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Marge Bot pushed to branch master at Glasgow Haskell Compiler / GHC

Commits:

e34cb6da

by Adam Gundry at 2026-03-20T12:20:00-04:00

ghci: Mention active language edition in startup banner

Per GHC proposal 632, this makes the GHCi startup banner include
the active language edition, plus an indication of whether this
was the default (as opposed to being explicitly selected via an
option such as `-XGHC2024`). For example:

```
$ ghci
GHCi, version 9.14.1: https://www.haskell.org/ghc/  :? for help
Using default language edition: GHC2024
ghci>
```

Fixes #26037.

2 changed files:

ghc/GHCi/UI.hs
ghc/Main.hs

Changes:

ghc/GHCi/UI.hs

@@ -23,7 +23,8 @@ module GHCi.UI (
          GhciSettings(..),
          defaultGhciSettings,
          ghciCommands,
 -        ghciWelcomeMsg
 +        ghciWelcomeMsg,
 +        languageEditionMsg
      ) where
  -- GHCi
@@ -199,6 +200,10 @@ versionString = "GHCi, version " ++ cProjectVersion
  ghciWelcomeMsg :: String
  ghciWelcomeMsg = versionString ++ ": https://www.haskell.org/ghc/  :? for help"
 +languageEditionMsg :: Maybe Language -> String
 +languageEditionMsg Nothing     = "Using default language edition: " ++ show defaultLanguage
 +languageEditionMsg (Just lang) = "Using language edition: " ++ show lang
++
  ghciCommands :: [Command]
  ghciCommands = map mkCmd [
    -- Hugs users are accustomed to :e, so make sure it doesn't overlap

ghc/Main.hs

@@ -37,7 +37,7 @@ import GHC.Platform
  import GHC.Platform.Host
  #if defined(HAVE_INTERNAL_INTERPRETER)
 -import GHCi.UI              ( interactiveUI, ghciWelcomeMsg, defaultGhciSettings )
 +import GHCi.UI              ( interactiveUI, ghciWelcomeMsg, defaultGhciSettings, languageEditionMsg )
  #endif
  import GHC.Runtime.Loader   ( loadFrontendPlugin, initializeSessionPlugins )
@@ -334,7 +334,9 @@ showBanner _postLoadMode dflags = do
  #if defined(HAVE_INTERNAL_INTERPRETER)
     -- Show the GHCi banner
 -   when (isInteractiveMode _postLoadMode && verb >= 1) $ putStrLn ghciWelcomeMsg
 +   when (isInteractiveMode _postLoadMode && verb >= 1) $
 +    do putStrLn ghciWelcomeMsg
 +       putStrLn $ languageEditionMsg (language dflags)
  #endif
     -- Display details of the configuration in verbose mode