GHC 9.0 compatibility

[sheaf]

This patch adds GHC 9.0 support relative to generic-lens-1.2.0.1.
I'm still using this version of generic-lens as I make extensive use of constrained traversals, which were removed in the 2.0 release.

I couldn't find a suitable branch to apply this to, but this patch was done on top of e4f6890.

[anka-213]

Now that #130 is merged, this can probably be closed.

[sheaf]

This is a patch to generic-lens-1.2, not generic-lens-2.1. That means it's not superseded by #130.

[andreasabel]

@sheaf: The Gods have not heard your prayer, it seems. Is generic-lens-1 still relevant for you today? Maybe you have a fork?

[sheaf]

@sheaf: The Gods have not heard your prayer, it seems. Is generic-lens-1 still relevant for you today? Maybe you have a fork?

Yes, it is relevant to me because I use the constrained traversals that generic-lens-1 provides. I have a fork here.

[michaelpj]

I think we would need to create a release branch in order to do this nicely. Is this still important to you @sheaf ?

[sheaf]

I think we would need to create a release branch in order to do this nicely. Is this still important to you @sheaf ?

Yes, I am still using generic-lens-1 in several of my projects. The branch in this thread compiles on GHC 9.8 (although some version bumps might be necessary, I just used --allow-newer).

[sheaf]

If you can provide a branch I would be happy to rebase the changes in this PR, perhaps with some additional changes to squash the current warnings. I'm not sure which newer commits might need to be backported (if any can be).

[michaelpj]

Do the things you need have to be in generic-lens? I wonder if it would be simpler for you to maintain your own package that just added the things that you need, then you could use newer generic-lens also?