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[Git][ghc/ghc][wip/sol/dont-use-global-variables] 108 commits: Introduce a cache of home module name providers
by Simon Hengel (＠sol) 22 Jun '26

22 Jun '26

Simon Hengel pushed to branch wip/sol/dont-use-global-variables at Glasgow Haskell Compiler / GHC Commits: 5fab2238 by Wolfgang Jeltsch at 2026-05-12T21:24:27+03:00 Introduce a cache of home module name providers This contribution introduces to the module graph a cache that maps home module names to sets of units providing them and changes the finder to use that cache. This is a performance optimization, especially for multi-home-unit builds. The particular changes are as follows: * In `GHC.Unit.Module.Graph`, `ModuleGraph` is extended with a new field `mg_home_module_name_providers_map`, exposed as `mgHomeModuleNameProvidersMap`. This is a cache that assigns to each home module name the set of IDs of home units that define it. Operations that construct module graphs are updated such that this cache stays synchronized. * In `GHC.Unit.Finder`, `findImportedModule` is changed to pull `mgHomeModuleNameProvidersMap` from `hsc_mod_graph` and pass it to `findImportedModuleNoHsc`, which now does not search home units in arbitrary order but prioritizes those units that the cache mentions as potential providers of the requested module. In addition, this contribution adds variants of the two multi-component compiler performance tests that use 100 units instead of 20, because with just 20 units the benefits from caching of home module name providers are still negligible. The following table shows the total time needed for running both multi-component tests before and after this contribution and with different numbers of units: | # of units | Before | After | |-----------:|-------:|------:| | 20 | 0:12 | 0:12 | | 100 | 0:47 | 0:42 | | 200 | 3:05 | 2:08 | Note that there seems to be a general overhead of 12 seconds that is not attributable to the actual tests, so that the real running times should be 12 seconds smaller than shown above. Resolves #27055. Metric Decrease: MultiComponentModules MultiComponentModulesRecomp Co-authored-by: Matthew Pickering <matthewtpickering(a)gmail.com> Co-authored-by: Fendor <fendor(a)posteo.de> - - - - - 38b76b2f by Cheng Shao at 2026-05-13T17:48:48-04:00 testsuite: mark T22159 as fragile This patch marks T22159 as fragile on Windows for issue described in #27248. Before we get to the bottom of those failures, this unblocks newer Windows runners. - - - - - 50188615 by Ian Duncan at 2026-05-14T13:45:07+02:00 AArch64: use ASR not LSR for MO_U_Shr at W8/W16 The unsigned right shift (MO_U_Shr) for sub-word widths (W8, W16) with a variable shift amount was emitting ASR (arithmetic/signed shift right) after zero-extending with UXTB/UXTH. This should be LSR (logical/unsigned shift right). After zero-extension the upper bits happen to be 0 so ASR produces the same result, but it is semantically wrong and would break if the zero-extension were ever optimized away. Includes assembly output test (grep for lsr) and runtime test verifying unsigned right shift of Word8 and Word16 values. - - - - - 28666fbf by Vladislav Zavialov at 2026-05-19T12:44:05-04:00 Add type families: Tuple, Constraints, Tuple#, Sum# (#27179) These type families map tuples of types to the corresponding Tuple<N>, Tuple<N>#, CTuple<N>, and Sum<N># types. Some examples at N=2: Tuple (Int, Bool) = Tuple2 Int Bool Constraints (Show a, Eq a) = CTuple2 (Show a) (Eq a) Tuple# (Int#, Float#) = Tuple2# Int# Float# Sum# (Int#, Float#) = Sum2# Int# Float# See GHC Proposal #145 "Non-punning list and tuple syntax". To make the Sum# instance at N=64 possible, this patch also introduces the Sum64# constructor declaration and bumps mAX_SUM_SIZE from 63 to 64. Metric Increase: ghc_experimental_dir - - - - - 41c2448b by Wen Kokke at 2026-05-19T12:44:53-04:00 rts: Add IPE event class for -l This commit adds a new IPE event class to the -l RTS flag. Previously, IPE events were enabled unconditionally. However, the IPE events can easily grow to hundreds or thousands of megabytes. With the new event class you can pass, e.g., -l-I to disable IPE events. - - - - - 62536551 by Wen Kokke at 2026-05-19T12:44:53-04:00 ghc-internal: Add TraceFlags.traceIPE - - - - - e45312d1 by Wen Kokke at 2026-05-19T12:44:53-04:00 testsuite: Add test for TraceFlags.traceIpe - - - - - 4768d9aa by Wen Kokke at 2026-05-19T12:44:53-04:00 ghc-internal: Add DebugFlags.ipe - - - - - bc1b5c69 by Wen Kokke at 2026-05-19T12:44:53-04:00 testsuite: Add test for DebugFlags.ipe - - - - - 0da1543f by Duncan Coutts at 2026-05-19T12:45:37-04:00 Document removal of the signal-based interval timer Update mentions within the RTS section of the users guide. Add a changelog entry. - - - - - b2911514 by Duncan Coutts at 2026-05-19T12:45:37-04:00 Fix section for an recent changelog entry - - - - - d6d76a7a by David Eichmann at 2026-05-19T12:46:19-04:00 ghc-toolchain: implement llvm program versioning logic - - - - - 2dd36fa3 by Wolfgang Jeltsch at 2026-05-20T04:49:52-04:00 Turn `Trustworthy` into `Safe` in `base` where possible - - - - - f4399dd1 by Wolfgang Jeltsch at 2026-05-20T04:50:37-04:00 Make the current `base` buildable with GHC 10.0 - - - - - 1a7de232 by Duncan Coutts at 2026-05-20T12:26:25-04:00 Hadrian: remove legacy rts .so symlinks For compatibility with the old makefile based build system, hadrian had rules to generate symlinks from unversioned to versioned names for the rts .so/.dynlib file, like libHSrts-ghcx.y.so -> libHSrts-1.0.3-ghcx.y.so We no longer need these symlinks since the makefile build system has been retired some time ago. The need for these symlinks is awkward on windows where we cannot (in practice) create symlinks. So rather than make them conditional (non-windows), just remove them entirely. - - - - - 286f1adf by fendor at 2026-05-20T12:27:09-04:00 Fix regression T27202: `:load` and `:add` work in GHCi To fix the regression there are conceptually two major things that we fix: * We don't remove the `importDirs` from `interactive-session` * When `:add`ing a module, we don't try to find them via PackageImports * The PackageImport is wrong as we can't know the package-name at this stage in ghc/UI.hs What does it mean to not remove the `importDirs` from `interactive-session`? It means that, given some initial `DynFlags`, we will use those `importDirs` in `interactive-session`. The initial `DynFlags`, however, depend on how you initialise the GHC session. For a simple session, initialised by ghc -isrc -this-unit-id main It is simple, just use the `DynFlags` given on the cli. Thus, `main` and `interactive-session` will have the same `DynFlags`, except for the `homeUnitId` and `interactive-session` depends on `main` by construction of the GHCi session. What about a multiple home unit session, though? ghc -unit @unit1 -unit @unit2 What are the `DynFlags` in this cli invocation? It shouldn't be either `@unti1` nor `@unit2`, as the order shouldn't matter or any other implicit condition. For consistency, we decide that the initial `DynFlags` are the top `DynFlags` on the cli, ignoring `-unit` flags. Thus, in this example, there are no `importsDirs` regardless of what we might find in `@unit1` and `@unit2`. But in this invocation: ghc -isrc -unit @unit1 -unit @unit2 The `interactive-session` will have the `importsDirs` `src`. Note, `-isrc` will be inherited in `@unit1` and `@unit2`, so you need to explicitly use `-i` to clear the `importsDirs`, in order to avoid accidentally adding `src` as an import directory to all other home units. This fix has been made possible by the improvements introduced in !15888, which avoids ambiguity when a home unit shares the `importsDirs` with the `interactive-session`, on top of being much faster for multiple home units. Adds regression tests for T27202 for `:load`ing and `:add`ing modules that are located in import directories. - - - - - 728662de by fendor at 2026-05-20T12:27:09-04:00 Use home unit package db stacks in GHCi prompt and session unit In order to import modules from home unit dependencies (e.g., `Data.Map`), the ghci prompt unit needs to populate its `UnitState`. This is tricky to handle correctly, which `PackageDBFlag`s should we use to populate the `UnitState`? We decide, the most intuitive solution for users is to depend on all `PackageDBFlag`s, so that any dependency can be imported in GHCi. This assumes consistency in the `PackageDBFlag`s, so no two home units specify `PackageDBFlag`s that are inconsistent with each other. We could simply concat all the `PackageDBFlag`s of the existing home units, but later `PackageDBFlag`s shadow earlier ones, leading to the last processed home units' `PackageDBFlag`s to shadow the earlier ones. This is hard to fix, we need to give users the capability to provide ghc options for the ghci prompt home unit. However, as this is considerably more work, we decided on an approximation that should work out most of the time. Package Db stacks in cabal and stack follow a certain structure: -no-user-package-db > -package-db $cabal-store > -package-db $local-db The first two arguments are always the same, namely the `-no-user-package-db` and `-package-db`. We compute the longest common prefix over all home units, and use that as the start of the package db stack. Then, over the rest of the `PackageDBFlag`s, we simply take the union and append them to our initial stack. We assume, that the rest of package dbs only defines very few, "local" units that are usually not shadowing each other. This allows us to get a relatively consistent package database stack for the ghci prompt home unit. Similar reasoning applies to the session unit in order to add modules to the session and have dependencies available in the module. We do something similar for `-package` flags, to make sure only the correct units are actually visible in the ghci session. This time, we simply take the union of all `PackageFlag`s, allowing us to import modules from the home unit dependencies. In the future, it would be beneficial to allow the user to provide the exact ghc options to control the visibilities. For now, this will have to do. - - - - - 740d89a0 by Simon Peyton Jones at 2026-05-20T17:20:44-04:00 Do not use mkCast during typechecking This commit fixes #27219. The problem was that the typechecker was using `mkCast`, whose assertion checks legitimately fail when applied to types that contain unification variables. - - - - - a50fdb06 by Simon Peyton Jones at 2026-05-20T17:20:45-04:00 Major refactor of the Simplifier The main payload of this patch is to refactor the Simplifer to avoid repeated simplification when using Plan (AFTER) for rule rewrites. The need for this was shown up by #26989. See Note [Avoid repeated simplification] in GHC.Core.Opt.Simplify.Iteration. Related refactoring: * Refactor the two fields `sc_dup` and `sc_env` in `ApplyToVal` into one, `sc_env`. Reason: the envt is irrelevant in the "simplified" case, so the data type describes the possiblitiies much more accurately now. * Some refactoring in `knownCon` to split off `wrapDataConFloats`. * Refactor `lookupRule` and its auxiliary functions to return `RuleMatch`, a new data type. See Note [data RuleMatch] in GHC.Core. Ditto for BuiltinRule. This RuleMatch returns fragments of the target in rm_args and rm_floats, leaving `rm_rhs` to be the stuff from the RULE itself. Doing this has routine consequences in GHC.Core.Opt.ConstantFold. Many changes there but all routine. * When doing occurrence analysis on RULEs, make the occ-info on the rule binders relate just to the RHS, not the LHS. See (OUR1) in Note Note [OccInfo in unfoldings and rules] This means that Lint must not complain about the fact that the patterns in the RULE mentions binders that are marked dead. See Note [Dead occurrences] in GHC.Core.Lint. I changed the Core pretty-printer so that it didn't suppress dead binders, else I can't see those binders in RULEs. That led to quite a lot of testsuite wibbles. * Refactor FloatBinds, so that it is used both by `exprIsConApp_mabye` and by `lookupRule` * Move the definition of FloatBinds out of GHc.Core.Make, into GHC.Core. * Add FloatTick as an extra constructor. * Refactor `lookupRule` to use `FloatBinds` instead of `BindWrapper`. This refactor just shares more code. (Rename GHC.Core.Opt.FloatOut.FloatBinds to FloatLets, to avoid gratuitious name clash with GHC.Core.FloatBinds.) Corecion optimisation * In simpleOpt, when composing coercions, call new function `optTransCo`. This is much lighter weight than full blown coercion optimisation. * Make `GHC.Core.Opt.Arity.pushCoValArg` and `pushCoTyArg` return the coercionLKind of the coercion. This saves recomputing that coercionLKind at the key call sites in GHC.Core.Opt.Simplify.Iteration.pushCast. * Rename `addCoerce` in GHC.Core.Simplify.Iteration to become `pushCast`. * In the `ApplyToVal` case of `pushCast` we had a very unsavoury call to `simplArg`. I eliminated it by adding a field `sc_cast` to `ApplyToVal` that records any pending casts. Much nicer now. See Note [The sc_cast field of ApplyToVal]. * Don't optimise coercions if the type-substitution is empty. See Note [Optimising coercions] in GHC.Core.Opt.Simplify.Iteration. The fix for #26838 is dramatic. For the test in perf/compiler/T26839 we have Compiler allocs: Before: 7,363M After: 688M Compile time goes down generally. Here are compiler-alloc changes over 0.5%: CoOpt_Read(normal) 729,184,920 -0.7% CoOpt_Singletons(normal) 666,916,960 -4.6% GOOD LargeRecord(normal) 1,227,056,876 +1.1% T12227(normal) 256,827,604 -4.6% GOOD T12425(optasm) 76,879,410 -0.8% T12545(normal) 787,826,918 -10.8% GOOD T12707(normal) 775,186,464 -0.9% T13253(normal) 318,599,596 -0.8% T14766(normal) 685,857,320 -1.0% T15304(normal) 1,123,333,422 -2.2% T15630(normal) 123,142,330 -2.6% T15630a(normal) 123,092,100 -2.6% T15703(normal) 299,751,682 -2.9% GOOD T17516(normal) 964,072,280 +1.0% T18223(normal) 367,016,820 -6.2% GOOD T18730(optasm) 130,643,770 -3.3% GOOD T20261(normal) 535,608,584 -0.7% T21839c(normal) 340,340,436 -0.9% T24984(normal) 85,568,392 -1.9% T3064(normal) 174,631,992 -1.2% T3294(normal) 1,215,886,432 -0.7% T5030(normal) 141,449,704 -17.2% GOOD T5321Fun(normal) 258,484,744 -1.9% T8095(normal) 770,532,232 -2.7% T9630(normal) 858,423,408 -14.5% GOOD T9872c(normal) 1,591,709,448 +0.7% info_table_map_perf(normal) 19,700,614,458 -1.3% geo. mean -0.7% minimum -17.2% maximum +1.1% However, strangely there seems to be a 5.0% increase in CoOpt_Read in the x86_64-linux-fedora43-validate+debug_info+ubsan job, although there generally a /decrease/ in this test in other builds. The baseline value looks strange. Anyway I'll just accept it. Metric Decrease: CoOpt_Singletons T12227 T12545 T12707 T15703 T18223 T18730 T21839c T5030 T9630 Metric Increase: CoOpt_Read - - - - - 834623d4 by Mrjtjmn at 2026-05-20T17:21:41-04:00 users-guide: Fix weird notation in "Summary of stolen syntax" - - - - - 6f9d7c71 by Markus Läll at 2026-05-21T15:25:34-04:00 Use "grimily" instead of "grimly" Fixes https://gitlab.haskell.org/ghc/ghc/-/issues/27221 - - - - - 50e999ca by fendor at 2026-05-21T15:26:18-04:00 Speed up 'closure' computation in `ghc-pkg` Cache the set of already seen `UnitId`s and use `Set` operations to speed up 'closure' computation. Further simplify the implementation of 'closure' to account for the actual usage. As a consequence, we rename 'closure' to 'brokenPackages' to reflect its purpose better after the simplification. - - - - - 7ecc6184 by sheaf at 2026-05-21T15:27:10-04:00 TcMPluginHandling: be more lenient when no plugins This change ensures that, if a function such as 'typecheckModule' was invoked with 'NoTcMPlugins', GHC doesn't spuriously complain about TcM plugins having already been stopped, as there were none to start with. - - - - - 72c8de5c by Simon Jakobi at 2026-05-23T18:41:42-04:00 Implement List.elem via foldr ...in order to allow specialization to Eq instances. The implementation of notElem is updated for consistency.` Corresponding CLC proposal: https://github.com/haskell/core-libraries-committee/issues/412 Addresses #27096. - - - - - 3268c610 by Alan Zimmerman at 2026-05-23T18:42:30-04:00 EPA: Fix span for qualified multiline string Fix the span for a qualified multiline string like Text.""" I'm a multiline Text value ! """ to extend to the end of the entire string, not just the first line. Closes #27274 - - - - - 1f096790 by Alan Zimmerman at 2026-05-23T18:43:20-04:00 EPA: Fix exact printing namespace-specified wildcards Ensures correct printing of imports of the form import Data.Bool (data True(data ..)) import Data.Bool (data True(type ..)) Closes #27291 - - - - - 56ada7c0 by Mrjtjmn at 2026-05-23T18:44:19-04:00 Fix ambiguous syntax of BangPatterns in users guide Update documentation for the BangPatterns extension to specify how surrounding whitespace affects interpretation of `!`. * Only when there is whitespace before `!` and no whitespace after, it is recognized as a BangPattern. * Other cases `⟨varid⟩!⟨varid⟩`, `⟨varid⟩ ! ⟨varid⟩`, `⟨varid⟩! ⟨varid⟩` are treated as infix operators. - - - - - 579aa0b7 by Simon Jakobi at 2026-05-25T16:31:26-04:00 Ensure that SetOps.{minusList,unionListsOrd} can be specialized ...by marking them INLINABLE. Haddock allocates 0.1–0.3% less as a result. This also removes some redundant constraints on unionListsOrd. - - - - - cccf45da by Cheng Shao at 2026-05-25T16:32:13-04:00 wasm: ensure post-linker output is synchronous ESM This patch fixes wasm backend's post-linker output script to ensure it's synchronous ESM and doesn't use top-level await, which doesn't work in ServiceWorkers. Fixes #27257. - - - - - 8db331a3 by Zubin Duggal at 2026-05-26T04:54:03-04:00 Update to semaphore-compat 2.0.0 using v2 of the protocol On Linux and other POSIX platforms, GHC's -jsem jobserver client now speaks v2 of the semaphore-compat protocol, which uses Unix domain sockets in place of POSIX named semaphores. This avoids the libc-ABI issues that affected the old implementation. Windows is unaffected and continues to use the v1 protocol (Win32 named semaphores); its reported protocol version remains v1. When GHC receives a -jsem name whose protocol version it does not support, it emits a -Wsemaphore-version-mismatch warning and falls back to -j<N> rather than crashing. ghc --info exposes the supported version in a new "Semaphore version" entry so cabal-install can detect a mismatch before invoking GHC. Users on a cabal-install that predates the v2 update will continue to build successfully on Linux/POSIX, but will lose the cross-process -jsem coordination and fall back to -j<N> per GHC invocation. Users must upgrade to a cabal-install that supports protocol v2 to recover full parallelism. Also fix a leak in cleanupSem (#27253): cleanupSem used to snapshot heldTokens and release them before killing the loop, while the loop's in-flight acquire/release children could still be mutating it. Cleanup now runs inside the loop's own exit handler, after draining the active child via a new activeChild TVar, so the snapshot has no concurrent mutator. See also: - GHC proposal amendment: https://github.com/ghc-proposals/ghc-proposals/pull/673 - cabal-install patch: https://github.com/haskell/cabal/pull/11628 - semaphore-compat MR: https://gitlab.haskell.org/ghc/semaphore-compat/-/merge_requests/8 Bump semaphore-compat submodule to 2.0.0 Fixes #25087 and #27253 - - - - - 17be4f1f by Alan Zimmerman at 2026-05-26T04:54:52-04:00 EPA: Record semicolons in HsModifier Ensure the semi colons are captured in the ParsedSource for code like %True;; %False; instance C D It makes HsModifier (and hence HsModifierOf) LocatedA, so the semi colons can be recorded as [TrailingAnn] Also rename pprHsModifiers to pprLHsModifiers to match. Closes #27294 - - - - - 8f991755 by fendor at 2026-05-26T11:02:52-04:00 Revert prog003 acceptance We thought the commit 286f1adff3e78d775ff325caff71d0cee25d710b fixed the test, but due to changes to ghci, modules loaded during the GHCi session, the test was actually no longer testing what it set out to do, "fixing" the broken test. As modules are added to the `interactive-session` home unit, the object code needs to be compiled with `-this-unit-id interactive-session`, otherwise the object code won't be used. Once this has been fixed in the test, the test fails as expected again. - - - - - 277a3687 by mangoiv at 2026-05-26T11:03:40-04:00 libraries/process: bump submodule to v1.6.29.0 This submodule bump resolves a segfault on macos 15. Fixes #27144 - - - - - 6779bb0c by mangoiv at 2026-05-26T11:03:40-04:00 libraries/unix: in submodule, don't pick branch 2.7 The 2.7 branch is outdated and the module has been advanced far beyond it anyway, so remove that line. - - - - - 4a645683 by Simon Peyton Jones at 2026-05-27T21:41:59-04:00 Trim the continuation in mkDupableContWithDmds When there are no remaining argument demands, it means the application is bottoming. In this case, we can trim the continuation to avoid the panic that was observed in #27261. See Note [Trimming the continuation for bottoming functions] in GHC.Core.Opt.Simplify.Iteration. - - - - - 8ab506ff by Cheng Shao at 2026-05-27T21:42:47-04:00 ghci: fix module name string lifetime in hs_hpc_module invocation This patch makes hpcAddModule pass a properly malloced module name string to hs_hpc_module, instead of using useAsCString which causes use-after-free of module name string. Fixes #27297. Co-authored-by: Codex <codex(a)openai.com> - - - - - b0233814 by sheaf at 2026-05-27T21:43:31-04:00 Relax acceptance threshold for T10421 As seen in #27289, the 1% acceptance threshold for this text was overly narrow, resulting in spurious test failures. This commit widens the acceptance threshold to 2%. Fixes #27289. - - - - - 63ce5770 by Luite Stegeman at 2026-05-28T12:23:35-04:00 Fixes for black holes - suspend duplicate work for eager black holes - detect eager black holes in checkBlockingQueues - don't overwrite existing black holes even if they're not in an eager blackhole frame - don't deadlock on self when thunk is already blackholed Fixes #26936 - - - - - 037a80dc by Tom McLaughlin at 2026-05-28T12:24:36-04:00 Event/Windows.hsc: rethrow exceptions in overlapped IO This prevents the WinIO manager from swallowing exceptions in overlapped IO. It was added to make WinIO support possible in the `network` library. See https://gitlab.haskell.org/ghc/ghc/-/issues/27283. We also bump __IO_MANAGER_WINIO__ to 2 so libraries can gate on this using CPP. - - - - - 2d53bcdb by Wolfgang Jeltsch at 2026-05-28T12:25:21-04:00 Allow `downsweep` to use nodes of an existing module graph To this end, `downsweep` has not been able to use the nodes of a module graph obtained from a previous downsweeping round. In some GHC API applications, downsweeping is performed somewhat incrementally and therefore could profit from reusing such existing results. This contribution makes this possible. Resolves #27054. Co-authored-by: Matthew Pickering <matthewtpickering(a)gmail.com> - - - - - f4fbb583 by Simon Jakobi at 2026-05-28T12:26:04-04:00 Add regression test for T11226 Closes #11226. - - - - - ed29a5e6 by Sven Tennie at 2026-05-28T17:30:36-04:00 Add optional config setting for LibDir (#19174) Previously, the `libDir` was derived from `topDir`. This won't work for inplace stage2 cross-compilers where binaries and libraries are in different stage dirs (`_build/stage1/` for executables and `_build/stage2` for libraries). `LibDir` is set in the inplace `settings` files. For bindists, we generate a new `settings` file with no `LibDir` entry. GHC then defaults to use `topDir` as `libDir` again. This keeps the bindist relocatable. If `LibDir` is a relative path, it is interpreted relatively to `topDir`. The global package db is part of the `lib/` folder. If we want to point for inplace cross-compilers to the succeeding stage's folder, this is done by setting `LibDir`. Thus, the global package db must be found relative to `libDir`` (which may default to `topDir` or be set by `LibDir`). The complexity of settings becomes scary. So, add a test to ensure `LibDir` works as expected. - - - - - 8339cf8f by Sven Tennie at 2026-05-28T17:30:36-04:00 Add Haddock to FileSettings Helping to understand the fields' meanings without deeper analyses. - - - - - 4ce251e4 by Sylvain Henry at 2026-05-28T17:31:39-04:00 foundation test: skip signed minBound `quot` (-1) (#27222) `minBound `quot` (-1)` for fixed-width signed integers is platform dependent: the mathematical result -minBound is not representable in the type. On x86, IDIV traps; LLVM's sdiv is undefined behaviour in this case; on AArch64/RISC-V, SDIV wraps to minBound. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply(a)anthropic.com> - - - - - b8ba7e61 by Simon Jakobi at 2026-05-28T17:32:23-04:00 Prevent dictionary-passing in checkTyEqRhs ...by pre-specializing it to TcM. Previously, wherever checkTyEqRhs was used in other modules, the Core showed dictionary passing ($fMonadIOEnv). The added SPECIALIZE pragma prevents this. - - - - - d603477f by David Eichmann at 2026-05-29T13:17:12-04:00 Hadrian: create a ghc-internal .def file per ghc-internal dll The .def file generated from rts/win32/libHSghc-internal.def.in contains the name of the ghc-internal dll. The correct dll name differs based on if the dll is inplace/final and if using the Dynamic way. Previously, this was not accounted for and inconsistent dlls names where used. That led to failure when loading dlls at runtime in experiments with windows dynamic linking. - - - - - 1fc21753 by Sylvain Henry at 2026-05-29T13:18:14-04:00 ghc-bignum: copy backend interface haddocks to Native backend (#27305) The haddock comments documenting the BigNat backend interface (function contracts, expected MutableWordArray# sizes, return-value semantics, etc.) were attached to the FFI backend module. Copy them to the Native backend so they remain in tree once the FFI backend is removed. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply(a)anthropic.com> - - - - - 717059df by Sylvain Henry at 2026-05-29T13:18:14-04:00 ghc-bignum: remove FFI backend (#27305) The FFI backend of ghc-bignum (now part of ghc-internal) had no known users and is easy to recreate by relinking ghc-internal with a custom backend. Remove the backend module, the bignum-ffi cabal flag, and the ffi option from Hadrian's --bignum selector. The backend interface documentation now lives in the Native backend module. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply(a)anthropic.com> - - - - - 4bb3b1d8 by Sylvain Henry at 2026-05-29T13:18:14-04:00 ghc-bignum: remove Check backend (#27305) The Check backend of ghc-bignum (now part of ghc-internal) compared the selected backend's output against the Native backend for validation. It had no known users. Remove the backend module, the bignum-check cabal flag, the bignumCheck Hadrian flavour field, and the check- prefix in Hadrian's --bignum selector. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply(a)anthropic.com> - - - - - 6b3044a0 by David Eichmann at 2026-05-30T11:58:48-04:00 Add code comments to allocator code - - - - - f4e04210 by Matthew Pickering at 2026-05-30T11:59:34-04:00 hadrian: Refactor system-cxx-std-lib rules I noticed a few things wrong with the hadrian rules for `system-cxx-std-lib` rules. * For `text` there is an ad-hoc check to depend on `system-cxx-std-lib` outside of `configurePackage`. * The `system-cxx-std-lib` dependency is not read from cabal files. * Recache is not called on the packge database after the `.conf` file is generated, a more natural place for this rule is `registerRules`. Treating this uniformly like other packages is complicated by it not having any source code or a cabal file. However we can do a bit better by reporting the dependency firstly in `PackageData` and then needing the `.conf` file in the same place as every other package in `configurePackage`. This commit increases the `shakeVersion`, to provide backwards compatibility to previous builds with different PackageData. Fixes #25303 Co-authored-by: Sven Tennie <sven.tennie(a)gmail.com> - - - - - 576987d0 by Simon Jakobi at 2026-06-02T04:53:36-04:00 compiler: use nubOrd from containers Address #27103 by replacing GHC.Utils.Misc.ordNub[On] with Data.Containers.ListUtils.nubOrd[On]. Note that nubOrd suffers from a small inefficiency, a fix for which will be included in the next containers release: https://github.com/haskell/containers/issues/1202 - - - - - deea53c3 by David Eichmann at 2026-06-02T04:54:22-04:00 Hadrian: disable response files for GHC/Haddock builders on non-Windows This makes debugging build errors easier on non-windows hosts. See issue #27230 - - - - - f2f5c6ba by Nikita Efremov at 2026-06-02T16:04:54+00:00 fix typo : compete with performance, not complete - - - - - 5524ea0e by Wolfgang Jeltsch at 2026-06-03T08:01:26-04:00 Make the current `base` buildable with GHC 9.14 This comprises the following changes: * Disable some imports into `GHC.Base` for GHC 9.14 * Disable some imports into `Prelude` for GHC 9.14 * Disable separate `ArrowLoop` import for GHC 9.14 * Disable `GHC.Internal.STM` import for GHC 9.14 * Disable `GHC.Internal.Unicode.Version` import for GHC 9.14 * Disable `GHC.Internal.TH.Monad` import for GHC 9.14 * Add alternative `fixIO` import for GHC 9.14 * Add alternative `unsafeCodeCoerce` import for GHC 9.14 * Disable hiding of imported SIMD operations for GHC 9.14 * Disable use of GHC 9.14’s `printToHandleFinalizerExceptionHandler` * Enable use of `getFileHash` from `ghc-internal` for GHC 9.14 * Make `thenA` available for GHC 9.14 * Make `thenM` available for GHC 9.14 * Disable translation of `IoManagerFlagPoll` for GHC 9.14 * Add `hGetNewlineMode` for GHC 9.14 - - - - - d3438055 by Enrico Maria De Angelis at 2026-06-03T08:02:17-04:00 Fix #27067 - Clarify haddocks on `minusNaturalMaybe` - - - - - f9bcfac2 by sheaf at 2026-06-03T14:47:19-04:00 Avoid mkTick in Core Prep breaking ANF As discovered in #27182, mkTick can break ANF. This patch introduces a variant of mkTick that skips the single optimisation that could break ANF. This is preferrable over switching to the raw Tick constructor, as the latter may introduce spurious cost centres in profiling reports. This is a temporary measure until we more thoroughly refactor how mkTick works (see #27141). See Note [mkTick breaks ANF] in GHC.CoreToStg.Prep. Fixes #27182 - - - - - cf1fd661 by Artem Pelenitsyn at 2026-06-03T14:48:09-04:00 clarify comment for getSizeofMutableByteArray#: we get the size in bytes, not "elements" - - - - - a3b431f3 by David Eichmann at 2026-06-04T10:10:19+00:00 Hadrian: convert env variable ACLOCAL_PATH to unix paths. Convert ACLOCAL_PATH to a unix style path when invoking autoreconf. Autoreconf doesn't handle windows paths. See Note [Autoreconf unix paths from ACLOCAL_PATH]. Fixes #27311 - - - - - 18f6138a by Simon Jakobi at 2026-06-04T20:20:31-04:00 testsuite: Deduplicate --only test names config.only is assumed to be a set, but supplying --only overwrote it with the (list) argparse result, which can contain duplicates. When a test ran, config.only.remove(name) dropped only the first occurrence, so a duplicated name lingered and was later misreported as a "test not found" framework failure. Store it as a set instead. Fixes #27322 Co-Authored-By: Claude Opus 4.7 <noreply(a)anthropic.com> - - - - - 2f3cc9ff by Simon Jakobi at 2026-06-08T07:55:49-04:00 testsuite: detect fast bignum via ghc-internal, not removed ghc-bignum The ghc-bignum package was merged into ghc-internal, so the BIGNUM_GMP probe in test.mk ran `ghc-pkg field ghc-bignum exposed-modules`, which fails with "cannot find package ghc-bignum". That error went to stderr and leaked into the captured stderr of every makefile_test, causing spurious [bad stderr] failures across the suite. The probe also silently returned empty, so config.have_fast_bignum was wrongly False even on GMP builds. Probe ghc-internal's extra-libraries for the gmp library instead: the GMP backend module is an other-module (not exposed), but GMP_LIBS adds gmp to extra-libraries only on a GMP build, so this distinguishes the backends. Redirect stderr to keep any future missing-package error off the harness's stderr. This also removes a stale comment as per suggestion from hsyl20. Co-Authored-By: Claude Opus 4.7 <noreply(a)anthropic.com> - - - - - eb3bf6e7 by Alan Zimmerman at 2026-06-08T07:56:32-04:00 EPA: Rename Transform.anchorEof to addModuleCommentOrigDeltas This now matches what it actually does. - - - - - 498bb21a by David Eichmann at 2026-06-09T18:02:39-04:00 Hadrian: avoid response files when command line is short enough This replaces the logic of always using response files on Windows. With the new condition based on command line lenght, reponse files can be avoided in many more cases (on windows). Now that response files are only used in a small number of cases, response files are always kept and the -r / --keep-response-files command line options have been removed The response file paths are nolonger randomized. They are placed in the `_build/rsp` directory. This ensures they are ignored by git and we that Hadrian reuses response file paths when rebuilding rather than leaving stale response files around. Update user guide putting response files in its own section - - - - - 87f510a5 by Simon Hengel at 2026-06-09T18:03:25-04:00 Don't use non-breaking spaces - - - - - 41a19379 by David Eichmann at 2026-06-09T18:04:11-04:00 Hadrian: remove unused wrapper scripts from windows bindist These wrapper scripts are only installed on non-relocatable builds which are not generally supported on windows. - - - - - ce01ccb6 by sheaf at 2026-06-10T05:08:48-04:00 Don't drop ticks around variables of type `IO ()` GHC.Core.Utils.mkTick is responsible for placing a tick on a Core expression. It contains logic for dropping SCCs (non-counting profiling ticks) around non-function variables, as such variables cannot meaningfully contribute to profiles. However, the logic for what counts as a function was incorrect: it used `isFunTy` which returns 'False' for types such as 'IO ()' where the function arrow is hidden under a newtype. We now use 'mightBeFunTy' instead of 'isFunTy'. This ensures we don't drop ticks in cases we aren't sure. On the way, we improve the documentation of 'isFunTy', 'isPiTy' and 'mightBeFunTy', and update the latter's implementation to consistently handle unary classes. Fixes #27225 ------------------------- Metric Decrease: T5642 ------------------------- - - - - - d311c4f1 by Simon Jakobi at 2026-06-10T05:09:32-04:00 testsuite: Add regression test for #4081 Check that a strict constructor field is unboxed once outside an enclosing loop, not re-inspected each iteration (the float-out case-floating from 9cb20b488). Uses simonpj's `data T a = T !a` example from the ticket; T4081.stderr captures the expected Core. Co-Authored-By: Claude Opus 4.7 <noreply(a)anthropic.com> - - - - - 333df444 by sheaf at 2026-06-10T05:10:25-04:00 Check for cabal-install >= 3.12 upfront Starting with commit 8cb99552f607f6bc4000e45ab32532d50c8bb996, Hadrian requires cabal-install >= 3.12 in order to use the 'cabal path' command that was introduced in version 3.12, as per https://github.com/haskell/cabal/blob/a51c4ee1556d816ad86e90db7e6330dd51b0b… This was not reflected in the Hadrian build script, causing a delayed build failure instead of enforcing the version requirement upfront, which this patch does. Fixes #27317 - - - - - 98c20394 by sheaf at 2026-06-10T05:11:09-04:00 Fix crash in Data.Data instance for HsCtxt The Data.Data instance for HsCtxt contained an error for the 'toConstr' method, which could trigger for example when looking at -ddump-tc-ast traces. Replace it with the 'abstractConstr' pattern used in the rest of the codebase. - - - - - 5ac9ce7d by Zubin Duggal at 2026-06-10T21:26:32+05:30 hadrian: Remove old package.conf files when generating new ones Old package.conf files might exists with different hashes, causing issues like #26661 Fixes #26661 - - - - - c9015f09 by sheaf at 2026-06-11T12:40:28-04:00 Fix AArch64 clobbering bug for MUL2 On AArch64, the code generator could clobber one of the input operands when computing the lower bits of a MUL2 operation. This rendered invalid the subsequent computation of the high bits. This commit fixes that by using a temporary register. The register allocator can remove the redundant move in the common case when the registers do not conflict. Fixes #27046 - - - - - 7ab90288 by Rodrigo Mesquita at 2026-06-11T12:41:11-04:00 fix: make T27131 less flaky It seems that T27131 fails flakily in a race where we check the flag before the capability had the chance to process the mailbox which sets the flag. This seemingly should only happen if the capability ends up being the same for setting and checking the flag. - - - - - 8965cb76 by Marc Scholten at 2026-06-12T04:53:22-04:00 haddock: render modules concurrently - - - - - 8cc0b64a by Duncan Coutts at 2026-06-12T04:54:06-04:00 Promote HAVE_PREEMPTION from Timer.c to OSThreads.h We will want to know about HAVE_PREEMPTION in more places. HAVE_PREEMPTION tells us that we do have OS threads available, irrespective of whether THREADED is defined. In particular, HAVE_PREEMPTION is defined on all proper OSs, but not on WASM (and hyopthetically may not be true on some other platforms like micro-controllers, RTOSs, VM hypervisors etc). - - - - - cce574ed by Duncan Coutts at 2026-06-12T04:54:06-04:00 Define ACQUIRE_LOCK_ALWAYS and friends Fix issue #27335 Like the atomic _ALWAYS variants, these lock actions are always defined, rather than being dependent on whether we are in the THREADED case. All the "normal" LOCK macros are defined to be no-ops when !THREADED. The use case for the _ALWAYS variants is where we are using OS threads even in the non-threaded RTS. This includes everything to do with the timer/ticker thread, which is used in the non-threaded RTS too. In particular, we will want to use this for eventlog things, because the timer thread performs eventlogging concurrently with the main capability, even in the non-threaded RTS. - - - - - 1f28d1f6 by Duncan Coutts at 2026-06-12T04:54:06-04:00 Use ACQUIRE/RELEASE_LOCK_ALWAYS with eventBufMutex Even in the non-threaded RTS the eventBufMutex is needed by both the main capability and the timer/ticker thread, so always use the mutex. This should fix #25165 which is about the main capability and the timer thread posting events to the eventlog buffer concurrently and thereby corrupting the buffer data. - - - - - 0ff29782 by Duncan Coutts at 2026-06-12T04:54:06-04:00 Expose eventBufMutex in the EventLog interface/header We will need it in forkProcess to ensure we don't write to the global eventlog buffer concurrently with trying to flush eventlog buffers and do the fork(). - - - - - 7a688395 by Duncan Coutts at 2026-06-12T04:54:07-04:00 Split flushAllCapsEventsBufs into safe and unlocked version Following the convention that unlocked versions have a trailing _ underscore in their name. This one requires the caller to hold the eventlog global buffer mutex. We will need this in forkProcess. - - - - - 341ed474 by Duncan Coutts at 2026-06-12T04:54:07-04:00 Remove redundant use of stopTimer in setNumCapabilities Historically, the comment here was: We must stop the interval timer while we are changing the capabilities array lest handle_tick may try to context switch an old capability. See #17289. and We must disable the timer while we do this since the tick handler may call contextSwitchAllCapabilities, which may see the capabilities array as we free it. What this refers to is that historically, when changing the number of capabilities, the array of capabilities was reallocated to a new size, allocating new ones and freeing the old ones, thus invalidating all existing capbility pointers. Strangely, for good measure the code used to call stopTimer twice (hence the two similar comments above). However, since commit a3eccf06292dd666b24606251a52da2b466a9612, the capabilities array is no longer reallocated. Instead the array is allcoated once on RTS startup to the maximum size it could ever be allowed to be, and then capabilities get enabled/disabled at runtime. So the capability pointers never become invalid anymore. At worst, they may point to capabilities that are disabled. Thus we no longer need to stop the timer (twice) while we change the number of enabled capabilities. This also partially solves issue #27105, which notes that stopTimer is being used as if it were synchronous, when it is not. At least for this case, the solution is that stopTimer is not needed at all! - - - - - 674858e3 by Duncan Coutts at 2026-06-12T04:54:07-04:00 Remove redundant use of stopTimer in forkProcess but replace it with taking the eventlog buffer lock during the fork. Fixes issue #27105 The original reason to block the timer during a fork was that historically the timer was implemented using a periodic timer signal, and the signal itself would interrupt the fork system call (returning EINTR). For large processes (where fork() takes a while) this could permanently livelock: the timer always would go off before the fork could complete, which got retried in a loop forever. The timer is no longer implemented as a unix signal, but uses threads. Thus the original problem no longer exists. The only remaining reason to block the timer tick is to prevent actions taken by the tick from interfering with the delicate process involved in fork (taking a load of locks and pausing everything). The only thing we need to do is to prevent the eventlog from being written to or flushed while the fork is taking place. To achieve this all we need to do is hold the mutex for the global eventlog buffer. This removes the last use of stopTimer that expects stopTimer to work synchronously (which it was not) and thus solves issue #27105. To be clear, we solve issue #27105 not by making stopTimer synchronous, but by eliminating the use sites that expected it to be synchronous. - - - - - 40764930 by sheaf at 2026-06-12T14:54:43-04:00 Add type family performance test for #26426 Some GHC versions produced large numbers of coercions after typechecking and desugaring when compiling the program in #26426: Version | Typechecker time | Typechecker allocations | Coercions -------:|-----------------:|------------------------:|---------: 9.6 | 47 ms | 48 MB | 110k 9.8 | 1000 ms | 486 MB | 10,437k 9.10 | 922 ms | 489 MB | 10,436k 9.12 | 906 ms | 482 MB | 10,437k 9.14 | 63 ms | 55 MB | 333k 10.0 | 47 ms | 64 MB | 35k The improvement 9.12 -> 9.14 was due to commit 22d11fa818fae2c95c494fc0fac1f8cb4c6e7cb6, while the improvement 9.14 -> 10.0 was due to commit 0b7df6db9e46df40e86fbff1a66dc10440b99db5. As the behaviour of GHC seems better than it's ever been on this program, we declare victory, adding this performance test to ensure we don't regress on this program. On the way, we update Note [Combining equalities] in GHC.Tc.SolveR.Equality with the explanation of the 9.12 -> 9.14 improvement (getting rid of an exponential blowup in coercion sizes), and we update Note [Exploiting closed type families] in GHC.Tc.Solver.FunDeps with the explanation of the 9.14 -> 10.0 improvement (bringing down coercion size growth from cubic to quadratic). - - - - - 0f3d0a71 by Zubin Duggal at 2026-06-12T14:55:30-04:00 compiler: mark tool messages as errors/warnings depending on the exit code Fixes #27370 - - - - - d9ea2d76 by mangoiv at 2026-06-13T04:41:51-04:00 libraries/process: bump submodule to v1.6.30.0 - bump the submodule to the appropriate tag - suppress benign warning resulting from the change - - - - - 6ebaaba3 by David Eichmann at 2026-06-13T04:42:37-04:00 ghc-toolchain: don't throw when candidate executables are not found Fixes #27369 - - - - - 6c65e1e1 by David Eichmann at 2026-06-13T04:43:23-04:00 CI: lint-changelog checks for no-changelog label in script instead of rules - - - - - bab37cc6 by konsumlamm at 2026-06-13T19:10:21+02:00 Implement CLC proposal #378 Add `Data.Double` and `Data.Float` modules Document that GHC uses IEEE 754 - - - - - fb5246ad by fendor at 2026-06-15T18:07:23-04:00 Drop `preloadClosure` from `UnitState` It is always hard-coded to the same value. Backpack Unit instantiation isn't using it any more. Allows us to simplify the API and get rid of `improveUnit`. - - - - - 291ce3aa by ARATA Mizuki at 2026-06-15T18:08:26-04:00 RISC-V NCG: Zero-extend the result of castFloatToWord32 According to the ISA manual, FMV.X.W sign-extends the result. We need to truncate the result to avoid creating an exotic Word32 value. Fixes #27300 - - - - - 011be91f by ARATA Mizuki at 2026-06-15T18:08:26-04:00 RISC-V NCG: Treat d28-d31 (ft8-ft11) as caller-saved According to the calling convention, the registers d28-d31 (ft8-ft11) are caller-saved. Fixes #27306 - - - - - e8a54713 by ARATA Mizuki at 2026-06-15T18:08:26-04:00 RISC-V NCG: Set rounding mode when emitting `truncate` If we omit the rounding mode for `fcvt`, `dyn` will be used. We do not want that for `truncate`, so we set `rtz`. In other places, we set `rne` because we do not use the dynamic rounding mode. Fixes #27303 - - - - - 9438bec7 by Zubin Duggal at 2026-06-15T18:09:11-04:00 rts: fix validate build with gcc 16. `__attribute__((regparm(1)))` is ignored on x86_64 and now gcc warns that it is ignored: rts/sm/Evac.h:35:1: error: error: ‘regparm’ attribute ignored [-Werror=attributes] See https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=ccead81bbc39668376eb5cf47066a… Fixes #27366 - - - - - 893e6133 by Andrew Lelechenko at 2026-06-15T23:55:36+01:00 base: more NonEmpty zips CLC proposal: https://github.com/haskell/core-libraries-committee/issues/409 - - - - - 1314f2fd by David Eichmann at 2026-06-16T05:46:52-04:00 Hadrian: fix ghc-internal .def file name - - - - - 7f72bcb3 by mangoiv at 2026-06-16T05:47:39-04:00 compiler: ignore camelCase and Eta reduce hlint hints These do not cohere with the style used in GHC. After disabling them, hlint lints are much less noisy again. - - - - - 842bef9f by Alan Zimmerman at 2026-06-16T05:48:25-04:00 EPA: Use standard type family declaration for Anno - - - - - f6d30767 by Wolfgang Jeltsch at 2026-06-16T15:32:34-04:00 Fix two issues in the documentation of pipeline interruption One issue is a typo (“interreuptible”), the other one the lack of an end of a sentence, which has been reconstructed from the message of 633bbc1fd4762a2bb73ba1c5b9e0c279f1dd3c40, the commit that introduced said documentation. - - - - - a3fa10e0 by Christian Georgii at 2026-06-16T15:33:26-04:00 Find plugins in sibling home units in multiple-home-unit sessions In a multiple-home-unit session (e.g. `cabal repl --enable-multi-repl` or HLS), enabling a plugin with -fplugin that is defined in (or reexported by) another home unit failed with a "hidden package" error. The plugin module finder only searched the current home unit and the registered external packages, never the sibling home units. findPluginModuleNoHsc now searches the home units that the current home unit depends on, following module reexports and respecting hidden modules, exactly as ordinary import resolution does in findImportedModuleNoHsc. To avoid two divergent copies of this logic, the shared home-unit search (the current home unit first, then its dependencies in priority order, with the accompanying ordering invariant) is extracted into findHomeModuleAmongDeps, which both findImportedModuleNoHsc and findPluginModuleNoHsc now call. Add testsuite/tests/driver/multipleHomeUnits/plugin01, which loads a plugin as byte-code from a sibling home unit, and plugin02, in which the consumer enables a plugin reexported by a sibling home unit without depending on the plugin's own home unit directly. Fixes #27349 - - - - - d216412b by Ian-Woo Kim at 2026-06-16T20:25:57-04:00 Make the order of usages deterministic It has been observed that the ordering of usages can be non-determinstic in parallel builds. Therefore, this contribution introduces sorting of usages based on a platform- and race-independent sorting criterion. Resolves #26877. Co-authored-by: Wolfgang Jeltsch <wolfgang(a)well-typed.com> - - - - - 8e1cc105 by Wolfgang Jeltsch at 2026-06-16T20:25:57-04:00 Change the descriptions of two existing changelog entries The descriptions now describe the changes in a user-friendly manner, as opposed to describing the contributions that led to these changes in a developer-friendly manner. - - - - - 636c1c7a by Ian Duncan at 2026-06-16T20:26:50-04:00 AArch64: use SXTH, not SXTW, for W32 signExtendReg signExtendReg was using SXTH (sign-extend halfword, 16-bit) for W32-to-W64 sign extension. This should be SXTW (sign-extend word, 32-bit). SXTH only sign-extends the lower 16 bits, producing wrong results for 32-bit values whose bit 15 differs from bit 31. Other fixes: - At sub-W64, code gen for MO_S_Mul2 should use W32 registers for SMULL source operands as per the ARM spec (SMULL Xd, Wn, Wm), and not W64. - Ensure signExtendReg uses the source width for the source operand in SXTW/SXTH/SXTB instructions. GNU as requires sxtw Xd,Wn (not sxtw Xd,Xn), while LLVM's integrated assembler on macOS is lenient. - Fix overflow flag computation for `MO_S_Mul2`. The overflow bit was exactly inverted for sub-W64 operands. Fixes #26978 and #27047 - - - - - b734c75d by Igor Ranieri at 2026-06-16T20:27:32-04:00 haddock: Update CONTRIBUTING with missing step, add missing test dependency - - - - - 7fe4f2ec by Luite Stegeman at 2026-06-17T05:35:09-04:00 tag inference: don't confuse functions with their return values inferTagRhs was mixing up taggedness for closures and return values for function closures. We really shouldn't assign TagTuple to a properly tagged function returning a tuple. We fix this by keeping track of functions (TagFun) separately from values (TagVal) and keeping track of their return value. TagFun is also used for join points. fixes #27005 - - - - - 4671c126 by Sebastian Graf at 2026-06-17T05:35:55-04:00 Seed the simplifier's in-scope set for open expressions simplifyExpr simplifies expressions typed at the GHCi prompt and the results of Template Haskell splices. Such an expression may be open: at a GHCi debugger breakpoint its free variables include RuntimeUnk skolems standing for as-yet-unknown types. The simplifier began with an in-scope set holding only the wildcard binder, so when it instantiated the unsafeCoerce# wrapper that GHCi builds around a result, it formed a substitution whose range mentioned a free skolem that was not in scope. That breaks the substitution invariant and, in a compiler built with assertions, trips substTy's sanity check. Seed the initial in-scope set with the free variables of the expression. For a closed expression this adds nothing. See Note [Seed the in-scope set for open expressions]. Fixes #17833 and its duplicate #21118. - - - - - 67d41299 by Sebastian Graf at 2026-06-18T05:18:24-04:00 Desugar a `case` scrutinee only once (#27383, #20251) In `dsExpr` for `HsCase` we desugared the scrutinee /twice/: once to build the Core `case` itself, and again inside `matchWrapper`, which re-desugared the source scrutinee (via `addHsScrutTmCs`) purely to record long-distance information for the pattern-match checker. For a single `case` that is merely wasteful. But for nested cases it is catastrophic. Consider case (case (case e of ... ) of ... ) of ... Desugaring the outer scrutinee desugars the middle `case` twice, each of which desugars the inner `case` twice, and so on. The work doubles at every level, so desugaring takes O(2^n) time in the nesting depth. That is the blowup reported in #27383; it is also what makes the machine-generated program in #20251 take an age to compile. The fix is simple. `matchWrapper` is handed the scrutinee anyway, so we give it the Core expression we have /already/ desugared, and record the long-distance term constraint with `addCoreScrutTmCs` instead of re-desugaring from source. This is just what `matchSinglePatVar` already does for single-pattern matches. So: * `matchWrapper` now takes `Maybe [CoreExpr]` rather than `Maybe [LHsExpr GhcTc]`. * The `HsCase` equation of `dsExpr` passes the already-desugared `core_discrim`; the arrow desugarer passes its match variables. * `addHsScrutTmCs` had no other use, so it is gone. Desugaring is now linear in the nesting depth. (The coverage checker still runs `simpleOptExpr` over each scrutinee, which leaves the total at O(n^2); that is ample.) The long-distance information itself is unchanged: the checker sees precisely the Core that backs the generated code. Test: deSugar/should_compile/T27383 - - - - - fa5defde by Rodrigo Mesquita at 2026-06-18T05:19:11-04:00 fix: Save FastStrings in the PMC There is no point in adding the unique to the occurrence FastString we create, since it is part of the Id anyway. Adding it to the FastString, meant each FastString was unique unnecessarily! In a separate branch, running the compiler on test `InstanceMatching` observed 30000 `FastString`s created by this code path. Plus, `fsLit "pm"` follows the existing pattern in `mkPmId`. - - - - - 4efb4a66 by Alan Zimmerman at 2026-06-18T14:41:14-04:00 TTG: Add extension points to HsConDetails Extend HsConDetails as data HsConDetails p arg rec = PrefixCon !(XPrefixCon p) [arg] -- C @t1 @t2 p1 p2 p3 | RecCon !(XRecCon p) rec -- C { x = p1, y = p2 } | InfixCon !(XInfixCon p) arg arg -- p1 `C` p2 | XHsConDetails !(XXHsConDetails p) type family XPrefixCon p type family XRecCon p type family XInfixCon p type family XXHsConDetails p - - - - - c8d27dd4 by Simon Jakobi at 2026-06-18T14:41:59-04:00 CI: quiet submodule clean output in after_script and setup The clean and cleanup_submodules functions ran 'git submodule foreach git clean -xdf', flooding the job log with 'Entering ...' and 'Removing ...' lines. Pass --quiet to 'git submodule' and -q to 'git clean' to drop the success output; errors are still reported. Co-Authored-By: Claude Opus 4.8 <noreply(a)anthropic.com> - - - - - 6009c460 by Simon Hengel at 2026-06-22T04:21:10+07:00 Don't use global variables to address concurrency bugs! (fixes #27234) This was originally introduce with 88f38b03025386f0f1e8f5861eed67d80495168a to address #17922. In this specific case a better fix would have been to synchronize on stderr: withHandle_ "stderrSupportsAnsiColors" stderr $ \ _ -> do ... But apparently the dependency on `terminfo` was removed in 32ab07bf3d6ce45e8ea5b55e8095174a6b42a7f0, preventing #17922 in the first place. - - - - - 562 changed files: - .gitlab-ci.yml - .gitlab/ci.sh - .gitmodules - boot - + changelog.d/T17833 - + changelog.d/T26978 - + changelog.d/T26979 - + changelog.d/T27046 - + changelog.d/T27047 - + changelog.d/T27182.md - + changelog.d/T27202 - + changelog.d/T27225 - + changelog.d/T27261 - + changelog.d/T27308 - + changelog.d/T27317 - + changelog.d/T27359 - + changelog.d/bump-process - + changelog.d/deterministic-usage-order - changelog.d/dynamic-trace-flags - + changelog.d/elem-via-foldr-27096 - + changelog.d/fix-blackhole-handling - + changelog.d/fix-exponential-case-desugar-27383 - + changelog.d/fix-plugin-finder-multi-home-unit.md - + changelog.d/ghc-pkg-faster-closure - changelog.d/hadrian-response-files.md - + changelog.d/hadrian-stale-package-confs-26661 - + changelog.d/hadrian-system-cxx-std-lib-25303 - + changelog.d/ipe-event-class - + changelog.d/jobserver-leak-fix - 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testsuite/tests/ghc-api/fixed-nodes/InterfaceModuleGraph.hs - + testsuite/tests/ghc-api/settings/LibDir.hs - + testsuite/tests/ghc-api/settings/LibDir.stdout - + testsuite/tests/ghc-api/settings/all.T - testsuite/tests/ghci.debugger/scripts/all.T - + testsuite/tests/ghci/prog-mhu006/Makefile - + testsuite/tests/ghci/prog-mhu006/a/A.hs - + testsuite/tests/ghci/prog-mhu006/all.T - + testsuite/tests/ghci/prog-mhu006/b/B.hs - + testsuite/tests/ghci/prog-mhu006/prog-mhu006a.script - + testsuite/tests/ghci/prog-mhu006/prog-mhu006a.stdout - + testsuite/tests/ghci/prog-mhu006/unitA - + testsuite/tests/ghci/prog-mhu006/unitB - testsuite/tests/ghci/prog003/prog003.script - testsuite/tests/ghci/prog018/prog018.stdout - testsuite/tests/ghci/prog020/Makefile - testsuite/tests/ghci/prog020/all.T - testsuite/tests/ghci/prog020/ghci.prog020.script → testsuite/tests/ghci/prog020/ghci.prog020a.script - testsuite/tests/ghci/prog020/ghci.prog020.stderr → testsuite/tests/ghci/prog020/ghci.prog020a.stderr - testsuite/tests/ghci/prog020/ghci.prog020.stdout → testsuite/tests/ghci/prog020/ghci.prog020a.stdout - + testsuite/tests/ghci/prog020/ghci.prog020b.script - + testsuite/tests/ghci/prog020/ghci.prog020b.stderr - + testsuite/tests/ghci/prog020/ghci.prog020b.stdout - + testsuite/tests/ghci/prog023/Makefile - + testsuite/tests/ghci/prog023/all.T - + testsuite/tests/ghci/prog023/prog023a.script - + testsuite/tests/ghci/prog023/prog023a.stdout - + testsuite/tests/ghci/prog023/prog023b.script - + testsuite/tests/ghci/prog023/prog023b.stdout - + testsuite/tests/ghci/prog023/src/A.hs - + testsuite/tests/ghci/prog024/Makefile - + testsuite/tests/ghci/prog024/all.T - + testsuite/tests/ghci/prog024/prog024a.script - + testsuite/tests/ghci/prog024/prog024a.stdout - + testsuite/tests/ghci/prog024/prog024b.script - + testsuite/tests/ghci/prog024/prog024b.stdout - + testsuite/tests/ghci/prog024/prog024c.script - + testsuite/tests/ghci/prog024/prog024c.stderr - + testsuite/tests/ghci/prog024/prog024c.stdout - 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View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/dea6fdbf72c920be81448029dfcf84… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/dea6fdbf72c920be81448029dfcf84… You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][wip/sol/haddock-list-indices-bug] 48 commits: testsuite: detect fast bignum via ghc-internal, not removed ghc-bignum
by Simon Hengel (＠sol) 22 Jun '26

22 Jun '26

Simon Hengel pushed to branch wip/sol/haddock-list-indices-bug at Glasgow Haskell Compiler / GHC Commits: 2f3cc9ff by Simon Jakobi at 2026-06-08T07:55:49-04:00 testsuite: detect fast bignum via ghc-internal, not removed ghc-bignum The ghc-bignum package was merged into ghc-internal, so the BIGNUM_GMP probe in test.mk ran `ghc-pkg field ghc-bignum exposed-modules`, which fails with "cannot find package ghc-bignum". That error went to stderr and leaked into the captured stderr of every makefile_test, causing spurious [bad stderr] failures across the suite. The probe also silently returned empty, so config.have_fast_bignum was wrongly False even on GMP builds. Probe ghc-internal's extra-libraries for the gmp library instead: the GMP backend module is an other-module (not exposed), but GMP_LIBS adds gmp to extra-libraries only on a GMP build, so this distinguishes the backends. Redirect stderr to keep any future missing-package error off the harness's stderr. This also removes a stale comment as per suggestion from hsyl20. Co-Authored-By: Claude Opus 4.7 <noreply(a)anthropic.com> - - - - - eb3bf6e7 by Alan Zimmerman at 2026-06-08T07:56:32-04:00 EPA: Rename Transform.anchorEof to addModuleCommentOrigDeltas This now matches what it actually does. - - - - - 498bb21a by David Eichmann at 2026-06-09T18:02:39-04:00 Hadrian: avoid response files when command line is short enough This replaces the logic of always using response files on Windows. With the new condition based on command line lenght, reponse files can be avoided in many more cases (on windows). Now that response files are only used in a small number of cases, response files are always kept and the -r / --keep-response-files command line options have been removed The response file paths are nolonger randomized. They are placed in the `_build/rsp` directory. This ensures they are ignored by git and we that Hadrian reuses response file paths when rebuilding rather than leaving stale response files around. Update user guide putting response files in its own section - - - - - 87f510a5 by Simon Hengel at 2026-06-09T18:03:25-04:00 Don't use non-breaking spaces - - - - - 41a19379 by David Eichmann at 2026-06-09T18:04:11-04:00 Hadrian: remove unused wrapper scripts from windows bindist These wrapper scripts are only installed on non-relocatable builds which are not generally supported on windows. - - - - - ce01ccb6 by sheaf at 2026-06-10T05:08:48-04:00 Don't drop ticks around variables of type `IO ()` GHC.Core.Utils.mkTick is responsible for placing a tick on a Core expression. It contains logic for dropping SCCs (non-counting profiling ticks) around non-function variables, as such variables cannot meaningfully contribute to profiles. However, the logic for what counts as a function was incorrect: it used `isFunTy` which returns 'False' for types such as 'IO ()' where the function arrow is hidden under a newtype. We now use 'mightBeFunTy' instead of 'isFunTy'. This ensures we don't drop ticks in cases we aren't sure. On the way, we improve the documentation of 'isFunTy', 'isPiTy' and 'mightBeFunTy', and update the latter's implementation to consistently handle unary classes. Fixes #27225 ------------------------- Metric Decrease: T5642 ------------------------- - - - - - d311c4f1 by Simon Jakobi at 2026-06-10T05:09:32-04:00 testsuite: Add regression test for #4081 Check that a strict constructor field is unboxed once outside an enclosing loop, not re-inspected each iteration (the float-out case-floating from 9cb20b488). Uses simonpj's `data T a = T !a` example from the ticket; T4081.stderr captures the expected Core. Co-Authored-By: Claude Opus 4.7 <noreply(a)anthropic.com> - - - - - 333df444 by sheaf at 2026-06-10T05:10:25-04:00 Check for cabal-install >= 3.12 upfront Starting with commit 8cb99552f607f6bc4000e45ab32532d50c8bb996, Hadrian requires cabal-install >= 3.12 in order to use the 'cabal path' command that was introduced in version 3.12, as per https://github.com/haskell/cabal/blob/a51c4ee1556d816ad86e90db7e6330dd51b0b… This was not reflected in the Hadrian build script, causing a delayed build failure instead of enforcing the version requirement upfront, which this patch does. Fixes #27317 - - - - - 98c20394 by sheaf at 2026-06-10T05:11:09-04:00 Fix crash in Data.Data instance for HsCtxt The Data.Data instance for HsCtxt contained an error for the 'toConstr' method, which could trigger for example when looking at -ddump-tc-ast traces. Replace it with the 'abstractConstr' pattern used in the rest of the codebase. - - - - - 5ac9ce7d by Zubin Duggal at 2026-06-10T21:26:32+05:30 hadrian: Remove old package.conf files when generating new ones Old package.conf files might exists with different hashes, causing issues like #26661 Fixes #26661 - - - - - c9015f09 by sheaf at 2026-06-11T12:40:28-04:00 Fix AArch64 clobbering bug for MUL2 On AArch64, the code generator could clobber one of the input operands when computing the lower bits of a MUL2 operation. This rendered invalid the subsequent computation of the high bits. This commit fixes that by using a temporary register. The register allocator can remove the redundant move in the common case when the registers do not conflict. Fixes #27046 - - - - - 7ab90288 by Rodrigo Mesquita at 2026-06-11T12:41:11-04:00 fix: make T27131 less flaky It seems that T27131 fails flakily in a race where we check the flag before the capability had the chance to process the mailbox which sets the flag. This seemingly should only happen if the capability ends up being the same for setting and checking the flag. - - - - - 8965cb76 by Marc Scholten at 2026-06-12T04:53:22-04:00 haddock: render modules concurrently - - - - - 8cc0b64a by Duncan Coutts at 2026-06-12T04:54:06-04:00 Promote HAVE_PREEMPTION from Timer.c to OSThreads.h We will want to know about HAVE_PREEMPTION in more places. HAVE_PREEMPTION tells us that we do have OS threads available, irrespective of whether THREADED is defined. In particular, HAVE_PREEMPTION is defined on all proper OSs, but not on WASM (and hyopthetically may not be true on some other platforms like micro-controllers, RTOSs, VM hypervisors etc). - - - - - cce574ed by Duncan Coutts at 2026-06-12T04:54:06-04:00 Define ACQUIRE_LOCK_ALWAYS and friends Fix issue #27335 Like the atomic _ALWAYS variants, these lock actions are always defined, rather than being dependent on whether we are in the THREADED case. All the "normal" LOCK macros are defined to be no-ops when !THREADED. The use case for the _ALWAYS variants is where we are using OS threads even in the non-threaded RTS. This includes everything to do with the timer/ticker thread, which is used in the non-threaded RTS too. In particular, we will want to use this for eventlog things, because the timer thread performs eventlogging concurrently with the main capability, even in the non-threaded RTS. - - - - - 1f28d1f6 by Duncan Coutts at 2026-06-12T04:54:06-04:00 Use ACQUIRE/RELEASE_LOCK_ALWAYS with eventBufMutex Even in the non-threaded RTS the eventBufMutex is needed by both the main capability and the timer/ticker thread, so always use the mutex. This should fix #25165 which is about the main capability and the timer thread posting events to the eventlog buffer concurrently and thereby corrupting the buffer data. - - - - - 0ff29782 by Duncan Coutts at 2026-06-12T04:54:06-04:00 Expose eventBufMutex in the EventLog interface/header We will need it in forkProcess to ensure we don't write to the global eventlog buffer concurrently with trying to flush eventlog buffers and do the fork(). - - - - - 7a688395 by Duncan Coutts at 2026-06-12T04:54:07-04:00 Split flushAllCapsEventsBufs into safe and unlocked version Following the convention that unlocked versions have a trailing _ underscore in their name. This one requires the caller to hold the eventlog global buffer mutex. We will need this in forkProcess. - - - - - 341ed474 by Duncan Coutts at 2026-06-12T04:54:07-04:00 Remove redundant use of stopTimer in setNumCapabilities Historically, the comment here was: We must stop the interval timer while we are changing the capabilities array lest handle_tick may try to context switch an old capability. See #17289. and We must disable the timer while we do this since the tick handler may call contextSwitchAllCapabilities, which may see the capabilities array as we free it. What this refers to is that historically, when changing the number of capabilities, the array of capabilities was reallocated to a new size, allocating new ones and freeing the old ones, thus invalidating all existing capbility pointers. Strangely, for good measure the code used to call stopTimer twice (hence the two similar comments above). However, since commit a3eccf06292dd666b24606251a52da2b466a9612, the capabilities array is no longer reallocated. Instead the array is allcoated once on RTS startup to the maximum size it could ever be allowed to be, and then capabilities get enabled/disabled at runtime. So the capability pointers never become invalid anymore. At worst, they may point to capabilities that are disabled. Thus we no longer need to stop the timer (twice) while we change the number of enabled capabilities. This also partially solves issue #27105, which notes that stopTimer is being used as if it were synchronous, when it is not. At least for this case, the solution is that stopTimer is not needed at all! - - - - - 674858e3 by Duncan Coutts at 2026-06-12T04:54:07-04:00 Remove redundant use of stopTimer in forkProcess but replace it with taking the eventlog buffer lock during the fork. Fixes issue #27105 The original reason to block the timer during a fork was that historically the timer was implemented using a periodic timer signal, and the signal itself would interrupt the fork system call (returning EINTR). For large processes (where fork() takes a while) this could permanently livelock: the timer always would go off before the fork could complete, which got retried in a loop forever. The timer is no longer implemented as a unix signal, but uses threads. Thus the original problem no longer exists. The only remaining reason to block the timer tick is to prevent actions taken by the tick from interfering with the delicate process involved in fork (taking a load of locks and pausing everything). The only thing we need to do is to prevent the eventlog from being written to or flushed while the fork is taking place. To achieve this all we need to do is hold the mutex for the global eventlog buffer. This removes the last use of stopTimer that expects stopTimer to work synchronously (which it was not) and thus solves issue #27105. To be clear, we solve issue #27105 not by making stopTimer synchronous, but by eliminating the use sites that expected it to be synchronous. - - - - - 40764930 by sheaf at 2026-06-12T14:54:43-04:00 Add type family performance test for #26426 Some GHC versions produced large numbers of coercions after typechecking and desugaring when compiling the program in #26426: Version | Typechecker time | Typechecker allocations | Coercions -------:|-----------------:|------------------------:|---------: 9.6 | 47 ms | 48 MB | 110k 9.8 | 1000 ms | 486 MB | 10,437k 9.10 | 922 ms | 489 MB | 10,436k 9.12 | 906 ms | 482 MB | 10,437k 9.14 | 63 ms | 55 MB | 333k 10.0 | 47 ms | 64 MB | 35k The improvement 9.12 -> 9.14 was due to commit 22d11fa818fae2c95c494fc0fac1f8cb4c6e7cb6, while the improvement 9.14 -> 10.0 was due to commit 0b7df6db9e46df40e86fbff1a66dc10440b99db5. As the behaviour of GHC seems better than it's ever been on this program, we declare victory, adding this performance test to ensure we don't regress on this program. On the way, we update Note [Combining equalities] in GHC.Tc.SolveR.Equality with the explanation of the 9.12 -> 9.14 improvement (getting rid of an exponential blowup in coercion sizes), and we update Note [Exploiting closed type families] in GHC.Tc.Solver.FunDeps with the explanation of the 9.14 -> 10.0 improvement (bringing down coercion size growth from cubic to quadratic). - - - - - 0f3d0a71 by Zubin Duggal at 2026-06-12T14:55:30-04:00 compiler: mark tool messages as errors/warnings depending on the exit code Fixes #27370 - - - - - d9ea2d76 by mangoiv at 2026-06-13T04:41:51-04:00 libraries/process: bump submodule to v1.6.30.0 - bump the submodule to the appropriate tag - suppress benign warning resulting from the change - - - - - 6ebaaba3 by David Eichmann at 2026-06-13T04:42:37-04:00 ghc-toolchain: don't throw when candidate executables are not found Fixes #27369 - - - - - 6c65e1e1 by David Eichmann at 2026-06-13T04:43:23-04:00 CI: lint-changelog checks for no-changelog label in script instead of rules - - - - - bab37cc6 by konsumlamm at 2026-06-13T19:10:21+02:00 Implement CLC proposal #378 Add `Data.Double` and `Data.Float` modules Document that GHC uses IEEE 754 - - - - - fb5246ad by fendor at 2026-06-15T18:07:23-04:00 Drop `preloadClosure` from `UnitState` It is always hard-coded to the same value. Backpack Unit instantiation isn't using it any more. Allows us to simplify the API and get rid of `improveUnit`. - - - - - 291ce3aa by ARATA Mizuki at 2026-06-15T18:08:26-04:00 RISC-V NCG: Zero-extend the result of castFloatToWord32 According to the ISA manual, FMV.X.W sign-extends the result. We need to truncate the result to avoid creating an exotic Word32 value. Fixes #27300 - - - - - 011be91f by ARATA Mizuki at 2026-06-15T18:08:26-04:00 RISC-V NCG: Treat d28-d31 (ft8-ft11) as caller-saved According to the calling convention, the registers d28-d31 (ft8-ft11) are caller-saved. Fixes #27306 - - - - - e8a54713 by ARATA Mizuki at 2026-06-15T18:08:26-04:00 RISC-V NCG: Set rounding mode when emitting `truncate` If we omit the rounding mode for `fcvt`, `dyn` will be used. We do not want that for `truncate`, so we set `rtz`. In other places, we set `rne` because we do not use the dynamic rounding mode. Fixes #27303 - - - - - 9438bec7 by Zubin Duggal at 2026-06-15T18:09:11-04:00 rts: fix validate build with gcc 16. `__attribute__((regparm(1)))` is ignored on x86_64 and now gcc warns that it is ignored: rts/sm/Evac.h:35:1: error: error: ‘regparm’ attribute ignored [-Werror=attributes] See https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=ccead81bbc39668376eb5cf47066a… Fixes #27366 - - - - - 893e6133 by Andrew Lelechenko at 2026-06-15T23:55:36+01:00 base: more NonEmpty zips CLC proposal: https://github.com/haskell/core-libraries-committee/issues/409 - - - - - 1314f2fd by David Eichmann at 2026-06-16T05:46:52-04:00 Hadrian: fix ghc-internal .def file name - - - - - 7f72bcb3 by mangoiv at 2026-06-16T05:47:39-04:00 compiler: ignore camelCase and Eta reduce hlint hints These do not cohere with the style used in GHC. After disabling them, hlint lints are much less noisy again. - - - - - 842bef9f by Alan Zimmerman at 2026-06-16T05:48:25-04:00 EPA: Use standard type family declaration for Anno - - - - - f6d30767 by Wolfgang Jeltsch at 2026-06-16T15:32:34-04:00 Fix two issues in the documentation of pipeline interruption One issue is a typo (“interreuptible”), the other one the lack of an end of a sentence, which has been reconstructed from the message of 633bbc1fd4762a2bb73ba1c5b9e0c279f1dd3c40, the commit that introduced said documentation. - - - - - a3fa10e0 by Christian Georgii at 2026-06-16T15:33:26-04:00 Find plugins in sibling home units in multiple-home-unit sessions In a multiple-home-unit session (e.g. `cabal repl --enable-multi-repl` or HLS), enabling a plugin with -fplugin that is defined in (or reexported by) another home unit failed with a "hidden package" error. The plugin module finder only searched the current home unit and the registered external packages, never the sibling home units. findPluginModuleNoHsc now searches the home units that the current home unit depends on, following module reexports and respecting hidden modules, exactly as ordinary import resolution does in findImportedModuleNoHsc. To avoid two divergent copies of this logic, the shared home-unit search (the current home unit first, then its dependencies in priority order, with the accompanying ordering invariant) is extracted into findHomeModuleAmongDeps, which both findImportedModuleNoHsc and findPluginModuleNoHsc now call. Add testsuite/tests/driver/multipleHomeUnits/plugin01, which loads a plugin as byte-code from a sibling home unit, and plugin02, in which the consumer enables a plugin reexported by a sibling home unit without depending on the plugin's own home unit directly. Fixes #27349 - - - - - d216412b by Ian-Woo Kim at 2026-06-16T20:25:57-04:00 Make the order of usages deterministic It has been observed that the ordering of usages can be non-determinstic in parallel builds. Therefore, this contribution introduces sorting of usages based on a platform- and race-independent sorting criterion. Resolves #26877. Co-authored-by: Wolfgang Jeltsch <wolfgang(a)well-typed.com> - - - - - 8e1cc105 by Wolfgang Jeltsch at 2026-06-16T20:25:57-04:00 Change the descriptions of two existing changelog entries The descriptions now describe the changes in a user-friendly manner, as opposed to describing the contributions that led to these changes in a developer-friendly manner. - - - - - 636c1c7a by Ian Duncan at 2026-06-16T20:26:50-04:00 AArch64: use SXTH, not SXTW, for W32 signExtendReg signExtendReg was using SXTH (sign-extend halfword, 16-bit) for W32-to-W64 sign extension. This should be SXTW (sign-extend word, 32-bit). SXTH only sign-extends the lower 16 bits, producing wrong results for 32-bit values whose bit 15 differs from bit 31. Other fixes: - At sub-W64, code gen for MO_S_Mul2 should use W32 registers for SMULL source operands as per the ARM spec (SMULL Xd, Wn, Wm), and not W64. - Ensure signExtendReg uses the source width for the source operand in SXTW/SXTH/SXTB instructions. GNU as requires sxtw Xd,Wn (not sxtw Xd,Xn), while LLVM's integrated assembler on macOS is lenient. - Fix overflow flag computation for `MO_S_Mul2`. The overflow bit was exactly inverted for sub-W64 operands. Fixes #26978 and #27047 - - - - - b734c75d by Igor Ranieri at 2026-06-16T20:27:32-04:00 haddock: Update CONTRIBUTING with missing step, add missing test dependency - - - - - 7fe4f2ec by Luite Stegeman at 2026-06-17T05:35:09-04:00 tag inference: don't confuse functions with their return values inferTagRhs was mixing up taggedness for closures and return values for function closures. We really shouldn't assign TagTuple to a properly tagged function returning a tuple. We fix this by keeping track of functions (TagFun) separately from values (TagVal) and keeping track of their return value. TagFun is also used for join points. fixes #27005 - - - - - 4671c126 by Sebastian Graf at 2026-06-17T05:35:55-04:00 Seed the simplifier's in-scope set for open expressions simplifyExpr simplifies expressions typed at the GHCi prompt and the results of Template Haskell splices. Such an expression may be open: at a GHCi debugger breakpoint its free variables include RuntimeUnk skolems standing for as-yet-unknown types. The simplifier began with an in-scope set holding only the wildcard binder, so when it instantiated the unsafeCoerce# wrapper that GHCi builds around a result, it formed a substitution whose range mentioned a free skolem that was not in scope. That breaks the substitution invariant and, in a compiler built with assertions, trips substTy's sanity check. Seed the initial in-scope set with the free variables of the expression. For a closed expression this adds nothing. See Note [Seed the in-scope set for open expressions]. Fixes #17833 and its duplicate #21118. - - - - - 67d41299 by Sebastian Graf at 2026-06-18T05:18:24-04:00 Desugar a `case` scrutinee only once (#27383, #20251) In `dsExpr` for `HsCase` we desugared the scrutinee /twice/: once to build the Core `case` itself, and again inside `matchWrapper`, which re-desugared the source scrutinee (via `addHsScrutTmCs`) purely to record long-distance information for the pattern-match checker. For a single `case` that is merely wasteful. But for nested cases it is catastrophic. Consider case (case (case e of ... ) of ... ) of ... Desugaring the outer scrutinee desugars the middle `case` twice, each of which desugars the inner `case` twice, and so on. The work doubles at every level, so desugaring takes O(2^n) time in the nesting depth. That is the blowup reported in #27383; it is also what makes the machine-generated program in #20251 take an age to compile. The fix is simple. `matchWrapper` is handed the scrutinee anyway, so we give it the Core expression we have /already/ desugared, and record the long-distance term constraint with `addCoreScrutTmCs` instead of re-desugaring from source. This is just what `matchSinglePatVar` already does for single-pattern matches. So: * `matchWrapper` now takes `Maybe [CoreExpr]` rather than `Maybe [LHsExpr GhcTc]`. * The `HsCase` equation of `dsExpr` passes the already-desugared `core_discrim`; the arrow desugarer passes its match variables. * `addHsScrutTmCs` had no other use, so it is gone. Desugaring is now linear in the nesting depth. (The coverage checker still runs `simpleOptExpr` over each scrutinee, which leaves the total at O(n^2); that is ample.) The long-distance information itself is unchanged: the checker sees precisely the Core that backs the generated code. Test: deSugar/should_compile/T27383 - - - - - fa5defde by Rodrigo Mesquita at 2026-06-18T05:19:11-04:00 fix: Save FastStrings in the PMC There is no point in adding the unique to the occurrence FastString we create, since it is part of the Id anyway. Adding it to the FastString, meant each FastString was unique unnecessarily! In a separate branch, running the compiler on test `InstanceMatching` observed 30000 `FastString`s created by this code path. Plus, `fsLit "pm"` follows the existing pattern in `mkPmId`. - - - - - 4efb4a66 by Alan Zimmerman at 2026-06-18T14:41:14-04:00 TTG: Add extension points to HsConDetails Extend HsConDetails as data HsConDetails p arg rec = PrefixCon !(XPrefixCon p) [arg] -- C @t1 @t2 p1 p2 p3 | RecCon !(XRecCon p) rec -- C { x = p1, y = p2 } | InfixCon !(XInfixCon p) arg arg -- p1 `C` p2 | XHsConDetails !(XXHsConDetails p) type family XPrefixCon p type family XRecCon p type family XInfixCon p type family XXHsConDetails p - - - - - c8d27dd4 by Simon Jakobi at 2026-06-18T14:41:59-04:00 CI: quiet submodule clean output in after_script and setup The clean and cleanup_submodules functions ran 'git submodule foreach git clean -xdf', flooding the job log with 'Entering ...' and 'Removing ...' lines. Pass --quiet to 'git submodule' and -q to 'git clean' to drop the success output; errors are still reported. Co-Authored-By: Claude Opus 4.8 <noreply(a)anthropic.com> - - - - - 5ef7b129 by Simon Hengel at 2026-06-22T04:08:12+07:00 haddock: For ordered lists, only pay attention to the first list index This partially reverts 0a645049b89c8fe49169b7af073732a93011fe25. This addresses: https://github.com/haskell/haddock/pull/1407#issuecomment-2178079566 - - - - - 230 changed files: - .gitlab-ci.yml - .gitlab/ci.sh - + changelog.d/T17833 - + changelog.d/T26978 - + changelog.d/T27046 - + changelog.d/T27047 - + changelog.d/T27225 - + changelog.d/T27308 - + changelog.d/T27317 - + changelog.d/T27359 - + changelog.d/deterministic-usage-order - + changelog.d/fix-exponential-case-desugar-27383 - + changelog.d/fix-plugin-finder-multi-home-unit.md - changelog.d/hadrian-response-files.md - + changelog.d/hadrian-stale-package-confs-26661 - changelog.d/module-graph-reuse-in-downsweep - changelog.d/more-efficient-home-unit-imports-finding - + changelog.d/tag-inference-27005 - + changelog.d/tool-messages-27370 - compiler/.hlint.yaml - compiler/GHC/CmmToAsm/AArch64/CodeGen.hs - compiler/GHC/CmmToAsm/AArch64/Instr.hs - compiler/GHC/CmmToAsm/AArch64/Ppr.hs - compiler/GHC/CmmToAsm/RV64/CodeGen.hs - compiler/GHC/CmmToAsm/RV64/Instr.hs - compiler/GHC/CmmToAsm/RV64/Ppr.hs - compiler/GHC/CmmToAsm/RV64/Regs.hs - compiler/GHC/Core/Opt/Simplify.hs - compiler/GHC/Core/Type.hs - compiler/GHC/Core/Utils.hs - compiler/GHC/Data/List/NonEmpty.hs - compiler/GHC/Driver/Backend.hs - compiler/GHC/Driver/Backpack.hs - compiler/GHC/Hs/Binds.hs - compiler/GHC/Hs/Decls.hs - compiler/GHC/Hs/Instances.hs - compiler/GHC/Hs/Pat.hs - compiler/GHC/Hs/Type.hs - compiler/GHC/Hs/Utils.hs - compiler/GHC/HsToCore/Arrows.hs - compiler/GHC/HsToCore/Docs.hs - compiler/GHC/HsToCore/Expr.hs - compiler/GHC/HsToCore/Match.hs - compiler/GHC/HsToCore/Match.hs-boot - compiler/GHC/HsToCore/Match/Constructor.hs - compiler/GHC/HsToCore/Pmc.hs - compiler/GHC/HsToCore/Pmc/Desugar.hs - compiler/GHC/HsToCore/Pmc/Solver.hs - compiler/GHC/HsToCore/Quote.hs - compiler/GHC/HsToCore/Ticks.hs - compiler/GHC/HsToCore/Usage.hs - compiler/GHC/Iface/Ext/Ast.hs - compiler/GHC/Iface/Load.hs - compiler/GHC/Iface/Recomp.hs - compiler/GHC/Parser.y - compiler/GHC/Parser/PostProcess.hs - compiler/GHC/Parser/PostProcess/Haddock.hs - compiler/GHC/Rename/Bind.hs - compiler/GHC/Rename/HsType.hs - compiler/GHC/Rename/Module.hs - compiler/GHC/Rename/Pat.hs - compiler/GHC/Rename/Utils.hs - compiler/GHC/Runtime/Debugger/Breakpoints.hs - compiler/GHC/Runtime/Eval/Types.hs - compiler/GHC/Runtime/Heap/Inspect.hs - compiler/GHC/Stg/EnforceEpt.hs - compiler/GHC/Stg/EnforceEpt/Rewrite.hs - compiler/GHC/Stg/EnforceEpt/TagSig.hs - compiler/GHC/Stg/EnforceEpt/Types.hs - compiler/GHC/SysTools/Process.hs - compiler/GHC/Tc/Deriv/Generate.hs - compiler/GHC/Tc/Gen/Pat.hs - compiler/GHC/Tc/Solver/Equality.hs - compiler/GHC/Tc/Solver/FunDeps.hs - compiler/GHC/Tc/TyCl.hs - compiler/GHC/Tc/TyCl/PatSyn.hs - compiler/GHC/Tc/TyCl/Utils.hs - compiler/GHC/Tc/Zonk/Type.hs - compiler/GHC/ThToHs.hs - compiler/GHC/Types/RepType.hs - compiler/GHC/Unit.hs - compiler/GHC/Unit/Finder.hs - compiler/GHC/Unit/Module/Deps.hs - compiler/GHC/Unit/State.hs - compiler/GHC/Unit/Types.hs - compiler/GHC/Utils/Logger.hs - compiler/Language/Haskell/Syntax/Binds.hs - compiler/Language/Haskell/Syntax/Decls.hs - compiler/Language/Haskell/Syntax/Extension.hs - compiler/Language/Haskell/Syntax/Pat.hs - compiler/Language/Haskell/Syntax/Type.hs - docs/users_guide/bugs.rst - docs/users_guide/using.rst - hadrian/build-cabal - hadrian/src/Builder.hs - hadrian/src/CommandLine.hs - hadrian/src/Hadrian/Builder/Ar.hs - hadrian/src/Hadrian/Haskell/Cabal/Parse.hs - hadrian/src/Hadrian/Utilities.hs - hadrian/src/Rules/BinaryDist.hs - hadrian/src/Rules/Rts.hs - libraries/base/base.cabal.in - libraries/base/changelog.md - + libraries/base/src/Data/Double.hs - + libraries/base/src/Data/Float.hs - libraries/base/src/Data/List/NonEmpty.hs - libraries/ghc-internal/src/GHC/Internal/Float.hs - libraries/ghc-internal/src/GHC/Internal/Lexeme.hs - libraries/process - rts/Capability.c - rts/Schedule.c - rts/Timer.c - rts/eventlog/EventLog.c - rts/eventlog/EventLog.h - rts/include/rts/OSThreads.h - rts/sm/Evac.h - testsuite/driver/testlib.py - testsuite/mk/test.mk - + testsuite/tests/codeGen/should_gen_asm/aarch64-sxth-mul2.asm - + testsuite/tests/codeGen/should_gen_asm/aarch64-sxth-mul2.cmm - + testsuite/tests/codeGen/should_gen_asm/aarch64-sxtw.asm - + testsuite/tests/codeGen/should_gen_asm/aarch64-sxtw.cmm - testsuite/tests/codeGen/should_gen_asm/all.T - testsuite/tests/codeGen/should_run/T16617.hs - testsuite/tests/codeGen/should_run/T16617.stdout - + testsuite/tests/codeGen/should_run/T27046.hs - + testsuite/tests/codeGen/should_run/T27046_cmm.cmm - + testsuite/tests/codeGen/should_run/aarch64-sxtw-cmm.cmm - + testsuite/tests/codeGen/should_run/aarch64-sxtw-run.hs - + testsuite/tests/codeGen/should_run/aarch64-sxtw-run.stdout - testsuite/tests/codeGen/should_run/all.T - testsuite/tests/core-to-stg/T14895.stderr - testsuite/tests/count-deps/CountDepsAst.stdout - testsuite/tests/count-deps/CountDepsParser.stdout - + testsuite/tests/deSugar/should_compile/T27383.hs - testsuite/tests/deSugar/should_compile/all.T - + testsuite/tests/driver/T27370/Makefile - + testsuite/tests/driver/T27370/T27370.hs - + testsuite/tests/driver/T27370/T27370.pp - + testsuite/tests/driver/T27370/T27370.stderr - + testsuite/tests/driver/T27370/all.T - + testsuite/tests/driver/multipleHomeUnits/plugin01/all.T - + testsuite/tests/driver/multipleHomeUnits/plugin01/appunit - + testsuite/tests/driver/multipleHomeUnits/plugin01/p/MyPlugin.hs - + testsuite/tests/driver/multipleHomeUnits/plugin01/pluginunit - + testsuite/tests/driver/multipleHomeUnits/plugin01/q/App.hs - + testsuite/tests/driver/multipleHomeUnits/plugin02/all.T - + testsuite/tests/driver/multipleHomeUnits/plugin02/appunit - + testsuite/tests/driver/multipleHomeUnits/plugin02/p/MyPlugin.hs - + testsuite/tests/driver/multipleHomeUnits/plugin02/pluginunit - + testsuite/tests/driver/multipleHomeUnits/plugin02/q/App.hs - + testsuite/tests/driver/multipleHomeUnits/plugin02/r/RexLib.hs - + testsuite/tests/driver/multipleHomeUnits/plugin02/reexportunit - testsuite/tests/ghc-api/exactprint/Test20239.stderr - testsuite/tests/ghci.debugger/scripts/all.T - testsuite/tests/haddock/should_compile_flag_haddock/T24221.stderr - testsuite/tests/interface-stability/base-exports.stdout - testsuite/tests/interface-stability/base-exports.stdout-javascript-unknown-ghcjs - testsuite/tests/interface-stability/base-exports.stdout-mingw32 - testsuite/tests/parser/should_compile/DumpParsedAst.stderr - testsuite/tests/parser/should_compile/DumpRenamedAst.stderr - testsuite/tests/parser/should_compile/T14189.stderr - testsuite/tests/parser/should_compile/T20452.stderr - + testsuite/tests/perf/compiler/T26426.hs - testsuite/tests/perf/compiler/all.T - testsuite/tests/printer/Test24533.stdout - + testsuite/tests/profiling/should_run/T27225.hs - + testsuite/tests/profiling/should_run/T27225.stdout - + testsuite/tests/profiling/should_run/T27225b.hs - + testsuite/tests/profiling/should_run/T27225b.stdout - testsuite/tests/profiling/should_run/all.T - testsuite/tests/profiling/should_run/caller-cc/CallerCc1.prof.sample - testsuite/tests/profiling/should_run/callstack001.stdout - testsuite/tests/profiling/should_run/scc001.prof.sample - testsuite/tests/rts/T27131.hs - testsuite/tests/rts/T27131.stdout - + testsuite/tests/simplCore/should_compile/T4081.hs - + testsuite/tests/simplCore/should_compile/T4081.stderr - testsuite/tests/simplCore/should_compile/T4201.stdout - testsuite/tests/simplCore/should_compile/all.T - + testsuite/tests/simplCore/should_run/T27005.hs - + testsuite/tests/simplCore/should_run/T27005.stdout - + testsuite/tests/simplCore/should_run/T27005_aux.hs - testsuite/tests/simplCore/should_run/all.T - testsuite/tests/simplStg/should_compile/T24806.hs - testsuite/tests/simplStg/should_compile/T24806.stderr - + testsuite/tests/simplStg/should_compile/T27005b.hs - + testsuite/tests/simplStg/should_compile/T27005b.stderr - testsuite/tests/simplStg/should_compile/all.T - testsuite/tests/simplStg/should_compile/inferTags004.hs - testsuite/tests/simplStg/should_compile/inferTags004.stderr - + testsuite/tests/simplStg/should_run/T27005a.hs - + testsuite/tests/simplStg/should_run/T27005a.stdout - testsuite/tests/simplStg/should_run/all.T - utils/check-exact/ExactPrint.hs - utils/check-exact/Main.hs - utils/check-exact/Transform.hs - utils/ghc-toolchain/src/GHC/Toolchain/Program.hs - utils/ghc-toolchain/src/GHC/Toolchain/Utils.hs - utils/haddock/CONTRIBUTING.md - utils/haddock/haddock-api/haddock-api.cabal - utils/haddock/haddock-api/src/Haddock.hs - utils/haddock/haddock-api/src/Haddock/Backends/Hoogle.hs - utils/haddock/haddock-api/src/Haddock/Backends/Hyperlinker.hs - utils/haddock/haddock-api/src/Haddock/Backends/LaTeX.hs - utils/haddock/haddock-api/src/Haddock/Backends/Xhtml.hs - utils/haddock/haddock-api/src/Haddock/Backends/Xhtml/Decl.hs - utils/haddock/haddock-api/src/Haddock/Backends/Xhtml/DocMarkup.hs - utils/haddock/haddock-api/src/Haddock/Convert.hs - utils/haddock/haddock-api/src/Haddock/GhcUtils.hs - utils/haddock/haddock-api/src/Haddock/Interface/Create.hs - utils/haddock/haddock-api/src/Haddock/Interface/Json.hs - utils/haddock/haddock-api/src/Haddock/Interface/LexParseRn.hs - utils/haddock/haddock-api/src/Haddock/Interface/Rename.hs - utils/haddock/haddock-api/src/Haddock/InterfaceFile.hs - utils/haddock/haddock-api/src/Haddock/Options.hs - utils/haddock/haddock-api/src/Haddock/Types.hs - utils/haddock/haddock-api/src/Haddock/Utils.hs - utils/haddock/haddock-library/src/Documentation/Haddock/Doc.hs - utils/haddock/haddock-library/src/Documentation/Haddock/Markup.hs - utils/haddock/haddock-library/src/Documentation/Haddock/Parser.hs - utils/haddock/haddock-library/src/Documentation/Haddock/Types.hs - utils/haddock/haddock-library/test/Documentation/Haddock/ParserSpec.hs - utils/haddock/haddock-test/haddock-test.cabal - utils/haddock/html-test/ref/Bug313.html - utils/haddock/html-test/ref/Hash.html - utils/haddock/html-test/ref/Nesting.html - utils/haddock/html-test/ref/Test.html - utils/haddock/html-test/ref/TypeFamilies3.html - utils/haddock/html-test/src/Test.hs The diff was not included because it is too large. View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/4d2e1b16e8f480791e789c90652641… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/4d2e1b16e8f480791e789c90652641… You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][wip/sol/interactive-error-hints] Add a flag to control GHCi specific error hints (close #27409)
by Simon Hengel (＠sol) 22 Jun '26

22 Jun '26

Simon Hengel pushed to branch wip/sol/interactive-error-hints at Glasgow Haskell Compiler / GHC Commits: 1a4e8e07 by Simon Hengel at 2026-06-22T04:06:46+07:00 Add a flag to control GHCi specific error hints (close #27409) - - - - - 11 changed files: - + changelog.d/interactive-error-hints - compiler/GHC/Driver/DynFlags.hs - compiler/GHC/Driver/Flags.hs - compiler/GHC/Driver/Session.hs - compiler/GHC/Types/Hint/Ppr.hs - compiler/GHC/Utils/Outputable.hs - docs/users_guide/ghci.rst - ghc/GHCi/UI/Exception.hs - ghc/Main.hs - testsuite/tests/ghci/prog-mhu002/prog-mhu002c.stdout - testsuite/tests/ghci/scripts/ghci024.stdout Changes: ===================================== changelog.d/interactive-error-hints ===================================== @@ -0,0 +1,6 @@ +section: compiler +synopsis: + Add flags `-finteractive-error-hints` / `-fno-interactive-error-hints` that + control whether GHCi specific error hints are printed. +issues: #27409 +mrs: !16225 ===================================== compiler/GHC/Driver/DynFlags.hs ===================================== @@ -1570,6 +1570,7 @@ initSDocContext dflags style = SDC , sdocLineLength = pprCols dflags , sdocCanUseUnicode = useUnicode dflags , sdocPrintErrIndexLinks = overrideWith (canUseErrorLinks dflags) (useErrorLinks dflags) + , sdocInteractiveErrorHints = gopt Opt_InteractiveErrorHints dflags , sdocHexWordLiterals = gopt Opt_HexWordLiterals dflags , sdocPprDebug = dopt Opt_D_ppr_debug dflags , sdocPrintUnicodeSyntax = gopt Opt_PrintUnicodeSyntax dflags ===================================== compiler/GHC/Driver/Flags.hs ===================================== @@ -861,6 +861,7 @@ data GeneralFlag -- Error message suppression | Opt_ShowErrorContext + | Opt_InteractiveErrorHints -- Object code determinism | Opt_ObjectDeterminism ===================================== compiler/GHC/Driver/Session.hs ===================================== @@ -2665,6 +2665,7 @@ fFlagsDeps = [ (addWarn "-compact-unwind is only implemented by the darwin platform. Ignoring.") return dflags)), flagSpec "show-error-context" Opt_ShowErrorContext, + flagSpec "interactive-error-hints" Opt_InteractiveErrorHints, flagSpec "cmm-thread-sanitizer" Opt_CmmThreadSanitizer, flagSpec "split-sections" Opt_SplitSections, flagSpec "break-points" Opt_InsertBreakpoints, ===================================== compiler/GHC/Types/Hint/Ppr.hs ===================================== @@ -43,19 +43,44 @@ instance Outputable GhcHint where -> case extHint of SuggestSingleExtension extraUserInfo ext -> ("Perhaps you intended to use" <+> extension_with_implied ext) - $$ extraUserInfo + $$ interactiveErrorHints [ext] extraUserInfo False SuggestAnyExtension extraUserInfo exts -> (enable "any" <+> unquotedListWith "or" (map implied exts)) - $$ extraUserInfo + $$ interactiveErrorHints exts extraUserInfo True SuggestExtensions extraUserInfo exts -> (enable "all" <+> unquotedListWith "and" (map implied exts)) - $$ extraUserInfo + $$ interactiveErrorHints exts extraUserInfo False SuggestExtensionInOrderTo extraUserInfo ext -> ("Use" <+> extension_with_implied ext) - $$ extraUserInfo + $$ interactiveErrorHints [ext] extraUserInfo False where extension_with_implied ext = "the" <+> quotes (ppr ext) <+> "extension" <+> pprImpliedExtensions ext implied ext = quotes (ppr ext) <+> pprImpliedExtensions ext enable any_or_all = "Enable" <+> any_or_all <+> "of the following extensions" <> colon + + interactiveErrorHints :: [LangExt.Extension] -> SDoc -> Bool -> SDoc + interactiveErrorHints exts doc enable_any = sdocOption sdocInteractiveErrorHints $ \ case + True -> suggestSetExt exts doc enable_any + False -> doc + + -- Suggest enabling extension with :set -X<ext> + -- SuggestAnyExtension will be on multiple lines so the user can select which to enable without editing + suggestSetExt :: [LangExt.Extension] -> SDoc -> Bool -> SDoc + suggestSetExt exts doc enable_any = doc $$ hang header 2 exts_cmds + where + header = text "You may enable" <+> which <+> text "language extension" <> plural exts <+> text "in GHCi with:" + which + | [ _ext ] <- exts + = text "this" + | otherwise + = if enable_any + then text "these" + else text "all of these" + exts_cmds + | enable_any + = vcat $ map (\ext -> text ":set -X" <> ppr ext) exts + | otherwise + = text ":set" <> hcat (map (\ext -> text " -X" <> ppr ext) exts) + SuggestCorrectPragmaName suggestions -> text "Perhaps you meant" <+> quotedListWithOr (map text suggestions) SuggestMissingDo ===================================== compiler/GHC/Utils/Outputable.hs ===================================== @@ -398,6 +398,7 @@ data SDocContext = SDC -- ^ True if Unicode encoding is supported -- and not disabled by GHC_NO_UNICODE environment variable , sdocPrintErrIndexLinks :: !Bool + , sdocInteractiveErrorHints :: !Bool , sdocHexWordLiterals :: !Bool , sdocPprDebug :: !Bool , sdocPrintUnicodeSyntax :: !Bool @@ -466,6 +467,7 @@ defaultSDocContext = SDC , sdocLineLength = defaultSDocCols , sdocCanUseUnicode = False , sdocPrintErrIndexLinks = False + , sdocInteractiveErrorHints = False , sdocHexWordLiterals = False , sdocPprDebug = False , sdocPrintUnicodeSyntax = False ===================================== docs/users_guide/ghci.rst ===================================== @@ -2114,6 +2114,27 @@ mostly obvious. If disabled, only the target given last on the command line interface will be added to interactive context of the GHCi session. +.. ghc-flag:: -finteractive-error-hints + :shortdesc: Print GHCi specific error hints. + :type: dynamic + :reverse: -fno-interactive-error-hints + :category: + + :default: on + :since: XXX + + By default, GHCi extends error hints with GHCi specific instructions. + + Example: + + .. code-block:: none + + Perhaps you intended to use the ‘BlockArguments’ extension + You may enable this language extension in GHCi with: + :set -XBlockArguments + + This can be disabled with `-fno-interactive-error-hints`. + Packages ~~~~~~~~ ===================================== ghc/GHCi/UI/Exception.hs ===================================== @@ -23,8 +23,6 @@ import GHC.Driver.Errors.Types import GHC.Iface.Errors.Ppr import GHC.Iface.Errors.Types -import qualified GHC.LanguageExtensions as LangExt - import GHC.Tc.Errors.Ppr import GHC.Tc.Errors.Types @@ -137,7 +135,7 @@ instance Diagnostic GhciMessage where GhciUnknownMessage m -> diagnosticReason m diagnosticHints = \case - GhciGhcMessage m -> map GhciGhcHint (ghciDiagnosticHints m) + GhciGhcMessage m -> map GhciGhcHint (diagnosticHints m) GhciCommandMessage m -> map GhciCommandHint (diagnosticHints m) GhciUnknownMessage m -> diagnosticHints m @@ -146,40 +144,6 @@ instance Diagnostic GhciMessage where GhciCommandMessage m -> diagnosticCode m GhciUnknownMessage m -> diagnosticCode m - --- | Modifications to hint messages which we want to display in GHCi. -ghciDiagnosticHints :: GhcMessage -> [GhcHint] -ghciDiagnosticHints msg = map modifyHintForGHCi (diagnosticHints msg) - where - modifyHintForGHCi :: GhcHint -> GhcHint - modifyHintForGHCi = \case - SuggestExtension extHint -> SuggestExtension $ modifyExtHintForGHCi extHint - hint -> hint - modifyExtHintForGHCi :: LanguageExtensionHint -> LanguageExtensionHint - modifyExtHintForGHCi = \case - SuggestSingleExtension doc ext -> SuggestSingleExtension (suggestSetExt [ext] doc False) ext - SuggestExtensionInOrderTo doc ext -> SuggestExtensionInOrderTo (suggestSetExt [ext] doc False) ext - SuggestAnyExtension doc exts -> SuggestAnyExtension (suggestSetExt exts doc True ) exts - SuggestExtensions doc exts -> SuggestExtensions (suggestSetExt exts doc False) exts - -- Suggest enabling extension with :set -X<ext> - -- SuggestAnyExtension will be on multiple lines so the user can select which to enable without editing - suggestSetExt :: [LangExt.Extension] -> SDoc -> Bool -> SDoc - suggestSetExt exts doc enable_any = doc $$ hang header 2 exts_cmds - where - header = text "You may enable" <+> which <+> text "language extension" <> plural exts <+> text "in GHCi with:" - which - | [ _ext ] <- exts - = text "this" - | otherwise - = if enable_any - then text "these" - else text "all of these" - exts_cmds - | enable_any - = vcat $ map (\ext -> text ":set -X" <> ppr ext) exts - | otherwise - = text ":set" <> hcat (map (\ext -> text " -X" <> ppr ext) exts) - -- | Modifications to error messages which we want to display in GHCi ghciDiagnosticMessage :: GhcMessageOpts -> GhcMessage -> DecoratedSDoc ghciDiagnosticMessage ghc_opts msg = ===================================== ghc/Main.hs ===================================== @@ -199,6 +199,7 @@ main' postLoadMode units dflags0 args flagWarnings = do | DoRun <- postLoadMode = def_ghci_flags | otherwise = dflags1 where def_ghci_flags = dflags1 `gopt_set` Opt_ImplicitImportQualified + `gopt_set` Opt_InteractiveErrorHints `gopt_set` Opt_IgnoreOptimChanges `gopt_set` Opt_IgnoreHpcChanges -- Setting this by default has the nice effect that ===================================== testsuite/tests/ghci/prog-mhu002/prog-mhu002c.stdout ===================================== @@ -14,6 +14,7 @@ other dynamic, non-language, flag settings: -fno-unoptimized-core-for-interpreter -fshow-warning-groups -fprefer-byte-code + -finteractive-error-hints -fbreak-points warning settings: -Wpattern-namespace-specifier @@ -33,6 +34,7 @@ other dynamic, non-language, flag settings: -fno-unoptimized-core-for-interpreter -fshow-warning-groups -fprefer-byte-code + -finteractive-error-hints -fbreak-points warning settings: -Wpattern-namespace-specifier @@ -50,6 +52,7 @@ other dynamic, non-language, flag settings: -fno-unoptimized-core-for-interpreter -fshow-warning-groups -fprefer-byte-code + -finteractive-error-hints -fbreak-points warning settings: -Wpattern-namespace-specifier @@ -67,6 +70,7 @@ other dynamic, non-language, flag settings: -fno-unoptimized-core-for-interpreter -fshow-warning-groups -fprefer-byte-code + -finteractive-error-hints -fbreak-points warning settings: -Wpattern-namespace-specifier @@ -84,6 +88,7 @@ other dynamic, non-language, flag settings: -fno-unoptimized-core-for-interpreter -fshow-warning-groups -fprefer-byte-code + -finteractive-error-hints -fbreak-points warning settings: -Wpattern-namespace-specifier ===================================== testsuite/tests/ghci/scripts/ghci024.stdout ===================================== @@ -12,6 +12,7 @@ other dynamic, non-language, flag settings: -fimplicit-import-qualified -fshow-warning-groups -fprefer-byte-code + -finteractive-error-hints -fbreak-points warning settings: -Wpattern-namespace-specifier View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/1a4e8e079551301113fcf5266d45811… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/1a4e8e079551301113fcf5266d45811… You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc] Pushed new branch wip/drop-rts-exception-binds
by Ben Gamari (＠bgamari) 22 Jun '26

22 Jun '26

Ben Gamari pushed new branch wip/drop-rts-exception-binds at Glasgow Haskell Compiler / GHC -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/tree/wip/drop-rts-exception-binds You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][wip/stm-mvar-deadlock-backtrace] 3 commits: Throw nontermination exceptions via `throw`
by Ben Gamari (＠bgamari) 22 Jun '26

22 Jun '26

Ben Gamari pushed to branch wip/stm-mvar-deadlock-backtrace at Glasgow Haskell Compiler / GHC Commits: b709d077 by Ben Gamari at 2026-06-21T17:01:08-04:00 Throw nontermination exceptions via `throw` This ensures that the exception that results gets the usual backtrace annotations. This is a first step to #21878. - - - - - b8a14364 by Ben Gamari at 2026-06-21T17:01:10-04:00 compiler: Report backtraces in MVar and STM deadlocks Apply the same treatment previously given to Nontermination exceptions to MVar and STM deadlock exceptions, using `throw` instead of ad-hoc throwing with `throwToSingleThread` to ensure that the usual backtrace machinery is involved. Related to #21877. - - - - - e3f3e0a6 by Ben Gamari at 2026-06-21T17:01:10-04:00 testsuite: Add tests for deadlock backtraces - - - - - 17 changed files: - + changelog.d/builtin-exception-backtraces - libraries/ghc-internal/include/RtsIfaceSymbols.h - libraries/ghc-internal/src/GHC/Internal/Control/Exception/Base.hs - libraries/ghc-internal/src/GHC/Internal/IO/Exception.hs - rts/Prelude.h - rts/RaiseAsync.c - rts/RaiseAsync.h - rts/RtsStartup.c - rts/Schedule.c - rts/include/rts/RtsToHsIface.h - testsuite/tests/rts/LoopBacktrace.stderr - + testsuite/tests/rts/MVarDeadlockBacktrace.hs - + testsuite/tests/rts/MVarDeadlockBacktrace.stderr - + testsuite/tests/rts/STMDeadlockBacktrace.hs - + testsuite/tests/rts/STMDeadlockBacktrace.stderr - testsuite/tests/rts/T2783.stderr - testsuite/tests/rts/all.T Changes: ===================================== changelog.d/builtin-exception-backtraces ===================================== @@ -0,0 +1,10 @@ +section: rts +synopsis: Non-termination and deadlock exceptions now have backtrace annotations +issues: #21878 +mrs: !16158 +description: { + The `BlockedOnMVar`, `BlockedOnSTM`, and `NonTermination` exceptions + (the latter being the infamous `<<loop>>` error) now include `Backtrace` + `ExceptionAnnotations`, like exceptions thrown from user-written Haskell. +} + ===================================== libraries/ghc-internal/include/RtsIfaceSymbols.h ===================================== @@ -15,12 +15,12 @@ CLOSURE(GHCziInternalziWeakziFinalizze, runFinalizzerBatch_closure) CLOSURE(GHCziInternalziIOziException, stackOverflow_closure) CLOSURE(GHCziInternalziIOziException, heapOverflow_closure) CLOSURE(GHCziInternalziIOziException, allocationLimitExceeded_closure) -CLOSURE(GHCziInternalziIOziException, blockedIndefinitelyOnMVar_closure) -CLOSURE(GHCziInternalziIOziException, blockedIndefinitelyOnSTM_closure) +CLOSURE(GHCziInternalziIOziException, blockedIndefinitelyOnMVarError_closure) +CLOSURE(GHCziInternalziIOziException, blockedIndefinitelyOnSTMError_closure) CLOSURE(GHCziInternalziIOziException, cannotCompactFunction_closure) CLOSURE(GHCziInternalziIOziException, cannotCompactPinned_closure) CLOSURE(GHCziInternalziIOziException, cannotCompactMutable_closure) -CLOSURE(GHCziInternalziControlziExceptionziBase, nonTermination_closure) +CLOSURE(GHCziInternalziControlziExceptionziBase, nonTerminationError_closure) CLOSURE(GHCziInternalziControlziExceptionziBase, nestedAtomically_closure) CLOSURE(GHCziInternalziControlziExceptionziBase, noMatchingContinuationPrompt_closure) #if defined(mingw32_HOST_OS) ===================================== libraries/ghc-internal/src/GHC/Internal/Control/Exception/Base.hs ===================================== @@ -108,7 +108,9 @@ module GHC.Internal.Control.Exception.Base ( impossibleError, impossibleConstraintError, nonExhaustiveGuardsError, patError, noMethodBindingError, typeError, - nonTermination, nestedAtomically, noMatchingContinuationPrompt, + nonTermination, nonTerminationError, + nestedAtomically, + noMatchingContinuationPrompt, ) where import GHC.Internal.Base ( @@ -448,6 +450,9 @@ impossibleConstraintError s = errorWithoutStackTrace (unpackCStringUtf8# s) -- GHC's RTS calls this +nonTerminationError :: IO () +nonTerminationError = throwIO NonTermination + nonTermination :: SomeException nonTermination = toException NonTermination ===================================== libraries/ghc-internal/src/GHC/Internal/IO/Exception.hs ===================================== @@ -24,8 +24,12 @@ ----------------------------------------------------------------------------- module GHC.Internal.IO.Exception ( - BlockedIndefinitelyOnMVar(..), blockedIndefinitelyOnMVar, - BlockedIndefinitelyOnSTM(..), blockedIndefinitelyOnSTM, + BlockedIndefinitelyOnMVar(..), + blockedIndefinitelyOnMVar, + blockedIndefinitelyOnMVarError, + BlockedIndefinitelyOnSTM(..), + blockedIndefinitelyOnSTM, + blockedIndefinitelyOnSTMError, Deadlock(..), AllocationLimitExceeded(..), allocationLimitExceeded, AssertionFailed(..), @@ -84,6 +88,9 @@ instance Exception BlockedIndefinitelyOnMVar instance Show BlockedIndefinitelyOnMVar where showsPrec _ BlockedIndefinitelyOnMVar = showString "thread blocked indefinitely in an MVar operation" +blockedIndefinitelyOnMVarError :: IO () -- for the RTS +blockedIndefinitelyOnMVarError = throwIO BlockedIndefinitelyOnMVar + blockedIndefinitelyOnMVar :: SomeException -- for the RTS blockedIndefinitelyOnMVar = toException BlockedIndefinitelyOnMVar @@ -100,6 +107,9 @@ instance Exception BlockedIndefinitelyOnSTM instance Show BlockedIndefinitelyOnSTM where showsPrec _ BlockedIndefinitelyOnSTM = showString "thread blocked indefinitely in an STM transaction" +blockedIndefinitelyOnSTMError :: IO () -- for the RTS +blockedIndefinitelyOnSTMError = throwIO BlockedIndefinitelyOnSTM + blockedIndefinitelyOnSTM :: SomeException -- for the RTS blockedIndefinitelyOnSTM = toException BlockedIndefinitelyOnSTM ===================================== rts/Prelude.h ===================================== @@ -53,12 +53,12 @@ extern StgClosure ZCMain_main_closure; #define stackOverflow_closure ghc_hs_iface->stackOverflow_closure #define heapOverflow_closure ghc_hs_iface->heapOverflow_closure #define allocationLimitExceeded_closure ghc_hs_iface->allocationLimitExceeded_closure -#define blockedIndefinitelyOnMVar_closure ghc_hs_iface->blockedIndefinitelyOnMVar_closure -#define blockedIndefinitelyOnSTM_closure ghc_hs_iface->blockedIndefinitelyOnSTM_closure +#define blockedIndefinitelyOnMVarError_closure ghc_hs_iface->blockedIndefinitelyOnMVarError_closure +#define blockedIndefinitelyOnSTMError_closure ghc_hs_iface->blockedIndefinitelyOnSTMError_closure #define cannotCompactFunction_closure ghc_hs_iface->cannotCompactFunction_closure #define cannotCompactPinned_closure ghc_hs_iface->cannotCompactPinned_closure #define cannotCompactMutable_closure ghc_hs_iface->cannotCompactMutable_closure -#define nonTermination_closure ghc_hs_iface->nonTermination_closure +#define nonTerminationError_closure ghc_hs_iface->nonTerminationError_closure #define nestedAtomically_closure ghc_hs_iface->nestedAtomically_closure #define absentSumFieldError_closure ghc_hs_iface->absentSumFieldError_closure #define underflowException_closure ghc_hs_iface->underflowException_closure ===================================== rts/RaiseAsync.c ===================================== @@ -87,6 +87,55 @@ suspendComputation (Capability *cap, StgTSO *tso, StgUpdateFrame *stop_here) throwToSingleThreaded__ (cap, tso, NULL, false, stop_here); } +/* ----------------------------------------------------------------------------- + scheduleRaiseViaIO + + Schedule `tso` to raise an exception by running `io_action`, an IO () that + performs `throwIO`. Unlike throwToSingleThreaded (which injects an exception + *value* via raiseAsync), the exception is raised by throwIO *within* the + thread, so it acquires a backtrace of the thread's stack. This is used by + resurrectThreads to deliver the "blocked indefinitely" exceptions + (BlockedIndefinitelyOnMVar, BlockedIndefinitelyOnSTM, NonTermination). + + We push a "run this IO action" frame on top of the thread's existing + (suspended) stack and make it runnable; when the thread runs, throwIO raises + the exception and its own stack unwinding handles any CATCH_FRAME / + ATOMICALLY_FRAME (e.g. aborting a blocked STM transaction). + + removeFromQueues takes care of unlinking the thread from any blocking queue + (notably the MVar blocked queue) and appends it to the run queue. As with + throwToSingleThreaded, the caller must own the TSO (e.g. hold all + capabilities during GC); in particular this relies on the thread not being + scheduled between removeFromQueues' enqueue and our stack push. + -------------------------------------------------------------------------- */ + +void +scheduleRaiseViaIO (Capability *cap, StgTSO *tso, StgClosure *io_action) +{ + // Thread already dead? + if (tso->what_next == ThreadComplete || tso->what_next == ThreadKilled) { + return; + } + + // Unlink from any blocking queues; sets why_blocked = NotBlocked and + // appends the thread to the run queue. + removeFromQueues(cap, tso); + + StgStack *stack = tso->stackobj; + + // We are about to mutate the stack, so dirty it for the GC write barrier + // (resurrectThreads runs right after GC). + dirty_TSO(cap, tso); + dirty_STACK(cap, stack); + + // Push a frame that enters `io_action` and applies the resulting IO action + // to the void (RealWorld) argument: [stg_enter_info, io_action, stg_ap_v_info] + stack->sp -= 3; + stack->sp[0] = (W_)&stg_enter_info; + stack->sp[1] = (W_)io_action; + stack->sp[2] = (W_)&stg_ap_v_info; +} + /* ----------------------------------------------------------------------------- throwToSelf ===================================== rts/RaiseAsync.h ===================================== @@ -38,6 +38,10 @@ void suspendComputation (Capability *cap, StgTSO *tso, StgUpdateFrame *stop_here); +void scheduleRaiseViaIO (Capability *cap, + StgTSO *tso, + StgClosure *io_action); + MessageThrowTo *throwTo (Capability *cap, // the Capability we hold StgTSO *source, StgTSO *target, ===================================== rts/RtsStartup.c ===================================== @@ -192,9 +192,9 @@ static void initBuiltinGcRoots(void) getStablePtr((StgPtr)stackOverflow_closure); getStablePtr((StgPtr)heapOverflow_closure); getStablePtr((StgPtr)unpackCString_closure); - getStablePtr((StgPtr)blockedIndefinitelyOnMVar_closure); - getStablePtr((StgPtr)nonTermination_closure); - getStablePtr((StgPtr)blockedIndefinitelyOnSTM_closure); + getStablePtr((StgPtr)blockedIndefinitelyOnMVarError_closure); + getStablePtr((StgPtr)nonTerminationError_closure); + getStablePtr((StgPtr)blockedIndefinitelyOnSTMError_closure); getStablePtr((StgPtr)allocationLimitExceeded_closure); getStablePtr((StgPtr)cannotCompactFunction_closure); getStablePtr((StgPtr)cannotCompactPinned_closure); ===================================== rts/Schedule.c ===================================== @@ -3309,16 +3309,16 @@ resurrectThreads (StgTSO *threads) case BlockedOnMVar: case BlockedOnMVarRead: /* Called by GC - sched_mutex lock is currently held. */ - throwToSingleThreaded(cap, tso, - (StgClosure *)blockedIndefinitelyOnMVar_closure); + scheduleRaiseViaIO(cap, tso, + (StgClosure *)blockedIndefinitelyOnMVarError_closure); break; case BlockedOnBlackHole: - throwToSingleThreaded(cap, tso, - (StgClosure *)nonTermination_closure); + scheduleRaiseViaIO(cap, tso, + (StgClosure *)nonTerminationError_closure); break; case BlockedOnSTM: - throwToSingleThreaded(cap, tso, - (StgClosure *)blockedIndefinitelyOnSTM_closure); + scheduleRaiseViaIO(cap, tso, + (StgClosure *)blockedIndefinitelyOnSTMError_closure); break; case NotBlocked: /* This might happen if the thread was blocked on a black hole ===================================== rts/include/rts/RtsToHsIface.h ===================================== @@ -20,12 +20,12 @@ typedef struct { StgClosure *stackOverflow_closure; // GHC.Internal.IO.Exception.stackOverflow_closure StgClosure *heapOverflow_closure; // GHC.Internal.IO.Exception.heapOverflow_closure StgClosure *allocationLimitExceeded_closure; // GHC.Internal.IO.Exception.allocationLimitExceeded_closure - StgClosure *blockedIndefinitelyOnMVar_closure; // GHC.Internal.IO.Exception.blockedIndefinitelyOnMVar_closure - StgClosure *blockedIndefinitelyOnSTM_closure; // GHC.Internal.IO.Exception.blockedIndefinitelyOnSTM_closure + StgClosure *blockedIndefinitelyOnMVarError_closure; // GHC.Internal.IO.Exception.blockedIndefinitelyOnMVarError_closure + StgClosure *blockedIndefinitelyOnSTMError_closure; // GHC.Internal.IO.Exception.blockedIndefinitelyOnSTMError_closure StgClosure *cannotCompactFunction_closure; // GHC.Internal.IO.Exception.cannotCompactFunction_closure StgClosure *cannotCompactPinned_closure; // GHC.Internal.IO.Exception.cannotCompactPinned_closure StgClosure *cannotCompactMutable_closure; // GHC.Internal.IO.Exception.cannotCompactMutable_closure - StgClosure *nonTermination_closure; // GHC.Internal.Control.Exception.Base.nonTermination_closure + StgClosure *nonTerminationError_closure; // GHC.Internal.Control.Exception.Base.nonTerminationError_closure StgClosure *nestedAtomically_closure; // GHC.Internal.Control.Exception.Base.nestedAtomically_closure StgClosure *noMatchingContinuationPrompt_closure; // GHC.Internal.Control.Exception.Base.noMatchingContinuationPrompt_closure StgClosure *blockedOnBadFD_closure; // GHC.Internal.Event.Thread.blockedOnBadFD_closure ===================================== testsuite/tests/rts/LoopBacktrace.stderr ===================================== @@ -3,19 +3,19 @@ LoopBacktrace: Uncaught exception ghc-internal:GHC.Internal.Control.Exception.Ba <<loop>> IPE backtrace: - Cmm$rts/StgStartup.cmm. (:) - Cmm$rts/Exception.cmm. (:) - GHC.Internal.Base.thenIO (libraries/ghc-internal/src/GHC/Internal/Base.hs:2336:1-72) - GHC.Internal.IO.Handle.Text. (:) - GHC.Internal.Show. (:) - Main.x (LoopBacktrace.hs:6:1-9) - Cmm$rts/Updates.cmm. (:) - GHC.Num.Integer. (:) - Cmm$rts/HeapStackCheck.cmm. (:) - GHC.Internal.IO.throwIO (libraries/ghc-internal/src/GHC/Internal/IO.hs:285:36) - GHC.Internal.Exception.bindIO (libraries/ghc-internal/src/GHC/Internal/Base.hs:2333:1-76) - GHC.Internal.Exception.Backtrace.bindIO (libraries/ghc-internal/src/GHC/Internal/Base.hs:2333:1-76) - GHC.Internal.Exception.Backtrace.$ (libraries/ghc-internal/src/GHC/Internal/Base.hs:2267:1-9) + GHC.Internal.Exception.Backtrace.collectBacktraces' (libraries/ghc-internal/src/GHC/Internal/Exception/Backtrace.hs:(179,1)-(202,25)) + GHC.Internal.Exception.Backtrace.collectBacktraces (libraries/ghc-internal/src/GHC/Internal/Exception/Backtrace.hs:174:39-56) + GHC.Internal.Exception.toExceptionWithBacktrace (libraries/ghc-internal/src/GHC/Internal/Exception.hs:(179,26)-(181,53)) + GHC.Internal.IO.throwIO (libraries/ghc-internal/src/GHC/Internal/IO.hs:293:36) + Cmm$rts/HeapStackCheck.cmm. (:) + GHC.Internal.Bignum.Integer.integerAdd (libraries/ghc-internal/src/GHC/Internal/Bignum/Integer.hs:(547,1)-(571,52)) + Cmm$rts/Updates.cmm. (:) + Main.x (LoopBacktrace.hs:6:1-9) + GHC.Internal.Show.show (libraries/ghc-internal/src/GHC/Internal/Show.hs:497:10-21) + GHC.Internal.IO.Handle.Text.hPutStr' (libraries/ghc-internal/src/GHC/Internal/IO/Handle/Text.hs:667:29-37) + GHC.Internal.Base.thenIO (libraries/ghc-internal/src/GHC/Internal/Base.hs:2337:1-72) + Cmm$rts/Exception.cmm. (:) + Cmm$rts/StgStartup.cmm. (:) HasCallStack backtrace: - throwIO, called at libraries/ghc-internal/src/GHC/Internal/Control/Exception/Base.hs:446:23 in ghc-internal:GHC.Internal.Control.Exception.Base + throwIO, called at libraries/ghc-internal/src/GHC/Internal/Control/Exception/Base.hs:452:23 in ghc-internal:GHC.Internal.Control.Exception.Base ===================================== testsuite/tests/rts/MVarDeadlockBacktrace.hs ===================================== @@ -0,0 +1,13 @@ +{-# OPTIONS_GHC -finfo-table-map #-} + +-- | Check that a @BlockedIndefinitelyOnMVar@ deadlock exception carries a +-- backtrace mentioning the blocking site in this module. +import Control.Concurrent.MVar +import GHC.Exception.Backtrace.Experimental + +main :: IO () +main = do + setBacktraceMechanismState IPEBacktrace True + mv <- newEmptyMVar :: IO (MVar ()) + x <- takeMVar mv + print x ===================================== testsuite/tests/rts/MVarDeadlockBacktrace.stderr ===================================== @@ -0,0 +1,2 @@ +MVarDeadlockBacktrace: Uncaught exception ghc-internal:GHC.Internal.IO.Exception.BlockedIndefinitelyOnMVar: + Main.main (MVarDeadlockBacktrace.hs:16:3-36) ===================================== testsuite/tests/rts/STMDeadlockBacktrace.hs ===================================== @@ -0,0 +1,12 @@ +{-# OPTIONS_GHC -finfo-table-map #-} + +-- | Check that a @BlockedIndefinitelyOnSTM@ deadlock exception carries a +-- backtrace mentioning the blocking site in this module. +import GHC.Conc (atomically, retry) +import GHC.Exception.Backtrace.Experimental + +main :: IO () +main = do + setBacktraceMechanismState IPEBacktrace True + x <- atomically retry :: IO () + print x ===================================== testsuite/tests/rts/STMDeadlockBacktrace.stderr ===================================== @@ -0,0 +1,2 @@ +STMDeadlockBacktrace: Uncaught exception ghc-internal:GHC.Internal.IO.Exception.BlockedIndefinitelyOnSTM: + Main.main (STMDeadlockBacktrace.hs:16:3-32) ===================================== testsuite/tests/rts/T2783.stderr ===================================== @@ -1,3 +1,7 @@ T2783: Uncaught exception ghc-internal:GHC.Internal.Control.Exception.Base.NonTermination: <<loop>> + +HasCallStack backtrace: + throwIO, called at libraries/ghc-internal/src/GHC/Internal/Control/Exception/Base.hs:452:23 in ghc-internal:GHC.Internal.Control.Exception.Base + ===================================== testsuite/tests/rts/all.T ===================================== @@ -689,3 +689,9 @@ test('ClosureTable', test('resizeMutableByteArrayInPlace', [req_cmm, extra_ways(['optasm', 'sanity']), only_ways(['optasm', 'sanity'])], compile_and_run, ['']) test('LoopBacktrace', [exit_code(1)], compile_and_run, ['']) + +deadlock_backtrace_norm = grep_errmsg(r'(Uncaught exception|Main\.)') +test('MVarDeadlockBacktrace', [exit_code(1), only_ways(['normal']), deadlock_backtrace_norm], + compile_and_run, ['-O']) +test('STMDeadlockBacktrace', [exit_code(1), only_ways(['normal']), deadlock_backtrace_norm], + compile_and_run, ['-O']) View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/82c1e8b92f305584abf59fffad9dad… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/82c1e8b92f305584abf59fffad9dad… You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][wip/loop-backtrace] Throw nontermination exceptions via `throw`
by Ben Gamari (＠bgamari) 22 Jun '26

22 Jun '26

Ben Gamari pushed to branch wip/loop-backtrace at Glasgow Haskell Compiler / GHC Commits: b709d077 by Ben Gamari at 2026-06-21T17:01:08-04:00 Throw nontermination exceptions via `throw` This ensures that the exception that results gets the usual backtrace annotations. This is a first step to #21878. - - - - - 9 changed files: - + changelog.d/builtin-exception-backtraces - libraries/ghc-internal/include/RtsIfaceSymbols.h - libraries/ghc-internal/src/GHC/Internal/Control/Exception/Base.hs - rts/Prelude.h - rts/RtsStartup.c - rts/Schedule.c - rts/include/rts/RtsToHsIface.h - testsuite/tests/rts/LoopBacktrace.stderr - testsuite/tests/rts/T2783.stderr Changes: ===================================== changelog.d/builtin-exception-backtraces ===================================== @@ -0,0 +1,10 @@ +section: rts +synopsis: Non-termination exceptions now have backtrace annotations +issues: #21878 +mrs: !16158 +description: { + The `NonTermination` exception (manifesting in printed exception output as + `<<loop>>`) now include `Backtrace` `ExceptionAnnotations`, like exceptions + thrown from user-written Haskell. +} + ===================================== libraries/ghc-internal/include/RtsIfaceSymbols.h ===================================== @@ -20,7 +20,7 @@ CLOSURE(GHCziInternalziIOziException, blockedIndefinitelyOnSTM_closure) CLOSURE(GHCziInternalziIOziException, cannotCompactFunction_closure) CLOSURE(GHCziInternalziIOziException, cannotCompactPinned_closure) CLOSURE(GHCziInternalziIOziException, cannotCompactMutable_closure) -CLOSURE(GHCziInternalziControlziExceptionziBase, nonTermination_closure) +CLOSURE(GHCziInternalziControlziExceptionziBase, nonTerminationError_closure) CLOSURE(GHCziInternalziControlziExceptionziBase, nestedAtomically_closure) CLOSURE(GHCziInternalziControlziExceptionziBase, noMatchingContinuationPrompt_closure) #if defined(mingw32_HOST_OS) ===================================== libraries/ghc-internal/src/GHC/Internal/Control/Exception/Base.hs ===================================== @@ -108,7 +108,9 @@ module GHC.Internal.Control.Exception.Base ( impossibleError, impossibleConstraintError, nonExhaustiveGuardsError, patError, noMethodBindingError, typeError, - nonTermination, nestedAtomically, noMatchingContinuationPrompt, + nonTermination, nonTerminationError, + nestedAtomically, + noMatchingContinuationPrompt, ) where import GHC.Internal.Base ( @@ -448,6 +450,9 @@ impossibleConstraintError s = errorWithoutStackTrace (unpackCStringUtf8# s) -- GHC's RTS calls this +nonTerminationError :: IO () +nonTerminationError = throwIO NonTermination + nonTermination :: SomeException nonTermination = toException NonTermination ===================================== rts/Prelude.h ===================================== @@ -58,7 +58,7 @@ extern StgClosure ZCMain_main_closure; #define cannotCompactFunction_closure ghc_hs_iface->cannotCompactFunction_closure #define cannotCompactPinned_closure ghc_hs_iface->cannotCompactPinned_closure #define cannotCompactMutable_closure ghc_hs_iface->cannotCompactMutable_closure -#define nonTermination_closure ghc_hs_iface->nonTermination_closure +#define nonTerminationError_closure ghc_hs_iface->nonTerminationError_closure #define nestedAtomically_closure ghc_hs_iface->nestedAtomically_closure #define absentSumFieldError_closure ghc_hs_iface->absentSumFieldError_closure #define underflowException_closure ghc_hs_iface->underflowException_closure ===================================== rts/RtsStartup.c ===================================== @@ -193,7 +193,7 @@ static void initBuiltinGcRoots(void) getStablePtr((StgPtr)heapOverflow_closure); getStablePtr((StgPtr)unpackCString_closure); getStablePtr((StgPtr)blockedIndefinitelyOnMVar_closure); - getStablePtr((StgPtr)nonTermination_closure); + getStablePtr((StgPtr)nonTerminationError_closure); getStablePtr((StgPtr)blockedIndefinitelyOnSTM_closure); getStablePtr((StgPtr)allocationLimitExceeded_closure); getStablePtr((StgPtr)cannotCompactFunction_closure); ===================================== rts/Schedule.c ===================================== @@ -3276,6 +3276,17 @@ findAtomicallyFrameHelper (Capability *cap, StgTSO *tso) } } +static void throwNontermination(Capability *cap, StgTSO *tso) { + StgStack *stack = tso->stackobj; + stack->sp -= 3; + stack->sp[0] = (W_)&stg_enter_info; + stack->sp[1] = (W_)nonTerminationError_closure; + stack->sp[2] = (W_)&stg_ap_v_info; + tso->why_blocked = NotBlocked; + appendToRunQueue(cap,tso); +} + + /* ----------------------------------------------------------------------------- resurrectThreads is called after garbage collection on the list of threads found to be garbage. Each of these threads will be woken @@ -3313,8 +3324,7 @@ resurrectThreads (StgTSO *threads) (StgClosure *)blockedIndefinitelyOnMVar_closure); break; case BlockedOnBlackHole: - throwToSingleThreaded(cap, tso, - (StgClosure *)nonTermination_closure); + throwNontermination(cap, tso); break; case BlockedOnSTM: throwToSingleThreaded(cap, tso, ===================================== rts/include/rts/RtsToHsIface.h ===================================== @@ -25,7 +25,7 @@ typedef struct { StgClosure *cannotCompactFunction_closure; // GHC.Internal.IO.Exception.cannotCompactFunction_closure StgClosure *cannotCompactPinned_closure; // GHC.Internal.IO.Exception.cannotCompactPinned_closure StgClosure *cannotCompactMutable_closure; // GHC.Internal.IO.Exception.cannotCompactMutable_closure - StgClosure *nonTermination_closure; // GHC.Internal.Control.Exception.Base.nonTermination_closure + StgClosure *nonTerminationError_closure; // GHC.Internal.Control.Exception.Base.nonTerminationError_closure StgClosure *nestedAtomically_closure; // GHC.Internal.Control.Exception.Base.nestedAtomically_closure StgClosure *noMatchingContinuationPrompt_closure; // GHC.Internal.Control.Exception.Base.noMatchingContinuationPrompt_closure StgClosure *blockedOnBadFD_closure; // GHC.Internal.Event.Thread.blockedOnBadFD_closure ===================================== testsuite/tests/rts/LoopBacktrace.stderr ===================================== @@ -3,19 +3,19 @@ LoopBacktrace: Uncaught exception ghc-internal:GHC.Internal.Control.Exception.Ba <<loop>> IPE backtrace: - Cmm$rts/StgStartup.cmm. (:) - Cmm$rts/Exception.cmm. (:) - GHC.Internal.Base.thenIO (libraries/ghc-internal/src/GHC/Internal/Base.hs:2336:1-72) - GHC.Internal.IO.Handle.Text. (:) - GHC.Internal.Show. (:) - Main.x (LoopBacktrace.hs:6:1-9) - Cmm$rts/Updates.cmm. (:) - GHC.Num.Integer. (:) - Cmm$rts/HeapStackCheck.cmm. (:) - GHC.Internal.IO.throwIO (libraries/ghc-internal/src/GHC/Internal/IO.hs:285:36) - GHC.Internal.Exception.bindIO (libraries/ghc-internal/src/GHC/Internal/Base.hs:2333:1-76) - GHC.Internal.Exception.Backtrace.bindIO (libraries/ghc-internal/src/GHC/Internal/Base.hs:2333:1-76) - GHC.Internal.Exception.Backtrace.$ (libraries/ghc-internal/src/GHC/Internal/Base.hs:2267:1-9) + GHC.Internal.Exception.Backtrace.collectBacktraces' (libraries/ghc-internal/src/GHC/Internal/Exception/Backtrace.hs:(179,1)-(202,25)) + GHC.Internal.Exception.Backtrace.collectBacktraces (libraries/ghc-internal/src/GHC/Internal/Exception/Backtrace.hs:174:39-56) + GHC.Internal.Exception.toExceptionWithBacktrace (libraries/ghc-internal/src/GHC/Internal/Exception.hs:(179,26)-(181,53)) + GHC.Internal.IO.throwIO (libraries/ghc-internal/src/GHC/Internal/IO.hs:293:36) + Cmm$rts/HeapStackCheck.cmm. (:) + GHC.Internal.Bignum.Integer.integerAdd (libraries/ghc-internal/src/GHC/Internal/Bignum/Integer.hs:(547,1)-(571,52)) + Cmm$rts/Updates.cmm. (:) + Main.x (LoopBacktrace.hs:6:1-9) + GHC.Internal.Show.show (libraries/ghc-internal/src/GHC/Internal/Show.hs:497:10-21) + GHC.Internal.IO.Handle.Text.hPutStr' (libraries/ghc-internal/src/GHC/Internal/IO/Handle/Text.hs:667:29-37) + GHC.Internal.Base.thenIO (libraries/ghc-internal/src/GHC/Internal/Base.hs:2337:1-72) + Cmm$rts/Exception.cmm. (:) + Cmm$rts/StgStartup.cmm. (:) HasCallStack backtrace: - throwIO, called at libraries/ghc-internal/src/GHC/Internal/Control/Exception/Base.hs:446:23 in ghc-internal:GHC.Internal.Control.Exception.Base + throwIO, called at libraries/ghc-internal/src/GHC/Internal/Control/Exception/Base.hs:452:23 in ghc-internal:GHC.Internal.Control.Exception.Base ===================================== testsuite/tests/rts/T2783.stderr ===================================== @@ -1,3 +1,7 @@ T2783: Uncaught exception ghc-internal:GHC.Internal.Control.Exception.Base.NonTermination: <<loop>> + +HasCallStack backtrace: + throwIO, called at libraries/ghc-internal/src/GHC/Internal/Control/Exception/Base.hs:452:23 in ghc-internal:GHC.Internal.Control.Exception.Base + View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/b709d07758de0315cfa9022662305b6… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/b709d07758de0315cfa9022662305b6… You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][wip/decode-orig-update-frames] ghc-heap: Expose OrigThunkInfo frames
by Ben Gamari (＠bgamari) 22 Jun '26

22 Jun '26

Ben Gamari pushed to branch wip/decode-orig-update-frames at Glasgow Haskell Compiler / GHC Commits: 34df124f by Ben Gamari at 2026-06-21T16:56:59-04:00 ghc-heap: Expose OrigThunkInfo frames Introduce a new constructor to StgStackFrame which exposes orig_update_frames, allowing better backtraces when this feature is enabled. - - - - - 4 changed files: - + changelog.d/T24812 - libraries/ghc-internal/cbits/Stack.cmm - libraries/ghc-internal/src/GHC/Internal/Heap/Closures.hs - libraries/ghc-internal/src/GHC/Internal/Stack/Decode.hs Changes: ===================================== changelog.d/T24812 ===================================== @@ -0,0 +1,7 @@ +section: ghc-heap +issues: #24812 +mrs: !16228 +synopsis: + Introduce a `OrigThunkInfo` frame type in `StackFrame`, exposing frames + produced by `-forig-thunk-info`. + ===================================== libraries/ghc-internal/cbits/Stack.cmm ===================================== @@ -3,6 +3,10 @@ #include "Cmm.h" +#if !defined(UnregisterisedCompiler) +import CLOSURE stg_orig_thunk_info_frame_info; +#endif + // StgStack_marking was not available in the Stage0 compiler at the time of // writing. Because, it has been added to derivedConstants when Stack.cmm was // developed. @@ -168,6 +172,18 @@ getStackInfoTableAddrzh(P_ stack) { return (info); } +// (StgInfoTable*) getOrigThunkInfoPtrzh(StgStack* stack, StgWord offsetWords) +getOrigThunkInfoPtrzh(P_ stack, W_ offsetWords) { + P_ p; + p = StgStack_sp(stack) + WDS(offsetWords); + ASSERT(LOOKS_LIKE_CLOSURE_PTR(p)); + if (%INFO_PTR(UNTAG(p)) == stg_orig_thunk_info_frame_info) { + return (StgOrigThunkInfoFrame_info_ptr(UNTAG(p))); + } else { + return (NULL); + } +} + // (StgClosure*) getStackClosurezh(StgStack* stack, StgWord offsetWords) getStackClosurezh(P_ stack, W_ offsetWords) { P_ ptr; ===================================== libraries/ghc-internal/src/GHC/Internal/Heap/Closures.hs ===================================== @@ -568,6 +568,17 @@ data GenStackFrame b = , stack_payload :: ![GenStackField b] } + -- | An @stg_orig_thunk_info_frame@ pushed by @-forig-thunk-info@. It records + -- the original info table of the thunk being updated (in 'orig_info_tbl'), + -- which is otherwise lost when the thunk is blackholed. + -- See @Note [Original thunk info table frames]@ in "GHC.StgToCmm.Bind". + | OrigThunkInfo + { info_tbl :: !StgInfoTable + -- ^ the frame's own (RTS) info table + , orig_info_tbl :: !(Ptr StgInfoTable) + -- ^ the original info table of the thunk being updated + } + | RetFun { info_tbl :: !StgInfoTable , retFunSize :: !Word ===================================== libraries/ghc-internal/src/GHC/Internal/Stack/Decode.hs ===================================== @@ -192,6 +192,16 @@ foreign import prim "getInfoTableAddrszh" getInfoTableAddrs# :: StackSnapshot# - foreign import prim "getStackInfoTableAddrzh" getStackInfoTableAddr# :: StackSnapshot# -> Addr# +foreign import prim "getOrigThunkInfoPtrzh" getOrigThunkInfoPtr# :: StackSnapshot# -> Word# -> Addr# + +-- | @'Just' itbl@ if the frame at the given offset is an +-- @stg_orig_thunk_info_frame@ (where @itbl@ is the recorded original thunk +-- info table), otherwise 'Nothing'. +origThunkInfoFrame :: StackSnapshot# -> WordOffset -> Maybe (Ptr StgInfoTable) +origThunkInfoFrame stackSnapshot# index = + let p = Ptr (getOrigThunkInfoPtr# stackSnapshot# (wordOffsetToWord# index)) + in if p == nullPtr then Nothing else Just p + -- | Get the 'StgInfoTable' of the stack frame. -- Additionally, provides 'InfoProv' for the 'StgInfoTable' if there is any. getInfoTableOnStack :: StackSnapshot# -> WordOffset -> IO (StgInfoTable, Maybe InfoProv) @@ -380,6 +390,15 @@ unpackStackFrameTo (StackSnapshot stackSnapshot#, index) unpackUnderflowFrame fi bco = bco', bcoArgs = bcoArgs' } + RET_SMALL + | Just orig_itbl <- origThunkInfoFrame stackSnapshot# index -> do + orig_info_prov <- lookupIPE (castPtr orig_itbl) + finaliseStackFrame + OrigThunkInfo + { info_tbl = info, + orig_info_tbl = orig_itbl + } + orig_info_prov RET_SMALL -> let payload' = decodeSmallBitmap getSmallBitmap# stackSnapshot# index offsetStgClosurePayload in View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/34df124f2b8bc16ed2c61fb61634c68… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/34df124f2b8bc16ed2c61fb61634c68… You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][wip/sol/reexported-error-message] Reference correct package in error messages for reexported modules
by Simon Hengel (＠sol) 22 Jun '26

22 Jun '26

Simon Hengel pushed to branch wip/sol/reexported-error-message at Glasgow Haskell Compiler / GHC Commits: 26cc1e97 by Simon Hengel at 2026-06-22T03:47:11+07:00 Reference correct package in error messages for reexported modules (fixes #27417) - - - - - 11 changed files: - + changelog.d/reexported-module-errors - compiler/GHC/Iface/Errors.hs - compiler/GHC/Iface/Errors/Ppr.hs - compiler/GHC/Iface/Errors/Types.hs - compiler/GHC/Unit/Finder.hs - compiler/GHC/Unit/Finder/Types.hs - compiler/GHC/Unit/State.hs - ghc/GHCi/UI/Exception.hs - + testsuite/tests/package/ImportReexport.hs - + testsuite/tests/package/ImportReexport.stderr - testsuite/tests/package/all.T Changes: ===================================== changelog.d/reexported-module-errors ===================================== @@ -0,0 +1,4 @@ +section: compiler +synopsis: Reference the correct package in error messages when trying to import a reexported module from a hidden package. +issues: #27417 +mrs: !16229 ===================================== compiler/GHC/Iface/Errors.hs ===================================== @@ -128,7 +128,7 @@ cantFindErr unit_env profile mod_name find_result | otherwise -> GenericMissing - (map ((\uid -> (uid, lookupUnit (ue_homeUnitState unit_env) uid))) pkg_hiddens) + pkg_hiddens mod_hiddens unusables files _ -> panic "cantFindErr" ===================================== compiler/GHC/Iface/Errors/Ppr.hs ===================================== @@ -261,13 +261,13 @@ cantFindErrorX pkg_hidden_hint may_show_locations mod_or_interface (CantFindInst .ppr.mkUnit) res ++ if f then [text "a package flag"] else [] ) - pkg_hidden :: (Unit, Maybe UnitInfo) -> SDoc - pkg_hidden (uid, uif) = + pkg_hidden :: UnitInfo -> SDoc + pkg_hidden unit = text "It is a member of the hidden package" - <+> quotes (ppr uid) + <+> quotes (ppr $ unitId unit) --FIXME: we don't really want to show the unit id here we should -- show the source package id or installed package id if it's ambiguous - <> dot $$ maybe empty pkg_hidden_hint uif + <> dot $$ pkg_hidden_hint unit mod_hidden pkg = ===================================== compiler/GHC/Iface/Errors/Types.hs ===================================== @@ -73,7 +73,7 @@ data CantFindInstalledReason | NotAModule | CouldntFindInFiles [FilePath] | GenericMissing - [(Unit, Maybe UnitInfo)] [Unit] + [UnitInfo] [Unit] [UnusableUnit] [FilePath] | MultiplePackages [(Module, ModuleOrigin)] deriving Generic ===================================== compiler/GHC/Unit/Finder.hs ===================================== @@ -510,9 +510,9 @@ findLookupResult fc fopts r = case r of , fr_suggestions = []}) LookupMultiple rs -> return (FoundMultiple rs) - LookupHidden pkg_hiddens mod_hiddens -> + LookupHidden fr_pkgs_hidden mod_hiddens -> return (NotFound{ fr_paths = [], fr_pkg = Nothing - , fr_pkgs_hidden = map (moduleUnit.fst) pkg_hiddens + , fr_pkgs_hidden , fr_mods_hidden = map (moduleUnit.fst) mod_hiddens , fr_unusables = [] , fr_suggestions = [] }) ===================================== compiler/GHC/Unit/Finder/Types.hs ===================================== @@ -70,7 +70,7 @@ data FindResult , fr_mods_hidden :: [Unit] -- ^ Module is in these units, -- but the *module* is hidden - , fr_pkgs_hidden :: [Unit] -- ^ Module is in these units, + , fr_pkgs_hidden :: [UnitInfo] -- ^ Module is in these units, -- but the *unit* is hidden -- | Module is in these units, but it is unusable ===================================== compiler/GHC/Unit/State.hs ===================================== @@ -1905,7 +1905,7 @@ data LookupResult = -- | No modules found, but there were some hidden ones with -- an exact name match. First is due to package hidden, second -- is due to module being hidden - | LookupHidden [(Module, ModuleOrigin)] [(Module, ModuleOrigin)] + | LookupHidden [UnitInfo] [(Module, ModuleOrigin)] -- | No modules found, but there were some unusable ones with -- an exact name match | LookupUnusable [(Module, ModuleOrigin)] @@ -1954,8 +1954,8 @@ lookupModuleWithSuggestions' :: UnitState -> ModuleName -> PkgQual -> LookupResult -lookupModuleWithSuggestions' pkgs mod_map m mb_pn - = case lookupUniqMap mod_map m of +lookupModuleWithSuggestions' pkgs mod_map name mb_pn + = case lookupUniqMap mod_map name of Nothing -> LookupNotFound suggestions Just xs -> case foldl' classify ([],[],[], []) (sortOn fst $ nonDetUniqMapToList xs) of @@ -1969,19 +1969,26 @@ lookupModuleWithSuggestions' pkgs mod_map m mb_pn classify (hidden_pkg, hidden_mod, unusable, exposed) (m, origin0) = let origin = filterOrigin mb_pn (mod_unit m) origin0 x = (m, origin) + + originUnit :: [UnitInfo] -> [UnitInfo] + originUnit + | moduleName m == name, Just pkg <- lookupUnit pkgs (moduleUnit m) = (pkg :) + | otherwise = id + in case origin of ModHidden -> (hidden_pkg, x:hidden_mod, unusable, exposed) ModUnusable _ -> (hidden_pkg, hidden_mod, x:unusable, exposed) - _ | originEmpty origin + ModOrigin _ _ reexports _ + | originEmpty origin -> (hidden_pkg, hidden_mod, unusable, exposed) | originVisible origin -> (hidden_pkg, hidden_mod, unusable, x:exposed) | otherwise - -> (x:hidden_pkg, hidden_mod, unusable, exposed) + -> (reexports ++ originUnit hidden_pkg, hidden_mod, unusable, exposed) - unit_lookup p = lookupUnit pkgs p `orElse` pprPanic "lookupModuleWithSuggestions" (ppr p <+> ppr m) + unit_lookup p = lookupUnit pkgs p `orElse` pprPanic "lookupModuleWithSuggestions" (ppr p <+> ppr name) mod_unit = unit_lookup . moduleUnit -- Filters out origins which are not associated with the given package @@ -2011,7 +2018,7 @@ lookupModuleWithSuggestions' pkgs mod_map m mb_pn , fromPackageFlag = False -- always excluded } - suggestions = fuzzyLookup (moduleNameString m) all_mods + suggestions = fuzzyLookup (moduleNameString name) all_mods all_mods :: [(String, ModuleSuggestion)] -- All modules all_mods = sortBy (comparing fst) $ ===================================== ghc/GHCi/UI/Exception.hs ===================================== @@ -222,11 +222,13 @@ ghciDiagnosticMessage ghc_opts msg = Just (pprWithUnitState us $ cantFindErrorX pkg_hidden_hint may_show_locations module_or_interface cfi) _ -> Nothing where - + may_show_locations :: [String] -> SDoc may_show_locations = mayShowLocations ":set -v" (ifaceShowTriedFiles opts) + pkg_hidden_hint :: UnitInfo -> SDoc pkg_hidden_hint = pkgHiddenHint hidden_msg (ifaceBuildingCabalPackage opts) where + hidden_msg :: UnitInfo -> SDoc hidden_msg pkg = text "You can run" <+> quotes (text ":set -package " <> ppr (unitPackageName pkg)) <+> ===================================== testsuite/tests/package/ImportReexport.hs ===================================== @@ -0,0 +1,2 @@ +module ImportReexport where +import GHC.Types -- reexported by ghc-prim from ghc-internal ===================================== testsuite/tests/package/ImportReexport.stderr ===================================== @@ -0,0 +1,5 @@ +ImportReexport.hs:2:1: error: [GHC-87110] + Could not load module ‘GHC.Types’. + It is a member of the hidden package ‘ghc-prim-0.14.0’. + Use -v to see a list of the files searched for. + ===================================== testsuite/tests/package/all.T ===================================== @@ -13,6 +13,7 @@ test('package04', normal, compile, [incr_containers]) test('package05', normal, compile, [incr_ghc + inc_ghc]) test('package06', normal, compile, [incr_ghc]) test('package06e', normalise_version('ghc'), compile_fail, [incr_ghc]) +test('ImportReexport', normalise_version('ghc'), compile_fail, ['-hide-all-packages -XNoImplicitPrelude']) test('package07e', normalise_version('ghc'), compile_fail, [incr_ghc + inc_ghc + hide_ghc]) test('package08e', normalise_version('ghc'), compile_fail, [incr_ghc + hide_ghc]) test('package09e', normal, compile_fail, ['-package "containers (Data.Map as M, Data.Set as M)"']) View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/26cc1e979319c1827c2418af2819a5f… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/26cc1e979319c1827c2418af2819a5f… You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][wip/az/exactprint-annotation-rationalisation] 9 commits: EPA: remove LocatedL / SrcSpanAnnL and LocatedLI / SrcSpanAnnLI
by Alan Zimmerman (＠alanz) 22 Jun '26

22 Jun '26

Alan Zimmerman pushed to branch wip/az/exactprint-annotation-rationalisation at Glasgow Haskell Compiler / GHC Commits: 2fc3fe40 by Alan Zimmerman at 2026-06-21T20:08:52+01:00 EPA: remove LocatedL / SrcSpanAnnL and LocatedLI / SrcSpanAnnLI This is part of a refactor towards only having LocatedA / SrcSpanAnnA It removes the stated items, but has to add back one for BooleanFormula, LocatedBF / SrcSpanAnnBF This commit also use the HsConDetails RecCon extension point to capture the braces in a record constructor - - - - - 2f274bbd by Alan Zimmerman at 2026-06-21T20:08:52+01:00 EPA: Remove LocatedC / SrcSpanAnnC Used for contexts - - - - - 880fa55a by Alan Zimmerman at 2026-06-21T20:08:52+01:00 EPA: Harmonise HsQual/HsQualTy TTG extension annotations - - - - - 87e0d0e2 by Alan Zimmerman at 2026-06-21T20:08:52+01:00 EPA Remove LocatedLC / LocatedLS LocatedLC/LocatedLS were unused - - - - - 5edf983d by Alan Zimmerman at 2026-06-21T21:41:38+01:00 EPA: Remove LocatedLW from LStmtLR - - - - - 41d493ec by Alan Zimmerman at 2026-06-21T21:41:38+01:00 EPA: Remove LocatedLW from MatchGroup This is the last usage of LocatedLW / SrcSpanAnnLW - - - - - 5cf22470 by Alan Zimmerman at 2026-06-21T21:41:38+01:00 EPA: Move the 'where' annotation for PatSynBind This allows us to move it out of the MatchGroup exact print annotation too - - - - - 5eee5d98 by Alan Zimmerman at 2026-06-21T21:41:38+01:00 EPA: Replace AnnListItem with simply [TrailingAnn] Remove the unnecessary wrapper around a single field. - - - - - 27747cee by Alan Zimmerman at 2026-06-21T21:41:38+01:00 Keep binds and sigs together in HsValBindsLR TBD - - - - - 95 changed files: - compiler/GHC/Data/BooleanFormula.hs - compiler/GHC/Hs.hs - compiler/GHC/Hs/Binds.hs - compiler/GHC/Hs/Decls.hs - compiler/GHC/Hs/Dump.hs - compiler/GHC/Hs/Expr.hs - compiler/GHC/Hs/ImpExp.hs - compiler/GHC/Hs/Instances.hs - compiler/GHC/Hs/Pat.hs - compiler/GHC/Hs/Stats.hs - compiler/GHC/Hs/Type.hs - compiler/GHC/Hs/Utils.hs - compiler/GHC/HsToCore/Pmc/Desugar.hs - compiler/GHC/HsToCore/Quote.hs - compiler/GHC/HsToCore/Ticks.hs - compiler/GHC/Iface/Ext/Ast.hs - compiler/GHC/Parser.y - compiler/GHC/Parser/Annotation.hs - compiler/GHC/Parser/PostProcess.hs - compiler/GHC/Parser/PostProcess/Haddock.hs - compiler/GHC/Parser/Types.hs - compiler/GHC/Rename/Bind.hs - compiler/GHC/Rename/Expr.hs - compiler/GHC/Rename/HsType.hs - compiler/GHC/Rename/Module.hs - compiler/GHC/Rename/Names.hs - compiler/GHC/Rename/Pat.hs - compiler/GHC/Rename/Utils.hs - compiler/GHC/Runtime/Eval.hs - compiler/GHC/Tc/Deriv.hs - compiler/GHC/Tc/Deriv/Generate.hs - compiler/GHC/Tc/Gen/App.hs - compiler/GHC/Tc/Gen/Arrow.hs - compiler/GHC/Tc/Gen/Do.hs - compiler/GHC/Tc/Gen/Export.hs - compiler/GHC/Tc/Gen/Expr.hs - compiler/GHC/Tc/Gen/Head.hs - compiler/GHC/Tc/Gen/HsType.hs - compiler/GHC/Tc/Gen/Match.hs - compiler/GHC/Tc/Gen/Sig.hs - compiler/GHC/Tc/Module.hs - compiler/GHC/Tc/TyCl.hs - compiler/GHC/Tc/TyCl/PatSyn.hs - compiler/GHC/Tc/TyCl/Utils.hs - compiler/GHC/Tc/Utils/Backpack.hs - compiler/GHC/ThToHs.hs - compiler/Language/Haskell/Syntax.hs - compiler/Language/Haskell/Syntax/Binds.hs - compiler/Language/Haskell/Syntax/Expr.hs - compiler/Language/Haskell/Syntax/Extension.hs - compiler/Language/Haskell/Syntax/ImpExp.hs - compiler/Language/Haskell/Syntax/Type.hs - ghc/GHCi/UI.hs - testsuite/tests/ghc-api/T25121_status.stdout - testsuite/tests/ghc-api/exactprint/T22919.stderr - testsuite/tests/ghc-api/exactprint/Test20239.stderr - testsuite/tests/ghc-api/exactprint/ZeroWidthSemi.stderr - testsuite/tests/haddock/should_compile_flag_haddock/T17544.stderr - testsuite/tests/haddock/should_compile_flag_haddock/T17544_kw.stderr - testsuite/tests/haddock/should_compile_flag_haddock/T24221.stderr - testsuite/tests/module/mod185.stderr - testsuite/tests/parser/should_compile/DumpParsedAst.stderr - testsuite/tests/parser/should_compile/DumpParsedAstComments.stderr - testsuite/tests/parser/should_compile/DumpRenamedAst.stderr - testsuite/tests/parser/should_compile/DumpSemis.stderr - testsuite/tests/parser/should_compile/DumpTypecheckedAst.stderr - testsuite/tests/parser/should_compile/KindSigs.stderr - testsuite/tests/parser/should_compile/T14189.stderr - testsuite/tests/parser/should_compile/T15279.stderr - testsuite/tests/parser/should_compile/T15323.stderr - testsuite/tests/parser/should_compile/T20452.stderr - testsuite/tests/parser/should_compile/T20718.stderr - testsuite/tests/parser/should_compile/T20718b.stderr - testsuite/tests/parser/should_compile/T20846.stderr - testsuite/tests/parser/should_compile/T23315/T23315.stderr - testsuite/tests/parser/should_compile/all.T - testsuite/tests/printer/AnnotationNoListTuplePuns.stdout - testsuite/tests/printer/T18791.stderr - testsuite/tests/printer/Test10309.hs - testsuite/tests/printer/Test20297.stdout - testsuite/tests/printer/Test24533.stdout - testsuite/tests/typecheck/should_compile/T15242.stderr - testsuite/tests/typecheck/should_compile/all.T - utils/check-exact/ExactPrint.hs - utils/check-exact/Main.hs - utils/check-exact/Transform.hs - utils/check-exact/Utils.hs - utils/haddock/haddock-api/src/Haddock/Backends/LaTeX.hs - utils/haddock/haddock-api/src/Haddock/Backends/Xhtml/Decl.hs - utils/haddock/haddock-api/src/Haddock/Convert.hs - utils/haddock/haddock-api/src/Haddock/GhcUtils.hs - utils/haddock/haddock-api/src/Haddock/Interface/Create.hs - utils/haddock/haddock-api/src/Haddock/Interface/Rename.hs - utils/haddock/haddock-api/src/Haddock/Interface/RenameType.hs - utils/haddock/haddock-api/src/Haddock/Types.hs The diff was not included because it is too large. View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/fb1f5a2da19d4ba9c25db8b4ad2238… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/fb1f5a2da19d4ba9c25db8b4ad2238… You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][wip/az/epa-tidy-locatedxxx-1] EPA: remove LocatedL / SrcSpanAnnL and LocatedLI / SrcSpanAnnLI
by Alan Zimmerman (＠alanz) 22 Jun '26

22 Jun '26

Alan Zimmerman pushed to branch wip/az/epa-tidy-locatedxxx-1 at Glasgow Haskell Compiler / GHC Commits: 2fc3fe40 by Alan Zimmerman at 2026-06-21T20:08:52+01:00 EPA: remove LocatedL / SrcSpanAnnL and LocatedLI / SrcSpanAnnLI This is part of a refactor towards only having LocatedA / SrcSpanAnnA It removes the stated items, but has to add back one for BooleanFormula, LocatedBF / SrcSpanAnnBF This commit also use the HsConDetails RecCon extension point to capture the braces in a record constructor - - - - - 62 changed files: - compiler/GHC/Data/BooleanFormula.hs - compiler/GHC/Hs.hs - compiler/GHC/Hs/Binds.hs - compiler/GHC/Hs/Decls.hs - compiler/GHC/Hs/Dump.hs - compiler/GHC/Hs/Expr.hs - compiler/GHC/Hs/ImpExp.hs - compiler/GHC/Hs/Pat.hs - compiler/GHC/Hs/Stats.hs - compiler/GHC/Hs/Type.hs - compiler/GHC/Hs/Utils.hs - compiler/GHC/HsToCore/Pmc/Desugar.hs - compiler/GHC/HsToCore/Quote.hs - compiler/GHC/Iface/Ext/Ast.hs - compiler/GHC/Parser.y - compiler/GHC/Parser/Annotation.hs - compiler/GHC/Parser/PostProcess.hs - compiler/GHC/Parser/PostProcess/Haddock.hs - compiler/GHC/Rename/Expr.hs - compiler/GHC/Rename/Module.hs - compiler/GHC/Rename/Names.hs - compiler/GHC/Rename/Pat.hs - compiler/GHC/Tc/Deriv/Generate.hs - compiler/GHC/Tc/Gen/Export.hs - compiler/GHC/Tc/Module.hs - compiler/GHC/Tc/TyCl.hs - compiler/GHC/Tc/TyCl/Utils.hs - compiler/GHC/Tc/Utils/Backpack.hs - compiler/GHC/ThToHs.hs - compiler/Language/Haskell/Syntax.hs - compiler/Language/Haskell/Syntax/ImpExp.hs - ghc/GHCi/UI.hs - testsuite/tests/ghc-api/exactprint/T22919.stderr - testsuite/tests/ghc-api/exactprint/Test20239.stderr - testsuite/tests/ghc-api/exactprint/ZeroWidthSemi.stderr - testsuite/tests/haddock/should_compile_flag_haddock/T17544.stderr - testsuite/tests/haddock/should_compile_flag_haddock/T17544_kw.stderr - testsuite/tests/haddock/should_compile_flag_haddock/T24221.stderr - testsuite/tests/module/mod185.stderr - testsuite/tests/parser/should_compile/DumpParsedAst.stderr - testsuite/tests/parser/should_compile/DumpParsedAstComments.stderr - testsuite/tests/parser/should_compile/DumpRenamedAst.stderr - testsuite/tests/parser/should_compile/DumpSemis.stderr - testsuite/tests/parser/should_compile/KindSigs.stderr - testsuite/tests/parser/should_compile/T14189.stderr - testsuite/tests/parser/should_compile/T15323.stderr - testsuite/tests/parser/should_compile/T20452.stderr - testsuite/tests/parser/should_compile/T20718.stderr - testsuite/tests/parser/should_compile/T20718b.stderr - testsuite/tests/parser/should_compile/T20846.stderr - testsuite/tests/parser/should_compile/T23315/T23315.stderr - testsuite/tests/printer/AnnotationNoListTuplePuns.stdout - testsuite/tests/printer/T18791.stderr - testsuite/tests/printer/Test10309.hs - testsuite/tests/printer/Test20297.stdout - testsuite/tests/printer/Test24533.stdout - utils/check-exact/ExactPrint.hs - utils/check-exact/Main.hs - utils/check-exact/Utils.hs - utils/haddock/haddock-api/src/Haddock/Convert.hs - utils/haddock/haddock-api/src/Haddock/Interface/Rename.hs - utils/haddock/haddock-api/src/Haddock/Types.hs The diff was not included because it is too large. View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/2fc3fe408286c22e575fca2a2db3e89… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/2fc3fe408286c22e575fca2a2db3e89… You're receiving this email because of your account on gitlab.haskell.org.

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