Javac accepts this code:
abstract value class ValueParent {
    int b = 5;
}

value class ValueClass extends ValueParent {
    int a = b;
}

according to the spec this should be rejected as the initializer will run in the prologue phase and there is a reference to a super class field. If ValueClass is modified to the "equivalent" version below, javac does issue an error:

value class ValueClass extends ValueParent {
    int a;

    ValueClass() {
        a = b;
        super();
    }
}

reported by Ella Ananeva