December 2025 - ghc-commits

[Git][ghc/ghc][wip/int-index/imp-exp-wildcards] 21 commits: Quantify arg before mult in function arrows
by Vladislav Zavialov (＠int-index) 16 Dec '25

16 Dec '25

Vladislav Zavialov pushed to branch wip/int-index/imp-exp-wildcards at Glasgow Haskell Compiler / GHC Commits: ac0815d5 by sheaf at 2025-12-10T23:39:57-05:00 Quantify arg before mult in function arrows As noted in #23764, we expect quantification order to be left-to-right, so that in a type such as a %m -> b the inferred quantification order should be [a, m, b] and not [m, a, b]. This was addressed in commit d31fbf6c, but that commit failed to update some other functions such as GHC.Core.TyCo.FVs.tyCoFVsOfType. This affects Haddock, as whether we print an explicit forall or not depends on whether the inferred quantification order matches the actual quantification order. - - - - - 2caf796e by sheaf at 2025-12-10T23:39:57-05:00 Haddock: improvements to ty-var quantification This commit makes several improvements to how Haddock deals with the quantification of type variables: 1. In pattern synonyms, Haddock used to jumble up universal and existential quantification. That is now fixed, fixing #26252. Tested in the 'PatternSyns2' haddock-html test. 2. The logic for computing whether to use an explicit kind annotation for a type variable quantified in a forall was not even wrong. This commit improves the heuristic, but it will always remain an imperfect heuristic (lest we actually run kind inference again). In the future (#26271), we hope to avoid reliance on this heuristic. - - - - - b14bdd59 by Teo Camarasu at 2025-12-10T23:40:38-05:00 Add explicit export list to GHC.Num Let's make clear what this module exports to allow us to easily deprecate and remove some of these in the future. Resolves https://gitlab.haskell.org/ghc/ghc/-/issues/26625 - - - - - d99f8326 by Cheng Shao at 2025-12-11T19:14:18-05:00 compiler: remove unused CPP code in foreign stub This patch removes unused CPP code in the generated foreign stub: - `#define IN_STG_CODE 0` is not needed, since `Rts.h` already includes this definition - The `if defined(__cplusplus)` code paths are not needed in the `.c` file, since we don't generate C++ stubs and don't include C++ headers in our stubs. But it still needs to be present in the `.h` header since it might be later included into C++ source files. - - - - - 46c9746f by Cheng Shao at 2025-12-11T19:14:57-05:00 configure: bump LlvmMaxVersion to 22 This commit bumps LlvmMaxVersion to 22; 21.x releases have been available since Aug 26th, 2025 and there's no regressions with 21.x so far. This bump is also required for updating fedora image to 43. - - - - - 96fce8d0 by Cheng Shao at 2025-12-12T01:17:51+01:00 hadrian: add support for building with UndefinedBehaviorSanitizer This patch adds a +ubsan flavour transformer to hadrian to build all stage1+ C/C++ code with UndefinedBehaviorSanitizer. This is particularly useful to catch potential undefined behavior in the RTS codebase. - - - - - f7a06d8c by Cheng Shao at 2025-12-12T01:17:51+01:00 ci: update alpine/fedora & add ubsan job This patch updates alpine image to 3.23, fedora image to 43, and adds a `x86_64-linux-fedora43-validate+debug_info+ubsan` job that's run in validate/nightly pipelines to catch undefined behavior in the RTS codebase. - - - - - 2ccd11ca by Cheng Shao at 2025-12-12T01:17:51+01:00 rts: fix zero-length VLA undefined behavior in interpretBCO This commit fixes a zero-length VLA undefined behavior in interpretBCO, caught by UBSan: ``` +rts/Interpreter.c:3133:19: runtime variable length array bound evaluates to non-positive value 0 ``` - - - - - 4156ed19 by Cheng Shao at 2025-12-12T01:17:51+01:00 rts: fix unaligned ReadSpB in interpretBCO This commit fixes unaligned ReadSpB in interpretBCO, caught by UBSan: ``` +rts/Interpreter.c:2174:64: runtime load of misaligned address 0x004202059dd1 for type 'StgWord', which requires 8 byte alignment ``` To perform proper unaligned read, we define StgUnalignedWord as a type alias of StgWord with aligned(1) attribute, and load StgUnalignedWord instead of StgWord in ReadSpB, so the C compiler is aware that we're not loading with natural alignment. - - - - - fef89fb9 by Cheng Shao at 2025-12-12T01:17:51+01:00 rts: fix signed integer overflow in subword arithmetic in interpretBCO This commit fixes signed integer overflow in subword arithmetic in interpretBCO, see added note for detailed explanation. - - - - - 3c001377 by Cheng Shao at 2025-12-13T05:03:15-05:00 ci: use treeless fetch for perf notes This patch improves the ci logic for fetching perf notes by using treeless fetch (https://github.blog/open-source/git/get-up-to-speed-with-partial-clone-and-…) to avoid downloading all blobs of the perf notes repo at once, and only fetch the actually required blobs on-demand when needed. This makes the initial `test-metrics.sh pull` operation much faster, and also more robust, since we are seeing an increasing rate of 504 errors in CI when fetching all perf notes at once, which is a major source of CI flakiness at this point. Co-authored-by: Codex <codex(a)openai.com> - - - - - 123a8d77 by Peter Trommler at 2025-12-13T05:03:57-05:00 Cmm: remove restriction in MachOp folding - - - - - 0b54b5fd by Andreas Klebinger at 2025-12-13T05:04:38-05:00 Remove explicit Typeable deriviations. - - - - - 08b13f7b by Cheng Shao at 2025-12-13T05:05:18-05:00 ci: set gc.auto=0 during setup stage This patch sets `gc.auto=0` during `setup` stage of CI, see added comment for detailed explanation. - - - - - 3b5aecb5 by Ben Gamari at 2025-12-13T23:43:10+01:00 Bump exceptions submodule to 0.10.11 - - - - - c32de3b0 by Johan Förberg at 2025-12-15T02:36:03-05:00 base: Define Semigroup and Monoid instances for lazy ST CLC proposal: https://github.com/haskell/core-libraries-committee/issues/374 Fixes #26581 - - - - - 4f8b660c by mangoiv at 2025-12-15T02:37:05-05:00 ci: do not require nightly cabal-reinstall job to succeed - - - - - 2c2a3ef3 by Cheng Shao at 2025-12-15T11:51:53-05:00 docs: drop obsolete warning about -fexternal-interpreter on windows This patch drops an obsolete warning about -fexternal-interpreter not supported on windows; it is supported since a long time ago, including the profiled way. - - - - - 68573aa5 by Marc Scholten at 2025-12-15T11:53:00-05:00 haddock: Drop Haddock.Backends.HaddockDB as it's unused - - - - - 48b9f05d by Vladislav Zavialov at 2025-12-16T13:05:36+01:00 Parser: improve mkModuleImpExp, remove checkImportSpec 1. The `mkModuleImpExp` helper now knows whether it is processing an import or export list item, and uses this information to produce a more accurate error message for `import M (T(..,x))` with PatternSynonyms disabled. The old message incorrectly referred to this case as an export form. 2. The `checkImportSpec` helper is removed in favor of more comprehensive error checking in `mkModuleImpExp`. 3. Additionaly, the invariants of `ImpExpList` and `ImpExpAllWith` have been made more explicit in the comments and assertions (calls to 'panic'). Test case: import-syntax-no-ext - - - - - 6de81335 by Vladislav Zavialov at 2025-12-16T13:05:36+01:00 Subordinate namespace-specified wildcards (#25901) Add support for subordinate namespace-specified wildcards `X(type ..)` and `X(data ..)` to import and export lists. Examples: import M (Cls(type ..)) -- imports Cls and all its associated types import M (Cls(data ..)) -- imports Cls and all its methods module M (R(data ..), C(type ..)) where -- exports R and all its data constructors and record fields; -- exports C and all its associated types, but not its methods The scope of this change is limited to the case where the wildcard is the only subordinate import/export item, whereas the more complex forms `X(type .., f)` or `X(type .., data ..)` are unsupported and raise the newly introduced PsErrUnsupportedExplicitNamespace error. This restriction may be lifted later. Summary of the changes: 1. Refactor IEThingAll to store its extension field XIEThingAll as a record IEThingAllExt instead of a tuple. 2. Extend the AST by adding a NamespaceSpecifier field to IEThingAllExt, representing an optional namespace specifier `type` or `data` in front of a subordinate wildcard `X(..)`. 3. Extend the grammar in Parser.y with productions for `type ..` and `data ..` in subordinate import/export items. 4. Introduce `filterByNamespaceGREs` to filter [GlobalRdrElt] by a NamespaceSpecifier; use it in `filterImports` and `exports_from_avail` to account for the namespace specifier in IEThingAll. 5. Improve diagnostics by storing more information in DodgyImportsEmptyParent and DodgyExportsEmptyParent. Test cases: T25901_sub_e T25901_sub_f T25901_sub_g T25901_sub_a T25901_sub_b T25901_sub_c T25901_sub_d T25901_sub_w DodgyImports02 DodgyImports03 DodgyImports04 - - - - - 102 changed files: - .gitlab-ci.yml - .gitlab/ci.sh - .gitlab/generate-ci/gen_ci.hs - .gitlab/jobs.yaml - .gitlab/rel_eng/fetch-gitlab-artifacts/fetch_gitlab.py - .gitlab/rel_eng/mk-ghcup-metadata/mk_ghcup_metadata.py - .gitlab/test-metrics.sh - compiler/GHC/Cmm/Opt.hs - compiler/GHC/Core/TyCo/FVs.hs - compiler/GHC/Core/TyCo/Rep.hs - compiler/GHC/Driver/CodeOutput.hs - compiler/GHC/Hs/Decls.hs - compiler/GHC/Hs/ImpExp.hs - compiler/GHC/Hs/Instances.hs - compiler/GHC/Parser.y - compiler/GHC/Parser/Errors/Ppr.hs - compiler/GHC/Parser/Errors/Types.hs - compiler/GHC/Parser/PostProcess.hs - compiler/GHC/Rename/Names.hs - compiler/GHC/Tc/Errors/Ppr.hs - compiler/GHC/Tc/Errors/Types.hs - compiler/GHC/Tc/Gen/Export.hs - compiler/GHC/Tc/Utils/TcMType.hs - compiler/GHC/Tc/Utils/TcType.hs - compiler/GHC/Types/Error/Codes.hs - compiler/GHC/Types/Name/Reader.hs - configure.ac - docs/users_guide/ghci.rst - hadrian/doc/flavours.md - hadrian/src/Flavour.hs - hadrian/src/Hadrian/Haskell/Cabal/Type.hs - hadrian/src/Hadrian/Haskell/Hash.hs - hadrian/src/Hadrian/Oracles/ArgsHash.hs - hadrian/src/Hadrian/Oracles/Cabal/Type.hs - hadrian/src/Hadrian/Oracles/DirectoryContents.hs - hadrian/src/Hadrian/Oracles/Path.hs - hadrian/src/Hadrian/Oracles/TextFile.hs - hadrian/src/Hadrian/Utilities.hs - hadrian/src/Oracles/Flavour.hs - hadrian/src/Oracles/ModuleFiles.hs - libraries/base/changelog.md - libraries/base/src/GHC/Num.hs - libraries/exceptions - libraries/ghc-internal/src/GHC/Internal/Control/Monad/ST/Lazy/Imp.hs - + rts/.ubsan-suppressions - rts/Interpreter.c - rts/include/stg/Types.h - rts/rts.cabal - testsuite/driver/testglobals.py - testsuite/driver/testlib.py - testsuite/tests/haddock/should_compile_flag_haddock/T17544_kw.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/interface-stability/base-exports.stdout-ws-32 - testsuite/tests/patsyn/should_fail/all.T - + testsuite/tests/patsyn/should_fail/import-syntax-no-ext.hs - + testsuite/tests/patsyn/should_fail/import-syntax-no-ext.stderr - + testsuite/tests/rename/should_compile/T25901_sub_e.hs - + testsuite/tests/rename/should_compile/T25901_sub_f.hs - + testsuite/tests/rename/should_compile/T25901_sub_f.stderr - + testsuite/tests/rename/should_compile/T25901_sub_g.hs - + testsuite/tests/rename/should_compile/T25901_sub_g.stderr - + testsuite/tests/rename/should_compile/T25901_sub_g_helper.hs - testsuite/tests/rename/should_compile/all.T - testsuite/tests/rename/should_fail/T23570b.stderr - + testsuite/tests/rename/should_fail/T25901_sub_a.hs - + testsuite/tests/rename/should_fail/T25901_sub_a.stderr - + testsuite/tests/rename/should_fail/T25901_sub_b.hs - + testsuite/tests/rename/should_fail/T25901_sub_b.stderr - + testsuite/tests/rename/should_fail/T25901_sub_c.hs - + testsuite/tests/rename/should_fail/T25901_sub_c.stderr - + testsuite/tests/rename/should_fail/T25901_sub_c_helper.hs - + testsuite/tests/rename/should_fail/T25901_sub_d.hs - + testsuite/tests/rename/should_fail/T25901_sub_d.stderr - + testsuite/tests/rename/should_fail/T25901_sub_d_helper.hs - + testsuite/tests/rename/should_fail/T25901_sub_w.hs - + testsuite/tests/rename/should_fail/T25901_sub_w.stderr - testsuite/tests/rename/should_fail/all.T - testsuite/tests/warnings/should_compile/DodgyExports03.stderr - testsuite/tests/warnings/should_compile/DodgyImports.stderr - + testsuite/tests/warnings/should_compile/DodgyImports02.hs - + testsuite/tests/warnings/should_compile/DodgyImports02.stderr - + testsuite/tests/warnings/should_compile/DodgyImports03.hs - + testsuite/tests/warnings/should_compile/DodgyImports03.stderr - + testsuite/tests/warnings/should_compile/DodgyImports03_helper.hs - + testsuite/tests/warnings/should_compile/DodgyImports04.hs - + testsuite/tests/warnings/should_compile/DodgyImports04.stderr - testsuite/tests/warnings/should_compile/DodgyImports_hiding.stderr - testsuite/tests/warnings/should_compile/all.T - utils/check-exact/ExactPrint.hs - utils/haddock/haddock-api/haddock-api.cabal - − utils/haddock/haddock-api/src/Haddock/Backends/HaddockDB.hs - utils/haddock/haddock-api/src/Haddock/Convert.hs - utils/haddock/haddock-api/src/Haddock/GhcUtils.hs - utils/haddock/html-test/ref/Bug1050.html - utils/haddock/html-test/ref/LinearTypes.html - utils/haddock/html-test/ref/PatternSyns.html - + utils/haddock/html-test/ref/PatternSyns2.html - utils/haddock/html-test/ref/TypeOperators.html - + utils/haddock/html-test/src/PatternSyns2.hs - utils/haddock/latex-test/ref/LinearTypes/LinearTypes.tex The diff was not included because it is too large. View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/482084af37d8cffbddccf25de49f07… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/482084af37d8cffbddccf25de49f07… You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][wip/T23162-part2] 31 commits: ci: Try using multi repl in ghc-in-ghci test
by Simon Peyton Jones (＠simonpj) 16 Dec '25

16 Dec '25

Simon Peyton Jones pushed to branch wip/T23162-part2 at Glasgow Haskell Compiler / GHC Commits: 3bfe7aa2 by Matthew Pickering at 2025-12-07T12:18:57-05:00 ci: Try using multi repl in ghc-in-ghci test This should be quite a bit faster than the ./hadrian/ghci command as it doesn't properly build all the dependencies. - - - - - 2ef1601a by Rodrigo Mesquita at 2025-12-07T12:19:38-05:00 Stack.Decode: Don't error on bitmap size 0 A RET_BCO may have a bitmap with no payload. In that case, the bitmap = 0. One can observe this by using -ddump-bcos and interpreting ``` main = pure () ``` Observe, for instance, that the BCO for this main function has size 0: ``` ProtoBCO Main.main#0: \u [] break<main:Main,0>() GHC.Internal.Base.pure GHC.Internal.Base.$fApplicativeIO GHC.Internal.Tuple.() bitmap: 0 [] BRK_FUN <breakarray> main:Main 0 <cc> PACK () 0 PUSH_G GHC.Internal.Base.$fApplicativeIO PUSH_APPLY_PP PUSH_G GHC.Internal.Base.pure ENTER ``` Perhaps we never tried to decode a stack in which a BCO like this was present. However, for the debugger, we want to decode stacks of threads stopped at breakpoints, and these kind of BCOs do get on a stack under e.g. `stg_apply_interp_info` frames. See the accompanying test in the next commit for an example to trigger the bug this commit fixes. Fixes #26640 - - - - - 747153d2 by Rodrigo Mesquita at 2025-12-07T12:19:38-05:00 Add test for #26640 - - - - - d4b1e353 by Simon Hengel at 2025-12-10T00:00:02-05:00 Fix syntax error in gadt_syntax.rst - - - - - 91cc8be6 by Cheng Shao at 2025-12-10T00:00:43-05:00 ci: fix "ci.sh clean" to address frequent out of space error on windows runners This patch fixes the `ci.sh clean` logic to address frequent out of space error on windows runners; previously it didn't clean up the inplace mingw blobs, which is the largest source of space leak on windows runners. See added comment for detailed explanation. - - - - - fe2b79f4 by Recursion Ninja at 2025-12-10T08:34:18-05:00 Narrow before optimising MUL/DIV/REM into shifts The MUL/DIV/REM operations can be optimised into shifts when one of the operands is a constant power of 2. However, as literals in Cmm are stored as 'Integer', for this to be correct we first need to narrow the literal to the appropriate width before checking whether the literal is a power of 2. Fixes #25664 - - - - - 06c2349c by Recursion Ninja at 2025-12-10T08:34:58-05:00 Decouple 'Language.Haskell.Syntax.Type' from 'GHC.Utils.Panic' - Remove the *original* defintion of 'hsQTvExplicit' defined within 'Language.Haskell.Syntax.Type' - Redefine 'hsQTvExplicit' as 'hsq_explicit' specialized to 'GhcPass' exported by 'GHC.Utils.Panic' - Define 'hsQTvExplicitBinders' as 'hsq_explicit' specialized to 'DocNameI' exported by 'Haddock.GhcUtils'. - Replace all call sites of the original 'hsQTvExplicit' definition with either: 1. 'hsQTvExplicit' updated definition 2. 'hsQTvExplicitBinders' All call sites never entered the 'XLHsQTyVars' constructor branch, but a call to 'panic' existed on this code path because the type system was not strong enought to guarantee that the 'XLHsQTyVars' construction was impossible. These two specialized functions provide the type system with enough information to make that guarantee, and hence the dependancy on 'panic' can be removed. - - - - - ac0815d5 by sheaf at 2025-12-10T23:39:57-05:00 Quantify arg before mult in function arrows As noted in #23764, we expect quantification order to be left-to-right, so that in a type such as a %m -> b the inferred quantification order should be [a, m, b] and not [m, a, b]. This was addressed in commit d31fbf6c, but that commit failed to update some other functions such as GHC.Core.TyCo.FVs.tyCoFVsOfType. This affects Haddock, as whether we print an explicit forall or not depends on whether the inferred quantification order matches the actual quantification order. - - - - - 2caf796e by sheaf at 2025-12-10T23:39:57-05:00 Haddock: improvements to ty-var quantification This commit makes several improvements to how Haddock deals with the quantification of type variables: 1. In pattern synonyms, Haddock used to jumble up universal and existential quantification. That is now fixed, fixing #26252. Tested in the 'PatternSyns2' haddock-html test. 2. The logic for computing whether to use an explicit kind annotation for a type variable quantified in a forall was not even wrong. This commit improves the heuristic, but it will always remain an imperfect heuristic (lest we actually run kind inference again). In the future (#26271), we hope to avoid reliance on this heuristic. - - - - - b14bdd59 by Teo Camarasu at 2025-12-10T23:40:38-05:00 Add explicit export list to GHC.Num Let's make clear what this module exports to allow us to easily deprecate and remove some of these in the future. Resolves https://gitlab.haskell.org/ghc/ghc/-/issues/26625 - - - - - d99f8326 by Cheng Shao at 2025-12-11T19:14:18-05:00 compiler: remove unused CPP code in foreign stub This patch removes unused CPP code in the generated foreign stub: - `#define IN_STG_CODE 0` is not needed, since `Rts.h` already includes this definition - The `if defined(__cplusplus)` code paths are not needed in the `.c` file, since we don't generate C++ stubs and don't include C++ headers in our stubs. But it still needs to be present in the `.h` header since it might be later included into C++ source files. - - - - - 46c9746f by Cheng Shao at 2025-12-11T19:14:57-05:00 configure: bump LlvmMaxVersion to 22 This commit bumps LlvmMaxVersion to 22; 21.x releases have been available since Aug 26th, 2025 and there's no regressions with 21.x so far. This bump is also required for updating fedora image to 43. - - - - - 96fce8d0 by Cheng Shao at 2025-12-12T01:17:51+01:00 hadrian: add support for building with UndefinedBehaviorSanitizer This patch adds a +ubsan flavour transformer to hadrian to build all stage1+ C/C++ code with UndefinedBehaviorSanitizer. This is particularly useful to catch potential undefined behavior in the RTS codebase. - - - - - f7a06d8c by Cheng Shao at 2025-12-12T01:17:51+01:00 ci: update alpine/fedora & add ubsan job This patch updates alpine image to 3.23, fedora image to 43, and adds a `x86_64-linux-fedora43-validate+debug_info+ubsan` job that's run in validate/nightly pipelines to catch undefined behavior in the RTS codebase. - - - - - 2ccd11ca by Cheng Shao at 2025-12-12T01:17:51+01:00 rts: fix zero-length VLA undefined behavior in interpretBCO This commit fixes a zero-length VLA undefined behavior in interpretBCO, caught by UBSan: ``` +rts/Interpreter.c:3133:19: runtime variable length array bound evaluates to non-positive value 0 ``` - - - - - 4156ed19 by Cheng Shao at 2025-12-12T01:17:51+01:00 rts: fix unaligned ReadSpB in interpretBCO This commit fixes unaligned ReadSpB in interpretBCO, caught by UBSan: ``` +rts/Interpreter.c:2174:64: runtime load of misaligned address 0x004202059dd1 for type 'StgWord', which requires 8 byte alignment ``` To perform proper unaligned read, we define StgUnalignedWord as a type alias of StgWord with aligned(1) attribute, and load StgUnalignedWord instead of StgWord in ReadSpB, so the C compiler is aware that we're not loading with natural alignment. - - - - - fef89fb9 by Cheng Shao at 2025-12-12T01:17:51+01:00 rts: fix signed integer overflow in subword arithmetic in interpretBCO This commit fixes signed integer overflow in subword arithmetic in interpretBCO, see added note for detailed explanation. - - - - - 3c001377 by Cheng Shao at 2025-12-13T05:03:15-05:00 ci: use treeless fetch for perf notes This patch improves the ci logic for fetching perf notes by using treeless fetch (https://github.blog/open-source/git/get-up-to-speed-with-partial-clone-and-…) to avoid downloading all blobs of the perf notes repo at once, and only fetch the actually required blobs on-demand when needed. This makes the initial `test-metrics.sh pull` operation much faster, and also more robust, since we are seeing an increasing rate of 504 errors in CI when fetching all perf notes at once, which is a major source of CI flakiness at this point. Co-authored-by: Codex <codex(a)openai.com> - - - - - 123a8d77 by Peter Trommler at 2025-12-13T05:03:57-05:00 Cmm: remove restriction in MachOp folding - - - - - 0b54b5fd by Andreas Klebinger at 2025-12-13T05:04:38-05:00 Remove explicit Typeable deriviations. - - - - - 08b13f7b by Cheng Shao at 2025-12-13T05:05:18-05:00 ci: set gc.auto=0 during setup stage This patch sets `gc.auto=0` during `setup` stage of CI, see added comment for detailed explanation. - - - - - 3b5aecb5 by Ben Gamari at 2025-12-13T23:43:10+01:00 Bump exceptions submodule to 0.10.11 - - - - - c32de3b0 by Johan Förberg at 2025-12-15T02:36:03-05:00 base: Define Semigroup and Monoid instances for lazy ST CLC proposal: https://github.com/haskell/core-libraries-committee/issues/374 Fixes #26581 - - - - - 4f8b660c by mangoiv at 2025-12-15T02:37:05-05:00 ci: do not require nightly cabal-reinstall job to succeed - - - - - 2c2a3ef3 by Cheng Shao at 2025-12-15T11:51:53-05:00 docs: drop obsolete warning about -fexternal-interpreter on windows This patch drops an obsolete warning about -fexternal-interpreter not supported on windows; it is supported since a long time ago, including the profiled way. - - - - - 68573aa5 by Marc Scholten at 2025-12-15T11:53:00-05:00 haddock: Drop Haddock.Backends.HaddockDB as it's unused - - - - - 924df511 by Simon Peyton Jones at 2025-12-16T10:06:48+00:00 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 - - - - - 78ac1a6e by Simon Peyton Jones at 2025-12-16T10:06:48+00:00 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) - - - - - 94503ad4 by Simon Peyton Jones at 2025-12-16T10:06:48+00:00 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. - - - - - c6122dfc by Simon Peyton Jones at 2025-12-16T10:06:48+00:00 Better fundeps for type-family Givens 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] - - - - - 44aea088 by Simon Peyton Jones at 2025-12-16T10:06:48+00:00 Error message wibbles - - - - - 113 changed files: - .gitlab-ci.yml - .gitlab/ci.sh - .gitlab/generate-ci/gen_ci.hs - .gitlab/jobs.yaml - .gitlab/rel_eng/fetch-gitlab-artifacts/fetch_gitlab.py - .gitlab/rel_eng/mk-ghcup-metadata/mk_ghcup_metadata.py - .gitlab/test-metrics.sh - compiler/GHC/Cmm/Opt.hs - compiler/GHC/Core/FamInstEnv.hs - compiler/GHC/Core/TyCo/FVs.hs - compiler/GHC/Core/TyCo/Rep.hs - compiler/GHC/Core/TyCon.hs - compiler/GHC/Core/Unify.hs - compiler/GHC/Driver/CodeOutput.hs - compiler/GHC/Hs/Type.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/TcMType.hs - compiler/GHC/Tc/Utils/TcType.hs - compiler/GHC/Tc/Utils/Unify.hs - compiler/GHC/Types/TyThing.hs - compiler/Language/Haskell/Syntax/Type.hs - configure.ac - docs/users_guide/exts/gadt_syntax.rst - docs/users_guide/ghci.rst - hadrian/doc/flavours.md - hadrian/src/Flavour.hs - hadrian/src/Hadrian/Haskell/Cabal/Type.hs - hadrian/src/Hadrian/Haskell/Hash.hs - hadrian/src/Hadrian/Oracles/ArgsHash.hs - hadrian/src/Hadrian/Oracles/Cabal/Type.hs - hadrian/src/Hadrian/Oracles/DirectoryContents.hs - hadrian/src/Hadrian/Oracles/Path.hs - hadrian/src/Hadrian/Oracles/TextFile.hs - hadrian/src/Hadrian/Utilities.hs - hadrian/src/Oracles/Flavour.hs - hadrian/src/Oracles/ModuleFiles.hs - libraries/base/changelog.md - libraries/base/src/GHC/Num.hs - libraries/exceptions - libraries/ghc-internal/src/GHC/Internal/Control/Monad/ST/Lazy/Imp.hs - libraries/ghc-internal/src/GHC/Internal/Stack/Decode.hs - linters/lint-codes/LintCodes/Static.hs - + rts/.ubsan-suppressions - rts/Interpreter.c - rts/include/stg/Types.h - rts/rts.cabal - testsuite/driver/testglobals.py - testsuite/driver/testlib.py - + testsuite/tests/bytecode/T26640.hs - + testsuite/tests/bytecode/T26640.script - + testsuite/tests/bytecode/T26640.stdout - testsuite/tests/bytecode/all.T - + testsuite/tests/cmm/opt/T25664.hs - + testsuite/tests/cmm/opt/T25664.stdout - testsuite/tests/cmm/opt/all.T - 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/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/interface-stability/base-exports.stdout-ws-32 - testsuite/tests/pmcheck/should_compile/T15753c.hs - + testsuite/tests/pmcheck/should_compile/T22652.hs - testsuite/tests/pmcheck/should_compile/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/FunDepOrigin1b.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/TcCoercibleFail.stderr - testsuite/tests/typecheck/should_fail/all.T - utils/haddock/haddock-api/haddock-api.cabal - − utils/haddock/haddock-api/src/Haddock/Backends/HaddockDB.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/html-test/ref/Bug1050.html - utils/haddock/html-test/ref/LinearTypes.html - utils/haddock/html-test/ref/PatternSyns.html - + utils/haddock/html-test/ref/PatternSyns2.html - utils/haddock/html-test/ref/TypeOperators.html - + utils/haddock/html-test/src/PatternSyns2.hs - utils/haddock/latex-test/ref/LinearTypes/LinearTypes.tex The diff was not included because it is too large. View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/bfff257ca6d35572eec23ae84a8cb8… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/bfff257ca6d35572eec23ae84a8cb8… You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][wip/spj-try-opt-coercion] 3 commits: Add better case merging
by Simon Peyton Jones (＠simonpj) 16 Dec '25

16 Dec '25

Simon Peyton Jones pushed to branch wip/spj-try-opt-coercion at Glasgow Haskell Compiler / GHC Commits: 88657af0 by Simon Peyton Jones at 2025-12-16T09:11:10+00:00 Add better case merging - - - - - 395e1128 by Simon Peyton Jones at 2025-12-16T09:11:28+00:00 Flip the sense of BinderSwapDecision It was weird before, which led to a bug in my new patch - - - - - f4ca153a by Simon Peyton Jones at 2025-12-16T09:37:31+00:00 Do isReflexiveCo in the Simplifier - - - - - 6 changed files: - compiler/GHC/Core/Coercion.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/Utils.hs Changes: ===================================== compiler/GHC/Core/Coercion.hs ===================================== @@ -709,7 +709,10 @@ isReflCo_maybe _ = Nothing -- | Slowly checks if the coercion is reflexive. Don't call this in a loop, -- as it walks over the entire coercion. isReflexiveCo :: Coercion -> Bool -isReflexiveCo = isJust . isReflexiveCo_maybe +isReflexiveCo (Refl {}) = True +isReflexiveCo (GRefl _ _ mco) = isReflKindMCo mco +isReflexiveCo (SymCo co) = isReflexiveCo co +isReflexiveCo co = coercionLKind co `eqType` coercionRKind co isReflexiveMCo :: MCoercion -> Bool isReflexiveMCo MRefl = True ===================================== compiler/GHC/Core/Opt/OccurAnal.hs ===================================== @@ -28,7 +28,7 @@ core expression with (hopefully) improved usage information. module GHC.Core.Opt.OccurAnal ( occurAnalysePgm, occurAnalyseExpr, - zapLambdaBndrs, BinderSwapDecision(..), scrutOkForBinderSwap + zapLambdaBndrs ) where import GHC.Prelude hiding ( head, init, last, tail ) @@ -36,7 +36,7 @@ import GHC.Prelude hiding ( head, init, last, tail ) import GHC.Core import GHC.Core.FVs import GHC.Core.Utils ( exprIsTrivial, isDefaultAlt, isExpandableApp, - mkCastMCo, mkTicks ) + mkCastMCo, mkTicks, BinderSwapDecision(..), scrutOkForBinderSwap ) import GHC.Core.Opt.Arity ( joinRhsArity, isOneShotBndr ) import GHC.Core.Coercion import GHC.Core.Type @@ -3535,6 +3535,7 @@ doesn't use it. So this is only to satisfy the perhaps-over-picky Lint. -} addBndrSwap :: OutExpr -> Id -> OccEnv -> OccEnv +-- See Note [Binder swap] -- See Note [The binder-swap substitution] addBndrSwap scrut case_bndr env@(OccEnv { occ_bs_env = swap_env, occ_bs_rng = rng_vars }) @@ -3542,7 +3543,7 @@ addBndrSwap scrut case_bndr , scrut_var /= case_bndr -- Consider: case x of x { ... } -- Do not add [x :-> x] to occ_bs_env, else lookupBndrSwap will loop - = env { occ_bs_env = extendVarEnv swap_env scrut_var (case_bndr', mco) + = env { occ_bs_env = extendVarEnv swap_env scrut_var (case_bndr', mkSymMCo mco) , occ_bs_rng = rng_vars `extendVarSet` case_bndr' `unionVarSet` tyCoVarsOfMCo mco } @@ -3552,27 +3553,6 @@ addBndrSwap scrut case_bndr case_bndr' = zapIdOccInfo case_bndr -- See Note [Zap case binders in proxy bindings] --- | See bBinderSwaOk. -data BinderSwapDecision - = NoBinderSwap - | DoBinderSwap OutVar MCoercion - -scrutOkForBinderSwap :: OutExpr -> BinderSwapDecision --- If (scrutOkForBinderSwap e = DoBinderSwap v mco, then --- v = e |> mco --- See Note [Case of cast] --- See Historical Note [Care with binder-swap on dictionaries] --- --- We use this same function in SpecConstr, and Simplify.Iteration, --- when something binder-swap-like is happening -scrutOkForBinderSwap e - = case e of - Tick _ e -> scrutOkForBinderSwap e -- Drop ticks - Var v -> DoBinderSwap v MRefl - Cast (Var v) co -> DoBinderSwap v (MCo (mkSymCo co)) - -- Cast: see Note [Case of cast] - _ -> NoBinderSwap - lookupBndrSwap :: OccEnv -> Id -> (CoreExpr, Id) -- See Note [The binder-swap substitution] -- Returns an expression of the same type as Id ===================================== compiler/GHC/Core/Opt/Simplify/Iteration.hs ===================================== @@ -22,7 +22,7 @@ import GHC.Core.TyCo.Compare( eqType ) import GHC.Core.Opt.Simplify.Env import GHC.Core.Opt.Simplify.Inline import GHC.Core.Opt.Simplify.Utils -import GHC.Core.Opt.OccurAnal ( occurAnalyseExpr, zapLambdaBndrs, scrutOkForBinderSwap, BinderSwapDecision (..) ) +import GHC.Core.Opt.OccurAnal ( occurAnalyseExpr, zapLambdaBndrs ) import GHC.Core.Make ( FloatBind, mkImpossibleExpr, castBottomExpr ) import qualified GHC.Core.Make import GHC.Core.Coercion hiding ( substCo, substCoVar ) @@ -1531,7 +1531,8 @@ rebuild_go env expr cont Stop {} -> return (emptyFloats env, expr) TickIt t cont -> rebuild_go env (mkTick t expr) cont CastIt { sc_co = co, sc_opt = opt, sc_cont = cont } - -> rebuild_go env (mkCast expr co') cont + | isReflexiveCo co -> rebuild_go env expr cont + | otherwise -> rebuild_go env (mkCast expr co') cont -- NB: mkCast implements the (Coercion co |> g) optimisation where co' = optOutCoercion env co opt @@ -3593,11 +3594,13 @@ addAltUnfoldings env case_bndr bndr_swap con_app env1 = addBinderUnfolding env case_bndr con_app_unf -- See Note [Add unfolding for scrutinee] + -- e.g. case (x |> co) of K a b -> blah + -- We add to `x` the unfolding (K a b |> sym co) env2 | DoBinderSwap v mco <- bndr_swap = addBinderUnfolding env1 v $ if isReflMCo mco -- isReflMCo: avoid calling mk_simple_unf then con_app_unf -- twice in the common case - else mk_simple_unf (mkCastMCo con_app mco) + else mk_simple_unf (mkCastMCo con_app (mkSymMCo mco)) | otherwise = env1 ===================================== compiler/GHC/Core/Opt/Simplify/Utils.hs ===================================== @@ -2693,7 +2693,7 @@ mkCase, mkCase1, mkCase2, mkCase3 mkCase mode scrut outer_bndr alts_ty alts | sm_case_merge mode - , Just (joins, alts') <- mergeCaseAlts outer_bndr alts + , Just (joins, alts') <- mergeCaseAlts scrut outer_bndr alts = do { tick (CaseMerge outer_bndr) ; case_expr <- mkCase1 mode scrut outer_bndr alts_ty alts' ; return (mkLets joins case_expr) } ===================================== compiler/GHC/Core/Opt/SpecConstr.hs ===================================== @@ -30,7 +30,6 @@ import GHC.Core.Opt.Simplify.Inline import GHC.Core.FVs ( exprsFreeVarsList, exprFreeVars ) import GHC.Core.Opt.Monad import GHC.Core.Opt.WorkWrap.Utils -import GHC.Core.Opt.OccurAnal( BinderSwapDecision(..), scrutOkForBinderSwap ) import GHC.Core.DataCon import GHC.Core.Class( classTyVars ) import GHC.Core.Coercion hiding( substCo ) @@ -2025,9 +2024,9 @@ spec_one env fn arg_bndrs body (call_pat, rule_number) -- , text "spec_call_args" <+> ppr spec_call_args -- , text "rule_rhs" <+> ppr rule_rhs -- , text "adds_void_worker_arg" <+> ppr add_void_arg ----- , text "body" <+> ppr body ----- , text "spec_rhs" <+> ppr spec_rhs ----- , text "how_bound" <+> ppr (sc_how_bound env) ] +-- , text "body" <+> ppr body +-- , text "spec_rhs" <+> ppr spec_rhs +-- , text "how_bound" <+> ppr (sc_how_bound env) ] -- ] ; return (spec_usg, OS { os_pat = call_pat, os_rule = rule , os_id = spec_id ===================================== compiler/GHC/Core/Utils.hs ===================================== @@ -19,6 +19,7 @@ module GHC.Core.Utils ( mergeAlts, mergeCaseAlts, trimConArgs, filterAlts, combineIdenticalAlts, refineDefaultAlt, scaleAltsBy, + BinderSwapDecision(..), scrutOkForBinderSwap, -- * Properties of expressions exprType, coreAltType, coreAltsType, @@ -116,7 +117,6 @@ import Data.ByteString ( ByteString ) import Data.Function ( on ) import Data.List ( sort, sortBy, partition, zipWith4, mapAccumL ) import Data.Ord ( comparing ) -import Control.Monad ( guard ) import qualified Data.Set as Set {- @@ -590,6 +590,28 @@ The default alternative must be first, if it exists at all. This makes it easy to find, though it makes matching marginally harder. -} +data BinderSwapDecision + = NoBinderSwap + | DoBinderSwap OutVar MCoercion + +scrutOkForBinderSwap :: OutExpr -> BinderSwapDecision +-- If (scrutOkForBinderSwap e = DoBinderSwap v mco, then +-- e = v |> mco +-- See Note [Case of cast] +-- See Historical Note [Care with binder-swap on dictionaries] +-- +-- We use this same function in SpecConstr, and Simplify.Iteration, +-- when something binder-swap-like is happening +-- +-- See Note [Binder swap] in GHC.Core.Opt.OccurAnal +scrutOkForBinderSwap e + = case e of + Tick _ e -> scrutOkForBinderSwap e -- Drop ticks + Var v -> DoBinderSwap v MRefl + Cast (Var v) co -> DoBinderSwap v (MCo co) + -- Cast: see Note [Case of cast] + _ -> NoBinderSwap + -- | Extract the default case alternative findDefault :: [Alt b] -> ([Alt b], Maybe (Expr b)) findDefault (Alt DEFAULT args rhs : alts) = assert (null args) (alts, Just rhs) @@ -651,9 +673,9 @@ filters down the matching alternatives in GHC.Core.Opt.Simplify.rebuildCase. -} --------------------------------- -mergeCaseAlts :: Id -> [CoreAlt] -> Maybe ([CoreBind], [CoreAlt]) +mergeCaseAlts :: CoreExpr -> Id -> [CoreAlt] -> Maybe ([CoreBind], [CoreAlt]) -- See Note [Merge Nested Cases] -mergeCaseAlts outer_bndr (Alt DEFAULT _ deflt_rhs : outer_alts) +mergeCaseAlts scrut outer_bndr (Alt DEFAULT _ deflt_rhs : outer_alts) | Just (joins, inner_alts) <- go deflt_rhs = Just (joins, mergeAlts outer_alts inner_alts) -- NB: mergeAlts gives priority to the left @@ -665,6 +687,9 @@ mergeCaseAlts outer_bndr (Alt DEFAULT _ deflt_rhs : outer_alts) -- When we merge, we must ensure that e1 takes -- precedence over e2 as the value for A! where + bndr_swap :: BinderSwapDecision + bndr_swap = scrutOkForBinderSwap scrut + go :: CoreExpr -> Maybe ([CoreBind], [CoreAlt]) -- Whizzo: we can merge! @@ -702,11 +727,10 @@ mergeCaseAlts outer_bndr (Alt DEFAULT _ deflt_rhs : outer_alts) = do { (joins, alts) <- go body -- Check for capture; but only if we could otherwise do a merge - ; let capture = outer_bndr `elem` bindersOf bind - || outer_bndr `elemVarSet` bindFreeVars bind - ; guard (not capture) + -- (i.e. the recursive `go` succeeds) + ; fix_up_binds <- okToFloatJoin bndr_swap outer_bndr bind - ; return (bind:joins, alts ) } + ; return (fix_up_binds ++ (bind : joins), alts ) } | otherwise = Nothing @@ -718,7 +742,25 @@ mergeCaseAlts outer_bndr (Alt DEFAULT _ deflt_rhs : outer_alts) go _ = Nothing -mergeCaseAlts _ _ = Nothing +mergeCaseAlts _ _ _ = Nothing + +okToFloatJoin :: BinderSwapDecision -> Id -> CoreBind -> Maybe [CoreBind] +-- Check a join-point binding to see if it can be floated out of +-- the DEFAULT branch of a `case`. A Just result means "yes", +-- and the [CoreBInd] are the extra fix-up bindings to add. +-- See Note [Floating join points out of DEFAULT alternatives] +okToFloatJoin bndr_swap outer_bndr bind + | outer_bndr `elem` bindersOf bind -- (a) + = Nothing + | outer_bndr `elemVarSet` bindFreeVars bind -- (b) + = case bndr_swap of + DoBinderSwap scrut_var mco + | scrut_var /= outer_bndr + -> Just [ NonRec outer_bndr (mkCastMCo (Var scrut_var) mco) ] + _ -> Nothing + | otherwise + = Just [] + --------------------------------- mergeAlts :: [Alt a] -> [Alt a] -> [Alt a] @@ -927,10 +969,43 @@ Wrinkles non-join-points unless the /outer/ case has just one alternative; doing so would risk more allocation + Floating out join points isn't entirely straightforward. + See Note [Floating join points out of DEFAULT alternatives] + (MC5) See Note [Cascading case merge] See also Note [Example of case-merging and caseRules] in GHC.Core.Opt.Simplify.Utils +Note [Floating join points out of DEFAULT alternatives] +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +Consider this, from (MC4) of Note [Merge Nested Cases] + case x of r + DEFAULT -> join j = rhs in case r of ... + alts + +We want to float that join point out to give this + join j = rhs + case x of r + DEFAULT -> case r of ... + alts + +But doing so is flat-out wrong if the scoping gets messed up: + (a) case x of r { DEFAULT -> join r = ... in ...r... } + (b) case x of r { DEFAULT -> join j = ...r.. in ... } +In both cases we can't float the join point out because r changes its meaning. + +BUT we can fix up case (b) by adding an extra binding, like this + let r = x in + join j = rhs[r] + case x of r + DEFAULT -> ...r... + ...other alts... + +This extra binding is figured out by `okToFloatJoin`. + +Note that the cases that still don't work (e.g. (a)) will probably work fine the +next iteration of the Simplifier, because they involve shadowing, and the Simplifier +generally eliminates shadowing. Note [Cascading case merge] ~~~~~~~~~~~~~~~~~~~~~~~~~~~ View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/52dbcf4b15f9dddd06931bae45ee5c… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/52dbcf4b15f9dddd06931bae45ee5c… You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][wip/int-index/imp-exp-wildcards] 2 commits: Parser: improve mkModuleImpExp, remove checkImportSpec
by Vladislav Zavialov (＠int-index) 16 Dec '25

16 Dec '25

Vladislav Zavialov pushed to branch wip/int-index/imp-exp-wildcards at Glasgow Haskell Compiler / GHC Commits: aa28afc8 by Vladislav Zavialov at 2025-12-16T00:33:13+01:00 Parser: improve mkModuleImpExp, remove checkImportSpec 1. The `mkModuleImpExp` helper now knows whether it is processing an import or export list item, and uses this information to produce a more accurate error message for `import M (T(..,x))` with PatternSynonyms disabled. The old message incorrectly referred to this case as an export form. 2. The `checkImportSpec` helper is removed in favor of more comprehensive error checking in `mkModuleImpExp`. 3. Additionaly, the invariants of `ImpExpList` and `ImpExpAllWith` have been made more explicit in the comments and assertions (calls to 'panic'). Test case: import-syntax-no-ext - - - - - 482084af by Vladislav Zavialov at 2025-12-16T00:34:09+01:00 Subordinate namespace-specified wildcards Add support for subordinate namespace-specified wildcards `X(type ..)` and `X(data ..)` to import and export lists. Examples: import M (Cls(type ..)) -- imports Cls and all its associated types import M (Cls(data ..)) -- imports Cls and all its methods module M (R(data ..), C(type ..)) where -- exports R and all its data constructors and record fields; -- exports C and all its associated types, but not its methods The scope of this change is limited to the case where the wildcard is the only subordinate import/export item, whereas the more complex forms `X(type .., f)` or `X(type .., data ..)` are unsupported and raise the newly introduced PsErrUnsupportedExplicitNamespace error. This restriction may be lifted later. Summary of the changes: 1. Refactor IEThingAll to store its extension field XIEThingAll as a record IEThingAllExt instead of a tuple. 2. Extend the AST by adding a NamespaceSpecifier field to IEThingAllExt, representing an optional namespace specifier `type` or `data` in front of a subordinate wildcard `X(..)`. 3. Extend the grammar in Parser.y with productions for `type ..` and `data ..` in subordinate import/export items. 4. Introduce `filterByNamespaceGREs` to filter [GlobalRdrElt] by a NamespaceSpecifier; use it in `filterImports` and `exports_from_avail` to account for the namespace specifier in IEThingAll. 5. Improve diagnostics by storing more information in DodgyImportsEmptyParent and DodgyExportsEmptyParent. Test cases: T25901_sub_e T25901_sub_f T25901_sub_g T25901_sub_a T25901_sub_b T25901_sub_c T25901_sub_d T25901_sub_w DodgyImports02 DodgyImports03 DodgyImports04 - - - - - 50 changed files: - compiler/GHC/Hs/Decls.hs - compiler/GHC/Hs/ImpExp.hs - compiler/GHC/Hs/Instances.hs - compiler/GHC/Parser.y - compiler/GHC/Parser/Errors/Ppr.hs - compiler/GHC/Parser/Errors/Types.hs - compiler/GHC/Parser/PostProcess.hs - compiler/GHC/Rename/Names.hs - compiler/GHC/Tc/Errors/Ppr.hs - compiler/GHC/Tc/Errors/Types.hs - compiler/GHC/Tc/Gen/Export.hs - compiler/GHC/Types/Error/Codes.hs - compiler/GHC/Types/Name/Reader.hs - testsuite/tests/haddock/should_compile_flag_haddock/T17544_kw.stderr - testsuite/tests/patsyn/should_fail/all.T - + testsuite/tests/patsyn/should_fail/import-syntax-no-ext.hs - + testsuite/tests/patsyn/should_fail/import-syntax-no-ext.stderr - + testsuite/tests/rename/should_compile/T25901_sub_e.hs - + testsuite/tests/rename/should_compile/T25901_sub_f.hs - + testsuite/tests/rename/should_compile/T25901_sub_f.stderr - + testsuite/tests/rename/should_compile/T25901_sub_g.hs - + testsuite/tests/rename/should_compile/T25901_sub_g.stderr - + testsuite/tests/rename/should_compile/T25901_sub_g_helper.hs - testsuite/tests/rename/should_compile/all.T - testsuite/tests/rename/should_fail/T23570b.stderr - + testsuite/tests/rename/should_fail/T25901_sub_a.hs - + testsuite/tests/rename/should_fail/T25901_sub_a.stderr - + testsuite/tests/rename/should_fail/T25901_sub_b.hs - + testsuite/tests/rename/should_fail/T25901_sub_b.stderr - + testsuite/tests/rename/should_fail/T25901_sub_c.hs - + testsuite/tests/rename/should_fail/T25901_sub_c.stderr - + testsuite/tests/rename/should_fail/T25901_sub_c_helper.hs - + testsuite/tests/rename/should_fail/T25901_sub_d.hs - + testsuite/tests/rename/should_fail/T25901_sub_d.stderr - + testsuite/tests/rename/should_fail/T25901_sub_d_helper.hs - + testsuite/tests/rename/should_fail/T25901_sub_w.hs - + testsuite/tests/rename/should_fail/T25901_sub_w.stderr - testsuite/tests/rename/should_fail/all.T - testsuite/tests/warnings/should_compile/DodgyExports03.stderr - testsuite/tests/warnings/should_compile/DodgyImports.stderr - + testsuite/tests/warnings/should_compile/DodgyImports02.hs - + testsuite/tests/warnings/should_compile/DodgyImports02.stderr - + testsuite/tests/warnings/should_compile/DodgyImports03.hs - + testsuite/tests/warnings/should_compile/DodgyImports03.stderr - + testsuite/tests/warnings/should_compile/DodgyImports03_helper.hs - + testsuite/tests/warnings/should_compile/DodgyImports04.hs - + testsuite/tests/warnings/should_compile/DodgyImports04.stderr - testsuite/tests/warnings/should_compile/DodgyImports_hiding.stderr - testsuite/tests/warnings/should_compile/all.T - utils/check-exact/ExactPrint.hs The diff was not included because it is too large. View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/49888ab8714b849cddb5f48e36c855… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/49888ab8714b849cddb5f48e36c855… You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc] Pushed new branch wip/jeltsch/known-key-removals/generics
by Wolfgang Jeltsch (＠jeltsch) 16 Dec '25

16 Dec '25

Wolfgang Jeltsch pushed new branch wip/jeltsch/known-key-removals/generics at Glasgow Haskell Compiler / GHC -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/tree/wip/jeltsch/known-key-removals/ge… You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][master] haddock: Drop Haddock.Backends.HaddockDB as it's unused
by Marge Bot (＠marge-bot) 15 Dec '25

15 Dec '25

Marge Bot pushed to branch master at Glasgow Haskell Compiler / GHC Commits: 68573aa5 by Marc Scholten at 2025-12-15T11:53:00-05:00 haddock: Drop Haddock.Backends.HaddockDB as it's unused - - - - - 2 changed files: - utils/haddock/haddock-api/haddock-api.cabal - − utils/haddock/haddock-api/src/Haddock/Backends/HaddockDB.hs Changes: ===================================== utils/haddock/haddock-api/haddock-api.cabal ===================================== @@ -139,7 +139,6 @@ library Haddock.Backends.Xhtml.Types Haddock.Backends.Xhtml.Utils Haddock.Backends.LaTeX - Haddock.Backends.HaddockDB Haddock.Backends.Hoogle Haddock.Backends.Hyperlinker Haddock.Backends.Hyperlinker.Parser ===================================== utils/haddock/haddock-api/src/Haddock/Backends/HaddockDB.hs deleted ===================================== @@ -1,178 +0,0 @@ ------------------------------------------------------------------------------ - ------------------------------------------------------------------------------ - --- | --- Module : Haddock.Backends.HaddockDB --- Copyright : (c) Simon Marlow 2003 --- License : BSD-like --- --- Maintainer : haddock(a)projects.haskell.org --- Stability : experimental --- Portability : portable -module Haddock.Backends.HaddockDB (ppDocBook) where - -{- -import HaddockTypes -import HaddockUtil -import HsSyn2 - -import Text.PrettyPrint --} - ------------------------------------------------------------------------------ --- Printing the results in DocBook format - -ppDocBook :: a -ppDocBook = error "not working" - -{- -ppDocBook :: FilePath -> [(Module, Interface)] -> String -ppDocBook odir mods = render (ppIfaces mods) - -ppIfaces mods - = text "<!DOCTYPE BOOK PUBLIC \"-//OASIS//DTD DocBook V3.1//EN\" [" - $$ text "]>" - $$ text "<book>" - $$ text "<bookinfo>" - $$ text "<author><othername>HaskellDoc version 0.0</othername></author>" - $$ text "</bookinfo>" - $$ text "<article>" - $$ vcat (map do_mod mods) - $$ text "</article></book>" - where - do_mod (Module mod, iface) - = text "<sect1 id=\"sec-" <> text mod <> text "\">" - $$ text "<title><literal>" - <> text mod - <> text "</literal></title>" - $$ text "<indexterm><primary><literal>" - <> text mod - <> text "</literal></primary></indexterm>" - $$ text "<variablelist>" - $$ vcat (map (do_export mod) (eltsFM (iface_decls iface))) - $$ text "</variablelist>" - $$ text "</sect1>" - - do_export mod decl | (nm:_) <- declBinders decl - = text "<varlistentry id=" <> ppLinkId mod nm <> char '>' - $$ text "<term><literal>" - <> do_decl decl - <> text "</literal></term>" - $$ text "<listitem>" - $$ text "<para>" - $$ text "</para>" - $$ text "</listitem>" - $$ text "</varlistentry>" - do_export _ _ = empty - - do_decl (HsTypeSig _ [nm] ty _) - = ppHsName nm <> text " :: " <> ppHsType ty - do_decl (HsTypeDecl _ nm args ty _) - = hsep ([text "type", ppHsName nm ] - ++ map ppHsName args - ++ [equals, ppHsType ty]) - do_decl (HsNewTypeDecl loc ctx nm args con drv _) - = hsep ([text "data", ppHsName nm] -- data, not newtype - ++ map ppHsName args - ) <+> equals <+> ppHsConstr con -- ToDo: derivings - do_decl (HsDataDecl loc ctx nm args cons drv _) - = hsep ([text "data", {-ToDo: context-}ppHsName nm] - ++ map ppHsName args) - <+> vcat (zipWith (<+>) (equals : repeat (char '|')) - (map ppHsConstr cons)) - do_decl (HsClassDecl loc ty fds decl _) - = hsep [text "class", ppHsType ty] - do_decl decl - = empty - -ppHsConstr :: HsConDecl -> Doc -ppHsConstr (HsRecDecl pos name tvs ctxt fieldList maybe_doc) = - ppHsName name - <> (braces . hsep . punctuate comma . map ppField $ fieldList) -ppHsConstr (HsConDecl pos name tvs ctxt typeList maybe_doc) = - hsep (ppHsName name : map ppHsBangType typeList) - -ppField (HsFieldDecl ns ty doc) - = hsep (punctuate comma (map ppHsName ns) ++ - [text "::", ppHsBangType ty]) - -ppHsBangType :: HsBangType -> Doc -ppHsBangType (HsBangedTy ty) = char '!' <> ppHsType ty -ppHsBangType (HsUnBangedTy ty) = ppHsType ty - -ppHsContext :: HsContext -> Doc -ppHsContext [] = empty -ppHsContext context = parenList (map (\ (a,b) -> ppHsQName a <+> - hsep (map ppHsAType b)) context) - -ppHsType :: HsType -> Doc -ppHsType (HsForAllType _ Nothing context htype) = - hsep [ ppHsContext context, text "=>", ppHsType htype] -ppHsType (HsForAllType fvf (Just tvs) [] htype) = - hsep (text "forall" : map ppHsName tvs ++ pprHsForAllSeparator fvf : - [ppHsType htype]) -ppHsType (HsForAllType fvf (Just tvs) context htype) = - hsep (text "forall" : map ppHsName tvs ++ pprHsForAllSeparator fvf : - ppHsContext context : text "=>" : [ppHsType htype]) -ppHsType (HsTyFun a b) = fsep [ppHsBType a, text "->", ppHsType b] -ppHsType (HsTyIP n t) = fsep [(char '?' <> ppHsName n), text "::", ppHsType t] -ppHsType t = ppHsBType t - -ppHsForAllSeparator :: ForallVisFlag -> Doc -ppHsForAllSeparator ForallVis = text "->" -ppHsForAllSeparator ForallInvis = text "." - -ppHsBType (HsTyApp (HsTyCon (Qual (Module "Prelude") (HsTyClsName (HsSpecial "[]")))) b ) - = brackets $ ppHsType b -ppHsBType (HsTyApp a b) = fsep [ppHsBType a, ppHsAType b] -ppHsBType t = ppHsAType t - -ppHsAType :: HsType -> Doc -ppHsAType (HsTyTuple True l) = parenList . map ppHsType $ l -ppHsAType (HsTyTuple False l) = ubxParenList . map ppHsType $ l --- special case -ppHsAType (HsTyApp (HsTyCon (Qual (Module "Prelude") (HsTyClsName (HsSpecial "[]")))) b ) - = brackets $ ppHsType b -ppHsAType (HsTyVar name) = ppHsName name -ppHsAType (HsTyCon name) = ppHsQName name -ppHsAType t = parens $ ppHsType t - -ppHsQName :: HsQName -> Doc -ppHsQName (UnQual str) = ppHsName str -ppHsQName n@(Qual (Module mod) str) - | n == unit_con_name = ppHsName str - | isSpecial str = ppHsName str - | otherwise - = text "<link linkend=" <> ppLinkId mod str <> char '>' - <> ppHsName str - <> text "</link>" - -isSpecial (HsTyClsName id) | HsSpecial _ <- id = True -isSpecial (HsVarName id) | HsSpecial _ <- id = True -isSpecial _ = False - -ppHsName :: HsName -> Doc -ppHsName (HsTyClsName id) = ppHsIdentifier id -ppHsName (HsVarName id) = ppHsIdentifier id - -ppHsIdentifier :: HsIdentifier -> Doc -ppHsIdentifier (HsIdent str) = text str -ppHsIdentifier (HsSymbol str) = text str -ppHsIdentifier (HsSpecial str) = text str - -ppLinkId :: String -> HsName -> Doc -ppLinkId mod str - = hcat [char '\"', text mod, char '.', ppHsName str, char '\"'] - --- ----------------------------------------------------------------------------- --- * Misc - -parenList :: [Doc] -> Doc -parenList = parens . fsep . punctuate comma - -ubxParenList :: [Doc] -> Doc -ubxParenList = ubxparens . fsep . punctuate comma - -ubxparens p = text "(#" <> p <> text "#)" --} View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/68573aa57339eb6d1651a76016a7933… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/68573aa57339eb6d1651a76016a7933… You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][master] docs: drop obsolete warning about -fexternal-interpreter on windows
by Marge Bot (＠marge-bot) 15 Dec '25

15 Dec '25

Marge Bot pushed to branch master at Glasgow Haskell Compiler / GHC Commits: 2c2a3ef3 by Cheng Shao at 2025-12-15T11:51:53-05:00 docs: drop obsolete warning about -fexternal-interpreter on windows This patch drops an obsolete warning about -fexternal-interpreter not supported on windows; it is supported since a long time ago, including the profiled way. - - - - - 1 changed file: - docs/users_guide/ghci.rst Changes: ===================================== docs/users_guide/ghci.rst ===================================== @@ -1216,10 +1216,6 @@ Stack Traces in GHCi .. index:: simple: stack trace; in GHCi -[ This is an experimental feature enabled by the new -``-fexternal-interpreter`` flag that was introduced in GHC 8.0.1. It -is currently not supported on Windows.] - GHCi can use the profiling system to collect stack trace information when running interpreted code. To gain access to stack traces, start GHCi like this: View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/2c2a3ef30c644352f9f9d260cd84631… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/2c2a3ef30c644352f9f9d260cd84631… You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][wip/spj-try-opt-coercion] Wibble
by Simon Peyton Jones (＠simonpj) 15 Dec '25

15 Dec '25

Simon Peyton Jones pushed to branch wip/spj-try-opt-coercion at Glasgow Haskell Compiler / GHC Commits: 52dbcf4b by Simon Peyton Jones at 2025-12-15T15:44:33+00:00 Wibble - - - - - 1 changed file: - compiler/GHC/Core/Coercion/Opt.hs Changes: ===================================== compiler/GHC/Core/Coercion/Opt.hs ===================================== @@ -174,8 +174,9 @@ optCoercion :: OptCoercionOpts -> Subst -> Coercion -> NormalCo -- *and* optimises it to reduce its size optCoercion opts env co -- Experiment with no optCoercion at all - | False -- optCoercionEnabled opts - = optCoercion' env co + | optCoercionEnabled opts + = if False then optCoercion' env co + else substCo env co {- = pprTrace "optCoercion {" (text "Co:" <> ppr co) $ View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/52dbcf4b15f9dddd06931bae45ee5c5… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/52dbcf4b15f9dddd06931bae45ee5c5… You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc] Pushed new branch wip/fix-emit-barf
by Cheng Shao (＠TerrorJack) 15 Dec '25

15 Dec '25

Cheng Shao pushed new branch wip/fix-emit-barf at Glasgow Haskell Compiler / GHC -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/tree/wip/fix-emit-barf You're receiving this email because of your account on gitlab.haskell.org.

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[Git][ghc/ghc][wip/andreask/hls_fix] 13 commits: hadrian: add support for building with UndefinedBehaviorSanitizer
by Andreas Klebinger (＠AndreasK) 15 Dec '25

15 Dec '25

Andreas Klebinger pushed to branch wip/andreask/hls_fix at Glasgow Haskell Compiler / GHC Commits: 96fce8d0 by Cheng Shao at 2025-12-12T01:17:51+01:00 hadrian: add support for building with UndefinedBehaviorSanitizer This patch adds a +ubsan flavour transformer to hadrian to build all stage1+ C/C++ code with UndefinedBehaviorSanitizer. This is particularly useful to catch potential undefined behavior in the RTS codebase. - - - - - f7a06d8c by Cheng Shao at 2025-12-12T01:17:51+01:00 ci: update alpine/fedora & add ubsan job This patch updates alpine image to 3.23, fedora image to 43, and adds a `x86_64-linux-fedora43-validate+debug_info+ubsan` job that's run in validate/nightly pipelines to catch undefined behavior in the RTS codebase. - - - - - 2ccd11ca by Cheng Shao at 2025-12-12T01:17:51+01:00 rts: fix zero-length VLA undefined behavior in interpretBCO This commit fixes a zero-length VLA undefined behavior in interpretBCO, caught by UBSan: ``` +rts/Interpreter.c:3133:19: runtime variable length array bound evaluates to non-positive value 0 ``` - - - - - 4156ed19 by Cheng Shao at 2025-12-12T01:17:51+01:00 rts: fix unaligned ReadSpB in interpretBCO This commit fixes unaligned ReadSpB in interpretBCO, caught by UBSan: ``` +rts/Interpreter.c:2174:64: runtime load of misaligned address 0x004202059dd1 for type 'StgWord', which requires 8 byte alignment ``` To perform proper unaligned read, we define StgUnalignedWord as a type alias of StgWord with aligned(1) attribute, and load StgUnalignedWord instead of StgWord in ReadSpB, so the C compiler is aware that we're not loading with natural alignment. - - - - - fef89fb9 by Cheng Shao at 2025-12-12T01:17:51+01:00 rts: fix signed integer overflow in subword arithmetic in interpretBCO This commit fixes signed integer overflow in subword arithmetic in interpretBCO, see added note for detailed explanation. - - - - - 3c001377 by Cheng Shao at 2025-12-13T05:03:15-05:00 ci: use treeless fetch for perf notes This patch improves the ci logic for fetching perf notes by using treeless fetch (https://github.blog/open-source/git/get-up-to-speed-with-partial-clone-and-…) to avoid downloading all blobs of the perf notes repo at once, and only fetch the actually required blobs on-demand when needed. This makes the initial `test-metrics.sh pull` operation much faster, and also more robust, since we are seeing an increasing rate of 504 errors in CI when fetching all perf notes at once, which is a major source of CI flakiness at this point. Co-authored-by: Codex <codex(a)openai.com> - - - - - 123a8d77 by Peter Trommler at 2025-12-13T05:03:57-05:00 Cmm: remove restriction in MachOp folding - - - - - 0b54b5fd by Andreas Klebinger at 2025-12-13T05:04:38-05:00 Remove explicit Typeable deriviations. - - - - - 08b13f7b by Cheng Shao at 2025-12-13T05:05:18-05:00 ci: set gc.auto=0 during setup stage This patch sets `gc.auto=0` during `setup` stage of CI, see added comment for detailed explanation. - - - - - 3b5aecb5 by Ben Gamari at 2025-12-13T23:43:10+01:00 Bump exceptions submodule to 0.10.11 - - - - - c32de3b0 by Johan Förberg at 2025-12-15T02:36:03-05:00 base: Define Semigroup and Monoid instances for lazy ST CLC proposal: https://github.com/haskell/core-libraries-committee/issues/374 Fixes #26581 - - - - - 4f8b660c by mangoiv at 2025-12-15T02:37:05-05:00 ci: do not require nightly cabal-reinstall job to succeed - - - - - 31e648ba by Andreas Klebinger at 2025-12-15T15:05:53+01:00 Hadrian: When executing the cygpath executable include .exe ending for executable path - - - - - 33 changed files: - .gitlab-ci.yml - .gitlab/ci.sh - .gitlab/generate-ci/gen_ci.hs - .gitlab/jobs.yaml - .gitlab/rel_eng/fetch-gitlab-artifacts/fetch_gitlab.py - .gitlab/rel_eng/mk-ghcup-metadata/mk_ghcup_metadata.py - .gitlab/test-metrics.sh - compiler/GHC/Cmm/Opt.hs - hadrian/doc/flavours.md - hadrian/src/Flavour.hs - hadrian/src/Hadrian/Haskell/Cabal/Type.hs - hadrian/src/Hadrian/Haskell/Hash.hs - hadrian/src/Hadrian/Oracles/ArgsHash.hs - hadrian/src/Hadrian/Oracles/Cabal/Type.hs - hadrian/src/Hadrian/Oracles/DirectoryContents.hs - hadrian/src/Hadrian/Oracles/Path.hs - hadrian/src/Hadrian/Oracles/TextFile.hs - hadrian/src/Hadrian/Utilities.hs - hadrian/src/Oracles/Flavour.hs - hadrian/src/Oracles/ModuleFiles.hs - libraries/base/changelog.md - libraries/exceptions - libraries/ghc-internal/src/GHC/Internal/Control/Monad/ST/Lazy/Imp.hs - + rts/.ubsan-suppressions - rts/Interpreter.c - rts/include/stg/Types.h - rts/rts.cabal - testsuite/driver/testglobals.py - testsuite/driver/testlib.py - 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/interface-stability/base-exports.stdout-ws-32 The diff was not included because it is too large. View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/4c5ccef4c0061f392803e70bdfca77… -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/compare/4c5ccef4c0061f392803e70bdfca77… You're receiving this email because of your account on gitlab.haskell.org.

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