Marge Bot pushed to branch wip/marge_bot_batch_merge_job at Glasgow Haskell Compiler / GHC

Commits:

• 94b62aa7
  by Simon Peyton Jones at 2025-09-08T03:37:14-04:00

  Refactor ForAllCo
  
  This is a pure refactor, addressing #26389.
  
  It arranges that the kind coercion in a ForAllCo is a MCoercion, rather
  than a plain Coercion, thus removing redundancy in the common case.
  See (FC8) in Note [ForAllCo]
  
  It's a nice cleanup.
  

• 624afa4a
  by sheaf at 2025-09-08T03:38:05-04:00

  Use tcMkScaledFunTys in matchExpectedFunTys
  
  We should use tcMkScaledFunTys rather than mkScaledFunTys in
  GHC.Tc.Utils.Unify.matchExpectedFunTys, as the latter crashes
  when the kind of the result type is a bare metavariable.
  We know the result is always Type-like, so we don't need scaledFunTys
  to try to rediscover that from the kind.
  
  Fixes #26277
  

• 0975d2b6
  by sheaf at 2025-09-08T03:38:54-04:00

  Revert "Remove hptAllFamInstances usage during upsweep"
  
  This reverts commit 3bf6720eff5e86e673568e756161e6d6150eb440.
  

• 0cf34176
  by soulomoon at 2025-09-08T03:38:54-04:00

  Family consistency checks: add test for #26154
  
  This commit adds the test T26154, to make sure that GHC doesn't crash
  when performing type family consistency checks. This test case
  was extracted from Agda.
  
  Fixes #26154
  

• 4eb7bbd1
  by Simon Peyton Jones at 2025-09-08T12:24:45-04:00

  Fix a scoping error in Specialise
  
  This small patch fixes #26329, which triggered a scoping error.
  
  Test is in T21391, with -fpolymorphic-specialisation enabled
  

• 5ddfe1af
  by sheaf at 2025-09-08T12:24:51-04:00

  Deep subsumption: unify mults without tcEqMult
  
  As seen in #26332, we may well end up with a non-reflexive multiplicity
  coercion when doing deep subsumption. We should do the same thing that
  we do without deep subsumption: unify the multiplicities normally,
  without requiring that the coercion is reflexive (which is what
  'tcEqMult' was doing).
  
  Fixes #26332
  

38 changed files:

• compiler/GHC/Core/Coercion.hs
• compiler/GHC/Core/Coercion.hs-boot
• compiler/GHC/Core/Coercion/Opt.hs
• compiler/GHC/Core/Lint.hs
• compiler/GHC/Core/Opt/Arity.hs
• compiler/GHC/Core/Opt/Specialise.hs
• compiler/GHC/Core/Reduction.hs
• compiler/GHC/Core/TyCo/FVs.hs
• compiler/GHC/Core/TyCo/Rep.hs
• compiler/GHC/Core/TyCo/Subst.hs
• compiler/GHC/Core/TyCo/Tidy.hs
• compiler/GHC/Core/Type.hs
• compiler/GHC/Core/Unify.hs
• compiler/GHC/CoreToIface.hs
• compiler/GHC/Driver/Env.hs
• compiler/GHC/Iface/Rename.hs
• compiler/GHC/Iface/Syntax.hs
• compiler/GHC/Iface/Type.hs
• compiler/GHC/IfaceToCore.hs
• compiler/GHC/Tc/Instance/Family.hs
• compiler/GHC/Tc/Module.hs
• compiler/GHC/Tc/TyCl/Utils.hs
• compiler/GHC/Tc/Utils/TcMType.hs
• compiler/GHC/Tc/Utils/TcType.hs
• compiler/GHC/Tc/Utils/Unify.hs
• compiler/GHC/Types/Id/Make.hs
• compiler/GHC/Unit/Home/Graph.hs
• compiler/GHC/Unit/Home/PackageTable.hs
• + testsuite/tests/linear/should_compile/T26332.hs
• testsuite/tests/linear/should_compile/all.T
• testsuite/tests/simplCore/should_compile/OpaqueNoCastWW.stderr
• + testsuite/tests/typecheck/should_compile/T26154.hs
• + testsuite/tests/typecheck/should_compile/T26154_A.hs
• + testsuite/tests/typecheck/should_compile/T26154_B.hs
• + testsuite/tests/typecheck/should_compile/T26154_B.hs-boot
• + testsuite/tests/typecheck/should_compile/T26154_Other.hs
• + testsuite/tests/typecheck/should_compile/T26277.hs
• testsuite/tests/typecheck/should_compile/all.T

The diff was not included because it is too large.