fix: enable UUID field overrides with patch

[hughsimpson]

There seems to have been a regression in the 1.7.x release, where patching a UUID field failed compilation. The problem is not limited to UUIDs, but applies to patches where a field is any pojo class with a single constructor and no matching accessors.

The fix I've proposed here is not an elegant one, but it does seem to work; the basic approach is just to forbid TransformProductToProductRule from applying where From <:< To actually pretty elegant, we just perform the last subtype rule on patches before the product rule

[MateuszKubuszok]

Probably the same problem as with #683 and would require similar fix to #684 - since Patchers are reimplemented as specialized withFallbacks, fallback issues propagate to Patchers:

• something prevented subtyping rule to apply
• subtyping and implicits are skipped without trying only by non-empty overrides
• so in this case overrides should have been empty but weren't
• Patchers are without overrides -> non-empty overrides had to be some fallbacks in TransformationContext

I would have to be debugged with enableMacrosLogging, but I probably won't have the time for it anytime soon. If you are interested I'd start with https://github.com/scalalandio/chimney/blob/master/chimney/src/main/scala/io/scalaland/chimney/internal/compiletime/derivation/transformer/rules/TransformProductToProductRuleModule.scala and see how fallbacks are propagated there. Maybe they shouldn't be if:

• we're using fallback
• FallbackFrom <:< To
• other overrides are empty

but that's just a quick guess. Other option might be that Patcher's Implicit/Subtyping rule should be special cased for this example, like a few other rules.

[hughsimpson]

Cheers. I'll try to look into this myself in the next couple of days

[hughsimpson]

@MateuszKubuszok this is the best working fix that I could manage on the issue... let me know what you think, or if there's a better solution that strikes you.

[MateuszKubuszok]

If it pass all tests, then it's good. :) Thank you!

[hughsimpson]

Brilliant! Thanks for the prompt review and release! 🙏