1. Compile the sample test.
2. Start jdb:
$ jdb -classpath . -XX:+EnableValhalla Test
3. Set breakpoint on the line with System.out.println()
> stop at Test:11
4. Run to breakpoint
> run
5. Invoke "set" cmd
> set v1.v2=v1.v2

Expected result:
java.lang.IllegalArgumentException: Cannot set value of final field

Actual result:
#
# A fatal error has been detected by the Java Runtime Environment:
#
# SIGSEGV (0xb) at pc=0x00000001037f7144, pid=63500, tid=42755
#
# JRE version: OpenJDK Runtime Environment (12.0) (build 12-internal+0-adhoc.datitov.valhalla)
# Java VM: OpenJDK 64-Bit Server VM (12-internal+0-adhoc.datitov.valhalla, mixed mode, compressed oops, g1 gc, bsd-amd64)
# Problematic frame:
# V [libjvm.dylib+0x3f7144] jni_IsInstanceOf+0xa2
#
# No core dump will be written. Core dumps have been disabled. To enable core dumping, try "ulimit -c unlimited" before starting Java again
#
# An error report file with more information is saved as:
# /Users/datitov/src/valhalla/hs_err_pid63500.log
#
# If you would like to submit a bug report, please visit:
# http://bugreport.java.com/bugreport/crash.jsp
#
com.sun.jdi.VMDisconnectedException
at jdk.jdi/com.sun.tools.jdi.TargetVM.waitForReply(TargetVM.java:310)
at jdk.jdi/com.sun.tools.jdi.VirtualMachineImpl.waitForTargetReply(VirtualMachineImpl.java:1145)
at jdk.jdi/com.sun.tools.jdi.PacketStream.waitForReply(PacketStream.java:87)
at jdk.jdi/com.sun.tools.jdi.JDWP$ObjectReference$GetValues.waitForReply(JDWP.java:4519)
at jdk.jdi/com.sun.tools.jdi.JDWP$ObjectReference$GetValues.process(JDWP.java:4489)
at jdk.jdi/com.sun.tools.jdi.ObjectReferenceImpl.getValues(ObjectReferenceImpl.java:229)
at jdk.jdi/com.sun.tools.jdi.ObjectReferenceImpl.getValue(ObjectReferenceImpl.java:183)
at jdk.jdi/com.sun.tools.example.debug.expr.LValue$LValueInstanceMember.getValue(LValue.java:496)
at jdk.jdi/com.sun.tools.example.debug.expr.LValue.interiorGetValue(LValue.java:136)
at jdk.jdi/com.sun.tools.example.debug.expr.LValue.setValue(LValue.java:86)
at jdk.jdi/com.sun.tools.example.debug.expr.ExpressionParser.Assignment(ExpressionParser.java:264)
at jdk.jdi/com.sun.tools.example.debug.expr.ExpressionParser.Expression(ExpressionParser.java:229)

The application has been disconnected
at jdk.jdi/com.sun.tools.example.debug.expr.ExpressionParser.evaluate(ExpressionParser.java:75)
at jdk.jdi/com.sun.tools.example.debug.tty.Commands.evaluate(Commands.java:114)
at jdk.jdi/com.sun.tools.example.debug.tty.Commands.doPrint(Commands.java:1653)
at jdk.jdi/com.sun.tools.example.debug.tty.Commands$3.action(Commands.java:1679)
at jdk.jdi/com.sun.tools.example.debug.tty.Commands$AsyncExecution$1.run(Commands.java:66)
 v1.val1 = v1.val1 = null



================================
public class Test {


  public static void main(String[] args){

      MyValue2 v2 = new MyValue2(12,'c');
      MyValue1 v1 = new MyValue1(v2);

      System.out.println("v1 = " + v1);
      System.out.println("v2 = " + v2);
  }

    public final __ByValue static class MyValue1 {
        MyValue2 val1;
        public MyValue1(MyValue2 v){
          val1 = v;
        }
    }

    public final __ByValue static class MyValue2 {
        int a;
        char b;

        public MyValue2(int a, char b){
          this.a = a;
          this.b = b;
        }
    }
    
}