Scala 3: derivation for sealed traits with case objects

[susliko]

Problem

An attempt to derive ElementEncoder for sealed trait with case object implementations results in compilation error in Scala 3, while compiles in Scala 2

 sealed trait Foo derives ElementEncoder
   object Foo:
     case object A extends Foo derives ElementEncoder
     case object B extends Foo derives ElementEncoder

[error] 60 |      sealed trait Foo derives ElementEncoder
[error]    |                               ^
[error]    |Exception occurred while executing macro expansion.
[error]    |java.lang.AssertionError: assertion failed
[error]    |    at scala.runtime.Scala3RunTime$.assertFailed(Scala3RunTime.scala:11)
[error]    |    at scala.quoted.runtime.impl.QuotesImpl$reflect$TypeIdent$.apply(QuotesImpl.scala:1093)
[error]    |    at scala.quoted.runtime.impl.QuotesImpl$reflect$TypeIdent$.apply(QuotesImpl.scala:1092)
[error]    |    at ru.tinkoff.phobos.derivation.common$.extractSumTypeChildren$$anonfun$1(common.scala:79)
[error]    |    at scala.collection.immutable.List.map(List.scala:246)
[error]    |    at ru.tinkoff.phobos.derivation.common$.extractSumTypeChildren(common.scala:79)
[error]    |    at ru.tinkoff.phobos.derivation.encoder$.deriveSum$$anonfun$1(encoder.scala:180)
[error]    |    at ru.tinkoff.phobos.derivation.encoder$.deriveSum$$anonfun$adapted$1(encoder.scala:195)
[error]    |    ... dotc frames
[error]    |    at ru.tinkoff.phobos.derivation.encoder$.deriveSum(encoder.scala:195)
[error]    |    at ru.tinkoff.phobos.derivation.encoder$.deriveElementEncoderImpl(encoder.scala:37)
[error]    |
[error]    |----------------------------------------------------------------------------
[error]    |Inline stack trace
[error]    |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
[error]    |This location contains code that was inlined from encoder.scala:19
[error] 19 |    ${deriveElementEncoderImpl('{config})}
[error]    |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[error]    |- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
[error]    |This location contains code that was inlined from encoder.scala:19
[error]  8 |    encoder.deriveElementEncoder[T](ElementCodecConfig.default)
[error]    |    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Expected behavior

ElementEncoder is derived and works as follows

implicit val encoder: XmlEncoder[Foo] = XmlEncoder.fromElementEncoder("foo")
assert(XmlEncoder[Foo].encode(Foo.A) == Right(
  """<?xml version='1.0' encoding='UTF-8'?>
        <foo xmlns:ans1="http://www.w3.org/2001/XMLSchema-instance" ans1:type="A"/>
 """))

[valentiay]

Closed by #283