Attempt to fix Scala 3 enum in snippet.sc, instead reproduce an issue with TypeRepr.of[A].memberType(subtype)

[MateuszKubuszok]

When Scala CLI snippet.sc is used macro generates assertion errors when Scala 3 enum is used:

• recommended way of calculating the type is TypeRepr.of[A].memberType(subtypeSymbol)

• the current way is based on subtypeSymbol.typeRef which cannot be used for types defined in

  class SomeClass {
   type InnerType
  }

  and enum and each case becomes a type defined in another class when we use snippet.sc (interestingly, the issue does not appear for case objects nor case classes)

  • however this recommended solution also upcasts parametherless cases, so that children of

    enum Foo:
    case Bar(value: Int)
    case Baz

    are resolved to List(Foo.Bar, Foo) (which breaks macro in another way).

Once this is solved, all Scala 3 snippets in documentation with enums - which required:

@main def example: Unit = {
// actual code
}

can have the workaround removed.

See:

• https://github.com/scala/scala3/issues/20349
• https://github.com/scala/scala3/issues/19825

for the context (and why it's not so easy to "just fix in in the library").

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 89.53%. Comparing base (35f50d4) to head (7e16b56). Report is 7 commits behind head on master.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #533 +/- ## ========================================== + Coverage 87.72% 89.53% +1.81% ========================================== Files 136 104 -32 Lines 5440 2589 -2851 Branches 438 243 -195 ========================================== - Hits 4772 2318 -2454 + Misses 668 271 -397 ```

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[MateuszKubuszok]

I might consider some workaround where we'd fetch m: scala.deriving.Mirror.SumOf[A] and extract subtypes from m.MirroredElemLabels, but it has its own corner cases.

[MateuszKubuszok]

Until it's fixed in upstream it makes no sense to work on this issue. When it will, then we might need to start from scratch anyway, so closing for now.