The compiler is supposed to signal an error if an inherited variable
hides an up-level one. This code is in error, although a bug injavac
permits it:
        class A_ {
            int x;
        }
        class A {
            int x;
            class B extends A/*_*/ {
                B() {
                    System.out.println(x);
                }
            }
        }
 
(If you change "A/*_*/" to "A_", you'll get the correct diagnostic
from javac.)