Marge Bot pushed to branch wip/marge_bot_batch_merge_job at Glasgow Haskell Compiler / GHC Commits: 427fbe14 by Adam Gundry at 2026-03-18T12:26:54-04:00 ghci: Mention active language edition in startup banner Per GHC proposal 632, this makes the GHCi startup banner include the active language edition, plus an indication of whether this was the default (as opposed to being explicitly selected via an option such as `-XGHC2024`). For example: ``` $ ghci GHCi, version 9.14.1: https://www.haskell.org/ghc/ :? for help Using default language edition: GHC2024 ghci> ``` Fixes #26037. - - - - - a0f0904f by sheaf at 2026-03-18T12:27:02-04:00 Improve incomplete record selector warnings This commit stops GHC from emitting spurious incomplete record selector warnings for bare selectors/projections such as .fld There are two places we currently emit incomplete record selector warnings: 1. In the desugarer, when we see a record selector or an occurrence of 'getField'. Here, we can use pattern matching information to ensure we don't give false positives. 2. In the typechecker, which might sometimes give false positives but can emit warnings in cases that the pattern match checker would otherwise miss. This is explained in Note [Detecting incomplete record selectors] in GHC.HsToCore.Pmc. Now, we obviously don't want to emit the same error twice, and generally we prefer (1), as those messages contain fewer false positives. So we suppress (2) when we are sure we are going to emit (1); the logic for doing so is in GHC.Tc.Instance.Class.warnIncompleteRecSel, and works by looking at the CtOrigin. Now, the issue was that this logic handled explicit record selectors as well as overloaded record field selectors such as "x.r" (which turns into a simple GetFieldOrigin CtOrigin), but it didn't properly handle record projectors like ".fld" or ".fld1.fld2" (which result in other CtOrigins such as 'RecordFieldProjectionOrigin'). To solve this problem, we re-use the 'isHasFieldOrigin' introduced in fbdc623a (slightly adjusted). On the way, we also had to update the desugarer with special handling for the 'ExpandedThingTc' case in 'ds_app', to make sure that 'ds_app_var' sees all the type arguments to 'getField' in order for it to indeed emit warnings like in (1). Fixes #26686 - - - - - 35093c67 by Cheng Shao at 2026-03-18T12:27:04-04:00 rts: opportunistically grow the MutableByteArray# in-place in resizeMutableByteArray# Following !15234, this patch improves `resizeMutableByteArray#` memory efficiency by growing the `MutableByteArray#` in-place if possible, addressing an old todo comment here. Also adds a new test case `resizeMutableByteArrayInPlace` that stresses this behavior. - - - - - c93b0ca5 by Matthew Craven at 2026-03-18T12:27:10-04:00 Change representation of floating point literals This commit changes the representation of floating point literals throughough the compiler, in particular in Core and Cmm. The Rational type is deficient for this purpose, dealing poorly with NaN, +/-Infinity, and negative zero. Instead, the new module GHC.Types.Literal.Floating uses the host Float/Double type to represent NaNs, infinities and negative zero. It also contains a Rational constructor, for the benefit of -fexcess-precision. Other changes: - Remove Note [negative zero] and related code This also removes the restrictions on constant-folding of division by zero, and should make any problems with NaN/Infinity more obvious. - Use -0.0 as the additive identity for Core constant folding rules for floating-point addition, fixing #21227. - Manual worker-wrapper for GHC.Float.rationalToDouble. This is intended to prevent the compiler's WW on this function from interfering with constant-folding. This change means that we now avoid allocating a box for the result of a 'realToFrac' call in T10359. - Combine floatDecodeOp and doubleDecodeOp. This change also fixes a bug in doubleDecodeOp wherein it would incorrectly produce an Int# instead of an Int64# literal for the mantissa component with 64-bit targets. - Use Float/Double for assembly immediates, and update the X86 and PowerPC backends to properly handle special values such as NaN and infinity. - Allow 'rational_to' to handle zero denominators, fixing a TODO in GHC.Core.Opt.ConstantFold. Fixes #8364 #9811 #18897 #21227 Progress towards #26919 Metric Decrease: T10359 Co-authored-by: sheaf <sam.derbyshire@gmail.com> - - - - - 68fa0636 by Sylvain Henry at 2026-03-18T12:27:41-04:00 Core: add constant-folding rules for Addr# eq/ne (#18032) - - - - - 1c90b9b1 by Matthew Pickering at 2026-03-18T12:27:43-04:00 Use OsPath rather than FilePath in Downsweep cache This gets us one step closure to uniformly using `OsPath` in the compiler. - - - - - f1caa8a2 by Cheng Shao at 2026-03-18T12:27:44-04:00 hadrian: fix ghc-in-ghci flavour stage0 shared libraries This patch fixes missing stage0 shared libraries in hadrian ghc-in-ghci flavour, which was accidentally dropped in 669d09f950a6e88b903d9fd8a7571531774d4d5d and resulted in a regression in HLS support on linux/macos. Fixes #27057. - - - - - 68 changed files: - compiler/GHC/Builtin/Names.hs - compiler/GHC/ByteCode/Asm.hs - compiler/GHC/Cmm/CommonBlockElim.hs - compiler/GHC/Cmm/Expr.hs - compiler/GHC/Cmm/Opt.hs - compiler/GHC/Cmm/Parser.y - compiler/GHC/Cmm/Type.hs - compiler/GHC/CmmToAsm/AArch64/CodeGen.hs - compiler/GHC/CmmToAsm/AArch64/Ppr.hs - compiler/GHC/CmmToAsm/AArch64/Regs.hs - compiler/GHC/CmmToAsm/LA64/CodeGen.hs - compiler/GHC/CmmToAsm/LA64/Ppr.hs - compiler/GHC/CmmToAsm/LA64/Regs.hs - compiler/GHC/CmmToAsm/PPC/CodeGen.hs - compiler/GHC/CmmToAsm/PPC/Ppr.hs - compiler/GHC/CmmToAsm/PPC/Regs.hs - compiler/GHC/CmmToAsm/RV64/CodeGen.hs - compiler/GHC/CmmToAsm/RV64/Ppr.hs - compiler/GHC/CmmToAsm/RV64/Regs.hs - compiler/GHC/CmmToAsm/Wasm/FromCmm.hs - compiler/GHC/CmmToAsm/X86/CodeGen.hs - compiler/GHC/CmmToAsm/X86/Ppr.hs - compiler/GHC/CmmToAsm/X86/Regs.hs - compiler/GHC/CmmToC.hs - compiler/GHC/CmmToLlvm/CodeGen.hs - compiler/GHC/CmmToLlvm/Data.hs - compiler/GHC/Core.hs - compiler/GHC/Core/Make.hs - compiler/GHC/Core/Opt/ConstantFold.hs - compiler/GHC/Driver/Downsweep.hs - compiler/GHC/HsToCore/Expr.hs - compiler/GHC/HsToCore/Match/Literal.hs - compiler/GHC/HsToCore/Pmc.hs - compiler/GHC/HsToCore/Pmc/Solver/Types.hs - compiler/GHC/Stg/Unarise.hs - compiler/GHC/StgToByteCode.hs - compiler/GHC/StgToCmm/Lit.hs - compiler/GHC/StgToCmm/Prim.hs - compiler/GHC/StgToJS/Literal.hs - compiler/GHC/Tc/Errors.hs - compiler/GHC/Tc/Instance/Class.hs - compiler/GHC/Tc/Types/Origin.hs - compiler/GHC/Types/Literal.hs - + compiler/GHC/Types/Literal/Floating.hs - compiler/GHC/Utils/Binary.hs - compiler/ghc.cabal.in - docs/users_guide/9.16.1-notes.rst - ghc/GHCi/UI.hs - ghc/Main.hs - hadrian/src/Settings/Flavours/GhcInGhci.hs - libraries/ghc-internal/src/GHC/Internal/Float.hs - rts/PrimOps.cmm - + testsuite/tests/codeGen/should_run/T21227.hs - + testsuite/tests/codeGen/should_run/T21227.stdout - + testsuite/tests/codeGen/should_run/T9811.hs - + testsuite/tests/codeGen/should_run/T9811.stdout - testsuite/tests/codeGen/should_run/all.T - testsuite/tests/count-deps/CountDepsAst.stdout - testsuite/tests/count-deps/CountDepsParser.stdout - testsuite/tests/numeric/should_run/T7014.hs - + testsuite/tests/overloadedrecflds/should_compile/T26686.hs - + testsuite/tests/overloadedrecflds/should_compile/T26686.stderr - testsuite/tests/overloadedrecflds/should_compile/all.T - testsuite/tests/rts/all.T - + testsuite/tests/rts/resizeMutableByteArrayInPlace.hs - + testsuite/tests/simplCore/should_compile/T18032.hs - + testsuite/tests/simplCore/should_compile/T18032.stderr - testsuite/tests/simplCore/should_compile/all.T The diff was not included because it is too large. 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