sheaf pushed to branch wip/spj-reinstallable-base2 at Glasgow Haskell Compiler / GHC

Commits:

• 18d740ac
  by sheaf at 2026-08-07T02:54:34+02:00

  Allow GHC.Essentials to be hidden
  
  This commit overhauls several aspects of the known entity handling,
  in order to allow GHC.Essentials to be hidden without a proliferation
  of special cases in the compiler.
  
  The main contribution is to introduce the 'UnresolvedImport' datatype
  which cleans up a lot of ad-hoc handling relating to 'ModSummary',
  fixing #27603. This allows us to reduce duplication, e.g. by having
  Backpack reuse 'mkUnresolvedImports' instead of replicating the
  "add implicit imports" logic. It also makes it easier to avoid
  undesirable edge cases (such as making sure that the Template Haskell
  'reifyModule' function does not leak the implicit GHC.Essentials import).
  In particular, the infamous 'findImportedModuleWithIsBoot' is now simply
  'resolveImport', taking a single 'UnresolvedImport' and resolving it
  to a 'FindResult' (usually a 'Module').
  
  Other changes:
  
    - Cache the result of looking up GHC.Essentials (in TcM and DsM
      environments) to avoid redundant work.
      This reduces allocations on LinkableUsage01 and hard_hole_fits.
    - Properly look up known entities for StaticPointers like we do for
      other known entities everywhere else. This allows e.g. modules in
      ghc-internal to use -XStaticPointers.
    - When using multiple home units, we are now careful to handle the
      situation in which we may have multiple GHC.Essentials modules
      around. See the new tests under 'driver/multipleHomeUnits'.
  

107 changed files:

• compiler/GHC.hs
• compiler/GHC/Builtin.hs
• compiler/GHC/Builtin/Modules.hs
• compiler/GHC/Driver/Backpack.hs
• compiler/GHC/Driver/Config/Tidy.hs
• compiler/GHC/Driver/Downsweep.hs
• compiler/GHC/Driver/Main/Passes.hs
• compiler/GHC/Driver/Make.hs
• compiler/GHC/Driver/MakeFile.hs
• compiler/GHC/Driver/Pipeline/Execute.hs
• compiler/GHC/Hs/ImpExp.hs
• compiler/GHC/HsToCore.hs
• compiler/GHC/HsToCore/Monad.hs
• compiler/GHC/HsToCore/Types.hs
• compiler/GHC/HsToCore/Usage.hs
• compiler/GHC/Iface/Errors/Ppr.hs
• compiler/GHC/Iface/Errors/Types.hs
• compiler/GHC/Iface/Ext/Ast.hs
• compiler/GHC/Iface/Load.hs
• compiler/GHC/Iface/Make.hs
• compiler/GHC/Iface/Recomp.hs
• compiler/GHC/Iface/Syntax.hs
• compiler/GHC/IfaceToCore.hs
• compiler/GHC/Parser.y
• compiler/GHC/Parser/Header.hs
• compiler/GHC/Rename/Env.hs
• compiler/GHC/Rename/Names.hs
• compiler/GHC/Runtime/Eval.hs
• compiler/GHC/Tc/Gen/Splice.hs
• compiler/GHC/Tc/Module.hs
• compiler/GHC/Tc/Plugin.hs
• compiler/GHC/Tc/Types.hs
• compiler/GHC/Tc/Utils/Backpack.hs
• compiler/GHC/Tc/Utils/Env.hs
• compiler/GHC/Tc/Utils/Monad.hs
• + compiler/GHC/Types/UnresolvedImport.hs
• compiler/GHC/Unit/External.hs
• compiler/GHC/Unit/External/ModuleOrigin.hs
• compiler/GHC/Unit/External/Providers.hs
• compiler/GHC/Unit/Finder.hs
• compiler/GHC/Unit/Finder/Types.hs
• compiler/GHC/Unit/Module/Deps.hs
• compiler/GHC/Unit/Module/ModSummary.hs
• compiler/GHC/Unit/State.hs
• compiler/GHC/Unit/Types.hs
• compiler/ghc.cabal.in
• ghc/GHCi/UI.hs
• ghc/Main.hs
• libraries/base/base.cabal.in
• linters/lint-codes/LintCodes/Static.hs
• testsuite/driver/testutil.py
• testsuite/tests/cabal/T12485/Makefile
• testsuite/tests/count-deps/CountDepsParser.stdout
• testsuite/tests/diagnostic-codes/codes.stdout
• testsuite/tests/driver/T27013e/T27013e.hs
• testsuite/tests/driver/T27013e/T27013e.stderr
• testsuite/tests/driver/T27013f/T27013f.hs
• testsuite/tests/driver/T27013f/T27013f.stderr
• + testsuite/tests/driver/T27013g/T27013g.hs
• + testsuite/tests/driver/T27013g/all.T
• + testsuite/tests/driver/T27013h/GHC/Essentials.hs
• + testsuite/tests/driver/T27013h/T27013h.stderr
• + testsuite/tests/driver/T27013h/all.T
• + testsuite/tests/driver/T27013h/unitT27013h
• + testsuite/tests/driver/T27013i/T27013i.hs
• + testsuite/tests/driver/T27013i/T27013i.stderr
• + testsuite/tests/driver/T27013i/all.T
• testsuite/tests/driver/multipleHomeUnits/Makefile
• testsuite/tests/driver/multipleHomeUnits/all.T
• + testsuite/tests/driver/multipleHomeUnits/essentials-home/GHC/Essentials.hs
• + testsuite/tests/driver/multipleHomeUnits/essentials-order-base/B.hs
• + testsuite/tests/driver/multipleHomeUnits/essentials-order-user/U.hs
• + testsuite/tests/driver/multipleHomeUnits/essentials-user/M.hs
• testsuite/tests/driver/multipleHomeUnits/multipleHomeUnitsModuleVisibility.stderr
• + testsuite/tests/driver/multipleHomeUnits/multipleHomeUnits_essentials.stdout
• + testsuite/tests/driver/multipleHomeUnits/multipleHomeUnits_essentials_order.stderr
• + testsuite/tests/driver/multipleHomeUnits/multipleHomeUnits_essentials_recomp.stdout
• + testsuite/tests/driver/multipleHomeUnits/unitEssentialsHome
• + testsuite/tests/driver/multipleHomeUnits/unitEssentialsHomeHidden
• + testsuite/tests/driver/multipleHomeUnits/unitEssentialsOrderBase
• + testsuite/tests/driver/multipleHomeUnits/unitEssentialsOrderUser
• + testsuite/tests/driver/multipleHomeUnits/unitEssentialsUser
• + testsuite/tests/driver/multipleHomeUnits/unitEssentialsUserHidden
• + testsuite/tests/ghc-api/EssentialsCoverage.hs
• testsuite/tests/ghc-api/all.T
• testsuite/tests/ghc-api/downsweep/PartialDownsweep.hs
• testsuite/tests/ghci/scripts/ListTuplePunsPpr.stdout
• testsuite/tests/ghci/scripts/T4175.stdout
• testsuite/tests/ghci/scripts/all.T
• testsuite/tests/ghci/scripts/ghci064.stdout
• 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/module/mod185.stderr
• testsuite/tests/parser/should_compile/DumpParsedAst.stderr
• testsuite/tests/parser/should_compile/DumpRenamedAst.stderr
• testsuite/tests/parser/should_compile/DumpSemis.stderr
• testsuite/tests/parser/should_compile/KindSigs.stderr
• testsuite/tests/parser/should_compile/T14189.stderr
• testsuite/tests/parser/should_fail/T16270h.hs
• testsuite/tests/plugins/plugins09.stdout
• testsuite/tests/plugins/plugins10.stdout
• testsuite/tests/plugins/plugins11.stdout
• testsuite/tests/plugins/static-plugins.stdout
• + testsuite/tests/th/T27013th.hs
• testsuite/tests/th/all.T
• utils/haddock/haddock-api/src/Haddock/Interface.hs

The diff was not included because it is too large.