Florian Ragwitz pushed to branch wip/rafl/meaningful-main-return at Glasgow Haskell Compiler / GHC

Commits:

• dd3a23b6
  by Florian Ragwitz at 2026-10-08T19:05:38-07:00

  Implement MeaningfulMainReturn
  
  As per ghc-proposal#631, with one small adjustment explained in the comments.
  
  Fixes #24848.
  

31 changed files:

• + changelog.d/MeaningfulMainReturn
• compiler/GHC/Builtin/KnownOccs.hs
• compiler/GHC/Driver/Flags.hs
• compiler/GHC/Driver/Session.hs
• compiler/GHC/Tc/Errors/Ppr.hs
• compiler/GHC/Tc/Errors/Types.hs
• compiler/GHC/Tc/Module.hs
• compiler/GHC/Types/Error/Codes.hs
• + docs/users_guide/exts/meaningful_main_return.rst
• docs/users_guide/exts/misc.rst
• docs/users_guide/using-warnings.rst
• libraries/base/src/GHC/Essentials.hs
• libraries/ghc-internal/src/GHC/Internal/LanguageExtensions.hs
• testsuite/tests/driver/T4437.hs
• + testsuite/tests/meaningful-main-return/MainReturn_constrained_disabled.stderr
• + testsuite/tests/meaningful-main-return/MainReturn_exit_code_alias_disabled.stderr
• + testsuite/tests/meaningful-main-return/MainReturn_exit_code_bottom_disabled.stderr
• + testsuite/tests/meaningful-main-return/MainReturn_exit_code_bottom_enabled_run.stderr
• + testsuite/tests/meaningful-main-return/MainReturn_exit_code_disabled.stderr
• + testsuite/tests/meaningful-main-return/MainReturn_exit_success_disabled.stderr
• + testsuite/tests/meaningful-main-return/MainReturn_family_always_exit_disabled.stderr
• + testsuite/tests/meaningful-main-return/MainReturn_family_invalid_disabled.stderr
• + testsuite/tests/meaningful-main-return/MainReturn_family_invalid_enabled.stderr
• + testsuite/tests/meaningful-main-return/MainReturn_family_stuck_disabled.stderr
• + testsuite/tests/meaningful-main-return/MainReturn_family_stuck_enabled.stderr
• + testsuite/tests/meaningful-main-return/MainReturn_int_disabled.stderr
• + testsuite/tests/meaningful-main-return/MainReturn_int_enabled.stderr
• + testsuite/tests/meaningful-main-return/MainReturn_newtype_disabled.stderr
• + testsuite/tests/meaningful-main-return/MainReturn_newtype_enabled.stderr
• + testsuite/tests/meaningful-main-return/MeaningfulMainReturn.hs
• + testsuite/tests/meaningful-main-return/all.T

The diff was not included because it is too large.