GHC version support

[avdv]

• define a clear GHC version support range (keep this economical w.r.t. test coverage).

  See GHC release status page: https://gitlab.haskell.org/ghc/ghc/-/wikis/GHC-Status

• evaluate test coverage and expand where needed

  • e.g. GHC bindist patches undergo start-script tests.
  • but changes to rules are not checked on the full GHC version range

• keep up-to-date

  • GHC upgrade(s)
  • what do we do on the blockers for ARM cross-compilation support?
  • can we use tooling (dependabot/renovate) to stay up-to-date going forward?

Tasks

Beta Give feedback

1. Add full support for GHC 9.4 bindist #1933
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2. add full support for GHC 9.6 bindist #1986
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3. add full support for GHC 9.4 nixpkgs #1987
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4. add full support for GHC 9.6 nixpkgs #2031
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5. add full support for GHC 9.8 bindist #2081
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6. add full support for GHC 9.8 nixpkgs #2082
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7. Remove old GHC versions #2093
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[avdv]

Ideally, we should strive to support (and test) the recent stable GHC releases:

Current Stable Releases

• 9.8.1
• 9.6.3
• 9.4.8
• 9.2.8

Also, we should take into account the supported GHC versions from stackage:

• 9.2.8 -> LTS 20.26
• 9.4.8 -> LTS 21.24
• 9.6.3 -> nightly
• 9.8.1 -> nightly

Note: apparently, GHC 9.2.x has been demoted from stable to an "old" release, as it is no longer listed under "Current Stable Releases" on the download page.

[aherrmann]

@avdv is this one done now or is there still work remaining here?

[avdv]

is this one done now or is there still work remaining here?

We want to also support GHC 9.8 and eventually remove GHC 9.2 from testing since it is not a stable release anymore (but that can wait until we decide it's the right time)

[aherrmann]

@avdv Thanks for clarifying, sounds good!