A verifier error occurs when this program is compiled and run.
A value class that extends an abstract value class results in a VerifierError when passed as an argument.

If the superclass is not abstract, the program succeeds.

Error Text:
Exception in thread "main" java.lang.VerifyError: Bad type on operand stack
Exception Details:
  Location:
    AbstractValueClass.main([Ljava/lang/String;)V @6: invokevirtual
  Reason:
    Type 'AbstractValueClass$A' (current frame, stack[1]) is not assignable to 'AbstractValueClass$T'
  Current Frame:
    bci: @6
    flags: { }
    locals: { '[Ljava/lang/String;', 'AbstractValueClass$A' }
    stack: { 'AbstractValueClass$A', 'AbstractValueClass$A' }
  Bytecode:
    0000000: b800 074c 2b2b b600 0cb1


The source is:

public class AbstractValueClass {

    public static void main(String[] args) {
        A a = new A();
        a.doit(a);
    }
    public static abstract value class T {
        public abstract void doit(T t);
    }

    public static final value class A extends T {
        public void doit(T t) {
            System.out.println(t);
        }
    }
    public static final value class B extends T {
        public void doit(T t) {
            System.out.println(t);
        }
    }
}