Gating against old GHC in Cabal files

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Thanks for the reference to other-extensions. It seems I should be making greater use of it, as it has that specific gating role.

That Stack message is Stack passing on Cabal’s Distribution.Simple.Error.exceptionMessage UnsupportedLanguageExtension.

I wondered if other-languages would be to default-language as other-extensions is to default-extensions but I found that:

  • other-extensions: while configuring, Cabal outputs a warning (Distribution.PackageDescription.Check.Warning.ppExplanation (UnknownExtensions unknownExtensions)) and then throws the exception.

  • other-languages: while configuring, Cabal outputs a warning (Distribution.PackageDescription.Check.Warning.ppExplanation (UnknownLanguages unknownLanguages)) and then ploughs on to the building step regardless.