Support ghc 9.12

[erikd]

No description provided.

[RyanGlScott]

Superseded by 75e1525.

I'll hold off on making a new th-desugar release until the corresponding changes in singletons are prepared (see goldfirere/singletons#619).

[erikd]

@RyanGlScott Wondering if I could have a template-haskell upper bound bump on Hackage so I can remove this from the allow-newerstanza in my cabal.project file?

[RyanGlScott]

The current version of th-desugar on Hackage doesn't properly support template-haskell-2.23.0.0, as that version of template-haskell introduces several additions to the AST (OrP, ForallE, ForallVisE, and ConstrainedE) that will simply cause th-desugar to crash if it encounters them. (See the changes that I had to make to account for these in #221.) I'd prefer to make a new, proper Hackage release of th-desugar that handles these rather than revising the existing Hackage release into a subtly broken state.

[RyanGlScott]

Relatedly, if you'd like to help, I'm trying to figure out what is causing the CI issues here. I think that is the only remaining blocker for releasing new version of th-desugar/singletons/etc. (which I usually release in tandem) to Hackage.