January 2026 - ghc-commits

[Git][ghc/ghc] Pushed new branch wip/T26722
by Simon Peyton Jones (＠simonpj) 06 Jan '26

06 Jan '26

Simon Peyton Jones pushed new branch wip/T26722 at Glasgow Haskell Compiler / GHC -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/tree/wip/T26722 You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][wip/fix-clang64-split-sections] 9 commits: Improved fundeps for closed type families
by Cheng Shao (＠TerrorJack) 06 Jan '26

06 Jan '26

Cheng Shao pushed to branch wip/fix-clang64-split-sections at Glasgow Haskell Compiler / GHC Commits: 0b7df6db by Simon Peyton Jones at 2026-01-06T09:32:23-05:00 Improved fundeps for closed type families The big payload of this commit is to execute the plan suggested in #23162, by improving the way that we generate functional dependencies for closed type families. It is all described in Note [Exploiting closed type families] Most of the changes are in GHC.Tc.Solver.FunDeps Other small changes * GHC.Tc.Solver.bumpReductionDepth. This function brings together the code that * Bumps the depth * Checks for overflow Previously the two were separated, sometimes quite widely. * GHC.Core.Unify.niFixSubst: minor improvement, removing an unnecessary itraetion in the base case. * GHC.Core.Unify: no need to pass an InScopeSet to tcUnifyTysForInjectivity. It can calculate one for itself; and it is never inspected anyway so it's free to do so. * GHC.Tc.Errors.Ppr: slight impovement to the error message for reduction-stack overflow, when a constraint (rather than a type) is involved. * GHC.Tc.Solver.Monad.wrapUnifier: small change to the API - - - - - fde8bd88 by Simon Peyton Jones at 2026-01-06T09:32:23-05:00 Add missing (KK4) to kick-out criteria There was a missing case in kick-out that meant we could fail to solve an eminently-solvable constraint. See the new notes about (KK4) - - - - - 00082844 by Simon Peyton Jones at 2026-01-06T09:32:23-05:00 Some small refactorings of error reporting in the typechecker This is just a tidy-up commit. * Add ei_insoluble to ErrorItem, to cache insolubility. Small tidy-up. * Remove `is_ip` and `mkIPErr` from GHC.Tc.Errors; instead enhance mkDictErr to handle implicit parameters. Small refactor. - - - - - fe4cb252 by Simon Peyton Jones at 2026-01-06T09:32:24-05:00 Improve recording of insolubility for fundeps This commit addresses #22652, by recording when the fundeps for a constraint are definitely insoluble. That in turn improves the perspicacity of the pattern-match overlap checker. See Note [Insoluble fundeps] - - - - - df0ffaa5 by Simon Peyton Jones at 2026-01-06T09:32:24-05:00 Fix a buglet in niFixSubst The MR of which this is part failed an assertion check extendTvSubst because we extended the TvSubst with a CoVar. Boo. This tiny patch fixes it, and adds the regression test from #13882 that showed it up. - - - - - 3d6aba77 by konsumlamm at 2026-01-06T09:33:16-05:00 Fix changelog formatting - - - - - 76b190c5 by Cheng Shao at 2026-01-06T17:30:21+01:00 compiler: change sectionProtection to take SectionType argument This commit changes `sectionProtection` to only take `SectionType` argument instead of whole `Section`, since it doesn't need the Cmm section content anyway, and it can then be called in parts of NCG where we only have a `SectionType` in scope. - - - - - b5c1becd by Cheng Shao at 2026-01-06T17:30:21+01:00 compiler: change isInitOrFiniSection to take SectionType argument This commit changes `isInitOrFiniSection` to only take `SectionType` argument instead of whole `Section`, since it doesn't need the Cmm section content anyway, and it can then be called in parts of NCG where we only have a `SectionType` in scope. Also marks it as exported. - - - - - b70bcb0e by Cheng Shao at 2026-01-06T17:30:32+01:00 compiler: fix split sections on windows This patch fixes split sections on windows by emitting the right COMDAT section header in NCG, see added comment for more explanation. Fix #26696 #26494. ------------------------- Metric Decrease: T9675 size_hello_artifact size_hello_artifact_gzip size_hello_unicode size_hello_unicode_gzip Metric Increase: T13035 ------------------------- Co-authored-by: Codex <codex(a)openai.com> - - - - - 78 changed files: - compiler/GHC/Cmm.hs - compiler/GHC/Cmm/InitFini.hs - compiler/GHC/CmmToAsm/AArch64/Ppr.hs - compiler/GHC/CmmToAsm/Ppr.hs - compiler/GHC/CmmToAsm/Wasm/FromCmm.hs - compiler/GHC/CmmToAsm/X86/Ppr.hs - compiler/GHC/CmmToC.hs - compiler/GHC/CmmToLlvm/Data.hs - compiler/GHC/Core/FamInstEnv.hs - compiler/GHC/Core/TyCo/Subst.hs - compiler/GHC/Core/TyCon.hs - compiler/GHC/Core/Unify.hs - compiler/GHC/HsToCore/Monad.hs - compiler/GHC/Tc/Errors.hs - compiler/GHC/Tc/Errors/Ppr.hs - compiler/GHC/Tc/Errors/Types.hs - compiler/GHC/Tc/Gen/Splice.hs - compiler/GHC/Tc/Solver.hs - compiler/GHC/Tc/Solver/Default.hs - compiler/GHC/Tc/Solver/Dict.hs - compiler/GHC/Tc/Solver/Equality.hs - compiler/GHC/Tc/Solver/FunDeps.hs - compiler/GHC/Tc/Solver/InertSet.hs - compiler/GHC/Tc/Solver/Monad.hs - compiler/GHC/Tc/Solver/Rewrite.hs - compiler/GHC/Tc/Types/Constraint.hs - compiler/GHC/Tc/Types/CtLoc.hs - compiler/GHC/Tc/Utils/Monad.hs - compiler/GHC/Tc/Utils/Unify.hs - compiler/GHC/Types/TyThing.hs - docs/users_guide/9.16.1-notes.rst - libraries/base/changelog.md - linters/lint-codes/LintCodes/Static.hs - testsuite/tests/indexed-types/should_compile/CEqCanOccursCheck.hs - testsuite/tests/indexed-types/should_fail/T12522a.hs - testsuite/tests/indexed-types/should_fail/T26176.stderr - testsuite/tests/parser/should_fail/RecordDotSyntaxFail10.stderr - testsuite/tests/parser/should_fail/RecordDotSyntaxFail13.stderr - testsuite/tests/parser/should_fail/T20654a.stderr - testsuite/tests/pmcheck/should_compile/T15753c.hs - + testsuite/tests/pmcheck/should_compile/T15753c.stderr - testsuite/tests/pmcheck/should_compile/T15753d.hs - + testsuite/tests/pmcheck/should_compile/T15753d.stderr - + testsuite/tests/pmcheck/should_compile/T22652.hs - + testsuite/tests/pmcheck/should_compile/T22652a.hs - testsuite/tests/pmcheck/should_compile/all.T - + testsuite/tests/polykinds/T13882.hs - testsuite/tests/polykinds/all.T - testsuite/tests/quantified-constraints/T15316A.stderr - testsuite/tests/quantified-constraints/T17267.stderr - testsuite/tests/quantified-constraints/T17267a.stderr - testsuite/tests/quantified-constraints/T17267b.stderr - testsuite/tests/quantified-constraints/T17267c.stderr - testsuite/tests/quantified-constraints/T17267e.stderr - testsuite/tests/quantified-constraints/T17458.stderr - testsuite/tests/typecheck/should_compile/T16188.hs - testsuite/tests/typecheck/should_fail/ContextStack1.stderr - testsuite/tests/typecheck/should_fail/FD3.stderr - testsuite/tests/typecheck/should_fail/FDsFromGivens2.stderr - testsuite/tests/typecheck/should_fail/FunDepOrigin1b.stderr - testsuite/tests/typecheck/should_fail/T13506.stderr - testsuite/tests/typecheck/should_fail/T15767.stderr - testsuite/tests/typecheck/should_fail/T19415.stderr - testsuite/tests/typecheck/should_fail/T19415b.stderr - testsuite/tests/typecheck/should_fail/T22924b.stderr - + testsuite/tests/typecheck/should_fail/T23162b.hs - + testsuite/tests/typecheck/should_fail/T23162b.stderr - + testsuite/tests/typecheck/should_fail/T23162c.hs - + testsuite/tests/typecheck/should_fail/T23162d.hs - testsuite/tests/typecheck/should_fail/T25325.stderr - testsuite/tests/typecheck/should_fail/T5236.stderr - testsuite/tests/typecheck/should_fail/T5246.stderr - testsuite/tests/typecheck/should_fail/T5978.stderr - testsuite/tests/typecheck/should_fail/T9612.stderr - testsuite/tests/typecheck/should_fail/TcCoercibleFail.stderr - testsuite/tests/typecheck/should_fail/all.T - testsuite/tests/typecheck/should_fail/tcfail143.stderr - utils/haddock/haddock-api/src/Haddock/Convert.hs The diff was not included because it is too large. View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/17030d83bcd6a9f9b7e1d758b5efea… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/17030d83bcd6a9f9b7e1d758b5efea… You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][wip/marge_bot_batch_merge_job] 13 commits: Improved fundeps for closed type families
by Marge Bot (＠marge-bot) 06 Jan '26

06 Jan '26

Marge Bot pushed to branch wip/marge_bot_batch_merge_job at Glasgow Haskell Compiler / GHC Commits: 0b7df6db by Simon Peyton Jones at 2026-01-06T09:32:23-05:00 Improved fundeps for closed type families The big payload of this commit is to execute the plan suggested in #23162, by improving the way that we generate functional dependencies for closed type families. It is all described in Note [Exploiting closed type families] Most of the changes are in GHC.Tc.Solver.FunDeps Other small changes * GHC.Tc.Solver.bumpReductionDepth. This function brings together the code that * Bumps the depth * Checks for overflow Previously the two were separated, sometimes quite widely. * GHC.Core.Unify.niFixSubst: minor improvement, removing an unnecessary itraetion in the base case. * GHC.Core.Unify: no need to pass an InScopeSet to tcUnifyTysForInjectivity. It can calculate one for itself; and it is never inspected anyway so it's free to do so. * GHC.Tc.Errors.Ppr: slight impovement to the error message for reduction-stack overflow, when a constraint (rather than a type) is involved. * GHC.Tc.Solver.Monad.wrapUnifier: small change to the API - - - - - fde8bd88 by Simon Peyton Jones at 2026-01-06T09:32:23-05:00 Add missing (KK4) to kick-out criteria There was a missing case in kick-out that meant we could fail to solve an eminently-solvable constraint. See the new notes about (KK4) - - - - - 00082844 by Simon Peyton Jones at 2026-01-06T09:32:23-05:00 Some small refactorings of error reporting in the typechecker This is just a tidy-up commit. * Add ei_insoluble to ErrorItem, to cache insolubility. Small tidy-up. * Remove `is_ip` and `mkIPErr` from GHC.Tc.Errors; instead enhance mkDictErr to handle implicit parameters. Small refactor. - - - - - fe4cb252 by Simon Peyton Jones at 2026-01-06T09:32:24-05:00 Improve recording of insolubility for fundeps This commit addresses #22652, by recording when the fundeps for a constraint are definitely insoluble. That in turn improves the perspicacity of the pattern-match overlap checker. See Note [Insoluble fundeps] - - - - - df0ffaa5 by Simon Peyton Jones at 2026-01-06T09:32:24-05:00 Fix a buglet in niFixSubst The MR of which this is part failed an assertion check extendTvSubst because we extended the TvSubst with a CoVar. Boo. This tiny patch fixes it, and adds the regression test from #13882 that showed it up. - - - - - 3d6aba77 by konsumlamm at 2026-01-06T09:33:16-05:00 Fix changelog formatting - - - - - d30b61cd by Cheng Shao at 2026-01-06T11:07:24-05:00 compiler: add targetHasRTSWays function This commit adds a `targetHasRTSWays` util function in `GHC.Driver.Session` to query if the target RTS has a given Ways (e.g. WayThreaded). - - - - - 199c6c23 by Cheng Shao at 2026-01-06T11:07:24-05:00 compiler: link on-demand external interpreter with threaded RTS This commit makes the compiler link the on-demand external interpreter program with threaded RTS if it is available in the target RTS ways. This is a better default than the previous single-threaded RTS, and it enables the external interpreter to benefit from parallelism when deserializing CreateBCOs messages. - - - - - 5eca37e4 by Cheng Shao at 2026-01-06T11:07:25-05:00 hadrian: link iserv with threaded RTS This commit makes hadrian link iserv with threaded RTS if it's available in the RTS ways. Also cleans up the iserv main C program which can be replaced by the `-fkeep-cafs` link-time option. - - - - - 87af9f99 by Cheng Shao at 2026-01-06T11:07:25-05:00 ghc-internal: remove unused GMP macros This patch removes unused GMP related macros from `ghc-internal`. The in-tree GMP version was hard coded and outdated, but it was not used anywhere anyway. - - - - - 7f8b7773 by Cheng Shao at 2026-01-06T11:07:25-05:00 hadrian: fix in-tree gmp configure error on newer c compilers Building in-tree gmp on newer c compilers that default to c23 fails at configure stage, this patch fixes it, see added comment for explanation. - - - - - 44261b88 by Cheng Shao at 2026-01-06T11:07:26-05:00 compiler: fix LLVM backend pdep/pext handling for i386 target This patch fixes LLVM backend's pdep/pext handling for i386 target, and also removes non-existent 128/256/512 bit hs_pdep/hs_pext callees. See amended note for more explanation. Fixes #26450. Co-authored-by: Codex <codex(a)openai.com> - - - - - b15b1423 by Cheng Shao at 2026-01-06T11:07:26-05:00 ci: remove allow_failure flag for i386 alpine job The LLVM codegen issue for i386 has been fixed, and the i386 alpine job should pass now. This commit removes the allow_failure flag so that other i386 regressions in the future are signaled more timely. - - - - - 84 changed files: - .gitlab/generate-ci/gen_ci.hs - .gitlab/jobs.yaml - compiler/GHC.hs - compiler/GHC/CmmToLlvm/CodeGen.hs - compiler/GHC/Core/FamInstEnv.hs - compiler/GHC/Core/TyCo/Subst.hs - compiler/GHC/Core/TyCon.hs - compiler/GHC/Core/Unify.hs - compiler/GHC/Driver/Session.hs - compiler/GHC/HsToCore/Monad.hs - compiler/GHC/Runtime/Interpreter/C.hs - compiler/GHC/Runtime/Interpreter/Init.hs - compiler/GHC/Tc/Errors.hs - compiler/GHC/Tc/Errors/Ppr.hs - compiler/GHC/Tc/Errors/Types.hs - compiler/GHC/Tc/Gen/Splice.hs - compiler/GHC/Tc/Solver.hs - compiler/GHC/Tc/Solver/Default.hs - compiler/GHC/Tc/Solver/Dict.hs - compiler/GHC/Tc/Solver/Equality.hs - compiler/GHC/Tc/Solver/FunDeps.hs - compiler/GHC/Tc/Solver/InertSet.hs - compiler/GHC/Tc/Solver/Monad.hs - compiler/GHC/Tc/Solver/Rewrite.hs - compiler/GHC/Tc/Types/Constraint.hs - compiler/GHC/Tc/Types/CtLoc.hs - compiler/GHC/Tc/Utils/Monad.hs - compiler/GHC/Tc/Utils/Unify.hs - compiler/GHC/Types/TyThing.hs - docs/users_guide/9.16.1-notes.rst - hadrian/src/Packages.hs - hadrian/src/Rules/Gmp.hs - hadrian/src/Settings/Packages.hs - libraries/base/changelog.md - libraries/ghc-internal/configure.ac - libraries/ghc-internal/include/HsIntegerGmp.h.in - linters/lint-codes/LintCodes/Static.hs - testsuite/tests/indexed-types/should_compile/CEqCanOccursCheck.hs - testsuite/tests/indexed-types/should_fail/T12522a.hs - testsuite/tests/indexed-types/should_fail/T26176.stderr - testsuite/tests/parser/should_fail/RecordDotSyntaxFail10.stderr - testsuite/tests/parser/should_fail/RecordDotSyntaxFail13.stderr - testsuite/tests/parser/should_fail/T20654a.stderr - testsuite/tests/pmcheck/should_compile/T15753c.hs - + testsuite/tests/pmcheck/should_compile/T15753c.stderr - testsuite/tests/pmcheck/should_compile/T15753d.hs - + testsuite/tests/pmcheck/should_compile/T15753d.stderr - + testsuite/tests/pmcheck/should_compile/T22652.hs - + testsuite/tests/pmcheck/should_compile/T22652a.hs - testsuite/tests/pmcheck/should_compile/all.T - + testsuite/tests/polykinds/T13882.hs - testsuite/tests/polykinds/all.T - testsuite/tests/quantified-constraints/T15316A.stderr - testsuite/tests/quantified-constraints/T17267.stderr - testsuite/tests/quantified-constraints/T17267a.stderr - testsuite/tests/quantified-constraints/T17267b.stderr - testsuite/tests/quantified-constraints/T17267c.stderr - testsuite/tests/quantified-constraints/T17267e.stderr - testsuite/tests/quantified-constraints/T17458.stderr - testsuite/tests/typecheck/should_compile/T16188.hs - testsuite/tests/typecheck/should_fail/ContextStack1.stderr - testsuite/tests/typecheck/should_fail/FD3.stderr - testsuite/tests/typecheck/should_fail/FDsFromGivens2.stderr - testsuite/tests/typecheck/should_fail/FunDepOrigin1b.stderr - testsuite/tests/typecheck/should_fail/T13506.stderr - testsuite/tests/typecheck/should_fail/T15767.stderr - testsuite/tests/typecheck/should_fail/T19415.stderr - testsuite/tests/typecheck/should_fail/T19415b.stderr - testsuite/tests/typecheck/should_fail/T22924b.stderr - + testsuite/tests/typecheck/should_fail/T23162b.hs - + testsuite/tests/typecheck/should_fail/T23162b.stderr - + testsuite/tests/typecheck/should_fail/T23162c.hs - + testsuite/tests/typecheck/should_fail/T23162d.hs - testsuite/tests/typecheck/should_fail/T25325.stderr - testsuite/tests/typecheck/should_fail/T5236.stderr - testsuite/tests/typecheck/should_fail/T5246.stderr - testsuite/tests/typecheck/should_fail/T5978.stderr - testsuite/tests/typecheck/should_fail/T9612.stderr - testsuite/tests/typecheck/should_fail/TcCoercibleFail.stderr - testsuite/tests/typecheck/should_fail/all.T - testsuite/tests/typecheck/should_fail/tcfail143.stderr - utils/haddock/haddock-api/src/Haddock/Convert.hs - − utils/iserv/cbits/iservmain.c - utils/iserv/iserv.cabal.in The diff was not included because it is too large. View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/28a7a94e987b9aefce6a20996279f2… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/28a7a94e987b9aefce6a20996279f2… You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][wip/T26682] 14 commits: [#26183] Associated Type Iface Fix
by Simon Peyton Jones (＠simonpj) 06 Jan '26

06 Jan '26

Simon Peyton Jones pushed to branch wip/T26682 at Glasgow Haskell Compiler / GHC Commits: 8a317b6f by Aaron Allen at 2026-01-01T03:05:15-05:00 [#26183] Associated Type Iface Fix When determining "extras" for class decl interface entries, axioms for the associated types need to included so that dependent modules will be recompiled if those axioms change. resolves #26183 - - - - - ae1aeaab by Cheng Shao at 2026-01-01T03:06:32-05:00 testsuite: run numeric tests with optasm when available This patch adds the `optasm` extra way to nueric tests when NCG is available. Some numeric bugs only surface with optimization, omitting this can hide these bugs and even make them slip into release! (e.g. #26711) - - - - - 6213bb57 by maralorn at 2026-01-02T16:30:32+01:00 GHC.Internal.Exception.Context: Fix comment on addExceptionAnnotation - - - - - b820ff50 by Janis Voigtlaender at 2026-01-05T02:43:18-05:00 GHC.Internal.Control.Monad.replicateM: Fix comment - - - - - a8a94aad by Cheng Shao at 2026-01-05T16:24:04-05:00 hadrian: drops unused PE linker script for windows This patch drops unused PE linker script for windows in the `MergeObjects` builder of hadrian. The linker script is used for merging object files into a single `HS*.o` object file and undoing the effect of split sections, when building the "ghci library" object file. However, we don't build the ghci library on windows, and this code path is actually unreachable. - - - - - 53038ea9 by Cheng Shao at 2026-01-05T16:24:04-05:00 hadrian: drop unused logic for building ghci libraries This patch drops the unused logic for building ghci libraries in hadrian: - The term "ghci library" refers to an optional object file per library `HS*.o`, which is merged from multiple object files in that library using the `MergeObjects` builder in hadrian. - The original rationale of having a ghci library object, in addition to normal archives, was to speedup ghci loading, since the combined object is linked with a linker script to undo the effects of `-fsplit-sections` to reduce section count and make it easier for the RTS linker to handle. - However, most GHC builds enable `dynamicGhcPrograms` by default, in such cases the ghci library would already not be built. - `dynamicGhcPrograms` is disabled on Windows, but still we don't build the ghci library due to lack of functioning merge objects command. - The only case that we actually build ghci library objects, are alpine fully static bindists. However, for other reasons, split sections is already disabled for fully static builds anyway! - There will not be any regression if the ghci library objects are absent from a GHC global libdir when `dynamicGhcPrograms` is disabled. The RTS linker can already load the archives without any issue. Hence the removal. We now forcibly disable ghci libraries for all Cabal components, and rip out all logic related to `MergeObjects` and ghci libraries in hadrian. This also nicely cleans up some old todos and fixmes that are no longer relevant. Note that MergeObjects in hadrian is not the same thing as merge objects in the GHC driver. The latter is not affected by this patch. ------------------------- Metric Decrease: libdir ------------------------- Co-authored-by: Codex <codex(a)openai.com> - - - - - 8f209336 by Simon Jakobi at 2026-01-05T16:24:48-05:00 User's guide: Fix link to language extensions Instead of linking to haddocks, it seemed more useful to link to the extension overview in the user's guide. Closes #26614. - - - - - 0b7df6db by Simon Peyton Jones at 2026-01-06T09:32:23-05:00 Improved fundeps for closed type families The big payload of this commit is to execute the plan suggested in #23162, by improving the way that we generate functional dependencies for closed type families. It is all described in Note [Exploiting closed type families] Most of the changes are in GHC.Tc.Solver.FunDeps Other small changes * GHC.Tc.Solver.bumpReductionDepth. This function brings together the code that * Bumps the depth * Checks for overflow Previously the two were separated, sometimes quite widely. * GHC.Core.Unify.niFixSubst: minor improvement, removing an unnecessary itraetion in the base case. * GHC.Core.Unify: no need to pass an InScopeSet to tcUnifyTysForInjectivity. It can calculate one for itself; and it is never inspected anyway so it's free to do so. * GHC.Tc.Errors.Ppr: slight impovement to the error message for reduction-stack overflow, when a constraint (rather than a type) is involved. * GHC.Tc.Solver.Monad.wrapUnifier: small change to the API - - - - - fde8bd88 by Simon Peyton Jones at 2026-01-06T09:32:23-05:00 Add missing (KK4) to kick-out criteria There was a missing case in kick-out that meant we could fail to solve an eminently-solvable constraint. See the new notes about (KK4) - - - - - 00082844 by Simon Peyton Jones at 2026-01-06T09:32:23-05:00 Some small refactorings of error reporting in the typechecker This is just a tidy-up commit. * Add ei_insoluble to ErrorItem, to cache insolubility. Small tidy-up. * Remove `is_ip` and `mkIPErr` from GHC.Tc.Errors; instead enhance mkDictErr to handle implicit parameters. Small refactor. - - - - - fe4cb252 by Simon Peyton Jones at 2026-01-06T09:32:24-05:00 Improve recording of insolubility for fundeps This commit addresses #22652, by recording when the fundeps for a constraint are definitely insoluble. That in turn improves the perspicacity of the pattern-match overlap checker. See Note [Insoluble fundeps] - - - - - df0ffaa5 by Simon Peyton Jones at 2026-01-06T09:32:24-05:00 Fix a buglet in niFixSubst The MR of which this is part failed an assertion check extendTvSubst because we extended the TvSubst with a CoVar. Boo. This tiny patch fixes it, and adds the regression test from #13882 that showed it up. - - - - - 3d6aba77 by konsumlamm at 2026-01-06T09:33:16-05:00 Fix changelog formatting - - - - - d30e8261 by Simon Peyton Jones at 2026-01-06T15:47:02+00:00 Fix scoping errors in specialisation Using -fspecialise-aggressively in #26682 showed up a couple of subtle errors in the type-class specialiser. * dumpBindUDs failed to call `deleteCallsMentioning`, resulting in a call that mentioned a dictionary that was not in scope. This call has been missing since 2009! commit c43c981705ec33da92a9ce91eb90f2ecf00be9fe Author: Simon Peyton Jones <simonpj(a)microsoft.com> Date: Fri Oct 23 16:15:51 2009 +0000 Fixed by re-combining `dumpBindUDs` and `dumpUDs`. * I think there was another bug involving the quantified type variables in polymorphic specialisation. In any case I refactored `specHeader` and `spec_call` so that the former looks for the extra quantified type variables rather than the latter. This is quite a worthwhile simplification: less code, easier to grok. Test case in simplCore/should_compile/T26682, brilliantly minimised by @sheaf. - - - - - 103 changed files: - compiler/GHC/Core/FamInstEnv.hs - compiler/GHC/Core/Opt/Specialise.hs - compiler/GHC/Core/TyCo/Subst.hs - compiler/GHC/Core/TyCon.hs - compiler/GHC/Core/Unify.hs - compiler/GHC/HsToCore/Monad.hs - compiler/GHC/Iface/Recomp.hs - compiler/GHC/Tc/Errors.hs - compiler/GHC/Tc/Errors/Ppr.hs - compiler/GHC/Tc/Errors/Types.hs - compiler/GHC/Tc/Gen/Splice.hs - compiler/GHC/Tc/Solver.hs - compiler/GHC/Tc/Solver/Default.hs - compiler/GHC/Tc/Solver/Dict.hs - compiler/GHC/Tc/Solver/Equality.hs - compiler/GHC/Tc/Solver/FunDeps.hs - compiler/GHC/Tc/Solver/InertSet.hs - compiler/GHC/Tc/Solver/Monad.hs - compiler/GHC/Tc/Solver/Rewrite.hs - compiler/GHC/Tc/Types/Constraint.hs - compiler/GHC/Tc/Types/CtLoc.hs - compiler/GHC/Tc/Utils/Monad.hs - compiler/GHC/Tc/Utils/Unify.hs - compiler/GHC/Types/TyThing.hs - docs/users_guide/9.16.1-notes.rst - docs/users_guide/exts/pragmas.rst - docs/users_guide/exts/table.rst - − driver/utils/merge_sections.ld - − driver/utils/merge_sections_pe.ld - hadrian/hadrian.cabal - hadrian/src/Builder.hs - hadrian/src/Context.hs - hadrian/src/Hadrian/Haskell/Cabal/Parse.hs - hadrian/src/Hadrian/Haskell/Cabal/Type.hs - hadrian/src/Hadrian/Haskell/Hash.hs - hadrian/src/Oracles/Flag.hs - hadrian/src/Rules.hs - hadrian/src/Rules/Library.hs - hadrian/src/Rules/Register.hs - hadrian/src/Settings/Builders/Cabal.hs - − hadrian/src/Settings/Builders/MergeObjects.hs - hadrian/src/Settings/Builders/SplitSections.hs - hadrian/src/Settings/Default.hs - hadrian/src/Settings/Packages.hs - libraries/base/changelog.md - libraries/ghc-internal/src/GHC/Internal/Control/Monad.hs - libraries/ghc-internal/src/GHC/Internal/Exception/Context.hs - linters/lint-codes/LintCodes/Static.hs - + testsuite/tests/driver/recomp26183/M.hs - + testsuite/tests/driver/recomp26183/M2A.hs - + testsuite/tests/driver/recomp26183/M2B.hs - + testsuite/tests/driver/recomp26183/Makefile - + testsuite/tests/driver/recomp26183/all.T - + testsuite/tests/driver/recomp26183/recomp26183.stderr - testsuite/tests/indexed-types/should_compile/CEqCanOccursCheck.hs - testsuite/tests/indexed-types/should_fail/T12522a.hs - testsuite/tests/indexed-types/should_fail/T26176.stderr - testsuite/tests/numeric/should_run/all.T - testsuite/tests/parser/should_fail/RecordDotSyntaxFail10.stderr - testsuite/tests/parser/should_fail/RecordDotSyntaxFail13.stderr - testsuite/tests/parser/should_fail/T20654a.stderr - testsuite/tests/pmcheck/should_compile/T15753c.hs - + testsuite/tests/pmcheck/should_compile/T15753c.stderr - testsuite/tests/pmcheck/should_compile/T15753d.hs - + testsuite/tests/pmcheck/should_compile/T15753d.stderr - + testsuite/tests/pmcheck/should_compile/T22652.hs - + testsuite/tests/pmcheck/should_compile/T22652a.hs - testsuite/tests/pmcheck/should_compile/all.T - + testsuite/tests/polykinds/T13882.hs - testsuite/tests/polykinds/all.T - testsuite/tests/quantified-constraints/T15316A.stderr - testsuite/tests/quantified-constraints/T17267.stderr - testsuite/tests/quantified-constraints/T17267a.stderr - testsuite/tests/quantified-constraints/T17267b.stderr - testsuite/tests/quantified-constraints/T17267c.stderr - testsuite/tests/quantified-constraints/T17267e.stderr - testsuite/tests/quantified-constraints/T17458.stderr - + testsuite/tests/simplCore/should_compile/T26682.hs - + testsuite/tests/simplCore/should_compile/T26682a.hs - testsuite/tests/simplCore/should_compile/all.T - testsuite/tests/typecheck/should_compile/T16188.hs - testsuite/tests/typecheck/should_fail/ContextStack1.stderr - testsuite/tests/typecheck/should_fail/FD3.stderr - testsuite/tests/typecheck/should_fail/FDsFromGivens2.stderr - testsuite/tests/typecheck/should_fail/FunDepOrigin1b.stderr - testsuite/tests/typecheck/should_fail/T13506.stderr - testsuite/tests/typecheck/should_fail/T15767.stderr - testsuite/tests/typecheck/should_fail/T19415.stderr - testsuite/tests/typecheck/should_fail/T19415b.stderr - testsuite/tests/typecheck/should_fail/T22924b.stderr - + testsuite/tests/typecheck/should_fail/T23162b.hs - + testsuite/tests/typecheck/should_fail/T23162b.stderr - + testsuite/tests/typecheck/should_fail/T23162c.hs - + testsuite/tests/typecheck/should_fail/T23162d.hs - testsuite/tests/typecheck/should_fail/T25325.stderr - testsuite/tests/typecheck/should_fail/T5236.stderr - testsuite/tests/typecheck/should_fail/T5246.stderr - testsuite/tests/typecheck/should_fail/T5978.stderr - testsuite/tests/typecheck/should_fail/T9612.stderr - testsuite/tests/typecheck/should_fail/TcCoercibleFail.stderr - testsuite/tests/typecheck/should_fail/all.T - testsuite/tests/typecheck/should_fail/tcfail143.stderr - utils/haddock/haddock-api/src/Haddock/Convert.hs The diff was not included because it is too large. View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/57219df7a1bad8d247c6a5ebb33fd5… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/57219df7a1bad8d247c6a5ebb33fd5… You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][wip/T26709] 15 commits: [#26183] Associated Type Iface Fix
by Simon Peyton Jones (＠simonpj) 06 Jan '26

06 Jan '26

Simon Peyton Jones pushed to branch wip/T26709 at Glasgow Haskell Compiler / GHC Commits: 8a317b6f by Aaron Allen at 2026-01-01T03:05:15-05:00 [#26183] Associated Type Iface Fix When determining "extras" for class decl interface entries, axioms for the associated types need to included so that dependent modules will be recompiled if those axioms change. resolves #26183 - - - - - ae1aeaab by Cheng Shao at 2026-01-01T03:06:32-05:00 testsuite: run numeric tests with optasm when available This patch adds the `optasm` extra way to nueric tests when NCG is available. Some numeric bugs only surface with optimization, omitting this can hide these bugs and even make them slip into release! (e.g. #26711) - - - - - 6213bb57 by maralorn at 2026-01-02T16:30:32+01:00 GHC.Internal.Exception.Context: Fix comment on addExceptionAnnotation - - - - - b820ff50 by Janis Voigtlaender at 2026-01-05T02:43:18-05:00 GHC.Internal.Control.Monad.replicateM: Fix comment - - - - - a8a94aad by Cheng Shao at 2026-01-05T16:24:04-05:00 hadrian: drops unused PE linker script for windows This patch drops unused PE linker script for windows in the `MergeObjects` builder of hadrian. The linker script is used for merging object files into a single `HS*.o` object file and undoing the effect of split sections, when building the "ghci library" object file. However, we don't build the ghci library on windows, and this code path is actually unreachable. - - - - - 53038ea9 by Cheng Shao at 2026-01-05T16:24:04-05:00 hadrian: drop unused logic for building ghci libraries This patch drops the unused logic for building ghci libraries in hadrian: - The term "ghci library" refers to an optional object file per library `HS*.o`, which is merged from multiple object files in that library using the `MergeObjects` builder in hadrian. - The original rationale of having a ghci library object, in addition to normal archives, was to speedup ghci loading, since the combined object is linked with a linker script to undo the effects of `-fsplit-sections` to reduce section count and make it easier for the RTS linker to handle. - However, most GHC builds enable `dynamicGhcPrograms` by default, in such cases the ghci library would already not be built. - `dynamicGhcPrograms` is disabled on Windows, but still we don't build the ghci library due to lack of functioning merge objects command. - The only case that we actually build ghci library objects, are alpine fully static bindists. However, for other reasons, split sections is already disabled for fully static builds anyway! - There will not be any regression if the ghci library objects are absent from a GHC global libdir when `dynamicGhcPrograms` is disabled. The RTS linker can already load the archives without any issue. Hence the removal. We now forcibly disable ghci libraries for all Cabal components, and rip out all logic related to `MergeObjects` and ghci libraries in hadrian. This also nicely cleans up some old todos and fixmes that are no longer relevant. Note that MergeObjects in hadrian is not the same thing as merge objects in the GHC driver. The latter is not affected by this patch. ------------------------- Metric Decrease: libdir ------------------------- Co-authored-by: Codex <codex(a)openai.com> - - - - - 8f209336 by Simon Jakobi at 2026-01-05T16:24:48-05:00 User's guide: Fix link to language extensions Instead of linking to haddocks, it seemed more useful to link to the extension overview in the user's guide. Closes #26614. - - - - - 0b7df6db by Simon Peyton Jones at 2026-01-06T09:32:23-05:00 Improved fundeps for closed type families The big payload of this commit is to execute the plan suggested in #23162, by improving the way that we generate functional dependencies for closed type families. It is all described in Note [Exploiting closed type families] Most of the changes are in GHC.Tc.Solver.FunDeps Other small changes * GHC.Tc.Solver.bumpReductionDepth. This function brings together the code that * Bumps the depth * Checks for overflow Previously the two were separated, sometimes quite widely. * GHC.Core.Unify.niFixSubst: minor improvement, removing an unnecessary itraetion in the base case. * GHC.Core.Unify: no need to pass an InScopeSet to tcUnifyTysForInjectivity. It can calculate one for itself; and it is never inspected anyway so it's free to do so. * GHC.Tc.Errors.Ppr: slight impovement to the error message for reduction-stack overflow, when a constraint (rather than a type) is involved. * GHC.Tc.Solver.Monad.wrapUnifier: small change to the API - - - - - fde8bd88 by Simon Peyton Jones at 2026-01-06T09:32:23-05:00 Add missing (KK4) to kick-out criteria There was a missing case in kick-out that meant we could fail to solve an eminently-solvable constraint. See the new notes about (KK4) - - - - - 00082844 by Simon Peyton Jones at 2026-01-06T09:32:23-05:00 Some small refactorings of error reporting in the typechecker This is just a tidy-up commit. * Add ei_insoluble to ErrorItem, to cache insolubility. Small tidy-up. * Remove `is_ip` and `mkIPErr` from GHC.Tc.Errors; instead enhance mkDictErr to handle implicit parameters. Small refactor. - - - - - fe4cb252 by Simon Peyton Jones at 2026-01-06T09:32:24-05:00 Improve recording of insolubility for fundeps This commit addresses #22652, by recording when the fundeps for a constraint are definitely insoluble. That in turn improves the perspicacity of the pattern-match overlap checker. See Note [Insoluble fundeps] - - - - - df0ffaa5 by Simon Peyton Jones at 2026-01-06T09:32:24-05:00 Fix a buglet in niFixSubst The MR of which this is part failed an assertion check extendTvSubst because we extended the TvSubst with a CoVar. Boo. This tiny patch fixes it, and adds the regression test from #13882 that showed it up. - - - - - 3d6aba77 by konsumlamm at 2026-01-06T09:33:16-05:00 Fix changelog formatting - - - - - 5358fe3f by Simon Peyton Jones at 2026-01-06T15:38:11+00:00 Refactor srutOkForBinderSwap This MR does a small refactor: * Moves `scrutOkForBinderSwap` and `BinderSwapDecision` to GHC.Core.Utils * Inverts the sense of the coercion it returns, which makes more sense No effect on behaviour - - - - - a6ca9f04 by Simon Peyton Jones at 2026-01-06T15:38:11+00:00 Improve case merging This small MR makes case merging happen a bit more often than it otherwise could, by getting join points out of the way. See #26709 and GHC.Core.Utils Note [Floating join points out of DEFAULT alternatives] - - - - - 107 changed files: - compiler/GHC/Core/FamInstEnv.hs - compiler/GHC/Core/Opt/OccurAnal.hs - compiler/GHC/Core/Opt/Simplify/Iteration.hs - compiler/GHC/Core/Opt/Simplify/Utils.hs - compiler/GHC/Core/Opt/SpecConstr.hs - compiler/GHC/Core/TyCo/Subst.hs - compiler/GHC/Core/TyCon.hs - compiler/GHC/Core/Unify.hs - compiler/GHC/Core/Utils.hs - compiler/GHC/HsToCore/Monad.hs - compiler/GHC/Iface/Recomp.hs - compiler/GHC/Tc/Errors.hs - compiler/GHC/Tc/Errors/Ppr.hs - compiler/GHC/Tc/Errors/Types.hs - compiler/GHC/Tc/Gen/Splice.hs - compiler/GHC/Tc/Solver.hs - compiler/GHC/Tc/Solver/Default.hs - compiler/GHC/Tc/Solver/Dict.hs - compiler/GHC/Tc/Solver/Equality.hs - compiler/GHC/Tc/Solver/FunDeps.hs - compiler/GHC/Tc/Solver/InertSet.hs - compiler/GHC/Tc/Solver/Monad.hs - compiler/GHC/Tc/Solver/Rewrite.hs - compiler/GHC/Tc/Types/Constraint.hs - compiler/GHC/Tc/Types/CtLoc.hs - compiler/GHC/Tc/Utils/Monad.hs - compiler/GHC/Tc/Utils/Unify.hs - compiler/GHC/Types/TyThing.hs - docs/users_guide/9.16.1-notes.rst - docs/users_guide/exts/pragmas.rst - docs/users_guide/exts/table.rst - − driver/utils/merge_sections.ld - − driver/utils/merge_sections_pe.ld - hadrian/hadrian.cabal - hadrian/src/Builder.hs - hadrian/src/Context.hs - hadrian/src/Hadrian/Haskell/Cabal/Parse.hs - hadrian/src/Hadrian/Haskell/Cabal/Type.hs - hadrian/src/Hadrian/Haskell/Hash.hs - hadrian/src/Oracles/Flag.hs - hadrian/src/Rules.hs - hadrian/src/Rules/Library.hs - hadrian/src/Rules/Register.hs - hadrian/src/Settings/Builders/Cabal.hs - − hadrian/src/Settings/Builders/MergeObjects.hs - hadrian/src/Settings/Builders/SplitSections.hs - hadrian/src/Settings/Default.hs - hadrian/src/Settings/Packages.hs - libraries/base/changelog.md - libraries/ghc-internal/src/GHC/Internal/Control/Monad.hs - libraries/ghc-internal/src/GHC/Internal/Exception/Context.hs - linters/lint-codes/LintCodes/Static.hs - + testsuite/tests/driver/recomp26183/M.hs - + testsuite/tests/driver/recomp26183/M2A.hs - + testsuite/tests/driver/recomp26183/M2B.hs - + testsuite/tests/driver/recomp26183/Makefile - + testsuite/tests/driver/recomp26183/all.T - + testsuite/tests/driver/recomp26183/recomp26183.stderr - testsuite/tests/indexed-types/should_compile/CEqCanOccursCheck.hs - testsuite/tests/indexed-types/should_fail/T12522a.hs - testsuite/tests/indexed-types/should_fail/T26176.stderr - testsuite/tests/numeric/should_run/all.T - testsuite/tests/parser/should_fail/RecordDotSyntaxFail10.stderr - testsuite/tests/parser/should_fail/RecordDotSyntaxFail13.stderr - testsuite/tests/parser/should_fail/T20654a.stderr - testsuite/tests/pmcheck/should_compile/T15753c.hs - + testsuite/tests/pmcheck/should_compile/T15753c.stderr - testsuite/tests/pmcheck/should_compile/T15753d.hs - + testsuite/tests/pmcheck/should_compile/T15753d.stderr - + testsuite/tests/pmcheck/should_compile/T22652.hs - + testsuite/tests/pmcheck/should_compile/T22652a.hs - testsuite/tests/pmcheck/should_compile/all.T - + testsuite/tests/polykinds/T13882.hs - testsuite/tests/polykinds/all.T - testsuite/tests/quantified-constraints/T15316A.stderr - testsuite/tests/quantified-constraints/T17267.stderr - testsuite/tests/quantified-constraints/T17267a.stderr - testsuite/tests/quantified-constraints/T17267b.stderr - testsuite/tests/quantified-constraints/T17267c.stderr - testsuite/tests/quantified-constraints/T17267e.stderr - testsuite/tests/quantified-constraints/T17458.stderr - + testsuite/tests/simplCore/should_compile/T26709.hs - + testsuite/tests/simplCore/should_compile/T26709.stderr - testsuite/tests/simplCore/should_compile/all.T - testsuite/tests/typecheck/should_compile/T16188.hs - testsuite/tests/typecheck/should_fail/ContextStack1.stderr - testsuite/tests/typecheck/should_fail/FD3.stderr - testsuite/tests/typecheck/should_fail/FDsFromGivens2.stderr - testsuite/tests/typecheck/should_fail/FunDepOrigin1b.stderr - testsuite/tests/typecheck/should_fail/T13506.stderr - testsuite/tests/typecheck/should_fail/T15767.stderr - testsuite/tests/typecheck/should_fail/T19415.stderr - testsuite/tests/typecheck/should_fail/T19415b.stderr - testsuite/tests/typecheck/should_fail/T22924b.stderr - + testsuite/tests/typecheck/should_fail/T23162b.hs - + testsuite/tests/typecheck/should_fail/T23162b.stderr - + testsuite/tests/typecheck/should_fail/T23162c.hs - + testsuite/tests/typecheck/should_fail/T23162d.hs - testsuite/tests/typecheck/should_fail/T25325.stderr - testsuite/tests/typecheck/should_fail/T5236.stderr - testsuite/tests/typecheck/should_fail/T5246.stderr - testsuite/tests/typecheck/should_fail/T5978.stderr - testsuite/tests/typecheck/should_fail/T9612.stderr - testsuite/tests/typecheck/should_fail/TcCoercibleFail.stderr - testsuite/tests/typecheck/should_fail/all.T - testsuite/tests/typecheck/should_fail/tcfail143.stderr - utils/haddock/haddock-api/src/Haddock/Convert.hs The diff was not included because it is too large. View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/e091ab8d381d0b588d4d32213d4eff… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/e091ab8d381d0b588d4d32213d4eff… You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][wip/T26681] Add missing InVar->OutVar lookup in SetLevels
by Simon Peyton Jones (＠simonpj) 06 Jan '26

06 Jan '26

Simon Peyton Jones pushed to branch wip/T26681 at Glasgow Haskell Compiler / GHC Commits: 824fe52d by Simon Peyton Jones at 2026-01-06T15:34:59+00:00 Add missing InVar->OutVar lookup in SetLevels As #26681 showed, the SetLevels pass was failing to map an InVar to an OutVar. Very silly! I'm amazed it hasn't broken before now. I have improved the type singatures (to mention InVar and OutVar) so it's more obvious what needs to happen. - - - - - 3 changed files: - compiler/GHC/Core/Opt/SetLevels.hs - + testsuite/tests/simplCore/should_compile/T26681.hs - testsuite/tests/simplCore/should_compile/all.T Changes: ===================================== compiler/GHC/Core/Opt/SetLevels.hs ===================================== @@ -91,6 +91,7 @@ import GHC.Core.Utils import GHC.Core.Opt.Arity ( exprBotStrictness_maybe, isOneShotBndr ) import GHC.Core.FVs -- all of it import GHC.Core.Subst +import GHC.Core.TyCo.Subst( lookupTyVar ) import GHC.Core.Make ( sortQuantVars ) import GHC.Core.Type ( Type, tyCoVarsOfType , mightBeUnliftedType, closeOverKindsDSet @@ -466,8 +467,8 @@ lvlCase env scrut_fvs scrut' case_bndr ty alts ty' = substTyUnchecked (le_subst env) ty incd_lvl = incMinorLvl (le_ctxt_lvl env) - dest_lvl = maxFvLevel (const True) env scrut_fvs - -- Don't abstract over type variables, hence const True + dest_lvl = maxFvLevel includeTyVars env scrut_fvs + -- Don't abstract over type variables, hence includeTyVars lvl_alt alts_env (AnnAlt con bs rhs) = do { rhs' <- lvlMFE new_env True rhs @@ -719,8 +720,11 @@ hasFreeJoin :: LevelEnv -> DVarSet -> Bool -- (In the latter case it won't be a join point any more.) -- Not treating top-level ones specially had a massive effect -- on nofib/minimax/Prog.prog -hasFreeJoin env fvs - = not (maxFvLevel isJoinId env fvs == tOP_LEVEL) +hasFreeJoin env fvs = anyDVarSet bad_join fvs + where + bad_join v = isJoinId v && + maxIn True env v tOP_LEVEL /= tOP_LEVEL + {- Note [Saving work] ~~~~~~~~~~~~~~~~~~~~~ @@ -1607,10 +1611,10 @@ destLevel env fvs fvs_ty is_function is_bot | otherwise = max_fv_id_level where - max_fv_id_level = maxFvLevel isId env fvs -- Max over Ids only; the - -- tyvars will be abstracted + max_fv_id_level = maxFvLevel idsOnly env fvs -- Max over Ids only; the + -- tyvars will be abstracted - as_far_as_poss = maxFvLevel' isId env fvs_ty + as_far_as_poss = maxFvLevel' idsOnly env fvs_ty -- See Note [Floating and kind casts] {- Note [Floating and kind casts] @@ -1768,28 +1772,47 @@ extendCaseBndrEnv le@(LE { le_subst = subst, le_env = id_env }) , le_env = add_id id_env (case_bndr, scrut_var) } extendCaseBndrEnv env _ _ = env -maxFvLevel :: (Var -> Bool) -> LevelEnv -> DVarSet -> Level -maxFvLevel max_me env var_set - = nonDetStrictFoldDVarSet (maxIn max_me env) tOP_LEVEL var_set +includeTyVars, idsOnly :: Bool +idsOnly = False +includeTyVars = True + +maxFvLevel :: Bool -> LevelEnv -> DVarSet -> Level +maxFvLevel include_tyvars env var_set + = nonDetStrictFoldDVarSet (maxIn include_tyvars env) tOP_LEVEL var_set -- It's OK to use a non-deterministic fold here because maxIn commutes. -maxFvLevel' :: (Var -> Bool) -> LevelEnv -> TyCoVarSet -> Level +maxFvLevel' :: Bool -> LevelEnv -> TyCoVarSet -> Level -- Same but for TyCoVarSet -maxFvLevel' max_me env var_set - = nonDetStrictFoldUniqSet (maxIn max_me env) tOP_LEVEL var_set +maxFvLevel' include_tyvars env var_set + = nonDetStrictFoldUniqSet (maxIn include_tyvars env) tOP_LEVEL var_set -- It's OK to use a non-deterministic fold here because maxIn commutes. -maxIn :: (Var -> Bool) -> LevelEnv -> InVar -> Level -> Level -maxIn max_me (LE { le_lvl_env = lvl_env, le_env = id_env }) in_var lvl +maxIn :: Bool -> LevelEnv -> InVar -> Level -> Level +-- True <=> include tyvars +maxIn include_tyvars env@(LE { le_subst = subst, le_env = id_env }) in_var lvl + | isId in_var = case lookupVarEnv id_env in_var of + Nothing -> maxOut env in_var lvl Just (abs_vars, _) -> foldr max_out lvl abs_vars - Nothing -> max_out in_var lvl - where - max_out out_var lvl - | max_me out_var = case lookupVarEnv lvl_env out_var of - Just lvl' -> maxLvl lvl' lvl - Nothing -> lvl - | otherwise = lvl -- Ignore some vars depending on max_me + where + max_out out_var lvl + | isTyVar out_var && not include_tyvars + = lvl + | otherwise = maxOut env out_var lvl + + | include_tyvars -- TyVars + = case lookupTyVar subst in_var of + Just ty -> nonDetStrictFoldVarSet (maxOut env) lvl (tyCoVarsOfType ty) + Nothing -> maxOut env in_var lvl + + | otherwise -- Ignore free tyvars + = lvl + +maxOut :: LevelEnv -> OutVar -> Level -> Level +maxOut (LE { le_lvl_env = lvl_env }) out_var lvl + = case lookupVarEnv lvl_env out_var of + Just lvl' -> maxLvl lvl' lvl + Nothing -> lvl lookupVar :: LevelEnv -> Id -> LevelledExpr lookupVar le v = case lookupVarEnv (le_env le) v of ===================================== testsuite/tests/simplCore/should_compile/T26681.hs ===================================== @@ -0,0 +1,47 @@ +{-# LANGUAGE BangPatterns #-} +{-# LANGUAGE DataKinds #-} +{-# LANGUAGE GADTs #-} +{-# LANGUAGE PolyKinds #-} +{-# LANGUAGE ScopedTypeVariables #-} +{-# LANGUAGE StandaloneKindSignatures #-} +{-# LANGUAGE TypeApplications #-} +{-# LANGUAGE TypeFamilies #-} +{-# LANGUAGE TypeOperators #-} + +module T26681 where + +import Data.Kind (Type) +import Data.Type.Equality +import GHC.TypeLits +import qualified Unsafe.Coerce + + +{-# NOINLINE unsafeCoerceRefl #-} +unsafeCoerceRefl :: a :~: b +unsafeCoerceRefl = Unsafe.Coerce.unsafeCoerce Refl + +type family MapJust l where + MapJust '[] = '[] + MapJust (x : xs) = Just x : MapJust xs + +type family Tail l where + Tail (_ : xs) = xs + +lemMapJustCons :: MapJust sh :~: Just n : sh' -> sh :~: n : Tail sh +lemMapJustCons Refl = unsafeCoerceRefl + + +type ListX :: [Maybe Nat] -> (Maybe Nat -> Type) -> Type +data ListX sh f where + ConsX :: !(f n) -> ListX (n : sh) f + + +data JustN n where + JustN :: JustN (Just n) + +data UnconsListSRes f sh1 = forall n sh. (n : sh ~ sh1) => UnconsListSRes + +listsUncons :: forall sh1 f. ListX (MapJust sh1) JustN -> UnconsListSRes f sh1 +listsUncons (ConsX JustN) + | Refl <- lemMapJustCons @sh1 Refl + = UnconsListSRes ===================================== testsuite/tests/simplCore/should_compile/all.T ===================================== @@ -563,3 +563,4 @@ test('T26115', [grep_errmsg(r'DFun')], compile, ['-O -ddump-simpl -dsuppress-uni test('T26116', normal, compile, ['-O -ddump-rules']) test('T26117', [grep_errmsg(r'==')], compile, ['-O -ddump-simpl -dsuppress-uniques']) test('T26349', normal, compile, ['-O -ddump-rules']) +test('T26681', normal, compile, ['-O']) View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/824fe52dea5322a3d76251895ca02f6… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/824fe52dea5322a3d76251895ca02f6… You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][wip/T26681] 16 commits: Decoupling Language.Haskell.Syntax.Binds from GHC.Types.Basic
by Simon Peyton Jones (＠simonpj) 06 Jan '26

06 Jan '26

Simon Peyton Jones pushed to branch wip/T26681 at Glasgow Haskell Compiler / GHC Commits: 7b9c20f4 by Recursion Ninja at 2025-12-24T10:35:36-05:00 Decoupling Language.Haskell.Syntax.Binds from GHC.Types.Basic by transferring InlinePragma types between the modules. * Moved InlinePragma data-types to Language.Haskell.Syntax.Binds.InlinePragma * Partitioned of Arity type synonyms to GHC.Types.Arity * InlinePragma is now extensible via Trees That Grow * Activation is now extensible via Trees That Grow * Maybe Arity change to more descriptive InlineSaturation data-type * InlineSaturation information removed from InlinePragma during GHS parsing pass * Cleaned up the exposed module interfaces of the new modules - - - - - a3afae0c by Simon Peyton Jones at 2025-12-25T15:26:36-05:00 Check for rubbish literals in Lint Addresses #26607. See new Note [Checking for rubbish literals] in GHC.Core.Lint - - - - - 8a317b6f by Aaron Allen at 2026-01-01T03:05:15-05:00 [#26183] Associated Type Iface Fix When determining "extras" for class decl interface entries, axioms for the associated types need to included so that dependent modules will be recompiled if those axioms change. resolves #26183 - - - - - ae1aeaab by Cheng Shao at 2026-01-01T03:06:32-05:00 testsuite: run numeric tests with optasm when available This patch adds the `optasm` extra way to nueric tests when NCG is available. Some numeric bugs only surface with optimization, omitting this can hide these bugs and even make them slip into release! (e.g. #26711) - - - - - 6213bb57 by maralorn at 2026-01-02T16:30:32+01:00 GHC.Internal.Exception.Context: Fix comment on addExceptionAnnotation - - - - - b820ff50 by Janis Voigtlaender at 2026-01-05T02:43:18-05:00 GHC.Internal.Control.Monad.replicateM: Fix comment - - - - - a8a94aad by Cheng Shao at 2026-01-05T16:24:04-05:00 hadrian: drops unused PE linker script for windows This patch drops unused PE linker script for windows in the `MergeObjects` builder of hadrian. The linker script is used for merging object files into a single `HS*.o` object file and undoing the effect of split sections, when building the "ghci library" object file. However, we don't build the ghci library on windows, and this code path is actually unreachable. - - - - - 53038ea9 by Cheng Shao at 2026-01-05T16:24:04-05:00 hadrian: drop unused logic for building ghci libraries This patch drops the unused logic for building ghci libraries in hadrian: - The term "ghci library" refers to an optional object file per library `HS*.o`, which is merged from multiple object files in that library using the `MergeObjects` builder in hadrian. - The original rationale of having a ghci library object, in addition to normal archives, was to speedup ghci loading, since the combined object is linked with a linker script to undo the effects of `-fsplit-sections` to reduce section count and make it easier for the RTS linker to handle. - However, most GHC builds enable `dynamicGhcPrograms` by default, in such cases the ghci library would already not be built. - `dynamicGhcPrograms` is disabled on Windows, but still we don't build the ghci library due to lack of functioning merge objects command. - The only case that we actually build ghci library objects, are alpine fully static bindists. However, for other reasons, split sections is already disabled for fully static builds anyway! - There will not be any regression if the ghci library objects are absent from a GHC global libdir when `dynamicGhcPrograms` is disabled. The RTS linker can already load the archives without any issue. Hence the removal. We now forcibly disable ghci libraries for all Cabal components, and rip out all logic related to `MergeObjects` and ghci libraries in hadrian. This also nicely cleans up some old todos and fixmes that are no longer relevant. Note that MergeObjects in hadrian is not the same thing as merge objects in the GHC driver. The latter is not affected by this patch. ------------------------- Metric Decrease: libdir ------------------------- Co-authored-by: Codex <codex(a)openai.com> - - - - - 8f209336 by Simon Jakobi at 2026-01-05T16:24:48-05:00 User's guide: Fix link to language extensions Instead of linking to haddocks, it seemed more useful to link to the extension overview in the user's guide. Closes #26614. - - - - - 0b7df6db by Simon Peyton Jones at 2026-01-06T09:32:23-05:00 Improved fundeps for closed type families The big payload of this commit is to execute the plan suggested in #23162, by improving the way that we generate functional dependencies for closed type families. It is all described in Note [Exploiting closed type families] Most of the changes are in GHC.Tc.Solver.FunDeps Other small changes * GHC.Tc.Solver.bumpReductionDepth. This function brings together the code that * Bumps the depth * Checks for overflow Previously the two were separated, sometimes quite widely. * GHC.Core.Unify.niFixSubst: minor improvement, removing an unnecessary itraetion in the base case. * GHC.Core.Unify: no need to pass an InScopeSet to tcUnifyTysForInjectivity. It can calculate one for itself; and it is never inspected anyway so it's free to do so. * GHC.Tc.Errors.Ppr: slight impovement to the error message for reduction-stack overflow, when a constraint (rather than a type) is involved. * GHC.Tc.Solver.Monad.wrapUnifier: small change to the API - - - - - fde8bd88 by Simon Peyton Jones at 2026-01-06T09:32:23-05:00 Add missing (KK4) to kick-out criteria There was a missing case in kick-out that meant we could fail to solve an eminently-solvable constraint. See the new notes about (KK4) - - - - - 00082844 by Simon Peyton Jones at 2026-01-06T09:32:23-05:00 Some small refactorings of error reporting in the typechecker This is just a tidy-up commit. * Add ei_insoluble to ErrorItem, to cache insolubility. Small tidy-up. * Remove `is_ip` and `mkIPErr` from GHC.Tc.Errors; instead enhance mkDictErr to handle implicit parameters. Small refactor. - - - - - fe4cb252 by Simon Peyton Jones at 2026-01-06T09:32:24-05:00 Improve recording of insolubility for fundeps This commit addresses #22652, by recording when the fundeps for a constraint are definitely insoluble. That in turn improves the perspicacity of the pattern-match overlap checker. See Note [Insoluble fundeps] - - - - - df0ffaa5 by Simon Peyton Jones at 2026-01-06T09:32:24-05:00 Fix a buglet in niFixSubst The MR of which this is part failed an assertion check extendTvSubst because we extended the TvSubst with a CoVar. Boo. This tiny patch fixes it, and adds the regression test from #13882 that showed it up. - - - - - 3d6aba77 by konsumlamm at 2026-01-06T09:33:16-05:00 Fix changelog formatting - - - - - 4f280cc2 by Simon Peyton Jones at 2026-01-06T15:31:52+00:00 Add missing InVar->OutVar lookup in SetLevels As #26681 showed, the SetLevels pass was failing to map an InVar to an OutVar. Very silly! I'm amazed it hasn't broken before now. I have improved the type singatures (to mention InVar and OutVar) so it's more obvious what needs to happen. - - - - - 168 changed files: - compiler/GHC/Builtin/PrimOps/Ids.hs - compiler/GHC/Core.hs - compiler/GHC/Core/FamInstEnv.hs - compiler/GHC/Core/Lint.hs - compiler/GHC/Core/Opt/CSE.hs - compiler/GHC/Core/Opt/CprAnal.hs - compiler/GHC/Core/Opt/DmdAnal.hs - compiler/GHC/Core/Opt/OccurAnal.hs - compiler/GHC/Core/Opt/Pipeline.hs - compiler/GHC/Core/Opt/Pipeline/Types.hs - compiler/GHC/Core/Opt/SetLevels.hs - compiler/GHC/Core/Opt/Simplify.hs - compiler/GHC/Core/Opt/Simplify/Env.hs - compiler/GHC/Core/Opt/Simplify/Iteration.hs - compiler/GHC/Core/Opt/Simplify/Utils.hs - compiler/GHC/Core/Opt/SpecConstr.hs - compiler/GHC/Core/Opt/Specialise.hs - compiler/GHC/Core/Opt/WorkWrap.hs - compiler/GHC/Core/Ppr.hs - compiler/GHC/Core/Rules.hs - compiler/GHC/Core/SimpleOpt.hs - compiler/GHC/Core/TyCo/Subst.hs - compiler/GHC/Core/TyCon.hs - compiler/GHC/Core/Unfold/Make.hs - compiler/GHC/Core/Unify.hs - compiler/GHC/Core/Utils.hs - compiler/GHC/CoreToIface.hs - compiler/GHC/Driver/Config/Core/Lint.hs - compiler/GHC/Driver/Config/Core/Lint/Interactive.hs - compiler/GHC/Driver/Config/Core/Opt/Simplify.hs - compiler/GHC/Hs/Binds.hs - compiler/GHC/Hs/Instances.hs - compiler/GHC/HsToCore.hs - compiler/GHC/HsToCore/Binds.hs - compiler/GHC/HsToCore/Errors/Types.hs - compiler/GHC/HsToCore/Foreign/C.hs - compiler/GHC/HsToCore/Foreign/JavaScript.hs - compiler/GHC/HsToCore/Monad.hs - compiler/GHC/HsToCore/Quote.hs - compiler/GHC/HsToCore/Ticks.hs - compiler/GHC/Iface/Make.hs - compiler/GHC/Iface/Recomp.hs - compiler/GHC/Iface/Syntax.hs - compiler/GHC/Iface/Tidy.hs - compiler/GHC/IfaceToCore.hs - compiler/GHC/Parser.y - compiler/GHC/Parser/Lexer.x - compiler/GHC/Parser/PostProcess.hs - compiler/GHC/Rename/Bind.hs - compiler/GHC/Tc/Deriv/Generics.hs - compiler/GHC/Tc/Errors.hs - compiler/GHC/Tc/Errors/Ppr.hs - compiler/GHC/Tc/Errors/Types.hs - compiler/GHC/Tc/Gen/Arrow.hs - compiler/GHC/Tc/Gen/Sig.hs - compiler/GHC/Tc/Gen/Splice.hs - compiler/GHC/Tc/Instance/Typeable.hs - compiler/GHC/Tc/Solver.hs - compiler/GHC/Tc/Solver/Default.hs - compiler/GHC/Tc/Solver/Dict.hs - compiler/GHC/Tc/Solver/Equality.hs - compiler/GHC/Tc/Solver/FunDeps.hs - compiler/GHC/Tc/Solver/InertSet.hs - compiler/GHC/Tc/Solver/Monad.hs - compiler/GHC/Tc/Solver/Rewrite.hs - compiler/GHC/Tc/TyCl/Instance.hs - compiler/GHC/Tc/Types/Constraint.hs - compiler/GHC/Tc/Types/CtLoc.hs - compiler/GHC/Tc/Utils/Instantiate.hs - compiler/GHC/Tc/Utils/Monad.hs - compiler/GHC/Tc/Utils/Unify.hs - compiler/GHC/ThToHs.hs - + compiler/GHC/Types/Arity.hs - compiler/GHC/Types/Basic.hs - compiler/GHC/Types/Hint.hs - compiler/GHC/Types/Id.hs - compiler/GHC/Types/Id/Info.hs - compiler/GHC/Types/Id/Make.hs - + compiler/GHC/Types/InlinePragma.hs - compiler/GHC/Types/TyThing.hs - compiler/GHC/Utils/Binary.hs - compiler/GHC/Utils/Outputable.hs - compiler/Language/Haskell/Syntax/Binds.hs - + compiler/Language/Haskell/Syntax/Binds/InlinePragma.hs - compiler/Language/Haskell/Syntax/Decls.hs - compiler/Language/Haskell/Syntax/Extension.hs - compiler/ghc.cabal.in - docs/users_guide/9.16.1-notes.rst - docs/users_guide/exts/pragmas.rst - docs/users_guide/exts/table.rst - − driver/utils/merge_sections.ld - − driver/utils/merge_sections_pe.ld - hadrian/hadrian.cabal - hadrian/src/Builder.hs - hadrian/src/Context.hs - hadrian/src/Hadrian/Haskell/Cabal/Parse.hs - hadrian/src/Hadrian/Haskell/Cabal/Type.hs - hadrian/src/Hadrian/Haskell/Hash.hs - hadrian/src/Oracles/Flag.hs - hadrian/src/Rules.hs - hadrian/src/Rules/Library.hs - hadrian/src/Rules/Register.hs - hadrian/src/Settings/Builders/Cabal.hs - − hadrian/src/Settings/Builders/MergeObjects.hs - hadrian/src/Settings/Builders/SplitSections.hs - hadrian/src/Settings/Default.hs - hadrian/src/Settings/Packages.hs - libraries/base/changelog.md - libraries/ghc-internal/src/GHC/Internal/Control/Monad.hs - libraries/ghc-internal/src/GHC/Internal/Exception/Context.hs - linters/lint-codes/LintCodes/Static.hs - testsuite/tests/count-deps/CountDepsAst.stdout - testsuite/tests/count-deps/CountDepsParser.stdout - + testsuite/tests/driver/recomp26183/M.hs - + testsuite/tests/driver/recomp26183/M2A.hs - + testsuite/tests/driver/recomp26183/M2B.hs - + testsuite/tests/driver/recomp26183/Makefile - + testsuite/tests/driver/recomp26183/all.T - + testsuite/tests/driver/recomp26183/recomp26183.stderr - testsuite/tests/indexed-types/should_compile/CEqCanOccursCheck.hs - testsuite/tests/indexed-types/should_fail/T12522a.hs - testsuite/tests/indexed-types/should_fail/T26176.stderr - testsuite/tests/numeric/should_run/all.T - testsuite/tests/parser/should_fail/RecordDotSyntaxFail10.stderr - testsuite/tests/parser/should_fail/RecordDotSyntaxFail13.stderr - testsuite/tests/parser/should_fail/T20654a.stderr - testsuite/tests/pmcheck/should_compile/T15753c.hs - + testsuite/tests/pmcheck/should_compile/T15753c.stderr - testsuite/tests/pmcheck/should_compile/T15753d.hs - + testsuite/tests/pmcheck/should_compile/T15753d.stderr - + testsuite/tests/pmcheck/should_compile/T22652.hs - + testsuite/tests/pmcheck/should_compile/T22652a.hs - testsuite/tests/pmcheck/should_compile/all.T - + testsuite/tests/polykinds/T13882.hs - testsuite/tests/polykinds/all.T - testsuite/tests/quantified-constraints/T15316A.stderr - testsuite/tests/quantified-constraints/T17267.stderr - testsuite/tests/quantified-constraints/T17267a.stderr - testsuite/tests/quantified-constraints/T17267b.stderr - testsuite/tests/quantified-constraints/T17267c.stderr - testsuite/tests/quantified-constraints/T17267e.stderr - testsuite/tests/quantified-constraints/T17458.stderr - + testsuite/tests/simplCore/should_compile/T26681.hs - testsuite/tests/simplCore/should_compile/all.T - testsuite/tests/typecheck/should_compile/T16188.hs - testsuite/tests/typecheck/should_fail/ContextStack1.stderr - testsuite/tests/typecheck/should_fail/FD3.stderr - testsuite/tests/typecheck/should_fail/FDsFromGivens2.stderr - testsuite/tests/typecheck/should_fail/FunDepOrigin1b.stderr - testsuite/tests/typecheck/should_fail/T13506.stderr - testsuite/tests/typecheck/should_fail/T15767.stderr - testsuite/tests/typecheck/should_fail/T19415.stderr - testsuite/tests/typecheck/should_fail/T19415b.stderr - testsuite/tests/typecheck/should_fail/T22924b.stderr - + testsuite/tests/typecheck/should_fail/T23162b.hs - + testsuite/tests/typecheck/should_fail/T23162b.stderr - + testsuite/tests/typecheck/should_fail/T23162c.hs - + testsuite/tests/typecheck/should_fail/T23162d.hs - testsuite/tests/typecheck/should_fail/T25325.stderr - testsuite/tests/typecheck/should_fail/T5236.stderr - testsuite/tests/typecheck/should_fail/T5246.stderr - testsuite/tests/typecheck/should_fail/T5978.stderr - testsuite/tests/typecheck/should_fail/T9612.stderr - testsuite/tests/typecheck/should_fail/TcCoercibleFail.stderr - testsuite/tests/typecheck/should_fail/all.T - testsuite/tests/typecheck/should_fail/tcfail143.stderr - utils/check-exact/ExactPrint.hs - utils/haddock/haddock-api/src/Haddock/Convert.hs The diff was not included because it is too large. View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/cbd234a7c56f5cfe1f0bf915788183… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/cbd234a7c56f5cfe1f0bf915788183… You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc] Pushed new branch wip/T26725
by Simon Peyton Jones (＠simonpj) 06 Jan '26

06 Jan '26

Simon Peyton Jones pushed new branch wip/T26725 at Glasgow Haskell Compiler / GHC -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/tree/wip/T26725 You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][master] Fix changelog formatting
by Marge Bot (＠marge-bot) 06 Jan '26

06 Jan '26

Marge Bot pushed to branch master at Glasgow Haskell Compiler / GHC Commits: 3d6aba77 by konsumlamm at 2026-01-06T09:33:16-05:00 Fix changelog formatting - - - - - 1 changed file: - libraries/base/changelog.md Changes: ===================================== libraries/base/changelog.md ===================================== @@ -747,7 +747,7 @@ * `Generic1`, as well as the associated datatypes and typeclasses in `GHC.Generics`, are now poly-kinded (#10604) - * `New modules `Data.Bifoldable` and `Data.Bitraversable` (previously defined + * New modules `Data.Bifoldable` and `Data.Bitraversable` (previously defined in the `bifunctors` package) (#10448) * `Data.Either` now provides `fromLeft` and `fromRight` (#12402) View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/3d6aba778f7628deef0141d9e8effc5… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/3d6aba778f7628deef0141d9e8effc5… You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][master] 5 commits: Improved fundeps for closed type families
by Marge Bot (＠marge-bot) 06 Jan '26

06 Jan '26

Marge Bot pushed to branch master at Glasgow Haskell Compiler / GHC Commits: 0b7df6db by Simon Peyton Jones at 2026-01-06T09:32:23-05:00 Improved fundeps for closed type families The big payload of this commit is to execute the plan suggested in #23162, by improving the way that we generate functional dependencies for closed type families. It is all described in Note [Exploiting closed type families] Most of the changes are in GHC.Tc.Solver.FunDeps Other small changes * GHC.Tc.Solver.bumpReductionDepth. This function brings together the code that * Bumps the depth * Checks for overflow Previously the two were separated, sometimes quite widely. * GHC.Core.Unify.niFixSubst: minor improvement, removing an unnecessary itraetion in the base case. * GHC.Core.Unify: no need to pass an InScopeSet to tcUnifyTysForInjectivity. It can calculate one for itself; and it is never inspected anyway so it's free to do so. * GHC.Tc.Errors.Ppr: slight impovement to the error message for reduction-stack overflow, when a constraint (rather than a type) is involved. * GHC.Tc.Solver.Monad.wrapUnifier: small change to the API - - - - - fde8bd88 by Simon Peyton Jones at 2026-01-06T09:32:23-05:00 Add missing (KK4) to kick-out criteria There was a missing case in kick-out that meant we could fail to solve an eminently-solvable constraint. See the new notes about (KK4) - - - - - 00082844 by Simon Peyton Jones at 2026-01-06T09:32:23-05:00 Some small refactorings of error reporting in the typechecker This is just a tidy-up commit. * Add ei_insoluble to ErrorItem, to cache insolubility. Small tidy-up. * Remove `is_ip` and `mkIPErr` from GHC.Tc.Errors; instead enhance mkDictErr to handle implicit parameters. Small refactor. - - - - - fe4cb252 by Simon Peyton Jones at 2026-01-06T09:32:24-05:00 Improve recording of insolubility for fundeps This commit addresses #22652, by recording when the fundeps for a constraint are definitely insoluble. That in turn improves the perspicacity of the pattern-match overlap checker. See Note [Insoluble fundeps] - - - - - df0ffaa5 by Simon Peyton Jones at 2026-01-06T09:32:24-05:00 Fix a buglet in niFixSubst The MR of which this is part failed an assertion check extendTvSubst because we extended the TvSubst with a CoVar. Boo. This tiny patch fixes it, and adds the regression test from #13882 that showed it up. - - - - - 69 changed files: - compiler/GHC/Core/FamInstEnv.hs - compiler/GHC/Core/TyCo/Subst.hs - compiler/GHC/Core/TyCon.hs - compiler/GHC/Core/Unify.hs - compiler/GHC/HsToCore/Monad.hs - compiler/GHC/Tc/Errors.hs - compiler/GHC/Tc/Errors/Ppr.hs - compiler/GHC/Tc/Errors/Types.hs - compiler/GHC/Tc/Gen/Splice.hs - compiler/GHC/Tc/Solver.hs - compiler/GHC/Tc/Solver/Default.hs - compiler/GHC/Tc/Solver/Dict.hs - compiler/GHC/Tc/Solver/Equality.hs - compiler/GHC/Tc/Solver/FunDeps.hs - compiler/GHC/Tc/Solver/InertSet.hs - compiler/GHC/Tc/Solver/Monad.hs - compiler/GHC/Tc/Solver/Rewrite.hs - compiler/GHC/Tc/Types/Constraint.hs - compiler/GHC/Tc/Types/CtLoc.hs - compiler/GHC/Tc/Utils/Monad.hs - compiler/GHC/Tc/Utils/Unify.hs - compiler/GHC/Types/TyThing.hs - docs/users_guide/9.16.1-notes.rst - linters/lint-codes/LintCodes/Static.hs - testsuite/tests/indexed-types/should_compile/CEqCanOccursCheck.hs - testsuite/tests/indexed-types/should_fail/T12522a.hs - testsuite/tests/indexed-types/should_fail/T26176.stderr - testsuite/tests/parser/should_fail/RecordDotSyntaxFail10.stderr - testsuite/tests/parser/should_fail/RecordDotSyntaxFail13.stderr - testsuite/tests/parser/should_fail/T20654a.stderr - testsuite/tests/pmcheck/should_compile/T15753c.hs - + testsuite/tests/pmcheck/should_compile/T15753c.stderr - testsuite/tests/pmcheck/should_compile/T15753d.hs - + testsuite/tests/pmcheck/should_compile/T15753d.stderr - + testsuite/tests/pmcheck/should_compile/T22652.hs - + testsuite/tests/pmcheck/should_compile/T22652a.hs - testsuite/tests/pmcheck/should_compile/all.T - + testsuite/tests/polykinds/T13882.hs - testsuite/tests/polykinds/all.T - testsuite/tests/quantified-constraints/T15316A.stderr - testsuite/tests/quantified-constraints/T17267.stderr - testsuite/tests/quantified-constraints/T17267a.stderr - testsuite/tests/quantified-constraints/T17267b.stderr - testsuite/tests/quantified-constraints/T17267c.stderr - testsuite/tests/quantified-constraints/T17267e.stderr - testsuite/tests/quantified-constraints/T17458.stderr - testsuite/tests/typecheck/should_compile/T16188.hs - testsuite/tests/typecheck/should_fail/ContextStack1.stderr - testsuite/tests/typecheck/should_fail/FD3.stderr - testsuite/tests/typecheck/should_fail/FDsFromGivens2.stderr - testsuite/tests/typecheck/should_fail/FunDepOrigin1b.stderr - testsuite/tests/typecheck/should_fail/T13506.stderr - testsuite/tests/typecheck/should_fail/T15767.stderr - testsuite/tests/typecheck/should_fail/T19415.stderr - testsuite/tests/typecheck/should_fail/T19415b.stderr - testsuite/tests/typecheck/should_fail/T22924b.stderr - + testsuite/tests/typecheck/should_fail/T23162b.hs - + testsuite/tests/typecheck/should_fail/T23162b.stderr - + testsuite/tests/typecheck/should_fail/T23162c.hs - + testsuite/tests/typecheck/should_fail/T23162d.hs - testsuite/tests/typecheck/should_fail/T25325.stderr - testsuite/tests/typecheck/should_fail/T5236.stderr - testsuite/tests/typecheck/should_fail/T5246.stderr - testsuite/tests/typecheck/should_fail/T5978.stderr - testsuite/tests/typecheck/should_fail/T9612.stderr - testsuite/tests/typecheck/should_fail/TcCoercibleFail.stderr - testsuite/tests/typecheck/should_fail/all.T - testsuite/tests/typecheck/should_fail/tcfail143.stderr - utils/haddock/haddock-api/src/Haddock/Convert.hs The diff was not included because it is too large. View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/8f2093363fd8a3b8386770c72aefa7… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/8f2093363fd8a3b8386770c72aefa7… You're receiving this email because of your account on gitlab.haskell.org.

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