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Magnolia typename typeArguments bug
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import magnolia._ | |
import scala.language.experimental.macros | |
case class TypeArguments[T](names: Vector[String]) { | |
override def toString: String = names.mkString("__") | |
} | |
object Bug { | |
type Typeclass[T] = TypeArguments[T] | |
def collectTypeArgs(t: TypeName): Vector[String] = Vector(t.short) ++ t.typeArguments.flatMap(collectTypeArgs) | |
def combine[T](ctx: CaseClass[Typeclass, T]): Typeclass[T] = TypeArguments(collectTypeArgs(ctx.typeName)) | |
def dispatch[T](ctx: SealedTrait[Typeclass, T]): Typeclass[T] = TypeArguments(collectTypeArgs(ctx.typeName)) | |
@debug | |
implicit def gen[T]: Typeclass[T] = macro Magnolia.gen[T] | |
} | |
case class Example[T](bug: T) | |
sealed trait ST | |
case object A extends ST | |
case class B[T](v: Example[T]) extends ST | |
type TheTypeAlias = Example[B[Example[A.type]]] | |
val plain = Bug.gen[Example[B[Example[A.type]]]] | |
object Eg { | |
type InScope[X] = Example[B[Example[X]]] | |
} | |
val alias = Bug.gen[TheTypeAlias] | |
val objTA = Bug.gen[Eg.InScope[A.type]] | |
if (plain != alias) { | |
println("Type parameters are lost!") | |
println(plain) | |
println("!=") | |
println(alias) | |
println(objTA) | |
} |
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