-
17839248
by Teo Camarasu at 2026-02-24T08:36:03-05:00
ghc-internal: avoid depending on GHC.Internal.Control.Monad.Fix
This module contains the definition of MonadFix, since we want an
instance for IO, that instance requires a lot of machinery and we want
to avoid an orphan instance, this will naturally be quite high up in the
dependency graph.
So we want to avoid other modules depending on it as far as possible.
On Windows, the IO manager depends on the RTSFlags type, which
transtively depends on MonadFix. We refactor things to avoid this
dependency, which would have caused a regression.
Resolves #26875
Metric Decrease:
T12227
-
fa88d09a
by Wolfgang Jeltsch at 2026-02-24T08:36:47-05:00
Refine the imports of `System.IO.OS`
Commit 68bd08055594b8cbf6148a72d108786deb6c12a1 replaced the
`GHC.Internal.Data.Bool` import by a `GHC.Internal.Base` import.
However, while the `GHC.Internal.Data.Bool` import was conditional and
partial, the `GHC.Internal.Base` import is unconditional and total. As a
result, the import list is not tuned to import only the necessary bits
anymore, and furthermore GHC emits a lot of warnings about redundant
imports.
This commit makes the `GHC.Internal.Base` import conditional and partial
in the same way that the `GHC.Internal.Data.Bool` import was.
-
c951fef1
by Cheng Shao at 2026-02-25T20:58:28+00:00
wasm: add /assets endpoint to serve user-specified assets
This patch adds an `/assets` endpoint to the wasm dyld http server, so
that users can also fetch assets from the same host with sensible
default MIME types, without needing a separate http server for assets
that also introduces CORS headaches:
- A `-fghci-browser-assets-dir` driver flag is added to specify the
assets root directory (defaults to `$PWD`)
- The dyld http server fetches `mime-db` on demand and uses it as
source of truth for mime types.
Closes #26951.
-
dde22f97
by Sylvain Henry at 2026-02-26T13:14:03-05:00
Fix -fcheck-prim-bounds for non constant args (#26958)
Previously we were only checking bounds for constant (literal)
arguments!
I've refactored the code to simplify the generation of out-of-line Cmm
code for the primop composed of some inline code + some call to an
external Cmm function.
-
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
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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
-------------------------
-
0da8a5d0
by Fendor at 2026-03-02T12:31:32+01:00
Add `-fwin-aware-long-paths` to support ling paths on Windows
While Windows supports file paths longer than the MAX_PATH restriction,
it is opt-in, and not enabled by default.
By declaring the binary to be long path aware in the manifest of the
windows executable, the binary opts-in to the new behaviour.
It is up to the developer to make sure they use UNC paths and Win.h
specific functions for filesystem operations to use long paths in their
application.
See
https://learn.microsoft.com/en-us/windows/win32/fileio/maximum-file-path-limitation#application-manifest-updates-to-declare-long-path-capability
and https://learn.microsoft.com/en-us/windows/win32/sbscs/application-manifests
for the documentation on the application manifest and long path option.