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

Commits:

• d87b651f
  by Vladislav Zavialov at 2026-08-13T19:56:06-04:00

  Increase test coverage of diagnostics, batch 2
  
  Add test cases for the previously untested diagnostics:
    [GHC-26133] TcRnForeignImportPrimSafeAnn
    [GHC-68444] SumAltArityExceeded
    [GHC-63966] IllegalSumAlt
    [GHC-23882] IllegalDeclaration
    [GHC-60220] InvalidCCallImpent
    [GHC-18816] RecGadtNoCons
    [GHC-38140] GadtNoCons
    [GHC-37056] InvalidTypeInstanceHeader
    [GHC-78486] InvalidTyFamInstLHS
    [GHC-39639] DefaultDataInstDecl
    [GHC-78822] AssocDefaultNotAssoc
    [GHC-43510] NotSimpleUnliftedType
    [GHC-41843] IOResultExpected
    [GHC-07641] AtLeastOneArgExpected
    [GHC-52886] InvalidTopDecl
  
  Remove unused error constructors:
    [GHC-92057] ImportLookupAmbiguous
  

• d27b2159
  by Simon Jakobi at 2026-08-13T19:56:07-04:00

  testsuite: Drop peak_megabytes_allocated from LinkableUsage tests
  
  LinkableUsage01/02 collected all metrics with a 2% tolerance. For
  peak_megabytes_allocated, whose granularity is 1 MB, that window is
  under 0.7 MB at this test's ~34 MB peak, so any 1 MB step failed the
  test (#27613, #27489). Drop that metric: max_bytes_used guards the
  Linkable-retention property with byte granularity, at a tolerance
  that still comfortably exceeds the noise observed in CI.
  
  Assisted-by: Claude Fable 5
  

• 87d8f137
  by Simon Jakobi at 2026-08-13T19:56:07-04:00

  testsuite: Don't truncate fractional baselines when computing bounds
  
  RelativeMetricAcceptanceWindow.get_bounds truncated the baseline with
  int() before applying the tolerance. Baselines can be fractional (they
  are averaged over several measurements), so this skewed the acceptance
  window downwards: in #27613, a baseline of 33.67 at 2% tolerance
  yielded bounds (32, 34) instead of (32, 35), rejecting a measurement
  that was within tolerance.
  
  Assisted-by: Claude Fable 5
  

38 changed files:

• compiler/GHC/Tc/Errors/Ppr.hs
• compiler/GHC/Tc/Errors/Types.hs
• compiler/GHC/Types/Error/Codes.hs
• testsuite/driver/perf_notes.py
• testsuite/tests/bytecode/TLinkable/all.T
• testsuite/tests/diagnostic-codes/codes.stdout
• testsuite/tests/ffi/should_fail/all.T
• + testsuite/tests/ffi/should_fail/ccfail006.hs
• + testsuite/tests/ffi/should_fail/ccfail006.stderr
• + testsuite/tests/ffi/should_fail/ccfail007.hs
• + testsuite/tests/ffi/should_fail/ccfail007.stderr
• + testsuite/tests/ffi/should_fail/ccfail008.hs
• + testsuite/tests/ffi/should_fail/ccfail008.stderr
• + testsuite/tests/ffi/should_fail/ccfail009.hs
• + testsuite/tests/ffi/should_fail/ccfail009.stderr
• + testsuite/tests/th/AssocDefaultNotAssoc.hs
• + testsuite/tests/th/AssocDefaultNotAssoc.stderr
• + testsuite/tests/th/TH_InvalidTopDecl.hs
• + testsuite/tests/th/TH_InvalidTopDecl.stderr
• + testsuite/tests/th/TH_cvt_DefaultDataInstDecl.hs
• + testsuite/tests/th/TH_cvt_DefaultDataInstDecl.stderr
• + testsuite/tests/th/TH_cvt_GadtNoCons.hs
• + testsuite/tests/th/TH_cvt_GadtNoCons.stderr
• + testsuite/tests/th/TH_cvt_IllegalDeclaration.hs
• + testsuite/tests/th/TH_cvt_IllegalDeclaration.stderr
• + testsuite/tests/th/TH_cvt_IllegalSumAlt.hs
• + testsuite/tests/th/TH_cvt_IllegalSumAlt.stderr
• + testsuite/tests/th/TH_cvt_InvalidCCallImpent.hs
• + testsuite/tests/th/TH_cvt_InvalidCCallImpent.stderr
• + testsuite/tests/th/TH_cvt_InvalidTyFamInstLHS.hs
• + testsuite/tests/th/TH_cvt_InvalidTyFamInstLHS.stderr
• + testsuite/tests/th/TH_cvt_InvalidTypeInstanceHeader.hs
• + testsuite/tests/th/TH_cvt_InvalidTypeInstanceHeader.stderr
• + testsuite/tests/th/TH_cvt_RecGadtNoCons.hs
• + testsuite/tests/th/TH_cvt_RecGadtNoCons.stderr
• + testsuite/tests/th/TH_cvt_SumAltArityExceeded.hs
• + testsuite/tests/th/TH_cvt_SumAltArityExceeded.stderr
• testsuite/tests/th/all.T

The diff was not included because it is too large.