Build failure with GHC-8.2

[phadej]

Failed to build Cabal-syntax-3.12.0.0.

src/Distribution/Types/ForeignLib.hs:168:13: error:
    Ambiguous occurrence ‘<>’
    It could refer to either ‘Distribution.Compat.Prelude.<>’,
                             imported from ‘Distribution.Compat.Prelude’ at src/Distribution/Types/ForeignLib.hs:18:1-34
                             (and originally defined in ‘Data.Semigroup’)
                          or ‘Data.Monoid.<>’,
                             imported from ‘Data.Monoid’ at src/Distribution/Types/ForeignLib.hs:31:1-18

Have someone forgot adjusting lowerbounds? Has Cabal-syntax dropped support for GHC-8.0 and GHC-8.2 (I dont' see a mention in the changelog).

[phadej]

The bad commit is 54183f2, old GHC support breakage seems unintentional.

[ffaf1]

It passed old GHCs validate workflow, so I am puzzled.

[Mikolaj]

But the problem is when building with GHC-8.2? It's out of the support window. Oldest tested for compilation is GHC 8.6.5.

I don't think we announce when GHCs drop out of our support window. Should we? It happens without any action. We could announce when we spot it and adjust CI. If so, that should be added to the criteria stating when a changelog is necessary.

[Mikolaj]

Have someone forgot adjusting lowerbounds?

That is a problem, though. Whenever we drop a GHC from CI we should bump the bounds and I think usually we do, so it's not unclear, I think.

[phadej]

First, please make a Hackage revision so the builds are not failing and then we can discuss further.

This is criticial issue, you should act ASAP.

[ffaf1]

Which revision would fix this?

[Mikolaj]

I think Cabal-syntax bound on base. I think @phadej is right, especially that revisions can always be reverted once we do the same bump in a PR and reviewers point out how the revision could be improved.