scalareflectionimplicits

What is a "<refinement>" type gotten through a TypeTag?

I have a method:

import scala.reflect.runtime.universe.{TypeTag,typeOf}

def print[T:TypeTag] = println(typeOf[T].typeSymbol.name.toString)

Most of the time, print[MyClass] prints MyClass when invoked, but sometimes, it prints <refinement>?

I am working on a fairly complex system (multiple interconnecting jars, 100K lines of code), and I cannot seem to identify what determines if it is the one behaviour or the other. But if I knew what <refinement> means, or what triggers that, maybe I could?

Solution

  • Refinements could be explained as anonymous class type. E.g.

    import scala.reflect.runtime.universe.{TypeTag,typeOf}

def print[T:TypeTag] = println(typeOf[T].typeSymbol.name.toString)

class C
trait T

print[C with T]

type A = C with T

print[A]

    Output will be <refinement> in both cases.