Marge Bot pushed to branch wip/marge_bot_batch_merge_job at Glasgow Haskell Compiler / GHC Commits: f108a972 by Arnaud Spiwack at 2026-02-27T12:53:01-05:00 Make list comprehension completely non-linear Fixes #25081 From the note: The usefulness of list comprehension in conjunction with linear types is dubious. After all, statements are made to be run many times, for instance in ```haskell [u | y <- [0,1], stmts] ``` both `u` and `stmts` are going to be run several times. In principle, though, there are some position in a monad comprehension expression which could be considered linear. We could try and make it so that these positions are considered linear by the typechecker, but in practice the desugarer doesn't take enough care to ensure that these are indeed desugared to linear sites. We tried in the past, and it turned out that we'd miss a desugaring corner case (#25772). Until there's a demand for this very specific improvement, let's instead be conservative, and consider list comprehension to be completely non-linear. - - - - - ae799cab by Simon Jakobi at 2026-02-27T12:53:54-05:00 PmAltConSet: Use Data.Set instead of Data.Map ...to store `PmLit`s. The Map was only used to map keys to themselves. Changing the Map to a Set saves a Word of memory per entry. Resolves #26756. - - - - - 18b64c1e by Vladislav Zavialov at 2026-02-27T13:25:34-05:00 Drop HsTyLit in favor of HsLit (#26862, #25121) This patch is a small step towards unification of HsExpr and HsType, taking care of literals (HsLit) and type literals (HsTyLit). Additionally, it improves error messages for unsupported type literals, such as unboxed or fractional literals (test cases: T26862, T26862_th). Changes to the AST: * Use HsLit where HsTyLit was previously used * Use HsChar where HsCharTy was previously used * Use HsString where HsStrTy was previously used * Use HsNatural (NEW) where HsNumTy was previously used * Use HsDouble (NEW) to represent unsupported fractional type literals Changes to logic: * Parse unboxed and fractional type literals (to be rejected later) * Drop the check for negative literals in the renamer (rnHsTyLit) in favor of checking in the type checker (tc_hs_lit_ty) * Check for invalid type literals in TH (repTyLit) and report unrepresentable literals with ThUnsupportedTyLit * Allow negative type literals in TH (numTyLit). This is fine as these will be taken care of at splice time (test case: T8306_th) - - - - - e24239a1 by Vladislav Zavialov at 2026-02-27T13:25:35-05:00 Increase test coverage of diagnostics Add test cases for the previously untested diagnostics: [GHC-01239] PsErrIfInFunAppExpr [GHC-04807] PsErrProcInFunAppExpr [GHC-08195] PsErrInvalidRecordCon [GHC-16863] PsErrUnsupportedBoxedSumPat [GHC-18910] PsErrSemiColonsInCondCmd [GHC-24737] PsErrInvalidWhereBindInPatSynDecl [GHC-25037] PsErrCaseInFunAppExpr [GHC-25078] PsErrPrecedenceOutOfRange [GHC-28021] PsErrRecordSyntaxInPatSynDecl [GHC-35827] TcRnNonOverloadedSpecialisePragma [GHC-40845] PsErrUnpackDataCon [GHC-45106] PsErrInvalidInfixHole [GHC-50396] PsErrInvalidRuleActivationMarker [GHC-63930] MultiWayIfWithoutAlts [GHC-65536] PsErrNoSingleWhereBindInPatSynDecl [GHC-67630] PsErrMDoInFunAppExpr [GHC-70526] PsErrLetCmdInFunAppCmd [GHC-77808] PsErrDoCmdInFunAppCmd [GHC-86934] ClassPE [GHC-90355] PsErrLetInFunAppExpr [GHC-91745] CasesExprWithoutAlts [GHC-92971] PsErrCaseCmdInFunAppCmd [GHC-95644] PsErrBangPatWithoutSpace [GHC-97005] PsErrIfCmdInFunAppCmd Remove unused error constructors: [GHC-44524] PsErrExpectedHyphen [GHC-91382] TcRnIllegalKindSignature - - - - - c7f6b7d3 by Torsten Schmits at 2026-02-27T13:25:36-05:00 Avoid expensive computation for debug logging in `mergeDatabases` when log level is low This computed and traversed a set intersection for every single dependency unconditionally. - - - - - 98 changed files: - compiler/GHC/Hs/Instances.hs - compiler/GHC/Hs/Lit.hs - compiler/GHC/Hs/Syn/Type.hs - compiler/GHC/Hs/Type.hs - compiler/GHC/HsToCore/Errors/Ppr.hs - compiler/GHC/HsToCore/Errors/Types.hs - compiler/GHC/HsToCore/Match/Literal.hs - compiler/GHC/HsToCore/Pmc/Solver/Types.hs - compiler/GHC/HsToCore/Quote.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/Expr.hs - compiler/GHC/Rename/HsType.hs - compiler/GHC/Rename/Pat.hs - compiler/GHC/Rename/Utils.hs - compiler/GHC/Tc/Errors/Ppr.hs - compiler/GHC/Tc/Errors/Types.hs - compiler/GHC/Tc/Gen/App.hs - compiler/GHC/Tc/Gen/HsType.hs - compiler/GHC/Tc/Gen/Match.hs - compiler/GHC/Tc/Gen/Pat.hs - compiler/GHC/ThToHs.hs - compiler/GHC/Types/Error/Codes.hs - compiler/GHC/Types/SourceText.hs - compiler/GHC/Unit/State.hs - compiler/Language/Haskell/Syntax/Expr.hs - compiler/Language/Haskell/Syntax/Extension.hs - compiler/Language/Haskell/Syntax/Lit.hs - compiler/Language/Haskell/Syntax/Type.hs - libraries/ghc-internal/src/GHC/Internal/TH/Lib.hs - + testsuite/tests/dependent/should_fail/SelfDepCls.hs - + testsuite/tests/dependent/should_fail/SelfDepCls.stderr - testsuite/tests/dependent/should_fail/all.T - testsuite/tests/diagnostic-codes/codes.stdout - testsuite/tests/ghc-api/annotations-literals/parsed.hs - − testsuite/tests/linear/should_compile/LinearListComprehension.hs - testsuite/tests/linear/should_compile/all.T - testsuite/tests/linear/should_fail/T25081.hs - testsuite/tests/linear/should_fail/T25081.stderr - testsuite/tests/module/all.T - + testsuite/tests/module/mod70b.hs - + testsuite/tests/module/mod70b.stderr - + testsuite/tests/parser/should_fail/NoBlockArgumentsFail4.hs - + testsuite/tests/parser/should_fail/NoBlockArgumentsFail4.stderr - testsuite/tests/parser/should_fail/NoBlockArgumentsFailArrowCmds.hs - testsuite/tests/parser/should_fail/NoBlockArgumentsFailArrowCmds.stderr - + testsuite/tests/parser/should_fail/NoDoAndIfThenElseArrowCmds.hs - + testsuite/tests/parser/should_fail/NoDoAndIfThenElseArrowCmds.stderr - testsuite/tests/parser/should_fail/all.T - + testsuite/tests/parser/should_fail/badRuleMarker.hs - + testsuite/tests/parser/should_fail/badRuleMarker.stderr - + testsuite/tests/parser/should_fail/patFail010.hs - + testsuite/tests/parser/should_fail/patFail010.stderr - + testsuite/tests/parser/should_fail/patFail011.hs - + testsuite/tests/parser/should_fail/patFail011.stderr - + testsuite/tests/parser/should_fail/precOutOfRange.hs - + testsuite/tests/parser/should_fail/precOutOfRange.stderr - + testsuite/tests/parser/should_fail/unpack_data_con.hs - + testsuite/tests/parser/should_fail/unpack_data_con.stderr - testsuite/tests/patsyn/should_fail/T10426.stderr - testsuite/tests/patsyn/should_fail/all.T - + testsuite/tests/patsyn/should_fail/patsyn_where_fail1.hs - + testsuite/tests/patsyn/should_fail/patsyn_where_fail1.stderr - + testsuite/tests/patsyn/should_fail/patsyn_where_fail2.hs - + testsuite/tests/patsyn/should_fail/patsyn_where_fail2.stderr - + testsuite/tests/patsyn/should_fail/patsyn_where_fail3.hs - + testsuite/tests/patsyn/should_fail/patsyn_where_fail3.stderr - + testsuite/tests/patsyn/should_fail/patsyn_where_fail4.hs - + testsuite/tests/patsyn/should_fail/patsyn_where_fail4.stderr - + testsuite/tests/th/T26862_th.script - + testsuite/tests/th/T26862_th.stderr - + testsuite/tests/th/T8306_th.script - + testsuite/tests/th/T8306_th.stderr - + testsuite/tests/th/T8306_th.stdout - testsuite/tests/th/T8412.stderr - + testsuite/tests/th/TH_EmptyLamCases.hs - + testsuite/tests/th/TH_EmptyLamCases.stderr - + testsuite/tests/th/TH_EmptyMultiIf.hs - + testsuite/tests/th/TH_EmptyMultiIf.stderr - testsuite/tests/th/all.T - + testsuite/tests/typecheck/should_fail/T26862.hs - + testsuite/tests/typecheck/should_fail/T26862.stderr - testsuite/tests/typecheck/should_fail/T8306.stderr - testsuite/tests/typecheck/should_fail/all.T - testsuite/tests/unboxedsums/all.T - + testsuite/tests/unboxedsums/unboxedsums4p.hs - + testsuite/tests/unboxedsums/unboxedsums4p.stderr - + testsuite/tests/warnings/should_compile/SpecMultipleTysMono.hs - + testsuite/tests/warnings/should_compile/SpecMultipleTysMono.stderr - testsuite/tests/warnings/should_compile/all.T - utils/check-exact/ExactPrint.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/Interface/Rename.hs - utils/haddock/haddock-api/src/Haddock/Types.hs The diff was not included because it is too large. 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