runtime reflection: isVal return incorrect value for traits.

[rssh]

scala -version: 2.13.0

Example of code:

package x
  
trait X {

 val y: Int = 10

}


object  Main {

  import scala.reflect._
  import scala.reflect.api._


  def retrieveVals(u:Universe)(ownerType:u.Type): Iterable[u.TermSymbol] = {
     ownerType.members.filter(_.isTerm).map(_.asTerm).filter(x => x.isVal )
  }

  def main(args:Array[String]) {
     import scala.reflect.runtime.{universe=>ru}
     val mirror = ru.runtimeMirror(this.getClass.getClassLoader)
     val x = new X() {}
     val im = mirror.reflect(x);
     val l = retrieveVals(ru)(im.symbol.typeSignature)
     Console.println(l)
  }

}

return empty list, i.e. isVal for y returns false.

[solarmosaic-kflorence]

Same problem for me (scala 2.12.11):

import scala.reflect.runtime.universe._

object Reflection {
  def getPublicValues[T: TypeTag](obj: T): List[String] = {
    def resolve(t: Type): List[String] =
      t.decls
        .collect {
          case m: ModuleSymbol => resolve(m.info)
          case s: TermSymbol if s.isVal => List(s.fullName)
        }
        .toList
        .flatten

    resolve(typeTag[T].tpe)
  }
}

object Test {
  val test = "test"
}

// scalatest
class TestSpec extends WordSpec {
  "getPublicValues" should {
    "get public values" in {
      Reflection.getPublicValues(Test) should be(List("test")) // => empty list
    }
  }
}

It seems to think that val test is a method (symbol.isMethod returns true and symbol.isVal returns false). Perhaps it is getting confused as an accessor, as symbol.accessed.isMethod returns false...

[solarmosaic-kflorence]

This seems to resolve it: case s: TermSymbol if !s.isMethod || (s.isAccessor && !s.accessed.isMethod)