How to synthesize a higher-kinded type parameter?

[TomasMikula]

I need to synthesize polymorphic function with a higher-kinded type parameter, such as

def fancyIdentity[F[_], A](fa: F[A]): F[A]
// or
val fancyIdentity: [F[_], A] => F[A] => F[A]

How do I create type for such method/function?

Note that PolyType takes TypeBounds:

/** Type of the definition of a method taking a list of type parameters. It's return type may be a MethodType. */
type PolyType <: MethodOrPoly

val PolyType: PolyTypeModule

trait PolyTypeModule { this: PolyType.type =>
  def apply(paramNames: List[String])(
    paramBoundsExp: PolyType => List[TypeBounds], // How to specify the kind of F[_] as TypeBounds?
    resultTypeExp: PolyType => TypeRepr
  ): PolyType
}

However, when I print out the tree structure of a higher-kinded type parameter, I get back a LambdaTypeTree, not TypeBoundsTree.

I am using Scala 3.4.0.

[TomasMikula]

To answer my own question: higher-kinds can be represented as TypeBounds with an upper bound of TypeLambda.

For example,

TypeBounds(
  low = TypeRepr.of[Nothing],
  hi  = TypeLambda(
    List("X"),
    _ => List(TypeBounds.empty), 
    _ => TypeRepr.of[Any]
  )
)

are bounds of a type parameter F[_].

The resulting TypeBounds can then be used in construction of PolyType.