Incorrect `children queried before class was discovered` error when typeCheckErrors is used

[jchyb]

Compiler version

3.3.0, main (8c311a0)

Minimized code

macro.scala

object Macro {
  import scala.quoted.*

  def subtypesImpl[A: Type](using quotes: Quotes): Expr[String] = {
    import quotes.reflect.*
    TypeRepr.of[A].typeSymbol.children // causes the error
    '{""}
  }

  inline def subtypes[A]: String = ${ subtypesImpl[A] }
}

test.scala

class Test {

  def test(): Unit = {
    scala.compiletime.testing.typeCheckErrors("Macro.subtypes[fixture.Shape]")
  }
}

package fixture {

  sealed trait Shape
  case class Circle(center: Int, rad: Double) extends Shape

  object Inner {
    case class Circle2(center: Int, rad: Double) extends Shape
  }
}

Output

-- Error: test.scala:14:15 ------------------------------------------------------
14 |    case class Circle2(center: Int, rad: Double) extends Shape
   |               ^
   |children of trait Shape were already queried before class Circle2 was discovered.
   |As a remedy, you could move class Circle2 on the same nesting level as trait Shape.

Expectation

Code should compile, as it does when either the code inside typeCheckErrors is extracted outside of that method.

Original minimization by @MateuszKubuszok with usage context: here

[jchyb]

This issue unfortunately will not be fixed. The limitation mentioned in the error message is clear and expected. Apparently these kinds of symbol loading issues were a frequent problem in scala 2, which is why this limitation was chosen for non-standard symbol loading contexts (like the macro entry being in the same file). An experimental fix was prepared with #18484, however in addition to it being not performant, it would force us to spend more time later on related issues (as the limitation would then be made inconsistent). A workaround fix here is to move the macro call outside of the enum definition.