qscalac -Xprint:lambdalift sandbox/test.scala
sandbox/test.scala:2: error: Implementation restriction: access of method x$1 in class Bar from class C$1, would require illegal premature access to the unconstructed `this` of class Bar
class Bar extends Foo({ def x = 1; class C { x } })
                                             ^
[[syntax trees at end of                lambdalift]] // test.scala
package <empty> {
  class Foo extends Object {
    <paramaccessor> private[this] val foo: Object = _;
    def <init>(foo: Object): Foo = {
      Foo.super.<init>();
      ()
    }
  };
  class Bar extends Foo {
    def <init>(): Bar = {
      Bar.super.<init>({
        scala.runtime.BoxedUnit.UNIT
      });
      ()
    };
    final <static> def x$1(): Int = 1;
    class C$1 extends Object {
      def <init>(): Bar#C$1 = {
        C$1.super.<init>();
        ()
      };
      <empty>.x$1()
    }
  }
}

one error found