Simon Peyton Jones pushed to branch wip/T26868 at Glasgow Haskell Compiler / GHC Commits: 58009c14 by Apoorv Ingle at 2026-04-02T09:51:24+01:00 Streamline expansions using HsExpansion (#25001) Notes added [Error Context Stack] [Typechecking by expansion: overview] Notes updated Note [Expanding HsDo with XXExprGhcRn] [tcApp: typechecking applications] ------------------------- Metric Decrease: T9020 ------------------------- There are 2 key changes: 1. `HsExpand` datatype mediates between expansions 2. Replace `ErrCtxtM` to a simpler `HsCtxt` that does not depend on a `TidyEnv` This has some consequences detailed below: 1. `HsExpand` datatype mediates between expansions * Simplifies the implementations of `tcExpr` to work on `XExpr` * Removes `VACtxt` (and its associated `VAExpansion` and `VACall`) datatype, it is subsumed by simply a `SrcSpan`. * Removes the function `addHeadCtxt` as it is now mearly setting a location * The function `tcValArgs` does its own argument number management * move `splitHsTypes` out of `tcApp` * Removes special case of tcBody from `tcLambdaMatches` * Removes special case of `dsExpr` for `ExpandedThingTc` * Renames `tcMonoExpr` -> `tcMonoLExpr`, `tcMonoExprNC` -> `tcMonoLExpr` * Renames `EValArg`, `EValArgQL` fields: `ea_ctxt` -> `ea_loc_span` and `eaql_ctx` -> `eaql_loc_span` * Remove `PopErrCtxt` from `XXExprGhcRn` * `fun_orig` in tcInstFun depends on the SrcSpan of the head of the application chain (similar to addArgCtxt) - it references the application chain head if it is user located, or uses the error context stack as a fallback if it's a generated location * Make a new variant `GeneratedSrcSpan` in `SrcSpan` for HIEAst Nodes - Expressions wrapped around `GeneratedSrcSpan` are ignored and never added to the error context stack - In Explicit list expansion `fromListN` is wrapped with a `GeneratedSrcSpan` with `GeneratedSrcSpanDetails` field to store the original srcspan 2. Replace `ErrCtxtM` to a simpler `HsCtxt` that does not depend on a `TidyEnv` * Merge `HsThingRn` to `HsCtxt` * Landmark Error messages are now just computed on the fly * Make HsExpandedRn and HsExpandedTc payload a located HsExpr GhcRn * `HsCtxt` are tidied and zonked at the end right before printing Co-authored-by: simonpj <simon.peytonjones@gmail.com> - - - - - bc4b4487 by Zubin Duggal at 2026-04-03T14:22:27-04:00 driver: recognise .dyn_o as a valid object file to link if passed on the command line. This allows plugins compiled with this suffix to run. Fixes #24486 - - - - - 5ebb9121 by Simon Jakobi at 2026-04-03T14:23:11-04:00 Add regression test for #16145 Closes #16145. - - - - - 3ec86aeb by Simon Peyton Jones at 2026-04-03T19:43:08+01:00 Add Invariant (NoTypeShadowing) to Core This commit addresses #26868, by adding a new invariant (NoTypeShadowing) to Core. See Note [No type-shadowing in Core] in GHC.Core - - - - - 33ecfbb5 by Simon Peyton Jones at 2026-04-03T20:56:12+01:00 Major refactor of free-variable functions For some time we have had two free-variable mechanims for types: * The "FV" mechanism, embodied in GHC.Utils.FV, which worked OK, but was fragile where eta-expansion was concerned. * The TyCoFolder mechanism, using a one-shot EndoOS accumulator I finally got tired of this and refactored the whole thing, thereby addressing #27080. Now we have * `GHC.Types.Var.FV`, which has a composable free-variable result type, very much in the spirit of the old `FV`, but much more robust. (It uses the "one shot trick".) * GHC.Core.TyCo.FVs now has just one technology for free variables. All this led to a lot of renaming. There are couple of error-message changes. The change in T18451 makes an already-poor error message even more mysterious. But it really needs a separate look. We also now traverse the AST in a different order leading to a different but still deterministic order for FVs and test output has been adjusted accordingly. - - - - - 196 changed files: - compiler/GHC.hs - compiler/GHC/Core.hs - compiler/GHC/Core/Coercion.hs - compiler/GHC/Core/FVs.hs - compiler/GHC/Core/Lint.hs - compiler/GHC/Core/Opt/DmdAnal.hs - compiler/GHC/Core/Opt/SetLevels.hs - compiler/GHC/Core/Opt/Specialise.hs - compiler/GHC/Core/Rules.hs - compiler/GHC/Core/Subst.hs - compiler/GHC/Core/TyCo/FVs.hs - compiler/GHC/Core/TyCo/Rep.hs - compiler/GHC/Core/TyCo/Subst.hs - compiler/GHC/Core/Type.hs - compiler/GHC/Core/Unify.hs - compiler/GHC/Driver/Phases.hs - compiler/GHC/Hs/DocString.hs - compiler/GHC/Hs/Expr.hs - compiler/GHC/Hs/Expr.hs-boot - compiler/GHC/Hs/Instances.hs - compiler/GHC/Hs/Syn/Type.hs - compiler/GHC/Hs/Utils.hs - compiler/GHC/HsToCore/Binds.hs - compiler/GHC/HsToCore/Expr.hs - compiler/GHC/HsToCore/Match.hs - compiler/GHC/HsToCore/Monad.hs - compiler/GHC/HsToCore/Pmc.hs - compiler/GHC/HsToCore/Quote.hs - compiler/GHC/HsToCore/Ticks.hs - compiler/GHC/Iface/Ext/Ast.hs - compiler/GHC/Iface/Ext/Utils.hs - compiler/GHC/Iface/Syntax.hs - compiler/GHC/Parser/HaddockLex.x - compiler/GHC/Rename/Bind.hs - compiler/GHC/Rename/Env.hs - compiler/GHC/Rename/Expr.hs - compiler/GHC/Rename/Expr.hs-boot - compiler/GHC/Rename/HsType.hs - compiler/GHC/Rename/Lit.hs - compiler/GHC/Rename/Module.hs - compiler/GHC/Rename/Names.hs - compiler/GHC/Rename/Pat.hs - compiler/GHC/Rename/Splice.hs - compiler/GHC/Rename/Splice.hs-boot - compiler/GHC/Rename/Utils.hs - compiler/GHC/Runtime/Debugger/Breakpoints.hs - compiler/GHC/Tc/Deriv.hs - compiler/GHC/Tc/Deriv/Infer.hs - compiler/GHC/Tc/Deriv/Utils.hs - compiler/GHC/Tc/Errors.hs - compiler/GHC/Tc/Errors/Hole.hs - compiler/GHC/Tc/Errors/Ppr.hs - compiler/GHC/Tc/Errors/Types.hs - compiler/GHC/Tc/Gen/App.hs - compiler/GHC/Tc/Gen/Bind.hs - compiler/GHC/Tc/Gen/Do.hs - + compiler/GHC/Tc/Gen/Expand.hs - compiler/GHC/Tc/Gen/Export.hs - compiler/GHC/Tc/Gen/Expr.hs - compiler/GHC/Tc/Gen/Expr.hs-boot - compiler/GHC/Tc/Gen/Head.hs - compiler/GHC/Tc/Gen/HsType.hs - compiler/GHC/Tc/Gen/Match.hs - compiler/GHC/Tc/Gen/Match.hs-boot - compiler/GHC/Tc/Gen/Pat.hs - compiler/GHC/Tc/Gen/Sig.hs - compiler/GHC/Tc/Gen/Splice.hs - compiler/GHC/Tc/Instance/Class.hs - compiler/GHC/Tc/Instance/Family.hs - compiler/GHC/Tc/Instance/FunDeps.hs - compiler/GHC/Tc/Module.hs - compiler/GHC/Tc/Solver/Solve.hs - compiler/GHC/Tc/TyCl.hs - compiler/GHC/Tc/TyCl/Class.hs - compiler/GHC/Tc/TyCl/Instance.hs - compiler/GHC/Tc/TyCl/PatSyn.hs - compiler/GHC/Tc/TyCl/Utils.hs - compiler/GHC/Tc/Types.hs - compiler/GHC/Tc/Types/BasicTypes.hs - compiler/GHC/Tc/Types/Constraint.hs - compiler/GHC/Tc/Types/CtLoc.hs - compiler/GHC/Tc/Types/ErrCtxt.hs - compiler/GHC/Tc/Types/Evidence.hs - compiler/GHC/Tc/Types/LclEnv.hs - compiler/GHC/Tc/Types/Origin.hs - compiler/GHC/Tc/Types/Origin.hs-boot - compiler/GHC/Tc/Utils/Instantiate.hs - compiler/GHC/Tc/Utils/Monad.hs - compiler/GHC/Tc/Utils/TcMType.hs - compiler/GHC/Tc/Utils/TcType.hs - compiler/GHC/Tc/Utils/TcType.hs-boot - compiler/GHC/Tc/Utils/Unify.hs - compiler/GHC/Tc/Validity.hs - compiler/GHC/Tc/Zonk/TcType.hs - compiler/GHC/Tc/Zonk/Type.hs - compiler/GHC/Types/Error.hs - + compiler/GHC/Types/Error.hs-boot - compiler/GHC/Types/Hint/Ppr.hs - compiler/GHC/Types/Name/Reader.hs - compiler/GHC/Types/Name/Set.hs - compiler/GHC/Types/SrcLoc.hs - + compiler/GHC/Types/Var/FV.hs - compiler/GHC/Types/Var/Set.hs - + compiler/GHC/Unit/State.hs-boot - compiler/GHC/Utils/Binary.hs - compiler/GHC/Utils/EndoOS.hs - − compiler/GHC/Utils/FV.hs - compiler/GHC/Utils/Logger.hs - compiler/ghc.cabal.in - ghc/GHCi/UI.hs - ghc/GHCi/UI/Info.hs - testsuite/tests/count-deps/CountDepsAst.stdout - testsuite/tests/count-deps/CountDepsParser.stdout - testsuite/tests/cpranal/should_compile/T18401.stderr - testsuite/tests/deriving/should_fail/deriving-via-fail4.stderr - testsuite/tests/ghci/prog-mhu001/prog-mhu001c.stdout - testsuite/tests/indexed-types/should_fail/T2693.stderr - testsuite/tests/indexed-types/should_fail/T5439.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/monadfail/MonadFailErrors.stderr - testsuite/tests/overloadedrecflds/should_fail/T26480b.stderr - testsuite/tests/parser/should_fail/RecordDotSyntaxFail10.stderr - testsuite/tests/parser/should_fail/RecordDotSyntaxFail11.stderr - testsuite/tests/parser/should_fail/RecordDotSyntaxFail9.stderr - testsuite/tests/partial-sigs/should_compile/SplicesUsed.stderr - testsuite/tests/partial-sigs/should_compile/T10403.stderr - testsuite/tests/partial-sigs/should_compile/T12844.stderr - testsuite/tests/partial-sigs/should_compile/T15039a.stderr - testsuite/tests/partial-sigs/should_compile/T15039b.stderr - testsuite/tests/partial-sigs/should_compile/T15039c.stderr - testsuite/tests/partial-sigs/should_compile/T15039d.stderr - testsuite/tests/partial-sigs/should_fail/T10999.stderr - testsuite/tests/partial-sigs/should_fail/T12634.stderr - testsuite/tests/plugins/Makefile - + testsuite/tests/plugins/T24486-plugin/Makefile - + testsuite/tests/plugins/T24486-plugin/Setup.hs - + testsuite/tests/plugins/T24486-plugin/T24486-plugin.cabal - + testsuite/tests/plugins/T24486-plugin/T24486_Plugin.hs - + testsuite/tests/plugins/T24486.hs - + testsuite/tests/plugins/T24486_Helper.hs - testsuite/tests/plugins/all.T - testsuite/tests/plugins/test-defaulting-plugin.stderr - testsuite/tests/polykinds/T15789.stderr - testsuite/tests/polykinds/T18451.stderr - testsuite/tests/polykinds/T7328.stderr - testsuite/tests/printer/T17697.stderr - testsuite/tests/profiling/should_run/callstack001.stdout - testsuite/tests/rebindable/rebindable6.stderr - testsuite/tests/rep-poly/RepPolyRecordUpdate.stderr - testsuite/tests/runghc/Makefile - + testsuite/tests/runghc/T16145.hs - + testsuite/tests/runghc/T16145.stdout - + testsuite/tests/runghc/T16145_aux.hs - testsuite/tests/runghc/all.T - testsuite/tests/simplCore/should_compile/DsSpecPragmas.stderr - testsuite/tests/simplCore/should_compile/T24229a.stderr - testsuite/tests/simplCore/should_compile/T24229b.stderr - testsuite/tests/simplCore/should_compile/T24359a.stderr - testsuite/tests/simplCore/should_compile/T26116.stderr - testsuite/tests/simplCore/should_compile/T4908.stderr - testsuite/tests/simplCore/should_compile/spec-inline.stderr - testsuite/tests/typecheck/no_skolem_info/T20063.stderr - + testsuite/tests/typecheck/should_compile/ExpansionQLIm.hs - testsuite/tests/typecheck/should_compile/T14590.stderr - testsuite/tests/typecheck/should_compile/T25180.stderr - testsuite/tests/typecheck/should_compile/all.T - testsuite/tests/typecheck/should_compile/free_monad_hole_fits.stderr - testsuite/tests/typecheck/should_compile/valid_hole_fits.stderr - testsuite/tests/typecheck/should_fail/DoExpansion1.stderr - testsuite/tests/typecheck/should_fail/DoExpansion2.stderr - testsuite/tests/typecheck/should_fail/T10971d.stderr - testsuite/tests/typecheck/should_fail/T12589.stderr - testsuite/tests/typecheck/should_fail/T13311.stderr - testsuite/tests/typecheck/should_fail/T17773.stderr - testsuite/tests/typecheck/should_fail/T2846b.stderr - testsuite/tests/typecheck/should_fail/T3323.stderr - testsuite/tests/typecheck/should_fail/T3613.stderr - testsuite/tests/typecheck/should_fail/T6069.stderr - testsuite/tests/typecheck/should_fail/T7851.stderr - testsuite/tests/typecheck/should_fail/T7857.stderr - testsuite/tests/typecheck/should_fail/T8603.stderr - testsuite/tests/typecheck/should_fail/T9612.stderr - testsuite/tests/typecheck/should_fail/tcfail102.stderr - testsuite/tests/typecheck/should_fail/tcfail128.stderr - testsuite/tests/typecheck/should_fail/tcfail140.stderr - testsuite/tests/typecheck/should_fail/tcfail181.stderr - utils/check-exact/ExactPrint.hs - utils/check-exact/Parsers.hs - utils/check-exact/Transform.hs - utils/check-exact/Utils.hs - utils/haddock/haddock-api/src/Haddock/Backends/Hyperlinker/Parser.hs - utils/haddock/haddock-api/src/Haddock/Backends/Xhtml/Utils.hs - utils/haddock/haddock-api/src/Haddock/GhcUtils.hs The diff was not included because it is too large. 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