[ghc-steering-committee] #380 GHC2021: Current status

Joachim Breitner mail at joachim-breitner.de
Fri Dec 4 12:41:14 UTC 2020


Am Freitag, den 04.12.2020, 07:33 -0500 schrieb Eric Seidel:
> Is the expectation that GHC2021 remains the new default behavior, or
> will GHC2022 replace it as the default? I ask because tying these
> standards to GHC’s default behavior will make it much harder to
> correct mistakes or migrate to new designs of extensions (eg
> LambdaCase). Requiring an explicit opt-in to a GHC20XX standard means
> that users can upgrade to a new compiler and adapt to the new
> standard separately, which is very useful in larger enterprises. 

The use case you are describing (larger enterprises) probably mean you
are using Cabal, which forces you to declare a default-language
anyways. So that makes it opt-in, and all is well, I hope.

The “default” mode, as far as I know (please correct me if I am wrong)
mainly applies to your one-shot script that you run, and of course
interactive use in GHCI. Especially for the latter, I find it very
appealing to have the full syntax without turning on extensions, hence
my hope that the latest GHC202x is the default. And with these modes,
some breakage is acceptable maybe.

Do others see this differently?


Joachim Breitner
  mail at joachim-breitner.de

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