I have code that uses Trees$Literal, which compiled fine under 2.11 and 2.12. In 2.13.0-M3 I get the error in the title. Did this change? An example full line of code that broke is this:
// Extract MapName annotation if present
val optionalMapName = member.annotations.find(_.tree.tpe =:= typeOf[MapName])
.map { index =>
index.tree.children(1).productElement(1).asInstanceOf[scala.reflect.internal.Trees$Literal].value().value
}.asInstanceOf[Option[String]]