-
bd3eba86
by Vladislav Zavialov at 2026-02-27T05:48:01-05:00
Check for negative type literals in the type checker (#26861)
GHC disallows negative type literals (e.g., -1), as tested by T8306 and
T8412. This check is currently performed in the renamer:
rnHsTyLit tyLit@(HsNumTy x i) = do
when (i < 0) $
addErr $ TcRnNegativeNumTypeLiteral tyLit
However, this check can be bypassed using RequiredTypeArguments
(see the new test case T26861). Prior to this patch, such programs
caused the compiler to hang instead of reporting a proper error.
This patch addresses the issue by adding an equivalent check in
the type checker, namely in tcHsType.
The diff is deliberately minimal to facilitate backporting. A more
comprehensive rework of HsTyLit is planned for a separate commit.
-
faf14e0c
by Vladislav Zavialov at 2026-02-27T05:48:45-05:00
Consistent pretty-printing of HsString, HsIsString, HsStrTy
Factor out a helper to pretty-print string literals, thus fixing newline
handling for overloaded string literals and type literals.
Test cases: T26860ppr T26860ppr_overloaded T26860ppr_tylit
Follow up to ddf1434ff9bb08cfef3c93f23de6b83ec698aa27
-
f108a972
by Arnaud Spiwack at 2026-02-27T12:53:01-05:00
Make list comprehension completely non-linear
Fixes #25081
From the note:
The usefulness of list comprehension in conjunction with linear types is dubious.
After all, statements are made to be run many times, for instance in
```haskell
[u | y <- [0,1], stmts]
```
both `u` and `stmts` are going to be run several times.
In principle, though, there are some position in a monad comprehension
expression which could be considered linear. We could try and make it so that
these positions are considered linear by the typechecker, but in practice the
desugarer doesn't take enough care to ensure that these are indeed desugared to
linear sites. We tried in the past, and it turned out that we'd miss a
desugaring corner case (#25772).
Until there's a demand for this very specific improvement, let's instead be
conservative, and consider list comprehension to be completely non-linear.
-
ae799cab
by Simon Jakobi at 2026-02-27T12:53:54-05:00
PmAltConSet: Use Data.Set instead of Data.Map
...to store `PmLit`s.
The Map was only used to map keys to themselves.
Changing the Map to a Set saves a Word of memory per entry.
Resolves #26756.
-
dcd7819c
by Vladislav Zavialov at 2026-02-27T18:46:03-05:00
Drop HsTyLit in favor of HsLit (#26862, #25121)
This patch is a small step towards unification of HsExpr and HsType,
taking care of literals (HsLit) and type literals (HsTyLit).
Additionally, it improves error messages for unsupported type literals,
such as unboxed or fractional literals (test cases: T26862, T26862_th).
Changes to the AST:
* Use HsLit where HsTyLit was previously used
* Use HsChar where HsCharTy was previously used
* Use HsString where HsStrTy was previously used
* Use HsNatural (NEW) where HsNumTy was previously used
* Use HsDouble (NEW) to represent unsupported fractional type literals
Changes to logic:
* Parse unboxed and fractional type literals (to be rejected later)
* Drop the check for negative literals in the renamer (rnHsTyLit)
in favor of checking in the type checker (tc_hs_lit_ty)
* Check for invalid type literals in TH (repTyLit) and report
unrepresentable literals with ThUnsupportedTyLit
* Allow negative type literals in TH (numTyLit). This is fine as
these will be taken care of at splice time (test case: T8306_th)
-
c927954f
by Vladislav Zavialov at 2026-02-27T18:46:50-05:00
Increase test coverage of diagnostics
Add test cases for the previously untested diagnostics:
[GHC-01239] PsErrIfInFunAppExpr
[GHC-04807] PsErrProcInFunAppExpr
[GHC-08195] PsErrInvalidRecordCon
[GHC-16863] PsErrUnsupportedBoxedSumPat
[GHC-18910] PsErrSemiColonsInCondCmd
[GHC-24737] PsErrInvalidWhereBindInPatSynDecl
[GHC-25037] PsErrCaseInFunAppExpr
[GHC-25078] PsErrPrecedenceOutOfRange
[GHC-28021] PsErrRecordSyntaxInPatSynDecl
[GHC-35827] TcRnNonOverloadedSpecialisePragma
[GHC-40845] PsErrUnpackDataCon
[GHC-45106] PsErrInvalidInfixHole
[GHC-50396] PsErrInvalidRuleActivationMarker
[GHC-63930] MultiWayIfWithoutAlts
[GHC-65536] PsErrNoSingleWhereBindInPatSynDecl
[GHC-67630] PsErrMDoInFunAppExpr
[GHC-70526] PsErrLetCmdInFunAppCmd
[GHC-77808] PsErrDoCmdInFunAppCmd
[GHC-86934] ClassPE
[GHC-90355] PsErrLetInFunAppExpr
[GHC-91745] CasesExprWithoutAlts
[GHC-92971] PsErrCaseCmdInFunAppCmd
[GHC-95644] PsErrBangPatWithoutSpace
[GHC-97005] PsErrIfCmdInFunAppCmd
Remove unused error constructors:
[GHC-44524] PsErrExpectedHyphen
[GHC-91382] TcRnIllegalKindSignature
-
3a9470fd
by Torsten Schmits at 2026-02-27T18:47:34-05:00
Avoid expensive computation for debug logging in `mergeDatabases` when log level is low
This computed and traversed a set intersection for every single
dependency unconditionally.
-
ea4c2cbd
by Brandon Chinn at 2026-02-27T16:22:38-08:00
Implement QualifiedStrings (#26503)
See Note [Implementation of QualifiedStrings]
-
08bc245b
by sheaf at 2026-03-01T11:11:54-05:00
Clean up join points, casts & ticks
This commit shores up the logic dealing with casts and ticks occurring
in between a join point binding and a jump.
Fixes #26642 #26929 #26693
Makes progress on #14610 #26157 #26422
Changes:
- Remove 'GHC.Types.Tickish.TickishScoping' in favour of simpler
predicates 'tickishHasNoScope'/'tickishHasSoftScope', as things were
before commit 993975d3. This makes the code easier to read and
document (fewer indirections).
- Introduce 'canCollectArgsThroughTick' for consistent handling of
ticks around PrimOps and other 'Id's that cannot be eta-reduced.
See overhauled Note [Ticks and mandatory eta expansion].
- New Note [JoinId vs TailCallInfo] in GHC.Core.SimpleOpt that explains
robustness of JoinId vs fragility of TailCallInfo.
- Allow casts/non-soft-scoped ticks to occur in between a join point
binder and a jump, but only in Core Prep.
See Note [Join points, casts, and ticks] and
Note [Join points, casts, and ticks... in Core Prep]
in GHC.Core.Opt.Simplify.Iteration.
Also update Core Lint to account for this.
See Note [Linting join points with casts or ticks] in GHC.Core.Lint.
- Update 'GHC.Core.Utils.mergeCaseAlts' to avoid pushing a cast in
between a join point binding and its jumps. This fixes #26642.
See the new (MC5) and (MC6) in Note [Merge Nested Cases].
- Update float out to properly handle source note ticks. They are now
properly floated out instead of being discarded.
This increases the number of ticks in certain tests with -g.
Test cases: T26642 and TrickyJoins.
Metric increase due to more source note ticks with -g:
-------------------------
Metric Increase:
libdir
size_hello_artifact
size_hello_unicode
-------------------------
-
476c4cdf
by Sean D. Gillespie at 2026-03-02T10:14:37-05:00
Add SIMD absolute value on x86 and LLVM
On x86, absolute value of 32 bits or less is implemented with
PABSB/PABSW/PABSD if SSSE3 is available. Otherwise, there is a fallback
for SSE2. For 64 bit integers it uses VPABSQ, required by AVX-512VL,
with fallbacks for SSE4.2 and SSE2.
There is no dedicated instruction for floating point absolute value on
x86, so it is simulated using bitwise AND.
Absolute value for signed integers and floats are implemented by the
"llvm.abs/llvm.fabs" standard library intrinsics. This implementation
uses MachOps constructors, unlike non-vector floating point absolute
value, which uses CallishMachOps.
-
709448c0
by Sean D. Gillespie at 2026-03-02T10:14:46-05:00
Add SIMD floating point square root
On x86, this is implemented with the SQRTPS and SQRTPD instructions. On
LLVM, it uses the sqrt library intrinstic.
-
0deadf66
by Sean D. Gillespie at 2026-03-02T10:14:47-05:00
Improve error message for SIMD on aarch64
When encountering vector literals on aarch64, previously it would
throw:
<no location info>: error:
panic! (the 'impossible' happened)
GHC version 9.15.20251219:
getRegister' (CmmLit:CmmVec):
Now it is more consistent with the other vector operations:
<no location info>: error:
sorry! (unimplemented feature or known bug)
GHC version 9.15.20251219:
SIMD operations on AArch64 currently require the LLVM backend
-
7d64031b
by Vladislav Zavialov at 2026-03-03T11:09:28-05:00
Replace maybeAddSpace with spaceIfSingleQuote
Simplify pretty-printing of HsTypes by using spaceIfSingleQuote.
This allows us to drop the unwieldy lhsTypeHasLeadingPromotionQuote
helper function.
Follow-up to 178c1fd830c78377ef5d338406a41e1d8eb5f0da
-
598db847
by Wolfgang Jeltsch at 2026-03-06T06:25:25-05:00
Correct `hIsReadable` and `hIsWritable` for duplex handles
This contribution implements CLC proposal #371. It changes `hIsReadable`
and `hIsWritable` such that they always throw a respective exception
when encountering a closed or semi-closed handle, not just in the case
of a file handle.
-
b90201e5
by Wolfgang Jeltsch at 2026-03-06T06:25:25-05:00
Document `SemiClosedHandle`
-
c9df72b5
by Wolfgang Jeltsch at 2026-03-06T06:25:25-05:00
Tell users what “semi-closed” means for duplex handles
-
a8aa1868
by Ilias Tsitsimpis at 2026-03-06T06:26:29-05:00
Fix determinism of linker arguments
The switch from Data.Map to UniqMap in 3b5be05ac29 introduced
non-determinism in the order of packages passed to the linker.
This resulted in non-reproducible builds where the DT_NEEDED entries in
dynamic libraries were ordered differently across builds.
Fix the regression by explicitly sorting the package list derived from
UniqMap.
Fixes #26838
-
9b64ad3a
by Matthew Pickering at 2026-03-06T06:27:16-05:00
determinism: Use a deterministic renaming when writing bytecode files
Now when writing the bytecode file, a counter and substitution are used
to provide deterministic keys to local variables (rather than relying on
uniques). This change ensures that `.gbc` are produced
deterministically.
Fixes #26499
-
d29800e0
by Teo Camarasu at 2026-03-06T06:28:46-05:00
ghc-internal: delete Version hs-boot loop
Version has a Read instance which needs Unicode but part of the Unicode interface is the unicode version. This is easy to resolve. We simply don't re-export the version from the Unicode module.
Resolves #26940
-
ad25af90
by Sylvain Henry at 2026-03-06T06:30:33-05:00
Linker: implement support for COMMON symbols (#6107)
Add some support for COMMON symbols. We don't support common symbols
having different sizes where the larger one is allocated after the
smaller one. The linker will fail with an appropriate error message if
it happens.
-
3b59f158
by Cheng Shao at 2026-03-06T06:31:16-05:00
compiler: fix redundant import of GHC.Hs.Lit
This patch removes a redundant import of `GHC.Hs.Lit` which causes a
ghc build failure with validate flavours when bootstrapping from 9.14.
Fixes #26972.
-
148d36f3
by Cheng Shao at 2026-03-06T06:32:01-05:00
compiler: avoid unneeded traversals in GHC.Unit.State
Following !15591, this patch avoids unneeded traversals in
`reportCycles`/`reportUnusable` when log verbosity is below given
threshold. Also applies `logVerbAtLeast` when appropriate.
Co-authored-by: Codex <codex@openai.com>
-
7e31367c
by Cheng Shao at 2026-03-06T06:32:46-05:00
ghc-internal: fix redundant import in GHC.Internal.Event.Windows.ManagedThreadPool
This patch fixes redundant import in
`GHC.Internal.Event.Windows.ManagedThreadPool` that causes a
compilation error when building windows target with validate flavours
and bootstrapping from 9.14. Fixes #26976.
-
fc8b8e27
by sheaf at 2026-03-06T06:33:28-05:00
System.Info.fullCompilerVersion: add 'since' annot
Fixes #26973
-
c8238375
by Sylvain Henry at 2026-03-06T06:34:23-05:00
Hadrian: deprecate --bignum and automatically enable +native_bignum for JS
Deprecate --bignum=... to select the bignum backend. It's only used to
select the native backend, and this can be done with the +native_bignum
flavour transformer.
Additionally, we automatically enable +native_bignum for the JS target
because the GMP backend isn't supported.
-
a3ac7074
by Sylvain Henry at 2026-03-06T06:35:17-05:00
JS: fix putEnum/fromEnum (#24593)
Don't go through Word16 when serializing Enums.
-
0b36e96c
by Andreas Klebinger at 2026-03-06T06:35:58-05:00
Docs: Document -fworker-wrapper-cbv default setting.
Fixes #26841
-
eca445e7
by mangoiv at 2026-03-07T05:02:36-05:00
drop deb9/10 from CI, add deb13
debian 9 and 10 are end of life, hence we drop them
from our CI, but we do add debian 13. Jobs that were
previously run on 9 and 10 run on 13, too, jobs that
were run on 10, are run on 11 now. Jobs that were
previously run on debian 12 are run on debian 13 now.
This MR also updates hadrian's bootstrap plans for that
reason.
Metric Decrease:
T9872d
-
12f8b829
by Luite Stegeman at 2026-03-07T05:03:33-05:00
Fix GHC.Internal.Prim haddock
Haddock used to parse Haskell source to generate documentation,
but switched to using interface files instead. This broke documentation
of the GHC.Internal.Prim module, since it's a wired-in interface that
didn't provide a document structure.
This patch adds the missing document structure and updates genprimopcode
to make the section headers and descriptions available.
fixes #26954
-
f87e5e57
by Luite Stegeman at 2026-03-07T05:03:33-05:00
Remove obsolete --make-haskell-source from genprimopcode
Now that haddock uses the wired-in interface for GHC.Internal.Prim,
the generated Haskell source file is no longer needed. Remove the
--make-haskell-source code generator from genprimopcode and replace
the generated GHC/Internal/Prim.hs with a minimal static source file.
-
4a7ddc7b
by Sylvain Henry at 2026-03-07T05:04:59-05:00
JS: fix linking of exposed but non-preload units (#24886)
Units exposed in the unit database but not explicitly passed on the
command-line were not considered by the JS linker. This isn't an issue
for cabal which passes every unit explicitly but it is an issue when
using GHC directly (cf T24886 test).
-
689aafcd
by mangoiv at 2026-03-07T05:05:52-05:00
testsuite: double foundation timeout multiplier
The runtime timeout in the foundation test was regularly hit by code
generated by the wasm backend - we increase the timout since the high
runtime is expected on the wasm backend for this rather complex test.
Resolves #26938
-
f2bfed15
by Apoorv Ingle at 2026-03-08T16:08:46-05:00
Work for #25001
Notes added [Error Context Stack] [Typechecking by expansion: overview]
Notes updated Note [Expanding HsDo with XXExprGhcRn]
-------------------------
Metric Decrease:
T9020
-------------------------
* Streamlines implementations of `tcExpr` and `tcXExpr` to work on `XExpr`
* Kills `VACtxt` (and its associated `VAExpansion` and `VACall`) datatype, it is subsumed by simply a `SrcSpan`.
* Kills the function `addHeadCtxt` as it is now mearly setting a location
* The function `tcValArgs` does its own argument number management
* Makes `splitHsApps` not look through `XExpr`
* `tcExprSigma` is called if the head of the expression after calling `splitHsApps` turns out to be an `XExpr`
* Removes location information from `OrigPat` payload
* Removes special case of tcBody from `tcLambdaMatches`
* Removes special case of `dsExpr` for `ExpandedThingTc`
* Rename `HsThingRn` to `SrcCodeCtxt`
* Kills `tcl_in_gen_code` and `tcl_err_ctxt`. It is subsumed by `ErrCtxtStack`
* Kills `ExpectedFunTyOrig`. It is subsumed by `CtOrigin`
* Fixes `CtOrigin` for `HsProjection` case in `exprCtOrigin`. It was previously assigned to be `SectionOrigin`. It is now just the expression
* Adds a new `CtOrigin.ExpansionOrigin` for storing the original syntax
* Adds a new `CtOrigin.ExpectedTySyntax` as a replacement for `ExpectedTySyntaxOp`. Cannot kill the former yet because of `ApplicativeDo`
* Renames `tcMonoExpr` -> `tcMonoLExpr`, `tcMonoExprNC` -> `tcMonoLExpr`
* Renames `EValArg`, `EValArgQL` fields: `ea_ctxt` -> `ea_loc_span` and `eaql_ctx` -> `eaql_loc_span`
* kill `PopErrCtxt` from `XXExprGhcRn`
* simplify `addArgCtxt` and push `setSrcSpan` inside `addLExprCtxt`. Make sure addExprCtxt is not called by itself
* fun_orig in tcApp depends on the SrcSpan of the head of the application chain (similar to addArgCtxt)
* rename fun_ctxt to fun_lspan, fun_orig passed in tcInstFun to default to app chain head if its user located, fall back to srcCodeOrigin if it's a generated location
* fix quickLookArg function to blame the correct application chain head. The arguments application chain head should be blamed, not the original head when we quick look arg
* Make sure only expression wrapped around generated src span are ignored while adding them to the error context stack
* `getDeepSubsumptionFlag_DataConHead` performs a non-trivial traversal if the expression passed to it is complex.
This traversal is necessary if the head of the function is an `XExpr` and `splitHsApps` does not look through them
- The deepsubsumption flag is stored in EVAlArgQL to reduce the need to call `getDeepSubsumptionFlag_DataConHead`
- `getDeepSubsumptionFlag_DataConHead` is called in `tcExprSigma` and `tcInferAppHead` to reduce AST traversals
* Make a new variant `GeneratedSrcSpan` in `SrcSpan` for HIEAst Nodes
* wrap `fromListN` with a generated src span with GeneratedSrcSpanDetails field to store the original srcspan
* remove `UnhelpfulGenerated` from `UnhelpfulSpanReason` and into new datatype `GeneratedSrcSpanDetails`
-
466e162c
by Apoorv Ingle at 2026-03-08T16:11:02-05:00
trying to remove SrcCodeOrigin
-
2949e4c3
by Simon Peyton Jones at 2026-03-08T16:11:03-05:00
Improvements in ErrCtxt
-
5ed13f95
by Apoorv Ingle at 2026-03-08T16:11:04-05:00
ErrCtxtMsg to CtOrigin
-
b7beec74
by Apoorv Ingle at 2026-03-08T16:11:05-05:00
remove CtOrigin.ExpansionOrigin in favour of errCtxtCtOrigin, remove CtOrign from ErrMsgCtxt.FunTysCtxt