Final methods in traits are not compiled as final #11485
Description
In 2.13.0-RC1, if we write this simple code
import java.lang.reflect.Modifier.isFinal
trait HaveFinalMethod {
def normalMethod: String = "normal"
final def finalMethod: String = "final"
}
class Child extends HaveFinalMethod
object Main {
def main(args: Array[String]): Unit = {
println(isFinal(classOf[HaveFinalMethod].getMethod("normalMethod").getModifiers)) //false
println(isFinal(classOf[HaveFinalMethod].getMethod("finalMethod").getModifiers)) //false but should be true!
println(isFinal(classOf[Child].getMethod("normalMethod").getModifiers)) //false
println(isFinal(classOf[Child].getMethod("finalMethod").getModifiers)) //true (as it should be)
}
}Then we'll see how finalMethod in HaveFinalMethod is not actually marked as final, which, on top of being inconsistent with what happens when we test the same on Child, causes issues with frameworks that use reflection.
if we make Child a trait instead of a class, then the problem is also present when inspecting finalMethod.
trait HaveFinalMethod {
def normalMethod: String = "normal"
final def finalMethod: String = "final"
}
trait Child extends HaveFinalMethod
object Main {
def main(args: Array[String]): Unit = {
println(isFinal(classOf[HaveFinalMethod].getMethod("normalMethod").getModifiers)) //false
println(isFinal(classOf[HaveFinalMethod].getMethod("finalMethod").getModifiers)) //false but should be true!
println(isFinal(classOf[Child].getMethod("normalMethod").getModifiers)) //false
println(isFinal(classOf[Child].getMethod("finalMethod").getModifiers)) //false but should be true!
}
}