
[GHC-41843] IOResultExpected
[GHC-07641] AtLeastOneArgExpected
[GHC-52886] InvalidTopDecl
Remove unused error constructors:
[GHC-92057] ImportLookupAmbiguous
-
7b27f25a
by Simon Jakobi at 2026-08-14T06:26:54-04:00
testsuite: Drop peak_megabytes_allocated from LinkableUsage tests
LinkableUsage01/02 collected all metrics with a 2% tolerance. For
peak_megabytes_allocated, whose granularity is 1 MB, that window is
under 0.7 MB at this test's ~34 MB peak, so any 1 MB step failed the
test (#27613, #27489). Drop that metric: max_bytes_used guards the
Linkable-retention property with byte granularity, at a tolerance
that still comfortably exceeds the noise observed in CI.
Assisted-by: Claude Fable 5
-
e5de423b
by Simon Jakobi at 2026-08-14T06:26:54-04:00
testsuite: Don't truncate fractional baselines when computing bounds
RelativeMetricAcceptanceWindow.get_bounds truncated the baseline with
int() before applying the tolerance. Baselines can be fractional (they
are averaged over several measurements), so this skewed the acceptance
window downwards: in #27613, a baseline of 33.67 at 2% tolerance
yielded bounds (32, 34) instead of (32, 35), rejecting a measurement
that was within tolerance.
Assisted-by: Claude Fable 5
-
af8c9695
by Simon Jakobi at 2026-08-14T12:54:21+02:00
testsuite: Migrate perf tests off collect_compiler_stats('all')
The 'all' metric argument applies a single tolerance to bytes
allocated, max_bytes_used and peak_megabytes_allocated, although their
noise profiles are incompatible (#27653): allocations are nearly
deterministic, residency needs 10-20%, and peak is quantized to 1 MB.
Any single tolerance is too tight for one metric or too slack for
another. This migrates the remaining users of 'all' (and of the 'all'
default) to explicit per-metric collection, ahead of removing 'all'
from the driver.
peak_megabytes_allocated is dropped everywhere: its 1 MB granularity
makes tight relative windows meaningless (#27613), and it is sensitive
to GC timing. In #27489 it drifted by -5.3% while max_bytes_used moved
by less than 0.1%. Where a test guards a memory property,
max_bytes_used covers it at byte granularity.
Where the motivating ticket was about compile-time memory
(T11545, T15304, T26425), residency remains gated via max_bytes_used,
now with a residency-appropriate tolerance.
max_bytes_used is dropped where residency was only ever an accident of
'all':
* T15630, T15630a, T20261: the underlying tickets (#15630, #20261)
contain no memory data at all. One is a simplifier-ticks blowup and
the other is stated entirely in allocation numbers, so the 20%
window never had teeth.
* T21839c: #21839's measurements show residency essentially flat
(+0.16%) while allocations moved +7%, so allocations are the
discriminating metric. They are already gated at 1% via
collect_compiler_runtime. The ghc/max gate had previously broken CI
spuriously (9fd11585eb widened it from 1% to 10% for that reason).
Allocation tolerances are tightened to the testsuite's conventional 2%
where 'all' previously left them at 10-20%.
Assisted-by: Claude Fable 5
-
f10e513c
by Simon Jakobi at 2026-08-14T12:54:21+02:00
testsuite: Remove the 'all' metric argument of collect_stats
'all' gated bytes allocated, max_bytes_used and peak_megabytes_allocated
at a single tolerance, although their noise profiles are incompatible,
making such tests either flaky or toothless (#27653).
Closes #27653.
Assisted-by: Claude Fable 5
-
90e010e3
by Simon Jakobi at 2026-08-14T12:54:21+02:00
testsuite: Make the deviation argument of collect_stats mandatory
Almost every caller passes an explicit tolerance matched to the
metric's noise profile, and the silent 20% default is far slacker than
'bytes allocated' merits. Only two tests relied on it. They now state
their tolerance explicitly:
large-project gets 10%, in line with other large compile-time tests.
T9848 gets 2%: its metric is byte-for-byte deterministic across CI
jobs and platforms of a given test_env, has drifted only about 2.5%
since 2015, and the fusion failure it guards against would show up as
a roughly +30000% jump.
Assisted-by: Claude Fable 5